Characteristics of healthy population among the migrants to the North.

The goal of the study was to elucidate psychophysiological characteristics of subjects who can adapt effectively to Arctic and Subarctic conditions. Plasma cortisol and insulin levels, blood pressure as well as functional sensori-motor asymmetry have been examined in the groups of North Selkups and transit workers from the Subarctic regions. The highest level of plasma cortisol was observed in the Selkups with the predominance of the right indices of sensorimotor asymmetry, whereas the lowest cortisol concentrations have been found in the left-handed groups. The level of insulin appeared to be lower in all examined groups of the Selkups. No changes in the blood pressure were found among the northern populations. The maximum incidence of arterial hypertension was revealed among shift workers with the predominance of the right profile of functional asymmetry. The indices of functional asymmetry, giving important information about adaptive abilities of different populations to severe climato-geographical conditions, can be a useful prognostic factor for the professional selection of workers in the North regions.

[Adaptive dominance and functional asymmetry of brain]. / Adaptatsionnaia dominanta i funktsional'naia asimmetriia mozga]

Rapid environmental changes lead to formation of adaptive dominance which makes the body search for biologically appropriate reactions under the new conditions. This changes in fundamental properties of the brain, like memory, emotions, hemispheric functional asymmetry by ensuring optimization of the processing of a drastically increased flow of signals. The order of information processing is determined by its significance for the body. Selection of new and emotiogenic signals first activates by changes in cortical-subcortical relationships, the left hemisphere and the right hemisphere isolate new and emotiogenic information, respectively. Subsequent inversion of hemispheric dominance, i.e. the prevalence of right hemispheric functions provides construction of a new programme of the body's interaction with the altered environment. This may be possible as it is the right hemisphere that predominantly regulates emotional, humoral, and endocrine regulation. At this stage of adaptation, there is an increase in interhemispheric integration which eventually restores the initial interhemispheric relationships. The newly recovered dominance of the left hemisphere ensures not only an effective reproduction of the formed programme, but organizes a leading reflection of reality.

Relationships between left hemisphere predominance and disturbances of lipid metabolism in different ethnic groups.

The purpose of this study was to analyze the relationships between brain hemisphere predominance and disturbance of lipid metabolism in atherosclerosis in different ethnic groups. Three groups of subjects were examined: 52 healthy Selkups (the isolated ethnic population of the Far North), 50 healthy Russian men, living in Novosibirsk, and 78 Russian men, living in Novosibirsk, who had myocardial infarction before the age of 50. Blood cholesterol, low density lypoprotein (LDL) and high density lypoprotein (HDL) levels of the subjects with different brain functional asymmetry were compared. The lack of either hemisphere predominance is the most common among the Selkups. The population of Selkups as a whole showed low concentrations of cholesterol and LDL in comparison with both Russian groups. For all examined groups the pattern of lipid metabolism has been worsened for the subjects showing the left hemisphere predominance. The changes of lipid metabolism indices in subjects with the dominant left hemisphere is discussed.