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Biomedical subjects

A I Grigor'ev

Publications and source records attributed to A I Grigor'ev.

At least 19 recordsLinked to original sources
PubMed2006

[The influence of space flights on water-electrolytes turnover and its regulation].

A study of water-electrolyte exchange, the condition of water milieu of the organism, and the volume- and electrolyte homeostasis regulation in space flights, and also in postflight period has shown the important role of the water-salt homeostasis in adaptation of the human and animal organism to weightlessness. Obviously, downturn of food consumption, renal excretion and the intestine output seem to be caused by suppression of activity of mechanisms of ion deposition. The most intensive changes of the liquid milieu volumes occur in the first days of weightlessness or in its ground simulation. And, with prolonged duration, the changes of extracellular liquid volume and the volume of plasma do not extend. After termination of long space flights, activation of renin-aldosterone systems occurs as well as a decrease in efficiency of antidiuretic hormone, misbalance of pressor/unpressor prostanoids. In the period of re-adaptation after space flights, development of desensitization of kidneys to endogenous ADH occurs. This is the basis for researches directed to improvement of the existing scheme of correction of the hydrogenous status of the astronaut organism in the closing stage of flight.

Animals↗
PubMed2005

[To the question of the possibility of oral insulin administration].

The influence of oral insulin upon carbohydrate exchange in healthy volunteers was evaluated. One of the two forms of insulin used in the study was insulin, immobilized in a volume of polyacrylamide gel, modified by ovomucoid (proteolytic enzyme inhibitor), isolated from duck eggs; the other form was enteric-coated tablets bases on hydrogel substance. The oral administration of the hydrogel substance or the tablets resulted in the fall of blood glucose concentration by 34.9 +/- 4.4% and 28.6 +/- 6.9%, respectively. The maximal effect of the hydrogel substance and the tablets was observed at the 90th and the 180th minutes.

Administration, Oral↗
PubMed2005

[Low-deuterium water effect on transplantable tumors].

Such models of transplantable tumors as Lewis sarcoma, uterine sarcoma-322 and uterine carcinoma-5 were used to study possible inhibitory effect by low-deuterium water. Such water was given to experimental animals (20 mice in each group). Controls (30 in each group) received tap water with standard deuterium concentrations. Low-deuterium water treatment resulted in significant inhibitory effect on volume of all tumor patterns concerned: it delayed nodule formation at transplantation site. However, no increase in survival time was obtained.

Deuterium↗
PubMed2004

[The role of support afferents in organisation of the tonic muscle system].

Results of experimental studies are reviewed that point out to the leading role of the support afferents in control of structural-functional properties of the tonic muscle system. It is shown that the support afferents play a role of the trigger in the postural system, the trigger enhancing (when the support is present) or inhibiting (when the support is withdrawn) the activity of tonic motor units (MU's). Under the absence of support condition, recorded in extensors are: an obvious decline of the muscle stiffness and the maximal voluntary force; a significant decrease of the absolute force of the isometric contraction of single skin muscle fibers evoked by Ca++; a prominent decline of the tonic muscle fibers transversal size; and the transformation of the myosin phenotype from slow to fast one. Mechanical stimulation of the support zones of soles in the regimes of locomotion (slow and fast stepping) under the absence of support condition eliminates all the above effects.

Calcium↗
PubMed2003

[Antidiuretic reaction of the human and rat kidney to peroral administration of arginine-vasopressin and desmopressin].

Water in amount of 5 ml/100 g body weight was administered through a gastric probe into the stomach in alert rats; subjects-volunteers drank 20 ml of water per 1 kg of body weight. This resulted in diuresis at the peak of which the excreted water fraction reached 23% in rats and 12.4% in human subjects, whereas excretion of the osmotically free water amounted to 0.103 +/- 0.018 ml/min/100 g body weight and 10.0 +/- 1.8 ml/min/1.73 m2 of the body surface, respectively. These data indicate a practically complete inhibition of the arginine vasopressin secretion. On intragastric administration of 10 micrograms of arginine vasopressin or 0.2 microgram of desmopressin, with water in rats, a prolonged and quite obvious antidiuretic response occurred, with a marked increase of reabsorption of the osmotically free water in kidneys. A direct correlation has been found between the dose of the intragastrically administered vasopressin in the dose range from 0.1 to 10 micrograms/100 g body weight and a decrease of clearance of the osmotically free water. In subjects volunteers, an antidiuretic reaction to administration of 0.2 mg of desmopressin with water, was found. The data obtained provide a direct proof of intestinal absorption of nanopeptides without loss of their physiological activity. Significance of the data obtained for physiology of digestion and for clinical medicine, is discussed.

Administration, Oral↗
PubMed2003

[Problems of diagnostics and prophylaxis in a Martian flight].

In future interplanetary missions that will take up to two years the role of monitoring of the main human body systems and prevention of the effects of microgravity for the benefit of crew health and performance will rise eminently. In contrast to the orbital flights, diagnostics and prophylaxis will be a responsibility of the doctor within the crew who will consult solely own expertise and judgment. Hence, criteria and requirements to health monitoring and medicare systems and items are to be defined. The paper substantiates a concept and principles of diagnostics and prophylaxis, ideas concerning the scope of associated measures on the way to Mars, during the visit to the planet and on return to Earth; potentiality of a short-arch centrifuge as a means of prophylaxis is also discussed.

Diagnostic Services↗
PubMed2003

[Biomedical support to a piloted Martian expedition].

Review of the main problems of biomedical support (BMS) to a piloted mission to Mars has revealed a correlation of the BMS constituents and parameters with the specifics of this venture that makes it significantly different from the near-Earth flights. Success of the transit to Mars and back and safety of the planet explorers will hinge on the BMS system functionality in the harsh changing environment and power to ensure medical safety, health and performance of the crew. Particular emphasis has been placed on the necessity to enhance methods of crew selection and training, to develop an on-board medical center including an appropriate database, to search for high-efficiency countermeasures, to formulate prescriptions for resolution possible psychological problems in flight, and to design and manufacture regenerative life support and radiation protection systems.

Astronauts↗
PubMed2003

[Consideration of the deuterium-free water supply to an expedition to Mars].

Interplanetary missions, including to Mars, will put crews into severe radiation conditions. Search for methods of reducing the risk of radiation-induced cancer is of the top priority in preparation for the mission to Mars. One of the options is designing life support systems that will generate water with low content of the stable hydrogen isotope (deuterium) to be consumed by crewmembers. Preliminary investigations have shown that a decrease of the deuterium fraction by 65% does impart to water certain anti-cancer properties. Therefore, drinking deuterium-free water has the potential to reduce the risk of cancer consequent to the extreme radiation exposure of the Martian crew.

Animals↗
PubMed2002

[Regulation of the human cardiovascular system under microgravitation].

The paper presents the results of studies of the cardiovascular system and analyzes the mechanisms of regulation and adaptation of this system during long-term space flights. Special attention is given to the analysis of the homeostatic mechanisms for maintaining a number of integrative parameters of the cardiovascular system at the pre- and near-flight level and to the mechanisms of development of orthostatic detraining character after flights. How a new level of circulatory function in the absence of microgravitation is formed is shown.

Adaptation, Physiological↗
PubMed2002

[Certain principles of Mars mission crew life and the organization of the performance].

Article is devoted to some new aspects of biomedical support and countermeasures during a manned Mars mission. Significant differences in crew--Mission control interaction in a Martian and orbital flight are described. Special attention is paid to the problem of the Martian crew autonomy and decision-making. The authors give some practical recommendations for improvement of the space flight medical support system existing in Russia to meet the needs of a Martian expedition.

Astronauts↗