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Biomedical subjects

T Wüst

Publications and source records attributed to T Wüst.

13 recordsLinked to original sources
PubMed2005

Influence of solid solution formation on polarity: molecular modeling investigation of the system 4-chloro-4'-nitrostilbene/4,4'-dinitrostilbene.

Growth-induced polarity formation in solid solutions composed of dipolar 4-chloro-4'-nitrostilbene molecules and nonpolar 4,4'-dinitrostilbene molecules was investigated by means of two molecular modeling procedures. Calculation of the mixing energy in the bulk structures predicted solid solution formation within the whole composition range. Computation of the interaction energies present at growing surfaces allowed the distribution coefficient as well as the fraction of dipoles in either the up or down orientation to be calculated by a mean-field model. Miscibility and polarity were found to vary for the faces (hkl) investigated, leading to crystals composed of sectors with different compositions and polarities. The present study highlights the fact that a solid solution crystal may not be a homogeneous entity and that surface effects arising during slow growth can have an impact on solid state properties.

Journal Article↗
PubMed2000

Biomarkers of genetic damage and inflammation in blood and bronchoalveolar lavage fluid among former German uranium miners: a pilot study.

Former East German uranium miners who are known to have been exposed to radon are estimated to be at high risk for lung carcinogenesis. Among these miners over 200 occupationally caused lung cancer cases are expected to occur each year, resulting in a total of 7,000-24,000 excess lung cancer cases in the coming years. It is still unknown whether there is a correlation between biomarkers and the exposure of the uranium miners to ionizing radiation that might enable us to trace those miners with high lung cancer risk. The primary aim of this pilot study was to test the possibility of performing a biomarker study in this unique cohort of former uranium miners in spite of several limitations that had to be taken into consideration when comparing them with healthy controls, such as old age, age-dependent diseases and potential confounding artefacts from dissimilar smoking patterns. The second aim was to test a range of biomarkers for DNA damage and inflammation in leukocytes and bronchoalveolar fluid for their ability to detect biological effects. In this cohort of miners we found an increased frequency of chromosomal aberrations in blood lymphocytes and an increased prevalence of both fibronectin and tumour necrosis factor alpha in the bronchoalveolar fluid.

Aged↗
PubMed1996

[Specificity of a new test for detection of antibodies to HIV-1/-2 in blood donors].

BACKGROUND: The aim of the continuous development of anti-HIV-ELISA tests is the improvement of their specificity and sensitivity. With this study the precision and the specificity of the Cobas Core Anti-HIV-1/HIV-2 DAGS, a 3rd-generation anti-HIV assay, were evaluated. MATERIALS AND METHODS: 1,557 frozen and 1,654 fresh sera from blood donors were tested with the Cobas Core Anti-HIV-1/HIV-2 DAGS (Roche Diagnostic Systems, Basel, Switzerland) and the Abbott Recombinant HIV-1/HIV-2 3rd Generation EIA (Abbott GmbH Diagnostika, Wiesbaden, Germany), which was used as a reference assay. Positive sera were tested with a Westernblot. 34 sera, previously not negative in the Abbott test, were retested with the two anti-HIV assays and with a Westernblot. The intra- and inter-assay precision was evaluated with the positive and negative controls of the test kits and with control sera. RESULTS: The intra- and inter-assay precision of the Roche test was very good. The specificity of the Roche test is 99.91%. Out of 3,211 tested sera those of three blood donors were false positive in the Roche test and one sample false positive in the Abbott test. CONCLUSIONS: The precision and specificity of the new anti-HIV test fulfil the demands of transfusion medicine.

AIDS Serodiagnosis↗
PubMed1995

Short-time rabbit model of endotoxin-induced hypercoagulability.

We describe a short-time endotoxin-induced rabbit model of hypercoagulability for the study of the coagulation cascade and the therapeutic effects of coagulation inhibitors. Cardiorespiratory function was maintained in rabbits under general anesthesia and standardized mechanical ventilation (tidal volume, 6 ml/kg; 60 breaths/min) via tracheostomy and low-dose inotropic support. Coagulation parameters such as prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, platelet count, fibrin monomers, D-dimers, antithrombin III and factor XIII activities, thrombelastography, and platelet aggregometry were measured during a 4-h period after sequential double endotoxin administration (80 and 40 micrograms/kg of body weight, intravenously). Mean arterial pressure and arterial and central venous blood gas tensions were monitored. Global clotting, activation parameters of coagulation, and leukocyte count deteriorated significantly in the endotoxin-treated animals but was mainly unaltered in controls (P < 0.05). Tissue specimens of the lungs, liver, brain, and kidneys were examined. Endotoxin-induced, disseminated fibrin deposition was found in the lungs and liver (P < 0.01). We conclude that this short-time model of hypercoagulability in rabbits reliably induced disseminated intravascular coagulation. Tracheostomy and mechanical ventilation provided a reproducible model in which the differences between the controls and the endotoxin-treated animals were exclusively due to administration of endotoxin and not to unforeseen complications of the respiratory system. This model allows the study of therapeutic effects of coagulation inhibitors on endotoxin-induced changes.

Animals↗
PubMed1992

Two years serial lymphocytapheresis of progressive hyperleukocytosis in a patient with a non-Hodgkin's lymphoma.

A patient with non-Hodgkin's lymphoma was treated by ambulant lymphocytapheresis once a month over a period of 2 years and 8 months. The cytoreductive effect resulted in a decrease of white blood cells from 410/nl to 130/nl. The patient tolerated the procedure, which lasted 3-4 h, without any side effects. He could be kept in good condition by monthly apheresis. So lymphocytapheresis is a means to reduce hyperleukocytosis in patients with non-Hodgkin's lymphoma.

Ambulatory Care↗
PubMed1992

Detection of antibodies to hepatitis C virus in blood donors and their relationship to surrogate markers.

Stored serum samples from 7,179 nonselected blood donors were tested for anti-HCV using Ortho EIA first generation. Results were compared to data acquired by anti-HBc testing and ALT levels found in routine testing. 24 donors (0.33%) were repeatedly reactive with Ortho HCV EIA, 230 (3.20%) were anti-HBc-positive and 138 (1.92%) had raised ALT levels > or = 36 IU/l. A low correlation was found between HCV antibody screening with EIA and surrogate testing. When tested in addition with the Abbott HCV EIA, 20 of the 24 Ortho EIA-positive subjects showed a positive reaction. In the Abbott neutralization test 13 of these 20 (65%) were reactive. 8 (33.33%) of the 24 Ortho-EIA-positive donors were positive in the two-antigen-RIBA (first generation), 8 were indeterminate and 8 were nonreactive. The neutralization test and the RIBA can be used as supplementary tests fo further analyze HCV-EIA-positive specimens.

Blood Banks↗
PubMed1991

Influence of different surfactants on the separation of von Willebrand factor multimers by use of agarose gel electrophoresis and semi dry blotting technology.

The separation of vWF-multimers by use of sodium dodecyl sulfate (SDS) agarose gel electrophoresis and semi dry blotting instead of tank blotting procedure has been studied. We could demonstrate, that multimers in the range of highest molecular weights could not be visualized using this technique. Therefore we have investigated the influence of different types of anionic surfactants on the separation of vWF-multimers and could show that the hydrophilic/lipophilic balance (HLB) is an important value to characterize the capacity of a surfactant to separate vWF-multimers. The best separation quality was achieved with sodium dodecyl benzene sulfonate (SDBS). This surfactant is a superior alternative to SDS in separating vWF-multimers of the highest molecular weights.

Benzenesulfonates↗
PubMed1986

[Procedures for the isolation and characterization of human antithrombin III].

Antithrombin III, the most important inhibitor of activated coagulation factors (IIa, IXa, Xa, XIa, XIIa) was isolated from human plasma by affinity chromatography. The biochemical characterization of this highly purified inhibitor showed, that is was uniform by means of HPLC and PAA gradient gel electrophoresis. The molecular weight was determined to 70000 daltons and the isoelectric point was pH 4,5. The inhibition of factor Xa by AT III had been proofed as competitive by kinetic studies. AT III works as a "dead end inhibitor". Heparin seems to form a ternary complex with AT III and activated coagulation factors, so acting as a catalyst. The therapeutic value of AT III-concentrates will be discussed.

Antithrombin III↗