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Öğe Homocysteine thiolactonase activity in coronary atherosclerosis(BAYRAKOL MEDICAL PUBLISHER, 2020) Altinay, Aylin; Kisa, Ucler; Tulmac, Murat; Ozkan, YesimAim: Discovery of paraoxonase natural substrate, homocysteine thiolactone, shed more light on the protective role of paraoxonase and toxicity of homocysteine. Since homocysteine thiolactone and paraoxon were hydrolyzed at different sites in the PON protein, the aim of this study was to investigate the Hcy-thiolactonase (HTase). This study was undertaken to ascertain whether low the Hcy-thiolactonase acitivity is associated with paraoxonase activity and to clarify its relation with ox-LDL and total plasma homocysteine levels in coronary artery diseasase. Material and Methods: Forty-six subjects undergoing coronary angiography for suspected coronary artery disease were included. Depending on angiography results, 14 subjects with normal coronary arteries according to Gensini scoring were selected as a control group. Serum homocysteine thiolactonase and paraoxonase activities were measured spectrophotometrically. Homocysteine, ox-LDL levels were measured with ELISA methods. Results: A significant decrease in HTase activity and a significant increase in ox-LDL levels were observed in patients compared with controls (p=0.040, p=0.037, respectively). Homocysteine levels and paraoxonase activity did not show any statistically significant difference between groups. Positive correlations between HTase and paraoxonase activities were observed in study groups (rs=0.742, p=0.004 for control, rs=0.494, p=0.01 for patient). Discussion: HTase activity decreased in coronary artery disease in spite of unchanged paraoxonase activity and is associated with a higher level of ox-LDL. N-homocysteinylation of HDL changes the properties of apolipoprotein, which could affect the enzymatic activities. When considering a relationship between HTase activity and HDL levels, correlation observed in our study confirms a possible consequence of low PONs homocysteine thiolactonase activity.Öğe The multidisciplinary approach to biochemistry laboratory education(Turkish Biochem Soc, 2013) Erkoc, Figen; Sepici-Dincel, Aylin; Kayrin, Levet; Ozkan, Yesim; Eksioglu, Subhan; Yuksel, Meral; Simsek, BolkanEuropean Union's Life Long Learning Programmes and the Bologna Process describe new classifications. Related with these new classifications, our higher education system is being restructured under the name of National Qualification Frameworks. Between the National and European programmes comparability and the transparency is expected to promote life-long learning. The workshop named as "Biochemistry Laboratory Training Workshop on Multi-Disciplinary Approach" was held on 3-4 May 2012 in Ankara with the scope of biochemistry laboratory culture, education, laboratory work and experimental methodology consisted of gain and the development of scientific thinking skills. As a result of the workshop, it was mentioned that, biochemistry theoretical course and biochemistry laboratory are being taught in different faculties, colleges and vocational schools. Biochemistry's interdisciplinary character, its' being closely related to physiology, being based on chemistry/physics principles and conceptions and extending increasingly to molecular biology, molecular genetics and nanoscience have brought new approaches in Biochemistry and Biochemistry Laboratory Education. The need for developing new applications using alternative materials leads to modern experimentation to be employed in teaching biochemistry laboratory at different educational establishments. Taking into account the previous studies, the core laboratory training, achievements and targets identified. The timetable of the teaching-learning and the evaluation process were discussed. Besides the core laboratory programme, the awareness of scientific research projects was discussed. It was also noted the coordination between the different programmes and the basic mandatory structure of the laboratories during the time of adaptation to the European. In addition, difficulties in provision of equipment and supplies, the responsibility of governments, readiness and competencies of students, teaching staff qualifications were discussed for the effective laboratory training. Young scientists and graduate students had actively participated in the workshop. Finally positive steps have been taken to develop the ability to work with the cultures of scientific thinking.Öğe Relation of Kynurenine/Tryptophan with Immune and Inflammatory Markers in Coronary Artery Disease(Clin Lab Publ, 2014) Ozkan, Yesim; Sukuroglu, Murat Kadir; Tulmac, Murat; Kisa, Ucler; Simsek, BolkanBackground: Inflammation and immune activation have a crucial role in the pathogenesis of cardiovascular diseases. Indolamine 2,3-dioxygenase, a tryptophan catabolising enzyme, is up-regulated with various inflammatory stimuli. The aim of this study was to evaluate the relationship of tryptophan degradation with immune and inflammatory markers in coronary artery disease. Methods: 57 subjects undergoing coronary angiography were recruited. 18 subjects with normal coronary arteries according to Gensini scoring were selected as a control group and the rest of subjects were included in patient group. Serum tryptophan and kynurenine levels were determined with HPLC-UV method, and kynurenine/tryptophan ratio was evaluated as IDO activity. Serum neopterin and myeloperoxidase activity were measured by ELISA method. Results: While the kynurenine/tryptophan ratio and neopterin levels were similar in both groups, the patient group had higher myeloperoxidase and hs-CRP levels than controls (p = 0.02, p = 0.002, respectively). The kynurenine/tryptophan ratio was correlated with neopterin in both groups (r = 0.389, p = 0.025; r = 0.683, p = 0.002, respectively) and with hs-CRP in patients (r = 0.637, p = 0.001). Also, neopterin levels were correlated with hs-CRP in patients (r = 0.755, p = 0.0001). Conclusions: Our results are in line with a role of inflammation in coronary artery disease. The study provides evidence that IDO activity is related with immune and inflammatory states. Also, the study was performed in a limited hospital-based population. Further studies are warranted in the larger groups.Öğe Serum homocysteine levels and sildenafil 50 mg response in young-adult male patients without vascular risk factors(Natl Inst Science Communication-Niscair, 2013) Basar, M. Murad; Ozkan, Yesim; Kisa, Ucler; Simsek, BolkanThe aim of the present study was to investigate serum homocysteine levels in patients with erectile dysfunction and to evaluate the relationship between serum homocysteine levels and response to the standard 50 mg phosphodiesterase 5 inhibitor treatment. Twenty-eight erectile dysfunction patients having normal vascular parameter according to Penile Doppler Ultrasonography and twenty healthy subjects were enrolled in the study. All subjects filled The International Index of Erectile Function (IIEF) questionnaire. A total of 4-6 doses of phosphodiesterase 5 inhibitor (sildenafil 50 mg) were given to patients. Later, they were divided into two groups as sildenafil responder and non-responder. Serum homocysteine levels were compared in groups based on sildenafil response: Compared with healthy subject, higher homocysteine levels were observed in patients with erectile dysfunction (p = 0.005), especially in sildenafil non-responder group (p = 0.005). There was significant negative correlation between homocysteine and TIFF scores in group responder to sildenafil treatment (r = -0.698, p = 0.008). Mean IIEF scores of patients with non-responder to sildenafil 50 mg were lower than those of controls (p = 0.0001), but mean IIEF scores of patients with responders approached values observed in control subjects (p = 0.002). The results indicated that measurement of serum homocysteine levels could be used as a marker for the evaluation of efficacy of phosphodiesterase 5 inhibitor and the selection of efficacious alternative therapies.
