NCABR Rx for Science Literacy The What, Where, How and Why of Health Science Research November 10, 2011 Michael C. Humble, PhD Program Administrator Division of Extramural Research and Training (DERT) National Institute of Environmental Health Science (NIEHS) National Institutes of Health (NIH) Dept of Health & Human Services (DHHS) The National Institute of Environmental Health Sciences The National Institutes of Health NIH consists of 27 Institutes and Centers NHLBI NINR OD NCCAM NIEHS NCI NIAMS CIT NIDA NEI NIMH CC NIDDK NLM NINDS NHGRI NIDCR NCMHD NIBIB NIA NIDCD NIAAA NICHD NIAID FIC CSR NCRR NIGMS = Extramural only NIAID Hamilton, MT NIA, NIDA Baltimore, MD NIDDK NIH NIH Phoenix, AZ Bethesda, MD Bethesda, MD NIEHS NIEHS Raleigh/Durham, NC Raleigh/Durham, NC Rx for Science Literacy The What, Where, How and Why of Health Science Research NCABR Contents Unit 1 – Biomedical Research Unit 2 – Care and Use of Animals in Biomedical Research Unit 3 – Challenges to Biomedical Research Unit 4 – Other Issues in Science Unit 1 – Biomedical Research Contents Chapter 1 - What is Science Chapter 2 - What is Biomedical Research Chapter 3 - Biomedical Research Methods Chapter 4 - Benefits of Biomedical Research What is Science? Unit I-1: What is Science? "Science is a continuous stream of ideas that are constantly being reshaped, added to, subtracted from and built upon." Science is always evolving. What is Science? (Continued) Basic science is the foundation of biomedical research. Introducing the concepts of critical thinking and inquiry-based learning will provide students with the tools they need to solve problems. These tools are important whether students eventually pursue careers in science or vote on public policy issues based on scientific and technological research advances. How to Think Like a Scientist • Anyone can think like a scientist! • BE CURIOUS — look around and ask questions about things! Why is the sky blue? How do amoebas eat? How can I get energy from the sun? • BE SKEPTICAL — don't always believe the first thing you hear. Look for MANY possible explanations, see which facts support which explanations, and then pick the best one. Do you believe in UFOs? Bigfoot? • BE FLEXIBLE — even after you've found one explanation, keep looking! Sometimes you can find an even better one later. Don't be afraid to give up old ideas for new ones, as long as they’ve passed the skepticism test! • These three brain exercises add up to what is called CRITICAL THINKING...what scientists do all the time! How to Act Like a Scientist Once you're in the habit of thinking like a scientist, it's a simple matter to APPLY it to real life. You can use the same logical four-step approach that scientists do -- the SCIENTIFIC METHOD. OBSERVATION — carefully watching something around us — in the environment, in animals, or in ourselves-in an objective way. HYPOTHESIS — an educated guess explaining what you are observing, or how to change what you are observing. EXPERIMENT — testing your hypothesis by designing and carrying out an experiment. Part of designing an experiment is determining what measurements, or data, you will take to compare the experimental and control groups. The measurements you choose should be repeatable by someone else as well as relevant as a predictor. t's important to gather enough data and have a sufficient number of subjects in each group. The scientist often uses a branch of mathematics called statistics to calculate whether the difference between the groups was significant. CONCLUSION — judging on the basis of your experiment if your hypothesis is right or wrong. Your conclusion usually falls into one of two categories: CORRELATION — two things that tend to happen together. CAUSE-EFFECT — one thing or event actually causes the other to happen. Correlation can be established through observation. You just need to notice two things always seem to occur together. Cause-effect is tougher to establish. Once you've noticed two things occurring, you need to TEST to see if they are actually linked to each other. Cause-effect is a better predictor than correlation. Activity – How Observant are You? Without looking, answer the following questions: 1. Without looking down, what color socks are you wearing today? 2. When you fold your arms, which arm do you put on top? 3. When you clasp your hands in front of you, which thumb is on top? 4. Which direction does Lincoln face on a penny? 5. How many sides does a pencil have? 6. What color is the top light on a traffic light? 7. How many sides does a stop sign have? 8. In the kitchen or bathroom sink, which side of the faucet is the hot water knob on? 9. Without looking back at your neighbor, what color shirt are they wearing? 10. What color was the pen in my pocket? Great "Truths" At various times in history, scientist "knew" these things: 4,000 B.C. The moon is eaten once each month by a large invisible beast. 1400 A.D. Diseases are caused by evil spirits that inhabit a body. 1500 Flies develop spontaneously from rotten meat. 1800 Tyrannosaurus Rex walked vertically and dragged its tail. 1900 The Apatosaurus and brontosaurus are two different dinosaurs. 1970 Saturn is the only planet with rings around it. 1980 Eating eggs makes your cholesterol levels rise. 1985 Pandas are bears. 1995 Human Genome Project begins and estimates that human chromosomes carry about 100,000 genes. 1999 The Y2K Bug will shut the world down Great "Truths" These are our explanations for Great "Truths" today: • The moon darkens each month because the angle between the Earth, Moon and Sun changes. • Diseases are caused by microscopic agents ("germs"), such as bacteria, viruses, protozoa and fungi. • Flies lay their eggs in rotten meat and hatch. • Tyrannosaurus Rex leaned forward and its tail balanced it, but it didn't touch the ground. • Apatosaurus and brontosaurus are the same species. • Uranus and Jupiter also have rings. • Some people's cholesterol levels stay the same or go down even if they eat eggs. • Pandas are genetically between bears and raccoons. • The human genome has at most 25,000 genes — and 95 percent of our genome is the same as the chimpanzee. • Great efforts to prevent the Y2K "bug" seemed to work, since very few computer systems crashed on January 1, 2000. What do we know today that will make scientists 500 years from now laugh? Activity – What is a Scientist? Make a list of adjectives and/or nouns that come to mind when you think of science or scientists. Draw a picture of a scientist. Activity – What is a Scientist? Typical Responses: smart white lab coats eccentric chemicals wild looking hair test tubes male microscopes glasses rockets old nerdy Activity – What is a Scientist? Activity – What is a Scientist? Follow-up Questions: Can women be scientists? Can black or Hispanic people be scientists? Do scientists have babies? Do some scientists have pets? Go on vacation? Watch TV? Go to the movies? Do scientists always work indoors? Do scientists always work during the daytime? Activity – Think Creatively A scientist needs to think creatively and see new solutions to old problems. Activity – Think Creatively How would your students solve the following problems? 1. You have five pieces of tissue paper in the palm of your hand. You need to drop them one at a time into a bowl, but you can only use that one hand ... HOW COULD YOU DO IT? 2. You have a sheet of newspaper. Can you place it on the floor in such a way that you and a friend can both stand on it, but no matter how hard you try, your friend cannot touch you? 3. You accidentally drop a ping pong ball into a hole in the ground. The hole is too deep for you to reach in and grab it. How could you get it out? 4. Can you tip a glass of water over without spilling it? 5. Can you empty a glass of water without touching it or the table it's on? Unit I-2: What is Biomedical Research? Biomedical research is the area of science devoted to: the study of the processes of life; the prevention and treatment of disease; and the genetic, lifestyle and environmental factors related to disease and health. Biomedical (health science) research can be divided into three highly interdependent yet broad categories: 1) basic research 2) applied research 3) clinical research Basic Research • Basic research is research conducted to increase fundamental knowledge and understanding of the physical, chemical and functional mechanisms of life processes and disease. • It is not directed to solving any particular biomedical problem in humans or animals. • This type of research often involves observing, describing, measuring and manipulating natural systems. • It provides the building blocks upon which other types of research are based. Applied Research • Applied research is directed toward specific objectives, such as development of a new drug, treatment or surgical procedure. • It involves the application of existing knowledge, much of which is obtained through basic research, to a specific biomedical problem. • Applied research can be conducted with animals, with non- animal methods such as computer models or tissue cultures, and with humans. • Behind most every health advance lies years of applied research. Clinical Research • Information gained through basic and applied research often leads to potential treatments to prevent or cure disease. • Once all other forms of study and testing have taken place, scientists look to clinical research to test potential drugs and treatments in humans. • This research builds upon that done in the basic and applied research stages. However, clinical research is not always the end. Often, it leads back to the lab, where further research is done. It is this interdependence that at times makes science seem so complex. • Clinical research takes place in a hospital or other clinical setting for health care and directly applies to the prevention, diagnosis or treatment of a specific disease in the individual or group of individuals, or to the rehabilitation of the patient. • Clinical research includes a broad variety of activities, and there are many areas of study. These areas include human clinical trials, psycho social and behavioral research, and disease control research. Unit I-3: Biomedical Research Methods • Biomedical research is a complex process. Rather than a simple "lab-to-patient" scenario, it employs a wide variety of methods to develop new treatments and cures. This section presents a brief description of some of the major types of methods being used today. • While each of the methods provides valuable information, they are highly interdependent. As a result, researchers today must cooperate more than ever before. The lessons in this section are designed to introduce some of the basic methods of biomedical research and to provide some hands-on activities for student research. Biomedical Research Methods • Chemical • Non-human animal models • Mathematical • Clinical trials • Computer Simulations • Epidemiological Studies • In Vitro Chemical Methods • Often used when developing vaccines, prescription drugs and vitamins • Analytical chemistry tests • Antibody tests • Can detect substances and measure potency • Pros - can simplify, reduce number of animals needed • Cons - often too simple Mathematical and Computer Methods • Has been used to test a structure’s “activity” within an organism • Predict biological response • Analyze chemical structure of new drugs • Pros - Increase speed and efficiency, can extrapolate data, use less animals • Cons - Can’t generate data- only process information given, hardware very expensive In Vitro Methods • “In glass” - cell cultures – artificial environment • Pros - Can study single effect without interference, less expensive, less time. • Cons - Difficult to maintain cultures, can’t duplicate complex reactions Non-human Methods • Uses animals as models for humans (in vivo) • Pros - ethical replacement for humans, provides whole biological system • Cons - controversy using animals, expensive, animals aren’t identical to humans Human Clinical Trials • Actual use of drug or treatment on humans • Pros - Gives precise data on drug or treatments effectiveness • Cons - Lengthy, some risk for volunteers Human Clinical Studies Epidemiological Studies • Another type of human study • Examine the occurrence and distribution of disease in a population • Pros - Can study effect of humans exposed to disease • Cons - Difficult to detect cause and effect, hard to have control groups Activity – Itchy Sleep Disease • There is a new disease called "itchy sleep" that affects children. • The "itchy sleep" disease causes children to become very sleepy but as they try to fall asleep, they become itchy all over. • Scientists have discovered that mice can catch the disease as well. Activity – Itchy Sleep Disease Topics for Discussion: 1. What was the same about the groups? 2. What was the purpose of giving different medicines? 3. Why didn't the "mice" in the control group receive any medicine? 4. How did the scientists know their mice got better? (Talk about the importance of observation in the research process.) Human Clinical Trials Human clinical trials are a very important component of the biomedical research process and are most often used in developing prescription drugs. Even after a promising new drug has undergone extensive laboratory research and testing, scientists still need actual human data from controlled studies to answer two key questions: 1. Is the drug biologically active in humans? 2. Is it safe in humans? Human Clinical Trials There are three major phases of clinical trials that begin after a pharmaceutical firm files an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA). In the IND, a pharmaceutical firm shows the results of laboratory testing and explains how the drug is made. In Phase I clinical trials, researchers determine a drug's interaction with the human system, including how it is absorbed, distributed, metabolized and excreted, and the likely duration of its therapeutic effect. This phase involves a small number of healthy volunteers and takes approximately one year. Human Clinical Trials Phase II trials use controlled tests that help determine a drug's effectiveness. These studies involve 100 to 300 volunteer patients. Simultaneous animal and human tests are also conducted at this stage as researchers continue to assess the safety of the drug. This phase takes approximately two years. Phase III trials are conducted to confirm the results of earlier efficacy tests and further identify any adverse reactions. Clinical testing at this point is extensive, involving 1,000 to 3,000 volunteer patients in medical clinics and hospitals. This phase takes approximately three years. Human Clinical Trials After human clinical trials are completed, firms file a New Drug Application (NDA) with the FDA. The NDA is a comprehensive statement of the information on: •drug structure •the scientific rationale and purpose of the drug therapy •pre-clinical animal and other laboratory study results •all human clinical testing results •drug formulation and production details •and the company's proposed labeling This takes approximately two and one-half years to complete. Human Clinical Trials Activity – Cholera and the Scientific Method Students act as epidemiologists and use the scientific method to track the contamination source. Activity – You Choose the Test! Unit I-4: Benefits of Biomedical Research • Biomedical research has led to tremendous advances in quality of life, therapeutic drugs, diagnostic tools, vaccine production, and workplace safety. • Everyone, in some way, has been touched by the results. Activity – Did You or Will You Ever? 1. Drink tap water? 2. Have a dog? 3. Have a cat? 4. Fertilize your lawn? 5. Drink milk? 6. Eat a hamburger? 7. Call Poison Control? 8. Receive a vaccination? 9. Take an antibiotic for an infection such as strep throat or an ear infection? 10. Eat eggs? 11. Observe an endangered species at a zoo? 12. Eat bacon or North Carolina barbecue? 13. See a guide dog? 14. Have a relative over the age of 45? 15. Take medicine? 16. Know anyone with diabetes who needs to take insulin? Activity – Did You or Will You Ever? Count the number of times you answered yes. 12- 14 You and biomedical research are inseparable 9 - 11 You are affected 7-8 Take it or leave it 5-6 Would not miss it 0-4 Bio-what? Activity – Did You or Will You Ever? 1. Drink tap water? Chemicals and agricultural runoff add to contaminants in our water supply. Biomedical research continues to identify and to study what these contaminants might do to human health. 2. Have a dog? A vaccine for rabies in dogs was developed in the 1880s by a biomedical researcher, Louis Pasteur. 3. Have a cat? A vaccine for cats has been developed for the fatal feline leukemia virus. 4. Fertilize your lawn? Research continues to expand knowledge about the health effects of agricultural products for those who manufacture these chemicals as well as consumers who use them. 5. Drink milk? Milk is fortified with vitamin D, which research has shown is necessary for proper absorption of calcium salts and their deposition (placement) in bone. 6. Eat a hamburger? Vaccines for cattle diseases, such as hoof-and-mouth disease, were developed by scientists. 7. Call Poison Control? Information is provided to those calling about the potentially toxic effects of such things as household products, fertilizers, etc. and, if appropriate, further treatment is recommended. 8. Receive a vaccination? North Carolina requires children to be vaccinated against several diseases before school entry. These vaccines are the result of biomedical research. They include polio, diphtheria (whooping cough), measles, mumps and rubella. Activity – Did You or Will You Ever? 9. Take an antibiotic for an infection such as strep throat or an ear infection? Alexander Fleming's studies provided evidence that penicillin was a potent antibacterial agent. 10. Eat eggs? Vaccines for a number of chicken diseases (no, not chicken pox) have been developed thanks to biomedical researchers. 11. Observe an endangered species at a zoo? Embryo transfer techniques are being used to increase populations of endangered species. 12. Eat bacon or North Carolina barbecue? A vaccine for "scours," a disease that kills piglets, was made possible by genetic engineering. 13. See a guide dog? Behavioral studies made possible the training of dogs used to aid the blind and deaf. 14. Have a relative over the age of 45? At the turn of the century the average life span was about 45 years. Thanks to improved sanitation, nutrition and biomedical research, the average life expectancy has increased to about 73 years of age. 15. Take medicine? All prescription and nonprescription medicines sold in the United States are first tested in at least two species of animals. 16. Know anyone with diabetes who needs to take insulin? Insulin isolated from animal pancreas (the organ that makes insulin for humans and other mammals) was used for decades to keep people with diabetes alive. Now, thanks to biomedical research and biotechnology techniques, most people with diabetics take insulin produced by cells that carry the human insulin gene. These cells are grown in giant vats on a commercial scale. What Difference Has Biomedical Research Made to Human Health? • There isn't a day that goes by that medical research doesn't affect our lives. • And in many cases, it is our own awareness that has made the difference. • The public's awareness of healthy lifestyle choices has helped reduce mortality rates and has become the best medicine in preventing needless disease and disabilities. • Think about the childhood diseases generations of children won't have because of vaccines. Measles — mumps — chicken pox — polio. Vaccines save millions of lives. • For the most part we don't think about medical research until we're sick. Then we want the cure, in a bottle, at the drug store, and for a low price. However, that will only happen through medical research, and that requires an investment — an investment that saves lives and money. What Difference Has Biomedical Research Made to Human Health? • Treatments for: – Heart Disease – Cancer – Diabetes • Protective Vaccines – Polio Vaccine – Chicken Pox – Hepatitis • Development of Treatments like: – Fluoride – Penicillin and Other Antibiotics – Cyclosporine and Other Anti-Rejectiton Drugs – Monoclonal Antibodies • Surgical and Other Artificial Devices – Angioplasty – Organ Transplantation • Heart • Kidney • Liver • Corneas • Bone Marrow What Difference Has Biomedical Research Made to Animal Health? Benefits for Animals: • Artificial joints for dogs with hip displace • Cancer treatments • Embryo transfer techniques to improve breeding • Chemotherapy • Feline leukemia research • Genetic research for inherited diseases in pedigreed animals • Heart disease treatment • Nutrition research for pet food • Orthopedic surgery & rehabilitation techniques for horses • Tooth and gum disease research • Treatment for parasites (heartworm, hookworm) • Vaccines for livestock and poultry • Vaccines for pet diseases (rabies, distemper, parvo virus, infectious hepatitis) • Antibiotics • Anesthesia Unit 2 – Care and Use of Animals in Biomedical Research Contents Chapter 1 – Student Surveys Chapter 2 – Why Use Animals Chapter 3 – Advances Based on Animal Research Chapter 4 – Numbers and Species of Animals Used Chapter 5 – Care of Research Animals Unit II-1: Student Surveys Surveys of young people have shown a lack of understanding about the tremendous care that animal care technicians and scientists deliver to animals used in research. This chapter is designed to increase young people's awareness of the care and treatment such animals receive. Unit II-2: Why Use Animals? In research, animals are used to learn more about biological systems and the illnesses that afflict human beings and other animals. They serve as surrogates for humans in obtaining information that cannot be gained in any other way. The reference sheets in this chapter provide information on animal models used for biomedical research. Most Commonly Used Animal Models Animal System/Condition Why Is It Studied? Cats Auditory Like man, cats have a very well-developed hearing system and brain mechanisms for hearing. They can be trained to respond to many behavioral cues given through auditory stimuli. Cats also experience naturally occurring hearing defects and are susceptible to environmentally induced defects, as is man. Primates Immune Primates possess striking immunological similarities to humans. They are susceptible to similar diseases and often react to the same infectious agents as humans. Dogs Cardiovascular A dog's cardiovascular system is structured quite similarly to man. They suffer from many inherited cardiovascular defects that affect man. Because they possess inherited defects nearly identical to those seen in humans, hematology, the study of the blood, is also practiced using dogs. Dogs Endocrine Dogs naturally experience diabetes, as do humans. Diabetes can also be easily induced in dogs to aid research. In addition, dogs share other diabetes- induced deficits, such as glaucoma, that occur in man. Mice Aging Mice age 30 times more rapidly than humans, with several body systems declining with age in the same manner as those in humans. Genetic composition and environmental conditions can be precisely and easily duplicated and controlled, a vital consideration in interpreting data. Rats Aging Rats are available in a number of purpose-bred strains and have been the focus of intensive physiological and biochemical research. Rats show major, spontaneously developing, age-related damage in most major systems of the body that are commonly seen in humans. However, in rats these deficits occur faster and are easily studied during a rats lifetime. Unit II-3: Advances Based on Animal Research Virtually all major medical advances have involved research with animals. Animal models provide a ready mechanism for the screening and evaluation of new drugs prior to human clinical trials. Researchers must discover not only what the drug does to the body, but also what the body does to the drug. The information provided in this chapter looks at some major biomedical advances and the animal models that were used. Without Animal Research… • Polio would kill or cripple thousands of unvaccinated children and adults this year. • Some of the 50 to 60 percent of newborns who develop jaundice each year would develop cerebral palsy, now preventable through phototherapy. • Most of the nation's 580,000 insulin-dependent diabetics wouldn't be insulin dependent. They would be dead. • The U.S. would experience 1.5 million cases of rubella... over 400 times the current annual incidence of the disease. • 65 million Americans would be at risk of death from heart attack, stroke or kidney failure for lack of medication to control their high blood pressure. • The 200,000 arthritics who each year receive hip replacements would be confined to wheelchairs. • Without cataract surgery, more than a million people would lose their vision in at least one eye. Eighty percent of all persons 65 or older will need cataract surgery in at least one eye. • Death would be a certainty for the more than 16,000 patients in the United States who receive kidney transplants each year. An additional 63,000 patients are in need of this operation. • There would be no kidney dialysis to extend the lives of the more than 453,000 victims of end-stage renal disease. • Chemotherapy would not be able to save the children who now survive acute lymphocytic leukemia. • Hundreds of thousands of people disabled by stroke and head injury would not benefit from rehabilitation techniques developed in animals. • New surgical procedures to repair congenital heart defects would have to be abandoned or tried for the first time on children. • A cure for diabetes would be beyond reach. • The number and variety of medications that keep HIV infections under control would not be available. • There would be no hope of finding a safe and effective vaccine against AIDS. • Development of techniques that may help restore function to paralyzed victims of spinal cord injuries would not continue. • The 30,000 young Americans with cystic fibrosis would have little hope of a normal lifespan. • The 350,000 people with multiple sclerosis, including 4,500 in North Carolina, would lose the promise of new treatments for the symptoms of this degenerative disease. • Thousands of schizophrenics would be institutionalized because of lack of understanding of the disease and its treatment. • Methods to prevent many cancers would never be found, since theories about genetic and environmental causative factors cannot be tested in humans. • Improvement of hearing through electronic stimulation of the inner ear might never benefit any of the 20 million hearing-impaired Americans. • It would be too dangerous to test breakthrough products such as artificial blood, which show promise for saving the lives of critically injured accident victims. • Researchers would be unable to clarify the cause of Alzheimer's disease. Without that knowledge, the prognosis for the 4 million Alzheimer's victims would remain bleak. Almost 58,000 North Carolinians are affected by Alzheimer's disease. • The development of urgently needed new drugs to treat heart disease, cancer and a host of other diseases would be severely curtailed. Activity – Human and Animal Health Has Come A Long Way Students construct a timeline showing biomedical achievements for a specific time period. Unit II-4: Numbers and Species of Animals Used Most people are not aware that more than 90 percent of the animals used in biomedical research are rats and mice. These reference sheets and the lesson plan contained in this chapter provide accurate numbers of the various types of animal models used in biomedical research. Did you know that: • Ninety-five percent of all animals used in medical research are rats, mice or other rodents specifically bred for research. • Valid and useful scientific findings are obtainable only when research animals are healthy and protected from undue stress. • Federal regulations prohibit both animal abuse and the use of sick, injured or distressed animals as research subjects. • The majority of animal studies use medical techniques similar to those used on humans. They involve little or no pain for the animals. • Humans are also often used as research subjects. • Research animals are carefully selected to ensure that only the number and species essential to each research project is used. • Most research animals are bred specifically for that purpose. What Kinds of Animals are used for Research Primates (Monkeys) Less than 0.5% Cats Less than 0.5% Dogs Less than 0.5% Rabbits, Guinea Pigs, Hamsters Less than 3.3% Rats & Mice More than 90% Unit 3 – Challenges to Biomedical Research Contents Chapter 1 – Critical Thinking Chapter 2 – Animal Research: Issues and Answers Chapter 3 – Transgenic Animals Chapter 4 – Therapeutic vs. Reproductive Cloning: Scientific Realities, Public Controversy Unit III-3: Transgenic Animals transgenic animals -- species that carry one or more genes from another species Unit III-3: Transgenic Animals scientists around the world can now create customized transgenic animals for their own research Many species are used, including sheep, goats, cows, chickens, pigs, mice, rabbits, rats, chickens, and fish Unit III-3: Transgenic Animals Although transgenic techniques are applicable to many species, mice are more commonly used for research than other transgenic animals for several reasons: • They reproduce quickly. • They are small animals and therefore easily housed. • Their genetic makeup is better understood than other mammals. • Their lifespan is 2-3 years, allowing researchers to follow disease processes from infancy to old age over a relatively short time. • Moreover, numerous strains of inbred mice -- where all members of one strain have exactly the same genetic makeup - - are available commercially. Making a Transgenic Mouse Model for Leukemia What is leukemia? Leukemia – a cancer involving blood cells RBCs carry oxygen to tissues White blood cells help fight infection throughout the body Platelets help form blood clots that control bleeding In people with leukemia, the bone marrow produces abnormal white blood cells. At first, leukemia cells function almost normally. In time, they may crowd out normal white blood cells, red blood cells, and platelets, making it hard for blood to do its work. Gene Structure Promoter Coding Region Termination Sequence http://images.clinicaltools.com/ How to Produce a Transgenic Animal The first step in producing a transgenic animal is to construct the transgene, which is the DNA to be transferred into the animal. How to Produce a Transgenic Animal What should the transgene do? To model leukemia, we want to create and add a gene that will cause the bone marrow to make too many white blood cells Promoter: should enable gene expression only in the tissue of interest, the bone marrow example: globin gene promoter Gene: should be a gene that causes cell proliferation example: ras oncogene Termination Sequence: something unique that can be “traced,” perhaps a viral sequence that would not normally be found in the organism example: SV-40 polyadenylation sequence zeta globin promoter v-Ha-ras SV40 Poly A Tg.AC Transgene zeta globin promoter v-Ha-ras SV40 Poly A EcoR1 HincII/BamH1 Xba1 EcoR1 Mutations in v-Ha-ras Codon 12 Codon 59 glycine arginine alanine threonine How to Produce a Transgenic Animal For a transgene to be incorporated into all of the cells of an organism, it must be introduced at the single-cell embryo stage. The following method is used to produce transgenic mice: • Female mice are given hormones so that they superovulate (produce a large number of eggs). • They are mated. • Hours later, single-cell embryos are removed from the females. • Using a microscope and a microinjecter, scientists inject each embryo with copies of the transgene. • These eggs are then transferred to surrogate mothers of the same strain who have been treated with hormones so that the eggs can implant and grow. How to Produce a Transgenic Animal Scientists can determine if the mice in the litter have the gene by analyzing a small piece of each mouse’s tail when it is eight to 10 days old, using a technique called polymerise chain reaction (PCR). Millions of copies of a gene can be made in a few hours. Mice that carry the transgene are observed for any indication that the presence of the transgene has affected the animal. Characteristics of the Tg.AC Transgenic Mouse Model • location of transgene – insertion on chromosome 11 – 10+ copies • mice were not overly susceptible to leukemia • mice were susceptible to skin cancer • transgene expression is inducible in the skin Potential Use of the Tg.AC Transgenic Mouse Model • opportunity to identify the molecular mechanisms that associate with the biology of the induced tumor response • chemical evaluation for human risk assessment Unit 4 – Other Issues in Science Contents Chapter 1 – Careers in Biosciences Chapter 2 – Genetics Primer I fully realize that I have not succeeded in answering all of your questions … Indeed; I feel that we have not answered any of them completely. The answers we have found only serve to raise a new set of questions, which only lead to more problems, some of which we weren’t even aware were problems. To sum it all up … In some ways I feel we are as confused as ever, but I believe we are confused on a higher level, and about more important things.
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