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Cell proliferation kinetics in the gastrointestinal tract of man
- I. Cell
, 1963
"... In studies of cell proliferation in the intestine of animals during the past few years, observations have been made that suggest points of interest concerning cell renewal in humans. In rodents, proliferating jejunal and colonic epithelial cells have mean generation times of about 12 to 18 hours, D ..."
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In studies of cell proliferation in the intestine of animals during the past few years, observations have been made that suggest points of interest concerning cell renewal in humans. In rodents, proliferating jejunal and colonic epithelial cells have mean generation times of about 12 to 18 hours, DNA synthesis (S phase) times of 5 to 8 hours, and premitosis (G2) and mitosis (M) times of 1 to 2 hours (1-3). Also, although many epithelial cells undergo a second generation cycle soon after mitosis, some cells appear to remain longer in interphase before dividing again (3). The rate of disappearance of labeled cells from the mucosa has also been shown to vary in different portions of the gastrointestinal tract in a number of species; e.g., more labeled cells are present in the colon and stomach 1 week after injection of H3-thymidine than in the duodenum or jejunum (4). In man, studies of mitotic indexes and radioautographic studies with H3-thymidine have suggested turnover times of intestinal epithelial cells in the order of several days (5-7). In the present study, we have measured the mean generation time and the phases of the proliferative cycle of human colonic and rectal epithelial cells after the administration of H3-thymidine. The results describe cell renewal and give data on the rate of disappearance of labeled cells from the mucosa of the human colon and rectum. METHODS Two patients with colostomies were studied. Both had resections of the descending colon for carcinoma of the rectum and liver metastases. The colostomies were composed of normal mucosa of the transverse colon. A * Supported in part by U. S. Public Health Service grants A-3165 and C-3697, and by The John A. Hartford Foundation, Inc., New York, N. Y. third patient with a carcinoma of the rectum 8 cm proximal to the anal orifice was studied. Although all patients had carcinoma and known metastases, and had recently lost weight, they were fairly well-nourished at the time of these studies.
Evidence for an essentially constant duration of DNA synthesis in renewing epithelia of the adult mouse
- J. Cell Biol
"... Tritiated thymidine autoradiography has been applied to several renewing epithelial tissues of the adult mouse in order to determine (a) the average time required for DNA synthesis; and (b) the temporal relationship of the synthesis period to the progenitor cycles of these populations. The average d ..."
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Cited by 14 (2 self)
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Tritiated thymidine autoradiography has been applied to several renewing epithelial tissues of the adult mouse in order to determine (a) the average time required for DNA synthesis; and (b) the temporal relationship of the synthesis period to the progenitor cycles of these populations. The average duration of DNA synthesis has been computed from curves describing the rates of appearance and disappearance of labeled metaphase figures in epithelia of colon, ileum, duodenum, esophagus, and oral cavity, in both normal and colchicine-treated animals. In general, application of colchicine does not significantly influence the derived values for DNA synthesis duration. The DNA synthetic time is remarkably similar in the tissues examined, despite wide differences in the times required for completion of the progenitor cycle (and for tissue renewal). Synthesis of DNA in these epithelial cells of the mouse requires approximately 7 hours. Agreement between this value and those derived by other investigators for mammalian cells in vivo and in vitro indicates that DNA synthetic time may be a temporal constant, of considerable potential utility to studies of cell proliferation. The advantages and shortcomings of this experimental approach to problems of cell population kinetics in vivo are discussed.
Proliferative activity of the lymphatic tissues of rats as studied with tritium-labeled thymidine
, 1964
"... Isotopic labeling of the DNA of blood cells has provided an important technique for obtaining information about the cytokinetics of white cells. It has been assumed that the DNA label is stable within a given lineage of cells. However, several papers have indicated reincorporation of tritiated thymi ..."
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Cited by 10 (1 self)
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Isotopic labeling of the DNA of blood cells has provided an important technique for obtaining information about the cytokinetics of white cells. It has been assumed that the DNA label is stable within a given lineage of cells. However, several papers have indicated reincorporation of tritiated thymidine (H3Tdr)-labeled deoxyribonucleic acid (H3DNA) of cells during catabolism by other proliferating cells. The tritiated thymidine is originally incorporated during DNA synthesis (I-6). Most interpretations of this finding have assumed that it is not the result of radiobiological artifact due to the isotope. Aside from the significance of this finding in terms of interpretation of data pertaining to cell renewal, life span, and possible transformation of blood cells into different morphological entities (7), the possibility of the DNA within cells being unstable has many other implications. The biochemistry of the transfer of DNA label remains to be elucidated. Hamilton (8), whose work in leukemic subjects led him to propose that DNA reutilization might occur within lymphatic tissue, believed that his data favored
The replication time and pattern of the liver cell in the growing rat
- J. Cell Biol
"... Three-week-old male rats of the Wistar strain were given tritiatcd thymidine, 1/~c/gm body weight, intrapcritoneally and were killed at intervals from 0.25 to 72 hours later. Autoradiographs were made from 5 # sections, stained by the Fculgcn method. The replication time and its component intervals ..."
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Three-week-old male rats of the Wistar strain were given tritiatcd thymidine, 1/~c/gm body weight, intrapcritoneally and were killed at intervals from 0.25 to 72 hours later. Autoradiographs were made from 5 # sections, stained by the Fculgcn method. The replication time and its component intervals were determined from the scoring of the labeling of interphase nuclei as well as of prophasc, metaphase, anaphase, and telophasc nuclei. Absorption of the intrapcritoneally injected label is rapid and is attended by "flash " labeling during intcrphase, The results show that at any one time about 4 per cent of the liver cells are synthesizing DNA preliminary to cell division. These cells alternate with waves of other cells and it is estimated that about 10 per cent of the liver cell population is engaged in cell duplication. The replication time is about 21.5 hours, and its component intervals occupy the following times: DNA synthesis, 9 hours; post-DNA synthesis gap, 0.50 hour; prophase, 1.3 hours; metaphase, 1.0 hour; anaphase, 0.4 hour; telophase, 0.3 hour; postmitosis gap, 9.0 hours. A group of liver cells has been recorded in at least 3 successive replication cycles.
THE REPLICATION TIME AND PATTERN OF CARCINOGEN--INDUCED
"... The replication time and pattern have been investigated in hepatoma cells induced by feeding 3'Me-DAB to male rats for 5 months. With the use of tritiated thymidine as a DNA label along with autoradiography, mitotic nuclear labeling has been studied 0.5 to 72 hours after the administration of t ..."
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Cited by 2 (0 self)
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The replication time and pattern have been investigated in hepatoma cells induced by feeding 3'Me-DAB to male rats for 5 months. With the use of tritiated thymidine as a DNA label along with autoradiography, mitotic nuclear labeling has been studied 0.5 to 72 hours after the administration of the label. The following time intervals have been estimated: replication time, 31 hours; DNA synthesis, 17 hours; G2 plus Mitosis, 2 hours; G1, 12 hours. Only about 8 per cent of the tumor cell (interphase) population is "flash " labeled, following a single dose of 50 gc of H3TDR. This group of cells has been followed through three cycles of division. The repeated rhythmic passage of tumor cells through cell division is similar to that previously reported for normal liver cells in the growing rat. However, tumor cells have longer replication and DNA synthesis times. In addition, the several time intervals studied vary more in the tumor cell population than they do in the growing normal cell population.
Cell proliferation of pericryptal fibroblasts in the rat colon mucosa. Gut
, 1979
"... SUMMARY The turnover of pericryptal fibroblasts in the rat colon mucosa was analysed after in vivo incorporation of tritiated thymidine. Thirty-six rats were serially killed one hour to 21 days after intraperitoneal injection ofthe radionuclide. At one hour, the labelling index of pericryptal fibrob ..."
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SUMMARY The turnover of pericryptal fibroblasts in the rat colon mucosa was analysed after in vivo incorporation of tritiated thymidine. Thirty-six rats were serially killed one hour to 21 days after intraperitoneal injection ofthe radionuclide. At one hour, the labelling index of pericryptal fibroblasts was only 2.44%; labelled fibroblasts were slightly predominant along the lower two-thirds of the crypts. Within 24 hours, most underwent at least one cell division. No migration was observed and a significant proportion of labelled fibroblasts was still present after three weeks. It is concluded that those fibroblasts constitute a slowly renewing cell population. The data failed to confirm the hy-pothesis of an 'en bloc ' migration of fibroblasts in synchrony with the epithelial cells. The intestinal epithelium is a tissue in which cell proliferation, differentiation, and migration occur throughout life. In the small intestine, proliferating cells are restricted to the crypts; the turnover time of the epithelial cell population is approximately 48 to 72 hours (Quastler and Sherman, 1959; Messier and Leblond, 1960; Cairnie et al., 1965). In the colon, proliferating cells are restricted to the lower two-thirds of the crypts and the turnover ranges between 34 and 140 hours (as estimated from data by
Isolation and Populations of
"... ABSTRACT-Colon epithelial cells of Sprague-Dawley rats were Isolated by the Incubation of everted colon sacs aerobically In Puck's Saline F containing 0.5 % hyaluronidase and a mixture of antibiotics (penicillin, streptomycin, and Funglzone). The com-plete removal of both mature absorptive and ..."
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ABSTRACT-Colon epithelial cells of Sprague-Dawley rats were Isolated by the Incubation of everted colon sacs aerobically In Puck's Saline F containing 0.5 % hyaluronidase and a mixture of antibiotics (penicillin, streptomycin, and Funglzone). The com-plete removal of both mature absorptive and deep cryptal pro-liferating cells required about 2 hours of Incubation. The yield of cells averaged about 153X10 "rat, with a standard deviation of 12.9X10'. Approximately 98 % of these cells excluded trypan blue and were capable of sustained oxidation of ["C]glucose. When these cells were placed In short-term culture for about 16 hours In Eagle's minimum essential medium containing 15 % calf serum and antibiotics (penicillin, streptomycin, and Funglzone), about 15±2 % attached to the surface of the culture plate. Attached cells showed a 15-fold higher Incorporation of ['H]thymldlne Into DNA
Spontaneous mutation in lac I transgenic mice: a comparison of tissues
"... The nature of spontaneous mutations in the lacl transgene of Big Blue ® mice was determined in selected tissues. The mutant frequencies ranged from 2.5 x 10~5 to 7.1 X 10~5 for liver, spleen, bladder, stomach, kidney, bone marrow, lung and skin. We also determined the DNA sequence alterations in the ..."
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The nature of spontaneous mutations in the lacl transgene of Big Blue ® mice was determined in selected tissues. The mutant frequencies ranged from 2.5 x 10~5 to 7.1 X 10~5 for liver, spleen, bladder, stomach, kidney, bone marrow, lung and skin. We also determined the DNA sequence alterations in the mutants recovered from these tissues. In all tissues the predominant class of mutations was G:C—>A:T transitions, most of which occurred at 5'-CpG-3 ' dinucleotide sequences. Bladder, kidney and skin display the highest contribution of G:C—»A:T transitions. The second most common class of mutations was G:C—>T:A transverslons. All other base substitution classes contributed <10 % each. Of the non-substitution events, the loss of a single base pair was the most frequently occurring event (<10%). The similarity of mutational spectra (in terms of kinds of mutations detected by the lacl transgenic system) in all tissues examined supports the idea that similar mutational pathways function hi these tissues in the absence of chemical or physical stimulus.
