Objective To investigate the pollution of parasitic protozoa in drinking water and wastewater in Shenzhen in or-der to present evidence to establish the national hygienic standard for parasitic protozoa in drinking water.Methods Water samples of resource water,fin ished wa ter from3water plants,and post-treated wastewater samples from3wastewater treatment plants in Shenzhen city were collected.Para sitic pro tozoa Giardia lamblia Stiles and Cryptosporidiumparvum were detected by following steps:filtering,washing,magnetic isolation and staining.Results Giardia lamblia Stiles and Cryptosporidiumparvum were not found in samples from raw water and finished water,while they were found in post-treated wastewater samples from2wastewater treatment plants.Conclusion The results indicated that the prob lem of Giardia lamblia Stiles and Cryptosporidi -umparvum pollu tion in the water supplying systems didnt exist at present,but Giardia lamblia Stiles and Cryptosporidi umparvum in the post-treated wastewater were the potential pollution source to surface water.

Objective:The study is to investigate whether macrophage migration inhibitory factor(MIF)-173 single nucleotide polymorphism(SNP) correlates with inflammatory bowel disease(IBD) in Chinese Han population in Zhejiang Province.Methods:MIF-173 SNP alleles were typed using tetra- primer amplification refractory mutation system(ARMS) and restriction fragment length polymorphisms(RFLP)-PCR in 142 healthy subjects and 98 patients with inflammatory bowel disease(IBD),respectively.At the same time,the PCR products were cloned and sequenced.Results:We detected three kinds of genotypes at the MIF-173 locus,no deviation from Hardy-Weinberg equilibrium were observed.The result was the same from tetra-primer ARMS and RFLP-PCR.Statistical analysis showed,the frequency of MIF-173 CC genotype was significantly higher in patients with ulcerative colitis(UC) 15.5% than in healthy individuals 5.6%(P

Objective To determine the feasibility and accuracy of velocity propagation within main pulmonary artery(VP)from color M-mode Doppler imaging using custom software on a personal computer for noninvasive estimation of PVR.Methods Color M-mode imaging of pulmonary flow was obtained and then transferred to computer,the velocity propagation of pulmonary flow was automatically obtained.Comparative studies among Doppler echocardiography,personal computer and cardiac catheterization for predicting PVR had been done in 20 children with congenital heart disease and 20 normal children.Results Velocity propagations of children with congenital heart disease were significant lower than those of normal children obtained by color Mmode echocardiography[(38.38±18.89)cm/s VS(80.34±15.65)cms,P＜0.01),and correlated well with invasive PVR measurements(r=-0.69,P＜0.01).The correlation and repeatability of VP obtained by the custom software were better than VP obtained by Doppler echocardiography(r=-0.78,P＜0.01).A VP cutoff value obtained by the custom software of 35.910 had a sensitivity of 92.9% and a specificity of 100% to within pulmonary artery obtained by color M-mode echocardiography using custom software on a personal computer.

ObjectiveTo investigate the value of combined four-chamber view,left and right ventricular outflow tract view and three-vessel view of two-dimensional echocardiography (2DE) in prenatal screening for fetal congenital heart disease (CHD). MethodsFour combined views of 2DE were used to detect fetal hearts in 2419 fetuses at 21～ 25 gestational weeks.The echocardiograms were performed on all 2382 live-birth infants.Chi-square test was applied for statistical analysis.Sensitivity,specificity,positive predict value and negative predict value were calculated. Results The prevalence of fetal CHD was 11.62％ (281/2419).Among the 281 CHD fetuses,87.18％ were simple CHD (n=245) and 12.82％ were complex CHD (n=36).No difference was found in the positive rate of fetal CHD between the high-risk group and non-high-risk group [13.60％(34/250) vs 11.39％(247/2169),x2=1.069,P＜0.05].Thirty-six cases of CHD could be detected by the four combined views in prenatal screening with the sensitivity,specificity,positive and negative predictive value of 12.8％,99.8％,90.0％ and 89.7％,respectively.However,the diagnostic sensitivity of four combined views for simple CHD was 2.9％(7/245) and 80.6％(29/36) for complex CHD.The prevalence of neonatal CHD was 10.58％ (252/2382),including 241 with simple CHD and 11 complex ones. ConclusionsFour combined views of 2DE for prenatal screening is less sensitive in detecting simple CHD than complex CHD.Most of the complex CHD could be diagnosed by four combined views of 2DE before birth,but the misdiagnosis rate is high in simple CHD.The echocardiograms performed on newborns might make up for the lack.

Objective: To explore the association between light intensity physical activity (LPA) and sedentary behavior (SB) with body composition, so as to provide data references for improving adolescent physical health. Methods: From August 2020 to January 2021, general information of 694 students in grade one of a high school in Foshan City was collected, and the 24 hour activity behavior and body composition of the students were measured objectively by triaxial accelerometer and bioelectrical impedance tester. Dual component multivariate regression and dual compositional isotemporal substitution model were used to explore the relationship between LPA and SB and body composition. Results: LPA was associated with lower fat relative dominance (FRD) (male weekends FRD=-21.44%, female weekly FRD=-17.83%, weekdays FRD=-18.27%, P <0.05), and LPA was also associated with higher muscle relative dominance (MRD) and bone relative dominance (BRD) (male weekends MRD=12.78%, BRD= 12.87 %; female weekly MRD=11.64%, BRD=9.01%; female weekdays MRD=12.02%, BRD=9.23%, P <0.05). Replacing sedentary behavior (SB) with 10 minutes of LPA could reduce fat proportion [male:weekly -0.15(-0.26--0.04), weekdays -0.12 (-0.22--0.02); female:weekly -0.18(-0.27--0.08), weekdays -0.16(-0.25--0.07)) and increase muscle proportion (male:weekly 0.14(0.03-0.24), weekdays 0.11(0.02-0.21); female:weekly 0.17(0.07-0.26), weekdays 0.15(0.07-0.24)]. Conclusion Interrupting continuous SB with LPA can serve as an intervention measure to promote physical health and fitness in adolescents. School should encourage students to engage in frequent LPA during breaks and after school activities, while avoiding prolonged SB.

Objective:To construct recombinant influenza viruses expressing Gaussia luciferase (Gluc) with different influenza virus backbones and analyze their growth characteristics, genetic stability, ability to express Gluc and in vitro anti-influenza drug activity. Methods:The C-terminal of PR8NA was modified by inserting the porcine teschovirus-2A autocleavage peptide (P2A) and the Gluc-coding gene. Recombinant viruses, PR8NAGluc/PR8 and PR8NAGluc/WSN, were rescued using the eight-plasmid system of influenza virus reverse genetics, with seven plasmids derived from A/Puerto Rico/8/34(PR8) (H1N1) and A/WSN/1933 (WSN) H1N1. The genetic stability of the recombinant viruses was verified by RT-PCR. The fluorescence activity and the growth kinetics of the two recombinant viruses were compared. The correlation between the fluorescence activity of PR8NAGluc/WSN and median tissue culture infective dose (TCID 50), and the anti-drug activity of PR8NAGluc/WSN against oseltamivir, favipiravir, and Lianhua Qingwen in vitro were also analyzed. Results:The Gluc-expressing recombinant viruses constructed using PR8 and WSN backbones were successfully rescued by reverse genetics. Compared with the PR8 backbone, the WSN backbone significantly improved the fluorescence activity of Gluc. Moreover, the PR8NAGluc/WSN virus expressed stably in embryonated egg, and its replication kinetics was slightly lower than that of wild type. The fluorescence activity of PR8NAGluc/WSN virus had a good correlation with its TCID 50. The PR8NAGluc/WSN virus was sensitive to oseltamivir, favipiravir and Lianhua Qingwen. Conclusions:The recombinant virus with a WSN backbone exhibited higher fluorescence expression intensity as compared with the recombinant virus with a PR8 backbone. This study provided reference for high-throughput screening of anti-influenza drugs and the development of influenza virus vector vaccines.

Objective:To improve the consistency of test results through reducing inter-laboratory variation in SARS-CoV-2 antibody detection with WHO SARS-CoV-2 antibody candidate international standard (IS, sample G) and antibody reference panel (samples E, F, H, I, J).Methods:Ten WHO samples (A-J) including the candidate IS and reference panel were evaluated using different methods, such as microneutralization tests based on live SARS-CoV-2, pseudovirus neutralization assay and commercial ELISA kits. The test results were compared using statistical analysis.Results:Using IS (sample G) as a reference, the relative concentrations of other samples could be determined with less variation. ELISA and pseudovirus neutralization assay had consistent results with those obtained with the microneutralization test based on SARS-COV-2 strain HB02. Weakly positive samples could be detected only by a certain kit.Conclusions:The availability of an IS for antibodies would facilitate the standardization of SARS-CoV-2 antibody detection methods. The reference panel fitted all the assays based on the SARS-CoV-2 prototype Wuhan strain. Pseudovirus neutralization assay and ELISA could be used as alternatives to live SARS-CoV-2-based neutralization test to some extent.

Objective:To evaluate the immunogenicity of a novel influenza virus mRNA vaccine based on conserved antigens delivered by lipopolyplex (LPP) platform in a mouse model.Methods:Four copies of genes coding for extracellular domain of matrix 2 protein (M2e) and nucleoprotein (NP) of influenza A virus were synthetized after codon optimization. The fusion antigens were transcribed in vitro and delivered by LPP platform, named as LPP-4M2eNP. Expression of M2e and NP in eukaryotic cells was detected by immunofluorescence assay (IFA). BALB/c mice were inoculated intramuscularly twice with 10 μg or 30 μg LPP-4M2eNP vaccine at an interval of four weeks. Antibody response was detected by ELISA and cellular-mediated immunity (CMI) was detected by enzyme-linked immunospot assay (ELISPOT). Results:IFA showed that NP and M2e were expressed correctly in eukaryotic cells. Single dose immunization could induce significant antigen (NP, M2e)-specific CMI and antigen (NP, M2e)-specific antibody response was induced in mice with Th1 type bias after boost immunization. Moreover, NP-specific CMI was increased significantly after the second immunization, while no significant change in M2e-specific CMI was observed.Conclusions:Stronger CMI was triggered in mice by single dose of LPP-4M2eNP vaccine. Furthermore, robust humoral and cellular immune responses were induced after boost immunization. This study suggested that LPP-4M2eNP vaccine, which based on conserved antigen of influenza A and delivered by LPP platform, had great potential for development and application.