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M Wirth

Publications and source records attributed to M Wirth.

At least 73 records · Page 4Linked to original sources
PubMed1997

Ribonuclease T1 has different dimensions in the thermally and chemically denatured states: a dynamic light scattering study.

Ribonuclease T1 can be unfolded and refolded without forming noticeable amounts of aggregates allowing to characterise the dimensions of a protein in different denatured states in terms of the Stokes radius RS. Upon thermal unfolding RS increases from 1.74 nm at 20 degrees C to 2.14 nm at 60 degrees C. By contrast, RS = 2.40 nm was obtained at 5.3 M guanidinium chloride (GuHCl) and 20 degrees C. Heating from 20 degrees C to 70 degrees C in the presence of 5.3 M GuHCl led to a 5% decrease in RS.

Escherichia coli↗
PubMed1997

[Value of PSA density determination in prostate carcinoma].

The PSA density was calculated in 98 patients with carcinoma of the prostate by using the weight and/or volume of the radical prostatectomy specimen. In 22 of 98 patients, PSA serum levels ranged between 4 and 10 ng/ml. Eleven patients showed PSA serum levels below 4 ng/ml and 65 patients above 10 ng/ml. Sixty-one of the 65 patients with PSA serum levels > 10 ng/ml had PSAD values above 0.15, and we therefore suspected the presence of carcinoma of the prostate according to Benson et al. Twelve of the 22 patients with PSA serum levels between 4 and 10 ng/ml had PSAD values below the cut-off value of 0.15. In addition, all 11 patients with PSA values < 4 ng/ml showed PSAD values < 0.15, a range that can be regarded as almost harmless according to Benson et al. In conclusion, it seems apparent that in patients with PSA serum levels < 10 ng/ml, no important additional information is obtained from the PSAD determination. Routine measurement of PSAD for evaluating the risk of carcinoma of the prostate in individual cases can therefore not be recommended.

Adult↗
PubMed1997

[Primary renal plasmacytoma. A case report].

We describe a patient with a primary renal plasmacytoma. In the literature available, only six clinical cases have been reported. A 64-year-old patient is presented who had the clinical signs of a renal cell carcinoma. Histological examination after nephrectomy, however, revealed a plasmacytoma. Based on this case, we discuss how one should proceed in this disease. Primary renal plasmacytoma can be tentatively diagnosed preoperatively only in the presence of paraproteinemia or Bence-Jones proteinuria, as it cannot be distinguished from other renal tumors by imaging procedures. Postoperatively, further staging procedures must rule out bone involvement (solitary myeloma or multiple myeloma). Nephrectomy is required in patients with plasmacytoma only if renal complications occur.

Carcinoma, Renal Cell↗
PubMed1997

The ratio of formation of prostacyclin/thromboxane A2 in HUVEC decreased in each subsequent passage.

In this study, we analyzed the antioxidative potential (SOD-, GSH-Px-activity) and the basal, H2O2- and ATP-stimulated formation of PGI2 and TXA2 in human umbilical vein endothelial cells (HUVEC) of different passages. The subcultivation of cells partly represents the process of aging. Both subcultivation of the cells and the H2O2 incubation did not significantly influence the activity of SOD and GSH-Px. H2O2 (0.1 mM and 1.0 mM) stimulated the generation of PGI2 and TXA2 in the cell passages time dependently. The formation ratio of PGI/TXA2 changed from 640:1 (0.1 mM H2O2) or 430:1 (1.0 mM H2O2, 40 min incubation) at the 1st passage, to 13:1 and 17:1, respectively, at the 4th passage. This resulted from the reduction of the PGI2 synthesis connected with more pronounced TXA2 formation. The same behavior was found in the basal and ATP-stimulated eicosanoid formation. Based on this, the age-dependent activation of the oxygen radical formation could be responsible for the modified eicosanoid metabolism resulting in vascular complications in the elderly.

Adenosine Triphosphate↗
PubMed1997

A sensitive method for the detection of murine C-type retroviruses.

A RT-PCR assay was developed for group-specific detection of murine C-type retroviruses using a nested set of degenerated primers. To distinguish exogenous viruses from related, but silent endogenous viruses, a DNAse I pretreatment of supernatants is applied. This is followed by a heat inactivation/denaturation step. The PCR method is ultrasensitive. which enables the detection of 100 attogram of MoMuLV proviral DNA or up to 1-10 infectious mouse C-type retroviruses in 10 microl supernatant of infected cells. The high specificity of the method allows the differentiation between mouse C-type retroviruses and related retroviruses of the A, B, and D type and C-type retroviruses found in other species. It serves as a valuable tool for the screening of animal cell cultures for contaminations with mouse retroviruses, e.g. hybridomas or recombinant cell lines producing foreign proteins.

3T3 Cells↗
PubMed1997

Influence of long-term supplementation with alpha-linolenic acid on myocardial lipid peroxidation and antioxidative capacity in spontaneously hypertensive rats.

The ischaemic vulnerability of the heart of spontaneously hypertensive rats (SHR) is enhanced after feeding an alpha-linolenic acid (LNA) enriched diet. Because oxygen radical-induced reactions (e.g. lipid peroxidation) are involved in the ischaemic damage, an increased susceptibility of the SHR heart to such damaging reactions might be the reason. As a sign of the enhanced susceptibility to lipid peroxidation of LNA-fed SHR, we found (measured as TBARS) higher plasma and heart lipid peroxide levels (3.84 +/- 0.50 micromol/l vs 2.98 +/- 0.78 micromol/l and 507 +/- 127 nmol/g prot. vs 215 +/- 80 nmol/g prot., respectively) after feeding LNA. Using Fe2+/Vit. C to induce lipid peroxidation in myocardial tissue homogenates, we demonstrated the enhanced susceptibility to lipid peroxidation of the LNA-fed SHR heart (68 +/- 12 nmol/min x g prot. vs 40 +/- 8 nmol/min x g prot.) also in vitro. The myocardial enrichment of n-3 polyunsaturated fatty acids (PUFA) resulting in a higher peroxidation index (PI 227 vs. 170) and the loss in myocardial activities of the antioxidative enzymes (SOD: 76 +/- 24 U x 10(3)/g prot. vs 235 +/- 150 U x 10(3)/g prot.; GSH-Px: 32 +/- 5 U/g prot. vs 110 +/- 30 U/g prot.) by feeding LNA could be the cause of the increase in myocardial susceptibility to lipid peroxidation of PUFA supplemented SHR.

Animals↗
PubMed1996

Heterogeneity of cerebral hemodynamics and metabolism in carotid artery disease.

METHODS: Eight patients with severe unilateral carotid stenosis (> 70%) were evaluated using PET to assess parametric changes in cerebral blood flow, blood volume, metabolic rate for oxygen, metabolic rate for glucose, oxygen extraction fraction and glucose extraction fraction. We performed these examinations because clinical history and physical exam results suggested possible cerebral vascular disease. Four patients were neurologically asymptomatic with other signs of peripheral vascular disease (e.g., episodic vertigo, TIA and claudication). All patients had normal neurologic examinations and normal CT or MRI studies. PET images were analyzed by two methods. First, regions of interest were used for the entire hemisphere, vascular territories and borderzones. Regions ipsilateral to the carotid stenosis were compared to respective regions in the contralateral hemisphere using Student's t-test. Second, visual inspection of each image was performed. RESULTS: Statistical analysis demonstrated no significant differences between hemodynamic and metabolic parameters for regions ipsilateral to the carotid stenosis and contralateral homotopic reference regions. Upon visual examination, however, all patients had focal changes in either cerebral blood flow, blood volume, glucose extraction fraction and/or oxygen extraction fraction. CONCLUSION: Visual inspection is important in the evaluation of pathophysiological changes caused by unilateral carotid stenosis. Clinical decisions in patients with carotid artery disease should be based on careful visual examinations and statistical analyses of appropriately selected regions.

Brain↗
PubMed1995

Calorimetric investigation of thermal stability and ligand-binding characteristics of disulfide-bond-cleaved ribonuclease T1.

A combination of differential titration calorimetry and differential scanning calorimetry was used to study the effect of disulfide bond cleavage and reaction with iodoacetamide of ribonuclease T1 on both the binding of nucleotides and the thermal stability of the free enzyme species. Although guanosine monophosphates still bind to the active site of the modified protein the transition temperature of unfolding and the transition enthalpy decrease drastically indicating a relatively loose structure. The calorimetric data presented in this study suggest a cooperative linkage between the site of the disulfide bonds, the ligand-binding site, and the general thermodynamic stability of the enzyme.

Calorimetry, Differential Scanning↗
PubMed1995

Effects of adding various oils to the diet on growth, feed conversion and chemical composition of carp (Cyprinus carpio).

The suitability of various vegetable and fish oils was tested as feed components for one-summer-old carp fingerlings. Five diets were used: a basal diet, which served as control feed, was supplemented with 10% corn-germ oil, 10% sunflower oil, 10% fish oil or 10% rapeseed oil, respectively. By means of the lipid supplementation the crude protein content decreased from 35.5% in the basal diet to 31.9% in the test diets, whereas the gross energy level increased from 16.3 to 18.9 MJ/kg. The diets were fed over a period of 84 feeding days and water temperature was 23 degrees C. Weight gain, feed conversion ratio and protein utilization were superior in all groups of carp which received the fat-enriched high energy diets. Considering the gain in % of the initial weight, the control fish reached less than 400% whereas all carp in the test groups, which consumed the oil-enriched diets, reached 455 to 485%. A significant influence of the kind of lipid on growth and feed conversion could not be recognized. The lipid-enriched diets with higher energy content resulted in increased fat levels of the carp. Fatty acid composition of the carp reflected that of the diets. In the control group and the fish oil group the levels of palmitic, palmitoleic, eicosapentaenoic and docosahexaenoic acid were especially high corresponding to the fatty acid profile of the diets. In carp fed the diets supplied with corn-germ oil and sunflower oil linoleic acid was dominant whereas the carp fed the rapeseed diet were characterized by a high level of oleic acid.

Aging↗
PubMed1995

Malignant neurofibroma of the urinary bladder.

We report a case of a large malignant neurofibroma of the urinary bladder occurring in a 33-year-old patient with Recklinghausen's neurofibromatosis. Urologic manifestations of neurofibromatosis are infrequent; a neurofibroma of the bladder with malignant degeneration is an extreme rarity. To date only 3 cases have been described in the literature.

Adult↗
PubMed1995

[Results of 15 years of radical prostatectomy].

From July 1969 to May 1994, radical prostatectomy was performed in 630 patients with clinically localized prostate cancer at the Department of Urology, University of Würzburg Medical School. These included 74 patients subsequently followed up for 15 years or more 15 years (15-23 years, mean 17.5 years), who were the subjects of the present study. Of these 74 patients 59 had pT2 tumors and 10 had pT3 tumors according to the staging criteria of the 1992 edition of the UICC TNM classification. The remaining 5 patients had microscopic lymph node metastases detected at staging pelvic lymphadenectomy (stage pT2-3pN1-2). Patients with lymph node involvement were treated by immediate orchiectomy. All other patients received no further treatment until progression occurred. The overall 15-year survival rate actually observed the 74 patients was 50% (37/74) and the disease-free survival rate was 43.2% (32/74 pts). Stage-related overall and disease-free survival rates were found to be 54.2% and 49.1%, respectively, for patients with pT2 tumors, 40% and 30% for those with pT3 tumors, and 20% and 0 for patients with lymph node metastases. Progression (either local recurrence or distant metastatic spread) was noted in 22 of the 74 patients (29.7%) within the 15-year period following radical prostatectomy. Mean time to progression was 7.9 years (3 months to 17 years). Within the follow-up period, 17 patients (23%) died of prostate cancer. These actual 15-year follow-up data show radical prostatectomy to be the most effective means of achieving long-term disease-free survival, if not cure, in patients with clinically localized prostate cancer.

Adult↗
PubMed1994

Expression of recombinant antibody and secreted alkaline phosphatase in mammalian cells. Influence of cell line and culture system upon production kinetics.

The growth and productivity of an Sp2/0 cell line, F3b10, expressing a recombinant antibody (rAb) and BHK21 cells expressing either the same rAb from the same plasmids (BHK.IgG) or secreted alkaline phosphatase (SEAP) (BHK.SEAP) were investigated. The F3b10 line was grown as a single cell suspension. The BHK lines were grown either as suspended natural aggregates or on Cytodex 3 microcarriers. The data for F3b10 showed that the cell-specific rAb production rate (QsrAb) increased in parallel with increases in the specific growth rate (mu). A similar result was obtained for suspended aggregate cultures of both recombinant BHK cell lines. In contrast, for microcarrier cultures of both BHK cell lines, Qsproduct increased as mu decreased. This report shows that the relationship between cell growth and Qsproduct for the cell lines and products studied is dependent upon the culture process. In systems where recombinant cells are growing as a single cell suspension or within a natural suspension aggregrate, Qsproduct increased with increases in mu. In such systems, the cells have a rounded morphology. When cells were grown on microcarriers. Qsproduct decreased as mu increased. Cells growing attached to a surface are flat and elongated. The observed differences in the relationship of Qsproduct to mu are correlated with changes in cell morphology. The relationship between Qsproduct and mu is also affected by the choice of cell line.

Alkaline Phosphatase↗
PubMed1994

Detection of mycoplasma contaminations by the polymerase chain reaction.

The polymerase chain reaction (PCR) has been used for the general detection of Mollicutes. 25 Mycoplasma and Acholeplasma species were detected including important contaminants of cell cultures such as M. orale, M. arginini, M. hyorhinis, M. fermentans, A. laidlawii and additional human and animal mycoplasmas. PCR reactions were performed using a set of nested primers defined from conserved regions of the 16S rRNA gene. The detection limit was determined to be 1 fg mycoplasma DNA, which is equivalent to 1-2 genome copies of the 16S rRNA coding region. The identity of the amplification products was confirmed by agarose gel electrophoresis and restriction enzyme analysis. DNA from closely and distantly related micro-organisms did not give rise to specific amplification products. The method presented here offers a much more sensitive, specific and rapid assay for the detection of mycoplasmas than the existing ones.

Base Sequence↗
PubMed1994

Screening retroviral packaging cells for highly efficient virus production by using a combined selection procedure.

To facilitate the screening for clones of transfected packaging cells producing a high yield of recombinant retrovirus, we present a fast and simple method for the isolation of overexpressing cells. By this method the efficiency of virus production can generally be enhanced 10- to 100-fold by application of high selection pressure. Cell lines which exhibit titers of up to 10(8) CFU/ml were obtained.

3T3 Cells↗
PubMed1994

Are auxiliary methods necessary prior to ESWL in patients with a solitary kidney?

Between January 1985 and October 1991, 54 patients with calculi in a solitary kidney were treated by ESWL using the Dornier HM-3 lithotriptor. The mean age of the patients was 53.9 years (range 24-77 years). In 51.9% of the cases the stones measured > 1 cm in diameter, in 42.6% between 0.4 and 1 cm, and in 5.5% < 0.4 cm in diameter. In 39 of the 54 patients (72.2%) the calculi could be disintegrated by a single ESWL treatment. In 12 patients (22.2%) 2 ESWL treatments were necessary, and another 3 patients (5.6%) needed 3 ESWL treatments. In 6 cases (11.1%) percutaneous nephrostomy (PCN) was needed, and in 8 other patients ureteric stents were inserted prior to ESWL because of obstruction of the upper urinary tract, causing impending urosepsis in 8 of these 14 cases. Following ESWL, PCN was performed in 4 cases (7.4%) and a ureteric stent was inserted in 2 patients (3.7%) because of urinary obstruction. At discharge from the hospital 15 of the 54 patients (27.8%) were stone-free and 34 patients (63.0%) had small residual fragments of < 0.4 cm in diameter. One year after treatment, 42 patients could be evaluated at a control examination. 37 of these 42 patients (88.1%) were stone-free and 3 patients (7.1%) showed residual fragments of < 0.4 cm. In conclusion, our results demonstrate that, if there is no ureteric obstruction present prior to ESWL, the majority of patients with a solitary kidney do not present extraordinary problems and do not need auxiliary procedures.

Adult↗
PubMed1994

Radical prostatectomy in patients with incidental prostate carcinoma.

Radical prostatectomy was carried out in 30 patients with an incidental carcinoma of the prostate. A tumor stage T1a (A1) was present in 7 cases and a tumor stage T1b (A2) in 23 cases. None of the 30 patients died postoperatively. As intraoperative complication, a rectum perforation occurred in 1 case. In the 23 patients with a T1b tumor, a pT2pN0M0 lesion was found in 10 cases and pT3pN0M0 lesion in 11 cases on pathohistological examination after radical prostatectomy. In 5 out of 30 patients the carcinoma could no longer be detected in the radical prostatectomy specimen. In 1 patient with a T1a tumor, pelvic lymphadenectomy revealed a single lymph node metastasis. Tumor progression did not occur in any of the 7 patients with a T1a tumor after an observation period of 9 months up to 16 years (average 4.6 years). The percentage of progression-free patients in stage T1b was calculated as 81.4% 10 years after surgery. The calculated overall survival time of patients in stage T1b was 76.3% after 10 years and the tumor-related survival was 87.5%.

Actuarial Analysis↗
PubMed1993

Specificity and sensitivity of polymerase chain reaction (PCR) in comparison with other methods for the detection of mycoplasma contamination in cell lines.

The polymerase chain reaction (PCR) amplification was used for the detection of mycoplasma contamination in 42 continuous cell lines. Using the microbiological cultivation on agar as the reference method, 29 cell lines were regarded as positive and 13 cell lines as negative. The double-step PCR analysis employed nested primers that anneal to gene sequences coding for the evolutionarily conserved 16 S rRNA of some 25 different mycoplasma species (including the ones most commonly found in cell cultures). In terms of the positivity or negativity of mycoplasma infection the results were identical for the agar assay and PCR amplification. All positive cell lines displayed distinct, unequivocal, objectively discernible bands on agarose gels while the non-infected specimens showed no DNA amplification. A simultaneously performed comparison with four other commonly used detection methods (DNA-RNA hybridization in solution, DAPI DNA fluorescence staining, immunostaining with a monoclonal antibody and an ELISA) showed that PCR produced significantly less false-negative or false-positive results than all the other methods. Furthermore, in dilution experiments, PCR correctly detected the infecting mycoplasmas at the lowest level of 1/10(4) whereas the other assays were less sensitive. It is concluded that double-step PCR employing nested primers is superior to other mycoplasma detection methods in many respects: simplicity and speed, high specificity and extreme sensitivity, objectivity and accuracy.

Animals↗