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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 fast axonal transport was examined in streptozotocin rats with 4 weeks duration in diabetes. Tritiated leucine and 14C-labelled glucosamine were injected into the fifth lumbar ganglion and TCA-soluble as well as insoluble activity were measured in segments of the sciatic nerve at various time intervals. (1) Time from injection until start of fast axonal transport was prolonged in diabetic rats whereas anterograde transport velocity was unchanged. (2) Incorporation of labelled leucine was reduced by 40%, whereas labelled glucosamine incorporation was unchanged. (3) Alterations observed in accumulations of labelled glycoconjugates proximal and distal to a collection crush might represent a decreased amount of retrograde transported material. The changes found in protein and glycoconjugate synthesis and transport could be related to the early reduction in axon calibre and conduction velocity in peripheral nerve of streptozotocin-diabetic rat.
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PMID:Axonal transport in early experimental diabetes. 9 May 40

Recently, evidence has been reported to suggest that human platelets like several other circulating blood cells may bind insulin. To examine whether human platelets contain specific insulin receptors, washed human platelets suspended in Hepes buffer were incubated at 24 degrees C with 125I-insulin in the presence and absence of unlabeled insulin and specific insulin binding was determined. Insulin binding by platelets increased progressively with time of incubation to reach a maximum at 3 h and was proportional to the number of platelets in the incubation mixture. Maximum insulin binding was observed at pH 8. Insulin degradation by platelets as assessed by TCA precipitability and reincubation studies was minimal. Scatchard analysis of the binding data and dissociation studies revealed evidence of negative cooperativity of the platelet insulin receptor. A high affinity dissociation constant of approximately equal to 3 X 10(9) M-1 was determined and the concentration of platelet insulin receptors was estimated as 25 binding sites/micron2 platelet surface area. Binding of 125I-insulin by platelets was inhibited by unlabeled porcine insulin and to a lesser extent by catfish insulin and porcine proinsulin but not by glucagon, prolactin, growth hormone, and thrombin. The findings indicate that human platelets contain specific insulin receptors. The significance of the platelet insulin receptor, particularly with respect to altered platelet function in diabetes mellitus, remains to be determined.
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PMID:Demonstration and partial characterization of insulin receptors in human platelets. 44 28

Higher omega-oxidation activities in the diabetic mammal and the starved one suggest that omega-oxidation mechanism plays an important role under these conditions. Dicarboxylic acid that is the final product of omega-oxidation can be metabolized further by beta-oxidation, subsequently, formation of succinyl-CoA and short-chain dicarboxylic acid might be increased in the liver. The physiological significance of omega-oxidation might consist in supplying the substrate of TCA cycle for utilization of acetyl-CoA and excreting the short-chain dicarboxylate in urine resulting in the decrease of ketone bodies in the blood, especially in diabetes and starvation. On the bases of these information, it is important to investigate the metabolism of dicarboxylic acids. Generally, fatty acids must be activated before they enter the metabolic pathway. By in vitro studies with rat liver homogenate, we have recently demonstrated that octadecaned-ioic acid must be activated by ATP-Mg2+ and CoA as monocarboxylic acid is. However, it has not been studied to compare the activity of acyl-CoA synthetase on mono and dicarboxylic acid. So, in this report, we assayed the activity of acyl-CoA synthetase in beef liver preparations using palmitic or hexadecanedioic acid (C1;16) as substrate. The results are as follows 1) Activation capacity of the supernatant of sonicated mitochondria was less than that of sonicated microsome for either palmitate or hexadecanedioate. 2) Activation capacity for hexadecanedioate was less than that for palmitate in both supernatant of sonicated mitochondria and that of sonicated microsome. 3) In our experiment, it might be suggested that the subcellular distribution of hexadecanedioate activation is almost identical with that of palmitate activation.
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PMID:[Acyl-CoA synthetase activity of long-chain mono and dicarboxylic acid in beef liver preparations (author's transl)]. 94 21

PGE1 has been found to improve the symptoms of diabetic neuropathy. We considered that a PGI2 derivative may also have a similar action and therefore studied its effect in diabetic rats. Iloprost was administered intraperitoneally to streptozotocin-induced diabetic rats at a dose of 10 micrograms/kg/day for a month. The changes in nerve conduction velocity (NCV) were measured in the tail. One day after the last dose of iloprost, both sciatic nerves were removed from each rat, homogenized, and extracted with 6% TCA. The sorbitol and myo-inositol concentrations were determined by a combination of HPLC and an enzymatic method. Cyclic AMP (cAMP) levels were determined by RIA, and Na+, K+ ATPase activity was assessed by the enzyme cycling method of Greene and Lattimer. Iloprost was found to improve the NCV in the diabetic rats. The sorbitol content was not affected by iloprost, but the myo-inositol content was higher in the iloprost group than in the untreated group, although the difference was not statistically significant. The Na+, K+ ATPase activity and cAMP content were significantly higher in the iloprost group than in the untreated group. These findings suggest the possibility that the cAMP-dependent protein kinase (A-kinase) system has an important influence on improvement in Na+, K+ ATPase activity.
Diabetes Res Clin Pract 1992 Nov
PMID:Effect of a prostaglandin I2 derivative (iloprost) on peripheral neuropathy of diabetic rats. 128 52

Hemoglobin A1c was studied by means of isoelectric focusing in borate-polyol system and modified albumin--using electrophoresis of blood serum on acetate-cellulose films with subsequent TCA-ethanol sedimentation in healthy volunteers and patients with diabetes mellitus. These parameters were increased in the patients, whereas content of the albumin was decreased and the content of hemoglobin A1c was altered only slightly during treatment of diabetes. Content of hemoglobin A1c and modified albumin was shown to depend on the compensation state of diabetes mellitus.
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PMID:[Level of hemoglobin A1c and modified blood serum albumin in patients with diabetes mellitus]. 194 83

Human recombinant interleukin-2 (IL-2) was labelled with Iodine-123 using modified Bolton and Hunter method. Separation from free iodine was performed by gel filtration chromatography using a Sephadex G10 column. HPLC analysis of labelled IL-2 showed that 98% of TCA precipitable radioactivity eluted in a single peak. The immunoreactivity of 123I-labelled IL-2 was determined by divert binding using the Fluorescence Activated Cell Sorter (FACS) and by receptor binding assay of IL-2 to activated lymphocytes. To demonstrate in vivo binding to activated lymphocytes, 123I-labelled IL-2 was injected intravenously into a newly diagnosed diabetic BB/Wistar rat. Higher radioactivity was detected in the pancreas and in the lymph nodes of the BB/W rat compared to a normal rat. These preliminary data show that 123I-labelled IL-2 retains its immunoreactivity and capacity to bind to activated lymphocytes both in vitro and in vivo and may be used for in vivo localization of lymphocytic infiltration in Type 1 diabetes.
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PMID:Labelling of interleukin-2 (IL-2) with 123-iodine with retention of its capacity to bind to activated lymphocytes. 349 31

The continuously growing, insulin-secreting cell line RINm5F does not respond to glucose with increased rates of insulin secretion and cell proliferation. The possibility that retinoic acid, which acts as a differentiating agent in several cell systems, could induce such responses to glucose has been investigated. Retinoic acid (10(-6)-10(-5) mol/l) failed to affect the cell viability, cell proliferation, 3H-thymidine incorporation or the DNA contents of the cultured RINm5F cells, irrespective of the glucose concentration of the culture medium. The insulin release was not affected either by glucose or by retinoic acid. Higher concentrations of the drug (10(-4) mol/l) proved toxic to the cells. The incorporation of 3H-mannose and 3H-glucosamine into TCA precipitable material of the RINm5F cells was strongly decreased by an increased glucose concentration of the medium. The incorporation of 3H-mannose, but not that of 3H-glucosamine, into macromolecules which could be precipitated with Concanavalin A or wheat germ lectin was diminished by retinoic acid (10(-5) mol/l).
Diabetes Res 1986 May
PMID:Effects of retinoic acid on growth, insulin secretion, and hexose incorporation into macromolecules of a continuously growing, insulin-secreting cell line (RINm5F). 352 18

There is mounting evidence suggesting functional and structural alterations in the retinal pigment epithelium (RPE) in experimental and clinical diabetes. In this study we examined the effect of high glucose concentrations on human RPE cells in vitro. After 24-hr incubation in media supplemented with glucose (19.5 mM, 25.5 mM, and 45.5 mM) and prepared both with and without osmotic adjustment, there was no significant effect on [3H]thymidine or [3H]uridine incorporation into TCA-precipitable material. There was, however, a significant decrease in [35S]methionine incorporation which became more marked with increasing glucose concentrations. This could not be attributed to increased osmolarity caused by the additional glucose as it occurred in isosmolar high glucose media. 3-O-methyl glucose, a non-metabolized glucose analog, did not have the same effect, suggesting that metabolism of glucose may be important. Resolution of newly synthesized proteins by gel electrophoresis and autoradiography suggests a generalized decrease in protein synthesis. These data suggest that elevated glucose levels cause a significant metabolic alteration in RPE cells in vitro.
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PMID:High glucose concentrations inhibit protein synthesis in retinal pigment epithelium in vitro. 365 82

The axonal transport of proteins in crushed nerves of streptozotocin (40 mg/kg) diabetic rats was investigated 4 weeks after induction of diabetes. 35S-methionine was used as a marker for protein and 3H-fucose as a marker for glycoprotein. The precursors were injected into the fifth lumbar spinal ganglion and the accumulation of TCA-insoluble activity proximal and distal to a sciatic nerve ligature was measured at different time intervals after application of a crush. The start of accumulation distal to the ligature was delayed by 1 hour for proteins as well as for glycoproteins. Furthermore, the total amount of accumulated protein after 19 h was decreased by 18% while the decrease was 21% for glycoprotein. By insulin treatment the differences could both be prevented and reversed after 3 days of normoglycaemia. These findings demonstrate an impaired response to a nerve crush and might be the explanation for the regenerative abnormalities of peripheral nerves in diabetes.
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PMID:Impaired retrograde axonal transport from a nerve crush in streptozotocin diabetic rats. 615 94

Collagen catabolism has been measured in skins of streptozotocin-induced diabetic rats. For measuring catabolism of collagen synthesized de novo during the diabetic state, we measured the amounts of [3H]hydroxyproline-containing degradation products in skins of diabetic rats, killed 4 h after [3H]proline injection (protocol 1); degradation products were isolated in TCA-soluble fractions of skin homogenates. For measuring catabolism of collagen preexisting before the induction of the diabetic state, we measured the 21-day loss of [3H]hydroxyproline (and hydroxyproline) in entire skins of rats that were streptozotocin-treated after [3H]proline injection (protocol 2). A 2.5-fold increase in the relative amounts of [3H]hydroxyproline-containing degradation products was measured in the TCA-soluble fractions of skins from diabetic rats (protocol 1). These degradation products had a low molecular weight (as evident from their diffusibility), and they were derived from recently synthesized collagen, possibly procollagen (as evident from their high [3H]hydroxyproline specific activity). Furthermore, they were not derived from the degradation of [3H]hydroxyproline-labeled collagen present before induction of the diabetic state (protocol 2). Evidence for this conclusion is as follows: the amounts of [3H]hydroxyproline-containing degradation products in skins of diabetic rats were not greater than that in skins of control rats, despite a 50% resorption of collagen in skins of diabetic rats. Overall, the catabolism of collagen formed de novo during the diabetic state was distinguished from the catabolism of collagen formed before, and both catabolic processes were enhanced in rat skins of streptozotocin-induced diabetic rats.
Diabetes 1982 May
PMID:Skin collagen metabolism in the streptozotocin-induced diabetic rat. Enhanced catabolism of collagen formed both before and during the diabetic state. 621 1


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