title: Plasma protein oxidation in patients with brain tumors.
abstract: OBJECTIVE
  Proteins can undergo numerous covalent changes on exposure to oxidants. Oxidative modification of protein in vivo may affect a variety of cellular functions. Protein oxidation in vivo is a natural consequence of aerobic life. Oxygen radicals and other activated oxygen species generated as byproducts of cellular metabolism or from environmental sources cause modifications to the amino acids of proteins that generally result in loss of protein function/enzymatic activity. It is now well known that reactive oxygen species (ROS) play a key role in human cancer development. Moreover, the brain is especially vulnerable to ROS mediated injury.
  
  
  METHODS
  Therefore, in the present study, protein oxidation was assessed in the plasma of 17 patients with brain tumors and 16 age and gender-matched controls by measuring protein thiols and protein carbonyls spectrophotometrically.
  
  
  RESULTS
  There was a significant decrease in protein thiols and carbonyls in malignant cases of brain tumors when compared with the control group. No significant change in protein thiols was noted in benign cases compared to controls. A comparison of levels in benign and malignant cases for both the parameters also showed no significant difference.
  
  
  CONCLUSIONS
  Thus, free radical toxicity does lead to protein oxidation in patients with brain tumors.
authors.affiliation: Department of Biochemistry, Kasturba Medical College and Hospital, Manipal 576104, Karnataka, India.
authors.forename: Prem
authors.initials: P
authors.lastname: Kumar
authors.forename: Uma
authors.initials: U
authors.lastname: Devi
authors.forename: Sabir
authors.initials: S
authors.lastname: Ali
authors.forename: Ramya
authors.initials: R
authors.lastname: Upadhya
authors.forename: Sailaja
authors.initials: S
authors.lastname: Pillai
authors.forename: Annaswamy
authors.initials: A
authors.lastname: Raja
authors.forename: Suryanarayana
authors.initials: S
authors.lastname: Rao
authors.forename: Anjali
authors.initials: A
authors.lastname: Rao
mesh_terms: D000328:Adult; D001798:Blood Proteins / Q000378:metabolism*; D001932:Brain Neoplasms / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D050050:Protein Carbonylation; D017382:Reactive Oxygen Species / Q000097:blood; D013438:Sulfhydryl Compounds / Q000097:blood*
chemical_list: D001798:Blood Proteins; D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds