Attila Patonai

Semmelweis University, Budapeŝto, Budapest, Hungary

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Publications (18)95.09 Total impact

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    ABSTRACT: Although experimental autologous patch or tubular conduit vascular grafts made from the internal rectus fascia sheath (IRFS) have been reported in the literature, thorough morphological evaluation and verification of the histological arterialisation of such grafts are lacking. Four purpose-bred Beagle dogs were utilised to create eight arterial internal rectus fascia sheath (ARFS) grafts implanted between bisected ends of the external iliac arteries. Four out of the eight ARFS grafts were patent after three months. Haematoxylin-eosin and Azan staining verified that the grafts gained a vessel-like layered structure with the presence of large amounts of collagen fibres. Although the inner surface of the intact IRFS was originally covered with claudin-5-negative and pancytokeratin-positive mesothelial cells in control samples, the internal cells of the ARFS grafts became claudin-5 positive and pancytokeratin negative like in intact arteries. Spindle-shaped cells of the wall of ARFS grafts were α-smooth muscle actin (α-SMA) positive just like the smooth muscle cells of intact arteries, but α-SMA immunoreactivity was negative in the intact IRFS. According to these findings, the fibroblast cells of the ARFS graft have changed into myofibroblast cells. The study has proved that ARFS grafts may be used as an alternative in arterial replacement, since the graft becomes morphologically and functionally similar to the host vessel via arterialisation.
    Acta Veterinaria Hungarica 12/2014; 62(4):429-38. DOI:10.1556/AVet.2014.025 · 0.65 Impact Factor
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    ABSTRACT: Numerous data suggest that altered expression of tight junction proteins such as occludin and claudins plays important role in carcinogenesis. However, little is known about tricellulin, a transmembrane tight junction protein concentrated where three epithelial cells meet. We aimed to characterize tricellulin expression in normal and cirrhotic liver in comparison to primary hepatic neoplasms. Tricellulin expression of 20 control livers, 12 cirrhotic livers, 32 hepatocellular carcinomas (HCC), and 20 intrahepatic cholangiocarcinomas (iCCC) was investigated by immunohistochemistry and Western blotting. Co-localization of tricellulin with claudin-1, -4, and MRP2 was studied using double immunofluorescence. Scattered tricellulin immunopositivity was restricted to biliary pole of hepatocytes confirmed by co-localization with MRP2. Moreover, spotted-like reaction was observed between bile duct epithelial cells. In 40 % of HCCs marked tricellulin overexpression was measured regardless of tumor grades. In iCCCs, however, tricellulin expression decreased parallel with dedifferentiation. In HCCs high tricellulin expression, in iCCCs low tricellulin expression correlated with poor prognosis. Co-localization with MRP2 might substantiate that tricellulin plays role in blood-biliary barrier. Overexpressed tricellulin in a subset of HCCs correlated with unfavorable prognosis. Similar to ductal pancreatic adenocarcinoma, higher grades of iCCCs were associated with decreased tricellulin expression correlating with poor prognosis.
    Pathology & Oncology Research 03/2014; 20(4). DOI:10.1007/s12253-014-9758-x · 1.86 Impact Factor
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    ABSTRACT: Fibrolamellar hepatocellular carcinoma (FLC) occurs in non-cirrhotic liver and the etiopathogenesis is still obscure. Both hepatocellular and cholangiocellular markers are expressed in the tumor, however, molecular alterations and altered pathways playing role in the tumor pathogenesis are not clearly identified. The purpose of the present study was to compare the expression level of EGFR, syndecan-1 and ß-catenin in FLC, conventional hepatocellular carcinoma (cHCC) and cholangiocellular carcinoma (CCC) and to investigate the possibility of mutation both in EGFR and K-RAS. Eight FLCs were compared with 7 cHCCs, 7 CCCs and 5 normal liver samples. Cytokeratins 7, 8, 18, 19, HepPar1 (HSA), EGFR, syndecan-1 (CD138) and ß-catenin were detected by immunohistochemistry. In addition EGFR, ß-catenin and syndecan-1 were evaluated by digital morphometry and K-RAS, EGFR mutations in FLC cases using paraffin-embedded samples. All FLCs were positive for HepPar1 (HSA) and cytokeratins 7, 8, 18, but negative for cytokeratin 19 by immunohistochemistry. EGFR was significantly overexpressed in all three tumor types, being highest in FLCs (p = 0,0001). EGFR, K-RAS mutation analyses revealed no mutations in exons studied in FLCs. Our findings proved that expression of EGFR is higher in FLC than in other types of primary malignant hepatic tumors and no K-RAS mutation can be detected, so FLC is a good candidate for anti-EGFR treatment.
    Pathology & Oncology Research 08/2012; 19(1). DOI:10.1007/s12253-012-9558-0 · 1.86 Impact Factor

  • Journal of Hepatology 04/2012; 56:S295. DOI:10.1016/S0168-8278(12)60764-8 · 11.34 Impact Factor
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    ABSTRACT: Autologous vascular patch grafts developed from the internal rectus sheath were implanted onto the bilateral common iliac vein and jugular vein of 4 experimental beagle dogs. During the development and implanting of the grafts no technical difficulties or perioperative complications were encountered. The follow-up lasted 6 months and 3 months in the case of the common iliac vein grafts and the jugular grafts, respectively. In the postoperative period, the morphological and functional characteristics of the implanted venous sections were examined by Doppler ultrasonography and CT angiography. Normal patency was detected, and none of these check-ups showed obturation or stenosis. The histological survey showed no mesothelial cell layer, but the insides of the grafts showed total restructuring and were covered by a normal endothelial layer. No difference could be detected between samples harvested 3 and 6 months after implanting. The immunohistochemical examinations using anti-claudin-5 and anti-CD31 antibodies confirmed the preliminary results of the histological examinations that the luminal surfaces of the implanted grafts developed a differentiated monolayer endothelium which was free of degenerative and inflammatory signs. The control examinations show the suitability of the internal rectus sheath as a venous wall donor.
    Acta Veterinaria Hungarica 09/2011; 59(3):373-84. DOI:10.1556/AVet.2011.026 · 0.65 Impact Factor
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    ABSTRACT: Fibrolamellar hepatocellular carcinoma is a subtype of hepatocellular carcinoma occurring in non-cirrhotic liver at a younger age. The tumor expresses both hepatocellular and cholangiocellular markers. Previously, our group described overexpression of tight junction protein claudin 4 in cholangiocellular carcinoma in contrast to hepatocellular carcinoma. In the present study, tight junction protein expressions were studied to possibly clarify bipotential lineage of fibrolamellar hepatocellular carcinoma. Eleven fibrolamellar hepatocellular carcinomas were compared with seven "conventional" hepatocellular carcinomas, seven cholangiocellular carcinomas, and five normal liver samples. By immunohistochemistry, all fibrolamellar hepatocellular carcinomas were positive for HepPar1 and cytokeratins 7, 8, and 18, but negative for cytokeratin 19. Glypican-3 gave weak staining in two cases. Expression of claudin 1 was lower, while that of claudin 2 was higher in fibrolamellar hepatocellular carcinomas than in other tumors. Claudins 3, 4, and 7 were not detectable in fibrolamellar hepatocellular carcinomas as in the majority of "conventional" hepatocellular carcinomas, contrary to high expression observed in cholangiocellular carcinomas. Focal or diffuse claudin 5 expression was detected in nine of 11 fibrolamellar hepatocellular carcinomas contrary to other tumors. Tricellulin was significantly downregulated in all tumors compared with normal liver. Our findings showed claudins to exhibit specific expression patterns in fibrolamellar hepatocellular carcinomas not observed in other primary liver tumors, with unique claudin 5 expression and pattern features similar to common hepatocellular carcinoma, but different from cholangiocellular carcinoma. This is the first report describing the loss of tricellulin expression in human hepatic tumors.
    Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 06/2011; 458(6):679-88. DOI:10.1007/s00428-011-1077-y · 2.65 Impact Factor

  • Journal of Hepatology 03/2011; 54. DOI:10.1016/S0168-8278(11)60253-5 · 11.34 Impact Factor
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    ABSTRACT: Vascular complications are major causes of graft failure in liver transplantation. The use of different vascular grafts is common but the results are controversial. The aim of this study was to create an 'ideal' arterial interponate for vascular replacements in the clinical field. An autologous, tubular graft prepared from the posterior rectus fascia sheath was used for iliac artery replacement in dogs for 1, 3, 6 and 12 months. Forty-one grafts were implanted and immunosuppression was used in separate groups. The patency rate was followed by Doppler ultrasound. Thirty-seven grafts remained patent, 2 cases with thrombosis and 2 cases with stenosis occurred. There was no evidence of necrosis or aneurysmatic formation. The histological analysis included conventional light microscopic and immunohistochemical examinations for CD34 and factor VIII. The explanted grafts showed signs of arterialisation, appearance of elastin fibres, and smooth muscle cells after 6 months. Electron microscopy showed intact mitochondrial structures without signs of hypoxia. In conclusion, the autologous graft presents acceptable long-term patency rate. It is easy to handle and the concept of beneficial presence of the anti-clot mesothelium until endothelialisation seems to work. The first clinical use was already reported by our group with more than 2 years survival.
    Acta Veterinaria Hungarica 10/2008; 56(3):411-20. DOI:10.1556/AVet.56.2008.3.14 · 0.65 Impact Factor
  • B Nemes · E Sárváry · L Kóbori · Zs Gerlei · A Patonai · F Perner · V Weszelits · J Járay ·

    Digestive and Liver Disease 02/2005; 37(1):68-9. DOI:10.1016/j.dld.2004.09.004 · 2.96 Impact Factor
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    ABSTRACT: Chlamydia pneumoniae is one of the possible pathogenetic factors of atherosclerotic processes. Foam cell arteriopathy is a generally accepted pathologic feature of chronic liver allograft rejection and has several similarities to the early lesions of atherosclerosis. The aim of the authors' study was to show any existing correlation between the occurrence of Chlamydia pneumoniae and the presence of foam cell arteriopathy in transplanted livers with chronic rejection. Ten liver samples from patients with chronic liver rejection including foam cell arteriopathy and 10 liver samples from healthy individuals were analyzed for the presence of Chlamydia pneumoniae by specific immunohistochemistry and polymerase chain reaction (PCR). Liver samples from two transplant patients with chronic liver rejection without any evidence of foam cell arteriopathy and nine patients with acute liver allograft rejection were also investigated by PCR. In all 10 rejected liver samples, Chlamydia pneumoniae was detected by PCR, whereas only one of the healthy control samples and one of the samples with acute rejection were found to be positive. Immunohistochemistry showed similar results. The positive signals of Chlamydia pneumoniae were localized mainly in the hepatocytes, sinusoidal and perisinusoidal cells, and the cells of portal tracts, whereas most of the altered hepatic arteries showed no or very weak positivity. The results strongly suggest an association between the occurrence of Chlamydia pneumoniae and the presence of foam cell arteriopathy in transplanted livers.
    Transplantation 06/2004; 77(10):1522-8. DOI:10.1016/S0168-8278(01)81016-3 · 3.83 Impact Factor
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    ABSTRACT: Interferon with ribavirin therapy has been proposed for the treatment of hepatitis C recurring in liver transplants. Was to assess the efficacy of standard combination therapy (interferon plus ribavirin) of chronic hepatitis C in transplanted patients with recurrent severe HCV induced chronic hepatitis. 12 patients with HCV-PCR positive reaction (genotype 1b) were treated with the therapy of interferon-alpha-2b (3 MU three times a week) and 800-1000 mg ribavirin daily. Liver biopsy had been done in every patients before and after the treatment. Study endpoints were the end of treatment and the 6 month post-therapy sustained virologic response. At the end of treatment 3 patients were negative for HCV-PCR and all of them had negative reaction after 6 month follow-up period. The results are in a good accordance with treatment of patients with chronic hepatitis C without liver transplantation.
    Orvosi Hetilap 12/2003; 144(48):2367-70.
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    ABSTRACT: Hepatic artery thrombosis is a major cause of graft failure in liver transplantation. Use of donor interponates are common, but results are controversial because of necrosis or thrombosis after rejection. Reperfusion injury, hypoxia and free radical production determinate the survival. The aim of the study was to create an 'ideal' arterial interponate. Autologous, tubular graft lined with mesothelial cells, prepared from the posterior rectus fascia sheath, was used for iliac artery replacement in eight mongrel dogs for six months under immunosuppression. Patency rate was followed by Doppler ultrasound. Eight grafts remained patent and another two are patent after one year. The patency rate was good (median Doppler flow: 370 cm/sec) and there was no necrosis, thrombosis or aneurysmatic formation. The grafts showed viable morphology with neoangiogenesis, appearance of elastin, smooth muscle and endothelial cells. Electron microscopy showed intact mitochondrial structures without signs of hypoxia. Tissue oxygenation was good in all cases with normal (< 30 ng/ml) myeloperoxidase production. In conclusion, this autologous graft presents good long-term patency rate. Viability, arterialisation and low thrombogenicity are prognostic factors indicating usability of the graft in the clinical practice without the risk of rejection. Further investigations such as cell cultures and standardisation are necessary.
    Acta Veterinaria Hungarica 10/2003; 51(4):529-37. DOI:10.1556/AVet.51.2003.4.11 · 0.65 Impact Factor

  • Journal of Hepatology 04/2002; 36:40-40. DOI:10.1016/S0168-8278(02)80120-9 · 11.34 Impact Factor

  • Journal of Hepatology 04/2001; 34:35. DOI:10.1016/S0168-8278(01)80986-7 · 11.34 Impact Factor
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    ABSTRACT: A total of 81 orthotopic liver transplantations were performed on 74 patients between January 1995 and December 1999 at the Department of Transplantation and Surgery of the Semmelweis University in Budapest. Indication for transplantation was liver cirrhosis in 57 cases, 10 patients were transplanted due to fulminant liver failure, while 7 patients underwent transplantation because of liver metastasis of different semimalignant tumours. During the above period, retrospective studies on 205 pre- and posttransplantation liver biopsies, 74 explanted livers, 7 explanted liver grafts and 22 autopsy cases were performed at the First Institute of Pathology and Experimental Cancer Research of the Semmelweis University in Budapest. A number of 116 protocol biopsies (dates as zero time, 7th day, 6th month and 12th month) and 73 non-protocol biopsies (taken due to liver allograft dysfunction) were analysed. Different gradings of acute rejection--characterised by trias of portal inflammation, venous endothelitis and bile duct damage--were detected in 62 cases. Chronic rejection occurred in 7 patients, with 4 cases of vanishing bile duct syndrome and one of the case of foam cell arteriopathy, add to 2 cases of chronic rejection characterized by undetermined bile duct damage. The present study includes the evaluation of 22 autopsy cases according to liver transplantation in Hungary, with the finding that liver allograft insufficiency was the main cause of mortality. Authors conclude that pathomorphological analysis has an important role in relation to liver transplantation.
    Orvosi Hetilap 04/2001; 142(9):435-41.
  • Z Schaff · G Lotz · S Simon · A Patonai · P Sotonyi · B Nemes · A Georgopoulos · W Graninger ·

    Journal of Hepatology 04/2001; 34:43-43. · 11.34 Impact Factor
  • G. Lotz · P. Nagy · A. Patonai · A. Kiss · B. Nemes · F. Szalay · Zs. Schaff ·

    Journal of Hepatology 12/1998; 28:175-175. DOI:10.1016/S0168-8278(98)80884-2 · 11.34 Impact Factor
  • Zs. Schaff · K. Jarmay · A. Szepesi · F. Szalay · A. Patonai · B. Nemes · G. Lotz · J. Lonovics ·

    Journal of Hepatology 12/1998; 28:101-101. DOI:10.1016/S0168-8278(98)80599-0 · 11.34 Impact Factor