Effect of dipyridamole on human platelet phospholipids

Summary The effect of dipyridamole on platelet phospholipids has been studied. After the platelet incubation with dipyridamole, a 38% reduction in the concentration of the sphingomyelin and a 21% increase in phosphatidyl choline were produced.     

Pyrogen fever in rabbits pretreated with p-chlorophenylalanine or 5, 6-dihydroxytryptamine.

The hyperthermic effect of a bacterial pyrogen has been studied in rabbits pretreated or not with p-chlorophenylalanine or 5, 6-dihydroxytryptamine. The results obtained indicate that a selective reduction of cerebral 5-hydroxytryptamine levels by these drugs do not significantly affect pyrogen hypertermia.     

Effect of X-537A on the phosphorylated protein in sarcoplasmic reticulum vesicles

Summary The effect of the antibiotic X-537A on the phosphorylated ATPase (EP) was investigated. The results show that X-537A depresses the level of EP which is dependent on the Ca²⁺ gradient, while the Ca²⁺-independent EP is not affected. Acknowledgments. This work was supported by grants from the Instituto de Alta Cultura of the Portuguese Ministry of Education (No. CB/2) and the Calouste Gulbenkian Foundation.     

Does an inhibitor of mitochondrial adenylate kinase also affect oxidative phosphorylation?

Summary Adenylate kinase activity of intact mitochondria is strongly inhibited by Ap₅A, i.e.p ¹,p ⁵-Di (adenosine-5-) pentaphosphate, whereas oxidative phosphorylation is not affected. Therefore, Ap₅A is a useful tool to distinguish between oxidative and non oxidative ATP generating reactions.Acknowledgment. The generous support of Prof. Dr.Walther Lamprecht is gratefully acknowledged. J. L. thanks the Stipendienfonds des Verbandes der Chemische Industrie for a scholarship.     

Blood plasma investigations by resonance raman spectroscopy: Detection of carotenoid pigments

Summary Using Raman spectroscopy, we demonstrate that low levels of -carotene, lycopene, and xanthophyll give rise to resonance enhanced bands in blood plasma. These results explain the significance of previously unidentified spectral maxima which have been related to the state of health of the blood donor.     

Struktur-Wirkungsbeziehungen beim menschlichen Calcitonin. III. Die biologische Aktivität verkürzter oder an den Kettenenden modifizierter,synthetischer analoger

Summary Assays of 8 synthetic analogues of human calcitonin in rats showed that their hypocalcaemic activity was drastically reduced by deletion of the C-terminal amide group, chain-shortening or opening of the disulphide ring, but unaffected or enhanced by modification of the N-terminal amino group.

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II. vgl.R. Maier, B. Kamber, B. Riniker andW. Rittel, Hormon. Metab. Res.7, 511 (1975).

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Die hier verwendete, abgekürzte Schreibweise für Peptide folgt den Empfehlungen der IUPAC-IUB Kommission für Biochemische Nomenklatur, J.B.C.247, 977 (1972). Weitere Abkürzungen: HCT, Human-Calcitonin; PCT, Schweinecalcitonin; Bmp, -Mercaptopropionsäure (Desaminocystein); NMet, Normethionin (S-Methylcystein); -OMe, Methylester.     

4-Isothiocyanato-4′-nitrodiphenylamine (C9333-Go/CGP 4540) an anthelminthic with an unusual spectrum of activity against intestinal nematodes,filariae and schistosomes

Summary 4-isothiocyanato-4-nitrodiphenylamine was found to possess activity against intestinal nematodes in mice, against schistosomes in various hosts including primates and against two filarial species in the mongolian jird. Upon administration in a single oral dose it is equally effective againstS. haematobium, S. mansoni andS. japonicum.     

Sur l'inversion de l'action hypertensive de la prostaglandine F2α, chez le rat

Summary In normal rats, prostaglandin F₂ is a potent vasoconstrictor. The corresponding systemic hypertension is progressively attenuated by tachyphylaxis, revealing a longlasting fall of blood pressure. Tachyphylaxis is accelerated by previous injection of arachidonic acid and bradykinin. The vasodepressive activity of PGF₂ is inhibited by indomethacin.

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Nous remercions vivement le docteurPike (Upjohn, Kalamazoo) qui nous a fourni gracieusement ces prostaglandines.     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.