Biomedical subjects
Publications and source records attributed to I G Popov.
Medical aspects of crew safety and life support as well as biomedical investigations form part and parcel of the preparation and conduct of manned space programs. The list of biomedical problems related to these programs is very long. The present paper concentrates on some of them.
This paper presents the measurements of free amino acids in the plasma of the Salyut-5 crewmembers (the second expedition) before and after their 21-day space flight. The measurements were performed in a Hitachi KLA-3B automatic amino acid analyzer. The changes in amino acid metabolism were associated with the chemical composition of the space diet, actual food intake and space flight effects. The conclusion is made that the dietary content of cystine and methionine, as well as phenylalanine, tyrosine, glycine, glutamic acid and serine should be increased. No signs of hepatic or renal dysfunction were detected. It is recommended to control strictly food consumption inflight.
Using the results of studying the body mass, carbohydrate, amino acid, nitrogen and mineral metabolism, as well as the general health status of test subjects who were on a low-caloric diet of 300 g chocolate, it is concluded that, although their condition and nutritional status remained satisfactory, chocolate in the above quantity can hardly be viewed as an ideal emergency food for pilots. The conclusion is based on the metabolic and operational limitations of chocolate. The study was carried out in a temperate climate with water consumption of no more than 11 per day.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A 90-day experiment has shown that a number of toxic gaseous contaminants are released into the atmosphere as a result of storage of mixed food wastes. The microorganisms dwelling upon decaving food wastes include different microbial species from the environment and food products. A preserving agent consisting of a mixture of quinosole and salicylic acid (1:1) has been used. The agent inhibited microbial activity and terminated processes of decay. This was indicated by a decline in the concentration of ammonia and amine compounds. In the presence of the agent fermentation processes, on the contrary, continued and increased.
This paper reviews published data concerning the protective function of skin and discusses factors that may affect its bactericidal capability, including space flight factors that are known to reduce its protective effect. Various concepts of the mechanisms of the bactericidal function are discussed. It is shown that in an enclosed environment the species composition of the resident autoflora and pH value of the skin of an essentially healthy man may change. The qualitative composition of the water-oil film as a source of nutrition and a skin microflora environment is discussed. Its effect on the autoflora composition and localization in various skin areas and, consequently, on the bactericidal capability of different skin areas is described. The skin bactericidal function results from an interaction of various factors that should be taken into consideration when developing flight-oriented hygienic requirements because space flight induces changes in the skin status.
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.
This paper presents physiological and hygienic evaluations of the food supply of Salyut-7 crews in normal conditions, simulation and actual flights of various duration (211, 150, 237, 165 and 126 days). The examinations have shown that the diets used have provided satisfactory health conditions and good nutritional status of the crewmembers.
The factors responsible for the formation of hydrogen sulphide in the water reclaimed from the atmospheric condensate were investigated. It was found that hydrogen sulphide developed in reclaimed water due to microorganisms which in the presence of inorganic sulphur (sodium thiosulphate) acquired the capacity to produce hydrogen sulphide, although normally they are not sulphur reducing. Among the microorganisms studied, E. coli showed the highest capacity (100%) and Streptococcus faecalis and Citrobacter freundii showed the lowest capacity (10-20%) to produce hydrogen sulphide.
The skin of healthy men kept in an enclosed environment was examined. It was found that exposure resulted in increases of the secretions of the sebaceous glands and sebum cutaneum, number and size of comedones, lipolytic activity of microorganisms, concentration of comedonogenic acids and skin irritating acids. It also caused a greater risk of papular and pustular rashes. Changes in lipid metabolism were consistent with the skin clinical state as well as with the subjective sensations of dirty skin, desquamation and itching. The severity of the above changes was correlated with the pretest physiological and hygienic status of the subjects.
Progress in the adequate nutrition of pilots during long-term flights since 1935 is discussed. Special attention is given to the arrangement of meals inflight. The nutritive value of the flight rations and methods of maintaining high quality of diets inflight are described. The hygienic estimate of diets and their efficiency is given. Attention is paid to the development of the main method of nutrition in long-term flights--diets consumed by pilots with an oxygen mask on. Nutrition in high altitude flights is discussed. The development of flight diets from "sandwich rations" (1935-1958) to up-to-date food products and polyvitamins (since 1958) is described. Further pathways for the study and improvement of flight rations are outlined.
The concentration of 17 free amino acids in plasma of 6 test subjects, aged 20, who were for 7 days exposed to head-down tilt and remained on a controlled diet, was measured. The study revealed an increase in the concentration of most amino acids by the end of day 3 and all amino acids by the end of day 7. This indicates that the diet used is a good source of the required amino acids and that there are processes which facilitate an increase of amino acids during the first days of exposure. The concentration of most amino acids returned to the baseline level on the 7th recovery day.
The hygienic approaches to daily meals for the flying personnel while on the ground are discussed from the historical point of view. It is indicated that the hygienic requirements for the chemical composition of the daily diet are related to the physiological norms accepted by the nutritional science in the USSR and other countries at various stages of its development. It is shown that the present-day diets for the flying personnel are of high caloric value. The basic physiological and hygienic requirements for the daily diets are given.
The content of valine was measured in plasma of 6 healthy male test subjects who were either on a normal or Salyut-5 space diet for 30 days. The measurements were performed with the aid of a Hitachi KLA-3B amino acid analyzer. Unlike other studies, blood samples were withdrawn every 5 days. The results suggest that the postflight decrease of the valine content is associated with the food composition. This makes it necessary to improve the amino acid composition of space diets and the technology of their manufacture. The foodstuffs used in the recovery period should be supplemented with amino acids, particularly valine, to compensate for enhanced anabolic processes.