Biomedical subjects

Ebru Serinsöz

Publications and source records attributed to Ebru Serinsöz.

10 recordsLinked to original sources

PubMed2005

Quantitative mRNA expression analysis of co-stimulatory molecules in sequential biopsies from heart allografts.

Allograft-specific T-cell activation requires two signals, "signal one" via the T-cell receptor and "signal two" via costimulatory pathways. Animal models provide promising data that blockade of costimulatory signals can lead to T-cell anergy and tolerance. We analyzed 72 formalin-fixed and paraffin-embedded sequential heart allograft biopsies from 22 patients by quantitative real-time reverse transcriptase-polymerase chain reaction for the mRNA expression of the costimulatory molecules CD28, CD80, CD86, CD40, and CD154. mRNA expression levels were correlated to histological grade and time-point of rejection. mRNA expression of costimulatory molecules predominantly expressed by antigen-presenting cells (CD80, CD86, CD40), correlated with histological grade of cell-mediated acute rejection. Costimulatory molecules were up-regulated not only during rejection episodes early after transplantation, but also at late occurring rejection. The present results suggest a simultaneous and long-term therapeutical blockade of more than one costimulatory pathway for the prevention of repetitive T-cell mediated acute rejection episodes after heart transplantation.

Adult↗

PubMed2005

Local complement C3 expression is upregulated in humoral and cellular rejection of renal allografts.

Evidence on the role of the complement system in transplantation pathology has been accelerated by the discovery of C4d as an in situ marker of antibody-mediated rejection. However, a local or systemic source of complement expression during acute rejection is under discussion. Thus, we quantitatively analyzed local RNA expression of complement component C3 as a pivotal molecule in active humoral and cellular rejection of renal allografts. After laser microdissection, real-time RT-PCR was performed for C3 using RNA extracted from tubuli and glomeruli of 68 paraffin-embedded renal allograft biopsies. Protocol and indication biopsies with signs of humoral and/or cellular rejection were investigated. Quantitative expression analysis of cytokines (IFN gamma, MCP-1, IL2, IL8) potentially influencing local C3 expression was performed. We observed a significant increase in median expression level of C3 mRNA in tubuli of C4d-positive indication biopsies, and in tubuli from indication biopsies with signs of T-cell-mediated cellular rejection. Highest expression levels were found in C4d-positive indication biopsies with signs of cellular rejection. Biopsies with upregulated C3 showed increased IFN gamma expression, suggesting allograft-infiltrating T-cells as potential stimulus for local C3 expression. Therefore, locally synthesized complement component C3 contributes to both humoral and cellular rejection, with tubular epithelial cells being a major source.

Biopsy↗

PubMed2005

Distribution of Bcl-2 gene expression and its prognostic value in non-small cell lung cancer.

The aim of this study was to determine the expression of Bcl-2 gene and prognostic importance of Bcl-2 expression in paraffin embedded blocks of patients diagnosed with non-small cell lung cancer (NSCLC). This study included the retrospective analysis of overall 46 patients diagnosed with NSCLC in our clinic between 1996 and 1999. In 16 (34.8%) patients, the diagnosis was made on biopsy of bronchial mucosa and in 30 (65.2%) patients, on materials obtained by surgical resection (lobectomy and pneumonectomy). We reviewed the sections 4-6 microns in size and stained with Hemotoxylin-Eosine (HE) obtained from paraffin embedded blocks and fixed by 10% formalin. These sections are transferred on to slides covered with poly-L-lysine, then de-paraffinization was made. In all cases, immunohistochemical staining with Bcl-2 antibodies was performed. Positive staining was observed in 9 (19.6%) patients, but not in 37 (80.4%) patients. Out of 32 cases with squamous cell tumor, 8 (25%) were observed to have positive staining in their sections, but 24 (75%) were not so. No staining was observed in 11 cases whose cell type was adenoma and two cases whose cell type was adenosquamos (100%). Staining was present in the section of one case with large cell (100%). Median survival time was 36.6 months in cases in which staining was observed and 6.10 months in cases in which staining was not observed, with a significant difference (p< 0.05). In conclusion, the rate of survival was higher in cases in which staining was present.

Adenocarcinoma↗

PubMed2004

Thrombopoietin receptor (Mpl) expression by megakaryocytes in myeloproliferative disorders.

The thrombopoietin receptor (Mpl) is involved in the pathogenesis of chronic myeloproliferative disorders (CMPD). In this study, we determined Mpl expression by bone marrow cells and megakaryocytes in CMPD by applying laser microdissection, real-time RT-PCR, and immunohistochemistry. Mpl mRNA expression was significantly increased up to 9-fold in total bone marrow cells (p < 0.001) and up to 4-fold in megakaryocytes in chronic myeloproliferative disorders (n = 73) compared to normal controls (n = 26, p = 0.01). Immunohistochemistry revealed heterogeneous Mpl expression by megakaryocytes in CMPD with a stronger accentuation in idiopathic myelofibrosis (IMF) in comparison to polycythaemia vera (PV) and essential thrombocythemia (ET). In addition to megakaryocytes, the erythropoietic lineage was prominently labelled by Mpl antiserum, with considerably stronger staining in polycythaemia vera. We conclude that, in CMPD, megakaryocytes and erythroid cells exhibit increased Mpl expression levels which may contribute to the sustained proliferation of both cell lineages in CMPD.

Adult↗

PubMed2004

Different expression levels of the telomerase catalytic subunit hTERT in myeloproliferative and myelodysplastic diseases.

Telomerase is the enzyme required for the addition of telomeric repeats to the ends of chromosomes and thus for chromosome stability. Most somatic human cells lack telomerase activity because they do not express the telomerase reverse transcriptase (hTERT) gene. In contrast, in almost every neoplasia, cancer cells express hTERT and therefore prevent progressive telomere shortening during each cell division. Consecutively, cancer cells obtain the ability to divide without limits and overcome replicative senescence. Gene expression level of the telomerase catalytic subunit hTERT in normal and neoplastic haematopoiesis has not yet been described. Using a quantitative real-time RT-PCR assay, we analysed the level of hTERT expression in various haematologic stem cell disorders and normal bone marrow. We could demonstrate that hTERT is differentially expressed in various haematologic stem cell disorders with significant higher levels in refractory anemia (RA) and chronic myeloid leukemia (CML) compared to other haematopoietic stem cell disorders and non-neoplastic haematopoiesis which may be used as a prognostic indicator in these entities.

Catalytic Domain↗

PubMed2004

Aberrant expression of insulin-like growth factor-2 (IGF-2) in Philadelphia chromosome negative chronic myeloproliferative disorders.

Philadelphia chromosome negative chronic myeloproliferative disorders (Ph- CMPD) comprise haematopoietic stem cell disorders with currently unknown underlying molecular defect. Insulin-like growth factor 2 (IGF-2) is an imprinted gene that is known to be involved in the regulation of normal cell growth and that is overexpressed by a variety of tumors. The expression of IGF-2 in bone marrow cells is largely unknown. In order to elucidate gene expression level, protein expression pattern, and a potential role of IGF-2 in the pathogenesis of Ph- CMPD, we quantitatively analyzed the expression of the IGF-2 gene in bone marrow cells of 69 cases with Ph- CMPD and 31 control cases by applying real-time RT-PCR. IGF-2 gene expression in idiopathic myelofibrosis (IMF) was significantly increased by up to 11-fold as compared to the control group (P < 0.0001). IMF also expressed higher IGF-2 gene level as compared to essential thrombocythaemia (ET) and polycythaemia vera (PV) (P < 0.0001, P = 0.005, respectively). Paranuclear IGF-2 protein could be demonstrated in IMF, ET, and PV exclusively in megakaryocytes and myeloid progenitor cells in contrast to undetectable IGF-2 protein in control cases. We conclude that overexpression of the IGF-2 gene is a pathogenic feature in IMF. In addition, an abundant translational and post-translational processing could explain the accumulation of IGF-2 protein detectable in all Ph- CMPD entities in contrast to non-neoplastic haematopoiesis. We conclude that IGF-2 represents a new molecular target for evaluation of underlying fundamental pathomechanisms in Ph- CMPD.

Adult↗

PubMed2004

Aberrant expression of beta-catenin discriminates acute myeloid leukaemia from acute lymphoblastic leukaemia.

The role of beta-catenin in epithelial neoplasms has been widely studied whereas current knowledge regarding beta-catenin gene and protein expression in bone marrow cells derived from normal haematopoiesis and clonal haematological disorders is lacking. beta-Catenin gene expression was quantitatively investigated in bone marrow cells derived from clonal haematological disorders [acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL), Philadelphia chromosome-positive chronic myeloid leukaemia (Ph+ CML], Ph- myeloproliferative disorders, n = 96) compared with non-neoplastic haematopoiesis (n = 33) by real-time reverse transcription polymerase chain reaction. Cellular localization of beta-catenin protein was detected by immunocytochemistry. beta-Catenin gene expression was significantly increased in AML compared with ALL cases (P < 0.0001), Ph+ CML (P < 0.0001) and non-neoplastic haematopoiesis (P = 0.019). Immunocytochemistry revealed that, in non-neoplastic haematopoiesis, the granulopoietic lineage as well as megakaryocytes showed membranous and cytoplasmic staining to various degrees along with unlabelled nuclei. Besides haematopoiesis, beta-catenin prominently marked bone marrow vascularity and diverse stroma cells. beta-Catenin gene was inversely expressed in AML and ALL with a lack of protein expression in neoplastic cells in ALL. In contrast, the other haematological disorders under study, except for Ph+ CML, did not show significant alterations of overall beta-catenin gene expression compared with normal bone marrow. These data suggest different regulatory mechanisms in the expression and function of beta-catenin in haematopoietic cells.

Acute Disease↗

PubMed2003

Predictable and efficient retroviral gene transfer into murine bone marrow repopulating cells using a defined vector dose.

OBJECTIVE: Current protocols of retroviral gene transfer into murine hematopoietic stem cells (HSC) result in variable gene transfer efficiency and involve various procedures that are not clinically applicable. We developed and evaluated a reliable transduction protocol that is more related to clinical methods. MATERIALS AND METHODS: HSC were enriched from steady-state bone marrow by magnetic cell sorting (lineage depletion) and cultured in defined serum-free medium containing an improved growth factor cocktail (Flt3-ligand, stem cell factor, interleukin-3, interleukin-11). Cell-free ecotropic retroviral vector particles, generated by transient transfection of human 293T-based packaging cells, were preloaded at defined titers on CH296-coated tissue culture plates, thus largely avoiding serum contamination. These conditions were evaluated in 17 experiments involving 29 transduction cultures and 185 recipient mice. RESULTS: After two rounds of infection, the gene marking rates in cultured mononuclear cells and stem/progenitor cells (Lin(-)c-Kit(+)) were 15 to 85% (53.7%+/-21.7%, n=23) and 30 to 95% (69.8%+/-20.4%, n=17), respectively. Even after one round of infection, gene transfer was efficient (31.2%+/-15.1%, n=12). Using identical conditions, gene transfer rates were highly reproducible. Average transgene expression in reconstituted animals correlated well with pretransplant data. Using a moderate multiplicity of infection, the majority of transduced cells carried less than three transgene copies. In addition, coinfection was possible to establish two different vectors in single cells. CONCLUSION: The protocol described here achieves efficient retroviral transduction of murine bone marrow repopulating cells with a defined gene dosage, largely avoiding procedures that decrease stem cell output and repopulating capacity. This protocol may help to improve the predictive value of preclinical efficiency/toxicity studies for gene therapeutic interventions and basic research.

Animals↗

PubMed2003

The polycythaemia rubra vera-1 gene is constitutively expressed by bone marrow cells and does not discriminate polycythaemia vera from reactive and other chronic myeloproliferative disorders.

Little is known about the expression of the polycythaemia rubra vera-1 (PRV-1) gene in bone marrow cells. To determine the expression level of PRV-1 in the bone marrow, we analysed PRV-1 quantitatively in Polycythaemia vera, other chronic myeloproliferative disorders, and reactive states. We demonstrated that PRV-1 was constitutively expressed in both myeloproliferative and reactive states. We concluded that, rather than an upregulation of the PRV-1 gene in the clonal haematopoiesis of polycythaemia vera, a failure to downregulate PRV-1 in granulocytes emigrating from the bone marrow might be responsible for the increase of transcripts in peripheral cells.

Bone Marrow Cells↗

PubMedDate not supplied

Regional chemotherapy-induced cure for pancreatic head carcinoma.

Pancreatic carcinoma has a devastating prognosis. The only hope for cure for many patients is still surgery while the disease is at the early stages. Chemotherapy (systemic/regional) or radiotherapy has been shown to be helpful in the palliation of the disease but not for cure. We reported a pancreatic head carcinoma, which was cured only by regional chemotherapy. To the best of our knowledge this is the first case in the literature.

Adenocarcinoma↗