Volume Of Urine Sample Research Articles

Repressing Effects of Sodium Dodecyl Sulfate on Solvent-Gelatinization of Urine Samples

The present work aimed to use a small volume of solvent for extraction of a large volume of urine sample in order to reduce the increase in hazardous waste. Sodium dodecyl sulfate (SDS) was found to exert an ability to repress gelatinization of solvent, which could be caused by shaking a small volume of solvent with a large volume of urine sample. Use of SDS provided the following simple method. Filtrate (100ml) of a human urine sample (pH 9-10 or 3-4) was spiked with 100μl of 5% SDS solution, and shaken with 2.5ml of chloroform. The clear, separated chloroform layer was dried in a glass tube (2ml), and the residue dissolved in solvent (chloroform : 50μl) and subjected to analysis. This characteristic behavior of SDS for separation of clear chloroform was interpreted by hypotheses deduced from chemical equilibria among SDS, protein, and chloroform.

Method for the Analysis of Oxidized Nucleosides by Gas Chromatography Mass Spectrometry

A method for sensitive analysis of the oxidatively modified nucleosides 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 5-hydroxymethyl-2′-deoxyuridine (HMdU) is described. The method combines acetylation and pentafluorobenzylation of the nucleosides followed by analysis by gas chromatography/electron capture negative ion chemical ionization-mass spectrometry. The detection limits of the method for aqueous standards of HMdU and 8-OHdG were 12 and 18 fmol of starting material (signal-to-noise ratio, 3:1), respectively. The method was linear for 8-hydroxy-2′-deoxyguanosine over five orders of magnitude and gave satisfactory reproducibilities (intraassay RSD ≤ 5%) for the analysis of 8-OHdG in both aqueous standards and urine fortified at the level of 35 nM. The limit of detection for the analysis of 8-OHdG in urine was 1.8 pmol, corresponding to a level of 8-OHdG in urine of 35 nM (10 μg/liter) at a urine sample volume of 50 μl. Besides urine the method was applied to the analysis of 5-hydroxy-methyl-2′-deoxyuridine isolated from genomic DNA of Bacillus subtilis bacteriophage H1. Results obtained indicate that the method is potentially suitable for the determination of oxidized nucleosides in biological samples. The selectivity of the method should be enhanced in order to lower the limit of detection in biological samples.

Quantitative measurement of N-acetyl- l-aspartic acid in urine by gas chromatography with negative-ion chemical ionization mass spectrometry

A highly specific and sensitive assay for N-acetyl- l-aspartic acid has been developed. The trideuterated compound was synthesized and used as an internal standard for gas chromatography with negative-ion chemical ionization mass spectrometry. Urine samples were acidified and extracted with ethyl acetate, and the compounds converted into their pentafluorobenzyl ester derivatives. Under these conditions, sub-picogram amounts of the pure derivatives could be detected. Thus, only microlitre volumes of urine samples have to be processed to achieve reliable quantification of “basal” levels of N-acetyl- l-aspartic acid.

Determination of cadmium in urine by platform ET-AAS independent of matrix composition

The optimization of the heating conditions, absorbance profiles, the influence of different matrix composition and the effect of delivering different volumes of urine samples were examined in order to evaluate the use of simple aqueous standards for the determination of cadmium in urine samples, using atomic absorption spectrometry with electrothermal atomization and the L'vov platform. Three reference materials were analysed for cadmium by the proposed method. The results indicate that a direct and accurate determination of urine cadmium is possible by using simple aqueous calibration standards, independently of the composition of the urine matrix.

The Effect of Experimental Cystitis and Iatrogenic Blood Contamination on the Urine Protein/Creatinine Ratio in the Dog

The effect of experimentally induced cystitis and iatrogenic blood contamination on the urine protein/creatinine ratio (U P/C) was evaluated in 17 dogs. Before they were included in the study, all dogs were judged to be healthy on the basis of physical examination, serum concentrations of urea nitrogen and creatinine, complete urinalysis, and a U P/C less than 0.4. A single urine sample was contaminated with increasing quantities of canine fresh whole blood (PCV = 42%; total protein = 6.2 g/dl). When added blood was equal to or greater than 25% of the total urine sample volume, the U P/C exceeded 3.5, a finding consistent with nephrotic range proteinuria. When added blood was 10% of the total urine sample volume, the U P/C was less than 1.8. Eleven Beagles underwent routine laparotomy during which a cystotomy was done. The median U P/Cs on postoperative days 1 and 2 were significantly increased compared with preoperative values (P less than 0.05); no U P/C exceeded 2.0. Renal biopsies performed on postoperative day 3 eliminated renal proteinuria as a source of urine protein. Five dogs had bacterial cystitis experimentally induced. At 72 and 96 hours after bacterial inoculation, the median U P/Cs were significantly increased (P less than 0.05); individual values ranged from 1.5 to 40.8. Renal biopsies performed between 5 and 6 days after inoculation eliminated renal proteinuria as a source of urine protein. Cytologic evaluation of urine sediment in each group did not correlate with the magnitude of the increase in the U P/C. The U P/C significantly increased in each model of lower urinary tract inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Level of Human Growth Hormone (hGH) in Urine Determined by A Highly Specific and Sensitive Sandwich Enzyme Immunoassay

Abstract Levels of human growth hormone (hGH) in urine samples were determined by a highly specific and sensitive sandwich enzyme immunoassay, which had little cross-reaction with human luteinizing hormone, human follicle-stimulating hormone, human thyroid-stimulating hormone and human prolactin. The volume of urine samples used was 0.05 ml. Urine hGH levels in normal subjects, aged less than 2 yr, 2-5 yr, 6-15 yr and 28-35 yr (male) were 78-113, 19-51, 7.8-25 and 1.1-5.2 ng/g of creatinine, respectively. In dwarfism patients aged 6-15 yr, urine hGH levels were < 0.2-6.0 ng/g of creatinine.

A rapid high-performance analytical procedure with simultaneous voltammetric determination of toxic trace metals in urine

For the monitoring of toxic trace metals in urine a new high-performance trace analytical procedure with simultaneous voltammetric determination is presented. Particular emphasis has been placed on minimizing contamination by reducing the urine sample volume to 1 ml and consequently limiting the needed amount of HNO 3/HClO 4 and the duration (<20 min) of the wet digestion stage. The procedure consists of three stages. First 20 urine samples (1 ml each) are simultaneously freeze-dried overnight. They then require only a short wet digestion (HClO 4/HNO 3 2:1, 20 min, 210°). They are then adjusted to pH 4.5 with acetate buffer and the trace metals are determined simultaneously by differential pulse anodic-stripping voltammetry at the mercury film electrode, the quartz digestion vessel being used as the voltammetric cell. If precipitates occur in the acidified samples, their trace metal content can be determined in the same manner, avoiding the low results commonly obtained by other methods. The procedure has high sensitivity with fair to good precision, covers a determination range from the sub-μg/l. to the medium μg/l. level and lends itself to automation. It is cheaper and more accurate than atomic absorption. Thus the procedure provides important potentialities for surveillance of occupationally exposed persons as well as for extended ecotoxicological baseline studies in man and cattle.