Density gradient centrifugation of cells separated from multicellular tumor spheroids.

Cells from a murine fibrosarcome (FSa) have been grown in vitro as multicell tumor spheroids (MTS). The growth rate of these MTS was determined. Following selected periods of growth, MTS were made into a single cell suspension and separated on linear density gradients of Renografin. While only 1 population of cells were separated from small spheriods (400 mum diameter), at least 3 subpopulations of tumor cells were separated and isolated from large spheroids (800 mum in diameter).     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

Summary A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.This investigation was supported by grant CA-18628, awarded by the National Cancer Institute, Department of Health and Human Services.     

Production of Friend virus particles at the surface of cells synchronized by Ficoll gradient centrifugation]

Murine cells continuously producing Friend viral complex were synchronized by Ficoll gradient centrifugation. Cells were isolated from different parts of the gradient and counts of budding particles were performed on ultra-thin sections. No significant differences were noticed, suggesting that viral release is not related to cell cycle.     

Limitations in the quantitative separation of DNA samples by density gradient centrifugation

Résumé Des mélanges de l'ADN («léger») et de l'ADN-¹⁴ C-BU («lourd») ont étés centrifugés dans le chloride de caesium pendant 65 h à 60,000g. Le résidu de l'ADN «lourd» dans l'ADN «léger» fut de l'ordre de 0.1 à 1%. La grandeur du résidu n'a pas correspondu à la proportion de l'ADN «lourd», ni à la concentration totale de l'ADN dans le chloride de caesium.     

Heterogeneity of HeLa cell DNA as evidenced by CsCl density gradient centrifugation

Summary HeLa cell DNA was analyzed through CsCl density gradient centrifugation and thermal denaturation. Neutral centrifugation without ionic treatment allowed the resolution of a main peak with density 1.699 g/ml and of 3 satellites DNAs with densities 1.683, 1.710 and 1.720. First derivatives of melting curves showed the presence of 4 DNA families, whose G+C content calculated from T_m values corresponded almost exactly to the G+C content expected from the previously densities. The extraction method seems particularly suitable for quantitative separation of DNA classes.     

Isolation of plasmid DNA fromAgrobacterium by isopycnic density gradient centrifugation in vertical rotors

Summary Fixed angle and vertical rotors are compared in terms of their sample load, run time, and resolution for the preparation of plasmid DNA fromAgrobacterium.Acknowledgments. This work was supported by a CASE Studentship from the SRC and ICI Corporate Laboratories to J.D., and a grant from the SRC to M.R.D. and E.C.C. The authors thank Mr B.V. Case for photographic assistance.     

Isolation of a pharmacologically active principle from ehrlich carcinoma tumor cells

Résumé Les propriétés biologiques d'une nouvelle substance pharmacologique active isolée des cellules de l'ascite d'Ehrlich sont décrites en détail. La substance isolée contracte in vitro l'iléum du cobaye ou l'utérus du rat et relaxe l'ileum de la souris. In vivo, cette substance possède un effet hypotensif chez le chat.     

Degranulating activity in hybrid cells derived from rat peritoneal mast cells and ehrlich ascites tumor cells

Summary Fusion of rat mast cells and Ehrlich ascites tumor cells was mediated by HVJ. Compound 48/80-induced degranulation occurred in the fused cells formed from two mast cells and one tumor cell, but not in the fused cells from one mast cell and two or more tumor cells.I am grateful to DrK. Utsumi for valuable discussions and for the donation of HVJ.     

Purification of porcine granulosa cells by continuous Percoll gradient

Granulosa cells purified on a continuous Percoll gradient have considerably increased responsiveness to FSH in formation of cAMP, secretion of progesterone, and 125I[hCG] binding to cells incubated for 4 days in culture.     

Physical properties of deoxyribonucleic acid isolated from Ehrlich ascites tumor cells by various methods

Zusammenfassung Die Desoxyribonukleinsäure des Ehrlich-Karzinoms wurde nach vier verschiedenen Methoden isoliert und Stickstoff- und Phosphorgehalt sowie die physikalischen Eigenschaften für jedes der vier Präparate bestimmt. Die mit Hilfe von Natrium-Xylolsulfonat isolierte Desoxyribonukleinsäure scheint am stärksten polymerisiert zu sein.     

Preferential cytotoxicity on tumor cells by caffeic acid phenethyl ester isolated from propolis

The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat/human versus transformed rat/human melanoma and breast carcinoma cell lines in the presence of CAPE.     

Preferential cytotoxicity on tumor cells by caffeic acid phenethyl ester isolated from propolis

Summary The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat/human versus transformed rat/human melanoma and breast carcinoma cell lines in the presence of CAPE.