Panayiotis D Ziakas

Dr. Panayiotis D Ziakas


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2015 in World Journal of Hepatology
Verified
Journal Article
Open access
LPLoukia S Poulou
Loukia S Poulou
Evanthia BotsaEvanthia Botsa
Evanthia Botsa
ITIoanna Thanou
Ioanna Thanou
PZPanayiotis D Ziakas
Panayiotis D Ziakas
LTLoukas Thanos
Loukas Thanos
Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse, steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency (RFA) and microwave ablation (MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent (approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival.

1 March 2015 in American Journal of Gastroenterology
Verified
Journal Article
Closed access
IZIoannis M Zacharioudakis
Ioannis M Zacharioudakis
FZFainareti N Zervou
Fainareti N Zervou
EPElina Eleftheria Pliakos
Elina Eleftheria Pliakos
PZPanayiotis D Ziakas
Panayiotis D Ziakas
EMEleftherios Mylonakis
Eleftherios Mylonakis
It has been suggested that colonization with C. difficile protects from infection. Nevertheless, the association between carriage of toxinogenic strains and ensuing C. difficile infections (CDIs) has not been studied. We searched PubMed and EMBASE databases up to 20 June 2014, using the term "difficile". Our primary outcomes of interest included the prevalence of isolation of toxinogenic C. difficile or its toxins from asymptomatic patients on hospital admission through stool or rectal swab testing and the risk of ensuing infection among colonized and noncolonized patients. Data on previous hospitalization, antibiotic, and proton pump inhibitor (PPI) use and prior CDIs among colonized and noncolonized patients were also extracted. Nineteen out of 26,081 studies on 8,725 patients were included. The pooled prevalence of toxinogenic C. difficile colonization was 8.1% (95% confidence interval (CI) 5.7-11.1%), with an increasing trend over time (P=0.003), and 10.0% (95% CI 7.1-13.4%) among North American studies. Patients colonized upon hospital admission had a 5.9 times higher risk of subsequent CDIs compared with noncolonized patients (relative risk (RR) 5.86; 95% CI 4.21-8.16). The risk of CDI for colonized patients was 21.8% (95% CI 7.9-40.1%), which was significantly higher than that of noncolonized patients (3.4%; 95% CI 1.5-6.0%; P=0.03), with an attributable risk of 18.4%. History of hospitalization during the previous 3 months was associated with a higher risk of colonization (RR 1.63; 95% CI 1.13-2.34), as opposed to previous antibiotic (RR 1.07; 95% CI 0.75-1.53) and PPI use (RR 1.44; 95% CI 0.94-2.23), as well as history of CDI (RR 1.45; 95% CI 0.66-3.18) that had no impact. Over 8% of admitted patients are carriers of toxinogenic C. difficile with an almost 6 times higher risk of infection. These findings update current knowledge regarding the contribution of colonization in CDI epidemiology and stress the importance of preventive measures toward colonized patients.

1 July 2018 in Clinical Microbiology Reviews
Verified
Journal Article
Open access
PDF file
EPElina Eleftheria Pliakos
Elina Eleftheria Pliakos
NANikolaos Andreatos
Nikolaos Andreatos
FSFadi Shehadeh
Fadi Shehadeh
PZPanayiotis D Ziakas
Panayiotis D Ziakas
Eleftherios MylonakisEleftherios Mylonakis
Eleftherios Mylonakis
SUMMARY: Bloodstream infections are associated with considerable morbidity and health care costs. Molecular rapid diagnostic tests (mRDTs) are a promising complement to conventional laboratory methods for the diagnosis of bloodstream infections and may reduce the time to effective therapy among patients with bloodstream infections. The concurrent implementation of antimicrobial stewardship programs (ASPs) may reinforce these benefits. The aim of this study was to evaluate the cost-effectivenesses of competing strategies for the diagnosis of bloodstream infection alone or combined with an ASP. To this effect, we constructed a decision-analytic model comparing 12 strategies for the diagnosis of bloodstream infection. The main arms compared the use of mRDT and conventional laboratory methods with or without an ASP. The baseline strategy used as the standard was the use of conventional laboratory methods without an ASP, and our decision-analytic model assessed the cost-effectivenesses of 5 principal strategies: mRDT (with and without an ASP), mRDT with an ASP, mRDT without an ASP, conventional laboratory methods with an ASP, and conventional laboratory methods without an ASP. Furthermore, based on the availability of data in the literature, we assessed the cost-effectivenesses of 7 mRDT subcategories, as follows: PCR with an ASP, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) analysis with an ASP, peptide nucleic acid fluorescentin situhybridization (PNA-FISH) with an ASP, a blood culture nanotechnology microarray system for Gram-negative bacteria (BC-GP) with an ASP, a blood culture nanotechnology microarray system for Gram-positive bacteria (BC-GN) with an ASP, PCR without an ASP, and PNA-FISH without an ASP. Our patient population consisted of adult inpatients in U.S. hospitals with suspected bloodstream infection. The time horizon of the model was the projected life expectancy of the patients. In a base-case analysis, cost-effectiveness was determined by calculating the numbers of bloodstream infection deaths averted, the numbers of quality-adjusted life years gained, and incremental cost-effectiveness ratios (ICERs). In a probabilistic analysis, uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. In the base-case analysis, MALDI-TOF analysis with an ASP was the most cost-effective strategy, resulting in savings of $29,205 per quality-adjusted life year and preventing 1 death per 14 patients with suspected bloodstream infection tested compared to conventional laboratory methods without an ASP (ICER, −$29,205/quality-adjusted life year). BC-GN with an ASP (ICER, −$23,587/quality-adjusted life year), PCR with an ASP (ICER, −$19,833/quality-adjusted life year), and PCR without an ASP (ICER, −$21,039/quality-adjusted life year) were other cost-effective options. In the probabilistic analysis, mRDT was dominant and cost-effective in 85.1% of simulations. Importantly, mRDT with an ASP had an 80.0% chance of being cost-effective, while mRDT without an ASP had only a 41.1% chance. In conclusion, our findings suggest that mRDTs are cost-effective for the diagnosis of patients with suspected bloodstream infection and can reduce health care expenditures. Notably, the combination of mRDT and an ASP can result in substantial health care savings.

1 January 2012 in Medicine
Verified
Journal Article
Closed access
MVMichael Voulgarelis
Michael Voulgarelis
PZPanayiotis D Ziakas
Panayiotis D Ziakas
APAristea Papageorgiou
Aristea Papageorgiou
EBEvangelia Baimpa
Evangelia Baimpa
ATAthanasios G. Tzioufas
Athanasios G. Tzioufas
HMHaralampos M. Md Moutsopoulos
Haralampos M. Md Moutsopoulos
Sjögren syndrome (SS) has been associated with the development of non-Hodgkin lymphoma (NHL). From a cohort of 584 SS patients followed in our department from 1980 to 2010, we retrospectively analyzed 53 consecutive NHL cases. Considerations included histologic type, clinical manifestation and NHL staging, treatment, response rate and overall survival (OS), event-free survival (EFS), and standardized mortality ratio (SMR). Mucosa-associated lymphoid tissue (MALT) lymphomas constituted the majority (59%) of NHL subtypes, followed by nodal marginal zone lymphomas (NMZLs) (15%) and diffuse large B-cell lymphomas (DLBCLs) (15%). Six lymphoma patients died during the median follow-up of 40.8 months. The corresponding age/sex-adjusted SMR of SS with and without NHLs versus the general population was 3.25 (95% confidence interval [CI] 1.32–6.76) and 1.08 (95% CI, 0.79–1.45), respectively. A “watch and wait” policy was adopted for 9 patients with asymptomatic localized salivary MALT lymphomas. Eight patients with limited-stage MALT lymphomas and extraglandular manifestations were treated with rituximab. Ten MALT lymphoma patients with disseminated disease received chemotherapy with or without rituximab. The 3-year OS and EFS in patients with MALT lymphomas was 97% and 78%, respectively. Rituximab plus CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) was the chosen therapeutic intervention for patients with DLBCLs. A successful outcome was recorded for this group, with 100% OS and EFS at 3 years. Patients with NMZLs had a less favorable outcome, with a 3-year OS of 80% and EFS of 53%. Our results describe the course and prognosis of SS-associated NHL and highlight the need for a risk-stratified treatment approach.

29 November 2007 in Arthritis & Rheumatism
Verified
Journal Article
Open access
PDF file
MMMENELAOS MANOUSSAKIS
MENELAOS MANOUSSAKIS
SBS. Boiu
S. Boiu
PKP. Korkolopoulou
P. Korkolopoulou
EKE. K. Kapsogeorgou
E. K. Kapsogeorgou
NKN. Kavantzas
N. Kavantzas
HMH. M. Moutsopoulos
H. M. Moutsopoulos
Objective: To evaluate the expression profile of infiltrating macrophages and dendritic cells (DCs) as well as of interleukin‐18 (IL‐18) and IL‐12 in the minor salivary gland (MSG) lesions of patients with Sjögren's syndrome (SS), and to assess the relationship of these factors with disease parameters.Methods: Macrophages, DCs, T cells, B cells, proIL‐18, mature IL‐18, and IL‐12 were detected by single‐ and double‐labeling immunohistochemistry in MSG specimens from 21 patients with primary SS (13 of 21 tested for IL‐12), 7 patients with secondary SS, and 9 disease control patients. Expression profiles were assessed for correlations with various disease parameters, including adverse predictors of lymphoma development.Results: MSGs from patients with SS (but not from disease controls) manifested increased infiltration by macrophages and DCs, strong expression of IL‐18 by macrophages (particularly in B cell–rich areas and in germinal center–like structures in primary SS), and expression of IL‐12 by mononuclear cell infiltrates. In primary SS, high infiltration by macrophages correlated with SG enlargement (P = 0.01). The DC infiltration rate correlated positively with the macrophage infiltration rate (P = 0.04), occurrence of SG enlargement (P = 0.03), and presence of C4 hypocomplementemia (P = 0.05), and inversely with serum C4 complement levels (P = 0.001). The rate of infiltration by IL‐18–expressing cells correlated positively with biopsy focus scores (P < 0.001), larger infiltrates of macrophages (P = 0.01), DCs (P = 0.01), and B cells (P = 0.02), and SG enlargement (P = 0.02), and negatively with serum C4 complement levels (P = 0.02). The rate of infiltration by IL‐12–expressing cells correlated inversely with that by IL‐18–expressing cells (P = 0.001), biopsy focus scores (P = 0.003), and SG enlargement (P = 0.01), and positively with serum C4 complement levels (P = 0.05).Conclusion: In patients with primary SS, infiltration of the SG by macrophages and DCs and expression of IL‐18 and IL‐12 appear to play active roles in the expansion and organization of infiltrative injuries and have a correlation with certain predictors of lymphoma development.

1 February 2006 in Annals of the Rheumatic Diseases
Verified
Journal Article
Closed access
PDF file
SGS Giannouli
S Giannouli
MVMichael Voulgarelis
Michael Voulgarelis
PZPanayiotis D Ziakas
Panayiotis D Ziakas
ATA G Tzioufas
A G Tzioufas
Haematological abnormalities are common in systemic lupus erythematosus. Anaemia is found in about 50% of patients, with anaemia of chronic disease being the most common form. Impaired erythropoietin response and presence of antibodies against erythropoietin may contribute to the pathogenesis of this type of anaemia. Patients with autoimmune haemolytic anaemia usually belong to a distinct category, which is associated with anticardiolipin antibodies, thrombosis, thrombocytopenia, and renal disease, often in the context of secondary antiphospholipid syndrome. Autoantibodies, T lymphocytes, and deregulation of the cytokine network can affect bone marrow erythropoiesis, leading to anaemia.