AIM: To explore the expressive role of lipoprotein-associated phospholipase A_2, high sensitive C-reactive protein and matrix metalloproteinase-9 in vulnerable atherosclerotic plaques in a rabbit model. METHODS: Forty eight New Zealand white male rabbits were randomly divided into 4 groups (12 rabbits each): control group, stable plaque group, p53 group, and p53+drug group. Rabbits in control group were fed with a regular diet and underwent sham operation. Rabbits in stable plaque group, p53 group and p53+drug group underwent balloon induced arterial wall injury and then were fed on a diet with 1% cholesterol. The animals were all fed for 3 months, then the rabbits in p53 group and p53+drug group underwent Ad5-CMV p53 transfection at 10th week. Before killed, the animals in p53+drug group underwent pharmacological triggering with Russell's viper venom (RVV) and histamine to induce the rupture of the atherosclerotic plaques. At the 1st day and before sacrifice, the serum was collected for measuring Lp-PLA_2, hs-CRP, MMP-9, HDL, LDL and VLDL. The expressions of Lp-PLA_2, hs-CRP and MMP-9 in tissues were determined by the methods of hybridization and immunohistochemistry. RESULTS: At the end of 12th week, the serum and tissue levels of Lp-PLA_2 and MMP-9 in stable plaque group, p53 group and p53+drug group were significant different from those in control group and in each group at the first day (P<0.05). The serum levels of Lp-PLA_2 and hs-CRP in p53 group and p53+drug group were significantly higher than those in control group and stable group (P<0.05). The serum levels of Lp-PLA_2, hs-CRP and MMP-9 were all significantly different between p53 group and p53+drug group (P<0.05). At the end of 12th week, pathological results showed that 4 groups were normal artery, stable plaque, vulnerable plaque and rupture plaque, respectively. The fabric cap was thicker in plaque groups than that in normal group (P<0.05). The rupture and formation of thrombus were more significant in p53+drug group than those in p53 group. The serum level of Lp-PLA_2 had negative interrelated relationship with fabric cap in plaque groups (r=-0.710, P<0.01), and hs-CRP, MMP-9 had no interrelated relationships with fabric cap in plaque groups. CONCLUSION: Base on the successful establishment of the atherosclerotic plaque animal model, serum Lp-PLA_2 shows better interrelated relationships to plaques stability. Combination with hs-CRP and MMP-9, we can exactly evaluate the nature of plaques.

Objective To study the sequence structure of Salmonella typhimurium Ssek3 gene and to express it at protein level in a prokaryotic expression system .Methods Sequence of Ssek3 gene was ob-tained from Salmonella typhimurium SL1344 strain.Bioinformatics methods were used for systematic analy-sis .A prokaryotic expression system for expressing Sse3k gene was constructed and the expressed protein was purified by Ni-NTA affinity chromatography .Results Sequence analysis showed that the Ssek3 gene of Sal-monella typhimurium was 1008 bp in length, encoding a protein of 335 amino acids and 72 amino acid resi-dues.The molecular weight, molecular formula and isoelectric point of Ssek3 protein was 37.89×103, C1700 H2629 N463 O497 S12 and 6.7, which indicated that it was a stable and hydrophilic protein .Ssek3 protein was a membrane protein without signal peptide or transmembrane region , containing five N-glycosylation sites , three O-glycosylation sites , 33 phosphorylation sites , 22 linear B-cell epitopes , 11 T-cell epitopes and 21 di-sulfide bonds.The secondary structure of Ssek3 protein contained 114 α-helices (Hh) (34.03％), 72 ex-tended chain (Ee) (21.49％), 30β-sheets (Tt) (8.96％) and 119 random coils (Cc) (35.52％).Re-sults of SDS-PAGE showed that the fusion protein Ssek 3 expressed in the prokaryotic expression system was a secretory protein with a molecular weight of about 40×103 .Conclusion The Ssek3 gene of Salmonella typh-imurium is successfully cloned , sequenced and expressed in this study , which will lay a foundation for fur-ther studying the role of Ssek3 protein in host cells during Salmonella typhimurium infection.

Objective:To establish autoverification rules for coagulation tests in multicenter cooperative units, in order to reduce workload for manual review of suspected results and shorten turnaround time (TAT) of test reports, while ensure the accuracy of results.Methods:A total of 14 394 blood samples were collected from fourteen hospitals during December 2019 to March 2020. These samples included: Rules Establishment Group 11 230 cases, including 1 182 cases for Delta check rules; Rules Validation Group 3 164 cases, including 487cases for Delta check; Clinical Application Trial Group 77 269 cases. Samples were analyzed for coagulation tests using Sysmex CS series automatic coagulation analyzers, and the clinical information, instrument parameters, test results, clinical diagnosis, medication history of anticoagulant and other relative results such as HCT, TG, TBIL, DBIL were summarized; on the basis of historical data, the 2.5 and 97.5 percentile of all data arranged from low to high were initially accumulated; on the basis of clinical suggestions, critical values and specific drug use as well as relative guidelines, autoverification rules and limits were established.The rules were then input into middleware, in which Stage I/Stage II validation was done. Positive coincidence, negative coincidence, false negative, false positive, autoverification pass rate, passing accuracy (coincidence of autoverification and manual verification) were calculated. Autoverification rules underwent trial application in coagulation results reports.Results:(1) The autoverification algorisms involve 33 rules regarding PT/INR, APTT, FBG, D-dimer, FDP,Delta check, reaction curve and sample abnormalities; (2)Autoverification Establishment Group showed autoverification pass rate was 68.42% (7 684/11 230), the false negative rate was 0%(0/11230), coincidence of autoverification and manual verification was 98.51%(11 063/11 230), in which positive coincidence and negative coincidence were respectively 30.09% (3 379/11 230) and 68.42%(7 684/11 230); Autoverification Validation Group showed autoverification pass rate was 60.37%(1 910/3 164), the false negative rate was 0%(0/11 230), coincidence of autoverification and manual verification was 97.79%(3 094/3 164), in which positive coincidence and negative coincidence were respectively 37.42%(1 184/3 164) and 60.37%(1 910/3 164); (3) Trialed implementation of these autoverification rules on 77 269 coagulation samples showed that the average TAT shortened by 8.5 min-83.1 min.Conclusions:This study established 33 autoverification rules in coagulation tests. Validation showedthese rules could ensure test quality while shortening TAT and lighten manual workload.