Biomedical subjects

M Ziegler

Publications and source records attributed to M Ziegler.

At least 91 records · Page 5Linked to original sources

PubMed1997

Alzheimer caregiver stress: basal natural killer cell activity, pituitary-adrenal cortical function, and sympathetic tone.

The association between Alzheimer caregiving and natural killer (NK) cell activity and basal plasma levels of adrenocorticotropic hormone (ACTH), cortisol, beta-endorphin, prolactin, epinephrine, norepinephrine, and neuropeptide Y was determined in 100 spousal Alzheimer caregivers and 33 age- and gender-comparable control volunteers upon intake into a study of the psychological and physiologic impact of caregiving. The relationship between these physiologic measures and individual characteristics such as age, gender, medical status, severity of stress, severity of depressive symptoms, and caregiver burden was tested. In addition, the association between NK activity and alterations of the neuroendocrine measures was investigated. As compared to controls, the Alzheimer caregivers had similar levels of NK activity and of basal plasma neuroendocrine hormones and sympathetic measures. While older age and male gender status were associated with increased levels of ACTH, neither medical caseness, severity of life stress, nor severity of depressive symptoms was associated with alterations in any of the multiple physiologic domains. Classification of Alzheimer caregiver burden identified caregivers who were mismatched in terms of the amount of care they were required to provide and the amount of respite time received. The mismatched caregivers had significantly higher basal plasma ACTH but no change in other physiological measures, as compared to non-mismatched caregivers. NK activity was negatively correlated with plasma levels of neuropeptide Y but not with any of the other neuroendocrine measures. Based on this cross-sectional evaluation of NK activity and neuroendocrine and sympathetic measures, we conclude that most Alzheimer caregivers do not show evidence of altered basal physiology.

Adaptation, Psychological↗

PubMed1997

[Palliative treatment for pain in osseous metastasized prostatic carcinoma with osteotropic rhenium-186 hydroxyethylidene diphosphonate (HEDP)].

Systemic administration of strontium-89 is an important option for pain relief in advanced prostate carcinoma with multiple osseous metastases. Recently, rhenium-186-HEDP was introduced as a new substance which has important advantages (shorter physical half-life, scintigraphic imaging, dose distribution). The myelosuppressive effect can be estimated more accurately in advance, so that adverse effects can be reduced and the treatment can be repeated after a shorter period of time and more often. Our study comprises 15 treatments with rhenium-186-HEDP in advanced prostate cancer patients using the 1.4- to 2-fold standard dose. The response rate, estimated as reduction in pain and increase in patient mobility, was 87% with no major myelosuppressive effects. The mean duration of pain relief was 4-6 weeks. All four patients with repeated therapy were also responding to the second treatment. Radionuclide therapy for painful osseous metastases with rhenium-186-HEDP appears to be an effective and, even at higher doses, safe procedure.

Aged↗

PubMed1997

Sensitive monoclonal antibody-based sandwich ELISA for determination of the diabetes-associated autoantigen glutamic acid decarboxylase GAD65.

Although various methods for the detection of autoantibodies against glutamic acid decarboxylase (GAD65-AAb) are known, no sensitive method for the quantification of GAD65 as autoantigen is available. We describe a sandwich ELISA based on monoclonal GAD65 antibodies (Mc-GAD65-Ab) of different epitope specificities to quantify GAD65 in pancreatic islets and in different organ/cell extracts and during the preparation of GAD from brain extracts. GAD65 was captured via solid phase coated Mc-GAD65-Ab and detected via a second biotin-labelled Mc-GAD65-Ab recognizing a NH2-terminal epitope of the molecule. The detection limit was estimated to be 0.03 ng GAD65/ml using alkaline phosphatase (AP)-conjugated streptavidin. GAD65 contents in islets of neonatal BB/OK rats and Lewis rats amounted to 37.4 and 43.7 pg/islet, respectively. Furthermore, GAD65 was quantified in brain extracts of pig (55.1 ng/mg protein), mouse (39.5 ng/mg), rat (243.8 ng/mg) and pig cerebellum (514.8 ng/mg) and in different organ extracts of Lewis rat.

Animals↗

PubMed1997

Immunohistochemical differentiation of monoclonal GAD antibodies recognizing linear or conformational epitope regions.

GAD65 is targeted by different patterns of autoantibodies [glutamic acid decarboxylase (GAD)-AAbs] in insulin-dependent diabetes mellitus (IDDM) and stiff-man syndrome (SMS). To study differentiation of the GAD-AAb pattern by immunohistochemistry, we examined the immunostaining of 15 monoclonal GAD antibodies (mc-GAD-Abs), which recognized different epitope regions of the antigen, on human pancreatic sections that were unfixed or fixed with different fixatives. By a competitive sandwich enzyme-linked immunosorbent assay (ELISA), three binding patterns of mc-GAD-Abs were identified: 5 of 15 mc-GAD-Abs recognized a linear N-terminal epitope (p1), 5 of 15 were reactive with a conformational GAD65 epitope region (p2), and 5 of 15 were cross-reactive with GAD67 (p3). These patterns of mc-GAD-Abs were tested for islet cell binding by indirect immunofluorescence on pancreatic sections treated with either (1) Bouin's solution, (2) Zamboni's solution, or (3) phosphate-buffered formaldehyde for 0.5, 1, 2, and 18 h at 4 degrees C. After fixation for up to 2 h no differentiation of immunoreactivity of patterns was observed using the three fixatives. mc-GAD-Abs recognizing conformational epitope regions (p2) revealed a marked reduced immunoreactivity on pancreatic sections fixed for 18 h with 4% formaldehyde, while mc-GAD-Abs reactive with linear epitopes (p1, p3) were detectable with strong binding. This fixation procedure was used to compare the immunoreactivity of GAD-AAb+ or GAD-AAb- islet cell cytoplasmic antibody-positive (ICA+) sera of IDDM (n = 27) and SMS patients (n = 3). The three SMS sera were reactive with GAD on fixed islets but showed a reduced titer, whereas the majority of IDDM sera (22/27; 81.5%) were not detectable; 70.6% (12/ 17) of GAD-AAb+ IDDM sera were not detectable on fixed islets. Furthermore, all 10 GAD-AAb- IDDM sera tested failed to react with fixed pancreas, which also suggested an alteration of non-GAD-ICA antigens. In conclusion, the fixation of human pancreatic sections with formaldehyde for 18 h allows the differentiation of GAD-AAbs recognizing linear and conformational epitope regions.

Animals↗

PubMed1997

Bovine liver mitochondrial NAD+ glycohydrolase. Relationship to ADP-ribosylation and calcium fluxes.

Mitochondrial NAD+ glycohydrolase (NADase) has been proposed to be required for (nonenzymatic) ADP-ribosylation and subsequent activation of a Ca2+ release pathway. In our studies it has been found that several agents including nicotinamide, dithiothreitol, and EDTA exert no or little effect on ADP-ribosylation in isolated bovine liver mitochondria, while strongly inhibiting the NADase. The NADase did, however, catalyze the formation of cyclic purine nucleoside diphosphoriboses (similar to cyclic ADP-ribose) from NAD+ analogs. It appears possible, therefore, that this enzyme may be involved in the regulation of mitochondrial Ca2+ fluxes by forming a potent Ca(2+)-mobilizing agent, rather than by providing the substrate for non-enzymatic ADP-ribosylation.

Adenosine Diphosphate Ribose↗

PubMed1997

[Renovascular arterial hypertension: current aspects of physiopathology, diagnosis and treatment].

Renovascular hypertension is a potentially curable, secondary form of hypertension. It is caused by renal ischemic disease, which remains a significant clinical problem because of the increasing incidence of atherosclerosis with aging of the overall population. The role of the reinin-angiotensin system in renovascular hypertension has been consolidated by the discovery of angiotensin II receptor subtypes, various tissue renin-angiotensin systems and the function of angiotensin II as a vascular growth factor. To date renal vein renin estimation and converting enzyme renography seem to be the most reliable investigations to demonstrate the hypertensive role of a kidney before revascularization. Percutaneous transluminal angioplasty is a successful treatment in selected forms of renal artery stenosis. Open surgery consists of either bypass procedure or renal autotransplantation with extracorporeal reconstruction of the renal vasculature in cases of aneurysms or segmental renal artery stenoses. Control of hypertension and, increasingly important, preservation of renal function can be safely and successfully achieved, on the basis of careful diagnosis and individual selection of the therapeutic procedure are performed.

Adult↗

PubMed1997

[Retroperitoneal cystic lymphangioma in a child].

Cystic lymphangiomas are rare, benign tumors, which are mainly located in the neck or axilla. The fourteenth reported case in the literature of a pediatric retroperitoneal cystic lymphangioma is described. Symptoms, diagnostic procedure and therapy are reported and discussed.

Child↗

PubMed1997

[Congenital cysts of the seminal vesicles with ipsilateral kidney agenesis. Clinical aspects of 7 cases].

Seminal vesicle cysts with ureteral ectopy and ipsilateral renal agenesis or dysplasia are rare congenital malformations. This study reports 7 consecutive cases in a single center and, for the first time in the literature, reports long-term results on 5 cases. Patients were between the age of 15 and 57 years. The malformation was diagnosed in all cases with excretory urography, computed tomography, magnetic resonance imaging and cystoscopy. 5 patients were followed after diagnosis for 26 to 119 months (mean 52 months). Only 2 of 7 patients primarily presented with nonspecific lower urinary tract symptoms. One patient (15 years old) showed significant enlargement of the cysts with compression of the urinary bladder and signs of urinary incontinence 10 years after primary diagnosis. The other 4 patients had no changes of their malformation. In conclusion, seminal vesicle cysts with ipsilateral renal agenesis are now more frequently diagnosed because of the increasing use of sectional imaging procedures. They are mostly asymptomatic and their morphology does not change with time. These data support the concept of only treating symptomatic patients.

Adolescent↗

PubMed1997

[Are diagnostic codes in accordance with the SGB V regulation and classification of case fees and special charges a suitable instrument for controlling costs in surgery?].

The German health care system lacks transparency of efficiency and costs. Fixed compensations for common diagnoses and treatments were established to lower spending and to get better statistics of diagnoses and treatments. It could be demonstrated that the expenses are too high while the benefit is too small.

Cost Control↗

PubMed1996

NAD+ analogs substituted in the purine base as substrates for poly(ADP-ribosyl) transferase.

Poly(ADP-ribosyl) transferase (pADPRT) catalyzes the transfer of the ADP-ribose moiety from NAD+ onto proteins as well as onto protein-bound ADP-ribose. As a result, protein-bound polymers of ADP-ribose are formed. pADPRT itself contains several acceptor sites for ADP-ribose polymers and may attach polymers to itself (automodification). In this study the influence of substitutions in the purine base of NAD+ on the polymerization reaction was investigated. The adenine moiety of NAD+ was replaced by either guanine, hypoxanthine or 1,N6-ethenoadenine. These analogs served as substrates for polymer synthesis as judged from the extent of automodification of the enzyme and the sizes of the polymers formed. Time course experiments revealed that 1,N6-etheno NAD+ (epsilon-NAD+) and nicotinamide hypoxanthine dinucleotide (NHD+) were rather poor substrates as compared to NAD+. Synthesis of GDP-ribose polymers from nicotinamide guanine dinucleotide (NGD+) was more efficient, but still significantly slower than poly(ADP-ribosyl)ation of the enzyme using NAD+. The size of the different polymers appeared to correlate with these observations. After 30 min of incubation in the presence of 1 mM substrate, polymers formed from epsilon-NAD+ or NHD+ contained up to 30 epsilon-ADP-ribose or IDP-ribose units, respectively. Using NGD+ as substrate polymers consisted of more than 60 GDP-ribose units, an amount similar to that achieved by poly(ADP-ribosyl)ation in the presence of only 0.1 mM NAD+ as substrate. These results suggest that the presence of an amino group in the purine base of NAD+ may facilitate catalysis. Substitution of the nicotinamide moiety of NAD+ with 3-acetylpyridine had no detectable effect on polymer formation. Oligomers of GDP-ribose and epsilon-ADP-ribose exhibited a slower mobility in polyacrylamide gels as compared to ADP-ribose or IDP-ribose oligomers. This feature of the two former analogs as well as their markedly attenuated polymerization by pADPRT provide valuable tools for the investigation of the enzymatic mechanism of this protein. Moreover, polymers of epsilon-ADP-ribose may be useful for studying enzymes degrading poly(ADP-ribose) owing to the fluorescence of this analog. Digestion of epsilon-ADPR polymers with snake venom phosphodiesterase was accompanied by a significant fluorescence enhancement.

Adenosine Diphosphate Ribose↗

PubMed1996

Characterization of detergent-solubilized beef liver mitochondrial NAD+ glycohydrolase and its truncated hydrosoluble form.

Membrane-bound beef liver mitochondrial NAD+ glycohydrolase (NADase) was partially purified after its solubilization by either detergent or crude pancreatic lipase, steapsin. Solubilization by steapsin yielded a homogeneous water-soluble enzyme. A fluorescence assay was developed that allowed visualization of NADase activity directly within the gel after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The apparent molecular masses of the detergent- and steapsin-solubilized forms were estimated to be about 30,000 and 28,000, respectively. The small part that was cleaved by steapsin represents presumably the membrane anchor of the mitochondrial NADase, as its removal converted the enzyme from a highly hydrophobic to a hydrosoluble protein. The fluorescence staining for activity was also successfully applied to other NADases. Kinetic analyses of the two forms of solubilized mitochondrial NADase revealed that the catalytic properties were unaffected after the steapsin treatment. Neither the binding affinity of the substrate analog 1, N6-etheno-NAD+ nor the inhibition by nicotinamide differed significantly between these two forms of the enzyme. Moreover, the dependence of the enzyme activity on temperature, pH, or ionic strength was also similar for both preparations. However, activity of the detergent-solubilized but not of the truncated steapsin-solubilized enzyme was strongly dependent on the presence of bivalent metal ions such as ZN2+. These results suggest that the membrane part of the mitochondrial NAD+ glycohydrolase is not required for catalysis. It appears, however, to be of importance for the regulation of the enzyme.

Animals↗

PubMed1996

Selection toward diploid cells in prostatic carcinoma derived cell cultures.

For elucidation of the growth-regulatory mechanisms in prostatic carcinoma, in vitro investigations on prostatic cell cultures are required. However, one major problem of cell culturing is the selection of particular cell types such that the cell lines representing only some of the features as compared with the tumor of origin. We studied the chromosomal composition of 20 prostatic tissue-derived cell cultures and 12 original (fresh) tissue specimens that were obtained from 13 patients with prostatic adenocarcinoma. Using fluorescence in situ DNA hybridization (FISH), evident clonal abnormalities were detected in 78% of the fresh cancer samples and in 47% of the cultured cancer samples. Of the seven cases revealing clonal abnormalities in the fresh cancer specimen, aneuploidy was detected in only two samples after cell culturing at the earliest passage studied. The aneuploid cell populations in the cultured samples were all lost during progressive subcultivation (after passage 4). Interestingly, by performing FISH on cytogenetic preparations aneuploidy was confined to the interphases, with the metaphases being found to be diploid. This finding indicates that the aneuploid cells have a proliferation disadvantage in cell culture resulting in an overgrowth of diploid cells.

Adenocarcinoma↗

PubMed1996

Murine monoclonal glutamic acid decarboxylase (GAD)65 antibodies recognize autoimmune-associated GAD epitope regions targeted in patients with type 1 diabetes mellitus and stiff-man syndrome.

To study the immune response to glutamic acid decarboxylase (GAD) in insulin-dependent diabetes mellitus, monoclonal GAD antibodies after fusion of splenocytes from a nondiabetes-susceptible BALB/c mouse immunized with human recombinant GAD65 were generated. Of the 44 monoclonals, 35 are specific for the GAD65 isoform, whereas 9 also react with GAD67. Some 37 monoclonals, including all GAD65/67 reactive antibodies, react with GAD by Western blot analysis. The remaining 7 GAD65 monoclonals bind GAD only in an immunoprecipitation assay, which implies that they target epitopes dependent on the conformation of the GAD molecule. The 125I-GAD binding of the GAD65 monoclonals reactive on Western blotting was significantly diminished by all 3 sera from Stiff-man syndrome patients but only by 3/30 (10%) sera from type 1 diabetic patients. In contrast, the 7 monoclonal antibodies reactive with a conformation-dependent GAD epitope were competitive with 83% of GAD-autoantibody-positive sera from these diabetic patients. Using chimeric GAD65/67 proteins, the epitope region targeted by these monoclonals was mapped to the middle of GAD65 (amino acids 221-442). This central conformation-dependent GAD region was also targeted by sera from patients with type 1 diabetes. In conclusion, our data show that even after common immunization of a nondiabetes-susceptible mouse strain, monoclonal were obtained which preferentially react with the GAD65 linear amino-terminus (amino acids 4-17) and a conformation-dependent region located in the middle of GAD targeted by autoantibodies, indicating that this GAD region is not restricted to the autoimmune response associated with the Stiff-man syndrome and the beta-cell destruction in type 1 diabetes mellitus.

Animals↗

PubMed1996

Antibody response to islet antigens in anti-CD4/prednisolone immune intervention of type 1 diabetes.

Cytoplasmic islet cell antibodies, glutamic acid decarboxylase autoantibodies, spontaneous insulin autoantibodies, and insulin-induced antibodies were analyzed in a 1-year follow-up study of 12 newly diagnosed patients with insulin-dependent diabetes mellitus aged 14 +/- 2 years (range 7-20 years) who had been initially treated with either multiple injections of insulin alone (control group) or, in addition, anti-CD4 monoclonal antibody/prednisolone (treatment group). Despite individual variations in islet cell antibody titers, there were no significant differences in the prevalence or changes in the mean titers between the two groups. Glutamic acid decarboxylase autoantibodies remained almost unchanged, but correlated with levels of islet cell antibodies. While at initiation of treatment only 50% of the patients from both groups had spontaneous insulin autoantibodies, all patients developed insulin-induced antibodies upon conventional insulin therapy during the course of follow-up. This was not related to islet cell antibody or glutamic acid decarboxylase antibody levels. The insulin requirement was markedly reduced through the period of follow-up, but did not significantly differ between the two groups. A correlation between islet cell antibody levels and insulin requirement was observed in the control group but not in the treatment group. Plasma levels of the antibodies were not associated with changes in stimulated C-peptide or hemoglobin A1 concentrations. Activated T-lymphocytes persisted in both groups of patients, but their mean levels were not significantly different. The reason for the absence of statistically significant differences between treatment and control groups could be due to the small number of patients in the study. In conclusion, short-term immune intervention with anti-CD4 monoclonal antibody in addition to insulin therapy did not suppress autoimmune reactions towards the beta cells.

Adolescent↗

PubMed1996

[Leydig cell tumors of the testis--clinical and morphologic aspects].

Leydig cell tumors are the most common tumors of the gonadal stroma. They account for 3% of all testicular tumors. Whereas in 10% of adult cases malignancy occurs, the clinical course in children is benign. During childhood the tumor presents with precocious pseudopuberty, in adults with testicular swelling and gynecomastia. We report on 17 cases of Leydig cell tumor, paying special attention to clinical and morphological aspects.

Adult↗

PubMed1996

Comparison of the islet cell antibody pattern of monoclonal glutamic acid decarboxylase antibodies recognizing linear and conformational epitopes.

In order to compare the reactivity of glutamic acid decarboxylase (GAD) antibodies recognizing linear and conformational epitopes as islet cell cytoplasmic antibodies (ICA), monoclonal antibodies were generated. An ELISA displacement test using two biotinylated monoclonals recognizing a linear (M61/7E11) or a conformational GAD65 epitope (M65/6B12) was performed to identify epitope regions recognized by monoclonal GAD antibodies. The GAD binding by monoclonal GAD antibodies was tested by immunofluorescence on fixed and unfixed pancreatic sections of human, rat, and mouse, and by Dot-blot experiments. 16/23 (69.6%) of the monoclonals were specifically reactive with GAD65 and 7/23 (30.4%) were reactive with both GAD isoforms. 8/16 (50%) of monoclonal GAD65 antibodies recognized a linear GAD epitope located at the N-terminus (pattern 1). 5/16 (31.3%) displaced M65/6B12, indicating the recognition of a conformational GAD epitope (pattern 2). Monoclonals belonging to patterns 1 and 2 showed strong ICA binding. 3/16 (18.8%) of monoclonals specific for GAD65 with weak or no immunostaining of pancreatic islets (pattern 3) did not inhibit the binding of both biotinylated antibodies in the displacement test, indicating other epitope specificities. In conclusion, GAD antibodies recognizing both conformational and linear epitopes of the GAD65 molecule are involved in ICA binding with strong reactivity. Furthermore, results obtained with monoclonals of pattern 3 suggest the occurrence of GAD65 epitopes partly inaccessible on cryosections, which may result in an ICA-negative test of GAD65 autoantibody positive sera.

Animals↗

PubMed1996

Glutamate decarboxylase (GAD) is not detectable on the surface of rat islet cells examined by cytofluorometry and complement-dependent antibody-mediated cytotoxicity of monoclonal GAD antibodies.

After fusion of splenocytes from a Balb/c mouse which received three injections of human recombinant GAD65 44 hybridomas producing monoclonal GAD antibodies (mc-GAD Ab) could be established. 35 out of the 44 mc-GAD Ab specifically recognized the GAD65 isoform, whereas 9 showed a cross-reactivity with GAD67. All antibodies belong to the IgG class. The mc-GAD Ab were reactive with recombinant as well as natural GAD tested in enzyme-linked immunosorbent assay. Twenty-one antibodies stained islet cells very well in cryosections of human, monkey, rat, and pig pancreas. However, the mc-GAD Ab failed to bind on the surface of viable rat islet cells, although they reveal a striking binding on permeabilized cells examined by cytofluorometry. Furthermore, the mc-GAD Ab were analyzed for complement-dependent antibody-mediated cytoxicity (C'AMC) to rat islet cells. Whereas our monoclonal Beta-cell specific surface antibody K14D10 caused a high C'AMC measured as a 51Cr-release of 56.5 +/- 4.6%, n = 10, only 4/44 mc-GAD Ab provoked a moderate increase of 51Cr-release ranging from 7.1-10.5% (cut-off 7.0%). From these findings it is suggested that GAD is not detectable on the islet-cell surface by binding and cytotoxicity test.

Animals↗

PubMed1996

[Electrophysiologic diagnosis in erectile dysfunction].

So far, electrophysiological examinations have rarely been used in the diagnosis of erectile dysfunction (ED) mainly because the methods available only allow somatic neuron pathways to be examined whose relevance for the mainly autonomically controlled crection is evaluated differently. At present, impaired penile nerve supply as the possible cause of ED can only be evaluated through neurophysiological screening of the somatic and autonomic pathways of the pelvic floor, and not just by one simple method. Diagnosing ED should include testing of motoric efferences through electroneurography of the pudendal nerve and electromyography of the external anal sphincter and the urethral sphincter. Sensitive afference is tested with somatosensory evoked potentials of the pudendal nerve. New methods that are available for the examination of autonomic pathways are the penile sympathetic skin response and the EMG of the corpus cavernosum. Together with the other electrophysiological examinations, they allow neurogenic causes to be determined and differentiate not only between central and peripheric lesions, but also between acute and chronic changes. Prognosis can also be estimated. A crucial diagnostic deficit is the fact that it is still not possible to test the parasympathetic system directly.

Autonomic Nervous System↗