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Biomedical subjects

R Schuster

Publications and source records attributed to R Schuster.

At least 19 recordsLinked to original sources
PubMed1992

A new simulation approach for the determination of the error of parameters of biological importance describing the growth of the Ehrlich ascites tumor of the mouse.

Some aspects of the growth of the Ehrlich ascites tumor of the mouse can be described by the logistic function. The parameters used are fitted to the experimental data in a nonlinear way. It is important to determine the error of these parameters of biological importance in order to discriminate between different consequences induced by various experimental situations by means of statistics. But often there is a gap between the data that are available and the stronger assumptions necessary for statistics. We propose a simulation approach which also works in a much larger range of similar situations to close this gap.

Animals↗
PubMed1992

Budd-Chiari syndrome as the primary manifestation of a fibrolamellar hepatocellular carcinoma.

An 18-year-old female patient was admitted with ascites, right upper abdominal tenderness and peripheral edema. Angiography showed complete occlusion of the vena cava inferior up to the level of the right atrium. By open heart surgery, masses of thrombotic material were pulled out of the v. cava inferior/vv. iliacae which histologically contained tumor cell populations consistent with a hepatocellular carcinoma. Celiacography showed a highly vascularized tumor in the right hepatic lobe. Histologically, it proved to be fibrolamellar subtype hepatocellular carcinoma.

Adolescent↗
PubMed1992

[The modification of Helicella obvia by Dicrocoelium parthenitae].

During the pasture period in 1990 the snail species Helicella obvia, collected in a dicrocoeliosis area in the east of Brandenburg, was investigated for Dicrocoelium sporocysts. Simultaneously in adult snails the condition of albumen gland was examined. Investigations showed that Dicrocoelium infection in the snail host impairs their reproduction ability and life expectancy. The term "parasite caused sterilisation" is suggested for changes which lead to infertility in the case of parasite infection.

Animals↗
PubMed1991

Minimization of intermediate concentrations as a suggested optimality principle for biochemical networks. II. Time hierarchy, enzymatic rate laws, and erythrocyte metabolism.

The multiobjective problem of minimizing all intermediate concentrations is solved for a model of glycolysis, the pentose monophosphate shunt and the glutathione system in human erythrocytes. It turns out that one solution out of four obtained corresponds qualitatively to the real system. Furthermore, it is shown that for any reaction system, the mentioned optimality principle implies distinct time hierarchy in that some reactions are infinitely fast and subsist in quasi-equilibrium. Finally, the relationships to the standard method of deriving enzymatic rate laws are discussed.

Energy Metabolism↗
PubMed1991

Factors influencing the metacercarial intensity in ants and the size of Dicrocoelium dendriticum metacercarial cysts.

During the 1990 grazing season, ants found attached to plants were collected from sheep pastures at monthly intervals and examined for Dicrocoelium metacercariae. The species Formica pratensis and F. rufibarbis showed average metacercarial intensities of 76 and 38 respectively. In addition to the ant species, the intensity of infection was found to be dependent on the length of the ant. The volume of metacercarial cysts was influenced by the intensity per ant relative to ant length but not by the ant species or the time of ant collection.

Animals↗
PubMed1979

[Phlebography (author's transl)].

The article discusses the limitations of conclusive information supplied by different phlebographic methods. Particular attention is drawn to the insufficient staining properties, partly of the deep veins of the lower leg, the vena femoralis profunda and gastrocnemius veins. When assessing the course of acute phlebothromboses, conclusive information on the extent of thrombus formation is limited in complete obstruction of deep veins as well as in the reformation of thrombi in vessels which have already undergone post-thrombotic changes. Observation of the valvular function can supply essential information on the extent of fibrinolytic effects. Besides the conventional phlebographic techniques, the article also explains methods for the visualisation of rare angiomatoses with osseous involvement, using transosseous pelvic phlebography.

Angiomatosis↗
PubMed1978

The effect of blood infusion upon endurance capacity and ratings of perceived exertion.

The purpose of this investigation was to study the effect of blood infusion upon maximal endurance capacity and ratings of perceived exertaion (RPE). Sixteen long-distance runners, 13 of whom were marathoners, undertook four trials (T1-T4) of a treadmill run to exhaustion over a five week period. Criterion measures were time to exhaustion (TE) and RPE during each T. Data on Hb, Hct and RBCs were collected prior to each trial. Based on TE at T1, Ss were matched and assigned to either the experimental (E) or control (C) group. One week after T1, all Ss had 460 ml blood withdrawn. T2 was undertaken 2 weeks postwithdrawal. One week after T2, or 21 days postwithdrawal, the E group was infused with their own RBCs while the C group received 460 ml normal saline. T3 was taken 2 hours postinfusion and T4 one week later. The results of the factorial repeated measures ANOVA revealed no significant differences (p less than .05) between groups for either TE or RPE, even though the Hb level for the E group was significantly higher (P less than .01) than the C group at T3 and T4.

Analysis of Variance↗
PubMed1978

[Technique and use of percutaneous transhepatic cholangiography (PTC) with the CHIBA needle (author's transl)].

Experiences with the modified percutaneous transhepatic Cholangiography (PTC) with the CHIBA-needle ("skinny-needle") are evaluated and reported. The procedure is successul in almost all cases with dilated bile ducts. Therefore a failure to opacify the bile ducts with this method suggests an intrahepatic cause of cholestasis. No serious side effects have been observed in 45 cases.

Cholangiography↗