Objective To investigate the construction of Streptococcus mutans luxS gene knockout mutant which can act as the technical platform for following researches on luxS quorum sensing function in oral ecosystem.Methods Erythromycin resistance gene was inserted between two 1 kb fragments containing regions of DNA immediately upstream and downstream of the luxS translational start and stop codons.The resuhing construct was linearized and electro-transformed into Streptococcus mutans cells.After allelic exchange,the luxS gene knockout mutant strains were selected on 10μg/ml erythromycin plates,and compared the growth and biofilms formation of luxS knockout mutant with wild type strains.Results The luxSknockout mutant was confirmed by PCR,and it was also confirmed that this gene mutant could be stably passed through in vitro.The growth mode of luxS knockout mutant showed obvious difierences against that of wild type at stationary phase,the knockout mutant gained more bacteria cells growth.Conclusion Streptococcus mutans luxS gene has been successfully disrupted with allelic exchange.This mutant strains showed higher growth abilitv which could be the consequence of quorum sensing mutant.

Objective To explore the related factors with skin flap necrosis,we concluded the cases of patients with skin defects after free flap plantation.Methods From 2001 to 2016,188 cases about 20 influencing factors were analyzed (The characteristics of patients:age,sex,smoke,diabetes,high blood pressure;Preoperative factors:injured sections,injured causes,preoperative wound infection,preoperative wound osteomyelitis,the time from injury to operation;Intraoperative factors:operator,operation time,anesthesia time,intraoperative rehydration fluids,the way of vascular anastomosis,the number of venous anastomosis,the area of flap;Postoperative factors:flap hematoma,flap infection,vascular crisis) and multivariate logistic regression analysis was used to analyze the relationship between these risk factors and flap necrosis.Results All 188 cases were treated with free anterolateral thigh flap to repair soft tissue defect and it was revealed that the 174 cases were successful (92.55％) and 23 cases were occured vascular crisis (12.23％),8 cases were arterial crisis,11 cases were vein crisis,4 cases were ateriovenous crisis.After the treatment,the rescue was successful in 5 cases (38.46％).After the analysis we made the conclusion that the number of venous anastomoses,flap hematoma and vascular crisis were related with the skin flap necrosis.Conclusion The number of venous anastomose (≥2) will increase blood return to make the flap easier to survive.Intraoperative stanching and drainage tube placement work will reduce the skin flap hematoma as a result of reducing the skin flap necrosis.Artery and venous crisis handled in time,can enhance the survival rate of flap.

Objective To investigate the value of high-resolution 3.0T MR in the assessment of local infiltration of preoperative rectal cancer.Methods A total of 168 patients pathologically proved rectal cancer underwent both conventional pelvic and rectal high-resolution before operation, and the imaging findings were reviewed retrospectively.The accuracy of preoperative high-resolution 3.0T MR in prediction of pathological staging was assessed,and the characteristic imaging features of local infiltration in preoperative rectal cancer were discussed.Results The relationship between circumference invasion of colorectal cancer and the pathological T staging was moderately positive (rs=0.530,P=0.003).Compared the staging of colorectal cancer on MRI with pathologic T staging,the overall diagnostic accuracy was 84.52%,and there was a stronger correlation between MRI findings and pathological staging (rs=0.837,P=0.001).The best single parameters for diagnosing T3 stage rectal cancer on MRI were nodular convex of the tumor and muscular signal interruption,with 91.1% specificity and 89.7% sensitively respectively.And the best combination of parameters was the cord appearence of intestinal wall and muscular signal interruption,with 89.3% specificity and 78.0% sensitively respectively.Conclusion High-resolution 3.0T MR can be preferable to evaluating local infiltration of rectal cancer, showing a higher clinical value to asseee T staging of preoperative rectal cancer.

Objective To investigate the therapeutic effects of mesenchymal stem cells (MSC) on rat fulminant hepatic failure (FHF). Methods The rat MSC were separated and purified by adherent culture of whole bone marrow cells. The rat FHF models were established by CCl4 intragastric administration.The rats were divided into experimental group (n=20) and model control group (n=20).And the same dose of saline was administered to rats as normal controls (n=8).Dosage of 1.0 × 106 4',6-diamidino-2-phenylindole (DAPI) labeled MSC were transplanted into rats in experimental group and normal control group through caudal veins,and the same dose of saline was given intravenously in model control group.Part of rats in each group were sacrificed after 7 days and 14 days of injection to evaluate the general condition,survival rate,liver function,tumor necrosis factor (TNF)-α level,liver pathology and MSC homing to the liver between experimental group and model control group.Normal distribution data were compared by independent-sample t test and nonnormal distribution data were analyzed by non-parameter test.ResultsAfter 3 days of injection,the generalcondition of experimental group were better than the model control group. After 7 days of injection,there were 15 and 8 survival rats,the survival rates were statistically different between experimental group and model control group (x2 =4.122,P＜0.05).After 7 days and 14 days of injection,the liver function and TNF-α levels were statistically different between experimental group and model control group (both P ＜0.05),and liver pathology improvement in experimental group was more significant than model control group.DAPI labeled cells increased after transplantation in experimental group, whilefewDAPIlabeledcellswere observedinnormalcontrolgroup.ConclusionsMSC can home to liver of FHF rats after MSC allogeneic transplantation through caudal veins,which can improve liver immunity and liver tissue necroinflammation,and facilitate recovery of liver function.Therefore,it is demonstrated that MSC transplantation has obvious therapeutic effect on rat FHF.

Objectiv e To investigate the correlation between ( CAG) n repeat polymorphism of androgen receptor(AR)geneandmalebreastcancer.Methods 40casesofmalebreastcancerand40controlswerecol-lected.DNA was extracted from peripheral blood and the AR gene CAG coding exon sequences for PCR amplifica -tion,sequencing and calculated the number of CAG repeats frquency .χ2 test and Logistic regression analysis were used assess the AR gene CAG repeat length frequency affect the number of male breast cancer risk .Results There was statistically significant difference in male breast cancer cases and controls the number of CAG repeat length frequency.Man for whom the(CAG)n≥22 repeat sequence had 3.52 times risk of male breast compared (CAG)n≤22(OR=3.52,P=0.036).Conclusion AR gene CAG repeat length is a predictor of the frequency of male breast cancer risk .Longer CAG repeats can increase the risk of male breast cancer .

Objective Heart transplantation is an effective treatment of end-stage heart diseases and extending the time of donor heart preservation helps to make up for the shortage of donor hearts. This study was to investigate whether high-pressured mixed gas ( HPMG) of carbon monoxide and oxygen could prolong the time of donor heart preservation and its mechanisms. Methods Forty-eight C57BL/6 male mice aged 4-6 weeks were randomly divided in-to four groups of equal number:control ( the donor heart isolated but not transplanted) , immediate transplantation ( the donor heart transplanted right after isolated) , HTK-preservation ( the donor heart preserved in histidine-tryptophan-ketoglutarate solution for 24 hours after isolated, and HPMG preservation ( the donor heart preserved in an HPMG chamber with the oxygen partial pressure of 3200 hPa and carbon monoxide partial pressure of 800 hPa for 24 hours after isolated) .Another 36 recipient mice aged 6-8 weeks were randomly assigned to receive the donor heart immediately after harvested (n=12), preserved in HTK solution (n=12), or preserved in HPMG (n=12).At 2 hours after transplantation, the status of heart re-beating and cardiac function were compared among different groups of recipient mice.At 24 hours, tissues were taken from the transplanted hearts for examination of pathologic changes by HE stai-ning, detection of the apoptosis of cardiac cells by TUNEL, and determination of the expressions of microtubule-associated protein 1 light chain 3 -Ⅱ(LC3-Ⅱ) and B cell lymphoma/leukemia-2 (Bcl-2) by Western blot. Resul ts The re-beating rates of the imme-diately transplanted and HPMG-preserved hearts were significantly higher than that of the HTK-preserved ones (P<0.05).At 2 hours after transplantation, the cardiac function scores were 2.5 (2.0-2.9), 0.8 (0.5-1.0), and 4.5 (4.0-4.5) in the immediate implantation, HPMG-preservation and HTK-preservation groups respectively, with statistically significant differences between any two groups (P<0.05).The expressions of LC3-Ⅱand Bcl-2 were 2.06 ±0.29 and 0.87 ±0.18 in the HPMG-preserved heart recipients and 1.24 ±0.20 and 2.07 ±0.32 in the immediately transplanted heart recipients, both higher than 0.13 ±0.03 and 0.19 ±0.02 in the controls and 0.16 ±0.06 and 0.26 ±0.08 in the HTK-preserved heart recipients (P<0.05), the Bcl-2 higher in the HTK-pre-served heart recipients than in the controls (P<0.05), and the LC3-Ⅱ expression higher in the HPMG-preserved heart recipients than in the immediately transplanted heart recipients (P<0.05).HE staining showed that cell edema and inflammatory cell infiltration were more obvious in the HPMG-preserved heart recipients than in the controls and immediately transplanted heart recipients but less obvious than in the HTK-preserved heart recipients.The rate of cell apoptosis was dramatically increased in the HPMG-and HTK-pre-served heart recipients ([5.04 ±1.77]%and [26.72 ±5.23]%) in comparison with the controls ([1.08 ±0.56]%) (P<0.01) and immediately transplanted heart recipients ([2.13 ±1.71]%) (P<0.01) but decreased in the HPMG as compared with the HTK-preserved heart recipients (P<0.01). Conclusion High-pressured mixed gas preservation can reduce cold ischemia-reperfu-sion injury of the donor heart, which may be associated with its promotion of autophagy, provision of energy to cells, and apoptosis of cardiocytes in the donor heart.

Objective To analyze the incidence of hospitalized children with Henoch-Sch(o)nle in purpura (HSP) and Henoch-Sch(o)nlein purpura nephritis (HSPN) from 2009 to 2012,and to characterize the epidemiology of HSP and HSPN in Jiangxi province.Methods Inpatients of Jiangxi Children's Hospital with the diagnosis of HSP or HSPN were recruited during 2009 to 2012.The basic messages in the home page of medical records,such as the admission year,sex,age,area coming from were collected.Chi-square test was used for statistical analysis.Results A total of 2516 HSP pediatric patients were included in this study.Of whom,412 cases were diagnosed in 2009,568 cases in 2010,750 cases in 2011,786 cases in 2012.Among them,renal damage as the presenting symptom in 110 cases in 2009,148 cases in 2010,198 cases in 2011,and 196 cases in 2012.The average incidence of HSPN was 25.91％ (652/2516).The morbidity of HSPN were similar in different admission years (x2=0.62,P＞0.05).In HSP patients,the ratio between male and female was 1.59∶1; the peak age was 4 to 9 year-old (65.50％,1648/2516).The morbidity of HSPN was similar in both girls and boy patients group (x2=0.14,P＞0.05).The morbidity of HSPN was 18.76％ (163/869) in patients younger than 6 years old,which was lower than 26.85％(359/1337) in patients between age 6 to 11 years old,and the morbidity of HSPN was 41.94％ (130/310) in patients older than 11years old,the difference was significant (x2=65.24,P＜0.01).The morbidity of HSP in the month of year was different,the peak time was between October and December,which as 40.74％(1025/2516).The morbidity of HSPN was 30.23％(208/688) during January to March,higher than in other period of the year (x2=9.87,P＜0.05).In the last four years,there were 824(32.75％) hospitalized patients of HSP in Nanchang district,1692 cases (67.25％) in other areas in Jiangxi province.The morbidity of HSPN in Nanchang district was 17.35％ (143/824),compared with the average level 25.91％(652/2516),the difference was significant (x2=25.08,P＜0.01).Conclusion The number of children diagnosed with HSP is progressively increased from 2009 to 2012 in Jiangxi province.The peak period for HSP is between October and December,and the peak age is 4 to 9 year-old.The incidence of HSPN between January to March group is higher than in other periodof the year.The morbidity of HSPN is increased with age.

Microbial lipase,one of important industrial biocatalysts,has been used widely in many industrial and agricultural fields.It is always the research focus to screen,mine and develop the microbial lipases with novel catalytic activity and high stability.This paper introduces briefly the pathways and methods to mine novel microbial lipase resources from six aspects,including extremophile,metagenome,genome database,protein engineering,immobilization,chemical modification,etc.

Microbial lipases are important industrial biocatalysts with the character of stereoselectivity,site selectivity and high catalytic activity with few side effects.They have been used widely in many industrial and agricultural fields.The technology of protein engineering has been successfully applied to improve the activity and stability of microbial lipases,which will raise the competitive capacity of microbial lipase preparations and enlarge theirs application fields.The strategies,the problems and the prospects of protein engineering technology which have been applied to modify the microbial lipases was surveied.

Objective To explore and discuss the safety and treatment effect in intraoperative and postoperative intracerebral an-eurysm clip occlusion .Methods Retrospective analysis of 285 cases from April 2010 to April 2012 which underwent aneurysm clip occlusion was conducted .All patients received lumbar drainage surgery after anaesthesia .All patient′s complications were statisti-cally analyzed .Results In 285 patients ,no aneurysm rupture happened after drainage ;brain retraction syndrome′s incidence rate was 3 .00% ;cerebral vasospasm′s incidence rate was 11 .60% ;hydrocephalus′s incidence rate was 2 .10% ;intracranial infection′s incidence rate was 9 .10% .The mortality rate was 1 .05% .Conclusion Lumbar drainage is a safe ,effective ,simple treatment .It can effectively reduce the risk of aneurysm clip occlusion ,prevention and treatment of postoperative complications ,and ultimately im-prove the prognosis .