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Biomedical subjects

C Allen

Publications and source records attributed to C Allen.

At least 217 records · Page 12Linked to original sources
PubMed1979

State of unesterified fatty acids in skim milk.

By a multiple extraction procedure the unesterified fatty acids of skim milk have been shown in at least three entities: a) free dissociated and undissociated fatty acids, b) fatty acids associated with the membrane material in skim milk, and c) fatty acids of unknown origin requiring acidification to pH 1.5 for extraction.

Animals↗
PubMed1979

Photodegradation of riboflavin in milks exposed to fluorescent light.

Photodegradation of riboflavin in 50-ml samples of fluid milks exposed to fluorescent light (2690 lux) followed first-order reaction kinetics, and the reaction rate (s-1) averaged 1.86 x 10(-5) in skim milk and 1.47 x 10(-5) in whole milk. Additional evidence led us to conclude that photodegradation of riboflavin proceeds prior to the appearance of a light-induced off-flavor.

Animals↗
PubMed1978

Vasopressin in the rat with spontaneous hypertension.

Because vasopressin is one of the most potent naturally occurring pressor agents, and because of its importance in the regulation of blood volume and composition, we have undertaken a study of the role of vasopressin in the pathogenesis of the hypertension in the Okamoto-Aoki spontaneously hypertension (SH) rat. In SH rats, systolic blood pressure increased from 135 +/- 3 (SE) mmHg at age 33 days to 184 +/- 3 mmHg at age 75 days (P less than 0.01). In the Wistar-Kyoto (WKY) control rats, blood pressure increased from 100 +/- 2 to 120 +/- 2 mmHg (P less than 0.01). The differences in blood pressure between the SH and WKY rats at all ages were significant (P less than 0.01). During the age period 33-75 days, the 24-h urinary excretion of vasopressin in the SH rat was consistently more than twofold greater (P less than 0.01) than in the WKY rat. Plasma vasopressin concentration and pituitary vasopressin content were also elevated in the SH rat (P less than 0.01 and P less than 0.02, respectively). Changes in systolic blood pressure in the SH rat, however, were not paralleled by changes in the urinary excretion of vasopressin. The data indicate that the secretion of vasopressin is elevated in the SH rat. However, the magnitude of this elevation, in and of itself, may not be sufficient to account for the rising blood pressure in the young SH rat.

Animals↗
PubMed1977

Loss of body weight and fat during exercise in a cold chamber.

Ten men spent one week in a cold climatic facility performing a simulated arctic military exercise demanding an energy expenditure of 13-16 MJ-day-1. Although the ration pack was adequate, extensive plate wastage led to a negative energy balance of 2.2 MJ-day-1. Fluid intake was also insufficient, with a 3.25% decrease of body weight, and a 9.7% decrease in skin thickness over the cold exposure. Extensive fat mobilization was indicated by a decrease of skinfold thicknesses, an increase of body density, and associated ketonuria and glycosuria. The fat breakdown far exceeded the calculated energy deficit, and it is postulated that much of the "surplus" energy was required for synthesis of additional muscle protein. In the arctic environment, both energy and fluid balances are better maintained because there are few distraction from the simple pleasure of preparing and eating meals.

Adipose Tissue↗
PubMed1977

Treatment of obesity by exercise in the cold.

Six obese men aged 25 to 46 years exercised vigorously for 3 1/2 hours in a cold chamber (-34 degrees C) on 10 successive days. There was an early water loss of about 1 kg, probably due to mobilization of glycogen stores, and a subsequent fat loss of about 4 kg (as estimated from readings of skinfold thickness and confirmed by underwater weighing). The total fat loss was much greater than the calculated external energy deficit (as estimated from dietary records, an activity diary and use of a Kofranyi-Michaelis respirometer). Although some energy was "wasted" through ketosis, much of the additional energy was apparently used for synthesis of additional muscle protein. Both readings of skinfold thickness and underwater weighing indicated that the loss of adipose tissue was well sustained in the first 2 months after the exercise program. Further experiments are recommended to determine whether cold exposure makes a specific contribution to the observed weight loss, and whether this approach would be equally effective in a larger and less selected sample of obese patients.

Adult↗
PubMed1977

LaTulippe--a case study of a one hundred and sixty kilometre runner.

A 55 year old runner covered 160 km within a 20 hour period. His speed averaged 8.16 km/h, at an estimated 59.1% of maximum oxygen intake. After the first four hours of running, one of five fluids was taken in rotation every twelve minutes. Volumes ingested whe heart rate for the final four hours (125/min) was not increased relative to oxygen consumption for this portion of the run. Constancy of heart rate, continued urine production and formal fluid balance calculations all indicate that hydration was well maintained over the run. Caloric intake averaged 480 kcal/h (2.01 MJH), being greatest fro the ice-creas/syrup mixture; the energy deficit (56/KA/H, 235 kJ/h) was small during that part of the run in which food was provided.

Blood Pressure↗
PubMed1977

Loss of body fat during an arctic winter expedition.

Fifty-five soldiers have been observed over a vigorous 10-day sledging patrol in the Canadian arctic and subarctic. Initial observations showed a low level of physical fitness (26% body fat, aerobic power 41.9 +/- 7.8 ml kg-1 min-1, handgrip force 43.7 +/- 7.2 kg). Over 2-week northern sojourn, energy expenditures as measured by a Kofranyi-Michaelis respirometer and diary observation averaged 3248 kcal (13.6 MJ) day-1, with a small (152 kcal (633 kJ)) positive daily energy balance. A weight loss of 1 kg, presumably water, was made good within 1 week of return to the south. A fat loss of some 3.9 kg was probably attributable largely to the demands of lean tissue synthesis. The lean mass was increased by 3.9 kg over the trial, with parallel gains of muscle force and aerobic power. The rapid mobilization of depot fat led to marked ketonuria.

Adipose Tissue↗