BACKGROUND: Magnitude and action ways of flow shear stress are important for the endothelialization of small diameter tissue-engineered vessels (TEV), and the TEV resistance ability to blood flow even decides the destiny of implantation. There are many studies on how to construct the TEV and improve anticoagulant ability of TEV after host cell implantation, but the effects of different flow shear stresses on the TEV endothelialization is rarely reported, which may be helpful for increasing the success rate of TEV implantation. OBJECTIVE: To compare the effects of flow shear stresses in single level or stepwise increased on the endothelialization of small diameter TEV and to optimize the TEV in the aspects of shear stress magnitude and loading method. METHODS: The number, morphology and adhesion ability of endothelial cells on the inner wall of TEV were observed through silver nitrate and F-actin staining. RESULTS AND CONCLUSION: Single-level shear stress at 2.5, 3.0 N/m2 for 2 hours removed almost all the endothelial cells seeded on the inner wall of TEV. In contrast, stepwise increased shear stress from 0.5 N/m2 to 3.0 N/m2 at an increase of 0.2 N/m2/2 hours maintained the integrity and oriented along the flow direction, and could induce stress fibers productionin endothelial cells. These results suggest that the stepwise increased flow shear stress can improve the endothelialization of TEV.

Objective To evaluate the quality of four domestic and three imported fourth-generation HIV diagnostic reagents.Methods The specificity and sensitivity of these assays were analyzed when testing HIV negative samples and HIV-1 RNA positive samples.The relative seroconversion sensitivity index was analyzed when testing BBI seroconversion panels.Results The sensitivity of seven 4th-generation assays were 100％ (95％ CI:99.86％-100％ ),and one sample at the window period of HIV-1 infection were detected as positive.Of the seven assays,one imported assay exhibited the relative largeδ + value (1.0892),and the small δ+ value were found on the remaining six assays (0.0836-0.3003 ).For the samples negative for HIV antibody,varying degrees of false positives were observed on the seven assays ( specificity:97.80％ -99.60％,δ- value:-1.3803 to -0.4778).When testing the BBI seroconversion panels,the relative seroconversion sensitivity index of domestic assays were -0.500-0,however,which of imported assays were -0.600 and -0.700.Conclusion The seven reagents exhibited high sensitivity and specificity.The 4th generation HIV assays can be used as blood screening reagents to find the samples at window period of HIV-1 infection,thus indicating the certain meaning in reducing the transmission risk of HIV-1 for fourth-generation HIV diagnostic reagents.However,the better efficiency to detect HIV-1 early infection was observed on the imported assays than on the domestic assays.

Objective To evaluate the differences between the third and the fourth generations of anti-HIV assays,and different kits within the same generation.Methods A total of 989 HIV-negative samples,185 samples positive for HIV-1 RNA.1st-generation international references of HIV antibodies and samples from 9 sets of BBI seroconversion panels were detected by 8 kits of the third generation and 4 kits of the fourth.Results The fourth generation kits can detect HIV infection earlier than the third generation kits.However,the detected days of HIV infection with different kits of the fourth generation were different whilst no significant difierences were found with difierent kits of the third generation.Furthermore,the capacity of detecting samples with different genotypes for different reagents was different,especially the capacity of domestic reagents on detecting HIV-1 O group and HIV-2 samples was relatively weak.Conclusion These data provided information to improve the quality of anti-HIV diagnostic reagents further.

Objective To investigate the feasibility of low-tube-voltage in combination with the three-dimensional adaptive iterative dose reduction (AIDR-3D) algorithm in performing lower extremity computed tomography angiography (CTA).Methods A total of 60 patients suspicious of lower extremity arterial occlusion were randomized into control group (120 kV,a =30) and experimental group (100 kV,n =30).The CTA was undertaken with a 320-row scanner (Toshiba Aquilion ONE),and the images was reconstructed with filtered back projection (FBP) algorithm in control group and FBP as well as the AIDR-3D algorithm in experimental group.The subjective image quality,vascular density (VD),noise,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),and dose length product (DLP) were compared between two groups.Results The DLP was significantly lower in experimental group than that in control group [(503.5± 104.7) vs.(1 099.4 ± 151.7) mGy·cm,t =15.7,P ＜0.05].The images in experimental group with 100 kV and FBP protocol had significantly increased VD and noise (t =-3.13,-3.61,P ＜ 0.05) than that in the control.The images in experimental group with AIDR-3D had significantly lower noise and higher SNR and CNR than that with FBP (t =13.59,2.14,P ＜ 0.05),also significantly lower noise and significantly higher VD,SNR,and CNR than that in the control (t =-3.75,-4.19,-4.15,P ＜ 0.05).Conclusions Low-tube-voltage (100 kV) combined with AIDR-3D reconstruction could significantly improve the image quality and reduce radiation dose in lower extremity CTA with a 320-row CT scanner.Trial registration Chinese clinical trial registry,ChiCTR-DPD-16008054.

Objective To establish HIV-1 seroconversion panels with the samples collected by National Institutes for Food and Drug Control ( NIFDC) and to evaluate the window periods of HIV enzyme immunoassay ( EIA) diagnostic kits used for blood screening with them. Methods Serum specimens were collected from different plasma donation stations in China. All suspected HIV infection specimens were screened for HIV by using the nucleic acid amplification testing (NAT), Western blot confirmatory assay and P24 quantitative detection assay. The HIV env gene sequences were amplified by RT-PCR for further confirmation of HIV infection. The PCR products were sequenced and genotyped. The confirmed seroconver-sion panels were used to evaluate the early detection capabilities of the 4th and 3rd generation HIV EIA diag-nostic kits used in blood screening in china. Results A total of 8 sets of HIV seroconversion panels com-prised of 36 samples were confirmed in this study, including 6 sets of AE subtype, 1 set of B subtype and 1 set of unknown genotype. Those seroconversion panels were tested with HIV diagnostic kits produced by 19 different manufacturers. For the early detection of HIV infection, the 4th generation HIV diagnostic kits with a score of 9. 4 points were better than the 3rd generation HIV diagnostic kits whose score was 3. 6 points (P<0. 01, t=8. 547). Some of the domestic 4th generation HIV diagnostic kits were similar to the imported kits in the early detection of HIV infection. In terms of the diagnosis of HIV infection, the HIV-1 NAT was at least 2 weeks earlier than the HIV EIA diagnostic kits. The sensitivity of confirmatory assay was lower than that of the diagnostic kits. Four out of five 4th generation HIV diagnostic kits showed declined signal to cut off ( S/CO ) ratio , indicating the probability of false detection during the second window period . Conclusion Eight sets of NIFDC HIV-1 seroconversion panels were established in this study. With those panels we found that there were differences in the window period between different EIA diagnostic kits used for HIV blood screening.

Objective: To investigate the prevalence of dyslipidemia among adult professional athletes in Guangdong Province, so as to provide insights into dyslipidemia screening and health management among professional athletes. Methods: In 2019, active athletes at ages of 18 to 30 years were recruited from 12 provincial sports teams in Guangdong Province using a cluster sampling method. A self-designed questionnaire survey was conducted to collect gender, age and sport items, and the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were detected. The non-HDL-C level was calculated, and the gender- and sport item-specific prevalence of dyslipidemia was estimated. Results: Totally 460 athletes were investigated, including 245 males (53.26%) and 215 females (46.74%), with a mean age of (21.91±2.77) years. The overall detection of dyslipidemia was 25.87%, and the detection rates of high TG, high TC, high LDL-C, low-HDL-C and high non-HDL-C were 20.22%, 5.87%, 13.04%, 3.26% and 9.57%, respectively. The detection rates of high TG (9.39% vs. 1.86%; χ2=11.743, P<0.05), low HDL-C (5.31% vs. 0.93%; χ2=6.951, P<0.05) and high non-HDL-C (12.24% vs. 6.51%; χ2=4.351, P<0.05) were significantly greater in men than in women, and the detection of high TC was lower in men than in women (17.96% vs. 22.79%; χ2=8.627, P<0.05). There was a significant difference in the detection of dyslipidemia among athletes engaging in different sport items (χ2=47.552, P<0.05), and a high detection rate of dyslipidemia was seen in baseball athletes (34.29%), softball athletes (37.04%), shooting/archery athletes (52.73%). Conclusion The prevalence of dyslipidemia was 25.87% among adult professional athletes in Guangdong Province, and high TC in combination with high LDL-C were the predominant type of dyslipidemia. The management of blood lipids should be given a high priority to male athletes and baseball, softball and shooting/archery athletes.

Objective To establish a high throughput phenotypic test for the detection of drug re-sistance in human immunodeficiency virus(HIV)strains. Methods The gene encoding luciferase was in-activated through restriction enzyme digestion and ligation. LacZ gene was used to replace the genes encoding original protease and reverse transcriptase. pol genes were amplified from pSG3△env plasmid and cloned in-to a new backbone plasmid through infusion. The factors that might affect the results of the test were opti-mized. Results The parental backbone plasmid pNL4-3. Lac was constructed,of which the gene encoding luciferase was inactivated and bearing the LacZ gene instead of genes encoding protease and reverse tran-scriptase. Several influential factors including cell numbers(10 000 / well),virus inoculation(200 TCID50 /well)and the concentration of DEAE-dextran(15 μg/ ml)were optimized. The reproducibility of this test was confirmed by testing 12 anti-HIV drugs against 2 pseudovirus strains 8 times,presenting the coefficient of variations(CVs)from 4. 32% to 28. 46% . Six types of pseudovirus were constructed and tested against the 12 anti-HIV drugs,the results of which were compared with those by using the pSG3△env-based pseud-ovirus test. The results of the two tests presented good consistency. Conclusion The high throughput phe-notypic test based on pNL4-3. Lac plasmid,combining the advantages of pSG3△env and pNL4-3 systems, could be used to analyze the drug resistance patterns of HIV-1 infectors and screen new drugs for antiretrovi-ral therapy in a rapid and effective way.

Objective To pan and characterize anti-HIV-1 Fab by the phage antibody library technology. Methods Total RNA were extracted from lymphocytes which were isolated from peripheral blood collected from asymptomatic HIV-1 infected donors with high titer antibody against HIV-1. The genes of heavy chains Fd fragment and light chains of antibody were amplified by RT-PCR. The phagmids pComb3X cloned Fd and light chain genes were transformed into E. coli XL1-Blue by electroporation to construct phage Fab library. By three runs of "absorption-elution-neutralization-enrichment", the clones were induced by IPTG and characterized by ELISA. The positive clones were sequenced and analyzed the sequences. Subsequently, Fab antibodies of these positive clones were induced to expressed and purified, then the recombinant virus neutralization assay was performed. Results A phage Fab library was constructed with 8×106 members, and 11 positive clones were obtained by detecting IPTG-induced-expressing Fabs with ELISA. By analysis of the sequences, 10 light chain genes and 8 Fd genes were ensured to be obtained. Compared with the genes of anti-HIV-1 antibodies in HIV sequence database, the gene sequences we obtained were highly homologous to some patent genes of anti-HIV-1 gp120 antibodies in HIV sequence database( light chains with 60%-90% identity, Fd with 71%-85% identity); The CDRs of these positive clones were determined by comparing the positive clone genes with antibodies' genes in V base database, furthermore, CDRH3 of these positive clones has the length of 12-22 aa. Strand shift had little effect to improving affinity of our Fab clones. Fab antibodies were induced to express at the concentration of ＞ 10 mg/L. Three Fab antibodies neutralize HIV-1 virus to some extent. Conclusion The studies will provide the basis on further study on the anti-HIV-1 Fabs obtained successfully.

Objective To compare cellular immune responses in mice elicited by Chinese different AIDS candidate vaccines.Methods According to their different immunization procedures,BALB/c mice were immunized with 6 AIDS candidate vaccines,separately.Spleen cells were isolated for the detection of cellular immune response to HIV-specific peptides using enzyme-linked immunosorbent spot(ELISPOT)assay and intracellular cytokine staining(ICS)method.Results AIDS vaccines were evaluated by using potential T-cell epitopes(PTE)Gag,Env and Pol peptides pool and ELISPOT.The positive conversion rates for cellular immune response of 1#-6# vaccines fluctuated from 70% to 100%.The vaccine-induced cellular immune responses to specific peptides pool are different not only in magnitude but also in breadth.The Th1type cytokines,IFN-γand IL-2,were detected with ELISPOT in 1# and 2# vaccines.The productions of IFN-γand IL-2 induced by both of the two vaccines showed a moderate correlation(r1 =0.62,P1 ＜0.01 ;r2=0.79,P2 ＜ 0.01).The positive conversion rate of IFN-γ secreting cells of 1 # vaccine was 66.7%(10/15)mice detected with both ELISPOT and ICS.And the results tested by ELISPOT and ICS showed moderate correlation(r = 0.55,P ＜ 0.05).Conclusion The magnitude and breadth of cellular immune responses induced by different AIDS candidate vaccines are different.Being induced by different AIDS candidate vaccines,the IFN-γand other Th1 type cytokines detected by ELISPOT or ICS could be used to evaluate the cellular immune responses in mice.

Objective To analyze the practicability of using ELISA kit for the detection of hepati-tis E virus antigen ( HEV-Ag) in plasma donations and Biomex HEV seroconversion panels. Methods The HEV-Ag positive samples were screened out from 36 340 donated blood plasma samples. Real-time fluores-cent PCR was performed for the detection of HEV RNA in HEV-Ag positive samples. The open reading frame 2 (ORF2) in HEV RNA was amplified by nested RT-PCR and the amplified products were confirmed by sequencing analysis. Phylogenetic tree was constructed for HEV genotyping. Five Biomex HEV serocon-version panels were used in this study for the detection of HEV-Ag, anti-HEV antibody and HEV RNA as well as the correlation analysis between HEV-Ag and HEV RNA. Results Twenty-six out of 36 340 plasma samples (0. 07%) were positive for HEV-Ag. Of the 26 samples, 25 samples were positive for HEV RNA as indicated by the results of nested RT-PCR and 23 positive samples were confirmed by sequencing analysis. The positive rate of HEV RNA in blood plasma donators was 1 ∶ 1 580 (0. 06%). There were 17 samples of genotype 1 (74%) and 6 samples of genotype 4 (26%) according to the phylogenetic tree analysis. All of the HEV-Ag positive samples were also positive for HEV RNA as indicated by the analysis of Biomex sero-conversion panels. HEV-Ag was consistent with the peak of the HEV RNA concentration. Conclusion A close relationship between HEV-Ag and HEV RNA was observed. HEV-Ag screening could be used as a measure to reduce the risk of HEV transmission by blood transfusion.