***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: STUDY OBJECTIVE To investigate the effects of peritoneal exposure to carbon dioxide ( CO2 ) on peritoneal microcirculation and free radical scavenger ( FRS ) metabolism , and its role in potential adhesion formation after operative laparoscopy . DESIGN R and omized , controlled study ( Canadian Task Force classification I ) . SETTING University-affiliated hospital . PATIENTS Twenty-eight women undergoing operative laparoscopy for adnexal masses . INTERVENTION For each patient , a 1 x 1-cm sidewall peritoneal flap was excised at the end of laparoscopy and numbered r and omly . Similar flaps obtained from 24 women immediately after entering the abdomen during laparotomy served as controls . MEASUREMENTS AND MAIN RESULTS Changes in glutathione peroxidase ( GSH-Px ) , superoxide dismutase ( SOD ) , catalase ( CAT ) , and glutathione ( GSH ) levels were studied in homogenized peritoneal tissues . The duration of CO2 exposure and amount of CO2 used were correlated with levels of free radical scavengers and compared with controls . Mean CO2 exposure , amount of CO2 used , and CO2 pressure ( 15 mm Hg ) was similar between low irrigation and irrigated laparoscopy ( 118.3 + /- 25 and 39.2 + /- 8.81 min and 125 + /- 20 and 44.5 + /- 6.81 min , respectively ) . The change in FRS levels was significantly correlated with duration and amount of CO2 exposure ( r = -0.92 ) . Levels of GSH-Px , SOD , CAT , and GSH were significantly lower in the CO2 exposure group than in controls ( 0.57 micro mol , 1.8 ng , 48.5 micro mol , 1.5 nmol vs 0.8 micro mol , 2.6 + /- 0.4 ng , 79 micro mol , 3.6 nmol , respectively ) . CONCLUSION Exposure to CO2 has adverse effects on peritoneal microcirculation and cell-protective systems , which are proposed mechanisms in adhesion formation . Avoiding long CO2 exposure and copiously irrigating the abdominal cavity throughout surgery may lessen these effects . The potential role of the peritoneal FRS system on postoperative adhesion formation and its relation to estrogen status m and ates further studies Three groups of 11 New Zeal and women each received , for 32 wk , yeast tablets with no added selenium ( placebo ) or 200 micrograms Se/d in tablets either as selenate or as selenium-enriched yeast ( SeMet ) in a double-blind selenium trial . Plasma and erythrocyte ( RBC ) sample s were collected bimonthly . Gel filtration of plasma from women taking SeMet  revealed two major selenium-containing peaks with most of the selenium in the second peak . In contrast , the first peak contained most of the selenium in plasma from women taking  selenate . Chromatography of RBC lysates indicated that the majority of the selenium was with hemoglobin ( Hb ) in women taking SeMet but was about equally distributed between glutathione peroxidase ( GSH-Px ) and Hb in women taking selenate . The percentage of selenium associated with GSH-Px was found to be greater in RBCs and plasma of women taking  selenate  than of those taking SeMet In this prospect i ve study the free radical mediated reactions , the changes of endogenous antioxidant defense mechanism and activation of leukocytes were measured from the blood of patients undergoing elective cholecystectomy because of symptomatic cholecystolithiasis . The patients were r and omised into two groups . Group one contained 21 patients treated by open cholecystectomy(OC ) .  Group two consisted of 21 patients treated by laparoscopic cholecystectomy ( LC ) .  Both groups had similar patient characteristics . Patients with acute cholecystitis , pancreatitis , choledocholithiasis or other disease were excluded . Values from patients in both groups were compared . The measured biochemical parameters are the following : malondialdehyde ( MDA ) as a marker of the free radical induced lipid peroxidations , reduced and oxidised glutathione ( GSH-GSSG ) , as endogenous scavengers as well as markers of oxidative stress and myeloperoxidase activity ( MPO ) of leukocytes . The results showed significantly lower values of postoperatively measured MDA , GSH-GSSG , and MPO activity of leukocytes in patients with laparoscopic cholecystectomy , indicating a lesser stress response and tissue trauma in this group of patients . The results correspond to the favourable results of most other trials evaluating clinical aspect of LC The  patient ’s position during laparoscopic surgery  can have a clinical ly relevant effect on lower limb and splanchnic circulation ; this factor has not yet been investigated with respect to oxidative stress markers . In order to assess this effect , a prospect i ve clinical trial was design ed wherein 2 groups of patients were studied . In group A , 15 patients underwent upper abdominal nonhepatobiliary operations ( 13 modified Nissen fundoplications and 2 Taylor vagotomies )  in the head-up position . In group B , 15 patients underwent lower abdominal operations ( 10 laparoscopic colectomies and 5 inguinal hernia repairs ) in the head-down position . The pneumoperitoneum was maintained at 14 mm Hg in all cases . Plasma concentrations of thiobarbituric-acid reactive substances ( TBARS ) , a marker of lipid peroxidation , plasma total antioxidant status ( TAS ) , and serum uric acid concentrations were measured preoperatively , 5 minutes after deflation of the pneumoperitoneum , and 24 hours postoperatively . Aspartate aminotransferase ( AST ) and alanine aminotransferase ( ALT ) serum activities were measured preoperatively and 24 hours postoperatively . In group A , there was a significant increase in TBARS levels ( p<0.005 ) immediately after deflation of the pneumoperitoneum and a significant decrease in TAS and uric acid levels ( p<0.005 ) in the first postoperative day . There was also a significant postoperative elevation in both ALT and AST activities ( p<0.001 ) . In group B , no significant increase was found in postoperative TBARS or transaminase levels . TAS and uric acid levels decreased significantly in the first postoperative day ( p<0.05 ) and ( p<0.005 , respectively ) . In conclusion , these results show that a combination of pneumoperitoneum and the head-up position causes significant increase in lipid peroxidation , decrease in plasma TAS , and increase in transaminases . The mechanism responsible for these events could be the low-flow ischemia-reperfusion syndrome induced by the pneumoperitoneum and aggravated by the head-up position Background and objective : To compare the effects of sevoflurane and desflurane anaesthesia on lipid peroxidation . Methods : We studied 40 healthy patients undergoing elective laparoscopic cholecystectomy . Patients were r and omly allocated to be anaesthetized either with sevoflurane ( n = 20 ) or desflurane ( n = 20 ) . Anaesthesia was maintained with inspiratory concentrations of sevoflurane 1 - 1.5 MAC ( n = 20 ) or desflurane ( n = 20 ) . Sample s were taken for plasma malondialdehyde and superoxide dismutase assays before induction of anaesthesia , before skin incision and at the end of surgery . Alveolar cell sample s were obtained from the lungs using the technique of protective blind bronchoalveolar lavage , after induction of anaesthesia and at the end of surgery for malondialdehyde and superoxide dismutase concentrations . Results : Plasma malondialdehyde increased more after the administration of desflurane than after sevoflurane : after induction 5.9 ± 0.6 nmol mL−1 for desflurane vs. 3.8 ± 0.5 nmol L−1 for sevoflurane ( P < 0.001 ) ; at the end of the surgery : 6.7 ± 0.4 nmol mL−1 for desflurane vs. 4.2 ± 0.3 nmol mL−1 for sevoflurane ( P < 0.001 ) . There was a small but significant increase in plasma superoxide dismutase concentration after desflurane - from 24.2 ± 1.2 to 24.9 ± 0.9 U mL−1 after induction and 25 ± 1 U mL−1 at the end of the surgery ( P < 0.01 ) - but no increase with sevoflurane . Malondialdehyde concentrations increased significantly in the cells obtained by protective blind bronchoalveolar lavage at the end of surgery in the desflurane group ( from 0.3 ± 0.1 to 1.7 ± 0.2 nmol mL−1 ( P < 0.001 ) ) , but not in the sevoflurane group . There were no significant differences between the two anaesthetics in the amounts of superoxide dismutase in the sample s obtained by protective blind bronchoalveolar lavage . Conclusions : Desflurane may cause more systemic and regional lipid peroxidation than sevoflurane during laparoscopic cholecystectomy in healthy human beings BACKGROUND The aim of this work was to determine and compare plasma levels of proinflammatory cytokines ( IL-1beta , IL-6 and TNF-alpha ) , C-reactive protein ( CRP ) and lipoperoxides in patients su bmi tted to laparoscopic cholecystectomy under general anesthesia or regional anesthesia .  METHODS Two groups of 15 patients of both sexes were su bmi tted to laparoscopic cholecystectomy either with general or regional anesthesia .  In all cases we obtained three sample s of plasma . The first sample was collected immediately before surgery , whereas the other sample s were collected 60 min and 24 h after the cholecystectomy . Using commercial kits , plasma levels of IL-1beta , IL-6 and TNF-alpha were quantified by ELISA , whereas lipoperoxides were determined by a colorimetric method . The ultrasensitive CRP was determined in the hospital by the Prestige 24I automated method . RESULTS In all determinations , proinflammatory cytokines increased 24 h after surgery except plasma levels of IL-1beta in the regional anesthesia group . Comparison of the two different groups showed that the general anesthesia group had a similar or higher quantity of proinflammatory cytokines and oxidative stress when compared to the regional anesthesia group ( p < 0.05 ) . In contrast , plasma levels of CRP were lower in the general anesthesia group ( p < 0.005 ) . CONCLUSIONS The type of anesthesia influences in a different manner the secretion of soluble mediators of inflammation . These observations may have important clinical repercussions BACKGROUND Surgical injury is associated with oxidative stress , often due to ischemia/reperfusion injury . During laparoscopy , increased intra-abdominal pressure caused by pneumoperitoneum may cause splanchnic ischemia followed by reperfusion due to deflation . We measured several markers of oxidative stress in patients undergoing laparoscopic cholecystectomy ( LC ) versus open cholecystectomy ( OC )  to find if these surgical procedures result in different patterns of oxidative stress . METHODS This prospect i ve study enrolled 43 patients with symptomatic cholelithiasis , of whom 21 underwent open , and 22 laparoscopic , cholecystectomy . Twenty healthy adults comprised the control group .  Total antioxidant status ( TAS ) , superoxide dismutase ( SOD ) , endogenous peroxide level ( POX ) , oxidized low density lipoprotein ( oLDL ) autoantibodies ( oLAb ) , and neopterin were measured preoperatively and on postoperative days 1 , 3 , and 7 . RESULTS POX values decreased significantly on postoperative day 1 in the OC ( P<0.01 ) , but not in the LC , group . On postoperative day 7 , POX values were higher than preoperatively in both groups ( P<0.01 ) with no difference between the LC and OC groups . Significant postoperative elevations of oLAb and neopterin levels were observed only on postoperative day 7 in the OC group . There were no changes of oLAb and neopterin levels in the LC group . TAS and SOD levels did not change after either LC or OC . CONCLUSION Cholecystectomy , either open or laparoscopic , caused only moderate oxidative stress . Open cholecystectomy caused changes of oLAb and neopterin , suggesting more severe oxidative stress , and a possible role of reactive oxygen species in the healing of the laparotomic wound Background : Although it has been been shown that the elevation of abdominal pressure causes splanchnic ischemia , the pathophysiological changes that occur during laparoscopic cholecystectomy are still under investigation . Our aim was to evaluate the changes in nitric oxide ( NO ) , malondialdehyde ( MDA ) , and gastric intramucosal pH ( pHi ) during laparoscopic surgery to verify whether splanchn 
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However , results were highly discordant with some studies suggesting less pronounced OS after laparoscopic surgery , other studies suggesting potentiation of OS after laparoscopic surgery and some studies demonstrating no difference in OS between open and laparoscopic surgery