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Dive into the research topics where Okan Özcan is active.

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Featured researches published by Okan Özcan.


Epilepsia | 1995

Plasma Trace Element, Plasma Glutathione Peroxidase, and Superoxide Dismutase Levels in Epileptic Children Receiving Antiepileptic Drug Therapy

A.Emin Kürekçi; Faruk Alpay; Sakir Tanindi; Erdal Gökçay; Okan Özcan; Ridvan Akin; Askin Isimer; Ahmet Sayal

Summary: Some antiepileptic drugs (AEDs) may altertrace element metabolism and free radical scavenging enzyme activities in humans and experimental animals. We investigated the effect of longterm AED therapy on copper (Cu), zinc (Zn), manganese (Mn), selenium (Se), magnesium (Mg), glutathione peroxidase (GSH‐PX), and superoxide dismutase (SOD) in the plasma in children with epilepsy. During treatment with valproate (VPA) or carbamazepine (CBZ) monotherapy plasma Cu, Zn, Mn, Se, and Mg concentrations of patients were not statistically different from those of control subjects. The level of seoxidation may be causally involved in some forms of epilepsies, and the decreased free radical scavenging enzyme activity is believed to cause the increased risk of anidiosyncratic drug reaction encountered in the manage‐ment of epilepsy. Because GSH‐PX and SOD are themost important members of antioxidant defense mechanisms, we quantitated the activities of these enzymes inplasma of children with epilepsy receiving VPA or CBZ. Only plasma GSH‐PX activities in VPA group werehigher than those of the control group, and the differencewas statistically significant.


Acta Paediatrica | 2000

High‐dose intravenous immunoglobulin therapy in neonatal immune haemolytic jaundice

Faruk Alpay; Serdar Umit Sarici; Okutan; G Erdem; Okan Özcan; Erdal Gökçay

A controlled study was conducted to assess the role of high‐dose i.v. immunoglobulin (HDIVIG) therapy in neonatal immune haemolytic jaundice. Patients with ABO and/or Rh incompatibilities proved by significant hyperbilirubinaemia (<204mmol 1−1), positive direct antiglobulin test and high reticulocyte count (>10%) were randomly assigned to receive either conventional phototherapy alone or phototherapy with high‐dose i.v. immunoglobulin (1 g kg−1, over 4h) as soon as the diagnosis was established. Exchange transfusions were performed if serum bilirubin concentrations exceeded 290 mmol 1−1 and increased by more than 17 mmol 1−1 per h despite both treatment manoeuvres. Eight of 58 patients in the HDIVIG group required exchange transfusions, whereas it became necessary in 22 of 58 patients in the control group (p < 0.001). The durations of phototherapy and hospitalization in terms of hours were significantly shorter in the HDIVIG group (p < 0.05). No side effects of HDIVIG therapy were observed. In conclusion, HDIVIG therapy in newborns with ABO or Rh haemolytic diseases reduces haemolysis, serum bilirubin levels and the need for blood exchange transfusion, a procedure which has potential complications and carries a risk of mortality.


Journal of Tropical Pediatrics | 2000

Double versus single phototherapy in term newborns with significant hyperbilirubinemia

Serdar Umit Sarici; Faruk Alpay; Bülent Ünay; Okan Özcan; Erdal Gökçay

The efficacy of double phototherapy, in the form of conventional phototherapy with special blue light plus fiberoptic phototherapy, was compared with conventional phototherapy consisting of special blue lamps alone in a relatively larger series of term newborns with significant hyperbilirubinemia. During the study period the sum of the average spectral irradiances in the double phototherapy group was significantly higher than that of the single phototherapy group (p < 0.05). Phototherapy was effective in decreasing bilirubin levels in both groups, but the response was greater in the double phototherapy group; the duration of exposure to phototherapy was significantly shorter (31.2 +/- 8.5 vs. 38.98 +/- 14.7 h, p < 0.05), and the overall bilirubin decline rate as mumol/l/h and per cent/h was significantly greater in the double phototherapy group (4.1 +/- 1.37 vs. 3.3 +/- 0.86 mumol/l/h, and 1.29 +/- 0.38 vs. 1.02 +/- 0.44 per cent/h, p < 0.05). In phototherapy treatment of term newborns with significant hyperbilirubinemia, double phototherapy provided more rapid and effective bilirubin reduction than conventional phototherapy alone due to higher spectral irradiance and larger body surface area exposed to phototherapy. The value of double phototherapy in the treatment of newborns with hemolytic hyperbilirubinemia remains to be determined.


European Journal of Pediatrics | 1998

Comparison of the efficacy and side-effects of ondansetron and metoclopramide-diphenhydramine administered to control nausea and vomiting in children treated with antineoplastic chemotherapy: a prospective randomized study

V. Köseogˇlu; Ahmet Emin Kürekçi; Ü. Sorici; A. Avni Atay; Okan Özcan

Abstract Nausea and vomiting following antineoplastic therapy in patients receiving chemotherapy remains a problem. To prevent nausea and vomiting due to antineoplastic therapy, many types of drugs have been used. Ondansetron and the combination metoclopramide-diphenhydramine have been widely used in children. In this prospective randomized study these drugs were compared both for their efficacy and side-effects in children treated with antineoplastic chemotherapy (with and without cisplatin) the number of chemotherapy courses being equal in both groups. Ondansetron gave complete anti-emetic cover in five of nine courses in patients treated with cisplatin. Metoclopramide-diphenhydramine gave complete anti-emetic cover in one out of nine courses, and 17 out of 23 courses in patients treated without cisplatin. Metoclopramide-diphenhydramine produced side effects in nine courses whereas ondansetron produced side-effects in three courses. Conclusion Ondansetron appeared to be superior to metoclopramide-diphenhydramine in the control of emesis induced by chemotherapy regimens containing cisplatin. The results of the present prospective randomized study indicate that ondansetron is a useful anti-emetic in the treatment of chemotherapy-induced emesis.


Thrombosis Research | 1995

The normalization period of platelet aggregation in newborns

Şakir Tanindi; A.Emin Kürekçi; Vedat Köseoǧlu; Metin Kurt; Okan Özcan

This study was performed to investigate the normalization period of the transient platelet dysfunction of newborns. A total of 43 healthy newborns of healthy mothers who had received no medication for at least 14 days prior to delivery were included in the study. Venous blood samples of 44 healthy volunteer adults were used as control. Platelet aggregation study was performed in whole blood by impedance aggregometry. Collagen or ADP was used as the aggregating agent. In the platelet aggregation studies using collagen, maximum aggregation values in the first three days of life were lower than those of adults (p < 0.001). These lower values were improved and reached adult values between the 5th and 9th day of life. Lower maximum aggregation values were observed in newborns in comparison with those of adults when ADP was used, but the difference was not significant except for 5 microM concentration of ADP. There was no significant difference between the aggregation time of the collagen and ADP groups (p > 0.05). In conclusion, the platelet responses to ADP and collagen were increased in newborns as the age progressed and reached normal levels between 5th and 9th day of life. If platelet dysfunction does exist after the 10th day of life, this finding may be due to either simple prolongation of the physiological phenomenon or platelet disorders.


Pediatric Hematology and Oncology | 2004

Complete platelet recovery after treatment of Helicobacter pylori infection in a child with chronic immune thrombocytopenic purpura: a case report.

A.Emin Kürekçi; A. Avni Atay; S. Umit Sarici; Okan Özcan

Helicobacter pylori gastritis has been associated with autoimmune disease, including immune thrombocytopenic purpura (ITP). The most recent reports also have supported this association in adults. ITP in children differs from that in adults in terms of clinical picture and mechanisms of thrombocytopenia. The authors report a case of a 12-year-old boy with chronic ITP, in whom they detected H. pylori infection and observed a complete platelet recovery after the eradication of H. pylori.


Brain & Development | 2009

The effects of biotin supplementation on serum and liver tissue biotinidase enzyme activity and alopecia in rats which were administrated to valproic acid

Mutluay Arslan; Sebahattin Vurucu; Necati Balamtekin; Bülent Ünay; Ridvan Akin; Ismail Kurt; Okan Özcan

Valproic acid (VPA) is a widely used and well-tolerable antiepileptic drug in epileptic patients. However, VPA has many side effects dose-dependent or non-dose-dependent. It is reported that VPA treatment may lead to biotin deficiency and low serum and liver tissue biotinidase enzyme activity (BEA). Major clinical manifestations in biotin deficiency are seborrheic dermatitis, dry skin, fine and brittle hair, and alopecia. We aimed to investigate the effects of biotin supplementation on serum and liver tissue BEA and alopecia during VPA therapy. Rats were randomly divided into 4 groups, each consisted of 15 rats (VPA-B1, VPA-B2, VPA, and control). Except the control group, all groups were administrated VPA dose of 600 mg/kg/d per oral (PO) for 60 days with 12h intervals two divided doses. VPA-B1 was administrated biotin dose of 6 mg/kg/d and VPA-B2 was administrated biotin dose of 0.6 mg/kg/d. In the third week of the study, we determined alopecia in the study groups. Alopecia was seen in the subjects of 13.3% of VPA-B1 (n=2), 13.3% of VPA-B2 (n=2), and 40% of VPA (n=6). But statistical significant effect on alopecia by biotin supplementation was not able to be determined between the study groups. In the control group, alopecia was not observed. The ratios of alopecia in the study groups were statistically higher than the control group (p=0.028). Itchiness was more obvious in the study groups compared with the control group. Serum biotin levels of the biotin supplemented groups (VPA-B1 and VPA-B2) were higher than the other groups (VPA and control group). Serum biotin levels of the VPA group were lower than the control group. There were significant decreases in the levels of serum and liver tissue BEA of the study groups compared with the control group. In conclusion we showed that VPA usage reduced the serum and liver tissue BEA and impaired the biotin utilization by affecting the liver. Partial biotinidase deficiency may lead to alopecia. It might be prevented by biotin supplementation in the patients receiving VPA therapy. We considered that further studies are necessary to find out the effective and safe biotin dose.


Thrombosis Research | 2000

Effect of iron therapy on the whole blood platelet aggregation in infants with iron deficiency anemia.

Ahmet Emin Kürekçi; A. Avni Atay; S. Umit Sarici; Cengiz Zeybek; Vedat Koseoglu; Okan Özcan

This study was performed to investigate the platelet aggregation alterations in whole blood samples of infants with iron deficiency anemia. Platelet aggregation induced by various concentrations of adenosine diphosphate (ADP) and collagen was studied with impedance aggregometry in 25 patients before and after oral iron therapy and in 12 children of the control group. The posttreatment mean maximum aggregation values were significantly higher (p<0.01) and the posttreatment mean aggregation times were significantly lower (p<0.01) in the study group at all concentrations of ADP and collagen. The aggregation time and maximum aggregation values revealed no significant difference except for the maximum aggregation value at 5 microM ADP (p<0.05) between the study group after therapy and the control group. The differences between the pretreatment and posttreatment mean platelet counts and mean platelet volume values in the study group were statistically significant (p<0.01), whereas those values in the study group after therapy and in the control group were not significantly different. We conclude that iron deficiency anemia in infants, even without clinically meaningful platelet abnormality, may cause dysfunction of the ex vivo whole blood platelet aggregation, and can be reversed by iron therapy. Further studies should be carried out at the enzymatic level to determine whether this platelet aggregation dysfunction in iron deficiency anemia is due to a deficiency in the activation of iron-containing enzymes.


Nephrology | 2005

Renal tubular function in children with beta-thalassemia minor.

Süleyman Kalman; A. Avni Atay; Onur Sakallioḡlu; Taner Özgürtaş; Faysal Gok; Ismail Kurt; A.Emin Kürekçi; Okan Özcan; Erdal Gökçay

Background:  β‐thalassemia minor is a common heterozygous haemoglobinopathy that is characterized by both microcytosis and hypochromia. It requires no treatment. It has been postulated that low‐grade haemolysis, tubular iron deposition and toxins derived from erythrocytes might cause renal tubular damage in adult patients with β‐thalassemia minor. Our aim was to investigate the renal tubular functions in children with β‐thalassemia minor and to determine its possible harmful effects.


American Journal of Perinatology | 2010

Neurodevelopmental status of preterm newborns at infancy, born at a tertiary care center in Turkey.

Mehmet Saldir; Serdar Umit Sarici; Emel Bakar; Okan Özcan

Our objective was to determine the incidence of early neonatal problems and the neurodevelopmental status and probable risk factors associated with neurodevelopmental abnormality in preterm infants of < or = 32 weeks of gestation. Preterm newborns of < or = 32 weeks of gestation followed at the neonatal intensive care unit of the Department of Pediatrics of Gülhane Military Medical Academy, Ankara, Turkey, were evaluated with a complete neurological examination and the Bayley Scales of Infant Development at a mean age of 25.85 + or - 11.79 months (range, 10 to 42 months). Multivariate logistic regression analyses were performed to determine the probable risk factors associated with neurodevelopmental abnormalities. Regarding the results of the neurological examination in a total of 169 preterms included in the study, 28 (16.6%) and 14 (8.3%) patients were determined to have mild neurological dysfunction or cerebral palsy, respectively. The rate of psychomotor abnormality according to a low Bayley Psychomotor Development Index (PDI) score was 24.8%, and the rate of mental/cognitive abnormality on the basis of a low Bayley Mental Development Index (MDI) score was 25.4%. In the subgroup of infants with < or = 29 weeks of gestational age (n = 55); 22 (40%) patients had an abnormal neurological examination, and 24 (43.6%) and 23 (41.8%) patients had low Bayley PDI and MDI scores, respectively. In the study group, logistic regression analysis revealed the significant predictors of an abnormal neurological examination to be the duration of mechanical ventilation (odds ratio [OR], 1.133; 95% confidence interval [CI], 1.062 to 1.208) and necrotizing enterocolitis (OR, 6.697; 95% CI, 1.776 to 25.252). One of the major conclusions of the present study is the risk of neurodevelopmental sequelae in one of every four preterm infants with <32 weeks of gestation and the need for follow-up in this group. Measures in neonatal care and treatment, such as the use of less traumatic modes of mechanical ventilation with as short duration as possible as well as increasing perinatal/antenatal care, should be taken to overcome these risk factors.

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A. Avni Atay

Military Medical Academy

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Erdal Gökçay

Military Medical Academy

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S. Umit Sarici

Military Medical Academy

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Ridvan Akin

Military Medical Academy

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Orhan Gürsel

Military Medical Academy

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Faruk Alpay

Military Medical Academy

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Turan Tunc

Military Medical Academy

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