Potential errors in the measurement of total protein in male rat urine using test strips

Widely differing results were obtained for urinary protein determinations in male rats using 2 test strips and a quantitative Coomassie Blue sodium dodecyl sulphate method. A comparison of the sensitivity of the protein methods with respect to rat albumin and alpha 2U globulin was made; both test strips were found to be relatively insensitive to the presence of alpha 2U globulin. Resultant limitations of test strips in monitoring adult male rat urine protein concentrations are discussed.     

A modified method for the estimation of pregnanediol, pregnanetriol and seven common 17-ketosteroids in urine by gas-liquid chromatography

A method is described for simultaneous determination of seven common urinary 17-ketosteroids, pregnanediol (5β-pregnane- 3α, 20α-diol) and pregnanetriol (5β-pregnane-3α,17α,20α-triol) by gas-liquid chromatography. The essential steps include hydrolysis of conjugates by an extract from $\text{Helix}$$\text{pomatia}$, use of 5β-cholestan-3α-ol as an internal standard, silylation and gas chromatography using 3% XE-60 as a stationary phase. The chromatograms were clear and the peaks easily identifiable. Laborious purification procedures were not necessary. 5β-pregnane-3α,20α-diol and 5β-pregnane-3α, 17α,20α-triol were measured in 22 adult males and 17 adult females. The subjects were trained hospital personnel, healthy and without medications. The results, in general, were in agreement with those reported by others.     

Enzyme immunoassay for the measurement of 17alpha-estradiol 17-N-acetylglucosaminide in rabbit urine.

17alpha-estradiol 17-N-acetylglucosaminide (17alphaE2 17NAG) is an estrogen metabolite hitherto obtained only in rabbits. To gain insight into this unique conjugate, an enzyme immunoassay (EIA) was established by using antiserum elicited against 3-[3-(1-carboxypropyl)] ether of 17alphaE2 17NAG-bovine serum albumin conjugate; horseradish peroxidase, as a label; and 3,3',5,5'-tetramethylbenzidine, as a chromogen. The method proved to be specific, and the detection range of the assay was 0.20-10.00 ng/ml. A proposed double conjugate, 3-glucuronide of 17alphaE2 17NAG, was synthesized to validate the EIA. The EIA was applied to the determination of the urinary level of 17alphaE2 17NAG in male and female (pregnant and non-pregnant) rabbits with and without beta-glucuronidase-sulfatase preparation from Helix pomatia. The results showed that 17alphaE2 17NAG was mainly excreted as a double conjugate (17alphaE2 17NAG 3-glucuronide and/or 3-sulfate) and that its level varies during pregnancy.     

Sensitive estimation of total cholesterol in blood using Au nanowires based micro-fluidic platform

Determination of cholesterol level in blood is important in clinical applications. In this work, modified Au nanowires-electrochemical biosensor based on MEMS micro-fluidic platform is proposed for estimating total cholesterol in blood. This sensor consists of "aligned" Au nanowires as working electrode, platinum counter electrode deposited on the silicon platform and Ag/AgCl (3M KCl) reference electrode. The "aligned" Au nanowires are immobilized with cholesterol oxidase and cholesterol esterase using specific covalent chemistry. Further, Au nanowires promotes better electron transfer between the enzymes and electrodes, because of their large surface to volume ratio, small diffusion time, large electrical conductivity and their aligned nature. The modified Au nanowires showed a stable calibration line and a quasi-linear relationship between cholesterol level and current response in the range of 1-6 mM (in steps of 1 mM over the baseline blood serum). The sensitivity of the modified electrode was found to be about 69 nA/mM with good storage and interference stability.