The pharmacological action of gastrin pentapeptide

Zusammenfassung Bei Stimulation der Magensekretion bei nichtnarkotisierten Hunden mit Heidenhain-Taschen durch Histamin und synthetisches Gastrin-Pentapeptid konnte die Wirkung des letzteren durch Ganglienhemmer vergrössert und durch Atropin vermindert werden. Die Wirkung des Histamins wurde durch Ganglienhemmer herabgesetzt. Die Versuche zeigen, dass Histamin und Gastrin-Pentapeptid verschiedene Wirkungsmechanismen besitzen.     

Dual antiglioma action of metformin: cell cycle arrest and mitochondria-dependent apoptosis

The present study reports for the first time a dual antiglioma effect of the well-known antidiabetic drug metformin. In low-density cultures of the C6 rat glioma cell line, metformin blocked the cell cycle progression in G₀/G₁ phase without inducing significant cell death. In confluent C6 cultures, on the other hand, metformin caused massive induction of caspase-dependent apoptosis associated with c-Jun N-terminal kinase (JNK) activation, mitochondrial depolarization and oxidative stress. Metformin-triggered apoptosis was completely prevented by agents that block mitochondrial permeability transition (cyclosporin A) and oxygen radical production (N-acetylcisteine), while the inhibitors of JNK activation (SP600125) or glycolysis (sodium fluoride, iodoacetate) provided partial protection. The antiglioma effect of metformin was reduced by compound C, an inhibitor of AMP-activated protein kinase (AMPK), and was mimicked by the AMPK agonist AICAR. Similar effects were observed in the human glioma cell line U251, while rat primary astrocytes were completely resistant to the antiproliferative and proapoptotic action of metformin. Received 14 February 2007; received after revision 26 March 2007; accepted 3 April 2007     

Comparison of DMSO and glycerol as cryoprotectants for ascites tumor cells

Summary Mouse Ehrlich ascites and rat D23 ascites tumors were stored in liquid nitrogen under identical conditions for up to 3 years. Cell viability (trypan blue exclusion) and transplantability of both tumors in animals remained virtually unaffected if preserved in 10% DMSO containing medium, whereas, cells preserved in 10% glycerol failed to produce lethal tumors in rodents.This work was performed at the Cancer Research Unit, Royal Victoria Infirmary, Newcastle Upon Tyne, England. I thank John Geggie for expert technical assistance; to the North of England Council of the Cancer Research Campaign and the National Science Foundation (ENG-78-25432) for financial support; and to Dr John A. Dickson for advice and encouragement. Also, I am indebted to Professor Rakesh K. Jain for his support.     

FITC-dextrans as fluorescence and electron microscopic tracers in studies on capillary and cell permeability of the CNS

FITC-dextrans can be detected at the ultrastructural level as round electron dense particles, with no sign of distortion or aggregation. Because this tracer is a stable, non-toxic polymer of biological origin obtainable in a wide range of molecular weights, it may be useful for further studies of tissue permeability.     

FITC-dextrans as fluorescence and electron microscopic tracers in studies on capillary and cell permeability of the CNS

Summary FITC-dextrans can be detected at the ultrastructural level as round electron dense particles, with no sign of distortion or aggregation. Because this tracer is a stable, non-toxic polymer of biological origin obtainable in a wide range of molecular weights, it may be useful for further studies of tissue permeability.The author is grateful to Ms. H. Büscher and Ms. S. Klemt, Department of Pathology, for their excellent technical assistance.     

An effect of DMSO on post-irradiation saccharin avoidance in mice

Zusammenfassung Ein Dimethylsulfoxyd (DMSO)-Effekt wird beschrieben: bei Nachbestrahlung vermeiden Mäuse Sodium-Saccharin. Mit DMSO vorbehandelte Tiere (Eintauchen der Schwänze in diese Substanz kurz vor Bestrahlung) bevorzugen wie unbehandelte Mäuse Saccharin-Sodium.

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This work was supported in part by Grant No. PHS-SOI-FR-5369-04-5 from the University of Illinois, Graduate College of Medicine.     

Anin vitro action of deoxycorticosterone (DOC) on red cell electrolytes

Résumé Dans les suspensions d'érythrocytes humains incubées avec du glucose et du déoxycorticostérone glucoside, K diminue, tandis que Na, H₂O et P augmentent. Ces globules rouges, traîtés avec des hormones, absorbent notablement moins d'oxygène de bleu de méthyle que les érythrocytes de contrôle.     

Glycerol permeability of erythrocytes

Zusammenfassung Untersuchungen über die Unterschiede in der Lipoidzusammensetzung der Erythrocyten von neun Tierarten ergaben eine verschiedene Glyzerinpermeabilität dieser Zellen. Bei der einen Gruppe zeigen die Erythrocyten eine stark temperatur bedingte Glyzerinpermeabilität, bei der anderen eine hohe, kaum temperaturabhängige Permeabilität, die bei Erniedrigung des pH-Wertes im Medium stark abnimmt.