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

The BB rat provides an excellent animal model for type 1 (insulin-dependent) diabetes mellitus. Cytotoxic autoantibodies against pancreatic beta cells have been found in the sera of both patients with type 1 (insulin-dependent) diabetes and BB rats. These antibodies have been implicated in the pathogenesis of the disease. In this study, a monoclonal autoantibody, designated KT1, has been developed by the fusion of spleen cells from a BB rat and a mouse myeloma cell line. KT1 was found to be of the immunoglobulin M isotype and reacted specifically with islet cells. In microcytotoxicity assays KT1 was shown to mediate complement-dependent lysis of approximately 30% of a rat insulinoma cell line and 25% of rat pancreatic islet cells in culture. It did not cause lysis of the other cell lines tested. KT1 has been demonstrated, by indirect immunofluorescence, to bind specifically to a cell surface antigen on live and acetone-fixed islet cell cultures from Wistar rat neonates and to rat insulinoma cells. Western blotting experiments revealed reaction to a 68-kDa protein from rat insulinoma cell extracts. This monoclonal antibody may have clinical relevance as it exhibits properties similar to the islet cell surface antibodies present in the sera of BB rats.
Diabetes Res Clin Pract 1990 Jan
PMID:A cytotoxic monoclonal autoantibody from the BB rat which binds an islet cell surface protein. 240 25

To investigate the autoimmune pathogenesis of spontaneously occurring diabetes mellitus in BB rats, spleen cells of newly diagnosed diabetic BB rats were fused with mouse myeloma cells. Hybridoma supernatants were screened for antibodies by indirect immunofluorescence and by 51Cr-release assays using the RINm5F rat insulinoma cell line. One clone, E5C2, produced an IgM kappa antibody that was cytotoxic for RINm5F cells, but not for other rat cell lines nor for primary rat islet cells. However, treatment of primary rat islet cells with neuraminidase exposed surface antigens and rendered the cells susceptible to complement-mediated lysis by antibody E5C2. Using immunostaining of glycolipids separated by thin-layer chromatography, hapten inhibition assays with defined carbohydrates, and Western blots, the antigens recognized by E5C2 on RINm5F cells were identified as glycoproteins with molecular weights of 60,000 and 68,000. The antibody recognizes a carbohydrate antigen containing the sequence Gal beta 1-4GlcNAc-R, which on RINm5F cells is predominantly hidden by covalently bound sialic acid. These studies raise the possibility that hidden antigenic determinants on islet cells exposed by a variety of means may be the target of autoimmune attack.
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PMID:Pancreatic islet cell surface glycoproteins containing Gal beta 1-4GlcNAc-R identified by a cytotoxic monoclonal autoantibody. 243 47

Dissociated human insulinoma cells were plated onto plastic multiwell dishes. Cells were maintained for 1 mo on plastic with three passages. Cultures consisted of small colonies with some areas of stratification and few intercellular spaces. Ultrastructural studies indicated that cultured cells had epithelial features with desmosomes at cell-to-cell contacts and intermediate filaments in addition to secretory granules in the cytoplasm. Insulin and C-peptide were released in equimolar amounts in culture media. When challenged for 30 min with 16.7 mM glucose, 1 mM 3-isobutyl-1-methylxanthine, 4 mM tolbutamide, or 10(-6) M glucagon, insulinoma cells responded by a 1.5-, 1.5-, 2-, or 3-fold increase, respectively, in insulin release above baseline levels. A 15-min challenge with 10(-5) M isoproterenol increased insulin secretion by 1.85-fold. By indirect immunofluorescence, an anti-insulin antibody reacted positively with cell cytoplasm, whereas anti-somatostatin and anti-glucagon antibodies did not. Insulinoma cell surface expressed class I MHC molecules but not class II molecules. Immediately after isolation, crude insulinoma cells were contaminated by 2% of DR+ cells from nonislet components that disappeared after several weeks in culture. The ability of insulinoma cells to stimulate allogenic T-lymphocyte proliferation was assessed by [3H]thymidine incorporation in mixed culture combinations. Crude insulinoma cells elicited a strong lymphoproliferative response with a stimulation index ranging between 3.5 and 7, whereas no stimulation was found after 1 mo in culture. It is postulated that absence of class II-positive cells in the stimulatory cell preparation conditioned this immune tolerance across the major histocompatibility barrier.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1988 Sep
PMID:Structure, function, and immunogenicity of human insulinoma cells. 245 30

Several lines of evidence suggest that islet-specific T cells are important in the pathogenesis of the insulitis resulting in insulin-dependent diabetes mellitus (IDDM). Therefore, we decided to analyze islet-specific T cell reactivity in the peripheral blood of IDDM patients. With the use of insulinoma membranes as antigen, T cell lines were generated from peripheral blood mononuclear cells of patients with recent onset of the disease. In a proliferation assay such T cell lines responded to insulinoma membranes and, though to a lesser extent, also to fibroblast membranes, the control antigen used. One of the T cell lines was cloned. Eight clones were isolated that respond to insulinoma antigens. Five of these eight clones appeared to be specific for insulinoma membranes, i.e. they demonstrated proliferation in response to insulinoma but not fibroblast membranes. These insulinoma-specific proliferative responses are HLA-DR restricted.
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PMID:Human T cell clones with specificity for insulinoma cell antigens. 246 3

Management of insulinopenic diabetic individuals centers on administration of insulin by means of multiple injections, a wearable or implantable insulin-infusion pump, or a whole-organ or segmental-pancreas transplant. Preliminary trials indicate that surgical implantation of a hybrid device containing living insulin-secreting tissue may function as a combined glucose sensor and insulin-infusion pump. By means of a chamber composed of a semipermeable membrane shaped into hollow fibers or a box surrounding endocrine tissue, pilot studies have shown that isolated islets of Langerhans, fragments of insulinoma, or a fetal pancreas retains function for days to weeks, as judged by the ability to sustain euglycemic conditions in chemically induced diabetic rats. Lacking clear proof that normalizing blood glucose levels will prevent vascular complications of diabetes in humans, the case for further development of a hybrid (tissue plus fabricated components) device rests mainly on optimistic extrapolation of results attained in the chemically induced diabetic rat and dog. For the minority of diabetic patients who have insulin-dependent diabetes, the benefit afforded by a bionic device establishing internal insulin release regulated by silently sensed blood glucose level is more than enough payoff for the discomfort and surgery involved in its implantation. Further trials of a hybrid artificial pancreas in the dog appear warranted as a logical extension of preliminary studies with this species.
Diabetes Care 1989 Jun
PMID:Toward a hybrid artificial pancreas. 249 44

IFN-gamma and TNF-alpha injure the pancreatic beta-cell and may be involved in the pathogenesis of autoimmune type 1 diabetes. Because the induction of IL-6 appears to be an important host cell response to injury, we have examined whether IL-6 is produced by murine pancreatic islets or rat insulinoma (RIN-m5F) cells after their exposure to IFN-gamma and TNF-alpha. Islet culture supernatants contained detectable IL-6 activity which was increased 6-fold when islets were exposed to IFN-gamma and 40- and 115-fold when islets were exposed to TNF-alpha and TNF-alpha + IFN-gamma, respectively. A mAb against murine IL-6 abolished (control and IFN-gamma) or significantly reduced (TNF-alpha and TNF-alpha + IFN-gamma) the IL-6 activity in islet supernatants. The magnitude for the effects of IFN-gamma and TNF-alpha on the production of IL-6 from mouse islets was found to be both time and dose dependent. Northern blot hybridization analysis of islet total cytoplasmic RNA with a cDNA probe to murine IL-6 revealed a band at 1.3 kb, the intensity of which increased in islets exposed to IFN-gamma + TNF-alpha. IL-6 activity was also detected in culture supernatants from RIN-m5F cells exposed to TNF-alpha + IFN-gamma. Islets cultured with rIL-6 secreted higher levels of insulin compared with control islets. Pancreatic islet cells, in all probability beta-cells, produce IL-6, the expression of which is up-regulated by IFN-gamma and/or TNF-alpha. In addition to a possible role in regulating pancreatic beta-cell function we propose that IL-6 produced by the pancreatic beta-cell may act as a costimulator for autoreactive B and T lymphocytes in autoimmune diabetes.
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PMID:Evidence for IL-6 production by and effects on the pancreatic beta-cell. 250 90

We experimented with a wide range of serum-free media to find the best one for culturing insulinoma cells from the Syrian golden hamster, cell line In-R1-I10. Optimum cell growth came with a mixture of equal proportions of Dulbecco's modified Eagle's medium and Ham's F-12, supplemented with 10(-6) M insulin, 10 micrograms/ml transferrin, and 10(-9) M triiodothyronine (what we labeled DF-ITT medium). In addition to testing different varieties of basal media, we also experimented with different concentrations of known stimulants of cell proliferation, including transferrin, ferrous sulfate, insulin, epidermal growth factor, triiodothyronine, hydrocortisone, monoethanolamine, prolactin, proteose peptone, and selenium. Cells cultured in DF-ITT medium grew as well as those in serum-containing medium for 94 consecutive generations. Their insulin secreting capacity was maintained. The substitution of epidermal growth factor (10 ng/ml) for the insulin did not reduce either the growth rate or the insulin secreting capacity of the culture cells.
Diabetes Res Clin Pract 1989 Jan 03
PMID:Serum-free culture of insulin-secreting clonal cells from a hamster insulinoma. 253 87

We have reported that enhanced levels of class I major histocompatibility complex (MHC) antigen are expressed throughout the islets of prediabetic and newly diabetic BB rats and that the endocrine cells of the islet remained class II negative. In this study we investigated the molecular biology of lymphokine-induced expression of the class I and II MHC genes in subclones of the rat insulinoma cell line RINm5F. Treatment of a particular subclone of RINm5F cells (which are normally class II negative, class I low expressors) with crude lymphokine preparation or various doses of recombinant interferon-gamma resulted in enhancement of MHC class I antigen expression but no detectable induction of class II antigen expression. This enhancement of class I antigen expression was a dose-dependent phenomenon and was preceded by a dose-dependent increase in class I-specific RNA. Both class I and II genes were induced at the transcriptional level, as determined by Northern blotting and in vitro nuclear transcription assays, but exhibited strikingly different induction kinetics. Supernatants from concanavalin A-stimulated splenocytes had a similar class I-restricted inductive effect on MHC gene expression. This subclone of RINm5F cells, which exhibits a class I lymphokine response-positive, class II response-negative phenotype, 1) mimics the behavior of beta-cells in the prediabetic and newly diabetic pancreas and 2) represents a valuable system for probing the similarities and differences in the lymphokine-mediated induction pathways for class I and II MHC genes.
Diabetes 1989 Jul
PMID:Interferon-gamma induces transcription and differential expression of MHC genes in rat insulinoma cell line RINm5F. 254 72

Insulin-dependent (type 1) diabetes mellitus (IDDM) is due to the selective autoimmune-mediated destruction of pancreatic beta cells possibly initiated by viruses. To elucidate the possible role of viruses and cytokines in the pathogenesis of IDDM, we have examined the effect of reovirus infection on beta cell major histocompatibility complex (MHC) expression and the effect of interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) on beta cell function in vitro. Infection of RIN-m5F (rat insulinoma) cells with reovirus-1 or reovirus-3 was associated with a tenfold increase in class 1 MHC protein and mRNA expression. Reovirus infection did not induced the expression of class 11 MHC by RIN-m5F cells. Exposure of reovirus to ultraviolet light almost completely abolished its ability to induce class 1 MHC protein expression on infected cells. Murine islets cultured for 3 days with IFN-gamma and/or TNF-alpha had a significantly reduced insulin response to glucose, which was more marked with a combination of the cytokines. During 6 days of culture in IFN-gamma plus TNF-alpha islets underwent noticeable degeneration associated with an 80% reduction in insulin content. These findings together with previous data suggest viruses and cytokines may have multiple roles in beta cell destruction, indirectly through enhanced MHC protein expression and directly through functional impairment and loss of viability.
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PMID:Viruses and cytokines: evidence for multiple roles in pancreatic beta cell destruction in type 1 insulin-dependent diabetes mellitus. 254 35

Vitamin A (retinol) is required for insulin secretion, and retinoic acid substitutes for retinol in this function. To determine if retinol acts at the beta-cell level, we assayed beta-cells of the rat insulinoma (RINm5F) line for cytosolic retinol- and retinoic acid-binding proteins (CRBP and CRABP) by radioimmunoassay (RIA) and [3H]retinol and [3H]retinoic acid binding to cytosol extracts. Furthermore, we tested whether insulin release from cells was affected by addition of retinol or retinoic acid to culture medium. RINm5F cells were grown to near confluence before assay of CRBP and CRABP. Scatchard analysis showed the Kd for retinol to be approximately 6 nM at a level of 4.5 pmol/mg protein or 300,000 sites/cell. Sucrose density-gradient assay showed single discrete peaks migrating at 2S for both retinol and retinoic acid. RIA of whole-cell extracts showed CRBP and CRABP levels of 5.27 +/- 0.41 and 2.95 +/- 0.75 pmol/mg protein, respectively. Retinol (1.75 microM) and retinoic acid (0.175 and 1.75 microM) increased KCl-induced insulin release. Considered together, the presence of CRBP and CRABP in a beta-cell line and the increase in KCl-induced insulin release by retinol and retinoic acid are consistent with the idea that retinol has a functional role in insulin secretion and suggest a potential mechanism of action at the beta-cell level similar to that observed in other retinoid-responsive cells.
Diabetes 1989 Dec
PMID:Cytoplasmic retinoid-binding proteins and retinoid effects on insulin release in RINm5F beta-cells. 255 41


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