Elemental hair profile of the population is adequate hygienic indicator reflecting the impact of climatic and geographical, biogeochemical and ecological characteristics of the area on human. This indicator is also a tool for monitoring the population's health through detection and elimination the elementosis which is typical for the territory. The purpose of this study was to carry out a study of element status of adult population of the Republic of Tatarstan not employed in the manufacturing sector in the framework of the Federal Target Program "National System of chemical and biological security of the Russian Federation. It was analised elemental composition of hair 2,127 adult residents (1,667 women and 460 men aged 25-50 years) of the Republic of Tatarstan in the period 2004 and 2010 to perform the tasks. ICP-AES and ICP-MS methods was used. Mathematical processing of data was carried out using methods of nonparametric statistics. In general, the evaluation of the element status of population of the Republic of Tatarstan showed that the situation with the adult residents is sufficient, although the male part of the population deficits are relatively frequent. Attracts attention common for both men and women accumulation of aluminum, silicon and calcium in hair. The positive facts necessary to carry a small risk hipoelementosis frequency in women.
It is shown that the geometric mean of survival time and the deviation of ~ from x are measures of a population's resistance to acute hypoxia; that a measure of the individual resistance of an animal to such hypoxia is Student's parameter for that animal; that the distribution of Student's parameter in a population is a lognormal distribution under any conditions; and that the number of animals with low resistance is always equal to the number of highly resistant animals. The procedure described makes it possible to limit the number of animals used in an experiment by recording with the requisite accuracy the proposed measures of resistance to acute hypoxia at the population and individual levels. Key Words: hypoxia; resistance; individual resistanceKnowledge of individual variations in physiological parameters is necessary for defining the limits of age-and sex-specific variabilities in these parameters, the normal ranges of various responses, and the reserves of adaptive/compensatory mechanisms. The course of any disease is largely determined by individual responsiveness, which is based on congenital and acquired traits. As found in studies of responses to oxygen deficiency, there are individuals in any population of animals that survive when most of the test animals (even 95%) have died [2,3]. Animals differing in susceptibility to hypoxia exhibit substantial differences in behavioral, physiological, and metabolic variables [4,5].Although several methods are now available for quantifying the results of experiments on animals with acute hypoxia [1-3], these methods are not without their shortcomings. Linear estimates are valid only when variations in the recorded parameters are small. Different procedures may yield discrepant resuits depending on the empirical coefficients used. Department of Normal Physiology, Russian University of Peoples' Friendship, MoscowA relatively accurate method of linear analysis was proposed by Berezovskii [3] for rats separated, according to survival times at an altitude of 11,000 m, into groups with low, medium, and high resistance to hypoxia, using 30% deviations from the arithmetic mean of survival times calculated for all the rats tested over the same period as cutoff points for their separation into these groups. The cutoff points were set at equal intervals from the mean survival time and were shifted accordingly when its arithmetic mean changed. Berezovskii's method yields normal results if the deviations of survival times from the arithmetic mean are not large, whereas in the case of a nonlinear distribution where the minimal value differs from the maximal by one order of magnitude, this method produces a considerable deviation of the mean value from the center of the distribution curve.The aim of the present study was to identify, by means of a strict mathematical analysis, criteria by which the resistance of an animal population to acute hypoxia can be characterized as completely as possible.
The correlation between the pattern of a neuron's reaction to acute hypoxia and individual resistance to oxygen deficit is studied on rats in vivo as well as on surviving slices of their cerebellum in vitro. According to the survival time in a pressure chamber simulating an altitude of 11 km all the rats were divided into groups of high resistance, medium resistance, and low resistance to hypoxia. Survival time was 4.2 times longer in the high resistance group than in the low resistance group. I n the cerebeUar slices of high resistance animals 61.5% high-resistance neurons and 38.5% low-resistance neurons were recorded. On the other hand, in the high resistance animals the percentage of highresistance neurons and low-resistance neurons was 31.2 and 68.8, respectively. The period of hypoxia development was 4.32 tLrnes longer in the high-resistance neurons as compared to low-resistance neurons. It is speculated that individual differences in the resistance to O: deficit are of a hereditary nature and manifest themselves not only on the level of the whole organism, but also in the individual nerve cell. Key Words: hypoxia; individual resistance; neuronsIt is known that during acute oxygen deficiency the first to be affected is the central nervous system, and hypoxia resistance, according to Palladird [10], is defined not by the vulnerability of liver cells but rather by the sensitivity of neurons. The selectivity of nerve cell damage in hypoxia was first described by C. and O. Vogt [13], who introduced the term "pathoclisis', attributing the individual susceptibility of neurons mostly to specific features of vascularization and possibly also of nervous tissue metabolism. Later the same conclusions were r e a c h e d by other investigators [9,11,12,14]. A nonuniform pattern of response of neurons from different regions of the hippocampus to increasing hypoxia has been detected [8]. The Department of Normal Physiology, Russian People's Friendship University, Moscow existence of a correlation between the resistance of an individual organism as a whole and of an individual nerve cell to hypoxia remains an open question.The goal of this work was to study the relationship between the response of individual neurons in surviving brain slices and of the organism as a whole to increasing hypoxia. MATERIALS AND METHODSThe experiments were carried out on alert male white rats and their surviving cerebellar slices of 300-400 g thickness. In order to determine the individual resistance to hypoxia the animals were "raised" in a pressure chamber to an altitude of 11 km at a rate of 150-200 m/sec. The resistance was estimated by the survival time (ST) at a given
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