PubMed Health⌕ Search

Biomedical subjects

A Müller

Publications and source records attributed to A Müller.

At least 271 records · Page 15Linked to original sources
PubMed1998

[Diagnosis of liver tumors--what is necessary for therapy planning?].

For the surgical treatment of liver tumors, two initial steps are necessary: functional operability must be proven and oncological and local inoperability must be ruled out. The diagnostic process consists of a series of steps, beginning with non-invasive procedures such as laboratory findings and sonography, continuing with CT, CTAP, laparoscopy in the case of hepatic cirrhosis, up to explorative laparotomy. The potential operability is re-checked after each step. Punction, MRI and scintigraphy are implemented in special cases. The early implementation of MRI is of particular value for the diagnosis of certain benign processes.

Diagnostic Imaging↗
PubMed1998

[Imported hepatozoonosis in the dog: 3 cases].

Canine hepatozoonosis is presented with 3 cases. The most common signs are: fever, anorexia, weight loss, diarrhea and vomiting, muscle weakness, lymphadenopathy, anemia and purulent discharge from the nose and the eyes. Because an infection with H. canis in the dog is often associated with other infectious diseases such as leishmaniasis, ehrlichiosis and babesiosis, the clinical picture may be dominated by these diseases. The diagnosis is made with the typical inclusions in neutrophilic granulocytes and monocytes. Only short remissions may be obtained with the presently available medications.

Animals↗
PubMed1998

Polymerase chain reaction for diagnosis and species differentiation of microsporidia.

Polymerase chain reaction (PCR) techniques have been developed for the detection of microsporidian DNA in different biological samples. We used sequence data of the rRNA gene for the identification of Enterocytozoon bieneusi, Encephalitozoon intestinalis, E. cuniculi, and E. hellem in different biological samples of HIV-infected patients by PCR, Southern blot hybridization, restriction endonuclease digestion analysis, cloning, and comparative genetic sequencing. One primer pair was used for amplification of the entire small subunit (SSU)-rRNA gene of E. bieneusi, E. intestinalis, and E. hellem from samples with electron microscopy confirmed infection. The amplified 1.2 kb SSU-rRNA gene fragments were ligated into a pMOSBlue T-vector, transfected into pMOSBlue competent cells, and were used as positive controls. Several primer pairs and hybridization probes were used to amplify and identify microsporidian DNA from different samples. Light microscopical examination of samples was performed in all patients and transmission electron microscopy was done on a subset of patient samples. DNA products were obtained from all samples with confirmed microsporidial infections. The identity of the DNA fragments was determined by Southern blot hybridization or by restriction endonuclease digestion analysis or by DNA sequencing. The results show that PCR is a reliable and sensitive indicator for the presence of microsporidian DNA in different biological samples of HIV-infected patients. PCR can be used further for species differentiation of microsporidia, even between species which cannot be differentiated by light and/or electron microscopy.

Animals↗
PubMed1998

Assessment of acute mountain sickness by different score protocols in the Swiss Alps.

INTRODUCTION: Purpose of the present study was to evaluate the Lake Louise acute mountain sickness (AMS) score questionnaire at different altitudes and to compare it with the currently used clinical score and the environmental symptoms questionnaire AMS-C score. METHODS: We investigated 490 climbers who stayed over night at 4 huts in the Swiss Alps, located at the altitudes of 2850 m, 3050 m, 3650 m, and 4559 m. AMS was assessed using our previously described clinical score, the Lake Louise consensus AMS score questionnaire and the environmental symptoms questionnaire III. RESULTS: Below 4000 m, the prevalence of AMS, defined by symptoms that force a reduction in activity, was 7%; when assessed with the clinical score (score > or = 3) it was 22%; with the AMS-C score (score > or = 0.7) 4% and with the Lake Louise score (score > 4) 8%. At the altitude of 4559 m, the prevalence of AMS was 30%, 38%, 40%, and 39%, respectively. The standardized regression coefficients from multiple regression analysis (adjusted R2 0.65, p < 0.001) were 0.45 (p < 0.001) for the self-reported Lake Louise score, 0.48 (p < 0.001) for the sum of the points assigned in the clinical section of the Lake Louise questionnaire, and 0.05 (p = 0.27) for the AMS-C score. The sensitivity and specificity of the Lake Louise score > 4 was 78% and 93%, respectively. CONCLUSIONS: The Lake Louise consensus score is adequate and, compared with the AMS-C score, more effective for the assessment of acute altitude illness at different altitudes.

Acute Disease↗
PubMed1998

[Minimal invasive, percutaneous ventriculostomy in therapy of severe craniocerebral trauma].

From May 1996 until April 1997 percutaneous CT-controlled ventriculostomy (PCV) was performed in 19 patients with severe traumatic brain injury and no indication for decompressive craniotomy. There was a significant reduction in the duration of the procedure compared to burr-hole ventriculostomy with no complications. Because of further advantage of PCV CT-controlling is the possibility of puncturing even very narrow ventricles.

Brain Edema↗
PubMed1998

[Value of diagnostic laparoscopy in primary malignant liver tumors].

The advent of new imaging modalities such as CT-AP and MRT has markedly improved the diagnosis and staging of primary liver tumors and will change the diagnostic impact of laparoscopy. Diagnostic laparoscopy in this retrospective study was not found to add information in regard to tumor staging and resectability, and there was no clear benefit by avoiding diagnostic laparotomies when all imaging and biopsy techniques available were used preoperatively. Therefore, we advocate the use of diagnostic laparoscopy only in selected cases suspicious for superficial small tumor lesions and cirrhosis with impact on the treatment modality.

Adult↗
PubMed1997

A comparative study of two levonorgestrel-containing hormone replacement therapy regimens of efficacy and tolerability variables.

OBJECTIVE: To compare the effect of two sequential hormone replacement regimens differing in the dose of levonorgestrel on climacteric symptoms, bleeding pattern and lipid metabolism in postmenopausal women. STUDY DESIGN: In a multicentre, randomized, double-blind, active-treatment-controlled study, 210 postmenopausal women were assessed at the end of treatment cycles 3 and 6. The high-levonorgestrel group was treated with 2 mg estradiol valerate (days 1-21) sequentially combined with 0.25 mg levonorgestrel (days 12-21). The low-levonorgestrel group received the same estrogen regimen (2 mg estradiol valerate, days 1-21), but levonorgestrel was administered sequentially in a dose of 0.15 mg during the last 12 days of the cycle (days 10-21). Statistical analysis by Student's t-test for dependent variables (measured values versus baseline) and independent variables (differences between groups), and the composite t-test method for comparison of both regimens with respect to efficacy, was performed. RESULTS: Both groups were statistically comparable. The trial was completed by 137 subjects. Protocol violations occurred in 38 cases. Thirty-five subjects dropped out during the study, 21 of them because of adverse events. Both treatments were equally effective in the treatment of climacteric complaints. There were no clinically significant changes in body weight, blood pressure, haematological tests, and parameters of clinical chemistry. There was a tendency towards a reduction in bleeding intensity in both groups in the second half of the treatment period. The treatment for six cycles with both regimens significantly (P < 0.05) decreased plasma concentrations of triglycerides (significant in the low-levonorgestrel group only), high-density lipoprotein cholesterol, high-density lipoprotein-3-cholesterol, lipoprotein(a) and apolipoprotein A1. In parallel, the serum concentration of total cholesterol increased significantly in both treatment groups, whereas low-density lipoprotein cholesterol increased significantly in the high-levonorgestrel group only. The changes in high-density lipoprotein-2-cholesterol, and apolipoprotein B did not reach statistical significance. CONCLUSIONS: It can be concluded that both sequential combined oral hormone replacement therapy (HRT) regimens were equivalent with respect to efficacy and tolerability in the treatment of women with climacteric complaints. The preparation with the lower dose of progestin showed a tendency towards a less unfavourable influence on the lipid profile.

Cohort Studies↗
PubMed1997

Anti-CD4 monoclonal antibody-induced allograft tolerance in rats despite persistence of donor-reactive T cells.

Although CD4-targeted therapy abrogates acute rejection and may induce permanent graft acceptance in rodents, little is known about the mechanisms of long-term graft survival in these models. Recently, we have shown that treatment with a nondepleting anti-CD4 monoclonal antibody (mAb) (RIB-5/2) induces long-term survival of renal, heart, and skin allografts in strong major histocompatibility complex I/II incompatible rat strains. Here, we demonstrate that the development of major histocompatibility complex-specific and tissue-nonspecific tolerance rather than graft adaptation is responsible for long-term anti-CD4 mAb-induced transplant survival. Donor-specific but not third-party heart and pancreatic islet grafts were accepted permanently without adjunctive therapy in long-term kidney allograft recipients, and infusion of naive or alloimmune splenocytes failed to break the tolerant state. Interestingly, alloreactive T cells were not depleted in these long-term survivors, as ex vivo donor-specific mixed lymphocyte reaction was largely unaffected. The reverse transcriptase-polymerase chain reaction analyses of long-term renal allografts before and after donor-specific antigen challenge revealed no changes in CD3 mRNA level, but showed up-regulation of CD25, interleukin (IL) 2, interferon (IFN) gamma, IL-4, and IL-10 mRNA in the early phase, suggesting the presence of alloreactive T cells in tolerant rats. At later time points, the expression of IFN-gamma declined rapidly, whereas IL-4 persisted, resulting in a reversal of IFN-gamma/IL-4 ratio. Our data demonstrate the stability of anti-CD4 mAb-induced tolerance despite persistence of alloreactive T cells, suggesting the role of active tolerance-maintaining mechanisms. The T helper (Th) 1/Th2 shift may be involved in this regulatory process, as anti-CD4 mAb prevents acute graft-deteriorating rejection by effectively blocking Th1 responses, and well-functioning grafts may tolerize themselves by inducing regulatory cells.

Animals↗
PubMed1997

Interleukin-6, soluble interleukin-2-receptor and soluble interleukin-6-receptor in sera of patients with rheumatoid arthritis: influences of disease activity and drug therapy.

Cytokines and their receptors play a fundamental role in the development and maintenance of the inflammatory process in rheumatoid arthritis (RA). The purpose of this study was to evaluate sIL-2R, sIL-6R and IL-6 levels in the sera of 48 RA patients and to correlate them with disease activity, indicators of inflammatory process as ESR and CRP, and drug treatment modalities. IL-6 and sIL-2R levels were positively correlated with disease activity, ESR and CRP. No correlation between sIL-6R levels and these markers were observed. Our results suggest that different drug therapies have a decisive influence on the levels of selected cytokines. All investigated disease-modifying antirheumatic drugs (DMARDs) were able to reduce the IL-6 level significantly. Non-immunosuppressive DMARDs decreased the amount of circulating sIL-2R more than immunosuppressive drugs. Treatment with methotrexate resulted in a significant reduction of circulating levels of sIL-6R compared to azathioprine therapy. Under low dose glucocorticoid therapy, significantly lower levels of sIL-6R were found than in patients without glucocorticoids. In conclusion, the results provide some arguments in favour of combined drug therapies, which might possibly enhance the effectiveness of RA therapy.

Adult↗
PubMed1997

Increase in gap junction conductance by an antiarrhythmic peptide.

Impaired cellular coupling is thought to be a very important factor for the genesis of cardiac arrhythmia. Cellular coupling is mediated by gap junctions. However, there are no therapeutic agents or experimental substances yet that increase cellular coupling. In addition, it has been shown that most antiarrhythmic drugs available now possess serious adverse effects. Thus, there is an urgent need for new antiarrhythmic agents. Previous studies using epicardial mapping in isolated rabbit hearts provided indirect evidence supporting the hypothesis that a newly synthesised antiarrhythmic peptide (Gly-Ala-Gly-4Hyp-Pro-Tyr-CONH2 = AAP10) might act via an increase in cellular, i.e., gap junctional coupling. The aim of the present study was to test this hypothesis. Measurement of the stimulus-response interval in papillary muscle showed a decrease of about 10% after application of 1 microM AAP10. These results are compatible with the hypothesis of AAP10 acting on gap junctions. In order to prove this hypothesis, gap junction conductance was measured directly by performing double-cell voltage-clamp experiments in isolated pairs of guinea-pig myocytes. During a 10 min control period gap junction conductance slowly decreased with a rate of -2.5 +/- 2.0 nS/min. After application of 10 nM AAP10 this behaviour reversed and gap junction conductance now increased with +1.0 +/- 0.7 nS/min. Upon washout of AAP10 gap junction conductance again decreased with a rate similar to that under control conditions. Another important finding was that we could not detect any other actions of AAP10 on cardiac myocytes. All parameters of the transmembrane action potential remained unchanged and, similarly, no changes in the IV relationship of single cardiac myocytes treated with 10 nM AAP10 could be observed. We conclude that AAP10 increases gap junction conductance, i.e., cellular coupling in the heart. This finding might be the first step towards the development of a new class of antiarrhythmic agents.

Animals↗
PubMed1997

Conversion of biocytin labelled cells and structures for the confocal laser-scanning method.

The method for converting biocytin preparations of brain sections fills a gap in the application of confocal laser-scanning microscopy. Both neuronal and non-neuronal structures are converted. The background remains free of staining. The protocol can be applied to old and already existing biocytin-(diaminobenzidine)-nickel preparations which are then made accessible to evaluation with the laser-scanning microscope by the substitution of nickel with silver-gold. Sodium thiosulphate is used to remove the unbound silver. The reflection image of the laser-scanning microscopy provides more information than the transmission image.

Animals↗
PubMed1997

The application of various protic acids in the extraction of (1-->3)-beta-D-glucan from Saccharomyces cerevisiae.

Glucans are (1-->3)-beta-linked glucose polymers which have immune-stimulating capability. The extraction of water-insoluble (1-->3)-beta-D-glucan form Saccharomyces cerevisiae employs hydrochloric acid. Hydrochloric acid is difficult to employ in the large-scale pharmaceutical extraction of glucans due to its corrosive nature and toxicity. To address these concerns, we determined whether acetic, formic or phosphoric acid can be substituted for hydrochloric acid in the process for the isolation of (1-->3)-beta-D-glucan. The resulting microparticulate glucans were employed as the starting material for the production of (1-->3)-beta-D-glucan phosphate. 13C NMR analysis of the glucan phosphates derived from the acetic, formic or phosphoric acid-extracted microparticulate glucan show excellent correspondence to hydrochloric acid extracted glucan and laminarin, a (1-->3)-beta-D-glucan standard, indicating that the primary structure is not altered by the acid used for extraction. Glucan phosphate prepared from hydrochloric acid had a Mw of 7.2 x 10(4) g/mol, rmsz of 17.7 nm, of 1.50 and (eta) of 49.0 mL/g. Glucan phosphate prepared from acetic acid had a primary polymer peak with a Mw of 1.4 x 10(6) g/mol, rmsz of 23.6 nm, I of 1.93 and (eta) of 62.4 mL/g. Glucan phosphate prepared from formic acid had a main polymer peak with a Mw of 1.2 x 10(6) g/mol, rmsz 27.1 nm, I of 1.56 and (eta) of 89.0 mL/g. Glucan phosphate prepared from phosphoric acid had a primary polymer peak with a Mw of 6.6 x 10(5) g/mol, rmsz of 32.3 nm, I of 2.70 and (eta) of 91.3 mL/g. These data indicate that the molecular mass, size, polydispersity and intrinsic viscosity of the glucan phosphate obtained is influenced by the pKa of protic acid employed to extract the microparticulate glucan. However, the primary structure and side-chain branching are not substantially altered regardless of the acid employed.

Acetic Acid↗
PubMed1997

Analysis of 12-oxo-phytodienoic acid enantiomers in biological samples by capillary gas chromatography-mass spectrometry using cyclodextrin stationary phases.

The octadecanoid plant growth regulator 12-oxo-phytodienoic acid (12-oxo-PDA), which is also an intermediate in the biosynthesis of jasmonic acid, is obtained from 13-hydroperoxylinolenic acid via an unstable allene oxide generated by the enzyme allene oxide synthase. Recombinant, bacterially expressed and purified allene oxide synthase from Arabidopsis thaliana yields racemic 12-oxo-PDA as a mixture of 94:6 cis:trans diastereomers. In the presence of allene oxide cyclase from Solanum tuberosum, a product of high enantiomeric purity was obtained, which was shown to be (+)-cis-12-oxo-PDA (98:2 cis:trans diastereomers). Based on this coupled reaction, a preparative procedure was developed that yields pure (+)-cis-12-oxo-PDA in milligram quantities. Furthermore, an analytical technique employing capillary gas chromatography-mass spectrometry and beta- or gamma-cyclodextrin stationary phases was developed that enables the direct analysis of nanogram amounts of enantiomers of 12-oxo-PDA, as their methyl esters, in plant tissues. In the species analyzed, endogenous cis-12-oxo-PDA is the (+)-enantiomer.

Cyclodextrins↗
PubMed1997

Comparative biochemical characterization of the iron-only nitrogenase and the molybdenum nitrogenase from Rhodobacter capsulatus.

The component proteins of the iron-only nitrogenase were isolated from Rhodobacter capsulatus (delta nifHDK, delta modABCD strain) and purified in a one-day procedure that included only one column-chromatography step (DEAE-Sephacel). This procedure yielded component 1 (FeFe protein, Rc1Fe), which was more than 95% pure, and an approximately 80% pure component 2 (Fe protein, Rc2Fe). The highest specific activities, which were achieved at an Rc2Fe/Rc1Fe molar ratio of 40:1, were 260 (C2H4 from C2H2), 350 (NH3 formation), and 2400 (H2 evolution) nmol product formed x min(-1) x mg protein(-1). The purified FeFe protein contained 26 +/- 4 Fe atoms; it did not contain Mo, V, or any other heterometal atom. The most significant catalytic property of the iron-only nitrogenase is its high H2-producing activity, which is much less inhibited by competitive substrates than the activity of the conventional molybdenum nitrogenase. Under optimal conditions for N2 reduction, the activity ratios (mol N2 reduced/mol H2 produced) obtained were 1:1 (molybdenum nitrogenase) and 1:7.5 (iron nitrogenase). The Rc1Fe protein has only a very low affinity for C2H2. The Km value determined (12.5 kPa), was about ninefold higher than the Km for Rc1Mo (1.4 kPa). The proportion of ethane produced from acetylene (catalyzed by the iron nitrogenase), was strictly pH dependent. It corresponded to 5.5% of the amount of ethylene at pH 6.5 and was almost zero at pH values greater than 8.5. In complementation experiments, component 1 proteins coupled very poorly with the 'wrong' component 2. Rc1Fe, if complemented with Rc2Mo, showed only 10-15% of the maximally possible activity. Cross-reaction experiments with isolated polyclonal antibodies revealed that Rc1Fe and Rc1Mo are immunologically not related. The most active Rc1Fe samples appeared to be EPR-silent in the Na2S2O4-reduced state. However, on partial oxidation with K3[Fe(CN)6] or thionine several signals occurred. The most significant signal appears to be the one at g = 2.27 and 2.06 which deviates from all signals so far described for P clusters. It is a transient signal that appears and disappears reversibly in a redox potential region between -100 mV and +150 mV. Another novel EPR signal (g = 1.96, 1.92, 1.77) occurred on further reduction of Rc1Fe by using turnover conditions in the presence of a substrate (N2, C2H2, H+).

Bacterial Proteins↗
PubMed1997

Influence of heavy metal ions on antibodies and immune complexes investigated by dynamic light scattering and enzyme-linked immunosorbent assay.

The effect of Cd2+, Pb2+, Hg2+ and Cu2+ on the aggregation behaviour of monoclonal rat-IgG1-anti-mouse antibodies (kappa-light chain specific) and their antibody-antigen complexes with monoclonal mouse-IgG1 is reported. Investigations were done using the dynamic light scattering method. Cd2+ ions affected the hydrodynamic properties of the antibodies and the immune complex formation very little. More than 4 Cu2+ ions per antibody molecule led to large insoluble aggregates. Pb2+ ions also interacted with antibodies and immune complexes. Instead of "monomeric' antibodies (Ab) or immune complexes (Ab1Ag1), large soluble aggregates were detectable in the solution. Hg2+ ions induced complex formation with 3-4 antibodies per aggregate. Possible kinds of interaction are discussed. Additionally, we tested the antigen binding activity of metal-treated antibodies in ELISA-tests. The Sandwich ELISA technique was used to investigate the serological activity of the metal-treated antibodies, i.e., the reaction with the specific antigen. For these experiments we used the same monoclonal antibodies, mouse-IgG1 and rat-IgG1-anti-mouse. The influence of the above mentioned heavy metal ions was investigated up to a 10-fold molar excess over the antibody concentration. Even at these "unphysiological' high metal ion concentrations an inhibition of the antibody-antigen binding activity was not detectable.

Antibodies, Monoclonal↗
PubMed1997

Hydrodynamic properties of nitrogenase--the MoFe protein from Azotobacter vinelandii studied by dynamic light scattering and hydrodynamic modelling.

Experimental results for the nitrogenase MoFe protein from Azotobacter vinelandii obtained by dynamic light scattering (DLS) are presented. The translational diffusion coefficient was determined to D = (4.0 +/- 0.2) x 10(-7) cm2/s. Complementary, we have performed hydrodynamic model calculations based on the X-ray crystallographic data of the MoFe protein. The calculated transport coefficient suggests that the size and shape of the protein in solution is consistent with that in the crystal structure.

Azotobacter vinelandii↗
PubMed1997

Molecular genetic analysis of a patient with hereditary nonpolyposis colorectal cancer syndrome.

Hereditary nonpolyposis colorectal cancer types I and II constitute approximately 5% to 10% of the cases of colorectal cancer annually. Recognition of its clinical features and identification of affected families are imperative for appropriate medical and surgical management. Furthermore, molecular analysis can be performed in such families because the DNA mismatch repair genes have been identified as being mutated, thereby leading to microsatellite instability. We describe a 33-year-old woman with ovarian, uterine, and colorectal cancer, whose family, on close examination, had features consistent with hereditary nonpolyposis colorectal cancer. The patient had evidence of microsatellite instability in her colon cancer.

Adult↗