Selective incorporation of zinc into rat mast cells

Zusammenfassung Bei der Albinoratte findet sich 48 h nach parenteraler Verabreichung von radioaktivem Zink (Zn⁶⁵) ein hoher Anteil der Aktivität in den Gewebemastzellen. Nach Verabreichung des chemischen Histaminliberators, Compound 48/80, wird ein erheblicher Teil von Zn⁶⁵ aus den Zellen frei.

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This work was supported by the Schweizerische Nationalfonds zur Förderung der wissenschaftlichen Forschung (Grant No. 5200.3).     

In vitro protein synthesis and alpha amylase activity in F cells from hepatopancreas of Palaemon serratus (Crustacea; Decapoda).

In crustaceans, all the steps in the assimilation of food take place in the hepatopancreas. To facilitate the study of this organ, a method for the dissociation of cell types was developed. The hepatopancreas of the prawn Palaemon serratus was mechanically dissociated and the cells separated by Percoll density-gradient centrifugation. The E and R cells had similar densities of around 1.05 g/ml. The F cells were separated into two distinct fractions with densities of 1.075 and 1.082 g/ml. The B cells sedimented at a density of 1.12 g/ml. The ratio between the two populations of F cells was found to vary during the intermolt cycle while B cells disappeared after the molt. When the density gradient fractions were incubated with 3H-leucine, incorporation was highest in the F cell fractions. Measurements of alpha-amylase activity, indicated that the two populations of F cells may be derived from the same cell type.     

Dimethyl sulphoxide effect on division cells

Resumen Dimetil sulfóxido, potente antimetabolito, a distintas concentraciones altera significativamente la cinética de poblaciones meristemáticas radicales deAllium cepa L., produciendo un cuatro de alteraciones morfológicas y figuras mitóticas atípicas.     

Interaction of thymic cells and hemopoietic stem cells. Enhancing effect on irradiated thymus repopulation]

In irradiated mice engrafted with hemopoietic cells, the thymus is repopulated more rapidly by bone marrow-derived than by spleen-derived cells. Admixing thymic cells with the restorative suspension stimulates the thymic repopulation by spleen-derived cells whereas it has no effect on the repopulation by bone marrow-derived cells.     

The effect ofLophozozymus pictor toxin on hela cells

Zusammenfassung Ein wässeriger Extrakt einer besonderen Krabbenart (Lophozozymus pictor) erweist sich als toxisch gegenüber HeLa-Zellen. Es kommt zu Umwandlungen der Zellform sowie des Cytoplasmas. Die Reaktion scheint leicht erfassbar und ist für einen Toxizitätstest besser geeignet als der bis jetzt verwendete Mäusetest.

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We thank Prof.J. E. Gardiner for supporting the project and the Department of Bacteriology, University of Singapore, for the supply of HeLa cells.     

The effect of epinephrine and the hyperglycemic factor of the scorpion's cephalothoracic ganglionic mass (CTGM) on the phosphorylase activity of hepatopancreas of the scorpion,Heterometrus fulvipes C. Koch

Summary Injection of epinephrine and CTGM extract showed different effects on hepatopancreatic phosphorylase activity and levels of total carbohydrate and glycogen in heterometrus fulvipes. The former hyperglycemic principle involves phosphorolysis of glycogen whereas the latter does not.The authors are grateful to Proff. K. S. Swami and S. Nagaiah. An award of Junior Research Fellowship by the Council of Scientific and Industrial Research, New Delhi is acknowledged by K. R.     

Direct toxic effect of isoproterenol on cultured cardiac muscle cells

Summary Isoproterenol at relatively high doses (2.5 mg/ml) has a marked toxic effect on rat heart muscle cells cultivated in vitro. This effect is not prevented by propranolol and therefore is not mediated by beta adrenergic receptors.This work has been supported in part by a grant from the Muscular Dystrophy Association, Inc. to Prof. M. Aloisi.     

The effect of pyrophosphate and diphosphonates on calcium transport in red cells.

The effect of 0.5 mM pyrophosphate (PPi), disodium ethane-4-hydroxy-1,1-diphosphonate (EHDP) and disodium dichloromethane diphosphonate (Cl2MDP) on the ATP-dependent Ca2+ extrusion from the human red cell ghosts was studied. PPi and Cl2MDP had no effect, when introduced into the cells or added outside to the medium. EHDP slightly increased the calcium concentration in the released cells and slightly decreased the rate constant of the calcium transport, having opposite effects when it was inside or outside the cells. PPi and the 2 diphosphonates were not found to move easily across the red cell membrane.     

The effect of bisphosphonates on glycolysis in cultured calvaria cells and their homogenate

Rat calvaria cells previously cultured for 7 days in the presence of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) or dichloromethylenebisphosphonate (Cl2MBP), showed a decrease in the glycolytic pathway. When glycolysis was analyzed under anaerobic conditions, this effect was not observed. The inhibition by the bisphosphonates occurred to a similar degree regardless of whether lactate production was measured in whole cells or in cell homogenates. Bisphosphonates added directly to the homogenate had no inhibitory effect. Thus, the effect is not a direct one and is unlikely to be due to a soluble mediator in the cytoplasm.     

Heterochromatin characterization and distribution in the chromosomes of two populations ofIdotea baltica basteri Audouin, 1826 (Isopoda,Valvifera)

Two mediterranean populations ofIdotea baltica basteri from Messina and Naples showed a set of chromosomes composed by 58 all-biarmed chromosomes. The heterochromatin was located in the pericentromeric region of the chromosomes, and its composition appeared heterogeneous. In fact, not all the homologs showed heterochromatin resistant to digestion with three restriction enzymes (Alu I, Hae III and Sau 3A). Moreover, the two populations showed polymorphism in a band of G+C-rich telomeric heterochromatin, which was present only in the population from Messina. It is hypothesized that chromosomal polymorphism might reflect the geographical isolation of the two populations. It is also suggested that a process of diversification is taking place.     

Protective effect of interferon on the target cells of cytotoxic lymphocytes

Interferon treatment of sensitized T lymphocytes enhances cytotoxicity against target cells. On the contrary, the same treatment of the target cells alone protects them, whatever the cytotoxicity of effector cells might be. We suggest that the cells having once survived contact with cytotoxic T lymphocytes could become resistant to any new attack by the same cells.     

The effect of catecholamines and nicotine on the transmembranal potential of frog liver cells

Resumen La adrenalina (0.1 a 0.5 mg/rana) hiperpolarizó los hepatocitos deR. pipiens y depolarizó a dosis mas altas. El inhibidor de la monoamino oxidasa pargilina (100 mg/kg, 24–48 h antes) impidió este efecto.