High fluid intake is the only preventive dietary measure that can be recommended to all patients with stones. However, the efficacy of dietary advice given to patients is unknown. We compared the impact of dietary advice to increase hydration (group 1, 57 patients) and of no dietary advice (group 2, 83 patients) on 24-hour urine volume. No significant difference was noted between groups 1 (1,624 ml.) and 2 (1,732 ml.). We then determined if urine specific gravity dipsticks could help patients increase the 24-hour urine volume. A correlation between 24-hour urine volume and mean urine specific gravity was performed on 263 randomly chosen patients. There was an inverse relationship between urine specific gravity and 24-hour urine volume with a correlation coefficient of 0.522 (y = 1.0207 - 0.00374x). Most patients (81.6%) with 24-hour urine volumes of less than 2.1 had a urine specific gravity of more than 1.010. The use of specific gravity dipsticks was evaluated as a tool to help 24 patients increase the 24-hour urine volume. The 24-hour urine volume increased significantly (p less than 0.05, paired Student's t test) in patients after feedback from specific gravity dipsticks when they were instructed to keep the urine specific gravity at or less than 1.010 (average 24-hour urine volume increased 192%). We conclude that dietary advice may be insufficient to modify fluid intake habits in stone patients. However, modifications of fluid intake habits may be improved by feedback from specific gravity dipsticks.
In an enzymatic assay for chloramphenicol, chloramphenicol acetyltransferase partially purified by affinity chromatography was used; [3H]acetyl coenzyme A served as a substrate. The purified enzyme was sensitive to p-hydroxymercuribenzoate but insensitive to 5,5'-dithio-bis-2-nitrobenzoic acid. The Michaelis-Menten constant was 10.5 muM. The operating range of the enzymatic assay was 0-30 mug/ml. The coefficient of variation was 1.9% at a concentration of 10 mug/ml. The method correlated well with a microbiological agar-paper disk method for mock unknown sera (r = 0.997) and serum or urine specimens (r = 0.993). The enzymatic assay was unaffected by the presence of any of 12 other antibiotics in tested serum.
Chloramphenicol acetyltransferase (CATase) was purified by affinity chromatography from Escherichia coli W677/HJR66, an R-factor-bearing mutant. The chloramphenicol aryl nitro group had to be reduced to an amino group prior to its coupling to the Sepharose 4B matrix. The single-step isolation procedure resulted in a 237-fold purification of CATase with over 65% recovery of the enzyme.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.