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

Normal DBA2 mice become highly diabetic after infection with the EMC virus. But 500 R X-irradiation before infection inhibits the increase of mean blood glucose levels thus indicating the participation of immune reactions in the appearance of diabetes.
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PMID:[Does the diabetes caused by viral infection in mice depend on immune reactions?]. 19 22

The participation of immune reactions in the EMC virus induced diabetes of the mouse was studied by immunosuppression with 500 R sublethal X-irradiation or 120 mg/kg Asta 5122, a cyclophosphamide derivative. Average glucose levels after X-irradiation and infection remained normal, while virus, infected, otherwise untreated mice, had significantly higher mean glucose levels, indicating that immune reactions are necessary for the development of virus induced diabetes. Immune suppression by the cyclophosphamide derivative led, in contrast, to a significantly increased mean glucose level and increased insulitis in comparison with the controls only infected. This indicates an important role of the cellular immune reaction, insulitis in the destruction of the islets.
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PMID:Virus induced diabetes and the immune system. I. Suggestion that appearance of diabetes depends on immune reactions. 19 23

The infection of normal DBA2 and BALB/C nu/ + mice with 2 X 10(2,6) TCID50 of the M variant of the EMC virus induced pathological mean glucose values of 426 +/- 99 mg/100 ml in DBA2 mice and 292 +/- 130 mg/100 ml in BALB/C nu/ + mice on day five following infection. As diabetic animals died afterwards, mean glucose values decreased in the surviving animals on day seven and fourteen. The infected immunodeficient BALB/C nu/nu mice with thymus aplasia did not show abnormal mean glucose values or higher standard deviation of the means (114 +/- 37 mg/100 ml) when compared to uninfected controls (117 +/- 23 mg/100 ml). This demonstrates that a complete thymus-dependent immune system seems to be necessary for the development of the acute stage of virus-induced diabetes in the mouse.
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PMID:Virus induced diabetes and the immune system. II -- Evidence for an immune pathogenesis of the acute phase of diabetes. 22 66

Genetic factors and environmental factors are thought to be involved in the pathogenesis of insulin-dependent diabetes mellitus Type 1. Viruses, as one environmental factor, may act as primary injurious agents to beta cells or as triggering agents for autoimmunity. Some viruses such as EMC-D and Coxsackie B4 can induce Type 1 diabetes by infecting and destroying beta cells in genetically susceptible mice. In addition, certain species of monkey, such as Patas, show elevated blood glucose levels and depressed insulin secretion after infection with Coxsackie B4 virus. An occasional case of Type 1 diabetes mellitus appears to be associated with the infection of beta cells with Coxsackie B viruses. In addition, Coxsackie B4 virus may also generate viral antigen-specific cytotoxic T cells which may cross-react with a beta cell-specific autoantigen leading to autoimmune Type 1 diabetes. In the case of viral triggering of autoimmune Type 1 diabetes, certain viruses (eg, retrovirus in NOD mice and rubella virus in hamsters and humans) may alter a normally existing beta cell antigen into an immunogenic form or might induce a new antigen, leading to beta cell-specific autoimmune insulin dependent diabetes mellitus. In addition, other viruses (eg, Kilham's rat virus in DR-BB rats) could generate antigen-specific T effector cells which may cross-react with a beta cell-specific autoantigen. In contrast to the induction of diabetes, viruses can prevent the development of diabetes. Inoculation of DP-BB or NOD mice with lymphocytic choriomeningitis virus reduced the incidence of diabetes or prevented the disease by disordering particular lymphocyte subsets.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction and prevention of type 1 diabetes mellitus by viruses. 129 46

The development of IDDM results from the destruction of pancreatic beta cells. Genetic factors, various immune system alterations, and environmental factors have been studied as the possible causes of IDDM. The concordance rate for developing IDDM between monozygotic twins approaches 50%, suggesting that genetic factors are necessary, but nongenetic factors such as various immune system alterations and environmental factors also influence the clinical expression of genetic susceptibility. Environmental factors (e.g., viruses, chemicals, and diet) affecting the induction of diabetes may act as primary injurious agents which damage pancreatic beta cells or as triggering agents of autoimmunity. Certain viruses including EMC-D and Mengo virus 2T can directly infect pancreatic beta cells and replicate in the cells. The replication of viruses in the beta cells results in the destruction of the cells within 3 days, and the infected mice develop a diabeteslike syndrome in 3-4 days without the involvement of autoimmunity. In contrast, rubella virus appears to be somewhat weakly associated with autoimmune IDDM in hamsters. In addition, endogenous retrovirus expressed in pancreatic beta cells is clearly associated with the development of insulitis and diabetes in NOD mice. In man, there appears to be no correlation between the detection of islet cell autoantibodies and anti-Coxsackie B viral antibodies in newly diagnosed IDDM. In contrast, persistent infection of CMV and rubella virus appears to be associated with the presence of autoantibodies in newly diagnosed IDDM patients. It is particularly noteworthy that human CMV can induce islet cell autoantibodies that react specifically with a 38 kDa islet cell protein which may represent islet cell-specific antigens in a proportion of CMV-associated IDDM cases. These observations suggest that the association of diabetes with Coxsackie B viruses might be due to cytolytic infection of the beta cells with no link to autoimmunity, while both rubella virus and CMV are probably associated with autoimmune IDDM. A number of structurally diverse chemicals including alloxan, streptozotocin, chlorozotocin, Vacor, and cyproheptadine are diabetogenic mainly in rodents and sometimes in man. Possible mechanisms for beta cell destruction by these chemicals include (a) generation of oxygen free radicals and alteration of endogenous scavengers of these reactive species; (b) breakage of DNA and a consequent increase in the activity of poly-ADP-ribose synthetase, an enzyme depleting nicotinamide adenine dinucleotide in beta cells; and (c) inhibition of active calcium transport and calmodulin-activated protein kinase activity. (ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The role of viruses and environmental factors in the induction of diabetes. 207 86

Pancreatic islets from SJL/J mice infected with the D variant of encephalomyocarditis virus (EMC-D virus) showed lymphocytic infiltration with moderate to severe destruction of beta cells. Immunohistochemical staining of the islet sections with several monoclonal antibodies, anti-Mac-1, anti-Mac-2, and F4/80 for macrophages, anti-L3T4 for helper/inducer T cells, and anti-Lyt2 for cytotoxic/suppressor T cells revealed that the major population of infiltrating cells at the early stage of viral infection was Mac-2-positive macrophages. In contrast, macrophages detected by anti-Mac-1 and F4/80 monoclonal antibodies were not found at the early stage of viral infection but were found at intermediate and late stages of viral infection. Helper/inducer T cells and cytotoxic/suppressor T cells also infiltrated the islets at intermediate and late stages of viral infection. Short-term treatment of mice with silica prior to viral infection resulted in an enhancement of beta-cell destruction, leading to the development of diabetes. In contrast, long-term treatment of mice with silica resulted in complete prevention of diabetes caused by a low dose of viral infection and a significant decrease in the incidence of diabetes caused by an intermediate or high dose of viral infection. Furthermore, depletion of macrophages by a specific monoclonal antibody (anti-Mac-2) resulted in a much greater decrease in the incidence of diabetes caused by an intermediate dose of viral infection. However, suppression of helper/inducer T cells and cytotoxic/suppressor T cells, by anti-L3T4 and anti-Lyt2 antibodies, respectively, did not alter the incidence of diabetes. On the basis of these data, it is concluded that macrophages, particularly Mac-2-positive macrophages, play a crucial role in the process of pancreatic beta-cell destruction at the early stage of encephalomyocarditis D virus infection in SJL/J mice.
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PMID:Role of macrophages in the pathogenesis of encephalomyocarditis virus-induced diabetes in mice. 217 63

B10.BR, DBA/2, and BALB/c by J mice were infected with Trypanosoma brucei rhodesiense (Lou Tat clone 1). Subsequent infection with the D variant of encephalomyocarditis virus (EMC-D) resulted in no diabetes or encephalitis, even in the susceptible DBA/2 and BALB/c by J strains. Low levels of circulating interferon (IFN) were detected in trypanosome-infected mice at the time of EMC-D infection. All strains were severely immunosuppressed as a result of trypanosome infection, as evidenced by decreased virus-specific neutralizing antibody titers, compared to virus-infected controls. We attempted to simulate some aspects of T.b. rhodesiense infection in B10.BR mice by pretreating mice with cyclophosphamide and IFN prior to EMC-D infection. Immunosuppression by cyclophosphamide greatly enhanced the pathogenesis of EMC-D, while IFN protected against the diabetogenic effect of this virus. Our results indicate that: (i) T.b. rhodesiense infection inhibited EMC-D-induced diabetes, (ii) this inhibition was not due solely to the immunosuppression generated by the trypanosome infection, and (iii) IFN generated by the trypanosome infection could play some protective role in the inhibition of EMC-D-induced diabetes by trypanosome infection.
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PMID:Trypanosoma brucei rhodesiense infection in mice prevents virus-induced diabetes: possible role of interferon and immunological mechanisms. 243 62

The D variant of encephalomyocarditis (EMC-D) virus does not induce the production of interferon (IFN) and produces an insulin-dependent diabetes mellitus (IDDM)-like syndrome in certain mouse strains. In contrast, the B variant (EMC-B) virus, which is serologically identical to EMC-D virus, is a good inducer of IFN and is nondiabetogenic. It has been postulated that IFN may play a major role in determining the ability of these two viruses to infect pancreatic beta-cells. However, recent studies have shown that ICR Swiss and BALB/cByJ male mice are not protected by IFN against EMC-D virus-induced IDDM. Furthermore, treatment of these two strains of mice with anti-IFN gamma-globulin before infection with EMC-B virus does not result in diabetes. These observations suggest that mechanisms other than the IFN system are involved in determining the ability of the viruses to infect and destroy beta-cells. Studies were initiated to identify other mechanisms of action. In this communication, we show that up to six times more EMC-D than EMC-B virus attaches to primary beta-cells extracted from male ICR Swiss mice. This difference in ability to attach to beta-cells may account for the difference in the diabetic potential of this mouse strain.
Diabetes 1989 Sep
PMID:Differing attachment of diabetogenic and nondiabetogenic variants of encephalomyocarditis virus to beta-cells. 247 77

The D variant of encephalomyocarditis virus (10(1)-10(5) PFU/head) was intraperitoneally inoculated into 4 species of small rodents, rats, mice, Syrian hamsters, and Mongolian gerbils, and the susceptibility of these animals to EMC virus was examined virologically and histopathologically 3 days after infection. Viral replication was detected in the brain (mice), in the heart (mice and gerbils), and in the pancreas (mice, hamsters, and gerbils). No viral replication was detected in rats. Histopathological changes were seen in the brain (mice and hamsters), in the heart (mice and gerbils), and in the pancreas (mice, hamsters, and gerbils). No histopathological changes were seen in rats. The present results suggest that it may be quite possible to produce EMC virus-induced diabetes mellitus not only in mice but also in hamsters and gerbils.
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PMID:Susceptibility of four species of small rodents to encephalomyocarditis (EMC) virus infection. 255 52

The thymus-dependence of the encephalomyocarditis (EMC-M) virus induced diabetes has been demonstrated in comparative studies of normal and immunodeficient mice. Since the lymphocytic infiltration in the islets of Langerhans is modest during the virus infection, we have looked for possible indications of humoral immune mechanisms. Using fluorescence microscopy the presence of immunoglobulins in the islets could be shown 3 days after EMC-M-virus inoculation, gradually disappearing about day 14. The Ig deposit is scattered throughout the islets, but the precise target of Ig's has not been detected. Circulating islet cell surface reactive antibodies were demonstrable from the fourth day until about the third week. This period coincides largely with the period in which Ig deposits were present. Virus antibodies in peripheral blood could not be detected until the fifth day after the virus inoculation, whereas virus could be isolated from the third day. Beginning from day 5, about one third of the mice developed severe hyperglycaemia with blood glucose levels up to 35 mmol/l. Lymphocyte subsets of spleen cells were measured using a fluorescence activated cell sorter. Six days after virus inoculation the mean percentage of Lyt 2-positive (suppressor/cytotoxic) cells decreased below the value for control mice (p less than 0.05), but increased significantly (p less than 0.02) 2 weeks later.
Diabetes Res 1987 Jun
PMID:Prodromal immune manifestations in EMC-M virus induced diabetes: islet bound and circulating antibodies, and changes in lymphocyte subsets. 282 Jun 45


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