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Biomedical subjects

F Trendelenburg

Publications and source records attributed to F Trendelenburg.

At least 37 records · Page 2Linked to original sources
PubMed1979

[New aspects in the treatment of allergic asthma (author's transl)].

Preventive measures in atopic persons comprise genetic advice, identification of, and prevention of contact with, the more common antigens in infancy and, later on, avoidance of exposure to antigens during the flowering season. In view of the complexity of the asthmatic attack the diagnosis must include all relevant parameters as otherwise consistent treatment is impossible. The only causal therapy is avoidance of exposure to antigens and also to unspecific (physicochemical) noxae which are nearly always superimposed. The value of specific immunotherapy varies according to the antigen or combination of antigens. The final verdict has to await the results of controlled studies in carefully classified and analysed groups, including investigations of immune parameters and uninterrupted registration of exposure to antigens. Until the efficiency, indications and mode of application of immunotherapy have been clearly established desensitization is preferable, provided the allergen has been identified and proved to be active, and exposure to the antigen cannot be avoided. The relatively high success rate obtained with placebos is presumably attributable to concurrent symptomatic treatment and avoidance of contact with the antigen. The already broad spectrum of adjuvent therapy is being constantly and successfully enlarged. Attempts to stimulate the production of antigen-specific suppressor T-cells by denatured antigens, and thereby prevent IgE production, are promising. Until a causal anti-allergy therapy has been developed a carefully and individually planned somatic and psychic polytherapy must remain the rule.

Adult↗
PubMed1975

Effects of actinomycin D on the association of newly formed ribonucleoproteins with the cistrons of ribosomal RNA in Triturus oocytes.

The effect of actinomycin D(AMD) on the association of the nascent ribonucleo-protein (RNP) fibrils containing the precursors of ribosomal RNA (pre-rRNA) with their template deoxyribonucleoprotein (rDNP) strands has been studied in lampbrush stage oocytes from Triturus alpestris. Ovary pieces were incubated in vitro either in media containing radioactive ribonucleosides and then, for various times, in solutions containing 25 mug/ml AMD, or were directly exposed to the drug. The ultrastructure of the nucleoli and the nuclear periphery was studied by electron microscopy of thin sections and positively stained spread preparations of isolated nuclear contents, and by light and electron microscope autoradiography. The fate of the labeled pre-rRNA was followed by gel electrophoresis of RNA extracted from manually isolated nuclei. Our results show that the growing fibrils which contain the nascent pre-rRNA progressively detach from the DNP strands, the majority being released between 45 and 180 min after application of the drug. The release pattern seems to be random and does not show preference for regions close to the initiator or terminator sites of the transcribed rDNP units. There is a pronounced tendency to removal of groups of adjacent mascent fibrils. The effect of the drug is very heterogeneous. Even after 3 h of treatment with AMD the nucleoli exhibit several individual transcriptional units which appear almost completely covered with lateral fibrils. Autoradiography revealed that most of this released RNP remains within the confinements of the nucleoli which show some foci of aggregation and condensation of fibrillar components but no clear "segregation" phenomenon. In the gel-electrophoretic analysis, a significant but moderate decrease of labeled pre-rRNA was noted only in the first stable pre-rRNA component, whereas pre-rRNA classes of lower molecular weight are very stable under these conditions. The results are discussed in relation to the stability of rDNA transcription complexes and as a basis for an explanation of the ultrastructural changes which are generally observed in nucleoli of AMD-treated cells. It is postulated that inhibition of transcription results in a slow but progressive release of the arrested incomplete RNP fibrils from the template.

Animals↗