Showing papers in "Experimental Cell Research in 1969"

TL;DR: A bifunctional highly fluorescent quinacrine mustard was shown to give chromosome breaks preferentially localized to heterochromatic chromosome regions (identifiable by cold treatment) in the M-chromosome.

TL;DR: Great and reproducible differences in the uptake of the fluorescent reagents by different chromosome regions were observed and a good correlation was found between regions reacting with several different fluorescent compounds and heterochromatin as defined by cold treatment.

TL;DR: Silicon deprivation of young cells of C. fusiformis in light-dark synchronized cultures completely inhibited mitosis without affecting normal increase in volume and reintroduction of silicic acid to 12 h silicon-starved cells resulted in immediate stimulation of net DNA synthesis.

TL;DR: The cortisone-resistant cells, which are known to be located in the thymus medulla, were found to have the same volume distribution as normal lymph node lymphocytes.

TL;DR: l-Methyladenine brings about spawning as well as oocyte maturation in vitro in starfish, Marthasterias glacialis, Astropecten aurantiacus and Ceramaster placenta and appears to act only on the full-grown oocytes.

TL;DR: A rapid and simple method is described for the preparation of isolated crypt cells from the rat intestine that consists of intact crypts in high yield, free of other cellular structures, which can subsequently be disassociated to individual crypt cells by gentle agitation.

TL;DR: The results obtained show that the activation of a large number of genes in both human lymphocytes and hen erythrocyte nuclei is paralleled by striking changes in the melting profiles of nuclear DNP.

TL;DR: It is concluded that cyclic AMP plays a central role in the control of cell division in thymocyte populations and could be the intracellular mediator of the mitogenic actions of a wide variety of hormones on this type of cell.

TL;DR: It is demonstrated that EGF can act as a potent growth factor for the regulation of mammary epithelial cell proliferation, and it is suggested that it may function as a hormone.

TL;DR: Possible functions for these filamentous structures in producing and maintaining cell processes and in intra- and extracellular motility are proposed and the relationship of these structures to the birefringence seen in living cells is discussed.

TL;DR: The technique utilizes a newly designed planing apparatus and makes possible biochemical and physical analyses of cells in different stages of differentiation and provides a system for studying changes in macromolecular synthesis and the regulatory control of cell differentiation in the normal intestine.

TL;DR: The results reported clearly demonstrate a diurnal rhythm in the number of cells in mitosis and synthesizing DNA and no such rhythm was found in DNA synthesis rate.

TL;DR: The results indicate that adult human glia cells have unusually well developed growth control mechanisms in vitro and should lend themselves well to the experimental study of such controls.

TL;DR: The findings are compatible with autophagosome-lysosome fusion as the mechanism whereby lysosomal enzymes are brought in contact with sequestered cytoplasmic organelles for subsequent digestion.

TL;DR: The efficiency of the proposed technique for fractionation of the villous cells according to extent of migration is examined, and some surveys of chemical and enzymic changes during cell development are conducted.

TL;DR: It is suggested that the DNP-changes reflect the existence of a “chromatin activation reaction” which is essential for transforming inactive and highly condensed DNP and chromatin into active templates for RNA synthesis.

TL;DR: Observations support the contention that the double membrane-bound early cytosegresomes represent autophagosomes, and the notion that the wrapping membranes represent specialized areas of endoplasmic reticulum.

TL;DR: From the results presented, it is clear that the thymidine incorporation system of Chinese hamster cells suffers a high rate of spontaneous mutation.

TL;DR: The mechanical properties of the protoplasm of the fertilized sea urchin egg were determined by the magnetic particle method using a visco-elastic model consisting of a Voigt element and a viscous element connected in series.

TL;DR: It is proposed that interruption of DNA replication, and consequent chromosome aberration, are the result of the inhibition of protein synthesis, and Cycling of cultured cells through amino acid deprivation is proposed as a technique for deliberately increasing the rate of chromosome alteration in genetic experiments.

TL;DR: It was concluded that the difference in the activity between the two PHA fractions might be due to different contents of the stimulating factor, and acetylation of amino groups in the protein moiety of the DNP complex resulted in a marked increase in AO binding sites in nonstimulated cells while no such increase was found in PHA stimulated cells having a large number of accessible groups for AO bound proteins.

TL;DR: The intracellular migration of polymerase from the cytoplasm to the nucleus is suggested as a mechanism to account for early development results in sea urchin embryos.

TL;DR: Fibroblasts transformed by oncogenic viruses were found to have greater enzymic activities of 7 glycosidases on a cell or protein basis than two non-transformed cell lines.

TL;DR: The effects of ecdysone and juvenile hormone alone on the RNA synthesis could be inhibited by incubating the nuclei with both hormones together, and this effect seemed to be independent of the sodium stimulation.

TL;DR: A high percentage of single beating cells was obtained within one day in monolayer cultures of trypsin-dispersed embryonic mouse heart cells and synchronous beating occurred even when two independently beating myocardial cells were connected through intermediate FL cells, strain cells derived from human amnion.

TL;DR: Evidence is presented suggesting that calcium was compartmentalized or “packed” during the process of its transcellular transport, and it is postulated that a very specialized and selective form of pinocytosis, or endocytotic, underlies the active trans- cellular transport of calcium by epithelial tissues.

TL;DR: Heating the cultures above 40 °C caused a decrease in tension within the cell sheets, which may indicate that contraction of an extended fibroblast depends upon more than a single mechanism.

TL;DR: It is suggested that chloramphenicol has at least three effects in the cells of higher organisms—a specific inhibitory effect on the synthesis of some mitochondrial cytochromes which is presumably a reflection of its action on the mitochondrial protein synthesizing system, an effect on cellular ultrastructure, and a direct inhibitory effects on cellular respiration only at relatively high concentrations of the drug.