Person: GÜLHAN, REZZAN
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GÜLHAN
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REZZAN
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Publication Open Access COLCHICINE USE DURING PREGNANCY: CASE REPORTS(BMJ PUBLISHING GROUP, 2019-06) KARAALP, ATİLA; Duman, Nesrin Caglayan; Karabacak, Murat; Oglu, Medine Gulcebi Idriz; Inanc, Nevsun; Asik, Zehra Nur Turgan; Atagunduz, Pamir; Ozkula, Songul; Gulhan, Rezzan; Goren, Zafer; Onat, Filiz; Direskeneli, Haner; Karaalp, AtilaPublication Metadata only Plasma lamotrigine levels of patients with polymorphic UGT1A4 enzymes(2010-06-27) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; GÖREN, MEHMET ZAFER; GÜLHAN, REZZAN; ONAT, FİLİZ; GÜLÇEBİ İDRİZ OĞLU M., ÖZKAYNAKÇI A., GÖREN M. Z. , ÖZKARA Ç., GÜLHAN R., ONAT F.Publication Metadata only The relationship between UGT1A4 polymorphism and serum concentration of lamotrigine in patients with epilepsy(ELSEVIER, 2011) ONAT, FİLİZ; Gulcebi, Medine Idrizoglu; Ozkaynakci, Aydan; Goren, Mehmet Zafer; Aker, Rezzan Gulhan; Ozkara, Cigdem; Onat, Filiz YilmazLamotrigine (LTG) which has a widespread use in epilepsy treatment as an antiepileptic agent is metabolized by UDP-glucuronosyl transferase (UGT) enzymes. In this study, single nucleotide polymorphisms, P24T and L48V, of the UGT1A4 enzyme have been investigated in a Turkish population of patients with epilepsy (n=131) by comparing serum levels of LTG of wild type and polymorphic subjects. High performance liquid chromatography (HPLC) was used to measure serum concentrations of LTG. The P24T and L48V polymorphisms of the UGT1A4 enzyme were analyzed with a matrix assisted laser desorption-time of flight (MALDI-TOF) mass spectrometry method. The frequencies of the heterozygous alleles for L48V or P24T polymorphisms were 22.4% and 3.8%, respectively. L48V polymorphism was found to decrease the serum concentration of LTG in patients on monotherapy or polytherapy. The LTG levels of non smoking monotherapy patients were 52% lower for the L48V polymorphism than for wild type alleles. Also the LTG levels were significantly lower for non smoking or smoking polymorphic alleles than for normal. The high frequency of the L48V polymorphism detected in the Turkish population indicates that LTG dose adjustments in patients with the UGT1A4 L48V polymorphic enzyme should be taken into account. (c) 2011 Elsevier B.V. All rights reserved.Publication Metadata only p353 Evalution of antiepileptic drug use in the pregnant patients with epilepsy in a university hospital in Istanbul(2014-07-03) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; GÜLHAN, REZZAN; KARAALP, ATİLA; GÖREN, MEHMET ZAFER; ONAT, FİLİZ; GÜLÇEBİ İDRİZ OĞLU M., Küçükibrahimoğlu E., JAFAROVA DEMİRKAPU M., GÜLHAN R., KARAALP A., GÖREN M. Z., ONAT F.Publication Metadata only Changes in intracellular protein expression in cortex., thalamus and hippocampus in a genetic rat model of absence epilepsy(PERGAMON-ELSEVIER SCIENCE LTD, 2011) OGAN, AYŞE; Danis, Ozkan; Demir, Serap; Gunel, Aslihan; Aker, Rezzan Gulhan; Gulcebi, Medine; Onat, Filiz; Ogan, AyseEpilepsy is a chronic disorder characterized by repeated seizures resulting from abnormal activation of neurons in the brain. Although mutations in genes related to Na+, K+, Ca2+ channels have been defined, few studies show intracellular protein changes. We have used proteomics to investigate the expression of soluble proteins in a genetic rat model of absence epilepsy Genetic Absence Epilepsy Rats from Strasbourg (GAERS). The advantage of this technique is its high throughput quantitative and qualitative detection of all proteins with their post-translational modifications at a given time. The parietal cortex and thalamus, which are the regions responsible for the generation of absence seizures, and the hippocampus, which is not involved in this activity, were dissected from GAERS and from non-epileptic control rat brains. Proteins from each tissue sample were isolated and separated by two-dimensional gel electrophoresis. Spots that showed significantly different levels of expression between controls and GAERS were identified by nano LC-ESI-MS/MS. Identified proteins were: ATP synthase subunit delta and the 14-3-3 zeta isoform in parietal cortex; myelin basic protein and macrophage migration inhibitory factor in thalamus; and macrophage migration inhibitory factor and 0-beta 2 globulin in hippocampus. All protein expressions were up-regulated in GAERS except 0-beta globulin. These soluble proteins are related to energy generation, signal transduction, inflammatory processes and membrane conductance. These results indicate that not only membrane proteins but also cytoplasmic proteins may take place in the pathophysiology and can be therapeutic targets in absence epilepsy. (C) 2011 Elsevier Inc. All rights reserved.Publication Metadata only Perirhinal cortical kindling in rats with genetic absence epilepsy(ELSEVIER IRELAND LTD, 2010) ONAT, FİLİZ; Akman, Ozlem; Karson, Ayse; Aker, Rezzan Gulhan; Ates, Nurbay; Onat, Filiz YilmazTwo genetic models of absence epilepsy, GAERS and WAG/Rij rat strains, are resistant to progression of partial seizures induced by amygdaloid or hippocampal kindling. Perirhinal cortex is one of the crucial areas for the secondary generalization of partial seizures. Therefore we focused on perirhinal cortical kindling in both epileptic rat strains and examined whether the resistance to limbic epilepsy is restricted to the amygdala and hippocampus or whether it can also occur with perirhinal cortical kindling. The mean afterdischarge (AD) thresholds were significantly higher in WAG/Rij and GAERS compared to the Wistar rats. Analysis of the rate of perirhinal cortical kindling for the 3 strains indicated highly significant differences. The mean number of stimulations for the development of the first stage 2, 3, 4 or 5 seizures was significantly higher in WAG/Rij and GAERS groups than in Wistar rats. Further, the cumulative total duration and number of SWDs increased during the first epoch of the post-stimulation period at the first stage 2 and 4/5 seizures in the WAG/Rij and GAERS rats compared to the pre-stimulation period. The higher AD threshold and delays to all stages of kindling in WAG/Rij and GAERS indicate that the perirhinal cortex is a part of the circuits involved in the kindling resistance in genetic models of absence epilepsy. (C) 2010 Elsevier Ireland Ltd. All rights reserved.Publication Metadata only Anticonvulsant activity of 3,5-dimethylpyrazole derivatives in animal models(SPRINGER BIRKHAUSER, 2011) KAYMAKÇIOĞLU, BEDİA; Kocyigit-Kaymakcioglu, Bedia; Aker, Rezzan Gulhan; Tezcan, Kutluhan; Sakalli, Eren; Ketenci, Sema; Oruc-Emre, Emine Elcin; Akin, Demet; Gurbanova, Ayten; Terzioglu, Berna; Onat, Filiz; Rollas, SevimA series of 3,5-dimethylpyrazole derivatives, structurally related to the previously described potent ameltolide analogues, were synthesized and evaluated for their anticonvulsant activity. Ten compounds were prepared by reacting the 4-amino-3,5-dimethylpyrazole with appropriate substituted carboxylic acids, benzoyl chlorides and benzaldehydes to obtain amide and imine derivatives. Initial anticonvulsant screening was performed using intraperitoneal pentylenetetrazole (PTZ) and maximal electroshock (MES) induced seizure tests in mice. Among the 10 tested compounds, N-[1-(4-methoxybenzoyl)-3,5-dimethylpyrazole-4-yl]-4-methoxybenzamide 2 and N-[1-(2,6-dichlorobenzoyl)-3,5-dimethylpyrazole-4-yl]-2,6-dichlorobenzamide 3 decreased seizure severity and the mortality rate in the PTZ test. Hence, compound 3 was tested in an animal model of absence epilepsy, Genetic Absence Epileptic Rats from Strasbourg (GAERS). There were no significant changes in the duration or number of spike-and-wave discharges in this model.Publication Metadata only Ultrastructural GABA immunocytochemistry in the mossy fiber terminals of Wistar and genetic absence epileptic rats receiving amygdaloid kindling stimulations(ELSEVIER, 2011) AKAKIN, DİLEK; Akakin, Dilek; Sirvanci, Serap; Gurbanova, Ayten; Aker, Rezzan; Onat, Filiz; San, TangulThe existence of absence epilepsy and temporal lobe epilepsy in the same patient is not common in clinical practice. The reason why both types of seizures are rarely seen in the same patient is not well understood. Therefore, we aimed to investigate kindling in a well known model of human absence epilepsy, genetic absence epilepsy rats from Strasbourg (GAERS). In the present study, we analyzed whether the GABA content of GAERS that received kindling stimulations was altered in the hippocampal mossy fiber terminals compared to non-epileptic control (NEC) Wistar rats. For this purpose, we used an immunocytochemical technique at the ultrastructural level. Ultrathin sections were immunolabeled with anti-GABA antibody and transmission electron microscopy was used for the ultrastructural examination. The number of gold particles per nerve terminal was counted and the area of the nerve terminal was determined using NIH image analysis program. The GABA density was found to be higher in sham-operated GAERS than sham-operated Wistar rats. The density was increased in kindling Wistar group compared to sham-operated Wistar and kindling GAERS groups. No statistical difference was observed between sham-operated GAERS and kindling GAERS groups. The increase in GABA levels in stimulated Wistar rats may be a result of a protective mechanism. Furthermore, there may be strain differences between Wistar rats and GAERS and our findings addressing different epileptogenesis mechanisms in these strains might be a basis for future experimental studies. (C) 2010 Elsevier B.V. All rights reserved.Publication Metadata only Localized cortical injections of ethosuximide suppress spike-and-wave activity and reduce the resistance to kindling in genetic absence epilepsy rats (GAERS)(ELSEVIER, 2010) ONAT, FİLİZ; Aker, Rezzan Guelhan; Tezcan, Kutluhan; Carcak, Nihan; Sakalli, Eren; Akin, Demet; Onat, Filiz YilmazModels of genetic absence epilepsy are resistant to secondary generalization of focal limbic seizures. This correlates with the postnatal development of spike-and-wave discharges (SWDs), a hallmark of absence seizures arising from a cortical focus in the perioral region of somatosensory cortex. Ethosuximide injected at this site suppresses SWDs. The effect of this suppression on kindling in Genetic Absence Epilepsy Rats from Strasbourg (GAERS), has been compared for postnatal 30 day (PN30) rats having immature SWDs and adult (>4 months) rats having mature SWDs. Non-epileptic Wistar and GAERS rats were implanted with a basolateral amygdaloid stimulation electrode, bilateral injection cannulas into the cortical perioral focus, and cortical recording electrodes. Following recovery cortical injections of ethosuximide or saline were made and after 30 min rats were given 36 stimulations or until Racine's stage 5 seizures were produced. All Wistar rats (PN30 and adult) treated with saline or ethosuximide reached stage 5. Of GAERS given saline, 33% (PN30) and 43% (adults) were resistant to kindling; after ethosuximide pups behaved like Wistars, but adults showed a delay in kindling relative to Wistars. These findings imply that mechanisms underlying kindling resistance are related but not limited to SWD activity in animals with genetic absence epilepsy. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only p41 Life threatening drug-drug interactions in patients in medical intensive care unit of a university hospital(2014-05-10) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; GÜLHAN, REZZAN; ONAT, FİLİZ; GÖREN, MEHMET ZAFER; GÜLÇEBİ İDRİZ OĞLU M., KARAALP A., Küçükibrahimoğlu E., JAFAROVA DEMİRKAPU M., GÜLHAN R., ONAT F., GÖREN M. Z.