Objective To compare the concordance of five automated 25OHD immunoassays with liquid chromatography tandem mass spectrometry method ( LC-MS/MS) .Methods During May to July in 2014, 245 clinical serum samples that requested 25OHD tests were selected, with a total 25OHD range of 2.8 ng/ml-64.0 ng/ml, in which 154 samples did not contain 25OHD2 and 91 samples contains both 25OHD2 and 25OHD3 .To used a LC-MS/MS method that built in our laboratory to measure 25OHD, five commercial automated chemiluminescent immunoassays from Abbott Diagnostics ( A ) , DiaSorin LIASON (B), IDS-iSYS(C), Roche Diagnostics(D), and Siemens ADVIA Centaur(E).Taking the reference method LC-MS/MS as a standard , to compared the concordance and performance of the five automated 25OHD immunoassays.And used the commonly accepted cutoffs for 25OHDdeficiency (<20 ng/ml), and insufficiency ( 20 -30 ng/ml ) , and sufficiency (≥30 ng/ml ) to compare the uniformity of different methods .Statistical analysiswere performed by MedCalc software , Passing & Bablok regression , Bland &Altaman plots and Box and whisker plots were performed to compare the differences of the methods .Results The medium ( range:2.5% -97.5%) 25OHD of the 245 serum samples of the six methods was 23.5 (5.8-44.2) ng/ml(LC-MS/MS),20.6 (7.1-43.5)ng/ml(A),19.0 (5.4-38.0) ng/mL (B),23.0 (10.0-38.1) ng/ml(C),20.1 (5.1 -46.0) ng/ml (D),31.3 (12.3 -71.1) ng/ml (E), respectively .Passing and Bablok regression showed that method B had the best correlation coefficient with LC-MS/MS (r=0.894), while methods A, C and D had relatively small bias compared withLC-MS/MS and method E had the large bias .If the serum samples did not contain 25OHD2 , all the five automated immunoassays correlated well with LC-MS/MS with a correlation coefficient higher than 0.84, and B has the best correlation with LC-MS/MS ( r=0.930 ) .While all the correlation coefficient between immunoassays and LC-MS/MS decreasedwhen analyzing the samplescontaining 25OHD2.Using the clinical cutoffs, A, B, C, D and E had a concordance of 68.6%, 64.9%, 67.8%, 70.6% and 51.8% compared with LC-MS/MS, respectively .Conclusions There are significant differences between different detection systems of 25OHD.All the immunoassays results were affected by the existence of 25OHD2 .The concordance of serum 25OHD resultswas poor between different methods , and it may be necessary to built exclusive cutoffs for different methods.

Objective To modify CD47 nanobody with the self-folding peptide human cartilage oligomeric matrix protein (COMP48) so as to enhance its affinity to CD47 antigen. Methods The fusion sequences of COMP48 and CD47 nanobody (VHHB1) were designed and synthesized, and the recombinant plasmid pET22b-VHHB1-COMP48 was constructed and transformed into E. coli BL21 (DE3) to induce expression of the fusion protein. The binding specificity and affinity of the fusion protein and the antigen CD47 were detected by Western Blot, indirect enzyme-linked immunosorbent assay (ELISA) and non-competitive ELISA. Results The recombinant VHHB1-COMP48 was expressed in BL21(DE3) by inducing with 1 mmol/L IPTG and purified at 90％homogenous in IMAC. Western Blot results showed that the recombinant protein VHHB1-COMP48 specifically binds to antigen CD47 but not to unrelated protein. The indirect ELISA and non-competitive ELISA results showed that the affinity of the conjugated recombinant protein VHHB1-COMP48 was enhanced compared to that of the non-conjugated nanobody, and the difference was statistically significant ( P<0 . 01 ) . Through non-competitive ELISA , the constants of affinity and dissociation constants were 6.97 ×107 L/mol and 1.434 ×10-8 mol/L, respectively. Conclusions The affinity of the nanobody for the antigen can be improved by conjugating a human cartilage matrix protein (COMP48) after the nanobody.

Objective To analyze the vitamin D status among apparently healthy younger and elder adults in Beijing based on liquid chromatography tandem mass spectrometry.Methods This is an observational study.Participants included 287 apparently healthy young adults(143 males and 144 females) with an average of (32.2 ± 6.9) years old (19-44 years).At the same time 198 middle-and elder-aged adults were recruited [90 males,108 females,(55.6 ± 7.6) years],and fasting blood samples were collected and serum were isolated.They measured 25-hydroxyvitamin D (25OHD:25OHD2 and 25OHD3)using liquid chromatography tandem mass spectrometry method.Vitamin D with deficiency,insufficiency,sufficiency and intoxication was categorized as 25OHD ＜ 20 ng/ml,20-30 ng/ml,30-150 ng/ml,and ≥ 150 ng/ml,respectively.ALT,Ca,P,Cr,Glu,TG,TC and iPTH wereanalyzed using automatic analyzers.Statistical analysis was performed using SPSS17.0.Results The median 25OHD level in the total studied younger adults was 16.0 [2.5％-97.5％:(6.1-29.0) ng/ml] which didn't show significant difference with that of middle-and elder-aged adults.Younger males had significant higher level of 25OHD than females [17.9 (8.3-32.3) ng/ml vs.14.4 (5.4-26.4) ng/ml,Z =-4.238,P ＜ 0.01].Of the total younger subjects,the rate of vitamin D with deficiency (＜ 20 ng/ml),insufficiency (20-30 ng/ml)and sufficiency (≥30 ng/ml) was 72.8％,25.1％,2.1％,respectively,while that of middle-and elderaged adults was 76.3％,21.2％,2.5％ respectively,and that of younger males was 65.0％,30.8％,4.2％,respectively while that of younger females was 80.6％,19.4％,0％,respectively.Younger females had significantly higher rate of 25OHD deficiency (x2 =31.766,P ＜ 0.01).With adjusting sex,age and BMI,serum iPTH (r =-0.264,P ＜ 0.01) was significantly negatively correlated with 25OHD while Cr (r =0.221,P ＜ 0.01) showed significantly positively correlation with 25OHD.Conclusion Vitamin D deficiency is prevalent in both younger and elder adults in Beijing,especially in younger females.

OBJECTIVETo investigate the changes of aldehyde dehydrogenase 2 (ALDH2) expression in H O inducedcardiomyocytes oxidative stress injury.

METHODSCultured H9C2 cardiomyocytes were exposed to H O -inducedoxidative stress and the effects of the ALDH2 agonist Alda-1 and ALDH2 inhibitor Daidzin were tested on the stress level ofthe exposed cells. MTT colorimetric assay was used to assess the cell viability after the treatments. The oxidative stress level inthe myocardial cells was detected using DHE fluorescence staining, and the activity and protein level of ALDH2 were detectedwith spectrophotometry and Western blotting.

RESULTSCompared with normal control cells, Alda-1 treatment did notsignificantly affect the cell viability, oxidative stress level, or ALDH2 activity and protein level. H O exposure significantlylowered the cell activity and ALDH2 activity and protein expression and increased the oxidative stress level; Alda-1 treatmentobvious antagonized the effects of H O . Blocking ALDH2 with Daidzin produced similar effects to H O exposure on theviability, oxidative stress level, and ALDH2 activity and expression in the myocardial cells.

CONCLUSIONSH O exposure lowersthe activity and reduces the protein expression of ALDH2 in cardiomyocyte H9C2 cells, and activation of ALDH2 can alleviateH O -induced oxidative stress in the cells.

Objective: To investigate the current status and real performance of the detection of RUNX1-RUNX1T1 fusion transcript levels and WT1 transcript levels in China through interlaboratory comparison. Methods: Peking University People’s Hospital (PKUPH) prepared the samples for comparison. That is, the fresh RUNX1-RUNX1T1 positive (+) bone morrow nucleated cells were serially diluted with RUNX1-RUNX1T1 negative (-) nucleated cells from different patients. Totally 23 sets with 14 different samples per set were prepared. TRIzol reagent was added in each tube and thoroughly mixed with cells for homogenization. Each laboratory simultaneously tested RUNX1-RUNX1T1 and WT1 transcript levels of one set of samples by real-time quantitative PCR method. All transcript levels were reported as the percentage of RUNX1-RUNX1T1 or WT1 transcript copies/ABL copies. Spearman correlation coefficient between the reported transcript levels of each participated laboratory and those of PKUPH was calculated. Results: ①RUNX1-RUNX1T1 comparison: 9 samples were (+) and 5 were (-) , the false negative and positive rates of the 20 participated laboratories were 0 (0/180) and 5% (5/100) , respectively. The reported transcript levels of all 9 positive samples were different among laboratories. The median reported transcript levels of 9 positive samples were from 0.060% to 176.7%, which covered 3.5-log. The ratios of each sample’s highest to the lowest reported transcript levels were from 5.5 to 12.3 (one result which obviously deviated from other laboratories’ results was not included) , 85% (17/20) of the laboratories had correlation coefficient ≥0.98. ②WT1 comparison: The median reported transcript levels of all 14 samples were from 0.17% to 67.6%, which covered 2.6-log. The ratios of each sample’s highest to the lowest reported transcript levels were from 5.3-13.7, 62% (13/21) of the laboratories had correlation coefficient ≥0.98. ③ The relative relationship of the reported RUNX1-RUNX1T1 transcript levels between the participants and PKUPH was not always consistent with that of WT1 transcript levels. Both RUNX1-RUNX1T1 and WT1 transcript levels from 2 and 7 laboratories were individually lower than and higher than those of PKUPH, whereas for the rest 11 laboratories, one transcript level was higher than and the other was lower than that of PKUPH. Conclusion The reported RUNX1-RUNX1T1 and WT1 transcript levels were different among laboratories for the same sample. Most of the participated laboratories reported highly consistent result with that of PKUPH. The relationship between laboratories of the different transcript levels may not be the same.