In order to determine the value of 24 h urine nitrogen (N) excretion as a way of validating dietary methods of measuring protein intake in individuals, daily N intake and excretion has been measured in eight healthy subjects while consuming their usual, varying, diets for 28 days. Daily duplicates of all food eaten were obtained and consecutive 24 h collections of urine and feces were made throughout and analyzed for N by the Kjeldahl method. The completeness of the 24 h urine collections was verified by the use of PABA and of feces by radiopaque pellets. N losses in blood and from the skin were measured. The within person variation in dietary intake ranged from 14 to 26% (coefficient of variation, CV) while urine N was more constant, varying from 11 to 18% (CV) within individuals. In these subjects eight 24 h urine collections, verified for their completeness, were sufficient to estimate dietary N intake to within 81 +/- 5% (SD) as assessed by 18 day dietary records.
SummarySeven women spent an average of 127 days in hospital and were extensively investigated, including a laparotomy, before their complaints of abdominal pain, diarrhoea, and weight loss were shown to be due to excessive taking of laxatives. All denied taking laxatives and in none were the characteristic features of the effects of cathartics on the colon seen on sigmoidoscopy or radiological examination.Hypokalaemia and other electrolyte abnormalities were common and were thought to be due to a combination of severe diarrhoea and vomiting. The rectal mucosa was seen to be abnormal on biopsy only in the three patients who had taken senna preparations. The diagnosis was not easy and was finally established either by analysis of the urine and stools or by searching the patienes ward locker.
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