Objective:To develop a national secondary reference material of Urea and Creatinine in frozen human serum as a standard for metrological traceability.Methods:According to JJF1343-2012 "General and Statistical Principles for Characterization of Reference Materials" and JJF 1006-1994 " Technical Norm of Primary Reference Material ", the homogeneity, stability, and commutability were evaluated;Using the JCTLM recommended methods, the value of the reference materials was assigned through collaboration with 6 accredited reference laboratories from Guangdong Provincial Hospital of Chinese Medicine, Beijing Aerospace General Hospital, Shenzhen Mindray Bio-Medical Electronics, Maccura Biotechnology, Beijing Leadman Biochemistry, and Zhejiang MedicalSystem Biotechnology. Uncertainty components including inhomogeneity, stability and value assignment were evaluated.Results:The results of one-way analysis of variance of homogeneity for the reference materials showed P>0.05, and the stability evaluation was less than the critical value of the t-test. The measured values were in the 95% confidence interval in the four conventional detection systems for commutability, and the certified values and expanded uncertainties were urea:(14.7±0.3) mmol/L ( k=2),Cr:(313.9±14.5) μmol/L ( k=2). Conclusion:The prepared secondary reference materials of urea and creatinine had promising homogeneity, stability, and commutable, the values of urea and creatinine concentration in reference materials were accurate and reliable.

The concentration and accumulation rate of advanced glycation end products (AGEs) in the body are highly correlated with glycometabolic disorders. Therefore, the clinical detection of AGEs is of great value for the early diagnosis and prognostic evaluation of these diseases. However, due to the complexity of its structure, the diversity of glycosylation sites, and the limitations of existing detection methods, there is still a lack of widely available detection methods in clinical practice. Starting from the structure and classification of AGEs and the value of clinical testing, this article summarizes current status of various laboratory detection methods of AGEs, and the deficiencies and challenges of these testing methods, future directions are further prospected.

Objective:To establish a candidate reference method for serum progesterone using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) in our laboratory, validate the analytic performance of five clinical routine detection systems to explore the comparability of serum progesterone detection by different detection systems.Methods:A candidate reference method for serum progesterone using ID-LC/MS/MS method was established. The sample was pretreated by liquid-liquid extraction method, and the reversed phase liquid phase separation in positive ion mass spectrometry mode was used to detect progesterone in human serum, and the detection time of a single sample was controlled within 5 minutes by gradient elution. In order to improve the accuracy of the method, the bracketing calibration method (BCM) was used to establish the standard curve. The sensitivity, accuracy, precision and specificity of BCM and classical calibration curve method were evaluated according to CLSI C62-A, EP15-A2, EP6-A2 and EP9-A3, and the analytical performance and comparability of five clinical routine progesterone detection systems were evaluated,compared with ID-LC/MS/MS method, the bias at medical decision level 2 and 25 ng/ml was evaluated to see if they were <1/2TEa (12.5%).Results:The limit of detection (LOD) of ID-LC/MS/MS was 0.005 ng/ml. The recoveries of BCM method and classical calibration curve method are 97.95%-101.58% and 96.88%-110.70%, respectively. The measurement results of BCM method for certified reference materials are within its declared uncertainty range. The intra-and inter-assay coefficient of variation ( CV) of BCM method was less than 3.0%, which was better than that of classical calibration curve method ( CV: 2.48%-9.33%). The precision and linear range of the five clinical routine detection systems can meet the detection requirements. The measurement bias of detection system 1, 3 and 5 at 25 ng/ml of medical decision level was less than 1/2TEa, and the measurement bias at 2 ng/ml of medical decision level was more than 1/2TEa. The measurement bias of detection system 2 and 4 at two medical decision levels was less than 1/2TEa. Conclusion:The candidate reference method for serum progesterone ID-LC/MS/MS established in our laboratory meets the requirements of the reference method. BCM has better detection performance than classical calibration curve method. The precision and linearity of the five progesterone clinical detection systems are satisfactory. The five clinical detection systems could meet the clinical requirements at the medical determination level of 25 ng/ml, however, only two of the five clinical detection systems meet the clinical requirements at the medical determination level of 2 ng/ml.

Objective:To investigate the prognostic factors of Siewert type Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction (AEG) after radical resection with different surgical approaches.Methods:The retrospective case-control study was conducted. The clinicopathological data of 442 patients who were admitted to Tianjin Medical University Cancer Institute and Hospital from February 2003 to July 2011 were collected. There were 362 males and 80 females, aged from 21 to 85 years, with a median age of 64 years. Patients underwent radical resection of AEG. Observation indicators: (1) surgical situations; (2) follow-up; (3) progrostic factors analysis of AEG after radical resection; (4) survival of patients after radical resection of AEG via abdominal approach; (5) survival of patients after radical resection of AEG via thoracoabdominal approach; (6) survival of patients after radical resection of Siewert type Ⅱ type AEG; (7) survival of patients after radical resection of Siewert type Ⅲ AEG. Follow-up using outpatient examination and telephone interview was performed to detect postoperative survival of patients up to June 2018. Measurement data with skewed distribution were described as M (range). Count data were expressed as absolute numbers or percentages. Kaplan-Meier method was used to calculate survival rates and draw survival curves, and Log-rank test was used for survival analysis. Univariate analysis was conducted using the Kaplan-Meier method. Multivariate analysis was conducted using the COX proportional hazard model. Results:(1) Surgical situations: 442 patients underwent radical resection of AEG, including 204 via abdominal approach and 238 via thoracoabdominal approach. There were 391 patients with D 2 lymphadenectomy and 51 with D 2+ lymphadenectomy. (2) Follow-up: 442 patients were followed up for 8-162 months, with a median follow-up time of 37 months. All the 442 patients survived for 2-156 months, with a median survival time of 31 months. The 1-, 3-, 5-year overall survival rates were 79.2%, 42.0%, 30.0%, respectively. (3) Prognostic factors analysis of AEG after radical resection: results of univariate analysis showed that tumor diameter, Lauren type, pathological T staging, pathological N staging, pathological TNM staging, lymphatic vessel invasion, and soft tissue infiltration were related factors for prognosis of patients after radical resection of Siewert type Ⅱ and Ⅲ AEG ( χ2=4.028, 4.885, 19.435, 17.014, 34.449, 9.707, 11.866, P<0.05). Results of multivariate analysis showed that pathological TNM staging, lymphatic vessel invasion, and soft tissue infiltration were independent influencing fators for prognosis of patients after radical resection of Siewert type Ⅱ and Ⅲ AEG ( hazard ratio=1.255, 0.486, 1.454, 95% confidence interval: 1.024-1.539, 0.325-0.728, 1.096-1.928, P<0.05). (4) Survival of patients after radical resection of AEG via abdominal approach: of the 204 patients undergoing radical resection of AEG via abdominal approach, the 1-, 3-, 5-year survival rates were 83.6%, 50.4%, 37.8% for 121 patients with Siewert type Ⅱ AEG, respectively, versus 72.0%, 39.3%, 31.8% for 83 patients with Siewert type Ⅲ AEG, showing no significant difference in the survival between the two groups ( χ2=1.854, P>0.05). (5) Survival of patients after radical resection of AEG via thoracoabdominal approach: of the 238 patients undergoing radical resection of AEG via thoracoabdominal approach, the 1-, 3-, 5-year survival rates were 79.6%, 38.8%, 23.8% for 183 patients with Siewert type Ⅱ AEG, respectively, versus 79.1%, 37.6%, 29.3% for 55 patients with Siewert type Ⅲ AEG, showing no significant difference in the survival between the two groups ( χ2=0.215, P>0.05). (6) Survival of patients after radical resection of Siewert type Ⅱ AEG: of the 304 patients with Siewert typeⅡAEG, the postoperative 1-, 3-, 5-year survival rates were 83.6%, 50.4%, 37.8% for 121 patients undergoing radical resection of AEG via abdominal approach, respectively, versus 79.6%, 38.8%, 23.8% for 183 patients undergoing radical resection of AEG via thoracoabdominal approach, showing no significant difference in the survival between the two groups ( χ2=2.406, P>0.05). (7) Survival of patients after radical resection of Siewert type Ⅲ AEG: of the 138 patients with Siewert type Ⅲ AEG, the postoperative 1-, 3-, 5-year survival rates were 72.0%, 39.3%, 31.8% for 83 patients undergoing radical resection of AEG via abdominal approach, respectively, versus 79.1%, 37.6%, 29.3% for 55 patients undergoing radical resection of AEG via thoracoabdominal approach, showing no significant difference in the survival between the two groups ( χ2=0.640, P>0.05). Conclusions:Pathological TNM staging, lymphatic vessel invasion, and soft tissue infiltration are independent fators for prognosis of patients after radical resection of Siewert type Ⅱ and Ⅲ AEG. Siewert types and surgical approach are not related factors for prognosis of patients after radical resection of AEG. There is no significant difference in the survival between patients with different Siewert types of AEG undergoing radical resection via different surgical approaches.

The performance of high sensitivity, specificity and throughput makes liquid chromatography-tandem mass spectrometry (LC-MS/MS) quickly developed and well applicated in clinical laboratories, such as quantitative detection of steroids, vitamins and metabolic small molecules, monitoring drug concertrations as well as the establishing reference methods or verifying reference materials. However, there were still some challenges for the widespread clinical application of LC-MS/MS.

Objective To express adenosine deaminase protein by molecular cloning technique.MethodsTotal RNA was extracted from human leukocytes and the cDNA was obtained by reverse transcription.Whereupon the cDNA was used as a template to amplify adenosine deaminase gene by polymerase chain reaction (PCR) and then integrated it into three prokaryotic plasmids pET-28 b, pET-32 a (+) and pHSIE.The plasmid with the correct sequencing was transformed into E.coli BL21 (DE3) by CaCl2 method for the protein expression.The expression activity of these fusion proteins were detected by Western-blot and SDS-PAGE, with the optimized expression conditions.Results Complete fusion of target gene and three prokaryotic plasmids was observed through sequencing.The expressed and accurate ADA protein was identified by Westernblot and SDS-PAGE.The optimal expression conditions were observed:the protein expression would be induced with 0.4 mmol/L IPTG and incubated at 16℃for 24 hours.Conclusion The prokaryotic vectors of adenosine deaminase (BL21+pET-28 b+ADA, BL21+pET-32 a+ADA, BL21+pHSIE+ADA) were successfully constructed and efficiently expressed.

There are many types of serum tumor markers,and their structures and functions vary.The standardization and harmonization of serum tumor markers will contribute to clinical diagnosis and treatment.Therefore,many scholars are committed to the research of their standardization.However,there are only a few items have been standardized.Due to the complexity of determination,most tumor markers are still facing problems and challenges in the process of achieving standardization.

Renal function test items mainly include creatinine, urea, uric acid, cystatin C, urine-alb, urine protein, α1-microglobulin, β2-macroglobulin and retinol binding protein, etc.The standardization and harmonization of these renal function test items will contribute to clinical diagnosis and treatment.Therefore, many scholars are committed to the standardization of renal function tests and part of these testshave been standardized.But some test items, due to the complexity of the determination, the process of achieving standardization are still facing some problems and challenges.

Objective To discuss the feasibility of enzymatic reference methods in Routine Chemistry external quality assessment (EQA)inlaboratorymedicine.Methods Samplesofthe1stEQAin2012byNationalCenterforClinicalLaboratories(NCCL)and patients′sera were measured by reference methods and 5 clinical analytic systems for the catalytic activity of CK ,LDH ,ALP ,ALT , AST ,GGT and AMY ,then the results of 5 clinical systems were compared with the reference methods′or target value of NCCL by calculating the bias ,and evaluated them according to the criteria of EQA by NCCL .Results The results of EQA samples measured by reference methods was within ± 10% compared with NCCL target value .Compared with the results of reference method ,the through put was 100 .0% for wet clinical chemistry systems measuring both EQA samples and patients′serum ,and the dry clinical chemistry systems was 77 .1 for EQA samples and 97 .1% for patients′serum according to the criterion of EQA ,and the through put was 72 .9% and 63 .6% of wet clinical chemistry systems according to the standard of enzymatic trueness of NCCL .Conclusion Reference method could be applied to EQA ,and will be a great help for the trueness of clinical testing .

Objective To construct the recombinant plasmid pET32a-AKT1 and express human AKT1 protein using prokaryotic expression system .Methods Reverse transcriptase-polymerase chain reaction(RT-PCR) was employed to amplify the gene AKT1 in coding region and integrated it with pET 32a plasmid ,following by transforming it into Escherichia coli DH5α and prokaryotic strains BL21(DE3) .Isopropyl-beta-D-thiogalactopyranoside(IPTG) was adopted to induce its expression .Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE ) and Western-blot were used for protein identification .Results Complete fusion of target gene and plasmid was observed .The recombinant plasmid pET32a-AKT1 was successfully transferred into the strain DE3 . After IPTG induction ,protein with relative molecular mass 70 000 was expressed by DE3 .Conclusion The recombinant plasmid pET32a-AKT1 is constructed successfully and AKT 1 protein is completely and efficiently expressed by prokaryotic strain DE 3 .