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Biomedical subjects

W Scheid

Publications and source records attributed to W Scheid.

At least 55 records · Page 3Linked to original sources

Enhancement of bleomycin-induced DNA damage by exposing isolated DNA to high concentrations of the calcium antagonist verapamil.

The calcium antagonist verapamil was found to enhance synergistically the DNA (desoxyribonucleic acid) strand breakage activity of the radiomimetic antitumor agent bleomycin in vitro. The induction of single and double strand breaks in isolated DNA was investigated by agarose gel electrophoresis. Three types of DNA (two plasmids and one native eukaryotic DNA) were used as target molecules. The effect of verapamil was concentration dependent (concentration range tested: 0.75-3.0 mmol/l). However, at those low concentrations, as they were used in cytotoxicity assays and cytogenetic experiments, no potentiating effect of verapamil on bleomycin action could be observed. The significance of these findings is discussed with respect to various hypothesis concerning the potentiation of tumor drug efficiency by verapamil and other calcium antagonists.

Animals↗

Chromosome aberrations induced in human lymphocytes by an X-radiation accident: results of a 4-year postirradiation analysis.

After occupational and medical radiation exposures structural chromosome aberrations may be induced in the lymphocytes of the irradiated persons. Many authors have estimated the radiation dose from the yields of dicentric aberrations. We analysed the influence on the dicentric yield of increasing time intervals between irradiation and blood sampling from a person involved in an X-radiation accident (radiography). During a 4-year follow-up we observed an approximately 7-fold decline of the dicentric yield up to the 25th month and thereafter an almost constant value. Since the decline did not commence until around the 10th month after the exposure, an exponential decrease of dicentric yield with time should be considered with reservation in this study, although it cannot be entirely ruled out. We conclude that in 'biological dosimetry' blood should be sampled as early as possible after the exposure. Furthermore, computation of 'half-times' of lymphocytes to allow for a delay in blood sampling seems uncertain after partial body exposures to high doses. Therefore in such cases dose estimates obtained 1 or more years after irradiation should be considered as minimum values.

Accidents↗

[Neuropsychiatry today (author's transl)].

Neurology and psychiatry are combined in the easily misunderstandable term "Neuropsychiatry" as equal ranking sister disciplines. Neurology with its rectilinear development and the gain in important auxiliary methods enjoys general high respect. It is quite different with psychiatry. It is tainted with the events of the National Socialist domination. Its logical therapeutic methods are associated with inhumanity. Etiology and pathogenesis of the "endogenous" psychoses are still veiled in darkness. This gap in knowledge, detrimental to the prestige of psychiatry, is filled with theories, hypotheses and speculations. An extensively popularized psychology questions some concepts of a classical psychiatry wrongly described as conservative. Such uncertainty is alive even in the ranks of psychiatrists, to the detriment of their responsibility. Psychiatry must serve the care of the individual patient, renouncing all possible temptations. Some success can be expected from the "out-patient services" but this demands professional knowledge and critical ability besides activity.

Electroconvulsive Therapy↗