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Biomedical subjects

G P Stupakov

Publications and source records attributed to G P Stupakov.

18 recordsLinked to original sources
PubMed1989

Microgravity-induced changes in human bone strength.

A decrease of spongy tissue strength of iliac bone has been identified in healthy men under conditions of simulated weightlessness (bed rest). Countermeasures have significantly prevented this decrease. Additional investigations have indicated probability of degenerative-destructive bone change development under conditions of usual human activity as a consequence of bone strength decrease.

Animals↗
PubMed1975

[Bone strength in hypokinesia].

Experiments (20- and 100-day) on rats showed that decrease of the animal motor activity with preserved static function of the extremities led to a marked thinning of the cortical layer of the femoral bone. However, the ability of the whole bone to bear mechanical load decreased but slightly. An increase in the firmness of the bone tissue as a result of its mineralization compensated for the cortical layer thinning.

Animals↗
PubMedDate not supplied

[The use of the optimal control method for correcting lipid metabolism].

The paper discusses an optimal artificial control of lipid metabolism which is the most important element of human life. The fact that the solution of this problem contributes to a decrease in risk of developing some diseases in the pilots and cosmonauts and an increase in human adaptive potentialities is particularly emphasized. An approximated algorithm of solving an assigned model problem and the results of computational experiments are presented.

Aerospace Medicine↗
PubMedDate not supplied

[Changes in the mechanical properties of the femur and jaws in dogs with osteoporosis due to a single acute whole-body irradiation].

The authors studied the condition of the mineral component and the mechanical properties of different parts of the femur and jaws in 27 dogs; 12 of these dogs were exposed to a single acute total irradiation by a dose of 4.0 Gy. The development of osteoporosis and diminished firmness of the femoral spongy structures were revealed: no marked changes occurred in the cortical bone tissue due to the relative inertness of its metabolic structures. Signs of osteoporosis were found in the region of the frontal and masticatory teeth of the mandible.

Acute Disease↗
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

[Possibilities for pharmacological correction of regional osteoporosis in an unsupported extremity].

In 20- and 40-day rat studies the prophylactic effect of retabolil and calcitrin (calcitonin) against hypodynamics-induced osteoporosis was investigated. Hypodynamics was produced by surgical amputation of the lower third of the leg and hence by loss of the support function of the limb. Retabolil was injected intramuscularly at a dose of 0.2 ml once a day for 10 days and calcitrin was injected subcutaneously at a dose of 2 units MRC in 0.5 ml distilled water once a day. The results indicate that osteoporosis in the supportless bone of the experimental animals and that seen during space flight developed in a similar way. In the experiment retabolil and calcitrin inhibited the progressive development of osteoporosis but the strongest effect was obtained upon a combined application of the two drugs.

Amputation, Surgical↗
PubMedDate not supplied

[Change in the properties of the femoral bones of rats due to exarticulation of the crus and hypokinesia].

Rat experiments demonstrated that unilateral calf exarticulation leading to the loss of the leg weight-bearing function resulted in a decrease of the density, ash content and mineral content in the femoral diaphysis. This manipulation reduced the mechanical strength and did not change the elastic properties of the bone. Histological examinations showed osteoporosis in the cortical plate. Partial maintenance of the weight-bearing function in the animals with bilateral exarticulation of the calf prevented these changes. The results suggest that special steps taken to provide static load on leg may be effective countermeasures against atropic changes in bones devoid of their weight-bearing function.

Amputation, Surgical↗
PubMedDate not supplied

[Significance of the vibration component in the injurious action of impact acceleration].

Animal experiments demonstrated that damped oscillations of the support construction induced by impact accelerations enhanced their damaging effect on dogs. Within the frequency range tested--from 20 to 178 Hz--the threshold of lesions of the lungs, heart and liver decreased and reached 34% at a frequency of 85 Hz. The level of liver lesions was inversely proportional to the frequency of the support oscillations. Lesions of the lungs and the heart were more expressed at 85 Hz and decreased with an increase or a decrease of the oscillation frequency. At a frequency of 130--176 Hz the effect of the vibration component was not seen.

Acceleration↗