Kinetics of Cell Populations in the Intestinal Epithelium of Mice after Partial-body Irradiations with X-rays and Neutrons

Shiragai, A; Sato, Fumiaki; Hiraoka, Takeshi; Inada, Tomohiro; Kawashima, K.; Matsuzawa, H

doi:10.1080/09553007614550431

Cited by 3 publications

(1 citation statement)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An isoeffect for clonogenic cell survival would then have a limited meaning, because what is hidden behind equal numbers is qualitatively different. This view is substantiated by dissimilarities in intestinal surface morphology [10] and in dynamics of changes in crypt and villus cell number [23] observed while comparing photon and neutron radiation. When instead of radiation, alkylating agents are used in gut microcolony assay, there seems to be much less of the differential killing [18], suggesting again, what is only to be expected, that because the mechanism of sterilization of cells within their heterogeneous population is different, the properties of survivors are by no means the same as those following irradiation.…”

mentioning

confidence: 76%

Effects of radiation on normal tissues: Hypothetical mechanisms and limitations of in situ assays of clonogenicity

Michałowski

1981

Radiat Environ Biophys

109

View full text Add to dashboard Cite

It is argued that proliferating normal tissues fall into two categories. In type H (for hierarchical) tissues, cells either multiply or perform tissue-specific functions. Sterilizing doses or radiation immediately initiate a gradual depopulation of irreversibly postmitotic, mature cells. The constant rate of functional cell depletion is given by physiological longevity of the cells. Consequently the onset of maximal depopulation is dose-independent and, after a range of radiation doses, the peak of milder damage is seen earlier than that of a more severe one. In type F (for flexible) tissues all cells are assumed to have the potential for proliferation and are also engaged in tissue-specific functions. Radiation leads to dose-dependent loss of the functional cells through their mitotic death, both immediately after exposure and during the next phase of increased compensatory proliferation resulting in accelerated expression of radiation damage ('avalanche'). Consequently the more severe damage following larger doses of radiation is seen earlier than the milder one produced with smaller doses. Assays of cell clonogenicity in vivo concern almost exclusively type H populations. The large radiation/drug/heat doses administered in these assays serve both to dilute the clonogenic cells by at least two orders of magnitude, and to produce a measurable response. When comparing two agents or interpreting their combined action it is advisable to ensure that the dilution step yields qualitatively comparable samples of clonogenic cells to be then characterized in terms of dose-survival curve parameters.

show abstract

mentioning

confidence: 76%