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Filter by:Data on transgenerational effects following nuclear accidents are important for understanding fully the consequences of parental exposure to ionizing radiation. Few studies to date have had adequate statistical power to detect effects of the magnitude expected based on animal data, and most have not been of low-dose, protracted exposures associated with nuclear accidents and their aftermath. Although, to date, scant use has been made of the new genomic technologies, in Chernobyl-exposed areas of Ukraine and Belarus, excess minisatellite mutations have been seen in children born after the accident. We propose a study of parent-child trios in which at least one parent was exposed to Chernobyl radiation as a clean-up worker (mean dose >=100 mGy) and/or evacuee from a contaminated area (mean >= 50mGy). The specific aims are to investigate the transgenerational and de novo mutation rates of the spectrum of genetic variants in trios, in particular looking at effects in children and mapping them to possible parental origin of the chromsome. Together with long-term collaborators at the Research Center for Radiation Medicine (RCRM) in Kiev, epidemiologic data will be collected for up to 450 trios of parents with preconceptional doses and their unexposed offspring. We will use state-of-the-art genomic technologies to characterize the landscape of the genomes of the trios to determine whether parental radiation exposure is associated with genetic mutations transmitted to the offspring, by examining de novo mutation rates, minisatellite mutations, copy number alterations, and variations in telomere length. The analysis will be conducted in peripheral blood and/or buccal samples (when blood is not available) from complete father-mother-child trios. Doses to the gonads from the time of the accident to the time of conception will be reconstructed for all parents using existing records supplemented by interview data. Trio subjects will be selected from representative populations exposed to radiation from Chernobyl who are under active follow-up in the Clinico-Epidemiologic Registry at RCRM. To help identify specific effects of paternal and maternal radiation exposure, we will initially select sets of trio subjects in five categories: (1) exposed father, unexposed mother; (2) unexposed father, exposed mother; (3) both parents exposed; (4) both parents unexposed; and (5) a group of high dose emergency workers with acute radiation syndrome. All trio members will be invited to the RCRM outpatient clinic for collection of a 20 ml blood sample (or buccal cells for those who refuse phlebotomy). Both parents will be asked to complete a general questionnaire to obtain demographic and lifestyle data. Then one or both will complete detailed dosimetry questionnaires, based on forms used in previous collaborations with RCRM and administered by specially trained interviewers. Once 50 trios have been recruited (10 from each of the 5 exposure categories), we will conduct an interim evaluation of participation rates, sample collection and quality, and dose reconstruction in order to modify the protocol as needed. The analytical approach will be to correlate the extent, especially for de novo events of genetic alterations in the offspring with parental preconceptional radiation dose overall and by parental origin. The statistical power in relation to de novo mutations is very high, in excess of 90%, but somewhat lower for trends in minisatellite mutations. Study findings will contribute importantly to knowledge of the heritable effects of moderate- and low-dose radiation exposure in humans and to radiation risk projection. Eventually data from the Trio Study may be shared with the international community through dbGap.
Background: - Previous research has shown that a person s genes can influence how they respond to alcohol. But researchers do not yet know all the genes that might be involved. Objectives: - To identify genes that are related to how non-alcoholic individuals respond to alcohol. Eligibility: - Healthy people between 21 and 30 years of age who have no history of alcohol or drug dependence. Design: - The study requires one or two 9-hour visits to the National Institutes of Health Clinical Center. - Participants must not take any medicines (except birth-control pills for women) for at least 3 days before the visit. They must not drink alcohol for at least 2 days before the visit. - Screening includes a medical history, physical exam, and a urine test for drugs of abuse. - Participants will be given alcohol over about 2.5 hours. This will have about the same effect as having three to four drinks. Frequent breathalyzer tests will check breath alcohol level during the infusion. - Before and during the infusion, participants will complete questionnaires about mood and feelings. Other tests will study thinking, balance, judgment, and risk-taking. Blood samples will be collected four times during the infusion. - Participants will have breakfast at the start of the visit (around 8:00 AM). They will have a snack before the start of the alcohol infusion (around 10:45 AM). Lunch will be served after the alcohol infusion is complete (around 2:20 PM). After the tests, those in the study will have to stay in the Clinical Center until their breath alcohol level falls below 0.02%. This can take up to 2.5 hours. A final blood sample will be drawn at that time. Participants will not be able to drive themselves home after the study visits. Also, they should not take any medicines or operate any machinery for at least 2 hours after leaving NIH.