Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Tumour necrosis factor gene polymorphism has been proposed as a determinant of Type 1 (insulin-dependent) diabetes mellitus. Tumour necrosis factor-beta gene polymorphisms were analysed in 40 North Indian Asian Type 1 diabetic patients and 63 control subjects. A 5.5 kilobase gene fragment was significantly increased among the patients (82.5% vs 52%, pc less than 0.01). A 10.5 kilobase fragment was significantly reduced among the patients (70% vs 90.5%, pc less than 0.02). The 5.5 kilobase fragment was associated with DR3, and was not significantly increased among DR3-positive patients compared with DR3-positive control subjects. The 5.5 kilobase/5.5 kilobase genotype was increased among the diabetic subjects (30% vs 9.5%, pc less than 0.03). The 10.5 kilobase/10.5 kilobase genotype was reduced among the diabetic subjects (17.5% vs 47.5%, pc less than 0.02). The 5.5 kilobase/10.5 kilobase genotype was not significantly associated with disease. These findings contrast with those in a white Caucasian population, suggesting that tumour necrosis factor-beta polymorphisms do not predispose to Type 1 diabetes directly, but are in linkage disequilibrium with disease susceptibility alleles at other MHC loci.
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PMID:Tumour necrosis factor-beta polymorphism is unlikely to determine susceptibility to type 1 (insulin-dependent) diabetes mellitus. 168

Tumour necrosis factors alpha and beta (TNF-alpha and TNF-beta) and gamma interferon (IFN-gamma) were measured by ELISA in the supernatants of phytohaemagglutinin (PHA)-activated peripheral blood mononuclear cells (PBMNC) from 98 individuals (60 controls and 38 patients with insulin-dependent diabetes mellitus [IDDM]). The PBMNC were incubated with varying concentrations of PHA (0, 1, 5, and 10 micrograms/ml) for 72 h. In our population study we observed a correlation between the levels of secretion of TNF-alpha and IFN-gamma but not TNF-beta. The complete data set was analysed by non-parametric tests, and no associations with HLA phenotypes existed. Reduced levels of TNF-beta, but not TNF-alpha or IFN-gamma, secretion were found in IDDM patients stimulated with 1 and 5 micrograms/ml of PHA (P = 0.001 and 0.02 respectively). None of the lymphokine secretion levels at any PHA concentration correlated with particular HLA phenotypes. Analysis of the natural log-transformed data indicated that only for the TNF-beta levels (at 5 micrograms/ml PHA) could subjects be divided into high and low secretors, which also did not correlate with a particular HLA-B or -DR antigen.
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PMID:The effect of HLA and insulin-dependent diabetes mellitus on the secretion levels of tumour necrosis factors alpha and beta and gamma interferon. 212 64

Following activation peritoneal macrophages from diabetes prone BB rats secreted strikingly higher amounts of tumour necrosis factor alpha than found for macrophages from diabetes resistant or normal Wistar rats. Enhanced tumour necrosis factor alpha production was detected prior to the occurrence of insulitis. Cultures of macrophages derived from precursor cells in diabetes prone BB rat bone marrow also showed upregulated tumour necrosis factor alpha secretion upon challenge with endotoxin and interferon gamma. Tumour necrosis factor alpha hypersecretion may contribute to autoimmune diabetes by affecting thymic and post-thymic T-cell maturation and by promoting pancreatic islet inflammation.
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PMID:Tumour necrosis factor alpha production is upregulated in diabetes prone BB rats. 225 35

Tumour necrosis factor (TNF) has been implicated in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). To investigate a possible role for TNF in IDDM we compared endogenous TNF production in two lines of non-obese diabetic (NOD) mice, NOD/Lt and NOD/WEHI, that have a high and low incidence of diabetes, respectively. Preliminary experiments had shown that the lower syngeneic mixed lymphocyte reaction (SMLR) in NOD/Lt mice could be corrected by TNF-alpha. Plasma TNF-alpha was measured in 8 week-old female non-diabetic mice primed with 1000 units IV of murine interferon gamma (IFN-gamma) followed after 3 hours by 5 micrograms IV of lipopolysaccharide (LPS). Two hours later plasma was collected and TNF measured by ELISA. Plasma TNF in NOD/Lt mice was 9.2 +/- 2.4 ng/ml (mean +/- SEM, n = 16) compared to 2.5 +/- 0.5 ng/ml in NOD/WEHI mice (n = 15) and 7.6 +/- 1.0 ng/ml in BALB/c mice (n = 14). Time course studies demonstrated higher levels of both immunoreactive and bioactive TNF in NOD/Lt compared to NOD/WEHI mice up to 4 hours post-stimulation. A separate group of female NOD/Lt mice had IFN-gamma/LPS-stimulated plasma TNF-alpha measured at 10 weeks and were followed to age 30 weeks. The mean stimulated plasma TNF-alpha level was consistently higher in those mice that developed diabetes compared to those that remained non-diabetic, the difference being significant when mice were 21 weeks of age. These results suggest that endogenous TNF-alpha production may be a trait marker of IDDM susceptibility.
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PMID:Endogenous TNF production differs between high and low diabetes incidence non-obese diabetic (NOD) mice. 785 1

Tumour necrosis factor (TNF) may be relevant to the pathogenesis of both pre-eclampsia and type 1 diabetes, and there is evidence than human TNF alpha responses to stimuli are HLA-DR dependent. To test the hypothesis that pre-eclampsia and diabetes may share a common immunogenetic susceptibility, 92 pre-eclampsia patients were compared with 264 general population controls. The relative frequencies of individual HLA-DR antigens in pre-eclamptics were found to correlate with reported relative TNF alpha responses for those antigens. Moreover, putative high responder HLA-DR1, DR3 and DR4 alleles were significantly (p < 0.001) more frequent in pre-eclampsia patients (79%) than in controls (59%). This hypothesis could explain the weak association between pre-eclampsia and diabetes and may help resolve the apparently conflicting literature on HLA in pre-eclampsia.
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PMID:HLA-dependent TNF secretory response may provide an immunogenetic link between pre-eclampsia and type 1 diabetes mellitus. 887 17

Insulin resistance is a feature of non-diabetic relatives of non-insulin-dependent diabetic (NIDDM) families. Tumour necrosis factor-alpha (TNF alpha) expression is linked with insulin resistance, and is under strong genetic control. We examined the relationship between insulin resistance and two polymorphisms of the TNF alpha promoter region (positions -238 and -308). Non-diabetic relatives (n = 123) of NIDDM families and control subjects (n = 126) with no family history of diabetes were studied. Insulin resistance was determined by homeostasis model assessment (HOMA) and short insulin tolerance test (ITT), and genotyping was by restriction digest. The -238 polymorphism (TNFA-A allele) was carried by 14 relatives and 11 control subjects, and all were heterozygotes. To examine the relationship between the -238 polymorphism and insulin resistance independent of potentially confounding factors, the relatives with the TNFA-A allele were individually pair-matched for age, sex, waist-hip ratio, body mass index, and glucose tolerance with relatives homozygous for the wild-type allele. Relatives with the TNFA-A allele had decreased insulin resistance (HOMA index: 2.0, 3.6 +/- 2.1 [means +/- SD of differences], p = 0.03), and this was true for comparable pair-matched control subjects (HOMA index: 1.1, 1.9 +/- 0.8, p = 0.01). Combining relative (n = 7) and control (n = 4) pairs that had undergone an ITT, subjects with the TNFA-A allele had an increased K(ITT) (3.8, 3.0 +/- 1.0%/min, p = 0.04) similarly indicating decreased insulin resistance. There was no significant relationship between the -308 polymorphism and insulin resistance. We conclude that the TNFA-A allele is associated with decreased insulin resistance as assessed by two independent methods, and may protect against the future development of NIDDM in susceptible individuals.
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PMID:Tumour necrosis factor-alpha gene promoter polymorphism and decreased insulin resistance. 956 47

1. Insulin resistance has been highlighted as a common causal factor for hypertension, hyperlipidaemia, diabetes mellitus and obesity, all of which are recognized to occur simultaneously, and a distinct clinical entity is defined as 'multiple risk factor syndrome'. 2. Recently, a new class of antidiabetic agents, thiazolidinediones (TZD) has been developed and has been shown to improve insulin resistance by binding and activating a nuclear receptor, peroxisome proliferator-activated receptor (PPAR) gamma. 3. cDNA of rat PPAR gamma 1 and gamma 2 were cloned and gene regulation of PPAR gamma in rat mature adipocytes was examined. Hydrogen peroxide, an oxygen radical, which is recognized to be the common intracellular signal for multiple risk factors, potently down-regulated PPAR gamma mRNA expression in rat mature adipocytes. 4. Tumour necrosis factor (TNF)-alpha, which is considered to play a role in obesity-induced non-insulin-dependent diabetes mellitus and to augment oxidative stress, also suppressed PPAR gamma expression. 5. Thiazolidinediones dose-dependently recovered TNF-alpha-induced down-regulation of PPAR gamma mRNA expression. 6. The modulation of PPAR gamma expression by TZD can be one mechanism for the improvement of insulin resistance by TZD. 7. Vascular tone and remodelling are controlled by several vasoactive autocrine/paracrine factors produced by endothelial cells in response to several vascular injury stimuli, including hypertension. The PPAR gamma gene transcript was detected in cultured endothelial cells. 8. The administration of TZD stimulated the endothelial secretion of type-C natriuretic peptide, which is one of the natriuretic peptide family and is demonstrated by us to act as a novel endothelium-derived relaxing peptide. 9. Concomitantly, TZD significantly suppressed the secretion of endothelin, a potent endothelium-derived vasoconstricting peptide. 10. Thiazolidinediones can affect vascular tone and growth by modulating the production of endothelium-derived vasoactive substances to influence occurrence and progression of hypertension and atherosclerosis.
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PMID:Hypertension and insulin resistance: role of peroxisome proliferator-activated receptor gamma. 1040 88

Insulin resistance in skeletal muscle is one of the earliest symptoms associated with non-insulin-dependent diabetes mellitus (NIDDM). Tumour necrosis factor (TNF) and nonesterified fatty acids have been proposed to be crucial factors in the development of the insulin-resistant state. We here show that, although TNF downregulated insulin-induced insulin receptor (IR) and IR substrate (IRS)-1 phosphorylation as well as phosphoinositide 3-kinase (PI3-kinase) activity in pmi28 myotubes, this was, unlike in adipocytes, not sufficient to affect insulin-induced glucose transport. Rather, TNF increased membrane expression of GLUT1 and glucose transport in these muscle cells. In contrast, the nonesterified fatty acid palmitate inhibited insulin-induced signalling cascades not only at the level of IR and IRS-1 phosphorylation, but also at the level protein kinase B (PKB/Akt), which is thought to be directly involved in the insulin-induced translocation of GLUT4, and inhibited insulin-induced glucose uptake. Palmitate also abrogated TNF-dependent enhancement of basal glucose uptake, suggesting that palmitate has the capacity to render muscle cells resistant not only to insulin but also to TNF with respect to glucose transport by GLUT4 and GLUT1, respectively. Our data illustrate the complexity of the mechanisms governing insulin resistance of skeletal muscle, questioning the role of TNF as a direct inhibitor of glucose homoeostasis in this tissue and shedding new light on an as yet unrecognized multifunctional role for the predominant nonesterified fatty acid palmitate in this process.
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PMID:Cross-talk mechanisms in the development of insulin resistance of skeletal muscle cells palmitate rather than tumour necrosis factor inhibits insulin-dependent protein kinase B (PKB)/Akt stimulation and glucose uptake. 1054 46

Vascular endothelial growth factor (VEGF) is the most important factor in the regulation of angiogenesis. Associated with luteinisation and formation of corpus luteum (CL) are alterations in luteal vascularity. The aim of the study was to test under in vitro conditions the stimulation of VEGF and progesterone (P) secretion of bovine granulosa cells by LH, IGF1 (insulin like growth factor) or by factors known to be produced by luteinised granulosa cells or in the early CL. Localisation of VEGF protein in preovulatory follicle and early CL were achieved by immunohistochemistry. LH and IGF1 stimulated dose dependently and significantly P and VEGF when tested alone. Both hormones added simultaneously had clear additive and even more interesting far greater (synergistic) effects on P with LH (0.1 ng/ml) plus 5 or 10 ng IGF1. In contrast, VEGF was stimulated only additively with 0.1 ng/ml of LH plus 5 or 10 ng IGF1. But with the higher dose of LH (1 ng/ml) additionally to the additive effect a tendency for a synergistic action (which was significant with 1 ng LH plus 5 ng IGF1/ml) was observed. Endothelin, oxytocin, progesterone, atrial natiuretic peptide, angiotensin II, prostaglandin F2 alpha alpha, prostaglandin E2, cortisol, fibroblast growth factor 1 and 2 and growth hormone showed no effect neither on P nor on VEGF. Tumour necrosis factor alpha (TNF alpha) stimulated (P < 0.05) VEGF with 10 or 100 ng/ml but not P. TPA (12-0 tetra decaenoyl-phorbol-13-acetate) or Ca2+ ionophore did not show a stimulatory effect in contrast to forskolin which increased P and VEGF secretion dose dependently. The VEGF protein was localised in follicle (granulosa cells, theca cells and some endothelial cells) and early (about 24 h after ovulation) CL (granulosa-lutein cells and endothelial cells). The same signalling pathway by stimulation of cAMP production and proteinkinase A activation for luteinisation and neo-vascularisation demonstrates a close temporal and spatial relationship of these normal physiological processes.
Exp Clin Endocrinol Diabetes 2001
PMID:Stimulatory and synergistic effects of luteinising hormone and insulin like growth factor 1 on the secretion of vascular endothelial growth factor and progesterone of cultured bovine granulosa cells. 1140 98

Tumour necrosis factor-alpha (TNF alpha) is a mediator of reactive oxygen species, which are implicated in endothelial dysfunction and atherosclerosis. Type II diabetes is associated with endothelial dysfunction and elevated circulating TNF alpha. We hypothesized that reducing serum levels of TNFalpha, using pentoxifylline, would improve endothelial function. Thirteen subjects [age 58+/-2 (S.E.M.) years] with Type II diabetes (disease duration 74+/-13 months) undertook a randomized, crossover study of 8 weeks pentoxifylline and 8 weeks placebo. Endothelium-dependent and-independent vasodilation in resistance arteries was assessed via bilateral forearm venous occlusion plethysmography during intra-brachial infusions of acetylcholine (ACh), sodium nitroprusside (SNP) and N(G)-monomethyl-L-arginine (L-NMMA). High-resolution ultrasound of the brachial artery in response to ischaemia was used to determine endothelium-dependent conduit vessel flow-mediated dilation (FMD), and endothelium-independent conduit function was assessed by sublingual administration of glyceryl trinitrate (GTN). Serum concentrations of TNF alpha were also determined. Pentoxifylline lowered serum TNF alpha from 4.1+/-0.7 to 2.9+/-0.6 pg x ml(-1) (P=0.001). Forearm blood flow (FBF) responses at each dose of ACh did not differ with treatment (P=0.4). Similarly, FBF responses to SNP (P=0.8) and L-NMMA (P=0.2) did not differ. There was also no significant difference in brachial artery diameter during FMD (P=0.2) or GTN administration (P=0.06). Despite lowering serum TNF alpha concentration, pentoxifylline at a dose of 400 mg three times a day for 8 weeks did not improve vascular function in either conduit or resistance vessels in this group of Type II diabetic subjects.
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PMID:Effect of lowering tumour necrosis factor-alpha on vascular endothelial function in Type II diabetes. 1214 8


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