Person: GÖREN, MEHMET ZAFER
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GÖREN
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MEHMET ZAFER
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Publication Open Access The effects of partial bilateral lesioning of substantia nigra in a genetic absence epilepsy rat model(2002-04-01) GÜLHAN, REZZAN; ONAT, FİLİZ; GÖREN, MEHMET ZAFER; GÖREN M. Z., GÜLHAN R., ONAT F., Ergün A.Objective: \"Genetic Absence Epilepsy Rats from Strasbourg\" (GAERS), an inbred Wistar strain, serve as an experimental venue. These rats generate spontaneous spike-and-wave discharges (SWD) and have increased γ-aminobutyric acid (GABA) levels in the ventrolateral thalamus (VLT). Recently, substantia nigra pars reticulata (SNpr) was reported to act as an endogeneous inhibitory mechanism in the generation, onset and maintenance of various types of seizures. The presence of tonic control exerted by SNpr in absence seizures should also be tested in GAERS. Methods: In this current study, GABA and L-glutamic acid release in VLT of GAERS with partial bilateral electrolytic lesions of SNpr was evaluated by using microdialysis technique with fluorescent detection. Results: GABA levels in VLT were 0.12±0.04 μM and 0.24±0.08 μM in sham-lesioned and SNpr-lesioned GAERS, respectively. L-glutamic acid level was found to be 0.41 5±0.150 μM in sham-lesioned group and 0.324±0.094 μM in SNpr-lesioned GAERS. Statistical analysis revealed no significant difference between sham-lesioned and SNpr-lesioned rats. The number and the duration of SWD were also similar in two groups. Conclusion: These findings show that SNpr does not exert a tonic control in GAERS and we assume that intact SNpr acts as a site that may exert an inhibition on target structures when activated in GAERS.Publication 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 Open Access Plasma concentration-time profile of a single dose of enteric-coated omeprazole in male and female healthy volunteers(2000-01-01) GÖREN, MEHMET ZAFER; AKIN, ŞEHNAZ; GÜLHAN, REZZAN; ONAT, FİLİZ; Iskender E., ASLAN N., GÖREN M. Z., Tellioglu T., Akin S., Erin N., GÜLHAN R., ONAT F., Berkman K., Oktay S.O b je c tiv e : T h e b io a vaila b ility of a single dose (20 m g) o f tw o e n te ric -c o a te d o m e p ra z o le fo rm u la tio n s, m arketed in T urkey, given 10-15 m in b e fo re b reakfast, w as studied in 12 healthy vo lu n te e rs (6 m ales and 6 fem ales) in a d o u b le blind, cro s s o v e r design. M e th o d s : B lood sam ples w ere collected prior to and at 10 tim e points w ithin 12 hrs. after dosing. P la s m a o m e p ra z o le c o n c e n tra tio n s w e re m easured by H P LC te ch n iq u e in our laboratory. R e s u lts a n d C o n c lu s io n s : T he tw o products w ere found to be b io e q u iva le n t in term s of extent of a b s o rp tio n (th e a re a u n d e r the p la s m a c o n c e n tra tio n -tim e cu rve s). M u ltip e a k p la sm a co n ce n tra tio n pro file s w e re seen in m ost of the su b je cts w ith both products. T im e to the e a rlie r peaks w as 1-2 hrs. and those peaks w ere low er in a m p litu d e th a n th e p e a ks re a ch e d a p p ro x im a te ly 4 .5 hrs. a fte r the a p p lica tio n . In te re stin g ly, the m u ltip e a k profile w as m ore fre q u e n t and the e a rlie r peaks w ere sig nificantly higher in fe m a le su b je cts than in m ales. The reason fo r th is g e n d e r d iffe re n ce in m ultipeak p la s m a c o n c e n tra tio n - tim e p ro file of oral o m e p ra zo le needs fu rth e r investigation.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 The effect of telmisartan, an angiotensin receptor blocker, on alcohol consumption and alcohol-induced dopamine release in the nucleus accumbens(ELSEVIER SCIENCE INC, 2020) YANANLI, HASAN RACİ; Tezcan, Kutluhan; Yananli, Hasan Raci; Demirkapu, Mahluga Jafarova; Goren, M. Zafer; Sakalli, H. Eren; Colombo, Giancarlo; Gulhan, RezzanAlcohol use disorder remains a major health problem. The mesocorticolimbic dopaminergic system, including the nucleus accumbens region and multiple neural circuits, is involved in its complex underlying mechanism. For instance, alcohol intake stimulates the central and peripheral renin-angiotensin system and increases angiotensin II levels, which predominantly affect angiotensin 1 receptors both in the periphery and in the brain. In this study, we aimed to investigate the effects of the intracerebroventricularly-administered angiotensin 1 receptor blocker telmisartan on the alcohol consumption of male Sardinian alcohol-preferring (sP) rats and on the alcohol-induced dopamine levels in the nucleus accumbens region in Wistar rats. Acute intracerebroventricular administration of telmisartan (100 nM) reduced the alcohol intake for 24 hours without affecting food and water consumption in sP rats. Acute intracerebroventricular injection of the opioid receptor antagonist naloxone (75 nM), tested as a reference compound, also reduced the alcohol consumption in sP rats; however, naloxone's effect lasted only for 30 minutes. In microdialysis experiments, telmisartan administered intracerebroventricularly did not change dopamine levels in the nucleus accumbens that had been induced by acute intraperitoneal alcohol administration in Wistar rats. According to these results, further studies are needed to elucidate the role of the renin-angiotensin system on alcohol use disorder pathophysiology. (c) 2021 Elsevier Inc. 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.Publication Metadata only Potential drug interactions with antiepileptics in the intensive care unit patients of a university hospital(2015-02-01) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; GÜLHAN, REZZAN; KARAALP, ATİLA; GÖREN, MEHMET ZAFER; ONAT, FİLİZ; GÜLÇEBİ İDRİZ OĞLU M., Duman N., GÜLHAN R., KARAALP A., GÖREN M. Z. , ONAT F.