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Biomedical subjects

V S Kazeĭkin

Publications and source records attributed to V S Kazeĭkin.

6 recordsLinked to original sources
PubMedDate not supplied

[Effect of simulated weightlessness on calcium metabolism and the condition of bone tissue in experimental animals].

Male rats of the Wistar strain were for 40 days exposed to hypokinesia and hypodynamia. After exposure bone biochemical, physical, chemical, morphological and strength parameters were investigated. Both simulation studies led to changes in calcium and phosphorus metabolism but the nature of bone changes was different. It is concluded that the efficacy of drugs used as countermeasures in animal simulation experiments should be assessed by both exposures, viz. small size cages and suspension, because they reproduce different mechanisms of potential bone lesions in microgravity. It is also inferred that various countermeasures should be used in combination to yield the best results.

Animals↗
PubMedDate not supplied

[Low-gravitational changes in the bone system].

This review surveys reported data and observations made by the present authors concerning the effect of real and simulated hypogravity on bones of man and various animals. Bone biomechanics and mechanisms of osteodystrophic changes in hypogravity are discussed. Based on published data about bone metabolism regulation, the concept of bone formation and degradation in normal gravity and hypogravity is advanced. The conclusion is made that hypogravity-induced changes obey regulation at different levels, with local mechanisms being predominant. It is emphasized that a detailed investigation of every component of this process may become an important contribution to space and clinical medicine.

Aerospace Medicine↗
PubMedDate not supplied

[Evaluation of the changes in the bone structures of the human axial skeleton in prolonged space flight].

Changes in the mineral content of the left heel bone of the Salyut-6 crewmembers who made 75--184-day flights were measured by direct photon absorptiometry. The postflight results were compared with the predicted rate of bone atrophy. This parameter was derived from the data concerning variations in the mineral content of spongy bones of men and animals exposed to actual and simulated weightlessness for various time intervals. The efficiency of countermeasures against the adverse effect of weightlessness on bones was assessed. It is concluded that crewmembers with a high content of minerals in spongy structures of the axial skeleton and a low basal metabolism should be selected for prolonged space missions.

Atrophy↗
PubMedDate not supplied

[General patterns of bone atrophy in the absence of a weight load on the skeleton].

The rate of atrophic changes in spongy bones of the weightless man was estimated, using studies of human, dog and rat bones, as well as observations of neurological patients bed-stricken for a long time. Taking into consideration data on the literature on the bone status and mineral balance in real and simulated space flights, two models were built. The models make it possible to estimate osteoporosis of spongy bones of the axial skeleton in the absence of weight loading. One of the models--an intraspecies model for the human population--is based on the experimentally found rate of the physiological rearrangement of various spongy bones. The other--interspecies--model is built with reference to the parameters determining the rate, i. e. bone density and metabolism. The average monthly rates of axial bone losses calculated by means of the two independent methods are essentially identical. The data obtained allow prediction of the decrease of tolerance to head-to-feet impact acceleration as a function of flight duration.

Adult↗