Relation of oxidative protein damage and nitrotyrosine levels in the aging rat brain.

An increase in oxidative stress may contribute to the development of oxidative protein damage in the aging rat brain. In the present study, we investigated the relation between nitrotyrosine levels and other oxidative protein damage parameters such as protein carbonyl and protein thiol, as well as oxidative stress parameters such as total thiol, nonprotein thiol, and lipid hydroperoxides in the brain tissue of young, adult, and old Wistar rats. Brain nitrotyrosine levels of old rats were significantly decreased compared with those of young rats. Young and adult rats were not significantly different as far as these parameters were concerned, however, brain protein carbonyl and lipid hydroperoxide levels of old rats were significantly increased compared with those of young and adult rats. On the other hand, brain tissue total thiol, nonprotein thiol, and protein thiol levels of old rats were significantly decreased compared with those of young and adult rats. The strong correlation we found between protein carbonyl and lipid hydroperoxide levels indicates a striking relation between protein oxidation and lipid peroxidation in the aging brain tissue. The results of this study suggest that protein carbonyl formation is both a sensitive and a specific marker of brain aging. However, decreased nitrotyrosine levels in old rats, in contradiction to the expected, may be due to mechanisms other than oxidative protein damage in the aging rat brain.

Effect of CO(2) insufflation on bacteremia and bacterial translocation in an animal model of peritonitis.

BACKGROUND: The widespread adoption of the laparoscopic approach has created some concern over the potential for increased risk of bacteremia and sepsis due to increased intraabdominal pressure in patients with intraabdominal infection and peritonitis. This study examines the effect of the CO(2) pneumoperitoneum on bacteremia and bacterial translocation. METHODS: New Zealand white rabbits were assigned into three groups of 10 animals. In group 1, 100 ml of sterile saline was infused into the peritoneal cavity under 10 mmHg CO(2) insufflation for 1 h. Group 2 received 100 ml of saline containing 10(9) CFU/ml (colony-forming units) E. coli strain 0163 and 10 mmHg CO(2) insufflation for 1 h. Group 3 received an identical bacterial inoculum, followed by a 10-cm midline laparotomy. Blood samples were taken for culture by cardiac puncture at various intervals during the experiment. At 6 h after being subjected to the experimental procedures, the rabbits were killed and their organs were cultured quantitatively for translocating bacteria. RESULTS: In group 1, neither blood nor organ cultures were positive, whereas in group 2 all blood cultures became positive in 1 h, and intraperitoneally infused bacteria translocated to the lung and kidney in all rabbits. In group 3, blood cultures became positive in 1 h, all but two of the rabbits had translocated bacteria in their lungs, and kidney samples from two of the rabbits were culture-positive. CONCLUSIONS: Our results indicate that both CO(2) pneumoperitoneum and laparotomy increase the incidence of bacterial translocation from the peritoneal cavity into the bloodstream. Thus, the risk of translocation to extraperitoneal organs such as lung and kidney is increased significantly by laparoscopy. Therefore, laparoscopic surgery should be avoided or used cautiously in the setting of acute peritonitis.