Biomedical subjects
Publications and source records attributed to S B Daniiarov.
Physiological parameters were studied at the 760 and 3200-metres altitudes in chemically desympathised (25 mg guanethidine per kg during 30 days) albino rats. Changes in external respiratory function were found to be less obvious at the higher altitude.
The hypoxic resistance of rats was found to change depending on the period of adaptation and different regimens of cerebral ischemia. The tonus and responsiveness of vegetative nervous system were found to increase in sympathetic nervous system and to decrease in parasympathetic one. Various parameters of cerebral blood flow in high altitude conditions were also studied in cats and humans.
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The effect of high altitude hypoxia on the sympathetic nervous system was studied on desympathized rats. The degree of the sympathetic ganglion neurons destruction and catecholamine fluorescence were determined. The investigation showed an increase of catecholamine fluorescence in sympathetic ganglia in high altitude adaptation. 30-day administration of sympatholytic guanethidine at high altitude results in destruction of less ganglion neurons than at low altitude. At high altitude the rate of fluorescence of biogenic amines in unaffected cells remains high. After partial desympathization (7 days), the rate of neuron destruction diminishes and biogenic amines fluorescence increases along with the duration of preliminary adaptation.
A design of dry spirograph is described. It is characterized by greater precision, lack of inertia, high reliability, absence of respiration resistance, adequate form of recording, rapid resetting to any respiratory rate. The device consists of two similar injection syringes, photoelectric sensor for the identification of the initial moments of respiration stages, electromagnetic valves, two photoelectric converters of the air volume into the impulse signal, vacuum micro-pump, microcompressor and a system of air-driving tubes. In the initial position of pistons and valves the microcompressor pumps air into the inhalation cylinder and lifts the piston to the upper extreme position. With the signal marking the beginning of inspiration, the valves switch over and the piston lowers, pushing out the air, which moves into the animals' respiratory organs. Simultaneously, the signals of the inhaled air volume from the photoelectric transducer reach the recorder. During expiration the air pushes the piston down into the second cylinder and photoelectric transducer gives the information on the volume of the expired air.
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In acute experiments on cats carried out in Frunze (at an altitude of 760 m above the sea level, control group) and at the Touya-Ashu high-altitude base (3200 m above the sea level, Central Tien Shan), resistography and extracorporeal vein reservoir were used to study the reactions of resistance and capacitance blood vessels of the small intestine to intraarterial injection of adrenaline (0.5, 5 and 10 micrograms). The reactions were studied days 3, 15 and 30 after the animals stay in the mountains. It was found that during adaptation to extreme high-altitude conditions, the animals showed significant changes in the reactivity of alpha- and beta-receptors of smooth muslce cells, with these changes being inconsistent in the resistance and capacitance compartments of the small intestine.
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In cats, i.a. administration of adrenaline (10 microgram), serotonin (30 microgram), and acetylcholine (10 microgram) on the 3rd, 15th, and 30th days of animals stay at 3200 m altitude induced different vasomotor responses in precapillary and postcapillary portions of intestine vascular net during different periods of high altitude adaptation. Changes of reactivity in different receptor structures of smooth muscles, the initial tonus of the small intestine resistance vessels associated with the whole adaptive rearrangement of the organism functional state in the high altitude extreme conditions, are the possible mechanisms of detected changes.
In studying hemocoagulation in dogs under conditions of Frunze (760 m above the sea level) and Tuya-Ashu (3200 m above the sea level) it was shown that in the "emergency" phase of adaptation (the first three days) there was seen activation of fibrinolysin and profibrinolysin with depression of antifibrinolysins and inhibitors of profibrinolysin activators. The concentration of plasma fibrinogen at that period decreased by 100 mg%, which could promote an increase in the vascular permeability and improvement of oxygen approach to the tissues. Later, along with elevation of fibrinolysin and profibrinolysin activators there was a marked increase in the level of fibrinolysis inhibitors. Correlation of all the fibrinolysis components was established at a new level.
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Mechanical activity of isolated papillary muscles in the left ventricle of rats was studied during permanent high altitude adaptation. The main computer parameters were: maximal developing tension, force of contraction, and capacity of papillary muscles at different periods of mountain adaptation (3, 15, 30 and 45 days). On the 15th day of mountain exposure, a statistically significant increase of maximal developing tension and papillary muscles activity was observed, which remained until the 45th day. Capacity was considerably increased on the 30th--45th day of adaptation. The data suggest positive effect of high altitude hypoxia on inotropic function of intact myocardium.
The amplitude of papillary muscles shortening at gradual increase of the rate of stimulation from 12 to 60, 120 180/min in conditions of permanent high altitude hypoxia on 3rd, 15th, 30th, and 45th day of adaptation noticeably increased at 180/min stimulation starting from the 15th day of mountain exposure and remaining till the 30th and 45th day. The performance of the muscles had been considerably decreased as compared with the control tests, on the 3rd day of adaptation.
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The development and outcome of radiation disease were studied on dogs kept at an altitude of 3200 m above sea level. Clinical observations, morphological examinations of blood and bone marrow and measurements of blood coagulation parameters were carried out at different time intervals. Our findings demonstrated that irradiation of animals that followed a 25-day altitude acclimatization and their subsequent exposure to an altitude alleviated radiation disease. The clinical course of radiation disease aggravated in dogs that were reacclimatized to highlands after irradiation. It can be postulated that the dogs kept in highlands before and after irradiation developed a more intensive process of restoration, especially of erythropoiesis. They also showed a stable decrease of the blood coagulation rate and long persistence of high fibrinolytic activity of the blood.
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