[Prediction of cardiac function deviations (ECG data) in the course of permanent cosmonaut's monitoring starting from selection till return to earth after short-duration space flight].

Analyzed were deviations in cardiac function in 29 cosmonauts with previous aviation and other occupations ranging of 29 to 61 y.o. who made 8- to 30-day space flights (totai number of flights = 34) between 1982 and 2006. The deviations were identified in ECG records collected during clinical selection, clinical physiological examination (CPE) before flight, insertion and deorbit in transport vehicles, and post-flight CPE. Based on the analysis, the cosmonauts were distributed into three groups. The first group (55.2% of the cosmonauts) did not exhibit noticeable shifts and unfavorable trends in ECG at any time of the period of observation. The second group (34.5%) showed some deviations during selection and pre-flight CPE that became more apparent in the period of deorbit and were still present in post-flight ECG records. The third group (10.3%) displayed health-threatening deviations in cardiac function during deorbit. These findings give start to important investigations with the purpose to define permissible medical risks and ensuing establishment and perfection of medical criteria for candidates to cosmonauts with certain health problems.

[Population genetic study of Russian cosmonauts and test subjects: genetic demographic parameters and immunogenetic markers].

Genetic demographic characteristics and immunogenetic markers (blood groups ABO, Rhesus, MNSs, P, Duffy, Kidd, and Kell) have been studied in a group of 132 Russian cosmonauts and test subjects (CTSG). Analysis of pedigrees has shown a high exogamy in the preceding generations: almost half of the subjects have mixed ethnic background. According to the results of genetic demographic analysis, a sample from the Moscow population was used as control group (CG). Comparison between the CTSG and CG has demonstrated significant differences in genotype frequencies for several blood group systems. The CTSG is characterized by a decreased proportion of rare interlocus genotypic combinations and an increased man heterozygosity. Analysis of the distributions of individual heterozygosity for loci with codominant expression of alleles has shown that highly heterozygous loci are more frequent in the CTSG. Taking into account that the CTSG has been thoroughly selected from the general population, it is concluded that heterozygosity is related to successful adaptation to a space flight.

[Role of age in +Gz and +Gx tolerance by female candidates to astronauts]. / Vliianie vozrasta na perenosimost' peregruzok +Gz i +Gx zhenshchinami pri otbore v kosmonavty.

Analyzed was the role of age in the tolerance of +Gz (up to 5 units) and +Gx (up to 8 units) by female candidates to cosmonauts on the stage of initial centrifuge selection in the years of 1979 through to 1993. Selection was made of 26 healthy non-flying women aged 23 to 39 who were divided into 4 groups with 5-year intervals. Female tolerance of g-loads and shifts in a number of physiological parameters during centrifugation were discovered to be age-dependent. The poorest tolerance of +Gz and +Gx loads was typical of women below 25 years, the best, at the age of 31 to 40 years. It was stated that tolerance of these demanding g-loads by women, especially below 30, was generally worse compared with men. There were also some distinctions in the cardiovascular response in women and men. These results point to the significance of centrifugation in selection female candidates to cosmonauts irrespective of their age.

[Dynamics of tolerance of +G loads by non-flying subjects: a longitudinal study]. / Dinamika perenosimosti peregruzok +G, litsami neletnykh professii pri dlitel'nom nabliudenii.

Selected cosmonauts-investigators may be held on wait for many years. The longitudinal health study is of great significance in the context of prediction of tolerance to various flight stresses. The purpose of this work was to investigate the tolerance to +Gz-loads during extended (up to 18 years) dynamic longitudinal study of 50 male cosmonauts and candidates of non-flying occupations by the data of 363 medical observation runs on a centrifuge with the radius of 7.25 m. Analysis of these data showed that 82 % of the subjects sustained good tolerance of G-loads and only 18 % of the subjects displayed its decrement or instability. A new proof received the data concerning better +Gz-tolerance by subjects aged 31-35 and less tolerance by the subjects younger than 30 and older than 46-50 years. The longitudinal study allowed to identify 4 types of G-tolerance variation, i.e., stable, relatively stable with individual drops down to decreased, non-stable with periodic drops, and a distinct trend towards a decrease. These investigations provided new scientific data about the dynamics of separate physiological functions during exposure to +Gz-loads resultant from longitudinal study of the same group of subjects, and allowed to make an expert prediction of shifts in the G-tolerance.

Effect of antiorthostatic bed rest on the human body.

Head-down (-4 degrees) bedrest brings about a more rapid development of changes in haemodynamics, fluid displacement and nervous tone than traditional recumbent bed rest. Changes occurring during head-down hypokinesia have much in common with the changes typical of real weightlessness. They are characterized by phasic changes in the vascular tone. Under these conditions changes in the tone and blood-filling of the brain are important for the functional state of the vestibular apparatus.