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ObjectiveTo investigate the role of heme oxygenase-1 (HO-1 ) in process of sevoflurane preconditioning attenuating hypoxia-reoxygenation (H/R) injury in cultured neonatal rat cardiomyocytes.Methods Primary cultured neonatal rat cardiomyocytes were randomly divided into four groups ( n ＝ 25 each):control group (group C),group H/R,sevoflurane preconditioning group(group S + H/R),and HO-1 inhibitor zinc protoporphyria (ZnPP) and sevoflurane preconditioning group(group ZnPP + S + H/R).In group H/R,the cardiomyocytes were exposed to 2 hours of hypoxia,followed by 1 hour of reoxygenation.Group S+ H/R received 2.5％ sevoflurane preconditioning for 20 minutes followed by 10 minutes of wash-out before H/R.ZnPP was added to the culture medium with final concentrations of 3 μMol/L 1 hour before sevoflurane preconditioning and H/R in group ZnPP +S + H/R.HO- 1 expression,apoptosis rate,concentration of free calcium ( [ Ca2 + ] i),mitochondrial membrane permeability transition pore (PTP),cytoohrome C ( Cyto C) expression and activities of lactate dehydrogenase (LDH) and creatine kinase (CK) in culture supernatant were detected after reoxygenation.ResultsCompared with group C,the expression of HO-1 and cytoplasmic Cyto C of cardiomyocytes were up-regulated,mitochondrial Cyto C was down-regulated,while the [Ca2+ ]i,opening degree of PIP,apoptosis rate and activities of LDH and CK in culture supernatant were increased in group H/R.Compared with group H/R,the expression of HO-1 and mitochondrial Cyto C of cardiomyocytes were up-regulated,cytoplasmic Cyto C was down-regulated,while the [Ca2+ ] i,opening degree of PTP,apoptosis rate and activities of LDH and CK in culture supernatant were decreased in group S + H/R.Compared with group S + H/R,the expression of HO-1 and mitochondrial Cyto C of cardiomyocytes were down-regulated,cytoplasmic Cyto C was up-regulated,while the [Ca2+ ]i,opening degree of PTP,apoptosis rate and activities of LDH and CK in culture supematant were increased in group ZnPP + S + H/R.ConclusionThe up-regulation of HO-1 is involved in the process of sevoflurane preconditioning attenuating hypoxia-reoxygenation injury in cultured neonatal rat cardiomyocytes.
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Objective To evaluate the effect of morphine on synaptic long-term potentiation (LTP) in the spinal dorsal horn evoked by electric stimulation of sciatic nerve in rats. Methods Twenty-seven healthy male SD rats aged 60-90 d weighing 180-200 g were randomly divided into 4 groups: group Ⅰ control (group C, n=7), group Ⅱ morphine (group M, n=7), group Ⅲ naloxone (group N, n=6), and group Ⅳ morphine + naloxone (group MN, n=7). The animals were anesthetized with intraperitoneal 10% urethane 1 g/kg, intubated and then mechanically ventilated. The bipolar insulated stainless steel recording electrode (impedance 0.5-1 MΩ, diameter 0.1 mm) was inserted into the left side of the spinal dorsal horn at T13-L1 to stimulate the left side of the sciatic nerve. Single square pulses (15 V, 0.5 ms, 1/60 Hz for 30 min) was applied to evoke spinal field potentials. Normal saline 10 μl, morphine 10 μl (15 μg/μl), naloxone 10 μl (2.5 μg/μl), and the mixture 10 μl of naloxone 5 μl (2.5 μg/μl) and morphine 5 μl (15 μg/μl) was gradually instilled over 2 rain in the 4 groups respectively. Five minutes later, high-frequency and intensity tetanic stimulation (30-40 V, 0.5 ms, 100 Hz, given in 4 trains of 1-s duration at 10-s intervals) was used to induce LTP. Then single square stimuli (15 V, 5 ms, 1/60 Hz) were applied to the sciatic nerve for 210 min. The amplitude and latency period of the field potential were recorded 30 min before tetanic stimulation, and 0-30, 35-60, 65-120 and 125-210 min after titanic stimulation. Results Compared with group C, the amplitude of the field potential was significantly decreased and the latency period prolonged in group M and MN, but there was no significant difference in the above indices between group N and C. Compared with group M, the amplitude of the field potential was significantly increased and the latency period shortened in group MN. Compared with those 30 min before the tetanic stimulation, the amplitude of the field potential was significantly increased and latency period shorted at the time points after the tetanie stimulation in group C and N, the amplitude of the field potential was significantly decreased and latency period prolonged at the time points after the tetanie stimulation in group M, and the amplitude of the field potential was significantly increased 0-30 and 35-60 min after the tetanic stimulation and latency period shortened 0-30 min after the tetanie stimulation, the amplitude of the field potential was significantly decreased and latency period prolonged 65-120 and 125-210 min after the tetanic stimulation in group MN. Conclusion Morphine can inhibit synaptic LTP in the spinal dorsal horn evoked by electric stimulation of sciatic nerve in rats, and it may be one of the mechanisms of the central sensitization inhibition.
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Objective To investigate the clinical effect of combined use of remifentanil,propofol and high frequency jet ventilation for respiratory tract foreign body removal in children.Methods Fifty-two children undergoing respiratory tract foreign body removal operations were randomly divided into two groups: group A with remifentanil,propofol and high frequency jet ventilation(n=26),and group B with ketamine and sodium ?-hydroxybutrate(n=26).The changes of operation time,awaken time,vital signs and the incidence of intra/post-operative complications were observed.Results There was no significant differences in operation time,but awaken time in group A was significantly longer than that in group B(P