Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study we examined the structural integrity of the myelin sheath in the peripheral nerves from short-term streptozotocin (STZ)-treated diabetic rats, using ESR spectroscopy as a tool in determining the dynamic state and the structure of the myelin lipid phase. Experiments were performed on spin-labeled sciatic and sural nerves from STZ-treated Hannover-Wistar rats and age-matched controls. The spectrum analysis employed a numerical simulation model with the set of fitting parameters that in the same time relate the ESR line shape and structure and dynamics of the probed environment. The simulation considered three spectral components weighted and summed in the composite spectrum. The comparative analysis of results showed the fraction of the spectral component II to be significantly increased in the spectra of diabetic rats, indicating the significant increase in overall fluidity of the myelin structure. The origin of fluidity changes was further investigated using an experimental model for demyelination (local injection of ethidium bromide in vivo), proteolytic action of trypsin in vitro, and osmotic myelin swelling in vitro. Analysis and comparison of the results suggested a conclusion in terms of changed biophysical properties of the myelin lipid phase in peripheral nerves in the pathology of diabetes.
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PMID:Fluidity of the myelin sheath in the peripheral nerves of diabetic rats. 1156 54

The advanced glycation end-product (AGE) hypothesis proposes that accelerated chemical modification of proteins by glucose during hyperglycemia contributes to the pathogenesis of diabetic complications. The two most commonly measured AGEs, N(epsilon)-(carboxymethyl)lysine and pentosidine, are glycoxidation products, formed from glucose by sequential glycation and autoxidation reactions. Although several compounds have been developed as AGE inhibitors and are being tested in animal models of diabetes and in clinical trials, the mechanism of action of these inhibitors is poorly understood. In general, they are thought to function as nucleophilic traps for reactive carbonyl intermediates in the formation of AGEs; however alternative mechanisms of actions, such as chelation, have not been rigorously examined. To distinguish between the carbonyl trapping and antioxidant activity of AGE inhibitors, we have measured the chelating activity of the inhibitors by determining the concentration required for 50% inhibition of the rate of copper-catalyzed autoxidation of ascorbic acid in phosphate buffer. All AGE inhibitors studied were chelators of copper, as measured by inhibition of metal-catalyzed autoxidation of ascorbate. Apparent binding constants for copper ranged from approximately 2 mm for aminoguanidine and pyridoxamine, to 10-100 microm for carnosine, phenazinediamine, OPB-9195 and tenilsetam. The AGE-breakers, phenacylthiazolium and phenacyldimethylthiazolium bromide, and their hydrolysis products, were among the most potent inhibitors of ascorbate oxidation. We conclude that, at millimolar concentrations of AGE inhibitors used in many in vitro studies, inhibition of AGE formation results primarily from the chelating or antioxidant activity of the AGE inhibitors, rather than their carbonyl trapping activity. Further, at therapeutic concentrations, the chelating activity of AGE inhibitors and AGE-breakers may contribute to their inhibition of AGE formation and protection against development of diabetic complications.
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PMID:Chelating activity of advanced glycation end-product inhibitors. 1167 37

To elucidate the mechanism underlying diabetes caused by mitochondrial gene mutations, we created a model by applying 0.4 microg/ml ethidium bromide (EtBr) to the murine pancreatic beta cell line betaHC9; in this model, transcription of mitochondrial DNA, but not that of nuclear DNA, was suppressed in association with impairment of glucose-stimulated insulin release (Hayakawa, T., Noda, M., Yasuda, K., Yorifuji, H., Taniguchi, S., Miwa, I., Sakura, H., Terauchi, Y., Hayashi, J.-I., Sharp, G. W. G., Kanazawa, Y., Akanuma, Y., Yazaki, Y., and Kadowaki, T. (1998) J. Biol. Chem. 273, 20300-20307). To elucidate fully the metabolism-secretion coupling in these cells, we measured glucose oxidation, utilization, and lactate production. We also evaluated NADH autofluorescence in betaHC9 cells using two-photon excitation laser microscopy. In addition, we recorded the membrane potential and determined the ATP and ADP contents of the cells. The results indicated 22.2 mm glucose oxidation to be severely decreased by EtBr treatment compared with control cells (by 63% on day 4 and by 78% on day 6; both p < 0.01). By contrast, glucose utilization was only marginally decreased. Lactate production under 22.2 mm glucose was increased by 2.9- and 3.5-fold by EtBr treatment on days 4 and 6, respectively (both p < 0.01). Cellular NADH at 2.8 mm glucose was increased by 35 and 43% by EtBr on days 4 and 6 (both p < 0.01). These data suggest that reduced expression of the mitochondrial electron transport system causes NADH accumulation in beta cells, thereby halting the tricarboxylic acid cycle on one hand, and on the other hand facilitating anaerobic glucose metabolism. Glucose-induced insulin secretion was lost rapidly along with the EtBr treatment with concomitant losses of membrane potential depolarization and the [Ca(2+)](i) increase, whereas glibenclamide-induced changes persisted. This is the first report to demonstrate the connection between metabolic alteration of electron transport system and that of tricarboxylic acid cycle and its impact on insulin secretion.
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PMID:Switch to anaerobic glucose metabolism with NADH accumulation in the beta-cell model of mitochondrial diabetes. Characteristics of betaHC9 cells deficient in mitochondrial DNA transcription. 1216 97

Anesthesia during and after off-pump surgery is critical for the outcome of the procedure. Intubation time has been shown to correlate with ICU time and length of stay. This study is to evaluate the extubation time and predictors of prolonged extubation in this institution. One hundred and sixty consecutive patients during Jan 2001-June 2002, excluding pre-operative tracheostomy (n = 1) were retrospectively reviewed. Anesthetic agents include fentanyl, rocuronium Bromide, midazolam and sevoflurane. Phenylephrine and nitroglycerine were used to maintain adequate arterial pressures. Post-operative pain control was mainly with intravenous fentanyl and oral pain medications. The extubation time was divided into 4 groups; 0-2 h, n = 76, mean = 1.11 +/- 0.5 h; 2-4 h, n = 30, mean = 2.91 +/- 0.5 h; 4-24 h, n = 39, mean = 11.44 +/- 7.3 h; > 24 h, n = 5, mean = 33.3 +/- 21 h. The data were collected and analyzed following the guidelines of National STS cardiac surgery database. All pre-operative risk factors included: Age (> 70 yrs vs < or = 70 yrs), gender (male vs female), diabetes (yes vs no), hypertension (yes vs no), morbid obesity (yes vs no), renal insufficiency (yes vs no), chronic obstructive lung disease (yes vs no), history of cerebrovascular accident (yes vs no), smoking (yes vs no), dyslipidemia (yes vs no), history of myocardial infarction (MI) (yes vs no), history of congestive heart failure (CHF) (yes vs no), unstable angina (yes vs no), left ventricular ejection fraction (LVEF) (> 40% vs < or = 40%), left main (LM) lesion (LM > 50% vs LM < or = 50%), intra-aortic balloon pump (IABP) used (yes vs no) and time between operating and closing (> 4.30 h vs < or = 4.30 h) were used to predict failed early extubation (2 h). More than 50 per cent of the patients were extubated in less than 2 h (1.11 +/- 0.5 h) and only 5 patients were extubated after 24 h. Univariate analysis revealed old age, diabetes, MI, CHF, LVEF < or = 0.4 and the use of IABP are the predictors (p < 0.05) of failed early extubation. Multivariate analysis of these variables revealed old age with adjusted odds ratio of 4.6 (95% CI = 1.5-13.7) p < 0.01, diabetes with adjusted odds ratio of 3.2 (95% CI = 1.3-7.5) p < 0.01 and IABP used with adjusted odds ratio of 4.3 (95% CI = 1.3-14.6) p = 0.02 are the predictors of fail early extubation. The findings suggested early extubation is possible in OPCAB surgery and attention should be made when operate in patients who have old age, diabetes, and IABP used.
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PMID:Off-pump coronary artery bypass surgery: evaluation of extubation time and predictors of failed early extubation. 1286 66

The hypothesis that in hypertensive patients with renal parenchymal disease sympathetic activity is "inappropriately" elevated and that this overactivity is a feature of renal disease and not of a reduced number of nephrons per se is addressed. Fifty seven patients with renal disease (various causes, no diabetes, all on antihypertensive medication) were studied, age range 18 to 62, creatinine clearance 10 to 114 ml/min per 1.73 m(2). Antihypertensives were stopped, but diuretics were allowed, to prevent overhydration. Matched control subjects were also studied. The effect of changes in fluid status was examined in seven patients while on and after stopping diuretics and in eight control subjects while on low- and high-sodium diet. Seven kidney donors were studied before and after unilateral nephrectomy. Sympathetic activity was quantified as muscle sympathetic nerve activity (MSNA) in the peroneal nerve. Mean arterial pressure, MSNA, and plasma renin activity were higher in patients than in control subjects, respectively (115 +/- 12 and 88 +/- 11 mmHg, 31 +/- 15 and 18 +/- 10 bursts/min, and 500 [20 to 6940] and 220 [40 to 980] fmol/L per s; P < 0.01 for all items). Extracellular fluid volume (bromide distribution) did not differ. Seven patients were studied again after stopping diuretics. MSNA decreased from 34 +/- 18 to 19 +/- 18 bursts/min (P < 0.01). Eight healthy subjects were studied during low- and high-sodium diet. MSNA was 26 +/- 12 and 13 +/- 7 bursts/min (P < 0.01). The curves relating extracellular fluid volume to MSNA were parallel in the two groups but shifted to a higher level of MSNA in the patients. In the kidney donors, creatinine clearance reduced by 25%, but MSNA was identical before and after donation. It is concluded that in hypertensive patients with renal parenchymal disease, sympathetic activity is inappropriately high for the volume status and that reduction of nephron number in itself does not influence sympathetic activity.
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PMID:Sympathetic nerve activity is inappropriately increased in chronic renal disease. 1463 22

As a result of oxidative and carbonyl stress, advanced glycation end products (AGEs) are involved in the pathogenesis of severe and frequent diseases and their fatal vascular/cardiovascular complications, i.e. diabetes mellitus and its complications (nephropathy, angiopathy, neuropathy and retinopathy, renal failure and uremic and dialysis-associated complications), atherosclerosis and dialysis-related amyloidosis, neurodegenerative diseases, and rheumatoid arthritis. They are formed via non-enzymatic glycation which is specifically enhanced through the presence of oxidative and carbonyl stress, and their ability to form glycoxidation products in peptide and protein structures finally modulating or inducing biological reactivity. Food can be another source of AGEs; however, high serum AGEs in hemodialysis patients might reflect nutritional status better. Several methods of renal replacement therapy have been studied in connection with the AGE removal, but unfortunately the possibilities are still unsatisfactory even if high flux dialysis, hemofiltration, or hemodiafiltration give better results than conventional low flux dialysis. AGEs are currently being studied in the patients on peritoneal dialysis as their precursors can be formed in the dialysis fluid. AGEs can cause damage to the peritoneum and so a loss of ultrafiltration capacity. Many compounds give promising results in AGE inhibition (inhibition of formation of AGEs, inhibition of their action or degradation of AGEs), are tested for these properties, and eventually undergo clinical studies (e.g. aminoguanidine, OPB-9195, pyridoxamine, antioxidants, N-phenacylthiazolium bromide, antihypertensive drugs, angiotensin-converting enzyme inhibitors and angiotensin II receptor-1 antagonists).
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PMID:Advanced glycation end products in clinical nephrology. 1467 11

The subject is a diabetic and hypertensive woman treated early during an unplanned pregnancy with a multi-drug regimen that included three drugs with no prior history for use in pregnant women (rosiglitazone, gliclazide, atorvastatin). She was under care for chronic hypertension, which she suffered for 14 years, and diabetes mellitus, hypercholesterolemia, anxiety disorder, morbid obesity and epilepsia for 5 years. She was exposed to rosiglitazone (4mg/day), gliclazide (60mg/day), and atorvastatin (40mg/day) in addition to acarbose, spironolactone, hydrochlorothiazide, carbamazepine, thioridazine, amitryptiline, chlordiazepoxide, and pipenzolate bromide during the first 7 weeks of gestation while unaware of pregnancy. Pharmacotherapy was adjusted following clinical recognition of pregnancy during the 8th week. She gave birth to a normal healthy infant at the 36th week of gestation. This is the first reported case of human exposure to rosiglitazone, gliclazide, and atorvastatin during pregnancy. Although the normal pregnancy outcome does not address the safety of these drugs for use in pregnancy, these data contribute to a limited knowledge regarding human exposure to these antidiabetic drugs.
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PMID:Normal pregnancy outcome following inadvertent exposure to rosiglitazone, gliclazide, and atorvastatin in a diabetic and hypertensive woman. 1513 57

Chronic arsenic exposure increases risk for the development of diabetes, vascular disease, and cancers of the skin, lung, kidney, and bladder. This study investigates the effects of arsenite [As(III)] on human urothelial cells (UROtsa). As(III) toxicity was determined by exposing confluent UROtsa cells to As(III) (0.5-200 microM). Depleting cellular glutathione levels with buthionine sulfoximine (BSO) potentiated the toxicity of As(III). Cell viability was assessed with the (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. UROtsa cell ability to biotransform As(III) was determined by dosing cells with environmentally relevant concentrations of As(III) followed by HPLC/ICP-MS analysis of cell media and lysate. Both pentavalent and trivalent monomethylated products were detected. Although cytotoxicity was observed at high doses of As(III) (approximately 100 microM) in UROtsa cells, perturbations of a variety of molecular processes occurred at much lower doses. Exposure to low-level As(III) (0.5-25 microM) causes an accumulation of ubiquitin (Ub)-conjugated proteins. This effect is enhanced when cellular glutathione levels have been reduced with BSO treatment. Because As(III) has many effects on UROtsa cells, a greater understanding of how As(III) is affecting cellular proteins in a target tissue will lead to a better understanding of the mechanism of toxicity and pathogenesis for low-level As(III).
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PMID:Effects of arsenite on UROtsa cells: low-level arsenite causes accumulation of ubiquitinated proteins that is enhanced by reduction in cellular glutathione levels. 1527 21

Apoptosis of endothelial cells may be an important risk factor contributing to the incidence of vascular complications in diabetes. In the present study, we tested the effect of 3,4,5,6-tetrahydroxyxanthone, a synthetic xanthone derivative, on apoptosis induced in human umbilical vein endothelial cells (HUVEC) by a high glucose concentration. Cell apoptosis was detected using DNA ladder formation and flow cytometric techniques. The expression of Bcl-2 protein was analysed using flow cytometric techniques. Lactate dehydrogenase (LDH) activity and malonyldialdehyde (MDA) content in the medium were measured. Cell viability was assayed by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method. Exposure of HUVEC to a high glucose concentration (30 mM) for 48 h markedly increased LDH release and MDA content in the medium and induced apoptosis and Bcl-2 protein expression in HUVEC. Pretreatment with 3,4,5,6-tetrahydroxyxanthone (1, 3 or 10 microM) or probucol (10 microM) significantly decreased the level of LDH and MDA in the medium, reduced apoptosis and increased the expression of Bcl-2 protein in HUVEC. These results suggest that 3,4,5,6-tetrahydroxyxanthone inhibits high-glucose-induced endothelial cell apoptosis by increasing Bcl-2 protein expression in HUVEC.
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PMID:3,4,5,6-Tetrahydroxyxanthone prevents vascular endothelial cell apoptosis induced by high glucose. 1533 10

The aim of this work was to investigate the interrelated effects of glucose, nitric oxide (NO) and erythropoietin on neuronal survival in retinal cultures, thereby exploring the mechanism of neuronal death in the diabetic retina. Rat retinal cells were cultured in low (5 mM) or high (15 mM) glucose concentrations. After 9 days, cell viability was assessed by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and NO production was determined by the Griess reaction. Immunohistochemistry was used to quantify GABA-labelled neurones and cells staining for DNA breakdown. High or low glucose concentrations had no effect on basal NO production or the survival of neurones in culture, but treatment with N-nitro-L-arginine methyl ester reduced extracellular levels of NO and increased neuronal survival at both concentrations of glucose. Erythropoietin decreased cell death and NO levels, but only in cultures grown in low concentrations of glucose. It is concluded that erythropoietin's neurotrophic function in the retina is attenuated at glucose concentrations similar to those which occur in diabetes.
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PMID:Neuronal death in primary retinal cultures is related to nitric oxide production, and is inhibited by erythropoietin in a glucose-sensitive manner. 1565 19


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