Volume 2

Advances in military medicine, made by American investigators / edited by E.C. Andrus [and others].

  • United States. Office of Scientific Research and Development. Committee on Medical Research.
Date:
1948
Catalogue details

Licence: Public Domain Mark

Credit: Advances in military medicine, made by American investigators / edited by E.C. Andrus [and others]. Source: Wellcome Collection.

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    indicated that actual deficiency would be unlikely to develop at this level of intake. On the other hand, when the subjects were on a daily intake of gi mg. of ascorbic acid and were exposed to an altitude of 18,000 feet with- out supplemental oxygen for one hour, three times weekly, a gradual depletion of ascorbic acid and a lowered concentration of ascorbic acid in the plasma were observed. The evidence indicated that the depletion resulted from increased utilization. Repeated exposures to the same altitude without supplemental oxygen did not affect the urinary output of thiamine, ribo- flavin, alpha-ketoglutaric acid, pyruvic acid, and acetone bodies. In another project, included in the program of research in aviation medicine, these investigations were extended with further studies on the effects of altitude, anoxia, and so forth on the excretion of electrolytes and 17-ketosteroids. In another project at Northwestern University, experiments were con- ducted to evaluate, in young men of military age, physical fitness and work- ing ability at high altitudes in relation to nutritional factors. Seven volun- teers were studied during a period of sixteen months with varying dietary intake and physical activity at ground level and at simulated high altitudes (15,000 feet) in a decompression chamber. The observations led to the con- clusion that these men could be maintained for considerable periods of time on a diet of 3400 calories with a daily average intake of 0.95 mg. of ribo- flavin and 0.85 mg. of thiamine without any evidence of physical deteriora- tion as measured by various types of tests performed at ground level and at high altitude. It was also shown that physical training at ground level greatly increased ability to perform work at a high altitude. Valuable bio- chemical data were collected on the utilization and excretion of the two vita- mins at different levels of intake. The significance of corneal vascularity in relation to possible combined effects of riboflavin deficiency and exposure to strong light was investigated in two projects, with mainly negative results. Because corneal vascularity is associated with riboflavin deficiency in experimental animals and in man and has been observed among men subjected to prolonged exposure to strong sunlight (for example, shipwrecked sailors and grounded air force per- sonnel), it was suggested that the two factors might be mutually aggravat- ing. In experiments conducted on rats at the Public Health Institute of the City of New York, there was no evidence that strong light decreased the riboflavin content of the cornea, and no difference was seen in the develop-. ment of corneal vascularization as a result of riboflavin deficiency in rats, exposed or not exposed to strong light. At New York University an inves-. tigator studied the effects of light on corneal vascularization and its relation: to riboflavin deficiency in men maintained on a diet of 1.5 mg. of riboflavin: daily and subjected to varying exposure to sky light and to light from a1 carbon arc lamp. There was no evidence of significant changes in corneal vascularity induced by such exposure. Investigations conducted by Butler and Gamble in Boston were planned: