Reactive Oxygen Species are Involved in Y-27632-induced Neurite Outgrowth in PC12 Cells

Inhibition of Rho-associated coiled coil-containing kinase (ROCK) has been reported to promote differentiation of neuronal cells. Here, we examined the effect of Y-27632, a ROCK inhibitor, on the outgrowth of neurites in PC12 cells. Y-27632 caused a rapid induction of neurite outgrowth in PC12 cells in a time-dependent manner. The neurite outgrowth, triggered by Y-27632, was accompanied by Rac1 activation, and was attenuated by Rac1 inhibitor NSC23766, in a concentration-dependent manner. Y-27632 also induced an increase in the production of reactive oxygen species (ROS). Pretreatment with N-acetylcysteine, an ROS scavenger, inhibited the ROS generation and neurite outgrowth in response to Y-27632. These results indicate that the activation of Rac1 and the generation of ROS contribute to the neurite outgrowth triggered by Y-27632 in PC12 cells.

Staurosporine Induces ROS-Mediated Process Formation in Human Gingival Fibroblasts and Rat Cortical Astrocytes

In the present study, we investigated the effect of staurosporine on the formation of cellular processes in human gingival fibroblasts and rat astrocytes. Staurosporine caused a rapid induction of process formation in human gingival fibroblasts and rat astrocytes in a concentration dependent manner. The process formation of human gingival fibroblasts and rat astrocytes was prevented by the pretreatment with N-acetylcysteine, suggesting that staurosporine-induced ROS production was responsible for the process formation. Colchicine, a microtubule depolymerizing agent, inhibited the staurosporine-induced process formation, whereas cytochalasin D, an actin filament breakdown agent, failed to suppress the formation of cellular processes. This result indicated that polymerization of microtubule, and not actin filament, was responsible for the formation of cellular processes induced by staurosporine. In support of this hypothesis, Western blot analysis was conducted using anti-tubulin antibody, and the results showed that the amount of polymerized microtubule was increased by the treatment with staurosporine while that of depolymerized beta-tubulin in soluble fraction was decreased. These results indicate that staurosporine induces ROS-mediated, microtubule-dependent formation of cellular processes in human gingival fibroblasts and rat astrocytes.

Effect of Ephedrine Infusion on the Prevention of Hypotension during Epidural Anesthesia / 대한마취과학회지

BACKGROUND: There has been no consensus on the best way to prevent hypotension during epidural anesthesia. We undertook the present study to evaluate the effect of ephedrine infusion along with fluid preloading in prevention of hypotension. METHODS: Eighty patients undergoing total abdominal hysterectomy were divided into 4 groups. The Group 1 and 2 were preloaded with 1000 ml lactated Ringer's solution(LR), Group 3 with 200 ml LR, and Group 4 with 500 ml of colloid(10% pentastarch) solution. In the group 1, normal saline was infused at 12 ml/min after bupivacaine injection into epidural space. In the Group 2, 3, and 4, ephedrine(mixed in normal saline) was infused after beginning of anesthesia at 1 mg/min. RESULTS: Systolic arterial pressure after epidural blockade was significantly lower in preloading of only LR(Group 1) than those with ephedrine infusion groups(Group 2, 3, and 4). In all groups the heart rate was not changed significantly during the course of the study. The central venous pressure increased after fluid preloading in all groups, but the magnitude of increase was relatively small in Group 3. Hypotension occurred in 45% of the patients who received only LR(Group 1) vs 10% of those who received pentastarch(Group 4)(p<0.05). The incidence of hypotension(20%) was same in Group 2 and 3. CONCLUSIONS: Infusion of ephedrine could be an alternative method to prevent hypotension during epidural anesthesia. Similar incidence of hypotension in Groups 2 and 3 challenges our perception of the value of crystalloid preload.

Evaluation of Airway Assessment factors for Predicting difficult intubation / 대한마취과학회지

BACKGROUND: Endotracheal intubation is a common procedure in anesthesia, which can usually be accomplished easily. However, if the attempt is unexpectedly difficult the patient may be seriously at risk. If we can anticipate difficult intubation by assessing the airways in advance, anesthesiologists can plan the safest and most effective way of managing tracheal intubation. The purpose of this study is to evaluate a correlation between airway assessment factors and laryngoscopic grades for predicting difficult intubation. METHODS: The data were collected from a total of 427(male 189) patients older than 16 years of age undergoing non-emergency surgery. Seven airway assessment factors, measured at three levels of severity, were evaluated. Airway assessment factors include inter incisor gap, Samsoon and Young classification, thyromental distance, head and neck movement, body weight, history of difficult intubation and buck teeth. RESULTS: There was a significant correlation between total airway score and laryngoscopic grade. The incidence of difficult intubations was 9 out of 427 patients. Samsoon and Young classification, thyromental distance, head and neck movement, history of difficult intubation were significantly independent airway factors for predicting difficult intubations. Increase of total airway score represents the risk of difficult intubations. CONCLUSION: We suggest that total airway score could be used as a valuable predictor for assessing difficult intubations.