Objective To investigate genotypes and antimicrobial susceptibility of Rhizobium radiobacter (R.radiobact-er)isolated from pediatric patients with bacteremia.Methods R.radiobacter strains from blood cultures of pediatric pa-tients with bacteremia from February 2013 through February 2014 were collected.16S rDNA fragment was amplified by polymerase chain reaction(PCR),bacterial genotypes were identified by pulsed-field gel electrophoresis (PFGE),antimi-crobial susceptibility testing were performed by Kirby-Bauer disk diffusion method.Results 13 isolates of R.radiobacter were isolated from 12 children with positive blood culture,which including 3 genotypes,the homology of 16S rDNA fragment and R.radiobacter IFM 10623 was up to 99%.According to CLSI 2003 standard,these 13 R.radiobacter were resistant to ceftazidime,piperacillin,ticarcillin,piperacillin/tazobactam,ticarcillin/clavulanic acid,aztreo-nam and polymyxin B,but sensitive to cefepime,doripenem,imipenem,meropenem,tobramycin,netilmicin,cip-rofloxacin,levofloxacin,and norfloxacin.In addition,cefotaxime and ceftriaxone showed larger inhibition zone. Conclusion Therapy of R.radiobacter infection should be based on antimicrobial susceptibility testing results;cefo-taxime and ceftriaxone are better selection for the therapy of R.radiobacter infection in pediatric patients.

Objective To evaluate diagnostic method and infection factors for catheter-related bloodstream infec-tion(CRBSI)due to Rhizobium radiobacter (R.radiobacter)in pediatric patients.Methods Clinical data of 1 014 pediatric patients with central venous catheter(CVC)-related treatment in a hospital from February 2012 to February 2014 were collected,semi-quantitative culturing of catheter,colony forming unit (CFU)ratio of catheter to venous blood,difference in culture time between venous blood and catheter were detected among patients with R.radiobact-er infection;factors for R.radiobacter infection were analyzed.Results Of 1 014 pediatric patients who used CVC, 32 were detected R.radiobacter from catheter blood,28 were detected from venous blood,27 were detected from both catheter and venous blood.Catheter semi-quantitative culture of 27 patients were ≥ 15 CFU,5 were< 15 CFU;CFU ratio of catheter to venous blood of 22 patients were ≥5:1,6 were<5:1;difference in culture time be-tween venous blood and catheter of 26 patients were ≥2 hours,2 were<2 hours.Risk factor analysis revealed that child’s age,catheter indwelling time of each group were significantly different (both P <0.05).Conclusion Cathe-ter semi-quantitative culture,CFU ratio of catheter to venous blood,and difference in culture time between venous and catheter blood are important diagnostic basis for confirming R.radiobacter bloodstream infection;patients aged <2 years,catheter indwelling time >5 days are risk factors for R.radiobacter bloodstream infection.

Objective To investigate the effect of α7nAchR gene 713T>C mutation on the cognitive function and Aβ expression in Alzheimer′s disease(AD)mice.Methods Twenty APPSwe transgenic APPa7KO mice(6 months old,α7nAchR gene knockout)were divided into the mutation type group and wild type group according to the random number table method,10 cases in each group.The mutation type and wild type of AVV-α7nAchR cDNA were respectively injected by lateral ventricle,once per month,for 6 times.The change of cognitive function in mice was examined by Morris water maze.The ELISA method was used to detect Aβ 40 and Aβ 42 expression levels.The Aβ plaque deposit situation was detected by the immunochemical method.Results Compared with the mice in the wild type group,the escape latency and the time of first time to find the platform of the mice in the mutation type group were significantly extended,while Hippocampal Aβ40 and Aβ42 expression levels were significantly increased,the difference was statistically significant(P＜0.05).Conclusion α7nAchR gene 713T>C mutation aggravates the cognitive function impairments in AD mice and hippocampal neuron Aβ expression level.

Objective Respiratory variations in the pulse oximetry plethysmographic waveform amplitude (△POP) have been popularly studied as a dynamic indicators for fluid responsiveness assessment.The authors hypothesized that △POP can indicate fluid responsiveness in septic shock patient in emergency department.Methods A prospective study of 28 patients with septic shock was carried out in Emergency Room and Emergency Intensive Care Unit from 1 October,2010 to 30 September,2011.Hemodynamic data including cardiac index,stroke volume Variation (SVV) and △POP were recorded before and after volume expansion treatment.Fluid responsiveness was defined as an increase in cardiac index of 15％ or greater.Results Changes in △POP after volume expansion were greater in responders than that in non-responders (P ＜ 0.01).There was a significant relation between △POP and SVV before volume expansion (r =0.900,P ＜ 0.0001).Conclusions △POPcan indicate fluid responsiveness non-invasively in septic shock patient in emergency department.This marker has potential clinical application with high sensitivity and reliability.

Objective To evaluate HBeAg quantification in predicting the efficacy of pegylated interferon (PegIFN) α treatment for patients with HBeAg-positive chronic hepatitis B (CHB).Methods A total of 216 HBeAg-positive CHB patients admitted in Ningbo No.2 Hospital during March 2009 and December 2011 were enrolled in the study.All patients were given subcutaneous injection of PegIFNα-2a or PegIFNα-2b weekly for 48 weeks and followed up for 24 weeks after discontinuation.Patients were divided into HBeAg seroconversion group and non-seroconversion group at the end of the follow-up.Receiver operating characteristic (ROC) curves were used to evaluate HBeAg levels at baseline and 12,24 weeks of treatment in predicting HBeAg seroconversion.Results HBeAg seroconversion was observed in 31.48％ (68/216) patients at the end of follow-up,and there was no significant difference in seroconversion rate between patients treated with PegIFNα-2a and those with PegIFNα-2b (32.00％ vs.29.27％,P ＞ 0.05).There was significant difference in baseline HBeAg levels between patients with HBeAg seroconversion and those without HBeAg seroconversion (Z =-3.834,P ＜ 0.05).HBeAg seroconversion patients had a tendency of rapidly decreasing HBeAg level,but there was no significant difference in decreasing rate between seroconversion and non-seroconversion patients (F =3.321,P ＞ 0.05).ROC curves showed that HBeAg level at 24-week was the best indicator for predicting HBeAg seroconversion with area under curve of 0.861.Conclusion Serum HBeAg level at 24-week of treatment may be used to predict the HBeAg seroconversion in HBeAg-positive CHB patients treated with PegIFNα.

Objective To investigate the efficacy of polyethylene glycol (PEG)-interferon α (PEG-IFNα) in treating HBeAg-positive chronic hepatitis B (CHB) and explore the relationship between hepatitis B virus (HBV) genotypes and the effect of interferon α (IFNα) therapy.Methods A total of 199 CHB patients with known genotypes were given subcutaneous injection of PEG-IFNα-2a or PEG-IFNαt-2b once a week for 48 weeks,with another 24 weeks follow up.The seroconversion of HBeAg influenced by HBV genotypes were analyzed after discontinuation of treatment.Results In local area,genotype C was the major genotype[64.32％ (128/199)].Except serum ALT and AST level,the differences in gender,age,liver inflammation,degree of liver fibrosis,HBeAg level and HBV DNA level between genotype B and C were not statistically significant(all P ＞0.05).The seroconversion rate of HBeAg in patients with genotype B at early stage of therapy (3 months) was significantly higher than that of patients with genotype C [26.76％ (19/71) vs 10.16％ (13/128),x2 =9.330,P =0.002].While at the end of follow-up,seroconversion rate of HBeAg in patients with genotype B (followed up for 6 months) was higher than that of patients with genotype C [39.44％ (28/71) vs 30.47％ (39/128)],but the difference was not statistically significant(x2 =1.645,P =0.200).By univariate analysis based on log-rank test,the time of HBeAg seroconversion in patients with genotype B was much earlier than that of genotype C [(13.99 ± 0.67) months vs (15.47 ± 0.41)months],but the difference was not statistically significant (P =0.150).Conclusions The seroconversion rate of HBeAg in patients with genotype B treated with PEG-IFNα was significantly higher than that of genotype C in early stage of therapy (3 months),while similar at the end of therapy.

Objective To observe the effects of sleep deprivation(SD)on learning and memory and phos-phorylated cyclic AMP responsive element binding protein(pCREB) expression in hippocampus of mice,and to explore the mechanism of cognitive change after SD. Methods Twenty female C57BL/6J mice were randomly divided into sleep deprivation group(SD, n = 10) and normal cage control group (CC,n = 10). Touch method was used to establish the sleep deprivation model. 30 days after SD,all the animals were subjected for Morris Water Maze (MWM) to test mean escape latency and percentage of time spent in the target quadrant. pCREB level in hippocampus was tested with Western blot. Results The mean escape latency in SD group in the second and third day of MWM was (29.31 ±4.93) s and (25.33 ±5.06)s, respectively, and was longer than that in CC group ((26.05 ±5.96)s and (19.35 ±7. 85)s,respectively). Mice in SD group spent less time in the target quadrant than that in CC group((23.61 ±9.86)% and (37.46 ±7. 51)%,.respectively, P<0.05). Results of Western blot for pCREB revealed that the pCREB level in hippocampus in sleep deprivation group was significantly lower than that in control group(0.71 ±0.03 and 0.82 ±0.06, respectively, P<0.01) . Conclusion The impairment of spatial learning and memory ability in sleep deprivation animals may be associated with the reduction of pCREB in hippocampus.

Objective To study the risk factors associated with death of patients suffered from acute exacerbation of interstitial pneumonia (AE-IP) with very high mortality and very difficult to handle so as to find the most suitable treatment strategy for these patients.Methods The data of 26 patients with AE-IP admitted to Emergency Intensive Care Unit in Peking Union Medical College Hospital from September 2010 to September 2013 were restrospectively analyzed.Comparison of general condition of patients,treatment strategy and response to non-invasive ventilation of patients was made between survival group and death group.Results There was no significant difference in general condition of patients between death group and survival group.But compared with idiopathic pulmonary fibrosis (IPF),connective tissue disease-related interstitial pneumonia had a tendency to accounting for higher proportion in the survival group.The rats of endotracheal intubation and invasive ventilation were significantly increased in death group (14％ vs.84％,P ＜ 0.05).There was significant improvement in PaO2/FiO2 after non-invasive ventilation for 2 hours in the survival group (176 ± i10 vs.218 ±64,P ＜0.05) while the death group had no significant improvement.Conclusions In patients with AE-IP,connective tissue disease associated interstitial pneumonia might have better outcome than IPF.AE-IP patients have a very high mortality rate once patients intubated,thus the decision of intubation in such patients needs to be very cautious.The patients with negligible improvement in PaO2/FiO2 after non-invasive ventilation for 2 hours may have a poor prognosis.

Objective To analyze and evaluate the final examination paper of Neurology and Phychiatry.Methods We randomly selected 65 examination papers for year 2003 students specializing in clinic medicine and analyzed them.Results The students'scores were normally distributed,with the mean score being 77.03?8.25,the average degree of difficulty being 0.778,and discrimination being 0.426.Conclusion The examination paper could make an assessment of students'command of the course,with moderate difficulty and reasonable score distribution.

Objective To investigate the modulation role of autophagy in radiation-induced cell death by detecting the response of src kinase activity and autophagy in HEK293 cells irradiated with different dose of α-particle.Methods HEK293 cells were irradiated by contral group (0 cGy) a low dose group (10 cGy) and high dose group (300 cGy) α-particles.Molecular probe 2',7'-dichlorofluorescin (DCFHDA) was used to detect the cell ROS.The src kinase activity and endogenous protein level of LC3Ⅰ/Ⅱ were monitored by Western Blot.Cell death rate of irradiated cells pretreated with autophagy inducer of rapamycin was tested by flow cytometry.Results Compared with control group,the ratio of LC3Ⅰ/Ⅱ decreased (t =4.07,P ＜ 0.05) and the percentage of cells with GFP-LC3 punctuate dots increased (t =12.29,P ＜0.05) under 10 cGy irradiation,indicating the induction of autophagy.On the contrary,the ratio of LC3Ⅰ/Ⅱ increased (t =2.93,P ＜ 0.05) and the GFP-LC3 morphology had no obvious change under 300 cGy irradiation.The cellular ROS level reached to the maximum value at 4 h postirradiation.Both 10 cGy and 300 cGy irradiation could elevate the ROS level (t =17.93,22.88,P ＜0.05),whereas the amplitude of elevation of 300 cGy irradiation was higher than that of 10 cGy irradiation (t =15.76,22.66,14.22,P ＜ 0.05).Compared with control group,the 419th site of tyrosine residue in src kinase manifested hyper-phosphorylation (t =5.66,P ＜0.05) under 10 cGy irradiation whereas it had hypo-phosphorylation under 300 cGy irradiation (t =4.67,P ＜ 0.05).Treatment of cells with DMSO could partly restore the impact on src kinase activity under high or low dose irradiation.Pre-treating the cells with autophagy inducer rapamycin could reduce cell death under 300 cGy irradiations (t =12.14,P ＜ 0.05).Conclusions High or low dose of α-particles irradiation could inhibit or activate src kinase and autophagy system,respectively.ROS mediated the response of src kinase activity and autophagy system induced by irradiation.Modulation of autophagy could desensitize cell responses to irradiation.