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Biomedical subjects

H Fisher

Publications and source records attributed to H Fisher.

At least 109 records · Page 6Linked to original sources
PubMed1978

The antihypercholesterolemic activity of candicdin as a function of dietary cholesterol in cockerels.

In the first of two experiments using White Leghorn cockerels, a multifactorial analysis of variance was employed to characterize the antihypercholesterolemic responses (AHC) to candicidin (a heptaene macrolide antifungal antibiotic)-containing diets and the manner in which hypercholesterolemic challenges of different magnitudes modify these responses. In hypercholesterolemic diets, oral candicidin reduced plasma cholesterol concentration in a dose-dependent manner. The relative AHC effects of the diet were dependent on and varied directly with the presence and magnitude of the hypercholesterolemic challenge. The AHC effects of oral candicidin appeared to be additive to the homeostatic mechanisms limiting the rise in plasma cholesterol concentration induced by hypercholesterolemic diets. In the second experiment the absorption of oral 14C-candicidin was studied. Radioactivity above background levels was not found in any of the sampled tissues 4 days after administration of the 14C-candicidin pulse. The total cumulative recovery of radioactivity in the excreta was approximately 95% of the administered dose after 4 days. Within the limits of detection, oral candicidin did not appear to be absorbed from the intestine and appeared to be rapidly and quantitatively eliminated from the body in the feces. Chronic provision of candicidin appeared to increase transit time through the gastrointestinal tract.

Animals↗
PubMed1977

Marijuana exposure in vivo and human lymphocyte chromosomes.

Sequential chromosome examinations of peripheral lymphocte cultures were carried out on 21 adult male volunteers who smoked natural blend marijuana cigarettes containing about 1%, 2%, or no delta9-THC. For a limited number of subjects, blood samples from a single venipuncture were cultured independently in two cytogenetic laboratories, and later the slides were exchaged for re-analysis. There were significant differences between laboratories in the absolute break frequencies recorded. These inter-laboratory differences were demonstrated for both techniques of cell culture and metaphase analysis. Neither laboratory found a statistically significant increase in break frequencies asssociated with marijuana smoking. The present study, therefore, failed to detect a measurable effect of marijuana smoking on chromosomal aberrations in subjects experienced in the use of the drug.

Adult↗
PubMed1977

Nitrogen retention in rats fed on diets enriched with arginine and glycine. 1. Improved N retention after trauma.

1. Nitrogen retention was measured in adult rats (250-350 g) subjected to the trauma of hind-leg fracture and given diets with or without arginine plus glycine supplementation. Observations were also recorded on excretion of creatine, creatinine, allantoin, and orotic acid. Liver and skeletal muscle transaminase activities were also determined. 2. When traumatized rats weighing approximately 250 g were given a diet with 200 g casein/kg, supplemented with 20 g arginine and 10 g glycine/kg (EC diet) or a casein diet made isonitrogenous with the EC diet by addition of aspartic acid (C diet), a 60-70% increase in N retention was observed for the first 5 d post-injury for animals consuming the EC diet. A soya-bean (S) diet, isonitrogenous to the diet containing 20% casein, supplemented with arginine and glycine was as effective as the EC diet in promoting significantly better N retention of traumatized rats (350 g) in comparison to rats given the C diet. 3. When the dietary casein content was reduced to 100 g/kg, supplements of 10 g arginine and 5 g glycine or 20 g arginine and 10 g glycine/kg did not improve N retention. It is suggested that both protein quality and protein quantity are important following injury. 4. An increased excretion of creatine was observed in traumatized rats given the high-protein diets supplemented with arginine and glycine. No consistent changes were noted for urine creatinine. 5. 5. Urine allantoin levels remained stable after leg-fracture in rats consuming either the C or EC diets. Differences in the levels of urine orotic acid were found during both the pre- and post-injury periods in rats given the C, EC or S diets. 6. The mechanisms responsible for the improved N retention of traumatized rats consuming the high-protein diets with supplements of arginine and glycine may be related to the role of arginine both as a constituent of muscle tissue and as an intermediate in the urea cycle. 7. In traumatized rats fed the C or EC diets, liver transaminase activity increased whereas the transaminase activity in skeletal muscle decreased. These results support the recent concept that the increased excretion of N following injury arises from diminished reutilization of amino acids by muscle tissue without an acute increase in the rate of muscle catabolism.

Alanine Transaminase↗
PubMed1977

Nitrogen retention in rats fed on diets enriched with arginine and glycine. 2. Effect of diethyl ether anaesthesia on N retention.

1. Adult rats were subjected to a brief period of diethyl ether anaesthesia and were given diets with 200 or 100 g casein/kg with or without arginine plus glycine supplementation in the post-anaesthesia period. Nitrogen retention was measured as well as liver protein content and liver and muscle transaminase activities (L-aspartate aminotransferase (GOT), (EC 2.6.1.1), and L-alanine aminotransferase (GPT)(EC 2.6.1.2). 2. Results demonstrated that anaesthesia-stressed rats consuming the high-protein diet with supplemental arginine and glycine retained twice as much N as did rats given the diet with 200 g casein/kg alone, for the first 5 d post-anaesthesia. 3. Anaesthesia-stressed animals consuming the diets with 100 g casein/kg with or without arginine plus glycine supplementation did not differ from each other in N retention. 4. Liver protein content increased after anaesthesia in rats given the high-protein diets; liver transaminase activity increased, whereas muscle transaminase activity decreased, in animals consuming the high protein diets. 5. Possible mechanisms to account for these results are discussed.

Alanine Transaminase↗
PubMed1977

Amino acid maintenance requirements of young women and of adult rats fed different dietary amino acid patterns.

Adult rats were fed isonitrogenous diets (5% protein equivalent) providing indispensable amino acids either in the whole-egg protein pattern or in the adult rat maintenance pattern of Smith and Johnson (S & J. Brit. J. Nutr. 21:17, 1967). In two separate experiments the threonine and the methionine (total sulfur amino acid) requirements were assessed. Similar responses were obtained with rats on the threonine experiment independent of the pattern of indispensable amino acids fed. In the methionine experiment the rats fed the S & J pattern showed a lower need for this amino acid than the rats fed the egg pattern. When the latter group was switched to the S & J pattern, they too required less methionine. In the experiment with college students (female) fed 7 g of nitrogen/subject per day, the lysine requirement on the whole-egg pattern was compared to the requirement on a pattern equal to twice the previously published requirements for young women. No evidence was obtained over the relatively short experimental period that the lysine requirement differed substantially with change in the pattern of indispensable amino acids.

Adult↗
PubMed1976

Further studies on the arginine requirement of the rabbit.

The arginine requirement of young, female rabbits was reassessed using body weight gain, serum arginine concentration and expired 14CO2 following administration of 14C arginine as criteria of adequacy. With a diet that provided the indispensable amino acids at the previously estimated requirement level the arginine requirement was estimated at or near 0.6% of diet by all three of the criteria studied. When an amino acid pattern based on isolated soy protein was fed, a significantly lower serum arginine level was observed with 0.6% dietary arginine corroborating that the arginine requirement may be higher when this pattern is fed than when the requirement pattern is fed. Liver arginase and kidney transamidinase levels were normal and were not influenced by dietary arginine levels over the range used. Serum creatine phosphokinase, which has been studied in other species in relation to muscular dystrophy, showed a significant increase with increasing dietary level of arginine. No signs of this disorder however, were observed. Adult male rabbits maintained body weight and showed no change in serum arginine concentration when both arginine and glycine were completely omitted from the diet.

Amidinotransferases↗
PubMed1976

Protein and amino acid requirements of the laboratory rabbit.

The arginine requirement of the growing rabbit has been re-investigated and found to vary depending upon the pattern of the indispensable amino acids other than arginine. The requirement was higher on a pattern simulating isolated soy protein than on a pattern that contributed essentially the requirement pattern. The rabbit has been found sensitive to protein quality in the same way as other monogastric animals, including the rat and the chick. Interestingly, soy protein appears to provide a superior amino acid pattern to whole egg. Also, casein may be limiting in arginine for the growing rabbit.

Amino Acids↗
PubMed1975

Comparison of two amino acid solutions for total parenteral nutrition of normal and traumatized hats.

Two amino acid solutions were compared at different levels of nitrogen (N) intake for their effectiveness in promoting N retention in normal and in traumatized rats when given as part of a complete diet under total intravenous feeding conditions. An essential amino acid pattern based on that found in whole egg and one with an essential amino acid pattern based on an egg-potatoe mixture, were equally efficacious in promoting N retention in normal, 300-g rats infused with 75 mg of N and 80 kcal/day. Traumatized rats were in positive N balance on infusions of 400 mg of N/day from either the egg or the egg-protein amino acid solution for the first 5 days postinjury. On day 5 the injured animals showed no significant changes in plasma total protein, albumin, glucose, urea N, total bilirubin, and L-aspartate aminotransferase when compared with each other or with orally fed control rats. The two amino acid solutions were satisfactory sources of amino acids when infused as part of a complete intravenous diet for the purpose of studies in the parenterally fed rat. The results of these studies supported the adequacy of the amino acid requirement data for the adult rat of Nasset (J. Nutr. 61, 555-569, 1957) and of Smith and Johnson (Brit. J. Nutr. 21, 17-27, 1967) but suggested that the NRC values calculated from the data of Benditt et all. (J. Nutr. 40, 335-350, 1950) were too high for several amino acids. An improvement in the surgical cannulation technique is also discussed.

Amino Acids↗
PubMed1975

Levels of histidine and histidine derivatives in breast muscle of protein-depleted and repleted adult cockerels.

Four groups of adult cockerels, consisting of a control group given adequate protein, a protein-depleted group, and two groups that had been given, respectively, a low and a higher nitrogen-containing diet following protein depletion, were killed after appropriate time intervals and histidine and histidine derivatives analyzed in breast muscle extract. The concentration of l-methylhistidine increased more than 12-fold during protein depletion and returned to near control levels during repletion. Carnosine decreased during depletion to less than 1/20 of the concentration in controls, yet increased more rapidly during repletion in the group fed a low-nitrogen diet free of histidine compared to the group fed a high-nitrogen diet containing histidine. Depleted cocks showed an elevation in the concentration of free histidine which decreased toward control levels after repletion. Levels of 3-methylhistidine were highest in the cocks fed diets containing histidine. Evidence for an accumulation in the breast muscle of adult cocks of 3-methylhistidine consisted of unusually high ratios of this derivative to muscle protein in all experimental groups. It was suggested that both 3-methylhistidine and 1-methylhistidine might serve as useful indices for assessing protein depletion in the adult cockerel, but that consideration should be given to the possibility of species differences in the metabolism of histidine derivatives during protein depletion.

Animals↗