AIM: Experimental studies suggest that free radicals are involved in acid and pepsin-induced damage of esophageal mucosa. The profile and balance between free radicals and antioxidant systems in human esophagitis are ...AIM: Experimental studies suggest that free radicals are involved in acid and pepsin-induced damage of esophageal mucosa. The profile and balance between free radicals and antioxidant systems in human esophagitis are unknown. METHODS: Superoxide anion and its powerful oxidant reaction with nitric oxide (peroxynitrite) generation were determined in esophageal mucosal biopsies from 101 patients with different gastro-esophageal reflux diseases and 28 controls. Activity of both superoxide dismutase (SOD) and catalase, and reduced glutathione (GSH) levels, were also assessed. Expression of Cu,ZnSOD, MnSOD and tyrosine-nitrated MnSOD were analyzed by Western blot and/or immunohistochemistry. RESULTS: The highest levels of superoxide anion generation were found in patients with severe lesions of esophagitis. Peroxynitrite generation was intense in Barrett's biopsies, weaker in esophagitis and absent/weak in normal mucosa. Expression of Cu,ZnSOD and MnSOD isoforms were present in normal mucosa and increased according to the severity of the lesion, reaching the highest level in Barrett's esophagus. However, SOD mucosal activity significantly decreased in patients with esophagitis and Barrett's esophagus, which was, at least in part, due to nitration of its tyrosine residues. Catalase activity and GSH levels were significantly increased in mucosal specimens from patients with esophagitis and/or Barrett's esophagus. CONCLUSION: A decrease in SOD antioxidant activity leading to increased mucosal levels of superoxide anion and peroxynitrite radicals may contribute to the development of esophageal damage and Barrett's esophagus in patients with gastroesophageal reflux. Administration of SOD may be a therapeutic target in the treatment of patients with esophagitis and Barrett's esophagus.展开更多
OBJECTIVE: To analyze the epidemiology of hospital and community-acquired infections caused by Klebsiella pneumoniae (K. pneumoniae) and risk factors for infections caused by resistant strains. METHODS: A retrospecti...OBJECTIVE: To analyze the epidemiology of hospital and community-acquired infections caused by Klebsiella pneumoniae (K. pneumoniae) and risk factors for infections caused by resistant strains. METHODS: A retrospective observational study was performed to analyze the relationship between antimicrobial use and bacterial resistance. RESULTS: A K. pneumoniae infection was diagnosed in 0.47% of patients (169 of 36 179) admitted to the hospital between 1 March 1999 and 31 August 2000. Of the 169 isolates, 166 (98.2%) were resistant to at least one antimicrobial and 91.1% (154/169) to two or more antibiotics. 98% were resistant to ampicillin, 77% to piperacillin, 64% to cephalothin, 60% to ampicillin/sulbactam, 59% to cefoperazone, 57% to cefazolin, 55% to cefuroxime, 51% to TMP-SMZ, 51% to tobramycin, 50% to gentamicin, 49% to aztreonam, cefetaxime and ceftriaxone respectively, 47% to ceftazidime, 47% to cefepime, 46% to ciprofloxacin, 46% to ticarcillin/clavulanate, 44% to amikacin, 38% to cefoxitin, 22% to piperacillin/tazobactam, while all strains were tested susceptible to imipenem. CONCLUSIONS: Prior receipt of amtimicrobial therapy was significantly associated with infection caused by a resistant organism and most strains were resistant to multiple antibiotics.展开更多
基金Supported by the grant FIS 99/0569 from the Fondo de Investigaciones Sanitarias and Instituto de Salud Carlos Ⅲ (C03/02)
文摘AIM: Experimental studies suggest that free radicals are involved in acid and pepsin-induced damage of esophageal mucosa. The profile and balance between free radicals and antioxidant systems in human esophagitis are unknown. METHODS: Superoxide anion and its powerful oxidant reaction with nitric oxide (peroxynitrite) generation were determined in esophageal mucosal biopsies from 101 patients with different gastro-esophageal reflux diseases and 28 controls. Activity of both superoxide dismutase (SOD) and catalase, and reduced glutathione (GSH) levels, were also assessed. Expression of Cu,ZnSOD, MnSOD and tyrosine-nitrated MnSOD were analyzed by Western blot and/or immunohistochemistry. RESULTS: The highest levels of superoxide anion generation were found in patients with severe lesions of esophagitis. Peroxynitrite generation was intense in Barrett's biopsies, weaker in esophagitis and absent/weak in normal mucosa. Expression of Cu,ZnSOD and MnSOD isoforms were present in normal mucosa and increased according to the severity of the lesion, reaching the highest level in Barrett's esophagus. However, SOD mucosal activity significantly decreased in patients with esophagitis and Barrett's esophagus, which was, at least in part, due to nitration of its tyrosine residues. Catalase activity and GSH levels were significantly increased in mucosal specimens from patients with esophagitis and/or Barrett's esophagus. CONCLUSION: A decrease in SOD antioxidant activity leading to increased mucosal levels of superoxide anion and peroxynitrite radicals may contribute to the development of esophageal damage and Barrett's esophagus in patients with gastroesophageal reflux. Administration of SOD may be a therapeutic target in the treatment of patients with esophagitis and Barrett's esophagus.
基金ThisworkwassupportedbytheNaturalScienceFoundationofAnhuiEducationalBoard (No 2 0 0 1kj14 1)
文摘OBJECTIVE: To analyze the epidemiology of hospital and community-acquired infections caused by Klebsiella pneumoniae (K. pneumoniae) and risk factors for infections caused by resistant strains. METHODS: A retrospective observational study was performed to analyze the relationship between antimicrobial use and bacterial resistance. RESULTS: A K. pneumoniae infection was diagnosed in 0.47% of patients (169 of 36 179) admitted to the hospital between 1 March 1999 and 31 August 2000. Of the 169 isolates, 166 (98.2%) were resistant to at least one antimicrobial and 91.1% (154/169) to two or more antibiotics. 98% were resistant to ampicillin, 77% to piperacillin, 64% to cephalothin, 60% to ampicillin/sulbactam, 59% to cefoperazone, 57% to cefazolin, 55% to cefuroxime, 51% to TMP-SMZ, 51% to tobramycin, 50% to gentamicin, 49% to aztreonam, cefetaxime and ceftriaxone respectively, 47% to ceftazidime, 47% to cefepime, 46% to ciprofloxacin, 46% to ticarcillin/clavulanate, 44% to amikacin, 38% to cefoxitin, 22% to piperacillin/tazobactam, while all strains were tested susceptible to imipenem. CONCLUSIONS: Prior receipt of amtimicrobial therapy was significantly associated with infection caused by a resistant organism and most strains were resistant to multiple antibiotics.
