ve In order to improve the reliability of somatosensory evoked potentials (SSEP) monitoring during anesthesia, we compared the effects of three commonly used volatile anesthetics on SSEP to choose suitable volatile anesthetic and determine the appropriate end-expiratory concentrations which have least effects on SSEP monitoring. Methods Sixty ASA I - II patients undergoing elective intracranial surgery were randomly divided into three groups: group A received enflurane; group B isoflurane and group C desflurane. The demographic data including age, body weight, height and sex were not significantly different between the three groups. In addition to SSEP, ECG, BP, SpO2, PET CO2 and end-tidal concentration of inhalation anesthetic were monitored. The SSEP electrodes were placed on N13 on the neck and N20 on the scalp. Before experiment the patient was asked to lie quietly for 10 min, then the patient started breathing 100% O2 and fresh-gas-flow (FGF) was set at 5 L/min. Median nerve on one side was stimulated and SSEP waves from cortex and cervical spinal cord were recorded as baseline tracing before anesthesia. The concentration of inhalation anesthetic was gradually increased from 0 to 0.3, 0.5, 0.75, 1.0 and 1.5 MAC. Each concentration was maintained for 15 min and SSEP waves were recorded. During experiment if the patient developed respiratory depression, oral airway was inserted and assisted ventilation was performed to maintain PETCO2 at 35-45minHg. If the patient developed hypotension, fluid was infused at an increased rate and vasopressor was given if necessary to maintain normal BP (baseline ? 20 % ) . Results The three volatile anesthetics did not change N13 latency and amplitude. Increasing concentrations of enflurane, isoflurane and desflurane were associated with graded reduction in N20 amplitude and increase in N20 latency and N13-N20 interpeak latency. Conclusions The results suggest (1) cortical SSEPs are moresensitive to the volatile anesthetics than subcortical SSEPs, (2) end-tidal concentration of enflurane less than 0.75 MAC is compatible with effective SSEP monitoring, whereas the end-tidal concentration of isoflurane or desflurane compatible with effective SSEP monitoring was less than 1.0 MAC. Enflurane has greater effect on SSEP than isoflurane and desflurane.

Objective To study the effect of magnetic field on serum activity of superoxide dismutase (SOD), content of malon-dialdehyde (MDA)and content of nitric oxide (NO)in patients undergoing operation for pituitary Tumor. Methods Sixteen ASA Ⅰor Ⅱ patients undergoing pituitary tumor surgery under general anesthesia were randomly divided into 2 groups (n=8 each): magnetic field group (M) and control group (C). Patients in magnetic field group were exposed in 150 mT magnetic field during the operation period.Blood samples were taken from radial artery for determination of serum SOD,MAD and NO before induction of anesthesia(T_0, baseline),after induction(T_1),70 min after induction(exposed in magnetic field for 60 min) (T_2)and 130 min after induction (exposed in magnetic field for 120 min) (T_3). Results There was no significant difference between the two groups in age, sex (M/F ratio),body weight,body height,duration of operation and duration of anaesthesia.The serum activity of SOD and content of NO were significantly higher at T_3 in group M than that in group C,and the serum content of MDA was lower at T_3 in group M than that in group C. Conclusions The magnetic field not only increases serum SOD activity and the content of NO in patient undergoing operation for pituitary tumor,but also reduces the content of MDA in them.

Objective To study the feasibility and reliability of median nerve somatosensory evoked potential monitoring in neurosurgery around the brain stem. Methods in selected 43 patients SEP N20, waveforms were recorded after stimulation of left and right median nerves respectively. Anesthesia was maintained with intravenous anesthetics throughout the operation. As soon as N20 waveform changed significantly, the surgeon was informed and the operative procedure was modified whenever possible. Results SEP waveforms were almost stable during maintaining with total intravenous anesthesia (TIVA). Within 43 cases, SEP waveform of & patients significantly changed. In these cases, SEP of 5 patients returned to normal gradually and no further neurologic dysfunction happened postoperatively. The other 3 cases did not recover, and postoperative neurologic complications happened. There was no false-negative or false-positive result. The correlation between intraoperative SEP changes and postoperative neurologic alterations was significant statistically. Conclusions SEP recording is a reliable technique for intraoperative monitoring during neurosurgery around the brain stem. TIVA is helpful for SEP monitoring.

Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.

Objective: To study the effect of three different doses of propofol, midazolam and etomidate on short latency somatosensory evoked potential(SLSEP). Method:Ninety patients undergoing elective operation were randomly divided into 3 groups with 3 subgroups each,and propofol,midazolam,etomidate were administered by bolus injection at propofol 1.5,2,3mg/kg, midazolam 0.2,0.3,0.4mg/kg, etomidate 0.15,0.3,0.4mg/kg accordingly. SLSEP was recorded before,during and after injection. Result:Propofol did not significantly change the latencies of the subcortical N_(14),cortical N_(20) and central conduction time(CCT)N_(14)-N_(20),decreased the interwave amplitude N_(20)-P_(25)(P

Microglial surveillance plays an essential role in clearing misfolded proteins such as amyloid-beta, tau, and α-synuclein aggregates in neurodegenerative diseases. However, due to the complex structure and ambiguous pathogenic species of the misfolded proteins, a universal approach to remove the misfolded proteins remains unavailable. Here, we found that a polyphenol, α-mangostin, reprogrammed metabolism in the disease-associated microglia through shifting glycolysis to oxidative phosphorylation, which holistically rejuvenated microglial surveillance capacity to enhance microglial phagocytosis and autophagy-mediated degradation of multiple misfolded proteins. Nanoformulation of α-mangostin efficiently delivered α-mangostin to microglia, relieved the reactive status and rejuvenated the misfolded-proteins clearance capacity of microglia, which thus impressively relieved the neuropathological changes in both Alzheimer's disease and Parkinson's disease model mice. These findings provide direct evidences for the concept of rejuvenating microglial surveillance of multiple misfolded proteins through metabolic reprogramming, and demonstrate nanoformulated α-mangostin as a potential and universal therapy against neurodegenerative diseases.