Effects of certain anaesthetics on plasma metabolite concentrations in the baboon (Papio ursinus).

Four groups of 12 baboons each were sedated for a period of 3 hours by means of one of 4 anaesthetic treatments. The treatments involved repeated administration of either ketamine or phencyclidine, or initial sedation with one of these followed by pentobarbitone. A number of plasma metabolites were measured at 30 min intervals. With one exception, there were no significant differences between the 4 individual anaesthetic treatments; there was a small, but significant, decrease in plasma calcium (3.4%) in the group receiving phencyclidine followed by pentobarbitone. There were, however, significant changes with time. Plasma inorganic phosphorus and magnesium concentrations in all the groups rose similarly, reaching mean respective increases of 21.8% and 7.7% after 3 hours. In a number of cases divergent time trends were observed between the pair of groups given pentobarbitone and the pair receiving only ketamine or phencyclidine. Pooling the results from each of these pairs of treatment groups doubled the overall group sizes to 24 animals each and enabled significant differences between the divergent time trends to be detected. In the former pair plasma zinc increased (by a maximum of 16.1%) and protein decreased (by a maximum of 4.0%), while in the latter pair alkaline phosphatase and cholesterol levels both increased (up to maximums of 7.8% and 5.2%, respectively). No significant changes with time were found to be attributable to diurnal variation. Some of the changes in plasma metabolite concentrations following anaesthesia are such that due care should be exercised in their determination and interpretation in anaesthetised baboons.

Effect of Ionizing Radiation on Ascospores of Three Strains of Byssochlamys fulva in Apple Juice.

Radiation inactivation of the ascospores of three strains (M 68-79), NRRL 1125 and NRRL 2614) of the heat resistant mold Byssochlamys fulva suspended in apple juice, was investigated. Whereas the ascospores of strain M 68-79 were significantly more sensitive to ionizing radiation, those of strains NRRL 1125 and NRRL 2614 did not differ significantly from one another in this respect. High numbers of ascospores of the more resistant strains required an absorbed dose of approximately 7.2 kGy (95% confidence interval 6.7 to 7.9 kGy) for inactivation; a decimal reduction dose (D10) of approximately 1.2 kGy was estimated for these strains. Ascospores of strain NRRL 2614 were confirmed as more radiation resistant when a small proportion survived an absorbed dose of 5 kGy and spoiled apple juice within a 3-month storage period. Although it was possible to inactivate B. fulva ascospores at absorbed doses of <10 kGy, it is probable that flavor impairment of apple juice, as well as cost currently limit the feasibility of this process.

The effect of differing dietary calcium and phosphorus contents on mineral metabolism and bone histomorphometry in young vitamin D-replete baboons.

Young baboons were fed semisynthetic, vitamin D-containing diets differing in calcium and/or phosphorus content over a 16 month study period. Diets low in calcium alone or low in both calcium and phosphorus led to the development of radiologic rickets and histologic features of osteomalacia at both 8 and 16 months. The diet which was low in calcium but which had a normal phosphorus content was associated with histologic features of hyperparathyroidism at 16 months; such features did not develop in animals fed the low calcium, low phosphorus diet. Biochemically the low calcium, normal phosphorus diet was associated with a transient fall in serum calcium around 8 months, and a more persistent elevation in serum phosphorus and alkaline phosphatase values during the latter half of the study. These biochemical changes were not seen in the baboons on the low calcium, low phosphorus diet. These results confirm that histological changes can occur as a result of dietary calcium deprivation in vitamin D-replete animals.

Exacerbation of rickets and osteomalacia by maize: a study of bone histomorphometry and composition in young baboons.

Three groups of young baboons were fed for 16 months on one of three diets. The first group was given a well-tried semisynthetic formula, the second group the same diet save that vitamin D had been omitted, and the third group was given the vitamin D-free diet in which maize replaced the dextrin normally used. Although both groups fed the vitamin D-free diets developed rickets and osteomalacia, the group receiving maize did so far more rapidly and to a much greater degree of severity, as evidenced by clinical, radiological, biochemical, and histological signs. The mechanism by which maize acts remains unclear, but this report serves to emphasize the extremely detrimental effects that might be expected in populations who are deficient in vitamin D and who have predominantly cereal diets.

[Initiation of a cure for kwashiorkor patients using a whey milk product. A comparison with cows milk]. / Inisiasie van herstel by kwashiorkor-pasiënte d.m.v. 'n weimelkproduk. 'n Vergelyking met beesmelk.

Whey milk, a side-product of cheese production, is not utilized for human nutrition. Whey protein is of good nutritional quality with a high biological value, exceeding that of whole-milk protein. A whey milk product consisting of liquid whey milk 60%, whole cow's milk 40% and skimmed milk powder 0.5% was mixed, spray-dried and prepared in instant form. After reconstitution with water, it was compared with sterilized whole cow's milk for the initiation of cure in 30 acute kwashiorkor patients randomly allocated to the two feeds. The diets were given for 3 weeks. There were no statistically significant differences between the two diets with regard to weight gain or levels of serum albumin, globulin, calcium, phosphorus, alkaline phosphatase, sodium, potassium, chloride, bicarbonate, urea or haemoglobin. Judging from this limited investigation, whey milk deserves consideration for human utilization. Should economical production be possible, it could contribute towards preventing and treating protein energy malnutrition.

Effects of plasma ascorbic acid levels on heat acclimatization in man.

Thirteen male volunteers were heat acclimatized for 4 h/day for 10 consecutive days. Three to four hours before each heat exposure, four of the subjects received an oral dose of 250 ascorbic acid, five received 500 mg ascorbic acid, and the remaining four a placebo. Rectal temperature, heart rate, and sweat rate were measured hourly during exposure. Venous blood samples were collected before each administration of drug or placebo. On days 1, 2, 3, 5, 8, and 10, blood samples were also collected just prior to heat exposure and after two and four hours of exposure. In the subjects receiving ascorbic acid, total circulating plasma ascorbic acid increased over the first three or four days to a plateau level some fourfold higher than in the subjects receiving the placebo. The plateau level was the same in the subjects receiving 250 mg and 500 mg ascorbic acid. The increased ascorbic acid concentration was shown to be associated with a reduction in total sweat output, independent of rectal temperature, and a reduction in rectal temperature, independent of total sweat output. The results indicate that ascorbic acid may be effective in reducing heat strain in unacclimatized individuals.

Effect of ascorbic acid on rate of heat acclimatization.

There is some indication in the literature that ascorbic acid (vitamin C) may reduce the physiological responses to heat stress. Consequently, the effect of ascorbic acid ingestion on heat-strain indicators has been studied on a group of 60 mining recruits undergoing climatic room acclimatization. Of the 60 men, 19 received a daily dose of 250 mg ascorbic acid; 21 a daily dose of 500 mg ascorbic acid; and 20 received a placebo daily. Measurements of rectal temperature, heart rate, and hourly sweat rate were made on all subjects during the 4 h of heat exposure per day for 10 days. The wet bulb temperature was 32.2 degrees C, the dry bulb 33.9 degrees C, the air movement 0.4 m/s, and the work rate 35 W. The results indicate that the rate and degree of acclimatization, as assessed by 4th-h rectal temperature, is enhanced by ascorbic acid supplementation and that no differences in response could be shown between daily dosages of 250 and 500 mg of vitamin C.