There is evidence that onset time and potency of the non-depolarizing neuromuscular blocking agents are related. The relationship between onset time and the rate of recovery has been less well studied. In this experiment, the myodynamie response of adductor pollicis to single electric stimulation of wrist ulnar nerve, served as the parameter of neuromuscular blockade, and with the isolated forearm technique being used, the onset and offset times of vecuronium, pancuronium, mivacuronium or doxacurium were recorded in four adult healthy volunteers respectively. The results indicated that there was a positive correlation between onset and offset times (r=0.958, P

Objective To investigate the changes in cerebral cAMP and PKA levels during development of acute opioid tolerance induced by remifentanil and to determine whether post-receptor cAMP/PKA signaling pathway is involved in the process. Methods Fifty-six male Kunming mice weighing 25-35 g were randomly divided into 5 groups: group Ⅰ control (C) (n=8); group Ⅱ received morphine infused intraperitoneally (IP) at 0.6 μg'kg-1·min-1 for 120min(M) (n=8); group Ⅲ,Ⅳ,Ⅴ received remifentnil infused IP at 0.4, 0.8 and 1.6 μg·kg-1·min-1 for 120 min(R1=8, R2n=8; R3 n=24).Control group received IP infusion of normal saline. Tail-flick test was performed td measure the response of animals to a thermal nociceptive stimulus before IP infusion, at 30, 60, 90 and 120 min after beginning of IP infusion and at 15, 30, 45 and 60 min after termination of IP infusion. Eight animals were decapitated at 60 min after termination of IP infusion in all 5 groups and the other 16 animals in group R3 were decapitated at 30 and 45 min after termination of IP infusion (n=8 each) for determination of intracellular contents of cAMP and activities of PKA in cerebral cortex and inferior colliculus-striatum by ELISA or radioactive isotope [32p,] ATP-catalyzing assay. Results The tail-flick latency was significantly prolonged during IP infusion as compared with the baseline before infusion in group M, R1 , R2 and R3 but became significantly shorter at 30 and 45 min after infusion than the baseline values in group R1, R2 and R3indicating hyperalgesia after remifentauil infusion. The cerebral contents of cAMP and PKA activities at 60 min after termination of infusion were comparable or decreased in group M, R1, R2 and R3 as compared with group C. There was no significant difference in cerebral cAMP contents and PKA activities at 30, 60 and 45 min after IP remifentanil infusion in group R3. Conclusion Remifentanil can induce acute hyperalgesic effect on mice, and there is no up-regulation of post-receptor cAMP/PKA signaling pathway in the acute opioid tolerance, which is not similar to that chronic opioid tolerance.

Objective To investigate the effects of midazolam on extracellular signal-regulated kinase 1 (ERK1),ERK2 and cyclic AMP response element binding protein (CREB) phosphorylation in hippocampal in rats.Methods Eighty male SD rats weighing 250-300 g were randomly divided into 2 groups ( n = 40) : group control (group C) and group midazolam (group M).The animals underwent a continuous multi-trial inhibitory avoidance training .The times of trial needed for each animal to attain the learning criterion ( 100 s) were recorded.Each animal was given intraperitoneal midazolam 3 mg/kg or normal saline 2 ml/kg at 15 min before training.The memory retention was tested at 0.5,1,2 and 24 h (n = 8,at each time point)after the training session and the memory latency was recorded.The animals were sacrificed 15 min after administration (T0) and after the memory testing (T1-4) and hippocampns was obtained for determination of phosphorylated ERK1 (p-ERK1),p-ERK2 and p-CREB expression.Results Compared with group C,the times of trial to attain the learning criterion were significantly increased,memory latency shortened at T2-4,ERK1 phosphorylation decreased at T0,3.4 while ERK2 and CREB phosphorylation decreased at T0-4.Conclusion Midazolam can inhibit ERK1,ERK2 and CREB phosphorylation in hippocampal in rats.

Objective To investigate the effects of dexmedetomidine on the outcome in rats with sepsis. Methods Male SD rats, aged 10-14 weeks, weighing 260-390 g, were used in this study. Sepsis was induced by cecal ligation and puncture (CLP). Ninety rats of successful sepsis model were randomly divided into 3 groups ( n = 30 each) : control group (group C), midasolam group (group M) and dexmedetomidine group (group D). In group C, M and D, normal saline at a rate of 1 ml/h, midazolam at a rate of 0.6 mg·kg-1·h-1 and dexmedetomidine at a rate of 5 μg·kg-1·h-1 were infused iv for 8 h after operation respectively. Ten rats of each group were selected for observation of the survival condition during 24 h after operation. Another 10 rats of each group were selected and blood samples were taken from carotid artery before operation and at 2, 4 and 5 h after operation for measurement of plasma concentrations of TNF-α and IL-6 by ELISA. The remaining 10 rats of each group were selected at 8 h after operation for determination of the renal function. The rats still alive after the determination of cytokines and renal function were killed and spleen tissues were taken for determination of the expression of caspase-3 and ubiquitin by Western blot. Results Compared with group C, the plasma concentration of TNF-α and fractional excretion of sodium (FENa+) were significantly decreased, caspase-3 expression in spleen tissues was down-regulated and abiquitin expression in spleen tissues was up-regulated in group M and D ( P < 0.05), while there were no significant differences in plasma concentration of IL-6 and creatinine clearance rate (Ccr) at 8 h after operation between group M and C and between group D and C ( P > 0.05). The plasma concentration of TNF-α was significantly lower in group D than in group M ( P < 0.05), while there were no significant differences in plasma concentration of IL-6, FE Na+ , Ccr and expression of caspase-3 and ubiquitin in splen tissues between group D and M ( P>0.05). The survival rates during 24 h after operation were 10%, 80% and 90% in group C, M and D respectively. The survival rates during 24 h after operation were signifrcantly higher in group M and D than in group C ( P > 0.05). Conclusion Dexmedetomidine can raise the survival rate during sepsis.

Objective To study the sedation efficacy of propofol combined with midazolam and /or fentanyl in fibreoptic choledochoscope. Methods Ninty outpatients were randomly divided into three groups. Group PF (n=31)was given fentanyl 0. 05 m.g plus propofol 1 mg/kg intravenously, group PM (n=29) midazolam 2 mg plus propofol 1 mg/kg, and group PMF(n=30) fentanyl 0. 05 mg, midazolam 2 mg and propofol 1 mg/kg. Propofol 20 mg was used when needed. HR,MAP,SpO_2,sedation scores and amnesia were recorded. Results All patients were awakened in 20 minutes after procedures. The recovery time was shorter in group PF than that in the other two groups. There were 21(67. 70%) patients in group PF, who were aware of surgery. Fifteen(48. 4%) patients were satisfied in group PF. Conclusion Propofol combined with midazolam and /or fentanyl in fibreoptic choledochoscope has better sedation without any obvious side effects.

Objective To evaluate the influence of epidural block on blood coagulation and rhedogy in patients undergoing esophagectomy or lobectomy. Methods Twenty-two ASA Ⅰ-Ⅱ patients (14 male, 8 female) aged 40-65 yr undergoing esophagectomy or lobectomy were randomized to receive either combined general-epidural anesthesia (GEA group , n = 11) or general anesthesia (GA group, n = 11). The patients were premedicated with intramuscular pethidine 50 mg, promethazine 25 mg and scopolamine 0.3 mg. In GEA group epidural catheter was placed at T9-10 interspace before general anesthesia. A test dose of 4 ml 2% lidocaine was given. When correct positioning of the epidural catheter was confirmed, general anesthesia was induced with propofol 1.5-2.0 mg? kg-1 , fentanyl 2?g?kg-1 and rocuronium 0.6 mg? kg-1 , after placement of double- lumen endobronchial tube the patients were mechanically ventilated (VT 10 ml?kg-1 , RR 12 bpm, I: E = 1:2). Anesthesia was maintained with isoflurane inhalation and intermittent i. v. boluses of vecuronium. A mixture of 2 % lidocaine and 0.33% dicaine (1:1) was continuously infused at a rate of 4-6 ml?h-1 during operation. After operation PCEA was commenced with 0.12% ropivacaine and morphine 80 ?g?ml-1 (background infusion 4 ml?h-1 , bolus dose 2 ml, lockout interval 6 min) . In GA group the patients received the same general anesthesia technique. Postoperatively the patients were placed on PCIA with morphine 0.5 mg?ml-1 (background infusion 1 ml?h-1 , bolus dose 2 ml, lockout interval 6 min) Pain intensity was measured using VAS (0-10). Blood samples were taken before induction of anesthesia (T0, baseline), 1 and 3 h after skin incision (T1 , T2 ) and on the morning of 1st and 3rd postoperative day (T3 , T4 ) . Blood samples were tested immediately in a thromboelastograph (TEG) coagulation analyzer. Usual clotting tests (PT, APTT, platelet count, Hb, Hct), fibrinolysis tests (t-PA, PAI-A) and rheology tests were performed at the same time. Results PT and APTT were significantly prolonged during and after operation (T2,T3 ) as compared with the baseline values in both groups (P

Objective The aim of this prospective randomized study was to compare the effects of remifentanil (R) and fentanyl (F) given by target-controlled infusion (TCI) on the Cp50 of TCI propofol for loss of consciousness ( LOC ) . Methods Sixty-four ASA 1 or II patients aged 20-55 yr undergoing elective cholecystectomy or mastectomy under general anesthesia were enrolled in this study. Their BMI ranged from 18-30 kg?m-2. The patients were randomly allocated to one of four groups with 16 patients in each group: (1) propofol alone (P), (2) P + remifentanil (Cp = 4 ?g?L-1 ) (R4), (3) P + remifentanil (Cp = 7 ?g?L 1 ) (R7) and (4) P + fentanyl (Cp = 4?g?L-1 ) (F). The patients were unpremeditated. Anesthesia was induced with remifentanil or fentanyl and propofol both given by TCI. The plasma concentration (Cp) of remifentanil and fentanyl were fixed in each group. The Cp50 of propofol for LOC was determined by up-and-down sequential trial. Cp of propofol was set at 1.25, 1.50, 1.80, 2.16, 2.59, 3.11, 3.73 and 4.48 mg?L-1 . If a patient did not go to sleep at a certain Cp of propofol, the next patient was tested at a higher concentration conversely if the patient went to sleep a lower concentration was tested in the next patient. The BIS values and hemodynamic changes were recorded before induction and at LOC (no response to verbal command and loss of eyelash reflex). The TCI pump was controlled by pharmacokinetic models developed by Marsh (propofol) Minto ( remifentanil) and Shafer ( fentanyl) . Results The Cp of propofol for LOC in group P was 3.48 mg ? L-1 , significandy higher than that in group F (2.31 mg ? L -1 ), group R4 (2.11 mg?L-1) and group R7 (1.76mg?L-1 ) (P

Objective To determine the effective target plasma concentration required to prevent tracheal intubation in 50% of patients (Cp50) anesthetized with propofol by TCI.Methods Twenty ASA Ⅰ or Ⅱ patients aged 18-45 yrs with body mass index

Objective: To investigate the changes of gastric intramucosal pH(pHi)and the association with hemody namics and oxygen utilization during cardiopulmonary bypass (CPB). Method: Adults (n=15)free of hepatic, pulmonary,and renal diseases undergoing nonemergent heart surgery,were selected. After induction of general anesthesia and endotracheal intubation,a tonometer nasogastric tube was positioned in the stomach to determine the intramucosal pH. Hemodynamics and oxygen utilization data and phi were measured at four times:30 minutes after induction of anesthesia; 15 minutes after termination of cardiopulmonary bypass; at the terminal of the surgery;and 1 day after the surgery. Result: Cardiac index significantly increased(P

Objective: To study the effects of the different doses of midazolam in fibreoptic gastroscopy on sedation, respiratory and circulatory function. Method: One hundred and four outpatients undergoing fibreoptic gastroscopy were randomly divided into four groups. The control group(N)was not given drugs, the other groups were intravenously given midazolam 0.07mg/kg(MS),0.05mg/kg(M),diazepam 10mg(D)respectively. The sedative scores, symptom, amnesia,HR,MAP and blood gases were observed. Result: The sedative scores of MS,M and D groups were much better than that of control group. There were significant differences in sedative scores,amnesia and sedative period between MS group and D group or M group. MAP decreased one minute after administering the drugs in MS,D and M groups significantly. The results of blood gases analysis of all groups were in normal ranges. Conclusion: Midazolam 0.07mg/kg can produce safe and effective sedation for fibreoptic gastroscopy.