Separation of two monoamine oxidases from bovine bran.
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Alkaloids↗
Biomedical subjects
R McCauley
Publications and source records attributed to R McCauley.
Early effects of phenobarbital on the adenine nucleotide pool of rat liver.
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Adenine Nucleotides↗
Early effects of phenobarbital on cytoplasmic RNA in rat liver.
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Animals↗
Simulation of organismic morphology and behavior by synthetic poly-alpha-amino acids.
Experiments imitating spontaneous geothermal occurrences have yielded most of the amino acids found in protein. All of the amino acids found in protein are simultaneously condensed, by heating in a range of appropriate conditions, to polymers which have many of the properties of proteins. These properties include molecular weights of many thousand, digestibility by proteolytic enzymes, and catalytic activities. One of the other properties is the tendency to form structured units; these units have many of the attributes of biocells. The processes indicated, and others, comprise a conceptual continuum which, according to accumulated information, must have occurred under the conditions existing in regions of the primitive Earth.
Amino Acids↗
The role of glutaminase in the small intestine.
Glutaminase is the enzyme which hydrolyses glutamine, the main respiratory fuel of the intestine, to yield glutamate and ammonia. Glutaminase has a central role in intestinal metabolism: the products of the reaction catalyzed by glutaminase can be transaminated, catabolized to yield energy or used for the biosynthesis of pyrimidine nucleotides. Experimental treatments which deprive the intestine of glutamine induce intestinal atrophy. In this review, attention is paid to the role of glutaminase in intestinal metabolism. Background information on the structure, kinetics and distribution of glutaminase precede a discussion of the metabolism of glutamine within the intestine. In closing, we review the factors known to regulate glutaminase activity and emphasise that the regulation of glutaminase within the intestine is poorly understood.
Caco-2 Cells↗
American Burn Association/Shriners Hospitals for Children burn outcomes questionnaire: construction and psychometric properties.
To develop a standardized, practical, self-administered questionnaire to monitor pediatric patients with burns and to evaluate the effectiveness of comprehensive pediatric burn management treatments, a group of experts generated a set of items to measure relevant burn outcomes. Children between the ages of 5 and 18 years were assessed in a cross-sectional study. Both parent and adolescent responses were obtained from children 11 to 18 years old. The internal reliability of final scales ranged from 0.82 to 0.93 among parents and from 0.75 to 0.92 among adolescents. Mean differences between parent and adolescent were small; the greatest difference occurred in the appearance subscale. Parental scales showed evidence of validity and potential for sensitivity to change. In an effort to support the construct validity of the new scales, they were compared with the Child Health Questionnaire and related to each other in clinically sensible ways. These burn outcomes scales reliably and validly assess function in patients with burns, and the scales have been developed in such a way that they are likely to be sensitive to change over time.
Activities of Daily Living↗
Influence of glutamine and branched chain amino acids on the jejunal atrophy associated with parenteral nutrition.
Infusions of conventional parenteral nutrients (CPN) are associated with gut atrophy. This may be due to the absence of glutamine in such solutions. Although glutamine is a preferred gut nutrient, it is excluded from CPN because it is unstable at room temperature. This problem may be circumvented either directly by the infusion of fresh solutions of glutamine, or indirectly by the infusion of branched chain amino acids (BCAA). We evaluated the effect of infusing either glutamine, BCAA, or glutamine plus BCAA-enriched CPN on the rat jejunum. Sixty male Wistar rats were randomized to receive 6 days of either conventional parenteral nutrition (CPN), CPN plus 1.5% glutamine (GLN), CPN plus 2% BCAA (BCAA), CPN plus 0.8% BCAA and 1.0% glutamine (GLN/BCAA), or a normal oral diet (Chow). Standardized segments of jejunum were then removed for assessment. Compared with the CPN group, both the GLN/BCAA and the BCAA groups had greater mucosal weights (P less than 0.05) and mucosal protein concentrations (P less than 0.05), the GLN/BCAA group had greater jejunal weights (P less than 0.05), and the GLN group had an increased jejunal weight (P less than 0.05) and a higher crypt cell production rate (P less than 0.05). We conclude that the infusion of glutamine or BCAA-enriched parenteral nutrition improves jejunal morphology compared with conventional parenteral nutrition.
Amino Acids, Branched-Chain↗
Effects of glutamine infusion on colonic anastomotic strength in the rat.
Glutamine is one of the primary respiratory fuels of the colon. However, it is not included in commercial preparations of parenteral nutrients because of its short shelf life. It has been suggested that colonic atrophy induced by conventional parenteral nutrition can be reversed by the intravenous infusion of fresh solutions of glutamine. This study evaluated the hypothesis that glutamine-enriched parenteral nutrition would enhance the strength of a standard colonic anastomosis in undernourished rats. After surgery, the rats were randomized to receive 6 days of postoperative support with either rat chow, conventional parenteral nutrition, or parenteral nutrition containing 1.2% glutamine. Measurement of colonic bursting tension failed to demonstrate any significant differences between the groups under study. In conclusion, the administration of 1.2% glutamine-enriched parenteral nutrition failed to influence the healing of colonic anastomoses in undernourished rats.
Amino Acids↗
The influence of parenteral glutamine and branched-chain amino acids on total parenteral nutrition-induced atrophy of the gut.
We tested the hypothesis that the provision of glutamine and branched-chain amino acids would reverse the gut atrophy that accompanies parenteral nutrition. Three hundred seventy-five rats were randomized into 15 groups to receive either conventional parenteral nutrition, rat food, glutamine-enriched parenteral nutrition (0.5% to 2.5%), branched-chain amino acid-enriched parenteral nutrition (0.8% to 2.0%), or glutamine plus branched-chain amino acid-enriched parenteral nutrition (0.5%/0.4% to 1.25%/1/0%). When compared with effects of conventional parenteral nutrition, the infusion of either glutamine or branched-chain amino acids partially reversed, in a dose-dependent manner, atrophy of the small bowel as assessed by gut weight (p < .05), mucosal weight (p < .05), villous height (p < .05), crypt cell production rate (p < .05), and mucosal protein concentration (p < .05). There was no effect on the large bowel. These results suggest that the parenteral infusion of either glutamine or branched-chain amino acids partially reverses the small-bowel atrophy that is associated with the infusion of solutions of conventional parenteral nutrients.
Amino Acids, Branched-Chain↗
Glutamine and nucleotide metabolism within enterocytes.
Glutamine has an important role as a source of energy for enterocytes. However, it may also have a key role as a source of nitrogen for the synthesis of nucleotides. The relative contribution of de novo synthesis and salvage pathways seems to be affected by the position of enterocytes within the crypt-villus axis as well as the dietary intake of nucleic acids and glutamine. Nucleotides are especially important to enterocytes during intestinal development, maturation, and repair. Hence an understanding of nucleotide metabolism within enterocytes has important implications regarding both the composition and route of administration of nutrient solutions. Many important questions remain unanswered, in particular: Does glutamine stimulate intestinal de novo pyrimidine synthesis via the action of carbamoyl phosphate synthetase I? Can de novo purine synthesis maintain intestinal purine pools in the absence of dietary nucleic acids? And, what are the specific effects of parenterally administered nucleotides on the metabolism and well-being of enterocytes? A greater understanding of these issues will lead to a more rational approach toward the nutritional modulation of gut dysfunction.
Glutamine↗
Differential effects of proteinase K on the components of the liver microsomal cytochrome P-450 mixed function oxidase system.
Mild proteolysis of rat liver microsomes with increasing concentrations of proteinase K caused a marked decrease in the levels of microsomal cytochrome P-450 reductase (Fp) without having any significant effect on the cytochrome P-450s. About 20% of the microsomal cytochrome b5 was susceptible to proteolysis at low concentrations of proteinase K, while the remaining 80% was resistant to proteolysis, even at significantly higher proteinase K concentrations. Low concentrations of the proteases released about 30% of Fp from microsomes isolated from both uninduced and phenobarbital-induced rats, but did not affect the rates of benzphetamine bital-induced rats, but did not affect the rates of benzphetamine demethylation significantly. Further depletion of microsomal Fp at higher concentrations of proteinase K resulted in reductions of the rates of benzphetamine demethylation. However, even at higher protease concentrations, the decrease in the rate of the demethylation reaction was significantly less than the loss of Fp. Similar results were observed for the metabolism of two other substrates, 7-ethoxycoumarin and p-nitroanisole, suggesting that the P-450s, not the Fp, were the rate-limiting components in the metabolism of these xenobiotics by microsomes. It is clear that the decreases in the P-450-dependent oxidations were due to depletion of the NADPH-cytochrome P-450 reductase since reconstituting the protease-treated microsomes with native Fp restored the oxidation reactions. The amount of Fp required to completely restore the oxidation of benzphetamine only partially restored the oxidation of 7-ethoxycoumarin and p-nitroanisole.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗