Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genotypic abnormalities of the renin-ANG system have been suggested as a risk factor for the development of diabetic nephropathy. Cleavage of angiotensinogen is the rate-limiting step in the activation of the renin-ANG system. The TT genotype of a polymorphism encoding threonine instead of methionine (M235T) has been associated not only with increased plasma angiotensinogen concentration but also with essential hypertension. In addition, a polymorphism in the angiotensinogen gene substituting methionine for threonine (T174M) has been associated with hypertension in nondiabetic populations. We studied the relationship between these polymorphisms in the angiotensinogen gene in IDDM patients with diabetic nephropathy (121 men, 74 women, age 40.9 +/- 10 years, diabetes duration 27 +/- 8 years). There was no difference in M235T genotype distribution between IDDM patients with diabetic nephropathy and those with normoalbuminuria: 73/97/25 (37/50/13%) vs. 67/95/23 (36/52/12%) had MM/MT/TT genotypes, respectively. No difference in distribution of T174M genotypes between nephropathic and normoalbuminuric IDDM patients was observed either: 148/44/1 (77/23/0.5%) vs. 141/42/2 (76/23/1%) had TT/TM/MM genotypes, respectively. In patients with nephropathy, systolic blood pressure was higher (161 +/- 22 mmHg [mean +/- SD]) in patients carrying TT genotype of the M235T angiotensinogen polymorphism as compared with patients with MM or MT genotypes (150 +/- 23 mmHg; P = 0.03). We conclude that neither the M235T nor the T174M polymorphism in the angiotensinogen gene contributes to genetic susceptibility to diabetic nephropathy in white IDDM patients, whereas the TT genotype of the M235T is associated with elevated blood pressure in patients with diabetic nephropathy.
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PMID:Angiotensinogen gene polymorphisms in IDDM patients with diabetic nephropathy. 859 44

Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease in which cytokines are thought to play an important role in beta-cell destruction and immune regulation. A major target of beta-cell autoimmunity in IDDM is the enzyme glutamate decarboxylase (GAD). We hypothesized that cytokines in the insulitis lesion modulate the synthesis of GAD. This may, in turn, modify the rate of beta-cell destruction. Accordingly we cultured rat islets in the presence and absence of cytokines, and measured synthesis of both isoforms of GAD, GAD65 and GAD67, by [35S]methionine incorporation and immunoprecipitation with a rabbit antiserum that recognizes both GAD65 and GAD67. Incubation of islets with interleukin (IL)-1 beta (1 ng/ml, 24 h), tumour necrosis factor alpha (TNF-alpha; 200 units/ml, 24 h) or interferon gamma (IFN-gamma; 500 units/ml, 72 h) significantly decreased the synthesis of both GAD65 and GAD67, but reduced neither total protein synthesis nor insulin accumulation in the medium or content. Incubation of islets for 24 h in IFN-alpha (1000 units/ml), TNF-beta (50 ng/ml), IL 2 (1000 units/ml), IL-4 (100 ng/ml), IL-6 (10 ng/ml), IL-10 (20 ng/ml), IL-12 (10 ng/ml) or transforming growth factor beta 2 (TGF-beta 2; 5 ng/ml) did not significantly alter GAD65 or GAD67 synthesis. Inhibition of GAD65 and GAD67 protein synthesis by IL-1 beta, TNF-alpha or IFN-gamma was reversed by co-incubation with the nitric oxide synthase inhibitor, NG-monomethyl arginine (NMMA). Expression of both GAD65 and GAD67 mRNA, measured by RNase protection assay, was also decreased by IL-1 beta and completely restored to baseline levels by NMMA. Thus the synthesis of both isoforms of islet GAD is selectively decreased in the presence of IL-1 beta, TNF-alpha or IFN-gamma by a NO-mediated mechanism, probably at the level of cytokine gene transcription. As GAD autoimmunity has been previously shown to have a pathogenic role in an animal model of IDDM, its inhibition by cytokines might limit the immune response, thereby regulating the rate of beta-cell destruction in IDDM.
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PMID:Cytokine regulation of glutamate decarboxylase biosynthesis in isolated rat islets of Langerhans. 876 Mar 54

Premature cardiovascular disease is common in insulin-dependent diabetic (IDDM) patients who develop diabetic nephropathy. Genetic polymorphism within the renin-angiotensin system has been implicated in the aetiology of a number of cardiovascular disorders; these loci are therefore candidate genes for susceptibility to diabetic renal disease. We have examined the angiotensin converting enzyme insertion/deletion polymorphism and angiotensinogen methionine 235 threonine polymorphism in a large cohort of Caucasian patients with IDDM and diabetic nephropathy. Patients were classified as having nephropathy by the presence of persistent dipstick positive proteinuria (in the absence of other causes), retinopathy and hypertension (n = 242). Three groups were examined for comparison: ethnically matched non-diabetic subjects (n = 187); a geographically defined cohort of newly diagnosed diabetic patients (n = 341); and IDDM patients with long duration of disease (> 15 years) and no evidence of overt nephropathy (n = 166). No significant difference was seen in distribution of angiotensin converting enzyme or angiotensinogen genotypes between IDDM patients with nephropathy and recently diagnosed diabetic subjects (p = 0.282 and 0.584, respectively), nor the long-duration non-nephropathy diabetic subjects (p = 0.701 and 0.190, respectively). We conclude that these genetic loci are unlikely to influence susceptibility to diabetic nephropathy in IDDM in the United Kingdom.
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PMID:Examination of two genetic polymorphisms within the renin-angiotensin system: no evidence for an association with nephropathy in IDDM. 887 96

Islet cell antigen (ICA) 512 also termed IA-2 is a novel autoantigen of type 1 diabetes, which has a tyrosine phosphatase-like domain. We have assessed autoantibody RIAs using a series of ICA512/IA-2 constructs to produce in vitro synthesized 35S-methionine-labeled proteins. Levels of ICA512/IA-2 (256-979, truncated aminoterminus) autoantibodies were strongly correlated with those of the full-length ICA512/IA-2 (1-979) autoantibodies (r = 0.96, P < 0.0001) and ICA512/IA-2 (687-979) autoantibodies (r = 0.98, P < 0.0001). RIAs using these 3 constructs had increased sensitivity relative to our initially reported ICA512 autoantibody RIA (amino acids 389-948, truncated carboxy- and aminoterminus). Only 2 of 38 sera examined in this study reacted with an aminoterminus ICA512/IA-2 (1-577) construct. The mean SD score (SD score = (index of unknown sample-mean index of controls)/SD of controls) using the ICA512/IA-2 (256-979) construct was significantly higher than the SD score obtained with other ICA512/IA-2 constructs (P < 0.001). Amongst patients with new-onset diabetes and prediabetic relatives, using RIAs for autoantibodies reacting with ICA512/IA-2 (256-979), insulin, and glutamic acid decarboxylase 65, 98% expressed one or more of these autoantibodies and 78% expressed two or more, whereas no control (n = 208) expressed more than a single autoantibody. A combined ICA512/IA-2 (256-979), glutamic acid decarboxylase 65 autoantibody RIA with differential autoantigen labeling (35S-methionine, 3H-leucine) has been developed that uses 96-well plate membrane filtration and Top Counter beta counting. Concordance between results of dual and single RIAs was greater than 90%. This simple combined autoantibody assay should facilitate large-scale autoantibody screening.
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PMID:Evaluation of islet cell antigen (ICA) 512/IA-2 autoantibody radioassays using overlapping ICA512/IA-2 constructs. 902 21

Autoantibodies to 65 kD glutamic acid decarboxylase (GADAA) and ICA512 (ICA512AA) were measured by radioimmunoassays using as antigens in vitro transcribed and translated [35S]-methionine-labeled human GAD65 and ICA512 (IA-2). The prevalence of GADAA and ICA512AA in sera from 87 patients with IDDM was 39 and 23%, respectively. The frequency and titer of ICA512AA declined sharply within 5 years after the onset of IDDM. Among patients tested within 4 years after diagnosis, the prevalence of ICA512AA was significantly higher in acute onset IDDM than in slowly progressive IDDM (37 versus 6%, P < 0.025) irrespective of age, while there was no difference in GADAA frequency between acute onset and slowly progressive subtypes (51 versus 63%). A total of two patients out of 121 patients with NIDDM were positive for GADAA, and two other NIDDM patients, who were suffering from sarcoidosis, were positive for ICA512AA. Neither of the antibodies were positive in sera from four atypical NIDDM patients, aged < 20 years, who showed ketosis at onset and required insulin followed by excellent metabolic control with diet restriction alone. These observations suggest that ICA512AA are associated with rapid progression of beta cell damage in IDDM. ICA512 radioassay, in combination with GAD assay may provide a useful diagnostic marker for IDDM especially in youth.
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PMID:Combined measurements of GAD65 and ICA512 antibodies in acute onset and slowly progressive IDDM. 917 63

The GM2-1 islet ganglioside has been sequenced, found to be a novel ganglioside structure with a sialic acid moiety in the terminal position and two residues of non-acetylated galactosamine and also shown to be a target of autoantibodies in a subset of ICA+ relatives of type 1 diabetic patients who subsequently progressed to the overt disease. In the present study we determined whether antibodies to GM2-1 or to other pancreatic gangliosides (a) are also expressed at disease onset and (b) are correlated with other diabetes-associated autoantibodies. Pancreatic gangliosides were extracted from human pancreas and purified by thin layer chromatography (TLC). Anti-ganglioside autoantibodies were determined using an indirect immunoperoxidase technique performed directly on TLC plates in the following groups of patients: (a) newly diagnosed type 1 diabetic subjects before insulin therapy (n = 45); all were tested for GAD65 autoantibodies in a fluid-phase RIA using 35S-methionine-labelled recombinant human GAD65. Of these patients, 24 were also tested for insulin autoantibodies (IAA) by a competitive fluid phase radioimmunoassay and 21 were tested for GAD67 reactivity. (b) Forty-two age- and sex-matched normal control subjects. Autoantibodies to GM2-1, but not to other pancreatic gangliosides (GM3, GD3, GD1a), were expressed in 31 of 45 new-onset type 1 diabetic subjects and in one of 42 normal controls (P < 0.01), while anti-GAD65, IAA and anti-GAD67 were found in 31 of 45, 12 of 24 and three of 21 patients respectively, but not in the control group of subjects. Interestingly, occurrence of GM2-1 autoantibodies was significantly correlated (P < 0.005) with positivity for GAD65 autoantibodies, but not for IAA or GAD67 autoantibodies. It is of note that both GAD and gangliosides are mainly expressed in islets and in neuronal tissues and, therefore, type 1 diabetes may be regarded as a neuroendocrine autoimmune disease.
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PMID:Autoantibodies to the GM2-1 islet ganglioside and to GAD-65 at type 1 diabetes onset. 945 98

Serum paraoxonase is a glycoprotein which binds to high-density lipoproteins (HDL) and may prevent oxidation of LDL by hydrolyzing lipid peroxides. Two polymorphisms identified in the paraoxonase gene (Met-Leu 54 and Gln-Arg 192) have been associated with cardiovascular disease. Oxidative low-density lipoprotein (LDL) is also toxic to retinal capillary endothelial cells and pericytes, so that mildly modified LDL may contribute to the development of diabetic retinopathy. To investigate the potential significance of these polymorphisms in the pathogenesis of diabetic retinopathy in IDDM, 80 patients with diabetic retinopathy and 119 controls without diabetic retinopathy were investigated in the current project. The allelic frequency of leucine 54 (L) was significantly higher in the group with retinopathy than without retinopathy (73% vs. 57%, p < 0.001). The genotype L/L was strongly associated with the development of diabetic retinopathy (p < 0.001), but a similar association was not found with Gln-Arg 192. Leucine 54 is a risk factor for diabetic retinopathy.
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PMID:A variant of paraoxonase (PON1) gene is associated with diabetic retinopathy in IDDM. 966 50

Graves' disease is characterized by the presence of autoantibodies to the thyrotropin receptor (TSHR), which are pathogenic and responsible for disease activity. It is well recognized that the autoantibodies are heterogeneous and recognize a number of different conformational dependent epitopes on the TSHR. In this study, we have extended our previous observations to study the interaction of Graves' disease autoantibodies with TSHR ectodomain produced by in vitro transcription and translation reaction. The specific activity of the translated TSHR ectodomain has been increased by a log fold by adding an efficient ribosome binding Kozak sequence before the translation initiation codon as well as double labelling with 35S-methionine and 35S-cysteine during the translation reaction. Addition of canine pancreatic microsomes to the translation mix showed that the glycosylation of TSHR ectodomain did not occur efficiently for the nascent receptor protein. In order to determine the specificity and sensitivity of the improved assay with nonglycosylated TSHR ectodomain, we have studied 331 sera from Graves' disease patients and as controls 100 sera from patients with nonthyroid autoimmune disorders as well as sera from 200 normal control subjects with no family history of thyroid autoimmunity. With this large cohort of sera from Graves' disease and control individuals, 25% of Graves' disease sera immunoprecipitated the dual labeled, in vitro transcribed and translated TSHR ectodomain, exceeding the 98th percentile of the control sera. There was no correlation between the autoantibodies that immunoprecipitate the in vitro translated TSHR ectodomain and those that inhibit iodinated TSH binding in the radioreceptor assay and those with biological activity in a bioassay. The data are consistent with the finding that a proportion of Graves' disease autoantibodies can interact directly with TSHR ectodomain produced by in vitro transcription and translation. However, in contrast to the wide use of similar translation and immunoprecipitation assays to measure other autoantibodies for the diagnosis of autoimmune disorders, such as type 1 diabetes, the TSHR immunoprecipitation on its own is unsuitable for diagnosis of Graves' disease.
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PMID:Direct binding of thyrotropin receptor autoantibody to in vitro translated thyrotropin receptor: a comparison to radioreceptor assay and thyroid stimulating bioassay. 1036 78

Type I diabetes mellitus results from the autoimmune destruction of insulin producing beta cells in the pancreas. Certain viral infections, especially those caused by coxsackie B viruses and related enteroviruses, have been associated with the development of type I diabetes. The sequence homology between the coxsackie B4 virus nonstructural protein 2C (CVB4 p2C) and the major diabetes autoantigen glutamic acid decarboxylase (GAD(65)) provides a basis for the hypothesis of molecular mimicry. In this study, we investigated the prevalence of antibodies directed against nonstructural enterovirus proteins. In addition, a correlation of antibodies against CVB4 p2C and GAD(65) was studied in diabetes patients and in healthy controls. Antibody reactivity against CVB proteins was detected by immunoprecipitation of [(35)S]-methionine-labelled viral proteins and GAD(65) antibodies were measured in a quantitative radio-immunoassay. It was shown that antibodies raised against the nonstructural proteins of CVB4 are very common in the population and a high degree of heterotypic cross-reactivity exists between different enterovirus types. CVB4 p2C-specific antibodies were not only detectable in GAD(65) antibody-positive diabetes patients but also in GAD(65) antibody-negative healthy blood donors. Furthermore, GAD(65) antibodies could not be detected in p2C-positive subjects who had various enterovirus infections, indicating that an antibody response to CVB4 p2C does not necessarily induce a cross-reactive immune response against GAD(65). A correlation was not found between antibodies against GAD(65) and p2C.
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PMID:Analysis of antibody responses against coxsackie virus B4 protein 2C and the diabetes autoantigen GAD(65). 1045 65

The tyrosine phosphatase like protein IA-2 is an important autoantigen in insulin-dependent diabetes mellitus (type 1 diabetes). Autoantibodies to IA-2 (IA-2A) are present in the serum of patients with type 1 diabetes even before the onset of the disease. Previously, we reported on a radioimmune assay to detect IA-2A, using E. coli-derived 125I-labelled IA-2 as antigen. Although this assay could be shown to be equivalent to the common reference method for IA-2A detection (radioligand assays using in vitro synthesised 35S-methionine labelled antigen), the disadvantages of both assays with respect to synthesis and handling of the radioactive antigen limit their use in routine laboratories. In this study, we have evaluated a non-radioactive enzyme-linked immunosorbent assay (ELISA) for the simple detection of IA-2A. We report on an ELISA where the biotinylated intracytoplasmic part of IA-2 (IA-2ic) is captured on streptavidin-coated plates. The sensitivity of the ELISA was similar to the validated radioligand assay, as it detected 47 of 69 (69%) patients with type 1 diabetes as compared to 46 of 68 (67 %) with the reference method for IA-2A detection (radioligand assays using in vitro synthesised 35S-methionine labelled antigen). Only 2 of 50 (4%) patients with autoimmune thyroid disease and 1 of 114 (1 %) healthy controls were detected in the ELISA, confirming specificity. There was a significant correlation between the ELISA and the radioligand assay (r = 0.64, p<0.001). We conclude that this ELISA is suitable to detect IA-2A in the serum of patients with type 1 diabetes with a similar sensitivity and specificity to the radioligand assay. This ELISA will allow rapid and simple measurement of IA-2A where the radioligand assay is inconvenient or not available.
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PMID:Detection of autoantibodies to the diabetes-associated antigen IA-2 by a sensitive enzyme-linked immunosorbent assay. 1066 23


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