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FREQUENTLY ASKED QUESTIONS
General Questions
7. WHAT DIFFERENCE HAS BIOMEDICAL RESEARCH MADE TO HUMAN HEALTH?
(Taken from Unit I, Chapter 4, of the Rx for Science Literacy teacher manual.)
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, many of which have been identified through research, has helped reduce mortality rates and has become the best medicine in preventing needless disease and disabilities. With the reduction in cigarette smoking, deaths caused by heart disease have dropped substantially. The healthy lifestyle choices we’ve made have forced change in public accommodations and even the way restaurants cook. We now have non-smoking sections and even entire non-smoking facilities; sugar and sweetener options; and food choices with less fat and cholesterol. The important thing to remember is that you and I, the public, made those changes, and we have the power to continue to make changes.
Think about the generations of children that won’t have certain childhood diseases because of vaccines. These diseases include measles, mumps, chicken pox and 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 only happens through medical research, which requires an investment. But that investment saves lives and money.
For example, biomedical research has resulted in...
Treatments for:
Heart Disease: Cardiac surgery may be the only means to help patients whose hearts are in disrepair. Until the 20th century, successful heart surgery was unthinkable because it was impossible to see inside a beating heart.
After decades of work with animal models, a heart-lung machine was developed. The machine takes over temporarily for the heart and lungs, rerouting blood and bypassing the heart so that surgeons can work inside it. Since its development 50 years ago, thousands of human and animal hearts have been repaired. In fact, close to 600,000 cardiac bypass operations are performed each year in the United States alone.
Diabetes: The term diabetes describes either a deficiency of insulin or a decreased ability of the body to use insulin, a hormone secreted by the pancreas that regulates the body’s use of carbohydrates (sugars and starches) and fats. It’s estimated that nearly 21 million Americans have diabetes, but about one-third — more than six million people — are not aware that they have the disease! Those numbers are on the rise, and health care providers are especially concerned about the increase of diabetes among young people. Health care providers think that a “couch potato” lifestyle and the availability of fast foods and snack foods has led to an epidemic of obesity — one of the primary risk factors for diabetes. Fortunately, losing weight and becoming more active has a positive effect on the disease for most people.
Years of research have led to great advances in diabetes treatment. At one time, insulin was obtained by isolating it from animal pancreases; now human insulin is manufactured by bacteria using genetic engineering techniques. In diabetics who still make insulin, which occurs in the earlier phases of the disease, a number of oral medications can stimulate release of insulin from the pancreas, increasing the body’s sensitivity to insulin and slowing the breakdown of sugar and starches in the digestive tract. New blood sugar monitoring equipment requires little blood to sample so finger sticks are almost painless, and new technology under development is working toward a bloodless monitoring system. Insulin pumps act more like the pancreas does, delivering the hormone in regular, small quantities. Transplantation of the entire pancreas or pancreatic islet cells (clusters of cells that produce insulin), although not common procedures yet, have helped some diabetics. Research continues on the use of transplanting pig pancreatic cells, which are encapsulated in a gel that allows the insulin to escape but prevents immune cells from attacking and destroying the pig cells.
Cancer: Ongoing biomedical research continues to seek treatments to prevent cancer from spreading throughout a patient’s body. Along with the development of new drugs, an innovative area of cancer research involves gene therapy. In general, gene therapies deliver instructions in the form of DNA sequences to diseased cells so that the cells can produce one or more therapeutic proteins. The new protein may be a substitute for the defective one in the cell, or it may “turn off” the gene that is causing the disease in the cell. In addition, research continues to enhance understanding of the disease itself. This greater understanding could lead to modifications in our environment or lifestyle in order to reduce the risk of developing cancer.
To treat leukemia, a form of cancer, bone marrow transplants were introduced in the 1970s. In 1979, Boston-area researchers announced a new bone marrow transplant procedure for children who do not have a suitable family donor. A method was developed that destroys leukemia cells in bone marrow before the marrow is returned to the child. In time, the treated bone marrow begins to produce normal, healthy blood components. During the time the bone marrow is being processed, the patient is treated in an isolation room with massive doses of drugs and radiation to destroy any remaining leukemia cells.
More than 25,000 bone marrow transplants were performed in the United States in 2004. The majority of these were for treatment of leukemia.
Protective Vaccines:
Early Vaccines: In the 18th century, outbreaks of infectious diseases such as cholera, smallpox and typhoid fever were commonplace. The average human life expectancy was 31 years.
However, in 1794, Dr. Edward Jenner developed a vaccine against smallpox, a disease that at that time killed one out of every 10 children younger than 4. As a result, inoculation campaigns against smallpox were launched in the United States and Europe. In 1967, the World Health Organization launched a global campaign, the success of which has, in effect, led to the eradication of smallpox.
A cholera vaccine was developed by Louis Pasteur in the 19th century. Building on the techniques he developed working with cholera in chickens, he then developed vaccines against anthrax and rabies.
Working with guinea pigs, sheep and other animal models, researchers developed a diphtheria vaccine in 1921 (although it did not become widely available until the 1930s). In 1921, almost 207,000 cases of diphtheria were reported; in 1961, there were 617 cases. Thanks to almost universal vaccination among American children and adults, diphtheria is now a rare disease.
Polio Vaccine: Until the development of a vaccine in the 1950s, poliomyelitis was a feared disease. However, a number of discoveries led to the vaccine, which has nearly eradicated the disease in the industrialized world.
In 1909, two researchers found that monkeys and apes may contract the disease from people. The electron microscope, which enables scientists to study extremely small forms of life, proved the existence of viruses in 1935. Researchers began to suspect that polio was caused by a virus. Several years later, this proved true.
In 1949, Jonas Salk identified three strains of virus that cause polio, and two years later, he published the results of a small clinical trial of a vaccine made from killed polio virus. In 1954, a large clinical trial proved that Salk's vaccine was 99 percent effective against Type 2 and Type 3 polio strains, and the vaccine was made available to the public. (Outbreaks continued to occur, however, among people infected with Type 1 virus.)
About this time, Dr. Albert Sabin was working on his own polio vaccine. Sabin's vaccine was administered orally and was made from live virus that was weakened or "attenuated," but not killed. This approach introduced the disease into the body, stimulating an immune response. Sabin's vaccine became the national standard. It could be dispensed easily on sugar cubes rather than by injection.
Chicken pox: Varicella, which got the nickname chickenpox because the blisters it causes look like chick peas, is a common and contagious disease. Although it is usually a mild disease, serious problems can occur, especially in adults. A vaccine became available in 1995 and is recommended for children 12 months or older who have not had the disease. While the Centers for Disease Control and Prevention (CDC) does not keep track of varicella cases for the entire United States, it has been monitoring the number of cases in three urban areas, which have dropped dramatically since the vaccine became available.
Hepatitis: Hepatitis A and B are serious liver diseases caused by two related viruses. The hepatitis B vaccine became available in 1989, and infants are now routinely vaccinated against the disease. Since the virus can cause liver cancer, the hepatitis B vaccine is our first anticancer vaccine. Right now the hepatitis A vaccine (available since 1995) is given to people traveling to developing countries and others at greater risk of contracting the disease (such as those who work with blood products). Hepatitis A vaccination is recommended for children over the age of 2 in selected states and regions and for certain high-risk groups, and it may become part of the routine immunizations given to babies. A combined A/B vaccine received approval in 2001.
Development of treatments such as:
Fluoride: Scientists noticed there was much less tooth decay in individuals living in areas where the water naturally contains small amounts of flouride. They also discovered strong teeth contain more fluoride than weak teeth. As a result of these discoveries, many communities began adding tiny amounts of fluoride to their drinking water around 1945. Over the past 60 years, the damage caused by tooth decay has been reduced drastically, primarily through the use of flouride.
Penicillin and Other Antibiotics: Louis Pasteur, who developed vaccines against cholera, anthrax and rabies, also uncovered the underlying principle
of antibiotics. He concluded that it should be possible to use harmless microbes to fight pathogens, an idea that was developed further by researchers in the 20th century.
These early 20th century agricultural bacteriologists began exploring the interrelationships among microbes. In the 1920s, researchers came up with the idea of isolating microbes that can perform a single activity. They then searched for a microbe capable of digesting the polysaccharide coating of the pneumococcus bacillus (a bacteria that causes one type of pneumonia). The first antibiotic isolated using this method was gramicidin.
Screening techniques for isolating additional antibiotics were then perfected. Actinomycin and streptothricin proved too toxic to animals to be used in human patients. However, streptomycin was isolated in 1943 and found to be effective against the tuberculosis microbe. In the following 10 years, a number of broad-spectrum antibiotics were discovered that are available today.
Alexander Fleming made the discovery now known as penicillin. Other researchers improved the methods for growing the penicillin mold and isolating penicillin. Pure penicillin was then tested in mice, rats, rabbits and cats. Then in 1941, the first human trials were conducted. Now widely available, penicillin has few side effects relative to other medications and remains one of the safest medications available.
However, despite the phenomenal history of success of penicillin, its value has been diminished somewhat by the widespread development of resistance among target microorganisms and also by some people’s allergic reactions to it.
Cyclosporine and Other Anti-Rejection Drugs: A primary cause of the failure of transplantation procedures is the rejection of transplanted organs by the patient’s immune system. The most encouraging development in combating organ rejection was the 1972 discovery of a drug called cyclosporine. Cyclosporine treatment suppresses a patient’s immune system enough to accept transplanted organs. Researchers have since discovered several more drugs to combat rejection.
Monoclonal Antibodies: Antibodies, proteins secreted by one type of white blood cell called B lymphocytes, are produced as a defense against infection.
Because they are made in millions of different forms, each with different markers that specifically recognize antigens (molecules foreign to the body), they are unique among proteins. Production of a particular antibody begins as the body responds to the presence of its complementary antigen.
Researchers make antibodies by injecting an antigen several times into an animal model, usually a rabbit or goat. The antibody-rich serum is then collected from blood samples. This antiserum contains a mixture of antibodies, each produced by a different B lymphocyte and each recognizing different parts of the antigen molecule. Purifying this mixture is a tedious process and often has limited success.
In the late 1970s, the development of monoclonal antibodies revolutionized the use of antibodies as tools in biomedical research. This technique involves the cloning of a single B lymphocyte so that uniform (monoclonal) antibodies can be obtained in large quantities. Cloning creates a population of cells from a single ancestor cell.
Because of their uniform specificity for a given antigen, monoclonal antibodies have an enormous advantage over conventional antisera containing mixtures of antibodies. For example, many blood tests today involve the use of monoclonal antibodies, and they are used more and more in cancer research. Researchers are designing monoclonal antibodies that can target particular antigens on the surfaces of tumor cells. As a result, cancerous cells will be destroyed while other cells nearby will survive. In AIDS research, monoclonal antibodies produced from rodents were used to identify a variety of T lymphocytes known as T helper cells, which are important in the normal operation of the immune system.
Surgical and other procedures:
Pacemakers and Other Artificial Devices: Developed in the early 1950s, artificial pacemakers are one of the best-known devices for correcting an erratic heartbeat. Today, programmable pacemakers last years before needing to be upgraded and are used to help both humans and animals.
Angioplasty: When blood flow is reduced by blockage of the coronary arteries, chest pains or a heart attack can result. A common procedure to open blocked arteries is a balloon angioplasty. The procedure takes only a few hours to complete and usually can be done without general anesthesia.
In balloon angioplasty, a thin tube (catheter) is inserted into a large artery in the arm or groin and is advanced up the aorta toward the heart. From there, it is carefully threaded into the narrowed coronary artery. A balloon at the tip of the tube inflates to open the blockage.
Organ Transplantation: The era of transplant surgery began in the 1950s. The organs it is possible to replace today include the inner ear, the cornea, glands, blood vessels, muscles, nerves, bone marrow, blood, liver, kidney, lungs, heart, pancreas and intestines. Research on tissue rejection continues so that survival rates from transplantation procedures can be improved.
Heart Transplantation: In 1960, Dr. Norman Shumway predicted the possibility of transplanting the human heart from one person to another. A year later, he successfully performed the operation on a dog. In 1967, Dr. Christiaan Barnard performed the first human-to-human heart transplant. Now, more than 2,000 heart transplants are performed each year.
Kidney Transplantation: In 1954, the first successful human kidney transplant was performed between twins by Dr. Joseph E. Murray. Later, Dr. Murray showed that transplants were possible in unrelated people if drugs were taken to suppress the body’s immune reaction. Dr. Murray won the 1990 Nobel Prize in Medicine for his pioneering work.
In 2004, more than 16,000 kidney transplants were performed in the United States. The success of such transplants was made possible by two key research advances. The first was the hemodialysis machine, which makes it possible for patients with diseased kidneys to have their blood filtered and cleansed while awaiting a transplant. The second critical advance was the discovery of immunosuppression drugs such as the cyclosporines. These drugs suppress a patient’s immune system in order to prevent rejection of the transplanted organ.
Liver Transplantation: In 1963, Dr. Paul Russell, following years of research on animal models, performed the first human liver transplant. Liver transplantation is considered the most difficult and challenging of the major organ transplants because it is a large organ, and it contains thousands of tiny blood vessels. It takes at least four hours to remove the donor liver, and another eight hours to transplant it into the recipient. By administering anti-rejection drugs, complications due to rejection of transplanted livers can be alleviated. About 6,000 liver transplants are conducted each year in the United States.
Corneal Transplantation: The cornea is the transparent portion of the eye that covers the pupil and the iris. It admits light. Worldwide, corneal disease is the most common cause of blindness, and children are its most frequent victims. Today, cornea transplants have been performed on infants as young as five-months-old. Because the cornea has no connection with the blood supply and receives its nourishment from the eye fluid, the danger of rejection is low.
Human Vaccines Developed through Biomedical Research:
Anthrax Vaccine: Few people were concerned about contracting anthrax before about two dozen people in the United States constricted the disease by handling contaminated mail in the fall of 2001. A vaccine has been available since 1970, but its use is recommended only for people who are exposed to Bacillus anthracis on the job (like lab workers), people who handle potentially infected animals in other countries (like veterinarians) and military personnel deployed to areas with high risk of exposure.
Cholera Vaccine: While cholera is not currently a life-threatening disease in the United States, it is still prevalent in parts of the Middle East, Latin America and Asia. A vaccine is available to protect travelers to countries in these parts of the world.
Diphtheria Vaccine (DPT vaccine): A killed virus is used against diphtheria and is usually given to children. The vaccine given, known as DPT, combines the diphtheria vaccine with tetanus and pertussis (whooping cough) vaccines. Adults generally receive tetanus/diphtheria booster shots every seven to 10 years.
Hepatitis A Vaccine: Hepatitis A is a serious liver disease that is usually spread by close contact with an infected person and sometimes by eating food or drinking water containing the hepatitis A virus. Right now the hepatitis A vaccine (available since 1995) is given to travelers in developing countries and others at greater risk of contracting the disease (like those who work with blood products); a combined Hepatitis A and B vaccine received approval in 2001. Hepatitis A vaccination is recommended for children over the age of two in selected states and regions and for certain high-risk groups, and it may become part of the routine immunizations given to babies.
Hepatitis B Vaccine: Vaccination against hepatitis B now is recommended for all babies and particularly is recommended for children who attend day care centers. In addition, travelers to a country where hepatitis B is prevalent, health care workers exposed to the hepatitis B virus and other high-risk individuals now have the option of protecting themselves against this disease.
Influenza Vaccine: In general, anyone who wants to reduce his or her chances of getting the flu can get vaccinated. However, it is recommended by the Centers for Disease Control and Prevention that certain people get vaccinated each year — either people at high risk of having serious flu complications or people who live with or care for those at high risk of complications.
Measles Vaccine (MMR Vaccine): A live, weakened measles virus is routinely given to infants, usually in combination with mumps and rubella vaccines (MMR vaccine).
Meningococcal Meningitis: While meningitis is relatively uncommon in the United States, the disease is prevalent in regions of Africa and South America. Several vaccines are available to protect travelers to these locations.
Mumps Vaccine (MMR Vaccine): The mumps vaccine is given to children in one dose, usually in combination with measles and rubella vaccines (MMR vaccine).
Pneumococcal Polysaccharide: Pneumococcal disease (pneumonia) kills more people in the United States each year than all other vaccine-preventable diseases combined. Although anyone can catch the disease, those at highest risk are people over age 65, the very young and people with special health problems like heart and lung disease, HIV, diabetes and some forms of cancer. The vaccine protects against 23 types of pneumococcal bacteria.
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