Placental transfer of a human IgG2 monoclonal protein

Résumé Étude du passage transplacentaire à son enfant des sousclasses de l'IgG chez une femme atteinte d'une forme benigne de gammapathie monoclonale. Le transfer de la paraprotéine IgG2 L a été établi avec certitude. Il est très probable que les autres sous-classes sont également transferées. Comparée aux résultats publiés sur catabolisme de l'IgG chez l'adulte, la durée de vie de l'IgG total et de l'IgG2 est très longue chez l'enfant.     

The identification of dehydroretinol (vitamin A2) in human skin

Summary Vitamin A₂ has for the first time been identified in a human tissue and, in contrast to vitamin A₁, its concentration in the epidermis is markedly increased in a hyperkeratotic condition (Psoriasis vulgaris).Acknowledgments. The valuable discussions with Prof. I. Björk, Drs A. de Belder, C. Lindberg and J.B. Lee are gratefully acknowledged. Purified retinoids were generously supplied by F. Hoffmann-LaRoche Co. AG, Basle. This project was supported by grants from the Swedish Medical Research Council (B78-03x-05174), the Welander Foundation and the Tore Nilsson Fund.     

Ablation of cyclase-associated protein 2 (CAP2) leads to cardiomyopathy

Cyclase-associated proteins are highly conserved proteins that have a role in the regulation of actin dynamics. Higher eukaryotes have two isoforms, CAP1 and CAP2. To study the in vivo function of CAP2, we generated mice in which the CAP2 gene was inactivated by a gene-trap approach. Mutant mice showed a decrease in body weight and had a decreased survival rate. Further, they developed a severe cardiac defect marked by dilated cardiomyopathy (DCM) associated with drastic reduction in basal heart rate and prolongations in atrial and ventricular conduction times. Moreover, CAP2-deficient myofibrils exhibited reduced cooperativity of calcium-regulated force development. At the microscopic level, we observed disarrayed sarcomeres with development of fibrosis. We analyzed CAP2’s role in actin assembly and found that it sequesters G-actin and efficiently fragments filaments. This activity resides completely in its WASP homology domain. Thus CAP2 is an essential component of the myocardial sarcomere and is essential for physiological functioning of the cardiac system, and a deficiency leads to DCM and various cardiac defects.     

Potentiation of haemolysis by the combined action of phospholipase A and a basic peptide containing S-S-bonds (Viscotoxin B)

Zusammenfassung Viscotoxin B, ein basisches Peptid mit Disulfidgruppen, zeigt in der Hämolyse den gleichen synergistischen Effekt mit Phospholipase A wie der direkt lytische Faktor des Kobragiftes. Dieses Ergebnis stützt die Hypothese, dass Zellmembranen durch Reaktionen ihrer Protein-SH-Gruppen so verändert werden können, dass Phospholipase A sonst unzugängliche Membranphospholipide angreift.

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We thank MissAstrid Jörgensen for skilful technical assistance, and Dr.G. Samuelsson for viscotoxin B.     

Vasoactive intestinal peptide (VIP): specific receptors and adenylate cyclase activation in a human prolactin-secreting pituitary tumor]

Receptors for the Vasoactive Intestinal Peptide (VIP) were characterized in particles enriched in plasma membranes obtained from a human prolactin-secreting pituiatry tumor. Native VIP inhibited competitively the binding of 125I-VIP to the particles and stimulated cyclic AMP production; both these effects were observed at concentrations of VIP as low as 10(-11)-10(-10) M, which are compatible with VIP concentrations in the hypothalamopituitary portal blood.     

A specific protein in the genusRhynchosciara (Diptera,Sciaridae)

Summary Proteins immunologically related toRhynchosciara americana larval protein 10 occur in the hemolymph and ovaries of five different fly species of the genusRhynchosciara. Electrophoretic analyses showed these proteins to have a mol.wt similar to that of theR. americana protein 10 (43,000), e.g. theR. hollanderi protein 44,300, theR. milleri protein 45,500.     

Topography of soluble gliofibrillar protein (GFA) in aged human brain]

A great variation was observed in the amount of soluble GFA depending on the brain area. Large amounts were found in the chiasma and in the pons whereas the cortical grey matter was poor. It is suggested that soluble GFA represents a potentiality of defense of the nervous tissue.     

Isolation of a hypothalamic peptide with TRF (thyreotrophin releasing factor) activityin vitro

Zusammenfassung Die elektrophoretisch isolierte Fraktion des hypothalamischen Extraktes, die die adenohypophysären sauren Phosphatasenin vitro und die Sekretion des TSH aktiviert, wurde mittels Gel-Filtration an einer Sephadex G-25 Säule weiter gereinigt. Elektrochromatographische Analyse der gereinigten Fraktion zeigte, dass sie in nativem Zustand Ninhydrin-negativ ist und dass nach der sauren Hydrolyse folgende Aminosäuren aus ihr entstehen: Lysin, Serin, Glycin, Alanin, Asparagin, Glutamsäure, Valin, Isoleucin und Leucin. Dieselbe Fraktion erhöht die Sekretion des TSH aus Rattenhypophysein vitro. Die Fraktion enthält also wahrscheinlich den hypothalamischen Peptid, der die Sekretion des TSH aus der Hypophyse stimuliert (thyreotrophin releasing factor, TRF).