English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

55 Ercan, Plasma viscosity in ascending aortic aneurysms / doi: 10.14744/ijmb.2019.88598 terms of tissue perfusion. Alterations in these hemorheological parameters directly affect endothelial function through an alternating shear force profile on the endothelial wall [7]. Furthermore, blood viscosity is known to be a function of shear rate and has an impact on wall shear stress [8], which has been reported to be strongly associated with aneurysm formation, progression, and risk of rupture [9]. PV is an important contributing factor to whole blood viscosity [10]. Since endothelial cells are in a state of constant contact with shear stress and plasma, plasma components have a major role in endothelial changes occurring due to PV [11]. Plasma is the blood component remaining once red and white blood cells, as well as other cellular elements, have been removed. Macromolecular components and water content play a role in the viscosity of plasma, which is a concentrated protein solution. The molecular structure and weight of a protein such as fibrinogen affect PV. Greater molecular weight and aggregating capacity, and less spheroid formation contribute to greater PV [12]. Nitric oxide (NO), released by vascular endothelial cells, is also believed to play a role in aneurysm formation [13]. Asymmetric dimethylarginine (ADMA), a potential marker of endothelial dysfunction, is an endogenous inhibitor of both endothelial and inducible nitric oxide synthase (NOS), and has been associated with mortality in several acute and chronic vascular conditions [14, 15]. The aim of this study was to investigate change in PV and the endothelial markers of fibrinogen, nitrite and NOx, and ADMA before and after AsAA surgery and to compare the results with those of healthy patients. Materials and Methods Subjects and study design The study group included a total of 23 patients who underwent surgical repair for AsAA (mean age: 63±8 years), and the control group consisted of 30 healthy patients without diabetes, hypoor hyperlipidemia, or heart disease (mean age: 72±10 years). The mean ascending aorta diameter was 3.60±0.20 cm in the control group. The mean diameter of the ascending aorta in the study group was 6.00±1.80 cm. The exclusion criteria included the presence of congenital valve disease (bicuspid, unicuspid, or quadricuspid aortic valve, etc.), a hereditary connective tissue disorder (Marfan, Ehlers-Danlos, Loeys-Dietz syndromes, etc.), reoperation, or a dissecting aortic aneurysm. The plasma creatinine and glycated hemoglobin levels were within normal limits in all of the control and study group patients. In the study group, 17 patients had been diagnosed with hypertension and were on metoprolol 50 mg once daily. Eight patients were current tobacco smokers (1 packet/day). All of the operations in the study group were elective procedures. The study protocol was approved by the Republic of Turkey Ministry of Health, Public Hospitals Administration of Turkey, Kartal Koşuyolu High Specialization Training and Research Hospital, Date: 27.03.2013 Number of Approval: 2013.1/21. Oral and written informed consent were obtained from all of the participants. Surgical procedure Surgical treatment was initiated under general anesthesia following general preparations for surgery. A Bentall-De Bono procedure (replacement of the ascending aorta and aortic valve using a mechanical valve prosthesis) was performed in 6 cases, and a David procedure (reimplantation of the aortic valve within a vascular graft) was performed in 3 patients. A tubular graft was interposed in the ascending aorta in the remaining 14 patients. All of the patients were monitored in the intensive care unit during the anesthesia recovery period. Assessments Patient blood samples were obtained preoperatively and at postoperative day 7 for plasma evaluation. In the control group, a single sample was obtained for comparison. The collected blood samples were drawn into vacutainers containing potassium ethylenediaminetetraacetic acid as an anticoagulant. The plasma was separated using centrifugation at 3000 x g for 15 minutes in order to analyze the biochemical parameters. All of the parameters were analyzed at the central laboratory of Kartal Kosuyolu Research and Training Hospital. The Hct, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels were determined with enzymatic methods using commercial kits (Roche/Hitachi Modular Analytics System; Roche Diagnostics Corp., Indianapolis, IN, USA). The intra-assay and inter-assay coefficients of variation were 2.8% and 3.2%, respectively, for TC; 3.9% and 4.7%, respectively, for HDL-C; 4.1% and 4.8%, respectively, for LDL-C; and 2.9% and 3.6%, respectively, for TG. Biochemical parameters were analyzed using a biochemical assay analyzer (Cobas 8000 c 702 module; Roche Diagnostics, Corp., Indianapolis, IN, USA). Once the biochemical assays were completed, the remaining plasma was sent to the Department of Biophysics, Istanbul University-Cerrahpasa. The samples were stored at -80oC for 2 weeks for PV, fibrinogen, NOx, and ADMA analysis. PV was measured using a Coulter Harkness capillary viscometer (Serial Number 6083; Beckman Coulter, Inc., Brea, CA, USA) at 37oC. The intraand inter-assay coefficients of variation for PV were 3.8% and 4.0%, respectively. Plasma fibrinogen levels were measured using the clotting Clauss method with Multifibren U (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany) commercial kits and the data were expressed as g/L [8]. NOx was determined according to the concentration of nitrate plus nitrite in the serum using a colorimetric method with a Griess reagent (Cayman Chemical Corp., Ann Arbor, MI, USA). Spectrophotometric quantification of nitrite using the Griess reagent is a straightforward method, and nicotinamide adenine dinucleotide-dependent enzyme nitrate reductase was used to convert the nitrate to nitrite prior to quantification with the Griess reagent. The intraand inter-assay coefficients of variation for NOx were 4.9% and 5.1%, respectively, and the data were expressed as μmol/L. 56 Int J Med Biochem Plasma ADMA concentrations were determined with a competitive enzyme-linked immunosorbent assay (ADMA ELISA kit; Diagnostika GmbH, Hamburg. Germany). The intraand interassay coefficients of variation were 3.4% and 4.5%, respectively, and the results were expressed as mmol/L. Statistical analysis The results were expressed as mean±SD. The statistical analyses were performed using SPSS Statistics for Windows, Version 17.0 (SPSS, Inc., Chicago, IL, USA). An independent t-test was applied to analyze the significance of the difference between the control and study groups, and a paired sample t-test was applied to analyze the significance of the difference between the study groups. A Wilcoxon signed-rank test was used to analyze intra-group variation. A probability level of 0.05 was used as the criterion of significance in all analyses.

The relationship between plasma viscosity and endotel markers in patients with ascending aortic aneurysms: a pilot study