Instances of sex inversion in the domesticated swordtail, Xiphophorus helleri Heckel (Pisces, Osteichthyes)

3 protogynous hermaphrodites were found in a domesticated strain of Xiphophorus helleri, confirming much doubted observations by older authors. It therefore seems that sex determination may vary between strains, certain strains being strictly gonochoristic but others being capable of true hermaphroditism.     

Instances of sex inversion in the domesticated swordtail,Xiphophorus helleri heckel (pisces,osteichthyes)

Summary 3 protogynous hermaphrodites were found in a domesticated strain ofXiphophorus helleri, confirming much doubted observations by older authors. It therefore seems that sex determination may vary between strains, certain strains being strictly gonochoristic but others being capable of true hermaphroditism.     

Urinary catecholamine metabolites (vanylmandelic and homovanillic acds) in the rat after subchronic treatment with sodium nitrate or nitrite

Summary Sodium nitrate and nitrite in rat food (5 and 0.5% respectively) result in a decrease of both food intake and growth. These agents induce a specific increase in the urinary excretion of 2 catecholamine metabolites: vanylmandelic and homovanillic acids.This work was supported by D. G. R. S. T. grant No. 80. G. 0908 (Nutrition humaine — Toxicologie alimentaire).     

Structural basis for resetting of baroreceptor regulation in spontaneously hypertensive rats (SHR)

Zusammenfassung Nachweis, dass in Ratten mit genetischem Hochdruck und normalem Herzrhythmus Verdickungen des Endotheliums im Karotissinus und im Aortabogen beobachtet werden. Eine Hypertrophie der Gefässmuskulatur war nachweisbar, was zu einer Abschwächung des Drucksignals zur Stelle der Pressorezeptoren führte. Diese dürften teilweise verantwortlich sein für die Verschiebung der Pressorezeptor-Steuerung bei genetisch hypertensiven Ratten.

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This study is partly supported by I.W.O.N.L.     

Fibrinolytic system in the dog with experimental renal (goldblatt) hypertension

Résumé Nous avons constaté, au cours de l'hypertension arterielle produite chez le chien d'après la technique deGoldblatt, l'inhibition de la fibrinolyse des euglobulines, l'augmentation considérable de fibrinogène et de plasminogène. L'intervention chirurgicale de contrôle produisit seulement une augmentation moindre de fibrinogène, sans inhibition de la fibrinolyse.

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Supported in part by a grant from the Polish Academy of Sciences, Department II and VI.     

Expression of multidrug resistance (mdr) gene(s) in primary lymphoid organs of chicken immune system during embryonic development

The presence of a multidrug resistance (MDR) related protein, P-170, in normal and pathological lymphoid cells has been described. The present report evaluates the expression of themdr 1 gene by using the reverse Polymerase Chain Reaction (PCR) on cells obtained from the thymus and bursa of chicken embryos starting from day 12 until hatching. Results show that the thymic cells are positive from day 12 to the end of the observation period. In contrast,mdr mRNA was detected in the bursa from day 14 to day 17 of embryonic life. Possible relationships between the expression ofmdr and the development of T and B lymphocytes are discussed.     

Peroxidase and gamma-glutamyl transpeptidase activities during Eimeria nieschulzi (Apicomplexa) and/or Nippostrongylus brasiliensis (Nematoda) infections in the rat

Results suggest that malabsorption of amino acids which occurs during Eimeria nieschulzi and Nippostrongylus brasiliensis infections in rats is not due to impairment by intestinal inflammation of gamma-glutamyl transpeptidase activity.     

Haemolymph ecdysteroids level following the injection of ecdysone or ecdysterone; its relation with tegument and midgut response inAeshna cyanea (Insecta,Odonata)

Summary The haemolymph ecdysteroid level after injection of ecdysone or ecdysterone inAeshna cyanea larvae has been determined by a radioimmunoassay method. The rate of excretion appears to be dependent on both the ecdysteroid injected and the time of injection. In case of ecdysone injection, the secretion of the epidermis cuticle and the differentiation of the imaginal midgut epithelium occur when the ecdysteroid level remains low for many days.