P PESTICIDE EXPOSURE ACCORDING TO THE CZECH TOXICOLOGICAL

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					Chem. Listy 101, s73−s310 (2007)                                          12. mezioborová česko-slovenská toxikologická konference


P46
PESTICIDE EXPOSURE ACCORDING TO THE CZECH TOXICOLOGICAL INFORMATION CENTRE
FROM 1997 TO 2005


HANA RAKOVCOVÁa, DANIELA PELCLOVÁa,                                     39 % women; in 2 % the gender was unknown. During the
BRONISLAVA ŘIČAŘOVÁa a TOMÁŠ NAVRÁTILb                                  years, the percentage of these calls slowly decreased from
                                                                        7.8 % in 1997 to 5.0 % in 2005.
a
  Toxicological Information Centre, Department of Oc-                        Veterinary calls represented only 1.4 % of all calls,
cupational Medicine, General University Hospital and                    but 12% of all calls due pesticides. The course of some
Charles University in Prague, First Faculty of Medicine,                intoxication was in life-threatening, with severe symptoms
b
  J. Heyrovský Institute of Physical Chemistry ASCR                     (4.6 %) or lethal (5.0 %).
v.v.i, Prague                                                                The exact numbers of inquiries in consecutive years
Rakovcova.Hana@vfn.cz                                                   are given in Table I. Among insecticides, the decrease was
                                                                        seen especially in the group of organophosphates and car-
                                                                        bamates. More detailed data is shown in Table II. About
Key words: Pesticides, Czech Toxicological Information
                                                                        79 % of all exposures occurred in the vegetation period
Centre, Rodenticides, Intoxication, Exposure,
                                                                        from April to October, and only 21 % calls in the other
                                                                        months.
Introduction                                                                 Pesticide poisoning was predominantly an accidental
                                                                        overdose. There were 91 % unintentional exposures, 6 %
      Pesticides became a part of our households and may                suicidal, 2.3 % occupational and 0.7 % due to aggressive
represent a danger, especially when they are ingested by                behavior. Ingestion accounted for 84 %, inhalation for
children or adults1,2. Some exposures lead to life-                     13 % and skin contamination for 3 %. The symptoms of
threatening intoxications3. However little has been pub-                intoxication were absent in 50.5 % of subjects. About
lished about the current situation and frequency of expo-               27.5 % of patients had mild symptoms, 8% medium, 1%
sures to these substances in Central Europe. The aim of                 severe, in the rest of the cases the symptoms were not
this study was to describe the development and severity of              known at the time of the call. Death was the reason of
exposures to pesticides, based on the calls to the Toxico-              phone call in 0.3 % of cases.
logical Information Centre, which serves to the Czech                        In exposures to organophosphates and carbamates,
population of approximately 10 million.                                 47.4 % of the subjects had no symptoms; 27.4 % had mild
                                                                        symptoms, 8 % medium and 3 % severe, in other calls they
Methods                                                                 were unknown. Death was known in 1.5 % calls. Only
                                                                        35 % calls concerned the children.
     Data taken from the Czech Toxicological Information                     In exposures to rodenticides 83 % patients were as-
Centre database from periods 1997−2005 were evaluated                   ymptomatic, 5 % had mild symptoms, only 1.8 % medium
retrospectively using electronic evidence system.                       and 2 % severe symptoms. In other calls the symptoms
                                                                        were not described. About 72 % calls involved children.
Results                                                                      In 2005, the hospitalization was found necessary only
                                                                        in 14.4 % of subjects. About 1/3 of them were sympto-
     Overall pesticide poisonings reached 4405 in this                  matic at the time of the call. Antidotal treatment was rec-
period and accounted for 6.3 % of total calls to the Toxico-            ommended in 1.6 % of calls only: one patient was given
logical Information Centre. Forty-eight % calls concerned               atropine, and the other phytomenadione. In 2005 only one
adults, 40 % children, and 12 % animals.                                lethal case was registered. It concerned post-mortem con-
     In human exposures, 59 % of calls involved men,                    sultation due to suicide with pirimicarb.

Table I
Inquiries concerning types of pesticides to the Toxicological Information Centre in the years 1997−2005

                     1997         1998         1999          2000          2001        2002         2003       2004        2005
Insecticides         224          291          335           189           198         217          192        183         153
Rodenticides         102          140          105           142           136         150          105        118         164
Herbicides            --           --           --            83           109         117           78         77          89
Other*                --           --           --           110           122         191          117         95          73
Total                326          431          440           524           565         675          492        473         479
* Fungicides, moluscocides, combination or unknown pesticides. -- Data not available, included into Other

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Chem. Listy 101, s73−s310 (2007)                                         12. mezioborová česko-slovenská toxikologická konference


Table II
Selected data from the inquiries concerning pesticides in the years 1997−2005
                1997         1998         1999         2000            2001         2002        2003         2004         2005
Female, %       38.7         42.0         37.5         40.8            38.1         37.7        42.8         40.9         41.8
Accidental, %   82.4         85.6         91.3         88.0            93.3         92.4        89.2         92.0         88.3
Ingestion, %    81.7         86.0         82.5         83.8            85.8         85.2        82.1         81.5         86.0
Age             22.9         21.8         23.0         22.9            25.7         26.6        29.9         27.6         24.6
(mean, SD)      (14.4)       (20.4)       (19.9)       (14.4)          (27.6)       (30.9)      (20.3)       (24.6)       (27.1)
Time            15.5 (7.0)   16.4 (5.7)   14.7 (6.8)   13.9 (7.7)      14.1 (8.3)   14.6        14.1 (6.6)   14.1 (6.6)   14.5 (7.9)
(mean, SD)                                                                          (10.7)
Month           6.9 (4.2)    6.5 (5.3)    6.3 (4.8)    6.8 (6.6)       6.6 (7.7)    6.6 (9.1)   6.4 (5.8)    6.4 (6.1)    6.4 (5.6)
(mean, SD)



Discussion                                                             Conclusions

      The development of inquiries to the Czech Toxico-                     Acute human pesticide exposure in our country is
logical Information Centre concerning pesticides is rela-              mainly accidental and has good prognosis in general, due
tively favorable. It is true especially for human poisonings,          to low toxicity of commercial products used. The number
as the most dangerous products had already been replaced               of calls to the Czech Toxicological Information Centre due
by less toxic products. It can be seen in the group of or-             to pesticides in the past 9 years is relatively stable and
ganophosphates insecticides that have been substituted by              shows a mild decrease since the year 2003. More impor-
other substances, i.e., synthetic pyrethroids with low toxic-          tant is the development of the spectrum of pesticides, in-
ity for the mammals. The situation was even better in the              gested by the patients either accidentally or intentionally.
group of rodenticides. In the Czech Republic, solely war-              During the past years, the number of calls concerning toxic
farin or superwarfarin based rodenticides are commercially             substances, such as organophosphates and carbamates
available, which explains the good course of ingestions of             insecticides slowly decreases. On the other hand, the num-
these products. Comparing with the situation in the years              ber of calls due to rodenticides mildly increased, however
1988−1989 (ref.1), the percentage of suicidal attempts with            no serious sequel has been recorded. Lower number of
pesticides from all exposures was not different from the               deaths is the most important difference from the situation
recent data. However, the severity of exposures substan-               in the late 80ies, both after suicidal and non-intentional
tially decreased. In the years 1988−1989, total 14 deaths              ingestions.
were recorded (7 after suicidal ingestions and 7 after
drinking pesticide non-intentionally from a soft-drink bot-               The study was supported by project
tle).                                                                  MSM0021620807.
      On the other hand, veterinary calls document a higher
danger for exposed animals, which is in agreement with                 REFERENCES
the literature4,5. One reason may be ingestion of a higher
dose of the pesticide, when the animals are left alone with-            1. Pelclová D., Picková J., Filipová J.: Čas. Lék. Čes.
out supervision. Another explanation is the repeated expo-                 130, 361 (1991).
sure, in some cases even intentional, i.e. by the neighbors,            2. Hruškovič I., Bátora I., Sagat T., Getlík A., Strnová J.,
which concerns especially rodenticides poisonings. In                      Milovský V., Zajíčkova M.: Česk. Pediatr. 39, 581
some instances improper use of antiparasitic preparations                  (1984).
caused the poisoning of cats and dogs.                                  3. Ritter L., Goushleff N. C. I., Arbuckle T., Cole D.,
                                                                           Raizenne M.: J. Toxicol. Env. Health 9, 441 (2006).
                                                                        4. Vejlupková J., Fenclová Z.: Prakt. Lék. 80, 4 (2000).
                                                                        5. Berny P.: J. Vet. Pharmacol. Ther. 30, 93 (2007).




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P47
ENVIRONMENTAL RISK FACTORS OF ALLERGIC DISEASES IN 5-YEAR-OLD CHILDREN



KATARÍNA RAUSOVÁa, ĽUBICA                                                Table I
PALKOVIČOVÁa, MONIKA URSÍNYOVÁa,                                         Relation of risk factors and prevalence of allergic diseases
VLASTA MAŠÁNOVÁa, EVA REICHRTOVÁa,                                       among Slovak children
PETER ČIŽNÁRb, LADISLAVA WSÓLOVÁa
                                                                         Risk Factors                            AD ARS RA                   AE          FA
a
  Research Base of the Slovak Medical University, Lim-                   Family history of AD                     **     **                   *
bová 14, 833 03 Bratislava, b Comenius University Medi-                  Maternal history of AD                  ***     **                   *
cal Faculty, 1st Pediatric Department, Limbová 1, 833 40
Bratislava, Slovak Republic                                              Paternal history of AD                   *                           *                 *
katarina.rausova@szu.sk                                                  Region type                              ** *  ***
                                                                         Type of delivery                                                    *
                                                                         Male gender                             **          *
Key words: allergic diseases, children, environmental pol-               Mother smoked in past                               *
lution, risk factors, heavy metals
                                                                         Exclusive breast                        *                                              *

                                                                         * P ≤ 0.05; ** P ≤ 0.01; *** P≤ 0.001
Introduction

     Rapid increase in the prevalence of allergic diseases               tions of lead (median 26.5 µg l−1), cadmium (median
(AD), which includes atopic eczema (AE), asthma respira-                 0.128 µg l−1) and mercury (median 0.42 µg l−1) in 5-year-
tory symptoms (ARS), rhinitis allergica (RA) and food                    old children’s blood, we find a negative trend between the
allergy (FA), in last decades and particularly in industrial-            Cd levels in blood and incidence of AD in regions with
ized regions is, besides genetic factors, ascribed to envi-              different environmental characteristics (fig. 1).
ronmental factors.                                                             Prevalence of allergic diseases, asthma respiratory
                                                                         symptoms and rhinitis allergica among children differed
Subjects and methods                                                     with respect to environmental characteristics of the re-
                                                                         gions. Statistically significant differences were found in
      The following methods were applied: follow-up                      the frequency of allergic diseases (fig. 2) between regions:
(years 1997−2003) of cohort of children (n=1997) from                    M/R and M/CH (P=0.01). Prevalence of asthma respira-
birth to 5 years of age (n=403) for allergic disease devel-              tory symptoms (fig. 3) differed between regions: CH/A
opment in environmentally different Slovak regions, an-                  (P=0.05) and CH/M (P=0.01). Prevalence of allergic rhini-
nual clinical examination of children by paediatric aller-               tis (fig. 4) was different between regions: R/M (P=0.001),
gists and administration of maternal questionnaires fo-                  R/CH, R/A and CH/M (P=0.01).
cused on socio-economic status, life style and risk factors.
Child’s peripheral blood collection for analyses of toxic
metals, analysis of Pb, Cd and Hg by atomic absorption
spectrometry (AAS) method, statistical evaluation of asso-
ciations in EpiInfo v.6 and SPSS v.12.                                                         40                                            0,16
                                                                                                        0,148
      Four selected Slovak regions were selected according
                                                                            Prevalence of AD




                                                                                                                                                    conc. of Cd [ug/L]




                                                                                                                     0,137
to different predominant environmental pollutants and                                          30                                0,123       0,12
                                                                                                                                         0,109
anthropogenic activities: industrial chemistry (CH) with
                                                                                               20                                            0,08
                                                                                   [%]




the main sources of air pollution derived from chemical
industry, industrial metallurgy and mining (M), agricul-                                       10                                            0,04
tural (A) and rural (R) without any point source of indus-
trial pollution.                                                                                0                                            0,00
                                                                                                    R           CH           A           M
Results

     Comparison (Chi Square and Mantel-Haenszel tests)
of the prevalence of AD in 5-year-old children with rela-                                               median Cd [ µg/L]
tion to risk factors is given in Table I. Influence of parent’s
positive history of allergic diseases was confirmed. Al-                 Fig. 1. Prevalence of Allergic Diseases in 5-year-old children
though we did not find significant influence of concentra-               and Cd concentrations in blood


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                            40                                                                                      40




                                                                                             Prevalence of RA [%]
     Prevalence of AD [%]




                                                                           ** **
                            20                                                                                      20                                   *
                                                                                                                                                             ***
                                                                                                                                                         *
                                                                                                                                                     *
                                                                                                                     0
                             0
                                                                                                                         1       2           3       5
                                     1         2           3           5
                                                                                                                                     years
                                                   years                                                                     R       CH          A           M

                                 R            CH               A               M

                                                                                          Fig. 4. Development of Rhinitis Allergica
Fig. 2. Development of Allergic Diseases

                                                                                          Conclusions

                                                                                               Negative trend of AD prevalence with respect to Cd
                            40                                                            blood levels support the knowledge of immunotoxic ef-
  Prevalence of ARS [%]




                                                                                          fects of Cd. In our previous work, negative correlation was
                                                                                          found between the concentrations of Cd and IgE levels in
                                                                                          cord blood1. Differences in AD prevalence among regions
                            20                                                            may result from different environmental exposures.


                                                                           * **
                                                                                              This work was supported by the Agency for U.S.-
                                                                                          Slovak Science and Technology Program 012/95; Open
                             0                                                            Society Foundation G 147/98; NPPZ 23 and Slovak Re-
                                     1         2           3           5                  search and Development Agency, APVT-21-025602.
                                                   years
                                         CH         R              A       M
                                                                                          REFERENCE

                                                                                           1. Reichrtova E., Lang-Dunlop A., Palkovicova L.,
Fig. 3. Development of Asthma Respiratory Symptoms                                            Ciznar P., Adamcakova A., Ursinyova M., Prachar,
                                                                                              V., McNabb S. J. N.: ACI International 14, 117
                                                                                              (2002).




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P48
HAZARD IDENTIFICATION OF BINARY CHEMICALS MIXTURES BY QSAR TECHNIQUES



MARIAN RUCKI, MILOŇ TICHÝ,                                               flow rate was 1.2 ml min−1. For analysis of samples gener-
IVETA HANZLÍKOVÁ, RÚT UZLOVÁ                                             ated in experiments was used isocratic mode 40 % A and
                                                                         60 % B. The wavelength of detection was 254 nm.
National Institute of Public Health, Šrobarova 48, 10042,
Praha 10, Czech Republic                                                 D e t e r mi n a t i o n o f K m i x
rucki@szu.cz                                                                  Coefficient of distribution Kmix was determined ac-
                                                                         cording to4, using following equation:
Introduction                                                                                                                  n

                                                                                                                             ∑1+ W
                                                                                                                                         Qi
     QSAR and QAAR techniques applying knowledge of
                                                                                                                             i =1
data on Tubifex tubifex test1,2 (EC50(T.t.)), R-analysis3                                             K1 =
                                                                                                                W
                                                                                                                  ×
                                                                                                                                         VKi
                                                                                                       mix             n             n
(analysis of plot of mixed EC50(T.t.) against molar frac-                                                       V
                                                                                                                      ∑Q − ∑ 1 + W
                                                                                                                                              Qi
                                                                                                                             i
tion of a binary mixture) and partition coefficient of com-                                                           i =1          i =1
pounds between n-octanol and water (log P) were used to                                                                                        VKi
                                                                                                                                                     (1)
identify additivity or non-additivity of acute toxicity in
mixtures of chemicals and to study their nature. The                     where W is a volume of the aqueous phase, V is a volume
Tubifex tubifex test takes 3 minutes exposure and was veri-              of the octanol phase, n is a number of compounds in the
fied by correlation with both log Kow and acute toxicity                 mixture, Qi is total amount of the compound i in the sys-
indices measured with fish and ciliates1.                                tem and Ki is partition coefficient of compound i. The
Materials and method                                                     value of Kmix is normalized, i.e. in case of additivity the
                                                                         resulting Kmix is equal 1.
      Following chemicals were used: 2-nitroanisole                            Scientific graphic and analyzing software ORIGIN®
(Aldrich, 99.9+ %), phenol (Aldrich, 99.9+ %), n-octanol                 was used for statistical calculations. The additivity was
(Aldrich, 99%), water (GORO AQUA 200, deionized,                         tested using chi-square test and t-test with Bonferonis cor-
filtered through 0.22 mm membrane).                                      rection.
D e t e r mi n a t i o n o f K o w                                       D e t e r mi n a t i o n o f E C 5 0
      The studied compound is added to a system of n-                          The inhibition of the movement of oligochaeta
octanol and water where the volume of both phases is ad-                 Tubifex was measured as the effective concentration that
justed according to the expected value of Kow. For each                  causes 50 % of maximal response. Batches of six worms
pair of tested compounds a series of binary mixtures with                were immersed in aqueous solutions of the binary mixtures
molar ratio of benzene 1.0, 0.9, 0.8, 0.6, 0.4, 0.2, 0.1, 0.05,          and the concentration – response curve was determined.
and 0.0 was prepared. Each series was then tested at a sum               The number of immobilized worms was counted in each
concentration of both compound to be 0.005, 0.02 and                     batch precisely three minutes after their immersion. The
0.2 mol l−1.                                                             measurement was repeated three times with each concen-
      The system was shaken gently until equilibrium was                 tration on various days and in triplicate on each day. The
achieved (5 to 10 hr) and then centrifuged to separate the               reproducibility of the measurements was checked by the
two phases, especially if an emulsion has formed. Both                   parallel determination of the EC50 for aqueous MnCl2
phases, i.e. the n-octanol and the aqueous phase, were                   solution1.
directly analyzed for both studied compounds using gas
chromatography or liquid chromatography. The GC sys-                     Results and discussion
tem used consisted of Agilent 6890N gas chromatograph                          Acute toxicity EC50 (normalized value) of binary
with Agilent 7683 series injector and FID detector. The                  mixture phenol-2-nitroanisole (fig. 1) is expressed as the
column used was J&W scientific capillary column (30 m ×                  inhibition of movement of oligochaeta Tubifex tubifex. The
0.25 mm × 0.25 m). Nitrogen (99.99 %) was used as                        dashed line shows EC50 in case of additivity (normalized
a carrying gas. Injection volume was 1 ml.                               value 1). The normalization was used for purpose of a
      The HPLC system used consisted of two ECOM LCP                     better understandable explanation of toxic effect of mix-
4020 pumps, a Knauer dynamic mixing chamber, and an                      ture and for mathematical modeling. Values of normalized
ECOM LCD 2083 UV/VIS detector. The column used was                       EC50 above dashed line indicate inhibition of the toxic
a ChromolithTM Performance RP-18e (4.6 × 100 mm) with                    effect and values below dashed line indicate synergistic
ChromolithTM Guard Cartrige RP-18e (4.6 × 5 mm) guard                    toxic effect.
column (Merck, Prague, CR). Mobile phase for pump A                            Fig. 2 represented partition coeficient Kow of 2-
consisted of degassed water and for pump B 4 : 1 metha-                  nitroanisole, fig. 3 partition coeficient Kow of phenol and
nol/water mixture. Injection volume was 20 µl and the                    fig. 4 normalized coefficient of distribution Kmix of the

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Chem. Listy 101, s73−s310 (2007)                                                               12. mezioborová česko-slovenská toxikologická konference


                            2,0                                                                                         32



                            1,8
                                                                                                                        30


                            1,6




                                                                                                          Kow(Phenol)
                                                                                                                        28
             EC50 (norm.)




                            1,4

                                                                                                                        26
                            1,2


                                                                                                                        24
                            1,0



                            0,8                                                                                              0,0   0,2   0,4              0,6     0,8     1,0
                                                                                                                                                RPhenol
                                  0,0   0,2    0,4               0,6    0,8     1,0
                                                     Rnitroanisole


Fig. 1. EC50 of the phenol-2-nitroanisole mixture                                            Fig. 3. Kow of the phenol in the phenol-2-nitroanisole mix-
                                                                                             ture

                            80
                                                                                                                  1,20

                            75                                                                                    1,15


                            70
     Kow (2-Nitroanisole)




                                                                                                                  1,10


                            65                                                                                    1,05
                                                                                                    Kmix(norm.)
                            60                                                                                    1,00


                                                                                                                  0,95
                            55

                                                                                                                  0,90
                            50

                                                                                                                  0,85
                            45

                                                                                                                  0,80
                            40                                                                                               0,0   0,2    0,4               0,6     0,8         1,0
                                  0,0   0,2   0,4              0,6     0,8    1,0                                                               RPhenol
                                                     RPhenol


Fig. 2. Kow of the 2-nitroanisole in the phenol-2-nitroanisole                               Fig. 4. Kmix of the phenol-2-nitroanisole mixture
mixture

mixture phenol-2-nitroanisole, total concentration of the                                        The research was financially supported by Internal
compounds were 0.02 mol l−1.                                                                 Grant Agency of Ministry of Health of Czech Republic no.
      In the real life, the exposure to chemicals in mixture                                 NR8780-3/2006, partly by European Union (European
is more common than exposure to single compounds. Re-                                        Commission, FP6 Contract no. 003956) and partly by
sulting activity should be different from additivity ap-                                     grant of Grant Agency of Czech Republic no. 203/06/1265
proach, widely used in studies on mixture toxicity5,6. The                                   and by National Institute of Public Health.
analysis indicates that the mixtures of industrial solvents
phenol and 2-nitroanisole indicates clear „mixture interac-                                  REFERENCES
tion“, i.e. inhibition or potentiation depending on ratio of
components in the mixture. An attempt to simulate the
relationship between EC50 and molar ratio of mixture with                                     1. Tichy M., Rucki M., Hanzlíková I., Roth Z.: ATLA
log Kow is shown.                                                                                35, 229 (2007).
      Using of Kmix for QSAR modeling seems to be not                                         2. Tichý M., Rucki M.: Pracov. Lék. 48, 225 (1996) (in
fully sufficient. As is shown at fig. 4, there are no big                                        Czech).
changes of the Kmix for whole range of the mixture. On the                                    3. Tichý M., Cikrt M., Roth Z., Rucki M.: SAR QSAR
other hand, the log Kow of phenol and 2-nitroanisole show                                        Environ. Res. 9, 155 (1998).
significant differences from log Kow for both pure com-                                       4. Verhaar H. J. M., Busser F. J. M., Hermens J. L. M.:
pounds. Especially the log Kow of 2-nitroanisole could                                           Environ. Sci. Tech. 29, 726 (1995).
explain the acute toxicity of phenol – 2-nitro-anisole. On                                    5. Hermens J. L. M., Canton H., Janssen P., de Jong R.:
fig. 2 is shown decrease of Kow for 2-nitro-anisole. It is                                       Aquat.Toxicol. 5, 315 (1984).
suggested that lower value of Kow of compound in the mix-                                     6. Broderius S. J., v knize: Aquatic Toxicology and Risk
ture lead to inhibition of toxicity of this mixture due to the                                   Assessment (Mayes M. A., Barron M. G., ed.), 14th
less accumulation of 2-nitro-anisole, which is more toxic                                        ed. American Society for Testing and Materials, Phila-
than the phenol, in an organic tissue of worms.                                                  delphia 1991.

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P49
THIODIGLYCOLIC ACID – INDICATOR OF METABOLIC UNEQUILIBRIUM



BRONISLAVA ŘIČAŘOVÁ, LENKA ČERNÁ                                        Experimental

Department of Occupational Diseases, First Faculty of                         The analysis of TDGA was carried out by the com-
Medicine; General University Hospital, Charles Univer-                  puter-controlled Eco-Tribo Polarograph using the software
sity, Na Bojišti 1, 128 00 Prague 2, Czech Republic                     Polar 5.1 version for Windows on hanging mercury drop
bronislava.balkova@vfn.cz                                               electrode (HMDE) (all Polaro-Sensors, Czech Republic).
                                                                        Other experiments were performed on mercury meniscus
Key words: thiodiglycolic acid, TDGA, metabolism,                       modified or polished silver solid amalgam electrodes16−21
creatine, glutathione                                                   and on solid composite electrodes22−29 to compare30 the
                                                                        results with those obtained on HMDE. The process of
                                                                        TDGA reduction on the mercury electrode surface was
Introduction                                                            studied in detail using Elimination Voltammetry with Lin-
                                                                        ear Scan31. For characterization of body composition and
     Thiodiglycolic, also thiodiacetic, mercaptodiacetic                of pending parameters the multi-frequency impedance
acid or dicarboxydimethyl sulfide, S(CH2COOH)2, TDGA,                   analyzer “In Body 3.0” was used.
is one of the normal products of human metabolism and it                      TDGA was analyzed, after pre-separation from urine
occurs at low concentrations in urine1,2. It is believed to be          on a column of powdered PVC and after elution by 0.2 M
formed in a number of natural metabolic pathways how-                   perchloric acid, by the D.C. voltammetric procedure de-
ever, the most frequently studied pathway involves the                  scribed in1,3. The common laboratory methods were used
formation of TDGA from two carbon (2C) released from                    for determination of other compounds determined parallel
carcinogenic xenobiotics (e.g., vinylchloride monomer,                  with TDGA, which were useful for elucidation of meta-
ethylene oxide, 1,2-dichloroethane, chloroalkyl ethers1−8).             bolic pathways (in blood: uric acid, folates, vitamin B12,
These 2C units are oxidized via cytochrome P450 to                      cholesterol, homocysteine (HoCySH), testosterone, corti-
chloroacetaldehyde, which reacts with reduced GSH3,8.                   sone; in urine: creatine, creatinine, pH, total proteins con-
From this point is this metabolic pathway common with                   tent). Their corrections for specific gravity were calculat-
that of natural formation of TDGA from glycine over gly-                ed14.
oxylic and glycolic acids3,9. The process in presence of
transaminases and vitamin B6 continues over S-carboxy-                  Results and discussion
methyl-L-cysteine and S-carboxymethyl lactic acid to
TDGA which in turn gets oxidized to thiodiglycol sulfox-                     The natural level of TDGA in urine of healthy volun-
ide3. A significant increase is observed when the organism              teers2 varies between 10 and 20 mg L−1. Its abnormally
is exposed to the above mentioned 2C units, to the cy-                  increase was found in the morning urine of individuals,
tostatics ifosfamide and thiotepa2,3, or to the S-carboxy-              who suffered from certain metabolic disorders14. The
methyl-L-cysteine10,11, or       to antihistamine Zyrtec                TDGA levels decreased substantially during the day. The
(cetirizine dihydrochloride)2.                                          time dependences of TDGA levels can be explained as the
     TDGA is also one of the final products of the degra-               result of fluctuations of the daily rhythm of thiolic sub-
dative pathway of thiodiglycol (TDG), which is produced                 stances14. Creatine, consumed regularly as a food supple-
by alkaline hydrolysis of mustard gas (bis(2-chlor-                     ment, increases the TDGA level in the morning urine.
ethylsulphide)) (MG)12,13. In accordance with the Chemi-                Creatine supplemented to groups of randomly selected
cal Weapons Convention a concept of chemical detoxifica-                individuals, in any time of day, increased excretion of
tion and complete biodegradation of organic products by                 TDGA rapidly within 4−8 hours following per oral intake
a biotechnological method using bacterias utilizing TDG                 of creatine. Normal ranges of urinary TDGA levels were
was studied by Ermakova et al. and Lee et al.12−14. TDGA                usually reached within the following 1−2 hours. The sup-
is one of the final products. Some bacterial strains can                plemented creatine mostly decreased the amount of nor-
therefore be used for bioremediation of MG contaminated                 mally excreted creatinine and increased the pH value of
soils. A considerations of metabolic formation and fate of              urine in the time of maximal TDGA excretion. The
TDGA, structurally an analogue of MG, the microbiologi-                 amount of excreted TDGA is specific for different indi-
cal studies on MG detoxification13 seem to offer interest-              viduals. It can be supposed that supplemented creatine
ing aspects. Therefore, TDGA was found in urine of Ira-                 reduces its endogenous production in humans. In accor-
nian victims of an alleged attack with MG15.                            dance with previous findings2,14, vitamin B12, p.o., in-
                                                                        creased the TDGA level independently of creatine supple-




                                                                 s264
Chem. Listy 101, s73−s310 (2007)                                        12. mezioborová česko-slovenská toxikologická konference


mentation, and did not affect the pH-value of urine. The               9. Navratil T., Petr M., Senholdova Z., Pristoupilova K.,
stimulation of TDGA excretion after vitamin B12 applica-                  Pristoupil T. I., Heyrovsky M., Pelclova D.,
tion is caused by disturbance of redox equilibria induced                 Kohlikova E.: Physiol. Res. 56, 113 (2007).
by an increased supply of thiolic substances. Supplementa-            10. Hofmann U., Eichelbaum M., Seefried S., Meese C.
tion of creatine increases the input of 1C and 2C units into              O.: Drug Metab. Dispos. 19, 222 (1991).
metabolic pathways, participated by TDGA. An increased                11. Steventon G. B.: Drug Metab. Dispos. 27, 1092
level of TDGA in urine indicates a disturbance of redox                   (1999).
equilibria in human body. Creatine supplementation af-                12. Lee T. S., Chan S. H., Weigand W. A., Bentley W. E.:
fects metabolism of thiocompounds and excretion of some                   Biotechnol. Prog. 16, 363 (2000).
compounds into blood and urine, the metabolism of which               13. Ermakova I. T., Starovoitov I. I., Tikhonova E. B.,
is connected with the synthesis of creatine or with its us-               Slepen'kin A. V., Kashparov K. I., Boronin A. M.:
age in the body. Therefore, the levels of folates, vitamin                Proc. Biochem. 38, 31 (2002).
B12, homocysteine in blood, the levels of creatine,                   14. Pristoupilova K., Pristoupil T. I., Navratil T.,
creatinine, TDGA, and pH in urine were followed and                       Heyrovsky M., Senholdova Z., Pelclova D.: Anal.
evaluated. The results were accomplished by data of bio-                  Lett. 38, 613 (2005).
impedance measurements. According to the changes in                   15. Wils E. R. J., Hulst A. G., Vanlaar J.: J. Anal. Toxi-
creatine, folates and vitamin B12 levels before and after                 col. 12, 15 (1988).
creatine administration in course of one month, it was pos-           16. Yosypchuk B., Novotny L.: Crit. Rev. Anal. Chem.
sible to divide the volunteers under study into 4 groups.                 32, 141 (2002).
Each of them is characterized by typical changes in levels            17. Fischer J., Barek J., Yosypchuk B., Navratil T.: Elec-
of the above mentioned substances. The results confirmed                  troanalysis 18, 127 (2006).
that creatine given as food supplement is used in human               18. Fadrna R., Yosypchuk B., Fojta M., Navratil T.,
body not only for creatine phosphate formation, but that it               Novotny L.: Anal. Lett. 37, 399 (2004).
affects the whole metabolic transformation and body con-              19. Barek J., Dodova E., Navaratil T., Yosypchuk B.,
stitution (mass, fat, and proteins).                                      Novotny L., Zima J.: Electroanalysis 15, 1778 (2003).
                                                                      20. Barek J., Fischer J., Navratil T., Peckova K., Yosyp-
     This research has been financially supported by the                  chuk B.: Sensors-Basel 6, 445 (2006).
MSMT CR (Research Project No. 0021620807). The au-                    21. Barek J., Fischer J., Navratil T., Peckova K., Yosyp-
thors express their great appreciation for critical reading,              chuk B., Zima J.: Electroanalysis, Accepted (2007).
comments, and for language correction to Michelle Rich-               22. Navratil T., Kopanica M.: Crit. Rev. Anal. Chem. 32,
ards.                                                                     153 (2002).
                                                                      23. Navratil T., Kopanica M.: Chem. Listy 96, 111
REFERENCES                                                                (2002).
                                                                      24. Navratil T., Kopanica M., Krista J.: Chem. Anal.
 1. Dlaskova Z., Navratil T., Heyrovsky M., Pelclova D.,                  (Warsaw) 48, 265 (2003).
    Novotny L.: Anal. Bioanal. Chem. 375, 164 (2003).                 25. Sebkova S., Navratil T., Kopanica M.: Anal. Lett. 38,
 2. Navratil T., Senholdova-Dlaskova Z., Heyrovsky M.,                    1747 (2005).
    Pristoupilova K., Pristoupil T. I., Pelclova D.: Anal.            26. Sebkova S., Navratil T., Kopanica M.: Anal. Lett. 36,
    Lett. 37, 1093 (2004).                                                2767 (2003).
 3. Senholdova-Dlaskova Z.: Ph.D. Thesis. University                  27. Sebkova S., Navratil T., Kopanica M.: Anal. Lett. 37,
    Pardubice, Pardubice 2002.                                            603 (2004).
 4. Samcova E.: Chem. Listy 88, 723 (1994).                           28. Navratil T., Senholdova Z., Shanmugam K., Barek J.:
 5. Samcova E., Kvasnicova V., Urban J., Jelinek I.,                      Electroanalysis 18, 201 (2006).
    Coufal P.: J. Chromatogr., A 847, 135 (1999).                     29. Navratil T., Sebkova S., Kopanica M.: Anal. Bioanal.
 6. Samcova E., Roth Z.: Pracovni Lekarstvi 47, 64                        Chem. 379, 294 (2004).
    (1995).                                                           30. Cizkova P., Navratil T., Sestakova I., Yosypchuk B.:
 7. Dlaskova Z., Dvorakova L., Navratil T., Basova P.:                    Electroanalysis 19, 161 (2007).
    Chem. Listy 95, 184 (2001).                                       31. Sander S., Navratil T., Novotny L.: Electroanalysis
 8. Ambrosi L., Soleo L., Elia G., Attimotelli R.: Suppl.                 15, 1513 (2003).
    Med. Lav. 80, 5 (1990).




                                                               s265
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P50
STUDY OF PEROXIDASE-MEDIATED OXIDATION OF CARCINOGENIC AZO DYE SUDAN I



MARCELA SEMANSKÁa, VÁCLAV MARTÍNEKa,                                                                                                                      creted in urine1, and of its oxidation by rat and human
JIŘÍ HUDEČEKa, PETR HODEKa, MARTIN DRA-                                                                                                                   hepatic microsomal CYP in vitro3,4. Besides the C-
ČÍNSKÝa,b, EVA FREIc, MARIE STIBOROVÁa                                                                                                                    hydroxylated metabolites, which are considered detoxica-
                                                                                                                                                          tion products, the benzenediazonium ion (BDI) formed by
a
  Department of Biochemistry, Faculty of Science, Charles                                                                                                 enzymatic splitting of the azo group of Sudan I was found
University in Prague, Albertov 2030, 128 40 Prague 2,                                                                                                     to react with DNA in vitro3−6 (fig. 1). The major DNA
b
  Institute of Organic Chemistry and Biochemistry, Acad-                                                                                                  adduct formed in this reaction has been characterized and
emy of Sciences of the Czech Republic, 166 10 Prague 6,                                                                                                   identified as the 8-(phenylazo)guanine adduct6. This ad-
Czech Republic, c Division of Molecular Toxicology, Ger-                                                                                                  duct was also found in liver DNA of rats exposed to Su-
man Cancer Research Center, 69120 Heidelberg, Ger-                                                                                                        dan I (ref.7). Sudan I and its C-hydroxylated metabolites
many                                                                                                                                                      are also oxidized by peroxidases, as a consequence DNA,
stiborov@natur.cuni.cz                                                                                                                                    RNA and protein adducts are formed5,8−12 (fig. 1). While
                                                                                                                                                          CYPs were found to be responsible for the activation of
Key words: chemical carcinogenesis, Sudan I, peroxidase,                                                                                                  Sudan I in human or animal liver, their limited role in the
chromatography, mass-spectroscopy                                                                                                                         in vivo metabolic activation of Sudan I in the urinary blad-
                                                                                                                                                          der should be taken into account. This organ has little or
                                                                                                                                                          no detectable CYP; peroxidases are, however, present at
Introduction                                                                                                                                              relatively high levels in this tissue. It the case of peroxi-
                                                                                                                                                          dase, the metabolites formed by this enzyme have, how-
      Sudan I [1-(phenylazo)-2-naphthalene, C.I. Solvent                                                                                                  ever, not been identified as yet. Therefore, the present
Yellow 14] was used as a food colorant in several countri-                                                                                                work was undertaken to isolate two major Sudan I peroxi-
es1, but it has been recommended as unsafe, because it                                                                                                    dase-mediated metabolites and characterize them partially
causes tumors in the liver or urinary bladder in rats, mice,                                                                                              by mass spectroscopy.
and rabbits, and is considered a possible carcinogen and
mutagen for man1,2. Nevertheless, it is widely used to color                                                                                              Materials and methods
materials such as hydrocarbon solvents, oils, fats, waxes,
plastics, printing inks, and shoe and floor polishes1,2.                                                                                                        Incubation mixtures contained the following in a final
While the metabolism of Sudan I is not understood in hu-                                                                                                  volume of 70 ml: 10 mM sodium phosphate buffer (pH 8.4),
mans, its metabolism has been characterized in rabbits1,                                                                                                  0.5 µmol horseradish peroxidase (HRP), 100 µmol Sudan I
where it is metabolized primarily in the liver by oxidative                                                                                               dissolved in methanol and 200 µmol H2O2. After incuba-
or reductive reactions. Oxidation of Sudan I catalyzed by                                                                                                 tion (37 °C, 20 min) the mixtures were extracted with ethyl
cytochrome P450 (CYP) enzymes and peroxidases, was                                                                                                        acetate (2 × 15 ml). The extracts were evaporated, dis-
investigated and helped us to resolve its carcinogenic                                                                                                    solved in a methanol, and separated on HPLC or TLC.
mechanism (for a review see3). C-Hydroxylated metabo-                                                                                                     Silica-gel TLC plates were developed in hexane-diethyl
lites 4’-OH-Sudan I and 6-OH-Sudan I were found to be                                                                                                     ether (1:3, v/v). Spots of Sudan I metabolites M1 and M2
the major products of Sudan I oxidation in vivo and ex-                                                                                                   with Rf of 2.14 and 1.93, respectively, were extracted with
                                                                                                                                                          methanol. Alternatively, the products were separated by
                                                                                                                                                          HPLC on a Tessek Separon Hema S 1000 (8.0 × 250 mm)
                                                                 H       O


DNA, RNA              Peroxidase 4'
                                                             N
                                                                 N
                                                                                                 CYP1A1                                                   C-18 column. Gradient elution (75−100 % methanol) with a
                                                                                                                                                          flow rate of 0.3−1.5 ml min−1 was used. Sudan I metabo-
                                                                                                 (CYP3A)                            HO
and protein
  adducts                                                                                                       +
                                                                                                                               HO

                              CYP1A1
                              (CYP3A)
                                                          Sudan I                                           N       N   +
                                                                                                                                                          lites were detected at 215, 254, 333 and 480 nm. Two
Peroxidase                                     CYP1A1                            6
                                                   (CYP3A)                                  Benzendiazonium                 Naphthalene-1,2-diol          product peaks with r.t. of 32 and 46 min (peaks 1 and 2 in
                                                                                                  ion
              N
                  H       O

                                                   HO                N
                                                                         H   O
                                                                                                                                                          fig. 1) were collected. Sudan I metabolites were analyzed
                                                                                                                                                          by mass spectroscopy. Spectra were measured using Es-
                  N
                                                                         N
                                                                                                                                         O




     6-OH-Sudan I                 OH
                                                        4'-OH-Sudan I                                + DNA
                                                                                                                                    O
                                                                                                                                                          quire 3000 Bruker Daltonics (APCI, ESI – positive ioniza-
                                                                                                                                                          tion).
         CYP                            CYP                          CYP                                                     1,2-Naphthoquinone
                                                                                                 O



                                                                                                                                                          Results and discussion
                                                   HO                                                 N
                          H   O
                                                                                            HN
    HO                N                                          H   O                                      N
                          N                   HO             N                                        N
                                                                                     H 2N        N              N
                                                                 N
                                                                                                                                    unknown
                                                                                                                               +
                                                                                                      DNA                           adducts
                                       OH                                                   8-Phenylazoguanine                                                 The absorption spectrum of the reaction mixture con-
    4',6-diOH-Sudan I                          3',4'-diOH-Sudan I                                 in DNA
                                                                                                                                                          taining Sudan I and peroxidase significantly changes dur-
                                                                                                                                                          ing the Sudan I oxidation (fig. 2). During the reaction, the
Fig. 1. Scheme of Sudan I metabolism                                                                                                                      absorption maximum at 480 nm (due to Sudan I) decreases

                                                                                                                                                   s266
   Chem. Listy 101, s73−s310 (2007)                                                                                                                                                                                                                    12. mezioborová česko-slovenská toxikologická konference


                                                                                                                                                                                                                                                their structures have not been elucidated yet. In the present
                                                                                                                                                                                                                                                paper we used two separation procedures (TLC and
                                                                                                                                                                                                                                                HPLC) to obtain individual Sudan I metabolites in purity
                                                                                                                                                                                                                                                sufficient for their partial characterization. HPLC utilizing
                                                                                                                                                                                                                                                a Tessek Separon Hema S 1000 C-18 column was origi-
                                                                                                                                                                                                                                                nally developed here and used for purification of the two
                                                                                                                                                                                                                                                major Sudan I oxidation products (M1 and M2, fig. 3).
                                                                                                                                                                                                                                                These products were characterized by their mass spectra
                                                                                                                                                                                                                                                (fig. 4).
                                                                                                                                                                                                                                                      In all cases the products decomposed during mass
                                                                                                                                                                                                                                                spectroscopy. The fragmentation peak at m/z 232 in the
   Fig. 2. Oxidation of Sudan I by the peroxidase/H2O2 system.                                                                                                                                                                                  metabolite M1 indicate the presence of the Sudan I mole-
   The samples (1 ml) contained 50 mM Na phospahte buffer pH                                                                                                                                                                                    cule without a hydroxyl group. The peak at m/z 405 sug-
   8.4, 0.2 mg horseradish peroxidase, 0.15 mM Sudan I, and 0.5 mM
                                                                                                                                                                                                                                                gests the presence of the ion composed from hydroxylated
   H2O2. The spectra were recorded sequentially at 0 min (−−−), 2.5
                                                                                                                                                                                                                                                Sudan I and another molecule of Sudan I, but without the
   min (− − −) and 10 min (. . . .)
                                                                                                                                                                                                                                                benzene ring and nitrogen atoms (fig. 4). The fragment
                                                                                                                                                                                                                                                peak at m/z 495 in the metabolite M2 indicates the ion
                                                                                                                                                                                                                                                composed of two Sudan I molecules (fig. 4). Moreover,
   whiles the absorbance at about 340 nm increases slightly                                                                                                                                                                                     fragmentation peaks at m/z 159, 172, 247, 389 (391) and
   (fig. 2). Sudan I contains a free hydroxyl group in its mole-                                                                                                                                                                                417 (fig. 4) seem to correspond to decomposition of the
   cule. Many phenolic compounds can serve as substrates                                                                                                                                                                                        Sudan I dimer molecule. Nevertheless, the real structure of
   for peroxidases, being oxidized to phenoxyl radicals which                                                                                                                                                                                   the both metabolites will be evaluated in detail using NMR
   will undergo secondary reactions in dependence on their                                                                                                                                                                                      spectroscopy. This work is under way in our laboratory.
   individual free radicals chemistries. This mechanism was
   also found by us previously for Sudan I as a substrate;                                                                                                                                                                                      Conclusion
   peroxidase oxidizes this carcinogen, giving rise to an oxy-
   gen-centered radical (naphthoxyl radical)11,12. The prod-                                                                                                                                                                                         The results of the present and previous studies9,11,12
   ucts formed during peroxidase-mediated Sudan I oxidation                                                                                                                                                                                     suggest that one-electron oxidation products (radicals) are
   includes BDI and C-hydroxy derivatives [6-OH-Sudan I                                                                                                                                                                                         the primary intermediates in the peroxidase-mediated oxi-
   and 4’,6-di(OH)-Sudan I]5. But major metabolites are un-                                                                                                                                                                                     dation of Sudan I. The fate of the primary free radical de-
   stable (sensitive to light and elevated temperature)5 and                                                                                                                                                                                    pends on the environment in which it exists. We found that

         Sudan I + HRP metabolites #17 200.0ul [modified by vasek]                                                                           480 nm             Sudan I + HRP metabolites #21 100.0ul                                                                                            480 nm     2000 Sudan I + HRP metabolites #50                 TESSEK SEPARON SILIKAGEL PHENYL                                          480 nm



             a                                                                                                                                                       b                                                                                                                                                   c
2000                                                                                                                                                    2000
         mAU                                                                                                                            WVL:480 nm              mAU                                                                                                                         WVL:480 nm           mAU                                                                                                               WVL:480 nm
                                                                                                                      63.392
                                                                                                                           1.500                                                                                                                                               1.500

800                                                                                                                                                     800                                                                                                                                                  800



600                                                                                                                                                     600                                                                                                                                                  600
                        1.000                                                                                                                    1.00                         1.000                                                                                                                  1.00

400                                                                                                                                                     400                                                                                                                                                  400



200                                                                                                                                                     200                                                                                                                                                  200


                  Flow: 0.300 ml/min                                                                                                                                     Flow: 0.300 ml/min


                                                                                       M1
000                                                                                                                                                     000                                                                                                                                                  000
                                                                                                                   100.0                                                                                                                                             100.0


 800                                             M2                                                                                                      800                                                                                                                                                 800



 600
                                                                              37.492
                                                                                                                                                         600
                                                                                                                                                                                              M1                                                                                                             600
                                                                                                                                                                                                                                                                                                                                                        M1
                                                                     32.467
 400                                                                                                                                                     400                                                                                                                                                 400

                                                                                                                                                                                                                                38.277                                                                                                                                              42.323
 200                                                                                                                                                     200                                                                                                                                                 200
                  %B: 0.0 %                                                                                                                      0.0                     %B: 0.0 %                                                                                                                   0.0
                                                                                                                                                                                                                                                                         63.979
                                                                                                                                               min                                                             26.388                                                                              min                                                                                                                                   min
   0                                                                                                                                                       0                                                                                                                                                   0
       0.0      5.0     10.0     15.0     20.0     25.0     30.0      35.0     40.0    45.0   50.0   55.0   60.0      65.0    70.0   75.0       83.0           0.0    5.0      10.0    15.0     20.0    25.0      30.0   35.0   40.0     45.0   50.0   55.0   60.0      65.0      70.0   75.0       83.0           0.0   5.0    10.0    15.0     20.0   25.0   30.0   35.0   40.0     45.0   50.0   55.0   60.0   65.0   70.0   75.0       83.0




   Fig. 3. HPLC of Sudan I metabolites formed by peroxidase (a) and their HPLC re-chromatography (b,c)




                                                                     a                                                                                                                                                                                                                           b




   Fig. 4. Mass spectra (APCI) of Sudan I metabolite M1 (a) and M2 (b)


                                                                                                                                                                                                                            s267
Chem. Listy 101, s73−s310 (2007)                                           12. mezioborová česko-slovenská toxikologická konference


the Sudan I reactive free radicals: (i) form additional prod-            REFERENCES
ucts; (ii) react with other compounds of potential physio-
logical interest (reaction with NADH, ascorbate)8,9,11,12,                1. IARC Sudan I. IARC Monographs, Vol. 8, pp. 225−
(iii) react with SH groups of glutathione (reducing Sudan I                  231. Lyon: IARC, 1975.
radicals with the formation of a thiyl radical12 and (iv)                 2. Moller P., Wallin H.: Mutat. Res. 462, 13 (2000).
react with macromolecules (DNA, RNA proteins) to form                     3. Stiborová M., Martínek V., Rýdlová H., Hodek P.,
potentially toxic adducts in vitro and in vivo5,8−12. Structure              Frei E.: Cancer Res. 62, 5678 (2002).
elucidation of the Sudan I-(deoxy)guanosine-adducts8,11                   4. Stiborová M., Asfaw B., Anzenbacher P., Lešetický
will be the objective of a future study.                                     L., Hodek P.: Cancer Lett. 40, 319 (1988).
                                                                          5. Stiborová M., Asfaw B., Anzenbacher P.: FEBS Lett.
    Supported by grants 303/05/2195, MSM 0021620808                          232, 387 (1988).
and 1M4635608802.                                                         6. Stiborová M., Asfaw B., Frei E., Schmeiser H. H.,
                                                                             Wiessler M.: Chem. Res. Toxicol. 8, 489 (1995).
Abbreviations                                                             7. Stiborová M., Martínek V., Schmeiser H H., Frei E.:
                                                                             Neuro Endocrinol. Lett. 27, 35 (2006).
APCI      atmospheric pressure chemical ionization                        8. Stiborová M., Frei E., Schmeiser H. H., Wiessler M.,
BDI       benzendiazonium ion                                                Hradec J.: Carcinogenesis 11, 1843 (1990).
CYP       cytochrome P450                                                 9. Stiborová M., Frei E., Anzenbacher P.: Biochem. Phy-
ESI       electrospray-ionization                                            siol. Pflanzen 187, 227 (1991).
HRP       horseradish peroxidase                                         10. Stiborová M., Frei E., Schmeiser H. H., Wiessler M.,
TLC       thin layer chromatography                                          Hradec J.: Cancer Lett. 68, 43 (1993).
                                                                         11. Stiborová M., Asfaw B., Frei E.: Gen. Physiol. Bi-
                                                                             ophys. 14, 39 (1995).
                                                                         12. Stiborová M., Asfaw B., Frei E., Schmeiser H. H.:
                                                                             Coll. Czech. Chem. Commun. 61, 962 (1996).




                                                                  s268
Chem. Listy 101, s73−s310 (2007)                                        12. mezioborová česko-slovenská toxikologická konference


P51
CANCER MORBIDITY AND MORTALITY IN WORKERS EXPOSED TO VINYL CHLORIDE MONOMER



ALENA SLÁMOVÁa, ZDENĚK ŠMERHOVSKÝb,                                   plant. At the time when this production was launched, the
EVA KUDLOVÁa                                                          effects of VCM on human organism have already been
                                                                      known, including the chronic and acute effects and car-
a
 Charles University, 1st Faculty of Medicine, Institute of            cinogenic hazards. All available information and hygienic
Hygiene & Epidemiology, Studničkova 7, 128 00 Prague                  instructions for the staff of the district hygienic station of
2, b National Institute of Public, Šrobárova 48, 100 42               the Central Bohemian locality that were in charge of the
Praha 10                                                              plant’s hygienic supervision ensure efficient environ-
aslam@lf1.cuni.cz                                                     mental health protection of the workers.

                                                                      C h a r a c t e r i s t i c s of t h e p r o d u c t i o n a n d
Key words: vinyl chloride-monomer (VCM), demon-
                                                                      the workplace conditions
strated chemical carcinogen, standardised mortality ratio
                                                                            VCM is produced in hermetically sealed columns in
Introduction                                                          the open. The initial substance is ethylene and chlorine.
                                                                      The maximum acceptable concentration (MAC) mean is
      The production of the most popular plastic material −           10 mg m−3, MAC limit is 30 mg m−3 – until June 2001 and
polyvinyl chloride (PVC) was started in 1933 and during               20 mg m−3 afterwards. Values measured at workplaces
the past 60 years has been applied in almost every indus-             were usually under the MAC value limits; only exception-
trial activity.                                                       ally they were higher but never exceeded 100 mg m−3.
      According to IARC Lyon Agency monograph of 1987
VCM is classified I. group as a demonstrated carcinogen3              Malignant tumours
with target effects on the liver2. Exposed workers showed
significantly increased incidence of liver tumours, mostly                  Vinyl chloride pilot plant production was started in
angiosarcoma (ASL), insignificant mortality rise for tu-              1974 full run production in 1977. Since 1974 until the end
mours in general, in particular higher incidence lung1,               of 2003, a total of 908 employees worked in the PVC pro-
brain cancers, and lymphosarcoma4.                                    duction plant with an average exposure of 9.4 years (SD
                                                                      9.09). There were a total of 208 women with an average
Materials and methods                                                 exposure of 6.7 (0.1–28.8) years and 700 men with an
                                                                      average exposure of 9.9 (0.1−29) years. Comparison of the
      Data about workers employed in the vinylchloride                cohort data with the National Cancer Register revealed 44
manufacturing plant from 1974 until the end of 2003 were              workers (15 women and 29 men) who were diagnosed
obtained from the factory card file. The health status study          with tumour disease by the end of 2003. Twenty seven of
of this manufacturing plant was designed as a retrospective           them died (6 women and 21 men). Angiosarcoma was not
cohort study exploiting data on the Czech population                  diagnosed, hepatoma was diagnosed twice, carcinoma of
health status provided by Institute of Health Information             pancreas three times, gall bladder twice, and lung and
and Statistics of the Czech Republic (IHIS) and National              bronchi nine times (data about smoking were not avail-
Cancer Register (NCR) also administered by IHIS. Mortal-              able). Analysis of malignant tumours morbidity and mor-
ity and morbidity of exposed workers was compared with                tality (MT) has shown that the observed MT mortality (27)
an external control group, which constituted total Czech              is statistically significantly different from the expected one
population. Data on the incidence of monitored phenom-                (10.7) in men – 21 observed deaths vs. 9.37 expected
ena specific for sex, five-year age groups, and calendar              (SMR 1.43; 95 % CI 1.43−3.36) as well as in women – 6
years were used in calculations. Indirect standardization             observed deaths vs. 1.35 expected (SMR 4.44; 95 % CI
was used to control potentially confounding effects of sex            2.18−8.26). Similar results were found also for total mor-
and age; changes in the morbidity a mortality trends in               tality and MT incidence (Table I).
particular calendar periods were also taken into considera-
tion.                                                                 Discussion
Results                                                                    Analysis results indicate statistically significantly
                                                                      increased deviation of the health status of observed/
V C M p r o d u c t i o n in C z e c h R e p u b l i c                followed up cohort of workers exposed to vinylchloride in
                                                                      comparison with the Czech population health status re-
    VCM, the polymerization of which produces polyvi-                 garding total mortality as well as tumour mortality and
nylchloride is in the Czech Republic produced by a single             morbidity. We are very careful in their interpretation as

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Table I
Standardized cancer mortality ratios according to calendar years

                  CANCER OCCURENCE
               EXPECTED                    OBSERVED                          FEMALE                        MALE
 Year    Female    Male     F+M     Female    Male     SMR              95% Cl         Sig.    SMR         95% Cl
 1980    0.022     0.147    0.169      1        0      45.26          4.10   211.02   0.012    0.00                      0.809
 1981    0.020     0.152    0.172      0        0      0.00                           0.254    0.00                      0.823
 1982    0.028     0.166    0.194      0        0      0.00                           0.399    0.00                      0.857
 1983    0.030     0.181    0.211      0        0      0.00                           0.411    0.00                      0.890
 1984    0.026     0.223    0.249      0        0      0.00                           0.391    0.00                      0.977
 1985    0.031     0.243    0.274      1        2      32.33          2.93   150.73   0.017    8.23     1.64    26.37    0.018
 1986    0.039     0.276    0.316      0        0      0.00                           0.456    0.00                      0.927
 1987    0.048     0.320    0.367      0        1      0.00                           0.496    3.13     0.28    12.17    0.227
 1988    0.054     0.331    0.385      0        3      0.00                           0.523    9.07     2.51    24.19    0.004
 1989    0.059     0.366    0.425      0        2      0.00                           0.543    5.47     1.09    17.53    0.042
 1990    0.069     0.415    0.484      0        2      0.00                           0.579    4.82     0.96    13.31    0.054
 1991    0.078     0.441    0.519      1        1      12.90          1.17    60.15   0.042    2.27     0.21    10.57    0.377
 1992    0.074     0.442    0.516      0        1      0.00                           0.597    2.26     0.21    10.54    0.338
 1993    0.087     0.442    0.529      0        1      0.00                           0.642    2.26     0.21    10.55    0.338
 1994    0.073     0.481    0.554      1        0      13.74          1.24    64.04   0.039    0.00                      0.656
 1995    0.079     0.474    0.553      0        0      0.00                           0.615    0.00                      0.663
 1996    0.064     0.495    0.559      0        0      0.00                           0.562    0.00                      0.672
 1997    0.069     0.528    0.597      0        1      0.00                           0.579    1.90     0.17     8.84    0.418
 1998    0.063     0.530    0.593      0        1      0.00                           0.558    1.89     0.17     8.80    0.420
 1999    0.061     0.427    0.487      1        0      16.50          1.50    76.94   0.032    0.00                      0.716
 2000    0.060     0.431    0.491      0        1      0.00                           0.547    2.32     0.21    10.81    0.328
 2001    0.058     0.441    0.499      0        3      0.00                           0.537    6.80     1.88    18.13    0.009
 2002    0.071     0.482    0.553      0        2      0.00                           0.585    4.15     0.83    13.30    0.073
 2003    0.029     0.426    0.455      1        0      35.04                          0.015    0.00                      0.717
 Total   1.353     9.372   10.725      6       21      4.44           2.18    8.26    0.003    2.24     1.43     3.36    0.001




evaluating the exposure of workers is very complicated                REFERENCES
because the individual length and intensity of exposures
are very different.                                                    1. Maroni M., Fanetti C. A: Int. Arch. Occup. Environ.
     All employees were included into the study even                      Health 79, 57 (2006).
those not expected to have been exposed to carcinogens or              2. Mastrangelo G., Fedeli U., Prilo G., Buja A.: Cancer
those who worked at the worksite for one month only. We                   Causes Control. 16, 189 (2005).
did not exclude these employees from the sample due to                 3. Vinyl chloride. IARC monographs on the evaluation
the total sample size. We have not calculated standardized                of carcinogenic risks to humans. 7, 1 (1987).
indexes for particular types of tumour diseases due to their           4. Ward E., Boffetta P., Andersen A.: Epidemiol. 12, 710
small numbers.                                                            (2001).




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P52
FREQUENCY OF TPMT FUNCTIONAL POLYMORPHISMS IN THE CZECH POPULATION



ONDŘEJ SLANAŘ, HELENA BUZKOVÁ,                                         Methods
KRISTÍNA PECHANDOVÁ, JOSEF MAREK,
FRANTIŠEK PERLÍK                                                             Two hundred and sixty-seven young healthy volun-
                                                                       teers (161 men and 106 women, aged 18−56 years) were
Charles University in Prague, 1st Faculty of Medicine, De-             included in the study after obtaining their written informed
partment of Pharmacology, Na Bojišti 1, 120 00 Praha 2                 consent. All subjects participating in the study were unre-
oslan@lf1.cuni.cz                                                      lated subjects of Czech nationality.
                                                                             Peripheral blood samples were collected from all
Key words: pharmacogenetics, single nucleotide polymor-                volunteers in 7 ml collecting tubes with ethylenediamine-
phism, thiopurine S-methyltransferase                                  tetraacetic acid (EDTA). Genomic DNA was subsequently
                                                                       isolated by a standard phenol-chlorophorm method and
                                                                       stored at 4 °C until analysis.
Introduction                                                                 PCR amplification was run in a MyCycler (Bio-Rad,
                                                                       USA) using primers as described previously and specified
     Azathioprine and its metabolite 6-mercaptopurine are              in Table I. Subsequent RFLP analysis produced fragments
thiopurines with the latter acting as a purine antimetabolite          specified in Table I, allele specific PCR was run for
which can inhibit purine biosynthesis by both de novo and              TPMT*2. The fragments were separated in 3 % agarose
salvage pathways. Metabolically, 6-mercaptopurine is                   gel and visualized by staining with ethidium bromide. The
converted by hypoxanthine phosphoribosyltransferase to                 primers were ordered at Sigma-Aldrich (St. Louis, USA),
activated 6-thioguanine nucleosides. These latter interme-             all other components of PCR reaction mix and Top Vision
diates are ultimately incorporated into DNA as false bases.            agarose were purchased from Fermentas (Lithuania).
Inactivation of 6-mercaptopurine and 6-mercaptopurine                        The study was approved by the Ethics Committee of
nucleosides is mediated by methylation with thiopurine S-              the General Teaching Hospital in Prague.
methyltransferase (TPMT) to inactive metabolites methyl-                     Expected genotype frequencies were calculated using
mercaptopurine or methylmercaptopurine nucleosides,                    Hardy–Weinberg equilibrium from the observed allelic
respectively. TPMT is well characterized cytosolic en-                 frequencies. Prevalence was compared by the chi-square
zyme, with several functionally important genetic poly-                test. Microsoft Excel 8.0 (Microsoft, USA) and Statgraph-
morphisms leading to decreased enzyme activity.                        ics Plus 3.1 (StatPoint, Inc., USA) were used for data han-
     There is substantial amount of evidence, which shows              dling.
that individual activity of TPMT is one of the major fac-
tors for wide variation in the metabolism, the drug effi-              Results
cacy, and mainly severe toxicity of thiopurine drugs1−5.
The patients, who have low or no detectable enzyme activ-                    Table II shows observed genotypes and respective
ity, suffer more frequently from myelotoxicity when                    allelic frequencies in our study. The most frequent allele
treated with standard doses of azathioprine. On the other              was TPMT*3A, while no subject carrying TPMT*3B al-
hand, subjects with high activity of the enzyme could have             lele was found. Totally 26 (9.7 %) subjects were found to
reduced clinical effect of the treatment. Genetic basis for            be heterozygous carriers of one of the variant alleles and 1
such a variation in TPMT activity is known only for defi-              (0.4 %) volunteer was homozygous poor metabolizer. The
cient states while no corresponding factors for ultra-rapid            distribution of genotypes was similar to the predicted num-
type of TPMT metabolism were found so far6.                            bers.


Table I
Sequences of the primers used, restriction enzymes and discrimative lenghths of fragments [bp]

Polymorphism       Primer name - sequence                                          Restriction enzyme        Fragment size
G460A                 P460F 5'-ATAACAGAGTGGGGAGGCTGC
                      P460R 5'-CTAGAACCCAGAAAA AGTATAG                                          Acc I          293/207
A719G                 P719R 5'-TGTTGGGATTACAGGTGTGAGCCAC
                      P719F 5'-CAGGCTTTAG CATAATTTTCAATTCCTC                                    Mwo I          365/267
G238C                 P2W 5'-GTATGATTTTAT GCAGGTTTG
                      P2M 5'-GTATGATTTTATGCAGGTTTC
                      P2C 5'-TAAATAGGAACCATCGGACAC                                                  −          254

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Table II
Number of subjects with specific TPMT genotypes and respective allelic frequencies
Polymorphism                      Observed genotypes           Alelic frequencies [%]
                                  w/w w/v v/v                  w          v
TPMT*2                            266      1    0              99.82      0.18
TPMT*3A                           244      22   1              95.52      4.48
TPMT*3B                           267      0    0              100.00     0.00
TPMT*3C                           264      3    0              99.44      0.56
w − wild-type allele, v − variant allele




Discussion                                                            European countries. These results also provide basal infor-
                                                                      mation for future pharmacogenetic and pharmacoeconomic
     Similarly to our findings, variant allele TPMT*3A                studies in the Czech population.
was reported as the most prevalent deficient allele in other
Caucasian populations, whereas TPMT*3C is the most                        This study has been supported by grants No. IGA MZ
frequent variant in Asian populations7,8.                             ČR NR9094, and MSM0021620849.
     A good correlation between high concentrations of
activated 6-thioguanine nucleosides and severe forms of               REFERENCES
bone marrow suppression in TPMT homozygous poor
metabolizers treated with usual doses of azathioprine has              1. Duley J. A., Florin T. H.: Ther. Drug. Monit. 27, 647
been well established. Some studies revealed similar pat-                 (2005).
tern of relationship between high levels of 6-thioguanine              2. Breen D. P., Marinaki A. M., Arenas M., Hayes P. C.:
nucleosides and clinical effects in heterozygous intermedi-               Liver Transpl. 11, 826 (2005).
ate metabolizers, but other authors did not report such                3. Krynetski E.Y., Evans W.E.: Pharmacology 61, 136
findings. Although there exists such a discrepancy be-                    (2000).
tween the data a screening for TPMT deficient patients                 4. Frohman E. M., Havrdova E., Levinson B., Slanar O.:
prior to beginning of azathioprine therapy seems to be cost               Mult. Scler. 12, 108 (2006).
effective approach9,10. Our data provide necessary basis,              5. Rosen R., Integlia M. J.: J. Pediatr. Gastroenterol.
for transferring the observed individual, social and eco-                 Nutr. 35, 695 (2002).
nomic consequences of TPMT deficiency from other Cau-                  6. Yates C. R., Krynetski E. Y., Loennechen T., Fessing
casians into the Czech population.                                        M. Y., Tai H. L., Pui C. H., Relling M. V., Evans W.
                                                                          E.: Ann. Intern. Med. 126, 608 (1997).
                                                                       7. Tavadia S., Mydlarski P., Reis M., Mittmann N., Pin-
Conclusions                                                               kerton S. N.: J. Am. Acad. Dermatol. 42, 628 (2000).
                                                                       8. Marra C., Esdaile J., Anis A.: J. Rheumatol. 29, 2507
     Our results show similar distribution of the most fre-               (2002).
quent variant TPMT alleles in comparison to other Cauca-               9. Collie-Duguid E. S., Pritchard S. C., Powrie R. H.:
sian populations. Therefore the consequences of azathio-                  Pharmacogenetics 9, 37 (1999).
prine therapy arising from TPMT deficiency can be ex-                 10. Kumagai K., Hiyama K., Ishioka S.: Pharmacogenet-
pected similar proportions as described in some other                     ics 11, 275 (2001).




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P53
OXIDATIVE DAMAGE AND ANTIOXIDANT DEFENCE IN THE PLASMA OF PEOPLE EXPOSED
TO MINERAL FIBRES


MARTA STARUCHOVÁa, KATARÍNA                                              investigated (21 to 58 years old), 43 controls (20 men, 23
VOLKOVOVÁa, CSILLA MIŠĽANOVÁa, ZUZANA                                    women and 27 non-smokers, 16 smokers) and 98 exposed
KOVÁČIKOVÁa, LADISLAVA WSÓLOVÁa,                                         (75 men, 23 women and 61 non-smokers, 37 smokers).
A. R. COLLINSb, LADISLAV STARUCHc,                                       The rock wool exposure lasted at least 5 years.
MÁRIA DUŠINSKÁa,d                                                             All subjects contributed a single blood donation in
                                                                         autumn. A urine sample was used for measurement of
a
  Research Base of Slovak Medical University, Limbová                    cotinine to determine smoking status. Blood was collected
12, 833 03 Bratislava, b Institute for Nutrition Research,               by venipuncture from fasted subjects, using an anticoagu-
University of Oslo, Norway, c Faculty of Chemical and                    lant as EDTA used for isolation of lymphocytes and eryth-
Food Technology,Slovak University of Technology, Brati-                  rocytes. The samples of plasma, lymphocytes and lympho-
slava, d Norwegian Institute of Air Research (NILU),                     cyte extracts were stored on ice until assayed or were fro-
Kjeller, Norway                                                          zen at −80 °C for various biochemical measurements.
marta.staruchova@szu.sk
                                                                         M e a s u r e me n t o f D N A d a m a g e a n d r e p a i r
Keywords: Rockwool, oxidative DNA damage, DNA re-
                                                                              The comet assay (single cell alkaline gel electropho-
pair; antioxidative enzymes
                                                                         resis)5 was applied to freshly isolated lymphocytes
                                                                         (Lymphoprep, Nycomed, Oslo, Norway) for measurement
Introduction                                                             of DNA strand breaks, oxidized bases and DNA alkyla-
                                                                         tion6,7. The assay for OGG1 activity5 was used to measure
      Oxidative damage of biomolecules (DNA, proteins,                   the ability of a cell-free lymphocyte extract to incise sub-
lipids) caused by free radicals is involved in the patho-                strate DNA containing 8-oxoGua6,7.
genesis of different diseases such as cancer, atherosclero-
sis, inflammation, etc.1 Cells respond to toxic levels of                M e a s u r e me n t o f a c t i v i t i e s o f a n t i o x i d a n t
reactive oxygen species (ROS) by activating a diverse                    e n z y me s
arrays of protective responses. This includes a complex
range of enzymatic antioxidants such as catalase (CAT),                       Erythrocytes were washed three times with isotonic
glutathione peroxidase (GPX), superoxide dismutase                       saline. Isolated erythrocytes were used for measurement of
(SOD), glutathione-S-transferase (GST) and non-                          activities of antioxidant enzymes. The activity of glu-
enzymatic antioxidants such as glutathione, tocopherols                  tathione peroxidase (GPx) was determined indirectly by
and carotenoids2. Oxidative repair mechanisms, includes                  oxidation of NADPH to NADP+ measured by the kinetic
DNA repair, protein and lipid repair, is degradation path-               method according to Paglia and Valentine8. Catalase
ways3.                                                                   (CAT) was measured spectrophotometrically by a modi-
      The adverse effect that arises from exposure to asbes-             fied method of Cavarocchi et al.9 and glutathione-S-
tos has stimulated an extensive research into the develop-               -transferase (GST) by a kinetic method according to Habig
ment of substitute materials. One such substitute is rock-               et al10. The activity of superoxide dismutase (SOD) was
wool, made from natural basic rock material, which is used               estimated by a commercial test (Randox lab, Ltd., U.K.).
mainly as isulation for thermal, acoustic and fire protection                 The index of the combined non-enzymatic antioxidant
of roofs, walls and floors. However, little is known about               capacity of plasma (FRAP) was measured spectropho-
the health effects of these fibres. The potentially harmful              tometrically according to Benzie and Strain11 ferric to fer-
effects of all types of respirable fibres are at present one of          rous ion reduction at low pH causes formation of a col-
the most important fields of interest in industrial hygiene4.            oured ferrous–tripyridyltriazine complex.
                                                                              Ceruloplasmin oxidase activity in plasma was assayed
Subjects and methods                                                     with the use of o-dianisidine dihydrochloride according to
                                                                         the method of Schosinsky et al.12
     In order to study the effect of rockwool exposure on                     Plasma vitamin C was detected by HPLC13. Lipid
oxidative DNA damage and lipid peroxidation, an epide-                   peroxidation was determined by the levels of malondialde-
miological study was conducted in a rockwool factory in                  hyde (MDA) using a modified HPLC method in plasma14.
Slovakia.
     To examine the interactions between fibre- and ciga-                Results and discussion
rette smoke- induced effects, the cohorts examined in-
cluded non-smokers as well as individuals smoking differ-                    Rockwool exposure induced elevation of DNA strand
ent numbers of cigarettes. Altogether 141 subjects were                  breaks in the lymphocytes of investigated subjects (P=


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0.05). When analysed according to sex and smoking habit,             molecules especially in the group of male non-smokers;
this effect was apparent only in the group of non smokers.           however, the optimal levels of antioxidants could have
DNA strand breaks were higher in exposed subjects com-               a protective effect.
pared to controls (P=0.004). The effect of occupational
                                                                         The work was supported by the E.C. grant,
exposure to rockwool on oxidative DNA damage and re-
                                                                     FIBRETOX contract No. QLK4-CT-1999-0162.
pair was already published by Dusinska et. al.15. DNA
repair of oxidative damage in lymphocytes of exposed                 REFERENCES
subjects was higher in group of men (P=0.02) compared to
women, and controls (P=0.07).                                         1. Ames B. N., Shigenaga M. K., Hagen T. M.: Proc.
     We found higher MDA levels in the group of all ex-                  Natl. Acad. Sci.U.S.A 90, 7915 (1993).
posed workers (P=0.025) and in exposed non-smokers                    2. Choudhary S., Xiao T., Srivastava S., Zhang W., Chan
(p=0.003) possibly as the consequence of significantly                   L. L., Vergara L. A., Van Kuijk F. J., Ansari N. H.:
suppressed activity of CPL-oxidase (P=0.02, 0.016 respec-                Toxicol. Appl. Pharmacol. 204, 122 (2005).
tively) and CAT in these groups (P=0.04, 0.012 respec-                3. Evans M. D., Dizdaroglu M., Cooke M. S.: Mutat.
tively). The activity of GST was affected by exposure to                 Res. 567, 1 (2004).
rockwool; the GST levels were significantly lower in the              4. Man-made Viterous Fibres, IARC Monographs, vol.
all exposed subjects (P=0.04), in the exposed non-smokers                81, IARC, Lyon 2002.
(P=0.03), and exposed men (P=0.007). Concentration of                 5. Collins A. R., Dusinska M., Horvathova E., Munro E.,
vitamin C in plasma and the FRAP were not affected by                    Savio M., Stetina R.: Mutagenesis 16, 297 (2001).
the rockwool exposure.                                                6. Collins A. R.: Mol. Biotech. 26, 249 (2004).
     There was a significant negative correlation between             7. Dusinska M., Collins A., Kazimirova A.,
the activity of GPX and MDA in the whole group                           Barancokova M., Harrington V., Volkovova K.,
(P=0.007) and in the exposed group, and between CAT                      Staruchova M., Horska A., Wsolova L., Kocan A.:
activity and MDA in the all subjects (P=0.009). We found                 Mutat. Res. 553, 91 (2004).
inverse correlations between activities of several antioxi-           8. Paglia D. E., Valentine W. N.: J. Lab. Clin. Med. 70,
dant enzymes (GPX, GST, and CAT) and DNA damage.                         58 (1967).
GST activity correlated inversely with oxidised purines               9. Cavarocchi N. C., England M. D., O'Brien J. F., Solis
measured as Endonuclease sensitive sites almost in all                   E., Russo P., Schaff H. V., Orszulak T. A., Pluth J. R.,
subgroups: in all subjects (P=0.002), in exposed (0.014),                Kaye M. P.: J. Surg. Res. 40, 519 (1986).
men (0.038), women (0.004), and exposed men (0.041).                 10. Habig W. H., Pabst M. J., Jakoby W. B.: J. Biol.
We found a significant negative correlations between                     Chem. 249, 7130 (1974).
DNA repair and GPX in all subjects as well as in control             11. Benzie I. F. F. and Strain J. J.: Anal. Biochem. 239,
men (P=0.03, 0.028 respectively) and CAT in all control                  70 (1996).
subjects and control men (P=0.019, 0.009 respectively).              12. Schosinsky K. H., Lehmann H. P., Beeler M. F.: Clin.
Interestingly we found the positive correlations between                 Chem. 20, 1556 (1974).
DNA repair and MDA in all subjects and in all exposed                13. Cerhata D., Bauerová A., Ginter E.: Ceska Slov.
(P=0.008, 0.026 respectively).                                           Farm. 43, 166 (1994).
                                                                     14. Richard M. J., Guiraud P., Meo J., Favier A.: J. Chro-
Conclusion                                                               matogr. 577, 9 (1992).
                                                                     15. Dusinska M., Barancokova M., Kazimirova A., Har-
    The presented results indicate that rockwool exposure                rington V., Volkovova K., Staruchova M., Horska A.,
induces an increase in the oxidative damage of bio-                      Wsolova L., Collins A.: Mutat. Res. 553, 103 (2004).




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P54
TLC PROOF OF INTOXICATION BY TAXUS BACCATA



JAN STŘÍBRNÝa,b, MICHAL DOGOŠIa, ZDENĚK                                sis: blood, urine, samples of the brain and lung tissue, sam-
ŠŇUPÁREKa, IVANA ČERNÁa, MILOŠ SOKOLa                                  ples of the liver and kidney tissue and stomach and duode-
                                                                       num content (pH 8). No blood alcohol was detected. Nor
a
 Vojenský ústav soudního lékařství ÚVN, U vojenské                     any volatile toxic compounds in the brain and lung tissue
nemocnice 1200, 169 02 Praha 6, b Fakulta vojenského                   were found. Toxicological analysis using GC/MS detected
zdravotnictví Univerzity obrany, Hradec Králové                        carboxy-tetrahydrocannabinol, caffeine and nicotine in the
jan.stribrny@uvn.cz                                                    blood. Morphological and anatomical evaluation of the
                                                                       mash plant material found in the stomach content detected
                                                                       the presence of Taxus baccata leaves (evaluation per-
Key words: Taxus, Taxine, TLC, intoxication
                                                                       formed by RNDr. Dagmar Nová).

Introduction                                                           Materials and methods

     The toxicity of yew (Taxus baccata) has been known                Material used
since antiquity. It was believed that as "a tree of death" it
endangered lives of those who stayed in its shade for                        Mixture of taxin B and isotaxin B prepared in the
a longer time. Yew was used in homicide, suicide, and as               Institute of Legal Medicine, University Hospital Münster.
an abortive. All parts of yew, except for the red epicarp of           Chromatographic plates Kieselgel 60 F254 Merck, Fast
the berries, are toxic. The toxicity of yew is attributed to           Blue B reagent (FBB), Ehrlich reagent, Drägendorff re-
taxin, a mixture of several pseudoalkaloids, in which the              agent, ethanol 96 %, organic solvents used in extraction
evidently dominant components are taxin B and isotaxin                 and preparation of mobile phases were p.a. purity, ammo-
B. These taxin alkaloids are cardiotoxic. Their effect can             nium hydroxide solution 26 % p.a., hydrochloric acid
be determined as soon as 1/2 hour after ingestion. Death               conc. p.a.
after 2 and 1/2 hours after ingestion of two handfuls of
yew leaves was reported1.                                              E x t r a c t i o n o f c o mp a r a t i v e p l a n t ma t e r i a l
     Description of toxicological proofs of yew poisoning
is not very frequent in literature. There is a description of               100 ml of 3.7 % hydrochloric acid was added to 50 g
intoxication evidence by thin layer chromatography2,3, of              of Taxus baccata leaves, the mixture was homogenized
the evidence achieved by chromatogram similarities be-                 and macerated for 1 hour, then filtered. The filtrate was
tween yew extract and extract of stomach content4 (GC/                 extracted twice with 250 ml diethyl ether and then aIka-
FID), of the finding of 3,5-dimethoxyphenol by gas chro-               lized to pH 10 with sodium hydroxide and extracted twice
matography5 (3,5-dimethoxyphenol is considered as                      with 250 ml diethyl ether. The acidic and basic extract was
a marker of yew ingestion) and the evidence of taxin B and             evaporated and the evaporates dissolved in 1.5 ml ethanol.
isotaxin B determined in biological material by liquid
chromatography with mass detector6,7.                                  E x t r a c t i o n o f s e c t i o n ma t e r i a l
     In the following paragraphs the authors describe
a case of lethal intoxication caused by the decoction of                     Samples of liver and kidney tissue (50 g) were ho-
yew leaves, and the proof of it by thin layer chromatogra-             mogenized, 24 hours soaked in acetone and ethanol mix-
phy (TLC).                                                             ture (450 ml, 7:3) and then the macerate was filtered and
                                                                       evaporated to 50 ml. The stomach content was diluted with
Case report                                                            distilled water and filtered. Urine, the macerate of the liver
                                                                       and kidney tissue, the filtrate of the stomach content and
     A 28-year-old man was found dead in the family                    the found brown liquid were acidified with hydrochloric
house. For toxicological analysis the police supplied                  acid to pH 3 and extracted 2 times with 250 ml diethyl
a brown liquid (pH 9) found in a bottle and a glass in the             ether. The water fractions were subsequently alkalized to
living room. Forensic autopsy stated the following: acute              pH 10 with the solution of sodium hydroxid and extracted
catarrhal esophagitis, acute gastritis, a mash of plant mate-          with 250 ml diethyl ether and 250 ml chloroform. Acidic
rial in the stomach and duodenum (in dry form 3.6 g),                  and basic extracts were vaporized and consequently dis-
epicranial, pleural and epicardial pete-chiae, brain swell-            solved in 1.5 ml ethanol. Further, urine was hydrolyzed
ing, haemorrhagical swelling of the lungs, acute venostasis            and after neutralization extracted with 250 ml diethyl
of the parenchymatous organs, and liquid status of the                 ether.
blood. The following was supplied for toxicological analy-



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M o b i l e p h a se                                                       The Drägendorff reagent reacts in colour with the
                                                                      taxin B / isotaxin B standard. In chromatographic condi-
A       ethyl acetate : ethanol : ammonium hydroxide solu-            tions mentioned above both the compounds do not sepa-
        tion 26 % = -36:2:2                                           rate and only one spot on the chromatogram appears
B       chloroform : ethanol : ammonium hydroxide solu-               (RfA=0.6; RfB=0.4). A presence of taxin B / isotaxin B
        tion 26 % = 38:2:1 / paper                                    was proved in the basic extract of stomach content. In the
                                                                      liver and kidney tissue extracts, as well as in the urine and
Abbreviations                                                         urine hydrolysate a presence of taxin B / isotaxin B was
                                                                      not detected.
RfA      retention factor in mobile phase A
RfB      retention factor in mobile phase B                           Conclusion

Results                                                                    On the basis of the described results, the authors as-
                                                                      sume that the intoxication with Taxus baccata can be
Fast BlueB detection                                                  proved analytically by the TLC method. With detection of
                                                                      Fast Blue B and Ehrlich reagent, compounds of corre-
     Some substances from acidic extract of yew show a                sponding character with substances contained in Taxus
very prominent colour reaction with the FBB reagent. In               baccata were identified. The presence of these substances
acidic extracts of stomach content, urine and the found               was proved in the stomach and duodenum content and
brown liquid FBB reagent proved a presence of substances              urine, whereas it was not detected in the liver and kidney
of corresponding character with substances contained in               tissue and urine hydrolysate. The Drägendorff reagent
the extract of Taxus baccata. A bright orange-red spot in             reacts with a number of substances present in the yew
the position RfA=0.8; RfB=0.4 was particularly persua-                leaves extract, particularly with substances contained in
sive. A presence of substances contained in Taxus baccata             the extract from basic water environment. Some spots on
extract was not determined in the liver and kidney tissue             the chromatogram of the yew basic extract correspond
nor in the urine hydrolysate. FBB reagent showed no col-              with the spots on the chromatogram of the stomach and
our reaction with taxin B / isotaxin B standard.                      duodenum content. The chromatogram is not clear enough
                                                                      because of multiple spots. The comparision of biological
Ehrlich reagent detection                                             material extracts with the taxin B / isotaxin B standard
                                                                      proved that one of the spots reacting positively with the
      With the Ehrlich reagent some substances from acidic            Drägendorff reagent on the chromatogram of the basic
and basic extracts of yew show a prominent colour reac-               extract of stomach and duodenum content is taxin B / iso-
tion after heating the chromatographic plate. In acidic and           taxin B. Under the stated chromatographic conditions there
basic extracts of the stomach content and urine Ehrlich               was no separation of taxin B from isotaxin B.
reagent proved a presence of substances of corresponding
character with substances contained in the extract of Taxus                The authors wish to thank Dr. J. Beike from Univer-
baccata. Particularly persuasive was a pink spot on the               sity Hospital Münster for supplying the taxin B / isotaxin B
chromatogram of the acidic extract in position RfA=0.8;               standard.
RfB=0.4. After heating the plate, intensified spots of blue-
violet colour showed on the chromatogram of basic extract
of yew, and two of them also appeared in the basic extract            REFERENCES
of stomach content (RfAl/A2=0.7/0.6; RfBl/B2=0.5/0.4).
A pre-sence of substances contained in Taxis baccata ex-               1. Kubis M., Kosatík A., Srp L., Švejda J., Mařík M.:
tract was not determined in the liver and kidney tissue nor               Prakt. Lék. 60, 720 (1980).
in the urine hydrolysate. Ehrlich reagent showed no colour             2. Kosatík A., Smysl B.: Scripta medica 51, 118 (1978).
reaction with taxin B / isotaxin B standard.                           3. Vaněrková H., Lysenková A.: Folia Fac. Med. Univ.
                                                                          Comenianae Bratisl, Suppl. 1990, 157.
Drägendorff reagent detection                                          4. Sinn L. E., Porterfield B. S., Porterfield J. F.: J. Foren-
                                                                          sic Sci. 36, 599 (1991).
     Substances contained in basic and acidic extracts of              5. Musshoff F., Jacob B., Fowinkel C., Daldrup T: Int. J.
yew react with the Drägendorff reagent. Some spots on the                 Legal Med. 106, 45 (1993).
chromatogram of basic extract of yew correspond with                   6. Beike J., Karger B., Meiners T., Brinkmann B.,
spots on the chromatogram of basic extract of stomach                     Köhler H.: Int. J. Legal Med. 117, 335 (2003).
content.. Because of multiple spots the chromatogram is                7. Frommherz L., Kintz P., Kijewski H., Köhler H.,
less clear. A presence of substances contained in Taxus                   Lehr M., Brinkmann B., Beike J.: Int. J. Legal Med.
baccata extract was not determined in the liver and kidney                120, 346 (2006).
tissue nor in the urine.



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P55
REDUCTIVE ACTIVATION OF ENVIRONMENTAL POLLUTANTS 3-NITROBENZANTHRONE
AND 2-NITROBENZANTHRONE


MARTINA SVOBODOVÁa, JANA ŠÍSTKOVÁa,                                                mented by the detection of specific DNA adducts formed
HELENA DRAČÍNSKÁa, JIŘÍ HUDEČEKa, PETR                                             in vitro as well as in vivo in rodents1,4−7. Most of the meta-
HODEKa, HEINZ H. SCHMEISERc, VOLKER                                                bolic activation of 3-NBA in vitro is attributable to human
M. ARLTb, EVA FREIc, MARIE STIBOROVÁa                                              and rat cytosolic NAD(P)H:quinone oxidoreductase
                                                                                   (NQO1), while human N,O-acetyltransferase (NAT),
a
  Department of Biochemistry, Faculty of Science, Charles                          NAT2, followed by NAT1, sulfotransferase (SULT),
University, Albertov 2030, 128 40 Prague 2, Czech Repub-                           SULT1A1 and, to a lesser extent, SULT1A2 are the major
lic, b Section of Molecular Carcinogenesis, Institute of                           phase II enzymes activating 3-NBA (ref.7). Microsomal
Cancer Research, Surrey SM2 5NG, United Kingdom,                                   NADPH:cytochrome P450 (CYP) reductase is also effec-
c
  Department of Molecular Toxicology, German Cancer                                tive in the activation of 3-NBA (ref.6), but in a model or-
Research Center, 69 120 Heidelberg, Germany                                        ganism, mice, 3-NBA is predominately activated by cyto-
stiborov@natur.cuni.cz, svobodova.mar@seznam.cz                                    solic nitroreductases such as NQO1 rather than micro-
                                                                                   somal NADPH:CYP reductase7 (fig. 1).
Key words: 3-nitrobenzanthrone, 2-nitrobenzanthrone,                                     While 3-ABA was suggested to be the main reductive
reduction, NAD(P)H:quinone oxidoreductase, HPLC                                    metabolite of 3-NBA (ref.7), the reactions of 3-NBA to 3-
                                                                                   ABA by enzymatic systems in vitro and in vivo has not
                                                                                   been investigated as yet. Reductive metabolism of 3-NBA
Introduction                                                                       is, therefore, investigated in this work. In addition, reduc-
                                                                                   tion of 3-NBA is compared with that of its isomer 2-NBA.
     3-Nitrobenzanthrone (3-nitro-7H-benz[de]anthracen-
-7-one, 3-NBA, fig. 1), occurs in diesel exhaust and in                            Materials and methods
airborne particulate matter1. 3-NBA might originate both
from incomplete combustion of fossil fuels and from reac-                               3-NBA, 2-NBA, 3-ABA and N-OH-ABA were syn-
tion of the parent aromatic hydrocarbon with nitrogen ox-                          thesized as described1,2,8. Incubations with human recom-
ides in the atmosphere. 3-NBA can spontaneously isomer-                            binant NQO1 or rabbit NADPH:CYP reductase, in a final
ize to 2-nitrobenzanthrone (2-nitro-7H-benz[de]anthracen-                          volume of 500 µl, consisted of 50 mM Tris-HCl buffer
-7-one, 2-NBA), which can become more than 70-fold                                 (pH 7.4), containing 0.4 % Tween 20, 1 mM NADPH,
higher in concentration in ambient air1,2. 3-Amino-                                from 5 to 50 µM 3-NBA or 2-NBA (in DMSO) and from
benzanthrone (3-ABA, fig. 1), suggested to be the main                             10 to 100 µg ml−1 of NQO1 or NADPH:CYP reductase. In
reductive metabolite of 3-NBA, has been found in urine                             incubations testing the time-dependent formation of 3-
samples of salt mine workers occupationally exposed to                             NBA-DNA adducts mediated by human recombinant
diesel emissions3, demonstrating that human exposure to                            NQO1 (20 µg ml−1), incubation times varied between 15
3-NBA in diesel emissions can be significant and is detect-                        and 60 minutes and 20 mM 3-NBA were used. The incu-
able. 3-NBA is carcinogenic in rats, causing lung tumours                          bation mixtures were extracted with ethyl acetate (2 ×
after intratracheal instillation4. It is also an exceptionally                     1 ml) and 5 µl of 1 mM phenacetine was added as an inter-
potent mutagen1. Its genotoxicity has been further docu-                           nal standard. The extracts were evaporated to dryness;

                                                                        H                      H                        H

                                                                        N O R                  N                        N

                                                                                                                                + DNA      dG-N2-ABA
                                                                                                                                          dG-C8-N-ABA
                                                                                                                                           dA-N6-ABA
                                                                 O                     O                          O


                                                       human NATs human SULTs
                                                                                                    plant HRP         human MPO
                                   rat and human         (NAT1,    (SULT1A1,
                                                                                                    bovine LPO        ovine PHS-1
                                liver cytosol (NQO1)     NAT2)      SULT1A2)
                                  rat and human                                               rat and human
                          NO2                                           NHOH                 liver microsomes                       NH2
                                 liver microsomes
                                       (POR)                                               (CYP1A1, CYP1A2)

                                in vivo in rats/mice                                       in vivo in rats/mice
                    O                                            O                                                          O
                  3-NBA                                              N-OH-ABA                                            3-ABA


Fig. 1. Pathways of metabolic activation and DNA adduct formation of 3-nitrobenzanthrone and 3-aminobenzanthrone; see text
for details. R = -COCH3 or -SO3H; dA-N6-ABA, 2-(2’-deoxyadenosin-N6-yl)-3-aminobenzanthrone; dG-N2-ABA, N-(2’-deoxyguanosin-
N2-yl)-3-aminobenzanthrone; dG-C8-N-ABA, N-(2’-deoxyguanosin-8-yl)-3-aminobenzanthrone


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Chem. Listy 101, s73−s310 (2007)                                                                                                                                                                                                 12. mezioborová česko-slovenská toxikologická konference


a                                                                                                                                                                                                                                b
    400                                                                                                                                                                                                                                 300
            mAU                                                                                                                                                                                WVL:254 nm                                                                                                                                                                                                                       WVL:254 nm
                                                                                                                                                                                                                                                                           mAU
                                                                                                                                               3 - 24.252
    300
                                                                                                                                                                                                                                                                                                                 1 - 4.767
                                                                                                                                                                                                                                                                                                                                   phenacetine
                                                                                             phenacetine                                                           3-NBA                                                                200                                                                                                                                 3 - 23.084
                         1 - 4.902                                                                                                                                                                                                                                                                                                                                                             3-NBA
    200
                                                                                                            3-ABA                                                                                                                                                                                                                          3-ABA
                                                                                                                                                                                                                                        100
    100

                                                                                        2 - 7.989                                                                                                                                                                                                                             2 - 7.763

                                                                                                                                                                                                        min                                                                                                                                                                                                                              min
    -50                                                                                                                                                                                                                                 -50
          0.0           5.0                                                                  10.0             15.0              20.0           25.0              30.0        35.0       40.0                45.0                                       0.0                                                      5.0                10.0           15.0           20.0           25.0             30.0      35.0        40.0                    45.0




Fig. 2. HPLC of incubations of 3-NBA with NQO1 (a) and NADPH:cytochrome P450 reductase (b)




a                                                                                                                                                                                                                                b
      200                                                                                                                                                                                                                         300
                  mAU                                                                                                                                                                               WVL:254 nm                                        mAU                                                                                                                                                                  W VL:254 nm
                                                      1 - 4.921                                                                                                                                                                                                                                            1 - 4.783
      150
                                                                                                    phenacetine                                                                                                                   200                                                                                        phenacetine                                                      2-NBA
                                                                                                                                                                           2-NBA
      100
                                                                                                                                                                                                                                  100

          50
                                                                                                                                                                                                                                                                                                                                                                            2 - 24.258
                                                                                                                                                      3 - 25.422

                                                                                                                                                                                                                                                                                                                                                                                                                                   min
                                                                                                                                                                                                              min                 -50
          -20                                                                                                                                                                                                                           0.0                                                               5.0                  10.0            15.0           20.0          25.0              30.0      35.0        40.0                 45.0
                0.0                5.0                                                          10.0             15.0              20.0           25.0              30.0         35.0        40.0                45.0




Fig. 3. HPLC of incubations of 2-NBA with NQO1 (a) and NADPH:cytochrome P450 reductase (b)




                                                                                        10
                                                                                                                     3 -A B A
                                                                                                                     3 -N B A
                                                                                                                                                                                                                               duction (fig. 4), dependence of converted 3-NBA and pro-
                                                                                                                                                                                                                               duced 3-ABA on NQO1 (fig. 5) and 3-NBA concentra-
                              Amount of transformed 3-NBA

                                                            and gnerated 3-ABA [nmol]




                                                                                         8



                                                                                         6
                                                                                                                                                                                                                               tions (fig. 6). A time-dependent decrease in 3-NBA con-
                                                                                         4
                                                                                                                                                                                                                               centrations in incubations correlated with an increase in 3-
                                                                                         2
                                                                                                                                                                                                                               ABA formation (fig. 4). Reduction of 3-NBA to 3-ABA by
                                                                                         0
                                                                                                                                                                                                                               human NQO1 in the presence of NADPH exhibits the
                                                                                                       10               20                30                40
                                                                                                                                  T im e o f in c u b a tio n [m in ]
                                                                                                                                                                            50          60
                                                                                                                                                                                                                               Michaelis-Menten kinetics (data not shown). The values of
                                                                                                                                                                                                                               Michaelis constant Km of human NQO1, measured for 3-
Fig. 4. Time-dependence of 3-NBA reduction by NQO1                                                                                                                                                                             NBA reduction and 3-ABA production, were 10.3 and
                                                                                                                                                                                                                               7.6 µM, respectively.
                                                                                                                                                                                                                                    In order to examine the molecular basis of the potent
                                                                                                                                                                                                                               reduction of 3-NBA by human NQO1, the binding of 3-
residues dissolved in 30 µl of methanol, and subjected to                                                                                                                                                                      NBA to the active centre of NQO1 was modeled (fig. 7).
RP-HPLC to evaluate the amounts of products of 3-NBA                                                                                                                                                                           The model structures for the human NQO1-3-NBA-
and 2-NBA reduction. HPLC was under isocratic condi-                                                                                                                                                                           complex were calculated. It is evident that 3-NBA fits well
tions of 70 % methanol, with a flow rate of 0.6 ml min−1.                                                                                                                                                                      into the active site of human and rat NQO1, being bound
The modeling of the binding of 3-NBA to the active site of                                                                                                                                                                     near the isoalloxazine ring of the flavin prosthetic group of
NQO1 was performed with the program Autodock 3.0.3.                                                                                                                                                                            the enzyme. This allows an electron transfer during the
and Sybyl 6.6.5 (Tripos GmbH, Germany) by the proce-                                                                                                                                                                           reduction of 3-NBA. The value of the apparent dissocia-
dure described7.                                                                                                                                                                                                               tion constant for the human NQO1-3-NBA-complex was
                                                                                                                                                                                                                               calculated to be 0.26 µM, respectively.
Results and discussion

      Human NQO1 metabolizes 3-NBA to one major                                                                                                                                                                                                                                                      10                                                        3 -A B A

product identified as its reductive metabolite found in
                                                                                                                                                                                                                                                                                                                                                               3 -N B A
                                                                                                                                                                                                                                                                                                      8


urine samples of humans exposed to diesel emissions3, 3-
                                                                                                                                                                                                                                          Amount of transformed 3-NBA




                                                                                                                                                                                                                                                                                                      6
                                                                                                                                                                                                                                                                        and generated 3-ABA [nmol]




ABA. Both compounds were separated by HPLC as two
                                                                                                                                                                                                                                                                                                      4




distinguish peaks (fig. 2). NQO1 is the more effective
enzyme to form this product than NADPH:CYP reductase
(fig. 2a,b). In contrast to 3-NBA, no 2-NBA metabolites
were generated by both enzymatic systems, which indicate                                                                                                                                                                                                                                              0
                                                                                                                                                                                                                                                                                                            0                             10                     20                      30                    40             100

that this compound is a much worse substrate (if any) for                                                                                                                                                                                                                                                                                             C o n c e n t r a t io n o f N Q O 1 [µ g /m l]


these enzymes than 3-NBA (fig. 3a,b). The metabolism of
3-NBA by human recombinant NQO1 was studied in de-                                                                                                                                                                             Fig. 5. Dependence of 3-NBA reduction by NQO1 on the en-
tail. We investigated the time-dependence of 3-NBA re-                                                                                                                                                                         zyme concentration


                                                                                                                                                                                                                        s278
Chem. Listy 101, s73−s310 (2007)                                                                                                                     12. mezioborová česko-slovenská toxikologická konference


                                                                  8
                                                                               3 -A B A
                                                                  7            3 -N B A
       Amount of transformed 3-NBA
                                     and generated 3-ABA [nmol]




                                                                  6

                                                                  5

                                                                  4

                                                                  3




                                                                  1




                                                                  0
                                                                      0    5       10                15              20                50

                                                                                          C o n c e n tr a tio n o f 3 -N B A [µ M ]




Fig. 6. Dependence of 3-NBA reduction by NQO1 on 3-NBA                                                                                             Fig. 7. 3-NBA docked to the active site of human NQO1
concentration




Conclusion                                                                                                                                         REFERENCES

     The results demonstrate for the first time that 3-NBA                                                                                          1. Arlt V. M.: Mutagenesis 20, 399 (2005).
is reduced by NQO1 and NADPH:CYP reductase to 3-                                                                                                    2. Nagy E., Johansson C., Zeisig M., Möller L.: J. Chro-
ABA. The results also explain a strong mutagenicity and                                                                                                matogr., B 827, 94 (2005).
carcinogenicity of 3-NBA in contrast to 2-NBA. Much                                                                                                 3. Seidel A., Dahmann D., Krekeler H., Jacob J.: Int. J.
higher mutagenicity and carcinogenicity of 3-NBA evolve                                                                                                Hyg. Environ. Health 204, 333 (2002).
from its potential to be easily reduced to reactive species                                                                                         4. Nagy E., Zeisig M., Kawamura K., Hisumatsu Y.,
binding to DNA.                                                                                                                                        Sugeta A., Adachi S., Moller L.: Carcinogenesis 26,
                                                                                                                                                       1821 (2005).
    Supported by grants 303/05/2195, MSM 0021620808                                                                                                 5. Arlt V. M., Bieler C. A., Mier W., Wiessler M.,
and 1M4635608802.                                                                                                                                      Schmeiser H. H.: Int. J. Cancer 93, 450 (2001).
                                                                                                                                                    6. Arlt V. M., Stiborova M., Hewer A., Schmeiser H. H.,
Abbreviations                                                                                                                                          Phillips D. H.: Cancer Res. 63, 2752 (2003).
                                                                                                                                                    7. Arlt V. M., Stiborova M., Henderson C. .J., Osborne
CYP                                                                       cytochrome P450                                                              M. R., Bieler C.A., Frei E., Martinek V., Sopko B.,
NQO1                                                                      NAD(P)H:quinone oxidoreductase                                               Wolf C. R., Schmeiser H. H., Phillips D. H.: Cancer
NATs                                                                      N,O-acetyltransferases                                                       Res. 65, 2644 (2005).
SULTs                                                                     sulfotransferases
N-OH-ABA                                                                  N-hydroxy-3-aminobenzanthrone




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