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dc.contributor.authorPotten, Christopher S
dc.contributor.authorGrant, H K
dc.date.accessioned2010-02-23T13:14:47Z
dc.date.available2010-02-23T13:14:47Z
dc.date.issued1998-10
dc.identifier.citationThe relationship between ionizing radiation-induced apoptosis and stem cells in the small and large intestine. 1998, 78 (8):993-1003 Br. J. Canceren
dc.identifier.issn0007-0920
dc.identifier.pmid9792141
dc.identifier.urihttp://hdl.handle.net/10541/92719
dc.description.abstractApoptosis is observed in the crypts of the small intestine of healthy animals and man (spontaneous apoptosis). The levels can be dramatically elevated 3-6 h following ionizing radiation exposure. Both the spontaneous and radiation-induced apoptosis in the small intestine crypts are most frequently observed at the positions in the crypt associated with stem cells (about four cell positions from the base of the crypt). The number of apoptotic deaths can be counted in routine histological preparations, but interpretation of the counts is complicated by numerous factors. However, recording the number of cells containing one or more apoptotic fragments in crypt sections provides a good estimate for the absolute number of cell deaths in crypts. Similarities are noted in the frequency and cell positional relationship of radiation-induced apoptosis in the small intestine of various strains of mice and one strain of rat. Apoptosis in the large intestine is generally lower in frequency than in the small intestine and, for the mid-colonic and rectal regions, has a different cell positional frequency distribution, with the highest apoptotic yield at the crypt base. The caecal colon has a pattern of apoptotic distribution more similar to that in the small intestine. After exposure to 1 Gy ionizing radiation, the maximum apoptotic yield occurs over a period of 3-6 h in the small intestine. There is some unexplained variability in the values between groups of mice and between different mouse strains. After 8 Gy, the yield remains elevated for several days, however a similar maximum yield is still observed at the early times. In mouse large intestine and rat small intestine, the yield continues to rise until about 6 Gy in mouse large intestine and until at least 10 Gy in rat small intestine. Spontaneous apoptosis is interpreted as part of the homeostatic mechanism regulating stem cell numbers. About 1.6 cells per crypt are dying at any one time. Following irradiation, there is an apparent relationship between mitotic and apoptotic levels, suggesting that these processes are linked. The dose-response relationship suggests that there are about six apoptosis-susceptible cells in crypts of the small intestine, with about 2-4 of these occurring at cell positions in which there are other more resistant clonogenic cells. In the large intestine, the position of these apoptosis-susceptible cells varies with region, but the numbers are similar.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshApoptosis
dc.subject.meshDose-Response Relationship, Radiation
dc.subject.meshGamma Rays
dc.subject.meshIntestine, Large
dc.subject.meshIntestine, Small
dc.subject.meshMale
dc.subject.meshMice
dc.subject.meshMice, Inbred Strains
dc.subject.meshMitotic Index
dc.subject.meshRats
dc.subject.meshRats, Wistar
dc.subject.meshStem Cells
dc.titleThe relationship between ionizing radiation-induced apoptosis and stem cells in the small and large intestine.en
dc.typeArticleen
dc.contributor.departmentEpithelial Biology CRC Group, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester, UK.en
dc.identifier.journalBritish Journal of Canceren
html.description.abstractApoptosis is observed in the crypts of the small intestine of healthy animals and man (spontaneous apoptosis). The levels can be dramatically elevated 3-6 h following ionizing radiation exposure. Both the spontaneous and radiation-induced apoptosis in the small intestine crypts are most frequently observed at the positions in the crypt associated with stem cells (about four cell positions from the base of the crypt). The number of apoptotic deaths can be counted in routine histological preparations, but interpretation of the counts is complicated by numerous factors. However, recording the number of cells containing one or more apoptotic fragments in crypt sections provides a good estimate for the absolute number of cell deaths in crypts. Similarities are noted in the frequency and cell positional relationship of radiation-induced apoptosis in the small intestine of various strains of mice and one strain of rat. Apoptosis in the large intestine is generally lower in frequency than in the small intestine and, for the mid-colonic and rectal regions, has a different cell positional frequency distribution, with the highest apoptotic yield at the crypt base. The caecal colon has a pattern of apoptotic distribution more similar to that in the small intestine. After exposure to 1 Gy ionizing radiation, the maximum apoptotic yield occurs over a period of 3-6 h in the small intestine. There is some unexplained variability in the values between groups of mice and between different mouse strains. After 8 Gy, the yield remains elevated for several days, however a similar maximum yield is still observed at the early times. In mouse large intestine and rat small intestine, the yield continues to rise until about 6 Gy in mouse large intestine and until at least 10 Gy in rat small intestine. Spontaneous apoptosis is interpreted as part of the homeostatic mechanism regulating stem cell numbers. About 1.6 cells per crypt are dying at any one time. Following irradiation, there is an apparent relationship between mitotic and apoptotic levels, suggesting that these processes are linked. The dose-response relationship suggests that there are about six apoptosis-susceptible cells in crypts of the small intestine, with about 2-4 of these occurring at cell positions in which there are other more resistant clonogenic cells. In the large intestine, the position of these apoptosis-susceptible cells varies with region, but the numbers are similar.


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