Purin- und Pyrimidinbasen der Desoxyribonukleinsäure des Ehrlichschen Mäuse-Ascites-Karzinomas

Summary The proportion of purines and pyrimidines in the DNA of the Ehrlich mouse ascites carcinoma is examined and compared with the base proportion of the DNA from liver and kidney of the normal mouse. The following findings were obtained: The DNA of the ascites tumor contains more guanine and less cytosine and thymine than the DNA of the normal mouse. For guanine this difference is statistically significant. The changed base compound is discussed with regard to the changed growing rate in tumors and the altered chromosome structure in the Ehrlich ascites carcinoma.

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Durchgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Permeability of Ehrlich ascites cells and spectrophotometric assay of the sub-cellular enzymes

Summary A permeabilization method which allows the assay of intracellular enzymes of the Ehrlich ascites cells is described. The developmental changes in the activity of lactic dehydrogenase and glucose-6-phosphate dehydrogenase of toluene-treated Ehrlich ascites cells were studied.Acknowledgment. M.D. is grateful to CSIR for the award of Junior fellowship.     

Cyclosporins: immunosuppressive agents with antitumor activity

Initial screening of the 2 recently developed immunosuppressive agents, cyclosporin A and cyclosporin C, in 11 murine transplantable neoplasms revealed significant increase of lifespan with long-term survivors after i.p. injection to the ascites tumors, Taper liver, Sarcoma 180J and Ehrlich.     

Änderung der Wachstumskinetik von Ehrlich-Aszitestumoren verschiedener Ploidie nach Röntgen-Bestrahlung

Summary The effect of irradiation (500 R) on the cell cycle of the diploid (EAT_dipl.) and the hypertetraploid (ELT) Ehrlich ascites tumor growing in the peritoneal cavity of male NMRI mice has been studied autoradio-graphically by the double labelling technique (H³- and C¹⁴-thymidine) and the method of labelled mitoses. The results suggest that the proliferation kinetics of tumor cells after irradiation depends on the type of tumor cell strain tested. Identical results were obtained after application of the alkylating agent cyclophosphamide (100 mg/kg).     

Antitumor activity of the Isodon diterpenoids: structural requirements for the activity.

A significant antitumor activity of oridonin (1) and lasiokaurin (2), the kaurene-type diterpenoids of Isodon species, was shown by their i.p. injection to the test mice inoculated by Ehrlich ascites carcinoma. Enmein (8), compounds 9 and 3 were also active under larger dose. Subsequently, the relationship between their chemical structure and antitumor activity was investigated, and the activity of oridonin (1) and lasiokaurin (2) was rationalized in terms of their structural feature.     

Rosette formation of tumor cells with concanavalin A treated erythrocytes

Summary Trypsinized human erythrocytes were incubated with concanavalin A at 4°C. After removal of free concanavalin A, the erythrocytes were incubated with Ehrlich ascites tumor cells at 37°C. The erythrocytes formed rosettes with the tumor cells.     

Cyclosporins: Immunosuppressive agents with antitumor activity

Summary Initial screening of the 2 recently developed immunosuppressive agents, cyclosporin A and cyclosporin C, in 11 murine transplantable neoplasms revealed significant increase of lifespan with long-term survivors after i.p. injection to the ascites tumors, Taper liver, Sarcoma 180J and Ehrlich.This work was supported in part by grant CA-08748 from the National Cancer Institute, National Institutes of HealthDepartment of Health, Education and Welfare. The authors are indebted to Drs Dorris J. Hutchison, M.N. Teller and H. Stähelin for helpful discussions, and to Dr A. von Wartburg of Sandoz AG, Basel, for the supply of the cyclosporins.     

2,4-dinitro-(pyrimidine-2-yl) thiophenol, a new drug with antimitotic properties]

A new thiopyrimidine derivative has been synthesized. It can inhibit cell multiplication in Chick embryo fibroblasts, in Mouse Ehrlich ascites tumor cells and in Rat hepatoma cells (line Rueber) cultivated in vitro.     

Antitumor activity of the isodon diterpenoids: Structural requirements for the activity

Summary A significant antitumor activity of oridonin (1) and lasiokaurin (2), the kaurene-type diterpenoids ofIsodon species, was shown by their i.p. injection to the test mice inoculated by Ehrlich ascites carcinoma. Enmein (8), compounds9 and3 were also active under larger dose. Subsequently, the relationship between their chemical structure and antitumor activity was investigated, and the activity of oridonin (1) and lasiokaurin (2) was rationalized in terms of their structural feature.     

5-Methylangelicin: a new highly photosensitizing angular furocoumarin

5-Methylangelicin, a new highly photosensitizing angular furocoumarin, was studied in 2 different biological systems, the T2 phage and Ehrlich ascites tumor cells; in comparison with angelicin, the parent compound, it was several times more active.     

Incorporation of phospholipids in Ehrlich ascites tumor cells

Ehrlich ascites tumor cells (EATC) were incubated with unilamellar vesicles (UV) or multilamellar vesicles (MV). UV and MV were incorporated differently into EATC. The increase in 32P-phospholipid in EATC in the presence of UV was 12% in 300 min. Absorption of phospholipid from MV could account for only 3%. About 50% of the UV incorporation of 32P was by endocytosis and/or fusion.     

Inhibition of Ehrlich ascites carcinoma (EAC) growth by carbonyl iron

Summary Treatment of Ehrlich ascites carcinoma (EAC) cells with carbonyl iron (20 mg/ml) produces a significant decrease in growth rate of tumor inoculum both in Swiss and in C57BL/6 mice. Possible interaction of the carbonyl iron or Fe⁺⁺⁺ions with cell surface is suggested.Supported by a grant from the Consiglio Nazionale delle Ricerche.Acknowledgments. The authors are grateful to Dr M. M. Clynes (University College, Dublin, Ireland) for his helpful discussion.     

Formation of proviruses in acute infection in vitro and in vivo

Summary Formation of DNA proviruses of RNA viruses, Sendai and Newcastle disease, was studied. DNA provirus of NDV was shown to be formed in mouse L-cells and Sendai DNA provirus in Ehrlich ascites carcinoma cells within 2–3 days post infection.     

Vergleichende Untersuchungen an Proteinen von Influenzaviren

Summary Evidence is mainly indirect that certain animal RNA viruses integrate host material into their envelope. For example, influenza adapted to Ehrlich ascites tumor is immunogenic against the tumor cells in mice. However, even in polyacrylamide, it was impossible to find significant differences in protein composition of influenza WSA grown in different hosts, whereas differences between strains could easily be detected. The conclusion is that host protein integration is improbable.

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Arbeit mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung (Kredit Nr. 5254.3). Frl.U. Kohler danke ich für Mitarbeit und Herstellung der Skizzen.     

Über den zeitlichen Ablauf der Aktivierung von Cyclophosphamid im Menschen und die Testung der zytostatisch aktiven Form an Ehrlich-Mäuse-Aszites-Tumorzellen

Summary The cytostatic action of human blood serum, following intravenous injection of cyclophosphamid, on cell proliferation and lactic production of Ehrlich mouse ascites tumour cells in vitro was tested. The maximum cytostatic activity was found 2 h after injection.     

Effect of heat-labile enterotoxin (LT) produced byEscherichia coli on in vitro cell proliferation

Summary Filtrates fromE. coli H10407 cultures, giving a positive response for heat-labile enterotoxin (LT) in the Y-1 cell test, show an inhibitory activity both on³H-thymidine uptake by Ehrlich ascites cells and on granulocytic-macrophagic precursors (CFU-C) in murine bone marrow.Acknowledgments. We gratefully acknowledge the expert technical assistance of L. Basso and A. Gerosa of Department of Pathology, Hospital of Desio.     

5-Methylangelicin: A new highly photosensitizing angular furocoumarin

Summary 5-Methylangelicin, a new highly photosensitizing angular furocoumarin, was studied in 2 different biological systems, the T₂ phage and Ehrlich ascites tumor cells; in comparison with angelicin, the parent compound, it was several times more active.Acknowledgments. The authors wish to thank Mrs M. Peron for her excellent technical assistance.     

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.     

Relationship between A-type and C-type particles in Ehrlich ascites tumor cells.

Intracisternal and intracytoplasmic A-type particles were discovered in Ehrlich ascites tumor cells. In addition, 'mature' and 'immature' C-type particles were also seen in the intercellular space. It is believed that A particles may represent a precursor or a formative stage of the C particles.     

Presence of natural killer cells in Peyer's patches of the mouse

Summary Natural cell-mediated cytotoxicity of normal murine Peyer's patch cells against Ehrlich ascites carcinoma was found in a short-term⁵¹Cr release assay. Peyer's patch and lymph node cells showed natural cytotoxicity at approximately the same level.Acknowledgments. This work was supported by grant No. 10.5 from the Polish Academy of Sciences.