The effects of sodium and amiloride on the motility of the caudal epididymal spermatozoa of the rat

Summary The forward motility of the rat caudal epididymal spermatozoa has been studied in different Na⁺ concentrations. When spermatozoa were suspended in a completely Na⁺-free solution, the forward motility suffered a progressive fall and after 3 h was completely suppressed. This effect was fully reversible on resuspending the spermatozoa in a solution containing Na⁺. Amiloride caused a fall in motility and the effect was similar to that of Na⁺ removal. The inhibition by amiloride of the motility was concentration dependent and the dose response curve showed an IC₅₀-value of about 5×10^–5 M. The role of Na⁺ influx in the maintenance of sperm motility was discussed.This work was supported by the World Health Organization.The technical assistance of Mr C.M. Li and the gift of amiloride from Merck, Sharp and Dohme are gratefully acknowledged.     

Effects of arsenite and oxamate on the in vitro functional activity of estrogen-dominated rat uterine horns

Summary Arsenite but not oxamate produce in vitro a distinct depression of estrogen-dominated uterine motility, both in the absence of substrate as well as in the presence of exogenous glucose or lactate. The addition of oxamate to preparations suspended in a medium with lactate as the sole external substrate ameliorates the depression of uterine motility elicited by arsenite.This work has been supported by grants 6638 and 6294 from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.Senior Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.Junior Investigator of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina.     

Metabolism of amphibian spermatozoa in relation to their motility

Summary Bufo arenarum spermatozoa were able to sustain motility both under aerobic and anaerobic conditions. In aerobiosis, the oxygen consumption varies between 2.6 and 4.2 l O₂/10⁸ cells/h at 30°C. The synthesis of lactic acid by anaerobic spermatozoa demonstrated the existence of an active glycolytic pathway.This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas and the Latinoamerican Program of Human Reproduction (PLAMIRH), grant 34-95-2-75.     

Thyroxine administration and the uptake of amino acids by liver cell nucleolus,nucleus and cytoplasm,and by other cell types

Résumé L'administration de thyroxine cause une chute de l'incorporation de la phénylalanine-H³ et du tryptophane-H³ par divers organes, excepté le foie. Le cytoplasme et les noyaux des hépatocytes ont presenté une plus grande concentration de substance injectée.

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This investigation was supported by grants from Fundaçao de Amparo à Pesquisa do Estado de São Paulo, Rockefeller Foundation, and Conselho Nacional de Pesquisas.

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The help of Profs.L. C. U. Junqueira andC. P. Leblond as well as the technical assistance of MissE. Freymüller are acknowledged.     

Uptake from blood and conjugation of bilirubin by the intestinal Mucosa of Wistar,Gunn and hepatectomized rats

Resumen Se infundió bilirrubina no conjugada en tres grupos de ratas: normales, totalmente hepatectomizadas y Gunn homocigotas, observándose la aparición de bilirrubina conjugada en la mucosa intestinal de los dos primeros grupos. Dichos experimentos, confirmados con el uso de bilirrubina-¹⁴C, demuestran que la bilirrubina no conjugada sérica puede ser captada y conjugada por la mucosa intestinal de la rata.

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This work was supported in part by a grant from C.O.F.O.I.C., Pcia. de Santa Fe, República Argentina. We thank Mr.J. Rassero for his invaluable technical assistance.     

Effect of heat treatment on the ATPase activity of various sarcoplasmic reticulum preparations

Summary Ca²⁺-stimulated ATPase activity of sarcoplasmic reticulum (SR) preparations is activated after a short period of preincubation at temperatures between 40 and 45°C, but for temperatures higher than 48°C pronounced denaturation is observed. Heat denaturation is decreased if Mg²⁺ or K⁺ are present during heat treatment.Acknowledgments. This work was supported by research grants from Instituto de Alta Cultura (Grant No. CB/2) and the Calouste Gulbenkian Foundation. We are grateful to Drs.A. P. Carvalho andV. M. C. Madeira for many discussions and suggestions during the course of this work.     

Inhibition of mammalian acetylcholinesterase by phenylmethanesulfonyl fluoride

Resumen El fenilmentano sulfonil fluoro (FMSF) 4×10^–5 M inhibe a la acetilcolinesterasa (E. C. 3.1.1.7) de cerebro de rata en más de 50%, y 9×10^–4 M más de 90%. La constante de reacción inhibidor enzima es de 4.7×10² (1 mol^–1 min^–1). La colinesterasa (E. C. 3.1.1.8) de cerebro de rata es insensible a FMSF.

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Supported by NIMH Grant No. 1 RO3 MH 19125, by Comisión Nacional de Investigación Cientiffica Proyecto No. 80, and by Comisión de Investigación Cientiffica Universidad de Chile, Proyecto No. 95.     

Characterization of DNAs fromCoprinus lagopus andMucor azygospora

Resumé Les rapports G+C des ADN deCoprinus lagopus etMucor azygospora ont été étudiés. Le profil de fusion indique que l'ADN duC. lagopus est composé de deux fractions, une principale (90%) de rapport G+C 52 moles pourcent, une mineure (10%) de G+C 32 moles pourcent. Par contre l'ADN deM. azygospora contient une fraction unique de G+C 38 moles pourcent. L'étude de la cinétique de réassociation DNA:DNA montre que la dimension génomique («genome size») deC. lagopus est de 2×10¹² et qu'il y a moin de 10% de DNA à séquences répétées de nucléotides.

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This research was supported in part by the U.S. Atomic Energy Commission Contract No. AT (40-1) 4182 and the Research Corporation, New York, to S.K.D. We are grateful to ProfessorG. Turian, University of Geneva, for making possibleM. Ojha's participation in this research.     

Differential effect of silybin on the Fe2+-ADP and t-butyl hydroperoxide-induced microsomal lipid peroxidation

Summary We have observed a differential effect of silybin dihemisuccinate on rat liver microsonal oxygen consumption and on lipid peroxidation induced by NADPH-Fe²⁺-ADP and t-butyl hydroperoxide. These results are ascribed to the antioxidant properties of the flavonoid. The differences observed in the effect of the catalysts may be a consequence of the different capacity of silybin to act as a scavenger of free radicals formed by NADPH-Fe²⁺-ADP or t-butyl hydroperoxide.This research was supported in part by grant B-2019-8412 from Dirección de Investigación y Bibliotecas, Universidad de Chile.     

Effect of hypothalamic crude extract on the utilization of D-[14C]-glucose by the anterior pituitary,in vitro

Resumen Los efectos de extractos crudos de hipotalamo en la utilizacion deD-[¹⁴C]-glucosa por hipófisis anteriores fueram estudiados in vitro en condiciones identicas a aquelas en las cuales los extractos inducen la liberación de hormonas al medio de incubación. Los resultados indican que los extractos hipotalámicos aumentan la producción de¹⁴CO₂ por la hipófisis a partir de glucose y la incorporación de¹⁴C en proteinas del medio de incubación. Los extractos no modificaron la cantidad de¹⁴C glucose utilizada para sintesis de proteinas tissulares.     

Effect of trifluoperazine and calcium ions on gregarine gliding

Summary The drug trifluoperazine (TFP) inhibits the gliding motility of gregarine protozoans. This suggests that the Ca⁺⁺ binding protein, calmodulin, plays a role in the motility process. However the presence of extracellular Ca⁺⁺ was not required for gliding to occur.Acknowledgments. We should like to thank L. Cooper for technical assistance, Smith, Kline and French for the gift of trifluoperazine, and Terry Preston for valuable discussion.     

The exchange of bone calcium with Ca

Résumé L'emploi combiné de l'isotope radioactif du calcium et de la dissolution progressive des sels osseux par HCl a permis de démontrer que le calcium échangeable de la substance minérale osseuse correspond au calcium adsorbé et à celui qu'elle renferme en excès par rapport au phosphate tricalcique fondamental.

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This work was sponsored by theAir Research and Development Command, United States Air Force, through its European Office: contract n^o AF 61(514)-647 C, and the Centre Interuniversitaire des Sciences Nucléaires of Belgium.     

Influence of chlorpromazine on nuclear and cytoplasmic uptake of35S-methionine

Résumé Des rats ont été traités avec de la chlorpromazine et ont reçu en suite une seule injection de³⁵S-méthionine. Des radioautographies des coupes histologiques ont montré que la chlorpromazine a un effect inhibitoire dans la synthèse de la protéine nucléaire et cytoplasmatique. Les cellules qui ont une grande vitesse de synthèse protéique sont les plus affectées.

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This investigation was supported by grants from the Rockefeller Foundation and Conselho Nacional de Pesquisas.

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The authors wish to acknowledge the help of Prof. L. C. U.Junqueira for criticism and encouragement, and MissEdna Freymüller for her skilled technical assistance.     

Binding of 5-hydroxytryptamine and noradrenaline by rat lung

Résumé Après injection i.v. de 5-hydroxatryptamine-C¹⁴ et de noradrénaline-H³ à des rats, on a préparé et centrifugé des homogénates de leurs poumons dans un gradient linéaire de sucrose. Après sacrifice immédiat ces deux amines sont retrouvées dans une grande fraction de particules pulmonaires sédimentant dans 1M de sucrose. Après 30 min les poumons des rat offrent un pic additionel de noradrénaline-H³ correspondant à une densité de sucrose de 0.4 à 0.5.

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This work was supported in part by Grant No. 13315 from the U.S. Public Health Service and by Grant No. 435 from the Connecticut Heart Association. Assistance provided by Ayerst Laboratories and Astra Laboratories is also gratefully acknowledged.     

Effects of sphingolipids on erythroblastic maturation in the mouse

Summary The changes effected by injection of an extract of phospholipids obtained from the plasma of normal human donors (PLE) or an emulsion of commercially available sphingolipids on erythropoiesis in the mouse were studied. The parameters followed were⁵⁹Fe uptake by the erythroid tissue and the number of circulating reticulocytes. It was found that in the 12–24-h period following administration of PLE or purified sphingomyelin a significant increase in⁵⁹Fe uptake by circulating RBC and by their hemic fraction takes place. This change was associated with a higher⁵⁹Fe utilization by the bone marrow and with an increase in the number of circulating reticulocytes.Acknowledgments. This work was supported by a grant from the Consejo Nacional de Investigaciones científícas y Técnicas de la República Argentina. We thank Isabel Zingariello and Maria Amalia Nicastro for excellent technical assistance.     

Asymmetrical activation by Ca2+ of the erythrocyte membrane K+-dependent phosphatase

Resumen Los sitios con los cuales se combinan el ion Ca y el ATP para activar la fracción dependiente, ce K⁺ de la fosfatasa de la membrana del glóbulo rojo, están ubicados en la superficie interna de dicha membrana. Esta característica de asimetría, favorece la idea de la relación de esta enzima con la ATPase activada por Ca²⁺ de la membrana del glóbulo rojo.

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This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Argentina, and the Facultad de Farmacia y Bioquímica. A.F.R. and P.J.G. are established investigators from the CONICET.     

The incorporation of carbon labelled precursors into the nucleic acids of various tissues in the intact rabbit

Résumé Les résultats expérimentaux montrent le degré d'incorporation du formate-¹⁴C, de l'adénine-8-¹⁴C et de la glycine-2-¹⁴C dans l'ADN et dans les ARN nucléaire et cytoplasmique de l'appendice, de la mlle osseuse, de la muqueuse intestinale, du rein, du foie, de la rate et du thymus du lapinin vivo.     

An alternative decomplementation method for the measurement of the survival of human erythrocytes transfused into rats

Summary An alternative technique for measuring the survival of⁵¹Cr-labelled human erythrocytes transfused into rats is described, in which aggregated human gamma-globulin is substituted for cobra venom factor as a decomplementing agent.Acknowledgments. This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico.     

Oxidation of cholesterol by rat liver mitochondria: Influence of deuterium oxide

Résumé L'oxydation du cholestérol-26-¹⁴C et de l'octanoate de sodium-1-¹⁴C par une préparation de mitochondries de foie de rat a été effectuée en milieu aqueux à un pH de 8,5 et dans l'eau lourde (D₂O) à un pH de 8,1 et 8,5. La présence d'eau lourde a inhibé l'oxydation des deux substrats. L'oxydation du cholestérol dans l'eau lourde à un pH de 8,5 a été réduite de 60% à 70% de la valeur normale et de plus de 90 % dans l'eau lourde à un pH de 8,1. Aux deux valeurs de pH, l'oxydation de l'octanoate a été réduite de 50% à 70%.     

Incorporation of phospholipids in Ehrlich ascites tumor cells

Summary Ehrlich ascites tumor cells (EATC) were incubated with unilamellar vesicles (UV) or multilamellar vesicles (MV). UV and MV were incorporated differently into EATC. The increase in³²P-phospholipid in EATC in the presence of UV was 12% in 300 min. Absorption of phospholipid from MV could account for only 3%. About 50% of the UV incorporation of³²P was by endocytosis and/or fusion.This work was supported by a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. J. L. Corchs is an investigator from the Consejo Nacional de Investigaciones Científicas y Técnicas.