Killing of Cultured Mammalian Cells by Radioactive Decay of Tritiated Thymidine at -196°C

1970 ◽  
Vol 41 (2) ◽  
pp. 409 ◽  
Author(s):  
H. John Burki ◽  
S. Okada
Keyword(s):  
Mammalian Cells ◽  
Tritiated Thymidine ◽  
Radioactive Decay

Studies of the 'Adaptive' Repair Response in Human Lymphocytes and V79 Cells after Treatment with MNNG and MNU

1988 ◽  
Vol 7 (4) ◽  
pp. 337-341 ◽  
Author(s):  
D. Anderson ◽  
P. Fisher ◽  
P.C. Jenkinson ◽  
B.J. Phillips
Keyword(s):  
Adaptive Response ◽  
Mammalian Cells ◽  
Tritiated Thymidine ◽  
Human Lymphocytes ◽  
Alternative Methods ◽  
X Rays ◽  
V79 Cells ◽  
Repair Mechanisms ◽  
Experimental Protocols ◽  
Mutagenic Effects

In bacteria, there is evidence that a damage inducible repair response system known as the adaptive response exists since pretreatment with low doses of a simple monofunctional alkylating agent leads to a decrease in both the lethal and mutagenic effects of a subsequent challenge dose of the agent. The evidence for an analagous system in mammalian cells has proved to be inconsistent to date. The induction of chromosome repair mechanisms in human cells by low-dose radiation from tritiated thymidine has been shown to make the cells refractory to the induction of chromosome aberrations by X-rays. The present communication investigates the induction of an adaptive response in human lymphocytes from four donors and V79 cells using SCE and mutation as endpoints and MNNG and MNU for the adapting and challenging treatment. It is clear that a reproducible model of the adaptive response in human lymphocytes is difficult to establish because of the variability between different donors and different culture times. In V79 cells, assays with much larger cell numbers are required to detect a reproducible response with such small changes in mutant frequency. To demonstrate an adaptive response conclusively in mammalian cells will probably require the use of more sensitive experimental protocols and alternative methods of administration of adaptive doses of mutagen.

Synchronization of Mammalian Cells with Tritiated Thymidine

Science ◽  
1966 ◽  
Vol 151 (3711) ◽  
pp. 691-694 ◽  
Author(s):  
G. F. Whitmore ◽  
S. Gulyas
Keyword(s):  
Mammalian Cells ◽  
Tritiated Thymidine

Action of Tritiated Thymidine on the Clonal Growth of Mammalian Cells

1959 ◽  
Vol 11 (4) ◽  
pp. 535 ◽  
Author(s):  
Ruth M. Drew ◽  
Robert B. Painter
Keyword(s):  
Clonal Growth ◽  
Mammalian Cells ◽  
Tritiated Thymidine

Visualization of Surface-Associated Nucleic Acid in Tumoricenic Cells Using Ultrathin Frozen Sections and Platinum-Pyrimidine Complexes

1976 ◽  
Vol 34 ◽  
pp. 204-205
Author(s):  
Surinder K. Aggarwal
Keyword(s):  
Mammalian Cells ◽  
Tritiated Thymidine ◽  
Membrane Surface ◽  
Sarcoma 180 ◽  
Frozen Sections ◽  
Tumor Biopsy ◽  
Normal Cells ◽  
Ultrathin Frozen Sections ◽  
Tumor Implant ◽  
Plasma Membrane Surface

Platinum-pyrimidine complexes have been used as sole electron-dense stains for electron microscopy on number of mammalian cells (1-3) . They are selective for areas rich in nucleic acids and stain the cellular chromatin, ribosomes and nucleolus. Tumorigenic cells exhibit special binding on the plasma membrane surface in the form of dense patches; normal cells do not. Solid tumor biopsy samples from animals and humans show similar patches but only in malignant tissues. Various enzymatic studies suggest that the electron-dense patches are DNA with neuraminic acid involved in the binding. Autoradiographic studies using H3 -thymidine confirms the presence of surface- associated DNA.Swiss Webster mice bearing ascites sarcoma-180 tumor are given intraperitoneal injection of 7. 0 μ c of tritiated thymidine in 0. 5 ml sterile 0. 85% NaCI on day 5 of the tumor implant.

scholarly journals DISTRIBUTION OF LABELED CHROMATIN

1970 ◽  
Vol 47 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Jean H. Priest ◽  
Robert H. Shikes
Keyword(s):  
Mammalian Cells ◽  
Tritiated Thymidine ◽  
Daughter Cells ◽  
Chromatid Segregation ◽  
Count Distribution ◽  
Random Segregation ◽  
Single Grain ◽  
Discrete Populations ◽  
Rule Out ◽  
Diploid Human Fibroblast

The question of whether distribution of chromatids to daughter cells in mitosis is a random or nonrandom process was investigated by study of the distribution of labeled chromatin in anaphase pairs at M1 and M2 after a pulse of tritiated thymidine. Diploid and tetraploid rat and diploid human fibroblast-like cells in serial monlayer culture were synchronized by two different methods to "purify" M1 and M2 anaphases: metaphase shake, and FUdR block to DNA synthesis followed by exogenous thymidine. Exposed grains of NTB-2 emulsion were counted over M1 and M2 anaphase pairs. An analysis (by pair) of diploid M2 anaphase grain counts showed two discrete populations of daughters with less and with more radioactivity. A similar analysis of diploid M1 and tetrapolid M2 anaphases showed a single grain-count distribution. These findings may support a nonrandom model of chromatid segregation for diploid mammalian cells but do not rule out random segregation until sound mathematical models are formulated for expected random grain distributions in M2 anaphases of cells with differing numbers of chromosomes.

scholarly journals EVIDENCE FOR AN ESSENTIALLY CONSTANT DURATION OF DNA SYNTHESIS IN RENEWING EPITHELIA OF THE ADULT MOUSE

1963 ◽  
Vol 18 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Ivan L. Cameron ◽  
Richard C. Greulich
Keyword(s):  
Dna Synthesis ◽  
Mammalian Cells ◽  
Adult Mouse ◽  
Tritiated Thymidine ◽  
Constant Duration ◽  
The Times ◽  
Time Required ◽  
Relationship Of

Tritiated thymidine autoradiography has been applied to several renewing epithelial tissues of the adult mouse in order to determine (a) the average time required for DNA synthesis; and (b) the temporal relationship of the synthesis period to the progenitor cycles of these populations. The average duration of DNA synthesis has been computed from curves describing the rates of appearance and disappearance of labeled metaphase figures in epithelia of colon, ileum, duodenum, esophagus, and oral cavity, in both normal and colchicine-treated animals. In general, application of colchicine does not significantly influence the derived values for DNA synthesis duration. The DNA synthetic time is remarkably similar in the tissues examined, despite wide differences in the times required for completion of the progenitor cycle (and for tissue renewal). Synthesis of DNA in these epithelial cells of the mouse requires approximately 7 hours. Agreement between this value and those derived by other investigators for mammalian cells in vivo and in vitro indicates that DNA synthetic time may be a temporal constant, of considerable potential utility to studies of cell proliferation. The advantages and shortcomings of this experimental approach to problems of cell population kinetics in vivo are discussed.

Ultrastructural Alterations in Hela Cells Induced by Spider Venom

1967 ◽  
Vol 25 ◽  
pp. 20-21
Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff
Keyword(s):  
Growth Medium ◽  
Mammalian Cells ◽  
Carcinoma Cells ◽  
Venom Protein ◽  
Sterile Saline ◽  
Carbon Coated ◽  
Available Information ◽  
Loxosceles Reclusa ◽  
Essential Growth ◽  
Solution Cultures

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.

Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

1967 ◽  
Vol 25 ◽  
pp. 136-137
Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Specific Antiserum ◽  
Electron Microscopic ◽  
E Coli ◽  
Cytoplasmic Membranes ◽  
Viral Progeny ◽  
Ultrathin Sections ◽  
Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

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