Effect of hypokinesia and the combined action of gravitational load and hypokinesia on the structure of the hepatic portal system]

General hypokinesia during 1--6 weeks resulted in dilatation of the interlobular veins. sinusoids and central veins. The sequence of alterations corresponded to terms of hypokinesia. After exposure to "gravitation stress--hypokinesia for 1--6 weeks" stagnation in the portal system of the liver was less than after exposure to hypokinesia alone, but unevenness of lumens in the interlobular veins and sinusoids was more pronounced. The foci of the vessel spasm were determined. The signs of stagnation in the system of the portal vein and unevenness of the width of all the links of the portal bed were most pronounced after combination "hypokinesia for 1--6 weeks-- gravitation stress".     

Nutritional status and physical work capacity

The functional consequences of nutritional intake and resulting nutritional status are reviewed in terms of maximal oxygen consumption, physical work capacity, heart rate response to exercise, work productivity, and endurance at submaximal work loads. The results of both acute “laboratory” and chronic “naturally occurring” malnutrition are considered as well as the effects of dietary supplementation and recovery from previously existing undernutrition. Obesity and anemia are also treated as separate but related nutritional entities.     

Features of the response of human striated muscle fibers to hypokinesia combined with physical loading

Antiorthostatic hypokinesia for 30 days produces in human beings certain atrophic changes and decreasing metabolic level in both types of the skeletal muscle fibers, the metabolic activity being more decreased in the fibers of the II type. The physical loading of speed-power character does not prevent atrophy phenomena, nevertheless produces an increase of the metabolic activity in both types of the fibers. Changes of adaptive character, resulted from the physical loading, do not ensure a complete compensation of the negative hypoxic effect, especially in relation to contractile structures of the fiber.     

Prolonged hypokinesia and its influence on the tissues and vessels of the extremities in experiments]

The work describes the results of complex investigation of the state of the supporting-motor apparatus of extremities of dogs subjected to six-month-long restriction of motor activity and the following reparation during a month. Intravital rentgenological, anatomical, histochemical and electron microscopic methods were used. It was shown that continuous hypokinesia resulted in substantial alterations of the vascular bed in the macro-micro-ultrastructural level, disturbance of metabolism, focal reconstruction of tissues of the extremities by the type of natural death of ultrastructural elements without a following reparation. A one-month term appeared to be insufficient for reparation of structural disorders. Special attention was given to reactions of the vascular system. Signs of blood transport via extracapillary pathways from the arterial bed into the venous bed were noted.     

Effect of primary hypohydration on physical work capacity

Physical work capacity (PWC₁₈₀) was assessed with different levels of hypohydration in 25 heat-acclimatized male volunteers in hot dry (45°C DB, 30% RH) and hot humid (39°C DB, 60% RH) conditions equated to a heat stress level of 34°C on the WBGT scale. Heat acclimatization was carried out by exposing the subjects for 8 consecutive days in a climatic chamber with moderate work for two 50 min work cycles and 10 min intervening rest pauses. Acclimatization resulted in significant decreases in heart rate (27 bpm), oral temperature (0.8°C), mean skin temperature (1.2°C) and a significant increase in sweating rate (120 g h^–1 m^–2). Day-to-day variations in body hypohydration levels during heat acclimatization were not significantly different, although water intake was found to increase significantly from day 3 onwards when the subjects were in ad lib water intake state. The heat acclimatized subjects were then hypohydrated to varying degrees, viz. 1%, 2% and 3% body weight deficit, with moderate work in heat in the climatic chamber and after successful recovery from the effects of thermal stress and exercise; their physical work capacity was assessed individually. Physical work capacity was found to decrease significantly with hypohydration as compared to controls. The decrease was of the order of 9%, 11% and 22% in the hot dry condition and 6%, 8% and 20% in the hot humid condition with hypohydration levels of 1%, 2% and 3% respectively. The decrease was more pronounced during 3% hypohydration level under both heat stress conditions. This decrease was in spite of significant increases in maximal ventilation. However, the PWC₁₈₀ under the two heat stress conditions, when compared, did not reveal any significant difference. It was concluded that the heat stress vehicle did not adversely affect the physical work capacity. On the other hand, the decreases in physical work capacity were found to be closely related to the primary hypohydration level in heat-acclimatized tropical subjects.Abbreviations WBGT wet bulb globe temperature - bam beats per minute - YSI Yellow Springs Instrument - EKG electrocardiogram     

The modifying action of Sophora japonica and an antioxidant vitamin complex on acute radiation injury to the body]

In experiments with mongrel male rats exposed to whole-body gamma-radiation (7, 9 and 11 Gy) the radioprotective effect of enterally administered Sophora japonica and its combination with an antioxidant vitamin complex was investigated. The radioprotective agents applied were shown to produce a synergistic effect.     

The dosage thresholds for disordered physical work capacity in mice and rats following irradiation

Physical efficiency of mice and rats at early times following irradiation with doses of 35 to 200 Gy was estimated by the muscle endurance and motor coordination indices. A threshold nature of the effects was exhibited at high doses. For instance, as large as 40 Gy was the dose threshold at which stability in the accomplishment of the known operations was impaired; at 70-100 Gy, the accomplishment decreased down to 50% of the initial level, by the 2nd hour after irradiation, with the subsequent partial restoration; 200 Gy was the threshold dose at which the disturbances were irreversible. These values were also similar to those of the threshold doses at which clinical picture of the affection was changed.