Children’s Neurological Disorders
Epilepsy, the most common neurological disorder among young people, affects almost 1 percent of the U.S. population. Epilepsy is a brain disorder that causes unpredictable, uncontrolled seizures. Head injuries, stroke, infections, or tumors can cause it. However, recent research indicates that inherited genes are involved in most cases. The most severe seizures can cause loss of consciousness, convulsions, and wild movements of the limbs.
Some 500,000 children and adults in the U.S. have at least one symptom of cerebral palsy, a disorder caused by damage to the brain, usually before or during birth. Cerebral palsy includes a group of chronic conditions affecting body movement and muscle coordination, caused by damage to one or more specific areas of the brain, usually occurring during fetal development or at birth. About 5,000 babies are diagnosed with the condition each year.
Tourette syndrome, spina bifida, hydrocephalus, microcephalus, and Moebius syndrome are also classified as children’s neurological disorders. Tourette syndrome causes uncontrolled actions such as verbal outbursts and muscular tics. Spina bifida is a spinal cord defect. Hydrocephalus and microcephalus are fetal defects characterized by abnormally large or small heads. Moebius syndrome affects the cranial nerves and sometimes causes skeletal abnormalities.
Rapid advances in brain scanning technology, especially magnetic resonance imaging (MRI) are contributing to recognition of the conditions and understanding their causes. These advances, combined with human genome research, allow scientists to design new drugs that are more specific, effective, and have fewer side effects.
Cerebral palsy prevention measures, mostly involving the mother, are being improved on the basis of new knowledge about the brain damage that causes the disorder. These measures are related to blood incompatibility and exposure to viruses and other infections during pregnancy.
Extensive research into neurological disorders is being conducted on genetically engineered laboratory mice in the U.S. and in Europe. The recent identification of three specific genes has brought researchers significantly closer to understanding inherited conditions that might cause epilepsy and other disorders.
Since the 1980s, thousands of people have benefited from technology that allows organs to be transplanted to replace a failing system. Heart, kidney, and lung transplants, among others, have allowed thousands of people to lead normal lives. Through current medical research, these surgeries are being perfected and long-term health questions are being answered.
A treatment to block organ rejection has remained effective for up to a year in monkeys that received transplanted kidneys. The experimental treatment will one day free some transplant patients from having to take anti-rejection drugs for the rest of their lives.
Trauma and accident victims often develop serious complications due to blood loss. Scientists, through biomedical research, have developed surgical techniques and other treatments for accident victims.
Scientists at Walter Reed Army Institute of Research in Silver Spring, Maryland, and the American Red Cross have developed a bandage loaded with dried, highly concentrated blood-clotting proteins that can halt even severe arterial bleeding within minutes. In animal tests, the bandage stopped previously uncontrollable bleeding in seconds. Human tests for the bandage are required before requesting approval from the FDA.
Diabetes is the third leading cause of death by disease in the United States. Each year, more than 600,000 people develop the disease and 34,000 die from it. Diabetes can cause blindness and kidney failure, and it doubles the risk of heart attacks and strokes.
Researchers have tested more than 50,000 natural and synthetic substances and have found a fungus compound that acts like insulin, raising the possibility that diabetics may be able to take pills instead of shots. This treatment, which is being tested in mice with diabetes, significantly lowers the sugar in animals’ blood.
Breast cancer is the sixth leading cause of death in women in the United States. In 2004, more than 188,000 people were diagnosed with breast cancer and morethan 41,000 people died from it. For years, scientists have searched for a genetic link for breast cancer. After four years of experiments, researchers have finally bred a strain of mice that indicates how a gene causes breast cancer.
Developing the first animal model to study the disease is the latest in a controversial, two-decade hunt for the breast cancer gene. Within months of the 1994 discovery of the gene, researchers began marketing a test that revealed to women in certain families whether they had inherited a higher-than-usual risk of developing breast and ovarian cancers.
More than 1 million people have HIV, the virus that causes AIDS, in the United States. Worldwide, more than 10 million people have contracted the disease, for which there is no cure. Scientists now say that the risk of contracting AIDS is no longer confined to a few high-risk groups.
AIDS researchers at Yerkes Regional Primate Research Center in Atlanta have been searching for answers and cures for the AIDS virus. Recent breakthroughs at the center look promising for protection against the disease. Scientists have created a DNA vaccine that protects monkeys against the HIV virus. Achieving protection with this vaccine is a promising step toward eradicating this deadly disease.
Researchers hope the first human trials of a substance that blocks cervical cancer could also help kill HIV. A topical solution, sodium dodecyl sulfate—an ingredient found in toothpaste and shampoo—kills human papillomavirus, the sexually transmitted infection that causes cervical cancer. The solution has also shown to be effective in killing HIV. Another potential treatment has come from the virus that causes feline AIDS. The new chemical was found to work against the human virus in test tube experiments.
At three pounds, the human liver is the body’s largest internal organ and is amazingly intricate, working to detoxify the blood and to make an array of vital proteins. Results of laboratory animal studies are providing new clues about how to prevent liver damage and giving researchers hope that they might be able to halt or even reverse the progression of liver cirrhosis. Experiments have involved two types of lab mice—regular mice and so-called "knockout" mice, which lack a gene necessary to produce interleukin-6 (il-6), an immune system component that has a number of functions, most notably to trigger inflammation. Scientists assumed that the knockout mice would fare better than their counterparts; instead, they discovered knockout mice had a death rate twice those that produced the il-6. While the discovery that il-6 is needed to combat liver cirrhosis looks promising, more experimentation is needed before the results can be used in humans.
Experiments with dogs and other animals have led to several breakthroughs for humans in combating heart disease. Most of what we know about cardiology—including open-heart surgery, which saves hundreds of thousands of lives each year—has come from studying animals. Now, studies show that a new drug may help in the fight against heart disease. Discovered at Harvard, endostatin has already proved effective in treating some cancerous tumors in mice. Now, the same drug has shown to slow the development of hardening of the arteries, also called atherosclerosis. The research raises the possibility that a new category of drugs, known as blood vessel inhibitors, may be useful against heart disease and cancer.
Animals have been useful in gene therapy, a relatively new method of combating several diseases. By isolating genes that cause the disease, gene therapy has been useful in discovering who may be at risk for certain diseases, including Parkinson’s disease and obesity.
Two research groups have discovered a gene known to suppress obesity and regulate how quickly the body burns calories. This find could be the first step in keeping people thin. Scientists have tested mice with and without this gene; mice with the mutated gene did not gain weight regardless of their diet.
Some researchers have isolated a group of bone-precursor cells from skeletal muscle, transferred them into a gene that fosters bone growth, and injected these genetically altered cells into mice. The results show that muscle-derived stem cells are capable of forming bones inside animals, leading physicians to deliver bone-producing cells to certain types of bone fractures.
Corrective genes were successfully delivered to certain brain cells of laboratory mice, saving them from dying of a simulated form of Parkinson’s disease and correcting some of their walking difficulties. The result is the latest example of experimental viral gene therapy, a technology attempting to cure a variety of diseases.
Scientists have also used a form of gene therapy to insert a gene for protein, called vascular endothelial growth factor, into the leg muscles of adult mice. The muscle cells create high levels of the growth factor, attracting new cells to the site and leading to the formation of major new blood vessel structures previously thought to exist only during the embryonic stage. The research suggests that stem cells can be used to build new vascular structures and blood vessels, which has applications in treating heart disease, diabetes, and preventing tumors.
More than 30 million people in the United States have some sort of hearing loss; of these, 2 million are almost totally deaf. Deafness affects development and ability to communicate. The disability costs $30 billion each year in medical costs, special education, and lost productivity. Researchers have used animals to discover the chromosome they believe responsible for certain types of congenital deafness in mice. In a study that is part of a larger project involving humans and animals, the researchers were able to produce a mouse that could hear. The researchers injected tiny bits of normal DNA into fertilized mouse eggs specifically bred to be deaf.
One out of four Americans has some sort of cancer, and researchers continually struggle to find cures for the various cancers that affect Americans. Cancer affects three out of four families and costs $70 billion each year in health care expenditures. Researchers are constantly searching for answers to this family of deadly diseases.
A new drug has been shown to cure human small-cell lung cancer in mice when taken in low doses. Initial data from preclinical studies showed the drug, used in non-curative doses and combined with chemotherapy, completely eliminated the animals’ tumors in 100 percent of the mice.
Mice have been used to discover how external factors affect your brain. Researchers think running could build up your brain. Mice that ran on an exercise wheel whenever they wanted created more new cells in one area of the brain thanmice that pursued other activities. The study followed up on previous work that found mice created more cells in the hippocampus, an area involved with memory and learning.
Spinal Cord Injuries
More than 500,000 Americans are hospitalized each year with traumatic brain and spinal cord injuries, which are the leading cause of death in children and young adults. Each year, 80,000 people are victims of spinal cord and brain injuries, and the health care costs equal $100,000 billion.
Scientists have used nose cells from pigs to regenerate and restore function to severed spinal cords in rats and primates. The procedure was successfully used on 25 to 50 rats whose spinal cords were surgically severed.