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

Nitric oxide, a radical generated by the enzyme nitric oxide synthase (iNOS), may be an important mediator of beta-cell damage in early insulin-dependent diabetes mellitus. We have investigated the molecular regulation of iNOS in insulin-producing RINm5F cells. The data obtained suggest that iNOS is maximally induced in these cells by a 6-h exposure to IL-1 beta or TNF-alpha + IFN-gamma, but not by endotoxin. iNOS mRNA degradation is rapid and it is not affected by IL-1 beta. Interestingly, NO seems to induce a negative feedback on iNOS expression, probably by decreasing iNOS transcription.
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PMID:Studies on the molecular regulation of the inducible form of nitric oxide synthase (iNOS) in insulin-producing cells. 753 33

Interleukin-1 beta (IL-1 beta) has been suggested to mediate beta-cell destruction in insulin-dependent diabetes mellitus (IDDM) by inducing nitric oxide production. In this study, we assessed the levels of IL-1 beta and the inducible form of nitric oxide synthase (iNOS), using a semi-quantitative polymerase chain reaction assay, and performed determinations of nitrite accumulation and IL-1 beta bioactivity, on pancreatic islets isolated from 5- and 16-week-old female and male nonobese diabetic (NOD) mice and from nondiabetes prone NMRI mice. NOD mouse islets contained notable amounts of IL-1 beta mRNA. At 5 weeks of age, but not at 16 weeks, the values were higher in islets isolated from NOD females compared to males. The IL-1 beta bioactivity showed differences roughly reflecting the mRNA levels in the NOD mouse islets. In the NMRI mouse islets the IL-1 beta bioactivity was very low. The expression of iNOS mRNA increased in both male and female islets between 5 and 16 weeks of age. Immunocytochemistry of pancreatic sections indicated the presence of macrophages especially in the peri-insular area of the NOD mice which suggests that IL-1 beta was produced by macrophages. The levels of IL-1 beta activity and mRNA in freshly isolated islets from NOD 5-weeks-old females did not correlate to the iNOS mRNA content or to the nitrite production. However, after incubation with IL-1 beta in vitro, both NOD and NMRI islets responded with a marked increase in nitric oxide production.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of mRNA contents of interleukin-1 beta and nitric oxide synthase in pancreatic islets isolated from female and male nonobese diabetic mice. 753 71

Nitric oxide (NO) is believed to be an effector molecule that mediates interleukin (IL)-1 beta-induced destruction and dysfunction of pancreatic beta-cells. We have demonstrated that both exogenous NO and NO generated endogenously by IL-1 beta brought about apoptosis of isolated rat pancreatic islet cells as well as pancreatic beta-cell tumor-derived cell line HIT. This apoptosis was characterized by cleavage of DNA into nucleosomal fragments of 180-200 bp and morphologically by nuclear shrinkage, chromatic condensation, and apoptotic body formation. The IL-1 beta-induced internucleosomal DNA cleavage occurred in a time- and dose-dependent manner. Actinomycin D, cycloheximide, and nitric oxide synthase inhibitors inhibited the DNA cleavage, which was correlated with the amount of NO produced, indicating that NO produced by HIT cells themselves could mediate the apoptosis. Furthermore, in the presence of tumor necrosis factor (TNF)-alpha, large amounts of NO were produced by IL-1 beta and DNA cleavage occurred more noticeably, although TNF-alpha alone did not generate NO. Streptozotocin (STZ), a diabetogenic reagent containing a nitroso moiety, also released NO and induced internucleosomal DNA cleavage in HIT cells. These results suggest that NO-induced internucleosomal DNA cleavage is an important initial step in the destruction and dysfunction of pancreatic beta-cells induced by inflammatory stimulation or treatment with STZ.
Diabetes 1995 Jul
PMID:Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells. 754 May 72

An inducible nitric oxide (NO) synthase isoform (iNOS) is specifically induced in the beta-cells of interleukin (IL)-1 beta-exposed rat islets, suggesting a role for NO in the pathogenesis of type I diabetes. The aim of this study was to clone and characterize iNOS cDNA from cytokine-exposed islets. Neither NO production nor iNOS transcription could be detected in rat islets or in rat insulinoma RIN-5AH beta-cells cultured in the absence of cytokines. Addition of IL-1 beta alone or in combination with tumor necrosis factor-alpha induced a concentration- and time-dependent expression of the iNOS gene and associated NO production (measured as nitrite) from both islets and RIN cells. iNOS transcripts were cloned by reverse transcriptase-polymerase chain reaction from the cytokine-exposed rat islets and RIN cells, and DNA sequence analysis revealed a near 100% identity to the recently published iNOS cDNA cloned from cytokine-exposed rat hepatocytes and smooth muscle cells. Recombinant rat islet iNOS was transiently and stably expressed in human kidney 293 fibroblasts, and the high enzymatic activity was inhibited by addition of the L-arginine analogs, N omega-nitro-L-arginine methyl ester and aminoguanidine. Two-dimensional gel electrophoresis revealed the recombinant iNOS as a series of spots with the expected molecular mass of 131 kDa and pI values in the range of 6.8 to 7.0. In conclusion, the IL-1 beta-induced iNOS cloned and expressed from rat islets and RIN cells is encoded by the same transcript as the iNOS induced in other cell types.
Diabetes 1995 Jul
PMID:Cloning and expression of cytokine-inducible nitric oxide synthase cDNA from rat islets of Langerhans. 754 May 73

Peripheral blood mononuclear cells from patients with non-insulin-dependent diabetes mellitus (NIDDM) show reduced proliferative response to phytohemagglutinin (PHA) and other mitogens. This study was undertaken to determine whether this reduced lymphocyte proliferation is mediated by a decreased production of cytokine or decreased expression of interleukin-2 receptor (IL-2R). Mononuclear cells from NIDDM patients (n = 34) and healthy controls (n = 22) were cultured in RPMI-1640 media containing PHA, concanavalin-A and phorbol myristate acetate. NIDDM patients showed reduced [3H]thymidine uptake (57% of controls, P < 0.01), reduced percentage of IL-2R-positive cells (61% of controls, P < 0.02) and increased level of tumor necrosis factor (TNF)-alpha (200% of controls, P < 0.05). The percentage of complement receptor (CR) 3-positive monocytes from NIDDM patients was also decreased (72% of controls, P < 0.05). However, the production of IL-1 beta, IL-2 and interferon-gamma, the percentages of pan T cells (CD3), T helper cells (CD4), T suppressor cells (CD8), the ratio of CD4/CD8 and the expression of CR1 and Fc receptors for immunoglobulin G (Fc gamma RII and Fc gamma RIII) were not significantly different between NIDDM patients and healthy subjects. Human recombinant IL-2 was unable to restore the [3H]thymidine uptake by PHA-stimulated mononuclear cells from NIDDM patients. Elevation of glucose concentration up to 27.8 mmol/l in the culture medium did not suppress the [3H]thymidine uptake and IL-2R expression by activated lymphocytes from healthy subjects. The decreased expression of IL-2R on activated lymphocytes might be responsible for the insufficient lymphocyte proliferation in NIDDM patients. These findings suggest that decreased expression of CR3 on monocytes, decreased lymphocyte proliferation and decreased IL-2R expression despite a higher production of TNF-alpha may explain the impaired cell-mediated immunity seen in NIDDM patients.
Diabetes Res Clin Pract 1995 May
PMID:Decreased cell-mediated immunity in patients with non-insulin-dependent diabetes mellitus. 758 21

Interleukin-1 beta (IL-1 beta) is a polypeptide produced by a variety of cells of hematological, dermal and neural origin. We have investigated the effect of type I diabetes mellitus and insulin treatment on tissue levels of IL-1 beta using streptozotocin (STZ)-treated mouse as an animal model. Diabetes affected IL-1 beta in a tissue specific manner. For example, IL-1 beta levels (as measured by ELISA) were markedly decreased in the liver and spleen of the STZ diabetic mice. In contrast, the levels of this cytokine remained unalatered in other tissues including kidney, testis, hippocampus and pituitary. Insulin treatment restored the diabetes-related decreases in liver and spleen IL-1 beta levels. Overall, the present data suggest that the abnormalities in hepatic and splenic IL-1 beta levels may contribute, at least in part, to the immunodeficiency and increased susceptibility to infection in diabetes mellitus.
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PMID:Insulin-dependent reduction in hepatic and splenic contents of interleukin-1 beta in experimental diabetes. 759 Jun 11

Nitric oxide (NO) may be a mediator of beta-cell damage in insulin-dependent diabetes mellitus. beta-Cells express the inducible form of NO synthase (iNOS) and produce large amounts of NO upon exposure to cytokines. iNOS requires the amino acid arginine for NO formation. It has been shown in other cell types that interferon-gamma (IFN gamma) and bacterial lipopolysaccharide induce the enzyme argininosuccinate synthetase (AS), enhancing the capacity of these cells to regenerate arginine from citrulline and maintain NO production in the presence of low arginine concentrations. To characterize the messenger RNA (mRNA) expression of AS in insulin-producing cells, RINm5F cells (RIN cells) were exposed to interleukin-1 beta (IL-1 beta) or to tumor necrosis factor-alpha plus IFN gamma. After 4-6 h, there was a significant and parallel induction of AS and iNOS mRNA. IL-1 beta-induced AS and iNOS mRNA expression was prevented by an inhibitor of the activation factor NF-kappa B pyrrolidine diaminoguanidine, an inhibitor of gene transcription (actinomycin D), and a blocker of protein synthesis (cycloheximide), suggesting coregulation of AS and iNOS by cytokines. RIN cells exposed to IL-1 beta in the presence of citrulline but the absence of arginine had increased AS enzyme activity and produced NO, demonstrating that cytokine-induced AS mRNA expression is accompanied by increased AS activity. Both adult rat islets exposed to IL-1 beta and human pancreatic islets cultured in the presence of IL-1 beta, tumor necrosis factor-alpha, and IFN gamma were able to use citrulline to regenerate arginine and produce NO. Taken as a whole, the present data suggest that regulation of AS activity may play a role in modulation of NO production in both rodent and human insulin-producing cells.
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PMID:Expression of the citrulline-nitric oxide cycle in rodent and human pancreatic beta-cells: induction of argininosuccinate synthetase by cytokines. 762 52

Cytokines, in particular interleukin 1 beta (IL-1 beta), have been implicated in pancreatic beta-cell destruction in insulin-dependent diabetes mellitus. In the rat prolonged exposure in vitro of islets of IL-1 beta leads to nitric oxide formation, impaired glucose metabolism and inhibition of insulin secretion. Interleukin 4 (IL-4) has been shown to be able to modulate nitric oxide formation in other cell systems. In the present study we have investigated the effect of IL-4 alone and in combination with IL-1 beta on islet cells. For this purpose isolated rat pancreatic islets were cultured for 42 h in medium supplemented with 0, 0.1, 1.0 or 10 ng/ml of human IL-4 in the absence or presence of 25 U/ml of IL-1 beta during the last 24 h of culture. IL-4 alone dose-dependently decreased the islet glucose oxidation rate and the glucose-stimulated insulin release. Furthermore, the cytokine potentiated IL-1 beta-induced reduction in the islet DNA content and (pro)insulin biosynthesis rate. The medium nitrite accumulation, as an index of nitric oxide formation, was not influenced by IL-4 (10 ng/ml) alone, whilst IL-1 beta stimulation of medium nitrite was partly reduced by IL-4. Compared to the action exerted by IL-1 beta the inhibitory action of IL-4 on rat islet function was moderate, and the latter action seems to be independent on nitric oxide production.
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PMID:Interleukin 4 impairs rat pancreatic islet function in vitro by an action different to that of interleukin 1. 764 Mar 49

Markers of cell-mediated immune activation were studied in 32 Chinese patients with recent-onset insulin-dependent diabetes mellitus (IDDM) as compared with 12 patients with recent-onset non-insulin-dependent diabetes mellitus (NIDDM) and 34 normal subjects. Sera were assessed for soluble markers of T-cell activation (sCD4, sCD8, sIL-2R); the cytokines (IL-1 beta, TNF-alpha, IL-2, IL-6), and T-cell subsets were also determined. Only 1 of the 32 IDDM patients had increased sCD4 levels, 5 had increased sCD8, and 3 had increased sIL-2R. None of the sera from NIDDM patients and control subjects showed such increased levels of soluble markers. Three IDDM patients had detectable IL-1 beta and this weakly so (< 3.5 pg/ml). However, the other cytokine data and the frequency of activated T-cells, CD4+, CD8+ T-cell subsets and CD4:CD8 ratio showed no significant differences among the IDDM, NIDDM and normal subjects. Our data suggest that in addition to a low frequency of islet cell antibodies, Chinese patients with recent onset IDDM also showed a lack of serum markers of cellular activation.
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PMID:Soluble T-cell markers and serum cytokines in type I (insulin-dependent) diabetes mellitus. 764 84

Many clinical and experimental data are in favour of a participation of leukocytes in vascular disease. Diabetes, a risk factor, is associated with a dysfunction of neutrophils. If chemotaxis and phagocytosis are deficient, it is not clearly established whether superoxide generation is conserved in these patients. We have measured this function in 35 noninsulin dependent diabetic patients, compared with a control population. We have assessed, in parallel, a profile of the cytokines involved in vascular phenomenons including TNF alpha, IL-1 beta et IL-6. Our results indicate that the generation of free radicals is normal in diabetics, with a significant elevation of TNF alpha. These results suggest a possible participation of this cytokine in the modulation of granulocyte reactivity.
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PMID:[Respiratory burst of neutrophils and cytokine profile in the non-insulin-dependent diabetic]. 765 Apr 34


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