View clinical trials related to Disease Susceptibility.
Filter by:Parkinson's disease (PD) occurrence is higher in rural than in urban populations of industrialized countries. Epidemiologic and human tissue studies suggest that pesticides may be responsible for causing dopaminergic cell death at increased rates. While many pathophysiologic pathways may be involved in the neurodegeneration responsible for PD, genetic factors are likely to determine a general susceptibility to neurodegeneration.
This study will measure and compare hormone levels in women with catamenial epilepsy (epilepsy in which seizures are more frequent during menstrual periods), women with seizures not related to their menstrual cycle, and normal control subjects. It will determine whether there are differences among the three groups in their hormone levels or in how fast the levels change. It will also examine what relationship, if any, exists between hormone changes and seizures in women with catamenial epilepsy. The hormones under study include the gonadal hormones estrone, estradiol and progesterone, and the neuroactive steroids allopregnanolone, pregnenolone, and dehydroepiandrosterone. Women who meet the following criteria may be eligible for this 3-month study: - Between 18 and 45 years of age, with catamenial epilepsy - Between 18 and 45 years of age, with seizures, but not catamenial epilepsy - Between 18 and 45 years of age, without seizures All participants will have a physical examination at the beginning of the study, at each clinic visit, and at completion or withdrawal from the study. In addition, they will undergo the following procedures: Baseline Monitoring For the first 2 months, all participants will keep a diary of their temperature and onset of menses. Women with epilepsy will also record their seizures. Electroencephalography (EEG) Healthy volunteers will have a 45-minute EEG (recording of the electrical activity of the brain) at the beginning of each menstrual cycle and each day during the menses. Women with epilepsy will have continuous EEG monitoring for 8 days, beginning 5 days before their menstrual period is expected. The continuous monitoring can be done on an outpatient basis, using a portable EEG recording device, or as an inpatient, with admission to the hospital for the 8 days of recording. Blood Sampling All participants will have a small blood sample (2 teaspoons) drawn once a day on days 10, 14, 17, 19 and 21 of their menstrual cycle and three times a day on day 6 and for a period of 8 days, starting 5 days before the expected menses and continuing for 3 days of the next cycle. For the days with three blood draws, a small needle that can stay in place for up to 72 hours will be placed in the arm to avoid the discomfort of multiple needle sticks.
This study will explore whether different forms, or variants, of genes are related to a person s risk of developing breast cancer. The genes that are looked at have no clinical significance today, and thus will not impact your personal healthcare at this time. However, these results may help researchers better understand why some people develop breast cancer and others do not. The study will try to determine: if people with breast cancer have different gene variants from people without the disease; if these genetic differences influence a person s susceptibility to breast cancer when they are exposed to certain environmental substances, such as nicotine and estrogen; and if breast cancer that occurs in families is related to a grouping of these variants. The study will also look for certain proteins, cells, or other substances in fluid aspirated (by the use of gentle suction; no needles) from the nipple that might represent a pattern, or "fingerprint," indicating increased risk for breast cancer. Study participants will complete questionnaires on cancer risk factors, diet, and family history. A small blood sample (3 tablespoons) will be drawn for study of genetic differences between people with breast cancer and people who are cancer-free. Nipple aspirations, a noninvasive method to obtain fluid from a women s breast, will be attempted 4 to 6 times, over a 4 6 week period. For this procedure, the subject places a warm moist towel over the breasts for about 20 minutes. The breasts are then cleansed with a rubbing alcohol pad. The subject compresses the breast with both hands and a small plastic cup is inverted over the breast. Suction is applied to a small syringe (no needles) attached to the cup for about 15 seconds. The procedure may be repeated up to 5 times on each breast. Any drops of fluid obtained from the nipple will be collected in a glass tube. ...
Type 1 diabetes mellitus is an autoimmune disease in which the body's immune cells attack the insulin-producing cells of the pancreas. Several environmental and genetic factors may predispose individuals to developing this disease, including changes in a gene called CD152. This study will examine how this gene may influence the development of insulin-dependent diabetes. Patients with Type 1 diabetes mellitus enrolled in clinical trials at the National Institutes of Health and at the University of Florida and healthy normal volunteers may participate in this study. Participants will have up to three blood samples drawn over a period of less than 1 year. The first sample (about 20 milliliters, or 4 teaspoons), will be examined for changes in the structure of the CD152 gene. If the CD152 structure is different from that normally seen in the general population, a second sample (about 90 ml, or 6 tablespoons of blood) will be drawn. This sample will be used to study the function of specialized immune system cells (T cells), including their growth and survival, chemicals they produce when stimulated, and other factors. If these cells function differently from what is generally seen in the population, a third sample (90 ml) will be drawn for more detailed studies. This investigation may help explain what makes certain individuals susceptible to Type 1 diabetes mellitus and may contribute to the development of improved treatments for the disease.
We propose to test, by DNA linkage analysis of family pedigree members, the following interrelated hypotheses: 1) that sexual orientation is genetically influenced; 2) that the development of Kaposi's sarcoma and other outcomes of HIV infection in male homosexuals is affected by host susceptibility genes, circulating sex hormone levels, or HLA haplotype; and 3) that alcoholism and other psychobehavioral conditions are associated with homosexuality on a genetic basis and/or influenced by candidate behavioral loci. The subjects for these studies will be self-identified male and female homosexual probands and their relatives from families in which there are at least two individuals with homosexual orientation. All subjects will be adults, and will be referred through NIH physicians, private practitioners, and gay and lesbian organizations. Subjects will undergo a sexual orientation and behaviors interview, a psychiatric interview, and phlebotomy for HIV testing, HLA determination, endocrine measurements, and preparation of DNA from cultured lymphocytes. The DNA samples will be analyzed for a series of genetic markers that span the human genome and for candidate loci chosen for function.
Part I: To determine the pharmacokinetic dose for atevirdine mesylate ( U-87201E ) when used in combination with zidovudine ( AZT ). To determine the pharmacokinetic profiles of U-87201E and AZT over a 12-week period. Part II: To determine whether or not decreased viral susceptibility to U-87201E develops when the drug is administered concomitantly with AZT for 12 weeks. Part III: To evaluate the pharmacokinetic effects of ddI/AZT/U-87201E therapy and to assess changes in viral susceptibility to U-87201E. Interest exists in the development of antiretroviral agents that possess different mechanisms of action from nucleoside analogs such as AZT. U-87201E is a non-nucleoside reverse transcriptase (RT) inhibitor that has demonstrated activity against HIV-1; however, an emerging characteristic of non-nucleoside RT inhibitors is the development of rapid resistance to HIV isolates. Whether this resistance can be prevented in the presence of nucleoside analogs such as AZT and ddI has yet to be determined.