An unusual case of intestinal spirochaetosis is described. The rectum of a 34-year-old male, suffering from Crohn's disease and ankylosing spondylitis, was heavily infested by spirochaetes. Both absorptive and goblet cells were colonized. Spirochaetes were found not only on the luminal surface of these cells, but also within the cytoplasm, in occasional macrophages within the lamina propria and, even more surprisingly, within the occasional Schwann cell. The significance of these findings is discussed.

The effects of x-irradiation on the subcellular structure of the human urinary bladder were investigated by electron microscopic examination of biopsies taken during check cystoscopies from 25 patients between 1 month and 22 years after completion of a course of therapeutic radiation. All tissues of the bladder wall were damaged to some extent by the treatment. In the urothelium this was reflected by the development of more than the usual numbers of lysosomes and autophagic vacuoles in all cell layers. In the bladder wall, large often binucleate or multinucleate fibroblasts were prominent and persistent in all specimens and were associated with the development of progressive fibrosis. The vasculature and the muscle coats of the bladder wall were also damaged. In the blood vessels many endothelial cells were oedematous or necrotic and some intravascular coagulation was also observed. Smooth muscle cells became oedematous soon after irradiation, and after longer time intervals there was focal death and loss of individual muscle cells. The observed degeneration and extensive necrosis of the bladder wall, which involved severe destruction and disorganization of the muscular layers, is sufficient to explain the clinical sequelae of bladder irradiation, namely loss of elasticity, reduced capacity and incomplete micturition with residual urine.

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Summary.-Effects of X-irradiating the urinary bladder of female F344 rats with a single dose of 20 Gy were studied by light and electron microscopy. The animals were killed 1 week-20 months post-irradiation, and all tissues of the bladder wall were found to be affected by the irradiation.In the urothelium, damage was initially restricted to the basal cells but slowly extended to intermediate cells, and by 6 months post-irradiation the urothelium was focally hyperplastic. Twenty months post-irradiation, transitional-cell carcinomas were found in 10 of the surviving 17 animals (59%). The blood vessels in the bladder wall showed damage to both the endothelial cells and the smooth muscle. The fibroblasts in the connective tissue of the bladder wall appeared to show increased secretion after irradiation, and there was abundant collagen deposition, resulting in severe fibrosis of the bladder wall. After a latent period of a few months, focal degeneration and extensive necrosis of the smooth muscle cells were seen, leading to severe destruction and disorganization of the muscular coats of the bladder wall.Thus, a single dose of irradiation of 20 Gy was sufficient to produce severe fibrosis of the bladder wall with smooth muscle degeneration and to induce carcinoma of the urothelium in most of the treated animals within 20 months.

A 52 year old woman had autoimmune hepatitis and an increased concentration of serum carbohydrate antigen 19-9 (CA19-9). The origin of the raised CA19-9 was studied using immunohistochemistry. Liver biopsy section showed chronic active hepatitis with large numbers of proliferated bile ductules. Immunohistochemical analysis revealed that the proliferated bile ductule cells were positive for proliferating cell nuclear antigen (PCNA) and for CA19-9. It is speculated that the raised serum CA19-9 concentration was derived from proliferated bile ductule cells and these cells, which are positive for PCNA, may be able to produce high concentrations of CA19-9. (J Clin Pathol 1998;51:167-169)