Biomedical subjects
Publications and source records attributed to G Schumann.
In a patient with upper abdominal pain real-time sonography produced the first relevant sign of a space-occupying gastric lesion. Final diagnosis was gastric hemangiopericytoma.
The comparative bioavailability of two commercial carbamazepine tablets (Finlepsin and Tegretol) was investigated. In a single-dose study in eight healthy volunteers and in a multiple-dose study in five epileptic patients carbamazepine absorption from both drug products was shown to have the same extent and reliability. Despite a somewhat increased rate of absorption in Finlepsin, as regards the fit of the drug level in the therapeutic range under chronic treatment conditions, there was no difference between the two preparations. On the basis of these results we conclude that Finlepsin and Tegretol are bioequivalent drug products.
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It was found that genetic recombination occurs if two marked strains of Streptomyces griseus (leukaemomycin-producing strains IMET JA 3933 and IMET JA 5142) are grown together in mixed cultures on semisolid media. The crossing techniques used and the method for carrying out selective analysis were essentially the same as those described by HOPWOOD (1967, 1972). The parent strains used for crosses were marked with single or double nutritional requirements and with mutations for drug resistance. The crosses are quite self-sterile, yielding only in one combination stable prototrophic recombinants at a low frequency (10(-5) to 10(-6)). The majority of recombinants behaved as stable haploid genotypes. A series of four-point crosses of different types of auxotrophs was carried out. The results of these experiments do not provide sufficient data for constructing a chromosome map, but provide basic information on the possibilities of genetic analysis of the production of anthracycline antibiotics. The majority of crosses performed were not fertile at 28 degrees C but, surprisingly, in some crosses carried out at 34 degrees C viable colonies were detected on minimal media at frequencies from 10(-3) to 10(-2).
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In a continuing search for fertility mutants of the turimycin-producer, Streptomyces hygroscopicus, strain IMET JA 6599, from more than 683 pairs of auxotrophic mutants 19 pairs were found to develop colonies after replica plating on selective media. The frequency of recombinant production in mixed cultures on complex medium varies from 10(-6) to 10(-2) in different combinations of S. hygroscopicus mutants. Typical frequencies representing the proportion of recombinant colonies (from spores and/or fragments of substrate mycelium) and a visual indication of the different fertility levels using the familial fertility test method are given in Tables and Figures. Additionally, reversion rates of markers and different types of colonies of fertility mutants used in some S. hygroscopicus crosses will be shown.
In a continued search for leukaemomycin-blocked mutants of three leukaemomycin-producing strains IMET JA 3933, IMET JA 5142 and IMET JA 5570 of Streptomyces griseus, 32 mutants producing aerial mycelium and spores were detected. Furthermore, in all mutants cosynthetic capability has been observed. This report describes characterization of leukaemomycin-blocked mutants obtained by mutagenic treatment experiments using NTG and combined UV-/X-rays. According to the biosynthetic capability for anthracyclinones or other pigments the mutants could be divided into six classes. The first class contains 14 leukaemomycin-blocked mutants unable to synthesize anthracyclinones. Besides two classes of mutants (12)synthesizing well-known anthracyclinones as epsilon-rhodomycinone, 7-deoxy-epsilon-rhodomycinone, 11-deoxy-derivatives of daunomycinone, three new classes of mutants (6) synthesizing reddish-brown, brown and blue-violet pigments on solid media with structures not elucidated as yet, will be described.
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Goat and rat antisera directed against Friend leukemia virus (anti-FLV) were found to be B-lymphocyte mitogens stimulating DNA synthesis in these cells but not in T lymphocytes. Membrane fluorescence microscopy showed that anti-FLV reacts with a subset of B lymphocytes of which the majority express immunoglobulin mu chains. The mitogenic effect was found with all mouse strains tested including 129 and AKR. Absorption experiments with purified viruses indicated that the mitogenic effect is specific for an antigen present in murine leukemia viruses of the FMR subgroup. In absorption experiments with viable cells, the antigen involved in mitogenicity was found to be expressed on Friend erythroleukemia cell lines (4/4) and on myelomas (2/2) but not on normal thymus T lymphomas (0/2) or on rabbit or mink cells infected with BALB/c xenotropic virus. Preincubation of spleen cells with anti-gp70 antiserum inhibited the mitogenic effect of anti-FLV but not of lipopolysaccharide.
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It is reported on complications of urological diseases in diabetes mellitus. Above all the diabetic late syndrome and its multiform and uncharacteristic symptomatology in the urogenital system are discussed in detail. The present form of diabetes control can not yet be regarded as optimum form. It should be striven for changes, since it is to be reckoned with an increase of diabetes mellitus all over the world.
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Lipoprotein E. coli, a B-cell mitogen, is identified as a new agent inducing the release of endogenous C-type virus from mouse spleen cells. Like lipopolysaccharide, a previously identified inducer, this compound has a synergistic effect with 5-bromo-2'-deoxyuridine. Induced virus has the characteristic density as well as morphology of C-type viruses. Budding viruses are detected on cultured BALB/c cells by electron microscopy 2 to 4 days following culturing in the presence of lipoprotein. Pokeweed mitogen, a compound mitogenic for T- and B-cells was negative when tested for virus induction, both alone and in combination with 5-bromo-2'-deoxyuridine. Dextran sulphate, another B-cell mitogen, was negative for induction as well. However, when, combined with lipopolysaccharide, it enhanced the virus release induced by this mitogen. In contrast, no additive effects were observed either by combining dextran sulphate with other virus amplifying mitogens or by combinations of mitogens which both have virus-inducing ability. This finding is discussed with respect to B-cell differentiation.