A method was developed for the determination of chloramphenicol residue in milk powder by UPLC-MS/MS.The residue was extracted with ethylacetate from the milk powder,cleaned up by C18 SPE column,and detected by electr...A method was developed for the determination of chloramphenicol residue in milk powder by UPLC-MS/MS.The residue was extracted with ethylacetate from the milk powder,cleaned up by C18 SPE column,and detected by electrospray ionization and in the negative ion mode.The method had higher sensitivity and shorter analytical time,and was suitable for determination of chloramphenicol in milk powder.展开更多
Objective: To investigate the roles of chloramphenicol (CAP) preconditioning in the oxidative respiratory function of cerebral mitochondria in rats exposed to acute hypoxia during acute hypoxia by observing the change...Objective: To investigate the roles of chloramphenicol (CAP) preconditioning in the oxidative respiratory function of cerebral mitochondria in rats exposed to acute hypoxia during acute hypoxia by observing the changes of mitochondrial oxidative respiratory function and cytochrome C oxidase (COX) activity. Methods: Adult male Wistar rats were randomly divided into 4 groups: control (C), medication (M), hypoxia (H), and medication plus hypoxia (MH). Rats in groups M and MH were administered by peritoneal injection of CAP (50 mg/kg) every 12 h for 7 d before decapitation, but those in groups H and MH were exposed to a hypobaric chamber simulating 5 000 m high altitude for 24 h. The rat cerebral cortex was removed and mitochondria were isolated by centrifugation. Mitochondrial respiratory function and COX activity were measured by Clark oxygen electrode. Results: Compared with Group C, Group H showed significantly elevated state 4 respiration (ST 4), decreased state 3 respiration (ST 3), and respiratory control rate (RCR) in mitochondrial respiration during acute hypoxic exposure. ST 3 in Group MH was significantly lower than that in Group C, but was not significantly different from that in Groups H and M, while ST 4 in Group MH was significantly lower than that in groups C and H. RCR in Group MH was higher than that in Group H, but lower than that in Group C. COX activity in Group H was significantly lower than that in Group C. In Group MH, COX activity increased and was higher than that in Group H, but was still lower than that in Group C. Conclusion: Acute hypoxic exposure could lead to mitochondrial respiratory dysfunction, suggesting that CAP preconditioning might be beneficial to the recovery of rat respiratory function. The change of COX activity is consistent with that of mitochondrial respiratory function during acute hypoxic exposure and CAP-administration, indicating that COX plays an important role in oxidative phosphorylation function of mitochondria from cerebral cortex of hypoxic rats.展开更多
文摘A method was developed for the determination of chloramphenicol residue in milk powder by UPLC-MS/MS.The residue was extracted with ethylacetate from the milk powder,cleaned up by C18 SPE column,and detected by electrospray ionization and in the negative ion mode.The method had higher sensitivity and shorter analytical time,and was suitable for determination of chloramphenicol in milk powder.
文摘Objective: To investigate the roles of chloramphenicol (CAP) preconditioning in the oxidative respiratory function of cerebral mitochondria in rats exposed to acute hypoxia during acute hypoxia by observing the changes of mitochondrial oxidative respiratory function and cytochrome C oxidase (COX) activity. Methods: Adult male Wistar rats were randomly divided into 4 groups: control (C), medication (M), hypoxia (H), and medication plus hypoxia (MH). Rats in groups M and MH were administered by peritoneal injection of CAP (50 mg/kg) every 12 h for 7 d before decapitation, but those in groups H and MH were exposed to a hypobaric chamber simulating 5 000 m high altitude for 24 h. The rat cerebral cortex was removed and mitochondria were isolated by centrifugation. Mitochondrial respiratory function and COX activity were measured by Clark oxygen electrode. Results: Compared with Group C, Group H showed significantly elevated state 4 respiration (ST 4), decreased state 3 respiration (ST 3), and respiratory control rate (RCR) in mitochondrial respiration during acute hypoxic exposure. ST 3 in Group MH was significantly lower than that in Group C, but was not significantly different from that in Groups H and M, while ST 4 in Group MH was significantly lower than that in groups C and H. RCR in Group MH was higher than that in Group H, but lower than that in Group C. COX activity in Group H was significantly lower than that in Group C. In Group MH, COX activity increased and was higher than that in Group H, but was still lower than that in Group C. Conclusion: Acute hypoxic exposure could lead to mitochondrial respiratory dysfunction, suggesting that CAP preconditioning might be beneficial to the recovery of rat respiratory function. The change of COX activity is consistent with that of mitochondrial respiratory function during acute hypoxic exposure and CAP-administration, indicating that COX plays an important role in oxidative phosphorylation function of mitochondria from cerebral cortex of hypoxic rats.
