ABSTRACT
Human brain in prenatal period is a most vulnerable to ionizing radiation body structure. Unlike atomic bombings or radiological interventions in healthcare leading at most to external irradiation the intensive internal exposure may occur upon nuclear reactor accidents followed by substantial release and fallout of radioactive 131I. The latter can lead to specific neuroradioembryological effects. OBJECTIVE: To create an experimental model of prenatal cerebral radiation effects of 131I in human and to determine the experimental and clinical neuroradioembryological effects.Study object. The neuroradioembryological effects in Vistar rats exposed to 131I in prenatal period. Nervous system status and mental status in 104 persons exposed to ionizing radiation in utero due to the ChNPP accident and the same in 78 not exposed subjects. METHODS: Experimental i.e. behavioral techniques, including the spontaneous locomotive, exploratory activity and learning ability assessment, clinical i.e. neuropsychiatric, neuro and psychometric, neuropsychological, neurophys iological methods, both with dosimetric and statistical methods were applied. RESULTS: Intrauterine irradiation of Wistar rats by 131I was simulated on a model of one time oral 27.5 kBq radionu clide administration in the mid gestation period (0.72±0.14 Gy fetal thyroid dose), which provides extrapolation of neuroradioembryological effects in rats to that in humans exposed to intrauterine radiation as a result of the Chornobyl catastrophe. Abnormalities in behavioral reactions and decreased output of conditioned reflex reactions identified in the 10 month old rats suggest a deterioration of cerebral cognition in exposed animals. Specific cog nitive deficit featuring a disharmonic intellectual development through the relatively decreased verbal intelligence versus relative increase of nonverbal one is remained in prenatally exposed persons. This can indicate to dysfunc tion of cortical limbic system with especial involvement of a dominant hemisphere hippocampus. Decreased theta band spectral power (4-7 Hz range) of cerebral bioelectrical activity in the left frontotemporal area is suggestive of hippocampal dysfunction mainly in dominant hemisphere of prenatally irradiated persons. Disorders of hippocam pal neurogenesis due to prenatal exposure by radioactive iodine can be a biologic basis here. Innovative approach es in social adaptation, psychoprophylaxis and psychorehabilitation involve the maximum effective application and development of just the most developed psychological and cognitive abilities in survivors.
Subject(s)
Chernobyl Nuclear Accident , Cognitive Dysfunction/physiopathology , Iodine Radioisotopes/administration & dosage , Maternal Exposure/adverse effects , Prenatal Exposure Delayed Effects/physiopathology , Radiation Exposure/adverse effects , Radiation Injuries, Experimental/physiopathology , Adult , Animals , Case-Control Studies , Cerebral Cortex/physiopathology , Cerebral Cortex/radiation effects , Cognitive Dysfunction/etiology , Cognitive Dysfunction/psychology , Conditioning, Classical/radiation effects , Embryo, Mammalian/radiation effects , Exploratory Behavior/radiation effects , Female , Humans , Limbic System/physiopathology , Limbic System/radiation effects , Locomotion/radiation effects , Male , Mental Status and Dementia Tests , Pregnancy , Prenatal Exposure Delayed Effects/psychology , Psychomotor Performance/radiation effects , Radiation Injuries, Experimental/psychology , Rats , Rats, WistarABSTRACT
OBJECTIVE: to evaluate the state of to assess the state of hematopoietic system of experimental rats according to the geno and cytotoxic effects in bone marrow and changes in morphology composition of peripheral blood caused by prolonged 131I intake. MATERIALS AND METHODS: Within 15 days sodium iodide with activity of 29,3 kBq/animal was daily orally administered to Wistar rats. At 1, 2, 3, 7 and 15 days specific radioisotope activity, level of micronuclei in bone marrow cells, cyto toxicity index, number of erythrocytes and leucocytes in peripheral blood were determined. RESULTS: It is established that the maximum genotoxic effect induced by 131I prolonged intake was formed at the early terms of observations followed by the reduction of cytogenetic damage in bone marrow cells of rats, while the cytotoxic effect of 131I was formed at the remote terms of administration. Changes in peripheral blood morphology were caused by left shift leukocytosis due to immature forms of neutrophils. In leucograms throughout the experi ment increased levels of lymphocyte atypical forms were observed. CONCLUSION: Prolonged administration of 131I to the laboratory rats does not cause dose dependent changes of cyto and genotoxic markers in the bone marrow and peripheral blood cells.
ABSTRACT
The chromosomal damage (micronuclei) of the peripheral blood lymphocytes of the group of professionals who had participated in the liquidation of the Chernobyl NPP accident and have continued their work at the "Shelter" and of the group of self-settlers who living for about ten year in the Chernobyl NPP alienation zone were studied. Residents of Kyïv were the group for comparison. It was found that in professionals the number of micronuclei was higher due to the presence of cells with several micronuclei while in the self-settlers it was due to the increase in the number of cells with one micronucleus. Also was determined the correlation between the frequency of micronuclei in the lymphocytes of the self-settlers on the one hand and the level of radionuclides contamination of territory and dose loading on the other.
