Zur Sauerstoffabhängigkeit der Rate strahleninduzierter Chromosomenaberrationen in Oozyten vonDrosophila melanogaster
SummaryAbrahamson's (1959) results concerning the influence of oxygen on the frequency of X-ray induced structural changes (half-translocations) inDrosophila oocytes were generally reproduced, especially the demonstration of a “reverse” oxygen effect (under special experimental conditions protecting action of oxygen, sensitization by nitrogen). In the course of our investigations the following new findings were obtained: 1. The added aberration frequencies of the 3rd and 4th day after the various treatments generally tend to decrease as compared with those of the first two days (dependence on state of maturity of the treated oocytes). 2.Preirradiation treatment by nitrogen increases the aberration frequency significantly. Possible explanations of this effect are discussed.
INDEPENDENT X-RAY EFFECTS ON CHROMOSOME BREAKAGE AND REUNION.
of micro-organisms for purposes of investigations of
Modulating dopamine receptors subtype selectivity by thiophene and benzothiophene based derivatives
In this work we tried to develop new dopaminergic ligands with novel affinity and selectivity profile towards the five different dopamine receptor subtypes; namely D1, D2, D3, D4, and D5 receptors to come up with new medical agents but with fewer side effects relative to those present in the medicinal market such as Haloperidol that is considered to be among the very famous typical antipsychotic agents characterized with Extrapyramidal symptoms adverse effects and Clozapine that represents the atypical antipsychotic agents that suffers agranulocytosis adverse effects. Among the fifty five synthesized ligands, compounds 3, 44a, and 45a were shown to have unique subtype receptor selectivity, thus could be promising atypical antipsychotic agents. Compound 3 was the first azecine derivative to show antagonistic action on both D2 and D5 receptor subtypes, (Ki (D2): 1.5 nM; Ki (D5): 1.9 nM). Compound 44a showed to be more than 200 times more selective to D2 receptors rather than D4 (Ki (D2): 138 nM; Ki (D4):0.62 nM). Compound 45a has shown to be more than 100 times more selective to D3 rather than D2 receptor subtypes and more than 900 times more selective to D4 rather than D2 receptor subtypes (Ki (D2): 28.5 nM; Ki (D3): 0.26 nM; Ki (D4): 0.03 nM).