Person: YARAT, AYŞEN
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YARAT
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AYŞEN
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Publication Metadata only Collagen deposition in myocardium after inhibition of fibrinolytic activity(LIPPINCOTT WILLIAMS & WILKINS, 2005) YARAT, AYŞEN; Hosgor, I; Yarat, A; Yilmazer, S; Girisken, G; Ahmad, SProper function of the heart directly depends on the protection of the myocardial architecture. The fibrinolytic system plays an important role(s) in the protection of myocardial architecture and aiding the pumping function of the heart. We investigated the effect of fibrinolytic system inhibition by tranexamic acid (TXA) on cat myocardium and collagen, which are important constituents of the extracellular matrix. Twenty-eight cats (seven per group) were used. Isotonic saline was administered to the control group (C) and TXA (200 mg/kg) diluted isotonic saline given to experimental groups 1 and 2 (El and E2). Experimental group 3 (E3) animals received 100 mg/kg TXA intravenously daily for 7 days. Bloods were drawn from groups C, El, and E2, and fibrinolytic activity was determined by the euglobulin lysis time, fibrinogen degradation products and fibrin plate lytic area diameters. The group C and group El cats were sacrificed following the infusion. The group E2 and group E3 animals were sacrificed at 24 h and day 7, respectively. Light and electron microscopy, along with the collagen contents of the myocardium, were used to examine the myocardial tissues. Electron microscopic examination in groups El and E2 showed inter-myofibrillar edema, glycogen loss, mitochondrial swelling and disorganization of Z-bands, and a decrease of pinocytotic vesicles in capillary endothelial cells. In group E3, increases of Collagen fibrils in intercellular areas and perivascular areas were noted. Biochemical analyses revealed a highly significant collagen accumulation in the myocardium in group E3 (P < 0.01) as compared with group C. These findings suggest that accumulation of the extracellular matrix containing collagen in the myocardium by fibrinolytic system inhibition may be responsible for the abnormal myocardial architecture, leading to cardiomyopathy and altered cardiac function. (C) 2005 Lippincott Williams Wilkins.Publication Metadata only Kronik periodontitisli ve sağlıklı kişilerin tükürük örneklerinin bazı biyokimyasal parametreler ve sitolojik incelemeler açısından karşılaştırılmasında saklama süresinin belirlenmesi(2009-06-20) ALTURFAN, EBRU IŞIK; YARAT, AYŞEN; AK, ESİN; ALTURFAN E. I., YARAT A., AK E., PİŞİRİCİLER R., KURU B., NOYAN Ü.Publication Metadata only Peanut (Arachis hypogaea) consumption improves glutathione and HDL-cholesterol levels in experimental diabetes(WILEY, 2008) YARAT, AYŞEN; Emekli-Alturfan, Ebru; Kasikci, Emel; Yarat, AysenThe aim of this investigation was to assess the influence of peanut (Arachis hypogaea) consumption on oxidant-antioxidant status and lipid profile in Streptozotocin (STZ) induced diabetic rats. 32 rats were divided into 4 groups as control, control+peanut, diabetic, diabetic+peanut. Control and diabetic groups were fed on standard rat chow whereas control+peanut and diabetic+peanut were fed on standard rat chow supplemented with 0.63 g % peanut for 12 weeks. Serum glucose levels, lipids, Glutathione (GSH), lipid peroxidation (LPO) and atherogenic index (AI) levels were determined at the end of the experiment. In the diabetic group TG (Triglyceride), TC (Total cholesterol), LDL-C (LDL-cholesterol) levels and atherogenic indexes increased significantly whereas HDL-C (HDL-cholesterol) level decreased significantly compared to the control group. The supplementation with peanut in the diabetic group led to significantly higher HDL-C levels and lower AI levels compared to diabetic group. Peanut consumption increased GSH levels significantly both in control and diabetic groups. In conclusion, this study shows that peanut consumption may improve oxidant-antioxidant status in healthy and diabetic status without increasing blood lipids. Moreover, increased HDL-C levels and decreased AI levels in diabetic rats indicate that, peanut consumption may have protective effects against cardiovascular complications of diabetes. Copyright (C) 2007 John Wiley & Sons, Ltd.Publication Open Access Effect of Sample Storage on Stability of Salivary Glutathione, Lipid Peroxidation Levels, and Tissue Factor Activity(WILEY, 2009) YARAT, AYŞEN; Emekli-Alturfan, Ebru; Kasikci, Emel; Alturfan, A. Ata; Pisiriciler, Rabia; Yarat, AysenSaliva samples are often required to be stored for longer periods of time either because of the project protocol or because of lack of funding for analysis. The effects of 6 months storage (fresh, 30, 60, 90 120, 150, and 180d) on the stability of salivary reduced glutathione (GSH), lipid peroxidation (LPO) and 90days of storage (fresh, 15, 30, 60, and 90d) on the stability of salivary tissue factor (TF) activity and the stability of saliva imprint samples at 20 C were evaluated in this study. Salivary GSH, malondialdehyde (MDA) levels as an index of LPO, and TF activities were determined using the methods of Beutler, Yagi, and Quick, respectively. Saliva imprint samples were stained with Giemsa and microscopically examined. Salivary GSH levels and TF MDA levels increased significantly after 6 months of storage at -20 C. Leucocyte, epithelium and bacterium cell counts did not significantly change at the end of 90 d of storage. Saliva samples may be stored up to 1 month at -20 C for LPO assay. For cytological examinations, saliva samples may be stored for 90 d at -20 C. Further studies are needed to determine the stability of salivary GSH, and salivary TF activity stored less than 30 days at -20 C. On the other hand, if saliva samples are required to be stored, to avoid the changes because of different storage periods, we recommend that they must be stored under the same circumstances and in the same time period. J. Clin. Lab. Anal. 23:93-98, 2009. (C) 2009 Wiley-Liss, Inc.Publication Open Access Protective effects ofGinkgo biloba extract against mercury(II)-induced cardiovascular oxidative damage in rats(2007-01) YARAT, AYŞEN; Tunali-Akbay, Tugba; Sener, Goksel; Salvarli, Hanife; Sehirli, Ozer; Yarat, AysenPublication Metadata only Tissue factor activities of streptozotocin induced diabetic rat tissues and the effect of peanut consumption(WILEY, 2007) YARAT, AYŞEN; Emekli-Alturfan, Ebru; Kasikci, Emel; Yarat, AysenBackground Tissue factor (TF) is considered to be a major regulator of normal haemostasis and thrombosis. Circulating TF activity is suggested to be associated with diabetes mellitus. Various tissues and body fluids have TF activity. The aim of the present study was to investigate the TF activity of streptozotocin (STZ) induced diabetic rat tissues. Peanut consumption is reported to be associated with decreased risk of type 2 diabetes. Therefore, the effect of peanut consumption on the TF activity of STZ induced diabetic rat tissues, and haemostatic parameters such as protrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen levels were determined. Methods Twenty-four Wistar rats were divided into 3 groups of 8 rats each as control, STZ-induced diabetic and diabetic + peanut group. Twelve weeks later, TF activity of liver, kidney, spleen, heart, kidney, lung, pancreas and aorta and haemostatic parameters were determined. Results In the diabetic group, TF activities of liver, kidney and spleen increased (p < 0.01) whereas the TF activity of brain decreased (p < 0.01) compared to the control group. Peanut consumption in the diabetic group decreased the TF activity of spleen and aorta (p < 0.01; p < 0.05). Haemostatic parameters did not change significantly in the groups. Conclusion Elevated TF activity in diabetic rat tissues, may contribute to the increased risk of atherothrombotic disease that accompanies the diabetic complications whereas the decreased brain TF activity may be due to a different haemostatic mechanism to protect this vital organ from the diabetic status. The decreased TF activity of peanut given diabetic rat tissues might protect these tissues from the risk of thrombosis. Copyright (c) 2007 John Wiley & Sons, Ltd.Publication Metadata only Melatonin reduces oxidative damage to skin and normalizes blood coagulation in a rat model of thermal injury(PERGAMON-ELSEVIER SCIENCE LTD, 2005) YARAT, AYŞEN; Tunali, T; Sener, G; Yarat, A; Emekli, NThis study was designed to determine the effect of melatonin treatment on the glutathione (GSH) and lipid peroxidation (LPO) levels in the skin as well as prothrombin time (PT) and fibrin degradation products (FDPs) in the blood of rats with thermal injury. Under ether anaesthesia, the shaved dorsum of the rats was exposed to 90degreesC bath for 10 s to induce burn injury. Rats were decapitated either 3 or 24 hours after burn injury. Melatonin (10 mg/ kg) was administered i.p. immediately after burn injury to same animals. In the 24 hour burn group, melatonin injections were repeated for two more occasions 8 and 16 h after burn injury. In the control group the same protocol was applied except that the dorsum was exposed to a 25degreesC water bath for 10 s. Severe skin scald injury (30% of total body surface area) caused a significant decrease in PT at post burn 3 and 24 hours. FDPs was not increased at post burn 3 hour but was significantly increased at post burn 24 hour. GSH levels were significantly depressed at post burn 3 hour but were not changed at post burn 24 hour. LPO levels were significantly increased both at post burn 3 and 24 hours. Skin protein levels were significantly reduced at post burn 24 hour as evidenced by electrophoresis. Treatment of rats with melatonin normalized PT levels both at post burn 3 and 24 hours. FDP decreased at post burn 24 hour due to melatonin treatment. GSH levels significantly increased as a result of melatonin treatment both at post burn 3 and 24 hours melatonin treatment. LPO levels were not changed by melatonin at post burn 3 hour; however, the melatonin significantly decreased LPO values at post burn 24 hours. In conclusion, exogenously administered melatonin reduced skin oxidant damage and normalized the activated blood coagulation induced by thermal trauma. (C) 2004 Elsevier Inc. All rights reserved.Publication Metadata only 6,7-dihydroxy-3-phenylcoumarin inhibits thromboplastin induced disseminated intravascular coagulation(WILEY, 2004) YARAT, AYŞEN; Tunali, T; Yarat, A; Bulut, M; Emekli, N6,7-Dihydroxy-3-phenylcoumarin (DHPC) was tested to determine whether it had any effect on vitamin K inhibition, by investigating the prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen level and platelet count. The anticoagulant and antithrombotic effects of DHPC were compared with those of warfarin by conducting a 4 h acute trial on thromboplastin-induced disseminated intravascular coagulation (DIC), investigating various haemostatic and antioxidant system parameters and performing a haemogram. Of most significance was that in the 5-d DHPC trial on healthy controls, PT, APTT, fibrinogen, platelet count remained within normal levels. In the 4-h DIC trial, both DHPC (0.025 mg/kg, i.v.) and warfarin (0.25 mg/kg, i.v.) significantly inhibited DIC, by reducing the PT, APTT, and fibrin degradation products and increasing fibrinogen levels and platelet count. In the DIC drug groups, lipid peroxidation significantly increased only in the warfarin group and glutathione significantly increased only in the DHPC group. However leucocyte count was significantly higher in the DHPC than the warfarin group. Further investigation is required for why DHPC is effective on the parameters investigated, at doses one-tenth of those of warfarin.Publication Metadata only Antioxidative and lipid lowering effects of 7,8-dihydroxy-3-(4- methylphenyl) coumarin in hyperlipidemic rats(Editio Cantor Verlag GmbH, 2009) YARAT, AYŞEN; Yuce B., Danis O., Ogan A., Sener G., Bulut M., Yarat A.In this study, 7,8-dihydroxy-3-(4-methylphenyl) coumarin (DHMPC), a new coumarin derivative, was tested for the first time to determine whether it had any antioxidant and lipid lowering effects. Hypercholesterolemia was induced by feeding rats with a high cholesterol diet for 17 days. The lipid lowering and antioxidant effects of DHMPC were compared with those of hesperidin (CAS 520-26-3) and rutin (CAS 153-18-4), which have been pharmacologically determined as potential lipid lowering and antioxidant agents. DHMPC significantly decreased serum total cholesterol levels but not as efficient as hesperidin. When the ratios of high density lipoprotein-cholesterol (HDL-cholesterol) to total cholesterol were evaluated, the most significant changes were observed in DHMPC and rutin treatments. The results of serum triglyceride levels indicate that DHMPC and hesperidin did not significantly decrease triglyceride level when compared to rutin group but prevented it to rise. Serum malondialdehyde (MDA) levels increased as expected in high cholesterol diet groups but no significant decrease was observed for serum MDA levels in all treated groups. In contrast to serum MDA levels, liver homogenates MDA levels decreased in all treated groups but a considerable decrease was not observed for DHMPC treated group. Liver homogenates glutathione (GSH) levels drastically decreased in hyperlipidemic group and increased in all treated groups. As a conclusion DHMPC displayed both antioxidant and lipid lowering effects and can be a candidate drug for further studies. © ECV Editio Cantor Verlag.Publication Metadata only Fluoride levels in various black tea, herbal and fruit infusions consumed in Turkey(PERGAMON-ELSEVIER SCIENCE LTD, 2009) YARAT, AYŞEN; Emekli-Alturfan, Ebru; Yarat, Aysen; Akyuz, SerapThe fluoride contents were determined by ion-selective electrode in 26 black tea samples originally produced in Turkey, Sri Lanka, India and Kenya, and in 14 herbal and seven fruit infusions originated from Turkey. Fluoride content in black tea infusions ranged from 0.57 to 3.72 mg/L after 5 min of brewing. Higher fluoride levels were found in black teas originated from Turkey when compared with teas originated from Sri Lanka. Moreover higher fluoride levels were determined in black tea bags compared with granular and stick-shaped black teas. However, herbal and fruit infusions were characterized by low values of fluoride (0.02-0.04 mg/L) after 5 min of brewing and increasing brewing time to 10 min caused only slight increases in some infusions. As a result, consuming tea infusions prepared from some black tea available in Turkish market, especially black tea bags, in large quantities may lead to exposion to a high amount of fluoride which may cause dental fluorosis. Although fruit and herbal infusions are safer to consume their fluoride contents are too low for caries prevention. In countries such as Turkey where tea is traditionally consumed, the fluoride concentration and daily safety precautions should be indicated on tea products. (C) 2009 Elsevier Ltd. All rights reserved.