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Dive into the research topics where Nikolaos Machairas is active.

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Featured researches published by Nikolaos Machairas.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2016

Comparison Between Minimally Invasive and Open Pancreaticoduodenectomy: A Systematic Review.

Chrysoula Doula; Ioannis D. Kostakis; Christos Damaskos; Nikolaos Machairas; Dimitrios V. Vardakostas; Themistoklis Feretis; Evangelos Felekouras

Introduction: Minimally invasive approaches (laparoscopic or robotic) are used in various operations. Our aim was to compare them with the open approach in pancreaticoduodenectomy. Methods: We conducted a search for articles published in MEDLINE database comparing minimally invasive (laparoscopic or robotic) with open pancreaticoduodenectomy on June 15, 2014. Results: Our search yielded 136 articles. We excluded 122 articles and we took into consideration 14 (10 for laparoscopic and 4 for robotic pancreaticoduodenectomies). Most cases were related to malignant diseases and tumors treated with minimally invasive operations tended to be smaller. There were relatively high conversion rates in both laparoscopic (0% to 15%) and robotic procedures (4.5% to 10%). There were no significant differences regarding resection margins, rates of pancreatic fistula formation, bile leak, and delayed gastric emptying, reoperation rates, and intraoperative and postoperative mortality. On the contrary, blood loss was less in minimally invasive than open operations, although this difference was not always significant. Moreover, totally laparoscopic and robotic procedures lasted longer than the open ones, whereas hand-assisted laparoscopic procedures did not. However, the findings regarding the number of the retrieved lymph nodes, the length of hospital stay, and costs were inconclusive and controversial. Conclusions: Laparoscopic and robotic pancreaticoduodenectomy are feasible, safe, and oncologically equivalent alternatives to open pancreaticoduodenectomy. Minimally invasive operations have the advantage of the less blood loss, but totally laparoscopic and robotic procedures last longer than open procedures.


World Journal of Gastrointestinal Oncology | 2012

Simultaneous occurrence of colonic adenocarcinoma and MALT lymphoma: A series of three cases

Theodoros Argyropoulos; Periklis G. Foukas; Maria Kefala; Panagiotis Xylardistos; Sotirios Papageorgiou; Nikolaos Machairas; Evmorfia Boltetsou; Anastasios Machairas; Ioannis Panayiotides

Simultaneous development of adenocarcinoma and primary B cell lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma of the colon is rare; only one case has so far been reported out of 13 cases with the coexistence of colonic adenocarcinoma with involvement of the colon by lymphoma. We hereby present three more cases, two females (aged 75 and 71 years) and a male (aged 72 years). All three underwent colectomy based on a preoperative biopsy revealing colonic carcinoma. Histological examination of the resection specimens disclosed a colonic adenocarcinoma in two cases, whereas a tubulovillous adenoma with superficial foci of intraepithelial adenocarcinoma was seen in the third case. Moreover, in all three cases, a coexisting MALT lymphoma was diagnosed in the colon (1 case), in both colon and adjacent lymph nodes (1 case) or in colonic lymph nodes and omentum (1 case). In the last case, a post-operative bone marrow biopsy revealed extensive infiltration of the bone marrow, due to which the patient received postoperative chemotherapy. Diagnostic and treatment issues are briefly discussed.


International Journal of Antimicrobial Agents | 2015

Pre-treatment with probiotics prolongs survival after experimental infection by multidrug-resistant Pseudomonas aeruginosa in rodents: An effect on sepsis-induced immunosuppression

Nikolaos Machairas; Aikaterini Pistiki; Dionyssia-Irini Droggiti; Marianna Georgitsi; Nikolaos Pelekanos; Georgia Damoraki; Grigorios Kouraklis; Evangelos J. Giamarellos-Bourboulis

Based on several randomised clinical studies indicating benefit from oral probiotic intake for the prevention of hospital-acquired infections in critically ill patients, this study aimed to explain the mechanism of action of probiotics for the prevention of lethal experimental infection by multidrug-resistant (MDR) Pseudomonas aeruginosa. Experiments using an Escherichia coli strain susceptible to all antimicrobials were also conducted. C57BL/6 mice were pre-treated intraperitoneally with sterile water for injection or Lactobacillus plantarum. Survival was recorded and mice were sacrificed for measurement of apoptosis and tissue bacterial overgrowth and for isolation and culture of splenocytes for cytokine production. Experiments were repeated after pre-treatment with a commercial preparation of four probiotics (L. plantarum, Lactobacillus acidophilus, Saccharomyces boulardii and Bifidobacterium lactis; LactoLevure(®)). Peripheral blood mononuclear cells (PBMCs) of healthy volunteers were stimulated by heat-killed P. aeruginosa following pre-treatment with medium or probiotics. Pre-treatment with L. plantarum significantly prolonged survival after challenge by either MDR P. aeruginosa (66.7% vs. 31.3%; P=0.026) or E. coli (56.0% vs. 12.0%, P=0.003). Survival benefit was even more pronounced when mice were pre-treated with LactoLevure(®). Tissue bacterial outgrowth and apoptosis of white blood cells and splenocytes were not altered. TNFα and IL-10 production by splenocytes of mice pre-treated with probiotic was increased and IFNγ production was decreased. Pre-treatment with LactoLevure(®) restored production of IL-17. Stimulation of human PBMCs after probiotic pre-treatment was accompanied by reduced gene expression of SOCS3. The results suggest that the protective effect of probiotics is mediated through prevention of sepsis-induced immunosuppression.


Annals of Gastroenterology | 2016

Laparoscopic versus open liver resection for hepatocellular carcinoma: initial experience in Greece

George C. Sotiropoulos; Nikolaos Machairas; Paraskevas Stamopoulos; Ioannis D. Kostakis; Dimitrios Dimitroulis; Dimitrios Mantas; Gregory Kouraklis

Background Liver resection represents the treatment of choice for a small proportion of patients with hepatocellular carcinoma (HCC), amenable to surgery. The remarkable evolution in surgical techniques during the last decades introduced laparoscopic hepatectomy in the operative management of HCC, even in the presence of liver cirrhosis. No comparative study on laparoscopic or open liver resection for HCC has been conducted in Greece yet. Methods Patients undergoing liver resection for HCC by one senior hepatobiliary surgeon in our Institution during the period 11/2011-02/2016 were prospectively sampled and retrospectively analyzed for the purposes of this study. Statistical analysis encompassed Student’s t-test, Fisher’s exact test, the Kaplan-Meier method/log rank test and Cox proportional hazard regression analyses. Results Eleven patients underwent laparoscopic and 21 open liver resection, respectively. Statistical differences between the 2 groups were observed for tumor size (P=0.04), major resections (P=0.01), Pringle maneuver (P=0.008), intraoperative blood transfusion (P=0.03), and duration of operation (P=0.004). Resection margins, and tumor recurrence showed no statistical differences. Three-year postoperative survival after laparoscopic and open hepatectomy was 100%, and 67%, respectively (P=0.06). Regression analysis for patient survival revealed prognostic value for BCLC staging, γ-glutamyl transferase levels, laparoscopic hepatectomy, UICC stage, Dindo-Clavien classification, and hospital stay. Laparoscopic hepatectomy remained as independent predictor of survival by multivariate analysis (P=0.0142). Conclusion Laparoscopic hepatectomy for HCC in chronic liver disease represents a safe and innovative treatment tool in the management of these patients under the presupposition of careful patient selection.


Oncology Letters | 2017

Carcinoid syndrome from a carcinoid tumor of the pancreas without liver metastases: A case report and literature review

Nikolaos Zavras; Demetrios Schizas; Nikolaos Machairas; Vasileia Damaskou; Nikolaos Economopoulos; Anastasios Machairas

A carcinoid tumor of the pancreas (CTP) is a rare pancreatic neoplasm, and usually presents with carcinoid syndrome (CS). CS consists of the classic symptom triad of cutaneous flushing, diarrhea and valvular disease, and occurs in the majority of patients with liver metastases. In the present study, the patient presented with symptoms of CS. A diagnosis of CTP with CS was suspected due to high levels of urine 5-hydroxyindolacetic acid, and this was confirmed by a fine-needle aspiration biopsy. Computed tomography showed extended lymphadenopathy, but no liver metastases. The patient was managed conservatively with octreotide long acting repeatable. To the best of our knowledge, this is the second literature case of CS associated with CTP without liver metastases.


Molecular and Clinical Oncology | 2017

Intraluminal rectal cancer metastasis to the small bowel: An extremely rare case report

Paraskevas Stamopoulos; Nikolaos Machairas; Stylianos Kykalos; Afrodite Nonni; Gregory Kouraklis; Georgios C. Sotiropoulos

Prolonged survival in patients suffering from colorectal cancer (CRC) may lead to the emergence of rare metastatic sites that are not well-documented in the literature. We herein describe a very rare case of an intraluminal small intestinal metastasis in a patient with previously resected CRC. A 71-year-old Caucasian male patient with a history of rectosigmoid junction cancer was initially treated with anterior resection. The tumor was classified as pT3pN0 (0/26) M0, stage II. Eighteen months after the primary surgery, local recurrence was detected in the presacral region, and the patient received combined image-guided radiotherapy and chemotherapy. Two months later, due to residual disease at the level of the anastomosis, the patient underwent additional low anterior resection with a diverting stoma. During extensive adhesiolysis, a small palpable intraluminal mass was identified in the jejunum, and segmental small bowel resection was performed. Pathological examination of the resected specimen confirmed that the lesion was a metastasis from the CRC primary. The precise mechanism and clinical significance of CRC metastasis to the small bowel remain unclear. There is limited clinical experience with this condition, as <20 cases have been reported in the literature to date. The main symptoms leading to evaluation, diagnosis and surgical resection are bowel obstruction and bleeding. The present case highlights the possibility of uncomplicated presence of metastatic CRC in the small bowel. Therefore, dilligent inspection of the peritoneal cavity, including the entire length of the gastrointestinal canal, is of paramount importance, particularly in cases of recurrent CRC.


Endocrine Research | 2017

Trends in white blood cell and platelet indices in a comparison of patients with papillary thyroid carcinoma and multinodular goiter do not permit differentiation between the conditions

Nikolaos Machairas; Ioannis D. Kostakis; Anastasia Prodromidou; Paraskevas Stamopoulos; Themistoklis Feretis; Zoe Garoufalia; Christos Damaskos; Gerasimos Tsourouflis; Gregory Kouraklis

ABSTRACT Aim: Carcinogenesis has been related to systematic inflammatory response. Our aim was to study white blood cell and platelet indices as markers of this inflammatory response in thyroid cancer and to associate them with various clinicopathological parameters. Methods: We included 228 patients who underwent thyroidectomy within a period of 54 months, 89 with papillary thyroid carcinoma and 139 with multinodular hyperplasia. We examined potential links between white blood cell and platelet indices on the one hand and the type thyroid pathology and various clinicopathological parameters on the other. Results: No significant differences were detected between thyroid cancer and multinodular hyperplasia and no significant associations were detected with regard to lymphovascular invasion and tumor size. However, the mean platelet volume was higher in multifocal tumors, while the platelet count, plateletcrit, and platelet-to-lymphocyte ratio were increased in cases with extrathyroidal extension and in T3 tumors. Additionally, T3 tumors had lower platelet distribution width. These associations demonstrated low accuracy in predicting these pathological features, but they were found to provide a satisfying negative predictive value, with the exception of the mean platelet volume. Conclusions: White blood cell and platelet indices cannot assist in distinguishing benign goiter from thyroid cancer. However, they can provide information about tumor multifocality, extrathyroidal extension, and presence of a T3 tumor, and they may be used as a means to exclude these pathological characteristics, especially the last two, in papillary thyroid carcinoma.


Acta Chirurgica Belgica | 2013

Expression of Tissue IGF 1, TGFß and EGFR in the Sequential Steps of Intestinal Adaptation in a Rat Model of Short Bowel Syndrome

Evangelos P. Misiakos; G. Agrogiannis; Paul Patapis; I. Dontas; K. Petropoulos; Nikolaos Machairas; E. Giamarellos-Bourboulis”; Theodoros Liakakos; Anastasios Machairas

Abstract Background : The long-term morphological changes and the expression of tissue growth factors IGF 1, TGFß and EGFR in the gut mucosa, during the process of intestinal adaptation were examined. Methods : Four groups of rats were used: a. Sham rats (n = 10) underwent bowel transection and reanastomosis, b. SBS rats underwent an 80% small bowel resection: group A rats (n = 10) were sacrificed 15 days after surgery, group B (n = 10), 30 days after surgery, and group C (n = 10), 60 days after surgery. Morphological small bowel parameters (villus height, lumen diameter and others) of adaptation were examined sequentially. Tissue samples were studied immunohistochemically for the detection of IGF 1, TGFß, and EGFR. Results : There was a significant increase in all morphological parameters at day 15, in the intestinal samples; a further increase followed at day 30 and day 60 (p < 0.0001). Accordingly, an increase in the expression of IGF 1, TGFß and EGFR was noted at day 15 (p < 0.05), and at day 30 (NS). Conclusion : Intestinal adaptation is an ongoing process lasting more than 2 months after massive small bowel resection. Peptide growth factors are expressed in the intestine continuously during this period, but the first two weeks are the most critical for the mucosal growth.


in Vivo | 2018

Impact of Ultrasonic Scalpels for Liver Parenchymal Transection on Postoperative Bleeding and Bile Leakage

Ioannis D. Kostakis; Nikolaos Machairas; Zoe Garoufalia; Anastasia Prodromidou; Georgios C. Sotiropoulos

Background/Aim: Novel techniques for liver parenchymal transection have emerged and they are available to the hepatobiliary surgeon. The aim of our study was to compare two types of ultrasonic scalpels (Lotus and Harmonic) and examine how they perform either alone or in combination with the SonaStar ultrasonic surgical aspiration system regarding postoperative bleeding and bile leakage. Patients and Methods: Our prospectively maintained database of patients who underwent liver resections in our Department was reviewed. One hundred and two patients with solid liver lesions underwent liver resection by a senior hepatobiliary surgeon in our department during a period of 51 months. They were divided into four groups according to the devices that were used for liver parenchymal transection. Results: Patients were divided into the following groups: group 1: Lotus, 32 patients (31.4%); group 2: Lotus+SonaStar, 27 patients (26.5%); group 3: Harmonic, 27 patients (26.5%); group 4: Harmonic+SonaStar, 16 patients (15.7%). There were 5 cases of postoperative bleeding and 9 cases of postoperative bile leakage. No significant difference was found concerning postoperative bleeding (group 1: 2/32; 6.3%, group 2: 2/27; 7.4%, group 3: 0/27; 0%, group 4: 1/16; 6.3%) (p=0.577). Furthermore, no actual difference was detected in terms of postoperative bile leakage (group 1: 2/32; 6.3%, group 2: 3/27; 11.1%, group 3: 3/27; 11.1%, group 4: 1/16; 6.3%) (p=0.866). Conclusion: Both Lotus and Harmonic ultrasonic scalpels provide adequate and similar results concerning postoperative hemorrhage and cholorrhea.


Surgical Infections | 2018

Microbe Isolation from Blood, Central Venous Catheters, and Fluid Collections after Liver Resections

Ioannis D. Kostakis; Nikolaos Machairas; Anastasia Prodromidou; Zoe Garoufalia; Petros Charalampoudis; Georgios C. Sotiropoulos

BACKGROUND Our goal was to evaluate the microbe species responsible for bacteremia or infections related to central venous catheter (CVC) or fluid collections after liver resection. PATIENTS AND METHODS Data from 112 patients (68 males, 44 females) who underwent liver resection over a period of 63 months were reviewed. Patient and tumor characteristics, intra-operative and post-operative data, and the results from cultures of peripheral blood, CVC tips and drained intra-abdominal or intra-throracic fluid collections were collected. RESULTS There were positive blood cultures in 20 patients (17.9%). Coagulase-negative staphylococci (CoNS) and bacteria of enteric flora were the micro-organisms found most frequently and half of the cases had multiple isolated microbe species. The construction of a bilioenteric anastomosis was an independent risk factor for microbe isolation in peripheral blood (odds ratio [OR]: 11, p = 0.01). Furthermore, there were positive cultures of the CVC tip in 14 patients (12.5%), with CoNS being the micro-organism found most frequently and most cases had only one isolated microbe species. No specific risk factor for catheter-related infections was detected. In addition, there were positive cultures of drained fluid collections in 19 patients (17%), with bacteria of enteric flora being the micro-organisms found most frequently and the majority of cases had multiple isolated microbe species. The construction of a bilioenteric anastomosis (OR: 23.5, p = 0.002) and the laparoscopic approach (OR: 4.7, p = 0.0496) were independent risk factors for microbe isolation in drained fluid collections. Finally, the presence of positive blood cultures was associated with the presence of positive culture of CVC tips (p = 0.018) and drained fluid collections (p = 0.001). CONCLUSIONS Post-operative bacteremia, colonization of CVCs, and contamination of fluid collections occur frequently after liver resections and various microbe species may be involved. Patients who undergo hepatectomy and a synchronous construction of a bilioenteric anastomosis are at increased risk of bacteremia development and contamination of fluid collections.

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Ioannis D. Kostakis

National and Kapodistrian University of Athens

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Georgios C. Sotiropoulos

National and Kapodistrian University of Athens

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Georgios C. Sotiropoulos

National and Kapodistrian University of Athens

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Anastasia Prodromidou

National and Kapodistrian University of Athens

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Gregory Kouraklis

National and Kapodistrian University of Athens

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Eleftherios Spartalis

National and Kapodistrian University of Athens

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Paraskevas Stamopoulos

National and Kapodistrian University of Athens

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Zoe Garoufalia

National and Kapodistrian University of Athens

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Anastasios Machairas

National and Kapodistrian University of Athens

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Stylianos Kykalos

National and Kapodistrian University of Athens

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