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    The attenuation of vasospasm by using a SOD mimetic after experimental subarachnoidal haemorrhage in rats
    (Springer Wien, 2003) Aladag, MA; Turkoz, Y; Sahna, E; Parlakpinar, H; Gul, M
    Background. Delayed cerebral vasoconstriction and brain ischemia, are critical problems in the management of a patient affected by rupture of an intracranial aneurysm. Overexpression of Cu-Zn superoxide dismutase (Cu-Zn SOD) can reduce the extent of cerebral vasospasm. We, therefore investigated if vasospasm, can be prevented by a novel, stable, and cell permeable SOD mimetic, MnTBAP [Mn(III) tetrakis (4-benzoic acid) porphyrin] which permeates the biological membranes and scavenges superoxide anions and peroxynitrite. Methods. 28 rats (225-250 g) were divided equally into four groups: group 1: control; group 2: SAH only; group 3: SAH plus placebo; and group 4: SAH plus MnTBAP We used a double haemorrhage method to produce SAH. Starting six hours after SAH, 5 mg/kg MnTBAP (Calbiochem, Darmstadt-Germany; Cat. No 475870)) or an equal volume of 0.9% saline (37degreesC) was administered by intraperitoneal injection twice daily for 5 days to groups 4 and 3 respectively. MnTBAP or 0.9% saline injections were continued up to fifth day after SAH and rats were sacrificied on the fifth day. Brain sections at the level of the pons were examined by light microscopy. Planimetric measurements were made for the cross-sectional areas of the lumen and the vessel wall (intima plus media) of the basilar artery by a micrometer. Finding. Administration of MnTBAP significantly attenuated the vasoconstriction of the basilar artery in group 4 compared with the groups 2 and 3 (p<0.001). Interpretation. These results suggest that this SOD mimetic (MnTBAP) attenuates delayed cerebral vasoconstriction following experimental SAH and that superoxide anions have a role in the pathogenesis of vasospasm after SAH.
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    Protective role of caffeic acid phenethyl ester in the liver of rats exposed to cold stress
    (Wiley-Blackwell, 2006) Ates, B; Dogru, MI; Gul, M; Erdogan, A; Dogru, AK; Yilmaz, I; Yurekli, M
    Cold exposure can induce a form of environmental stress. Cold stress (CS) alters homeostasis, results in the creation of reactive oxygen species and leads to alterations in the antioxidant defense system. The caffeic acid phenethyl ester (CAPE), an active component of propolis, has an antioxidant capacity. We investigated the effect of CS on oxidative stress and antioxidant defense system and the possible protective effect of CAPE in rat liver tissue. Twenty-four female Wistar Albino rats were divided into four groups: Control, CAPE-treated, CS, and CAPE-treated CS (CS + CAPE) group. Catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activities and total glutathione (GSH) and malondialdehyde (MDA) levels were measured. In addition, histological changes in liver tissue were examined by light microscopy. SOD, CAT and GSH-Px activities and total GSH level were significantly declined in the CS group. In the CS + CAPE group, the activities of these three enzymes and GSH level significantly raised with regard to the CS group. MDA levels increased in the CS group and decreased in the CS + CAPE group. The tissues of the CS group showed some histopathological changes such as necrosis, hepatocyte degeneration, sinusoidal dilatation, hemorrhage and vascular congestion and dilatation. In the CS + CAPE group, the histopathological evidence of hepatic damage was markedly reduced. Histological parameters were consistent with biochemical parameters. In this study, CS increased oxidative stress in liver tissue. CAPE regulated antioxidant enzymes, inhibited lipid peroxidation and reduced hepatic damage.