Using a combined cytophotometric-autoradiographic method a study was made of 3H-thymidine and 3H-deoxycytidine incorporation rates into the interphase nuclei of rabbit kidney cell culture during the S-period. The rate of 3H-deoxycytidine (10(-4) M--10(-6) M) incorporation into nuclei increases throughout the first part of the S-period and decreases from its middle to the end. The patterns of variations of 3H-thymidine and 3H-deoxycytidine incorporation rates into the nuclei of cultured rabbit kidney cells during the S-period were identical.
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J Biol Chem
June 1997
Department of Biology, University of Padova, Via Trieste 75, 35121 Padova, Italy.
We incorporated 3H-labeled thymidine, deoxycytidine, or cytidine into dNTPs and DNA of exponentially growing CEM cells. G1 and S phase cells were separated by centrifugal elutriation, and the size and specific activity of dNTP pools were determined to study the cell cycle-dependent regulation of specific dNTP synthesizing enzymes in their metabolic context. With [3H]thymidine, we confirm the earlier demonstrated S phase specificity of thymidine kinase.
View Article and Find Full Text PDFAPMIS
December 1992
Department of Ophthalmology, University of Oslo, Rikshospitalet, Norway.
In the rat corneal epithelium the mitotic rate (MR) is almost equal throughout the epithelium in the morning (Haaskjold et al. 1988). The labelling index (LI) shows a marked reduction in the central cornea, which could suggest a lack of uptake of tritiated thymidine via the salvage pathway (Haaskjold et al.
View Article and Find Full Text PDFBiochim Biophys Acta
August 1992
Department of Microbiology and Immunology, University of Adelaide, Australia.
A broad-specificity nucleoside transporter has been identified in Giardia intestinalis trophozoites, using a rapid sampling assay to measure influx of [3H]deoxycytidine, [3H]adenosine and [3H]guanosine at 0 degrees C. The influx of each labelled nucleoside was inhibited strongly by all common, naturally-occurring nucleosides but only poorly or not at all by nucleobases, indicating that the transporter recognizes structural features on the furanosyl moiety of ribo- and 2'-deoxyribonucleosides. Both 2'- and 5'-deoxyadenosine were potent inhibitors of influx (greater than 95% inhibition at 2 mM), whereas 3'-deoxyadenosine was significantly less effective (approx.
View Article and Find Full Text PDFAm J Physiol
October 1991
Department of Medicine, New England Medical Center, Boston, Massachusetts 02111.
The pulmonary endothelium is known to be sensitive to oxidant injury, including that of hyperoxia. Similar to effects of exposure to 80-95% O2, porcine platelet transforming growth factor (TGF)-beta 1 at concentrations of greater than or equal to 0.3 ng/ml inhibited proliferation and caused enlargement of bovine pulmonary artery endothelial cells after 24 h of incubation in room air.
View Article and Find Full Text PDFBiochem Pharmacol
May 1990
Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510.
The effect of 3'-deoxythymidin-2'-ene (d4T) on the metabolism of exogenously supplied radiolabeled nucleosides was investigated. Following a 24-hr exposure to 250 microM d4T, we observed no significant effect on the incorporation of [3H]thymidine or [3H]deoxycytidine into DNA. In contrast, the amounts of [3H]uridine, [3H]deoxyuridine, and [3H]cytidine were significantly lower than those incorporated by control cultures.
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