Availability of Tritiated Thymidine after Intravenous Administration

Staroscik, Rudolf N.; Jenkins, W. H.; Mendelsohn, Mortimer L.

doi:10.1038/202456a0

Cited by 50 publications

(13 citation statements)

References 3 publications

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“…Thymidine is rapidly incorporated into the DNA of synthesizing cells. Labelling, after injection of isotope, is complete within 30-60 min in both man (Rubini et al 1960) and experimental animals , Staroscik et al 1964. After this time the majority of the label is either fixed within DNA or degraded to soluble produets which are excreted, eontributing to a short period of availability of labelled nucleoside in vivo following single pulse labelling (Rubini et al 1960, Lundin 1963, Post et al 1963, Hughes et al 1964, clearance of label being more rapid after intravenous than intraperitoneal or intramuscular administration , Skougaard 1964, Animals are customarily killed or biopsies taken 1 h after injection of labelled thymidine on the assumption that nuclear labelling will have been completed within that period.…”

Section: Isotope Labelling Methodsmentioning

confidence: 99%

Epithelial cell kinetics – A review of methods of study and their application to oral mucosa in health and disease

Scragg

Johnson

1980

J Oral Pathology Medicine

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Despite extensive investigation of cell kinetic parameters in a wide range of normal and abnormal tissues and their potential value in understanding the pathogenesis of many disease states, as well as in prognosis and treatment planning, their application to oral epithelia remains limited. In part A the methods most commonly applied to the study of epithelial cell kinetics, i.e., isotope labelling, mitotic arrest and flow cytophotorimetry are reviewed with special emphasis on their technical limitations, sources of variation and inapplicability to humans in vivo. The ability of in vitro methods to reliably reproduce in vivo cell kinetic parameters is also considered. The application of cell kinetic studies to normal and abnormal oral tissues will be discussed in part B.

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Section: Isotope Labelling Methodsmentioning

confidence: 99%

Epithelial cell kinetics – A review of methods of study and their application to oral mucosa in health and disease

Scragg

Johnson

1980

J Oral Pathology Medicine

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“…When labeled Tdr is given intravenously, the tracer is rapidly cleared from plasma by cellular uptake. After mixing with the intracellular pool of Tdr, the labeled compound either undergoes phosphorylation before incorporation into DNA or follows a degradation pathway giving rise to labeled metabolites (28)(29)(30). Incorporation of Tdr is usually measured on the nuclei or on the DNA fraction to avoid counting contamination by labeled degradative products.…”

Section: Discussionmentioning

confidence: 99%

Uptake of Thymidine Labeled on Carbon 2: A Potential Index of Liver Regeneration by Positron Emission Tomography

Borght

Lambotte²,

Pauwels³

et al. 1990

Hepatology

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Noninvasive measurement of liver regeneration with positron emission tomography has been attempted with 11C-thymidine; however, results were unsatisfactory using thymidine labeled on its methyl group. To evaluate whether the specificity of the method could be improved by modifying the labeling position of the tracer, thymidine labeled on its methyl group with 3H and thymidine labeled on its carbon 2 with 14C were injected in 22 hepatectomized rats either 1 hr (when DNA synthesis is not increased) or 24 hr after the surgical procedure (when the rate of DNA synthesis is maximal). Liver samples taken 10, 30 and 120 min after injection showed that, in contrast to 3H-radioactivity, 14C-radioactivity measured in whole tissue allowed a clear discrimination between regenerating and nonregenerating livers. In addition, 14C-radioactivity measured in whole tissue of regenerating livers correlated with the DNA radioactivity 10, 30 and 120 min after injection of the tracer. In contrast, no such correlation was found with the methyl-labeled thymidine. Analysis of the radioactive material present in the non-DNA fraction using ion exchange disks and high-performance liquid chromatography showed that 2-C-labeled thymidine was incorporated into DNA without accumulation of labeled metabolites whereas, for the methyl-labeled thymidine, almost all radioactivity was related to degradative products. Therefore the evaluation of the liver regeneration with the 2-C-labeled thymidine, which does not require cellular fractionation, should be suited for noninvasive measurement with positron emission tomography.

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“…This fact suggests that the base components liberated by the decomposition of the extruded nuclei are reutilized by the erythroid precursors, because the introduced TDH3 will rapidly disappear from the circulating blood (10,11), and after about 50 h no labeling of the erythroid precursors younger than basophilic erythroblasts is expected, as the proerythroblasts mature to orthochromatic cells through four cell divisions (12) and the mitotic cycle of mammalian erythroblasts is reported to be less than 24 h by several investigators (7,(13)(14)(15)(16)(17).…”

Section: Discussionmentioning

confidence: 99%