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GÜLHAN, REZZAN

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Author: ONAT, FİLİZ × Subject: Fundamental Medical Sciences ×

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Now showing 1 - 3 of 3
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    PublicationOpen 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.
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    PublicationOpen Access
    Alterations in the kinetic activity of aromatlc-L-amino acid decarboxylase and preliminary 2-DE investigation of the brains in a 6-OHDA induced Parkinson's disease rat model
    (2003-07-01) OGAN, AYŞE; ONAT, FİLİZ; GÜLHAN, REZZAN; Günel A., OGAN A., ONAT F., GÜLHAN R.
    Objective: The aim of this study was to isolate and purify the aromatic-L-amino acid decarboxylase (AADC,EC 4.1.1.28) enzyme rats from Parkinson\"s Disease (PD) induced and the healthy control group rat brains and compare the alterations in the kinetic activities of the isolated enzyme. The protein spots displaying on the 2-DE patterns of the diseased and the healthy control group crude rat brain homogenates were evaluated. Medhods: In this study, the Parkinson\"s Disease model was induced by injecting 6-hydroxydopamine into the brains of the rats. The PD model formation was successful in two rats out of three. Results: The AADC decarboxylase was isolated and partially purified by DEAE-Sephacel ion exchange chromatography from the brains of PD induced and healthy control animals to compare the kinetic activity of the enzyme. The kinetic activity of the enzyme was reduced 70% in the PD group compared to controls. In order to determine and correlate the alterations with PD, and the distribution of the proteins displayed by the crude brain homogenates of the diseased and the healthy control group both were investigated. Polyacrylamide gel electrophoresis (PAGE) of the crude brain homogenates under the native and denaturizing conditions displayed matching bands for both of the groups, while two dimensional electrophoresis (2-DE) patterns of the crude brain homogenates of the diseased and the control group displayed considerable differences. Conclusion: The results of this study confirm the power of 2-DE-PAGE technique of the proteome analysis. Currently only the proteome analysis enables the identification of disease correlated proteins.
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    PublicationOpen 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.