Microbial transformation of azacarbazoles X: Regioselective hydroxylation of 5,11-dimethyl-5H-indolo [2,3-b]quinoline, a novel DNA topoisomerase II inhibitor, by Rhizopus arrhizus

Summary Microbial transformation of cytotoxic 5,11-dimethyl-5H-indolo[2,3-b]quinoline (a compound displaying antitumor activity and affecting the activity of calf thymus DNA topoisomerase II) was performed by the Rhizopus arrhizus strain and yielded a 9-hydroxy derivative. The metabolite obtained displayed a stronger cytotoxity against KB cells than the parent compound (ID₅₀=0.001 mol/mL), and stimulated also the formation of calf thymus topoisomerase II mediated pSP65 DNA cleavage in vitro at the concentration of 3 M. Being analogous to 9-hydroxyellipticine (which is an antitumor alkaloid), this novel indolo[2,3-b] quinoline derivative can be regarded as a novel potential antitumor agent.     

A new species of Polystoma (Monogenea: Polystomatidae) parasitic in Hyperolius marmoratus (Anura: Hyperoliidae) in South Africa

Polystoma marmorati n. sp. is described as a new polystomatid species parasitic in the urinary bladder of the painted reed frog Hyperolius marmoratus marmoratus collected in southern Natal, South Africa. Parasite prevalence varied from 14.5 to 47.4% and the mean intensity from 1.0 to 1.1. The hamuli of the new species have a characteristic, partly fragmented appearance, a feature also seen in Polystoma batchvarivi, the only other polystome described from a species of the genus Hyperolius. The similarity between the two species, in spite of their geographical separation, is commented upon.     

Fructosamine in human and bovine semen.

We detected the presence of fructosamine in human and bovine semen. In seminal plasma of healthy normozoospermic men (N = 17) fructosamine was found in 53% of the cases (fru+). In fru+ semen samples the concentration of fructosamine was (mean +/- S.E.M., N = 9) 0.45 +/- 0.09 mmol/L and varied from 0.15 to 0.75 mmol/L. It was 3-12 times lower than in blood serum of healthy men. In semen of infertile men (N = 57) fructosamine was present only in 21% of the cases and its concentration was lower than in fertile men i.e. (mean +/- S.E.M., N = 12) 0.27 +/- 0.007 mmol/L. In bulls (N = 98) fructosamine was found in semen of 82% of animals. In fru+ semen samples the concentration of fructosamine was (mean +/- S.E.M., N = 80) 0.77 +/- 0.12 mmol/L and varied from 0.30 to 1.15 mmol/L. We did not find any correlation between the concentration of fructosamine on one hand, and that of fructose and glucose on the other hand, in either human or bull semen. The difference in the frequency of fructosamine appearance in semen of fertile and infertile men suggests that fructosamine may be in some way involved in the process of fertilisation.     

Content of iron and copper in the nuclei and induction of pH 9-labile lesions in L5178Y sublines inversely cross-sensitive to H2O2 and x-rays

Cells from the L5178Y murine lymphoma subline LY-R are twice as resistent to killing by ionizing radiation than the subline LY-S. In contrast, LY-R cells are more sensitive to killing by H₂O₂, the effect being more pronounced at 37 °C than 0 °C. Initial DNA damage after H₂O₂ treatment (both temperatures, 5 min) has been estimated by the comet assay (single-cell gel electrophoresis) and fluorescent halo technique. According to both methods, the initial damage is significantly higher in LY-R cells, particularly that inflicted at O °C. Differences between DNA unwinding and rewinding abilities at pH 9 and 6.9 (estimated by the fluorescent halo technique) point to a considerable difference in pH-9-labile damage between the sublines, as observed previously for x-irradiated cells (Kapiszewska et al. 1992). In contrast to findings with x-irradiated cells, however, after H₂O₂ treatment this damage is more extensive in LY-R cells than in LY-S cells. Thus, the initial pH-9-labile damage corresponds to the pattern of sensitivity to H₂O₂ and x-rays. We suggest that this is caused by different proportions of cuprous and ferric ions found in the nuclei of LY sublines and by the different ability of these ions to react with H₂O₂ and water radiolysis products. The copper/iron ratio in the nucleus is 1.31 in LY-R cells and 4.84 in LY-S cells.     

Changes in blood level of catecholamines during arterial blood pressure rise induced with sciatic nerve stimulation

In experiments on rabbits and dogs it was demonstrated that electrical stimulation of the centripetal fibres of the cut sciatic nerve causing a rise of the arterial blood pressure produced a significant increase in the plasma levels of adrenaline and noradrenaline. This effect was not observed in animals with sympathetic system blockade caused by administration of reserpine. These observations indicate that pressure increase after sciatic nerve stimulation is due to stimulation of the adrenergic system.     

Familial translocation t(1p-;21q+) associated with Down's syndrome

Summary Familial occurrence of 1/21 translocation in connection with trisomy 21 was described. The possibilities of inheritance of further chromosome rearrangements arising during the gametogenesis of persons with this translocation were considered.     

Differences in the effects of vasopressin and oxytocin on rabbit myometrial activity and a possible mediation of prostaglandins

Uterine responses to vasopressin and oxytocin were monitored in non-pregnant and 3- or 6-8-day-pregnant rabbits by recording the intrauterine pressure. Oxytocin stimulated uterine activity in all groups, but the effect of vasopressin was stimulatory in non-pregnant animals, inhibitory in those 3 days post coitum and weakly stimulatory in those later in pregnancy. Inhibition of prostaglandin (PG) synthesis, by the administration of indomethacin, reduced the spontaneous uterine activity as well as the responses to oxytocin and vasopressin in the non-pregnant rabbits, but had little effect in the pregnant animals. During infusion of PGF-2alpha, PGE-1 or PGE-2 in 6-8-day-pregnant rabbits, the stimulatory response to vasopressin, although slight before the infusion, was inhibited whereas the stimulatory response to oxytocin remained virtually unchanged. The results suggest that vasopressin and oxytocin under certain hormonal conditions, are able to activated the uterine contractions by mechanisms in which the involvement of PG is not obligatory.