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Biomedical subjects

D V Vorob'ev

Publications and source records attributed to D V Vorob'ev.

9 recordsLinked to original sources
PubMed1998

[Dynamic changes in the reactivity of the hormonal system regulation with the impact by LBNP sessions in long-term space mission].

Experiment INTERSTITIUM was performed on days 3, 170, 287, and 430 of the long-term MIR mission of the Russian cosmonaut-physician in order to evaluate reactivity of the system of hormonal regulation of homeostasis during LBNP sessions. Data of the experiment displayed different types of reaction of the volume controls to LBNP at the onset (F-3), in the course of and soon after recovery (R-4) from the extended mission which are signs of specific phases of adaptive shifts in the organism of cosmonaut. Exaggerated reactivity of the hormonal systems during LBNP in flight suggests more significant consequences of the test for the cardiovascular system of human in microgravity. The most expressed hormonal reaction to LBNP was documented at the very beginning of the postflight period. Plasma cGMP was materially reduced in the process of the mission and remained quite low on R-4; return of nucleotides to the norm was observed no earlier than on R-90. Complete recovery from the space mission took three months when the hormonal reaction to LBNP was same as prior to launch.

Hormones↗
PubMed1997

[Effect of 120-day antiorthostatic hypokinesia on the reproductive function in women].

Original data on the peculiarities of adaptation to and functional status of the reproductive system in long-term antiorthostatic hypokinesia (AOH) have been obtained. The studies involved eight healthy female volunteers aged 26-37 years who were exposed to the head-down tilt (-6 degrees) for 120 days. The test subjects were divided into 2 groups of 4 persons each. In Group A, the countermeasures, i.e. physical exercise and pharmacological means, were used. In Group B, at no time did the test subjects use the countermeasures throughout the 120-day AOH. With and without the countermeasures, hypokinesia was found to impact the female reproductive system developing clinical symptoms of deficiency of the menstrual lutein phase and giving rise to small inclusions of functional fluids in the ovaries. Within 6 months after AOH, the ovarial function of the test subjects was fully recovered which may be indicative of the functional character of changes. These changes can be explained by dissociation of the functional relations in the hypothalamo-hypophyseal-ovarial system manifested by increases in the plasmic concentrations of luteinizing hormone (LH) against normal levels of follicle-stimulating hormone (FSH) and prolactin, and moderately increased levels of testosterone, relative hyperestrogenemia and hypoprogesteronemia. These clinical and hormonal developments are contrary to the observations usually made in various models of stress. Similarity of the hormonal profiles under hypokinesia and long-term immersion of female swimmers may be ascribed to common mechanisms underlying the disturbance of the reproductive function.

Adaptation, Physiological↗
PubMed1997

[Biological techniques in space].

The review is dedicated to the biotechnological studies in space. The main directions of studies in the space biotechnology are the developments of life support systems, crystallogenesis of biological macromolecules, separation of proteins and cells with the help of electrophoresis as well as the studies of cellular, subcellular and molecular processes induced by the spaceflight factors effect. The experience gained in the cultivation of unicellular organisms, the selection of perspective species and strains of microorganisms, the use of them in the ecological life-support system under development is considered in detail. The development of tooling designed for performing the overall technological chain ranged from growing the cell cultures to isolating the individual macromolecules and their storage has been followed. Findings gained in the studies of the transmittance of genetic material in the microorganisms allow one to hope that in perspective the microgravity conditions will be capable of cultivating the highly effective strains of the producers.

Aerospace Medicine↗
PubMedDate not supplied

[Averaging results of site recognition can increase the accuracy of annotating the human genome].

A systemic approach is proposed, which makes it possible to increase the accuracy of recognition of functional sites in arbitrary DNA sequences. The approach is based on the Central limit theorem and consists in the averaging of a large number of recognitions of a particular site. To obtain a rather large number of recognitions within the framework of conventional methods of recognition, consensus, and frequency matrix, 20 novel oligonucleotide alphabets were used. The approach was used to study the binding sites of GATA-1 and C/EBP transcription factors. It was found that the averaged recognition of these sites is more precise than each of specific recognitions, which just follows from the Central limit theorem.

Base Sequence↗
PubMedDate not supplied

[Effectiveness and mechanisms of the protective action of sidnocarb in experimental weightlessness and cooling].

Twenty-one subjects took part in experiments with acute cooling (maximally allowable time for swimming in ice-cold water and two-day exposure to winter field conditions) or two-day exposure to microgravity (simulated by water immersion). They were divided into a placebo group (5, 5 and 6 man-exposures) and a sydnocarb group (6, 6 and 4 man-exposures) and examined by biochemical, radioimmune and radioligand methods. It was found that physiological responses to cold and microgravity effects as well as sydnocarb were similar. During cold exposures the thermal steady-state was achieved by taking maximum daily doses of the drug. In thermoneutral water immersion body temperature fall was controlled by therapeutic doses of the drug. Body temperature decline beginning with immersion day 2 can be related to the endogenous decline of heat production due to a new functioning level which is well known in gravitational physiology, i. e. this is the effect of microgravity per se. With respect to old and new information about the pharmacological properties of sydnocarb, mechanisms of its high thermoregulatory effects on CNS structures responsible for heat production and heat loss are discussed.

Body Temperature Regulation↗
PubMedDate not supplied

[Glucocorticoid receptors in physiological states and in extreme conditions].

This review discusses glucocorticoid hormone--receptor interaction in the animal and human organism in the normal, extreme (stress, radiation, head-down tilt, etc.) and pathological situations. Particular attention is given to advanced lines of research into glucocorticoid receptors within the framework of space biology and medicine. It is stressed that the data about glucocorticoid receptors may form the key that can help better understanding of changes induced by exposure to the space environment.

Animals↗