Browsing by Author "Okur, H."

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Central Nervous System Involvement in a Case of Familial Hemophagocytic Lymphohistiocytosis With Perforin Mutation
(Medecine Et Hygiene, 2011) Akbayram, S.; Akgun, C.; Dogan, M.; Caksen, H.; Okur, H.; Oner, A. -F.
Central nervous system involvement in a case of familial hemophagocytic lymphohistiocytosis with perforin mutation: Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive lethal condition characterized by fever, cytopenia, hepatosplenomegaly and hemophagocytosis. The presence of central nervous system involvement has a profound impact on the prognosis, treatment, and clinical outcome of the disease. Therefore, the identification of the clinical manifestations of the disease and the characterization of the accompanying neurological symptoms are of prime importance for the rapid diagnosis and subsequent clinical management of the disease. Herein, we report a case of FHL with homozygosity for perforin gene mutation, who presented with central nervous system involvement in the absence of systemic findings.
Changes of Hemostatic Factors in Children With Acute Lymphoblastic Leukemia Receiving Combined Chemotherapy Including High Dose Methylprednisolone and L-Asparaginase
(Harwood Academic Publishers GmbH, 1999) Öner, A.F.; Gürgey, A.; Kirazli, S.; Okur, H.; Tunç, B.
In this study, protein C (PC), protein S (PS), heparin cofactor II (HCFII), prothrombin fragment 1 + 2 (PF 1,2), thrombin-antithrombin III complex (TAT), von Willebrand factor (vWF) and thrombomodulin (TM) were investigated in 19 patients with acute lymphoblastic leukemia, (ALL) receiving combined chemotherapy including L-asparaginase (L-ASP) and high dose methylprednisolone (HDMP). HDMP was administered in doses of 30 mg/kg/day for 7 days, and 20 mg/kg/day for another 7 days. In order to evaluate the effect of HDMP on the hemostatic system, the 8 patients studied here received HDMP (30 mg/kg/day) therapy for 4 days before the combined chemotherapy. These parameters were also studied in 12 healthy children as a control group. PC levels were normal in the patients while PS levels were decreased both before and after combined chemotherapies. Patients with ALL have laboratory signs of coagulation activation such as PF 1,2, TAT prior to initiation of chemotherapy. With combined chemotherapy, TAT levels were found to be normal while PF 1,2 were not. TM levels were found to be increased both before and after therapies whereas HCFII and vWF levels were not different from those of the control group. The short course of HDMP therapy did not prominently influence these hemostatic parameters. These results indicate that both the malignant process and the drugs used in combined chemotherapy cause a decrease in natural inhibitors and an increase in procoagulant activity and endothelial injury. These hemostatic changes may contribute to a thrombotic tendency in the patients with ALL.
Disease Causing Nature of Homozygous Missense, P.a523d, Alteration in the Perforin Gene
(2009) Oner, A.F.; Okur, H.; Balta, G.; Unal, S.; Deger, I.; Akarsu, N.; Gurgey, A.
Isoimperatorin-Mediated Anticancer Activity: Role of Mitochondrial Dysfunction in Hepg2 Cells
(University of Ankara, 2023) Ergüç, A.; Arzuk, E.; Albayrak, G.; Karakus, F.; Okur, H.; Baykan, S.
Objective: The first goal of the present study is to investigate the role of mitochondria due to the Crabtree effect in HepG2 cells exposed to ISO in either glucose-or galactose-conditioned media. The second aim is to predict the interactions between electron transport chain (ETC) complexes and ISO, which might be the possible reason for mitochondrial dysfunction. Material and Method: Cell viability and membrane damage for HepG2 cells exposed to ISO (12.5, 25, 50, 100, and 250 uM) were assessed by MTT and LDH leakage assays in either glucose-or galactose-conditioned media. The affinity of ISO to ETC complexes was also determined by a molecular docking study. Result and Discussion: MTT assay showed that 250 uM ISO leads to cytotoxic activity in glucose-conditioned media, while 25 uM and higher concentrations of ISO decrease cell viability in galactose-conditioned media. A membrane damage assay conducted in a glucose-conditioned media assay revealed that 250 uM ISO disrupts the cell membrane. 100 and 250 uM ISO increased membrane damage in galactose-conditioned media. According to docking simulations, binding affinities of ISO to ETC complexes are in descending order: Complex IV Complex I Complex III Complex II. Inhibition of complex IV by ISO inhibits the transfer of electrons from cytochrome c to oxygen, and the proton gradient collapses. The present study proposed that ISO leads to mitochondrial dysfunction via inhibition of the ETC. © 2023 University of Ankara. All rights reserved.