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Biomedical subjects

B Ziegler

Publications and source records attributed to B Ziegler.

At least 73 records · Page 4Linked to original sources
PubMed1989

Augmentation of streptozotocin-induced hyperglycemia in mice by prior treatment with complete Freund's adjuvant.

The effect of complete Freund's adjuvant (CFA), in combination with streptozotocin (STZ), on pancreatic insulin content, plasma glucose, and pancreatic histopathology were studied in male Balb/c mice. One injection of CFA, followed 24 h later by a single dose of 100 mg/kg of STZ (group I), produced a 92% (p less than 0.01) reduction in pancreatic insulin, a 54% (p less than 0.01) increase in glucagon content, and severe hyperglycemia. The depletion of pancreatic insulin was associated with degranulation, necrosis of beta cells, and reduction of the apparent islet size. Focal pancreatitis, without apparent islet inflammation, occurred in all animals in this group. After treatment with STZ alone (group II), pancreatic insulin content decreased 73% (p less than 0.01), whereas plasma glucose levels, even though being in the hyperglycemic range, were significantly lower (p less than 0.02) than the mice in group I. Although pyknotic and hypertrophic cell nuclei could be observed in several islets of mice from group II, major histopathological changes, such as pancreatitis and extensive beta cell necrosis seen in group I, were absent. The results show that in the Balb/c mouse strain, a nonspecific insult by CFA prior to a cell-specific cytotoxic insult markedly enhanced destruction of beta cells and the development of hyperglycemia.

Animals↗
PubMed1989

Detection of islet cell specificity of monoclonal islet cell surface antibodies by means of double-staining immunofluorescence.

We have generated monoclonal antibodies (mcab) reactive with islet cell surface antigens. 10 different mcab were characterized regarding their islet cell binding specificity by means of a modified double immunofluorescence test. At this assay, the monoclonal islet cell surface antibodies were visualized on rat islet cells by indirect immunofluorescence with fluorescein isothiocyanate-labelled antibodies against mouse immunoglobulin. The alpha and beta cell specificity was determined by indirect immunofluorescence using anti-glucagon or anti-insulin serum and a tetramethyl rhodamine isothiocyanate-labelled second antibody. The target islet cell suspension used contained 61% beta and 23% alpha cells. The monoclonal antibody K28D6 preferentially reacted with alpha cells. The binding of K29aC6 and K56aF3 indicates a high specificity against beta cells. The remaining 7 antibodies were reactive with alpha as well as with beta cells.

Animals↗
PubMed1989

Early enhanced beta cell replication in normoglycaemic Wistar rats in response to a subdiabetogenic dose of streptozotocin.

The effect of a single subdiabetogenic dose of streptozotocin (30 mg/kg body weight) on pancreatic insulin content and relative beta cell volume has been studied in normoglycaemic Wistar rats treated with streptozotocin either 2, 3 or 14 days after STZ was given. A single intravenous injection of streptozotocin caused a significant reduction of pancreatic insulin content, islet and beta cell volume, accompanied by a significantly diminished islet insulin content. The glucose- and 3-isobutyl-1-methylxanthine-stimulated insulin secretion was significantly lower in islets obtained 2 or 3 days after streptozotocin injection compared with those of vehicle-treated controls. 14 days after streptozotocin injection, beta cell volume and pancreatic insulin content partially recovered. At this time islet insulin content and secretory responsiveness were enhanced compared to the early phase following streptozotocin administration. The incorporation of [3H] thymidine into islet DNA was significantly enhanced at day 2 or 3 after streptozotocin application, whereas at day 14 the DNA synthesis corresponded to values from control rats. Despite persisting normoglycaemia, the beta cell volume of streptozotocin-treated rats was only 52% vs. control values, thus indicating the unresponsiveness of residual beta cells to compensate spontaneously for the beta cell loss.

Animals↗
PubMed1989

Heterogeneity of monoclonal antibodies against pancreatic beta cells.

Sixteen murine hybridoma-secreting monoclonal antibodies against pancreatic islet cell surface antigens (mc-ICSA) have been produced by the cell fusion technique using splenocytes from xenogeneic islet cell- or RIN cell-immunized Balb/c mice. In addition, some mice were autoimmunized by subdiabetogenic doses of the beta cell toxin streptozotocin in combination with complete Freund's adjuvant. Isotyping of the mc-ICSA revealed that 13 of the antibodies belong to the class IgM, and 3 to the subclass IgG1. The specificity of these mc-ICSA has been detected by means of the indirect immunofluorescent technique using primary rat islet cells suspensions, following a procedure of double immunostaining for pancreatic insulin and glucagon. Furthermore, the cross reactivity of these mc-ICSA was studied using endothelial, neuroblastoma and fibroblast cell lines and primary rat splenocytes. One out of the 10 mc-ICSA tested was alpha cell-specific, 2 were beta cell-specific and 7 out of 10 were reactive with both alpha and beta cells. Eleven mc-ICSA showed no cross-reactivity with the 5 other cell types tested. The binding of one mc-ICSA was blocked by 6 of the ICSA-positive human sera which were tested, suggesting that this monoclonal recognizes the same antigenic determinant. The same mc-ICSA diminished the glucose- and arginine-stimulated insulin secretion of isolated rat islets.

Animals↗
PubMed1989

Monoclonal islet cell surface antibody dependent cellular cytotoxicity mediated by rat splenocytes with the RIN cell line as target.

A new method is described for testing monoclonal islet cell surface antibodies for their ability to mediate cellular immune effector mechanisms (ADCC). For the first time an IgM mediated cellular cytotoxicity is demonstrated. By using the RIN cell line as target the method was reproducible and easy to perform. The significance of such definition of monoclonal ICSA's to experimental diabetes research is discussed.

Animals↗
PubMed1989

Immunological disorders of type 1 diabetes mellitus.

The specific genes causing type 1 diabetes susceptibility in any species are unknown. Serological HLA studies have shown susceptibility to type 1 diabetes is linked to HLA DR3 and DR4 allels, whereas DR2 and DR5 alleles contain protective elements. DR4 chromosomes can be divided into diabetes prone or resistant by restriction fragment length polymorphism analyses with cDNA probes for DQ beta-gene. No type 1 diabetes-specific environmental factors have been revealed to be convincingly implicated in human type 1 diabetes. Congenital rubella, by its lasting influence on T cells creates susceptibility to many organ-specific autoimmune diseases. Certain dietary proteins shown in BB rats as well as hyperglycemia during the prenatal period increase the later incidence of type 1 diabetes. Human type 1 diabetes results from a progressive probably autoimmune loss of the pancreatic beta cells. The immunologic hallmarks of type 1 diabetes is the lymphocytic infiltration of pancreatic islets, the hyperexpression of class I MHC on all islet cells and the abarrent class II MHC expression on beta cells within inflamed islets, the increased frequency of activated T cells in islet and circulation. It is generally accepted that cellular immunity plays the major role in the pathogenesis of type 1 diabetes. The heightened autoimmune reactivity being detectable during the preclinical period, lasting months to years, has been proved by antibodies directed against cytoplasmic islet cell antigens (ICA), beta cell surface antigens (ICSA), insulin (IAA), and with a lower frequency against non-islet cell antigens. The presence of IgG insulin autoantibodies and complement fixing ICA confers increased risk for future type 1 diabetes development in genetically predisposed individuals than the presence of either marker alone. For ICSA a more specific and quantitative assay is needed. 90% of children developing type 1 diabetes were detected positive for ICA and/or IAA. By the time of clinical onset if type 1 diabetes some 90% of the insulin secretory beta cell mass has already been destroyed. For this reason, new approaches are needed to address the causes of diabetes and not just the consequences. The development of insulin-dependent diabetes may be reversible, or even preventable by early detection coupled with the judicious use of immunotherapy.

Animals↗
PubMed1989

[Metabolic changes and infusion therapy in ileus].

The aim of the investigation was to determine the changes in intermediary metabolism that occur in cases of ileus, and to develop a concept for parenteral perioperative nutrition on a pathophysiological basis. Seventeen metabolically healthy patients, suffering from mechanical ileus, have been evaluated. Besides the nonspecific metabolic changes characteristic of the postaggressive metabolism (abnormalities in peripheral glucose utilization, gluconeogenesis, lipolysis, proteolysis) we were able to demonstrate elevated serum levels of albumin, lactate and arachidonic acid preoperatively in these patients. The plasma histamine levels lay within normal limits. In the immediate postoperative phase (i.e. from 1.-3. postoperative day) we found a marked reduction in the serum levels of glucoplastic amino acids (about 30%), albumin (40%), pre-albumin (80%) and cholesterol (50%). We therefore suggest that, apart from electrolyte solutions, patients with an ileus should receive fructose (1600 kcal/day) preoperatively and from the first postoperative day amino acids (1 g/kg of body weight) and human albumin (as required) should be administered in addition.

Amino Acids↗
PubMed1989

Streptozotocin-diabetic BB/OK rats accept permanently BB/OK-islet grafts without immunosuppression.

The recurrence of hyperglycaemia after transplantation of BB rat islets in partially inbred BB rats with an autoimmune diabetes could be either caused by graft rejection or by autoimmune destruction. We investigated in the BB/OK rat substrain which does accept BB/OK rat skin grafts permanently, the survival of BB/OK islet grafts by using streptozotocin-diabetic BB/OK rats as recipients. We observed a permanent acceptance of islet grafts despite using animals inbred for only 8 generations. The results demonstrated homogeneity for islet grafts and provide evidence that an autoimmune B-cell destruction cannot be triggered by a direct (toxic effect on immune cells) or indirect (due to B-cell killing) action of a single large doses of streptozotocin in BB/OK rats.

Animals↗
PubMed1989

Purification of mouse monoclonal antibodies by chromatography on sepharose 6 B.

By using Sepharose 6 B, a simple procedure for purification of mouse monoclonal antibodies (mcAbs) of the IgM and IgG class from ascites has been developed. The procedure which was applied to purify mcAbs against insulin and pancreatic islet cells permits either direct chromatographic separation from ascites protein components or after precipitating the immunoglobulins with ammonium sulphate. Recovery of the immunoglobulins was found to be approximately 80%, and the immunological reactivity, as tested by indirect immunofluorescence and ligand binding assay, was almost completely retained. For purification of IgG from ascites, precipitation with ammonium sulphate is recommended prior to chromatography on Sepharose 6 B, whereas IgM can directly be subjected without any pretreatment.

Animals↗
PubMed1989

Determination of islet cell surface antibodies in first-degree relatives of type 1 diabetic patients using rat insulinoma cells.

Titre of islet cell surface antibodies (ICSA) in 114 sera from healthy control probands and 177 sera from first-degree relatives of Type 1 diabetic patients was determined by indirect immunofluorescence using rat insulinoma (RIN) cells as target. All sera were tested at four dilutions (1/40-1/320). 10(5) RIN cells were incubated with 100 microliters diluted serum overnight at 4 degrees C followed by a 45 min-incubation with a FITC-labelled goat anti-human globulin. Titre curves were calculated by double logarithmic regression. ICSA titre was defined as the serum dilution producing cell surface fluorescence on 40% of RIN cells. Based on these data a serum is defined as ICSA positive when the ICSA titre calculated is higher than 1:142, quantil Q (0.97). Twenty-five out of 177 (14%) sera of first-degree relatives of Type 1 diabetes were ICSA positive with a mean titre of 1/393, range 1/145-1/1,740, while 2/114 (1.7%) control sera were weakly positive for ICSA. These data demonstrate the significantly increased ICSA prevalence in first-degree relatives of Type 1 diabetic patients. The present study suggests that RIN cells may represent a useful tool for standardization of ICSA assay.

Adolescent↗
PubMed1989

Immunohistochemical localization of HTLV-I p19- and p24-related antigens in synovial joints of patients with rheumatoid arthritis.

In formalin-fixed, paraffin-embedded synovial tissues from patients with early proliferative rheumatoid arthritis (RA), immunoreactivity could be demonstrated utilizing monoclonal IgG antibodies reactive with the p19 and p24 protein of human T cell leukemia virus (HTLV-I). Additionally, surgical specimens of fresh unfixed synovial tissues from patients with RA also demonstrated immunoreactivity. At the light microscopic level, both HTLV-I antigens were detected in approximately 45% of the rheumatoid synovial tissues by the immunocolloidal gold method with silver enhancement (IGSS) and the avidin-biotin-complex technique (ABC), whereas six of eight of the frozen RA specimens stained positive by immunofluorescence. Patients whose synovial tissues were immunoreactive by immunofluorescence were seronegative to HTLV-I antigens as determined by ELISA and immunoblotting. Conversely, cases with osteoarthritis, juvenile rheumatoid arthritis, psoriatic arthritis, Dupuytren's contracture, and gangrene were shown to be nonreactive by immunohistochemistry. The results indicate that expression of antigens is related to or crossreactive with HTLV-I in synovial tissues from patients with rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1988

Islet beta-cytotoxic monoclonal antibody against glycolipids in experimental diabetes induced by low dose streptozotocin and Freund's adjuvant.

Diabetes was induced in BALB/c mice by four injections of a subdiabetogenic dose (40 mg/kg) of streptozotocin in combination with CFA. The treatment increased the plasma glucose from 5.8 +/- 0.1 to 22.1 +/- 1.3 mmol/liter (n = 9). The diabetic animals had circulating islet cell surface antibodies (75%), and a monoclonal islet cell surface IgM antibody, K56aF3, generated from one of the diabetic BALB/c mice, mediated C-Dependent cytotoxicity against insulin-producing cells and inhibited glucose-stimulated insulin release from isolated rat islets. Solid phase assay on thin layer chromatograms showed no binding of the K56aF3 antibody to glycolipids prepared from relevant cells. However, testing against a series of glycolipids of various non-pancreatic origins showed a preferential binding to a nine-sugar glycolipid isolated from human erythrocytes carrying an unusual blood group A determinant (type 3). It is suggested that this mAb may be associated with the development of diabetes following a combination of polyclonal activation and non-diabetogenic doses of streptozotocin.

Animals↗
PubMed1988

Identification of monoclonal antibodies to pancreatic islet cells by immunoperoxidase staining.

Immunoperoxidase staining and enzyme-linked immunosorbent assay (ELISA) were used to identify monoclonal antibodies that reacted with pancreatic islet cells. All monoclonal antibodies produced against isolated human or rat pancreatic islets including one mouse autoantibody reacted with pancreatic islets in formalin-fixed pancreas sections, but not with rat kidney or thyroid. Reactivity was also found with suspensions of normal rat islet cells and rat insulinoma cells using a 3-stage immunoperoxidase procedure and an ELISA technique. Differences were observed in staining intensity between the various antigenic substrates tested suggesting variable cross-reactivity and/or number of epitopes. The sensitivity of the immunoperoxidase technique proved to be favourable for identification of monoclonal antibodies that recognize cellular constituents such as islet cell antigens present in low concentrations.

Animals↗
PubMed1988

Screening monoclonal islet cell surface antibodies (ICSA) by radioimmunoassay--detection of crossreactivity with ICSA from insulin-dependent (type 1) diabetic patients.

A radioimmunoassay for the detection of monoclonal islet cell antibodies was developed using rat insulinoma cells as antigen carriers and 125I-labeled affinity-chromatographically purified anti-mouse Ig antibodies for detecting cell-bound mouse Ig. Prior to the assay cells had been attached to glass tubes by poly-dimethyl-diallyl ammonium chloride thus allowing to perform the assay as easy as a solid-phase immunoassay. Incubation protocol and cell number were chosen to ensure a high sensitivity of the assay. Results compared well with immunofluorescence findings. Of seven monoclonal islet cell antibodies tested for crossreactivity only one was displaceable by islet cell surface antibodies from diabetic sera. This antibody was induced by immunization with human islets whereas all others were from mice which had been autoimmunized with streptozotocin and complete Freund's adjuvant.

Animals↗