Assessment of urine solute and matrix effects on the performance of an enzyme-linked immunosorbent assay for measurement of interleukin-6 in dog urine.
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Measurement of cytokine concentrations within body fluids is a means of recognizing subclinical and/or unresolved, infectious and inflammatory states in patients. In the urinary tract, such information may be useful for identifying patients with pyelonephritis, asymptomatic bacteriuria, recurrent infections, and cystitis. One such cytokine, interleukin-6 (IL-6), is recognized as a primary cytokine that is produced following exposure of the urothelium to bacterial virulence factors. Complicating reliable testing for this and other cytokines is the nature of urine itself. Urine varies widely in its composition as indicated by the range of pH and urine specific gravity (USG) observed in healthy patients. An additional variable is the protein and carbohydrate matrix capable of hindering immunologic testing modalities, such as enzyme-linked immunosorbent assays (ELISAs). The purpose of the current study was to examine the role of urine pH, USG, and matrix while optimizing a canine-specific chemiluminescent ELISA for the measurement of IL-6 in the urine of dogs. Urine spiked with IL-6 obtained maximal IL-6 quantitative recoveries of only 55 +/- 10% (mean +/- 1 standard deviation) when an ELISA optimized for cell culture supernatants was used. The urine matrix and variations in USG were determined to by contributing to this poor IL-6 recovery. Using specific matrix inhibitors and optimal dilutions improved the IL-6 quantitative recovery to 91 +/- 5%. Urine pH (5.5-9.5) had no effect. The current work underscores the importance of critically optimizing testing modalities for biomarkers, particularly if they are immunologic in origin. (+info)
Educational intervention on water intake improves hydration status and enhances exercise performance in athletic youth.
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A dipstick test combined with urine specific gravity improved the accuracy of proteinuria determination in pregnancy screening.
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Proteinuria screening using a semi-quantitative dipstick test of the spot urine in antenatal clinic is known to have high false-positive rates. The aim of this study was to assess availability of a dipstick test combined with the urine specific gravity for the determination of pathological proteinuria. A dipstick test was performed on 582 urine samples obtained from 283 pregnant women comprising 260 with normal blood pressure and 23 with pregnancy-induced hypertension. The urine protein (P) and creatinine (C) concentrations, specific gravity (SG), P/C ratio were determined, and compared with dipstick test results. The P concentration increased along the stepwise augmentations in dipstick test result. Frequencies of the urine samples with 0.265 or more P/C ratio were 0.7% with - dipstick test result, 0.7% with the +/- result, 3.3% with the 1+ result, and 88.9% with the >/=2+ result. However, if the urine specific gravity was low, frequencies of the high P/C ratio were 5.0% with +/- dipstick test result and 9.3% with the 1+ result. A dipstick test result of >/=2+ seems appropriate for a criterion of positive screening for pathological proteinuria in antenatal care. A dipstick test combined with the urine specific gravity may be useful for outpatient clinic screening. (+info)
The effect of hepatic lipase on coronary artery disease in humans is influenced by the underlying lipoprotein phenotype.
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