Specific gravity of cell types in differentiating central nervous system of chick

Zusammenfassung Es wird gezeigt, dass das Gewicht der Nervenzellen ihrem Herkunftsort aus dem Neuralrohr entspricht, das heisst, Vorderhirnzellen sind schwerer als Rückenmarkzellen.     

Occurrence of polyploidy and multinuclearity in the differentiating liver of chick embryo

Summary Increase in nuclear size in liver has been used as an index of polyploidy. It has long been considered that the occurrence of polyploidy and multinuclearity are characteristics of mammalian liver. The present study shows the occurrence of these phenomena in the liver of birds, so these features are not confined to mammals. 3 classes of nuclear size groups have been identified. The simultaneous occurrence of polyploidy and binuclearity indicates some sort of interrelationship between them.     

Estimation of free glutamic acid in the differentiating central nervous system of the chick

Zusammenfassung Es wird der Gehalt an Glutaminsäure in den embryonalen Entwicklungsstadien des Hühnergehirns festgestellt.     

Neurosecretory cell types in normal taste bud

Riassunto Nella presente nota vengono esaminate da un punto di vista ultrastrutturale particolari cellule presenti nel calice gustativo normale, per alcuni aspetti assai simili alle cellule del I tipo e contenenti numerose vescicole di tipo neurosecretorio.     

Localization of acid phosphatases in the cell fractions of chick liver

Summary 3 molecular forms (P1, P2 and P3) of acid phosphatase (E.C.3.1.3.2) have been detected in chicken liver homogenate. The different intracellular localization of these molecules has been demonstrated by cellular fractionation and electrophoretic analysis. P1 and P2 phosphatases are both present in the particulate fraction. P3 is present in a pure form in the soluble fraction. The difference between the enzyme molecules present in the particulate fraction and that in the soluble one is confirmed by the different activation-inhibition effect of various ions and substances on the enzymatic activity of subcellular fractions.     

In vitro culture of chick down feather bulbi: a tool to obtain proliferating and differentiating keratinocytes in an organotypic structure

Chick down feather bulbi can be cultured in different culture systems. Morphological analysis and 3H-thymidine incorporation measurements prove that the majority of cells are viable epithelial cells.     

In vitro culture of chick down feather bulbi: A tool to obtain proliferating and differentiating keratinocytes in an organotypic structure

Summary Chick down feather bulbi can be cultured in different culture systems. Morphological analysis and³H-thymidine incorporation measurements prove that the majority of cells are viable epithelial cells.     

Adrenalectomy effect on pituitary cell types

Résumé Dans l'hypophyse du rat normal, les cellules a occupent 39%. Après l'adrenalectomie bilatérale, les cellules b deviennent le type cellulaire prédominant (47%) au profit des cellules a, tandis queles cellules c restent peu changées. L'ACTH minimise ce changement des types cellulaires. Cela indique que l'adrenalectomie a causé un état hyperfonctionnel des cellules de type b.     

Innervation of the ovarian interstitial cell of the chick embryo

Summary Electron microscopic examination of the developing ovary of 15–20-day chick embryos revealed that the interstitial cells were well innervated. Nerve fibres and nerve endings were observed in close contact with steroid-producing cells.     

Alteration of cell shape in the early chick embryo mesoderm by neuraminidase

Summary Living chick embryo mesoderm cells (stages 3 to 5) were exposed to neuraminidase. The mesoderm cells changed shape losing their long thin processes and become like primitive streak cells, with short flat processes. Ruthenium red staining of such treated embryos shows that the surface coat on the mesoderm cells is reduced in thickness. These results show that cell shape in the chick embryo mesoderm is at least partly determined by the thickness and the composition of the surface coat.Acknowledgment. It is a pleasure to thank Professor F. Beck for the facilities of the Department of Anatomy, University of Leicester, and Mr. G. L. C. McTurk of the University of Leicester Scanning Electron Microscope Unit for operating the ISI 60 SEM. Mr Jeff Smith and Mrs Doris Duncan gave us valuable technical assistance and Dr. A. J. Rowe kindly allowed us to use the facilities of the Electron Microscope Unit, University of Leicester School of Biological Sciences, in specimen preparation.     

Lactic dehydrogenase isoenzymes in various cell types of mouse liver

Zusammenfassung Mit einer einfachen Methode wird demonstriert, dass Lebergewebe von Mäusen in 2 Fraktionen verschiedener Menge an Bindegewebe zu trennen ist. Die an Bindegewebe reiche Fraktion zeigt Enzymaktivität in LDH 1, 2, 3, 4 und 5. Nach Entfernung des Bindegewebes wird die Aktivität der LDH 1, 2, 3 und 4 Isoenzyme des restierenden Lebergewebes reduziert.