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Objective To investigate the incidence and risk factors of hearing loss among the workers exposed to non -stationary noise.Methods A cross -sectional study was conducted among the participants.571 male workers without any history of ear disorder were enrolled in this study.They had been exposed to non -stationary noise for one year or more. The history of noise exposure,smoking and drinking behavior were interviewed by using a questionnaire.The noise exposure in the workplace was measured at eight -hour equivalent noise level (LEX.8h )and the thresholds of hearing at 500,1 000,2 000,3 000,4 000 and 6 000 Hz were detected.Results The prevalence of high -frequency hearing loss of two ears was 52.54%,while the prevalence of hearing loss of one ear was 71.98%.There were significant differences of prevalence among different groups of workers in LEX.8h ,duration of noise exposure and the cumulative noise exposure (CNE)(P <0.01).There was a dose response relationship between noise exposure and the risk of hearing loss (P <0.01).Conclusion Non -stationary noise exposure may contribute to hearing loss of workers.There is a good dose -effect relationship between the hearing loss and non -stationary noise.
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Objective To investigate the therapeutic effect of bone marrow mesenchymal stem cell (MSC)transplantation on cerebral ischemic reperfusion injury.Methods Sprague-Dawleye rat models of cerebral ischemiareperfusion injury were established with suture method.Ninety-six rats were divided into 4 groups:model group,MSC transplantation group,control group (injection of phosphate buffer saline,PBS) and sham operation group,with 24 rats in each group.The 6th generation of bone marrow MSCs cultured in vitro were selected and labeled with hoechst 33342,and then transplanted into rats through Penile vein 24 hours after the establishment of model.Equivalent PBS was injected into the control group.Neurological severity score (NSS) was assessed on the 2nd day,3rd day,4th day,8th day,15 th day,and the 22th day in each group.The plantation of MSC in the brain tissue was observed by fluorescence microscope.Furthermore,serial paraffin sections were subsequently stained with 2,3,5-triphenyl tetrazolium chloride,and immunohistochemistry stain with Nestin,neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP),which could be used as the specific markers of neural stem cells,neurons and astrocytes.Results The distribution of blue fluorescent in the impaired brain tissue could be seen at 2 days after transplantation of MSC,and it reached the peak at the 15th day.The result of immunohistochemistry showed that the cells positive for Nestin,NSE or GFAP in the impaired local brain tissue were increased greatly in the MSC transplantation group compared with the model group and control group,and the differences were statistically significant (all P ＜ 0.05).The scope of cerebral infarction in the impaired brain tissue diminished from the 8th day in the MSC transplantation group,the score of NSS was also decreased evidently,the differences were statistically significant compared with the model group and control group (all P ＜ 0.05).Conclusions Bone marrow MSC transplantation can increase the number of neural stem cells,neurons and astrocytes in the location of cerebral ischemic reperfusion injuries,which may promote the repairment of nerve injury.
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<p><b>OBJECTIVE</b>To investigate the expression pattern of hoxd3 gene during early embryogenesis and angiogenesis of wild-type zebrafish.</p><p><b>METHODS</b>Total RNA was extracted from embryos of zebrafish in different development stages by trizol. The cDNA of hoxd3 gene was amplified by RT-PCR. The RT-PCR product was ligated to pCS(2+) vector by T4 DNA ligatase polymerase and sequenced. T3 RNA polymerase in vitro transcription system was used to obtain the probe of digoxin-labeled anti-sense mRNA of hoxd3 gene. The expression pattern of hoxd3 was detected by whole embryo in situ hybridization (WISH) with anti-sense mRNA probe.</p><p><b>RESULTS</b>pCS(2+)-hoxd3 plasmid was successfully constructed, which was used to prepare anti-sense mRNA probe of hoxd3 in vitro. Expression pattern of hoxd3 gene was detected by WISH during zebrafish early embryogenesis and angiogenesis. It was observed that hoxd3 mRNA was expressed at the junction region of midbrain and hindbrain in wild-type zebrafish in embryos at 24 ≊72h postfertilization(hpf).</p><p><b>CONCLUSION</b>hoxd3 gene is mainly expressed in nervous system of wide-type zebrafish embryos.</p>
Subject(s)
Animals , Cloning, Molecular , Gene Expression Regulation, Developmental , Genetic Vectors , Homeodomain Proteins , Genetics , Metabolism , In Situ Hybridization , Plasmids , Genetics , RNA, Messenger , Genetics , Transfection , Zebrafish , Embryology , Genetics , Zebrafish Proteins , Genetics , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To study the susceptibility of Aedes albopictus to dengue virus infection.</p><p><b>METHODS</b>Aedes albopictus from 15 collections in Guizhou province were challenged orally with dengue virus 1-4 types, respectively. The total RNA from mosquitos were extracted. The viral NS1 gene fragment was amplified with reverse transcriptase polymerase chain reaction (RT-PCR). Dengue virus in mosquitoes was isolated with C6/36 cells. Then the viral antigen was detected by indirect immunofluorescence assay (IFA). Antigen and nucleic acid of dengue virus from 15 geographic strains of Aedes albopictus orally infected with dengue viruses (DEN-1, DEN-2, DEN-3 and DEN-4) were detected by IFA, RT-PCR and the virus was isolated with C6/36 cells, respectively.</p><p><b>RESULTS</b>The rates of Aedes albopictus orally infected with DEN-1, DEN-2, DEN-3 and DEN-4 were 12/15, 12/15, 8/15 and 13/15, respectively.</p><p><b>CONCLUSIONS</b>Different geographic strains of Aedes albopitus in Guizhou were susceptible to dengue viruses.</p>