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Objective To investigate the variation in the position of conus medullaris in Chinese adult population in order to avoid hitting conus during spinal puncture. Methods Eight hundred patients suffering from back pain, aged 18-91 yr, were enrolled in this study. The position of conus medullaris was determined using Siemens 1.5 T magnetic resonance imaging system. According to the method described by Reimann, the vertebral body was used as mark of reference to the level of the end of conus. Results There were 190 patients in whom the position of the end of conus medullaris was lower than L1,2 . The incidence of the position of the end of conus medullaris lower than L1,2 was higher in patients 30-60 or older than in those under 30, and in those over the age of 60 than in those 30-60 (P ＜ 0.05). Conclusion Spinal puncture should be performed cautiously at L2,3. CT or MRI is recommended before operation for the patients to locate the position of conus medullaris and avoid injury to the spinal cord.
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Objective To evaluate the role of alpha4 beta2 neuronal nicotinic acetylcholine receptor in the inhibition of synaptic long-term potentiation (LTP) by isoflurane in the CA1 area of rat hippocampal slices.Methods Hippocampal slices (400 μm thick) were prepared from the brains of adult male SD rats, 2 months old, weighing 200-250 g, anesthetized with ether and decapitated. The slices were incubated in artificial cerebrospinal fluid (aCSF) at room temperature for at least 2 h before use. Seventy slices were randomly divided into 10 groups ( n = 7 each): Ⅰ LTP group in which the slices were perfused with aCSF; Ⅱ , Ⅲ and Ⅳ group in which the slices were perfused with aCSF containing isoflurane 0.125, 0.25 and 0.5 mmol/L respectively (group Ⅰ1-3 );Ⅴ and Ⅵ group in which the slices were perfused with aCSF containing epibatidine 0.1 and 1.0 μmol/L respectively (group E1.2 ); Ⅶ group epibatidine 0.1 μmol/L + isoflurane 0.25 mmol/L (group E1 + I2 ); Ⅷgroup epibatidine 1.0 μmol/L + isoflurane 0.25 mmol/L (group E2 + I2); Ⅸ group DHβE 0.1 μmol/L (group D); Ⅹ group DHβE 0.1 μmol/L + isoflurane 0.125 mmol/L (group D + I1 ). Population spikes (PS) were recorded for at least 30 min before LTP in each group. For LTP induction, high-frequency stimulation (HFS) was applied to the Schaffer collateral-commissural pathway of hippocampus and maintained for 15 min using a stimulating electrode.The changes in PS amplitude were analyzed at 5, 10, 15, 20, 25, 30, 40, 50 and 60 min after HFS in each group. Results Compared with group LTP, the PS amplitude was significantly decreased after HFS in group I1 ,I2, I3 , D, D + I1 and E1 + I2 ( P ＜ 0.05), while increased after HFS in group E1 .2 ( P ＜ 0.05 ), but no significant change was found after HFS in group E2 + I2 ( P ＞ 0.05). The PS amplitude was significantly decreased after HFS in group D + I1 compared with group I1 (P ＜ 0.05). The PS amplitude was significantly increased after HFS in group E1 + I2 and F2 + I2 compared with group I2 ( P ＜ 0.01 ). Conclusion Isoflurane inhibits LTP induction via inhibiting the activation of alpha4 beta2 nicotinic acetylcholine receptor in rat hippocampus.
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Objective To evaluate the hemodynamic responses of esmolol to nasotracheal intubation with fiberbronchoscope(FOB). Methods Thirty-five ASAⅠorⅡpatients undergone stomatology and otorhinolaryngology surgery were randomly divided into fiberoptic nasotracheal intubation esmolol group (esmolol group) and fiberoptic nasotracheal intubation group (control group). The intravenous administration of esmolol 1mg?kg-1 was performed 2 min before tracheal intubation in esmolol group. Noninvasive SBP,DBP,MBP,HR and SpO2 were recorded before and after anesthetic induction,at intubation and 1,2,3,4,5 min after intubation. Results The SBP,DBP and MBP 1 min after intubation in esmolol group were significantly lower than those in control group(P
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0.05),but it was significantly lower than that in LTP group (P
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Objective To evaluate the effects of patient controlled analgesia(PCEA)on the perioperative changes of circulatory and pulmonary function of elderly with hypertensions after abdominal surgery.Methods Twenty-eight patients of ASAⅡ-Ⅲ aged more than 60 years undergoing uratomy were randomly divided into two groups:control group and PCEA group.Preoperative and postoperative circulatory and pulmonary functions were measured with noninvasion circulatory monitor and pocket lung function meter respectively.Results In control group,the systolic pressure,diastolic pressure,and heart rate increased by 19%,17% and 19%,respectively,as compared with preoperation.The percentage of forced vital capacity(FVC%),percentage of forced expiratory volume in first second to forced vital capacity(FEV1%) and percentage of maximal ventilatory volume(MVV%) of postoperation in control group were significantly decreased compared with preoperation(P