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.

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 .

Objective To analyze the relationship between the measured diameters of pituitary gland on MRI and peak-stimulated growth hormone(GH) in children with growth hormone deficiency (GHD).Methods A total of 46 children with GHD were included in this study, and 30 healthy children who were admitted to the hospital for health check-up were acted as the control group during the same period.The measured diameters of pituitary gland on MRI were compared between the two groups and the correlation between the diameters of pituitary gland on MRI and peak-stimulated GH were analyzed.Results ① The coronary and sagittal heights of pituitary gland on MRI were greater in children aged 7-10 years old and older than 10 years in control group and in children older than 10 years in observation group than those in children younger than 6 years (P<0.05).The anteroposterior diameter of pituitary gland on sagittal MRI in the control group was increased (P<0.05).The coronal height, sagittal anteroposterior diameter and sagittal height were lower in the observation group compared with age-and gender-matched controls(P<0.05).②The peak-stimulated growth hormone levels were higher in children aged 7-10 years old and older than 10 years in both groups compared with children younger than 6 years old (P<0.05).The peak-stimulated GH were lower in observation group compared with age-and gender-matched controls(P<0.05).③ The heights of pituitary gland on coronary and sagittal MRI in children with GHD were positively related to the peak-stimulated GH, and coronary height had the highest correlation(P<0.05).Conclusion The heights of pituitary gland on coronary and sagittal MRI in children with GHD are positively related to the peak-stimulated GH.The growth and development of children can be predicted by monitoring the changes of GH levels.

Objective To analyze the feasibility of body surface electrodes instead of multipair esophageal electrodes for the evaluation of neural respiratory drive in patients with COPD. Methods Diaphragm electromyo-gram(EMG)from body surface electrodes and multipair esophageal electrodes,was recorded in 29 patients with stable COPD recruited from outpatient clinic. Changes of neural respiratory drive of two kinds of electrodes during resting and maximal isocapnic ventilation (MIV) were observed before and after inhalation of bronchodilators. Results Ventilation significantly improved ,RMS-sur and RMS-eso significantly decreased after the inhalation of bronchodilators during resting and MIV. RMS-sur and RMS-eso were significantly correlated(r=0.660,P<0.01). Conclusion EMG from the surface electrodes may be a useful and noninvasive technique to evaluate neural respi-ratory drive in patients with COPD.