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

The influence of experimentally induced diabetes on rat dermal collagen crosslinking was investigated in male albino rats. In comparison to the normal, the diabetic group demonstrated decrease in percent reversibility of neutral salt-soluble collagen gel and susceptibility of insoluble collagen to denaturing agents and pronase whereas the aldehyde content was significantly increased. The electrophoretic gels revealed a marked decrease of alpha/beta ratio in diabetic animals. The results indicated that both the intra- and intermolecular crosslinkings of collagen were increased in experimentally induced diabetes.
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PMID:Influence of streptozotocin- and alloxan-induced diabetes on the crosslinking of dermal collagen. 621 10

A possible role for growth hormone (GH) in stimulating islet B-cell replication was examined in neonatal rat pancreatic monolayer cultures. Addition of ovine GH (1000 ng/ml) to serum-free medium for 2 days resulted in a significant increase (+114%) in [3H]thymidine labeling of B-cells in aldehyde-thionine-stained autoradiographs, and a similar increase in the B-cell mitotic index. The stimulatory effects of GH on islet B-cell replication were greatest in serum-free medium, unaffected by glucose concentrations (2.8--16.7 mM), and not accompanied by any stimulation of insulin release. The threshold concentration of GH for a significant stimulatory effect on B-cell replication was 30 ng/ml. The insulin-like growth factor, multiplication stimulating activity (MSA), also effectively stimulated B-cell replication. Although some effects of GH are mediated by the insulin-like growth factors (IGFs), the effects of GH on B-cell replication did not appear to be mediated by IGFs since (1) the maximal effect of GH (+156%) was significantly greater than that of MSA (+91%); (2) the combination of maximal stimulatory concentrations of GH and MSA produced an additive effect; and (3) a significant effect of GH on B-cell replication was observed as early (8 h) as that produced by MSA. These results suggest that GH can stimulate islet B-cell replication directly, and that this effect may not depend on production of either insulin-like growth factors.
Diabetes 1983 Apr
PMID:Growth hormone stimulates islet B-cell replication in neonatal rat pancreatic monolayer cultures. 633 3

A specific and accurate method for the quantitation of the azomethine linkage present in non-enzymatically glycosylated haemoglobin is described. This protein is hydrolysed for 5 h in 1 M oxalic acid at 100 degrees C to yield 5-(hydroxymethyl)-2-furfur-aldehyde (5-HMF), known as a specific degradation product of hexoses linked to the protein. 5-HMF is then purified through a Sep-Pak C18 cartridge and measured by its absorption at 280 nm after separation on a C18 reversed-phase silica column. Quantitation is made accurate by using 1-methylxanthine as internal standard throughout the whole procedure. The identity and the purity of the 5-HMF chromatographic peak was ascertained by UV spectroscopy, gas chromatography on a glass capillary column and mass spectrometry. The method has been successfully used for 5-HMF determinations in monitoring diabetes mellitus patients. The mean values, expressed as nmol of 5-HMF per mg of haemoglobin were 0.64 +/- 0.13 (S.D.) for 27 controls and 1.32 +/- 0.39 for 78 diabetic patients. Unlike the usually employed thiobarbituric acid assay, the present procedure is truly specific for the 5-HMF determination.
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PMID:Glycosylated haemoglobin: high-performance liquid chromatographic determination of 5-(hydroxymethyl)-2-furfuraldehyde after haemoglobin hydrolysis. 649 Jul 66

Post-translational modifications of hemoglobin can provide special insights into metabolic disorders. A variety of small molecules in health and disease can form covalent adducts with hemoglobin. The most abundant and best understood of these nonenzymatic modifications is the glycosylation of hemoglobin at the N-terminus of the beta chain (Hb AIc) as well as at the N-terminus of the alpha chain and at certain lysine residues. Glycosylated hemoglobins are elevated in diabetics and offer a useful way of monitoring diabetic control. Moreover, non-enzymatic glycosylation of other tissues may contribute significantly to the long term complications of diabetes. Additional minor hemoglobin components can be formed from other small reactive compounds. For example, cyanate, a breakdown product of urea, reacts with hemoglobin to form distinct minor components in red cells of uremic patients. Acetaldehyde can form hemoglobin adducts in red cells of alcoholics. Thus, hemoglobin can be viewed as a "reporter molecule", revealing metabolic perturbations in a variety of diseases.
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PMID:Post-translational modifications of hemoglobin. 653 26

Experiments on white male rats were performed to study lipid peroxidation in the rat liver at varying times of the development of alloxan diabetes. After administering alloxan in a dose of 16 mg/100 g bw both non-enzymatic and enzymatic lipid peroxidation in the liver was substantially activated, while the blood glucose level ascended. Injection of insulin to rats with alloxan diabetes entailed a reduction of the blood glucose content and the formation of the final product of lipid peroxidation, malonic aldehyde (during non-enzymatic process). Pretreatment of the rats with alloxan diabetes with the synthetic antioxidant BHT in a dose of 30 mg/kg bw prevented activation of lipid peroxidation, substantially decreasing the blood glucose content. It is concluded that the alloxan-induced activation of lipid peroxidation plays an essential role in the mechanism of alloxan action.
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PMID:[Lipid peroxidation in the liver of rats with alloxan diabetes]. 670 7

A possible role for insulin in stimulating islet beta-cell replication was examined in neonatal rat pancreatic monolayer cultures. Addition of insulin to serum-free medium increased the mitotic index and stimulated dose-dependent increases in [3H]-thymidine incorporation in nuclei of islet beta-cells in aldehyde-thionine-stained autoradiographs. The effects of insulin were not associated with any significant changes in glucagon or somatostatin levels in the culture media. Multiplication stimulating activity (MSA), an insulin-like growth factor, was about 100-fold more potent than insulin: 3 ng/ml MSA stimulated a half-maximal increase in thymidine labeling of beta-cell (+63%, P less than 0.005), whereas 300 ng/ml insulin was required for a similar effect. The maximal effects of insulin and MSA were similar, and the combination of maximal stimulatory concentrations of MSA (30 ng/ml) and insulin (3000 ng/ml) was not more effective than either substance added alone, suggesting that both peptides act on the same mechanism(s) regulating beta-cell replication. Furthermore, an antibody to the insulin receptor did not prevent the stimulatory effects of either insulin or MSA on thymidine labeling of beta-cells. These results demonstrate that insulin can stimulate islet beta-cell replication directly, possibly through a receptor for MSA or another insulin-like growth factor.
Diabetes 1982 Feb
PMID:Insulin and multiplication stimulating activity (an insulin-like growth factor) stimulate islet (beta-cell replication in neonatal rat pancreatic monolayer cultures. 675 33

A method is described for the isolation of "proislets' from mouse foetal pancreas. Histologically, isolated proislets are composed of undifferentiated tissue which does not stain with aldehyde fuchsin. Following isotransplantation, proislets develop into well differentiated islets with beta cell granulation. In addition, isografts consisting of proislets harvested from 8 foetal mouse pancreases have the functional capacity to reverse Streptozotocin-induced diabetes. Proislets appear to represent foetal precursor islet tissue.
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PMID:The isolation and transplantation of foetal mouse proislets. 681 1

Chlorpropamide alcohol flushing (CPAF) in non-insulin-dependent diabetics (NIDDs) has been reported to be associated with a lower tendency to develop late complications. The flush was thought to be mediated by enkephalins and prostaglandins. Early studies could not correlate CPAF to increased levels of acetaldehyde in blood and the flush was not regarded as an antabuse-like reaction. In this study, the increase of plasma acetaldehyde during the flush in 13 CPAF positive diabetics was significantly (P less than 0.005) higher than in the 13 CPAF negative diabetics during a CPAF challenge test. The increase of plasma acetaldehyde was reduced to the level of CPAF negative diabetics in three CPAF positive diabetics when they were exposed to alcohol without premedication with chlorpropamide and they did not flush. The normal breakdown of ethanol to acetic acid via acetaldehyde appears to be inhibited by chlorpropamide in the flushers. Acetaldehyde measurement is an objective method to study the chlorpropamide alcohol flush and it appears superior to the measurement of skin temperature.
Diabetes 1981 Sep
PMID:Increase of plasma acetaldehyde. An objective indicator of the chlorpropamide alcohol flush. 726 73

We examined the effect of aldehyde-modified matrix macromolecules on mesangial cell function in vitro, using incubated rat glomerular mesangial cells. Laminin and fibronectin were modified by incubation for 24 h with 50 mM glycolaldehyde (GA), a highly reactive cross-linking glycation product, with or without equimolar aminoguanidine. GA-modified laminin and fibronectin caused marked inhibition of cell adhesion. Cell spreading was reduced on the GA-modified laminin. In contrast, the GA-modified fibronectin had no effect on cell spreading. The study of thymidine incorporation by mesangial cells showed that the GA-modified fibronectin had a diminished mitogenic activity against cells. The content of advanced glycation end-product (AGE), which was determined by fluorescence at 370 nm excitation and 440 nm emission wavelength, increased and intermolecular cross-links appeared in the GA-modified proteins. To a large extent, aminoguanidine restored the structural alterations and functional deteriorations described above. We conclude that GA-modified matrix proteins diminish their functional properties against mesangial cells and affect cellular functions.
Diabetes Res Clin Pract 1994 Feb
PMID:Effects of aldehyde-modified proteins on mesangial cell-matrix interaction. 801 60

Highly purified islets of Langerhans were prepared in the present study from adult pigs by collagenase digestion and density gradient purification. After overnight culture, the tissue was equilibrated with DMSO at 25 degrees C, supercooled to -7.5 degrees C, nucleated, slowly cooled at 0.25 degrees C/min to -40 degrees C, and stored at -130 degrees C. Then, after variable periods of storage, the islets were rapidly thawed at 37 degrees C. Postthaw actual islet and islet equivalent (150-microns sized islets) recovery were 75 +/- 7% and 66 +/- 4%, respectively. The frozen-thawed porcine islets maintained good morphology on histological staining by hematoxylin-eosin and aldehyde-fuchsin. Upon perifusion, basal insulin secretion was 43 +/- 10 and 67 +/- 18 pmol/L from noncryopreserved, control islets, and cryopreserved islets, respectively (P = 0.2). Peak insulin release at 16.7 mmol/L glucose was 85 +/- 28 pmol/L from noncryopreserved islets and 157 +/- 48 pmol/L from the frozen-thawed islets (P = 0.1). When 10 mmol/L theophylline was added to 16.7 mmol/L glucose, the secretion of the hormone peaked to 221 +/- 83 (control islets) and 479 +/- 140 pmol/L (cryopreserved islets, P = 0.1). Total insulin secretion differed significantly for the noncryopreserved and the cryopreserved islets at both 16.7 mmol/L (1412 +/- 306 vs. 3756 +/- 764 pmol/L, respectively, P = 0.007) and 16.7 mmol/L glucose plus 10 mmol/L theophylline (2161 +/- 371 vs. 7505 +/- 2075 pmol/L, respectively, P = 0.011). Normoglycemia was restored within 7 days from implantation in temporarily immunosuppressed (aL3T4 antibody) mice with streptozotocin-induced diabetes by transplanting 1500-2000 cryopreserved porcine islets under the kidney capsule. Mean survival time of frozen-thawed islet xenografts (39 +/- 3 days) was similar to that of noncryopreserved islet xenografts (43 +/- 6 days). This study demonstrates that cryogenic storage is feasible of isolated porcine islets, with the frozen-thawed pancreatic endocrine tissue maintaining morphological integrity and both in vitro and in vivo viability. Further studies are needed to define the effect of cryopreservation on the immunogenic properties of porcine islets.
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PMID:Cryogenic storage of isolated, purified porcine pancreatic islets. 810 68


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