The intention of this study was to correlate the retained volume at the end of defecography to certain defecographic findings and to the sense of incomplete emptying. In 170 defecographic series, the retained barium was estimated planimetrically. No particular defecographic finding determined a higher or lower amount of remaining volume, and the sense of incomplete evacuation did not depend on the amount of retained volume. Thresholds of urge and perception on anorectal manometry did not differ between patients with and without the feeling of incomplete evacuation. A rectocele, isolated or combined with an internal prolapse, caused the retained volume to be in the lowermost part of the rectum, whereas, in the case of an isolated intussusception, the remaining volume was located in the middle or higher part of the rectum. It is concluded that defecographic findings do not in general explain incomplete emptying or the sense of incomplete emptying, but they may determine the localization of the retained volume.

Interobserver agreement is good regarding the deformation of the rectum during defecography but not different from chance agreement regarding the completeness of evacuation.

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Summary Epidemiological and experimental studies suggest that androgens influence colonic carcinogenesis. We investigated the effects of hormonal manipulations (surgical and chemical castration, hormone substitution) on colonic tumour development, tumour and mucosal histopathology, and epithelial proliferation in macroscopically normal colonic mucosa in male rats, after induction of chemical colon carcinogenesis by subcutaneous injections of azoxymethane (AOM). Chemical castration with cyproterone acetate, but not surgical castration, resulted in increased colonic tumorigenesis, which was accompanied by decreased crypt length, decreased number of cells per crypt, and increased crypt epithelial mitotic index in the right colon. Chemically castrated rats also had crypt hyperplasia and increased numbers of dysplastic foci in the left colon which were not seen with surgical castration. By contrast, rats given testosterone after surgical castration showed decreased colonic tumorigenesis with an increased proportion of tumours in the left colon and lower percentage of tumours with invasion. The grossly normal mucosa of the testosterone-substituted castrated rats showed decreased crypt length in the right colon similar to the other groups of castrated rats, but no significant increase in mitotic index. Our results suggest that the anti-androgenic progestin cyproterone is a potent enhancer of colonic tumorigenesis and epithelial proliferative abnormalities after AOM administration. Exogenous testosterone after castration alters tumour distribution and characteristics and suppresses epithelial proliferative abnormalities. Finally, androgen effects on the colonic mucosa are more prominent in the right than in the left colon, suggesting different influences of hormones on the epithelium of these anatomical sites.An important role for androgens in colonic carcinogenesis in humans has been suggested on the basis of detection of specific receptor proteins in human colorectal tissue (Odagiri et al., 1984, Jacobson 1984. Chemically induced colonic carcinogenesis models in rats have been used to study modulators of colonic carcinogenesis (Autrup & Williams, 1983). Some authors reported specific androgen receptor proteins in chemically induced colonic tumours (Mehta et al., 1980;Krelenbaum et al., 1984;Jacobson, 1984). In addition, hormonal manipulations have been reported to influence tumour yield (Balish et al., 1977;Moon & Fricks, 1977;Mehta et al., 1978;Izbicki et al., 1983). These findings seemed to support a possible role of androgens in colonic carcinogenesis.Recently, we reported the effects of hormonal manipulations on chemically induced colonic carcinogenesis and androgen receptors in macroscopically normal mucosa and colonic tumours (Izbicki et al., 1986). In the present publication we present our evaluation of the mechanisms of the observed effects. Materials and methods Experimental protocolTwo hundred 8-week-old male Sprague-Dawley rats weighing 230-275 g (Wiga, Sulzfeld, FRG) were randomly allocated to five groups ...

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