Biosynthesis of ascorbic acid in chick embryos

Summary Biosynthesis of ascorbic acid was found in the kidneys (mesonephros and metanephros) of the chick embryo as well as in the yolk sac membrane. The activity of L-gulonolactone oxidase in the yolk sac membrane suggested that it was the major source of ascorbic acid in the chick embryo.I am grateful to Dr R. Jenness (Univ. of Minnesota) for the generous gift of L-gulonolactone and to Dr B. Sanders (Univ. of Texas) for the chick embryo samples     

Biosynthesis of ascorbic acid in chick embryos

Biosynthesis of ascorbic acid was found in the kidneys (mesonephros and metanephros) of the chick embryo as well as in the yolk sac membrane. The activity of L-gulonolactone oxidase in the yolk sac membrane suggested that it was the major source of ascorbic acid in the chick embryo.     

Plasma transcortin concentration in thyroidectomized chick embryos

Summary Concentrations of transcortin binding sites and apparent dissociation constants for corticosterone have been measured in the blood of control and thyroidectomized chick embryos. The levels of corticosterone binding are quantitatively similar in normal and thyroidectomized embryos and vary in parallel during development.     

Mitotic activity during successive migrations in the diencephalon of chick embryos

Zusammenfassung Mitosezählungen bestätigen das vonBergquist undKällén ¹¹ angenommene Verhältnis zwischen Proliferation und sukzessiver Migration. Der Rhythmus der Mitoseaktivität, denKällén ¹⁵ im rhombenzephalen Teil des Neuralrohres während der ungleichen neuromerischen Phasen nachgewiesen hat, entspricht also einer ähnlichen Aktivität bei der sukzessiven Migration in der Area thalami.Im Unterschied zur Mitoseaktivität in den genannten Proliferationsstadien tritt die sukzessive Migration nur lokal auf (Bergquist ¹⁴).Erst einige Zeit, nachdem die Mitoseaktivität ihr Maximum erreicht hat, erscheint die Migrationsschicht. Dies ist wahrscheinlich dadurch bedingt, dass bei der Proliferation die Zellen im Neuralepithel an der Ventrikeloberfläche entstehen, in der Ventrikelwand in lateraler Richtung wandern und sich zum Schluss in einer zusammenhängenden Migrationsschicht sammeln, die vom weiter innen liegenden Neuralepithel deutlich abgegrenzt ist.     

Development of the steady potential differences of the eyeball in chick embryos

Résumé Le potentiel D. C. mesuré sur la surface du globe oculaire de l'embryon de poulet croît à partir du 15 ème jour de 0.92±0.21 mV jusqu' à 9.26±0.76 mV au 21 ème jour l'incubation. L'augmentation maximum se situe entre le 17 ème et 18ème jour (2.57 et 6.61 mV). Elle correspond à la mise en jeu de l'appareil visuel afférent. La stabilité du potentiel D. C. du globe oculaire est directement proportionnelle à sa valeut.     

Neuromuscular blocking activity of dibekacin,a new semisynthetic aminoglycoside antibiotic

Summary Dibekacin possesses the untoward effect of producing a neuromuscular blockade. Neostigmine is unable to reverse the neuromuscular blockade produced by dibekacin. Calcium has not only the ability to restore the neuromuscular transmission but also to exert protective action against the neuromuscular blocking activity of dibekacin.     

Identification of catecholamines and serotonin in the notochords of chick embryos]

The neurotransmitter amines, norepinephrine, dopamine and serotonine have been isolated from Chick notochords. Cholinergic agents produce important modifications in the amount of these amines and of one of their metabolites. The results demonstrate the presence, at a very early stage of development, between the second and the third day of incubation, of biogenic amines and cholinergic receptors.     

On the presence of glycogen in the rhombencephalon of chick embryos during development

Riassunto Viene condotto uno studio sulla distribuzione del glicogeno nel romboencefalo dell'embrione di pollo durante lo sviluppo. I risultati delle indagini condotte hanno messo in evidenza una caratteristica localizzazione del glicogeno nell'abbozzo del ponte e del bulbo più evidente in embrioni dal 7° al 13° giorno di incubazione. Tale reperto viene discusso nel suo significato.     

Plasma testosterone concentration in control and testosterone-treated chick embryos

Summary After testosterone propionate treatment (1 or 2 mg per embryo), plasma testosterone in chick embryos rises to 500 times higher than in control animals, and then progressively diminishes during the following days of incubation. These drastic changes in hormonal status after the IP treatment entails consequences that may be considered pharmacological rather than physiological.Acknowledgment. We would like to thank Mrs N. Jeanguyot (UNCEIA, Laboratoire d'hormonologie, Maisons Alfort, France) for her excellent technical assistance in the RIA procedure.     

Janus green B and experimental syndactyly in chick embryos

Zusammenfassung JanusgrÜn B mit oxidativen Fermenten, insbesondere mit dem FAD, geht eine Komplexverbindung ein, die eine Syndaktylie zur Folge hat. Die Abbauprodukte des JanusgrÜn B (Diäthylsafranin undp-Dimethylanilin) wirken zwar gleich toxisch wie das JanusgrÜn B, haben aber keinen Syndaktylie-Effekt.

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We are indebted to Prof. B.Menkes for his advice and generous aid in our problems.