Objective To evaluate the efficacy of dexmedetomidine combined with sufentanil for patientcontrolled intravenous analgesia (PCIA) after caeserean section. Methods One hundred and twenty parturients aged 18-40 yr undergoing caeserean section under spinal-epidural anesthesia were randomly assigned to one of 3 groups( n=40 each):group Ⅰ , group Ⅱ and group Ⅲ . During operation as soon as the baby was bom a bolus of dexmedetomidine 0.5 μg/kg was given iv in Ⅱ and Ⅲ groups while in group Ⅰ normal saline (NS) was given instead. Ⅰ and Ⅱ groups received PCIA with sufentanil (background infusion 0.015 μg·kg-1·h-1;bolus dose 0.023 μg/kg;lockout interval 8 min). Group Ⅲ received PCIA with sufentanil + dexmedetomidine (background infusion sufentanil 0.015 μg·kg-1 ·h-1 + dexmedetomidine 0.045 μg·kg· h-1;bolus dose sufentanil 0.023 μg/kg + dexmedetomidine 0.07 μg/kg;lockout interval 8 min) . Pain threshold and pain tolerance threshold were measured before caeserean section and 1 h after bolus dose of dexmedetomidine or NS. VAS, OAA/S and satisfaction scores and sufentanil consumption were recorded at 4, 8 and 24 h after operation.Blood samples were obtained before anesthesia,1 h after bolus injection of dexmedetomidine, and 24 h after operation for determination of serumcortisol concentration. Results Pain threshold and pain tolerance threshold at 1 h after bolus injection of dexmedetomidine were significantly increased as compared with the baseline before anesthesia in Ⅱ and Ⅲ groups and were significantly higher in Ⅱ and Ⅲ groups than in group Ⅰ . VAS scores and the consumption of sufentanil were significantly lower while the satisfactory score was significantly higher in group Ⅲ than in Ⅰ and Ⅱ groups. Serum cortisol concentrations were significantly increased at 1 h after iv dexmedetomidine or NS injection as compared with the baseline before anesthesia in all 3 groups, but there was no significant difference in serum cortisol levels among the 3 groups. Conclusion Addition of dexmedetomidine to sufentanil for PCIA can significantly reduce the consumption of sufentanil and improve parturient's satisfaction.

Objective To compare the effects of labor epidural analgesia initiated in latent phase and active phase on parturients and neonates. Methods One hundred twenty nulliparous women at full term (single, head presentation, ASA Ⅰ or Ⅱ ) were randomly divided into 3 groups (n=40 each):control group(group C) ; PCEA initiated in latent phase group (cervical dilatation 0.5-3.0 cm) (group L) and PCEA initiated in active phase group (cervical dilatation＞3.0 cm) (group A). Epidural catheter was placed through L2,3 interspace. 0.1% ropivacaine with fentanyl 2 μg/ml was used for PCEA. A test dose of 5 ml was followed by a loading dose of 10 ml. PCEA device was programmed to allow a bolus of 6 ml with a 30 min lockout interval. The intensity of pain was measured with VAS (0=no pain, 10=worst pain) before analgesia, at 5, 10, 15 and 30 min after beginning of PCEA and cervical dilatation of 7-8 cm and 10 cm. Degree of motor block was assessed by lower extremity muscle strength (modified Bromage scale,0=no motor block, 3=inability to flex ankle joints).Plasma cortisol in maternal venous blood obtained before analgesia and at delivery of fetus and in umbilical cord blood and plasma ropivacaine concentrations in umbilical core blood were determined.The length of every stage, duration of analgesia,delivery mode, the amount of oxytocin used, maternal satisfaction, Apgar scores of the neonates and adverse effects were recorded. Results PCEA initiated in latent phase or active phase significantly reduced VAS score, the plasma cortisol level at delivery, the duration of 1st stage of labor, and the rate of cesarean section and increased the use of oxytocin in L and A groups as compared with group C, but there was no significant difference in the above variables between L and A groups. The duration of analgesia was shorter in group A than in group L. Conclusions Labor epidural analgesia initiated in latent phase or active phase can decrease the rate of cesarean section but does not prolong the duration of labor and is safe for the newborn.

Objective To investigate the effect of different time administration of parecoxib sodium on the postoperative analgesic efficacy in patients undergoing thoracic surgery. Methods This was a prospective,randomized, double-blind, placebo-controlled study. Sixty ASA Ⅰ orⅡ patients aged 17-83 yr undergoing pulmonary lobectomy were randomly allocated to one of 3 groups (n=20 each):A, B and C groups. Group A received normal saline 2 ml at 30 min before skin incision and the end of operation. Group B received iv parecoxib sodium 40 mg at 30 min before skin incision and normal saline 2 ml at 30 min before the end of operation. Group C received normal saline 2 ml at 30 min before skin incision and iv parecoxib sodium 40 mg at 30 min before the end of operation. All the patients received patient-controlled intravenous analgesia with morphine and VAS score was maintained≤3. The patients were followed up after operation.The morphine consumption, patients' global evaluation of the postoperative analgesia (0-100, 0=worst pain, 100=no pain), nausea and vomiting, body temperature , volume o chest drainage, hepatic, renal and blood coagulation function were recorded. Results Compared with group A, the morphine consumption was significantly reduced, the patient' s satisfaction score increased and body temperature decreased in B and C groups(P＜0.05 or 0.01). There was no significant difference in the morphine consumption, patient's satisfaction score and body temperature between B and C groups(P＞0.05). No significant difference was found in the parameters of hepatic, renal and blood coagulation function, volume of chest drainage and incidence of nausea and vomiting among the three groups(P＞0.05).Conclusion When postoperative analgesia is assisted with iv parecoxib sodium 40 mg given at 30 min before skin incision or at 30 min beforethe end of operation,the efficacy is similar,and both can improve the postoperative analgesic efficacy of morphine and reduce fever after operation in patients undergoing thoracic surgery.

Objective To investigate the feasibility of NR2B small interference RNA(NR2B siRNA)carried by water-soluble lipopolymer(WSLP)for treatment of neuropathic pain in rats.Methods One hundred healthy male SD rats weighing 180-200 g were randomly divided into 5 groups(n=20 each):normal control group (group C),sham operation group(group S),neuropathic pain group(group NP),group WSLP-NR2B siRNA (group W)and group WSLP-negative NR2B siRNA(group WN).Neuropathic pain was induced by partial ligation of sciatic nenre.WSLP-NR2B siRNA complex was formed by binding WSLP and NR2B siRNA.Normal saline.WSLP-NR2B siRNA complex and WSLP-negative NR2B siRNA 20μl were injected intrathecally after operation in NP,W and WN groups respectively.Mechanical withdrawal threshold(MWT)and thermal withdrawal duration (TWD)were measured before(baseline)and at 3,7,14 and 21 days after operation.Ten animals in each group were sacrificed on the 3rd day after operation and the lumbar segment(L4-6)of the dorsal root ganglia was removed for determination of the expression of NR2B mRNA and protein using RT-PCR and Western blot analysis.Results Sciatic nerve ligation significantly decreased MWT and prolonged TWD and increased NR2B mRNA and protein expression in group NP as compared with group C.WSLP-NR2B siRNA complex significantly reduced sciatic nerve ligation-induced hyperalgesia and decreased NR2B mRNA and protein expression in group W as compared with group NP.Conclusion WSLP not only mediates NR2B siRNA successfully and inhibits the expression of NR2B,but also reduces neuropathic pain in rats.

Objective To investigate the effect of tourniquet compression on axonal transport in sciatic nerve of rats.Methods Twenty-four 12-week old male SD rats weighing 250-300 g were randomly divided into 4groups according to the duration of tourniquet compression(n=6 each):1,2,4 and 12 h.The tourniquet was applied to the middle 1/3 of thigh.In each animal whether the left or right thigh was compressed was determined by a flip of coin.The tourniquet was released for 10 min after every hour of compression.A 3-cm segment of sciatic nerve was removed at the end of tourniquet compression(1.5 cm proximal and 1.5 cm distal to the site of compression).Immuno-histochemistry was used to measure the expression of insulin-like growth factor-1(IGF-1)in the sciatic nerve.The ratio of average optic density of the compressed sciatic nerve to that of control was used to estimate the degree of IGF-1 accumulation.The regression equation of the interaction between the duration of compression and accumulation of IGF-1 was analyzed.Results There was significant accumulation of IGF-1 in the sciatic nerve proximal to the compressed site.The accumulation increased with the duration of compression.There was no significant accumulation of IGF-1 in the sciatic nerve distal to the compressed site.The regression equation of the interaction between the duration of compression(X)and accumulation of IGF-1(Y)was Y=0.422X+0.887.Conclusion Tourniquet compression of sciatic nerve can inhibit axonal transport.The accumulation increases with the duration of compression.

Objective To investigate the effect of dexmedetomidine on norepinephrine(NE)release in midbrain periaqueductal gray(PAG)in a rat model of incisional pain.Methods Twenty-four male Wistar rats in which microdialvsis catheter was successfully placed in the ventrolateral region of PAG without complications were randomly divided into 4 groups(n=6 each):group control(group C);group incisional pain(group IP);group dexmetomidine(group D)and group dexmedetomidine+yohimbine(group DY).Incisional pain was induced by an incision made into the plantar surface of left hindpaw in IP,D,DY groups.Dexmedetomidine 30 μg/kg and dexmedetomidine 30 μg/kg+yohimbine 0.5 mg/kg were given intraperitoneally at 15 min before plantar incision in group D and group DY respectively.Mechanical paw withdrawal threshold(MWT)to von Frey filament stimulation was measured at 30 min before(baseline)and 1,2,3,4 h after operation in C,IP,D groups,and at 30 min before(baseline),and 1 h after operation in group DY.Dialysate samples were collected at 30 min before(baseline)and at evcry 30 min after operation for 4 h via cerebral microdialysis catheter for determination of the NE concentration in C,IP,D groups,and at 30 min before(baseline),30,60 min after operation in group DY.Results Incisional pain significantly decreased MWT and increased the NE concentration in dialysate in group IP.Dexmedetomidine premedication significantly inhibited mechanical hyperalgesia and attenuated incisional pain-induced increase in the NE concentration in dialysate in group D.Yohimbine counteracted effects of dexmedetomidine.Conclusion Dexmedetomidine has analgesic effect though inhibition of NE release from PAG.

Objective To construct rat TRESK gene recombinant adenovirus expression vector.Methods TRESK full-length cDNA was cloned from rat dorsal root ganglion cells and confirmed by RT-PCR and sequencing. pAd/CMV/V5-DEST-TRESK was then constructed under the control of CMV-promotor. DH5α colibacillus was translated and the positive recombinants were subsequently identified by PCR and DNA sequencing. 293T cells were cotransfected and packed to produce adenovirus. Results The titer of virus was tested using Hole-by-dilution titer method. The full length of TRESK from rat dorsal root ganglion cells is 781 bp. It was demonstrated that the DNA sequencing was completely consistent with TRESK sequencing of rat recorded in GeneBank. The PCR amplification of the pAd/CMV/V5-DEST-TRESK gDNA was matched with pAD-GFP blank vector as anticipated. The titer of the concentrated virus was 1.31×109 TU/ml. Conclusion Rat TRESK gene recombinant adenovirus vector is constructed successfully.

Objective To compare the changes in blood coagulation, fibrinolysis and endothelial damage in patients undergoing laparoscopic cholecystectomy with different durations of carbon dioxide pneumoperitoneum. Methods Sixty-four ASA Ⅰ orⅡpatients, aged 23-60 yr, weighing 45-82 kg, scheduled for elective laparoscopic cholecystectomy, were randomly divided into 3 groups according to the duration of pneumoperitoneum: duration of pneumoperitoneum ≤30 min group (group Ⅰ, n=21), 30 min ＜ duration of pneumoperitoneum ＜ 60 min (group Ⅱ, n=23) and duration of pneumoperitoneum≥ 60 min (group Ⅲ , n=20).The intra-abdominal pressure was maintained at 12-14 mm Hg. Venous blood samples were taken before surgery (baseline, T0 ),at the end of surgery(T1), and at 1, 2 and 3 d after surgery (T2-4) for determination of prothrombin time, activated partial thromboplastin time, concentrations of prothrombin fragment 1+2(F1+2), fibrinogen (Fib), tissue plasminogen activator and plasminogen activator inhibitor type-1 (PAI-1), and activities of antithrombin Ⅲ(AT-Ⅲ)and von Willebrand factor(vWF).Results Compared with groupⅠ , the vWF activity and PAI-1 concentration at T2 , concentrations of Fib, F1+2, PAI-1 and activity of vWF at T3 and concentrations of Fib and F1+2 at T4 were significantly increased, while the AT-IE activity at T3 was significantly decreased in group Ⅲ(P＜0.05) .Conclusion When the duration of pneumoperitoneum is short, no obvious changes in the blood coagulation, fibrinolysis and endothelial damage are observed postoperatively in patients undergoing laparoscopic cholecystectomy, and along with the prolongation of the duration of pneumoperitoneum, increased blood coagulation, reduced fibrinolysisand aggravated endothelial damage are observed postoperatively.

Objective To evaluate the effect of intraoperative mechanical ventilation on alveolar gas exchange in patients with type 2 diabetes mellitus.Methods Thirty ASA Ⅰor Ⅱpatients with type 2 diabetes mellitus aged 46-64 yr weighing 47-78 kg undergoing total gastrectomy under general anesthesia were divided into 2groups according to preoperative glycolated hemoglobin level(HbA1c)(n=15 each):group B HbA1c/Hb=6.6%-10.4%and group C HbA1c/Hb＞10.4%.Another 15 non-diabetic patients with comparable demographic data were included in this study as control group(group A).Radial artery and right internal jugular vein were cannulated.The patients were intubated after induction of anesthesia and mechanically ventilated(VT 8 ml/kg,RR 12-lected from artery before induction of anesthesia(To,baseline)and at 30,60,90 and 120 min of mechanical ventilation(T1-4)for blood gas analysis and determination of plasma SOD activity and MDA,'TNF-α,IL-6,IL-10 concentrations.PA-aDO2 was calculated.Results PA-aDO2 was significantly increased during mechanical ventilation at T1-4 as compared with the baseline at T0 in diabetic patients and were significantly higher than in non-diabetic patients.The plasma SOD activity was significantly decreased at T1-4 as compared with the baseline at T0 in diabetic patients and was significantly lower than in non-diabetic patients.While the plasma MDA,TNF-α,IL-6 and IL-10concentrations were significantly increased at T1-4 compared with the baseline at T0 in diabetic patients and were significantly higher than in non-diabetic patients.The PA-aDO2,plasma MDA,TNF-α,IL-6 and IL-10 concentrations were significantly higher and plasma SOD activity lower in gorup C than in group B.Conclusion Intraoperative mechanical ventilation can decrease alveolar gas exchange by inducing inflammatory response in patients with type 2 diabetes mellitus.The changes are correlated with severity of diabetes.

Objective To evaluate the efficacy of nalmefene antagonizing postoperative respiratory depression induced by opioids.Methods Two hundred and forty ASA Ⅰ orⅡpatients aged 18-64 yr with body weight fluctuating within 20% of the standard body weight were included in this multicenter,randomized,double-blind,positive drug-controlled study.Anesthesia was induced with etomidate 0.3 mg/kg and TCI of sufentanil(effect-site concentration 0.4.ng/ml).Tracheal intubation was facilitated with vecuronium 0.1 mg/kg or rocuronium 0.6mg/kg.The patients were mechanically ventilated.PETCO2 was maintained at 35-45 mm Hg.Anesthesia was maintained with sevoflurane+ sufentanil TCI(Ce=0.1-0.4 ng/ml).Patients undergoing neurosurgery and liver or kidney operation were excluded.The operation time was within 3 h.The residual effects of muscle relaxants were reversed after operation.The patients were randomly divided into 2 groups(n=120 each):group Ⅰneloxone andgroup Ⅱ nalmefene.Naloxone 0.1 mg or nalmefene 0.25 μg/kg was injected iv over 30 s and was repeated 5 min later if necessary until the respiratory rate＞10 bpm,PETCO2＜45 mm Hg and apnea time＜15 s.The total amount of naloxone was≤0.4 mg while that of nalmefene≤1 μg/kg.BP,HR,SpO2,PETCO2,respiratory rate and apnea time were recorded immediately before and at 2 and 5 min after haloxone/nalmefene administration and then every 5 min until 5 min after extubation.The recovery of spontaneous breathing within 30 min after naloxone/nalmefene administration,extubation time and Ramsay sedation score at 5 min after extubation were recorded.The patients were also observed for adverse reactions.Results Spontaneous breathing recovered within 30 min after naloxone/nalmefene administration in all patients in both groups.The extubation time was significantly shorter in nalmefene group than in naloxone group.There was no significant difference in Ramsay sedation score,BP,HR,SpO2 and incidence of adverse reactions between the 2 groups.Conclusion Nalmefene is better than naloxone in antagonizing opioid-induced postoperative respiratory depression.