| 1. |
- Björnsson, Bergthor, et al.
(författare)
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Conventional, but not remote ischemic preconditioning, reduces iNOS transcription in liver ischemia/reperfusion
- 2014
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Ingår i: World Journal of Gastroenterology. - : Baishideng Publishing Group Co. Limited. - 1007-9327 .- 2219-2840. ; 20:28, s. 9506-9512
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To study the effects of preconditioning on inducible nitric oxide synthase (iNOS) and interleukin 1 (IL-1) receptor transcription in rat liver ischemia/reperfusion injury (IRI). METHODS: Seventy-two male rats were randomized into 3 groups: the one-hour segmental ischemia (IRI, n = 24) group, the ischemic preconditioning (IPC, n = 24) group or the remote ischemic preconditioning (R-IPC, n = 24) group. The IPC and R-IPC were performed as 10 min of ischemia and 10 min of reperfusion. The iNOS and the IL-1 receptor mRNA in the liver tissue was analyzed with real time PCR. The total Nitrite and Nitrate (NOx) in continuously sampled microdialysate (MD) from the liver was analyzed. In addition, the NOx levels in the serum were analyzed. RESULTS: After 4 h of reperfusion, the iNOS mRNA was significantly higher in the R-IPC (Delta Ct: 3.44 +/- 0.57) group than in the IPC (Delta Ct: 5.86 +/- 0.82) group (P = 0.025). The IL-1 receptor transcription activity was reduced in the IPC group (Delta Ct: 1.88 +/- 0.53 to 4.81 +/- 0.21), but not in the R-IPC group, during reperfusion (P = 0.027). In the MD, a significant drop in the NOx levels was noted in the R-IPC group (12.3 +/- 2.2 to 4.7 +/- 1.2 mu mol/L) at the end of ischemia compared with the levels in early ischemia (P = 0.008). A similar trend was observed in the IPC group (11.8 +/- 2.1 to 6.4 +/- 1.5 mu mol/L), although this difference was not statistically significant. The levels of NOx rose quickly during reperfusion in both groups. CONCLUSION: IPC, but not R-IPC, reduces iNOS and IL-1 receptor transcription during early reperfusion, indicating a lower inflammatory reaction. NOx is consumed in the ischemic liver lobe.
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| 2. |
- Björnsson, Bergþór, 1975-
(författare)
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Methods to Reduce Liver Ischemia/Reperfusion Injury
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: During the last two decades, liver surgery has expanded enormously, partly due to improved surgical equipment and techniques as well as new and more powerful chemotherapy agents. As the liver is a very well-vascularized organ, there is an inherent risk of bleeding during liver resection. One of the most popular methods employed to reduce this risk is to close the vascular inflow to the liver using the Pringle’s maneuver (PM). However, this procedure has been recognized to cause ischemia/reperfusion injury (IRI) to the future liver remnant (FLR). In cases of extensive resection where the FLR is small and in cases when the liver suffers from chronic diseases, such as cirrhosis, IRI can greatly increase the risk of post-operative liver failure (POLF). Ischemic preconditioning (IPC) and, more recently, remote ischemic preconditioning (R-IPC) are methods that have been employed to reduce IRI.Aim: 1) To compare the effects of IPC and R-IPC in a rat model; 2) to investigate the clinical effect of IPC during modern liver surgery; 3) to investigate the role of the nitric oxide (NO) system in IRI, IPC and R-IPC; and 4) to explore the possible protective effects of nitrite administration before IRI.Methods: A rat model of segmental ischemia followed by 4 hours of reperfusion including microdialysis (μD) was developed from earlier models. The effects of IPC and R-IPC were compared using transaminases and histology as well as continuous μD sampling for glucose, pyruvate, lactate and glycerol. The role of the NO system was examined by serum and μD measurements of NOx as well as tissue measurements of iNOS mRNA and IL-1R mRNA. In study II, patients were randomized to IPC or no IPC prior to liver resection, where intermittent PM was used to decrease bleeding.Results: IPC was more effective in protecting the liver against IRI than R-IPC, as indicated by the levels of transaminases. Lower lactate levels were detected in patients treated with IPC before major liver resections than in controls. IPC reduced iNOS mRNA transcription during reperfusion; this result may be related to the early but not sustained increases in IL-1R transcription observed in the IPC group. Nitrite administered before ischemia reduced AST and ALT levels in the level after 4 hours of reperfusion; in addition, necrosis and glycerol release from the ischemic liver were reduced as well.Conclusion: IPC is more effective than R-IPC in animal models; however, this effect is unlikely to be of clinical importance. NOx decreases in the ischemic liver and the administration of nitrite before ischemia reduces IRI in rats. This may have clinical implications in the future.
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| 3. |
- Björnsson, Bergthor, et al.
(författare)
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Remote or Conventional Ischemic Preconditioning -Local Liver Metabolism in Rats Studied with Microdialysis
- 2012
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Ingår i: Journal of Surgical Research. - : Elsevier. - 0022-4804 .- 1095-8673. ; 176:1, s. 55-62
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Tidskriftsartikel (refereegranskat)abstract
- Background. Ischemic preconditioning (IPC) of the liver decreases liver injury secondary to ischemia and reperfusion. An attractive alternative to IPC is remote ischemic preconditioning (R-IPC), but these two methods have not previously been compared. Material and Methods. Eighty-seven rats were randomized into four groups: sham operated (n = 15), 1 h segmental ischemia (IRI, n = 24), preceeded by IPC (n = 24), or R-IPC (n = 24) (to the left hindleg). IPC and R-IPC were performed with 10 min ischemia and 10 min of reperfusion. Analyses of liver microdialysate (MD), serum transaminase levels, and liver histology were made. Results. Rats treated with IPC and R-IPC had significantly lower AST, 71.5 (19.6) IU/L respective 96.6 (12.4) at 4 h reperfusion than those subjected to IRI alone, 155 (20.9), P = 0.0004 and P = 0.04 respectively. IPC also had lower ALT levels, 41.6 (11.3) IU/L than had IRI 107.4 (15.5), P = 0.003. The MD glycerol was significantly higher during ischemia in the R-IPC = 759 (84) mu M] and the IRI = 732 (67)] groups than in the IPC 514 (70) group, P = 0.022 and P = 0.046 respectively. The MD glucose after ischemia was lower in the IPC group 7.1 (1.2) than in the IRI group 12.7 (1.6), P = 0.005. Preconditioning to the liver caused an direct increase in lactate, glucose and glycerol in the ischemic segment compared with the control segment an effect not seen in the R-IPC and IRI groups. Conclusions. IPC affects glucose metabolism in the rat liver, observed with MD. IPC reduces liver cell injury during ischemic and reperfusion in rats. R-IPC performed over the same length of time as IPC does not have the same effect as the latter on ALT levels and MD glycerol; this may suggest that R-IPC does not offer the same protection as IPC in this setting of rat liver IRI.
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| 4. |
- Nilsson, Johnny, et al.
(författare)
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Work-time profile, blood lactate concentration and rating of perceived exertion in the 1998 Greco-Roman Wrestling World Championship.
- 2002
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Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 20:11, s. 939-45
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine work-time profiles, blood lactate concentrations and perceived exertion among Greco-Roman wrestlers in the 1998 World Championship. Forty-two senior wrestlers from nine nations were studied in 94 matches. Each match was recorded with a video camera (Panasonic AG 455, film rate: 25 Hz) and analysed for duration of work (wrestling) and rest (interrupt) periods. Blood lactate concentration was determined with an electrochemical device (Analox P-LM5) and a rating of perceived exertion scale (Borg) was used to estimate general exertion and exertion in the extremity and trunk muscles. The mean duration of the matches was 427 s (range 324-535 s), with mean durations of work and rest of 317 and 110 s, respectively. The mean periods of work and rest were 37.2 and 13.8 s, respectively. Mean blood lactate concentration was 14.8 mmol x 1(-1) (range 6.9-20.6). The difference in mean blood lactate concentration between the first- and final-round matches was not significant (P > 0.05). Blood lactate concentration was significantly higher (P < 0.04) in matches of long duration than in those of short duration. The mean general rating of perceived exertion for all matches was 13.8 according to the scale used. Most of the wrestlers (53.3%) perceived exertion to be highest in the flexors of the forearm, followed by the deltoids (17.4%) and the biceps brachii muscles (12.0%). In addition to a relatively high rating of perceived exertion in the arm muscles, this indicates a high specific load on the flexor muscles of the forearm.
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| 5. |
- Shen, Yang-mei, et al.
(författare)
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Novel gene hBiot2 is an independent prognostic factor in colorectal cancer patients
- 2012
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Ingår i: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 27:2, s. 376-382
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigated the expression of the novel gene hBiot2 in colorectal cancer (CRC) and its relationships with clinicopathological variables in CRC patients. The expression of hBiot2 in 163 primary CRCs together with the corresponding normal mucosa, 36 liver metastases and 5 colon cancer cell lines was examined using real-time PCR. In situ hybridization (ISH) was performed to evaluate the localization of hBiot2 expression in CRC and normal mucosa. hBiot2 expression at the RNA level was localized in the nucleus of tumor cells and normal epithelial cells. The mean expression of hBiot2 in the CRCs (243.571 +/- 564.569) was higher compared to the normal mucosa (107.252 +/- 413.635, Pandlt;0.0001) and liver metastasis samples (42.002 +/- 40.809, P=0.0002). hBiot2 expression was increased from stages I + II to III (P=0.047), and no difference in the expression was found in stages III and IV (P=0.452). A high value of hBiot2 was associated with a poorer prognosis compared with a low value independently of gender, age, tumor site, stage and differentiation (P=0.007, RR 7.519, 95% Cl 1.729-32.704). Liver metastasis, smaller tumors, non-local recurrence and primary liver surgery alone were associated with a higher value of hBiot2 compared to larger tumors, local recurrence and repeated liver surgery (P=0.003, 0.044 and 0.026, respectively). An inverse relationship was found between hBiot2 expression and the metastatic potential of the colon cancer cell lines. Thus, increased expression of hBiot2 may be an early and interim event in the development of CRC. A higher expression of hBiot2 in primary CRC patients independently indicates a poorer prognosis.
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| 6. |
- Winbladh, Anders, 1966-, et al.
(författare)
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Ischemic Preconditioning Prior to Intermittent Pringles Maneuver in Liver Resections
- 2012
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Ingår i: Journal of Hepato-Biliary-Pancreatic Sciences. - : Springer. - 1868-6982 .- 1868-6974. ; 19:2, s. 159-170
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Tidskriftsartikel (refereegranskat)abstract
- Background: Continuous inflow vascular occlusion during liver resections causes less severe ischemia and reperfusion injury (IRI) if it is preceded by ischemic preconditioning (IP) or if intermittent inflow occlusion is used during the resection. No previous clinical trial has studied the effects of adding IP to intermittent inflow occlusion.Methods: Consecutive patients (n=32) with suspicion of malignant liver disease had liver resections (minimum 2 segments) performed with inflow occlusion 15/5. Half of the patients were randomized to receive IP (10/10). The patients were stratified according to volume of resection and none had chronic liver disease. The patients were followed for 5 days with microdialysis (μD).Results: All patients completed the study and there were no deaths. No differences were seen between the groups regarding demographics or perioperative parameters (bleeding, duration of ischemia, resection volume, complications and serum lab tests). There were no differences in ALT, AST, Bilirubin or PT-INR levels, but μD revealed lower levels of lactate, pyruvate and glucose in the IP group having major liver resections (ANOVA). Nitrite and nitrate levels in μD decreased postoperatively but no differences were seen between the groups. In one patient an elevated μDglycerol curve was seen before the diagnosis of a stroke was made.Conclusions: IP before intermittent vascular occlusion does not reduce the serum parameters used to assess IRI. IP seems to improve aerobic glucose metabolism as the levels of glucose, pyruvate and lactate locally in the liver were reduced compared to controls in patients having resected >3 segments. μD may be used to monitor metabolism locally.
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| 7. |
- Winbladh, Anders, 1966-
(författare)
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Microdialysis in Liver Ischemia and Reperfusion injury
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: New chemotherapy regimens and improvements in surgical technique have increased the number of patients with liver tumours eligible for curative liver resection. There is a significant risk of bleeding during liver surgery, but this risk can be reduced if the portal inflow is temporarily closed; i.e. the Pringles maneuver (PM). If the PM is used, the liver will suffer from ischemia and reperfusion injury (IRI). If the liver remnant is too small or if the patient has chronic liver disease, the IRI may inhibit the regeneration of the liver remnant. The patient may then die from postoperative liver failure. Several strategies have been tried to protect the liver from IRI. For instance can the PM be applied in short intervals or reactive oxygen species can be scavenged by antioxidants. There are no sensitive methods available for studying IRI in patients and little is known how IRI affects the metabolism in the liver. Microdialysis is a technique that allows for continuous sampling of interstitial fluid in the organ of interestAim: To investigate the effects of ischemia and reperfusion on glucose metabolism in the liver using the microdialysis technique.Method: A porcine model of segmental ischemia and reperfusion was developed. The hepatic perfusion and glucose metabolism was followed for 6-8 hours by placing microdialysis catheters in the liver parenchyma (studies I-III). In study IV, 16 patients were randomized to have 10 minutes of ischemic preconditioning prior to the liver resection, which was performed with 15 minutes of ischemia and 5 minutes of reperfusion repetitively until the tumour(s) were resected.Results: During ischemia the glucose metabolism was anaerobic in the ischemic segment, while the perfused segment had normal glucose metabolism. Urea was added in the perfusate of the microdialysis catheters and was found to be a reliable marker of liver perfusion. The antioxidant NAcetylcystein (NAC) improved the hepatic aerobic glucose metabolism in the pig during the reperfusion, shown as reduced levels of lactate and improved glycogenesis in the hepatocytes. This can be explained by the scavenging of nitric oxide by NAC as nitric oxide otherwise would inhibit mitochondrial respiration. Also IP improved aerobic glucose metabolism resulting in lower hepatic lactate levels in patients having major liver resections.Conclusion: Microdialysis can monitor the glucose metabolism both in animal experimental models and in patients during and after hepatectomy. Both NAC and IP improves aerobic glucose metabolism, which can be of value in patients with compromised liver function postoperatively.
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| 8. |
- Winbladh, Anders, et al.
(författare)
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N-acetyl cysteine improves glycogenesis after segmental liver ischemia and reperfusion injury in pigs
- 2012
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 47:2, s. 225-236
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective. N-acetylcysteine (NAC) is an antioxidative molecule known to protect liver tissue from oxygen radical species generated during ischemia and reperfusion (IR). Nutritional and toxicology studies have shown that NAC also improves glucose metabolism and glycogen stores. We hypothesized that NAC improves glycogenesis and that impaired glycogenesis is a key element in IR injury. Material and Methods. In an experimental model, 80 min of segmental liver ischemia was induced in 16 pigs and the reperfusion was followed for 360 min. Eight animals received NAC 150 mg/kg as a bolus injection followed by an infusion of NAC 50 mg/kg/h intravenously. Results. AST and leukocyte density were lower in the NAC-treated animals, unrelated to the glutathione levels or apoptosis. Glycogen stores returned to a higher degree in the NAC-treated animals and microdialysis revealed lower levels of lactate during the reperfusion phase. Nitrite/Nitrate levels in the NAC group were lower in both serum and microdialysates, indicating that NAC scavenges radical nitrosative species. Conclusions. NAC treatment improves glycogenesis after liver IR injury and reduces the level of intraparenchymal lactate during reperfusion, possibly due to the scavenging of radical nitrosative species.
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| 9. |
- Winbladh, Anders, 1966-, et al.
(författare)
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N-Acetylcysteine Improves Glycogenesis after Segmental Liver Ischemia and Reperfusion Injury in Pigs
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: N-Acetylcysteine (NAC) is an antioxidative molecule known to protect liver tissue from oxygen radical species generated during ischemia and reperfusion. Nutritional and toxicology studies have shown that NAC also improves glucose metabolism and glycogen stores. We hypothesized that NAC improves glycogenesis and that impaired glycogenesis is a key element in ischemia-reperfusion injury. Material and Methods: In an experimental model, 80 minutes of segmental liver ischemia was induced in 16 pigs and the reperfusion was followed for 360 minutes. Eight animals received NAC 150 mg/kg as a bolus injection followed by an infusion of NAC 50 mg/kg/h intravenously. Results: AST and leukocyte density were lower in the NAC-treated animals, unrelated to the glutathione levels or apoptosis. Glycogen stores returned to a higher degree in the NAC treated animals and microdialysis revealed lower levels of lactate during the reperfusion phase. Nitrite/Nitrate levels in the NAC group were lower in both serum and microdialysate, indicating that NAC scavenges radical nitrosative species (RNS). Conclusions: NAC treatment improves glycogenesis after liver ischemia and reperfusion injury and reduces the level of intraparenchymal lactate during reperfusion, possibly due to the scavenging of RNS.
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| 10. |
- Winbladh, Anders, et al.
(författare)
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Systematic review of cholecystostomy as a treatment option in acute cholecystitis
- 2009
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Ingår i: HPB. - : Elsevier BV. - 1365-182X. ; 11:3, s. 183-193
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Forskningsöversikt (refereegranskat)abstract
- Objectives: Percutaneous cholecystostomy (PC) is an established low-mortality treatment option for elderly and critically ill patients with acute cholecystitis. The primary aim of this review is to find out if there is any evidence in the literature to recommend PC rather than cholecystectomy for acute cholecystitis in the elderly population. Methods: In April 2007, a systematic electronic database search was performed on the subject of PC and cholecystectomy in the elderly population. After exclusions, 53 studies remained, comprising 1918 patients. Three papers described randomized controlled trials (RCTs), but none compared the outcomes of PC and cholecystectomy. A total of 19 papers on mortality after cholecystectomy in patients aged greater than65 years were identified. Results: Successful intervention was seen in 85.6% of patients with acute cholecystitis. A total of 40% of patients treated with PC were later cholecystectomized, with a mortality rate of 1.96%. Procedure mortality was 0.36%, but 30-day mortality rates were 15.4 % in patients treated with PC and 4.5% in those treated with acute cholecystectomy (P less than 0.001). Conclusions: There are no controlled studies evaluating the outcome of PC vs. cholecystectomy and the papers reviewed are of evidence grade C. It is not possible to make definitive recommendations regarding treatment by PC or cholecystectomy in elderly or critically ill patients with acute cholecystitis. Low mortality rates after cholecystectomy in elderly patients with acute cholecystitis have been reported in recent years and therefore we believe it is time to launch an RCT to address this issue.
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