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

To develop somatic gene therapy for diabetes, we studied an animal model with proinsulin-producing fibroblasts with an immunological safety system. Cultured mouse fibroblasts of the Ltk- cell line were transfected first with the efficient human proinsulin expression vector pBMG-Neo-Ins. Initially, 2 x 10(6) cells with a proinsulin-production rate of 91 ng.24 h-1.10(6) cells-1 were transplanted i.p. into streptozocin-induced diabetic C3H mice. The blood glucose concentrations improved between the first and the 28th day, but the animals died of hypoglycemia between the 29th and 46th days. The proinsulin-producing Ltk- cells were further transfected with a second plasmid, pHEBo-CD8.2, encoding BALB/c mouse T-cell differentiation antigen. The CD8.2 allotype is different from CD8.1 allotype by only one amino acid substitution and should be only slightly antigenic to the recipient C3H mice. Somatic gene therapy with these doubly transfected cells followed by the consecutive administration of a monoclonal antibody to CD8.2 resulted in an initial decrease of blood glucose concentrations followed by the permanent recurrence of hyperglycemia, thus proving the complete removal of the transplanted cells. Cultured fibroblasts were thus proven capable of supplying sufficient proinsulin to lower the blood glucose concentrations in diabetic animals. The immunological safety system with a combination of artificial expression of cell surface antigen and the administration of the specific monoclonal antibody was an effective safety system for somatic gene therapy.
Diabetes 1992 Aug
PMID:Somatic gene therapy for diabetes with an immunological safety system for complete removal of transplanted cells. 162 70

This study used 10-nm gold particles with 5-7 insulin molecules attached (Au10-Ins) to investigate the site of interaction of insulin with the nuclear envelope during insulin uptake into intact isolated nuclei. Despite its size, and in the absence of ATP, Au10-Ins entered nuclei through the nuclear pore and associated with the heterochromatin. Because Au10-Ins is essentially gold-bovine serum albumin (Au-BSA) with a few insulin molecules attached, the effect of insulin and other growth factors on the nuclear accumulation of BSA coupled to 10-, 15-, and 24-nm-diam colloidal gold particles (Au10-BSA, Au15-BSA, and Au24-BSA) was determined. The Au-BSA complexes were excluded from nuclei in the absence of insulin. Insulin (0.5-100 ng/ml) caused a dose-dependent accumulation of Au10-BSA in the nucleus. The nuclear membrane was shown to be intact by several criteria, therefore, accumulation of Au-BSA occurred via the nuclear pore and was not due to leakage across or through the membrane. Uptake of 15- and 24-nm Au-BSA molecules was not affected by insulin, suggesting the hormone had a limited effect in increasing the functional diameter of the nuclear pores. Glucagon, epidermal growth factor, platelet-derived growth factor, insulinlike growth factor I, and insulin A or B chains did not stimulate the accumulation of Au10-BSA. The insulin-stimulated accumulation of Au10-BSA was blocked by concanavalin A, mimicked by wheat-germ agglutinin, and did not require ATP. The Au10-BSA in the nucleus was associated with heterochromatin, suggesting it bound to a nuclear element.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1992 Feb
PMID:Insulin stimulates accumulation and efflux of macromolecules in isolated nuclei from H35 hepatoma cells. 173 9

It is well established that insulin-dependent diabetes (IDDM) is an autoimmune disease with a strong genetic link to the HLA locus. It is less well understood, however, how the destruction of the insulin-producing beta cells is effected and why neighboring non-beta islet cells are spared. Also incompletely explained are the observations that, unlike other autoimmune diseases such as multiple sclerosis, IDDM does not preferentially affect females, the incidence of the disease is highest among young adults, and there are temporal correlations between the onset of the disease and emotional trauma. We have addressed some of these questions by using transgenic mice that constitutively express the MHC class I antigen Dd in the beta cells of the pancreas. Although both male and female Ins.Dd mice expressed equivalent amounts of the Dd protein only the males developed diabetes. The diabetes in the males could be reversed by castration, and the normoglycemic females became diabetic following either ovariectomy and the implantation of a slow-release pellet containing testosterone or the inclusion of dexamethasone in the drinking water. In contrast, transgenic mice that expressed the herpes simplex virus type 1 glycoprotein D in the pancreatic beta cells were normoglycemic and showed no obvious histopathological consequences. The observation that the beta-cell dysfunction by the increased expression of the MHC class I protein Dd cannot be induced by the herpes viral protein suggests that the cellular damage is related to a specific structure or function of the MHC proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Male-specific beta-cell dysfunction and diabetes resulting from increased expression of a syngeneic MHC class I protein in the pancreata of transgenic mice. 196 48

Antibodies to insulin appear prior to the development of Type I diabetes and their concentration may correlate with the rate of autoimmune beta cell destruction. In order to study potential mechanisms involved in the production of antibodies to insulin, we transplanted different strains of mice with histoincompatible non-islet cells (AtT20-Ins and NIH-3T3-Ins) synthesizing homologous insulin, in contrast to immunization with non-transfected cells and insulin in Freund's adjuvant. The pituitary cell line (AtT20) and the fibroblast cell line (NIH-3T3) were transfected with the rat insulin-II gene (which encodes an insulin molecule identical to that of mouse insulin-II). No antibodies to insulin were found after subcutaneous injection of AtT20-control cells (without the integrated rat insulin gene) or after injection of rat insulin complete Freund's adjuvant. After subcutaneous injections of living AtT20-Ins or NIH-3T3-Ins cells producing insulin (40 to 60 ng insulin/10(6) cells per injection) in two strains (BALB/cJ, C3H/HeJ) but not in a third (SJL/J), antibodies to insulin rapidly appeared. In addition, when AtT20-Ins cells were transplanted into Wistar-Furth rats, insulin antibodies appeared in three out of four animals. The level of antibodies induced was similar to the concentrations of insulin antibodies of prediabetic NOD mice. This finding suggests that during the immune destruction of a cell synthesizing insulin, humoral 'tolerance' to insulin can be rapidly abrogated. Genetic control of this response is suggested by the difference between response of BALB/cJ and C3H/He vs SJL/J.
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PMID:Production of insulin antibodies by mice rejecting insulin transfected cells. 266 99

Because fasting nerve myo-inositol (myo-Ins) is not decreased in patients with diabetes treated conventionally, in whom neuropathy may develop or may have already developed, it seems unlikely that myo-Ins is the metabolic abnormality that initiates diabetic neuropathy, if nerve myo-Ins is not spuriously high during fasting. At 6 weeks after induction of diabetes with streptozotocin in Sprague-Dawley rats we found that endoneurial glucose, sorbitol, and fructose were substantially increased and myo-Ins was decreased, as reported by others. By use of multiple linear regression to assess the effect of disease condition, time after feeding (1.5, 4, and 20 hours), and duration of diabetes (1,2,6 and 12 weeks) on nerve sugars and alcohol sugars, for nerve glucose, sorbitol, and fructose only disease condition was statistically significant factor. For nerve myo-Ins, disease group (control or diabetic rats) (P = 0.08), duration of diabetes (P = 0.02), time after feeding (P less than 0.001), duration x time (P = 0.01), group x duration (P = 0.03), and group x time (P = 0.05) were significant variables. Because nerve myo-Ins was lower at 20 hours than at 1.5 or 4 hours after feeding for all durations of diabetes, one can infer that in human nerve the lowest nerve myo-Ins, not high values, occur in the fasting state. Therefore, one would not expect to find lower nerve myo-Ins levels in human diabetics at times other than the fasting condition.
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PMID:Nerve glucose, sorbitol, fructose, and myo-inositol at various time after feeding in streptozotocin-induced diabetes in rats. 279

Diabetes was induced in rats by administration of streptozotocin. Diabetes occurred within 24 h after treatment. Two forms of diabetes were studied, an acute form (4 days) and a chronic form (2 months). In a separate experiment the effect of insulin and an aldose reductase inhibitor on acute diabetes was studied. Phosphoinositide labelling was done in biopsies of heart with [3H] myo-inositol. It was shown that the incorporation of myo-inositol amounted to about 65% in acute diabetes and 80% in chronic diabetes compared to age-matched controls. The incorporation both in atria and ventricles was affected in a similar way. Muscarinic receptor-mediated phosphatidylinositol breakdown and release of myo-Ins-1 P (myo-inositol 1-phosphate) was unaffected in diabetic hearts in the chronic model. In hearts of diabetic ketotic animals uncoupling of the muscarinic receptor from the phosphoinositide metabolism was apparent. Calcium net influx was significantly reduced in both acute and chronic diabetes compared to age-matched controls. Insulin supplementation to acute diabetic animals significantly improved phosphoinositide labelling with [3H] myo-inositol. No improvement was seen in calcium transport. An aldose reductase inhibitor also facilitated phosphoinositide labelling without improving calcium transport. It is suggested that phosphoinositide metabolism and calcium entry through the slow inward current are independent of one another and the former is sensitive to insulin. It is suggested that insulin by regulating the pool of phosphoinositides and release of endogenous calcium may modulate cardiac function.
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PMID:The effect of diabetes on phosphatidylinositol turnover and calcium influx in myocardium. 316 80

Purified carrier-free 125I-Tyr insulin (125I-Tyr Ins) was injected into the vitelline vein of rat fetuses in utero after 17, 19, or 21 days of gestation. Three minutes later, a radioactivity concentration index (RCI) was calculated by dividing the specific activity of each organ by that of the feto-placental unit. The highest RCI were found in the liver (4.09, 5.97, and 6.48, respectively after 17, 19, and 21 days of gestation). Binding of 125I-Tyr Ins to the liver was inhibited by coinjection of excess unlabeled insulin. Sequential injections of 125I-Tyr Ins followed by excess unlabeled insulin demonstrated that 125I-Tyr Ins binding to the liver was but partly reversible and allowed us to calculate that the half-life of the tracer in the whole body receptor compartment was 6 min in 21-day postcoitum fetuses. After extraction and chromatographic analysis, liver radioactivity appeared composed of undamaged 125I-Tyr Ins and low mol. wt. degradation products (125I- and 125I-tyrosine). Liver maturation was characterized by an enhanced capacity to degrade 125I-Tyr Ins and to expel low mol. wt. radioactive products out of the cells. Autoradiographic studies demonstrated that 125I-Tyr Ins was bound in a saturable manner to the hepatocytes and, to a lesser extent, to the liver hematopoietic cells. Three minutes after the tracer alone, silver grains were predominantly associated with the hepatocytes' plasma membranes. Later, the percentage of internalized grains increased. Because the percentage of liver radioactivity identified as low mol. wt. radioactive products was always smaller than that of internalized silver grains, true 125I-Tyr Ins was actually internalized in the hepatocytes. The rate of 125I-Tyr Ins translocation from the membrane into the cytoplasm increased with the degree of liver maturity. It is concluded that during the last 5 days of gestation, liver maturation concerns insulin internalization and degradation, i.e., postreceptor steps rather than receptor ontogenesis.
Diabetes 1982 Jan
PMID:Maturation of liver handling of insulin in the rat fetus. 675 14

Autoimmune (type 1) diabetes mellitus in mouse, rat, and humans shares several features, including T lymphocyte infiltration into pancreatic islets and a dependence on permissive class II major histocompatibility complex (MHC) alleles. We report here on an experimental model involving mice that express influenza hemagglutinin (HA) under the control of the insulin promoter and, at the same time, a transgenic class II MHC-restricted T cell receptor (TcR) specific for an HA peptide. These mice spontaneously develop islet infiltrates resembling those found in NOD mice and most animals become diabetic within 8 weeks of age. Because of the availability of a clonotypic TcR antibody, we can be confident that the Ins-HA transgene does not induce any measurable alterations in the vast majority of T cells with the transgenic TcR in primary and secondary lymphoid organs. Continuous export of large numbers of HA-specific lymphocytes from the thymus was not required for the manifestation of the disease since mice thymectomized at 3 days after birth still developed the disease albeit with smaller infiltrates.
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PMID:On the various manifestations of spontaneous autoimmune diabetes in rodent models. 752 72

Histological techniques were used to identify antigen-presenting cells (APC) in adoptively transferred diabetes in NOD mice and Ins-HA transgenic mice, and in spontaneously diabetic NOD mice. In adoptively transferred disease, CD4+ T cells and F4/80+ macrophages dominated early infiltrates. By contrast, in spontaneously developing diabetes in NOD mice, lymphocytic infiltrates appeared to be well organized around a network of VCAM-1+ NLDC-145+ ICAM-1+ dendritic cells. Thus, the primary APC spontaneous autoimmune disease appears to be the strongly stimulatory dendritic cell rather than the normally resident macrophage. Next, we used chimeric animals to demonstrate that insulitis and diabetes could occur even when responding T cells were unable to recognize islet-specific antigen directly on beta cells. Altogether, the results demonstrate that immune-mediated damage does not require direct contact between CD4+ T cells and beta cells. Moreover, despite the induction of ICAM-1, VCAM-1, and class II on vascular endothelium near islet infiltrates, these experiments show that recruitment of lymphocytes occurs even when antigen presentation is not possible on vascular endothelium.
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PMID:Antigen-presenting cells in adoptively transferred and spontaneous autoimmune diabetes. 768 60

IL-10 inhibits macrophage-dependent antigen presentation, cytokine production, and generation of allospecific cells in vitro. These findings have lead to the widespread expectation that IL-10 may be a useful immunosuppressive agent to inhibit allograft rejection or autoimmunity in vivo. We used two experimental paradigms to study effects of murine IL-10 on in vivo immune responses. First, fetal pancreata or adult pancreatic islets from transgenic mice expressing IL-10 in pancreatic beta cells (Ins-IL-10 mice) were grafted across the MHC barrier to examine if IL-10 could inhibit allograft rejection. Second, Ins-IL-10 mice were crossed with transgenic mice expressing lymphocytic choriomeningitis virus (LCMV) antigens in pancreatic beta cells. These mice were infected with LCMV to elicit autoimmune diabetes, allowing us to ask if IL-10 protects islets from autoimmune destruction. We observed that allografts from IL-10-transgenic donors were rejected with comparable kinetics to the rejection of control nontransgenic allografts, indicating that IL-10 does not inhibit allograft rejection. After LCMV infection, IL-10 and LCMV antigen double transgenic mice developed diabetes earlier than LCMV antigen single transgenic littermates, suggesting that IL-10 does not inhibit islet antigen presentation or recognition. Our results contrast to in vitro observations and suggest that IL-10 cannot overcome immune-mediated tissue destruction within the pancreas.
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PMID:Pancreatic islet production of murine interleukin-10 does not inhibit immune-mediated tissue destruction. 813 75


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