Abstract Background Selective pressure from either the immune response or the use of nucleoside analogs in antiviral therapy could be driving the emergence of HBV mutants. Because of the overlap of the open reading frame (ORF) S for the HBsAg and ORF P for viral polymerase, rtM204I and rtM204V mutations in the polymerase would produce sI195M and sW196S in the HBsAg. The combined effects of immune-escaped mutations (sT118M, sG145K, sG145R) and drug-resistant mutations (rtM204I, rtM204V) on the antigenicity profiles of HBsAg has not been widely explored. Methods To determine the combined effects of immune-escaped and drug-resistant mutants on the antigenicity profiles of HBsAg, recombinant plasmids encoding HBsAg double mutants were constructed using site-directed mutagenesis. The supernatant from each plasmid transfection was analyzed for HBsAg in the western-blotting and five of the most commonly used commercial ELISA kits in China. Results Western-blotting assay showed the successful expression of each HBsAg mutant. All five ELISA kits manifested similar avidity, which were demonstrated by the slope of the curves, for the sT118M mutant, and sT118M-rtM204I (sT118M-sI195M) and sT118M-rtM204V (sT118M-sW196S) double mutants, suggesting that drug-resistant YMDD mutants caused negligible losses in the antigenicity of immune-escaped sT118M HBsAg. In contrast, the presence of the rtM204I (sI195M) mutation, but not rtM204V (sW196S) in combination with the sG145K mutation significantly reduced the avidity of sG145K HBsAg. The rtM204I (sI195M) mutation also decreased the antigenicity profiles for sG145R HBsAg. Conclusions Drug-resistant mutations rtM204I (sI195M) and rtM204V (sW196S) caused significant reduction in antigenicity for the immune-escaped HBsAg mutants sG145K and sG145R, which may hamper HBV diagnosis and disease control from HBV blood-transfusion transmissions in China. The development of ELISA kits with a greater sensitivity for drug-resistant and immune-escaped HBsAg warrants further consideration.
With the increasing demand from aging population and seasonal blood shortage, recruiting and retaining blood donors has become an urgent issue for the blood collection centers in China. This study aims to understand intention to donate again from a social cognitive perspective among whole blood donors in China through investigating the association between the blood donation fear, perceived rewards, self-efficacy, and intention to return. A cross-sectional survey was conducted in six cities, which are geographically and socioeconomically distinct areas in Jiangsu, China. Respondents completed a self-administrated questionnaire interviewed by two well-trained medical students. A total of 191 blood donors were included in the current study. Descriptive analysis, correlation analysis, and a generalized linear regression model were used to explore the association between demographic characteristics, psychological factors, and intention to donate again. After controlling other covariates, donors with higher fear scores reported lower intention to return (p = 0.008). Association between self-efficacy and intention to return was statistically significant (p < 0.001), whereas the association between intrinsic rewards (p = 0.387), extrinsic rewards (p = 0.939), and intention to return were statistically insignificant. This study found that either intrinsic rewards or extrinsic rewards are not significantly associated with intention to donate again among whole blood donors in China, and fear is negatively associated with intention to donate again. Therefore, purposive strategies could be enacted beyond appeals to rewards and focus on the management of donors' fear.
Hepatitis B virus (HBV) is still one of the serious infectious risks for the blood transfusion safety in China. One plausible reason is the emergence of the variants in the major antigenic alpha determinant within the major hydrophilic region (MHR) of hepatitis B surface antigen (HBsAg), which have been assumed to evade the immune surveillance and pose a challenge to the disease diagnosis. It is well documented that some commercial ELISA kits could detect the wild-type but not the mutant viruses. The high prevalence of HBV in China also impaired the application of nucleic acid testing (NAT) in the improvement of blood security. Molecular epidemiological study of HBsAg variations in China is still limited. This study was designed to identify the prevalence of mutations in the HBsAg in voluntary blood donors in Nanjing, China.A total of 20,326 blood units were enrolled in this study, 39 donors were positive for HBV S gene in the nested-PCR. Mutations in the major hydrophilic region (MHR; aa 99-169) were identified by direct sequencing of S region.Among of 20,326 blood units in the Red Cross Transfusion Center of Nanjing from October 2008 to April 2009, 296 samples (1.46%, 296/20,326) were HBsAg positive in the 2 successive rounds of the ELISA test. In these HBsAg positive units, HBV S gene could be successfully amplified from 39 donors (13.18%, 39/296) in the nested-PCR. Sequence analysis revealed that 32 strains (82.1%, 32/39) belong to genotype B, 7 strains (17.9%, 7/39) to genotype C. Besides well known G145R, widely dispersed variations in the MHR of S region, were observed in 20 samples of all the strains sequenced.HBV/B and HBV/C are dominant in Nanjing, China. The mutations in the MHR of HBsAg associated with disease diagnosis are common.
Objective: Astragalus mongholicus could promote angiogenesis.Microemulsion has been widely used in the researches of traditional Chinese medicine in recent years.This study aimed to investigate the effect of Astragalus mongholicus microemulsion modified-collagen on angiogenesis of rats in vivo.Methods: Fifty SD rats were randomly divided into 5 groups: blank collagen,blank microemulsion modified-collagen,vascular endothelial cell growth factor(VEGF) modified-collagen,Astragalus mongholicus microemulsion modified-collagen and Astragalus mongholicus microemulsion plus VEGF modified-collagen.Then four collagen samples were imbedded in each rat.After the establishment of the models,the rats were executed at 3,7 and 14 days.The weights of the collagen samples were measured,and their hematoglobin and hydroxyproline levels were determined by the hemiglobincyanide colorimetric and sampler alkaline hydrolysis methods.The color of the wound surface was observed and the surrounding tissues were examined by HE staining for those killed at 14 days.Results: Both Astragalus mongholicus microemulsion and Astragalus mongholicus microemulsion plus VEGF significantly increased the production of hematoglobin and hydroxyproline(P0.05,P0.01),as well as the number of micrangia.However,there were no significant differences between the groups of Astragalus mongholicus microemulsion modified-collagen and VEGF modified-collagen(P0.05).Conclusion: Astragalus mongholicus microemulsion might promote angiogenesis by increasing the number of micrangia and the production of hematoglobin and hydroxyproline.
A four tracks robot with double rocker arms and differential mechanism is developed. The body of the robot is driven by a single DC motor, and realizes the forward, backward and steering actions by matching with the electromagnetic brakes, and the output power from differential half shafts can be allocated to the double rocker arms, so as to complete the obstacle action. Meanwhile, the obstacle-surmounting performance of step-climbing is analyzed, by establishing the relationship of the inclination angle of the robot, the elevation angle of the swing arm and the height of the step-climbing, the theoretical value of the maximum obstacle height is obtained. And based on the test of the prototype, the measured value of the obstacle height is compared with the theoretical value.
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