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

Experimental diabetes in the rat was induced by alloxan (40 mg/kg body weight) and resulted in permanent hyperglycaemia (mean glycaemia: 403.0 mg/100 ml). The animals were left untreated for more than 16 months. The mesangial cell of the renal glomerulus was studied by serial biopsies performed each month under light anaesthesia in the diabetic animals and in normal controls of the same age. Large dense bodies appeared in the cytoplasm after 3 months in the diabetics and after 10 months in the controls. With time, a larger number of mesangial cells contained these dense bodies. At the end stage they seem to be mainly lipidic. When NO3Ag is given in the drinking water the dense bodies accumulate particles of silver, suggesting that they contain fragments of the basement membrane. While the acid phosphatase reaction was negative in biopsy specimens from diabetic animals, it remains possible that the large dense bodies belong to the lysosomial system. This point, as well as the pathologic significance of the dense bodies is currently investigated.
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PMID:Long-term alloxan diabetes in the rat. Study of mesangial cell morphology by serial biopsies. 19 6

Experiments with rats were set up to study the interaction of hormones with Na+, K+-ATP-ase and Ca2+-ATP-ase of the sarcoplasmatic reticulum fragments and with pyruvate-dehydrogenase of the myocardial mitochondria in healthy rats and the ones with alloxan diabetes. Insulin was found to activate, while epinephrine and c-AMP to inhibit Na+, K+-ATP-ase. The Ca2+-ATP-ase is activated with epinephrine and c-AMP. In alloxan diabetes Na+, K+-ATP-ase is inhibited and Ca2+-ATP-ase and pyruvate-dehydrogenase--activated.
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PMID:[Effect of insulin, adrenaline and cyclic adenosine monophosphate on the activity of transport adenosine triphosphatases and pyruvate dehydrogenase of the rat myocardium under normal conditions and in insular insufficiency]. 19 87

1. The proportion of active (dephosphorylated) pyruvate dehydrogenase in rat heart mitochondria was correlated with total concentration ratios of ATP/ADP, NADH/NAD+ and acetyl-CoA/CoA. These metabolites were measured with ATP-dependent and NADH-dependent luciferases. 2. Increase in the concentration ratio of NADH/NAD+ at constant [ATP]/[ADP] and [acetyl-CoA]/[CoA] was associated with increased phosphorylation and inactivation of pyruvate dehydrogenase. This was based on comparison between mitochondria incubated with 0.4mM- or 1mM-succinate and mitochondria incubated with 0.4mM-succinate+/-rotenone. 3. Increase in the concentration ratio acetyl-CoA/CoA at constant [ATP]/[ADP] and [NADH][NAD+] was associated with increased phosphorylation and inactivation of pyruvate dehydrogenase. This was based on comparison between incubations in 50 micrometer-palmitotoyl-L-carnitine and in 250 micrometer-2-oxoglutarate +50 micrometer-L-malate. 4. These findings are consistent with activation of the pyruvate dehydrogenase kinase reaction by high ratios of [NADH]/[NAD+] and of [acetyl-CoA]/[CoA]. 5. Comparison between mitochondria from hearts of diabetic and non-diabetic rats shows that phosphorylation and inactivation of pyruvate dehydrogenase is enhanced in alloxan-diabetes by some factor other than concentration ratios of ATP/ADP, NADH/NAD+ or acetyl-CoA/CoA.
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PMID:Diabetes and the control of pyruvate dehydrogenase in rat heart mitochondria by concentration ratios of adenosine triphosphate/adenosine diphosphate, of reduced/oxidized nicotinamide-adenine dinucleotide and of acetyl-coenzyme A/coenzyme A. 19 89

In female rats aspirin-induced gastrin mucosal damage was increased and glycoprotein synthesis decreased by fasting and by insulin administration. Glucose added to the drinking water during the fasting period reduced mucosal damage and increased glycoprotein synthesis to control levels. Alloxan diabetes did not affect mucosal damage or glycoprotein synthesis. Alloxan diabetes plus insulin restored blood glucose levels to normal, and susceptibility to aspirin damage and glycoprotein synthesis were also normal. Alloxan diabetes plus fasting restored blood glucose levels to normal but increased aspirin-induced mucosal damage and reduced glycoprotein synthesis. In vitro incubation of gastric mucosal homogenates showed that diburyryl cyclic AMP and theophylline inhibited glycoprotein synthesis but dibutyryl cyclic GMP had no significant effects. The importance of an adequate supply of glucose to the gastric mucosa and the effects of cyclic nucleotides on glycoprotein synthesis are discussed.
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PMID:Effects of blood glucose levels on aspirin-induced gastric mucosal damage. 20 Jan 38

Skeletal muscle cyclic AMP (cAMP) content and glycogen synthesis were investigated in male rats subjected to exhaustive exercise, alloxan diabetes, and combinations of these conditions. After an exhaustive swim or control treatment of wading, randomly selected animals were administered 500 mg glucose via stomach tube. Two hours after glucose administration, gastrocnemius glycogen levels rose from 1.31 to 10.67 mg/g wet wt in fatigued nondiabetics (FND), producing a 94% supercompensation above control values. Glycogen of fatigued diabetics (FD) increased from 0.88 to 4.21 mg/g wet wt during the first 2 hr after glucose administration and did not reach control values for 24 h. In conjunction with these glycogen changes, cAMP increased from 1.23 to 2.59 and 1.47 to 2.81 pmol/mg wet wt for FND and FD, respectively (P less than 0.05). No difference in cAMP levels between diabetics and nondiabetics was found. These in vivo data suggest that insulin may not be essential for muscle glycogen synthesis, but that after glycogen depletion it plays a prominent role in supercompensation. Also, this hormone's mechanism of action in skeletal muscle does not appear to be mediated through alteration in the tissue cAMP concentration.
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PMID:Role of insulin during exercise-induced glycogenesis in muscle: effect on cyclic AMP. 20 69

Ketotic, insulin-requiring diabetes mellitus and a severe peripheral neuropathy developed in a previously healthy 25-year-old man several days after he attempted suicide with rat poison containing N-3-pyridylmethyl N'-p-nitrophenyl urea. Study of islet-cell function ten months after ingestion showed a reduced disappearance rate of intravenous glucose and depressed C-peptide response to intravenous glucose when compared with a normal control but no impairment of glucagon release after intravenous arginine stimulation. Nerve conduction studies demonstrated severe sensory and mild motor neuropathy. Quadriceps capillary basement membrane thickness was in the diabetic range. Because at least 15 similar occurrences have been reported to the manufacturer, this agent appears to be diabetogenic in man, probably causing beta-cell destruction. Niacinamide, which can prevent glucose intolerance in both streptozocin- and alloxan-treated animals and prevents death in rats given this rodenticide, may be a useful antidote.
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PMID:Diabetes mellitus following rodenticide ingestion in man. 20 29

A microelectrode intracellular leading off of the postsynaptic potentials of isolated skeletal muscles was carried out in rats with alloxan diabetes of short duration (1--5 weeks), but manifest (blood sugar level from 150 to 350 mg%). A significant disturbance of the neuro-muscular synaptic transmission in this case was wholly caused by the reduction of the excitatory capacity of the presynaptic terminals. There was seen a reduction of the frequency of the miniature potentials of end plates (PEP), and a reduction of quant PEP composition. A distinct reduction of the intensity of the mediator synthesis, without any significant suppression of the fractional acetylcholine secretion was revealed in determination of the dynamic characteristics of the mediator transformations. This served as the cause of a deficiency of the fraction of a mediator ready for use in the animals suffering from diabetes.
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PMID:[Mechanisms of neuromuscular transmission disorder in rats with alloxan diabetes]. 20 63

Venous blood returning from the splanchnic viscera has liver-supporting (hepatotrophic) qualities not found to the same degree in other kinds of arterial or venous blood. The effects of portal blood have been noted in animals with two livers (or a differential portal blood supply to different regions of one liver) to include hypertrophy, glycogen storage, hyperplasia, capacity for regeneration, increase of several synthetic functions, and maintenance of normal structure. The main splanchnic venous hepatotrophic factors are endogenous hormones of which the single most important is insulin. Thus, the foregoing portal hepatotrophic effects are largely eliminated with the diabetes produced by alloxan or total pancreatectomy. The injury of portacaval shunt is caused by the diversion of the hormones around the liver. Accordingly, the atrophy, injury to the organelles, and loss of the capacity for cell renewal is minimized if insulin is infused into the portally deprived liver. In these and other experiments, exogenous glucagon alone or the addition of glucagon to insulin has had no effect, but this may be because of the masking presence of gut glucagon and other hormonal or non-hormonal substances in our models. At present, the effects on the liver of exogenous insulin, glucagon, epidermal growth factor, and numerous other hormones are being determined by their intraportal infusion into eviscerated dogs in which other endogenous splanchnic factors have been eliminated.
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PMID:A hundred years of the hepatotrophic controversy. 20 94

Gingiva from alloxan and streptozotocin-diabetic rats exhibited markedly enhanced collagenolytic activity in tissue culture. This effect was eliminated by puromycin or by repeated freeze-thawing of the tissue prior to incubation. Soluble extracts of the diabetic gingiva in situ were found to contain breakdown products of collagen similar in size to the reaction products generated by tissue collagenase. These fragments were not detected in the control tissue. This study indicates that experimental diabetes stimulates the synthesis of gingival collagenase in culture and that a similar effect occurs in vivo.
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PMID:Enhanced collagenase activity in diabetic rat gingiva: in vitro and in vivo evidence. 21 Feb

In the paper the author is concerned with the histochemical estimation of the metabolic adaptation of the heart muscle of albino rats during an early experimental alloxan diabetes. It has been found that the state of experimentally produced insulin deficiency directly influences metabolism of the heart muscle and the changes observed in the histochemical reactions prove this. An increase in the intensity of histochemical reactions concerns the PAS-positive reaction and the reactions to the NADH and NADPH tetrazole reductase activities. Alkaline phosphatase shows a decrease in the enzymatic activity, whose nature is transitional and reversible with regard to cytochrome oxidase and ATP-ase. The histochemical picture of metabolic changes depends on the duration time of experimental diabetes.
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PMID:Some histochemical observations on the myocardial metabolism in experimental conditions. Part I. 21 83


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