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Dive into the research topics where Leonidas Alevizos is active.

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Featured researches published by Leonidas Alevizos.


Obesity Surgery | 2012

Reinforcing the staple line during laparoscopic sleeve gastrectomy: prospective randomized clinical study comparing two different techniques. Preliminary results.

Konstantinos Albanopoulos; Leonidas Alevizos; John Flessas; Evangelos Menenakos; Konstantinos M. Stamou; Joanna Papailiou; Maria Natoudi; George C. Zografos; Emmanuel Leandros

BackgroundSleeve gastrectomy involves the creation of small gastric reservoir based on lesser curvature of the stomach, which is fashioned by a longitudinal gastrectomy that preserves the antrum and pylorus together with its vagal innervation. The main complications in the early postoperative course are bleeding and gastric leak. In order to reduce these complications the staple line can be reinforced in many different ways. The purpose of this study was to randomly compare two different techniques in laparoscopic sleeve gastrectomy (LSG): buttressing the staple line at the gastroesophageal junction (angle of Hiss) with Gore Seamguard and staple-line suturing with PDS 2.0.MethodsBetween July 2009 and July 2010, 90 patients were prospectively and randomly enrolled in the two different techniques of handling the staple line during LSG. Forty-eight of these patients belonged in group A (application of Gore Seamguard) and 42 in group B (application of a continuous suture). Operative and postoperative complications were recorded.ResultsPostoperative leak affected two patients in group A (4.2%) and bleeding occurred in one patient of group A (2%). Total complication rate was 6.2% for group A. No major surgical complication occurred in group B. The differences between the two groups did not reach statistical significance.ConclusionsNo significant difference is evidenced in terms of bleeding and postoperative leak between the two techniques of enhancing the staple line in LSG. Suturing of the staple line may be more time consuming but costs are considerably less.


Surgery | 2011

Thyroid surgery with the new harmonic scalpel: A prospective randomized study

Haridimos Markogiannakis; Panagiotis Kekis; Nikolaos Memos; Leonidas Alevizos; Dimitrios Tsamis; Nikolaos V. Michalopoulos; Emmanuel Lagoudianakis; Konstantinos Toutouzas; Andreas Manouras

BACKGROUND Despite their safety and effectiveness in thyroid surgery, the previous harmonic scalpel instruments are considered large and cumbersome by several surgeons. An innovative technical improvement of the device has been made available since 2008. The objective of this study was to compare the results of total thyroidectomy using the new harmonic scalpel (FOCUS) with that with the previously available device (HARMONIC ACE). METHODS A prospective randomized study of all total thyroidectomies between February and July 2008 was conducted. Patients (n = 90) were randomized to undergo total thyroidectomy with FOCUS (group A, n = 45) or HARMONIC ACE (group B, n = 45). RESULTS No significant differences were identified between the 2 groups in terms of demographics, reoperative thyroid surgery, thyroid gland weight and diameter, pathologic diagnosis, preoperative and postoperative serum PTH and calcium levels, postoperative complications, duration of hospital stay, and final outcome. The mean operative time was less in group A than group B (63 ± 7 min vs 76 ± 8 min, P = .009). CONCLUSION The new harmonic scalpel is a useful adjunct to the armamentarium of the thyroid surgeon. It is safe, effective, and hand friendly, offering great capabilities for delicate tissue grasping and dissection. Use of this device decreased operative time compared with the previously available instrument.


World Journal of Surgery | 2012

Novice Surgeons Versus Experienced Surgeons in Laparoendoscopic Single-Site (LESS) Surgery: A Comparison of Performances in a Surgical Simulator

Leonidas Alevizos; Willem Brinkman; Abe Fingerhut; Emmanuel Leandros

IntroductionDuring the past years, there has been increasing interest in simulation-based training of technical skills especially in laparoscopy. The purpose of this study was to compare the performances of novice and experienced laparoscopic surgeons on a LESS simulator.MethodsThe study recruited 20 surgeons classified into two groups: group NS consisted of ten residents without any laparoscopic experience, and group ES consisted of ten surgeons with experience in conventional laparoscopy (performed >90 laparoscopic cholecystectomies) but without any experience in LESS surgery. Both groups completed a mini-trainee course that included four repetitions of a standardized task of circle pattern cutting (CIRCLE). Time, path length, and economy of movement were measured and compared.ResultsGroup ES presented significantly better time scores than group NS in all four repetitions. Economy of movement did not differ significantly between the two groups, whereas path length was shorter for beginners at the forth effort. Moreover, group ES failed to improve path length and economy of movement scores, whereas group NS improved their performance significantly in these parameters.ConclusionsIt seems that previous laparoscopic experience in conventional laparoscopy may not necessarily be an advantage in all parameters of LESS surgery and the learning process can be longer than expected even for experienced surgeons.


Clinical & Experimental Metastasis | 2014

Breast cancer nodal metastasis correlates with tumour and lymph node methylation profiles of Caveolin-1 and CXCR4

Leonidas Alevizos; Agapi Kataki; Anastasia Derventzi; Ilias Gomatos; Christos Loutraris; Georgia Gloustianou; Andreas Manouras; Manousos M. Konstadoulakis; George C. Zografos

Abstract DNA methylation is the best characterised epigenetic change so far. However, its role in breast cancer metastasis has not as yet been elucidated. The aim of this study was to investigate the differences between the methylation profiles characterising primary tumours and their corresponding positive or negative for metastasis lymph nodes (LN) and correlate these with tumour metastatic potential. Methylation signatures of Caveolin-1, CXCR4, RAR-β, Cyclin D2 and Twist gene promoters were studied in 30 breast cancer primary lesions and their corresponding metastasis-free and tumour-infiltrated LN with Methylation-Specific PCR. CXCR4 and Caveolin-1 expression was further studied by immunohistochemistry. Tumours were typified by methylation of RAR-β and hypermethylation of Cyclin-D2 and Twist gene promoters. Tumour patterns were highly conserved in tumour-infiltrated LN. CXCR4 and Caveolin-1 promoter methylation patterns differentiated between node-negative and metastatic tumours. Nodal metastasis was associated with tumour and lymph node profiles of extended methylation of Caveolin-1 and lack of CXCR4 hypermethylation. Immunodetection studies verified CXCR4 and Caveolin-1 hypermethylation as gene silencing mechanism. Absence of Caveolin-1 expression in stromal cells associated with tumour aggressiveness while strong Caveolin-1 expression in tumour cells correlated with decreased 7-year disease-free survival. Methylation-mediated activation of CXCR4 and inactivation of Caveolin-1 was linked with nodal metastasis while intratumoral Caveolin-1 expression heterogeneity correlated with disease progression. This evidence contributes to the better understanding and, thereby, therapeutic management of breast cancer metastasis process.


Canadian Journal of Surgery | 2012

Review of the molecular profile and modern prognostic markers for gastric lymphoma: How do they affect clinical practice?

Leonidas Alevizos; Ilias P. Gomatos; Spyridon Smparounis; Manousos M. Konstadoulakis; Georgios Zografos

Primary gastric lymphoma is a rare cancer of the stomach with an indeterminate prognosis. Recently, a series of molecular prognostic markers has been introduced to better describe this clinical entity. This review describes the clinical importance of several oncogenes, apoptotic genes and chromosomal mutations in the initiation and progress of primary non-Hodgkin gastric lymphoma and their effect on patient survival. We also outline the prognostic clinical importance of certain cellular adhesion molecules, such as ICAM and PECAM-1, in patients with gastric lymphoma, and we analyze the correlation of these molecules with apoptosis, angiogenesis, tumour growth and metastatic potential. We also focus on the host-immune response and the impact of Helicobacter pylori infection on gastric lymphoma development and progression. Finally, we explore the therapeutic methods currently available for gastric lymphoma, comparing the traditional invasive approach with more recent conservative options, and we stress the importance of the application of novel molecular markers in clinical practice.


International Journal of Hyperthermia | 2015

Lack of significant intraoperative coagulopathy in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) indicates that epidural anaesthesia is a safe option

Odysseus Korakianitis; Telemachos Daskalou; Leonidas Alevizos; Konstantinos M. Stamou; Christos Mavroudis; Christos Iatrou; Theodosia Vogiatzaki; Savvas Eleftheriadis; Antonios Apostolos Tentes

Abstract Purpose: The purpose of this study is to evaluate the fluctuations of coagulation parameters during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) and confirm beyond doubt that epidural anaesthesia is safe with this type of operations. Materials and methods: This is a prospective clinical study of consecutive patients who had cytoreductive surgery and HIPEC. An epidural catheter was inserted into all patients. Peripheral venous blood samples in specific time points of the procedure were tested for complete blood count, prothrombin time (PT), activated partial thromboplastin time (aPTT), international normalised ratio (INR), fibrinogen, D-dimer, and expression of the GpIIb/IIIa platelet receptor. Results: A total of 51 consecutive patients were included in this study. The initial mean (SD) platelet count decreased significantly to a mean of 250.6 (105.4) 109/L (p < 0.001). Fibrinogen levels decreased to 295.9 (127.4) mg/dL (p = 0.009). D-dimer levels increased to 5.3 (3.1) mg/dL (p < 0.001). APTT increased from 30.8 (5.8) s to 35.1 (4.6). The mean INR increased significantly to 1.5 (0.5) (p < 0.001). The total number of GpIIb/IIIa platelet receptors showed no significant variation throughout the measurements and was 72603.2 before HIPEC, 80772.4 during, and 77432.1 after. All the parameters examined, despite significant fluctuations remained in levels that would permit perioperative epidural analgesia. No related complications were recorded. Conclusion: Our results support the belief that epidural analgesia is a safe option in cytoreductive surgery and HIPEC despite certain intraoperative fluctuations in coagulation parameters. It is of major importance to regulate any abnormalities observed during surgery. There are no available data regarding the occurrence of coagulopathy in the post-operative period.


Surgical Endoscopy and Other Interventional Techniques | 2010

Prospective appraisal of a 2-day training course on laparoscopic sleeve gastrectomy: the ELTC experience

Emmanuel Leandros; Ilias P. Gomatos; Manousos M. Konstadoulakis; Evangelos Menenakos; Nikolaos Alexakis; Leonidas Alevizos; Konstantinos Albanopoulos; Panayotis Karagiannakos; Abe Fingerhut

BackgroundThe increasing role of laparoscopic sleeve gastrectomy (LSG) in the treatment of morbid obesity dictates the need for greater acquaintance with this type of surgery. This study was designed to evaluate the impact of a 2-day LSG course and a 4-day laparoscopic bariatric mini-training program on the knowledge and training gained by participating surgeons.MethodsA total of 73 trainees (31 residents and 42 surgeons) completed a question survey immediately after completion of the respective courses. Questions probed demographic data, training experience before and after course completion, evaluation of course content, and operative experience.ResultsAll residents and four of the general surgeons found the laparoscopic bariatric mini-training program to be of value with respect to future professional orientations. Seven surgeons started performing LSGs, while another five surgeons decided to occupy themselves with various types of laparoscopic bariatric procedures. The most useful parts of the course included the identification and treatment of complications, the use of new instrumentation, and surgical demonstrations (video or live), as decided by more than 80% of the participants. On a 1–5 scale, the presentation of novel knowledge was evaluated to be ≥3 by all participants.ConclusionThe 2-day LSG course offered participants high-quality novel knowledge and excellent training quality, and exerted impact on their personal career.


International Surgery | 2015

Hemodynamic Monitoring During Heated Intraoperative Intraperitoneal Chemotherapy Using the FloTrac/Vigileo System.

Christos Mavroudis; Leonidas Alevizos; Konstantinos M. Stamou; Theodosia Vogiatzaki; Savvas Eleftheriadis; Odysseas Korakianitis; Antonios Apostolos Tentes; Christos Iatrou

Cytoreductive surgery with HIPEC has provided a chance for long-term survival in selected patients. However, perioperative management remains a challenge for the anesthesiology team. The aim of this study was to evaluate the changes in hemodynamic parameters during hyperthermic intraperitoneal chemotherapy (HIPEC) using the FloTrac/Vigileo system. Forty-one consecutive patients undergoing cytoreductive surgery and HIPEC were enrolled. Heart rate (HR), esophageal temperature, and cardiac output (CO) steadily increased until the end of HIPEC. In the first half of HIPEC, systolic blood pressure (SBP) and central venous pressure (CVP) increased whereas systemic vascular resistance (SVR) decreased; SVR stabilized in the second half. Diastolic blood pressure (DBP), mean arterial pressure (MAP), and stroke volume (SV) showed no significant variation. Male gender was related to increased CVP, CO, and SV, and decreased SVR; age >55 years was related to increased SBP, and peritoneal cancer index (PCI) was correlated with HR, DBP, and SV. PCI >14 was associated with increased HR and decreased DBP and MAP. American Society of Anesthesiologists score >1 was related to decreased CO and SV. Patients undergoing HIPEC develop a hyperdynamic circulatory state because of the increased temperature, characterized by a steady decrease in SVR and continuous increase in HR and CO. FloTrac/Vigileo system may provide an easy-to-handle, noninvasive monitoring tool.


International Surgery | 2015

Changes in T-Lymphocytes' Viability After Laparoscopic Versus Open Cholecystectomy

Ilias Gomatos; Leonidas Alevizos; Olga Kalathaki; Harilaos Kantsos; Agapi Kataki; Emmanuel Leandros; George C. Zografos; Manousos Konstantoulakis

Laparoscopic surgery results in decreased immune and metabolic stress response compared to open surgery. Our aim was to evaluate the suspension of host immune defense in terms of apoptosis, necrosis, and survival of peripheral T-lymphocytes in patients undergoing laparoscopic versus open cholecystectomy. Apoptosis, necrosis and viability of peripheral T-lymphocytes were measured preoperatively and postoperatively by means of flow cytometry in 27 patients undergoing laparoscopic cholecystectomy and 25 undergoing open cholecystectomy. White cell count, CRP, and serum glucose levels were also measured. Viable peripheral T-lymphocytes were significantly decreased in open cholecystectomy (P = 0.02), while their late apoptotic as well as the overall necrotic rate were significantly increased (P = 0.01 and P < 0.01, respectively). Open cholecystectomy was also associated with lower levels of surviving circulating T-lymphocytes (P = 0.01) and higher percentage of necrotic T lymphocytes (P = 0.03) 24 hours postoperatively compared to laparoscopic cholecystectomy. Serum CRP was increased 24 hours after open cholecystectomy (P = 0.04). All differences failed to sustain more than 48 hours postoperatively. Increased viability and decreased necrosis of circulating T-lymphocytes were observed in laparoscopic cholecystectomy. Necrosis (and not apoptosis) seems to be the predominant pathway of T-lymphocyte death in open cholecystectomy, in a process reaching its peak at 24 hours and further attenuating 48 hours postoperatively.


Pathology Research and Practice | 2014

14-3-3 gene expression exerts isoform-dependent functions in sinonasal pathophysiology

Agapi Kataki; Leonidas Alevizos; Andreas C. Lazaris; Georgia Glustianou; Anastasia Derventzi; Evagelos Giotakis; Manousos M. Konstadoulakis; Ioannis Yiotakis

The expression profiles of 14-3-3β and θ isoforms, known to exert both oncogenic and antiapoptotic effects, were assessed in different entities of nasal pathophysiology. Flow cytometry and immunohistochemistry were used on paraffin-embedded sections of 51 inverted papillomas (IP), 26 nasal polyps (NP), 9 polyps with IP (NPIP) and 10 specimens of normal epithelium (NE). 14-3-3β expression was significantly upregulated in IP as compared with both NP (p=0.015) and NE (p=0.002). 14-3-3β was also increased in NPIP as compared with NE (p=0.008). 14-3-3β cytoplasmic staining was more pronounced in basal cells of the respiratory epithelium although serous glands and the vascular system were often positive as well. High 14-3-3β immunopositivity in IP patients concurred with increased proliferative activity shown by PCNA immunostaining (p=0.04). Expression of 14-3-3θ was also found increased in IP and NPIP patients, compared to NP (p=0.005, p=0.002 respectively) and NE (p=0.004 and p=0.001 respectively). 14-3-3θ cytoplasmic immunopositivity was detected in columnar epithelium, particularly in basal and subluminal cells, whereas no immunoreactivity was observed in NP and NE. Our results demonstrate differential expression of 14-3-3β and θ isoforms in sinonasal pathophysiology, supporting their implication, respectively, in the proliferative and inflammatory process engaged in the formation of IP.

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Emmanuel Leandros

National and Kapodistrian University of Athens

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Andreas Manouras

National and Kapodistrian University of Athens

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Evangelos Menenakos

National and Kapodistrian University of Athens

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George C. Zografos

National and Kapodistrian University of Athens

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Konstantinos Albanopoulos

National and Kapodistrian University of Athens

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Konstantinos M. Stamou

National and Kapodistrian University of Athens

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Haridimos Markogiannakis

National and Kapodistrian University of Athens

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Manousos M. Konstadoulakis

National and Kapodistrian University of Athens

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Maria Natoudi

National and Kapodistrian University of Athens

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