317 research outputs found

    Donor and recipient treatment with the Lazaroid U-74006F do not improve post-transplant lung function in swine

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    Objective: U-74006F is the only Lazaroid which is currently in clinical use. A number of experimental studies demonstrate that Lazaroids reduce ischemia/reperfusion injury in various organ systems. We evaluated the effect of U-74006F on reperfusion injury in a large animal model of lung allo-transplantation. Methods: Two different treatment modalities were evaluated and compared with corresponding control groups. Unilateral left lung transplantation was performed in 21 weight-matched pigs (24-31 kg). Donor lungs were flushed with 1.5 l cold (1°C) LPD solution and preserved for 20 h. In group I (n=5), donor animals were pretreated with U-74006F (10 mg/kg i.v.) 20 min before harvest. In addition U-74006F was added to the flush solution (10 mg/l). In group III (n=6), the Lazaroid was given to the donor before flush and to the recipient before reperfusion (3 mg/kg i.v.). Group II and IV (n=5) served as control. One hour after reperfusion, the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), mean pulmonary artery pressure, cardiac output, and gas exchange were assessed during a 5 h observation period. Lipid peroxidation (TBARS) and neutrophil migration (MPO activity) were measured at the end of the assessment in lung allograft tissue. Results: A significant change of TBARS concentration was shown in group III (group III 78.7±4.6 pmol/g vs. group IV 120.8±7.2 pmol/g (P=0.0065) normal lung tissue 41.3±4.2 pmol/g). MPO activity was reduced in group III 3.74±0.25 δOD/mg per min vs. group IV 4.97±0.26 δOD/mg per min (P=0.027), normal lung tissue 1.04±0.27 δOD/mg per min). Pulmonary hemodynamics and gas exchange after reperfusion did not differ between groups. In group I and III, a tendency towards a reduced EVLWI was noted. Conclusion: We conclude that combined treatment of donor and recipient with U-74006F reduces free radical mediated injury in the allograft. However, this intervention did not result in a significant reduction of post-transplant lung edema or improvement of pulmonary hemodynamics. Donor pretreatment alone did not improve lung allograft reperfusion injury. These results indicate that the benefit of U-74006F is too small to consider clinical application in lung transplantatio

    Effect of a short period of warm ischemia after cold preservation on reperfusion injury in lung allotransplantation

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    Objective: A short period of warm ischemia during lung allograft implantation is inevitable. We studied the effect of 2 h of warm ischemia before implantation after 18 h of cold preservation on reperfusion edema and pulmonary hemodynamics in a large animal model. Methods: Left lung transplantation was performed in ten weight-matched pigs (25-31 kg). Donor lungs were flushed with 1.5 l cold (1°C) LPD solution and preserved for 20 h. In Group I (n=5) the grafts were preserved for 20 h at 1°C and topically cooled with ice slush during implantation until reperfusion. In Group II (n=5) lungs were stored at 1°C for 18 h followed by 2 h preservation at room temperature (20°C). Topical cooling was not used during implantation. At 1 h after reperfusion the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), intrathoracic blood volume (ITBV), mean pulmonary artery pressure (PAP) and cardiac output (CO) were assessed during a 4 h observation period. Quantitative myeloperoxidase (MPO) activity and thiobarbituric acid-reactive substance (TBARS) levels as an indicator for lipid peroxidation were determined in allograft tissue samples taken 5 h after reperfusion. Results: In Group II a tendency to improved pulmonary vascular resistance and cardiac output was noted. Surprisingly, lung edema, assessed by EVLWI, did not increase in animals with warm ischemia. Even a tendency to a reduced EVLWI was noted. However, differences between groups did not reach statistical significance. Gas exchange did not differ statistically significant between groups. Conclusion: Our results indicate that a short period of warm ischemia before reperfusion does not lead to increased pulmonary edema. In animals with a short period of warm ischemia before reperfusion, even a tendency to reduced posttransplant lung reperfusion injury was noted. In this model, topical graft cooling during lung implantation did not improve posttransplant graft functio

    Buttressing staples with cholecyst-derived extracellular matrix (CEM) reinforces staple lines in an ex vivo peristaltic inflation model

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science + Business Media, LLC 2008Background - Staple line leakage and bleeding are the most common problems associated with the use of surgical staplers for gastrointestinal resection and anastomotic procedures. These complications can be reduced by reinforcing the staple lines with buttressing materials. The current study reports the potential use of cholecyst-derived extracellular matrix (CEM) in non-crosslinked (NCEM) and crosslinked (XCEM) forms, and compares their mechanical performance with clinically available buttress materials [small intestinal submucosa (SIS) and bovine pericardium (BP)] in an ex vivo small intestine model. Methods - Three crosslinked CEM variants (XCEM0005, XCEM001, and XCEM0033) with different degree of crosslinking were produced. An ex vivo peristaltic inflation model was established. Porcine small intestine segments were stapled on one end, using buttressed or non-buttressed surgical staplers. The opened, non-stapled ends were connected to a peristaltic pump and pressure transducer and sealed. The staple lines were then exposed to increased intraluminal pressure in a peristaltic manner. Both the leak and burst pressures of the test specimens were recorded. Results - The leak pressures observed for non-crosslinked NCEM (137.8 ± 22.3 mmHg), crosslinked XCEM0005 (109.1 ± 14.1 mmHg), XCEM001 (150.1 ± 16.0 mmHg), XCEM0033 (98.8 ± 10.5 mmHg) reinforced staple lines were significantly higher when compared to non-buttressed control (28.3 ± 10.8 mmHg) and SIS (one and four layers) (62.6 ± 11.8 and 57.6 ± 12.3 mmHg, respectively) buttressed staple lines. NCEM and XCEM were comparable to that observed for BP buttressed staple lines (138.8 ± 3.6 mmHg). Only specimens with reinforced staple lines were able to achieve high intraluminal pressures (ruptured at the intestinal mesentery), indicating that buttress reinforcements were able to withstand pressure higher than that of natural tissue (physiological failure). Conclusions - These findings suggest that the use of CEM and XCEM as buttressing materials is associated with reinforced staple lines and increased leak pressures when compared to non-buttressed staple lines. CEM and XCEM were found to perform comparably with clinically available buttress materials in this ex vivo model.Enterprise Irelan

    Several clinical interests regarding lung volume reduction surgery for severe emphysema: meta-analysis and systematic review of randomized controlled trials

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    <p>Abstract</p> <p>Objectives</p> <p>We aim to address several clinical interests regarding lung volume reduction surgery (LVRS) for severe emphysema using meta-analysis and systematic review of randomized controlled trials (RCTs).</p> <p>Methods</p> <p>Eight RCTs published from 1999 to 2010 were identified and synthesized to compare the efficacy and safety of LVRS vs conservative medical therapy. One RCT was obtained regarding comparison of median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS). And three RCTs were available evaluating clinical efficacy of using bovine pericardium for buttressing, autologous fibrin sealant and BioGlue, respectively.</p> <p>Results</p> <p>Odds ratio (95%CI), expressed as the mortality of group A (the group underwent LVRS) versus group B (conservative medical therapies), was 5.16(2.84, 9.35) in 3 months, 3(0.94, 9.57) in 6 months, 1.05(0.82, 1.33) in 12 months, respectively. On the 3<sup>rd</sup>, 6<sup>th </sup>and 12<sup>th </sup>month, all lung function indices of group A were improved more significantly as compared with group B. PaO2 and PaCO2 on the 6<sup>th </sup>and 12<sup>th </sup>month showed the same trend. 6MWD of group A on the 6<sup>th </sup>month and 12<sup>th </sup>month were improved significantly than of group B, despite no difference on the 3<sup>rd </sup>month. Quality of life (QOL) of group A was better than of group B in 6 and 12 months. VATS is preferred to MS, due to the earlier recovery and lower cost. And autologous fibrin sealant and BioGlue seems to be the efficacious methods to reduce air leak following LVRS.</p> <p>Conclusions</p> <p>LVRS offers the more benefits regarding survival, lung function, gas exchange, exercise capacity and QOL, despite the higher mortality in initial three postoperative months. LVRS, with the optimization of surgical approach and material for reinforcement of the staple lines, should be recommended to patients suffering from severe heterogeneous emphysema.</p

    Cell Membrane Modification for Rapid Display of Bi-Functional Peptides: A Novel Approach to Reduce Complement Activation

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    Ischemia and reperfusion of organs is an unavoidable consequence of transplantation. Inflammatory events associated with reperfusion injury are in part attributed to excessive complement activation. Systemic administration of complement inhibitors reduces reperfusion injury but leaves patients vulnerable to infection. Here, we report a novel therapeutic strategy that decorates cells with an anti-complement peptide. An analog of the C3 convertase inhibitor Compstatin (C) was synthesized with a hexahistidine (His6) tag to create C-His6. To decorate cell membranes with C-His6, fusogenic lipid vesicles (FLVs) were used to incorporate lipids with nickel (Ni2+) tethers into cell membranes, and these could then couple with C-His6. Ni2+ tether levels to display C-His6 were modulated by changing FLV formulation, FLV incubation time and FLV levels. SKOV-3 cells decorated with C-His6 effectively reduced complement deposition in a classical complement activation assay. We conclude that our therapeutic approach appears promising for local ex vivo treatment of transplanted organs to reduce complement-mediated reperfusion injury
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