Objective To investigate the effects of different doses of dexmedetomidine on the minimum alveolar concentration of sevoflurane for blunting responses to skin incision ( MACBAR ) in patients undergoing lower abdominal surgery. Methods Sixty ASA Ⅰ or Ⅱ patients, aged 25-55 yr, weighing 45-75 kg, undergoing electire lower abdominal surgery under general anesthesia, were randomly divided into 4 groups ( n = 15 each): control group (Do group) and 3 dexmedetomidine groups (D1, D2 and D3 groups). The patients were unpremedicated.Dexmedetomidine was not used in group D0. A loading dose of dexmedetomidine 0.1μg/kg was injected iv over 10 min, and then dexmedetomidine was infused at a rate of 0.4, 0.8 and 1.2 μg· kg- 1 · h - 1 for 30 min in groups D1-3 respectively. Anesthesia was induced with inhalation of 8 % sevoflurane. Laryngeal mask airway was inserted when BIS value decreased to 45-55. The patients were mechanically ventilated with inhalation of sevoflurane and a mixture of 50% nitrous oxide and 50% oxygen, and the fresh gas flow was set at 1 L/min. In D0-3 groups, the initial end-tidal concentrations of sevoflurane were 3.0%, 2.5%, 2.0% and 1.5% respectively. The patients' response to skin incision was described as effective if MR or MAP increased by ＜ 15%, or ineffective (MR or MAP increased by ≥ 15%). When the response was effective, the end-tidal concentration of sevoflurane was decreased in the next patient, when ineffective, increased, and the ratio between the two successive concentrations was 0.9.The MRCBAR of sevoflurane was determined by up-and-down method, and 95% confidence interval was calculated.Results The MRCBAR (95% confidence interval) of sevoflurane was 2.85% (2.44%-3.32%), 1.91%(1.61%-2.26%), 1.52% (1.31%-1.77%), and 1.34% (1.15%-1.57%)in D0-3 groups respectively. The MRCBAR of sevoflurane was significantly lower in D1-3 groups than in D0 group, and in D2 and D3 groups than in group D1 (P ＜0.05＝. There was no significant difference in MRCBAR of sevoflurane between D2 and D3 groups (P ＞0.05) .ConclusionContinuous infusion of dexmedetomidine at 0.4, 0.8 and 1.2 μg·kg-1 ·h-1 for 30 min results in a decrease in MACBAR of sevoflurane and enhances the inhibitory effect of sevoflurane on the stress response, and in a dose-dependent manner.

Objective To compare the diagnostic value of CT and diffusion-weighted imaging in extremity soft tissue tumors. Methods A total of 104 cases of extremity soft tissue tumors were examined with CT scanning and MRI. All cases were histologically proven. Then we compared the CT value of various types of tumors. The b values of diffusion were 0 and 500 s/mm2. The apparent diffusion coefficient (ADC) values of a large region with no hemorrhage, necrosis, scar tissue, or calcification representing the lesion were measured. ADC values of benign tumors, malignant tumors and normal muscles were compared. Results There were 68 cases of benign tumors and 36 cases of malignant tumors. The CT findings of 45 cases and the MRI findings of 87cases were in accordance with pathological examination. The diagnosis of 59 cases by CT and 17 cases by MRI were wrong. The CT features of soft tissue tumors showed the low density masses. The features of lipoma or cyst were typical on CT. There were large differences among the different types of tumors performance on T1WI and T2WI. The ADC values of the malignant tumors were significantly lower than those of benign lesion sand muscles (P < 0.01). There was no significant difference in ADC values between benign lesions and muscles. there was significant difference between the detection level of CT and MRI (P < 0.01). Conclusion CT can clearly show soft tissue tumor lesions and to clarify their relationship and the surrounding tissue, but can not accurately characterize. MRI diffusion-weighted imaging can better differentiate benign and malignant, and speculate the histological lesions sources. MRI detection level is significantly higher than CT and more consistent with a higher degree of pathology. Thus in the preoperative diagnosis of soft tissue tumors, diffusion-weighted imaging MRI should be preferred.

Objective To investigate the role of mitochondrial ATP-sensitive potassium(mito-KATP)channels in attenuation of ischemia-reperfusion(I/R)injury by lidocaine pretreatment in the isolated rat heart.Methods Adult female Wistar rats weighing 220-250 g were anesthetized with intraperitoneal 3% pentobarbital 35 mg/kg.Their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95%O2-5%CO2 at 37 ℃.Twenty-four isolated rat hearts with I/R injury were randomly divided into 3 groups(n = 8 each):group I/R,lidocaine group(group L)and lidocaine + glibenclamide group(group LG).After 10 min of equilibration,group C,L and LG received 20 min of perfusion with K-H solution,K-H solution containing lidocaine 2.5 mg/L and K-H solution containing lidocaine 2.5 mg/L + glibenclamide(a blocker of mito-KATP channels)10 μmol/L,respectively,then subjected to 30 min of ischemia followed by 60 min of reperfusion.HR,left ventricular developed pressure(LVDP),+ dp/dtmax and - dp/dtmax were recorded at the end of equilibration(T0)and at 15,30,45 and 60 min of reperfusion(T1-4).Coronary effluent was collected at T0 and T4 for determination of lactate dehydrogenase(LDH)and creatine kinase(CK)activities.Myocardial tissues were obtained from cardiac apex at T4 for determination of Na+ -K+ -ATPase and SOD activities and MDA and Ca2+ contents.Results Compared with group I/R,HR,LVDP,+ dp/dtmax and - dp/dtmax were significantly increased,CK and LHD activities were decreased,Na+ -K+-ATPase and SOD activities were increased,and MDA and Ca2+ contents were decreased in group L(P ＜0.05).Compared with group L,HR,LVDP,+ dp/dtmax and -dp/dtmax were significantly decreased,CK and LHD activities were increased,Na+ -K+ -ATPase and SOD activities were decreased,and MDA and Ca2+ contents were increased in group LG(P＜0.05).Conclusion The mechanism by which lidocaine pretreatment attenuates I/R injury to the isolated rat heart is related to mito-KATP channel opening.

Objective To investigate the effect of STH-2 cardioplegic solution containing levosimendan on ischemia-reperfusion (I/R) injury in isolated rat hearts. Methods Thirty-two male Wistar rats weighing 250-300 gwere anesthetized with intraperitoneal 3% pentobarbital 30 mg/kg. The hearts were rapidly excised and perfused with oxygenated (95% O2-5% CO2) K-H solution for 30 min in a Langendorff apparatus and then divided into 4groups (n = 8 each) according to the composition of cardioplegic solution: group Ⅰ control (group C) was perfused with STH-2 cardioplegic solution; group Ⅱ , Ⅲ and Ⅳ were peffused with STH-2 cardioplegic solution containing levosimendan 0.03 μmol/L (L1), 0.3 μmol/L (L2) and levosimendan 0.3 μmol/L + glibenclamide 10 μmol/L (L2+ G) respectively. The isolated hearts were first perfused with different cardioplegic solutions for 2 h and then with K-H solution for 30 min. The coronary effluent was collected before ischemia (baseline) and at 10, 20 and 30 min of reperfusion for measurement of creatine kinase (CK) and lactate dehydrogenase (LDH)activities. Myocardial specimens were obtained from apex at 30 min of reperfusion for determination of myocardial ATP and MDA contents and SOD activity. Results Perfusion with STH-2 cardioplegic solution significantly increased CK and LDH activities and MDA content, and significantly decreased SOD activity. Levosinendan 0.03or 0.3 μmol/L significantly attenuated the cardioplegia-induced increase in LDH,CK and SOD activities and MDA content. The protective effects of levosimendan on myocardium against I/R injury were reversed by glibenclamide to some extent. Conclusion Levosimendan can protect myocardium from I/R injury in a dose-dependent manner by opening KATP channel.

BACKGROUND:Problems regarding the prosthesis in the horizontal plane and the rotation of the femur and tibia prosthesis on line are relatively weak. The distal femoral rotation axis is mainly the transepicondylar axis. Due to patient differences as wel as anatomy and intraoperative display, it is difficult to accurately locate the axis in the process of knee arthroplasty. OBJECTIVE:To investigate application of magnetic resonance technique in determining the axis of rotation of the distal femur, to provide reference and basis for femoral rotational alignment during total knee arthroplasty. METHODS:Data of 122 cases without knee joint disease, who were diagnosed and treated in the Department of Orthopedics of Nanyang City Center Hospital from September 2014 to October 2015, were analyzed. Magnetic resonance technique was used to measure femoral epicondyle axes (STEA), femoral epicondyle axes (CTEA), the anteroposterior axis (APL) and femoral shaft (PCL). Simultaneously, magnetic resonance technique was utilized to measure femoral ankle angle (PCA), ankle twist angle (CTA), axis vertical line and ankle axis angle (PAPA). Each data were tested three times, and the average value was calculatd. We analyzed the method of magnetic resonance technique to determine reference axis of distal femoral rotation. RESULTS ANDCONCLUSION: (1) Accuracy of the angle close to surgical transepicondylar axis: 3° PCL> CTEA > APL verticalline. (2) No significant difference in PCA was detected in two sets of measurements (P> 0.05). CTA and PAPA parameters in the first measurement by magnetic resonance imaging diagnosis were significantly lower than the second measurement (P< 0.05). (3) Results indicate that magnetic resonance technology provides ideal reference for distal femoral rotation, can accurately measure the CTA, PCA, PAPA andother indicators. It is a more reliable determination method and can be used in scientific determination of femoral rotational alignment reference axis in total knee arthroplasty. Except STEA, the accuracy of 3° PCL is highest.

Objective Comparing the effects of ultrasound with nerve stimulation guided obtu-rator nerve block(ONB)with simple nerve stimulation guided ONB for transurethral resection of blad-der tumor(TURBT),so as to realize the validity and advantages of ultrasound with nerve stimulation guided ONB.Methods Sixty ASA Ⅰ or Ⅱ,male or female,age 39-77 years old,BMI 1 9-30 kg/m2 patients undergoing elective TURBT were randomly divided into two groups,nerve stimulation group (group S)and ultrasound and nerve stimulation group (group US).Success rate of the first puncture, visual analog scale (VAS)pain score,insertion-adductor contraction interval (ICI),puncture times corresponding to ICI,adductor strength,incidence of complications and validity were observed during and after ONB.Results There was no significant difference of the general validity,adductor strength and complication incidence between the two groups.The success rate of the first puncture was signifi-cantly higher in group US than that in group S (P < 0.01).VAS pain score,ICI and puncture times were significantly lower in group US than those in group S (P < 0.05).Conclusion Compared with simple nerve stimulation guided ONB,ultrasound with nerve stimulation guidance showed less punc-ture time,more accurate positioning and more comfort.

Objective To investigate the relationship between the mechanism underlying hydrogeninduced reduction of sepsis-associated encephalopathy (SAE) and phenotypic transformation of hippocampal microglias in mice.Methods Eighty-eight adult male ICR mice,aged 6-8 weeks,weighing 20-25 g,were divided into 4 groups (n =22 each) using a random number table method:sham operation group (group Sham),sham operation plus hydrogen group (group Sham+H2),SAE group and SAE plus hydrogen group (group SAE + H2).Sepsis was induced by cecal ligation and puncture (CLP) in anesthetized mice.Sham and Sham+H2 groups only underwent simple laparotomy.Sham+H2 and SAE+H2 groups inhaled air containing 2％ hydrogen for 1 h starting from 1 and 6 h after CLP,respectively.Mice were sacrificed at 24 h after CLP,and hippocampi were isolated for determination of the levels of tumor necrosis factor (TNF-α),interleukin-6 (IL-6),transforming growth factor-β (TGF-β) and IL-10 (by enzyme-linked immunosorbent assay) and expression of inducible nitric oxide synthase (iNOS) and argininase-1 (Arg-1) (by Western blot).Morris water maze test was performed on 10 mice in each group at days 4-8 after CLP.PResults Compared with group Sham,the levels of TNF-α,IL-6,TGF-β and IL-10 were significantly increased,the expression of iNOS and Arg-1 was up-regulated,the escape latency was prolonged,and the rate of time spent in the target quadrant and the number of crossing the original platform were reduced in SAE and SAE+H2 groups (P＜0.05).Compared with group SAE,the levels of TNF-α and IL-6 were significantly decreased,the expression of iNOS was down-regulated,the expression of TGF-β,IL-10 and Arg-1 was up-regulated,the escape latency was shortened,and the rate of time spent in the target quadrant and the number of crossing the original platform were increased in group SAE+H2 (P＜0.05).Conclusion Hydrogen can promote phenotypic transformation of hippocampal microglias from M1 to M2 and reduce SAE in mice.