Aviat Space Envir Md
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The effects of saline or atropine injection (2 mg, im) on eccrine sweating and performance time in seven healthy male subjects were evaluated during treadmill walking (1.34 m X s-1) in a hot-dry environment (Ta = 49 degrees C, Tdp = 20.5 degrees C) before and after heat acclimation (HA). Mean skin temperature (Tsk), rectal temperature (Tre), and heart rate (HR) were continuously measured. Sweat loss from the skin (Msw) was calculated by changes in body weight. ⋯ The change in Tre X min-1 (delta Tre/delta t) was lower (p less than 0.05) in atropine-injected subjects following heat acclimation, and their worktime was improved by an average of 23.5 min (p = 0.08). These data demonstrate that heat acclimation improves the endurance time of atropine-treated subjects in a hot-dry environment. This improvement was, in part, due to the potentiation of sweat gland activity enabling greater evaporative cooling for the same dose of atropine.
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Aviat Space Envir Md · Apr 1984
Comparative StudyCoagulation and fibrinolytic responses to exercise and cold exposure.
This study examined the effect of acute cold exposure on coagulation (PTT) and fibrinolysis (ELT), and the effect of cooling on subsequent exercise-induced coagulation and fibrinolytic responses. Ten male volunteers were tested at 5 degrees C and 28 degrees C on alternate days. Each subject began by sitting quietly for 60 min. ⋯ ELT was shortened to 74, 62, and 44% while HCT increased to 107, 107, and 111% of pretest values for CR, NE, and CE, respectively. No significant change was noted for PTT. It is concluded that acute cold exposure as well as exercise stress results in an increase in ELT activity of blood; simultaneous enhancement of the coagulation status of the blood in response to stress is not inextricably linked to an elevation of fibrinolytic activity, a result that questions the importance of the Hageman factor dependent pathway between coagulation and fibrinolysis.
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Although acute mountain sickness (AMS) has been studied for well over a century, a standard measure or index of the degree of illness for use in experimental research does not exist. This paper outlines a definition and procedures for an operational measurement of AMS using the Environmental Symptoms Questionnaire (ESQ). After 58 men completed over 650 ESQs during a stay of 1-3 weeks atop Pike's Peak (4300 m), factor analysis produced nine distinct symptom groups, with two factors representing AMS. ⋯ Signal detection theory was used to establish a criterion score value for each factor. Standard deviation values were used to derive indices of sickness severity. Discussion is given to the possible relationships between the two types of AMS and the more serious conditions of cerebral and pulmonary edema.
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Aviat Space Envir Md · Nov 1983
Transdermal scopolamine in the prevention of motion sickness: evaluation of the time course of efficacy.
This study evaluated the time course of efficacy of transdermal scopolamine in the prevention of motion sickness induced by exposure to coriolis stimulation in a rotating chair. We measured levels of efficacy, quantified side effects and symptoms, and determined inter- and intra-subject variability following use of transdermal scopolamine. The response to transdermal scopolamine was highly variable, although overall we recorded a 40% improvement (p less than 0.05) in test scores 16-72 h after application of the transdermal system. ⋯ The improvement was not due to the artifactual repression by scopolamine of selected symptoms of motion sickness. An unexpectedly high incidence of side effects was reported. It was concluded that the therapeutic use of transdermal scopolamine be evaluated individually and that individuals be cautioned that subsequent usage may not always be effective.
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We report a case of cerebral air embolism caused by pulmonary barotrauma in a diver. Severe neurological symptoms, deterioration during decompression, and a prolonged, complicated, initial pressure profile indicated the need for saturation therapy. Few clinical cases treated by saturation recompression therapy (SRT) have been reported since its introduction in 1978 (1,5). SRT is an effective alternative for the management of complicated and persistent accidents involving intravascular bubbles.