ObjectiveIn order to improve the survival of graft liver after liver transplantation, this study was designed to investigate whether intraportal injection of 150mg/kg N-acetylcysteine (NAC) in rats could reduce hepatic ischemia-reperfusion injury after 48 h of cold storage and 2 h of reperfusion. Methods Healthy male Wistar rats weighing 250-350g were used. The study consisted of three groups: control group (group Ⅰ) ;NAC-treated group(group Ⅱ). 1 ml of 5% dextrose (D5%) or 1 ml D5% containing 150mg/ kg NAC was injected into the superior mesenteric vein. 15 min after the injection of D5 % or NAC the liver was flushed with cold (4℃) Ringer' s solution through the portal vein . After perfusion, the liver was removed and kept in 100 ml UW solution at 4℃ for 48 h. In group Ⅲ animals were pretreated with buthionine sulfoximine (BSO) 2 h before intraportal injection of D5 % or NAC and liver harvesting. After cold storage, the livers were then perfused for 2 h by a closed circulating system. Aspartate transaminase (AST), alanine transaminase (ALT), and lactate dehydrogenase (LDH) activities in the perfusate were determined by reflectometry. Lactate and acid phosphatase activities were determined by enzymatic methods. ResultsAfter 48 h of cold storage and 2 h of reperfusion, livers from NAC-treated group produced larger amounts of bile than those in the control group, and released less LDH, AST, ALT and acid phosphatase, a marker of Kupffer cell injury in the perfusate. The protective effects of NAC against cold ischemia-reperfusion liver injury were maintained when animals were pretreated with BSO, a specific inhibitor of glutathione synthesis. ConclusionsThis study shows that intraportal administration of NAC in vivo significantly improves the initial function of the isolated rat liver. Our results also indicate that NAC inhibits the activation of Kupffer cells, which are the first source of reactive oxygen intermediates during reperfusion.

Rat liver mitochondria were exposed to various conentrations of halothane,enflurane, isoflurane and sevoflurane. Electron transfer rates from NADH and succinate to cytochrome C were measured by scanning dual wavelength spectrophotometer. Statistical analysis of the data suggested that halothane at clinical or higher than clinical concentrations markedly inhibited activities of NADH-Cyt,C reductase.in contrast,no decrease occurred in the activities of NADH dehydrogenase,NADH-coenzyme Q reductase and enzymatical system of succinate chain. Enflurane,isoflurane and sevoflurane had little effect on enzymatical system of mitochondrial electron transfer chain. These data indicate that halothane interfere with utilization of NADH-linked substrate by blocking electon transport from NADH to cytochrome C and it is probable that the locus of action is at Q binding protein(Qpn) or complex of Qpn and ubiquinone.

Objective In order to improve the survival of graft liver after liver transplantation, this study was designed to investigate whether intraportal injection of 150mg/kg N-acetylcysteine (NAC) in rats could reduce hepatic ischemia-reperfusion injury after 48 h of cold storage and 2 h of reperfusion.Methods Healthy male Wistar rats weighing 250-350g were used.The study consisted of three groups: control group (group Ⅰ);NAC-treated group(group Ⅱ).1 ml of 5% dextrose (D5%) or 1 ml D5% containing 150mg/kg NAC was injected into the superior mesenteric vein.15 min after the injection of D5% or NAC the liver was flushed with cold (4℃) Ringer's solution through the portal vein .After perfusion, the liver was removed and kept in 100 ml UW solution at 4℃ for 48 h.In group Ⅲ animals were pretreated with buthionine sulfoximine (BSO) 2 h before intraportal injection of D5% or NAC and liver harvesting.After cold storage, the livers were then perfused for 2 h by a closed circulating system.Aspartate transaminase (AST), alanine transaminase (ALT), and lactate dehydrogenase (LDH) activities in the perfusate were determined by reflectometry.Lactate and acid phosphatase activities were determined by enzymatic methods.Results After 48 h of cold storage and 2 h of reperfusion, livers from NAC-treated group produced larger amounts of bile than those in the control group, and released less LDH, AST, ALT and acid phosphatase, a marker of Kupffer cell injury in the perfusate.The protective effects of NAC against cold ischemia-reperfusion liver injury were maintained when animals were pretreated with BSO, a specific inhibitor of glutathione synthesis.Conclusions This study shows that intraportal administration of NAC in vivo significantly improves the initial function of the isolated rat liver.Our results also indicate that NAC inhibits the activation of Kupffer cells, which are the first source of reactive oxygen intermediates during reperfusion.

The essence of training for clinical postgraduates is comprehensive capacity,including clinical and scientific research capacity,and the demand for the former is relatively higher than the latter. By means of discussion on the source and the educational system for postgraduates,we try to train clinical anesthesiology postgraduates with high diathesis and meet the needs of clinical anesthesia.

Clinical practice is an important teaching stage for interns of anesthesiology in medical universities.We discuss advantages and disadvantages for different teaching modes in the course of clinical practice,aiming at choosing a better one to optimize practice quality and bringing up graduates with high diathesis.

Objective To establish a method for acute isolation of rat superior cervical ganglion (SCG) cells and identify the electrophysiological properties.Methods Sprague-Dawley rats of both sexes,aged 5-12 days,were decapitated.The SCGs were removed quickly,and the single SCG cell was enzymatically isolated from the SCGs.When the holding potential was - 60 mV,100 μmol/L acetylcholine was applied and the nicotinic acetylcholine receptor currents were recorded by whole-cell patch-clamp technique.When the holding potential was 760 mV,65 mmol/L KCl was applied and quantal release of catecholamines was detected by using carbon fiber electrodes.Results SCG cells with normal electrophysiological properties were isolated.Typical nicotinic acetylcholine receptor currents and quantal release of catecholamines were recorded successfully.Conclusion The cells suitable for patch-clamp experiments can be obtained by using the method for acute isolation of rat SCG cells.

Objective To observe how the ACC transmits nociceptive information and how it regulates spinal noceciption.Methods A total of 32 male SD rats were randomly divided into four groups:Sham group,CCI group,ACC group,and AP-5 group.After light-dark transition test, forced swimming test (FST),paw withdrawal mechanical threshold (PWMT),paw withdrawal ther-mal latency (PWTL)had been measured,the rats were finally anesthetized,then ACC and the spinal cord was rapidly removed,the expression of cAMP-response element binding protein (pCREB)and extracellular regulated protein kinases (pERK)were measured by Western blot.Results Compared with the sham group,the PWMT of the CCI rats were significantly decreased,rats spent less time in the light compartment and number of transition were decreased (P <0.01 ).The immobility time in FST were also significantly prolonged (P <0.01).After AP-5 injected in bilateral ACC 13 days after CCI operation,the PWMT of the CCI rats were significantly increased,rats spent more time in the light compartment and number of transition were increased (P <0.01).The immobility time in FST were also significantly shortened (P <0.01).Compared with sham group,the expression of pCREB, pERK increased significantly in ACC in CCI group (P <0.01).The expression of pCREB,pERK in spinal cord was increased in CCI group and decreased in AP-5 group (P <0.01 ).Conclusion ACC facilitate the spinal nociception in a descending mode.

Objective To evaluate the relationship between the mechanism of spinal monocyte chemoattractant protein-1 (MCP-1)-mediated maintenance of chronic pathological pain and synaptic transmission in spinal dorsal horns of rats.Methods Female Sprague-Dawley rats,aged 2-3 weeks after birth,weighing 150-210 g,were studied.The experiment was performed in 2 parts.Experiment Ⅰ Eighteen Sprague-Dawley rats were randomly divided into 2 groups (n =9 each) on 7 days after intrathecal catheters were inserted:phosphate buffer solution (PBS) group and MCP-1 group.PBS 10 μl was intrathecally injected in group PBS,and PBS 10 μ1 containing 100 ng MCP-1 was intrathecally injected in group MCP-1.The mechanical pain threshold was measured at 30 and 60 min before intrathecal injection,and 30,60,90,120,150 and 180 min and 1,2 and 3 days after intrathecal injection.Experiment Ⅱ The transverse spinal cord slices were prepared,and substantia gelatinosa neurons were selected for whole-cell patch-clamp recording.Electrophysiological recording was performed at 1 h of incubation with artificial cerebrospinal fluid (ACSF) and immediately after adding MCP-1:for excitatory synaptic transmission recording,MCP-1 (final concentration 100 nmol/L),N-methyl-D-aspartate (NMDA,final concentration 100 μmol/L) and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA,final concentration 20 μmol/L) were added to ACSF,and spontaneous excitatory postsynaptic currents (sEPSCs),AMPA receptors-mediated currents and NMDA receptors-mediated currents were recorded;for inhibitory synaptic transmission recording,MCP-1 (final concentration 100 nmol/L) and γ-aminobutyric acid (GABA,final concentration 1 mmol/L) were added to ACSF,and spontaneous inhibitory postsynaptic currents (sIPSCs) and GABA receptors-mediated currents were recorded.Results Compared with group PBS,the mechanical pain threshold was significantly decreased at 30 min-2 days after intrathecal injection in group MCP-1 (P＜0.01).Compared with those at 1 h of incubation with ACSF,the frequency and amplitude of sEPSCs were significantly increased,the amplitude of NMDA receptors-and AMPA receptors-mediated currents were increased,the frequency and amplitude of sIPSCs were decreased,and the amplitude of GABA receptors-mediated currents was decreased immediately after adding MCP-1 (P＜0.05).Conclusion MCP-1 enhances excitatory synaptic transmission through enhancing the function of NMDA and AMPA receptors in the posterior substantia gelatinosa neurons of the spinal cord;MCP-1 weakens inhibitory synaptic transmission through inhibiting GABA receptor function,which may be involved in MCP-l-mediated maintenance of chronic pathological pain in rats.

Objective To examine the analgesic effect of intrathecal (i.t.) adenovirus containing human beta-endorphin (?-EP) gene in a rat model of neuropathic pain produced by chronic constrictive injury (CCI) . Methods Thirty-six male SD rats weighing 210-260 g were randomly divided into 3 groups: (1) blank control group (n = 5); (2) sham-operated group (n = 5) ; (3) neuropathic pain group (n = 26) . The neuropathic pain group was further divided into 3 subgroups: Ad-NEP subgrouop (n = 9); Ad-GFP (the recombinant adenovirus containing green fluorescent protein) subgroup (n = 9) and normal saline (NS) subgroup (n = 8). The animals were anesthetized with intraperitoneal ketamine 100 mg?kg-1 and atropine 50 mg?kg-1. Neuropathic pain was produced by ligation of right sciatic nerve according to the technique described by Bennet and Xie. In sham-operated group the sciatic nerve was exposed but not ligated. In blank control group no operation was performed. Seven days after the surgery a PE-10 catheter was placed in the subarachnoid space at L5,6 according to the method of Milligan et al. Seven days after catheter placement 1?108 pfu Ad-NEP, Ad-GFP and 0.9% saline were injected i.t. via the catheter respectively. The paw-withdrawal latency to radiant heat was measured before surgery (T0,baseline) , the day of i.t. injection (T1) and 1 day (T2) , 1 w (T3), 2 w (T4), 3 w (T5), 4 w (T6) 5 w (T7) after i.t. injection. At one week after i.t. administration one animal in Ad-NEP subgroup and Ad-GFP subgroup was killed and the lumbar segment (L3-6) of the spinal cord was removed for immuno-histochemical examination. Naloxone 1 mg?kg-1 was given intraperitoneally in Ad-NEP subgroup (n = 8) and Ad-GFP subgroup (n = 8) at 10 days after i.t. injection. Pain threshold to thermal stimulation of the right paw was measured before (t0) and from 10-90 min after intraperitoneal naloxone injection at an interval of 10 min (t1-9). CSF samples were obtained at T1-7 for determination of CSF concentration of ?-EP using radio-immunological assay. Results The right paw-withdrawal latencies (PWLs) were significantly lower in Ad-GFP subgroup and NS subgroup than in blank control and sham-operated groups (P

Objective To compare the pharmacokinetic profile of propofol administered by target-controlled infusion (TCI) during anesthesia in patients with and without obstructive jaundice. Methods Twenty-four ASAⅠorⅡpatients aged 40-65 yrs weighing 50-75 kg undergoing elective surgery under general anesthesia were divided into 3 groups (n = 8 each) : group A control (serum total bilirubin 171.1?mol?L-1) . Each group received propofol by TCI using Graseby 3500 infusion pump, based on pharmacokinetic parameter set published by Marsh. The target plasma concentration of propofol was set at 3?g?ml-1 . TCI of propofol was started from the induction of anesthesia and maintained until the end of the surgery. Arterial blood samples were taken at 0.5, 1, 2, 4, 6, 8 min after TCI of propofol was started and every 15 min during maintenance of anesthesia and at 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 90, 120, 180, 240 and 300 min after TCI was terminated. Plasma concentrations of propofol were determined by high-performance liquid chromatography (HPLC) with fluorescence detector. NONMEM was used to analyze the pharmacokinetic parameters. Results The 3 groups were comparable with respect to sex ratio, age and body weight. The pharmacokinetic profile of propofol given by TCI was best described by three-compartment open pharmacokinetic model in the majority of patients and by two-compartment open pharmacokinetic model in a few patients. There were no significant differences in the pharmacokinetic profile of propofol among the 3 groups. Conclusion Obstructive jaundice does not affect the pharmacokinetics of propofol.