Researcher:
Sağlam, Gökay

Profile Picture
ORCID

Job Title

Undergraduate Student

First Name

Gökay

Last Name

Sağlam

Name

Name Variants

Sağlam, Gökay

Email Address

Birth Date

Filters

2017 - 20182

Advanced Search

Filter by

Settings

Researcher Of Publications: search.filters.isAuthorOfPublication.c1a4c7d8-10ae-408b-8d65-950e72d6b0e8

Search Results

Now showing 1 - 2 of 2
  • Placeholder
    PublicationMetadata only
    Afferent projections of the subthalamic nucleus in the rat: mphasis on bilateral and interhemispheric connections
    (Nencki Inst Experimental Biology, 2018) Çavdar, Safiye; Özgür, Merve; Çakmak, Yusuf Özgür; Kuvvet, Yasemin; Kunt, Kezban Sıla; Sağlam, Gökay; Faculty Member; PhD Student; Faculty Member; PhD Student; Undergraduate Student; Undergraduate Student; School of Medicine; Graduate School of Health Sciences; School of Medicine; Graduate School of Health Sciences; School of Medicine; School of Medicine; Koç University Hospital; 1995; 197462; N/A; N/A; N/A; N/A
    The subthalamic nucleus (STN) is important for normal movement as well as in movement disorders. The STN is a target nuclei in patients with advanced Parkinson's disease (PD). Deep brain stimulation (DBS) is a standard surgical treatment for PD. Although DBS results in a significant reduction in motor disability, several negative side effects have been reported. Thus, to understand the side effects of DBS the connection of the STN should be well known. Therefore, the present study aims to re-examine the STN with an emphasis on poorly- or un-documented connections. Furthermore, the bilateral and interhemispheric connections of the STN are evaluated. Fifteen male albino rats received injections of Fluoro-Gold retrograde and biotinylated dextran amine anterograde tracers into the STN. Following a 7-10 day survival period, the animals were processed according to the relevant protocol for each tracer. The present study demonstrates ipsilateral connections of the STN with cortical regions (i.e., infralimbic, cingulate, frontal, piriform, primary motor, primary sensory, insular and retrosplenial cortices), the endopiriform nucleus, basal ganglia related structures (i.e., caudate putamen, globus pallidus, ventral pallidum, nucleus accumbens, claustrum and substantia innominata) and the deep cerebellar nuclei (i.e., lateral, anterior interposed). Bilateral connections of the STN were observed with limbic (amygdala, bed nucleus of stria terminalis), hypothalamic (ventromedial, posterior, anterior, lateral and mammillary) thalamic (thalamic reticular nucleus), epithalamic (habenular nucleus), and brainstem structures (superior colliculus, substantia nigra, spinal nucleus of the trigeminal nerve, red nucleus, dorsal raphe nucleus, pedunculopontine tegmental nuclei). Interhemispheric connections between left and right STN were also observed. The present study fills important gaps in connectivity of the STN. In particular, we report STN connectivity with cortical areas (i.e., piriform, endopiriform and insular), claustrum, hypothalamic, thalamic reticular, cerebellar, habenular, trigeminal, red, cuneate and gracile nuclei and substantia innominate. These connections, which have not been previously described or poorly described, provide new routes that can alter the conceptual architecture of the basal ganglia circuitry and may modify our view of the functional identity of the STN.
  • Placeholder
    PublicationMetadata only
    Dependence of erythrocyte deformability on mechanical stress and oxygenation
    (Federation amer Soc Exp Biol, 2017) N/A; N/A; N/A; Department of Physics; N/A; Yalçın, Özlem; Uğurel, Elif; Sağlam, Gökay; Erten, Ahmet Can; Aksu, Ali Cenk; Faculty Member; Researcher; Undergraduate Student; Teaching Faculty; PhD Student; Department of Physics; School of Medicine; School of Medicine; School of Medicine; College of Engineering; Graduate School of Health Sciences; 218440; N/A; N/A; N/A; N/A
    Mechanical properties of erythrocytes are known to be affected by their oxygenation status. Several studies suggested that cytoskeletal rearrangements are carried out in an oxygen dependent manner. The structure of the cytoskeleton determines the mechanical properties of erythrocyte membrane. However, oxygen-dependent mechanical characteristics of erythrocyte are poorly studied whether oxygenated state could alter erythrocyte deformability. In this study, we investigated shear stress induced improvements in erythrocyte deformability through their oxygenation status. Venous blood was collected from male, healthy volunteers (n=10) between 25–50 ages. An informed written consent was obtained from each subject participated in the study according to Declaration of Helsinki. The hematocrit of blood samples adjusted to 0.4 l/l with autologous plasma. Whole blood samples were diluted with polyvinylpyrrolidone (PVP) solution (Mechatronics, Hoorn, Netherlands) with a dilution ratio of 1/200. Blood samples were equilibrated with either ambient air or nitrogen gas for at least 10 minutes at room temperature. Erythrocyte deformability was measured by a laser-assisted optical rotational cell analyzer (LORRCA MaxSis, Mechatronics, Netherlands) applying shear stresses (SS) ranging between 0.3 to 50 Pa. Then, a constant SS of 5, 10 and 20 Pa were applied continuously for 300 seconds and erythrocyte deformability was measured immediately afterwards. Maximal erythrocyte elongation index (EImax) and the SS required for one-half of this maximal deformation (SS1/2) were calculated by using the linear Lineweaver-Burke (LB) model. Deoxygenation of blood samples significantly decreased SS1/2 values both before and after SS applications (p < 0.001). EImax was significantly increased in deoxygenated blood before applying 5 Pa SS (p < 0.05). However, there were no significant differences after continuous SS in oxygenated and deoxygenated blood. Deoxygenation significantly decreased SS1/2/EImax values both before and after SS applications (p < 0.01). SS1/2/EImax values in both oxygenated and deoxygenated blood were significantly decreased after 5 and 10 Pa continuous SS applications although they were not significantly decreased after applying 20 Pa SS. Our study showed for the first time that erythrocyte deformability is improved in deoxygenated conditions in contrast to results presented in previous studies. This deformability improvement may control blood flow and consequently erythrocyte distribution within hypoxic tissues. Our study also demonstrated the relationship of oxygenation-deoxygenation shifts and magnitude of shear stress on erythrocyte deformability.