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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histochemical investigations on elastic membranes of vessels under normally and diabetic conditions have been accomplished. These studies were made on man (diabetic and non-diabetic subjects) and on rats with streptozotocin-diabetes. The results are comparable among one another. The amino acids histidine, tyrosine and tryptophan were not demonstrable. The detection of primary NH2-groups (ninhydrin-Schiff-method and o-diacetylbenzen-reaction) was positive however. The results of the reactions in healthy men and animals were more distinct than in diabetic human subjects and animals. In healthy children the intensities of the histochemically reactions were higher than in adults.
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PMID:[Histotopochemical investigations on elastic membranes of blood vessels with special regard to diabetes mellitus. I. Proteins (author's transl)]. 12 78

The protein anabolic effect of branched chain amino acids was studied in isolated quarter diaphragms of rats. Protein synthesis was estimated by measuring tyrosine incorporation into muscle proteins in vitro. Tyrosine release during incubation with cycloheximide served as an index of protein degradation. In muscles from normal rats the addition of 0.5 mM leucine stimulated protein synthesis 36--38% (P less than 0.01), while equimolar isoleucine or valine, singly or in combination were ineffective. The three branched chain amino acids together stimulated no more than leucine alone. The product of leucine transamination, alpha-keto-isocaproate, did not stmino norborane-2-carboxylic acid (a leucine analogue) were ineffective. Leucine and isoleucine stimulated protein synthesis in muscles from diabetic rats.Leucine, isoleucine, valine and the norbornane amino acid but not alpha-ketoisocaproate or beta-hydroxybutyrate decreased the concentration of free tyrosine in tissues during incubation with cycloheximide; tyrosine release into the medium did not decrease significantly. Leucine caused a small decrease in total tyrosine release, (measured as the sum of free tyrosine in tissues and media), suggesting inhibition of protein degradation. The data suggest that leucine may be rate limiting for protein synthesis in muscles. The branched chain amino acids may exert a restraining effect on muscle protein catabolism during prolonged fasting and diabetes.
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PMID:Studies concerning the specificity of the effect of leucine on the turnover of proteins in muscles of control and diabetic rats. 13 65

Experiments on male rats showed that following subcutaneous injection of alloxan in a dose of 15 mg per 100 g of body weight amylolytic, invertase, glycyl-l-tyrosine dipeptidehydrolase activity of the mucosa of the small intestine altered differently. As a result, there occurred a deviation of the enzymatic spectrum from the normal characterized by a sharp increase (with the development of diabetes) of the activity of the carbohydrate hydrolysing enzymes (amylase and invertase) with a simultaneous reduction of the activity of the enzymes participating in protein (dipeptidase) and fat (monglyceridlipase) hydrolysis.
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PMID:[Effect of alloxan diabetes on the enzyme activity of the mucous membrane of the small intestine]. 72 80

The amino acid pattern following total hip replacement is characterized by increases in muscle of the branched chain amino acids (leucine, isoleucine and valine), the aromatics (phenylalanine and tyrosine) as well as methionine. The nonessential amino acids in muscle tend to decline, glutamine having the most marked change. Plasma levels of the essential amino acids increase while the nonessentials tend to decrease. This pattern differs from that observed in other catabolic states (uremia, starvation, untreated diabetes) and is significantly different from the effects of inactivity and starvation combined. This suggests that injury can be characterized by a unique pattern of muscle and plasma amino acids.
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PMID:Muscle and plasma amino acids after injury: the role of inactivity. 73 57

The content of the following 10 amino acids was investigated by means of a microbiological method (with the use of auxotrophic E. coli mutants) in 23 patients with diabetes mellitus with fatty infiltration of the liver and in 27 patients without it: histidine, proline, methionine, cystine, tryptophane, leucine, arginine, tyrosine, lysine, and phenylalanine. Results of study of the amino acid balance were compared with the morphological changes in the liver (the material was obtained by biopsy). All the diabetic patients displayed an increase in the proline, tryptophane, tyrosine, leucine, and cystine content, and a reduction of phenylalanine and lysine level. Fatty hepatocyte infiltration was also accompanied by a significant elevation of methionine and a reduction of arginine content. A tendency to normalization of leucine and lysine only was seen after the treatment of diabetic patients with fatty hepatocyte infiltration; diabetic patients without any fatty infiltration showed normalization in the tyrosine, lysine content and a tendency to the normalization of the cystine, tryptophane level, but no change in the methionine content.
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PMID:[Characteristics of the amino acid spectrum of blood serum in diabetes mellitus]. 88 34

We describe a method for determining those urinary total phenolic compounds that are tyrosine analogs or metabolites, such as thyroxine and catecholamines. The urine sample, 4-aminoantipyrine in carbonate-bicarbonate buffer, and potassium ferricyanide solution are mixed and the quinoneimine dye that forms is measured at 500 nm. Some cases of hyperthyroidism, diabetes mellitus, nephrosis, obesity, hypertension, or catecholamine-producing tumor showed above-normal values, so that this determination seems useful as a screening test for these disorders.
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PMID:Determination of urinary total phenolic compounds with use of 4-aminoantipyrine: suggested screening test for hyperthyroidism and for catecholamine-producing tumor. 91 84

Renal substrate exchange was examined in five male patients with insulin-dependent diabetes mellitus of several years' duration. Insulin was withheld for twenty-four hours prior to the study. A renal vein was catheterized from the femoral vein, and PHA-clearance was employed for the determination of effective renal blood flow. None of the patients was in ketoacidosis, but all were moderately hyperglycemic in the fasting states (16.8 +/- 1.5 mmol/L.) (225-384 mg./100 ml.). Nevertheless, no net release of glucose from the kidney was detectable. Instead, there was a significant net renal uptake of glucose (320 +/- 80 mumol/min.). In addition, there was a significant net uptake of glycerol and a net release of pyruvate. Renal amino acid exchange was similar to that reported for healthy subjects: glutamine, glycine, proline, and citrulline were taken up and serine, alanine, cystine, tyrosine, and threonine were released by the kidney. It is concluded that (a) in nonketoacidotic diabetics there is no net production of glucose by the kidney; (b) renal amino acid exchange in diabetics is similar to that of healthy individuals; and (c) the kidney is not an important gluconeogenic organ in human diabetes.
Diabetes 1975 Aug
PMID:Renal substrate exchange in human diabetes mellitus. 115 36

Effects of histidine or methionine imbalance and dietary levels (3-50%) of casein on food intake and preference of young, adult, and diabetic (2.5 month old) rats were examined. Depressions in food intake and growth caused by ingestion of the imbalanced diet were greatest in young rats and least or absent in diabetic rats. Alloxan diabetes induced hyperphagia and elevated concentrations of plasma branched-chain amino acids and decreased concentrations of tryptophan and tyrosine. The diabetic rats fed the imbalanced diet for 9 days had a higher concentration of the limiting amino acid in the plasma than the adult normal rats fed the same diet. The diabetic rats preferred the imbalanced diet over a protein-free diet when they were fed these diets concurrently. Ingestion of the imbalanced diet by normal rats caused greater changes in plasma and brain amino acid patterns than did the protein-free diet. Unlike the diabetic rats, the normal rats, especially the young rats, strongly preferred the protein-free diet over the imbalanced diet. The normal rats also preferred a 10% casein diet supplemented with L-methionine over a low or high casein diet. It seemed that young rats were able to select a protein diet that supported maximal growth when proportions of dietary amino acids were balanced. It also seemed that the susceptibility of the rats to amino acid imbalance varied directly with the status of overall protein synthesis of the animals.
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PMID:Effects of amino acid imbalance and protein content of diets on food intake and preference of young, adult, and diabetic rats. 119 6

Incorporation of radiolabeled precursors into muscle proteins was studied in isolated rat hemidiaphragms. A mixture of three branched-chain amino acids (0.3 mM each) added to media containing glucose stimulated the incorporation of [14C]lysine into proteins. When tested separately, valine was ineffective, isoleucine was inhibitory, but 0.5 mM leucine increased the specific activity of muscle proteins during incubation with [14C]lysine or [14C]acetate in hemidiaphragms from fed or fasted rats incubated with or without insulin. Preincubation with 0.5 mM leucine increased the specific activity of muscle proteins during a subsequent 30- or 60-min incubation with [14C]lysine or [14C]pyruvate without leucine. Preincubation with other amino acids (glutamate, histidine, methionine, phenylalanine, or tryptophan) did not exert this effect. When hemidiaphragms were incubated with a mixture of amino acids at concentrations found in rat serum and a [14C]lysine tracer, the specific activity of muscle proteins increased when leucine in the medium was raised from 0.1 to 0.5 mM. Experiments with actinomycin D and cycloheximide suggested that neither RNA synthesis nor protein synthesis are required for the initiation of the leucine effect. Leucine was not effective when added after 1 h preincubation without leucine. The concentration of lysine in the tissue water of diaphragms decreased during incubation with 0.5 mM leucine in the presence or absence of cycloheximide, suggesting that leucine inhibited protein degradation. During incubation with [3h]tyrosine (0.35 mM) the addition of 0.5 mM leucine increased the specific activity of muscle proteins, while the specific activity of intracellular tyrosine remained constant and its concentration decreased, suggesting that leucine also promoted protein synthesis. The concentration of leucine in muscle cells or a compartment thereof may play a role in regulating the turnover of muscle proteins and influence the transition to negative nitrogen balance during fasting, uncontrolled diabetes, and the posttraumatic state. Leucine may play a pivotal role in the protein-sparing effect of amino aicds.
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PMID:Leucine. A possible regulator of protein turnover in muscle. 123 98

Human umbilical vein endothelial cells (HUVEC) cultured in high glucose exhibit delayed replication and colchicine-resistant microtubules. Tubulin dysfunction and stabilization, brought about by acetylation of the NH2-terminal residues, loss of the C-terminal tyrosine and binding of microtubular-associated proteins (MAPs) may be involved in the above phenomenon. The effects of L-tyrosine on HUVEC replication in high glucose were tested and the hypothesis that non-enzymatic glycosylation might impair tubulin depolymerization was also checked by growing the cells in the presence of L-glucose, which binds to intracellular proteins but remains metabolically inactive. After 18 days in culture, the number (mean +/- SEM, n = 7) of HUVEC grown in 28.0 mmol/l D-glucose (435.7 +/- 59.1 x 10(3)) was lower than in 5.6 mmol/l D-glucose (818.3 +/- 75.2 x 10(3)), p < 0.0001. The addition of L-tyrosine 1.7 mmol/l corrected such growth inhibition (623.3 +/- 81.7 x 10(3)), p < 0.0001 vs. D-glucose 28.0 mmol/l, but the cells recovered were less numerous than in physiological glucose alone (p = 0.016). The addition of L-tyrosine to D-glucose 5.6 mmol/l (731.0 +/- 63.2 x 10(3)) did not modify the cell number significantly. HUVEC in extra L-glucose (687.4 +/- 72.0 x 10(3)) were less numerous than in 5.6 mmol/l D-glucose, p = 0.028, but more than in D-glucose 28 mmol/l, p < 0.0001, and were not modified by the addition of L-tyrosine (729.4 +/- 67.1 x 10(3)). HUVEC grown in physiologic and high glucose exhibited specific immunofluorescence for acetylated tubulin and MAPs.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes Res 1992 Feb
PMID:Delayed replication of human umbilical vein endothelial cells in high glucose is corrected by L-tyrosine. 128 44


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