Influence of coffee intake on urinary hippuric acid concentration.
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Intake of foods and drinks containing benzoic acid influences the urinary hippuric acid (HA) concentration, which is used to monitor toluene exposure in Japan. Therefore, it is necessary to control the intake of benzoic acid before urine collection. Recently, some reports have suggested that components of coffee, such as chlorogenic, caffeic, and quinic acids are metabolized to HA. In this study, we evaluated the influence of coffee intake on the urinary HA concentration in toluene-nonexposed workers who had controlled their benzoic acid intake, and investigated which components of coffee influenced the urinary HA concentration. We collected urine from 15 healthy men who did not handle toluene during working hours, after they had consumed coffee, and we measured their urinary HA concentrations; the benzoic acid intake was controlled in these participants during the study period. The levels of chlorogenic, caffeic, and quinic acids in coffee were analyzed by LC-MS/MS. Urinary HA concentration increased significantly with increasing coffee consumption. Spectrophotometric LC-MS/MS analysis of coffee indicated that it contained chlorogenic and quinic acids at relatively high concentrations but did not contain benzoic acid. Our findings suggest that toluene exposure in coffee-consuming workers may be overestimated. (+info)
Urinary 8-hydroxydeoxyguanosine as a biomarker of oxidative DNA damage in workers exposed to ethylbenzene.
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A comparative study of renal scintigraphy and clearance with technetium-99m-MAG3 and iodine-123-hippurate in patients with renal disorders.
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The aim of this study was to compare kit prepared technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) with our routine radiopharmaceutical, iodine-123-hippurate our routine radiopharmaceutical, iodine-123-hippurate ([123I]OIH) for renal dynamic scintigraphy. Seventeen patients with different nephrologic disorders or hypertension were first studied with OIH and then reinvestigated with MAG3 2-8 days later. Renal MAG3 gamma camera images were almost identical with those of OIH except for higher (p less than 0.01) liver-to-background ratios at 20 min postinjection, irrespective of kidney function. Urinary peristalsis was visible longer and more clearly in the MAG3 studies. MAG3 and OIH renograms showed identical relative kidney uptake (r = 0.99), but elimination of MAG3 from the kidneys was slower (p less than 0.01). The plasma clearance of MAG3 was lower than that of OIH, but correlated (r = 0.92) significantly. The plasma distribution volume and content in blood cells was lower (p less than 0.01), but the binding of MAG3 to plasma proteins was higher, 90%, as compared with 74% for OIH, p less than 0.01. Urinary excretion expressed as a percent of the given dose 60 min after injection was the same for the two substances. Thus, there are some significant differences in the renal handling, plasma distribution, and cell penetration between MAG3 and [123I]OIH. MAG3, however, seems to have particular qualifications as a radionuclide for dynamic renal scintigraphy, especially in patients who require acute investigations or in those with low renal function. (+info)
Identification of urinary metabolites that distinguish membranous lupus nephritis from proliferative lupus nephritis and focal segmental glomerulosclerosis.
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