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N Pace

Publications and source records attributed to N Pace.

At least 55 records · Page 3Linked to original sources
PubMed1976

Body composition changes in men and women after 2-3 weeks of bed rest.

Several parameters of body composition were measured in eight men before and after 14 days of continuous recumbency, and in eight women before and after 17 days of recumbency. The parameters measured included body weight, body water, body potassium, plasma volume, and plasma protein concentrations. From these, values were derived for body fat content, lean body mass, body cell mass, and circulating plasma proteins. In general, the men and women responded similarly to continuous recumbency. Characteristically, there was significant reduction of plasma volume and body potassium in both groups. The women showed a significant reduction in circulating plasma protein, entirely in the albumin fraction; a similar change was observed in the men. The women, but not the men, showed a significant increase in circulating fibrinogen. Both men and women lost body cell mass, while body fat content remained the same or tended to increase slightly. It is expected that similar changes would occur in weightlessness. It is further concluded that women should tolerate the weightlessness of space flight physiologically as well as men.

Adaptation, Physiological↗
PubMed1975

Weight growth of colony-reared chimpanzees.

Body weight data, collected routinely from the US Air Force chimpanzee colony at Holloman AFB, was used for a longitudinal analysis of growth. Data were fitted to a model based on human growth patterns, which is described and compared to other treatments applied to growth data. Results are compared to other observations of chimpanzee and of human growth.

Age Factors↗
PubMed1975

Effect of 14 days of bed rest on urine metabolite excretion and plasma enzyme levels.

After one week of ambulatory baseline measurement, a group of eight men 19-26 years of age remained continuously recumbent for 14 days. Studies were continued for one week following the prolonged recumbency. Urine excretion rates for a number of constituents were determined 2 days before bed rest, on day 14 of bed rest, and day 6 after bed rest. Blood plasma samples were also obtained at these times, and analyzed for several enzymes. On day 14 of bed rest significant increases were observed in urine excretion of total osmotically active substances, magnesium, calcium, phosphate, creatinine, hydroxyproline, and 17-OH corticosteroids. A decrease occurred in urinary glucose excretion. Plasma levels of alkaline phosphatase and LDH-3 were depressed, while plasma GPT was elevated. Many of these changes persisted on day 6 after bed rest, and are interpreted as concomitants of the disuse atrophy of the musculoskeletal system that characterizes prolonged bed rest and weightlessness.

Adaptation, Physiological↗
PubMed1974

Metabolic responses of monkeys to increased gravitational fields.

A depletion of body fat has been reported by several investigators for various species of homoiotherms exposed to chronic acceleration. Generally the effect is proportional to field strength, and over the size range examined (0.25-5 kg) it becomes more severe in larger animals. There is some evidence that this may be the result of increased secretion of a pituitary hormone, the fat mobilizing substance (FMS). An exception to the defatting effect of chronic acceleration was observed in mature pig-tailed monkeys (Macaca nemestrina)--although they exhibited other changes generally found in homoiotherms exposed to hyperdynamic environments. It is considered that this unusual primate response to chronic acceleration may result from a different geometry of the central nervous system, and its effect upon gravity load distribution in the lower part of the brain.

Acceleration↗
PubMed1974

A monkey metabolism pod for space flight weightlessness studies.

An experiment system is described which will permit quantitative physiological studies in 8-14 kg adult monkeys during future space flight opportunities such as the NASA Shuttle. The system comprises a fiberglass pod containing a comfortable restraint couch for the animal. The pod is divided into upper and lower halves. When the monkey occupies the couch, a rubber belly-band forms a gas seal between the upper and lower portions of the animal. The upper-pod ventilating air stream monitored for PO2, PCO2, PN2 and PH2O to permit continuous metabolic gas-exchange measurements for computation of metabolic energy expenditure. The lower pod is lined with ashless filter paper for excreta collection and entrapment of liquid urine, and is ventilated separately. At the end of experimental periods of 1 to 7 days, all excreta plus the filter paper are removed for chemical analysis. The lower-pod ventilating gas ports also allow application of lower-body negative pressure to test cardiovascular competency when desired. The upper pod is provided with automatic food pellet and drinking water dispensers for quantitative measurement of nutrient intake. Balance assessment of the following elements can be made: N, Ca, P, Mg, K, Na, Cl, S and Fe. Animals have been kept in continuous restraint in the system for as long as 30 days without apparent ill effects.

Animals↗
PubMed1969

Biosatellite 3. Preliminary findings.

Physiological deterioration in the male macaque monkey flown in Biosatellite III necessitated its recall after 8.5 days of a planned 30-day flight. For the first 7 days the only telemetered signs of a progressive general decline were falling brain temperature and lowered central venous pressure, which occurred in the last 3 days of flight. Fluid loss in flight was high, caused initially by sweating and later by diuresis, and appeared to arise in redistribution of blood in visceral pools as a consequence of weightlessness. Death occurred suddenly 12 hours after the flight and was caused by ventricular fibrillation.

Animals↗