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Öğe Electron microscopic immunolocalization of basic fibroblast growth factor in peripheral nerves(Springer, 2000) Kayton, RJ; Aktas, RGIn spite of ample information about the distribution and the effects of basic fibroblast growth factor (bFGF) in the central nervous system, few data are available concerning the localization of this protein in the peripheral nervous system. In view of the role of bFGF in the regulation of trophic and non-trophic functions, we focused on the presence and precise localization of this growth factor in normal peripheral nerves at the electron microscopic level. The study shows that bFGF is mainly located in the Schwann cells, especially in the nuclei. There is slight labeling in the myelin sheath and in the axon cytoplasm. The study provides morphologic evidence for an association between bFGF expression and Schwann cells. Such an association argues for a role of this peptide in the maintenance or regeneration of peripheral nerves.Öğe Immunohistochemical demonstration of cytochrome oxidase in different parts of the central nervous system: A comparative experimental study(Blackwell Wissenschafts-Verlag Gmbh, 2000) Taskinalp, O; Aktas, RG; Cigali, B; Kutlu, AKCytochrome oxidase, the terminal enzyme of the electron transport chain, is a marker of the functional activity of the cell. In this study; localization of cytochrome oxidase in cerebrum, cerebellum, hippocampus, substantia nigra and choroid plexus of adult rats was investigated using immunohistochemical methods. Neural bodies were immunoreactive while neuroglial cells and axonal areas did not show significant immunostaining. The cerebral cortical substantia grisea region was stained almost homogeneously with cytochrome oxidase. In the cerebellar cortex, immunolabelling was more intense in the granular layer than the molecular layer. There was significant immunostaining in Purkinje cells. White matter, both in cerebrum and cerebellum, did not show immunoreactivity for cytochrome oxidase. Neurones in the hippocampus showed variable immunostaining; some of them were negative while others revealed high immunoreactivity. The neurones in substantia nigra were heavily labelled. Immunostaining for cytochrome oxidase in plexus choroideus epithelial cells was also remarkable. The morphological findings demonstrate the regions which most require and produce energy and reflect the differences in cellular activity in these parts of the central nervous system.Öğe Protective effect of melatonin on contractile activity and oxidative injury induced by ischemia and reperfusion of rat ileum(Pergamon-Elsevier Science Ltd, 2005) Ozacmak, VH; Sayan, H; Arslan, SO; Altaner, S; Aktas, RGFree radicals derived from molecular oxygen have been reported to be responsible for changes in motility and mucosal damage observed in intestinal ischemia-reperfusion injury. Melatonin has been considered as an antioxidant that prevents injuries resulted from I/R in various tissues. The present study was designed to determine the effect of melatonin on the contractile responses of acetylcholine (Ach) and KCl, on malondialdehyde (MDA), a product of lipid peroxidation, and reduced glutathione (GSH) levels and to assess histopathological changes in the smooth muscle of terminal ileum subjected to ischemia-reperfusion. The intestinal ischemia-reperfusion was induced by occlusion of superior mesenteric artery of rat for 30 min, followed by a period of reperfusion for 3 h. Melatonin at doses of 10 or 50 mg/kg was administered via the tail vein in 5 min prior to reperfusion. Following reperfusion, segments of terminal ileum were rapidly taken and transferred into isolated organ bath and responses to Ach and KCl were recorded. Samples of terminal ileum were also taken for measuring the MDA and GSH levels. EC50 values of these contracting substances were seriously reduced in the ischemia-reperfusion group compared to that of the sham-operated control group. The decreased contraction response to Ach and KCl was significantly ameliorated by a dosage of 50 mg/kg of melatonin, while not by a dosage of 10 mg/kg. Similar pattern of the effect was observed in the tissue levels of MDA and GSH as well as in histological improvement. Melatonin appeared to be restoring the amounts of tissue MDA and GSH back to about control levels. These results suggest that the high dose of melatonin not only physiologically but also biochemically and morphologically could be useful to normalize contractility injured by oxidative stress in intestinal ischemia-reperfusion. (C) 2004 Elsevier Inc. All rights reserved.Öğe Use of iodine-123 metaiodobenzylguanidine scintigraphy for the detection of amiodarone induced pulmonary toxicity in a rabbit model: a comparative study with technetium-99m diethyltriaminepenta acetic acid radioaerosol scintigraphy(Japanese Society Nuclear Medicine, 2005) Durmus-Altun, G; Altun, A; Aktas, RG; Salihoglu, YS; Yigitbasi, NOThe purpose of the study was; (i) to deter-mine whether I-123-MIBG scintigraphy is sensitive for detection of amiodarone induced pulmonary toxicity (AIPT) and (ii) to compare it with Tc-99m-DTPA radioacrosol. Twelve white New Zealand rabbit with initial mean body weight 4.24 +/- 0.47 g were divided into two groups. AIPT group (n = 7) was administered amiodarone (20 mg/kg BW). The control group (n = 5) received the same amount of 0.9% saline. All animals underwent I-123-MIBG and Tc-99m-DTPA radioaerosol scintigraphy at the end of the treatment period. I-123-MIBG static thorax images were obtained during 10 minutes at 15 minutes and 3-hours after 'intravenous injection of the radiopharmaccutical. Lung to heart ratios (LHR) and lung to mediastinum ratios (LMR), and retention index (LRI) of I-123-MIBG were determined. Two days after I-123-MIBG scintigraphy, 99mTc-DTPA radioaerosol scintigraphy was performed, and clearance from the lungs was measured for 10 min (1 min/frame) following termination of inhalation. I-123-MIBG lung retention index (LRI) was significantly higher in the AIPT group than the control (61 +/- 4.6 vs. 40 +/- 4.5, p = 0.01). Early LHR and LMR were significantly lower in the AIPT group than in the control group (p = 0.04, p = 0.01, respectively), whereas those of late LHR and LMR were not significantly different. T-1/(2) values of DTPA clearance were significantly increased in AIPT group according to the control group (55 +/- 7.2 vs. 86.6 +/- 18.5,p = 0.02). I-123-MIBG scintigraphy is a valuable tool for detecting AIPT in a rabbit model. Additionally, Tc-99m-DTPA radioaerosol scintigraphy is an excellent comprehensive investigational tool for detecting AIPT with the added advantage of lower cost.
