Objective To study the changes in somatosensory evoked potential caused by injection of adriamycin magnetic gelatin microspheres into subarachnoid space of rabbits. Methods Thirty rabbits were randomly divided into 5 groups: sham operation group (group S), gelatin microspheres 5mg (group C1), 15mg of gelatin microsphere (group C2) controlled groups, and adriamycin microspheres 5mg (group A1) and 15mg (group A2) groups. Under the effect of magnet, microspheres were injected into the subarachnoid space of rabbits. The pain threshold of electronic stimulation, motor function of rabbits′ hinder limbs and somatosensory evoked potential (SEP) were observed continuously. Results Obvious rise of pain threshold was found in group A2 (P

Objective To compare the analgesic effects between methylene blue and adriamycin magnetic gelatin microballoons on blocking the cornu dorsale medullae spinalis of rabbit,and to investigate its mechanism.Methods 40 rabbits were randomly divided into 7 groups including sham operation group,gelatin microballoon controlled group(5mg and 15mg),methylene blue microballoon group(5mg and 15mg)and adriamycin microballoon group(5mg and 15mg).Under the guide of magnet,microballoons were infused into subarachnoid space of rabbits.The pain threshold of electronic stimulation and motor function of rabbits' hind limbs were observed continuously.The somatosensory evoked potential was recorded.Results The pain threshold was raised obviously(P

Objective To prepare adriamycin gelatin microballoons and identify its characteristics,and to study the feasibility of utilizing the microballoon to block the conduction of peripheral nerves.Methods Adriamycin was embedded in gelatin by means of emulsify-cross link,and its physical-chemical property was tested.Thirty male SD rats were randomly divided into 3 groups including control group(group N),adriamycin group(group A)and adriamycin gelatin microballoon group(group M).0.1% Tween saline,0.5% adriamycin and the suspension of adriamycin gelatin microballoons were dropped separately onto the surface of denuded right sciatic nerve.The pain threshold of right hind limb,sciatic nerve function index(SFI)and pathological change were observed.Result The optimal proportion of drug and carrier was 1∶10.The microballoon was round in shape with perfect dispersibility.90% of the active ingredient could be released from the microballoons within 240 minutes.The pain thresholds in both groups A and M were elevated obviously,and the value of SFI was decreased markedly.These phenomena lasted only 60 days in group A,whereas over 90 days in group M.Conclusions The adriamycin gelatin microballoons possess a good appearance and a satisfactory performance of delayed release.It can damage eperipheral nerve,and may be used as a long acting neurolytic agent.

Objective To determine the optimal dose range of naloxone to enhance the analgesic effect of morphine.Methods One half of a total of 84 adult male Sprague-Dawley rats were randomly assigned into seven groups(6 rats for each group).Rats in group NS received normal saline,and in group M received 6mg/kg of morphine.Different doses of naloxone(1?g/kg,100ng/kg,10ng/kg,1ng/kg and 0.1ng/kg)with 6mg/kg of morphine were given to the rats in group MN1,group MN2,group MN3,group MN4 and group MN5.Pain thresholds were determined at different time points before and after subcutaneous injection of normal saline or morphine or mixture of the drugs(morphine and naloxone).Another 42 rats were randomly assigned into seven groups similar to the above grouping,but the morphine doses for group M and groups MN were changed to 2mg/kg.Acute pain was prodused by an in cision on the hind paw.Then they were given subcutaneous injection of the drugs in different doses as categorized above.Cumulative pain scores were observed within an hour.Results Compared with group NS,the pain thresholds of all the other groups were significantly increased at the time points from 5 minutes to 120 minutes after subcutaneous injection(P0.05).Conclusions Low-dose of naloxone can enhance the analgesic effect of morphine,and the dose range 1ng/kg~100ng/kg may be acceptable.Dose of 1?g/kg naloxone may antagonize the analgesic effect of morphine,while dose of 0.1ng/kg naloxone,perhaps,is too low to show an effect.

Objective: In order to search the credible parameters of evoked potentials (EP) for the depth of anesthesia. Method: The end-expiratory concentration of isoflurane was increased gradually from 0.2MAC by step of 0.1MAC in each of ten volunteers. The change of EP and the consciousness were observed at every end expiratory anesthetic concentrations. The explicit and implicit memories about intra-experiment events were investigated an hour after stopping inhalation of isoflurane. Result: The explicit memory disappeared at 0.2 and 0.3MAC of isoflurane without the stimulation of pain; The response to command disappeared at 0.3 and 0.4MAC; 0.4MAC of isoflurane could not vanish implicit memory in all subjects. The latencies of waves Pa and Nb of the MLAEP and P_(25) of the SEP prolonged gradually with increased concentrations of isoflurane in a linear relationship, and varied with the changes of response to command. The latency corresponding to the partial response increased significantly compared with that to the full response, but without difference between the partial and no response. Meanwhile the latencies of waves Pa, Nb and P_(25) increased significantly with the disappearances of explicit and implicit memory, without differences between the conscious and unconscious awareness. The critical values of latencies about those waves which could be applied to assess the disappearance of explicit memory, were defined. Conclusion: The disappearance of consciousness is not all-ornone but gradual. The sequence of disappearance about consciousness is explicit memory, response to command, then implicit memory. There is no explicit memory about stimulation of pain after response to command has vanished, but implicit memory may still exit. The waves Pa and Nb of MLAEP and the wave P_(25) of SEP may be regarded as important parameters to evaluate the depth of anesthesia about consciousness.

effect-site concentration. The cutoff points of BIS index, AEPI and effect-site concentration for implicit memory were 47, 28 and 2.3 ?g ? ml-1 respectively.Conclusion Implicit memory exists in unconscious patients when there is no noxious stimulation. Implicit memory disappears at level 1 of OAA / S score. Implicit memory score correlates well with BIS index, AEPI. The BIS index, AEPI and effect-site concentration are good predictors of implicit memory during target-controlled infusion of propofol.

Objective To evaluate the neurotransmitter mechanism and protective efficiency of three methods of isoflurane intervention on global cerebral ischemia, and to seek an effective method to improve cerebral ischemia damage. Methods Adult male Sprague-Dawley rats were randomly divided into sham operation group, control groups, preconditioning groups, protective groups and resuscitation groups. The rats of the last four groups were further divided into 10, 15 and 20min ischemia subgroups. The model of global cerebral ischemia and reperfusion was reproduced in waking rats 2 days before ischemia. The microdialysis samples were collected and BIS was recorded after reperfusion. The recovery of right reflection was observed after ischemia and the motor function was observed. All viable and apoptotic neurons were counted and the percentage of apoptotic neurons was calculated. The results showed that glutamate concentration in the hippocampus of protective groups was significantly lower compared with preconditioning group and resuscitation group. Results With ischemia fasting 10 and 15min (P

0.05). Conclusion Mb-MGM have good properties of drug-targeting and sustained drug releasing properties. Mb-MGM could be used for targeting spinal cord dorsal ganglia for nerve blocking after being injected into the subarachnoid space and under effect of magnet. The motor function is not affected.

Objective To compare the analgesic effect of morphine combined with lornoxicam in different proportions in rats. Methods 63 male adult SD rats were assigned randomly into nine groups (7 each). Under the 1.4% isoflurane anesthesia, an incision of 1cm in length was made in the plantar region of the left hind paw parallel to the muscle according to the method of Brennan. The rats in sham operation group (A) inhaled 1.4% isoflurane for 5 min but no incision was made, the rats in operation control group (B) received hypodermic injection of 1ml 0.9% NaCl 1h after incision, the rats in groups C to H and group L received hypodermic injection of morphine combined with lornoxicam in different proportions (6mg/kg∶0mg/kg; 1mg/kg∶5mg/kg; 2mg/kg∶4mg/kg; 3mg/kg∶3mg/kg; 4mg/kg∶2mg/kg; 5mg/kg∶1mg/kg and 0mg/kg∶6mg/kg, respectively) 1h after incision. Analgesic effect was assessed by cumulative pain score within 1 hour after administration. Results The cumulative pain scores of rats in group A was 0.375?0.518, which was significantly lower than that of the other groups (P0.05). The scores in groups F and G were 3.625?1.061 and 3.750?1.165 respectively, which were significantly lower than those in groups C, D, E and L (P

Objective To explore the differences between patients withchronic mountain sickness (CMS) and healthy people in the microstructure of brain gray and white matter by using diffusion kurtosis imaging (DKI). Methods 21 CMS patients were recruited to a study group and 20 healthy volunteers were assigned to a control group. Both groups received conventional MRI and DKI sequence scans. The mean kurtosis (MK) values ,radial kurtosis (RK) values and kurtosis anisotropy (KA) values in each region of interest (ROI) in the cerebral gray and white matter were measured and the same part of the left and right side ROI parameters was counted. The data satisfied the normal distribution and the paired samples t?test was used;the ROI parameters between the two groups in the same parts of the same side followed the normal distribution and the two independent samples t?test was used. Results The KA values in both sides of the anterior limb of internal capsule ,the MK values and RK values in bilateral caudate nucleus head and thalamus had side difference in CMS group. In both sides of the anterior limb of the internal capsule′s MK values,KA values and thalamus′s MK values,RK values existed side difference in the control group. The KA values of the right anterior limb in internal capsule were lower than those in the left in both groups;the right thalamus′s MK values and RK values were higher than the other side. The RK value in genu of corpus callosum differed significantly ,and it was lower the CMS group than in the control group. The difference of the KA values in corpus callosum ,the MK value in the left anterior limb of internal capsule ,the RK values in the left posterior limb of internal capsule ,the MK values in the right caudate nucleus head ,the MK values in bilateral lenticular nucleus and the MK values and KA values in the right thalamus were significant ,and they were higher inthe CMS group than in the control group. Conclusions The left and right cerebral hemispheric micro?structure is not exactly symmetrical between patients with CMS and healthy people living in high altitude areas , there are differences in some brain areas. The sensitivity and reactivity of brain tissue to high altitude hypoxia are different in patients with CMS ,there are various degrees of difference between the CMS and the normal in the corpus callosum,basal ganglia region and thalamus.