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Dive into the research topics where Nil Guler is active.

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Featured researches published by Nil Guler.


Journal of Infection | 2016

A fatal case of healthcare associated Crimean-Congo haemorrhagic fever with severe disease and multi-organ failure

Mustafa Sunbul; Saban Esen; Tom E. Fletcher; Ahmet Dilek; Nil Guler; Nicholas J. Beeching; Hakan Leblebicioglu

Department of Infectious Diseases and Clinical Microbiology, Ondokuz Mayis University Medical School, Samsun, Turkey Liverpool School of Tropical Medicine, Liverpool, United Kingdom, Department of Intensive Care, Ondokuz Mayis University Medical School, Samsun, Turkey Department of Haematology, Ondokuz Mayis University Medical School, Samsun, Turkey NIHR Helalth Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool L69 7BE, United Kingdom


Clinical and Applied Thrombosis-Hemostasis | 2017

Dysregulation of Tissue Factor, Thrombin-Activatable Fibrinolysis Inhibitor, and Fibrinogen in Patients Undergoing Total Joint Arthroplasty

Christopher Wanderling; Jeffrey Liles; Elissa Finkler; Peter Carlsgaard; William Hopkinson; Nil Guler; Debra Hoppensteadt; Jawed Fareed

Total joint arthroplasty (TJA) of the hip or knee (THA, TKA) has become an increasingly common procedure. While TJA is a successful treatment for individuals experiencing degenerative joint diseases, it is well known that one of the most common perioperative complications of TJA is deep venous thrombosis (DVT). To profile tissue factor (TF), microparticle-tissue factor (MP-TF), thrombin-activatable fibrinolysis inhibitor (TAFI), and fibrinogen levels in patients undergoing TJA to determine potential preexisting Hemostatic dysregulation. De-identified blood samples were obtained from patients undergoing TJA 1 day pre- and 1 day postprocedure. Plasma samples were analyzed using enzyme-linked immunosorbent assay kits for fibrinogen, TAFI, TF, and MP-TF; fibrinogen levels were also assessed using a clot-based activity assay. In comparison with healthy controls, there were significant increases of fibrinogen and MP-TF levels, while there were significant decreases in TF and TAFI levels in the preoperative and postoperative patients. Comparing the pre versus postoperative patients, no significant differences were found; interestingly, however, surgical intervention exacerbated the changes found in the preoperative samples compared to the controls. The results of this study confirm that patients undergoing TJA have preexisting alterations in the fibrinolytic system. Surgical intervention tended to exacerbate these changes. The alterations observed in this study may provide insight as to why TJA is associated with higher rates of DVT and thromboembolism.


Clinical and Applied Thrombosis-Hemostasis | 2016

Fibrinolytic Dysregulation in Total Joint Arthroplasty Patients: Potential Clinical Implications.

Nil Guler; Andrew Burleson; Daneyal Syed; Andrew Banos; William Hopkinson; Debra Hoppensteadt; Harold W. Rees; Jawed Fareed

Background: The alterations of the fibrinolytic components in osteoarthritic joint disease and their postsurgical modulation are not clearly understood. Preexisting hemostatic dysfunction may lead to both thrombotic and bleeding events in these patients. Aim: To profile fibrinolytic parameters in patients undergoing total joint arthroplasty prior to and on postoperative day 1. Methods: A total of 98 total joint arthroplasty patients were included in this study. Blood samples were drawn preoperatively and on postoperative day 1 status posttotal knee or total hip arthroplasty surgery. d-Dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using commercially available enzyme-linked immunosorbent assay kits. Antiplasmin activity was measured by using a functional method. Results: Preoperative PAI-1, d-dimer, and tPA levels were significantly higher in arthroplasty patients compared to healthy controls. Preoperative antiplasmin level was lower than controls. Postoperative levels of PAI-1 and d-dimer were increased compared to preoperative values. Postoperative antiplasmin values were lower than preoperative levels. Changes in tPA was not significant. There was no correlation between preoperative PAI-1 and d-dimer levels. Pre- and postoperative percentage changes in each individual were calculated for PAI-1, d-dimer, tPA, and antiplasmin. There was a positive correlation between d-dimer and PAI-1. Negative correlations between antiplasmin and d-dimer and between antiplasmin and PAI-1 were noted. Conclusion: These results confirm the perturbation in the fibrinolytic system of patients undergoing total joint arthroplasty surgery. Surgical intervention may also enhance the observed changes. The alterations in the fibrinolytic system may lead to the observed hemostatic complications such as bleeding, hematoma formation, or potential need for blood transfusion.


International Journal of Infectious Diseases | 2015

A case of severe babesiosis treated successfully with exchange transfusion

Esra Tanyel; Nil Guler; Murat Hokelek; Fatma Ulger; Mustafa Sunbul

Babesiosis is a zoonotic disease that may be asymptomatic or result in severe clinical conditions, with severe hemolysis, hepatic, and renal failure, in humans. Clinical symptoms depend on the species and immune status of the host. The disease is especially severe in those of advanced age, those with an immune deficiency, and the splenectomized. A severe case of babesiosis that developed in a splenectomy patient is presented here; the patient was admitted from a rural region with severe anemia and a deterioration in her general condition, with an initial diagnosis of malaria. In such situations, an exchange transfusion (ET), in addition to antimicrobial treatment, could be lifesaving.


Clinical and Applied Thrombosis-Hemostasis | 2018

Biomarkers of Endothelial, Renal, and Platelet Dysfunction in Stage 5 Chronic Kidney Disease Hemodialysis Patients With Heart Failure

Ryan McMillan; Leonidas Skiadopoulos; Debra Hoppensteadt; Nil Guler; Vinod Bansal; Ravipresenna Parasuraman; Jawed Fareed

The aim of this study was to determine the role of endothelial, renal, and inflammatory biomarkers in the pathogenesis of heart failure (HF) in patients with stage 5 chronic kidney disease (CKD5) undergoing maintenance hemodialysis (HD). Plasma levels of biomarkers—kidney injury molecule 1 (KIM-1), N-terminal pro brain natriuretic peptide (NT-proBNP), glycated hemoglobin, neutrophil gelatinase–associated lipocalin, interleukin-18,platelet-derived growth factor, platelet factor 4 (PF4), 25-OH vitamin D, parathyroid hormone (PTH), endothelin, and endocan—were measured in CKD5-HD patients at the Loyola University Ambulatory Dialysis facility. The HF (+) CKD5-HD patients, as compared to HF (−) CKD5-HD patients, exhibited significantly elevated NT-proBNP (P = .0194) and KIM-1 (P = .0485). The NT-proBNP in HF (+) CKD5-HD patients was found to correlate with the levels of serum potassium (P = .023, R = −.39), calcium (P = .029, R = −.38), and PF4 (P = .045, R = −.35). The KIM-1 in HF (+) CKD5-HD patients was found to correlate with PTH (P = .043, R = −.36) and 25-OH vitamin D (P = .037, R = .36). Elevated plasma NT-proBNP and KIM-1 in CKD5-HD and HF (+) CKD5-HD patients suggest that natriuretic peptides and KIM-1 may contribute to the pathogenesis of HF in CKD5-HD patients.


PLOS ONE | 2016

Apoptosis-Related Gene Expression in an Adult Cohort with Crimean-Congo Hemorrhagic Fever

Nil Guler; Cafer Eroglu; Hava Yilmaz; Adil Karadag; Hasan Alacam; Mustafa Sunbul; Tom E. Fletcher; Hakan Leblebicioglu

Crimean-Congo Hemorrhagic Fever (CCHF) is a life threatening acute viral infection characterized by fever, bleeding, leukopenia and thrombocytopenia. It is a major emerging infectious diseases threat, but its pathogenesis remains poorly understood and few data exist for the role of apoptosis in acute infection. We aimed to assess apoptotic gene expression in leukocytes in a cross-sectional cohort study of adults with CCHF. Twenty participants with CCHF and 10 healthy controls were recruited at a tertiary CCHF unit in Turkey; at admission baseline blood tests were collected and total RNA was isolated. The RealTime ready Human Apoptosis Panel was used for real-time PCR, detecting differences in gene expression. Participants had CCHF severity grading scores (SGS) with low risk score (10 out of 20) and intermediate or high risk scores (10 out of 20) for mortality. Five of 20 participants had a fatal outcome. Gene expression analysis showed modulation of pro-apoptotic and anti-apoptotic genes that facilitate apoptosis in the CCHF patient group. Dominant extrinsic pathway activation, mostly related with TNF family members was observed. Severe and fatal cases suggest additional intrinsic pathway activation. The clinical significance of relative gene expression is not clear, and larger longitudinal studies with simultaneous measurement of host and viral factors are recommended.


Clinical and Applied Thrombosis-Hemostasis | 2016

Perioperative Factors and Their Effect on the Fibrinolytic System in Arthroplasty Patients.

Andrew Burleson; Nil Guler; Andrew Banos; Daneyal Syed; Christopher Wanderling; Debra Hoppensteadt; Harold W. Rees; Jawed Fareed; William Hopkinson

Background: Total joint arthroplasty (TJA) patients are mostly of advanced age and with comorbidities such as increased body mass index (BMI) and impaired glucose tolerance. These factors and type of surgery may affect the fibrinolytic system. Aim: To investigate the effect of age, sex, BMI, type of surgery, and tranexamic acid (TXA) treatment on the fibrinolytic system in TJA patients. Methods: Ninety-nine patients undergoing TJA (32 total hip arthroplasty [THA] and 67 total knee arthroplasty [TKA]) were included in this study. Blood samples were drawn at preoperative clinic appointments and on postoperative day 1. Antigenic levels of d-dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using a commercially available enzyme-linked immunosorbent assay kit. Antiplasmin activity was measured using functional method. Age, gender, hemoglobin (Hb) levels, and BMI were collected from the records. Results: Preoperative d-dimer and tPA levels were positively correlated with age, whereas preoperative antiplasmin was negatively correlated with age. Body mass index was only associated with preoperative tPA levels. There was no significant difference in postoperative levels of d-dimer, PAI-1, tPA, or antiplasmin between patients treated with TXA or without TXA. Percentage change in d-dimer and tPA showed significantly lower values in patients treated with TXA compared to the nontreated group. Type of surgery did not affect the fibrinolytic markers. Conclusion: These results confirm that advanced age and elevated BMI positively contribute to fibrinolytic dysregulation in TJA patients, whereas TXA seems to decrease the fibrinolytic activity.


Clinical and Applied Thrombosis-Hemostasis | 2018

Levels of Matrix-Degrading Enzymes and Lubricin in Patients With Degenerative Joint Disease Requiring Arthroplasty:

Christopher Wanderling; Jeffrey Liles; Elissa Davis; Daniel Schmitt; Stephen Statz; Nil Guler; Debra Hoppensteadt; Jawed Fareed; William Hopkinson

Total joint arthroplasty (TJA) of the hip or knee (THA and TKA) is the primary surgical intervention for individuals with degenerative joint disease (DJD). Although it is commonly thought that shear force on the joint causes the degradation of articular cartilage, it is possible that there are other factors that contribute to the progression of DJD. It is plausible that specific enzymes that degrade the joint are upregulated, or conversely, there is downregulation of enzymes critical for joint lubrication. The aim of this study is to profile collagenase-1, elastase, heparanase, and lubricin levels in patients undergoing TJA in order to determine potential preexisting dysregulation that contributes to the pathogenesis of DJD. Deidentified blood samples were obtained from patients undergoing TJA 1 day pre- and 1 day postoperatively. Plasma samples were analyzed using enzyme-linked immunosorbent assay kits for elastase, collagenase-1, heparanase, and lubricin. In comparison to healthy controls, there were significant increases in circulating collagenase-1, elastase, and lubricin levels in both the preoperative and postoperative samples. There were no significant differences in heparanase levels in the preoperative or postoperative samples. Comparing the preoperative versus postoperative patient samples, only lubricin demonstrated a significant change. The results of this study confirm that patients undergoing TJA have preexisting alterations in the levels of matrix-degrading enzymes and lubricin. The alterations observed in this study may provide insight into the pathogenesis of DJD.


Clinical and Applied Thrombosis-Hemostasis | 2018

Postoperative Changes in the Systemic Inflammatory Milieu in Older Surgical Patients

Lauren Shih; Nil Guler; Daneyal Syed; William Hopkinson; Kyra N. McComas; Amanda Walborn; Debra Hoppensteadt; Jawed Fareed; Matthew T. Rondina

Dysregulated inflammation is a central component of wound healing following surgery. We prospectively enrolled older patients (n = 25, age 65 ± 7 years) undergoing elective total knee arthroplasty or total hip arthroplasty secondary to advanced osteoarthritis (OA) and healthy controls (n = 48). Inflammatory, proangiogenic (vascular endothelial growth factor [VEGF], monocyte chemoattractant protein-1 [MCP-1], and interleukin-8 [IL-8]), and antiangiogenic (interferon γ [IFN-γ] and IL-4) factors were measured using a high-sensitivity biochip. Patients with OA had significantly higher baseline VEGF (10.5 ± 1.2 pg/mL vs 4.8 ± 0.2 pg/mL, P < .001), MCP-1 (130.6 ± 7.7 pg/mL vs 88.6 ± 3.9 pg/mL, P < .0001), and IL-8 (4.0 ± 0.5 pg/mL vs 2.6 ± 0.1 pg/mL, P < .05). Postoperatively, the levels of VEGF (10.5 ± 1.2 pg/mL vs 18.8 ± 1.5 pg/mL, P < .001) and MCP-1 (130.6 ± 7.7 pg/mL vs 153.1 ± 11.5 pg/mL, P < .05) increased significantly. Baseline and postoperative MCP-1 levels correlated positively and significantly with age. The levels of IFN-γ and IL-4 (which has anti-inflammatory properties) did not significantly differ at baseline in patients with OA compared to controls and did not significantly rise postoperatively. We conclude that systemic levels of pro-inflammatory and angiogenic proteins are increased in patients with OA and rise further postoperatively, while proteins that restrain inflammation and angiogenesis do not coordinately rise. These findings implicate imbalance in inflammatory pathways in OA that may contribute to its pathobiology.


Clinical and Applied Thrombosis-Hemostasis | 2017

Recombinant Factor VIIa–Mediated Activation of Prothrombin Complex Concentrates Studies on the Comparison of NovoSeven With a Biosimilar Product

Nasiredin Sadeghi; Massimo Iacobelli; Behroz Vaziri; Daniel Kahn; Debra Hoppensteadt; Nil Guler; Jawed Fareed

Recombinant factor VIIa (rFVIIa) is used in the management of bleeding in patients with hemophilia. A generic biosimilar version of NovoSeven is also developed (AryoSeven). To compare the activation profile of NovoSeven and AryoSeven, 2 commercially available protein complex concentrates (PCCs) were used. Profilnine activated by RecombiPlasTin 2G resulted in conversions of prothrombin to prethrombin and thrombin at 5 to 30 minutes. However, addition of rFVIIa at final concentration range of 0.25 to 0.5 µg/mL to the same mixture resulted in total conversion of prothrombin to thrombin with a doublet at 36 kDa. Recombinant factor VIIa alone did not generate thrombin in native Beriplex, and the addition of rFVIIa to Beriplex failed to generate thrombin. Beriplex activated by RecombiPlasTin 2G resulted in complete conversion of prothrombin to thrombin. Both NovoSeven and AryoSeven exhibited similar activation profiles. These studies indicate that the activation of PCCs by both rFVIIa preparations results in comparable generation of thrombin.

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Debra Hoppensteadt

Loyola University Medical Center

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Jawed Fareed

Loyola University Medical Center

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Daneyal Syed

Loyola University Medical Center

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William Hopkinson

Loyola University Medical Center

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Mehmet Turgut

Ondokuz Mayıs University

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Christopher Wanderling

Loyola University Medical Center

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Omer Iqbal

Loyola University Medical Center

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Engin Kelkitli

Ondokuz Mayıs University

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Mustafa Sunbul

Ondokuz Mayıs University

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