Objective To review the performance of the IFCC enzyme reference methods in China laboratories and to evaluate the competence of enzyme reference measurement in China.Methods The Intemational Federation of Clinical Chemistry and Laboratory Medicine(IFCC)enzyme reference methods were performed in 8 China laboratories.Reference procedures were developed by each laboratory and the performances were evaluated.The Clinical and Laboratory Stadards Institute(CLSI)EP-5 protocol was used for the evaluation of precision and certified reference materials(CRMS)were used for the verification of trueness.Seven of the 8 laboratories participated in the 2006 IFCC external quality assessment program for reference laboratories(RELA)for the assessment of the measurement performance.Results Within-run CVs of less than 1.5%and between-run CVs of less than 2%were achieved bv all the China laboratories.Results on CRMs by some of the laboratories agreed with the certified value within the stated uncertainty.In the 2006 RELA,the averages and the interlaboratory CVs of the China laboratories were similar to those of international laboratories.Conclusion A preliminary enzyme reference method laboratory network has been established in China.

OBJECTIVETo investigate changes in gene expression that occur upon treatment with human umbilical cord mesenchymal stem cells (UC-MSCs) for hepatic cirrhosis using a rat model system.

METHODSHepatic cirrhosis was induced in Sprague-Dawley rats by subcutaneous injection of carbon tetrachloride and oral administration of alcohol.UC-MSCs were isolated from human umbilical cord and the cells' immunophenotype and differentiation towards osteogenic and adipogenic lineages were confirmed.The UC-MSC sample or vehicle alone (phosphate buffered saline, PBS) was transplanted by intravenous injection.Histopathological staining and serological testing were used to compare the liver morphology and function among the different groups.The gene expression in the PBS group and UC-MSC group were detected by gene microarray and differences between the groups were statistically analyzed by t-test.

RESULTSTransplantation of the UC-MSCs improved liver function in the hepatic cirrhosis rats.Comparison of the gene expression profiles of the PBS group and the UC-MSC group showed that the latter had up-regulation of the genes related to the complement and coagulation cascades and down-regulation of the genes related to cell proliferation, cell cycle, and collagen synthesis.

CONCLUSIONUC-MSC therapy might improve liver function in cirrhosis by increasing the expression of genes related to the complement and coagulation cascades and by decreasing genes involved in cell proliferation and collagen deposition.

Animals ; Carbon Tetrachloride ; Cell Differentiation ; Cell Proliferation ; Down-Regulation ; Gene Expression Profiling ; Humans ; Liver Cirrhosis ; Mesenchymal Stromal Cells ; Rats ; Rats, Sprague-Dawley ; Transcriptome ; Umbilical Cord ; Up-Regulation

Objective To study the effect of magnetic rewarming on the morphology and biomechanical properties of vitrified umbilical artery. Methods The vitrified umbilical artery was rewarmed by magnetothermal method and traditional water bath. The temperature distribution and stress in the solution system were analyzed, and the rewarming effect was evaluated by tissue staining and mechanical test. Results Compared with water bath rewarming, the temperature gradient and thermal stress generated by magnetic rewarming were smaller, which could effectively reduce the thermal stress damage during the rewarming stage and achieve rapid and uniform rewarming. Magnetic rewarming could effectively avoid umbilical artery fractures and micro-cracks. After rewarming, the extracellular matrix, collagen fibers, elastic fibers and muscle fibers of the umbilical artery were evenly distributed, which preserved the macro and micro structures of the umbilical artery. The umbilical artery showed different degrees of hardening after water bath and magnetic rewarming, but the elastic modulus and limit stress of the latter were not significantly different from those of fresh umbilical artery, and the latter had unidirectional stretching characteristics similar to that of fresh umbilical artery, showing good elasticity and toughness. Conclusions Compared with water bath rewarming, magnetothermal method can effectively reduce the damage of rewarming stage, ensure the macroscopic, microscopic structure integrity of umbilical artery and better biomechanical properties. The research findings provide important references for cryopreservation of large tissues or organs such as umbilical artery.

Objective Accurate measurement of aldosterone is critical in the diagnosis of primary aldosteronism. We compared the harmonization of three assays including isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) and two chemiluminescence immunoassays (CLIAs:system A and system B) for the aldosterone measurement. Methods A total of 45 plasma samples, 4 quality control materials, 5 lyophilized bovine serums, and 3 fresh frozen human serum pools were measured by three assays respectively. Based on CLSI EP15-A3 rule, the precision was assessed by coefficient of variance. Deming regression and Bland&Altman plots was performed for method comparison, and correlation coefficient was calculated for concordance (CCC). Results All three methods met the performance criteria based on desirable biological variation for precision (<7.35％). System A showed a relevantly good correlation and comparability with ID-LC/MS/MS (R2=0.985, CCC=0.967), while System B showed relevantly bad correlations and comparability with both System A (R2=0.538, CCC=0.605) and ID-LC/MS/MS (R2=0.547, CCC=0.528).. However, the average relevant bias of two CLIAs exceeded the bias requirement derived from biological variation (18.60％). Conclusion Significant differences were found in the measurement of plasma aldosterone using ID-LC-MS/MS and two CLIAs, which urges the establishment of traceability hierarchy and improvement of reagents' specificity for standardization of aldosterone measurement in clinical settings.

OBJECTIVE: To examine the level of occupational exposure to whole body vibration( WBV) in a hydroelectric power station,and evaluate its effects on workers' health. METHODS: A hydroelectric power station in Hangzhou City was chosen as study subject by using judgment sampling method. The level of WBV exposure to workers and high vibration level areas were measured,and the vibration frequency was analyzed. The comfort and allowing duration of occupational exposure in WBV exposed workers was evaluated. RESULTS: The median root-mean-square of accelerometer acceleration of WBV exposure in generator floor,turbines-floor,middle-floor,hydraulic floor of the hydroelectric power station were 0. 894,0. 995,1. 095 and 0. 904 m/s~2,respectively. The central frequency of WBV in this station was 1. 25 Hz. Among the 105 monitoring spots,8. 6% of WBV exposed workers of the spots did not perceive or feel uncomfortable,but 91. 4%of them felt uncomfortable or very uncomfortable. Only 12. 4% of the WBV exposed workers tolerated more than 8 hours of WBV occupational exposure. CONCLUSION: There is an occupational hazard of WBV in this hydroelectric power station.The low frequency vibration with central frequency below 1. 25 Hz is the key control point of the WBV of this hydroelectric power station.

Objective:To establish the allowable total error (TEa) of the national external quality assessment (EQA) program in line with the current quality level of serum folate measurement in China.Methods:The data of serum total folate test in the clinical laboratory of a hospital in Beijing in 2016 were collected, and the Stata SE 15 software was used for Monte Carlo simulation to obtain the false-negative rate under different bias and inaccuracy conditions. The Origin Pro 9.1 software was used to make the contour figure. The TEa of serum total folate test is derived based on the acceptable false-negative rate. National EQA data of serum total folate in 2020 were collected to calculate the pass rate of participating laboratories and the laboratory pass rate of quality control products at each level under the five TEa derived from the analysis performance on clinical outcomes, biological variation, and the evaluation criterion of national EQA.Results:Based on the influence of analytical performance on clinical outcomes, the TEa was 10%. Under this TEa, the pass rate of the first EQA program of serum total folate in 2020 was more than 80%, and the pass rate of the second time was 73.1%. Under the minimum (46.57%) and appropriate level of TEa (15.52%) derived from biological variation and national EQA evaluation criterion, the pass rate of serum total folate in the two EQA programs in 2020 exceeded 85%.Conclusion:The analytical performance of serum total folate in China cannot meet the requirements of TEa derived based on the effect of analytical performance on clinical outcomes. An appropriate level of TEa derived based on biological variation (15.52%) is suggested as the recommended criterion for the TEa of serum total folate test.