Browsing by Author "Öztürk, G"

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The Effect of Ginkgo Extract Egb761 in Cisplatin-Induced Peripheral Neuropathy in Mice
(Academic Press inc Elsevier Science, 2004) Öztürk, G; Anlar, Ö; Erdogan, E; Kösem, M; Özbek, H; Türker, A
Neuroprotective effect of Ginkgo biloba extract EGb761 in cisplatin (cis-diamminedi-chloroplatinum, or CDDP)-induced peripheral neuropathy was investigated. Swiss albino mice were treated with CDDP, 2 mg/kg ip twice a week for nine times. One group of the animals also received EGb761 in the drinking water at an estimated dosage of 100 mg/kg per day. Two other groups received vehicle (control) or EGb761 only. Development of neuropathy was evaluated with changes in sensory nerve conduction velocity (NCV). Following the treatments, dorsal root ganglia (DRGs) were microscopically examined and some were cultured for 3 days. EGb761 proved effective in preventing the reduction in NCV (P < 0.0001) caused by CDDP. CDDP caused a decrease in the number of migrating cells (P < 0.01) and in the length of outgrowing axons (P < 0.01) while EGb761 treatment prevented the latter. CDDP led to smaller nuclear and somatic sizes in neurons (P < 0.01), while with EGb761 co-administration, both were close to control values. Animals having EGb761 only had similar results with controls. In conclusion, EGb761 was found to be effective in preventing some functional and morphological deteriorations in CDDP-induced peripheral neuropathy. (C) 2004 Elsevier Inc. All rights reserved.
Effect of Leukemia Inhibitory Factor in Experimental Cisplatin Neuropathy in Mice
(Academic Press Ltd- Elsevier Science Ltd, 2005) Öztürk, G; Erdogan, E; Anlar, Ö; Kösem, M; Taspinar, M
In this study, the effect of leukemia inhibitory factor (LIF) on cisplatin (CDDP)-induced neuropathy was evaluated. Mice were treated with CDDP, 2 mg/kg i.p. twice a week nine times. During the last week some of the mice were also injected with LIF, 2 mug/kg s.c. every other day for a total of four injections. Development of neuropathy was evaluated with changes in tail flick latency and sensory nerve conduction velocity (NCV). At the end of the treatment period dorsal root ganglia (DRG) were microscopically examined. Some of the DRGs were explanted into extracellular matrix, covered with culture medium and incubated for 3 days. During and at the end of the incubation, cellular migration and axonal outgrowth from the DRGs were quantified. LIF proved effective in reversing the increase in tail flick latency (p < 0.05) and improving the reduction in NCV induced by CDDP. CDDP led to smaller nuclear and somatic size in neurons, while with LIF, the latter was restored to control values (p<0.01). No apoptotic nucleus was observed among DRG neurons while very few and moderate numbers detected among satellite and Schwann cells, respectively. With LIF, none of the cells had apoptosis. CDDP caused a decrease in the number of migrating cells and in the length of outgrowing axons while LIF treatment restored both capacities (p < 0.05) In conclusion, in CDDP-induced neuropathy, LIF was found to be effective in correcting some functional and morphological deteriorations related with major involvement of Schwann cells. (C) 2004 Elsevier Ltd. All rights reserved.
Hepatoprotective Effect of Foeniculum Vulgare Essential Oil
(Elsevier Science Bv, 2003) Özbek, H; Ugras, S; Dülger, H; Bayram, I; Tuncer, I; Öztürk, G; Öztürk, A
Hepatoprotective activity of Foeniculum vulgare (fennel) essential oil (FEO) was studied using carbon tetrachloride (CCl4) induced liver injury model in rats. The hepatotoxicity produced by acute CCl4 administration was found to be inhibited by FEO with evidence of decreased levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin. The results of this study indicate that FEO has a potent hepatoprotective action against CCl4-induced hepatic damage in rats. (C) 2003 Elsevier Science B.V. All rights reserved.
Multidimensional Long-Term Time-Lapse Microscopy of in Vitro Peripheral Nerve Regeneration
(Wiley, 2004) Öztürk, G; Erdogan, E
In order to test the effectiveness of a new advanced time-lapse microscopy imaging and image processing and analysis system, and to do quantitative and qualitative temporal analyses of in vitro peripheral nerve regeneration, long-term time-lapse imaging of cultures of mouse dorsal root ganglia (DRGs) was performed. DRGs were placed in a Petri dish, covered with collagen gel, their attached peripheral nerves were cut in the middle, creating a gap, and the dish was filled with culture medium. Six preparations were kept on the time-lapse imaging system, which provides a suitable incubation environment and enables to capture images from multiple coordinates at x,y,z axes at desired time intervals for 13 days. In general, the time-lapse imaging system proved quite stable and efficient, although some improvements are certainly required. Two main components of peripheral nerve regeneration, outgrowth of axons and activities of resident cells, were examined. Axons started to grow during the first hour of incubation with a 16.5 mum/h rate and showed the slowest rates (0.7 mum/h) on days 8 and 9, after which they resumed higher speeds again. The first cell came out of the proximal end of the cut nerve on the second day and it was a Schwann cell (SC), which was the prominent cell type in the preparations throughout the experiment. SCs were higher in number (83.15% of all cells) but slower in migration (3.4 vs. 7.3 mum/h, P < 0.001) than other cells. Other observed characteristics of axonal outgrowth and cellular activity and interactions between axons and the cells are discussed. (C) 2004 Wiley-Liss, Inc.
Regulation of Calcitonin Gene-Related Peptide Expression in Vitro
(Elsevier, 2002) Öztürk, G
Calcitonin-gene related peptide is among a group of peptides whose expressions are down-regulated following peripheral nerve damage. It is known that this is probably due to deprivation of some target-derived neurotrophic factors, mainly of nerve growth factor though positive effect of other factors, for example that of leukemia inhibitory factor on galanin has also been demonstrated. In this study, the effects of leukemia inhibitory factor and nerve growth factor on calcitonin gene related peptide expression in cultured dorsal root ganglion explants and in their outgrowing axons were examined. Lumbar dorsal root ganglia with short pieces of peripheral nerves were removed from adult mice and explanted into collagen gels. They were covered with RPMI 1640 culture medium and left in an incubator for 2 days after which they were fixed. These whole mount preparations with outgrowing axons were stained with an antibody against calcitonin gene related peptide. Following microscopic examination and imaging, sections were cut from the cultured ganglia as well as from some freshly taken normal ones and they were also stained to determine calcitonin gene related peptide immunoreactivity in the primary sensory neurons. The results demonstrated that besides the positive effect of nerve growth factor on the expression of this peptide in outgrowing axons, leukemia inhibitory factor also supported the expression of calcitonin gene related peptide in the primary sensory neurons of adult mouse lumbar dorsal root ganglia and in their outgrowing axons in vitro. When the time course of changes in calcitonin gene related peptide expression in dorsal root ganglia and the up-regulation of leukemia inhibitory factor at the site of a peripheral nerve injury in vivo are considered together, this novel finding may lead to new explanations for the changes in neuropeptide expression following axotomy. (C) 2002 Elsevier Science B.V. All rights reserved.