Epidermal mitotic rate and DNA synthesis after injection of water extracts made from mouse skin treated with actinomycin D: Two or more growth-regulating substances?

1971 ◽  
Vol 7 (1) ◽  
Author(s):  
K. Elgjo ◽  
H. Hennings ◽  
W. Edgehill
Keyword(s):  
Dna Synthesis ◽  
Actinomycin D ◽  
Mouse Skin ◽  
Mitotic Rate ◽  
Water Extracts

scholarly journals Identification of a BALB/c-3T3 cell protein modulated by platelet-derived growth factor.

1983 ◽  
Vol 3 (1) ◽  
pp. 70-81 ◽  
Author(s):  
C D Scher ◽  
R L Dick ◽  
A P Whipple ◽  
K L Locatell
Keyword(s):  
Growth Factor ◽  
Dna Synthesis ◽  
Cell Lines ◽  
Actinomycin D ◽  
Platelet Derived Growth Factor ◽  
Cell Protein ◽  
Transformed Cells ◽  
Antigenic Determinants ◽  
3T3 Cells ◽  
Constitutive Synthesis

The platelet-derived growth factor (PDGF) stimulates density-arrested BALB/c-3T3 cells to synthesize a protein (pII; Mr, 35,000) that is constitutively synthesized by spontaneously transformed BALB/c-3T3 (ST2-3T3) cells which do not require PDGF for growth. Antisera against a major excreted protein family (MEP) of retrovirus-transformed cells quantitatively precipitated cellular pII. PDGF-stimulated pII has the same molecular weight, a similar charge, and similar antigenic determinants as authentic MEP isolated from ST2-3T3 or retrovirus-transformed cells. MEP represented about 2% of the nonnuclear proteins synthesized by ST2-3T3 cells and 0.3 to 0.6% of the proteins synthesized by PDGF-treated BALB/c-3T3 cells, a three- to sixfold increase over the background. In BALB/c-3T3 cells, less PDGF was required for pII (MEP) synthesis than for DNA synthesis. PDGF induced a selective increase in pII (MEP) within 40 min. Such preferential synthesis was inhibited by brief treatment with actinomycin D, suggesting a requirement for newly formed RNA. The constitutive synthesis of pII (MEP) by ST2-3T3 cells was not inhibited by actinomycin D. Five spontaneously or chemical carcinogen-transformed tumorigenic BALB/c-3T3 cell lines were studied; they neither required PDGF for growth nor responded to it. These cell lines became arrested at confluence with a G1 DNA content. Each of these independently isolated lines synthesized pII (MEP) constitutively. Thus, the synthesis of pII (MEP) may be required, but is not sufficient, for PDGF-modulated DNA synthesis.

Effects of Acute and Subchronic Exposure of Topically Applied Fullerene Extracts on the Mouse Skin

1993 ◽  
Vol 9 (4) ◽  
pp. 623-630 ◽  
Author(s):  
Mark A. Nelson ◽  
Frederick E. Domann ◽  
G. Tim Bowden ◽  
Stephen B. Hooser ◽  
Quintus Fernando ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Ornithine Decarboxylase ◽  
Mouse Skin ◽  
Tumor Formation ◽  
Skin Tumor ◽  
Toxic Effects ◽  
Exposure Level ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Acute Toxic

The recent discovery that fullerenes (C60) can be produced in macroscopic quantities has sparked much interest in the chemistry of this unusual molecule. Concerns have also arose about the potential carcinogenic effects of this molecule. We have addressed the potential acute and subchronic toxic effects of fullerenes applied in benzene on the mouse skin. The acute toxic effects measured in this study included epidermal DNA synthesis and the induction of ornithine decarboxylase activity in the epidermis. At the topical dose of fullerenes used in these studies (i.e., 200 ug), we found no effect on either DNA synthesis or ornithine decarboxylase activity over a 72 hour time course after treatment. The subchronic effects of the fullerenes as a mouse skin tumor promoter was assessed by repeatedly applying the chemical to the skin after initiation with the polycyclic aromatic hydrocarbon, 7,12-dimethlybenz-anthracene (DMBA). Repeated administration of the fullerenes for up to 24 weeks post-initiation did not result in either benign or malignant skin tumor formation, whereas promotion with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in the formation of benign skin tumors. Our data indicate that fullerenes applied in benzene at a likely industrial exposure level do not cause acute toxic effects on the mouse skin epidermis.

scholarly journals NUCLEAR MEMBRANES OF CULTURED MAMMALIAN CELLS IN THE PERIOD PRECEDING DNA SYNTHESIS

1965 ◽  
Vol 25 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Susumu Kishimoto ◽  
Irving Lieberman
Keyword(s):  
Ionizing Radiation ◽  
Dna Synthesis ◽  
Electrophoretic Mobility ◽  
Mammalian Cells ◽  
Elevated Level ◽  
Actinomycin D ◽  
Kidney Cells ◽  
Nuclear Membranes ◽  
L Cells

When kidney cells are cultured directly from the rabbit, the nuclear membranes undergo a change that can be measured as an increase in electrophoretic mobility. The change appears to begin immediately upon culture and is maximal 2 hours later, after which the mobility remains constant at the elevated level. Actinomycin D and p-fluorophenylalanine, but not EDTA or ionizing radiation, suppress the increase in nuclear electrophoretic mobility. With synchronously growing L cells, no change was detected in nuclei from cells taken during various parts of the division cycle.

scholarly journals Is there "Metabolic" DNA in the Mouse Seminal Vesicle?

1960 ◽  
Vol 7 (4) ◽  
pp. 657-666 ◽  
Author(s):  
Joseph G. Gall ◽  
William W. Johnson
Keyword(s):  
Dna Synthesis ◽  
Seminal Vesicle ◽  
Intraperitoneal Injection ◽  
Mitotic Rate ◽  
Thymidine Uptake ◽  
Metabolic Function ◽  
Unimodal Distribution ◽  
Chromosome Duplication ◽  
Silver Grains

This study was designed to answer the question: Is H3-thymidine uptake by nuclei of the mouse seminal vesicle evidence for DNA synthesis and mitosis, or does it signify some "metabolic" function of DNA unrelated to chromosome duplication? Mice were given an intraperitoneal injection of H3-thymidine. Six hours later Feulgen squashes of the seminal vesicle epithelium were made and covered with autoradiographic stripping film. The silver grains above labeled nuclei were counted, and the Feulgen dye contents of these same nuclei were determined photometrically after removal of the grains from the emulsion. Unlabeled nuclei were also measured. The dye contents of non-radioactive nuclei form a unimodal distribution, indicating that polyploidy is absent from this tissue. The radioactive nuclei fall into two groups. In the first, the average dye content is the same as that of the cold nuclei (2C). In the second, the values range from 2C to 4C. In the 2C to 4C group the grain count is proportional to the dye content, showing that incorporation is correlated with synthesis. The radioactive 2C nuclei arose by mitosis during the course of the experiment. This is shown by the following facts: (1) They frequently occur in pairs. (2) They average smaller than unlabeled 2C nuclei. (3) Their average grain count is approximately half that of the 4C nuclei. (4) Labeled division figures are found. (5) A mitotic rate estimated from the number of labeled 2C nuclei accords reasonably well with one based on the number of observed mitoses. Since the incorporation of thymidine accompanies DNA synthesis and precedes mitosis, there is no reason to postulate a special "metabolic" DNA in this tissue.

DNA synthesis in the developing rat brain

1969 ◽  
Vol 47 (1) ◽  
pp. 47-50 ◽  
Author(s):  
Shan-Ching Sung
Keyword(s):  
Dna Synthesis ◽  
Rat Brain ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Rapid Rate ◽  
In Vitro Synthesis ◽  
Infant Rat ◽  
Developing Rat

The in vitro synthesis of DNA as measured by the incorporation of thymidine-2-14C into DNA has been studied for various regions of the infant rat brain. Both intact cerebellum and cell-free extracts of cerebellum from newborn and infant rat brain showed a very rapid rate of DNA synthesis which was highest around 6 days after birth and decreased rapidly thereafter up to 18 days. This DNA synthesis in developing rat brain was strongly inhibited by hydroxyurea but was much less sensitive than was RNA synthesis to inhibition by actinomycin D.

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