Estimating the basic reproduction number of COVID-19 in Wuhan, China / 中华流行病学杂志

Objective@#The number of confirmed and suspected cases of the COVID-19 in Hubei province is still increasing. However, the estimations of the basic reproduction number of COVID-19 varied greatly across studies. The objectives of this study are 1) to estimate the basic reproduction number (R0) of COVID-19 reflecting the infectiousness of the virus and 2) to assess the effectiveness of a range of controlling intervention.@*Method@#The reported number of daily confirmed cases from January 17 to February 8, 2020 in Hubei province were collected and used for model fit. Four methods, the exponential growth (EG), maximum likelihood estimation (ML), sequential Bayesian method (SB) and time dependent reproduction numbers (TD), were applied to estimate the R0.@*Result@#Among the four methods, the EG method fitted the data best. The estimated R0 was 3.49 (95% CI: 3.42-3.58) by using EG method. The R0 was estimated to be 2.95 (95%CI: 2.86-3.03) after taking control measures.@*Conclusion@#In the early stage of the epidemic, it is appropriate to estimate R0 using the EG method. Meanwhile, timely and effective control measures were warranted to further reduce the spread of COVID-19.

Detection of parvovirus B19 viral DNA in serum of women of childbearing age in Xiangyang City / 公共卫生与预防医学

Objective To analyze the infection of human parvovirus B19 among women of childbearing age in Xiangyang City, and to provide a reference for pregnant women's health care. Methods A total of 303 women of childbearing age in Xiangyang City from 2018 to 2019 were selected as the research subjects. B19 virus DNA in serum of the subjects was detected by nested PCR technology. The differences in the detection rate of B19 viral DNA among normal pregnancy, abnormal pregnancy, and infertility serum were statistically analyzed. The differences in the detection rate of B19 virus DNA among women of childbearing age at different ages were compared. Results The detection rate of B19 viral DNA in all 303 women of child-bearing age was 27.72%. The detection rate of B19 virus DNA in 26-35 year old women was higher than that in other age groups. The detection rate of B19 virus DNA in abnormal pregnancy group was significantly higher than that in normal pregnancy group (P <0.05). Conclusion The detection rate of B19 virus DNA in abnormal pregnancy and infertility group was significantly higher than that in normal pregnancy group, with the detection rate of B19 virus in 26-35 year old women of childbearing age being the highest among all age groups. It is necessary to strengthen the screening of B19 virus in pregnant women of childbearing age in this region to reduce its impact on fetal abortion.

Estimating the basic reproduction number of COVID-19 in Wuhan, China / 中华流行病学杂志

Objective The number of confirmed and suspected cases of the COVID-19 in Hubei province is still increasing. However, the estimations of the basic reproduction number of COVID-19 varied greatly across studies. The objectives of this study are 1) to estimate the basic reproduction number ( R 0 ) of COVID-19 reflecting the infectiousness of the virus and 2) to assess the effectiveness of a range of controlling intervention. Method The reported number of daily confirmed cases from January 17 to February 8, 2020 in Hubei province were collected and used for model fit. Four methods, the exponential growth (EG), maximum likelihood estimation (ML), sequential Bayesian method (SB) and time dependent reproduction numbers (TD), were applied to estimate the R 0 . Result Among the four methods, the EG method fitted the data best. The estimated R 0 was 3.49 (95% CI : 3.42-3.58) by using EG method. The R 0 was estimated to be 2.95 (95% CI : 2.86-3.03) after taking control measures. Conclusion In the early stage of the epidemic, it is appropriate to estimate R 0 using the EG method. Meanwhile, timely and effective control measures were warranted to further reduce the spread of COVID-19.

The value of diffusion kurtosis imaging combined with diffusion weighted imaging in evaluating the microstructure of cerebral gray and white matter in chronic mountain sickness / 实用放射学杂志

Objective To explore the gray and white matter microstructures in the brain of patients with different degrees of chronic mountain sickness(CMS).Methods 30 cases of CMS (10 cases in each group divided into mild,moderate and severe groups according to the severity)were collected as experimental group,and 10 normal adults in high altitude area were collected as the normal control group.All cases underwent MRI conventional head sequences,diffusion weighted imaging (DWI)and diffusion kurtosis imaging (DKI)sequences.The values of mean kurtosis(MK),radial kurtosis(RK),kurtosis anisotropy(KA)and apparent diffusion coefficient(ADC) graphs were reconstructed by post-processing software respectively.Selected the region of interest(ROI)symmetrically and fixedly, then measured and analyzed the parameter values of ROI in the same area.Results Compared the CMS groups with normal control group,the diffusion parameters and ADC values in certain parts of deep gray matter nucleus and white matter fibers were statistically significant,and the difference was significant with the progression of the disease.Conclusion DKI combined with DWI has certain value in evaluating the gray and white matter microstructure of human brain,there are some difference in the brain microstructure between CMS patients and high altitude normal subjects,additionally,the difference in different degrees of CMS is diverse.

Xinfukang drug-containing serum on bone marrow stem cell transcription and secretion of SDF-1α / 国际生物医学工程杂志

Objective To clarify the effects of Xinfukang containing-serum on stromal cell-derived factor-1α (SDF-1α) translation and protein secretion of bone marrow stem cells (BMSCs).Methods BMSCs were isolated and amplified using bone marrow culture method,and were identified by flow cytometry.mRNA and protein secretion of SDF-1α were detected by quantitative PCR (q-PCR) and enzyme linked immunosorbent assay (ELISA),respectively.Results The expression of SDF-1α mRNA were significantly increased after 72 h in drug-containing serum,and SDF-1α mRNA in the experimental group was approximately 200 times as that in the control group (P＜0.05).Secretion of SDF-1 α in the experimental group (277.561 1 ± 15.651 8) pg/ml was nearly doubled compared with that in the control group (153.107 1±14.765 1) pg/ml (P＜0.05).Conclusions BMSCs from whole bone marrow adherent culture have high purity,and drug-containing serum can promote BMSCs to express SDF-1 α mRNA and secretion of SDF-1 α.

Progress of research on application of quantum dots in tissue engineering / 生物医学工程学杂志

Quantum dots (QDs) are novel photo-stable semiconductor nanocrystals with wide excitation spectra and narrow, symmetrical emission spectra. QDs can be used as molecular probes by conjugating to a wide range of biological targets, including proteins, peptides and nucleic acids. It has been widely used in bio-labeling, fast detection and biological imaging. In this review, we focus on the applications of QDs in tissue engineering and its potential bio-safety issues.

Light-cured composite resin materials for dental crown defective repair / 中国组织工程研究

BACKGROUND:Light-cured composite resin is used for dental crown defective repair in terms of both function and morphology. OBJECTIVE:To investigate the therapeutic effects of light-cured composite resins on crown defects. METHODS:Relevant literatures concerning light-cured composite resins for repair of crown defects were retrieved. Literatures which met the study standard were deeply analyzed. Meanwhile, fol ow-up results and literature results were compared for patients receiving light-cured composite resins for repair of crown defects to identify the feasibility of light-cured composite resins for repair of crown defects. RESULTS AND CONCLUSION:Based on the included data, the successful rate of light-cured composite resins for repair of crown defects was over 90%. Clinical fol ow-up of 12 patients undergoing light-cured composite resin showed that the repaired crowns were stable and fixed, and exhibited a symmetrical appearance with the contralateral namesake tooth of the adjacent tooth, and there was a normal bite relationship. During the fol ow-up study, 19 teeth repaired from 12 patients had no loosing, no shedding, no percussion pain and normal bite relationship. X-ray films showed no apical shadows. Light-cured effects were limited to the upper and middle parts but not to the apical part. Therefore, a better therapeutic effect can be obtained.

Effects of tooth germ microenvironment in vitro on the differentiation of dental pulp stem cell and ectoblast mesenchyme stem cell / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the differential ability of dental pulp stem cell (DPSC) and ectoblast mesenchyme stem cell (EMSC) that were cultured with tooth germ cell (TGC) as the tooth germ microenvironment.</p><p><b>METHODS</b>The TGC of 4-day old rat was used as the tooth germ microenvironment. The BrdU marked and determined DPSC and EMSC were cultured with the TGC respectively. The expression of cell surface antigen dentin sialoprotein (DSP) and alkaline phosphatase (ALP) activity were determined with double marker immunofluorescence. The differential ability of DPSC and EMSC were determined by the immunohistochemistry and image analysis in the tooth germ microenvironment.</p><p><b>RESULTS</b>The transformation efficiency of DSP positive cell in the EMSC co-culture group was higher than that in the DPSC co-culture group (P < 0.05). The transformation efficiency in the co-culture groups was higher than that in the non co-culture group after 7 days by the image analysis of immunohistochemistry (P < 0.05). The ALP activity in the co-culture groups increased after 3 and 7 days. The ALP activity in the EMSC co-culture group was higher than that in the DPSC co-culture group.</p><p><b>CONCLUSION</b>DPSC and EMSC cultured with TGC as the tooth germ microenvironment can be induced to differentiate into odontoblast. The ability of EMSC is higher than that of DPSC.</p>

Effects of Exercise and Estrogen Replacement on the Content of Nitric Oxide and Expression of eNOS and iNOS in Liver of ovariectomized Rats / 中国运动医学杂志

Objective In this study,the effects of moderate treadmill exercise and estrogen replacement treatment on the production of liver nitric oxide(NO)and the expression of endothelial nitrie oxide synthase(eNOS)and inducible nitric oxide synthase(iNOS)in ovariectomized(OVX)rats were observed.Methods Female mature SD rats were randomly divided into six groups according to their body weight:sham group(group S),sham exercise group (group S+EX),group OVX,OVX+exercise group (group OVX+EX),OVX+estrogen group(group OVX+E_2),and OVX+exercise+E_2 group(group OVX+EX+E_2).The rats ran on the treadmill at a speed of 18m/min for 60min,5 times per week.50μg/kg of E_2 was given subcutaneously three times per week to groups OVX+E_2 and OVX+EX+E_2.After 14 weeks,NO production in the liver was determined by nitrate reductase method.Protein expression of eNOS and iNOS was determined by immunohistochemistry.Results The NO content of group S was significantly lower than that of group S+EX,but significantly higher than that of group OVX.The NO content of groups OVX+EX,E_2,and OVX+EX+E_2 were significantly higher than that of group OVX.The positive reaction of eNOS mainly located in the cytoplasm of hepatocytes and endothelial cells of the hepatic sinusoids in all groups.The changing tendency after exercise or/and estrogen replacement was almost similar with that of the content of NO.The positive reaction of iNOS mainly located in the cytoplasm of hepatocytes in groups S,S+EX,E_2,and OVX+EX+E_2,while it located in the nuclei in both groups OVX and OVX+EX.Conclusion Moderate exercise and estrogen supplementation both had the same effect of upregnlated synthesis of NO in liver of ovariectomized rats.

Initial lumbar stability following transforaminal interbody fusion: Biomechanical test / 中国组织工程研究

BACKGROUND:Transforaminal lumbar interbody fusion(TLIF)can be applied in any lumbar segment,and retain integrity of lateral vertebral plate and zygapophysiai joints.However,few studies have been conducted about the biomechanical performance.OBJECTIVE:To explore the stability of lumbar intervertebral segment following TLIF appHed bilateral and unilateral transpedicular screws fixation.DESIGN,TIME AND SETTING:Biomechanical test was performed at the Institute of Biomechanics,Shanghai University and Nantong University between August 2005 and April 2006.MATERIALS:Twenty samples of fresh one-month-old calf lumbar vertebra.METHODS:Twenty samples of calf lumbar vertebra underwent TLIF alone,TLIF in combination with bilateral or unilateral transpedicular screws fixation.Biomechanical test was performed on spinal three dimensional motion testing machine.MAIN OUTCOME MEASURES:Stress,displacement.strain and torsion angle were recorded.RESULTS:After TLIF without fixation.no obvious changes were found in mean stress and strain,but the axes stiffness and rotational stiffness were significantly decreased,indicating TLIF could produce immediate lumbar stability.After TLIF with unilateral or bilateral transpedicular screws fixation,the lumbar stability was significantly enhanced compared with TLIF alone,especially bilateral transpedicular screws fixadon.Although the lumbar stability following unilateral transpedicular screws fixation was inferior to bilateral fixation,it was still greatly enhanced,even bxceeded normal sample,indicating TLIF with unilateral transpedicular screws fixation could produce enough initiallumbar stability.CONCLUSION:TLIF alone cannot support sufficient initial stability,but TLIF with bilateral and unilateral transpedicular screws fixation can enhance lumbar initial stability.