Spectrofluorimetric determination of urinary p-aminobenzoic and p-aminosalicylic acids in the BT-PABA/PAS test of pancreatic function.

Spectrofluorimetry was investigated as an alternative to HPLC for determining p-aminobenzoic acid and p-aminosalicylic acid in the N-benzoyl-L-tyrosyl-p-aminobenzoic acid/p-aminosalicylic acid test of pancreatic exocrine function. Urine specimens were hydrolysed for 30 min in 4 M NaOH at 100 degrees C. The fluorescence of p-aminobenzoic acid was measured in dimethyl sulphoxide solution (lambda ex = 300 nm, lambda em = 340 nm) and that of p-aminosalicylic acid in sodium acetate buffer, pH 4.0 (lambda ex = 297 nm, lambda em = 394 nm). The linear range was 0.038-8 mM for p-aminobenzoic acid and 0.051-12 mM for p-aminosalicylic acid, within-batch precision was 2.2% and 5.5%, respectively, and the entire analysis could be completed within 40 min. Although not eliminated, drug interference was greatly reduced in comparison with colorimetry. In 23 consecutive pancreatic function tests there was an excellent correlation between the p-aminobenzoic acid/p-aminosalicylic acid excretion index obtained by fluorimetry and the results from HPLC analysis (y = 0.914x + 0.070, r = 0.987, p less than 0.001). The method is simple, cost-effective and may be particularly valuable in developing countries having a high incidence of chronic pancreatitis.

Lactase deficiency in the South African black population.

H2 breath analysis was carried out to determine the prevalence of lactase deficiency in different tribes of the South African Black population. Lactase deficiency was common (78%), despite the fact that two of the largest tribes (Zulu and Xhosa) are cattle herders and milk drinkers. This apparent anomaly is due to the consumption of a traditional fermented buttermilk, ("amasi" which has a low lactose content) instead of fresh milk. The most important reason for lactase deficiency, however, is that the South African Blacks originated in the West and Central African zone of nonmilking and took up dairying and milk use fairly recently. Thus they have not had enough time for genetic selection for lactase deficiency through life. The implications inherent in this study are that it would be more prudent to supply milk to developing countries in the form of a fermented milk product such as buttermilk. This is readily accepted by the Black population and would not be counter to accepted cultural practice.

PIP: H2 breath analysis was carried out to determine the prevalence of lactase deficiency in different tribes of the South African black population. Lactase deficiency was common (78%), despite the fact that 2 of the largest tribes (Zulu and Xhosa) are cattle herders and milk drinkers. This apparent anomaly is due to the consumption of a traditional fermented buttermilk (amasi) which has a low lactose content, instead of milk. The most important reason for lactase deficiency, however, is that the South African blacks originated in the West and Central African zone of nonmilking and took up dairying and milk use fairly recently. Thus they have not had enough time for genetic selection for lactase deficiency through life. Experience in Africa has shown that introducing skimmed milk causes diarrhea which may have catastrophic results in terms of mortality and morbidity. The implications inherent in this study are that it would be more prudent to supply milk to developing countries in the form of a fermented milk product such as buttermilk, prepared under traditional conditions and without refrigeration, since commercially prepared products do not have much less lactose and would also cause diarrhea in this population.