***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: BACKGROUND / AIMS Laparoscopy is advantageous but its adverse effects have not yet been completely eluci date d. Pneumoperitoneum performed to facilitate laparoscopy causes the organ perfusion decrease such as in the intestine . Oxidative stress reflects the tissue injury related to ischemia and reperfusion . We previously showed that laparoscopy causes oxidative stress in intestinal tissues . To assess whether the preconditioning phenomenon could be taken advantage of during laparoscopy we design ed this r and omized , controlled , experimental study with blind outcome assessment . We evaluated the effect of preconditioning , including sequential periods of pneumoperitoneum and desufflation on laparoscopy-induced tissue injury of small bowel with the help of two important markers of oxidative stress , thiobarbituric acid reactive substances and reduced glutathione . METHODOLOGY Forty Sprague-Dawley male rats were used . After anesthesia , an intraperitoneal catheter was inserted . Pneumoperitoneum was created in all except controls , by CO2 insufflation under a pressure of 15 mmHg . The rats were r and omized into the groups below : Group P was subjected to 60 minutes of pneumoperitoneum ; Group P/D was subjected to 60 minutes of pneumoperitoneum followed by 45 minutes of desufflation ; Group IP + P was subjected to 10 minutes of pneumoperitoneum , 10 minutes of desufflation and 60 minutes of pneumoperitoneum ; Group IP + P/D was subjected to 10 minutes of pneumoperitoneum , 10 minutes of desufflation , 60 minutes of pneumoperitoneum and 45 minutes of desufflation ; Group C ( Control ) was subjected to a sham operation , without pneumoperitoneum . Small bowel tissue malondialdehyde and reduced glutathione activities were measured , as applicable , by investigators blinded to the study design . The results were decoded and statistically analyzed with Kruskal-Wallis test . Mann-Whitney U test was used to compare the paired groups . p < 0.05 was considered significant . RESULTS Small bowel tissue malondialdehyde levels were increased , whereas glutathione values were decreased in Groups P and P/D , as compared to Groups PRE/P and PRE/P/D ; the latter two groups had results similar to the Control Group . CONCLUSIONS Laparoscopic preconditioning may reduce the oxidative injury in intestine following laparoscopic procedures Free radicals have been implicated in the pathogenesis of neonatal sepsis and its complications . This study was conducted to determine the changes in the clinical status and the serum levels of lipid peroxidation products [ malondialdehyde ( MDA ) and 4-hydroxylalkenals ( 4-HDA ) ] in 10 septic newborns treated with the antioxidant melatonin given within the first 12 h after diagnosis . Ten other septic newborns in a comparable state were used as “ septic ” controls , while 10 healthy newborns served as normal controls . A total of 20 mg melatonin was administered orally in two doses of 10 mg each , with a 1-h interval . One blood sample was collected before melatonin administration and two additional blood sample s ( at 1 and 4 h ) were collected after melatonin administration to assess serum levels of lipid peroxidation products . Serum MDA + 4-HDA concentrations in newborns with sepsis were significantly higher than those in healthy infants without sepsis ; in contrast , in septic newborns treated with melatonin there was a significant reduction ( p < 0.05 ) of MDA + 4-HDA to the levels in the normal controls at both 1 and 4 h ( p < 0.05 ) . Melatonin also improved the clinical outcome of the septic newborns as judged by measurement of sepsis-related serum parameters after 24 and 48 h. Three of 10 septic children who were not treated with melatonin  died within 72 h after diagnosis of sepsis ; none of the 10 septic newborns treated with melatonin died . To our knowledge , this is the first study where melatonin was given to human newborns BACKGROUND AND PURPOSE Pneumoretroperitoneum ( Prp ) acts as an ischemia/reperfusion ( I/R ) model . Ischemia/reperfusion ( I/R ) injury causes production of reactive oxygen species , which affect organs remote from the sites of I/R. The aim of this study was to assess the remote organ changes after Prp and to explore the effects of antioxidants . MATERIAL S AND METHODS Eighteen adult rabbits were r and omized to three groups , each consisting of six rabbits . Group I ( control ) underwent balloon dissection of the left retroperitoneal space without gas insufflation . In group II ( Prp ) , carbon dioxide at 10 mm Hg was applied for 2 hours after the balloon dissection ( ischemia period ) and for 1 hour after desufflation ( reperfusion period ) . In group III ( Prp + antioxidant ) , 5 minutes before the experiment , verapamil at 0.2 mg/kg was given intravenously and the same procedure was employed as in group II . Hepatic , pulmonary , opposite kidney , and treated kidney malondialdehyde ( MDA ) and reduced glutathione ( GSH ) levels were evaluated to show response to Prp . RESULTS Pneumoretroperitoneum exerted oxidative stress on all tissues with an increase of MDA ( P < 0.05 ) and a decrease of GSH ( P < 0.05 ) . The verapamil-treated group showed lower values of MDA ( P < 0.05 ) and higher values of GSH ( P < 0.05 ) than group II . CONCLUSION Pneumoretroperitoneum increased oxidative stress in all remote organs tested . Verapamil reduced the oxidative stress . We concluded that Prp should be employed carefully in patients with limited vital organ capacity . Verapamil administration may be considered for protection against tissue injury attributable to oxidative stress in these patients Background : Pneumoperitoneum ( P ) created to facilitate laparoscopy ( L ) is associated with splanchnic perfusion , ischemia/reperfusion ( I/R ) injury , and oxidative stress . In this r and omized controlled experimental study with blind outcome assessment , we evaluated the effect of preconditioning ( PRE ) on L-induced I/R injury . Methods : The subjects were 40 Sprague-Dawley male rats .  P was created in all except controls , using carbondioxide ( CO2 ) insufflation under a pressure of 15 mmHg . PRE consisted of 10 min of P , followed by 10 min of deflation ( D ) . The rats were r and omized to the following groups : Group P was subjected to 60 min of P. Group P/D was subjected to 60 min of P , followed by 45 min of D. Group PRE/P was subjected to PRE , followed by 60 min of P. Group PRE/P/D was subjected to PRE , followed by 60 min of P and 45 min of D. Group C ( control ) was subjected to a sham operation , without P. Its anesthesia time was equal to that for group PRE/P/D. At the end of the experiments , the rats were killed ; blood , liver , and kidney sample s were then obtained and coded . Plasma alanine aminotransferase ( ALT ) and malondialdehyde ( MDA ) , as well as homogenized tissue MDA levels and glutathione ( GSH ) activities , were measured ; tissue sample s were assessed for histopathological evidence of injury ; all assessment s were done by investigators blinded to the study design . The results were decoded and analyzed statistically with the Kruskal-Wallis and Mann Whitney tests . A p < 0.05 was considered significant . Results : Plasma ALT as well as plasma , liver , and kidney MDA levels and liver and kidney injury scores were increased , whereas liver and kidney GSH values were decreased in groups P and P/D , as compared to group C. Rats subjected to PRE before P had plasma ALT , kidney MDA , and kidney and liver GSH levels comparable to controls ; their kidney and liver injury scores were higher than controls but significantly lower than nonpreconditioned animals . PRE enabled decreased plasma , kidney , and liver MDA as well as increased kidney GSH if applied before P ; its efficacy on oxidative stress was limited to providing decreased kidney MDA and increased kidney GSH if applied before P/D. However , PRE significantly attenuated kidney and liver injury after P as well as P/D. Conclusion : PRE consisting of 10 min of P followed by 10 min of D decreases the oxidative stress induced by sustained P in the plasma , liver , and kidney . PRE significantly limits liver and kidney injury after prolonged P and P/D. After further studies to define its ideal timing , PRE before L incorporating P may have clinical relevance , especially for elderly patients or those with impaired hepatic and /or renal function or perfusion Background : The aim of this study was to investigate the effect of low-pressure pneumoperitoneum and pentoxifylline , a methylxanthine derivative , in the prevention of injury caused by free oxygen radicals generated during CO2 pneumoperitoneum . Methods : Twenty-eight rabbits were allocated r and omly to 4 groups . Control group rabbits ( group 1 ) were subjected to anesthesia for 60 min ; group 2 and 3 animals were subjected to a CO2 pneumoperitoneum ( 15 or 7 mm Hg ) ; and group 4 rabbits received 50 mg/kg pentoxifylline , followed by a 15-mm-Hg pneumoperitoneum .  Serum alanine aminotransferase ( ALT ) , aspartate aminotransferase ( AST ) , lactate dehydrogenase ( LDH ) , lipid hydroperoxide , glutathione reductase and total antioxidant status were measured . Results : Compared with group 1 , a significant increase in lipid hydroperoxide levels at the end of the pneumoperitoneum and 30 min after deflation and a significant decrease in total antioxidant status 24 h after deflation were recorded in group 2 . In addition , a significant increase was observed in ALT , AST and LDH levels . These changes were attenuated by low-pressure pneumoperitoneum , whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels . Conclusion : Low-pressure pneumoperitoneum could attenuate ischemia/reperfusion injury induced by CO2 pneumoperitoneum in a rabbit model whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels .  Pentoxifylline did not prevent the development of oxidative stress Background Free radical-induced lipid peroxidation associated with a decrease of antioxidant capacity in plasma is observed after the deflation of the pneumoperitoneum in laparoscopic surgery . In this study , we evaluated the effect of the continuous administration of lipid peroxidation derivatives on emulsified propofol . Methods Two groups of 20 patients each who underwent laparoscopic surgery were studied prospect ively . Maintenance of anesthesia was achieved with 66 % nitrous oxide and either isoflurane or continuous propofol administration . The level of thiobarbituric acid-reactive substances ( TBARS ) in the plasma was determined as a measure of free radicals before and after surgery . Results Ten patients in the propofol group had reduced TBARS , as compared to only one in the isoflurane group ( p = 0.003 ) . There was a statistically significant difference in age between the patients with reduced TBARS and those without reduced TBARS ( p=0.009 ) in the propofol group . Conclusions Anesthesia with continuous propofol infusion in laparoscopic surgery has a significant scavenging action on the formation of free radicals and exerts its greatest antioxidant effect in patients ≥48 years of age Objective To determine the effectiveness of early , routine antioxidant supplementation using & agr;-tocopherol and ascorbic acid in reducing the rate of pulmonary morbidity and organ dysfunction in critically ill surgical patients . Summary Background Data Oxidative stress has been associated with the development of the acute respiratory distress syndrome ( ARDS ) and organ failure through direct tissue injury and activation of genes integral to the inflammatory response . In addition , depletion of endogenous antioxidants has been associated with an increased risk of nosocomial infections . The authors postulated that antioxidant supplementation in critically ill surgical patients may reduce the incidence of ARDS , pneumonia , and organ dysfunction . Methods This r and omized , prospect i ve study was conducted to compare outcomes in patients receiving antioxidant supplementation ( & agr;-tocopherol and ascorbate ) versus those receiving st and ard care .  The primary endpoint for analysis was pulmonary morbidity ( a composite measure of ARDS and nosocomial pneumonia ) . Secondary endpoints included the development of multiple organ failure , duration of mechanical ventilation , length of ICU stay , and mortality . Results Five hundred ninety-five patients were enrolled and analyzed , 91 % of whom were victims of trauma . The relative risk of pulmonary morbidity was 0.81 ( 95 % confidence interval 0.60–1.1 ) in patients receiving antioxidant supplementation .  Multiple organ failure was significantly less likely to occur in patients receiving antioxidants  than in patients receiving st and ard care  , with a relative risk of 0.43 ( 95 % confidence interval 0.1 
    Output:
    
All the pharmacological agents , except pentoxifylline , seemed to reduce oxidative stress markers .
However , only mesna pretreatment prevented oxidative stress , because oxidative stress markers remained in the sham levels .
Contrasting data were obtained for pentoxyphilline .
In conclusion , available data suggest that pharmacological modulation of surgical stress response to minimally invasive surgery might be feasible