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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The intensity of reticuloendothelial blockade by carrageenan, silica and ethyl stearate was measured and its effect studied on the susceptibility to tolerance induction by polysaccharide antigens in mice. The most intense RE depression reduced the tolerance threshold dose of levan only by 3-fold and that of dextran B512 not at all. The genetic resistance of BALB/c mice to tolerization with the alpha1-3 glucose epitope of dextran B1355 was not overcome by carrageenan blockade which did however, render them normally susceptible to tolerance induction by human gamma-globulin. PFC responses to immunization by the polysaccharides were diminished by blockade, relative to its intensity and to the antigen itself. These and other data suggest that severe RE blockade (a) can promote tolerance by suppressing the active role(s) of the macrophages in immune induction rather than by sustaining circulating antigen, and (b) depresses responses to thymus-independent antigens, probably by an immunosuppressive influence mediated by damaged macrophages.
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PMID:Influence of reticuloendothelial blockade on the induction of tolerance and immunity by polysaccharides. 5 95

Overnight metabolic studies in 39 poorly controlled insulin-treated diabetic patients aged 9 to 66 years showed hypoglycaemia (blood-glucose less than 2 mmol/1) in 22 patients; it lasted 3 h or more in 17. Hypoglycaemic symptoms were very mild or absent, but 19 patients had other features of overtreatment with insulin. These included lethargy, depression, night sweats, morning headaches, fits (3 patients), glycogen-laden hepatomegaly (3), and acquired tolerance to high doses of insulin (mean 1 u/kg/24 h). The best clinical clue to recurrent nocturnal hypoglycaemia was the intermittent occurrence of symptoms, however "mild" and infrequent these appeared to be. Reduction of insulin by a mean of 25% in these patients (without change of species) did not result in loss of overall control; 1 patient with recurrent ketoacidosis was stablished on 40% of his initial dose. It is difficult, sometimes impossible, to achieve good overnight control with conventional once or twice daily insulin therapy. Since patients readily become tolerant of low blood-glucose levels, reliance on urine tests and symptoms of hypoglycaemia as a guide to dosage easily produces a spiral of overtreatment.
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PMID:Unrecognised nocturnal hypoglycaemia in insulin-treated diabetics. 8 75

Effects of intravenous endotoxin and glucose administration on circulating leukocyte populations were compared in seven normal subjects and seven patients with juvenile-onset diabetes by means of automated cytochemical differential counting to quantitate each cell type. Both groups had comparable control cell counts that were unaffected by glucose tolerance testing but altered significantly by endotoxin. Different patterns of response to endotoxin were observed for different circulating cell types. The response of diabetics was parallel to that of normals but showed lower neutrophil and monocyte rebound, longer lasting depression of lymphocytes and eosinophils, and greater rebound of basophils on the day following endotoxin exposure. Characterization of distinctive normal response patterns of circulating leukocyte populations to endotoxin and comparison with responses in diabetes revealed abnormalities under conditions of stress that may impair the diabetic's ability to cope with acute infection.
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PMID:Effects of acute endotoxemia and glucose administration on circulating leukocyte populations in normal and diabetic subjects. 9 90

Pancreatic islets were microdissected from ob/ob mice, loaded for 2 h with 45Ca and perfused with calcium-deficient medium. Irrespective of the glucose and calcium concentrations in the loading medium, increased glucose in the perfusion medium resulted in reduced amounts of radioactivity in the perfusate. A glucose inhibition of 45Ca washout was also evident when the specific radioactivity of the islets approached that of the labeling medium, indicating that the effect was not simply due to isotopic dilution. The depression of 45Ca washout diminished after culture of the islets in a serum-free medium and it was absent in islets taken from mice homozygous for the gene diabetes. The glucose effect became less pronounced when 50 micron D-600, an inhibitor of the calcium inward transport, was added to the calcium-deficient perfusion medium and abolished in the presence of 20 mM Ca-EGTA. The inhibition of the 45Ca washout observed is not necessarily due to a direct glucose interaction with the outward calcium transport but may also result from stimulation of the uptake and intracellular trapping of the cation.
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PMID:Glucose inhibition of 45Ca efflux from pancreatic islets. 9 51

By determining glycogen synthetase activity, rate of 14C-glucose incorporation and glycogen levels, using pharmacologic agents which act on the alpha, beta M and N receptors, the influence of the autonomic system on synthesis of this polysaccharide in heart and skeletal muscle was analysed. The results indicate that the autonomic system is involved in intracellular autoregulation of glycogen synthetase activity through tissue receptors. Drugs which stimulate the cholinergic system depress this enzyme activity in the heart and skeletal muscle indirectly by releasing endogeneous catecholamines (nicotine-gangliconic effect) and also inhibit utilization of energetic ATP and phosphocreatinine reserves in the heart (muscarinic effect). Stimulation of the alpha-adrenergic receptor enhances glycogen anabolism in both types of muscles depending on the stimulatory influence of nonsterified sugers released in the process of glycogen hydrolysis and depression of cAMP level and presence of glucosteroids. Stimulation of beta-adrenergic receptors induces opposite changes. Analysis of the influence of pharmacologic agents that stimulate and inhibit decomposition and synthesis of glycogen showed that hydrolytic decomposition is probably one of the main processes of intracellular autoregulation of glycogen synthetase activity.
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PMID:The role of receptors of the autonomic system in regulation of glycogen synthetase activity in the heart and skeletal muscle in rats. 11 45

To examine the role of changes in calcium transport by subcellular particles in the pathogenesis of contractile failure due to oxygen lack, both mitochondrial and microsomal fractions were obtained from the isolated hypoxic rat hearts and their calcium binding and uptake abilities were determined by the Millipore filtration technique. The contractile force decreased by about 40, 60 and 70% of the control within 5, 10 and 30 min respectively, of perfusing the heart with hypoxic medium containing glucose. In hearts perfused for 10 min with hypoxic medium containing glucose, calcium binding and uptake by the microsomal fraction decreased significantly. However, mitochondrial calcium binding, but not uptake, decreased significantly on perfusing the hearts with hypoxic medium containing glucose for 20 to 30 min when the microsomal calcium transport was markedly depressed. Reduction in contractile force, calcium binding and uptake by the microsomal fraction as well as calcium binding by mitochondria of hearts made hypoxic for 30 min recovered towards normal upon reperfusion with control medium for 15 min. On the other hand, omitting glucose from the hypoxic medium significantly decreased calcium binding by mitochondrial and microsomal fractions within 10 min of perfusion in comparison to the control and accelerated the effects of hypoxia upon contractile force and microsomal calcium uptake. In contrast to the hypoxic hearts, the mitochondrial calcium uptake decreased significantly and the magnitude of depression in the microsomal calcium binding was appreciably greater in hearts made to fail to a comparable degree upon perfusion with substrate-free medium. The observed defects in calcium transporting properties of microsomal and mitochondrial membranes appear secondary to the contactile failure in hypoxic hearts.
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PMID:Excitation-contraction coupling in heart. XIX. Effect of hypoxia on calcium transport by subcellular particles in the isolated perfused rat heart. 13 Sep 66

A number of studies by the author and other investigators are reviewed in which the in vitro kidney slice technique has been used to evaluate the nephrotoxicity of various compounds. The kidney slice technique can be used to determine the effect of prior drug treatment of laboratory animals on renal organic acid (p-aminohippurate) or organic base (N-methylnicotinamide) transport, on glucose synthesis, and on oxygen consumption by renal coritical slices. The nephrotoxic agents uranyl nitrate and potassium dichromate exert inhibitory effects on renal function, althouhg both agents enhance organic base transport at low doses and potassium dichromate enhances organic acid transport at moderate doses. Enhanced PAH transport has been found to be a sensitive indicator of gentamicin induced nephrotoxicity, while inhibition of other parameters has been reported. The tissue slice method is less effective in evaluation chronic nephrotoxicity such as that produced by lead. The inhibitory effect of mercurial diuretics has been shown to be due to the general depression of metabolic activity by mercury. The kidney slice technique has been found to be a sensitive indicator in the assessment of halogenated hydrocarbon-induced nephrotoxicity. Differential effects of compounds on in vitro organic acid and base trasport provides information about the transport of these compounds as well as about their nephrotoxicity. Although it is often desirable to perform in vivo tests or other in vitro renal function tests, the kidney slice technique has proved to be extremely useful in toxicological evaluations.
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PMID:Differential effects of nephrotoxic agents on renal transport and metabolism by use of in vitro techniques. 13 16

Cardiovascular and metabolic responses to exercise and consecutive epinephrine infusions 24 hours apart were measured in 7 normal individuals before and following a week's administration of ephedrine sulfate. There was evidence of less beta adrenergic response to the second control epinephrine infusion compared to the first control infusion, and the depression of the rise in blood lactate was significantly different. A week of ephedrine produced more profound depression of the beta adrenergic responses to epinephrine with significant differences in the rise in blood glucose and lactate, and the pulse and blood pressure responses. Furthermore, these same responses remained significantly altered when a second epinephrine infusion was performed 36 hours following the last dose of ephedrine. The alterations in the response to epinephrine induced by ephedrine are consistent with the concept of effector cell "subsensitivity," an adaptive response to prolonged excessive stimulation.
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PMID:Subsensitivity to epinephrine following the administration of epinephrine and ephedrine to normal individuals. 16 90

The significance of Ca++ for glucose stimulation of insulin release was studied in an in vitro system with beta-cell-rich pancreatic islets microdissected from oh/ob-mice. There was only a slight depression of cAMP in islets exposed to the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine after withdrawal of Ca++ from the incubation medium. The lack of a stimulatory effect of glucose noted in the absence of extracellular Ca++ is therefore probably accounted for by factors other than impaired adenylate cyclase activity. A rise of extracellular Ca++ above the concentration necessary for obtaining the optimal secretagogic effect of glucose resulted in inhibition of the glucose-stimulated insulin release, leaving basal secretions and islet contents of cAMP unaffected. Evidence was provided in support of the idea that H+ completes for Ca++ in glucose stimulation of insulin release. Both the rate of basal insulin release and that seen after stimulation with glucose were diminished by about 50% after introducing 0.2 mM La+++ in the incubation medium. These observations emphasize the significant role of Ca++ in the regulation of insulin secretion, suggesting that not only a decrease but also an increase of the functionally important intracellular pool(s) of Ca++ can result in a diminished response to glucose.
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PMID:The significance of calcium for glucose stimulation of insulin release. 16 23

The effects on intestinal transport of either a semipurified preparation of enterotoxin elaborated by Klebsiella pneumoniae or similaryly prepared control material were tested by marker perfusion studies in the small intestine of rats. At a concentration of 2 mg/ml, the enterotoxin produced net secretion of water, Na, and Cl in both jejunal and ileal segments; HCO3 transport was not affected. Net secretion was evident within 30 min after intorduction of the toxin and was maximal after 90 min. The addition of 56 mM glucose to the enterotoxin-containing perfusion fluid resulted in reversal of water and Na transport to net absorption in both intestinal segments. The enterotoxin also produced a significant depression of xylose absorption in both the jejunum and ileum but did not affect the absorption of either glucose or L-leucine. Intestinal structure was not altered after perfusion of the toxin but insillation of approximately one-quarter of the total perfusion dose into a ligated jejunal loop for 18 h produced fluid secretion and structural abnormalities. These observations confirm the fact that other species of coliform bacteria in addition to tescherichia coli are capable of elaborating an enterotoxin. Such species commonly contaminate the small intestine of persons with tropical sprue and it is suggested that chronic exposure of the intestinal mucosa to the enterotoxin elaborated by these bacteria may be a factor in the pathogenesis of intestinal abnormalities in thid disorder.
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PMID:Effect of Klebsiella pneumoniae enterotoxin on intestinal transport in the rat. 16 97


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