The inhibitory effect of D-glucosamine on thymidine kinase in chick embryo retinas and HeLa cells

D-Glucosamine markedly inhibits thymidine incorporation into the TCA-insoluble fraction and thymidine kinase activity in HeLa cells. Both the inhibitory effects are also observed in isolated retinas of chick embryos. In this case the inhibitory effects are age-dependent and the magnitude of the responses decreases with embryonic development. In addition the time of exposure to D-glucosamine which is necessary to reveal the inhibitory effect on thymidine kinase increases with the age of the embryos.     

Differentiation of chick embryo brain cells in culture

Résumé Des cellules, encore à un stade indifférencié, dissociées d'hémisphères cérébraux d'embryon de Poulet ont formé, en culture, des fibres nerveuses. La plupart des cellules se différencient en neuroblastes unipolaire et bipolaire; certaines évoluent vers le type multipolaire sans contact direct avec des cellules gliales.

---

---

Chargée de Recherche au CNRS.     

Estrogen-induced phosvitin synthesis in cultured chick embryo liver cells

Riassunto È stata dimostrata la capacità di culture primarie di fegato embrionale di sintetizzare fosvitina in vitro dopo trattamento con estrogeni.     

Influence of progesterone on protein and RNA synthesis in cultured chick embryo liver cells

Summary Chick embryo liver primary cultures, when added with progesterone, exhibit, in comparison with the controls, a normal growth, a decline of both³H-uridine uptake and incorporation into total RNA, a decline of³H-leucine and¹⁴C serine incorporation into the proteins. Progesterone is not able to stimulate phosvitin synthesis induction.These studies were supported in part by the Italian CNR grants.     

Growth of chick aortic endothelial cells: Incorporation of tritiated uridine and thymidine

Zusammenfassung Zellen der Kückenaorta zeigten, dass der Einbau von H³-behandeltem Uridin oder Thymidin in linearem Verhältnis zur Zeitdauer der Stoffeinwirkung stand. Sekundäre, ebenso alle weiteren Zellkulturen ergaben markante Zunahme der linearen Pyrimidinaufnahme, eine Inkorporation, die mit zunehmender Zellgrösse und höherem Stoffwechsel zusammenhängt.

---

---

Supported by NIH grants HE-05998, and Research Career Award AI-K6-20-517 to Dr.J. J. Quilligan jr.; Atomic Energy Commission contract AT(04-3)-322; and grants from the John A. Hartford Foundation and the Crenshaw Research Foundation.

---

On leave from University of Tokyo School of Medicine, Tokyo (Japan).     

Effects of phenethyl alcohol on influenza virus growth and macromolecular synthesis in chick embryo cells

Zusammenfassung Phenethylalkohol wirkt virusstatisch und es wird vermutet, dass die mit der Zellmembran in Beziehung stehenden Vorgänge der Zellvermehrung beeinflusst werden.     

Influence of progesterone on protein and RNA synthesis in cultured chick embryo liver cells.

Chick embryo liver primary cultures, when added with progesterone, exhibit, in comparison with the controls, a normal growth, a decline of both 3H-uridine uptake and incorporation into total RNA, a decline of 3H-leucine and 14C serine incorporation into the proteins. Progesterone is not able to stimulate phosvitin synthesis induction.     

Ventral neural tube cells differentiate into hepatocytes in the chick embryo

A population of ventral neural tube cells has recently been shown to migrate out of the hind brain neural tube via the vagus nerve and contribute to the developing gastrointestinal tract. Since liver is also innervated by the vagus nerve, we sought to determine if these cells also migrate into the liver. Ventral neural tube cells in the caudal hindbrain of chick embryos were tagged with a replication-deficient retroviral vector containing the LacZ gene on embryonic day 2. Embryos were processed for detection of labeled cells on embryonic day 5 and 11. Labeled cells were seen in the liver on both days and identified as hepatocytes. Previously, it was believed that all hepatocytes develop from the gut endoderm. Results of the present study show an additional source for the formation of liver cells. Received 25 August 1998; received after revision 5 November 1998; accepted 5 November 1998