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Biomedical subjects

B Ziegler

Publications and source records attributed to B Ziegler.

At least 37 records · Page 2Linked to original sources
PubMed1994

Antibody response in rats against non-toxic glucose sensor membranes tested in cell culture.

Several glucose sensors have been developed, but none are commercially available. The most urgent in vivo problem is the drift of glucose sensor output with time, which may be caused by leakage or denaturation of glucose oxidase, and events at the body-sensor interface such as protein coating, encapsulation with cells, toxicity of the device and inflammation. In the present study, a specific immune response against the outer cellulose acetate membrane of a glucose sensor implanted into rats has also been proved. The immune response against polymeric membranes can be confirmed by detection of specific immunoglobulin G antibodies to cellulose acetate, polyurethane and regenerated cellulose after implantation of the respective membrane. The individually different antibody formation against polymers in rats was amplified by one application of complete Freund's adjuvant in combination with the first implantation. The cell culture results using the fibroblast cell line L-929 showed only a minor toxicity of regenerated cellulose, whereas the other polymers had no effect on cell growth and viability. From the results of this study, it is proposed to integrate immunogenicity as a further parameter for evaluation of the biocompatibility and biosafety of materials or medical devices which are provided for implantation.

Animals↗
PubMed1994

No association between anti-bovine serum albumin antibodies and islet cell reactive antibodies in newly diagnosed type 1 diabetic patients.

Serological findings have suggested that antibodies (Ab) to bovine serum albumin (BSA-Ab) are associated with type 1 diabetes mellitus. The aim of our study was to evaluate a competitive fluid-phase radioimmunoassay for detecting BSA-Ab using different incubation times and to study a possible association of these BSA-antibodies with autoantibodies (AAb) frequently detected in type 1 diabetic patients. For the overnight incubation time, there was an enormous overlap in the [125I]BSA binding by serum samples between 52 newly diagnosed type 1 diabetic patients (mean [125I]BSA binding 23.6 +/- 17.4%) and 54 healthy blood donors (mean [125I]BSA binding 10.2 +/- 15.7%). By an incubation time of only 3 min the BSA-antibody prevalence was found to be 15.4% (8/52) for type 1 diabetic patients and 3.7% (2/54) for control subjects. However, there was no association between BSA-Ab and type 1 diabetes-associated antibodies as cytoplasmic islet cell antibodies (ICA), or glutamate decarboxylase autoantibodies. Our results confirm that (i) BSA-Ab occur more frequently in newly diagnosed type 1 diabetic patients compared with a healthy control group and (ii) that the BSA-Ab detected by the fluid-phase radioimmunoassay with an incubation time of 3 min are more disease-associated than the [125I]BSA binding after an overnight incubation. The competitive BSA-Ab fluid-phase radioimmunoassay described is a simple and rapid method to detect antibodies specifically reactive with BSA. It is suggested that the humoral immune reactivity to BSA in type 1 diabetic patients probably reflects an unspecific defect of the immune system and gives no additionally diagnostic value about the type 1 diabetes.

Adolescent↗
PubMed1994

Inhalation of resuspended road dust, but not ammonium nitrate, decreases the expression of the pulmonary macrophage Fc receptor.

Pulmonary macrophages (PM) play a key role in the immune defenses of the lung. When stimulated, PM express Fc receptors (FcR) that regulate the immune response. PM were assayed for FcR expression following subchronic inhalation exposure of adult Fischer 344 rats to either 90 micrograms/m3 nitrate (NH4NO3), 300 micrograms/m3 road dust, or clean air, for 4 h/day, 4 days/week, for 8 weeks. PM were lavaged from the lungs and attached to glass coverslips for 18 h. PM FcR were labelled with rat IgG conjugated with cyanine-3. For each exposure, FcR were determined with a Meridian ACAS 570 confocal cytometer by imaging the fluorescence of 50 cells. We found that the IgG binding to FcR (in arbitrary fluorescence units, FU, per cell) for PM from road dust exposed rats was less (835 +/- 39.3 FU/cell) than that for PM from both ammonium nitrate or clean air-exposed rats (1115 +/- 58.0 FU/cell and 1123 +/- 46.6 FU/cell, respectively). While acid incubation conditions in vitro (pH 5.5 for 30 min to simulate the acid environment of ammonium nitrate inhalation) resulted in a 16% decrease in IgG binding (P < 0.05), IgG binding to PM from acid aerosol exposed rats was no different than the IgG bound to PM from clean air-exposed rats. PM exposed to road dust in vivo expressed 25% fewer FcR (P < 0.05). Three-dimensional images of PM failed to show any major alterations in FcR distribution. These preliminary results indicate cellular recognition of antibody-immune complexes may be impaired by subchronic exposure to road dust, which could decrease the immune response of road dust exposed animals.

Animals↗
PubMed1994

Autoantibodies to glutamate decarboxylase detected in diabetes-prone BB/OK rats do not distinguish onset of diabetes.

The diabetes syndrome of the BB rat resembles human Type 1 (insulin-dependent) diabetes including the prevalence of autoantibodies to the 64 kDa Beta-cell autoantigen, which has been identified as glutamate decarboxylase. This study aimed at detecting the prevalence and level of glutamate decarboxylase autoantibodies in 120-day-old diabetic and non-diabetic diabetes-prone BB/OK rats compared to those of sex- and age-matched diabetes-resistant LEW.1A rats. The antibodies were detected using semipurified glutamate decarboxylase from rat brain in two immunoassays, a direct and a sandwich enzyme-linked immunosorbent assay. For the last assay autoantibody-containing immunoglobulins of a serum from a patient with the stiff-man syndrome were used to bind specifically the enzyme as autoantigen in plastic wells. The antibody levels measured as optical density at 490 nm (x +/- SD)/prevalence of the diabetic group (120 +/- 29 days of age) of BB/OK rats 0.57 +/- 0.29 (n = 51)/88% as well as those of the nondiabetic group (121 +/- 26 days of age) with 0.51 +/- 0.29 (n = 32)/97% was significantly increased (p < 0.01) compared to those of the diabetes-resistant control group 0.15 +/- 0.06 (n = 29)/0%. Furthermore in a 209 +/- 27-day-old group (n = 21) of non-diabetic but diabetes-prone BB/OK rats the autoantibody levels of 1.21 +/- 0.39 vs 0.51 +/- 0.26 were further significantly enhanced (p < 0.01). These results were confirmed by a sandwich assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Age of Onset↗
PubMed1994

Implantation of non-toxic materials from glucose sensors: evidence for specific antibodies detected by ELISA.

After subcutaneous implantation of glucose sensors into LEW.1A rats, antibodies could be detected by means of enzyme-linked immunosorbent assay against the outer membrane (cellulose acetate) but not against either the inner membrane (polyethylene) or glucose oxidase (GOD). The kinetics of humoral immune response were investigated implanting different polymeric membranes such as polyurethane, cellulose acetate, regenerated cellulose. The highest antibody titer was detected against regenerated cellulose. There was no cytotoxic effect in vitro by any of the tested materials as examined on monolayer cultures of the mouse fibroblast cell line L-929. Thus immunogenicity is suggested to be considered as a parameter in biocompatibility testing of implantable medical devices.

Animals↗
PubMed1994

Experimentally induced malignant lymphoma due to chronic antigen stimulation.

Animal experiments were started in 1988 with the aim of inducing malignant lymphomas. 52 guinea pigs were exposed to potassium dichromate using the TINA test (plus 39 control animals). Following the sensitization procedure, the test animals and 15 control guinea pigs were exposed daily (5 x a week) epicutaneously to the antigen up to the present time. Currently, 30 exposed and 17 control animals are still in the experiment. In 3 out of 17 post-mortem examinations, histologically evident lymphomas were found. In the control animals, no tumor has been seen. The experiments support lymphoma causation by chronic antigen stimulation. The experiments are continuing.

Administration, Cutaneous↗
PubMed1994

Monoclonal antibodies specific to the glutamic acid decarboxylase 65 kDa isoform derived from a non-obese diabetic (NOD) mouse.

Two monoclonal antibodies specifically recognizing the 65 kDa isoform of the enzyme glutamic acid decarboxylase (GAD) were generated by fusion of spleen cells of a non-obese diabetic (NOD) mouse which had received a single intraperitoneal injection of 0.2 ml complete Freund's adjuvant followed three days later by one administration of a subdiabetogenic dose of streptozotocin (80 mg/kg body weight) three days before the fusion experiment was performed. Both monoclonals belong to the IgG1 isotype and were screened with an enzyme-linked immunosorbent assay using rat brain extract as a natural source of GAD and additionally with a capture assay by means of immunoglobulins of a patient with Stiff-man syndrome. The specific binding to the 65 kDa isoform of the enzyme was detected by a radioligand and an enzyme-linked immunosorbent assay using recombinant human glutamic acid decarboxylase specific for both the 67 and 65 kDa isoforms. Both monoclonal antibodies recognize the same antigenic epitope, which is located in the N-terminal region of the first 17 amino acids detected by fragments of human pancreatic 65 kDa GAD. Three out of 30 sera from Type 1 diabetic patients specifically displaced the binding of the monoclonals from 125I-labelled GAD65 measured by radio-immunoassay. A striking binding of both monoclonals M61/8F9 and M61/7E11 to the islets of cryosections of human, monkey, pig and rat pancreas but not to mouse pancreas was detectable. The antibodies failed to bind on the cell surface of viable rat islet cells. It is concluded that also in the diabetes-prone NOD mice GAD65 autoantibodies occur although GAD65 was not detectable in the mouse islets.

Animals↗
PubMed1994

Occurrence of islet cell reactive autoantibodies in diabetes-prone BB/OK rats is not associated with the onset of diabetes: a cross-sectional study of BB rats and their diabetes-resistant congenic strains.

Diabetes-prone BB rats are one of the extensively studied animal models of human type 1 (insulin-dependent) diabetes. We have detected islet cell reactive autoantibodies (ICRA) in sera of age-matched (120 days of age) diabetic and non-diabetic diabetes-prone BB/OK rats compared to sex- and age-matched diabetes-resistant LEW.1A control rats by cellular enzyme-linked immunosorbent assay (CELISA) using either desiccated or viable rat insulinoma (RIN) cells as target. The antibody levels measured using desiccated RIN cells (mean O.D. +/- SD; prevalence) of the diabetic group (1.41 +/- 0.59; 94.1%) and the non-diabetic group (1.23 +/- 0.48; 100%) were significantly (p < 0.01) increased compared to those of the diabetes-resistant LEW.1A control rats (0.24 +/- 0.1; 3.2%). Additionally, in a 209-day-old group of non-diabetic diabetes-prone BB/OK rats the autoantibody levels were further significantly (p < 0.01) increased (2.65 +/- 0.48; 100%). Comparing both congenic rat strains BB.1A/OK and LEW.1BB/OK, only the BB.1A/OK rats which bears the genetic background of diabetes-prone BB/OK rats were found to be antibody positive (0.68 +/- 0.43; 63.1%). The results were confirmed by the CELISA using viable RIN cells. We conclude that the prevalence of islet cell autoantibodies in diabetes-prone BB/OK rats and congenic BB.1A/OK rats is closely associated with the genetic susceptibility to diabetes and may be independent of Beta-cell destruction, but they are not a predictive marker for the onset of the disease in this animal model.

Aging↗
PubMed1994

A monoclonal antibody based enzyme-linked immunosorbent assay for the determination of GAD65, the smaller isoform of glutamic acid decarboxylase.

An enzyme-linked immunosorbent assay for GAD65, the smaller form of glutamic acid decarboxylase and an important autoantigen related to Type 1 diabetes, is described. The competitive binding assay is based on a monoclonal antibody specifically reactive with GAD65. The assay is suitable for quantification of this enzyme between 40 and 300 pg/microliter. The intraassay coefficients of variation (cv) are between 5.6% and 8.9% and the interassay cvs lie between 9.4% and 17.3%. The covalent binding of the antigen to magnetic beads as the solid phase makes the assay also applicable for quantification of GAD65 in tissue homogenates with a high concentration of detergent. The GAD65 content of islets isolated from newborn Lewis rat was detected to be 310 pg/islet. However, GAD65 was not detectable in mouse islets.

Animals↗
PubMed1993

Characterization of monoclonal islet cell reactive autoantibodies from the diabetic biobreeding (BB/OK) rat.

Two fusion experiments using the heteromyeloma cell line CB-F7 and splenocytes from two diabetes-prone BB (BioBreeding) rats at the onset of diabetes resulted in 128 islet cell reactive autoantibodies primarily detected with permeabilized insulin-producing rat insulinoma cells (RIN) by a cellular enzyme-linked immunosorbent assay. Seventy-nine (62%) of 128 RIN cell reactive supernatants exhibited a cross-reactivity with rat splenic lymphocytes. Six stable hybridomas secreting monoclonal ICSA (islet cell surface antibodies) were established, but only one monoclonal antibody, R4B10, showed preferential beta-cell binding. Six monoclonal antibodies showed a dual reactivity as ICA (islet cell cytoplasmic antibodies) detected by immunostaining of pancreatic islet cryosections and as ICSA on the surface of viable islet cells, whereas two reacted only with an ICA-like pattern. One monoclonal ICSA was specifically displaced from the RIN cell surface by sera of type 1 diabetic patients.

Animals↗
PubMed1993

Induction of islet cell surface and insulin antibodies in Balb/c mice by application of porcine insulin and Freund's adjuvant is not associated with insulitis.

To investigate whether insulin antibody (IAB) formation is associated with the appearance of islet cell cytoplasmic antibodies (ICA), islet cell surface antibodies (ICSA) and insulitis Balb/c Bln mice were immunized with porcine insulin in combination with or without Freund's adjuvant. The animals received 8 i.p. injections and were followed up to 150 days for the development of antibodies and insulitis. Mice immunized with insulin in CFA developed IAB as well as ICSA. Mice only receiving Freund's adjuvant emulsified in saline also developed ICSA. ICA were not detectable. Inflammatory infiltrates were found in the exocrine pancreatic parenchyma but not in islets. The results show that nonspecific stimulation of the immune system and the application of insulin as antigen leads to both the formation of ICSA and IAB, while insulitis was not detectable.

Animals↗
PubMed1992

Monoclonal antibody-mediated cytotoxicity against rat beta cells detected in vitro does not cause beta-cell destruction in vivo.

Two monoclonal Beta-cell surface antibodies M10H6 und K14D10 were obtained by fusion of spleen cells of Balb/c mice with the myeloma cell line P(3)0. The monoclonal antibody M10H6 was induced by immunization with rat insulinoma cells finally boostered with disintegrated rat islets, whereas the K14D10 was generated after immunization with porcine proinsulin. Both monoclonals belong to the IgG2A isotype and were screened with insulin-producing rat insulinoma cells by an indirect immunofluorescence test as well as by a cellular enzyme linked immunosorbent assay. In addition to the cell surface binding on living Beta cells the monoclonals react with islets on cryostat sections of rat pancreas. The anti-islet cytotoxic potential of these monoclonals was measured by 51Chromium-release in the presence of complement or Fc-receptor bearing leucocytes using 51Chromium-labelled rat islet cells as target. Both antibody secreting hybridomas were propagated in syngeneic mice resulting in high levels of islet cell surface antibodies in ascites and sera from the recipient. High anti-islet cytotoxicity was mediated by ascites fluid, but no mouse developed hyperglycaemia. Furthermore, the repeated injections of the monoclonals into rats did not exert a diabetogenic action and failed to reduce the pancreatic insulin content although the attraction of the K14D10 to the pancreatic islets in vivo could be demonstrated. We conclude that islet cell surface antibody-mediated Beta-cell lysis in vitro may not be relevant to Beta-cell destruction in vivo.

Animals↗
PubMed1992

Characterization of two porcine proinsulin reactive monoclonal antibodies by immunostaining of beta-cells in pancreatic sections of different species.

Murine monoclonal antibodies against porcine proinsulin were generated by somatic cell hybridization. As detected by radioimmunoassay, 2 monoclonal antibodies KSPI14D4 and KSPI13G10 showed a strong binding to 125I-labelled porcine proinsulin but not to insulin. The species specificity of these 2 monoclonals was found to be different as shown by indirect immunofluorescence using sections of Bouin-fixed pancreata of different species. The KSPI14D4 recognized the proinsulin of pig, mouse, man, cattle, rat, dog, and cat but not that of guinea pig, whereas the KSPI13G10 bound to porcine proinsulin only. From these results it is concluded that KSPI14D4 effectively recognizes a wide-spread epitope located in one of the insulin-C-peptide junctions of the proinsulin molecule, whereas KSPI13G10 is directed to a species-specific epitope of the porcine connecting peptide.

Animals↗
PubMed1992

Detection of antibodies against both isoforms of glutamate decarboxylase in BB/OK rats by western blotting and immuno trapping enzyme activity assay.

The GABA-producing enzyme glutamate decarboxylase (GAD) is a prominent autoantigen in insulin-dependent diabetes mellitus (IDDM). Autoantibodies against GAD were found with a high prevalence in IDDM patients and in animal models for IDDM. The aim of this study was to detect autoantibodies against both isoforms of GAD in diabetic and non-diabetic but diabetes-prone BB/OK rats by Western blotting and to test their specificity to GAD by an immuno-trapping enzyme activity assay. Eighteen diabetic and 18 non-diabetic BB/OK rats (age 121 +/- 20 days) were investigated. In 10/18 (56%) of the diabetic and 13/18 (72%) of the non-diabetic BB/OK rats autoantibodies against at least one GAD-isoform were detected by Western blotting. In the immunotrapping enzyme activity assay, the mean value of the diabetic (1151 +/- 552 cpm, n = 11) and nondiabetic BB/OK rats (1978 +/- 1213 cpm, n = 10) was significantly (p < 0.01) increased compared to the LEW. 1A control rats (581 +/- 274 cpm, n = 12). 7/10 (70%) individual sera of the non-diabetic and 5/11 (45%) of the diabetic BB/OK rats were positive in this test. In conclusion, the prevalence of GAD autoantibodies in BB/OK rat is connected with the genetic susceptibility to IDDM but is not a predictor for the onset of the disease in BB/OK rats.

Animals↗
PubMed1992

[Cerebral multisystem atrophy in a patient with depressive hallucinatory syndrome. A case report].

In a female patient, aged 47 years at the beginning, the successive appearance of extrapyramidal signs preceded by depression, paranoid-hallucinatory psychosis, autonomic and cerebellar dysfunction was followed up over a period of 8 years. Autopsy revealed--in accordance with the clinical symptomatology--both olivo-ponto-cerebellar atrophy and a striatonigral degeneration. As a rule these changes are accompanied by dementia. The reported case is unusual in having first presented with severe depression and paranoid-hallucinatory symptoms.

Brain Stem↗