Towards the mechanism and comparative effect of diphenyl diselenide, diphenyl ditelluride and ebselen under various pathophysiological conditions in rat's kidney preparation

As an extension of our previous work we not only evaluated the relationship between acidosis and lipid peroxidation in rat's kidney homogenate, but also determined for the first time the potential anti-oxidant activity of diphenyl diselenide, diphenyl ditelluride and ebselen at a range of pH values (7.4–5.4). Because of the pH dependency of iron redox cycling, pH and iron need to be well controlled and for the reason we tested a number of pH values (from 7.4 to 5.4) to get a closer idea about the role of iron under various pathological conditions. Acidosis increased rate of lipid peroxidation in the absence Fe (II) in kidney homogenates especially at pH 5.4. This higher extent of lipid peroxidation can be explained by; the mobilized iron which may come from reserves where it is weakly bound. Addition of iron (Fe) chelator desferoxamine (DFO) to reaction medium completely inhibited the peroxidation processes at all studied pH values including acidic values (5.8–5.4). In the presence of Fe (II) acidosis also enhanced detrimental effect of Fe (II) especially at pH (6.4–5.4). Diphenyl diselenide significantly protected lipid peroxidation at all studied pH values, while ebselen offered only a small statistically non-significant protection. The highest anti-oxidant potency was observed for diphenyl ditelluride. These differences in potencies were explained by the mode of action of these compounds using their catalytic anti-oxidant cycles. However, changing the pH of the reaction medium did not alter the anti-oxidant activity of the tested compounds. This study provides evidence for acidosis catalyzed oxidative stress in kidney homogenate and for the first time anti-oxidant potential of diphenyl diselenide and diphenyl ditelluride not only at physiological pH but also at a range of acidic values.     

Intraspinal Tumors in Children

Thirty cases of intraspinal neoplasms occurring during the first two decades of life are reviewed. Histologic examination showed 13 of these to be astrocytomas, 6 neuroblastomas, 5 sarcomas, 3 ependymomas, 2 neurofibromas and 1 a schwannoma. Orthopedic deformities developed or worsened in 60 percent of patients surviving longer than a year after diagnosis. In five patients some form of endocrine deficiency developed after irradiation. For treatment of radiosensitive extradural malignant lesions, biopsy followed by irradiation is advocated.     

Co-segregation of a gene encoding a deletion ligand for Tcrb-V3+ T cells with Mtv-3

A gene encoding the endogenous superantigen Mls^c, which deletes Tcrb-V3⁺ T cells in the NOD inbred mouse strain, was found to co-segregate with Mtv-3 on chromosome 11. This identifies a fourth gene encoding a deletion ligand for Tcrb-V3⁺ T cells and extends recently published observations in support of the hypothesis that a number of endogenous superantigens are the products of Mtv proviruses. Address correspondence and offprint requests to : K. Tomonari.     

Xanthine oxidase,an indicator of secretory differentiation in mammary cells

Elevated levels of xanthine oxidase were found in (1) lactating mouse mammary glands, compared with virgin and midpregnant glands; and (2) primary mouse mammary cells cultured on floating collagen gels, compared with non-secretory cells on attached gels. In primary culture, increase in xanthine oxidase activity above a basal level coincided with secretory activity as measured by casein production; intracellular levels of casein and xanthine oxidase showed a high degree of correspondence. It is suggested that xanthine oxidase levels can be used as an indicator of in vivo and in vitro secretory differentiation in mammary epithelial cells.     

Two major classes of mitogen-reactive B lymphocytes defined by life span

The relative numbers of short- and long-lived mitogen-reactive B cells in the peripheral pool were evaluated by studying the decay of lipopolysaccharide (LPS)-reactive B lymphocytes in LPS nonresponder, histocompatible hosts for periods of up to 3 wk after cell transfer. The results obtained demonstrate the existence of two major classes of mitogen-reactive B cells defined by life span. The "short-lived" cell component comprises about 80 to 90% of the reactive cells and decays with a life expectancy of 18 to 24 hr. The long-lived cell component, with life expectancies of 10 to 20 days, comprises about 10 to 20% of the reactive cells and is preferentially enriched in circulating B cells. The present ratio for short- and long-lived B cells implies a highly dynamic state for the immune system which must be advantageous in the selection of available repertoires.