Borbála Balatonyi

Examination of Protective Effect of Ischemic Postconditioning After Small Bowel Autotransplantation

Ischemia/reperfusion (I/R) injury is a serious condition that results from some surgical procedures, including intestinal transplantation. Ischemic postconditioning is defined as brief periods of reperfusion alternating with reocclusion applied during the early minutes after reperfusion. The objective of this study was to investigate the effect of ischemic postconditioning before small bowel autotransplantation. Total orthotopic intestinal autotransplantation was performed in 30 white domestic pigs. Grafts were stored in cold University of Wisconsin solution for 1, 3, or 6 hours. Duration of reperfusion was 3 hours in all grafts. Before reperfusion, the intestine was postconditioned via 3 cycles of ischemia for 30 seconds and reperfusion for 30 seconds (ischemic postconditioning protocol). Tissue from the small intestine was obtained after laparotomy (control group) and at the end of reperfusion periods. To monitor oxidative stress, tissue concentrations of malondialdehyde and reduced glutathione, and activity of superoxide dismutase were determined at spectrophotometry. Tissue damage on sections stained with hematoxylin- eosin was evaluated using a quantitative method (Scion Image software; Scion Corp, Frederick, Maryland). Our results demonstrated that ischemic postconditioning significantly decreased the reperfusion-ended lipid peroxidation value (mean +/- SEM, 142.0 +/- 7.1 micromol/g vs 125.0 +/- 2.1 micromol/g; P < .05). Moreover, the capacity and activity of endogenous antioxidant protective systems (glutathione 789+/-8.0 micromol/g vs 934 +/- 5.7 micromol/g, and superoxide dismutase 110 +/- 9 IU/g vs 126 +/- 4 IU/g; P < .05) remained higher in the ischemic postconditioning groups compared with tissues without ischemic postconditioning. At quantitative analysis, tissue injury was increased by the duration of cold preservation. The greatest injury was observed in the mucosal and submucosal layers and in the depth of crypts after 6 hours of preservation. Ischemic postconditioning significantly decreased intestinal wall injury in each group (P < .05). It was concluded that ischemic postconditioning before reperfusion mitigated oxidative stress and histologic damage during small bowel autotransplantation.

Ischaemic postconditioning reduces serum and tubular TNF-α expression in ischaemic-reperfused kidney in healthy rats.

OBJECTIVE We studied the protective effects of postconditioning (PS) in healthy and hypercholesterolemic rats after renal ischaemia-reperfusion (IR) injury. We aimed to examine cytokine expression and apoptosis in tissue damage after revascularisation (TNF-α levels in serum and tissue). METHODS Male Wistar rats (n = 32) were divided into four groups. The animals of normal feed groups (NF) were fed with normal rat chow and the cholesterol feed groups (CF) were fed with 1.5% cholesterol containing diet for 8 weeks. Anaesthetized rats underwent a 45-min cross-clamping in both kidney pedicles. Ischaemia was followed by 120-min reperfusion with or without PS protocol (group PS vs. IR). Postconditioning was induced by four intermittent periods of ischaemia-reperfusion of 15-s duration each. Serum cholesterol, triglyceride, urea and creatinine levels were determined. Proinflammation was characterized by the measurement of serum TNF-α. Tissue injury in kidney was determined by formaline-fixed, paraffin-embedded tissue sections. Tissue TNF-α levels were determined by immunohistochemistry. RESULTS Significant elevation was observed in serum TNF-α level after IR injury in normal feed groups, which was reduced by PS. In CF group neither the elevation nor the postconditioning induced reduction were as significant as in the NF groups. In normal feed group PS caused a significant reduction in tissue TNF-α level which was significantly higher in CF. CONCLUSIONS Ischaemic postconditioning proved to be an effective defense against IR in NF groups, but it was ineffective in CF groups in kidney tissue.

Transvaginalis cholecystectomia állatmodellen – kezdeti tapasztalatainkr

INTRODUCTION The Natural Orifice Transluminal Endoscopic Surgery (NOTES) is the newest trend in minimally invasive surgery. Based on clinical experiences, transvaginal cholecystectomy causes less pain and operative stress, requires shorter hospitalization and allows patients to return quicker to normal activity. MATERIALS AND METHODS A transvaginal cholecystectomy was carried out using hybrid technique in animal model first time in Hungary. A 5 mm umbilical trocar was used for preparation of cystic artery and duct, clip application and gallbladder dissection. A transvaginally inserted 10 mm trocar was used for laparoscopic camera to follow the procedure. Gallbladder was fixed and secured with a special curved instrument inserted also transvaginally during the procedure. At the end of procedure the gallbladder was removed transvaginally. RESULTS Six transvaginal cholecystectomies was performed on pigs. The mean time of operations was 78 min (40-145 minutes). During the operations and the follow up period (3 months) no complications and mortality was detected. CONCLUSIONS According to our experiences both procedures can be safely carried out on animal model, but further refinement of devices is necessary.

The role of the inhibition of glutathione-s-transferase in the protective mechanisms of ischemic postconditioning

The antioxidant glutathione-S-transferase (GST) is a crucial determinant of the development of ischaemic-reperfusion (I/R) injury, and plays a pivotal role in the regulation of the mitogen activated protein kinase (MAPK) pathways involved in stress response and apoptosis. The aim of this study was to investigate whether inhibition of GST can abolish the benefit of ischaemic postconditioning (IPoC). A neonatal rat cardiomyocyte cell culture was prepared and divided into 6 groups: (I) control group without treatment; (II) cells exposed to simulated I/R; (III) simulated I/R (sI/R) with IPoC; (IV) ethacrynic acid (EA) alone; (V) sI/R with EA; and (VI) sI/R and IPoC together with EA. Viability of the cells was measured by MTT assay, the quantity of apoptotic cells was assessed by flow cytometry following annexin V-FITC - propidium-iodide double staining. The activation of JNK, p38, ERK/p42-p44 MAPKs, and GSK-3β protein kinase was determined by flow-cytometric assay. GST inhibition markedly increased the apoptosis and decreased the cell viability despite IPoC. The protective effect of IPoC was lost in GST-inhibited groups for all MAPKs and GSK-3β. GST activity is required for the survival of cultured cardiomyocytes under stress conditions. GST inhibition was associated with differential activation of MAP and the protein kinases regulating these pathways in the process of ischaemic postconditioning.

A különböző szilikonbevonatú polipropilén hálók szöveti integrációja

INTRODUCTION/AIM Laparoscopic ventral hernia repair requires a surgical mesh implanted in intraperitoneal position. The combined, double layer meshes are promising in animal models as well as in human practice. The aim of this study was to compare the biological behaviour of two different textured silicone covered polypropylene mesh. MATERIALS AND METHODS 3 × 4 cm big full thickness defect of the abdominal wall was created in New Zealand White rabbits. The defect was covered in 20 animals with a polypropylene mesh with laminar silicone layer on the visceral surface (LSPP), while the remaining 20 cases the defects were covered with a macroporous textured silicone impregnated polypropylene mesh (MSPP). Intraperitoneal adhesion formation and tissue ingrowth in the meshes were investigated. Immunohistochemistry was used to detect proliferation activity (Ki-67), neovascularization (VEGF), and to visualize mesothelial layer (CK) over the mesh. Scanning electron microscopy was used to investigate the visceral surface of the meshes. RESULTS While intraperitoneal adhesion formation showed no difference after 1 week, LSPP mesh induced significantly less adhesions after 21 days. The Ki-67 positivity was significantly lower and the number of the VEGF positive cells increased with time in the MSPP group, this was missing in the LSPP group. The thin neoperitoneum layer was detected over MSPP mesh only with CK antibody. CONCLUSION The material and texture of the mesh are responsible for tissular incorporation which is in accordance with the generated foreign body reaction.

Preconditioning is a method that may reduce the negative side-effect of pneumoperitoneum

Abstract Increased intra-abdominal pressure during laparoscopy leads to hypoxia due to reduced blood flow. Aim of our study was to investigate whether preconditioning can reduce this negative effect of the pneumoperitoneum. Fifty female Wistar rats were used, divided into 5 groups. I: Sham operation (Sham), II: conventional pneumoperitoneum (PP), III: transvaginal pneumoperitoneum (TV), IV: preconditioning for 2.5 minutes in two cycles (Pre 2.5), V: preconditioning for 5 minutes (Pre 5). Malondialdehyde (MDA), reduced glutathione (GSH), sulfhydrylgroup (SH-) concentrations, superoxide-dismutase (SOD) and mieloperoxidase (MPO) activity, and anti-apoptotic pathway marker p-AKT level and inflammatory cytokine TNF-α were measured. SOD activity and GSH concentration were decreased in PP and TV groups comparing to Sham and preconditioning groups. MPO activity was decreased also in PP and TV groups comparing to the Sham group but in the preconditioning groups it has remained high. MDA concentration in plasma was...

A különböző szilikonbevonatú polipropilén hálók szöveti integrációja@@@Tissular incorporation of different silicone covered polypropylene meshes is distinct

INTRODUCTION/AIM Laparoscopic ventral hernia repair requires a surgical mesh implanted in intraperitoneal position. The combined, double layer meshes are promising in animal models as well as in human practice. The aim of this study was to compare the biological behaviour of two different textured silicone covered polypropylene mesh. MATERIALS AND METHODS 3 × 4 cm big full thickness defect of the abdominal wall was created in New Zealand White rabbits. The defect was covered in 20 animals with a polypropylene mesh with laminar silicone layer on the visceral surface (LSPP), while the remaining 20 cases the defects were covered with a macroporous textured silicone impregnated polypropylene mesh (MSPP). Intraperitoneal adhesion formation and tissue ingrowth in the meshes were investigated. Immunohistochemistry was used to detect proliferation activity (Ki-67), neovascularization (VEGF), and to visualize mesothelial layer (CK) over the mesh. Scanning electron microscopy was used to investigate the visceral surface of the meshes. RESULTS While intraperitoneal adhesion formation showed no difference after 1 week, LSPP mesh induced significantly less adhesions after 21 days. The Ki-67 positivity was significantly lower and the number of the VEGF positive cells increased with time in the MSPP group, this was missing in the LSPP group. The thin neoperitoneum layer was detected over MSPP mesh only with CK antibody. CONCLUSION The material and texture of the mesh are responsible for tissular incorporation which is in accordance with the generated foreign body reaction.

Investigation of the Oxidative Stress, the Altered Function of Platelets and Neutrophils, in thePatients with Peripheral Arterial Disease

Ischemia reperfusion injury (I/R) is a relevant problem in case of myocardial infarction (Moens AL, Claeys MJ et al. 2005.), stroke, (Kato H and Kogure K 1999), coronary bypass surgery, (Bakkaloglu C, and Soyagir B, 2006), under thrombolysis, (Krumholz HM and Goldberger 2006), revascularization surgery of lower limb (Arato et al 2006., Laird IR 2003), balloon angioplasty (Weissand A.G. and Zahger AT 1999) and in every cases, when the physiological blood flow in the occluded vessels are restored (Falkensammer J and Oldenburg WA 2006), (Ferencz A et al 2004). Vessel closure and hypoxia can be caused by embolism (thrombus, tumour, fat, foreign body) stenotic arteriopathy, arterial spasm, compression, arterial thrombus, trauma, etc. During the exclusion of a segment of the vessels from the circulation, ischemia and acidosis appeared in the surrounding tissues. In case of the heart, when oxygen supply is inadequate, the respiration shift from aerobic fatty acid consumption and metabolism to anaerobic glycolysis, resulting in a reduced ATP production. The results of hypoxia in the metabolically active tissues (cardiac, skeletal muscle and neuronal tissues) are more profound than in other cell types. The cells are exposed to hypoxia try to adapt to the absence of oxygen, by switching their metabolism from aerobic to anaerobic. Finally this strategy leads to tissue damages and loss of cells too, as it can be seen in acute or chronic occlusive diseases, as well. The measures of the tissue injuries depend on the duration of hypoxia, the mass of tissues are involved, the ATP requirement of the cell types and the blood pressure of the patients. Under hypoxic condition the generations of reactive oxygen species (ROS), such as O2.-, H2O2, are increased. During normoxyc, physiological condition mitochondria generate low level of ROS by the respiratory chain. These are managed by natural antioxidants, such as manganese superoxid dismutase (SOD) in the mitochondria, or copper-zinc SOD in the inter-membrane space in the mitochondria, and in the cytosol, making the dismutation of superoxide anion

Transgastric small bowel resection by using hybrid technique — Experimental study

Abstract Introduction:The Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an abdominal operation carried out with flexible endoscopic instruments and their advanced versions via natural orifices. The NOTES causes theoretically less pain, operative stress, shorter hospitalization, quicker recovery and it is scarless. The aim of this investigation was to evaluate the feasibility and safety of transgastric small bowel resection. Materials and methods: Seven domestic pigs were investigated and entered the study; body weight 25 kg in average. General anesthesia was performed. One trocar was used for laparoscopic observations during gastrotomy and transgastric penetration with the gastroscope, later for assistance with a grasper for manipulation of the bowel loops and for the application of the linear stapling device. Then the needle knife was used to complete a 1.5 cm long incision in the gastric wall. The gastroscope was advanced into the peritoneal cavity and a small bowel loop was identified and ...