OBJECTIVE:To study the effect of EGCG-Zn chelated by epigallocatechin gallate (EGCG) and Zn ion on learn-ing,memory and antioxidant abilities in vascular dementia(VD)rats. METHODS:Rats were randomly divided into sham group, model group,zinc gluconate group (positive control,70 mg/kg),EGCG group (5 mg/kg),and EGCG-Zn low-dose,mid-dle-dose,high-dose groups (2,5,10 mg/kg),10 in each group. The VD models were induced by middle cerebral artery occlu-sion. The rats were intragastrically given relevant medicines after 7 d of modeling,once a day,for 28 d. Morris water maze were used to evaluate learning and memory abilities of rats. Spectrophotometric method was adopted to detect the superoxide dismutase (SOD),catalase(CAT),glutathione peroxidase(GSH-Px)activities and malondialdehyde(MDA)content in brain tissue of rats. RESULTS:Compared with sham group,escape latency was extended in model group,percentage of platform quadrant swimming distance(dP/dT)was reduced(P<0.01);SOD,CAT,GSH-Px activities in brain tissue were reduced,and MDA content was in-creased (P<0.01). Compared with model group,escape latency on 4th d of recording was obviously shortened in EGCG group and EGCG-Zn dose groups,dP/dT was obviously increased and dose-depended(P<0.05 or P<0.01);SOD,CAT,GSH-Px activi-ties in brain tissue were increased,MDA content was decreased(P<0.05 or P<0.01)and dose-depended. Compared with EGCG group and zinc gluconate group,escape latency was obviously shortened in EGCG-Zn dose groups,dP/dT was increased;SOD, CAT,GSH-Px activities in brain tissue were increased,MDA content was decreased;and the effects in high-dose,medium-dose groups were more obvious(P<0.05 or P<0.01). CONCLUSIONS:EGCG-Zn can improve the learning,memory and antioxidant abilities in VD rats,and the effect is superior to EGCG.

Objective To discuss the prevalence of non-EV71,non-CA16 virus strains of hand,foot and mouth disease(HFMD) in Guangdong province between 2008 and 2009,and analyze the genetic evolution of these non-EV71,non-CA16 virus strains.Methods Isolated viruses from stool samples collected from outpatient and in-patient cases of HFMD between 2008 and 2009 by human rhabdomyosarcoma(RD) cell and HEp-2 cell,cultures that exhibited a characteristic enterovirus cytopathic effect were evaluated by RT-PCR.Those strains which identified non-EV71,non-CA16 were analyzed by VP1 sequencing and then were identified by BLAST program.A phylogenetic tree was constructed using the Neighor-Joinning method in the MEGA 4.0 software.Results Twenty-two virus strains of non-EV71,non-CA16 were obtained,and nine of the twenty-two virus strains in 2008 were classified into CA2,CA4,and CB3 by BLAST; thirteen of the twenty-two virus strains in 2009 were classified into EV80,Echo13,Echo30,CBS,Echo24,CA10,CA6,and poliovirus 1 by BLAST.The honology of all strains was low,and all the strains belonged to CA,CB,Echoviruses,Enterovirus and poliovirus subgroup.Conclusion Except for EV71 and CA16 was a major causative agent in prevail of HFMD in Guangdong province between 2008 and 2009,there also existed other subgroup Enterovirus.The other twenty-two strains respectively belonged to CA,CB,Echoviruses,Enterovirus and poliovirus subgroup,and none of those strains was predominant.Muti-species Enterovirus occurred concomitantly.

Objective To understand the genetic characteristics of Enterovirus 71 ( EVT1 ) circu-lating strains of Guangdong province in 2008. Methods We isolated an EV71 strain from the fatal case of the hand, foot and mouth disease during an epidemic of Guangdong in 2008. Its complete genome was se-quenced and analyzed comparatively. Results The results showed that the full length of EV71 GDFS-3 ge-nome( not including poly A tail ) is 7405 bp. No insertion or deletion is detected in the coding region. There are several insertions and deletions in 5'and 3'UTR. Phylogenetic analysis of GDFS-3 and reference strains showed GDFS-3 strain shares the highest nueleotide homology with TW984 strain(96.0% ) but low homology with SIN5865, MS and BrCr( about 81.0% ). GDFS-3 strain also shares the highest amino acid homology with TW984 strain(99.0% ). It clustered with reference strains of CA subgenotype in the phylogenetie tree. The nucleotide identity with CA reference strains is 91.0% -95.0%. Conclusion The phylogenetic analysis based on the entire genome demonstrates that GDFS-3 strain has the nearest genetic relationship with TW984 strains ( isolated in 2004). GDFS-3 may belong to the same subgenogroup ( CA ) with Taiwan predominant strains. Otherwise,Some mutations in 5'UTR of EV71 may play the very important role in heightened viru-lence.

Objective To study the epidemic and genetic characteristics of coxsackievirus A6 ( CVA6) strains isolated in Guangdong province.Methods Enterovirus strains positive for neither entero-virus A71 ( EV71) nor CVA16 were isolated from Guangdong province during 2008 to 2013 to screen CVA6 isolates by real-time PCR.The entire sequences of viral genes encoding VP1 of CVA6 positive samples were amplified and sequenced.The phylogenetic analysis was performed to analyze the full-length gene sequences encoding VP1 of CVA6 isolates and sequences downloaded from GenBank by using DNAStar6.0 and MEGA5.2 software packages.Results CVA6 strains accounted for 61.4%of the 1672 non-EV71 and non-CVA16 enterovirus strains isolated in Guangdong province during year 2008 to 2013.The positive rates were respectively 10.5%(4/38), 66.7%(34/51), 36.2% (81/224), 63.0% (182/289), 62.3% (325/522) and 73.0%(400/548) from 2008 to 2013 and the differences among different years were significant (χ2=133.79, P<0.01).The CVA6 isolates could be classified into four clusters in the phylogenetic tree, designated A, B, C and D (including D1, D2 and D3 subgenogroups) genogroups.The four clusters shared nucleotide diversity ranging from 15.5% to 23.1%.The CVA6 strains isolated in Guangdong province shared 88.7%-100.0% homologies in nucleotide and 95.7%-100.0% in amino acid.Subtype D2 strains circulated during 2008 to 2012 and subtype D3 strains circulated during 2009 to 2013.Conclusion CVA6 strains were the predominant enterovirus strains among non-EV71 and non-CVA16 enterovirus strains circula-ted in Guangdong province from year 2008 to 2013.The CVA6 isolates could be classified into A, B, C and D genogroups based on the sequence analysis of VP1 region.Subgroups D2 and D3 isolates were identified and the subgroup D3 isolates were the prevalent strains in Guangdong.

Objective:To evaluate the immunogenicity of an experimental SARS-CoV inactivated vaccine.Methods:The virus suspension of F69 strain was inactivated with 0.4% formaldehyde and purified,then used as the immune antigen combined with Freund′s adjuvant.Eight adult New Zealand rabbits were immunized 4 times with this vaccine.12 sets of rabbit serum were sampled from the third day to 74th day after first immunization.Titers of specific IgG antibody and neutralizing antibody were determined by indirect ELISA and micro-cytopathic effect neutralizing test.Results:Rapid and potent humoral immune responses were induced by F69 inactivated vaccine in all eight immunized rabbits.Both specific IgG antibody and neutralizing antibody all peaked just with 2 vaccinations,with the maximum titer of 1∶81 920 and 1∶20 480 respectively about 6 weeks after first immunization.Across neutralizing reaction existed between F69 and Z2-Y3 strains.Conclusion:F69 inactivated vaccine owns strong immunogenicity.Similar antigenic epitopes exist between the F69 strain and Z2-Y3 strain,which ensured the cross neutralizing reaction.

Objective To investigate the correlation between the mutation of pncA gene and the susceptibility to pyrazinamide ( PZA) in Mycobacterium tuberculosis complex ( MTBC) strains and to analyze the mutation of panD and rpsA genes in wild type isolates without pncA gene mutation.Methods The sus-ceptibilities of 108 MTBC strains to first-line drugs including PZA were detected by using the MGIT 960 TB system.PCR was performed to amplify the 16S rDNA and pncA, panD and rpsA genes.The PCR products were analyzed by DNA sequencing analysis .Results Among the 78 multidrug-resistant MTBC strains , 47 isolates (60%) were resistant to PZA.Four out of 30 (13%) strains that were sensitive to ethambutol , iso-niazid, rifampicin and streptomycin (EIRS) were resistant to PZA.The drug-resistant MTBC strains showed higher resistance rate to PZA than that of the EIRS sensitive strains .There were 49 ( 96%) PZA-resistant isolates and 4 (7%) PZA-sensitive isolates occurred pncA gene mutation.Most of the pncA gene mutations in the genomes of PZA-resistant strains were base substitution mutation , especially the His57Asp substitu-tion.The pncA gene mutations centralized in the regions of 160-169, 203-289, 309-396 and 413-467.Seven novel mutation sites of pncA gene were observed including T175C, C188A, G insertion at 68, AGC insertion at 235, C insertion at 339, CC insertion at 392 and GT deletion at 395.The mutation sites founded in the genomes of PZA-sensitive strains were different from those of the PZA-resistant strains .No mutation of the pncA gene and the upstream regulatory sequence was found in two PZA-resistant strains , NJ44 and NJ108 . The sequence analysis of panD and rpsA gene showed that the NJ 108 strain had panD gene mutation at G419A, but no mutation was detected in the NJ 44 strain.Conclusion The multidrug-resistant MTBC strains showed higher resistance rate to PZA .The pncA gene mutation was common in PZA-resistant MTB strains and the panD gene mutation was also worthy of attention .

Objective To investigate the clinical features of of patients with Staphylococcus aureus blood-stream infection and risk factors for septic shock.Methods A total of 51 patients diagnosed with Staphylococ-cus aureus bloodstream infection in the hospital from January 2018 to March 2023 were enrolled in the study.According to whether the patients developed septic shock,they were divided into septic shock group and non-septic shock group.The clinical data of the patients were collected,and the clinical laboratory indicators were detected on the day of blood culture samples were collected.Bacteria isolated from blood culture specimens of patients were identified and tested for drug sensitivity.The clinical data and clinical laboratory test indicators of the two groups were compared.Multivariate Logistic regression was used to analyze the independent risk factors of septic shock in patients with Staphylococcus aureus bloodstream infection.The receiver operating characteristic(ROC)curve was used to analyze the predictive value of clinical laboratory test indicators for septic shock in patients with Staphylococcus aureus bloodstream infection.Results Septic shock occurred in 12 of 51 patients,with an incidence of 23.5％.The proportion of patients with diabetes,gouty arthritis,the proportion of patients with long-term glucocorticoid use,the proportion of patients with respiratory tract in-fection,the proportion of patients who died,and the hospitalization cost in the septic shock group were higher than those in the non-septic shock group,and the differences were statistically significant(P＜0.05).Long-term glucocorticoid use was an independent risk factor for septic shock in Staphylococcus aureus bloodstream infection(P＜0.05).The combination of C-reactive protein(CRP),albumin(Alb),neutrophil/lymphocyte ratio(NLR)and procalcitonin(PCT)had high value in predicting septic shock in patients with Staphylococ-cus aureus bloodstream infection,and the area under the ROC curve was 0.983.Conclusion Long-term use of glucocorticoids can lead to an increased risk of septic shock in patients with Staphylococcus aureus blood-stream infection.The combined detection of CRP,Alb,NLR and PCT has a higher predictive value than single detection for septic shock in patients with Staphylococcus aureus bloodstream infection.

Objective:To understand the etiology of a confirmed case of Coronavirus Disease 2019 (COVID-19).Methods:The pharyngeal swabs, serum and nasal swabs of a case of COVID-19 were inoculated into Vero-E6 cell tubes for virus isolation. The cytopathic effect (CPE) were observed daily. Collecting cell’s isolation when CPE was over 75%, after repeated freezing and thawing for 3 times, the supernatant was centrifugally taken, and the images of the virus were obtained by transmission electron microscopic observation, and the nucleic acid of the virus was extracted, second generation sequencing and sequence evolution analysis were used to identify and type the virus strains.Results:One strain of 2019 novel coronavirus (2019-nCoV) was successfully isolated from the nasal swab of this case of COVID-19, and one strain of herpes simplex virus type 1 (HSV-1) was also successfully isolated from the throat swab of the same case.Conclusions:COVID-19 cases have the possibility of co-infection with 2019-nCoV and HSV-1.

OBJECTIVETo evaluate the effectiveness of small interfering RNA (siRNA) on inhibiting severe acute respiratory syndrome (SARS)-associated coronavirus replication, and to lay bases for the future clinical application of siRNA for the treatment of viral infectious diseases.

METHODSVero-E6 cells was transfected with siRNA before SARS virus infection, and the effectiveness of siRNA interference was evaluated by observing the cytopathic effect (CPE) on Vero-E6 cells.

RESULTSFive pairs of siRNA showed ability to reduce CPE dose dependently, and two of them had the best effect.

CONCLUSIONsiRNA may be effective in inhibiting SARS-associated coronavirus replication.

Animals ; Cercopithecus aethiops ; RNA, Small Interfering ; pharmacology ; SARS Virus ; drug effects ; Transfection ; Vero Cells ; Virus Replication ; drug effects