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Biomedical subjects

V Spurná

Publications and source records attributed to V Spurná.

35 records · Page 2Linked to original sources
PubMed1975

Hypoxanthine guanine phosphoribosyltransferase (HGPRT) activity in hybrids derived from HGPRT+ and HGPRT- mouse cells.

By utilizing the selection system, a population of hybrid cells with the gene coding HGPRT and sensitive to 8-azaguanine (8-AG) was isolated from a mixed population of hybrid cells derived from malignant diploid HGPRT+ mouse lymphosarcoma cells (LS/BL) and L cells resistant to 8-AG (HGPRT-, R-AG/20 strain). During back-selection of this hybrid population , cultivated in vitro, HGPRT- negative fractions of the cell population, resistant to 8-AG, appeared in a high frequency. As a rule, the telocentric chromosomes (or chromosome), originated from the HGPRT+ parental cells (LS/BL), were lost in these cells. The X chromosome of the LS/BL cells coding the HGPRT enzyme was not present in all cells of the hybrid HGPRT+ population. Hence it is assumed that the fusion of HGPRT+ (LS/BL) and HGPRT- (R-AG/20) cells resulted in a reexpression of the HGPRT activity from the R-AG/20 parental cells.

Animals↗
PubMed1975

Incorporation of exogenous DNA and its localization in the chromosomes of the host cell.

Incorporation of isologous 3H-DNA of exogenous origin into chromosomes of the L cells was investigated by means of autoradiographical technique. It was shown that during short time intervals of incubation of 3H-DNA with the host cells (1--3 hr), nearly double quantity of the mitoses was labelled, when compared with 3H-TdR used as a control. During longer time intervals, no difference between number of the mitoses labelled with 3H-TdR and exogenous isologous 3H-DNA was observed.

Animals↗
PubMed1975

Light and electron microscopy of mouse lymphosarcoma LS/BL cells during the first hour after irradiation with x-rays.

Mouse lymphosarcoma LS/BL cells growing in tissue culture were irradiated with 100, 316 and 1000 R respectively and fixed 5, 15 or 60 minutes later. Semithin sections were studied under a light and ultrathin under an electron microscopes. Under the light microscope, differences between the morphology of individual nuclei were found in all groups, including controls; the rate of their occurrence was without any relation to the irradiation. They may reflect the differences in the state of LS/BL cells which were not completely adapted to cultivation in small glass tubes. On the other hand, the frequency of some ultrastructural changes seen under the electron microscope showed a relation to the irradiation. They were: undulation of the outer nuclear membrane and dilatation of the space between the outer and inner nuclear membranes, slots in karyosomes adjacent to the surface of the nuclei, enlargement of cisternae and vesicles of endoplasmic reticulum and Golgi apparatus. The importance of a careful examination of control groups in such experiments is stressed.

Animals↗