Between 1982 and 1989, the seven day retention of 75SeHCAT was measured in 181 patients with chronic diarrhoea that remained unexplained after full investigation. Altogether 121 of the 181 had a seven day 75SeHCAT retention ¢15% and thus had no evidence of abnormal bile acid turnover. Twenty one had a seven day 75SeHCAT retention : 10% but <15%. Their clinical features were typical of the irritable bowel syndrome, and none ofeight treated with cholestyramine showed symptomatic improvement. Sixteen patients had a seven day retention ¢"5% and <10%, six of whom had improved symptoms after treatment with bile acid chelating agents. The remaining 23 patients had a 75SeHCAT retention of <5% at seven days and responded to bile acid chelators. This group had a characteristic illness with intermittent watery diarrhoea, but no constitutional upset. It was not possible to distinguish the patients with bile acid malabsorption exclusively on the basis of the clinical symptoms and investigations, other than "SeHCAT retention. We conclude that the measurement of 75SeHCAT retention is useful, appropriate, and necessary in patients with unexplained chronic diarrhoea.

SUMMARY Oesophageal transit and gastric emptying of liquids and solids was measured in eight normal subjects with a single test meal containing In'"3 labelled water and an omelette labelled with Tc" sulphur colloid. Each volunteer was studied, basally, whilst continuously smoking, and while chewing nicotine gum. Neither liquid, nor solid oesophageal transit were affected by smoking, or gum. Liquid gastric emptying occurred exponentially and clearance was not affected by smoking nor gum (mean basal t½/2 17-4 (2-7) (SEM) min, smoking t/2 16-6 (7 4) min, gum t/2 12-5 (2-9) min). Gastric emptying of solid had three components. An initial mean lag phase increased from 17 5 (2 7) min, to 27-5 (6-1) min (p<005) during smoking, but was not prolonged by nicotine gum (17-5 (1 1) min). A subsequent linear emptying phase was also slowed by smoking from a mean of 1-01 (0415)% min to 0-80 (0-15)% min (p<0 05), but was not affected by nicotine gum, 1-06 (0-2)% min. A third complex phase ofsolid gastric emptying was not analysed. Smoking delays gastric emptying ofsolids, but not liquids; nicotine is not responsible for this effect. This observation may partly explain the adverse effect of smoking in patients with gastro-oesophageal reflux.The effects of cigarette smoking upon gastroduodenal secretion are controversial. Smoking has been reported to decrease' and to increase2 gastric acid and pepsin secretion. Smoking decreases mean duodenal pH by inhibiting duodenal mucosal3 and pancreatic bicarbonate4 secretion. These effects may explain the known adverse effects of smoking upon the natural history of peptic ulcer.5 Patients with symptomatic gastro-oesophageal reflux also tend to improve when they stop smoking. The observations that gastro-oesophageal emptying tends to be slow in patients with gastro-oesophageal reflux6 and in peptic ulcers,7 and that drugs which accelerate gastric emptying improve symptoms, suggest that abnormal oesophagogastric motility may be a relevant factor in these diseases. This has prompted us to assess the effects of smoking upon oesophageal and gastric emptying of liquids and solids. To our knowledge this has not previously been studied in man. Methods SUBJECTSEight healthy male volunteers aged 21-58 years, who regularly smoked 20-40 cigarettes daily were studied.

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The cause of intractable chronic diarrhoea was found to be malabsorption of bile acid in five out of 42 patients thought to have the irritable bowel syndrome, six out of 29 patients with persistent diarrhoea after surgery for peptic ulcer, 23 who had undergone small bowel resection, and two others. Specific treatment brought symptomatic relief. The diagnosis was established by measuring the proportion of SeHCAT, a synthetic bile salt, retained one week after oral administration of a tracer dose of less than 100 Fkg of the compound labelled with 40 kBq (1 .Ci) of selenium-75.These results indicate that malabsorption of bile acid is a more common cause of chronic diarrhoea than is generally appreciated. Measurement of retention of SeHCAT is a simple, accurate, and acceptable means of establishing the diagnosis of this debilitating but treatable condition. IntroductionThe bile acids are a closely related group of naturally occurring detergents that play an essential part in the absorption of fats and fat soluble compounds and are largely reabsorbed unchanged before reaching the caecum. Certain bile acids have a direct effect on the colonic mucosa, controlling the rate of sodium absorption and water secretion. When in abnormally high concentration in the colon they cause diarrhoea, and deficiency results in constipation.'

The different patterns of bone metastasis, metastatic load and their prognostic significance were examined in a consecutive series of 169 men with prostatic cancer and bone metastasis at presentation. Patients with an isolated metastasis in the pelvis or dorsal vertebrae had a better prognosis than those whose metastases were either diffuse or involved more distal sites such as the skull or the sternum, although all of these patients were classified as having M1 disease. Bone metastasis involving an area equivalent to 1 vertebral body equalled a metastatic load of 2. Based on their total metastatic load, 3 prognostic groups were identified with significant differences in case-specific survival despite receiving the same hormonal treatment. When comparing the potential efficacy of various treatments one must stratify the metastatic load, which is a powerful prognostic indicator of the outcome in patients with metastatic carcinoma of the prostate.

The potential value of indium-labelled bleomycin as a diagnostic scanning agent has been investigated in patients with a variety of malignant neoplasms involving the thorax, abdomen or pelvis. Sixty-five patients were scanned on 72 occasions, the optimum time to perform the examination being 72 hours after the intravenous injection of 2 mCi 111-In chelated to 2 mg bleomycin. Tumour uptake was visualized in 53 out of 62 scans in which tumour was present, but the extent of tumour was underestimated in seven cases, and over-estimated in five others. The latter were mostly due to uptake in infective lesions. These results indicate that the situations in which indium bleomycin is most likely to provide clinically relevant information are the distinction between recurrent tumour and post-radiotherapy changes in the thorax and pelvis, the diagnosis of recurrent carcinoma within the pelvis, and the distinction between bony metastases from carcinoma of the prostate and Paget's disease. Further clinical trials are necessary to assess these situations.

Patients with Crohn's disease who suffer from longstanding diarrhoea that does not respond to conventional treatment pose a common clinical problem. Bile acid malabsorption is a possible cause, although its prevalence and clinical importance is unclear. This paper explores the clinical indications for referring

Radioisotope scintigraphy of the kidney and intravenous urography have been compared in 79 children with bacteriologically proven urinary tract infections, followed up over a period of between one and four years. Both techniques were in agreement as to the presence or absence of an abnormality, and the extent of any abnormality present, in 93.5% of the kidneys studied. There was a discrepancy in ten kidneys. Excretion urography has a sensitivity of 0.86 and a specificity of 0.92 in the detection of pyelonephritic scarring in children. Radioisotope scintigraphy has a sensitivity of 0.96 and a specificity of 0.98. It is therefore concluded that radioisotope scintigraphy is the preferred technique.