Iodine accumulation by the nephridia ofSipunculus (Sipuncula)

Résumé La détermination du contenu d'iode dans les différents organes des espèces du genreSipunculus (Sipuncula) a montré que les néphridies présentent la plus haute concentration de cette substance, ensuite vient l'intestin et la trompe. La forte accumulation d'iode dans les néphridies laisse supposer que ces organes sont responsables du métabolisme des iodoprotéines dans ce groupe d'Invertébrés.     

Fluorescence of indole derivatives

Zusammenfassung Die Verwendung von 1N Natronlauge und Essigsäureanhydrid bei der Bestimmung von Indolderivaten mit Hilfe der Fluoreszenzmethode erlaubt eine gute Differenzierung zwischen 5-Methoxyindolderivaten (z.B. Melatonin) und anderen Indolen. Versuche zur Verwendung der neuen Methode in biologischem Material, z.B. Epiphysenschnitten, sind im Gange.     

Alkaline phosphatase binds to collagen; a hypothesis on the mechanism of extravesicular mineralization in epiphyseal cartilage

Affinity chromatography on Sepharose 4B-collagen gels was used to test the affinity of alkaline phosphatase for collagen. Results indicate that alkaline phosphatase of preosseous cartilage binds to collagen probably by electrostatic interactions, this interaction is inhibited by proteoglycan subunits. These results suggest that, in vivo, the formation of a collagen-alkaline phosphatase complex may be a step of the process leading to cartilage calcification.     

Studies on GABA accumulation induced byγ-glutamyl-hydrazide in regions of rat brain following treatment with a tyrosine hydroxylase inhibitor and 6-hydroxy-dopamine

Summary Reduction of DA receptor activity via depletion of DA stores does not seem to influence GABA turnover in the forebrain and in the DA cell body rich region of the midbrain.This work was supported by a grant (MH25504-03) from the National Institute of Health, USA, and by Magn. Bergvalls Stiftelse and Funds from the Karolinska Institute, Stockholm, Sweden.     

Exchange of terminal portions of X- and Y-chromosomal short arms in human XX males

In most human 'XX males', DNA sequences normally found on Yp, the short arm of the Y chromosome, are present on Xp, the short arm of the X chromosome. To establish whether this transfer involves a terminal portion of Yp, and whether a terminal portion of Xp is lost in the process, we followed the inheritance of pseudoautosomal restriction fragment length polymorphisms in two XX-male families. One XX male apparently inherited the entire pseudoautosomal region of his father's Y chromosome and no part of the pseudoautosomal region of his father's X chromosome. The second XX male also inherited the entire pseudoautosomal region of his father's Y, but in addition inherited a proximal portion of the pseudoautosomal region of his father's X. These findings argue that XX males result from the transfer of a terminal portion of Yp onto Xp in exchange for a terminal portion of Xp (ref. 7). This implies that the testis-determining factor gene (TDF) maps distally in the strictly sex-linked portion of Yp, near the pseudoautosomal domain. The XX males described here appear to result from single (and, at least in the second case, unequal) crossovers proximal to the pseudoautosomal region on Yp and proximal to or within the pseudoautosomal region on Xp.     

The signal transducing system coupled to serotonin-S2 receptors

The signal transducing system coupled to the serotonin-S2 receptor on platelets involves metabolism of inositol-containing phospholipid, elevation of intracellular free Ca2+ and activation of protein kinase C. Evidence for coupling of the serotonin-S2 receptor to the same signal transducing system in brain and smooth muscle tissue is reviewed.     

Cadmium-induced lipofuscins and effect of zinc on hepatopancreas cells inIdotea baltica

Histological investigation revealed cadmium-induced lipofuscin formation in hepatopancreatic cells of the crustacean isopod,Idotea baltica. A comparison of lipofuscin induction by cadmium and by copper showed that cadmium has a weaker peroxidative action than copper. The effect of cadmium was reduced by the simultaneous presence of zinc, which on its own was ineffective in lipofuscin induction. A tentative explantation of the interactive effects of these materials is suggested.