OBJECTIVE:To optimize the extraction technology of asiaticosides from Centella asiatica. METHODS:Using to-tal amounts of asiaticoside and hydroxy asiaticoside as investigation indexes,single factor and orthogonal test were used to investi-gate the enzyme amount,enzymolysis time,enzymolysis temperature,ethanol volume fraction,liquid material ratio and ultrasonic extraction time and optimize the extraction technology of asiaticosides from C. asiatica by ultrasonic-enzyme method,and verifica-tion test was conducted. RESULTS:Optimal extraction technology was as follow as cellulose dosage of 12 mg/g,10-fold liquid ma-terial ratio added into 60% ethanol,enzyme hydrolysis for 60 min at 60 ℃,ultrasonic assisted extraction for 50 min. Average ex-traction rate of total asiaticosides was 1.92%(RSD=1.83%,n=3)in verification test. CONCLUSIONS:Ultrasonic-enzyme meth-od is stable and feasible for the extraction technology of asiaticosides from C. asiatica.

Objective To establish a method for the isolation of Zika virus and to gather experi-ences for viral isolation. Methods Suckling mice at age 1-3 days were inoculated with serum samples posi-tive for Zika virus through intracranial injection. All mice were sacrificed 6 days after the injection. Viral nu-cleic acids were extracted from brain, heart, liver, spleen, lung, kidney, muscle, skin and intestine tissue samples and analyzed by real-time RT-PCR. The supernatants of brain tissues positive for Zika virus were used for subculturing. Nested PCR was performed to amplify the NS5 gene of the isolated virus. The se-quences of NS5 gene were analyzed by using MEGA6. 0 software. Results All of the tissue samples were positive for Zika virus. Higher viral loads were detected in heart and brain tissue samples with cycle thresh-old (Ct) values of 24. 4 and 25. 3, respectively. The second generation of Zika virus was identified in suck-ling mice brain tissues 2 days after infection by using real-time RT-PCR. The amplified product of nested PCR was 972 bp in length. Sequencing analysis showed that the isolated Zika virus ( GDZ16002 strain) be-longed to the Asian lineage. Conclusion A strain of Zika virus was successfully isolated in China by using intracranial injection via a suckling mouse model. The isolated Zika virus belonged to the Asian lineage.

Objective To provide scientific evidences for Zika virus detection by clarifying the means by which Zika virus was discharged and the duration of corresponding processes. Methods Various samples of Zika cases were collected at different times and detected by using real-time RT-PCR. The positive samples were inoculated into cells and suckling mice through intracranial injection. The whole genome se-quences of those isolated Zika virus strain were sequenced and the results were further analyzed by comparing with the sequences of Zika virus from GenBank. Results The positive rates of Zika virus in urine, saliva and serum samples were 82. 4% (14/17), 82. 4% (14/17) and 52. 9% (9/17) respectively. The longest period of detected presence of Zika virus was found in urine samples amongst the three types of samples, fol-lowed by saliva and serum samples. Six Zika virus strains were isolated from 9 positive serum samples. Phy-logenetic analysis showed that the six genomes of Zika virus all belonged to Asia lineage, but located in two branches by Samoa and Venezuela strains. Conclusion This study indicated that urine, saliva and serum all could be used as the samples for routine detection of Zika virus. Urine and saliva samples showed higher detection rates of Zika virus RNA in comparison to serum samples, while Zika virus could be easily isolated from positive serum samples. Suckling mice were better for Zika virus isolation than cell lines.

Objective: To identify risk factors for positive surgical margin after laparoscopic radical prostatectomy. Method: The study retrospectively analyzed the records of 177 patients with prostate cancer who eventually underwent laparoscopic radical prostatecto-my from January 2016 to December 2017 in Peking University First Hospital. Age, prostate volume, prostate-specific antigen (PSA) be-fore needle biopsy, number of positive cores, positive percentage of needle biopsy and biopsy, and postoperative Gleason scoreand pathological stage were analyzed. Results: The overall positive surgical margin rate was 32.2% (57/177). Age, prostate volume, PSA be-fore needle biopsy, positive percentage of biopsy, and postoperative Gleason score were not significantly different (P>0.05). The study demonstrated significant differences between the number of positive cores, positive percentage of needle biopsy, and pathological stage (P<0.05). Multiple logistic regression revealed that the pathological stage was an independent factor affecting the positive surgi-cal margin rate (odds ratio, 1.616; 95% confidence interval, 1.062-2.459). Conclusions: The number of positive cores, positive percent-age of needle biopsy, and pathological stage significantly correlated with a positive surgical margin. The postoperative pathological T stage is an independent factor affecting positive surgical margins.

Objective To determine the electrocardiographic (ECG) characteristics of myocardial infarction (MI) evolution in rats and the intervention effect of Chinese herbs, and to provide basis for the establishment of the criteria for ECG diagnosis and assessment of drug therapeutic effects of rats MI. Methods Totally 140 male SD rats were randomly divided into sham operation group, model group, replenishing qi group, activating blood group, replenishing qi and activating blood (1∶2) and (2∶1) group as well as Tongxinluo group, each group with 20 rats. The rat MI model was established by ligating the left anterior descending coronary artery. The treatment groups were administrered with corresponding drugs by gavage from the first day after operation. The sham operation group and model group were given the same volume of distilled water. The 12-lead ECGs were recorded before, immediately after, 1st and 2nd week after operation respectively. The voltage value of ST segment deviation, the time limit of QRS complex and the number of animals with pathologic Q wave were evaluated for statistical analysis. Results Model group showed the elevation of ST segment, significantly prolonged time limit of QRS complex (P<0.01), and no pathologic Q wave showed immediately after operation compared with sham operation group. And all above observational indexes reached the peak at 1st week and declined at 2nd week after operation. Compared with model group at 2nd week after operation, replenishing qi and activating blood (1∶2) group and (2∶1) group all presented remarkable dropping of ST segment, shortening in time limit of QRS complex and reduction in number of rats with pathologic Q wave, of which 2∶1 group showed the most (P<0.01). Activating blood group only displayed decreases in time limit of QRS and number of rats with pathologic Q wave (P<0.05), and no significant decline in ST segment. Replenishing qi group demonstrated no significant changes in above three observational indexes (P>0.05). Thus, we proposed the criterion for the ECG diagnosis of rats MI as well as the criterion for the ECG assessment of drug therapeutic effects of rats MI. Conclusion ECG can overall and sensitively evaluate the evolution and drug therapeutic effects of MI in rats, thus providing a relatively objective and available assessment method for the experimental studies of myocardial ischemic diseases.

OBJECTIVE: To establish a non-invasive method for beta-thalassemia by detecting parental CD41-42 mutation in cell-free DNA derived from maternal plasma with droplet digital PCR (ddPCR). METHODS: Beta-actin gene and beta-thalassemia gene CD41-42 mutation were respectively set as the reference and target sequences. A novel method was established based on Bio-Rad ddPCR technique with specific primers and TaqMan probes for the two genes. The accuracy, sensitivity and detective linearity range of the developed method were evaluated by detection of the target gene gradient concentration samples. The applicability was also evaluated by testing 20 maternal plasma samples. RESULTS: The ddPCR method could accurately detect the beta-thalassemia CD41-42 mutation in cell-free DNA derived from maternal plasma. Within the target sequence concentration ratio of 5.00%-0.50%, the relative errors were all < 0.05, the linear regression equation was Y=1.0101-X-0.0071 and R=0.9994. The results of 20 maternal plasma cell-free DNA samples were all consistent with those of the follow-up testing. CONCLUSION A ddPCR method for detecting parental CD41-42 mutation in cell-free DNA from maternal plasma was developed. The method is simple, rapid, accurate, and can be applied for non-invasive prenatal diagnosis for couples simultaneously carrying the CD41-42 mutation.
Cell-Free Nucleic Acids ; DNA ; blood ; Female ; Humans ; Mutation ; Polymerase Chain Reaction ; Pregnancy ; Prenatal Diagnosis ; methods ; beta-Thalassemia ; diagnosis ; genetics

Objective: To develop a micro-neutralization test for determination of neutralizing antibody against ZIKA virus (ZIKV) in human sera and to verify the acute and convalescent serum samples of 10 ZIKA virus-infected cases diagnosed by nucleic acid detection and/or virus isolation. Methods: ZIKV isolated from ZIKA cases was used to determine micro-neutralization antibody. The virus solution was prepared by infecting BHK21, VERO and VERO-E6 cell lines and viral titer was tested; 100 TCID₅₀ viral solution and 4 times diluted sera which were inactivated at 56 ℃ for 30 min were neutralized, then added the cell suspension and incubated in 5% CO₂ incubator at 37 ℃ for 7 d. The CPE was observed every day. Results: The sensitivity of BHK21, VERO and VERO-E6 was different after infection with ZIKA virus. VERO cell line was the most sensitive and showed typical CPE. VERO cell line was used to establish a micro-neutralization test for determination of neutralizing antibody against ZIKA virus in sera. Conclusions The neutralizing antibody test for zika virus in sera is a special and usefulmethod to diagnose human infection of ZIKV and to conduct population based epidemiological investigation.