Objective To evaluate the feasibility of using corrected body weight to set the tide volume (VT) for mechanical ventilation during general anesthesia in obese patients.Methods Sixty ASA physical status Ⅰ or Ⅱ obese patients,with a body mass index of 28-44 kg/m2,scheduled for elective extremity surgery under general anesthesia,were randomly divided into 3 groups (n =20 each):VT based on actual body weight group (group A),VT based on ideal body weight group (group Ⅰ),and VT based on corrected body weight group (group C).The pulmonary function of all patients was normal.The patients were endotracheally intubated and mechanically ventilated after induction of anesthesia.According to the corresponding body weight,the initial VT was set based on 8 ml/kg in each group (RR 15 bpm,I ∶ E =1 ∶ 2,FiO2 =100％).At 10 min after start of mechanical ventilation,peak airway pressure (Ppeak),airway plateau pressure (Pplat),airwayresistance (Raw) were recorded.Arterial blood samples were collected at 30 min of mechanical ventilation for blood gas analysis and PaO2,PaCO2 and the patients requiring readjustment of VT (PaCO2 ＞ 45 mm Hg or ＜ 35 mm Hg) were also recorded.Results Compared with group A,PaCO2 was significantly increased and Ppeak,Pplat and Raw were decreased in I and C groups (P ＜ 0.01).PaCO2 was significantly lower and Ppeak,Pplat and Raw were higher in group C than in group Ⅰ(P ＜ 0.01 or 0.05).There were no patients requiring readjustment of VT in group C,however,95％ patients required readjustment of V+ in group A and 80％ in group B.The percentage of patients requiring readjustment of VT was significantly higher in A and B groups than in group C (P ＜ 0.01).Conclusion Corrected body weight based on 8 ml/kg can be used to set the Vr for mechanical ventilation during general anesthesia in obese patients with normal pulmonary function.

Objective To evaluate the effect of dexmedetomidine administered locally on the median effective concentration ( EC50 ) of ropivacaine for paravertebral nerve block ( PVNB) . Methods Forty?eight ASA physical status Ⅰ or Ⅱ female patients, aged 20-64 yr, with body mass index<24 kg∕m2 , scheduled for elective unilateral segmental mastectomy under PVNB, were randomly divided into 2 groups ( n=24 each) using a random number table: ropivacaine group ( group R) and ropivacaine mixed with dexmedetomidine group ( group RD) . PVNB was performed at T4 on the operated side guided by ultrasound and nerve stimulator. Ropivacaine 20 ml and a mixture of ropivacaine and 20 μg dexmedetomidine 20 ml were injected locally in group R and group RD, respectively. The concentration of ropivacaine was determined by up?and?down sequential allocation. The initial ropivacaine concentration was set at 0. 35%, and the ratio between the two successive concentrations was 1. 2. The EC50 and 95%confidence interval of ropivacaine were calculated using Dixon?Massey method. Results The EC50 ( 95%confidence interval) of ropivacaine was 0.27% (0.23%-0.30%) and 0.22% (0.18%-0.25%) in group R and group RD, respectively. Compared with group R, the EC50 of ropivacaine was significantly decreased by 19% in group RD. Conclusion Small dose of dexmedetomidine administered locally can significantly enhance the efficacy of PVNB with ropivacaine.

Objective To report outcomes of patients with PSA ≥ 30 μg/L with initial negative transperineal template-guided saturation biopsy (TTSB). Methods From 2003 to 2010,a total of 1824 patients underwent transperineal saturation biopsies with the prostate template at the Peking Union Medical College Hospital.44 of them had initial negative biopsy with PSA ≥ 30 μg/L were reviewed in this study.The mean age was 68 years old (range,51 to 80).The mean biopsy cores were 28.7 (range,11 to 44).The median PSA level was 40 μg/L (range,30 to 128),and the median prostate volume was 73 ml (range,30 to 190).They were divided into four groups:TURP group,chronic prostatitis group,repeat biopsy group and miscellaneous group. Results Patients were followed up for a mean of 49 months (range,12 to 91).All patients of TURP group (15 cases) were identified as prostatic hyperplasia by postoperative pathology.2 of them had a second TTSB for PSA ＞ 10 μg/L after TURP,which were negative.5 patients of chronic prostatitis group had a declining PSA level after antibiotic therapy for 3 to 4 weeks.One patient took a second biopsy,which was identified as prostatitis.All patients of repeat biopsy group (18 cases) showed no significant decrease in PSA level during follow-up and undertook biopsies 2 to 4 times,6 of which were proved to be prostate cancer.All patients of the miscellaneous group (6 cases) had a declining PSA and didn't take a second biopsy. Conclusions Close follow-up and regular PSA testing for patients who had a high PSA level with initial negative biopsy would be help to avoid both false negative of prostate cancer and unnecessary biopsy.

Objective To study the MRI features of primary central nervous system lymphoma (PCNSL)to improve its diagnosis. Methods The MRI data of 1 3 patients with PCNSL confirmed by biopsy or surgical pathology were analyzed retrospectively.All patients underwent nonenhanced and contrast-enhanced MRI examinations.Results Multiple lesions in 8 cases and solitary one in 5 cases were found.Five leisons (38.5%)were located in the cerebral hemispheres.Eight(61.5%)were located in deep structures of the brain including periventricular white matter,basal ganglia,thalami and corpus callosum,6 (46.2%)of whom involved in the ependyma including 1 involved in the ependyma of the 4 th ventricle.One leison(7.7%)was located in the cerebellar hemisphere.The tumor showed isointense or mildly hypointense signal on T1WI,mildly hyperintense signal on T2WI and hyperintense signal on DWI.Mild to moderate perilesional edema was noted.The tumors in 13 cases showed remarkable homogeneous enhancement after the contrast agent was injected with the signs of characteristic notch,butterfly and satellite.Focal necrosis occurred in 1 lesions.Conclusion PCNSL shouldbe first considered when a lesion located in the deep central structeres of the brain,multiple and involve ependymal membrane,showed isointensity on T1WI and T2WI,highintensity on DWI in tumoral parenchyma demonstrated,significantly enhancement in the solid part of the tumor.

Objective: To determine whether microtubule-associated protein 2 (MAP2) and microtubule-associated protein 1B (MAP1B) could be prognostic biomarkers for patients with pancreatic neuroendocrine tumors (PNETs). Methods:With immunohisto-chemical staining, the expressions of MAP2 and MAP1B were examined in 193 and 120 primary tumors and peritumoral tissues, re-spectively. Then, the relationship between the expression of each protein and clinicopathological characteristics, including prognosis was analyzed. Results:MAP2 and MAP1B were expressed in 88 of 193 (45.6%) and 77 of 120 (64.2%) tumors, respectively. The expres-sion of MAP2 was significantly associated with the favorable overall survival of patients with PNETs (P=0.012). Moreover, MAP2 expres-sion was associated with the improved overall survival in a subset of patients with stageⅡand stageⅢtumors (P=0.017). The MAP1B expression did not correlate with other clinicopathological features and prognosis. Conclusion:MAP2 could be a novel, independent prognostcbiomarker for PNETs.