The potential independent series resistance in rat ventricular fibres

Summary Current clamp experiments performed in rat ventricular fibres revealed the presence of a resistance Rs (between 14.5 and 15.5 K) in series with the membrane capacity. Rs behaved as a lumped resistance and its value remained constant throught the action potential repolarization phase.This work was supported in part by grants from D. G. R. S. T. and C. N. R. S.     

Inhibited hormonal induction of hepatic phosphoenolpyruvate carboxykinase in poly I∶C treated mice,an endotoxin-like glucocorticoid antagonism

Summary Corticosteroid induction of mouse hepatic phosphoenolpyruvate carboxykinase was inhibited by prior injection of poly IC. Mice challenged with a lethal dose of endotoxin 4 h after administration of poly IC could not be protected by a concurrent injection of hydrocortisone.This investigation was supported by U. S. Public Health Service research grant No. AI-10087 from the National Institute of Allergy and Infectious Diseases.     

Minor nitrogenous sesquiterpenes from the marine spongeAxinella cannabina. A hypothesis for the biogenesis of the spiro-axane skeleton

Summary Three nitrogenous sesquiterpenoids (4–6), possessing an isocyanide, isothiocyanate or formylamino function, have been isolated from the marine spongeAxinella cannabina. The proposed structures were based on interpretation of spectral data including 2D-NMR techniques and chemical evidence. A plausible pathway for the biogenesis of these compounds and the co-occurring spiro-axane (1–3) metabolites is proposed.Work supported by C.N.R. (Progetto Finalizzato Chimica Fine e Secondaria and by MPI Italy.     

Predominant expression of σ and ε globin genes in human leukemia K-562(S6) variant cell line

Summary In the human leukemia K-562(S6) cell line (a) the accumulation ofa-globin chains is low or absent, (b) -globin gene expression is correlated with expression of -chains and (c) the genes responsible for the terminal cell division are not operated within 8–12 cell cycles, while K-562 (S6) cells are fully induced to erythroid differentiation.This work was supported by grants from the Italian National Research Council (C.N.R.) G. R. is a recipient of a fellowship from the National Committee for Nuclear Energy, Rome. Address for reprint requests: R. G., Centro di Studi Biochimici, Via L. Borsari 46, I-44100 Ferrara.     

Phytosterols from pressmud residue obtained after methanogenic fermentation

Summary Pressmud, a sugar factory waste, was fermented with methanogenic bacteria in an anaerobic fermenter for 40 days at 31±2°C. The pressmud residue obtained after fermentation was used as a source for the extraction of phytosterols. The anaerobic digestion degraded the organic matter and resulted in enrichment of phytosterols from 0.33% in the pressmud to 3.05% in the residue. Refluxing of 100 g of residue with benzene, petroleum ether, and ethanolic KOH (1051) yielded 8 g of soft cake, which on further fractionation with methylcyanide and isopropanol gave three fractions: 1) a crude mixture of phytosterols, 2) resin, and 3) undigested organic matter. The crude mixture of phytosterols after purification on neutral alumina followed by GLC analysis resulted in the separation of 68.7% of -sitosterol, 18.4% of stigmasterol and 12.9% of campesterol and brassicasterol together. Phytosterols were extracted more easily from fermented than from unfermented samples, because of biodegration of lipophilic compounds by the methanogenic bacteria.Acknowledgments. S.K.S. and J.C.S. are thankful to the authorities of the U.G.C., New Delhi, for the award of Teacher-fellowships. R.C.S., R.A.K.S. and D.K.M. are thankful to the authorities of the C.S.I.R., New Delhi, for providing R.A., S.R.F., and J.R.F., respectively. Reprint request to S.N.M.     

Theoretical prediction of carcinogenicity: Quasi-quantification by quasi-valence. A reply to V. Veljkovic and D. I. Lalovic

Summary We have shown the recently proposed method for prediction of carcinogenicity by average quasi-valence number to be neither a good predictor of carcinogenicity, nor of non-carcinogenicity.Grants to Edward J. Klekowski Jr from the U.S. National Science Foundation and from the office of Water Resources Research, U.S. Department of the Interior under the Water Resources Research Act of 1964, as amended, supported this research.     

Relationship between chlorophyll a content and protein content of invertebrate symbioses with algae or chloroplasts

Summary The chlorophyll a and protein contents of invertebrates containing autotrophic symbionts are indices of symbiont and host biomass, respectively, and the chlorophyll a content per unit protein is a good measure of symbiont: host ratio. For three different associations, the chlorophyll a content per unit protein is 0.01–0.02 g g^–1.The hydra andE. viridis were provided by M. H. Christopher and J. R. Turner. I thank Professor D. C. Smith, Dr J. B. Searle and Dr T. A. V. Rees for the valuable comments on drafts of this paper. This work was supported by research grants from S.E.R.C.     

Different effects of syntheticΔ 9-tetrahydrocannabinol and cannabis extract on steroid metabolism in male rats

Summary Repeated oral administration of cannabis extract as well as synthetic ⁹-tetrahydrocannabinol to male rats produced significant changes in excretion of androgenic steroids and their metabolites as detectable in blood and urine. Cannabis extracts were found to be significantly more active than the mixtures containing same amounts of synthetic cannabinoids.Acknowledgment. This work was supported by Grant No. R01-DA-00507 from the National Institute on Drug Abuse, US Public Health Service.     

Studies onxHaynaldoticum sardoum Meletti et Onnis metabolism during seed life-span: α-amylase and glutamate decarboxylase activity

Summary Embryo GAD activity and -amylase in the endosperm of 2 different physiological lines (CP; CV) ofxHaynaldoticum sardoum Meletti et Onnis were evaluated and different stages of seed ripening and progressively older seeds were examined. Results concerning GAD activity during ripening show differences between CP and CV seeds, the former being more active. In the ageing seeds, the GAD remains constant (CP is twice as much as CV) up to 4th year and greatly decreases at the 5th. The -amylase activity is fairly constant during ripening in CV endosperm and increases in CP: at the fully-ripe stage, both show similar values. During seed ageing, the activity decreases progressively in CV endosperm while, in CP, values are greater but fairly constant. The results are discussed in connection with dormancy and the different physiological ageing of seeds.This work was supported by a grant from the Consiglio Nazionale delle Ricerche (Rome, Italy).Acknowledgments. The authors wish to thank Mr F. Saviozzi, Mr V. Sbrana and Mr R. Bertini for their expert technical assistance.     

Immunogenicity of fatty acid anilides in rabbits and the pathogenesis of the Spanish toxic oil syndrome

Summary Fatty acid anilides, the major xenobiotic found in the cooking oils responsible for the Spanish toxic oil syndrome, are immunogenic for rabbits as ascertained by a skin test reaction, the characterization of specific antibodies against anilides and the immunofluorescent detection of anilide dependent antigens in tissue slices from treated animals.Acknowledgments. This work was supported by a grant from the Fondo de Investigaciones Sanitarias to the C.S.I.C. Programme on Toxic Oil Syndrome. We are indebted to Dr M. Studt and Dr E. Fernández-Alvarez, from the National Center for Organic Chemistry, C.S.I.C., for kindly providing the synthetic fatty acid anilides. We also wish to thank Prof. C. Gitler for helpful discussion.     

The role of zinc in regulating tabtoxin production

Summary The phytotoxin, tabtoxinine--lactam, is produced by severalPseudomonas syringae pathovars if adequate Zn is available, otherwise its biologically inactive form, tabtoxin, is produced. The Zn is required for the action of a peptidase which cleaves tabtoxin, releasing the toxic -lactam.This research was supported in part by U.S.D.A. Competitive Research Grant No. 83-CRCR-1-1201.     

Effect of halogenmethylenebisphosphonates on bone cells in culture and on bone resorption in vivo

Summary Dihalogenmethylenebisphosphonates increase alkaline phosphatase activity and fatty acid oxidation in calvaria cells in culture (Cl₂MBP>Br₂MBPF₂MBP). The monohalogen C1MBP and the non-halogenated analogues are less active on phosphatase and inactive on or inhibitory towards fatty acid oxidation. The three dihalogenbisphosphonates and C1MBP inhibit bone resorption in vivo, Cl₂MBP most strongly.Acknowledgments. We thank Miss M.-L. Aebersold, Miss J. Portenier, Mrs I. Tschudi and Mrs Ch. Marti for their skilled technical assistance. This work has been supported by the Swiss National Science Foundation (grant 3.937.82), by the Procter & Gamble Company, Cincinnati, USA, by the Istituto Gentili S.p.A., Pisa, Italy, and by the Ausbildungs- und Förderungsfonds der Arbeitsgemeinschaft für Osteosynthese (AO), Chur, Switzerland.     

Cytogenetic effects of delta-9-tetrahydrocannabinol (Δ 9-THC) on hamster bone marrow

Summary Single s.c. injections of 10 or 1000 mg/kg of ⁹-THC did not induce discernable chromosomal damage but caused significant mitotic inhibition in the bone marrow of Syrian hamsters.Acknowledgments. The authors which to thank Mr R.H. Graham, Department of National Health and Welfare, Health Protection Branch, for the generous supply of ⁹-THC. This research was supported by a grant to Dr M.G. Joneja from the Department of National Health and Welfare.     

Binding of aflatoxins B1 and G1 to human serum proteins

Zusammenfassung In vitro Experimente mit¹⁴C-markiertem, gereinigtem Aflatoxin zur Untersuchung der Bindung von Aflatoxin B₁ und G₁ an verschiedene Serumproteine ergaben, dass Aflatoxin B₁ hauptsächlich mit-Globulin, G₁ dagegen vorwiegend mit Albumin bindet.

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This work was supported by part by a grant from the China Medical Board of New York, Inc., and was performed during one of us (S.S.L.) received a class C. research award from the National Science Council, Republic of China.     

Glischropus tylopus,the first known old-world bat with an X-autosome translocation

Summary Glischropus tylopus shows an X-autosome translocation in which a small acrocentric chromosome has been transferred to the X. The diploid number is 30 for the females and 31 for the males. RBG banding shows that in the late replicating X of the female only the original X replicates late, the autosomal part replicates early, showing the same pattern as the corresponding autosomal Y₂ of the male. In the X chromosome, a heterochromatic band separates the autosomal from the gonosomal sequences.23 January 1987I am very grateful to Prof. R.A. Pfeiffer for giving me the opportunity to work at the Department of Human Genetics.My stay in Malaysia was supported by a grant of the DAAD.     

Synthesis of a Pentapeptide by theMerrifield method

Résumé La synthèse du pentapeptide His-Phe-Arg-Trp-Gly a été réalisée par la méthode en phase solide deMerrifield. L'Arginine a été introduite sans protection du groupe guanidinium; de même le noyau imidazole de l'Histidine n'a pas été protégé.

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This work was supported by the Grant No. 1341 of the Institut pour l'Encouragement à la Recherche Scientifique dans l'Industrie et l'Agriculture (I.R.S.I.A.).     

Is the renal vasodilatation induced byβ-adrenoceptor stimulants in the dog mediated through dopamine receptor?

Summary In chloralose-anaesthetized dogs the renal vasodilator effect of isoprenaline is depressed by blockade of either dopamine or -adrenoceptors but the renal vasodilator effect of dopamine is depressed only by blockade of dopamine receptors. This suggests that the vasodilatation induced by -stimulants within the canine kidney is due in part to activation of dopamine receptors.This study was supported by the Life Insurance Medical Research Fund of Australia and New Zealand and by the Australian Kidney Foundation.We thank Mr S. Marshall for technical assistance.     

Action des différentes formes actives de la vitamine A sur le mécanisme immunitaire chez le rat

Summary In this work, we have studied the role of different active forms of vitamin A considered as adjuvant of the immune mechanism in the rat. We also pointed out the adjuvant effect of retinol and retinal in comparison with the other active components of that vitamin with the bovine -globulin which is not an immunogenic antigen in itself in the control rat. Despite the fact that vitamin A has no antigenecity, it still possess an extrinsic adjuvanticity in presence of bovine -globulin. The degree of the immune response is increased.

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Action des différentes formes actives de la vitamine A sur le mécanisme immunitaire chez le rat

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Supporté par le C.N.R.S., Liban.     

Enantiomeric cannabinoids: stereospecificity of psychotropic activity

Summary The 1,1-dimethylheptyl homolog of (–)-(3R,4R)-7-hydroxy-delta-6-tetrahydrocannabinol (compoundII) is highly psychotropic in mice, rats and pigeons. The (+)-(3S,4S) enantiomer (III) was found to be psychotropically inactive at doses up to several thousand times those of the ED₅₀ of (II).We thank Dr A. Breuer and Mrs H. Amsalem for help with the syntheses. The research reported above was supported in Tucson by NIH grant NS 15441; in Uppsala by grants from the Swedish Medical Research Council (5757) and the Swedish Council for the Planning and Coordination of Research (84/2082); in Jerusalem by the Szold Foundation.Presented in part at a meeting at the US National Institute on Drug Abuse, Washington, D.C., October 1986, see NIDA Research Monographs79 (1987) 15.     

Sirenids: a family of polyploid urodeles?

Riassunto I tre Sirenidi viventi hanno 46, 52 e 64 cromosomi; il corredo diS. lacertina sembra tetraploide (4n=52). Viene fatta l'ipotesi che anche i corredi delle altre due specie derivino per (allo-)poliploidia da corredi a minor numero cromosomico, come si ritrovano nelle famiglie superiori dell'Ordine.

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Research carried out through a contribution from the C.N.R.