Roland Istók

Total Aortic Arch Replacement: Superior Ventriculo-Arterial Coupling with Decellularized Allografts Compared with Conventional Prostheses

Background To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts. Methods After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis. Results While Ees did not differ between the groups and over time (4.1±1.19 vs. 4.58±1.39 mmHg/mL and 3.21±0.97 vs. 3.96±1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01±0.67 vs. 6.18±0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03±0.35 vs. 5.99±1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5±50.9 vs. 3.9±23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6±8.3dyn·sec·cm−5 vs. 32.4±2.0dyn·sec·cm−5, P<0.05). Conclusions Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement.

In vitro generation of atrioventricular heart valve neoscaffolds.

Tissue engineering of cardiovascular structures represents a novel approach to improve clinical strategies in heart valve disease treatment. The aim of this study was to engineer decellularized atrioventricular heart valve neoscaffolds with an intact ultrastructure and to reseed them with umbilical cord-derived endothelial cells under physiological conditions in a bioreactor environment. Mitral (n=38) and tricuspid (n=36) valves were harvested from 40 hearts of German Landrace swine from a selected abattoir. Decellularization of atrioventricular heart valves was achieved by a detergent-based cell extraction protocol. Evaluation of the decellularization method was conducted with light microscopy and quantitative analysis of collagen and elastin content. The presence of residual DNA within the decellularized atrioventricular heart valves was determined with spectrophotometric quantification. The described decellularization regime produced full removal of native cells while maintaining the mechanical stability and the quantitative composition of the atrioventricular heart valve neoscaffolds. The surface of the xenogeneic matrix could be successfully reseeded with in vitro-expanded human umbilical cord-derived endothelial cells under physiological flow conditions. After complete decellularization with the detergent-based protocol described here, physiological reseeding of the xenogeneic neoscaffolds resulted in the formation of a confluent layer of human umbilical cord-derived endothelial cells. These results warrant further research toward the generation of atrioventricular heart valve neoscaffolds on the basis of decellularized xenogeneic tissue.

Az emlődaganatok primer szisztémás kemoterápiára adott válasza az immunhisztokémiai fenotípus tükrében

The purpose of the study was to identify breast cancer subtypes by immunohistochemistry likely to respond to neoadjuvant chemotherapy and to analyze the used chemotherapy regimen and the range of response rates. Analysis of a collected database was performed. Ninety-two patients were identified in our files who received neoadjuvant chemotherapy between 1998 and 2009. We used immunohistochemical profiles (ER, PgR, HER2, Ki-67 and p53) of NCB, FNAB and surgical breast specimens to subclassify the tumors. Pathological response rates were assessed following surgical removal of tumors by using the Chevallier classification. DFS and OS was measured in 88 cases from the date of definitive surgery to the date of last follow-up or death. Pathological complete or near-complete remission (pCR = Chevallier I and II) was observed in 13 of 92 cases (14.1%). According to the preoperative characteristics of the 13 tumors achieving pCR, 9 of the cases were triple negative, one of 13 was ER-/HER2+ and three of 13 ER+/HER2+. Twenty-four of 92 patients received taxane based neoadjuvant chemotherapy, 30 of 92 anthracycline based neoadjuvant chemotherapy, 33 of 92 taxane + anthracycline regimen and 2 of 92 CMF regimen. In the taxane treated group of patients the pCR rate was 29.1%, in the anthracycline group 6.6% and in the taxane + anthracycline treated group 12.1%. Concerning DFS, significant difference was observed between the Chevallier III and IV groups (p=0.006), and less events were observed in the pCR group (not significant). pCR was associated with significantly better OS (p=0.050). It seems that even limited, routinely used immunohistochemical profiling of tumors is able to predict the likelihood of pCR to neoadjuvant chemotherapy. Patients with triple negative and HER2-positive cancers are likely to achieve pCR after neoadjuvant chemotherapy.

Immunohistochemical phenotype of breast carcinomas predicts the effectiveness of primary systemic therapy

The purpose of the study was to identify breast cancer subtypes by immunohistochemistry likely to respond to neoadjuvant chemotherapy and to analyze the used chemotherapy regimen and the range of response rates. Analysis of a collected database was performed. Ninety-two patients were identified in our files who received neoadjuvant chemotherapy between 1998 and 2009. We used immunohistochemical profiles (ER, PgR, HER2, Ki-67 and p53) of NCB, FNAB and surgical breast specimens to subclassify the tumors. Pathological response rates were assessed following surgical removal of tumors by using the Chevallier classification. DFS and OS was measured in 88 cases from the date of definitive surgery to the date of last follow-up or death. Pathological complete or near-complete remission (pCR = Chevallier I and II) was observed in 13 of 92 cases (14.1%). According to the preoperative characteristics of the 13 tumors achieving pCR, 9 of the cases were triple negative, one of 13 was ER-/HER2+ and three of 13 ER+/HER2+. Twenty-four of 92 patients received taxane based neoadjuvant chemotherapy, 30 of 92 anthracycline based neoadjuvant chemotherapy, 33 of 92 taxane + anthracycline regimen and 2 of 92 CMF regimen. In the taxane treated group of patients the pCR rate was 29.1%, in the anthracycline group 6.6% and in the taxane + anthracycline treated group 12.1%. Concerning DFS, significant difference was observed between the Chevallier III and IV groups (p=0.006), and less events were observed in the pCR group (not significant). pCR was associated with significantly better OS (p=0.050). It seems that even limited, routinely used immunohistochemical profiling of tumors is able to predict the likelihood of pCR to neoadjuvant chemotherapy. Patients with triple negative and HER2-positive cancers are likely to achieve pCR after neoadjuvant chemotherapy.

Comprehensive examination of somatic oncogene mutation in normal and pathologic thyroid tissues

Az elmult evekben tobb munkacsoportnak sikerult olyan szomatikus mutaciokat (BRAF, NRAS, HRAS, KRAS genekben) es genatrendeződeseket (RET/PTC, PAX8/PPAR-gamma) azonositani, amelyek osszefuggest mutatnak a pajzsmirigydaganatok kialakulasaval. Jelen vizsgalatban 11 szemely 22 (11 koros es 11 betegsegmentes) intraoperativ pajzsmirigy-szovetmintait elemeztek. A RAS gencsalad es a BRAF genek szomatikus egypontos nukleotid polimorfizmusait LigthCycler olvadaspontanalizis-modszerrel, mig a genatrendeződeseket valos idejű polimeraz lancreakcio modszerevel vizsgaltak. A daganatos mintakban 3 BRAF-, 2 NRAS-, 1 HRAS-mutaciot, valamint 1 RET/PTC1 atrendeződest talaltak. Az eredmenyek megerősitik a nemzetkozi adatokat, miszerint ezek az egypontos nukleotidpolimorfizmusok es genatrendeződesek megtalalhatok a daganatos pajzsmirigyszovetekben. Valoszinűsithető, hogy ezen genetikai vizsgalatokkal kiegeszult citologiai vizsgalat segitheti a malignus gobok azonositasat, illetve elkepzelhető, hogy prognosztikai faktorkent el...It is established that numerous somatic oncogene mutation (BRAF, NRAS, HRAS, KRAS) and gene translocations (RET/PTC, PAX8/PPAR-gamma) are associated with the development of thyroid cancer. In this study 22 intraoperative thyroid tissue samples (11 pathologic and 11 normal) were examined. Somatic single nucleotide polymorphisms were analyzed by LigthCycler melting method, while translocations were identified by real-time polymerase chain reaction technique. In tumorous sample 3 BRAF, 2 NRAS and one HRAS mutations were found, as well as one RET/PTC1 translocation. Results confirm international data showing that these oncogene mutations and translocations are linked to thyroid cancer. Cytological examination completed with genetic data may support the diagnosis of thyroid malignancies. In addition, genetic alterations may indicate malignant transformation and may become prognostic factors in future.

PREDICTIVE VALUE OF SOMATIC MUTATIONS FOR THE DEVELOPMENT OF MALIGNANCY IN THYROID NODULES BY CYTOPATHOLOGY

OBJECTIVE The purpose of our prospective longitudinal study was to evaluate the predictive efficacy of genetic testing for malignancies in fine-needle aspiration biopsy samples that are cytologically benign at the time of biopsy. METHODS A total of 779 aspirated cytological samples collected from thyroid nodules of 626 patients were included in a 3-year follow-up study. Consecutive patients with cytologically benign thyroid nodules by the Bethesda System for Reporting Thyroid Cytopathology were enrolled in the study. At enrollment, somatic 1-point nucleotide polymorphisms of BRAF and RAS family genes were tested by melting-point analysis, while RET/PTC and PAX8/PPAR-gamma rearrangements were examined by real-time polymerase chain reaction. The genetic test was considered to be positive if a somatic mutation was found. Malignant cytopathologic diagnoses were confirmed by histopathology. RESULTS In samples collected from 779 thyroid nodules, there were 39 BRAF, 33 RAS mutations, and 1 RET/PTC rearrangements found at the beginning of the study. No PAX8/PPAR-gamma rearrangement was identified. There were 52 malignant thyroid tumors removed during follow-up, out of which 24 contained a somatic mutation. The specificity of the presence of somatic mutations for malignancies was as high as 93.3%, and sensitivity was 46.2%. The negative predictive value of genetic testing reached 96.0%. CONCLUSION Our results show that our set of genetic tests can predict the appearance of malignancy in benign thyroid nodules (at the beginning of follow-up) with high specificity and strong negative predictive value. ABBREVIATIONS BRAF = v-raf murine sarcoma viral oncogene homolog B1 FLUS = follicular lesion of undetermined significance FNAB = fine-needle aspiration biopsy FTC = follicular thyroid carcinoma HRAS = homologous to the oncogene from the Harvey rat sarcoma virus KRAS = homologous to the oncogene from the Kirsten rat sarcoma virus NRAS = first isolated from a human neuroblastoma/neuroblastoma RAS = viral oncogene homolog PAX8 = paired box 8 PCR = polymerase chain reaction PPAR-gamma = peroxisome proliferator-activated receptor gamma PTC = papillary thyroid carcinoma RAS = rat sarcoma RET = rearranged during transfection tyrosine-kinase proto-oncogene SM = somatic mutation SNP = single-nucleotide polymorphism.

Szomatikus onkogén mutációk összehasonlí tó vizsgálata egészséges és tumoros pajzsmirigy-szövetmintákban

Az elmult evekben tobb munkacsoportnak sikerult olyan szomatikus mutaciokat (BRAF, NRAS, HRAS, KRAS genekben) es genatrendeződeseket (RET/PTC, PAX8/PPAR-gamma) azonositani, amelyek osszefuggest mutatnak a pajzsmirigydaganatok kialakulasaval. Jelen vizsgalatban 11 szemely 22 (11 koros es 11 betegsegmentes) intraoperativ pajzsmirigy-szovetmintait elemeztek. A RAS gencsalad es a BRAF genek szomatikus egypontos nukleotid polimorfizmusait LigthCycler olvadaspontanalizis-modszerrel, mig a genatrendeződeseket valos idejű polimeraz lancreakcio modszerevel vizsgaltak. A daganatos mintakban 3 BRAF-, 2 NRAS-, 1 HRAS-mutaciot, valamint 1 RET/PTC1 atrendeződest talaltak. Az eredmenyek megerősitik a nemzetkozi adatokat, miszerint ezek az egypontos nukleotidpolimorfizmusok es genatrendeződesek megtalalhatok a daganatos pajzsmirigyszovetekben. Valoszinűsithető, hogy ezen genetikai vizsgalatokkal kiegeszult citologiai vizsgalat segitheti a malignus gobok azonositasat, illetve elkepzelhető, hogy prognosztikai faktorkent el...It is established that numerous somatic oncogene mutation (BRAF, NRAS, HRAS, KRAS) and gene translocations (RET/PTC, PAX8/PPAR-gamma) are associated with the development of thyroid cancer. In this study 22 intraoperative thyroid tissue samples (11 pathologic and 11 normal) were examined. Somatic single nucleotide polymorphisms were analyzed by LigthCycler melting method, while translocations were identified by real-time polymerase chain reaction technique. In tumorous sample 3 BRAF, 2 NRAS and one HRAS mutations were found, as well as one RET/PTC1 translocation. Results confirm international data showing that these oncogene mutations and translocations are linked to thyroid cancer. Cytological examination completed with genetic data may support the diagnosis of thyroid malignancies. In addition, genetic alterations may indicate malignant transformation and may become prognostic factors in future.

Az emlődaganatok primer szisztémás kemoterápiára adott válasza az immunhisztokémiai fenotípus tükrében@@@Immunohistochemical phenotype of breast carcinomas predicts the eff ectiveness of primary systemic therapy

The purpose of the study was to identify breast cancer subtypes by immunohistochemistry likely to respond to neoadjuvant chemotherapy and to analyze the used chemotherapy regimen and the range of response rates. Analysis of a collected database was performed. Ninety-two patients were identified in our files who received neoadjuvant chemotherapy between 1998 and 2009. We used immunohistochemical profiles (ER, PgR, HER2, Ki-67 and p53) of NCB, FNAB and surgical breast specimens to subclassify the tumors. Pathological response rates were assessed following surgical removal of tumors by using the Chevallier classification. DFS and OS was measured in 88 cases from the date of definitive surgery to the date of last follow-up or death. Pathological complete or near-complete remission (pCR = Chevallier I and II) was observed in 13 of 92 cases (14.1%). According to the preoperative characteristics of the 13 tumors achieving pCR, 9 of the cases were triple negative, one of 13 was ER-/HER2+ and three of 13 ER+/HER2+. Twenty-four of 92 patients received taxane based neoadjuvant chemotherapy, 30 of 92 anthracycline based neoadjuvant chemotherapy, 33 of 92 taxane + anthracycline regimen and 2 of 92 CMF regimen. In the taxane treated group of patients the pCR rate was 29.1%, in the anthracycline group 6.6% and in the taxane + anthracycline treated group 12.1%. Concerning DFS, significant difference was observed between the Chevallier III and IV groups (p=0.006), and less events were observed in the pCR group (not significant). pCR was associated with significantly better OS (p=0.050). It seems that even limited, routinely used immunohistochemical profiling of tumors is able to predict the likelihood of pCR to neoadjuvant chemotherapy. Patients with triple negative and HER2-positive cancers are likely to achieve pCR after neoadjuvant chemotherapy.