High-level soluble expression of human Cu,Zn superoxide dismutase with high activity in Escherichia coli.

As the most important member of antioxidant defense system, human Cu,Zn superoxide dismutase (hCu,Zn-SOD) protects cells against the free radicals produced by aerobic metabolism. hCu,Zn-SOD has been widely used in food, cosmetic and medicine industry due to its health benefits and therapeutic potentials. However, a more extensive application of hCu,Zn-SOD is limited by the challenge of expensive and low production of high-activity hCu,Zn-SOD in large scale. In this study, the codon-optimized hCu,Zn-SOD gene was synthesized, cloned into pET-28a( +) and transformed into Escherichia coli BL21(DE3). After induction with IPTG or lactose, hCu,Zn-SOD was highly expressed as soluble form in LB medium with 800 µM Cu2+ and 20 µM Zn2+ at 25 °C. The recombinant hCu,Zn-SOD was efficiently purified by nickel affinity chromatography. Through optimization of fed-batch fermentation conditions, 342 mg purified hCu,Zn-SOD was obtained from 1 L cultures fermented in a 3-L bioreactor. Furthermore, the recombinant hCu,Zn-SOD retained the enzymatic specific activity of 46,541 U/mg. This study has opened up an effective avenue for industrial production of hCu,Zn-SOD through microbial fermentation in the future.

The association between mean platelet volume and chronic atrial fibrillation and the presence of thrombotic events.

Mean platelet volume (MPV), a marker of platelet activation, is a surrogate marker of platelet function and a potential mediator of the association between inflammation and thrombosis. The present retrospective study sought to investigate the association between MPV and the presence of thrombotic events (TEs) in patients with chronic atrial fibrillation (AF). A total of 114 consecutive patients with chronic AF were enrolled from a Chinese hospital. Individuals were divided into three groups: The AF+TE group (n=57, 33.1%), which comprised patients in AF with concomitant TEs; the AF group (n=57, 33.1%), which comprised patients in AF with no identifiable TEs, as confirmed by brain computed tomography, transesophageal echocardiography, or a combination of the two; and a control group (n=58, 33.7%), which consisted of patients who were in sinus rhythm. MPV, high-sensitivity C-reactive protein (hsCRP), D-dimer and the left atrial diameter (LAD) were analyzed in the 172 participants. The MPV level of patients in the AF+TE group was significantly higher than that of patients in the AF and control groups (P<0.05). In the correlation analysis, MPV levels were found to be positively correlated with LAD, D-dimer concentrations and hsCRP levels in patients with AF (r=0.960, P<0.05; r=0.896, P<0.05; and r=0.924, P<0.01, respectively). In the receiver operating characteristic curve analysis, the value for MPV levels required to detect TEs with a sensitivity of 77.5% and specificity of 78% was 10.5 femtoliter (fl). A high MPV level (>10.5 fl) was significantly associated with the occurrence of TEs (odds ratio, 3:1; 95% confidence interval, 1.6-5.1; P=0.000). The results of the present study suggest that an additional biomarker, MPV, has a predictive value for the presence of TEs in patients with AF. MPV may be a potential mediator between inflammation and thrombosis.

The effects of catheter-based radiofrequency renal denervation on renal function and renal artery structure in patients with resistant hypertension.

There are no clinical studies on the effects of catheter-based radiofrequency renal denervation (RDN) on renal artery structure using 64-detector computed tomography (CT). A total of 39 patients with resistant hypertension received RDN and 38 patients received drug treatment. Mean systolic pressure and diastolic pressure in the RDN group decreased after 1, 3, 6, and 12 months of procedure (P<.05) and urinary protein level significantly decreased after 6 and 12 months (P<.05). The diameter, length, and sectional area of the renal artery; number of cases of atherosclerosis; and plaque burden of 64-detector CT renal arteriography did not change at 12 months of follow-up (P<.05), whereas the plaque burden increased significantly in the control group (P<.05). RDN significantly and persistently reduced blood pressure and decreased urinary protein excretion rate in patients with resistant hypertension and did not exhibit any adverse effect on renal function and renal artery structure.

Genetic characterization and serological prevalence of swine hepatitis E virus in Shandong province, China.

Hepatitis E virus (HEV), the causative agent of hepatitis E, is classified into four major genotypes (1 to 4) and swine is the main natural reservoir for genotypes 3 and 4. In this study, a total of 106 bile samples from a slaughterhouse in the Shandong province of China were tested for the partial ORF2 gene of HEV by RT-nPCR to determine the virus genotypes, and two indirect ELISA were developed for the detection of swine HEV specific IgM and IgG antibodies in 980 serum samples from 24 farms, in order to investigate the seroprevalence. Thirty-two out of 106 (30.2%) bile samples were positive for HEV and a high degree of partial ORF2 sequence similarity (86.8-100%) was observed among 20 samples. The viral sequences belonged to genotype 4, subtypes 4a and 4d. One complete genome sequence of a subtype 4d HEV was further determined and characterized. The seroprevalence of HEV IgG and IgM antibodies was 100% (24/24) and 41.7% (10/24) for herds, and 66.4% (651/980) and 1.6% (16/980) for the individual pigs, respectively. These results suggested a high prevalence of genotype 4 of swine HEV infection both in swine farms and at the slaughterhouse in Shandong province, which further raise public-health concerns for zoonosis and pork safety.