FAQ: SCIENCE

What are the different ways animals are used in biomedical research?

Has the number of animals used in biomedical research increased or decreased over the years?

Where do laboratories obtain the animals they use for biomedical research?

Isn't animal research the most effective way to test new medicines and surgical instruments and procedures?

How does animal research sidetrack medical progress and compromise human health?

Aren't people and animals enough alike to make animals adequate test subjects for humans in the laboratory?

Why are rodents inadequate models for human disease?

Can the results of studies from different species within the same genus give different results?

Wouldn't medical progress come to a grinding halt if we stopped experimenting on animals?

Has animal research ever contributed to medical knowledge?

Don't surgeons train on animals before operating on humans?

If animal research is so ineffective, why do scientists continue to do it?

What about the claim by animal researchers that you must animal test in order to observe a "whole system" model?

If we didn’t test on animals, how could we find cures for human diseases?

Isn't the use of animals necessary if we are to find a cure for AIDS?

Isn't the use of animals necessary if we are to find a cure for cancer?

Isn't the use of animals necessary if we are to find a cure for diabetes?

Is it true that the availability of penicillin was delayed as a result of animal testing?

How could we have discovered a vaccine for polio without using animals?

How do animal studies impact on the drug development process?

How would we determine the safety of drugs for human use without first testing them on animals?

If you want to avoid subjecting human patients to unexpected side effects, why not conduct more animal tests during the development process?

How can we know what medications will cause birth defects without first testing them on animals?

Are there any examples of drugs that have caused birth defects in humans, but not in animals?

What are some examples of drugs that have caused birth defects in animals, but not in humans?

What are some examples of pharmaceutical drugs that caused serious side effects not revealed in animal studies?

What are some examples of cases where animal studies delayed medications and treatments for human patients?

Do drugs continue to be tested on animals after they have been released for human use?

What is postmarketing drug surveillance, and how would it be more effective than animal testing in monitoring side effects?

Wouldn't the tragedy of thalidomide have been avoided if more animal studies had been done?

Is it true that all the Nobel Prize winners in medicine used animals in their research?

What is xenotransplantation, and why do anti-vivisectionists oppose it?

Could xenotransplantation really create an epidemic of new diseases in humans?

What animals are used in experimental xenotransplants?

Isn't xenotranplantation the most practical solution to the shortage of human organ donors?

Have any human patients received a xenograft?

What are transgenic animals?

What are some of the advances that have been made without the use of animals?

How do autopsy studies advance medical knowledge?

What are clinical studies?

What are epidemiological studies, and how are they more effective in revealing the nature of disease than animal studies?

What are some non-animal technologies that have emerged in recent years?

What is in vitro technology?

What is the Human Genome Project, and how will it advance medical knowledge?

What non-animal methods have been shown to be more effective in our understanding of cancer?

Why aren't non-animal methodologies used more extensively?

Why do non-animal alternatives have to be "validated"?

What is the process for validating a non-animal alternative?




What are the different ways animals are used in biomedical research?

There are basically seven ways animals are used in medical science: 1. Animals are used as spare parts, such as heart valves and insulin. 2. Animals are used as factories, such as for the production of monoclonal antibodies. 3. Animals are used as models for human disease. Most animal research is designed to study the nature of specific human diseases and find treatments and cures for them. 4. Animals are used as test subjects. Animals are used to test pharmaceutical drugs, not only to see if they are effective against a particular disease or condition, but also to measure toxicity levels and to identify adverse reactions. In addition to pharmaceutical drugs, animals are used in testing the potentially harmful effects (such as carcinogenecity) of chemicals used for industrial purposes as well as other substances in the environment. Surgical techniques and procedures, including transplantation procedures, as well as medical devices, are also tested on animals. 5. Animal tissue is used to study basic physiological principles. 6. Animals are used for dissection in educating medical students. 7. Animals are used as a modality for ideas—that is, to test scientific theories and principles.
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Has the number of animals used in biomedical research increased or decreased over the years?

Overall the number of animals used has decreased, however the number of animals used for genetic engineering and cloning purposes are increasing.
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Where do laboratories obtain the animals they use for biomedical research?

Generally, animals used in research are the result of years of selective breeding, which ensures that animals are uniform in size and other characteristics, and that they share a common genetic background. Most purpose-bred animals are young and small in size. Researchers obtain purpose-bred animals through animal breeders and biological supply houses. Genetically engineered mice and rats—animals that have, through gene manipulation, been bred to have or lack certain characteristics—are also available. Often, researchers raise their own animal subjects in breeding colonies on the laboratory’s premises. Where certain research projects demand a more genetically diverse population, researchers often turn to the local pound. By law, scientists are allowed to procure animals from pounds for research purposes. However, some municipalities, responding to the concerns of anti-vivisectionists and other animal advocates, have enacted pound seizure laws, which prohibit researchers from taking animals from pounds and shelters. In such cases, researchers turn to Class B dealers, who turn a profit by selling to researchers animals they have acquired from their owners, from pounds and from other dealers.
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Isn't animal research the most effective way to test new medicines and surgical instruments and procedures?

Animal research is a highly ineffective way to test new medicines and surgical instruments and procedures because animals are different than humans in many ways, not only on a gross anatomical level but, perhaps more importantly, on a cellular and subcellular level. Because human and nonhuman animals are very different physiologically, metabolically, anatomically, genetically and psychologically, animal tests predict results only on the specific animal being tested. Attempts to extrapolate results of an animal experiment to humans are likely to produce false and misleading data.
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How does animal research sidetrack medical progress and compromise human health?

Animal research delays medical progress and compromises human health in a number of ways. Because animal research often cannot adequately predict how a human will react to a test drug, a carcinogen or a surgical procedure, these studies have little or no value. They are expensive and time-consuming, wasting time and money that would be better used in other, more effective kinds of research. All too often, researchers assume that the results of an animal test are applicable to humans, and then conduct additional research before it is proven that the animal tests are worthless. Because pharmaceutical drugs are tested on animals before they go to clinical (human) trials, side effects that were not demonstrated in animals have often caused harm, and even death, in humans. There is also the question of how many medicines that could have helped humans are disregarded because they failed to work in animals.
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Aren't people and animals enough alike to make animals adequate test subjects for humans in the laboratory?

The gross similarities between humans and nonhuman animals make it seem as if animals are “close enough” to humans that they can stand in for them in the laboratory. But close is not good enough. Because each individual species has unique characteristics, animal tests can only adequately predict results on the specific animal species upon which it was conducted.
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Why are rodents inadequate models for human disease?

Because of the obvious (and not so obvious) biological differences between rodents and humans. Rodents not only have a slower metabolism than humans, they distribute and excrete toxic substances differently. And that’s just the beginning. In rodents, plaque (fatty deposits) is deposited in the liver, whereas in humans, plaque is deposited in blood vessels. Rodents manufacture Vitamin C in their bodies, but humans can only obtain Vitamin C through their diet. Rodents require 3-1/2 times more protein than humans. And they cannot tolerate more than 15 minutes of direct sunlight. These and the other ways rodents and humans differ anatomically, metabolically and physiologically create a number of problems in the laboratory. For example, some common tumors such as prostate, colon and rectal tumors are rare in rodents, and when they are artificially induced in mice and rats in the laboratory, the tumors behave much differently than they do in humans. Furthermore, colon cancer in rats kills by obstructing the colon; human colon cancer kills by metastasizing (spreading) to other places in the body. There are other differences as well. In rats, the small bowel is most often affected; in humans, it is the larger bowel. At first glance, the fact that mice are highly susceptible to tumors of the mammary glands, liver, pituitary, thyroid, lung and lymph systems would make them suitable models for humans. However, a closer examination reveals that even though they are located in the same regions, they are not the same cancers.
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Can the results of studies from different species within the same genus give different results?

Yes. Animals are complicated creatures with multiple organ systems that interact with each other in many subtle ways. Often these complex interactions are not fully known or understood. Dual experiments at Carnegie Mellon University, which tested the ability of 214 compounds to cause cancer in both rats and mice, agreed with each other only 70% of the time. In other words, rats and mice had a different reaction to the tested chemical 30% of the time. Another study revealed that only 54% of chemicals found to be carcinogenic in one species were also carcinogenic in the other. For example, liver tumors can be induced via chemicals in mice, but the same chemicals do not induce cancer in rats or hamsters. Benzedrine causes bladder tumors in humans, liver tumors in hamsters and middle ear tumors in rats. Studies have even shown differences within genders of the same species. Of 33 chemicals that caused cancer in both rats and mice, only 13 caused cancer in both males and females.
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Wouldn't medical progress come to a grinding halt if we stopped experimenting on animals?

In reality, animal experimentation has not helped people nearly as much as it has thwarted progress in the life sciences. Because animal research often gives false or misleading results, it wastes valuable time, often delaying life-saving treatments while rushing questionable and possibly harmful therapies to the marketplace. Some of our most significant breakthroughs in medicine have been made without animals. These include x-rays, MRIs and CT scans. With dramatic advances in technology, even more exciting new research modalities are on the horizon. If the funds that are currently allocated to animal research were redirected to the non-animal research modalities that have proven to be far more effective, as well as emerging technologies that have the potential to change the face of medicine, progress would probably advance at a far quicker pace.
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Has animal research ever contributed to medical knowledge?

In some instances, animals have contributed to advances in human medicine, but history has shown that animal experimentation has not helped people nearly as much as it has actually thwarted progress in the life sciences. Whatever limited contributions may be attributed to animal research, it does not exclude the possibility that the advances could have been achieved through other means. In fact, some of our most significant breakthroughs in medicine have been made without animals. These include x-rays, MRIs and CT scans. In the medical field, it has been demonstrated repeatedly that pharmaceutical drugs and surgical techniques developed using animals cannot be reliably applied to humans. In the field of psychology, most of what we’ve learned through animal experimentation is about animal, not human, behavior. Besides, medical knowledge has now progressed to the point where the vast majority of research is conducted at the cellular and subcellular level, which is the level at which human and nonhuman animals exhibit the most dramatic differences. In animal experiments, these differences result in false and misleading data. By depending too much on animal experiments, we are potentially missing many more paths to effective treatment.
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Don't surgeons train on animals before operating on humans?

Surgeons-in-training have long “practiced” on pigs and other animals, yet many have admitted that work on animals confuses procedures, and there are many examples to support their concern, including the following: · Ophthalmologists perfected radial keratotomy on rabbits, then tried it on humans. Only after completely blinding several humans did they finally correct the procedure. · Extracranial-intracranial (EC-IC) bypass procedures for inoperable carotid artery disease were tested and perfected on dogs and rabbits. Neurosurgeons performed thousands of EC-ICs before it was discovered that the operation did more harm than good. More patients died or suffered strokes because of the operation than were saved as a result of it. · No matter how many practice surgeries on animals in which organs are transplanted from one creature to another, the first human operations have always failed.
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If animal research is so ineffective, why do scientists continue to do it?

Many factors perpetuate animal experimentation, but the most obvious is momentum. Animal research is a deeply entrenched practice, and the system is highly resistant to change. Scientists who have devoted their entire careers to animal experimentation are reluctant to admit that these methods are useless, much less dangerous to humans. Some research scientists do not even realize the error of their ways. Far removed from patient care, they revel in the sheer glory of discovery, never pausing to question the applicability of their investigations. Never do they consider the human patients who are deprived of useful remedies while they squander money on knowledge for the sake of knowledge. Animal experimentation works for them, if not for humankind. Another reason animal experimentation continues is profitability. Consider just how many corporations, institutions and other entities profit from animal research: scientists, physicians, hospitals, regulation agency bureaucrats, pharmaceutical companies, medical conglomerates, politicians, animal breeders and vendors, animal equipment manufacturers, lawyers, reporters and the news media, to name a few. Other companies, such as those that manufacture cosmetics and personal care and household products, which may or may not pose human health problems, use animal testing to secure themselves against possible lawsuits. The interdependency of these entities is finely tuned: the more animal experiments the researcher does, the more articles he or she publishes. The more articles published, the more grant money is received. The more grant money, the more money the university or research facility receives. The more money the university or research facility receives, the more animal research it can do. The more animal research data big business can obtain quickly, the faster it can take products to market without fear of litigation, and the more products it can sell. The more big business sells, the more money there is available for advertising. And advertising revenues support the news media. Anytime animal research is questioned, there is an outcry from each vested interest group, who move quickly to shore up their position.
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What about the claim by animal researchers that you must animal test in order to observe a "whole system" model?

It is true that in vitro (test tube) research methodologies, though tremendously valuable, cannot predict what will happen in a whole living system. But history has proven that laboratory results in animals are even more inadequate. Although successful in predicting what happens in a particular animal tested, animal studies do not predict what will happen in humans. Very often, substances that have proven effective in animals do not demonstrate curative value in humans, and may even harm them. (Just as often, animal testing often works at cross-purposes to discovery, when poor results prevent medications that could alleviate pain and save lives from being introduced into the market.) Because animal tests lack predictive value, all drugs must eventually be tested on humans in "clinical phases" of drug testing.
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If we didn't test on animals, how could we find cures for human diseases?

There is a wealth of investigative methods that produce results accurately, efficiently and at less cost than animal research. Some of these methods have been used successfully for centuries, such as autopsy studies, clinical observation and epidemiology (the study of the incidence of disease within segments of the human population). New technologies, such as computer simulations, mathematical modeling, in vitro research and diagnostic imaging also have the potential to replace animal research.
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Isn't the use of animals necessary if we are to find a cure for AIDS?

Over the last 20 years, billions of dollars have been spent trying to infect animals with AIDS, and these efforts have been entirely futile. It is true that researchers have succeeded in infecting chimpanzees with HIV; however, none has progressed to AIDS. The inability for researchers to produce an adequate animal model—despite years of effort and billions of dollars—makes it extremely unlikely that animal experimentation will lead us to therapies and cures for this terrible disease. Investing AIDS research money in animal research is therefore wasteful. With as many as 34 million people infected with HIV worldwide, blood cells from those already afflicted will serve as our most illuminating research material. In fact, in vitro research on human blood cells—not research on animals—has revealed a number of idiosyncrasies that allow HIV to proliferate freely and progress to AIDS in humans. The efficiency of the virus relies on very specific and minuscule aspects of human white blood cells called helper T-cells. These cells have portals on their surface called receptors. These receptors work in tandem with precise proteins to invite HIV into the white blood cell, where the virus then reproduces. Receptors can be very species-specific and sometimes vary even within a species, which explains why chimpanzees and even some people who are exposed to HIV never progress to AIDS. That is also how HIV-infected humans who do not progress to AIDS offer valuable insights into possible ways of countermanding the disease. Furthermore, the identity of those HIV-infected humans who do not progress to AIDS was derived through epidemiological studies, and in vitro research has isolated the human gene believed responsible for their immunity. The sequencing of the HIV genome was also accomplished through in vitro research. And the development of AZT and other anti-AIDS medications was not dependent on animal experimentation. In short, it has been human data, not animal research, that has reliably informed the development of HIV medications and the effort to produce a vaccine.
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Isn't the use of animals necessary if we are to find a cure for cancer?

Despite the fact that hundreds of millions of animals have been sacrificed, and billions of dollars invested, researchers appear to be losing the “War on Cancer” declared by the Nixon Administration more than 30 years ago. In fact, deaths from cancer are higher than ever. On the surface, that may lead one to believe that we should do more animal research. In fact, though, the opposite is true. Cancer research that relies on the animal model will almost certainly not lead us to the answers we need to eradicate cancer. Why? Because animal cancer is not the same as human cancer. While researchers have been highly successful in curing cancer in mice, those cures have not been translated to humans. That is not surprising, given the fact that there are over 200 different forms of cancer afflicting different organs, tissues and cells in humans, and although comparable animal organs, tissues and cells may become cancerous, the cancers are never identical to human carcinomas. As a result, data from animal cancers do not help us predict cancer (and its treatment and cure) in humans, thereby wasting valuable time and money—even while human cancer patients suffer and die. Another reason animal research has not helped bring about a cure for cancer is the fact that susceptibility to cancer may be genetic. In addition, diet, lifestyle and exposure to certain chemical elements are also contributing factors to the occurrence of cancer. In an effort to turn animals into adequate research models, researchers implant them with human genes, and then expose them to known human carcinogens. If we already have significant human evidence that a substance, diet or lifestyle is carcinogenic, why do we tool up to repeat that episode in animals? In any event, different substances are not necessarily carcinogenic to all species. Although one would expect rats and mice to acquire cancers similarly, studies conducted on both species found that 46% of chemicals found to cause cancer in rats were not cancer-causing in mice. Since species as closely related as mice and rats do not acquire cancer identically, it is not surprising that 19 out of 20 compounds known not to cause cancer in humans did cause cancer in animals. The National Cancer Institute treated mice that were growing 48 different “human” cancers with a dozen different drugs that were already used successfully in humans. The drugs did not work in 30 out of the 48 cancers; 63% of the time, the mouse models were wrong.
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Isn't the use of animals necessary if we are to find a cure for diabetes?

While it is true that animals have figured largely in the history of research and therapy for diabetes, their use has not been necessary and has not always advanced science. Diabetes is a very serious disease. It affects up to 14 million Americans and is a leading cause of blindness, amputation, kidney failure and premature death. Although the clinical signs of diabetes have been known since the first century AD, it was not until the 1700s that physicians using autopsy studies were able to associate the disease with changes to the pancreas. But because these pancreatic changes were difficult to reproduce in animals, many scientists continued to dispute the role of the pancreas in the disease. Nearly a century later, in 1869, scientists identified insulin-producing pancreatic cells that malfunction in diabetic patients. Other human pancreatic conditions, such as pancreatic cancer and pancreatitis (inflammation of the pancreas) were seen to produce diabetic symptoms, thus reinforcing the link between diabetes and the pancreas. However, animal experimenters continued to interrupt developing knowledge about this link. When they removed pancreases from dogs, cats and pigs, the animals did become diabetic, but the animals’ symptoms led to conjecture that diabetes was a liver disease. These animal studies threw diabetes research off track for many years. Defenders of animal research often point to the development of insulin as support for continued animal testing. In the early 1920s, two scientists, Macleod and Banting, isolated insulin by extracting it from a dog. They received a Nobel Prize for this accomplishment, but Macleod later admitted that their contribution was not the discovery of insulin, but rather the reproduction in the dog lab what had already been demonstrated in humans. They were not obliged to extract insulin from dogs, because ample human tissue was available. They did so merely because it was convenient. Later, Banting and other scientists modified the process of extracting animal insulin using in vitro techniques and mass-produced insulin from pigs and cattle by obtaining insulin from slaughterhouses. In coming years, scientists continued to refine the animal-derived substance. And although it is true that beef and pork insulin saved lives, it also created an allergic reaction in some patients. Injecting animal-derived insulin also presented the sizable danger of contracting viruses that cross from one species to another. Had researchers recognized these potentialities early on, particularly in view of the gulf of differences between humans and farm animals, they would have hastened to develop human insulin more quickly. The ability to treat patients suffering from diabetes without giving them insulin injections was discovered by chance on humans. Today, the administration of oral anti-hyperglycemics, which arose from serendipity (chance discovery) and self-experimentation, eliminates the need for insulin injections in many patients. Nevertheless, diabetes remains a stunningly enigmatic disease, in large part due to a continued reliance on animal models. Insulin is a treatment, not a cure, for this disease. The exact biochemical process through which insulin regulates blood sugar is not yet known. But in light of the differences between humans and animals on a cellular level, it is extremely unlikely that any revelations will come through animal research.
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Is it true that the availability of penicillin was delayed as a result of animal testing?

Yes. Animal tests sidetracked the development of this important drug. In 1929, Alexander Fleming observed penicillin-killing bacteria in a petri dish. Intrigued, he administered the compound to bacteria-infected rabbits, hoping that it would do the same thing. Unfortunately, penicillin was ineffective against the rabbit’s infection. (We now know that rabbits excrete penicillin into their urine so rapidly that the drug does not have a chance to take effect before it is eliminated.) Disappointed, Fleming set the drug aside for a decade, because, in his mind, the rabbits had "proven" the drug to be useless as a systematic medication. Years later, he recalled the drug when he had a patient near death, for whom all other treatments had proved ineffectual. In desperation, he reached for the penicillin. The patient survived, and the rest is history. It is fortunate that we didn’t have animal tests in the 1940s, for penicillin would probably never have been granted a license, and possibly the whole field of antibiotics might never have been realized.
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How could we have discovered a vaccine for polio without using animals?

In fact, animal experimentation delayed this much-needed vaccine throughout the first half of the 1900s. In 1908—73 years after the first polio outbreak—scientists suggested that a virus was responsible for the disease, and that a vaccine could be developed to eradicate it. In 1912, pathologists discovered the poliovirus in human intestines, which suggested it might enter humans through the digestive track. This was a critical discovery, because in developing a vaccine, it is very important to determine how the infection enters the body and takes hold. Its contagion cannot be interrupted without first determining its path. Meanwhile, researchers successfully infected monkeys with polio. However, monkeys contract polio nasally (through the nose), and the virus moves directly to the brain. Incredibly, scientists working on the vaccine chose to ignore the human digestive data in favor of the monkey data, thereby postponing the development of a vaccine by decades. In 1934, a polio vaccine manufactured from monkey tissues was released, and it resulted in the paralysis of 12 people, and the deaths of six others. In 1937, animal experiments led scientists to spray zinc sulfate and picric acid alum into the noses of children. These scientists reasoned that if the human transmission route was through the nose, as it was in monkeys, that this would kill the virus in the nose. The only result was that some children permanently lost their sense of smell. In 1941, 30 years after the original animal experiments, Dr. Albert Sabin worked with autopsy findings to demonstrate that the human nasal mucosa did not have the virus. What he did find was that the virus was confined to the gastrointestinal tract, as had been determined near 30 years earlier. In 1949, John Enders grew the virus in tissue culture, thus paving the way for a vaccine, and in 1954 received the Nobel Prize in Physiology or Medicine for his achievement. The vaccine could have been produced from non-animal tissue; however, manufacturers opted for monkey kidney tissue instead. The first animal-based vaccine contained live virus, killing 11 people and causing 204 others to contract polio. Today, the polio vaccine is grown in human diploid-cell culture, rather than animal tissue.
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How do animal studies impact on the drug development process?

Rather than safeguarding consumers, animal tests create a false sense of security with regard to the safety and effectiveness of drugs, working against the health interests of the public and diverting precious research dollars away from solid, human-based testing methodologies. Animal studies provide only two sure things: a very accurate picture of the effects of a drug on animals in the laboratory, and a legal safety net for the government and pharmaceutical companies. Beyond that, drugs that have been released to the public based on misleading animal studies have caused harm and even death to tens of thousands of people. Animal testing in no way provides any real indication of how a drug will affect humans because animal models are an ineffective way to extrapolate data for human reactions. Although subjecting the substances to animal testing is designed to reveal anticipated effects and side effects in humans, very often the results differ dramatically between species. Substances that could save many human lives are not approved because they are harmful to animals, thus preventing ill patients from receiving the medicine they need. Likewise, substances that are therapeutic to animals get approved, but then sometimes harm and kill humans. An astonishing number of animal-tested drugs make it to market, only to cause problems later. It is well accepted that about 100,000 deaths per year and about 15% of all hospital admissions are caused by adverse reactions to medications. Between 1976 and 1985, 102 of the 198 new medications that had undergone extensive animal testing were either withdrawn or relabeled by the FDA due to severe and unpredicted side effects.
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How would we determine the safety of drugs for human use without first testing them on animals?

In vitro testing, computer modeling, epidemiology, clinical observation (monitoring human patients), and autopsy of humans are the only truly accurate methods for obtaining knowledge about the positive and negative effects of medications on humans. More extensive preclinical testing on human tissue, more extensive clinical trials and mandatory postmarketing drug surveillance would offer the public much safer medications.
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If you want to avoid subjecting human patients to unexpected side effects, why not conduct more animal tests during the development process?

Because reaction to a drug can vary by species, animal tests cannot predict response in humans. Because they cannot reliably predict a human response, data from animal studies cannot be reliably extrapolated to humans. No amount of animal testing, and no matter how many different animal species are tested, can change this fact. There is simply no guarantee that the medications will behave the same way in humans as they do in animals.
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How can we know what medications will cause birth defects without first testing them on animals?

A principle called Karnofsky’s Law states that any substance can be teratogenic (causing birth defects) if given to the right species, at the right stage in development and in the right dose. In other words, all medications can cause birth defects in all creatures—and a vast amount of experimental data support this rule. The problem with animal testing drugs for teratogenicity is the fact that not all species are equally susceptible to teratogenic influences by any given chemical. Likewise, an agent that is teratogenic in some species may have little or no teratogenic effect in others. For example, according to the New England Journal of Medicine, out of more than 1,200 tested chemicals that cause birth defects in animals, only 30 cause them in humans. Thus, animal tests have no predictive value, except for the species being tested. Because they cannot reliably predict teratogenicity in humans, animal tests fail miserably as a way to evaluate the safety of a drug.
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Are there any examples of drugs that have caused birth defects in humans, but not in animals?

Researchers have not been successful in reproducing birth defects in animals for the following drugs, which cause birth defects in humans: · Captopril · Enalapril · Minoxidil · CCBs · Warfarin .
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What are some examples of drugs that have caused birth defects in animals, but not in humans?

Many safe and useful drugs have been shown to cause birth defects in animals. These include: Lovastatin, Chondroitin sulfate, Acetazolamide, Dichlorphenamide, Ethoxzolamide, Methazolamide, Furosemide, Clonidine, Diazoxide, Hydralazine, Reserpine, Guanabenz, Diltiazem, Nifedipine, Codeine, Hydrocodone, Hydromorphone, Meperidine (Demerol), Morphine, Oxymorphine, Phenazocine, Propoxyphene, Colchicine, Allopurinol, Aspirin, Acetaminophen, Enflurane, Ether, Halothane, Isoflurane, Methoxyflurane, Nitrous oxide, Sevoflurane, Procaine, Corticosteroids, Ampicillin, Cephalothin, Chloramphenicol, Erythromycin, Antiparisitics, Anthelmintics, Antimalarials, Anti-hyperglycemics, Insulin, Thyroxine, Triiodothyroacetic acid, Methylthiouracil, Propylthiouracil, Aminophylline. Most of the medications used to treat nausea, vomiting, allergic conditions, and respiratory ailments, as well as many antibiotics, antifungal medications and antiviral medications, and a number of non-steroidal anti-inflammatory drugs, cause birth defects in animals, but not humans.
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What are some examples of pharmaceutical drugs that caused serious side effects not revealed in animal studies?

The list, unfortunately, is a long (and devastating) one. Here are a few examples, which represent a mere fraction of the medications that passed animal tests, and then went on to produce severe to life-threatening problems, and even death, in humans: · Diethylstilbestrol (DES), prescribed to pregnant women to prevent miscarriages, caused spontaneous abortions, premature birth and neonatal death, and increased the risk of vaginal and cervical cancer in the patients’ daughters. · Rexar, an antibiotic, was withdrawn after it was linked to severe cardiovascular events and seven deaths. · Celebrex, an arthritis drug, was linked to ten deaths and 11 cases of gastrointestinal hemorrhage in its first three months on the market. · Zimeldine, the first SSRI (selective serotonin reuptake inhibitor), was withdrawn after causing a paralyzing illness known as Guillain-Barre syndrome. · Zafirlukast (Accolate), a common medication used to treat asthma, has recently been linked through human studies to a rare and sometimes fatal condition known as Churg-Strauss syndrome. · Chloramphenicol, an antibiotic, caused life threatening aplastic anemia, which could have been predicted by in vitro testing with human cells. · Fialuridine, designed to counteract hepatitis B, caused liver damage in seven out of 15 people, five of whom eventually died and two more needed liver transplants. · Isuprel (isoporterenol), a drug used to treat asthma, proved highly toxic for humans in the dosages recommended for humans based on animal studies, with 3,500 deaths of asthmatics in Great Britain. · Methysergide, a migraine medication, led to retroperitoneal fibrosis (severe scarring of the heart, kidneys and blood vessels in the abdomen). · Suprofen, an arthritis drug, was withdrawn from the market when patients suffered kidney toxicity. · Selacryn, a diuretic, was withdrawn after 24 people died from drug-induced liver failure. · Perhexiline, a heart medication, was withdrawn when it produced liver failure. · Domperidone, designed for nausea and vomiting, was withdrawn because it made patients’ hearts beat irregularly. · Novantrone (Mitoxantrone), a cancer treatment, produced heart failure in humans. · Carbenoxalone, designed to prevent the formation of gastric ulcers, caused people to retain water to the point of heart failure. · Cleocin (Clindamycin), an antibiotic, causes pseudomembranous colitis (a bowel condition). · Linomide (roquinimex), for the treatment of multiple sclerosis, was withdrawn from clinical trials after several patients suffered heart attacks. · Cylert (pemoline), used to treat Attention Deficit Hyperactivity Disorder in children, caused liver failure in 13 children, 11 of whom either died or needed a liver transplant. · Eldepryl (selegiline), used to treat Parkinson’s disease, induced very high blood pressure in patients. · The combination of fenfluramine and dexfenfluramine, a diet drug, was withdrawn when it was linked to heart-valve abnormalities. (Physicians in Belgium reported heart abnormalities in patients using the medications as early as 1994.) · Troglitazone (Rezulin), a diabetes medication, has caused death due to liver failure in as many as 155 people. · Seldane (terfenadine), an allergy drug, caused life-threatening heartbeat abnormalities in humans before it was withdrawn from the market. · Duract (bromfenac sodium), a non-steroidal anti-inflammatory, has caused fulminant hepatitis and liver failure. · Omniflox, an antibiotic, was recalled after several deaths. · Floxin, an antibiotic, was found to cause seizures and psychosis in humans.
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What are some examples of cases where animal studies delayed medications and treatments for human patients?

There are many cases in which the mandate for animal testing prevented the development and distribution of valuable medications, thus initially depriving American patients of much-needed treatments and cures. Here are just a few: · The contraceptive Depo-Provera was barred in the U.S. from 1973 to 1993, even though it was used by women and found safe elsewhere in the world, because it caused cancer in dogs and baboons. · Clinical trials of the drug digitalis, used to treat heart disorders, was delayed when it caused high blood pressure in animals. · FK 506, now marketed as Tacromilus, an antirejection agent, was almost shelved before proceeding to clinical trials because of severe toxicity in dogs. · Prilosec (Omeprazole), a widely used gastrointestinal medication, was delayed for years and almost canceled because of an effect in animals that did not occur in humans. · Furosemide (Lasix), a diuretic used to treat high blood pressure and heart disease, was almost lost to the public because it was found to cause liver damage in mice, rats and hamsters. · Fluoride, which provides protection against cavities, was initially withheld from dental use because it causes cancer in rats.
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Do drugs continue to be tested on animals after they have been released for human use?

When an unexpected side effect occurs in humans, scientists will conduct retrospective testing, which involves trying to reproduce the side effect in animals.
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What is postmarketing drug surveillance, and how would it be more effective than animal testing in monitoring side effects?

Postmarketing drug surveillance is the reporting of any side effect of a medication after its release. It has the potential to circumvent many disasters, while also having the added benefit of increasing the odds of finding new uses for old drugs. Unfortunately, no surveillance systems are currently required, and doctors do not often volunteer to report side effects.
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Wouldn't the tragedy of thalidomide have been avoided if more animal studies had been done?

In fact, animal testing delayed the withdrawal of this drug and resulted in thousands of children born with phocomelia (the lack of developed limbs). Thalidomide was prescribed to pregnant women to prevent miscarriage and also to relieve morning sickness. The first case of phocomelia in infants of mothers taking thalidomide was reported in 1956, yet the drug was released in 1957 anyway. (Toxicity tests on animals had been conducted, including some on pregnant rodents, where phocomelia did not occur.) As the incidence of phocomelia increased, scientists attempted to reproduce the phenomenon in a wide range of animal species, looking for proof in animals of what they already knew was occurring in humans—that thalidomide was drastically damaging unborn offspring. Eventually, one breed of rabbit, the White New Zealand rabbit, was affected, but only at a dose between 25 and 300 times that given to humans. Some monkeys gave birth to deformed offspring, but it took ten times the normal dose to make this happen. The drug was not withdrawn until 1962, five years after obvious and graphic epidemiological evidence in the form of hundreds of babies born with flippers or no limbs at all was available, but largely ignored. In the end, more than 10,000 additional children were born with phocomelia.
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Is it true that all the Nobel Prize winners in medicine used animals in their research?

Most of them did, but in no case does that mean the discoveries would not have been made without animals. It only means that the market for “laboratory” animals was thriving, and using them was the easiest, most convenient method. Beginning in the 1850’s, experimentation on animals became part of all medical curricula, and researchers were obliged to perform animal experiments to obtain their degrees. However, it is incorrect to assume that those experiments bore directly on the Nobel-winning results. In those instances where animals were used for Nobel-winning results, they were not necessary. Although animal tissue research was the convention, human tissue was available and more viable.
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What is xenotransplantation, and why do anti-vivisectionists oppose it?

Xenotransplantation is a procedure in which the cells, tissue and organs of nonhuman animals are implanted into humans. Xeno in the word xenotransplantation comes from the Greek word meaning strange or foreign. Cross-species transplant experiments have been conducted since 1963, when a human patient received a baboon kidney at Hennepin County Medical Center in Minneapolis, MN. The organ functioned four days. Anti-vivisectionists object to using animals as "factories" for spare parts in cases where human organs no longer function. In addition, xenotransplantation has the potential to threaten public health and safety by enabling dangerous infectious diseases and viruses to cross the species barrier and spread disease among the human population.
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Could xenotransplantation really create an epidemic of new diseases in humans?

Transplanting living animal organs into humans bypasses natural barriers that prevent infection. This process makes it easier for infectious diseases and deadly viruses to pass from animals to humans, which could cause illness and death of the recipient, as well as the spread of disease to epidemic levels. With the very real possibility that deadly infectious agents could find a compatible home in a human, then transmit itself from human to human, mutating along the way, xenotransplantation could very well unleash an epidemic that could outstrip AIDS in its devastation. Even the most careful screening of a donor animal is no guarantee of safety. There is no such thing as a "virus free" animal. Moreover, scientists can only screen for known viruses and other disease agents. They have no way of screening for disease agents that have yet to be discovered. Consider prions, an entirely different form of infectious substances, which were not discovered until 1982. (Prions are responsible for Mad Cow Disease and other transmissible spongiform encephalopathies.) These infectious substances lie dormant in living systems for years before bringing on lethal disease. So far, they cannot be killed or controlled. And prions may be found in pigs, which are now the favored animal for experimental xenografts.
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What animals are used in experimental xenotransplants?

At first glance, it may seem that primates would be the logical choice for organ cultivation, because of their genetic similarity to humans. But that proximity creates a potentially deadly problem, because the closer the donor species, the more likely it is to transmit lethal diseases. In the past, baboons have been used in experimental xenotransplant operations. Recently, however, scientists have switched to genetically-engineered pigs. These are pigs that have had human DNA injected into them as fetuses. (The fetus's system does not attack the foreign DNA, because immune response is unformed in fetuses.) Once born, pigs mature and reproduce quickly, and each succeeding generation has more human DNA introduced into their fetuses. As time goes on, the pig organs become more like human organs in terms of immune recognition.
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Isn't xenotranplantation the most practical solution to the shortage of human organ donors?

Absolutely not. Yes, there is a severe shortage of human donor organs in the U.S. today. But if more human organs were available, there would be no need to pursue the highly questionable and potentially dangerous xenotransplantation experiments. A relatively small increase in organ donations, combined with an improvement in the way organs are procured, would provide a sufficient number of organs to meet the demand. The U.S. should consider following the lead of many European countries, including France, Austria, Belgium, Denmark and Sweden, which have passed "presumed-exempt" laws. These laws presume that an individual’s organs are available for clinical use unless the individual specifically states otherwise. When Belgium passed its presumed-exempt law, organ donation increased by 183 percent.
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Have any human patients received a xenograft?

Yes, several humans have received experimental xenografts. In 1963, six humans received a baboon kidney. In 1964, researchers attempted to transplant a chimpanzee heart into a human. Between 1969 and 1974, three children received transplanted livers from chimpanzees. In 1993, researchers tried a baboon-to-human kidney transplant, as well as a bone marrow transplant from a baboon to a human patient with AIDS. Perhaps the best known human xenograft patient is Baby Fae, who received a baboon heart in 1984. None of these procedures were successful. In 1999, the U.S. Food and Drug Administration (FDA) announced a de facto ban on clinical trials of xenotransplants from nonhuman primates to humans.
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What are transgenic animals?

Transgenic animals are mutants that have selected human genes in their bodies, which make them more susceptible to certain human diseases or enable them to produce certain human antibodies, tissues, or even whole animals. These new species are created in the laboratory by manipulating an animal's genes in several different ways, such as cutting or recombining an animal's DNA, by adding or deleting segments of DNA, by injecting human genes into animals, or by transferring genes from one species to another. Transgenic animals, also called genetically engineered animals, are seen by researchers as an improved animal model for studying specific diseases because they are more "human." For example, there are transgenic mice who have been specifically designed to have weakened immune systems, so that their bodies are more prone to develop cancer quickly (and develop larger tumors) in the laboratory.
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What are some of the advances that have been made without the use of animals?

Following are just a few examples of the many medical advances made throughout the ages that did not involve animal research: · Discovery of how blood circulates from the right heart through the lungs back to the left heart and into the arteries and veins. · The germ theory of disease, the sterilization process and the pasteurization process. · Isolation of the HIV (human immunodeficiency virus). · Discovery of the mechanism of AIDS transmission. · Development of x-rays. · Interpretation of the genetic code. · Production of Humulin, a synthetic copy of human insulin which causes fewer allergic reactions than animal-based insulin. · Development of a vaccine against yellow fever. · Understanding of cholesterol biochemistry and familial hypercholesterolemia. · Discovery of the chemical and physiological visual process in the eye. · Development of anti-depressant and anti-psychotic drugs. · Discovery of human blood groups. · Discovery of the relationship between chemical exposure and birth defects. · Discovery of the effectiveness of digoxin (digitalis) in treating heart failure and irregular heartbeat. · Discovery of the anti-malarial drug quinine. · Discovery of aspirin. · Discovery of penicillin. · Use of nitrogen mustard, prednisone and acinomycin D as cancer treatments. · Discovery of potassium bromide as an epilepsy treatment.
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How do autopsy studies advance medical knowledge?

Autopsies are an essential source of medical knowledge because if you want to know what caused a failure, you must study the failed entity. In the past, when autopsies were performed on a more frequent basis, autopsies were responsible for a number of significant medical breakthroughs. For example, it was through the study of cadavers that William Harvey was able to make the first accurate description of the blood’s circulation around 1628, putting to rest the numerous misinterpretations that were made as a result of animal dissection. Autopsy studies have also been responsible for advancing knowledge of: · Diabetes · Hepatitis · Appendicitis · Rheumatic fever · Typhoid fever · Ulcerative colitis · Congenital heart disease · Hyperparathyroidism · Mechanisms of shaken baby syndrome · Sudden infant death syndrome · Head injuries suffered during car accidents.

Unfortunately, the rate of autopsies has dropped in recent years, and many opportunities for retrieving valuable information are being missed.
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What are clinical studies?

Clinical studies are also known as clinical trials. These studies involve human volunteers and are designed to answer specific questions about the safety and effectiveness of a pharmaceutical drug or other therapy. Clinical studies are conducted after a drug has completed laboratory and animal testing. Clinical studies are conducted under the strict ethical guidelines to protect the rights of the people involved. Individuals who are considering entering a clinical trial receive informed consent documents that outline why the research is being done, what the researchers hope to accomplish, what will be done during the trial, how long the trial will last, the risks and potential benefits, and what other treatments are available.
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What are epidemiological studies, and how are they more effective in revealing the nature of disease than animal studies?

Epidemiology is a field of research in which data regarding the incidence and prevalence of specific diseases among populations is gathered and analyzed. It provides valuable information about how and why an illness occurs. Epidemiology allows researchers to identify environmental and lifestyle factors that influence susceptibility to certain illnesses, so that illnesses can be prevented before they occur. Epidemiologists have had an especially important role in uncovering the nature of occupation-induced diseases. Epidemiological studies identified the association between industrial chemicals and disease, such as phosphorous poisoning in munitions workers, mercury poisoning in felt workers and carbon monoxide poisoning in munitions workers. It was through epidemiology that we learned how AIDS is transmitted, as well as the cause/effect relationship between smoking and cancer, heart disease and cholesterol.
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What are some non-animal technologies that have emerged in recent years?

Emerging technology has had a tremendous effect on the development of non-animal research methodologies, and the innovative techniques and procedures that are now defining the frontier of medicine would fill an encyclopedia. Today, these technologies are providing physicians with a whole new level of information that they can use to ensure more accurate diagnoses of illnesses in a patient and an appropriate treatment program. Some of the highlights—which represent only a tiny fraction of the non-animal advancements made in recent years—include: · Interactive computer simulations that predict how a particular drug will affect a person’s respiratory or circulatory system. · Data mining techniques that analyze drug information databases to find previously undiscovered applications for pharmaceuticals that have already been studied. · Diagnostic imaging technology, including magnetic resonance imaging (MRI), positron electron tomography (PET), computer-aided tomography (CAT) and ultrasound. · Mathematical modeling, in which computers simulate parts of the human body as mathematical equations. · Lasers, which have a wide range of applications in medicine, including eye surgery, the treatment of skin disorders, and as a replacement for the scalpel in many types of surgery. · New DNA chip technology that can be used to differentiate clinically distinct cancer types and discover clinically important tumor subtypes. · Acoustic microscopy, which demonstrates internal conditions using sound waves without requiring dyes.

A wealth of innovative technologies are on the horizon, too. Research using stem cells, the Human Genome Project and the Human Proteome Project all hold the promise of cures that we would never have discovered using animal models. As we understand more how genes are involved in disease, we will be able to test potential drugs to see what effect they have on the DNA that comprises the gene. In the emerging field of pharmacogenomics, scientists can employ a “gene-to-drug” strategy to predict a person’s response to a given drug before exposure to the drug and customize therapies to meet explicit genetic criteria.
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What is in vitro technology?

In vitro research, also known as test tube research, enables researchers to grow human cells and tissues outside the body in a controlled environment. The cells or tissue, which have been removed from humans during surgeries, biopsies, and autopsies, are cultivated in flasks, test tubes or other special containers, enabling researchers to study the effects of a chemical substance on a living cell. In vitro research allows scientists to explore the nature of disease exactly where it occurs—at the cellular and subcellular level—in actual diseased human body matter, rather than an animal form of the disease.
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What is the Human Genome Project, and how will it advance medical knowledge?

The Human Genome Project is an international scientific program which completed the process of analyzing the complete set of chemical instructions—the genome—that controls heredity in human beings. Understanding the genome will affect science and medicine on numerous levels. It will allow new drugs to be tailor-made for specific gene-induced diseases in specific individuals. Further research on common genetic variants and the genes involved with all common diseases, made possible by cracking the genetic code, will allow people to have their genetic profile determined from a single blood sample. They can then use this information, with the guidance of their physicians, to practice preventive medicine and focus on those organs and systems that are prone to dysfunction.
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What non-animal methods have been shown to be more effective in our understanding of cancer?

The best methods for screening chemicals for carcinogenicity and curative potential lie in in vitro, or test tube, technology. A combination of in vitro techniques and epidemiology (the study of disease incidence) is ideal for testing chemicals already in the marketplace. In vitro testing has also revolutionized diagnostic science. For example, the Pap smear, one of the oldest and most successful forms of in vitro testing, is now used in 97 percent of all cervical cancer diagnoses. Tremendous progress in cancer research has come through epidemiological studies that have linked disease to the lifestyle of populations. For example, it was through epidemiological studies that we learned the association between diet and cancer. Perhaps most significantly, by studying patients who have already developed cancer, researchers have been able to determine that some genes activate and deactivate the uncontrolled growth of cancer cells. Over the past 30 years, techniques for detecting early cancers—colonoscopy, breast examination and prostate examination among them—have improved the prognosis for many cancer patients. None of these benefited from animal experimentation.
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Why aren't non-animal methodologies used more extensively?

Because animal experimentation is a deeply entrenched practice that has the support of a wide range of special interest groups, including animal researchers at universities, hospitals and other institutions, pharmaceutical companies, government agencies, animal breeders and manufacturers of animal maintenance equipment and even the media. All these groups profit in some way from animal experimentation and naturally are very resistant to change. Another reason why some non-animal methodologies are not used more extensively is that they offer little or no financial incentive. For example, the rate of autopsies has dropped 75 percent from the 1950s because no one will pay for them; pathologists do not routinely perform autopsies unless an insurance company reimburses them, which does not usually happen. Epidemiology, the study of disease incidence among specific population groups, gives us the opportunity to prevent disease, which offers little interest to pharmaceutical companies, who make billions of dollars on treating disease that has already occurred.
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Why do non-animal alternatives have to be "validated"?

Every non-animal alternative that has been developed must go through a rigorous validation process before results from the test are regarded as reliable for general use. Validating a non-animal alternative ensures that it is proven ready for implementation, since unreliable tests could cause serious human injury.
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What is the process for validating a non-animal alternative?

The process of validation has a number of phases. These include: · Identification of the need for the test · Research to develop the test · A prevalidation study to determine variability · Performance assessment · Refinement of the protocol · Training of the technicians using an adequate number of test chemicals with known in vivo (intact animal) data · Selection of sponsors and management teams · The validation study and database · Peer review · Adoption of the test · Implementation Review and hearings are conducted by experts through the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) and the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), two government agencies that seek regulatory acceptance of validated toxicological testing methods that reduce, refine or replace animals.
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Maximum Tolerated Dose




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© 2013 National Anti-Vivisection Society is a
501(c)3 non-profit organization
53 West Jackson Blvd., Suite 1552
Chicago, IL 60604
(800) 888-NAVS or (312) 427-6065
Fax: (312) 427-6524
navs@navs.org
© 2013 National Anti-Vivisection Society is a
501(c)3 non-profit organization