Biomedical subjects

E Rotreklová

Publications and source records attributed to E Rotreklová.

12 recordsLinked to original sources

PubMed1985

The rates of replicative and unscheduled DNA synthesis as functions of temperature in LS/B1, L-As and L-C3 cells.

The relative rates of replicative and unscheduled DNA synthesis were determined over a temperature range of 2 degrees to 42 degrees C in LS/B1, L-As and L-C3 cells. The rates were determined by measuring the amount of 3H-dTh incorporated into DNA during 60 min incubation of cells at a given temperature. Acid-resistant 3H-activity incorporated into DNA at 2 degrees C was evaluated as evidence of DNA turnover, not non-specific adsorption of 3H-dTh. The relative rates of RDS and UDS were expressed as functions of temperature and from the data the values of Q10 and Eact necessary for incorporation of one mole of dTh into DNA during RDS and UDS were calculated. The values of Q10 and Eact are comparable to those reported for HeLa, V-79, L5/78Y and the epithelial cells. The experimentally determined values of Q10 and Eact for UDS in the lines tested did not vary. UDS, compared to RDS, is evaluated as a process with lesser demands for energy.

Animals↗

PubMed1985

Changes in DNA capacity for actinomycin-D binding in nuclei of interphase cells.

3H-AMD binding to DNA in interphase nuclei was tested on asynchronous and synchronous LS/BL cell populations under physiological conditions and after exposure to gamma rays (60Co). 3H-AMD binding to DNA in an asynchronous cell population appeared to be nearly constant and independent of 3H-AMD concentration. However, in comparing individual cells, a great variability could be observed. In synchronized cells the DNA accessibility for 3H-AMD binding changed in the course of the cell cycle, with a maximum occurring at the late G1-phase (13.95 X 10(-12) mumol/nucleus) and a minimum at the late G2-phase (2.63 X 10(-12) mumol/nucleus). In irradiated cells the DNA capacity for 3H-AMD binding was growing with the increasing dose (5-80 Gy) from 4.9 to 11.2 X 10(-12) mumol 3H-AMD/nucleus.

Animals↗

PubMed1982

Inhibition of entry into S phase and DNA synthesis in bone marrow cells of mice by repeated injections of gentamycin.

The effect of gentamycin on bone marrow cells in unirradiated and irradiated mice was investigated by 3H-dTh incorporation into DNA using microautoradiography. Gentamycin was injected in vivo at 20 mg base/kg body weight at 8-h intervals during three days. In mice exposed to 4.78 Gy the injections of gentamycin were started on the 7th day after irradiation. In granulopoietic and erythropoietic cells the inhibition of entry of cells into S phase and the retardation of DNA replication was about 20%. The roughly 30% inhibition of entry of cells into S phase observed when the bone marrow cell population has been evaluated as a whole is discussed in terms of increased sensitivity of the young blast-like cells.

Animals↗

PubMed1980

Inhibition of bone marrow cell proliferation and DNA replication induced by chloramphenicol.

The effect of CAP on proliferations of bone marow cells from unirradiated and irradiated (4.78 Gy) C57BL/10 mice was investigated by 3H-dTh incorporation into DNA of individual cells using autoradiography. CAP was administered from day 7 to day 10 after irradiation. CAP decreases the rate of entry of cells into S phase and the rate of 3H-dTh incorporation into DNA during replication. Cells of the erythropoietic series are mainly involved in this decrease. CAP has roughly the same inhibitory effect on unirradiated and irradiated cell populations.

Animals↗

PubMed1977

Grain distribution in autoradiograms of nuclei of synchronized HeLa cells continuously labelled with 3H-thymidine.

Changes in distribution of silver grains were evaluated in autoradiograms of nuclei of synchronized HeLa cells that were continuously labelled with 3H-TdR. Synchronization was achieved by repeated blocking with cold thymidine. Three patterns of grain distribution were distinguished: uniform, non-uniform, and a special case of non-uniform distribution, the S.C. clustering. The kinetics of changes in the proportion of individual types of grain distribution indicate that uniform and non-uniform distribution patterns result from 3H-TdR incorporation into DNA replicating during the entire S-phase, whereas DNA responsible for clustered grain distribution takes up 3H-TdR only during the second half of the S-phase. The rate of the increase in grain counts per nucleus of labelled cell and the kinetics of the exhaustion of radioactive precursor from the culture medium suggest that replication of DNA in DNA in the S-phase is not merely a linear function of time.

Autoradiography↗

PubMed1972