Biomedical subjects
Publications and source records attributed to A Steiner.
Volterra's (1926) equations for competition and predator-prey interactions are modified by introduction of root terms. A critical comparison with the original equations shows that the dynamic properties of the systems remain essentially alike, while the modification allows for explicit solution of the differential equations. Detailed solutions and numerical examples are given.
By immunocytochemical methods, the protein effectors of known intracellular signal molecules were demonstrated in the thyroid follicular cell and their localization investigated. Cyclic AMP protein kinase subunit RII was clearly located in the nucleus. Protein kinase subunits RI and C were in the cytosol and on the apical membrane. Cyclic GMP kinase and calmodulin were mostly found in the cytoplasm and at the apical membrane; they were poorly represented in the nucleus. The only membrane underlined by several markers was the apical membrane, i.e. the site of iodination, oxido reduction and H2O2 generation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
In order to compare the external fixator of the Arbeitsgemeinschaft für Osteosynthesefragen (AO) to different types of assembly of the Stuhler-Heise fixator (frame fixator, three-dimensional fixator, three-dimensional fixator with two screws of Schanz) with different spans (110, 140 and 190 mm), a vertical and excentric stress was exerted on a defect on the fracture gap. The comparable types of assembly of the AO fixator were lighter by 20% on an average. In two thirds of all assemblies, i.e. in 12 among 18 assemblies, the Stuhler-Heise device showed markedly better results of stability at the simulated fracture gap with respect to a vertical downward movement. In three assembly series there were identical results, in the other three series the AO device brought about better results. Under excentric stress, both fixator types showed considerable torsion movements from the horizontal line within the fracture gap. The differences between the two fixator systems found out for defects on the fracture gap will probably be significantly less important in case of compression osteosynthesis. This assumption will be verified by further examinations.
Explore the source record for details and available documents.
Praziquantel was compared to niridazole in schistosomiasis intercalatum in the Gabon. In a pilot study, 45 patients were randomly allocated to the two treatment groups. After treatment, 36 of these patients could be evaluated. Though the seven-day niridazole treatment showed significant reduction of egg excretion in all patients, cure rate was rather low. 9 out of 17 patients (53%) still excreted viable eggs of Schistosoma intercalatum. In contrast, patients treated with praziquantel in a one-day treatment (2 x 30 mg per kg) showed a persistent excretion of viable eggs in 3 out of 19 cases (16%). This difference was significant (p less than 0.025). Although the number of patients observed is rather small, results indicate that praziquantel is superior to niridazole in the treatment of schistosomiasis intercalatum both in view of application and side effects as well as curative potential.
The diagnostic value of the rectal biopsy was compared to a quantitative stool filtration and the MIF concentration technique in schistosomiasis intercalatum in the Gabon. The rectal biopsy was significantly more sensitive in proving the presence of ova of Schistosoma intercalatum than the stool filtration (p less than 0.001). However, if the two techniques were compared on the basis of the capability to detect viable eggs in rectal mucosa or stool, no difference in sensitivity could be found. The MIF concentration technique was significantly less sensitive than the stool filtration (p less than 0.01) and seems only of minor diagnostic value in schistosomiasis intercalatum. It could be shown that the relative sensitivities of the three techniques in detecting S. intercalatum eggs depended on the age of the examined population, as presence of viable eggs in rectal mucosa and excretion of eggs in stool was inversely correlated to the age of the patients.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Antihistaminic drugs may interfere with ion and water transport across bronchial epithelium, decreasing the water content of the bronchial mucus and thus adversely affecting mucociliary clearance. A double-blind trial was therefore undertaken to study the short-term effects of ketotifen, a new antiasthmatic drug with antianaphylactic and antihistaminic properties, on the physicochemical properties of sputum in 16 patients with clinically stable chronic reversible airway diseases. The study lasted 5 weeks, during which the patients received 2 mg ketotifen daily for two or three weeks and placebo for the remaining weeks; thus, all patients received both the active drug and a placebo. The patients were evaluated weekly and different measurements, including graded clinical observations, ventilatory tests and blood studies were carried out. Objective sputum measurements included 24-hour volume, dry weight, "apparent" viscosity (at a shear rate of 900 s-1), content of fucose, neuraminic acid, immunoglobulin A and acid mucus glycoprotein fibers. Of the sputum characteristics the daily volume decreased slightly after ketotifen. In contrast, sputum dry weight appeared to increase. The "apparent" viscosity showed a tendency to decrease. Fucose, neuraminic acid and immunoglobulin A content varied slightly, as did the percentage of acid mucus glycoprotein fibers. Since none of the sputum characteristics changed significantly during short-term therapy with ketotifen, this drug probably does not alter either the water content or the mucus biopolymers--both of which are responsible for the flow properties of bronchial mucus--thus presumably leaving mucociliary transport unchanged in patients with chronic reversible airway diseases.
Antigen stimulated changes in cyclic AMP levels which are the result of increases in prostaglandin levels, were measured by immunofluorescence in frozen spleen sections. The results provide direct visual confirmation of previous reports in that an increase in the number of cells staining positively for cyclic AMP were detected. The increase in cyclic AMP levels occurs in approximately 40% of the cells in the cortical region of the spleen. No staining was observed in deeper regions. Using sRBC as a particulate antigen and DNP-BGG as a soluble antigen, it was possible to show that a slightly smaller increase in the number of cyclic AMP positive cells occurs using DNP-BGG compared to sRBC. These data mean that antigen stimulated changes in splenic AMP levels occurs in a much larger population than could be accounted for on the basis of antigenic specificity. Such a result is consistent with previous data showing the increase in cAMP is a result of a prior increase in prostaglandin. Thus, any cell bearing a prostaglandin receptor could respond by showing an elevated cAMP level.
Explore the source record for details and available documents.
Explore the source record for details and available documents.