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Objective:To develop a novel sustained-release local anesthetic microspheres and evaluate the effects on sciatic nerve block in rabbits.Methods:The magnetic lidocaine microspheres were prepared by W 1/O/W 2 compound emulsion method, investigating their external morphology, measuring the magnetic response characteristics by the VSM and draw the hysteresis loop.The encapsulation efficiency and drug-loading rate were calculated, and the cumulative release curves in vitro were drawn.Fifteen healthy rabbits (half male and half female), aged 5-6 months, weighing 3.0-3.5 kg, were selected for sciatic nerve block and divided into 3 groups ( n=5 each) using a random number table method: magnetic response lidocaine microspheres group (PL group), normal saline control group (C group) and lidocaine group (L group). Magnetic response lidocaine microsphere buffer 2 ml, normal saline 2 ml and 2% lidocaine 2 ml were injected around the rabbit sciatic nerve through a catheter in PL, C and L groups, respectively.The applied magnetic field was withdrawn at 60 h after injection.Before injection (T 0) and at 30 min and 2 , 8, 16, 24, 48, 60, 62 and 64 h after injection (T 1-9), the compound action potentials and conduction velocities of bilateral sciatic nerve trunks were measured, and block was assessed using toe reflex score and modified Tarlov score. Results:The magnetic lidocaine microspheres were brown in color and observed as monodisperse, regular spheres with a diameter of (9±3) μm, an encapsulation rate of 46.18%, a drug loading of 6.02%, and a superparamagnetic release rate of 97% in vitro at 60 h. The hysteresis loop passed through the origin and no hysteresis occurred with the absence of an external magnetic field.Compared with C group, the action potentials and conduction velocities of the sciatic nerve, toe reflex score and modified Tarlov score were significantly decreased at T 1-T 8 in PL group ( P<0.05). Compared with L group, the action potentials and conduction velocities of the sciatic nerve were significantly increased at T 1, the action potential was decreased at T 2-T 8, the conduction velocity was decreased at T 3-T 8, the toe reflex score was increased at T 1 and decreased at T 3-T 8, and the modified Tarlov score was increased at T 1 and T 2 and decreased at T 3-T 8 in PL group ( P<0.05). Conclusions:Magnetic response lidocaine microsphere is successfully developed with good magnetic responsiveness and release and can prolong the sciatic nerve block time in rabbits.
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Objective To investigate the regulation effect of bispectral index (BIS) on the depth of total intravenous anesthesia (TI-VA) by comparing with regulating the depth of anesthesia according to the changes of hemodynamics. Methods 60 ASA Ⅰ～Ⅱ patients undergoing laparoscopic cholecystectomy (LC) were randomly assigned into controlled group (group C) and trial group (group T) ,with 30 patients in each group, according to the rules of regulating the titration of propofol during TIVA. The target of group C was to keep SBP/DBP 100 ～ 140mmHg/60 ～ 89mmHg and that of group T was to keep BIS 40 ～ 60 during anesthesia. The measure indexes included SBP/DBP, HR, BIS, total dosis of Propofol, time to extubate, time to leave operating room and OAA/S (observer's assessment of alert-ness/sedation). After operation, we evaluated whether awareness during surgery happens. Results As compared with group C, there were higher SBP/DBP and BIS in group T after induction of anesthesia, during aeroperitonia, immediately after finishing operation and just before extubating endotracheal catheter, but less dosis of propofol and less time of extubation and leaving operating room in group T. The differences had significance (P <0.01). There were no significant differences in the changes of HR between two groups (P >0.05) and no awareness during surgery happened in both groups. Conclusion TIVA regulated by BIS during LC can decrease the dosis of propofol, accelerate the recovery from anesthesia and avoid extremely deep anesthesia and awareness during surgery.
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Objective:To investigate the effect of RPM on bcl-2 and Fas protein expressions at different ischemia-reperfusion points.Methods:Acute ischemic renal injury model was established(right kidney ectomized,45 min of left renal ischemia and reperfusion for Oh,24h,48h and 72h).Fifty four normal male Wistar rats were.randomly divided into 3 groups:sham-operated group(sham,without renal ischemia),ischemia-reperfusion group(IR,without RPM),RPM and ischemia-reperfusion group(RPM 4mg/(kg?d)?3d,reperfusion at 2h before,operation and each observation day).Pathomorphological changes of renal ischemia- reperfusion injury were observed by HE stain and SABC immunohistochemical methods were used to detect the changes of expressions of bcl-2 and Fas.Results:bcl-2 and Fas concentration were significantly higher in IR group than those in sham group(P
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Objective:To investigate the effect of rapamycin on renal function and ultrastructure changes after renal ischemia-reperfusion in rats.Methods:Acute ischemic renal injury model was established(right kidney ectomized,45 min of left renal ischemia and reperfusion for 24h).Thirty male Wistar rats were randomly divided into 3 groups:sham operation group(control group or group C,without renal ischemia),renal ischemia-reperfusion group(ischemia-reperfusion group or group I,without rapamycin),renal ischemia-reperfusion and(RPM 4mg/(kg?d)?3d,reperfusion at 2h before the last operation) intravenous injection group(rapamycin group or group U).changes of renal function and renal uhrastructure were measured BUN level,serum creatinine values.Results:Serum creatinine(168?37)?mol/L and BUN concentration(22?6)mmol/L in group I were significantly higher than those in group U:serum creatinine(113?17)?mol/L and BUN concentration(13.8?2.3)mmol/L(P