Effects of Single Thoracic X-Ray Exposure in Rats

The influence of a seventy-two hour gap on the acute response of mouse skin and oesophagus

“…In our studies, although body weight loss and not lethality was chosen as the end-point, some animals died or were sacrificed because of unacceptable general conditions. These deaths occurred over a period of time similar to that reported by Kurohara and Casarett (1972) and Phillips and Ross (1974) and we saw no evidence of gastric or duodenal ulcers in these animals. Using weight loss as an end-point, we previously obtained well defined dose-response relationships for different fractionation schedules and radiomodifiers (Hirn-Stadler et al, in preparation).…”

“…Denudation and thinning of the epithelium was followed, 1-2 weeks later, by foci of proliferating basal cells and inflammatory infiltrate in the submucosa (Phillips & Ross, 1974). Areas of denudation were seen to coexist with areas of regeneration and these structural changes coincided well with changes in body weight and lethality (Kurohara & Casarett, 1972;Phillips & Margolis, 1972;Phillips & Ross, 1974). Proliferation studies on mouse skin indicate that repopulation of mouse oesophageal epithelium, after fractionated treatments, would start later rather than earlier than the time scale seen with large single doses (Denekamp, 1973;Tsang et al, 1990).…”

“…Probably, insertion of an early gap prevents the cells distributing themselves into more sensitive phases of the cell cycle and hence a slightly more resistant response was obtained. Regeneration in the oesophagus commences 7-14 days after a single dose of X rays (Kurohara & Casarett, 1972;Phillips & Ross, 1974). A dose > 20 Gy to the whole thorax produced a loss of proliferating cells in the basal layer of the epithelium, which led, 3-5 days after, to progressive and marked reduction of the differentiated squamous cells and of the keratin layer.…”

“…Decreased food intake, body weight loss and lethality after whole thorax irradiation in rodents have all been shown to be caused primarily by acute and subacute oesophageal damage and to be good indicators of oesophageal response (Kurohara & Casarett, 1972;Phillips & Margolis, 1972;Phillips & Ross, 1974). It was shown that lethality due to epithelial denudation occurred over a well denned period of time, with dehydration and starvation as the main cause of death, and no evidence of mediastinitis and/or oesophageal perforation was seen (Phillips & Ross, 1974).…”

Response of the mouse mediastinum to single and fractionated X-rays

“…Although decreased food intake and body weight loss, after whole thorax irradiation, were shown to be caused primarily by acute and subacute oesophageal damage (Kurohara & Casarett, 1972), animal lethality was chosen subsequently as the end-point for acute oesophagi tis (Phillips & Margolis, 1972;Phillips & Ross, 1974;Hornsey & Field, 1979). It was shown that lethality, due to epithelial denudation, occurred over a well defined period of time with dehydration and starvation being the main cause of death in the animals before lung damage became the cause of death (Phillips & Margolis, 1972;Phillips & Ross, 1974).…”