Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Role of Ischemic Preconditioning and Tempol in Ischemia/Reperfusion

Injury In Isolated Rat Heart

Tempol (4-hydroxy-2,2,6,6-tetramethyl piperidine 1-oxyl) is a stable piperidine nitroxide (stable free radicals) of low molecular weight, which permeates the biologic membranes and behaves as superoxide dismutase (SOD) mimic. Studies have shown that tempol reduces reactive oxygene species production and apoptosis in cardiac cells, as well as injuries and dysfunctions which are induced by ischemia/reperfusion (I/R).

Many signaling pathways that take place in heart protection have been demonstrated by ischemic preconditioning (IPC) studies. Numerous studies have shown that IPC reduces injury followed by prolonged episodes of ischemia. Therefore, with this study, we aimed to investigate and compare the protective effect of either tempol administration or IPC which is induced by the short-term episode of I/R on I/R injury in isolated rat hearts.

In this study, hearts were attached to Langendorff isolated heart system with in situ cannulation method. A total of six experimental groups, each containing seven rats, were formed on the basis of different time points for control, I/R and IPC groups. All groups were studied in the presence or absence of tempol administration. Cardiodynamic parameters were recorded during the experiment. At the end of experiment, hearts were taken for biochemical analysis and all data were statistically evaluated.

In isolated rat hearts, while injuries caused by I/R have not changed during the experiment, a recovery was observed with implementation of IPC and tempol separately in perfusion pressure, end diastolic pressure, left ventricular developed pressure, heart rate, RPP which is an indicator of myocardial oxygen consumption, MaxdP/dt which is a parameter used to determine the ability of contractility of heart and contractility index parameters. However, among these groups, it was observed that there was a marked recovery in the group in which IPC was applied against to I/R injuries. Also, it was determined that tempol administration was partly effective on I/R injuries.

While there was a significant increment on creatine kinase-MB levels, which are used for showing cellular injuries, in I/R groups, IPC and tempol administration resulted an increase close to the value of the control group. Levels of lactate dehydrogenase, a marker of necrosis on tissues, showed a significant increment in I/R group, but implementation of IPC reduced I/R injuries, tempol administration possessing no effect. Levels of SOD, which is an antioxidant enzyme, decreased only in tempol group, and significantly increased in other groups, compared to the control group.

As a result, when cardiodynamic and biochemical data were evaluated collectively, it is revealed that ischemia/reperfusion leads to damage in heart tissue, IPC is more effective than tempol on prevention of this damage, and tempol administration partly provides benefit.

Six new compounds were synthesized with condensation reaction of 4-amino-3-mercapto-1,2,4-triazin-5(4H)-on with coumarin-3-carboxylic acid, 3-bromo-5-iodobenzoic acid, 2-bromo-5-chlorobenzoic acid, 5-chloro-2-methylbenzoic acid, 4-chloro-3,5-dinitrobenzoic acid, and 2 ,4,6-trichlorobenzoic acid in POCl_3. Structures of the synthesized compounds are characterized by IR, ¹H-NMR, ¹³C-NMR and MS.

KARADAĞ Seda
Tez Adı : Sinirli Ot (Plantago Lanceolata L.) Bitkilerinde Mikorizanın Kuraklık Toleransına Etkisi

Danışman : Doç. Dr. Gülriz BAYÇU KAHYAOĞLU

Prof. Dr. Wolfram BEYSCHLAG

Anabilim Dalı : Biyoloji

Programı (Varsa) : Botanik

Mezuniyet Yılı : 2013

Tez Savunma Jürisi : Doç. Dr. Gülriz BAYÇU KAHYAOĞLU

Prof. Dr. Nazlı ARDA

Prof. Dr. Orhan KÜÇÜKER

Prof. Dr. Gül CEVAHİR ÖZ

Y. Doç. Dr. Ergül ÇETİN