Reversal of metamorphosis in mealy bugs treated with juvenile hormone-active insect growth regulator

Summary Anal pore-plates are a typical adult characteristic of male mealy bugs. Nymphs treated with a juvenile hormone-active insect growth regulator moult several times into intermediary forms between nymph and adult. The number of the anal pores is reduced during each of these supernumerary moults.Presented at the XVth International Congress of Entomology, Washington DC 1976.Acknowledgments. We wish to express our thanks to Sir Vincent B. Wigglesworth and Mr M. Gruber for revision of the text and to Mr M. Dickenmann and Mrs B. Mühlemann for technical assistance.     

The effects of acetylation on the binding region of cartilage proteoglycans to hyaluronic acid

Summary Proteoglycans in cartilage are found as aggregates and as monomers. Evidence has been obtained indicating that hyaluronic acid, normally present in this tissue, binds together monomers into large molecular weight aggregates. In this investigation, the interacting region of the protein backbone has been studied. The results unequivocally demonstrated that the epsilon amino groups of lysine are involved in hyaluronic acid binding to proteoglycans and that their blocking by acetylation either prevents reaggregation or disaggregates the high mol. w aggregates.Supported by a grant from the Consiglio Nazionale delle Ricerche, Rome, Italy, and U. S. P. H. S., grants DE-02670 and HL 11310.     

Prostaglandin production by human polymorphonuclear leucocytes during phagocytosis in vitro

Summary Human polymorphonuclear leukocytes were found to be able to synthetize and release substantial amounts of PGE₂, when stimulated by a phagocytic stimulus such as zymosan particles coated with complement. Hydrocortisone, at a concentration of 10^–5 M, which proved to be effective in other biological systems, failed to inhibit phagocytosis and PG release.     

Changes in gastro-intestinal serotonin content associated with fasting and satiation

Summary Rats fasted for 24 h were fed for 3 h, after whith time food was removed. Food intake decreased serotonin levels in the stomach and duodenum by 30 and 40%, respectively. These changes persisted for about 3 h. Food intake did not change tryptophan content in the stomach, while, in the duodenum, tryptophan level rose by 100% at the end of the feeding period and remained elevated for about 9 h.     

Increased relative growth rate of normal rat cells in vitro with crocetin

Summary The carotenoid crocetin (earlier found to increase relative growth of Walker 256 tumor cells and their radiosensitivity), is shown to increase the relative growth of normal Sprague-Dawley rat muscle derived cells in vitro, presumably by increasing oxygen transport.     

The effect of methaqualone on prenatal development in the rat

Summary Methaqualone treatment of pregnant rats in doses of 100–200 mg/kg day produces resorption and a series of anomalies whose incidence increases with the dose-level employed.Acknowledgment. Supported by the National Research Council of Canada, grant No. A0292. Methaqualone was generously supplied by W. H. Rorer, Canada, Ltd.     

14-3-2 protein in rat brain synapses

Summary The distribution of the 14-3-2 protein in rat brain synapses was studied by immuno electron microscopy. The protein was localized to the postsynaptic web and to the postsynaptic membrane, but was also prominent both in the presynaptic membrane and in the presynaptic densities. No significant activity was observed in the synaptic vesicles.Acknowledgments. Our sincere thanks to Mrs Ulla Svedin, Eng., for skilled technical assistance. This work was supported by grants from the Swedish Medical Research Council, the Medical Faculty of Göteborg, Tore Nilson's Foundation for Medical Research and by the Swedish-Italian Group of Neurobiology. A. G. received financial support from Consiglio Nazionale delle Ricerche (CNR, ROME).     

Lysosomal enzyme release associated with the invasion of rat liver by Novikoff hepatoma

Summary The lysosomes of both Novikoff hepatoma and liver from Novikoff hepatoma-bearing rats were found to be relatively intact structurally, lower in acid phosphatase activity, greatly depleted in number but with nearly normal membrane integrity when compared with normal liver.Acknowledgments. We thank Dr Ellen Rasch for her valued advice and interest in the project. We are grateful to M. P. Shaw for help with the acid phosphatase assay.     

Comparison of bicyclic phosphorous esters with bicuculline and picrotoxin as antagonists of presynaptic inhibition in the rat cuneate nucleus

Summary The effects of 2 of a series of bicyclic phosphorous esters, the ethyl (EPTBO) and isopropyl (IPTBO) compounds, were compared with those of the GABA antagonists, picrotoxin and bicuculline, on presynaptic inhibition in the rat cuneate nucleus. Both EPTBO and IPTBO were found to be effective, reversible antagonists of presynaptic inhibition, with IPTBO approximately 10 times more potent than EPTBO and equipotent with bicuculline, EPTBO equipotent with picrotoxin.The authors are grateful to Dr J. F. Collins, Department of Chemistry, Sir John Cass School of Science and Technology, 31 Jewry Street, London, for the gift of bicyclic phosphorous esters.     

Ultrastructural autoradiographic study of blast cells in the mouse thymus Interest for radioleukemia research

Summary Ultrastructural autoradiographic studies of mouse thymic blast cells after H3 Tdr injection show that their fine nuclear structure is related to their position in the cell cycle. The variations in the composition of the subcapsular blast cell population during radiation-induced leukemogenesis indicate kinetic changes in thymic lymphopoiesis, which are probably due to the oncogenic process.