No effect of melatonin on oxidative stress after laparoscopic cholecystectomy: a randomized placebo-controlled trial.
ABSTRACT Melatonin, an endogenous circadian regulator, also has antioxidant and anti-inflammatory properties. The aim of this study was to evaluate the antioxidative effect of melatonin in patients undergoing laparoscopic cholecystectomy.
Patients were randomized to receive 10 mg melatonin or placebo during surgery. Blood samples for analysis of malondialdehyde (MDA), ascorbic acid (AA), total ascorbic acid (TAA) dehydroascorbic acid (DHA) and C-reactive protein (CRP) were collected pre-operatively and at 5 min, 6 h and 24 h after operation.
Twenty patients received melatonin and 21 patients received placebo during surgery. No significant differences were observed between the groups in the oxidative stress variables MDA, TAA, AA and DHA or in the inflammatory variable CRP (repeated-measures ANOVA, P>0.05 for all variables).
Administration of 10 mg melatonin did not reduce variables of oxidative stress in patients undergoing elective laparoscopic cholecystectomy.
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ABSTRACT: The concentrations of the hydrophilic antioxidants ascorbic acid and dehydroascorbic acid in plasma for some time have been considered possible biomarkers of oxidative stress. However, several problems are associated with the accurate measurement of these two compounds. We have developed and validated a selective and reproducible high-performance liquid chromatographic method for the quantification of ascorbic acid and dehydroascorbic acid in plasma. The method meets the requirements of a reliable routine analysis. The plasma samples are stabilized with 5 mM metaphosphoric acid, centrifugated at 4 degrees C before HPLC analysis. For ascorbic acid analysis, the sample pH is adjusted to 2.6, whereas for total ascorbic acid measurement dehydroascorbic acid is reduced to ascorbic acid using dithiothreitol for 5 min at pH 6.2 after which the sample pH is adjusted to 2.6. The samples are analyzed on a reversed-phase system using coulometric detection. Dehydroascorbic acid concentrations ae calculated by subtraction. Within- and between-day coefficients of variation for the complete assay were in the range of 4-8 and 3-6% for ascorbic acid and total ascorbic acid, respectively. The stability of ascorbic acid was monitored under various conditions including storage and the implications as well as the reliability of ascorbic acid as a biomarker are discussed.Analytical Biochemistry 09/1995; 229(2):329-35. · 2.58 Impact Factor
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ABSTRACT: To measure the amount of lipid peroxidation and erythrocyte antioxidation in patients undergoing laparoscopic and open cholecystectomy and healthy controls. Non-randomised study. University hospital, Istanbul. 31 patients, of whom 14 underwent open and 17 laparoscopic cholecystectomy, and 15 healthy controls. Heparinised blood samples were taken from the patients immediately after operation and from the healthy controls. Lipid peroxidation index as expressed by thiobarbituric-acid-reactive substances (TBARS) and components of the erythrocyte antioxidant defence system, namely reduced glutathione, reduced glutathione peroxidase (glutathione-Px) and CuZn superoxide dismutase (CuZn SOD) in patients undergoing open or laparoscopic cholecystectomy and healthy controls. All 4 variables were significantly higher in the cholecystectomy groups than in controls (p < 0.001), and laparoscopic cholecystectomy caused significantly less oxidative stress than the open operation (p < 0.001). Both types of cholecystectomy cause oxidative stress and lead to an adaptive antioxidant response in the body. However; both oxidative stress and the antioxidant response are more pronounced after traditional open cholecystectomy.The European Journal of Surgery 10/1999; 165(9):871-4.
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ABSTRACT: This prospective, randomized, and controlled study was designed to investigate the effects of different intraabdominal pressures (IAPs) on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy (LC). Twenty-four patients (12 men, 12 women) who underwent LC at either 10 or 15 mmHg of IAP were randomized into two groups. Repeated blood samples were collected to measure thiobarbituric acid reactive substances (TBARS) levels to assess lipid peroxidation and protein carbonyl content and protein sulfhydryl groups to assess protein oxidation status. Serum protein carbonyls and TBARS levels were found to be increased immediately after desufflation in both study groups when compared to the preoperative levels. On the other hand, protein sulfhydryl levels were found to be decreased in both study groups. Although increases in protein carbonyls and TBARS levels were more prominent in patients who underwent LC at 15 mmHg of IAP, this difference was not statistically significant between both groups. The results suggest that both 15 and 10 mmHg of LAP could lead to an increased oxidative stress response during LC, but no difference was found between the groups.Surgical Endoscopy 12/2003; 17(11):1719-22. · 3.43 Impact Factor