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    Basilar artery angulation and vertigo due to the hemodynamic effect of dominant vertebral artery
    (Churchill Livingstone, 2008) Cosar, Murat; Yaman, Mehmet; Eser, Olcay; Songur, Ahmet; Ozen, Oguz A.
    Vertebral arteries form the basilar artery at the pontobulbar junction. The vertebral artery may have dominancy in one of them. The branches of basilar arteries supply blood for the vestibular nuclei and its connections. Vertigo is seen generally in the upper middle aged patients. Vertigo can be observed in dolichoectasia of basilar artery such as angulation and elongation, because of the diminished blood supply and changed hemodynamic factors of vestibular nuclei and its connections. We hypothesized that angulation or elongation of basilar artery can be estimated according to the unilateral vertebral artery dominant hypertensive patients. The basilar artery can angulate from the dominant side of vertebral artery to the recessive side. These angulation and elongation can effect the hemodynamic factors in absence of growing collateral arteries. So, the vertigo attacks may occur in these patients. (C) 2007 Elsevier Ltd. All rights reserved.
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    Determination of Quercetin in Medicinal Plants Such as Rose Hip (Rosa canina), Bettle (Urtica dioica), Terebinth (Terebinthina chica) and Purslane (Portulace oleracea) using HPLC-MS Method
    (Asian Journal Of Chemistry, 2012) Ozcan, Cemile; Dilgin, Yusuf; Yaman, Mehmet
    A simple and rapid high performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for the determination of quercetin in four plants and fruits samples which are rose hip (Rosa canina), nettle (Urtica dioica), terebinth (Terebinthina chica) and purslane (Portulace oleracea). For this purpose, flow rate of mobile phase, fragmentor potential, injection volume and column temperature were optimized as 0.6 mL min(-1), 140 V, 5 mu L and 30 degrees C, respectively. While the average recoveries were found at least 90 %, limit of detection and limit of quantification were found to be 0.1 and 0.4 mg L-1, respectively. The relative standard deviation for retention time and peak area of 25 mg L-1 quercetin was found to be 2.4 % and 3.5 %, respectively. The optimized method was successfully applied determination of quercetin in the plant and fruits samples after their extraction with a mixture of HCl, methanol and ascorbic acid.
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    Determination of quercetin in medicinal plants such as rose hip (Rosa canina), bettle (Urticadioica), terebinth (Terebinthina chica) and purslane (Portulace oleracea) using HPLC-MS method
    (Chemical Publishing Co., 2012) Ozcan, Cemile; Dilgin, Yusuf; Yaman, Mehmet
    A simple and rapid high performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for the determination of quercetin in four plants and fruits samples which are rose hip (Rosa canina), nettle (Urtica dioica), terebinth (Terebinthina chica) and purslane (Portulace oleracea). For this purpose, flow rate of mobile phase, fragmentor potential, injection volume and column temperature were optimized as 0.6 mL min-1, 140 V, 5 ?L and 30 °C, respectively. While the average recoveries were found at least 90 %, limit of detection and limit of quantification were found to be 0.1 and 0.4 mg L-1, respectively. The relative standard deviation for retention time and peak area of 25 mg L-1 quercetin was found to be 2.4 % and 3.5 %, respectively. The optimized method was successfully applied to determination of quercetin in the plant and fruits samples after their extraction with a mixture of HCl, methanol and ascorbic acid.
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    Sensitive Amperometric Detection of Hydroxylamine at Electropolymerized Curcumin Film Coated Pencil Graphite Electrode
    (John Wiley and Sons Inc, 2023) Güneş, Mehmet; Sap, Ayşe; Karakaya, Serkan; Yaman, Mehmet; Dilgin, Yusuf
    In this study, a sensitive electrochemical method was developed for the determination of hydroxylamine (H-A) using a curcumin-modified pencil graphite electrode prepared with the electropolymerization of curcumin (PolyCurc-PGE). The PolyCurc-PGE showed a remarkable electrocatalytic response for H-A oxidation compared with bare PGE. Amperometric and cyclic voltammetric measurements were performed based on the electrocatalytic oxidation of H-A at PolyCurc-PGE. Some parameters, such as monomer concentration, pH, and cycle number during electropolymerization, were optimized to obtain the best electrochemical response of the modified electrode towards H-A. Results show that the PolyCurc-PGE gives a linear response towards H-A oxidation in the range from 0.50 mu M to 500 mu M (R-2=0.9984). In addition, the sensitivity and detection limit (LOD) of PolyCurc-PGE were found to be 5432 mu A mM(-1) cm(2) and 0.15 mu M H-A, respectively. The developed amperometric method was successfully applied to determine H-A in pharmaceutical and water samples, and acceptable results were obtained with high accuracy and precision.
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    The influence of dexmedetomidine on ischemic rat hippocampus
    (Elsevier, 2008) Eser, Olcay; Fidan, Huseyin; Sahin, Onder; Cosar, Murat; Yaman, Mehmet; Mollaoglu, Hakan; Songur, Ahmet
    In our study, we evaluated the neuroprotective effects of dexmedetomidine on oxidantantioxidant systems, pro -inflammatory cytokine TNF-a and number of apoptotic neurons on hippocampus and dentate gyrus after transient global cerebral I/R injury. Eighteen rats divided into 3 groups, equally. Group I rats were used as shams. For group II and III rats, they were prepared for transient global cerebral ischemia using a four-vessel- occlusion model. 5 mL/kg/h 0.9% sodium chloride was infused to the Group II and 3 Pg/kg/h/5 ml dexmedetomidine was infused to the Group III for 2 h after I/R injury. The levels of MDA and NO and activities of SOD and CAT were measured in the left hippocampus tissue. The levels of TNF-a concentration were measured in the plasma. The number of apoptotic neurons was counted by TUNNEL method in histological samples of right hippocampus tissue. MDA and NO levels increased in Group II compared with Group I rats (p=0.002, p=0.002, respectively). In group III, MDA and NO levels decreased as compared to Group 11 (p=0.015, p=0.002, respectively). SOD and CAT activities increased in Group III as compared to Group II rats (p = 0.002, p = 0.002, respectively). The decrease in TNF-a levels of group III was significant as compared to group II (p=0.016). The number of apoptotic neurons in group III was lower than Group II rats. Our study showed that dexinedetomidine has a neuroprotective effect on hippocampus and dentate gyrus of rats after transient global cerebral I/R injury. (c) 2008 Elsevier B.V. All rights reserved.
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    The protective effect of avocado soybean unsaponifilables on brain ischemia/reperfusion injury in rat prefrontal cortex
    (Taylor & Francis Ltd, 2011) Eser, Olcay; Songur, Ahmet; Yaman, Mehmet; Cosar, Murat; Fidan, Huseyin; Sahin, Onder; Mollaoglu, Hakan
    Object. We investigated the protective effects of avocado/soybean unsaponifiables (ASU) on the prefrontal cortex (PFC) after global brain ischemia/reperfusion (I/R) injury in rats. Methods. Rats were randomly divided into three experimental groups as follows: Group I was control rats, Group II was ischemia rats, Group III was Isch+ASU rats. Brain ischemia was produced via four-vessel occlusion model. These processes followed by reperfusion for 30 min for both II and III groups. Rats were sacrificed and their brains were removed immediately. Malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in left PFC, levels of TNF-alpha concentration were measured in the plasma. The number of apoptotic neurons was assayed in histological samples of the right PFC. Results. MDA and TNF-alpha levels as well as the number of apoptotic neurons were observed to have decreased significantly in Group III compared to Group II, while SOD activities have been found to have increased significantly in Group III in comparison to Group II, significantly. Conclusions. We think that ASU might have an antioxidant and neuroprotective effects in brain I/R injured rats.