3-Deoxy-D-manno-octulosonate 8-phosphate synthase (KDO8PS) is the key enzyme to synthesize eight-carbon sugar in plant and gram-negative bacterial cell wall. To analyze the polymerization and characterization in plant KDO8PS, the candidate gene was cloned from fresh Phyllostachys edulis seedling by RT-PCR. The open reading frame of PeKDO8PS is 876 bp deduced into 291 amino acid residues. The target protein was overexpressed in Escherichia coli induced by IPTG and then lager amount of fusion protein was purified through two-step methods with affinity chromatography and size-exclusion chromatography (SEC). SEC analysis shows that PeKDO8PS protein existed mainly in the form of dime in solution. Glutaraldehyde cross-linking experiments confirmed that the enzyme could form dimers. Further we identified that KDO8PS at high concentration two dimers could form tetramer in aqueous solution by analytical ultracentrifuge (AUC) analysis. The pH of the catalytic reaction was between 4.0 and 9.0, the optimum pH value was 8, the thermal stability range was between 25 and 65 ℃, and the optimum temperature was about 55 ℃. The enzyme activity was inhibited by some metal ions at lower concentrations, especially in the presence of Fe3+metal ion and activated by metal protease inhibitor EDTA at low concentration.

Objective To describe the distribution of medication costs of rheumatoid arthritis patients, and to analyze the factors that may affect the costs. Methods Data were obtained from a 12-month retrospective investigation of patients with rheumatoid arthritis (RA) across China. Department of Rheuma-tology of 18 hospitals were randomly selected. The data about their social conditions, clinical conditions, medications associated with RA such as disease-modifying antirheumatic drugs (DMARDs), non -steroidal anti -inflammtory drugs (NSAIDs), steroids, biologic agents were collected, and the costs of drugs were calculated. A non-parameter test and multivariate logistic regression analysis were performed. Results Six hundred and forty six patients were enrolled into the study, 435 completed data were chosen for analysis. The results demonstrated that the average costs per patient for medications in the past year was 8018 . The total medication costs were further subdivided into the following parts: DMARDs, (represented 20% of the total costs), biologic drugs (49%), NSAIDs (4%), herbal drugs (22%), steroids (1%). Data analysis showed that patients with higher education and higher incomes, with medical insurance,better health function status and outpatients paid more on DMARDs. Extra-articular manifestations increased the odds of the high-cost group (OR: 2.180, 95%CI: 1.335～3.558, P=0.002), while poor health function status increased the probability of paying high costs (OR: 1.373, 95%CI: 1.012～1.863, P=0.041). Conclusion High medication costs in RA do exist in RA patients. The costs of medication is associated with health function status and the presence of extra-articular manifestations.

ObjectiveTo examine the clinical features of fractures and related risk factors in patients with rheumatoid arthritis(RA) in China.MethodsSix hundred and eighty-one RA patients were randomly selected from department of rheumatology of 18 hospitals of China.Data were obtained from the questionnaire,including age,sex,disease duration,the involvement of joints,treatment regimen,features of fractures etc.The possible risk factors of fracture in patients with RA were analyzed with a multi-variate Logistic regression analysis.Results① In 681 RA patients of the survey,48 patients had 54 fractures,and the incidence of fractures was about 8％.② Fractures occurred at various sites.Foot/ankle,femur,spine and wrist were the mostfrequent sites.③ The Logistic regression analysis showed that several factors increased the risk of fracture in RA patients,including long disease duration (OR:1.245,95％CI:0.987-1.570,P=0.065),male gender(OR:0.433,95％CI:0.199-0.942,P=0.035),more deformed joints(OR:1.042,95％CI:1.006-1.079,P=0.023),family history of RA (OR:2.201,95％CI:0.984-4.923,P=0.055),and high scores of SF-36(OR:1.017,95％CI:1.002-1.033,P=0.028).④ According to the degree of correlation from strong to weak,the risk factors of fracture were disease duration,SF-36,sex,number of deformed joints and family history of rheumatoid arthritis.ConclusionThe incidence of fracture is high in patients with rheumatoid arthritis.Several factors could increase the risk of fractures in RA patients,including long disease duration,male gender,more deformed joints,and family history of RA.In order to prevent the occurrence of fractures,cautions should be taken to prevent the development of fractures and treat the disease aggressively to suppress the disease activity of RA.