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Öğe Alfa lipoik asidin rat karaciğer homojenatlarında hidrojen peroksit ile indüklenmiş lipid peroksidasyonuna etkisi(2014) Eskiocak, Sevgi; Yapar, Süleyman BedirAmaç: Oksidan ürünlerin, diabetes mellitus, ateroskleroz, katarakt ve karaciğer sirozu gibi hastalıkların patogenezinde rol aldığı bilinmektedir. Bu nedenle son yıllarda antioksidan moleküllerin terapotik amaçlı kullanımı artmıştır.Çalışmamızda; alfa lipoik asidin farklı dozlarının invitro kullanımının, rat karaciğer homojenatlarında indüklenmiş lipid peroksidasyonu ve doku glutatyon düzeyine etkilerini araştırmak amaçlanmıştır.Metod: Rat karaciğer homojenatlarında 15 mM hidrojen peroksit kullanılarak lipid peroksidasyon indüksiyonu yapıldı. Lipid peroksidasyonu indüklenen deney düzenekleri 4 alt gruba ayrıldı ve bu gruplara sırasıyla 0, 2, 4 ve 8 mM alfa lipoik asid eklendi. Doku glutatyon düzeyleri ve lipid peroksidasyon son ürünü olan malondialdehid düzeyleri incelendi.Bulgular: Aktivasyon grubundaki malondialdehid düzeyi kontrol grubuna göre anlamlı yüksek bulundu. Tüm Alfa lipoik asid gruplarındaki malondialdehid düzeyleri aktivasyon grubunun düzeyine göre anlamlı düşük bulundu. Aktivasyon grubunun glutatyon düzeyi kontrol grubuna göre anlamlı düşük bulundu. Alfa lipoik asid gruplarındaki glutatyon düzeyleri aktivasyon grubundaki düzeye göre anlamlı yüksek bulundu. Glutatyon düzeyinin zamana bağlı değişimi incelendiğinde önce dereceli olarak azaldığı, daha sonra arttığı, 4 ve 8 mM gruplarında başlangıç düzeyini de aştığı gözlendi.Sonuç: Sonuç olarak bulgularımız, sadece hidrojen peroksit uygulanan aktivasyon grubunda lipid peroksidasyonunun uyarıldığını göstermektedir. Alfa lipoik asid uygulanan gruplardaki malondialdehid düzeylerinin aktivasyon gruplarındaki düzeylere göre anlamlı düşük, glutatyon düzeylerinin ise anlamlı yüksek olmasının nedeninin, alfa lipoik asid'in antioksidan özelliklerinden kaynaklandığını söyleyebilirizÖğe Asetaminofen ile toksik hepatit oluşturulan ratlarda L-karnitinin etkisi(2013) Aktaş, Özgür; Eskiocak, Sevgi; Özgün, Gülben Sayılan; Yalçın, Ömer; Süt, NecdetAmaç: Bu çalışmanın amacı, sıçanlarda asetaminofen ile oluşturulan toksik hepatitte Lipid peroksidasyonu ve oksidatif stresin yol açtığı karaciğer hasarına karşı L-karnitinin koruyucu etkisini incelemektir. Gereç ve Yöntem: Wistar albino erkek sıçanlar kontrol, toksik hepatit ve L-karnitin grubu olmak üzere rastgele 3 gruba ayrıldı. Toksik hepatit oluşturmak üzere toksik hepatit ve L-karnitin gruplarına tek doz ılık serum fizyolojikte çözünmüş asetaminofen (300 mg/kg) intraperitoneal olarak verildi. Toksik hepatit oluşturulduktan beş dakika sonra L-karnitin grubuna tek doz L-Karnitin (500 mg/kg) intraperitoneal olarak verildi. Kontrol grubuna tek doz ılık serum fizyolojik intraperitoneal olarak verildi.Bulgular: Kontrol grubu ile karşılaştırıldığında, toksik hepatit grubunda serum alanin ve aspartat aminotransferaz ve plazma ve karaciğer malondialdehit düzeyleri daha yüksek, oysa plazma Gc-globulin, tam kan ve karaciğer glutatyon düzeyleri, eritrosit ve karaciğer katalaz aktivitesi ve eritrosit glutayon peroksidaz aktivitesi daha düşüktü. Toksik hepatit grubu ile karşılaştırıldığında, L-karnitin grubunda serum alanin ve aspartat aminotransferaz ve plazma ve karaciğer malondialdehit düzeyleri daha düşük, oysa tam kan ve karaciğer glutatyon düzeyleri, eritrosit ve karaciğer katalaz aktivitesi ve eritrosit glutayon peroksidaz aktivitesi daha yüksekti. Bu grupların plazma Gc-globulin düzeyleri arasında anlamlı bir fark yoktu. Toksik hepatit grubundaki histopatolojik değişiklikler L-karnitin grubundakinden daha belirgindi.Sonuç: L-karnitin sıçanlarda asetaminofen ile oluşturulan toksik hepatitte lipid peroksidasyonu ve oksidatif stresin neden olduğu karaciğer hasarına karşı koruyucu etkiye sahiptirÖğe Biyokimyada nesnel yapılandırılmış pratik sınav (OSPE) deneyimi(2005) Çakır, Erol; Eskiocak, Sevgi; Gülen, Şendoğan; Gökmen, Süer Selma; Erbaş, HakanÖlçme ve değerlendirme eğitim sürecinin en önemli öğesidir. Öğrencinin kazanması gereken bilgiyi, beceriyi ve tutumu ne ölçüde kazanmış olduğunun en tarafsız ve adil biçimde değerlendirilmesi gereği; bizi öğrenciyi çevresel faktörlerden uzak, iki gözlemcinin önünde müdahalesiz ve tarafsız olarak değerlendirebilen nesnel yapılandırılmış pratik sınavı uygulamasını başlatmaya yönlendirmiştir. Bu çalışmada; Trakya Üniversitesi Tıp Fakültesi Biyokimya Anabilim Dalında dönem I öğrencilerine uygulanan nesnel yapılandırılmış pratik sınavı sonuçlarını tanıtmak amaçlanmıştır. Sınavda toplam 9 durak oluşturuldu. Her durak için öğrencilere yönerge hazırlandı. Yönergelerde öğrenciden ne yapmaları beklendiği bilgisinin yanı sıra, duraktaki işlemleri yaparken yaptığını yüksek sesle ifade etmesi istendi. Ayrıca eğiticilere de her bir duraktaki değerlendirmeyi nasıl yapacaklarını gösteren yönergeler hazırlanarak sınav öncesi prova yapıldı. Testlerin hangi durum/hastalıklarda ne istenmesi/yapılması gerektiğini bilme, çözelti kavramlarını anlama, reaktiflerin hangi analizde kullanıldıklarını bilme becerilerinin iyi düzeyde olduğu görüldü. Öğrencilerin en zayıf oldukları durumun, test sonucunu değerlendirme ve yanlış sonuca yol açan durumları bilme becerisi olduğu tespit edildi. Yapılandırılmış pratik sınavın bölümümüz için en büyük kazancı, beceri soruları için kontrol listelerinin hazırlanmış olmasıdır. Eğitim amaç-hedefimize uygun, nesnel güvenilir, adil bir pratik sınav sistemi oluşturulmuştur. Sınav sonuçları bir sonraki yıllardaki pratik eğitimimizi şekillendirmemizde de rehber rol oynamıştır.Öğe Caffeine Increases Apolipoprotein A-1 and Paraoxonase-1 but not Paraoxonase-3 Protein Levels in Human-Derived Liver (HepG2) Cells(2017) Özgün, Gülben Sayılan; Özgün, Eray; Tabakçıoğlu, Kıymet; Gökmen, Selma Süer; Eskiocak, Sevgi; Çakır, ErolBackground: Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 are antioxidant and anti-atherosclerotic structural high-density lipoprotein proteins that are mainly synthesized by the liver. No study has ever been performed to specifically examine the effects of caffeine on paraoxonase enzymes and on liver apolipoprotein A-1 protein levels. Aims: To investigate the dose-dependent effects of caffeine on liver apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 protein levels. Study Design: In vitro experimental study. Methods: HepG2 cells were incubated with 0 (control), 10, 50 and 200 ?M of caffeine for 24 hours. Cell viability was evaluated by 3-(4,5-Dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide assay. ApolipoproteinA-1, paraoxonase-1 and paraoxonase-3 protein levels were measured by western blotting. Results: We observed a significant increase on apolipoprotein A-1 and paraoxonase-1 protein levels in the cells incubated with 50 µM of caffeine and a significant increase on paraoxonase-1 protein level in the cells incubated with 200 µM of caffeine. Conclusion: Our study showed that caffeine does not change paraoxonase-3 protein level, but the higher doses used in our study do cause an increase in both apolipoprotein A-1 and paraoxonase-1 protein levels in liver cellsÖğe Comparison of the protective roles of L-carnitine and amifostine against radiation-induced acute ovarian damage by histopathological and biochemical methods(Medknow Publications & Media Pvt Ltd, 2015) Yurut-Caloglu, Vuslat; Caloglu, Murat; Eskiocak, Sevgi; Tastekin, Ebru; Ozen, Alaattin; Kurkcu, Nukhet; Oz-Puyan, FulyaPurpose: The aim of this study was to compare the radioprotective efficacies of L-carnitine (LC) and amifostine against radiation-induced acute ovarian damage. Materials and Methods: Forty-five, 3-month-old Wistar albino rats were randomly assigned to six groups. Control (CONT, n = 7); irradiation alone RT: radiation therapy (RT, n = 8); amifostine plus irradiation (AMI + RT, n = 8); LC plus irradiation (LC + RT, n = 8); LC and sham irradiation (LC, n = 7); and amifostine and sham irradiation (AMI, n = 7). The rats in the AMI + RT, LC + RT and RT groups were irradiated with a single dose of 20 Gy to the whole abdomen. LC (300 mg/kg) and amifostine (200 mg/kg) was given intraperitoneally 30 min before irradiation. Five days after irradiation, both antral follicles and corpus luteum in the right ovaries were counted, and tissue levels of malondialdehyde (MDA) and advanced oxidation protein product (AOPP) were measured. Results: Irradiation significantly decreased antral follicles and corpus luteum (P:0.005 and P < 0.0001). LC increased the median number of antral follicles and corpus luteum (P:0.009 and P < 0.0001, respectively). Amifostine improved median corpus luteum numbers but not antral follicle (P < 0.000, P > 0.05). The level of MDA and AOPP significantly increased after irradiation (P = 0.001 and P < 0.0001, respectively). MDA and AOPP levels were significantly reduced by LC (P:0.003, P < 0.0001) and amifostine (P < 0.0001, P:0.018). When comparing CONT group with AMI + RT and LC + RT groups, MDA and AOPP levels were similar (P > 0.005). The levels of both MDA and AOPP were also similar when LC + RT is compared with AMI + RT group (P > 0.005). Conclusions: L-carnitine and amifostine have a noteworthy and similar radioprotective effect against radiation-induced acute ovarian toxicity.Öğe Deneysel kolitte L-karnitinin serum paraoksonaz, arilesteraz ve laktonaz aktivitelerine ve oksidatif duruma etkisi(2013) Özgün, Eray; Gökmen, Selma Süer; Yalçın, Ömer; Eskiocak, Sevgi; Özgün, Gülben SayılanAmaç: Oksidatif stres inflamatuvar barsak hastalıklarının patogenezinde önemli rol oynar. Bu çalışmada, antioksidan L-karnitinin deneysel kolitte, kolonda da sentez edilen paraoksonaz 1 enzim aktivitelerine ve oksidatif duruma etkisini inceledik.Gereç ve Yöntem: Wistar albino dişi sıçanlar kontrol, kolit, ön tedavi ve tedavi olmak üzere rastgele dört gruba ayrıldı. Kolit oluşturmak için kolit, tedavi ve ön tedavi gruplarına tek doz 1 mL asetik asit (%4) intrarektal olarak uygulandı. Ön tedavi grubuna kolit oluşturulmadan 1 saat önce, tedavi grubuna ise kolit oluşturulduktan 24 saat sonra 500 mg/kg L-karnitin tek doz halinde intraperitoneal olarak verildi. Tüm gruplar intrarektal uygulamadan 48 saat sonra sakrifiye edildi. Kolit varlığı histopatolojik olarak gösterildi. Serumda paraoksonaz, arilesteraz ve laktonaz aktiviteleri, total oksidan ve antioksidan durum, malondialdehit ve total sialik asit ölçüldü. Oksidatif stres indeksi formülden hesaplandı.Bulgular: Asetik asitle kolit oluşturulan grupta serum malondialdehit, total sialik asit, total oksidan durum ve oksidatif stres indeksi anlamlı olarak artarken, paraoksonaz, arilesteraz ve laktonaz aktiviteleri ve total antioksidan durum anlamlı olarak azaldı. L-Karnitin malondialdehit, total sialik asit, total oksidan durum ve oksidatif stres indeksinde anlamlı bir azalmaya yol açarken, sadece tedavi grubunun serum arilesteraz ve laktonaz aktivitelerinde anlamlı bir artışa yol açtı.Sonuç: Asetik asitle oluşturulan deneysel kolitte L-karnitin, arilesteraz ve laktonaz aktivitelerini arttırıcı, oksidatif stresi azaltıcı bir etkiye sahiptir. Bu nedenle L-karnitin, inflamatuvar barsak hastalıklarının tedavisinde yararlı olabilirÖğe The Diagnostic Value of Oxidative Stress Products in Pulmonary Embolism(Bilimsel Tip Publishing House, 2011) Batmaz, Emrah; Edis, Ebru Cakir; Eskiocak, Sevgi; Hatipoglu, Osman Nuri; Kaya, SabriyeObjective: The aim of our study is to show the oxidative stress in pulmonary embolism by detecting the levels of ischemia modified albumin (IMA), advanced oxidation protein product (AOPP) and malondialdehyde (MDA) in patients with pulmonary embolism. Material and Method: 39 patients, who were dagnosed with pulmonary embolism in the Emergency Service or Thoracic Diseases Polyclinic of the Trakya University Faculty of Medicine between September 1, 2008 and March 31, 2009, and 39 healthy volunteers were included in the study. IMA, AOPP and MDA levels were studied. T-test and Mann Whitney and X-2 tests were applied in independent samples. A value of p<0.05 was accepted as statistically significant. Results: There was no significant difference between the two groups in terms of age, height, and weight. The difference in the AOPP levels of the two groups was not significant. The difference in the serum albumin levels of the two groups was found significant (p<0.001). The difference in levels of IMA after being corrected according to the albumin levels of the two groups was not significant. MDA levels of the two groups showed a significant difference (p=0.032). Conclusion: AOPP levels in patients with pulmonary embolism were not found different but, the increases of MDA levels were significant. We suggest using albumin-adjusted IMA levels to interpret IMA levels more correctly. We need more studies about using IMA levels as an indicator for diagnosis of pulmonary embolism.Öğe Diyabetik Sıçanlarda Taurinin Paraoksonaz, Arilesteraz ve Laktonaz Aktivitelerine Etkileri(2016) Süt, Necdet; Akıncı, Mehmet; Gökmen, Selma Süer; Eskiocak, Sevgi; Özgün, Eray; Özgün, Gülben SayılanAmaç: Bu çalışmanın amacı streptozotosin ile oluşturulan deneysel diyabette taurinin plazmaparaoksonaz, arilesteraz ve laktonaz aktivitelerine etkisini araştırmaktır.Materyal ve Metod: Vücut ağırlıkları 204±11 g olan otuz altı adet Sprague-Dawley cinsi dişi sıçan,kontrol, taurin, diyabet ve diyabet+taurin olmak üzere rastgele ve eşit sayıda dört gruba ayrıldı. Diyabetoluşturmak için diyabet grubuna ve diyabet+taurin grubuna streptozotosin (40 mg/kg) intraperitonealolarak enjekte edildi. Taurin (%1), taurin grubu ve diyabet+taurin grubunun içme suyuna 21 günboyunca eklendi. Plazma paraoksonaz, arilesteraz ve laktonaz aktiviteleri, malondialdehit ve HDLkolesterol düzeyleri ölçüldü.Bulgular: Kontrol grubu ile karşılaştırıldığında diyabet grubunda plazma paraoksonaz, arilesteraz velaktonaz aktiviteleri ve HDL kolesterol düzeyleri anlamlı olarak azalırken malondialdehit düzeylerianlamlı olarak arttı. Taurin tedavisi, streptozotosin ile diyabet oluşturulan sıçanlarda plazmaparaoksonaz, arilesteraz ve laktonaz aktivitelerinde anlamlı bir artışa ve plazma malondialdehitdüzeylerinde anlamlı bir azalmaya yol açtı.Sonuç: Çalışmamız taurinin, streptozotosin ile deneysel diyabet oluşturulan sıçanlarda plazmaparaoksonaz, arilesteraz ve laktonaz aktivitelerini arttırıcı etkiye sahip olduğunu gösterdi. Taurin,diyabetin aterosklerotik komplikasyonlarının önlenmesinde yararlı olabilir.Öğe The effect of alpha lipoic acid on hydrogen peroxide-induced lipid peroxidation in rat liver homogenates(Turkish Biochem Soc, 2014) Yapar, Suleyman Bedir; Eskiocak, SevgiObjective: It is known that oxidant species play a role in the pathogenesis of certain diseases such as diabetes mellitus, atherosclerosis, cataract and hepatic cirrhosis. Therefore, the use of antioxidant species for therapeutic purposes has risen up in the recent years. The aim of the study was to investigate the different concentrations of alpha lipoic acid on the induced lipid peroxidation and tissue glutathione level in rat liver homogenates. Methods: Hydrogen peroxide (15 mM) has been used for induction of lipid peroxidation at liver homogenates. The experimental setups induced by lipid peroxidation have been divided into four sub-groups. Alpha lipoic acid was added in 0, 2, 4 and 8 mM concentrations into those groups, respectively. The malondialdehyde levels which is the end product of lipid peroxidation and the levels of tissue glutathione have been determined. Results: The level of malondialdehyde in the activation groups has been found to be significantly higher than to the control group. The levels of malondialdehyde in the all alpha lipoic acid groups have been found to be significantly lower than the activation group. The level of glutathione in the activation group has been detected significantly lower when it was compared to the control group. The levels of glutathione in the all alpha lipoic acid groups have been found to be significantly higher from the activation group. When the time-dependent change in the level of glutathione was investigated it was observed that these initially decrease and then started to increase. In the groups of 4 and 8 mM, this level was even over from the starting point. Conclusion: In conclusion, our findings suggest that lipid peroxidation is induced in the experimental setups where hydrogen peroxide are applied. The reason of significantly lower malondialdehyde and higher glutathione levels in alpha lipoic acid group than activation groups may be a result of the antioxidant property of alpha lipoic acid.Öğe The effect of L-carnitine on nitric oxide metabolism in streptozotocin-induced diabetic rats(Walter De Gruyter Gmbh, 2014) Ozgun, Gulben Sayilan; Ozgun, Eray; Eskiocak, Sevgi; Sut, NecdetObjective: The aim of this study is to investigate the effect of L-carnitine on plasma and liver nitric oxide metabolism in streptozotocin-induced diabetic rats. Methods: Sprague Dawley female rats were divided randomly into following groups: control, L-carnitine, diabetes and diabetes+L-carnitine. Diabetes and diabetes+L-carnitine groups were intra-peritonally injected with a single dose of streptozotocin (40 mg/kg) prepared in the citrate buffer (pH 4.5). Other groups were injected with only citrate buffer. 72 hours after the streptozotocin injection, L-carnitine (500 mg/kg/day) was given intraperitoneally to L-carnitine and diabetes+L-carnitine groups for 15 days. Physiological saline was given intraperitoneally to the other groups for 15 days. Blood sugar (at 72 hours and the end of experiment), liver nitric oxide and inducible nitric oxide synthase, plasma nitric oxide and nitrotyrosine levels were measured. Results: Blood glucose levels in diabetic groups were higher compared with other groups. Percentage change of blood glucose in diabetes+L-carnitine group was lower compared with other groups. Also diabetes+L-carnitine group's plasma nitric oxide levels were higher than control group. Plasma nitrotyrosine levels of L-carnitine injected groups were lower than diabetes group. There was no significant difference between the levels of liver inducible nitric oxide synthase and nitric oxide in groups. Conclusion: As a result, our study showed that plasma and liver nitric oxide and liver inducible nitric oxide synthase levels aren't changed significantly but plasma nitrotyrosine levels are increased at the end of 15th day of experimental diabetes. On the other hand, our results also showed that L-carnitine causes an increase in plasma nitric oxide levels and a decrease in plasma nitrotyrosine levels whereas it has no effect on liver nitric oxide and inducible nitric oxide synthase levels.Öğe Effect of L-carnitine on serum paraoxonase, arylesterase and lactonase activities and oxidative status in experimental colitis(Walter De Gruyter Gmbh, 2013) Ozgun, Eray; Ozgun, Gulben Sayilan; Eskiocak, Sevgi; Yalcin, Omer; Gokmen, Selma SuerAim: Oxidative stress plays an important role in the pathogenesis of inflammatory bowel disease. We investigated antioxidant L-carnitine effect on activities of paraoxonase 1 enzyme which is also synthesized in colon and oxidative status in experimental colitis. Material and Methods: Wistar albino female rats were divided into four groups randomly: control, colitis, pre-treatment and treatment groups. To induce colitis, single dose of 1 mL acetic acid (%4) was given intrarectally to colitis, pre-treatment and treatment groups. Single dose of 500 mg/kg L-carnitine was given intraperitoneally 1 hour before inducing colitis to pre-treatment group and 24 hours after inducing colitis to treatment group. All groups were sacrificied 48 hours after intrarectally administration. Existence of colitis was confirmed by histopathological changes. Paraoxonase, arylesterase and lactonase activities, total oxidant and antioxidant status, malondialdehyde, and total sialic acid were measured in serum. Oxidative stress index was calculated from the formula. Results: While serum malondialdehyde, total sialic acid, total oxidant status and oxidative stress index were significantly elevated, serum paraoxonase, arylesterase and lactonase activities and total antioxidant status were significantly decreased in acetic-acid induced experimental colitis. In acetic-acid induced experimental colitis, L-carnitine caused a significant decrease in serum malondialdehyde, total sialic acid, total oxidant status and oxidative stress index but a significant increase in serum arylesterase and lactonase activities of treatment group only. Conclusion: L-Carnitine has an increasing effect on serum arylesterase and lactonase activities and decreasing effect on oxidative stress in acetic acid-induced experimental colitis. Therefore, L-carnitine may be useful for the treatment of inflammatory bowel disease.Öğe Effect of Lidocaine on Reducing Injury in a Rat Electrical Burn Model(Lippincott Williams & Wilkins, 2012) Benlier, Erol; Eskiocak, Sevgi; Puyan, Fulya Oz; Sikar, Emel Yurdakul; Kandulu, Huseyin; Omurlu, Imran Kurt; Top, HusamettinElectrical injuries induce progressive tissue loss. We evaluated the effect of lidocaine on tissue necrosis after electrical burn injuries. Forty-two male Wistar albino rats (250-300 g) were divided into 3 groups [Group A (n = 6), control group without an electrical burn injury; and Groups B (n = 18) and C (n = 18), electrical burn injury groups without and with lidocaine therapy, respectively]. Three separate analyses were performed at different time points on 6 of 18 rats from Groups B and C at each time point. Electrical burns were induced by applying 220 V AC between the left upper and right lower extremities for 10 seconds. Myeloperoxidase and malondialdehyde levels were measured in skin and muscle biopsy specimens after the first hour, fresh and dry weight differences in the amputated extremities were calculated after 24 hours, and live and necrotic tissue areas were measured at 7 days after burn injury. We found that lidocaine reduced edema, the number of neutrophils, and neutrophil damage in tissues. We conclude that lidocaine decreased the amount of necrotic tissue caused by electric injury.Öğe Effect of lipoic acid on paraoxonase-1 and paraoxonase-3 protein levels, mRNA expression and arylesterase activity in liver hepatoma cells(General Physiol And Biophysics, 2017) Ozgun, Eray; Ozgun, Gulben Sayilan; Tabakcioglu, Kiymet; Gokmen, Selma Suer; Sut, Necdet; Eskiocak, SevgiParaoxonase-1 (PON1) and paraoxonase-3 (PON3) are anti-atherosclerotic enzymes, synthesized primarily in liver and bound to HDL in circulation. The aim of the present study was to investigate the effects of therapeutic doses of lipoic acid on PON1 and PON3 protein levels, mRNA expression and arylesterase activity in liver. We treated HepG2 cells with 10, 40 and 200 mu M lipoic acid for 72 h. Cell viability was evaluated by 3-(4,5-dimethy1-2-thiazoly1)-2,5-dipheny1-2Htetrazolium bromide assay. PON1 and PON3 protein levels were measured by Western blotting, their mRNA expression was measured by quantitative PCR and arylesterase activity was measured spectrophotometrically. 200 mu M lipoic acid caused a significant increase on PON1 and PON3 protein levels and arylesterase activity as compared with control, 10 mu M and 40 mu M lipoic acid treated cells. 200 mu M lipoic acid also caused a significant decrease on PON1 mRNA expression whereas on a significant increase PON3 mRNA expression as compared with control, 10 mu M and 40 mu M lipoic acid-treated cells. Our study showed that although lip oic acid up-regulates PON3 but down-regulates PON1 mRNA expression, it increases both PON1 and PON3 protein levels and arylesterase activity in HepG2 cells. We can report that lipoic acid may be useful for preventing atherosclerosis at therapeutic doses.Öğe The effect of melatonin on protein oxidation and nitric oxide in the brain tissue of hypoxic neonatal rats(Elsevier, 2007) Eskiocak, Sevgi; Tutunculer, Filiz; Basaran, Umit Nusret; Taskiran, Ali; Cakir, ErolMelatonin is a potent antioxidant agent that can scavenge oxy- and nitroradicals generated under hypoxic conditions in the brain. In this study, we investigated the effect of melatonin on protein oxidation and nitric oxide (NO) during hypoxia. Seven-day-old Sprague-Dawley newborn rats were divided into three groups. Hypoxic (n = 9) and melatonin (n = 11) groups were subjected to 2 h of hypoxic exposure (a humidity mixture of gases consisting of 92% nitrogen and 8% oxygen). Melatonin (at a dose of 10 mg/kg) was administrated 30 min before the onset hypoxia and then at 24th and 48th hours after the end of the hypoxic exposure. Control (n = 10) and hypoxic groups received the isotonic sodium chloride according to the same schedule. The brain tissue concentration of advanced oxidation protein products (AOPP) and protein thiol (P-SH) was used as an index of protein oxidation. In our study, although AOPP and NO increased significantly, the levels of P-SH decreased in the hypoxic group. The level of AOPP was declined by melatonin treatment. However, perturbed thiol status could not be recovered by melatonin treatment. There was no relationship between the levels of NO and protein oxidation markers. These results indicate that exogenous melatonin could prevent AOPP, but that it is inadequate in recovering perturbed thiol status. Therefore, melatonin alone was observed to be an incomplete treatment to prevent protein oxidation in hypoxia-induced brain damage. (c) 2006 Elsevier B.V. All rights reserved.Öğe THE EFFECT OF MENTAL STRESS ON SEMINAL MDA AND SEMEN PARAMETERS(Aves, 2005) Gozen, A. Serdar; Eskiocak, Sevgi; Kilic, A. Serkan; Molla, SabahatIntroduction: The prevalence of unexplained infertility is 15% among all infertility cases and mental distress has been suggested as a cause of it. Emotional stress can cause some abnormalities in semen parameters, although the basic biochemical principles of the relationship between mental stress and semen parameters are poorly understood. Recently there is emerging interest in reactive oxygen species (ROS) with respect of their unfavorable effect on fertility as a result of lipid peroxidation. In this study, the effects of mental stress on the Malondialdehyde (MDA) levels, an indirect indicator of lipid peroxidation and semen parameters were investigated. Materials and Methods: Semen samples were collected from 36 healthy volunteer students of the fourth semester of the medical school just before (stress period) and 3 months after (non-stress period) the final examinations by masturbation. Psychological stress of the participants was measured with the State Trait Anxiety Inventory. After standard semen analysis, MDA activity was measured in the seminal plasma. The data of the stress and non-stress periods were compared via paired samples t test. Correlation analysis between MDA levels and sperm parameters was made for both stress and non-stress periods. A value of p less than 0.05 was considered statistically significant. Correlations between MDA levels and sperm parameters also were examined by Pearson Correlation test. A value of p less than 0.05 was considered statistically significant. Results: During the stress period, stress scores were higher compared with the non-stress period (43.61 +/- 10.71 vs. 37.67 +/- 9.61). Our data showed that, sperm count, percentage of progressive motility and percentage of normal morphology significantly decreased during the stress period. Seminal plasma MDA levels were significantly higher during the stress period compared with the non-stress period (50.19 +/- 48.22 vs. 16.19 +/- 22.59 nmol/10(9) spermatazoa). There was a positive correlation between seminal plasma MDA levels and percentage immobility at 1/2 and 2nd hours at the stress period. And seminal plasma MDA level was found to correlate negatively with the percentage normal morphology and total sperm count. Conclusion: Our results indicate that mental stress can cause an unfavorable effect on semen parameters. Increased seminal plasma MDA levels at stress period may be a result of overproduction of ROS in semen. We would suggest that stress may cause oxidative stress in semen and in this way it could be responsible for male subfertility. We think that this subject deserves further studies.Öğe The Effect of N-acetylcysteine on Brain Tissue of Rats Fed with High-Cholesterol Diet(Walter De Gruyter Gmbh, 2008) Eskiocak, Sevgi; Altaner, Semsi; Bayir, Serpil; Cakir, ErolObjectives: The effect of N-acetylcysteine in rats fed a high-cholesterol diet on oxidative stress in the plasma and brain tissue of rats was investigated. Methods: The animals were maintained on a basal diet (control, n=10) or a high-cholesterol diet (1 % w/w) for eight weeks. The rats fed high-cholesterol diet were separated to three group; high-cholesterol diet (n=10), low N-acetylcysteine (n=10) and high N-acetylcysteine groups (n=9). Low and high N-acetylcysteine groups received N-acetylcysteine at a dose of 50 and 100 mg/kg/day respectively via intraperitoneally for eight weeks. Malondialdehyde, glutathione, nitric oxide, cholesterol and triglyceride levels were analyzed in the samples. The results were analyzed by Kruskal-Wallis variance analysis and then a Mann-Whitney U test. Results: When N-acetylcysteine was administered at a low dose, lipid peroxidation products in the brain significantly decreased compared with the high-cholesterol group, while glutathione content enhanced. On the other hand, when N-acetylcysteine was administered at a high dose, lipid peroxidation products in the brain and plasma significantly increased compared with the control group. Conclusions: These results suggest that N-acetylcysteine has a dual effect. If the N-acetylcysteine dose was carefully selected, N-acetylcysteine may have a neuroprotective effect against oxidative stress and hypercholesterolemia.Öğe Effect of palmitate-induced steatosis on paraoxonase-1 and paraoxonase-3 enzymes in human-derived liver (HepG2) cells(2019) Eskiocak, Sevgi; Özgün, Eray; Özgün, Gülben Sayılan; Tabakçıoğlu, Kıymet; Gökmen, Selma SüerAim: Palmitate is one of the most abundant fatty acid in both liver of healthy individuals and in patients with non-alcoholic fatty liver disease. Palmitate-induced steatosis in HepG2 cells is an in vitro non-alcoholic fatty liver disease model to investigate acute harmful effects of fat overaccumulation in the liver. Non-alcoholic fatty liver disease is strongly associated with atherosclerosis. Paraoxonase-1 and paraoxonase-3 are anti-atherosclerotic enzymes which are bound to high density lipoprotein in circulation and they are primarily synthesized by liver. There is no study that investigated the effect of palmitate-induced steatosis on paraoxonase-1 and paraoxonase-3 enzymes. The aim of present study was to investigate the effect of palmitate-induced steatosis on paraoxonase-1 and paraoxonase-3 enzymes in HepG2 cells. Methods: To induce steatosis, cells were incubated with 0.4, 0.7 and 1 mM palmitate for 24 hours. Cell viability was evaluated by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Cells were stained with oil red O and triglyceride levels were measured. Paraoxonase-1 and paraoxonase-3 protein levels were measured by western blotting, their mRNA expression were measured by quantitative PCR and arylesterase activity was measured spectrophotometrically. Results: All palmitate concentrations caused a significant increase on paraoxonase-1 mRNA levels. Palmitate concentrations did not cause a significant change on paraoxonase-1 and paraoxonase-3 protein levels, paraoxonase-3 mRNA levels and arylesterase activities. Conclusion: Our study showed that palmitate-induced steatosis up-regulates paraoxonase-1 mRNA, has no effect on paraoxonase-1 and paraoxonase-3 protein levels, paraoxonase-3 mRNA and arylesterase activity in HepG2 cells.Öğe The effects of L-carnitine on acetaminophen induced hepatotoxicity in rats(Walter De Gruyter Gmbh, 2013) Aktas, Ozgur; Eskiocak, Sevgi; Ozgun, Gulben Sayilan; Yalcin, Omer; Sut, NecdetObjective: The aim of this study was to investigate the protective effect of L-carnitine against to liver damage caused by lipid peroxidation and oxidative stress in toxic hepatitis induced by acetaminophen. Materials and Methods: Wister-albino male rats were divided into three groups randomly: control, toxic hepatitis, and L-carnitine groups. To introduce a toxic hepatitis, single dose of acetaminophen (300 mg/kg) dissolved in warm saline was given intraperitoneally to toxic hepatitis and L-carnitine groups. A single dose of L-carnitine (500 mg/kg) was given intraperitoneally to L-carnitine group five minutes after introducing to toxic hepatitits. A single dose of warm saline was given intraperitoneally to control group. Results: In toxic hepatitis group, serum alanine and aspartate aminotransferase and plasma and liver malondialdehyde levels were higher whereas plasma Gc-globulin, whole blood and liver glutathione levels, erythrocyte and liver catalase activities and erythrocyte glutathione peroxidase activity were lower as compared to control group. In L-carnitine group, serum alanine and aspartate aminotransferase and plasma and liver malondialdehyde levels were lower whereas whole blood and liver glutathione levels, erythrocyte and liver catalase activities and erythrocyte glutathione peroxidase activity were higher as compared to toxic hepatitis group. There was no significant change between plasma Gc-Globulin levels of these groups. Histopathological changes in toxic hepatitis group were more prominent than those found in L-carnitine group. Conclusion: L-Carnitine has a protective effect against to liver damage caused by lipid peroxidation and oxidative stress in toxic hepatitis induced by acetaminopfen in rats.Öğe The Effects of L-Carnitine on Protein Oxidation of Streptozotocin-Induced Diabetic Rats(Walter De Gruyter Gmbh, 2010) Ozgun, Gulben Sayilan; Eskiocak, Sevgi; Sut, NecdetIt has been reported that there is a significant protein oxidation resulted from oxidative damage in patients with diabetes mellitus. The aim of this study is to investigate the effects of L-carnitine which has antioxidant activity on protein oxidation seen in diabetes. In the study, twenty adult male rats of Wistar strain were randomly divided into three groups as follows: control (n=5), diabetes (n=8) and L-carnitine+diabetes groups (n=7). Diabetes and L-carnitine+diabetes groups were intraperitonally injected with a single dose of 50 mg/kg streptozotocin prepared in the citrate buffer (pH 4.5). Control group was injected with only citrate buffer. 72 hours after the streptozotocin injection, L-carnitine was given intraperitonally (500 mg/kg/day) to L-carnitine+diabetes groups for 15 days. Physiological saline was given intraperitonally to other groups for 15 days. The levels of blood sugar (at 72 hours and 2(nd) week) and kidney tissue advanced oxidation protein products of diabetes and L-carnitine+diabetes groups were higher than those in control group (p<0.001, p<0.05 and p<0.01; respectively). Kidney protein carbonyl level of diabetes group was higher when compared with the control group and L-carnitine+diabetes group (p<0.01 for both). There was a significant positive correlation between kidney tissue total and protein thiol levels in all groups. As a result; we can report that L-carnitine partially prevents protein oxidation seen in diabetes mellitus.Öğe Fucoidin, a neutrophil rolling inhibitor, reduces damage in a rat electrical burn injury model(Elsevier Sci Ltd, 2011) Benlier, Erol; Eskiocak, Sevgi; Puyan, Fulya Oz; Kandulu, Huseyin; Unal, Yasin; Top, Husamettin; Aygit, Ahmet CemalBackground: Electrical injuries induce progressive tissue loss caused by free oxygen radicals released from neutrophil aggregates. Fucoidin, a potent inhibitor of L-selectin function, reduces the aggregation of neutrophils. The aim of this study was to evaluate the effect of fucoidin on tissue damage in rat electrical burn injury model. Methods: Forty-two male Wistar albino rats (250-300 g) were divided into 3 groups (Group A (n = 6), control group without electrical burn injury; Groups B (n = 18) and C (n = 18), electrical burn injury groups without and with fucoidin therapy, respectively). Three separate analyses were performed at different time points on 6 out of 18 mice from Group B and C at each time point. Biochemistry (myeloperoxidase and malondialdehyde levels) and histopathology (number of neutrophils) of the skin and muscle biopsies at 1st hour; tissue edema (ratio of wet weight/dry weight of extremities) at 24th hour; and necrotic areas at 7th day after electrical injury were evaluated. The electrical burn was induced by exposing rats to 220 V AC between their left upper extremity and right lower extremity for 10 s. Fucoidin was administered as 25 mg/kg intravenous bolus injection at 15 mm after electrical burn injury. Results: Myeloperoxidase and malondialdehyde levels, number of neutrophils, tissue edema, and necrotic area were significantly less in fucoidin-applied rats than the group without fucoidin therapy. Conclusions: Fucoidin inhibits tissue damage induced by electrical burn injury in rats by reducing necrotic area, edema and number of neutrophils. (C) 2011 Elsevier Ltd and ISBI. All rights reserved.
