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Dive into the research topics where Theodoros P. Vassilakopoulos is active.

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Featured researches published by Theodoros P. Vassilakopoulos.


American Journal of Respiratory and Critical Care Medicine | 2010

Mechanical Ventilation–induced Diaphragm Disuse in Humans Triggers Autophagy

Sabah N. A. Hussain; Mahroo Mofarrahi; Ioanna Sigala; Ho Cheol Kim; Theodoros P. Vassilakopoulos; François Maltais; Ion Bellenis; Rakesh K. Chaturvedi; Stewart B. Gottfried; Peter Metrakos; Gawiyou Danialou; Stefan Matecki; Samir Jaber; Basil J. Petrof; Peter Goldberg

RATIONALE Controlled mechanical ventilation (CMV) results in atrophy of the human diaphragm. The autophagy-lysosome pathway (ALP) contributes to skeletal muscle proteolysis, but its contribution to diaphragmatic protein degradation in mechanically ventilated patients is unknown. OBJECTIVES To evaluate the autophagy pathway responses to CMV in the diaphragm and limb muscles of humans and to identify the roles of FOXO transcription factors in these responses. METHODS Muscle biopsies were obtained from nine control subjects and nine brain-dead organ donors. Subjects were mechanically ventilated for 2 to 4 hours and 15 to 276 hours, respectively. Activation of the ubiquitin-proteasome system was detected by measuring mRNA expressions of Atrogin-1, MURF1, and protein expressions of UBC2, UBC4, and the α subunits of the 20S proteasome (MCP231). Activation of the ALP was detected by electron microscopy and by measuring the expressions of several autophagy-related genes. Total carbonyl content and HNE-protein adduct formation were measured to assess oxidative stress. Total AKT, phosphorylated and total FOXO1, and FOXO3A protein levels were also measured. MEASUREMENTS AND MAIN RESULTS Prolonged CMV triggered activation of the ALP as measured by the appearance of autophagosomes in the diaphragm and increased expressions of autophagy-related genes, as compared with controls. Induction of autophagy was associated with increased protein oxidation and enhanced expression of the FOXO1 gene, but not the FOXO3A gene. CMV also triggered the inhibition of both AKT expression and FOXO1 phosphorylation. CONCLUSIONS We propose that prolonged CMV causes diaphragm disuse, which, in turn, leads to activation of the ALP through oxidative stress and the induction of the FOXO1 transcription factor.


British Journal of Haematology | 2007

Prognostic value of serum free light chain ratio at diagnosis in multiple myeloma

Marie-Christine Kyrtsonis; Theodoros P. Vassilakopoulos; Nicoletta Kafasi; Sotirios Sachanas; Tatiana Tzenou; Argiroula Papadogiannis; Zacharoula Galanis; Christina Kalpadakis; Maria Dimou; Elias Kyriakou; Maria K. Angelopoulou; Maria N. Dimopoulou; Marina P. Siakantaris; Evangelia M. Dimitriadou; Styliani I. Kokoris; Panayiotis Panayiotidis; Gerassimos A. Pangalis

The prognostic value of baseline serum free light chain ratio (sFLCR) was investigated in 94 multiple myeloma (MM) patients. sFLCR was calculated as κ/λ or λ/κ, depending on the patients’ dominating monoclonal light chain. Median baseline sFLCR was 3·57 in κ‐MM patients, 45·09 in λ‐MM. ‘High’ sFLCR (≥ the observed median value for κ‐ and λ‐MM respectively) correlated with elevated serum creatinine and lactate dehydrogenase, extensive marrow infiltration and light chain type MM. The 5‐year disease‐specific survival was 82% and 30% in patients with sFLCR lower than and equal or greater than the median, respectively (P = 0·0001). sFLCR was an independent prognostic factor.


Journal of Clinical Oncology | 2002

CD20 Expression in Hodgkin and Reed-Sternberg Cells of Classical Hodgkin’s Disease: Associations With Presenting Features and Clinical Outcome

George Z. Rassidakis; L. Jeffrey Medeiros; Simonetta Viviani; Valeria Bonfante; Gian Paolo Nadali; Theodoros P. Vassilakopoulos; Ofelia Mesina; Marco Herling; Maria K. Angelopoulou; Roberto Giardini; Marco Chilosi; Christos Kittas; Peter McLaughlin; M. Alma Rodriguez; Jorge Romaguera; Gianni Bonadonna; Alessandro M. Gianni; Giovanni Pizzolo; Gerassimos A. Pangalis; Fernando Cabanillas; Andreas H. Sarris

PURPOSE CD20 can be expressed in Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkins disease (HD), but its clinical significance remains controversial. Therefore, we correlated CD20 expression with presenting features and clinical outcome of untreated patients with classical HD. PATIENTS AND METHODS Patients were eligible if they were previously untreated and human immunodeficiency virus-1 negative, had biopsy-proven classical HD, and if pretreatment paraffin-embedded tumor tissue was available. CD20 expression was determined by immunohistochemistry without knowledge of clinical outcome. A tumor was considered positive if any HRS cells expressed CD20, but other cutoffs for number of CD20-positive HRS were also investigated. RESULTS We identified 598 patients whose median age was 30 years and of whom 55% were male. HRS cells expressed CD20 in 132 (22%) of 598 patients with classical HD. When any percentage of CD20 expression in HRS cells was used as a cutoff, the 5-year failure-free survival (FFS) for positive versus negative tumors was 86% versus 84%, respectively, for 302 patients treated with doxorubicin, bleomycin, vinblastine, and dacarbazine or equivalent regimens (P =.7 by log-rank test), 74% versus 77%, respectively, for 181 patients treated with mitoxantrone, vincristine, vinblastine, and prednisone and radiotherapy (P =.7 by log-rank test), 74% versus 84%, respectively, for 54 patients treated with MOPP (P =.4 by log-rank test), and 77% versus 88% for 53 patients treated only with radiotherapy (P =.5 by log-rank test). The 5-year FFS was not statistically different when cutoffs of 5% up to 50% for CD20-positive HRS cells were used. CONCLUSION CD20 is expressed by HRS cells in 22% of patients with classical HD but is not associated with different FFS after treatment with equivalent regimens.


PLOS ONE | 2009

A novel immunological assay for hepcidin quantification in human serum.

Vasiliki Koliaraki; Martha Marinou; Theodoros P. Vassilakopoulos; Eustathios Vavourakis; Emmanuel Tsochatzis; Gerassimos A. Pangalis; George V. Papatheodoridis; Alexandra Stamoulakatou; Dorine W. Swinkels; George Papanikolaou; Avgi Mamalaki

Background Hepcidin is a 25-aminoacid cysteine-rich iron regulating peptide. Increased hepcidin concentrations lead to iron sequestration in macrophages, contributing to the pathogenesis of anaemia of chronic disease whereas decreased hepcidin is observed in iron deficiency and primary iron overload diseases such as hereditary hemochromatosis. Hepcidin quantification in human blood or urine may provide further insights for the pathogenesis of disorders of iron homeostasis and might prove a valuable tool for clinicians for the differential diagnosis of anaemia. This study describes a specific and non-operator demanding immunoassay for hepcidin quantification in human sera. Methods and Findings An ELISA assay was developed for measuring hepcidin serum concentration using a recombinant hepcidin25-His peptide and a polyclonal antibody against this peptide, which was able to identify native hepcidin. The ELISA assay had a detection range of 10–1500 µg/L and a detection limit of 5.4 µg/L. The intra- and interassay coefficients of variance ranged from 8–15% and 5–16%, respectively. Mean linearity and recovery were 101% and 107%, respectively. Mean hepcidin levels were significantly lower in 7 patients with juvenile hemochromatosis (12.8 µg/L) and 10 patients with iron deficiency anemia (15.7 µg/L) and higher in 7 patients with Hodgkin lymphoma (116.7 µg/L) compared to 32 age-matched healthy controls (42.7 µg/L). Conclusions We describe a new simple ELISA assay for measuring hepcidin in human serum with sufficient accuracy and reproducibility.


Intensive Care Medicine | 2008

Ventilator-induced diaphragm dysfunction: the clinical relevance of animal models

Theodoros P. Vassilakopoulos

Experimental evidence suggests that controlled mechanical ventilation (CMV) can induce dysfunction of the diaphragm, resulting in an early-onset and progressive decrease in diaphragmatic force-generating capacity, called ventilator-induced diaphragmatic dysfunction (VIDD). The mechanisms of VIDD are not fully elucidated, but include muscle atrophy (resulting from lysosomal, calpain, caspase and proteasome activation), oxidative stress, structural injury (disrupted myofibrils, increased numbers of lipid vacuoles, and abnormally small and disrupted mitochondria), myofiber remodeling and mitochondrial dysfunction.The major clinical implication of the VIDD is to limit the use of CMV to the extent possible. Partial (assisted) modes of ventilatory support should be used whenever feasible, since these modes attenuate the deleterious effects of mechanical ventilation on respiratory muscles.


Oncologist | 2012

Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone with or Without Radiotherapy in Primary Mediastinal Large B-Cell Lymphoma: The Emerging Standard of Care

Theodoros P. Vassilakopoulos; Gerassimos A. Pangalis; Andreas Katsigiannis; Sotirios G. Papageorgiou; Nikos Constantinou; Evangelos Terpos; Alexandra Zorbala; Effimia Vrakidou; Panagiotis Repoussis; Christos Poziopoulos; Zacharoula Galani; Maria N. Dimopoulou; Stella I. Kokoris; Sotirios Sachanas; Christina Kalpadakis; Evagelia M. Dimitriadou; Marina P. Siakantaris; Marie-Christine Kyrtsonis; John Dervenoulas; Meletios A. Dimopoulos; John Meletis; Paraskevi Roussou; Panayiotis Panayiotidis; Photis Beris; Maria K. Angelopoulou

UNLABELLED More aggressive treatment approaches (methotrexate, cytarabine, cyclophosphamide, vincristine, prednisone, and bleomycin [the MACOP-B regimen] or consolidation with high-dose therapy and autologous stem cell transplantation) have been considered to be superior to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in patients with primary mediastinal large B-cell lymphoma (PMLBCL). Rituximab-CHOP (R-CHOP) is the standard of care for diffuse large B-cell lymphoma, whereas efficacy in PMLBCL has not been adequately confirmed. PATIENT AND METHODS Seventy-six consecutive PMLBCL patients who received R-CHOP with or without radiotherapy (RT) were compared with 45 consecutive historical controls treated with CHOP with or without RT. Baseline characteristics of the two groups were balanced. RESULTS The rate of early treatment failure was much lower with R-CHOP with or without RT (9% versus 30%; p = .004). The 5-year freedom from progression rate after R-CHOP with or without RT was 81%, versus 48% for CHOP with or without RT (p < .0001). The 5-year event-free survival rates were 80% and 47% (p < .0001) and the 5-year overall and lymphoma-specific survival rates were 89% and 69% (p = .003) and 91% and 69% (p = .001), respectively, with only seven of 76 lymphoma-related deaths. Among R-CHOP responders, 52 of 68 received RT. CONCLUSIONS Based on these results, most patients with PMLBCL appear to be cured by R-CHOP in 21-day cycles with or without RT, which could be the current standard of care. Therefore, the need for more aggressive treatment strategies is questionable unless high-risk patients are adequately defined. Further studies are required to establish the precise role of RT.


Hematological Oncology | 2013

Re-evaluation of prognostic markers including staging, serum free light chains or their ratio and serum lactate dehydrogenase in multiple myeloma patients receiving novel agents

Dimitrios Maltezas; Meletios A. Dimopoulos; Irene Katodritou; Panagiotis Repousis; Anastasia Pouli; Evangelos Terpos; Panayiotis Panayiotidis; Sossana Delimpasi; Evridiki Michalis; Konstantinos Anargyrou; Maria Gavriatopoulou; Aikaterini Stefanoudaki; Tatiana Tzenou; Efstathios Koulieris; Sotiris Sachanas; Maria Dimou; Theodoros P. Vassilakopoulos; Maria K. Angelopoulou; Gerassimos A. Pangalis; Marie-Christine Kyrtsonis

International Staging System (ISS), serum free light chain ratio (sFLCR) and lactate dehydrogenase (LDH) are well known, easily assessed independent prognostic indicators of outcome in multiple myeloma (MM). The purpose of the study was to re‐examine the prognostic contribution of these variables in a multicenter setting with special attention to MM patients treated with autologous stem cell transplantation (ASCT) or novel agents (NA). Three hundred and five symptomatic newly diagnosed MM patients were retrospectively studied. Twenty‐seven per cent, 32% and 41% were in ISS stages 1, 2, and 3, respectively. Fifty‐six per cent of them presented kappa light chain monoclonality; median sFLCR was 27.04 (0.37–1.9 × 105) and 47.97 (0.26–2.3 × 107) for kappa patients and lambda patients, respectively; patients with sFLCR above median constituted the high sFLCR group. Thirty‐one per cent of patients had increased LDH. As first line treatment, 55.7% received conventional treatment and 44.3% NA. After induction, 24% underwent ASCT, whereas 76% received NA at any line, either bortezomib (82.5%), thalidomide (48%) or lenalidomide (27%). When the 305 patients were analyzed together, staging, high sFLCR and abnormal LDH were predictive of survival. The same was true for patients that never received NA, whereas neither high sFLCR nor abnormal LDH constituted adverse factors in patients that received NA frontline. In the last group of patients, no difference was observed between ISS stages 2 and 3. The median 5‐year survival of patients that never received NA versus those who did frontline was 29% vs 47%, 7% vs 52% and 24% vs 40% in patients with abnormal LDH, high sFLCR and ISS stage 3, respectively (p = 0.03, p < 0.00001 and p = 0.035). In conclusion, patients gaining the most from NA are those with an aggressive disease as reflected by advanced stage, abnormal LDH and high sFLCR. In addition, the adverse impact of these three variables is obscured by NA. Copyright


European Respiratory Journal | 2010

C-reactive protein and procalcitonin as predictors of survival and septic shock in ventilator-associated pneumonia

Georgios Hillas; Theodoros P. Vassilakopoulos; P. Plantza; A. Rasidakis; Petros Bakakos

We evaluated the performance of procalcitonin (PCT) and C-reactive protein (CRP) threshold values and kinetics as predictors of ventilator-associated pneumonia (VAP) survival and septic shock development. 45 adult patients with VAP were studied. Serum CRP and PCT levels and the Sequential Organ Failure Assessment (SOFA) score were measured on days 1, 4 and 7 (D1, D4, D7) of VAP and their variations between different days (kinetics) were calculated (ΔPCT, ΔCRP). A multivariate logistic regression model was constructed with either VAP 28-day survival or septic shock development as dependent variables, and PCT values, CRP values, kinetics, age, sex, SOFA and Acute Physiology and Chronic Health Evaluation (APACHE) II score as independent variables. No difference was found in CRP levels between survivors and nonsurvivors. Nonsurvivors had significantly higher PCT levels on D1 and D7. In the multivariate analysis, the only factors predicting VAP survival were ΔPCT7-1 (OR 7.23, 95% CI 0.008–0.468) and ΔCRP7-4 (OR 4.59, 95% CI 0.013–0.824). VAP patients who developed septic shock had significantly higher CRP levels on D1 and D7 and higher PCT levels on D1 and D4. The only factor predicting the development of septic shock was SOFA on D1 (OR 7.44, 95% CI 1.330–5.715). Neither PCT and CRP threshold values nor their kinetics can predict VAP survival or septic shock development.


Blood | 2014

Clonal B-cell lymphocytosis exhibiting immunophenotypic features consistent with a marginal zone origin: is this a distinct entity?

Aliki Xochelli; Christina Kalpadakis; Anne Gardiner; Panagiotis Baliakas; Theodoros P. Vassilakopoulos; Zadie Davis; Evangelia Stalika; George Kanellis; Maria K. Angelopoulou; Neil McIver-Brown; Rachel E. Ibbotson; Sotirios Sachanas; Penelope Korkolopoulou; Anastasia Athanasiadou; Achilles Anagnostopoulos; Helen A. Papadaki; Theodora Papadaki; Kostas Stamatopoulos; Gerassimos A. Pangalis; David Oscier

The biological and clinical significance of a clonal B-cell lymphocytosis with an immunophenotype consistent with marginal-zone origin (CBL-MZ) is poorly understood. We retrospectively evaluated 102 such cases with no clinical evidence to suggest a concurrent MZ lymphoma. Immunophenotyping revealed a clonal B-cell population with Matutes score ≤2 in all cases; 19/102 were weakly CD5 positive and all 35 cases tested expressed CD49d. Bone marrow biopsy exhibited mostly mixed patterns of small B-lymphocytic infiltration. A total of 48/66 (72.7%) cases had an abnormal karyotype. Immunogenetics revealed overusage of the IGHV4-34 gene and somatic hypermutation in 71/79 (89.8%) IGHV-IGHD-IGHJ gene rearrangements. With a median follow-up of 5 years, 85 cases remain stable (group A), whereas 17 cases (group B) progressed, of whom 15 developed splenomegaly. The clonal B-cell count, degree of marrow infiltration, immunophenotypic, or immunogenetic findings at diagnosis did not distinguish between the 2 groups. However, deletions of chromosome 7q were confined to group A and complex karyotypes were more frequent in group B. Although CBL-MZ may antedate SMZL/SLLU, most cases remain stable over time. These cases, not readily classifiable within the World Heath Organization classification, raise the possibility that CBL-MZ should be considered as a new provisional entity within the spectrum of clonal MZ disorders.


Leukemia | 2005

Angiogenesis in Hodgkin's lymphoma : a morphometric approach in 286 patients with prognostic implications

P Korkolopoulou; I Thymara; N Kavantzas; Theodoros P. Vassilakopoulos; Maria K. Angelopoulou; S I Kokoris; E M Dimitriadou; Marina P. Siakantaris; K Anargyrou; P Panayiotidis; A Tsenga; A Androulaki; I A Doussis-Anagnostopoulou; E Patsouris; Gerassimos A. Pangalis

The significance of angiogenesis in Hodgkins lymphoma (HL) is not well defined. The aim of this study was to evaluate various morphometric characteristics of microvessels in lymph node sections of 286 patients with HL at diagnosis and investigate their relationship with clinicopathologic parameters and prognosis. Microvessel density (MVD), total vascular area (TVA) and several size- and shape-related microvascular parameters were quantitated – after anti-CD34 immunohistochemical staining – in the region of most intense vascularization, using image analysis. An increase in microvessel caliber parameters (area, perimeter, major and minor axis length) and a decrease in MVD were noted with increasing stage. An inverse relationship was recorded between MVD and the number of involved sites (NIS) and LDH. In univariate analysis, overall disease-specific survival was adversely affected by MVD and TVA, whereas inferior failure-free survival (FFS) was associated with the presence of more flattened vessel sections. Multivariate analysis disclosed that the extent of angiogenesis (MVD/TVA), age and the NIS independently affected overall survival. Accordingly, FFS was independently linked to the shape of microvessels and albumin levels or the NIS. In conclusion, our data support the view that angiogenesis in HL provides independent prognostic information, requiring the concomitant evaluation of quantitative and qualitative aspects of microvascular network.

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Maria K. Angelopoulou

National and Kapodistrian University of Athens

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Marina P. Siakantaris

National and Kapodistrian University of Athens

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Marie-Christine Kyrtsonis

National and Kapodistrian University of Athens

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Panayiotis Panayiotidis

National and Kapodistrian University of Athens

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Maria N. Dimopoulou

National and Kapodistrian University of Athens

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Penelope Korkolopoulou

National and Kapodistrian University of Athens

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Flora N. Kontopidou

National and Kapodistrian University of Athens

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Charis Roussos

National and Kapodistrian University of Athens

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Styliani I. Kokoris

National and Kapodistrian University of Athens

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