An on-line solid phase extraction procedure for the routine quantification of urinary methylmalonic acid by liquid chromatography-tandem mass spectrometry

Background: The goal of this study was to develop and to validate an improved isotope-dilution-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of methylmalonic acid (MMA) in urine. Methods: A previously described sample preparation protocol requires two solvent extraction steps, including evaporation. The first extraction is to extract the analyte from the sample, and second occurs following derivatization of the extract. In the method described here, the second evaporation step was substituted by on-line solid phase extraction employing column-switching and a permanent co-polymer based extraction cartridge. A standard validation protocol was applied to investigate the performance of the method. Results: The method was found to be linear in the clinically relevant range of concentrations (6-100 mu mol/L). Total coefficients of variation were below 10% and inaccuracy was <10% for quality control samples at three concentrations. Conclusions: By omitting one evaporation step, the semi-automated method described in this article enables for more convenient work-flow in the quantification of urinary MMA compared to the previous protocol. This is of relevance for MMA measurement in the routine clinical laboratory setting. Validation demonstrated acceptable analytical performance. Clin Chem Lab Med 2010;48:1647-50

Evaluation of dipstick analysis among elderly residents to detect bacteriuria: a cross-sectional study in 32 nursing homes

Background: Up to half the residents of nursing homes for the elderly have asymptomatic bacteriuria (ABU), which should not be treated with antibiotics. Thus, it is difficult to know if new symptoms in residents with bacteriuria are caused by urinary tract infection (UTI), or if bacteriuria only represents an ABU. This is especially difficult in the presence of non-urinary tract specific symptoms. The diagnostic uncertainty is likely to generate significant overtreatment with UTI antibiotics. Aim: The general aim was to clarify the association between symptoms, bacteriuria, dipstick urinalysis and urine Interleukin-6 (IL-6) among nursing home residents to improve the diagnostic procedure of a suspected lower UTI. Methods: In 2003 a study protocol including newly onset symptoms was completed, and single voided urine specimens collected for dipstick urinalysis and cultures from 651 residents of 32 participating Swedish nursing homes for the elderly. This data was used for a study of dipstick urinalysis (Paper I) and for a study of nonspecific symptoms and bacteriuria (Paper II). In 2012, similar data was collected for 421 elderly residents of 22 nursing homes, which also included an analysis of IL-6 in urine and urine specimens from another 59 residents with urinary catheters. The association between bacteriuria, IL-6 in urine, dipstick urinalysis and newly onset symptoms was analysed (Paper III). Antimicrobial resistance rates were described among residents of nursing homes in 2012 and compared with those from 2003 (Paper IV). Results: Paper I: The negative predictive value for predicting absence of bacteriuria was 88 (84-92)% when dipstick urinalysis for nitrite and leukocyte esterase were simultaneously negative. A positive dipstick or any combination thereof could not sufficiently predict bacteriuria. Papers II-III: New or increased nonspecific symptoms were common among elderly residents of nursing homes. Residents without nonspecific symptoms had positive urine cultures as often as those with nonspecific symptoms with a duration of up to one month. Paper III: Residents with positive urine cultures had higher concentrations of IL-6 in the urine. However, among residents with positive urine cultures there were no differences in IL-6 concentrations or dipstick findings between those with or without nonspecific symptoms. Paper IV: The average rates of antimicrobial resistance were low and did not increase between 2003 and 2012 in Escherichia coli (E. coli) urinary isolates among Swedish nursing home residents. Any antibiotic treatment during the last month and hospitalization during the last six months predicted higher resistance rates among E. coli. Conclusions: Nonspecific symptoms among elderly residents of nursing homes are unlikely to be caused by bacteria in the urine. Therefore, dipstick urinalysis, IL-6 in the urine and urine cultures are of little or no value in clarifying the aetiology of nonspecific symptoms. If there is a reason for testing for bacteriuria, dipstick urinalysis for nitrite and leukocyte esterase can rule out but cannot reliably rule in bacteriuria. Antimicrobial resistance in urinary pathogens among Swedish nursing home residents remained low. It is important to use antibiotics rationally to preserve the effectiveness of antibiotics

Metals detected by ICP/MS in wound tissue of war injuries without fragments in Gaza

<p>Abstract</p> <p>Background</p> <p>The amount and identity of metals incorporated into "weapons without fragments" remain undisclosed to health personnel. This poses a long-term risk of assumption and contributes to additional hazards for victims because of increased difficulties with clinical management. We assessed if there was evidence that metals are embedded in "wounds without fragments" of victims of the Israeli military operations in Gaza in 2006 and 2009.</p> <p>Methods</p> <p>Biopsies of "wounds without fragments" from clinically classified injuries, amputation (A), charred (C), burns (B), multiple piercing wounds by White Phosphorus (WP) (M), were analyzed by ICP/MS for content in 32 metals.</p> <p>Results</p> <p>Toxic and carcinogenic metals were detected in folds over control tissues in wound tissues from all injuries: in A and C wounds (Al, Ti, Cu, Sr, Ba, Co, Hg, V, Cs and Sn), in M wounds (Al, Ti, Cu, Sr, Ba, Co and Hg) and in B wounds (Co, Hg, Cs, and Sn); Pb and U in wounds of all classes; B, As, Mn, Rb, Cd, Cr, Zn in wounds of all classes, but M; Ni was in wounds of class A. Kind and amounts of metals correlate with clinical classification of injuries, exposing a specific metal signature, similar for 2006 and 2009 samples.</p> <p>Conclusions</p> <p>The presence of toxic and carcinogenic metals in wound tissue is indicative of the presence in weapon inducing the injury. Metal contamination of wounds carries unknown long term risks for survivors, and can imply effects on populations from environmental contamination. We discuss remediation strategies, and believe that these data suggest the need for epidemiological and environmental surveys.</p