Objective To investigate the toxic effects of ozone on rat astrocytes in vitro. Methods Twelve 1-2 day old Wistar rats were anesthetized with ether. Their brains were removed. Astrecytes were enzymatically isolated with trypsin and cultured. After different-speed cultivation and serial passage, astrocytes were seeded into 24 well plates and divided into 4 groups (n = 7 each): group Ⅰ normal control (group C) and group Ⅱ , Ⅲ , Ⅳ (group O2-O340, 60, 80) were exposed to ozone 40, 60 and 80 μg/ml respectively. After 2 and 4 h incubation, the astroeytes were examined under microscope. Supernatant was collected and cells were broken for determination of SOD activity and MDA content in the cells and LDH leaking ratio. Results Cells in group O2-O3 60 and 80 exhibited hypertrophy, vacuoles and black denatured grains in the cytoplasm and increase in proceses. SOD activity and MDA content were significantly increased at the end of 2 h incubation in group O2-O340, 60 and 80 as compared with blank control group. LDH leaking ratio and MDA content were increased in a concentration dependent manner at the end of 2 h and 4 h incubation, while SOD activity was decreased concentration dependently at the end of 4 h incubation. SOD activity was signifieandy decreased, while LDH leaking ratio was increased at 4 h as compared with that at 2 h in group O2-O360 and 80. Conclusion Ozone has toxic effects on cultured rat astroeytns in a concentration and time dependent manner.

Objective To investigate the effects of ropivacaine infiltration combined with dezo-cine intravenous on stress response during recovery from general anesthesia in patients undergoing e-sophageal cancer surgery.Methods One hundred and forty-four patients of esophageal cancer under-going elective surgery were randomly divided into dezocine group (group D,n = 48 ),ropivacaine group (group R,n =47)and ropivacaine combined with dezocine group (group RD,n =49 ).Before slicing 10 min,patients in group D were taken 20 ml saline infiltration anesthesia (1∶200 000 epi-nephrine),while in group R and group RD were taken 20 ml 0.5% ropivacaine infiltration anesthesia. Patients in the group R were injected intravenously 2 ml saline,while in group D and group RD were injected intravenously 10 mg dezocine 30 min before the end of surgery.Peri-operative bleeding,oper-ation time,recovery time of anesthesia,extubation time and the dosage of propofol and sufentanil of three groups were recorded respectively.At the time points of before induction of anesthesia (T0 ), the end of the surgery (T1 ),removal trachea immediate (T2 ),10 min (T3 )and 30 min (T4 ),the blood pressures and heart rates were recorded,and the serum levels of malondialdehyde (MDA),epi-nephrine (E)and norepinephrine (NE)were detected.Results Recovery time of anesthesia and extu-bation time in group R and group RD were shorter than that in group D significantly (P <0.05).The dosage of propofol and sufentanil in group R and group RD were less than that in group D significantly (P <0.05).Compared with T0 ,SBP in three groups were elevated significantly at T1-T4 (P <0.05), DBP and HR in group D and group R increased significantly at T3 (P <0.05).DBP and HR in group RD at T3 were lower than that in group D and group R significantly (P <0.05).Compared with T0 , the levels of blood sugar,Cor,MDA,E and NE in three groups were elevated significantly at T1-T4 (P <0.05).The levels of blood sugar,Cor,MDA,E and NE in group RD at T1-T4 were lower than that in group D and group R significantly(P < 0.05 ).The incidences of agitation and elevation of blood pressure in group RD were lower than that in group D and group R significantly (P <0.05 ). Conclusion Ropivacaine infiltration combined with dezocine intravenous applied in the esophageal cancer surgery could effectively reduce the stress response during recovery from anesthesia,and de-crease the incidence of agitation.