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Biomedical subjects

B Schumann

Publications and source records attributed to B Schumann.

27 records · Page 2Linked to original sources
PubMed1984

Influence of tryptophan and related compounds on ergot alkaloid formation in Claviceps purpurea (FR.) Tul.

L-Tryptophan did not exert any influence on peptide alkaloid formation in an ergotamine and in an ergosine-accumulating C. purpurea strain. A different picture was observed in a series of related C. purpurea strains. Tryptophan showed a slight stimulatory effect on the ergotoxine producer Pepty 695/S. A blocked mutant of it, designated as Pepty 695/ch which was able to accumulate secoclavines gave similar results. In a high-yielding elymoclavine strain Pepty 695/e, the progeny of the former one, tryptophan up to a concentration of 25 mM stimulated remarkably clavine biosynthesis. Furthermore, tryptophan could overcome the block of synthesis by inorganic phosphate. Increased specific activities of chanoclavine cyclase but not DMAT synthetase were observed in cultures of strain Pepty 695/e supplemented with tryptophan. 5-Methyltryptophan and bioisosteres of tryptophan were ineffective in alkaloid stimulation. These results are compared with those obtained with the grass ergot strain SD 58 and discussed with the relation to other induction phenomena.

Chemical Phenomena↗
PubMed1984

[Immunologic studies in patients with Crohn disease and ulcerative colitis].

To compare patients with Crohn's disease and patients with ulcerative colitis we have studied some immunological parameters (level of IgM, IgG and IgA in the serum, number of lymphocytes, E rosettes) and the immunological reactivity to antigens from colon carcinoma and to colon antigens prepared from healthy and from colon tissue altered by Crohn's disease (antigen specific rosette test, MEM-test, antibody titer). The results indicate a decreased proportion of T cells in both bowel diseases on the one hand, on the other hand a specific cell-meditated immune reaction to colon antigens could be observed in patients with Crohn's disease. In patients with ulcerative colitis such reactions are determined only in the acute phase of disease or in recidive. It remains to be elucidated whether these immunological reactions represent a basic pathogenetic factor in the onset of these diseases.

Antigens, Neoplasm↗
PubMed1983

Mutagenicity of cyanate, a decomposition product of MNU.

Knox reported that the short-term effects of the carcinogen methylnitrosourea (MNU) were due to the formation of its decomposition product, the cyanate ion. He showed that cell survival and DNA synthesis decreased as the concentration of MNU and the cyanate ion (NCO-) increased in the medium. Further, the product of MNU decomposition comigrated with NCO- when added to his chromatographic test system. However, Knox did not study the mutagenicity of MNU or its breakdown products. We compared the mutagenicity of MNU and potassium cyanate (KNCO) in mammalian cells. Our results demonstrate that, although it is toxic to cells, KNCO does not induce ouabain-resistant mutants in cultured Chinese hamster cells (V79).

Animals↗
PubMed1973

Antibody to HSV-2 induced tumor specific antigens in serums from patients with cervical carcinoma.

Antibody distinct from that involved in neutralization and directed to an antigen (AG-4) induced in HEp-2 cells by infection with herpesvirus type 2 was identified in serums from patients with cervical carcinoma by means of a quantitative micro complement fixation test. The presence of antibody to AG-4 correlates well with the extent of the tumor; antibody is virtually absent in matched control women and in women with therapy and without recurrent neoplasia. Reactivity is not observed with control antigen consisting of a cell extract prepared from uninfected HEp-2 cells. The possible prognostic significance of this antibody and its implications are discussed.

Adult↗
PubMedDate not supplied

Correlation of biochemical tumor markers with conventional pathological features in primary breast cancer.

In this prospective study the correlation of pathological with biological prognostic factors and serum tumor markers has been investigated in 574 patients with primary invasive breast cancer. The p53 protein and Bax level correlated positively with tumor size, lymph node status and histological grade. The serum levels of CEA, CA 15.3, TPA-M and TK correlated with tumor extent. There was a significant difference between pre- and postmenopausal breast cancer patients in serum levels of TPA-M and cytosol levels of Bax. Whether these correlations can help in predicting the prognosis of breast cancer by providing additional information with respect to the conventional factors, will have to be investigated by several years of careful clinical follow-up.

Biomarkers, Tumor↗