[The electrolyte balance of the blood in dogs exposed to multiple +Gz overloads]. / Elektrolitnyi balans krovi sobak pri mnozhestvennykh peregruzkakh +Gz.

Experiments of the series were carried out using 7 noninbred dogs. In the first series, the animals were exposed to + GZ acceleration of increasing value once or twice a week during 5 months. Each exposure continued until distinct cardiac arrhythmias were seen in ECG. Two weeks after the onset of exposure the dogs displayed hyponatremia and higher K-Na coefficient and two months later they showed hyperkalemia and hypermagnesemia which led to a 1.5 G increase of acceleration tolerance. In the second experimental series, the animals exhibited a beneficial effect of hypermagnesemia on circulation parameters and frequency of cardiac arrhythmias in response to a single + GZ exposure. These observations have demonstrated that electrolyte balance plays an important part in the development of adaptation to sustained acceleration.

[Hypovolemic reactions of man and animals to exposure to +GZ load factors of increasing intensity]. / Gipovolemicheskie reaktsii cheloveka i zhivotnykh pri vozdeistvii peregruzok +GZ narastaiushchei intensivnosti.

Maximal variations of the circulating blood and plasma volumes after water load and/or exposure to increasing +GZ were investigated in manned and animal studies. The animal study demonstrated that the relative changes in the circulating blood and plasma volumes can be calculated using hematocrit or hemoglobin values. On the 2nd minute after exposure to increasing +GZ of up to 14.5 G the animals showed a decrease (by 11.7%) of the circulating blood volume which was primarily associated with plasma losses. The change was not appreciably modified by the use of an anti-G suit. In the manned studies the decrease was 5.9% during exposure to 7 G and 11% during exposure to 9 G with an anti-G suit used. These observations show that the acceleration duration and value play an important part in the mechanism of plasma filtration in response to an increase in the hydrostatic pressure.

[Adaptive and cumulative effects in the dog exposed to routine +GZ acceleration]. / Adaptatsionnye i kumuliativnye éffekty u sobak pri sistematicheskom vozdeistvii peregruzok napravleniia +GZ.

The development of adaptive and cumulative effects was investigated in 13 noninbred dogs regularly exposed to +GZ acceleration: Group I dogs were exposed 3 to 4 times a week for 2 months and Group 11 dogs were exposed 1 to 2 times a week for 5 months. The tolerance threshold was evaluated with respect to ECG abnormalities. The study of circulation reactions and acceleration tolerance threshold revealed the predominant development of adaptive changes that were more distinct in Group 11 dogs. Cumulative effects in the form of functional disorders of pulmonary vessels occurred in all experimental dogs but less frequently in Group II dogs. Morphological lesions of the lung tissue developed in Group I animals after 2 to 3 exposures and in Group II animals after 2 to 3 months, the incidence rate being lower in those latter. These findings suggest that adaptive and cumulative effects in response to regular exposures to threshold +GZ acceleration develop more or less in parallel.

[Incidence and nature of electrocardiographic disorders in the dog after single and multiple exposure to +Gz]. / Chastota i kharakter narushenii élektrokardiogrammy u sobak pri odnokratnom i mnogokratnom deistvii peregruzok +GZ.

Pathological changes of the ECG were examined in 10 adult dogs exposed to +Gz once a day or 3 times a day for three days a week during 2 to 12 weeks. In response to acceleration all of the dogs developed ECG changes. The frequency and level of these disorders were dependent on the acceleration magnitude and the health state that varied during repeated exposure. These findings were used to develop a 5-score scale for measuring ECG disorders and to identify phase changes in acceleration tolerance during repeated exposure to +Gz. It was also demonstrated that animals can be specifically trained to tolerate sustained and high acceleration +Gz.

[Biochemical shifts in the blood plasma of dogs in multiple G-load exposure]. / Biokhimicheskie sdvigi v plazme krovi sobak pri mnogokratnom vozdeistvii peregruzok.

For 3 months experimental dogs were exposed to +Gz acceleration applied 3 times a day for 3 days a week. The initial acceleration value was 8-9 G, then the parameter varied, depending on the tolerance limit which was evaluated with respect to heart rate disorders. Biochemical measurements showed the largest changes (decrease in total protein, increase in sugar, bilirubin, cholesterol, alkaline phosphatase and transaminases) after the first day of the repeated exposure to +Gz. Following 1-3 months of the exposure, the changes decreased significantly; however, the K+ concentration continued to decline and that of alkaline phosphatase continued to increase. The results obtained indicate the development of adaptation to repeated +Gz exposures which differs from that to short-term exposures.

[Characteristics of the course of pyrogenal fever in animals after prolonged hypokinesia]. / Ob osobennostiakh techeniia pirogenalovoi likhoradki u zhivotnykh posle dlitel'noi gipokinezii.

The experiments on rabbits with pyrogenal fever and amidopyrine injection have demonstrated that their 15- and 30-day exposure to hypokinesia produces changes in the reactivity of thermoregulating centers, their overexcitation and depletion. These changes are more distinct after 15-day hypokinesia.