Biomedical subjects

M Ziegler

Publications and source records attributed to M Ziegler.

At least 181 records · Page 10Linked to original sources

PubMed1991

Segmental renal hypoplasia of vascular origin causing renal hypertension in a 3-year-old girl.

A rare case of renal hypertension in a 3-year-old girl caused by segmental renal hypoplasia of vascular origin is presented. Resection of the hypoplastic segment of the kidney permitted successful treatment of the high blood pressure with preservation of renal function. Elevated plasma renin activity in the renal vein of the affected side and biochemical investigations demonstrated that the resected segment of the renal cortex was the source of the renin leading to hypertension by activation of the renin-angiotensin-aldosterone system.

Child, Preschool↗

PubMed1991

[Observations on the formation of the secondary venous system of the abdominal cavity with special reference to idiopathic left-sided varicocele].

Based on 1,778 radiologic investigations of vena cava inferior, left renal vein and left spermatic vein the anomalies due to incorrect transformations from the first to the second abdominal venous system are presented. A persistent vena cardinalis posterior could be demonstrated in two cases. Varicoceles were seen with and without insufficient valves of the spermatic vein and venous outflow obstruction of the renal vein, respectively. Based on the demonstrated phlebographies disorders of ontogenesis seem to be the cause of the idiopathic left-sided varicoceles.

Abdomen↗

PubMed1991

[Magnetic resonance tomography in the differential diagnosis of pathologic changes in scrotal contents--a comparison with computed tomography].

48 patients with scrotal pathology were examined by magnetic resonance tomography (MRI) and computed tomography (CT). The diagnostic results were compared to surgical and histological findings. The correct diagnosis could be detected in 81% by CT and in 85% by MR. Another 27 patients were examined only by MR with positive results in 88%. Demonstration of tunica albuginea, imaging of testes in various planes and diagnostic accuracy in about 88% with missing ionising irradiation make MRI the most reliable diagnostic imaging in the classification of scrotal pathology. False negative results were found in 1/48 by CT and none by MRI. False positive results could be found in 2/75 of MRI examinations but none in CT.

Abscess↗

PubMed1991

Determinants of retrovirus gene expression in embryonal carcinoma cells.

The expression of Moloney murine leukemia virus is restricted in embryonal carcinoma (EC) cells. To characterize specific mutations necessary for expression of retroviruses in EC cells, we analyzed the expression of retrovirus mutants and recombinants thereof in EC cell lines F9 and PCC4. DNA sequence comparison and functional studies allowed us to define three point mutations in the enhancer region of the viral mutants at positions -345, -326, and -166 and two point mutations within the 5'-untranslated region of the viral genome at positions +164 and +165 that were essential for retrovirus expression in EC cells. DNA fragments derived from either the wild type or mutant viruses were used to search for sequence-specific DNA-binding factors in nuclear extracts from undifferentiated PCC4 cells. A cellular factor was found to bind strongly to sequences within the enhancer region (-354 to -306) of wild-type viruses but only weakly to sequences derived from mutant viruses. This factor was named ECF-I (for EC cell factor I). Retroviral expression in EC cells correlates with decreased binding affinity for ECF-I.

Animals↗

PubMed1991

A single point mutation activates the Moloney murine leukemia virus long terminal repeat in embryonal stem cells.

The expression of Moloney murine leukemia virus (Mo-MuLV) and Mo-MuLV-derived vectors is restricted in undifferentiated mouse embryonal carcinoma and embryonal stem (ES) cells. We have previously described the isolation of retroviral mutants with host range properties expanded to embryonal cell lines. One of these mutants, the murine embryonic stem cell virus (MESV), is expressed in ES cell lines. Expression of MESV in these cells relies on DNA sequence motifs within the enhancer region of the viral long terminal repeat (LTR). Here we show that replacement of the Mo-MuLV enhancer region by sequences derived from the MESV LTR results in the activation of the Mo-MuLV LTR in ES cells. The enhancer regions of MESV and Mo-MuLV differ by seven point mutations. Of these, a single point mutation at position -166 is sufficient to activate the Mo-MuLV LTR and to confer enhancer-dependent expression to Mo-MuLV-derived retroviral vectors in ES cells. This point mutation creates a recognition site for a sequence-specific DNA-binding factor present in nuclear extracts of ES cells. This factor was found by functional assays to be the murine equivalent to human Sp1.

Base Sequence↗

PubMed1991

Postradiation lower motor neuron syndrome presenting as monomelic amyotrophy.

Monomelic amyotrophy developed 16 months, nine and 12 years after irradiation of the lumbosacral spinal cord for seminoma in one patient and for Hodgkin's disease in two others. In two patients, involvement was clinically limited to one leg, with a subacute course followed by plateau in the first case and with progressive worsening in the second one. In the third patient, the course was progressive with involvement of the other lower limb occurring five years later. From clinical and electrophysiological data, it seems probable that the disease process was a result of a selective injury to the lower motor neuron in the lower spinal cord.

Adult↗

PubMed1991

(99mTc)-HM-PAO SPECT and cognitive impairment in Parkinson's disease: a comparison with dementia of the Alzheimer type.

Regional cerebral perfusion was evaluated by single photon emission tomography (SPECT) using (99mTc)-HM-PAO as a tracer, in thirty Parkinsonian patients with (n = 15) or without (n = 15) dementia, nineteen patients with dementia of the Alzheimer type (DAT) and thirteen control subjects. HM-PAO uptake was measured in the frontal, parietal, temporal and occipital cortex and tracer perfusion was expressed as cortical/cerebellar activity ratios. Regional HM-PAO ratios in nondemented Parkinsonian patients did not differ from controls, whereas in demented patients with Parkinson's disease (DPD) a significant reduction was found in the parietal, temporal and occipital cortex. Tracer uptake ratios were significantly reduced in all regions in the DAT group. Thus DPD and DAT shared a common pattern of marked posterior hypoperfusion, although the perfusion defect was greater and more extensive in the DAT patients.

Aged↗

PubMed1991

Effects of prostaglandins and prostaglandin synthetase inhibitors on acutely obstructed kidneys in the dog.

An intact canine model was developed to study the effects of prostaglandins (PG) and prostaglandin synthetase inhibitors on acutely obstructed kidneys. Totally implanted nephrostomy tubes were placed to measure renal pelvic pressure. Complete ureteral obstruction was obtained with a Fogarty balloon catheter inflated in the distal ureter; by this method renal pelvic pressure reached 40-50 mm Hg. Renal pelvic pressure was reduced after intravenous indomethacin and dipyrone administration, whereas blood pressure showed no major changes. Exogenous prostaglandins had both immediate and contrary effects: PGE2 caused a significant decrease, whereas PGF2 alpha caused a significant increase in renal pelvic and blood pressure. The reduced rise in renal pelvic pressure appears to be the main reason for the analgesic effects of prostaglandin synthetase inhibitors. The efficiency of these drugs in the treatment of renal colic is supported by this study, that of prostaglandins cannot be proved.

Acute Disease↗

PubMed1991

Organ-preserving surgery in renal cell carcinoma--change of the therapeutical concept.

From 1976 to 1989 in 90 patients (n = 98 tumors) with renal cell carcinoma organ-preserving surgery was performed (age 25-84 years, mean 58 years). Imperative indications for organ preservation (tumor removal by partial resection with or without clamping of the artery, autotransplantation) (n = 18) were chronic renal failure, benign pathology of contralateral kidney, functional or anatomical solitary kidney, and bilateral tumors. Elective organ-preserving surgery (n = 72) was done for small peripherally located lesions and in cases of uncertain preoperative tumor dignity. Tumors removed for imperative indications were 2-11 cm (mean 6.5 cm) in size. In the elective group tumor size ranged from 1 to 6 cm (mean 3.5 cm). Follow-up was 3 months to 13 years, 1 postoperative mortality was observed in the group with imperative indication. 15/90 patients are alive without tumor, 1 patient with metastasis, 1 patient died because of metastasis and 1 for unrelated reasons. All patients beside 1 in the group with elective indication are alive without metastasis. Renal cell carcinoma has changed its clinical feature. More and more tumors are detected by ultrasound without clinical symptoms. Though radical tumor nephrectomy still is the standard operation for renal cell cancer, in cases especially with small tumors the indication for organ-preserving operation with regard to these excellent results should be given more often.

Carcinoma, Renal Cell↗

PubMed1991

Mathematical modelling of competitive labelled-ligand assay systems. Theoretical re-evaluation of optimum assay conditions and precision data for some experimentally established radioimmunoassay systems.

A mathematical theory of competitive labelled-ligand assays was developed with the intention of theoretically re-evaluating the optimal assay conditions and precision data of assay systems established by experiment. Our theory is based upon the assumptions of a simple bimolecular reaction mechanism, homogeneous reactants, as well as kinetically indistinguishable labelled and non-labelled ligands. The general case of two-step (non-equilibrium) assay was considered including the one-step (equilibrium) assay as a special case. The solution of the system of corresponding kinetic differential equations was used to mathematically construct standard curves. Furthermore, intraassay precision profiles and indices as well as detection limits were calculated considering solely the pipetting error, epsilon, as a source of experimental error. A procedure was outlined to mathematically determine the optimal incubation conditions for any assay system targeted to a given analyte concentration, P, at which the standard deviation of assay results is to be minimized. Estimates of both the content of binding sites and the equilibrium constant, K, of the specific binding agent are necessary, and these can be derived from Scatchard plots. For six RIA systems, of which three were one-step and three were two-step assays, experimental assay conditions and precision data were compared with theoretical predictions. Experimentally determined antibody binding site concentrations agreed fairly well with those independently evaluated by mathematical optimization. Mean precision indices, defined as constituting an average over the complete precision profile, were found to be within the theoretically predicted range, i.e. two- to threefold the pipetting error.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites, Antibody↗

PubMed1991

[Acceptance of corpus cavernosum auto-injection therapy in long-term treatment of erectile dysfunction].

A total of 121 patients suffering from erectile dysfunction were evaluated by means of a questionnaire. In all these cases corpus cavernosum autoinjection therapy had been recommended. The aim of the study was to determine the acceptance and complications of the therapy, general level of satisfaction with it, and reasons for refusal. Completed questionnaire were received from 89 patients (75.5%), 56.2% of whom had applied the therapy continuously, while 18% had broken it off and 25.8% had never started on therapy (cumulative dropout rate 43.8%). The complications encountered were temporary hematomas (25.8) and deviations of the penis (10.1%). In 6.1% indurations of the penis were found. The frequency of prolonged erection needing an antidote was 0.07% in the continuous treatment group. The relatively high drop-out rate in the autoinjection therapy group shows the necessity for intensive patient care and the need for alternative therapy options and a more critical view of reports already published of success with autoinjection therapy.

Erectile Dysfunction↗

PubMed1991

[Production of monoclonal antibodies in serum-free medium in dialysis tubing].

A simple procedure for the production of pure monoclonal antibodies (mab) in dialysis tubing has been used. Hybridomas which produce pancreatic islet cell reactive monoclonal antibodies were grown in dialysis tubing containing serum free medium. The dialysis tubing was inserted into a flask with medium containing 7.5% foetal calf serum. The flask was placed on a roller and medium was changed every two days. The optimal time for harvesting the mab could be shown to be after 10 days of culture with a 4 fold increased immunoglobulin concentration in comparison to a conventional hybridoma culture. Immunoglobulin concentrations up to 110 mg/l and cell yields of 1.3 x 10(6)/ml have been obtained. The low concentration of contaminating low molecular weight proteins in the supernatant facilitated or saved purification of mab.

Animals↗

PubMed1991

[Piezoelectric extracorporeal lithotripsy in children. Assessment over 3 years].

From 1987 to 1990, 45 children whose age ranged from 5 months to 14 years and who presented with urinary lithiasis underwent piezoelectrical extracorporeal lithotripsy with a Piezolith 2,300 and 2,500 system. We were able to perform the treatment without anesthesia in 53% of the children. The results were highly encouraging as, and without any severe complication; 84% of the children had no residual calculus after 3 months.

Adolescent↗

PubMed1991

CELISA for rapid screening of monoclonal islet cell surface antibodies using living rat insulinoma cells as target.

An improved rapid cell enzyme-linked immunosorbent assay (CELISA) is described which is suitable for the large scale screening of monoclonal antibodies to islet cell surface antigens. 5 x 10(4) insulin-producing rat insulinoma (RIN) cells were seeded per well in a 96-well flat-bottomed polystyrene plate coated one day before a 0.01% poly-D-lysine solution in PBS. After culture for 4 days in 200 microliters/well RPMI 1640 supplemented with 7.5% heat-inactivated fetal calf serum, the cell number per well was up to 2.1 x 10(5). These monolayer RIN cell cultures were used as a target for the detection of islet cell surface antibodies (ICSA) in the supernatants of hybridomas. The cells were used without fixation to avoid modification of sensitive surface antigens. Poly-D-lysine did not cause non-specific binding of immunoglobulins to the plastic wells as tested with irrelevant monoclonals. The specificity and sensitivity of the method is comparable to indirect immunofluorescence. All mc-ICSA primary screened by indirect immunofluorescence using viable RIN cell suspensions were positive in this CELISA. There was a correlation (r = 0.7; n = 44) between the antibody binding measured by CELISA and the indirect immunofluorescence technique. The advantage of this CELISA is that cell surface structures are well preserved in a viable cell monolayer used as target without chemical fixation. This assay procedure should be generally suitable for the initial screening of monoclonal antibodies to cell surface antigens of cells growing under culture conditions.

Animals↗

PubMed1991

Different multiple reactivity of monoclonal islet cell binding antibodies using indirect immunofluorescence technique on viable cells or cellular ELISA on desiccated cells as target.

Two commonly used methods for screening hybridoma supernatants secreting monoclonal islet cell reactive antibodies (mc-ICRA) were performed to investigate the specificity of the monoclonals established. For this, endothelial, neuroblastoma, murine subcutis and two myeloma cell lines were used as targets in comparison to the insulin-producing rat insulinoma cell line (RIN), either immobilized and permeabilized in cellular enzyme linked immunosorbent assay (CELISA) or in suspension of viable cells in the indirect immunofluorescence test. In addition, rat splenocytes were used for estimating multireactivity of mc-ICRA in ELISA. Using permeabilized target cells, we obtained a high multireactivity of the monoclonal antibodies (mab) tested, indicating a high incidence of molecular mimicry between cytoplasmic antigens of different cell lines. In contrast to CELISA, if only cell surface antigens of viable cells are accessible, detected by the immunofluorescence technique, the high multireactivity is not observed. For investigating the specificity of monoclonals, the complexity of target antigens used must be taken into consideration.

Animals↗

PubMed1991

[Alloplastic ureter substitution and limitations in clinical application. A status analysis].

Operative ureteral replacement with the patient's own body tissue or by reconstructive ureteral surgery is indicated relatively often. The operative methods applied vary: they include pelvic flap pyeloplasty, caudal transposition of the kidney, interposition of the small intestine, trans-ureterostomy, calico-ureterostomy, of bladder flap transplantation and autotransplantation of the kidney. When the indications are correctly observed with reference to the kind and location of the ureteral lesion all these methods are successful. The methods of alloplastic replacement of the ureter, in contrast, have lost clinical importance and should be performed only in rare, isolated cases, mainly as a short-term solution. Possible indications are a poor general condition in patients for whom alloplastic ureteral replacement is the only alternative to permanent nephrostomy and malignant tumours requiring immediate irradiation, which cannot be postponed until definitive wound healing has taken place following a plastic operation. It is important that problems of biocompatibility have now been largely overcome. Segmental ureteral replacement with alloplastic materials is not possible, however, and the functional difficulties with urinary transport have not been solved in the long term, even in models with pumps and reflux-preventing mechanisms.

Biocompatible Materials↗

PubMed1991

[Complexity-oriented surgical strategies in vesicovaginal fistulas].

Since 1975 a total of 55 patients with vesicovaginal fistulas have undergone surgery at the Clinic of Urology, University of Saarland, Homburg/Saar. A majority (55%) of the cases were complicated. In 9 cases supravesical urinary diversion was necessary. Successful closure of the fistula was achieved in 45 patients (81.8%); only in one case is the fistula still present. In 5 patients with uncomplicated fistulas successful closure was accomplished by a vaginal approach. In the presence of complications, e.g., previous radiotherapy or accompanying lesions of the ureter or rectum, a transvesical/transabdominal approach was preferred; surgery was successful in 93.3% of such cases.

Adolescent↗

PubMed1991

[Enzyme immunoassay for the determination of albumin in urine].

Two modifications of a double antibody enzyme immunoassay for the determination of urinary albumin content are described. The method is simple, rapid and precise and can be carried out in test tubes and on microtiter plates as well. In 1:10 diluted urine samples albumin concentrations of 1.25 to 20 mg/l (corresponding to the normal range) can be determined. For a control sample with 0.3 mg/l albumin the intra- and interassay coefficients of variation were 4.9% (n = 11) and 10.4% (n = 21), respectively, on microtiter plates.

Albuminuria↗