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Biomedical subjects

B Ziegler

Publications and source records attributed to B Ziegler.

At least 91 records · Page 5Linked to original sources
PubMed1988

Genetic control of susceptibility to severe hyperglycaemia evoked by CFA/SZ-induced immune response against beta cells in various rat strains.

A novel approach has previously been reported to induce an insulin-dependent (type 1) diabetes mellitus in Wistar and Lewis rats by subdiabetogenic dose of the beta cell toxic agent streptozotocin injected i.p. 24 h after a polyclonal activator of lymphocytes, the complete Freund's adjuvant, was administered. The results from a comparative study in Wistar rats and congenic Lewis rats of the haplotype RT1a and RT1u demonstrate that both the genetic background and genes linked to the major histocompatibility complex are probably involved in the genetic control of susceptibility to the induction of hyperglycaemia in this experimental diabetes model. The susceptibility to hyperglycaemia was strongly associated to the non-specific activation of the immune system by administration of complete Freund's adjuvant only. From these data it is suggested that the genetic control of diabetes induction in this animal model is caused by genetic control of the immune/autoimmune reactivity involved in the mechanisms of beta cell destruction.

Animals↗
PubMed1988

[Production and use of monoclonal glucagon and insulin antibodies--reduction of pancreatic insulin in rats by treatment with complete Freund's adjuvant].

Murine monoclonal antibodies against glucagon and insulin were generated by somatic cell hybridization and partially characterized. The monoclonal glucagon antibody K79bB10 exhibited no cross-reaction with gut glucagon. This antibody and the insulin antibody K36aC10 were found of very high concentration in ascites. An ascites dilution of 1:5,000 was used for immunohistochemical staining of insulin and glucagon on Bouin-fixed pancreatic tissue sections. By indirect immunofluorescence technique we could demonstrate a reduction of pancreatic insulin in Lewis rats after treatment with complete Freund's adjuvant. The glucagon staining was not altered. The results were confirmed by radioimmunoassay analysis of pancreatic insulin and glucagon content.

Animals↗
PubMed1987

Biochemical, immunohistochemical and ultrastructural studies of the alteration of pancreatic beta cells resulting from the combined effects of complete Freund's adjuvant and non-diabetogenic doses of streptozotocin.

Injection of complete Freund's adjuvant (CFA) 24 h prior to treatment of rats with non-diabetogenic doses of streptozotocin (STZ) produced a reduction in pancreatic insulin content associated with ultrastructural changes and a decrease of the volume density of insulin-immunoreactive cells without affecting other islet cells. After one injection of CFA and STZ, pancreatic insulin content was decreased by 69% (p less than 0.01) within 48-96 h, while plasma glucose concentrations were not changed. The volume density of beta cells in pancreata of these rats was reduced by 40% (p less than 0.01) compared with citrate-saline treated control rats. No significant lymphocytic infiltration was detectable in islets, but the exocrine pancreas exhibited inflammatory lesions. Degranulation and vacuolation was evident by ultrastructural analysis. Following administration of CFA or STZ alone, pancreatic insulin content was insignificantly reduced, and major histopathological changes in pancreatic islets were apparently absent. These results support the hypothesis that activation of the immune system by CFA allows an anti-beta cell reaction to develop following exposure to the beta cell toxic agent STZ.

Animals↗
PubMed1987

Genetic control of diabetes induction by complete Freund's adjuvant combined with subdiabetogenic doses of streptozotocin in Lewis rats--evidence for transient cytotoxicity against beta cells.

The non-specific activation of the immune system by administration of complete Freund's adjuvant (CFA) was examined in two congenic Lewis rat strains LEW. 1A (RT1a) and LEW. 1W (RT1u) as a possible mean of amplification of the specific immune response, directed to pancreatic beta cells induced by multiple non-diabetogenic injections of streptozotocin (STZ). Rats were given intraperitoneally 0.5 ml CFA and 1 day later 25 mg/kg body weight STZ. This combined treatment was repeated twice at weekly intervals. Control groups received vehicle, STZ or CFA only with the same doses and at the same times. Only CFA/STZ-treated rats developed a persisting hyperglycaemia (greater than 15 mmol/l glucose) namely 3/18 (17%) LEW. 1W and 47/76 (62%) LEW. 1A rats. The pancreatic insulin content in these hyperglycaemic rats was reduced by 96.6% in LEW. 1A rats and by 93% in LEW. 1W rats measured 8 weeks after the last CFA/STZ treatment. The response to CFA indicated by an increase of number of peripheral leucocytes and relative spleen weight gain at 7 days after CFA administration, was higher in LEW. 1A rats compared with those of LEW. 1W rats. Spleen cells harvested 72 h/48 h after the first and second CFA/STZ administration showed a cytotoxic reaction to isolated syngeneic islets as measured by 51Cr-release in vitro. Control rats receiving vehicle, STZ or CFA only showed no cellular anti-islet cytotoxicity. The anti-islet cytotoxicity of spleen cells was only transient and disappeared after the third CFA/STZ administration. Anti-islet cytotoxic antibodies were not detectable in this short-term study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Generation and partial characterization of monoclonal antibodies reactive with islet cell antigens.

Islet cell antibodies have been detected in more than 60% of newly diagnosed type I diabetics. Their pathogenetic role is still unclear. We have generated monoclonal antibodies (mc-ab) reactive with islet cell antigens by fusing mouse myeloma cells with spleen cells from Balb/c mice immunized with pancreatic islet cells. Hybridomas producing islet cell surface antibodies (ICSA) were detected by indirect immunofluorescence on viable cells from rat islets or rat insulinoma. Cytoplasmic islet cell antibodies (ICA) were detected by indirect immunofluorescence on Bouin-fixed sections of mouse pancreas. The ICSA- and/or ICA-producing hybridomas were cloned twice by limiting dilution. This paper describes six different mc-ab. All hybrid cell lines obtained produced IgM antibodies. Four of them mediate complement-dependent cytotoxicity to viable rat islet cells. In the present study the heterogeneity of circulating ICSA is demonstrated. Also, a monoclonal beta cell surface autoantibody K56aF3 was produced by fusion of spleen cells from a mouse treated with sub-diabetogenic doses of streptozotocin in combination with complete Freund's adjuvant. It was cytotoxic against islet cells up to a dilution of 1:1,000 and it could inhibit the insulin secretion from neonatal rat islets cultured in RPMI 1640 as stimulated by glucose or by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine common with glucose. The latter effect was reversible as indicated by the recovery of insulin secretion in a subsequent culture period without mc-ab. These results suggest that circulating ICSA in type I diabetics may alter beta cell function and thereby contribute to the pathogenesis of type I diabetes.

Animals↗
PubMed1987

Intracoronary streptokinase versus intravenous anisoylated plasminogen streptokinase activator complex in the treatment of acute myocardial infarction.

As part of a randomised multicentre study, 16 patients with acute myocardial infarction were treated with either anisoylated plasminogen streptokinase activator complex (APSAC) administered as an intravenous bolus of 30U or 250,000U of streptokinase by the intracoronary route. The reperfusion was documented angiographically during a 90-minute period and possible reocclusion was assessed at 90 minutes and 24 hours after the start of therapy. The percentage of reperfusion obtained in the APSAC group was 83% versus 63% in the streptokinase group. One reocclusion was seen after 24 hours in the APSAC group. Fibrinolytic activity was more pronounced in the APSAC group but there were no major bleeding problems in either group. The administration of 30U of APSAC by an intravenous bolus injection produced results at least as good as those obtained with intracoronary streptokinase and in addition offered the advantage of a simpler and quicker administration.

Adult↗
PubMed1987

Destruction of pancreatic beta cells in rats by complete Freund's adjuvant combined with non-diabetogenic doses of streptozotocin.

Non-specific activation of the immune system by complete Freund's adjuvant (CFA) in combination with non-diabetogenic doses of streptozotocin (STZ) was used to study autoimmune reactions against pancreatic islets. Male Lewis RT1a rats received either CFA (0.5 ml/kg) 24 hr prior to the injection of STZ (25 mg/kg), or CFA or STZ alone. The injections of CFA followed by STZ, but not CFA or STZ alone, produced a 69% (p less than 0.01) reduction in pancreatic insulin content associated with necrosis and a decrease of the relative volume density of insulin-immunoreactive cells without affecting other islet cells. Two injections of CFA and STZ induced hyperglycemia. This was associated with a depletion of pancreatic insulin and a significant reduction in the relative volume density of insulin-immunoreactive cells (p less than 0.01) and in the mean islet area (p less than 0.01). On day 20, after treatment with 3 injections of CFA and STZ, the animals developed persistent hyperglycemia. The pancreata in these rats contained less than 12% B-cells, and the insulin content was reduced by 96% (p less than 0.01). The main components of the remaining atrophic islets were glucagon- and somatostatin-immunoreactive cells. No significant lymphocytic infiltration into the islets was detectable, but the exocrine parenchyma exhibited severe inflammatory lesions. Degranulation and vacuolation of B-cells was evident by ultra-structural analysis. The volume densities of insulin containing cells and islet area were not changed after 3 injections of either CFA or STZ alone, although the pancreatic insulin content decreased by 61% (p less than 0.01) and 39% (p less than 0.05), respectively. These treatments did not produce an increase in plasma glucose. The present results demonstrate that CFA in combination with non-diabetogenic doses of the beta cytotoxic agent STZ induces B-cell destruction without significant insulitis. Our observations support the hypothesis that activation of the immune system by CFA allows an anti-B-cell immune reaction to develop following exposure to STZ.

Animals↗
PubMed1987

[Optimal production of murine monoclonal antibodies in ascites of syngeneic mice by a single whole body irradiation].

Hybridoma cells injected intraperitoneally into mice induce formation of ascites tumors producing ascites fluid with high levels of monoclonal antibodies. Several parameters affect the growth of the immunoglobulin-producing tumors in vivo. In the present study the average ascites tumor formation rate of 10 different hybridomas could be increased from 32% (n = 338 mice) to 77% (n = 112 mice) by only one whole body irradiation of paraffin-pretreated-Balb/c mice. Production of monoclonal antibodies was better in males because significantly (p less than 0.01) increased volume of ascites fluid. From the increased tumor formation rate in irradiated mice it is suggested that in non-irradiated recipients the tumor growth rate was lowered by immunological reactions against hybridoma cells provoked by cell surface neoantigens revealed by cell fusion and/or tumor-associated antigens of the myeloma parent cells as well as by altered antigen pattern caused by possible mutations in the myeloma cell line and/or Balb/c/K strain.

Animals↗
PubMed1987

Cytotoxic activity of sera from diabetic BB rats against BB rat islet--a functional study.

[3H] leucine incorporation into islet proteins, insulin secretion, hormone content (insulin, glucagon) and DNA synthesis were measured in cultured BB rat islets in a study to compare the effect of freshly prepared BB rat serum obtained from non-diabetic and newly diagnosed diabetic BB rats on islet functions. After exposure of isolated BB rat islet to a mixture of tissue culture medium and BB rat serum (1:1) for 24 hr, islet lysis was induced by 40% of the diabetic BB rat sera whereas the remaining 60% of diabetic BB rat sera tested did not influence islet functions as evidenced by insulin net production, glucose-induced insulin release and DNA synthesis measured in a subsequent culture period in TCM 199, 10 mmol/l glucose supplemented with 10% neonatal calf serum or short-term incubations. After exposure of islets to sera with anti-islet cytotoxicity the majority of islet cells were destroyed as indicated by a drastically reduced [3H] leucine incorporation into islet proteins and by a diminution of hormone and DNA content of islets. This toxicity against islets was overcome by heat treatment (58 degrees C, 30 min) of sera. The results indicate that heat-labile components in certain diabetic sera of BB rats can lyse the majority of islet cells in BB rat islets within 24 hr. Our assay may help to dissociate humoral and cellular components which cause the injury of beta cells and the onset of diabetes in BB rats.

Animals↗
PubMed1986

Adverse drug reaction reporting system: developing a well-monitored program.

The spontaneous reporting of adverse drug reactions (ADRs) at the St. John's Hospital and Memorial Medical Center was well below that reported in the literature. After review of procedures for reporting of ADRs at these institutions, the authors developed a system that was approved by their joint P & T Committee. The ADR reporting program developed uses concurrent monitoring of most hospital inpatients and a retrospective review of all emergency room patients. In the year after program implementation, 162 ADR reports were documented. From this program, a group of serious ADRs to one agent was identified and reported, both to the Food and Drug Administration and to the manufacturer. A well-developed ADR monitoring program may lead to heightened physician and nurse awareness and early problem identification, possibly decreasing morbidity for hospitalized patients.

Documentation↗
PubMed1986

[Relation between the labeling index and thymidine incorporation in cultured islands of Langerhans of the rat: stimulation of DNA synthesis by EGF-S3].

DNA synthesis and labelling index of isolated neonatal rat islets were investigated during a 4 to 5 culture period in TCM 199 (10 mmol/l glucose) under selected conditions, as change of serum concentration in the medium or addition of a proliferation stimulating fraction. Additionally it should be proved whether the DNA-synthesis of pancreatic islets, measured as [3H]-thymidine incorporation, is representative for the amount of cells during the S-phase (= "growth fraction"). There is a correlation between the incorporation of [3H]-thymidine into the TCA-precipitate and the labelling index of islets determined on HE-stained radioautographs. For this reason and because of being less time-consuming, the measurement of DNA synthesis is a suitable screening method for selection of factors increasing the growth fraction of pancreatic beta-cells. Only the addition of FGF-S3 (growth stimulating raw prepared isolated from bovine brain) during culture caused a significant increase of DNA synthesis and labelling index of the islets. The labelling index of radioautographs stained by immunofluorescence method for insulin did not differ significantly from that determined at HE-stained radioautographs. Insulin secretion and content of the islets were not influenced by the addition of FGF-S3.

Animals↗
PubMed1985

Pregnancy-associated changes in the endocrine pancreas of normoglycaemic streptozotocin-treated Wistar rats.

The effect of pregnancy on pancreatic insulin content and relative B-cell volume has been studied in normoglycaemic Wistar rats treated with streptozotocin 14 days before mating. A single intravenous injection of streptozotocin (30 mg/kg body weight) caused a significant reduction of pancreatic insulin content and B-cell volume. The islet insulin content was 60% of control values. However, pregnancy-associated adaptation was preserved in these streptozotocin-treated animals. Plasma insulin levels, pancreatic insulin and B-cell volume were significantly enhanced compared with non-pregnant rats investigated on the same date. The incorporation of [3H]-thymidine into islets from pregnant rats (day 10.5) was higher than that in islets isolated from non-pregnant animals. After delivery insulin content and B-cell volume returned to pre-pregnant values. Also during a longer period after streptozotocin treatment (156 days), no measurable enhancement of B-cell volume and pancreatic insulin content was observed indicating the unresponsiveness of residual B cells to compensate spontaneously for the loss despite persisting normoglycaemia.

Animals↗
PubMed1985

Inhibition of glucagon release of isolated islets of Langerhans by monoclonal antibodies.

The presence of islet cell cytoplasmic antibodies (ICA) and islet cell surface antibodies (ICSA) at the time of diagnosis of type 1 (insulin-dependent) diabetes mellitus has been taken as evidence that autoimmune mechanisms are involved in the pathogenesis of the disease. The demonstration that ICSA in the presence of complement are preferentially lytic for beta-cells may be important in defining the role of these autoantibodies in the pathogenesis of type 1 diabetes. Because of the polyclonality of the immune response, the ICA and ICSA molecules of diabetic patient vary enormously in their binding parameters. For this reason we have generated monoclonal antibodies (MC-Ab) to islet cell antigens. In this study we investigate the effect of the two MC-Ab K28 A1 and K28 D6 resulted from the same fusion of the P3-X63-Ag8 murine myeloma cell line with the spleen cells of a Balb/c mouse immunized with rat islet cells on the hormone release of isolated rat islet in co-culture with the antibody-secreting hybridomas. The MC-Ab K28 D6 binds to both islet cell cytoplasmic and surface antigens, the K28 A1 is only reactive with cytoplasmic antigens. Surprisingly, in contrast to the monoclonal antibody K28 A1, K28 D6 enhanced the glucagon content and diminished the insulin secretion of the islets. Either the K28 D6 is directed to an epitope occurring on the beta- as well as alpha-cells or the antibody-mediated inhibition of the glucagon release results in a significantly reduced insulin secretion.

Animals↗