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)

Recent reports have suggested that xamoterol, a beta 1 adrenoceptor partial agonist with 43% intrinsic sympathomimetic activity improves symptomatic postural hypotension in patients with primary autonomic failure. To evaluate the use of xamoterol in eleven insulin dependent patients with diabetes mellitus who had postural hypotension (over 20 mmHg systolic blood pressure) secondary to autonomic neuropathy, we performed a double-blind, randomized, placebo controlled crossover study with xamoterol (200 mg bd orally) for 1 month. Treatment with xamoterol raised supine systolic blood pressure by 11 mmHg but a reduced standing systolic blood pressure by 11 mmHg with an increase in the standing-supine systolic blood pressure difference. No significant differences were observed in symptom score, HbA1 or plasma glucose. We conclude that oral xamoterol raises supine systolic blood pressure but paradoxically lowers standing systolic blood pressure further in insulin dependent diabetes mellitus. Xamoterol is unlikely to be of value in the management of postural hypotension in diabetic patients with autonomic neuropathy.
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PMID:A double-blind crossover study of oral xamoterol in postural hypotension due to diabetic autonomic neuropathy. 168 39

Type 1 diabetes results from the destruction of insulin-producing pancreatic beta cells. Genetic and environmental factors are implicated in the beta cell destruction. As environmental factors affecting the induction of type 1 diabetes, diabetogenic viruses, chemicals, toxins, and diet are likely candidates as either primary injurious agents of beta cells or triggering agents for the induction of autoimmunity. Regarding viruses as a triggering factor of type 1 diabetes, there are at least two different pathogenic mechanisms in virus-induced diabetes: cytolytic infection of beta cells, leading to their destruction, and triggering of autoimmunity, leading to the autoimmune-mediated destruction of beta cells. Since there is no correlation between the induction of antibodies to Coxsackie B viruses and the presence of islet cell autoantibodies in patients with type 1 diabetes, the induction of diabetes by Coxsackie B viruses may be due to cytolytic infection of beta cells rather than an autoimmune response. In contrast, rubella virus and cytomegalovirus (CMV) do appear to be somehow associated with autoimmune type 1 diabetes since there is a strong correlation between the presence of islet cell autoantibodies and persistent infections. Regarding genetic factors, there are distinct markers related to the susceptibility to Coxsackie B4 virus-associated type 1 diabetes and CMV-associated type 1 diabetes. Four specific DNA restriction endonuclease fragments (BamHI-DQ-beta 6.6, TaqI-DR-beta 4.3, TaqI-DR-beta 2.5 and TaqI-DR-beta 1.5 kb) are related to the susceptibility to Coxsackie B4 virus-associated type 1 diabetes while six specific DNA restriction endonuclease fragments (BamHI-DQ-alpha 12.5, -beta 3.7 and -beta 3.2 kb, TaqI-DQ-alpha 7.2, -beta 7.2 and -beta 5.4 kb) are related to the susceptibility to CMV-associated type 1 diabetes.
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PMID:Viruses as a triggering factor of type 1 diabetes and genetic markers related to the susceptibility to the virus-associated diabetes. 268 Mar 67

The HLA genetic region consists of a large multigene complex which includes a number of highly homologous alpha and beta genes encoding class II polypeptides, clustered in three major loci, DP, DQ, and DR. Analysis of genomic polymorphisms at each of these loci is of considerable interest due to the role of particular structural polymorphisms in immune function, but this analysis has been hampered by difficulty in distinguishing between such highly homologous loci. We have identified locus-specific and exon-specific class II gene sequences in order to produce synthetic oligonucleotide probes which hybridize specifically to DQ beta genes. Two such oligonucleotide probes are described which are specific for the beta 1 and beta 2 exons of DQ (DC) beta, which identify DQ beta genes in digests of cellular DNA and which can be used to characterize restriction sites flanking the two oligonucleotide-specific regions. By sequentially hybridizing these probes in modified Southern analyses, we have been able to generate a tentative "restriction map" of a newly identified DQ beta allele from digests of total genomic DNA. This oligonucleotide mapping technique discriminates between two HLA-DQw3+ alleles, DQ3.1 and DQ3.2, permitting the recognition of structural polymorphisms with DQ beta which are highly associated with type I diabetes mellitus.
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PMID:Exon-specific oligonucleotide probes localize HLA-DQ beta allelic polymorphisms. 287 44

HLA class II genes have been implicated in susceptibility to a number of diseases. We have previously identified two allelic variants of DQw3 and have shown that DR4-DQ beta 3.2 haplotypes are associated with increased risk of IDDM whereas DR4-DQ beta 3.1 haplotypes are not. DR5 and DR8 DQw3+ individuals are exclusively DQ beta 3.1 and share numerous restriction sites within the DQ beta genes with DR4-DQ beta 3.1 individuals. In order to compare the DQ beta 3.1 genes associated with different haplotypes, we have sequenced coding and noncoding regions of the DQ beta genes from a DR4-DQ beta 3.1 HTC (ER) and a DR8-DQ beta 3.1 HTC (LUY). LUY and ER DQ beta genes share nucleotide substitutions in both the beta 1 and beta 2 exons, yielding six amino acid replacements distinguishing them from DQ beta 3.2. In the noncoding regions as well, LUY and ER share nucleotide substitutions distinguishing their DQ beta 3.1 genes from DQ beta 3.2. These data support the concept that the DQ beta 3.1 allele was introduced onto different backgrounds via homologous recombination.
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PMID:Molecular analysis of DQ beta 3.1 genes. 289 47

In order to assess the adrenergic contribution to hypoglycemic glucose counterregulation in type I diabetes mellitus and to determine whether the adrenergic contribution is mediated through beta 1- or beta 2-adrenergic receptors, hypoglycemia was induced by an i.v. insulin infusion (30 mU/m2 x min) for 60 min in 11 insulin-dependent diabetic patients (IDDM), 5 with normal plasma glucagon responses and 6 with blunted responses, and also in 7 age-weight-matched nondiabetic subjects. Rates of plasma glucose decrease and postnadir increase, as well as plasma concentrations of free insulin and of counterregulatory hormones, were measured when insulin was infused alone, and when insulin was infused along with propranolol (a beta 1- and beta 2-adrenergic receptor antagonist) or metoprolol (a selective beta 1-antagonist). Postnadir plasma glucose recovery was decreased in IDDM with blunted plasma glucagon responses (21 +/- 0.8 mumol x L-1 x min-1, P less than 0.001), but was normal in patients with normal plasma glucagon responses (30 +/- 0.4 versus 33 +/- 0.5 mumol x L-1 x min-1 in nondiabetic subjects, P = NS). Postnadir plasma glucose recovery was not affected by either propranolol or metoprolol in normal subjects and in IDDM with normal glucagon responses. However, in IDDM with blunted plasma glucagon responses, postnadir plasma glucose recovery was further decreased by propranolol (14 +/- 0.6 mumol x L-1 x min-1, P less than 0.01), but was unaffected by metoprolol (22 +/- 0.9 mumol x L-1 x min-1, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The adrenergic contribution to glucose counterregulation in type I diabetes mellitus. Dependency on A-cell function and mediation through beta 2-adrenergic receptors. 631 52

Upper-body obesity is an important risk factor for developing non-insulin dependent diabetes. To investigate the possibility that a lipolysis defect is present in this form of obesity, we examined the adrenergic regulation of lipolysis in abdominal subcutaneous fat cells from 25 women with upper-body obesity and 24 non-obese women. Lipolytic noradrenaline sensitivity (but not the maximum rate of lipolysis) was reduced by 10-fold in obese women (p < 0.01). The noradrenaline resistance could be ascribed to a 10-fold decrease in lipolytic beta 2-adrenoceptor sensitivity (p < 0.01). The lipolytic sensitivity of beta 1- and alpha 2-adrenergic receptors was normal in the obese women. A 70% reduction in the cell surface density of beta 2-adrenoceptors was observed compared to the control subjects (p < 0.01). However, beta 1-receptor density as well as steady-state mRNA levels for beta 1- and beta 2-receptors were normal in obese women. Lipolytic noradrenaline sensitivity correlated inversely with BMI (adjusted r2 = 0.76 together with fat cell volume in stepwise regression analysis). The fasting plasma level of free cortisol was 30% lower in obese compared to non-obese women (p < 0.05) but obesity did not influence resting plasma catecholamine levels. Thus, lipolytic catecholamine resistance is present in abdominal obesity, due to low density of beta 2-adrenoceptors, which in its turn may be caused by a post-transcriptional defect in beta 2-receptor expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Catecholamine resistance in fat cells of women with upper-body obesity due to decreased expression of beta 2-adrenoceptors. 774 23

This study has investigated the genetic basis of the heterogeneous autoimmune response to glutamic acid decarboxylase (GAD) in 179 Australian patients with IDDM. Antibodies to GAD have been correlated with HLA-DQB1 alleles and genotypes, as determined by sequence-specific oligonucleotide hybridizations after polymerase chain reaction was applied to exon 2 of the DQ beta 1 gene. HLA-DQ2 was significantly increased (p < 0.01) in IDDM patients with antibodies to GAD. Antibodies to GAD were detected in 64% of 72 DQ2.8 patients, in 55% of 29 DQ2.2 or DQ8.8 patients and in 41% of 78 patients with other HLA-DQB1 genotypes. HLA-DQ genotype association with autoimmunity to GAD was statistically significant (p = 0.02) and reflected early formation of antibodies to GAD, rather than an HLA association with persistence of antibodies to GAD, since the genotype effect was more evident (p = 0.02) in those with more recent onset (0-5 years) of IDDM. Also, the HLA-DQ genotype effect was more evident in patients with IDDM onset after the age of 14 years (p = 0.003). Multivariate analysis showed that HLA-DQB1 genotypes had a more significant impact on antibodies to GAD than either duration or age of onset of IDDM. In patients with IDDM in childhood, only a minority had low-risk HLA-DQB1 genotypes (37%) when compared with those with onset in adulthood (62%) (p = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:HLA-DQ genotypes are associated with autoimmunity to glutamic acid decarboxylase in insulin-dependent diabetes mellitus patients. 810 72

The cloning, sequencing and expression in model systems of the previously unidentified beta 3-adrenoceptor recently led to an extensive functional characterization. Ligand binding and adenylate cyclase activation studies helped define a specific profile that is quite distinct from that of the beta 1- and beta 2-adrenoceptors, but strongly reminiscent of most of the 'atypical' beta-adrenoceptor-mediated responses reported in earlier pharmacological studies. More recently, a naturally occurring variation in the human beta 3-adrenoceptor has been correlated with hereditary obesity and with increased dynamic capacity to add on weight and develop non-insulin dependent diabetes in Western obese patients. Donny Strosberg and France Pietri-Rouxel describe how results now provide a consistent picture of an important role for the human beta 3-adrenoceptor in the regulation of lipid metabolism and as an obvious target for drugs to treat some forms of obesity and diabetes.
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PMID:Function and regulation of the beta 3-adrenoceptor. 965 87

Recently, a newly identified human HERV-K18 like endogenous retrovirus (IDDMK(1,2)22) has been associated to the etiology of type I diabetes (IDDM). Although the exact mechanism remains unclear, it was postulated that the 3' end ORF product of the env gene of IDDMK(1,2)22 would trigger a V beta 7-specific human T cell expansion leading to their infiltration in the pancreas of afflicted patients and to the autoimmune destruction of the insulin-producing beta cells. Since then, such superantigen (SAg)-like activity as well as the association between the IDDMK(1,2)22 virus and IDDM pathogenesis have been challenged. To further characterize functionally the putative IDDMK(1,2)22-encoded SAg, we have cloned from human DNA the identical 462bp ORF sequence originally described. The IDDMK(1,2)22 ORF fragment was transfected in the same human B cell line (Raji) originally used as APC to demonstrate the V beta 7 specificity. The immunostimulatory potential of IDDM ORF was tested on murine T cell hybridomas and compared to the well-characterized mouse mammary tumor virus Mtv7 SAg transfected in the same conditions. A panel of 16 T cell hybridomas encompassing 14 different V betas was analyzed. We have failed to detect IDDMK(1,2)22-induced IL-2 production from any of these hybridomas, even those bearing the murine V beta 1 mV beta 1, V beta 4 or V beta 10 TcR beta chains which are most closely related to the human V beta 7 (hV beta 7). Our results suggest that IDDMK(1,2)22 ORF is devoid of superantigenic activity as defined by classical criteria.
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PMID:Human endogenous retrovirus IDDMK(1,2)22 and mouse mammary tumor virus superantigens differ in their ability to stimulate murine T cell hybridomas. 1184 50

Alleles of HLA class II genes DQB1, DQA1, and DRB1 in the MHC region are major determinants of genetic predisposition to type 1 diabetes (T1D). Several alleles of each of these three loci are associated with susceptibility or protection from disease. In addition, relative risks for some DR-DQ genotypes are not simply the sum or product of the single haplotype relative risks. For example, the risk of the DRB1*03-DQB1*02/DRB1*0401-DQB1*0302 genotype is often found to be higher than for the individual DRB1*03-DQB1*02 and DRB1*0401-DQB1*0302 homozygous genotypes. It has been hypothesized that this synergy or epistasis occurs through formation of highly susceptible trans-encoded HLA-DQ(alpha 1, beta 1) heterodimers. Here, we evaluated this hypothesis by estimating the disease associations of the range of DR-DQ genotypes and their inferred dimers in a large collection of nuclear families. We determined whether the risk of haplotypes in DRB1*0401-DQB1*0302-positive genotypes relative to the DRB1*03-DQB1*02-positive genotypes is different from that of DRB1*01-DQB1*0501, which we used as a baseline reference. Several haplotypes showed a different risk compared to DRB1*01-DQB1*0501, which correlated with their ability to form certain trans-encoded DQ dimers. This result provides new evidence for the potential importance of trans-encoded HLA DQ molecules in the determination of HLA-associated risk in T1D.
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PMID:Genotype effects and epistasis in type 1 diabetes and HLA-DQ trans dimer associations with disease. 1516 2


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