Effect of AD6 (8-monochloro-3-beta-diethylamino-ethyl-4-methyl-7-ethoxycarbonylme tho xy coumarin) on cyclic nucleotide phosphodiesterases in human platelets

The effect of AD6 (8-monochloro-3-beta-diethylamino-ethyl-4-methyl-7-ethoxycarbonylmeth oxy coumarin), an inhibitor of platelet aggregation, on cyclic nucleotide metabolism was investigated. AD6 inhibited selectively human platelet cyclic GMP phosphodiesterase, which was separated from cyclic AMP phosphodiesterase by DEAE-cellulose chromatography. Addition of AD6 to washed platelets increased cyclic GMP levels significantly in two minutes. These results could be useful in elucidating the action of AD6 on intact platelets.     

The influence of sodium transport on glucose transport by anin vitro intestinal preparation

Riassunto Vengono riportati i dati ottenuti sul trasporto di sodio e di glucosio attraverso l'intestino isolato di ratto, perfuso con soluzioni isotoniche a diverso contenuto di sodio. Da questi dati appare che non solo il trasporto di sodio dipende dalla concentrazione di sodio nel liquido mucosale, ma anche il transporto di glucosio. Si prospetta l'ipotesi, inoltre, che il passaggio di sodio dalla mucosa alla sierosa sia necessario sopratutto per il trasferimento del glucosio dalle cellule al liquido serosale.     

High nuclear DNA content in nervus terminalis ganglion cells ofScorpaena porcus

Zusammenfassung Gewisse Ganglien-Zellen vonScorpaena porcus weisen einen DNA-Gehalt auf, der 32 bis 64 mal höher ist als derjenige von normalen Neuronen.

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Research supported by a CNR grant.     

Liver phospholipides after carbon tetrachloride intoxication in rats

Riassunto Dopo avvelenamento acuto di ratti con CCl₄ somministrato con dose singola per via orale l'incorporazione in vivo di P³² nei fosfolipidi del fegato è alterata precocemente. A 80 min dalla somministrazione del tossico si osserva un forte aumento delle P³²-lisolecitine, mentre risulta bloccata la sintesi di acido fosfatidico.     

Diabete da allossana

Summary Insulin deficiency induced by alloxan treatment reduces cocarboxylase activity in the liver of rat. Such enzymatic activity, however, is brought back to the normal speed by fructose injection. It is suggested that fructose, the turn-over of which in diabetic animals is normal, may be capable of furthering the synthesis of A.T.P. and enhancing phosphorylation of thiamine into cocarboxylase.

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Nota N^o 1; Rapporti fra utilizzatione del fruttosio ed attività cocarbossilasica.     

NMR structures of the C-terminal end of human complement serine protease C1s

Synthetic peptides derived from the C-terminal end of the human complement serine protease C1s were analysed by circular dichroism and nuclear magnetic resonance (NMR) spectroscopy. Circular dichroism indicates that peptides 656-673 and 653-673 are essentially unstructured in water and undergo a coil-to-helix transition in the presence of increasing concentrations of trifluoroethanol. Two-dimensional NMR analyses performed in water/trifluoroethanol solutions provide evidence for the occurrence of a regular α-helix extending from Trp659 to Ser668 (peptide 656-673), and from Tyr656 to Ser668 (peptide 653-673), the C-terminal segment of both peptides remaining unstructured under the conditions used. Based on these and other observations, we propose that the serine protease domain of C1s ends in a 13-residue α-helix (656Tyr-Ser668) followed by a five-residue C-terminal extension. The latter appears to be flexible and is probably locked within C1s through a salt bridge involving Glu672. Received 19 November 1997; accepted 24 November 1997     

Studies on the chemical constitution and sex pheromone activity of volatile substances emitted byDacus oleae

Summary Volatile substances from the females ofDacus oleae have been submitted to GLC-MS analysis and several components identified. E-6-nonen-1-ol and p-cymene displayed attractive and aphrodisiac effects in both laboratory and field experiments.Part of this work has been presented at the 4th International Congress of Pesticide Chemistry (IUPAC), Zurich, July 1978-Comm. III, 230 and at the 11th International Symposium on the Chemistry of Natural Products (IUPAC) Varna, September 1978.This work has been supported by the CNR, special ad hoc program Fitofarmaci e Fitoregolatori subproject 2.     

Hyperforin is a novel type of 5-lipoxygenase inhibitor with high efficacy in vivo

We previously showed that, in vitro, hyperforin from St. John’s wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B₄ formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.