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Dive into the research topics where Mehmet Kantar is active.

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Featured researches published by Mehmet Kantar.


Leukemia & Lymphoma | 2009

Methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms and therapy-related toxicity in children treated for acute lymphoblastic leukemia and non-Hodgkin lymphoma

Mehmet Kantar; Buket Kosova; Nazan Çetingül; Sevinc Gumus; Ertug Toroslu; Nur Zafer; Nejat Topcuoglu; Serap Aksoylar; Mehtap G. Çınar; Asli Tetik; Zuhal Eroglu

This study aimed to investigate the association of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms with serum drug levels and toxicities after high-dose methotrexate (MTX) infusion. The study included 37 children with acute lymphoblastic leukemia or non-Hodgkin lymphoma. Serum MTX levels and toxicities of bone marrow, liver and kidney were analysed. Genotype analysis of the C677T and A1298C gene polymorphisms from genomic DNA of the subjects was performed by real-time PCR. Subjects with MTHFR polymorphism for C677T (CT, TT) had significantly higher MTX levels at 24 h (p = 0.009), and these genotypes did not seem to cause toxicity. Subjects with MTHFR polymorphism for A1298C (AC, CC) had significantly higher MTX levels at 48 h (p = 0.02), and had more grade III/IV anemia (p = 0.02), thrombocytopenia (p = 0.0001), elevated AST levels (p = 0.04) and frequent febrile neutropenic episodes (p = 0.004). The present study suggests that A1298C gene, but not C677T polymorphism is associated with MTX-related toxicity.


Acta Haematologica | 1999

Sequential Use of Deferiprone and Desferrioxamine in Primary School Children with Thalassaemia major in Turkey

Yesim Aydinok; Nişli G; Canan Çoker; Mehmet Kantar; Nazan Çetingül

The effectiveness of the sequential use of deferiprone and desferrioxamine (DFO) in children with thalassaemia major was examined. Seven thalassaemic children in whom urinary iron induced by deferiprone was sufficient to maintain a negative iron balance were enrolled in the long-term trial. Deferiprone at a dose of 75 mg/kd/day in 3 divided doses was given for 4 school days a week. The group was given DFO at a dose of 40–50 mg/kg/day s.c. over 8–12 h with a battery-operated pump for 2 days at the weekend. In addition to the safety variables, they were monitored for serum ferritin levels at 2-month intervals and hepatic iron concentrations in liver tissues were determined at the beginning and the 6th month of therapy. The severity of hepatic damage was graded according to the Knodell hepatic activity index and the fibrosis was quantified. None of the patients suffered adverse effects of the therapy but a transient increase in serum ALT levels was noted. A nonsignificant decline in serum ferritin was observed (p = 0.08), a significant reduction in hepatic iron concentration was also determined (p = 0.03). The hepatic activity index in liver tissues of the patients at the 6th month of the sequential therapy significantly decreased (p = 0.03) whereas fibrosis scores did not differ significantly (p = 0.25).


Journal of Tropical Pediatrics | 2002

Endocrine Complications in Patients with β‐thalassemia Major

Yesim Aydinok; Sukran Darcan; Aziz Polat; Nişli G; Mahmut Çoker; Mehmet Kantar; Nazan Çetingül

Thirty-seven patients with thalassemina major (TM) were studied to determine the extent and rate of endocrine complications. Mean haemoglobin and ferritin concentrations were 8.8 +/- 0.6 and 3,597 +/- 1,931, respectively. Provocation tests for growth hormone secretion were applied in patients with standing heights below the third centile and/or growth velocities below the 10th centile. Sexual maturation was assessed by using the criteria of Tanner. Glucose metabolism was assessed by fasting plasma glucose and glucose tolerance test. Basal thyroid function was measured and thyrotropin-releasing hormone tolerance test was carried out. Growth retardation was found in 40 per cent of patients and growth hormone deficiency was a prominent cause of growth retardation. Gonadal dysfunction was detected in 47 per cent of patients. Hypothyroidism was observed in 16 per cent and impaired glucose metabolism in 10.8 per cent patients. The high rate of endocrine disturbances indicates the importance of regular follow-up of thalassemia major patients with regard to endocrine complications of the disease.


European Journal of Pediatrics | 2000

Plasma concentrations of granulocyte-macrophage colony-stimulating factor and interleukin-6 in septic and healthy preterms.

Mehmet Kantar; Nilgun Kultursay; Necil Kutukculer; Mete Akisu; Nazan Çetingül; Suat Caglayan

Abstract Plasma granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) concentrations were determined in 21 preterm infants with sepsis and nine healthy preterm neonates of the same postnatal age at sampling. Plasma GM-CSF levels were elevated at diagnosis in the septic preterms as compared to the healthy preterms (P = 0.01), but did not differ significantly on recovery. IL-6 levels were also elevated markedly at diagnosis (P = 0.0003), but decreased to normal on recovery as compared to the healthy preterm infants. GM-CSF levels were more prominent in septic preterms with neutropenia than those of non-neutropenic infants (P = 0.03). Conclusion Preterm infants can produce high levels of granulocyte-macrophage colony-stimulating factor and interleukin-6 in response to bacterial sepsis.


Oncology Nursing Forum | 2009

Complementary and Alternative Medicine Used by Pediatric Patients With Cancer in Western Turkey

Rabia Ekti Genç; Selmin Senol; Ayse San Turgay; Mehmet Kantar

PURPOSE/OBJECTIVES To determine the extent of complementary and alternative medicine (CAM) use, the types of therapies employed, and the reasons for choosing those therapies. DESIGN Descriptive type, cross-sectional. SETTING Pediatric oncology department in western Turkey. SAMPLE 112 children receiving or completing treatment for cancer. METHODS Parents of 112 children completed a questionnaire regarding CAM use. Analyses included examining correlations between CAM use and demographic variables. MAIN RESEARCH VARIABLES CAM use and demographic variables. FINDINGS 77% of the patients used one or more type of CAM, with herb use being the most common. CONCLUSIONS About 75% of parents used CAM for their children. However, about 25% sought discussion with the physician about the CAM they were using. IMPLICATIONS FOR NURSING Nurses should approach their patients without prejudice, gather information about the various CAM techniques, and share this knowledge with their patients.


Pediatric Hematology and Oncology | 2004

Meropenem Plus Amikacin Versus Piperacillin-Tazobactam Plus Netilmicin as Empiric Therapy for High-Risk Febrile Neutropenia in Children

Serap Aksoylar; Nazan Çetingül; Mehmet Kantar; Deniz Yilmaz Karapinar

The aim of this study was to evaluate the efficacy and safety of meropenem plus amikacin compared with piperacillin-tazobactam plus netilmicin for initial empirical antibiotic treatment of high-risk febrile neutropenia in children with cancer. Patients with hematologic malignancy (leukemia or stage III/IV non-Hodgkin lymphoma) who presented with fever and neutropenia (ANC < 500/mm3) and patients with solid tumors who presented with fever and severe neutropenia (ANC < 100/mm3) were considered to be at high risk and eligible for this study. In this prospective study, 33 patients with 50 febrile neutropenic episodes received iv meropenem (20 mg/kg every 8 h) plus amikacin (15 mg/kg/d in 2 divided doses) (in 31 episodes) or piperacillin/tazobactam (100 mg/4 mg/kg every 8 h) plus netilmicin (7 mg/kg every 24 h) (in 19 episodes). Clinical response was determined at 72 h and at completion of the therapy. The groups were comparable in terms of age, sex, initial ANC, use of growth factors, and classification of the infections. An infection was documented microbiologically in 12 episodes (39%) in the meropenem plus amikacin group and in 8 episodes (42%) in the piperacillin/tazobactam plus netilmicin group. Of the 22 microbiological isolates, 37% were gram-positives, 45% were gram-negatives, and 18% were fungi. Most of the clinically documented infections were of lower respiratory tract, gastrointestinal mucosa, or urinary tract origin. The mean duration of neutropenia was 9 days in both groups. Fever persisted for 1–30 days (mean 3 vs. 5 days). The success rate with initial empiric therapy was 52% in the meropenem plus amikacin and 42% in the piperacillin/tazobactam plus netilmicin group, respectively (p= .5). Total success rate (with or without modification) was 97% vs. 90% in the episodes. Three patients died due to infection (1 vs. 2 patients). No major adverse effects were observed in each group. Empirical therapy with meropenem plus amikacin or piperacillin/tazobactam plus netilmicin for high-risk febrile neutropenia is equally effective and safe in pediatric cancer patients.


Pediatrics International | 2006

Sedation with intravenous ketamine and midazolam for painful procedures in children

Bulent Karapinar; Deniz Yilmaz; Kubilay Demirag; Mehmet Kantar

Background: Children often require relief of pain and anxiety when undergoing painful procedures. The purpose of this study is to evaluate the effectiveness and safety of painful pediatric procedures performed by pediatric intensivist, using the combination of intravenous ketamine and midazolam for sedation and analgesia.


Pediatric Hematology and Oncology | 2002

RARE TUMORS OF THE LUNG IN CHILDREN

Mehmet Kantar; Nazan Çetingül; Ali Veral; Coşkun Özcan; Hüdaver Alper

The authors report rare and different types of lung tumors in 4 children. The first case is an 8-year-old boy with mucoepidermoid carcinoma, the second case is a 9-year-old girl with neuroendocrine carcinoma, the third is a 14-year-old girl with fetal lung adenocarcinoma (FLAC), and the last is a 16-year-old girl with bronchioloalv eolar carcinoma. Among these tumors, FLAC has not been reported in children so far. Each tumor type displayed a different prognosis in the follow-up period. In the differential diagnosis of primary lung tumors, carcinoid tumor, bronchogenic carcinoma, and pulmonary blastoma are frequently encountered, but these rare tumor types should be borne in mind.


Pediatric Hematology and Oncology | 2004

A SINGLE INSTITUTIONAL EXPERIENCE: Is Epoetin Alpha Effective in Anemic Children with Cancer?

Deniz Yilmaz; Nazan Çetingül; Mehmet Kantar; Haldun Öniz

The authors aimed to investigate the efficacy of epoetin-alpha on hemoglobin levels and red cell transfusion requirement in children with both hematologic malignancy (HM, n = 27) and solid tumors (ST, n = 14). Epoetin-alpha was given (150 U/kg or 250 U/kg, thrice weekly) for 12 weeks. Epoetin alpha significantly increased the hemoglobin levels at the 2nd and 3rd months of therapy (p <. 05). At the 3rd month, the patients required less red cell transfusion. At the dose of 150 U/kg, only three patients with HM, but none of the ST patients, required red cell. However, none required red cell transfusion after 2nd month on epoetin alpha 250 U/kg. Epoetin-alpha administration increases hemoglobin levels and decreases red cell transfusion requirement in children with malignancy.


Leukemia & Lymphoma | 2004

Evaluation of telomerase mRNA (hTERT) in childhood acute leukemia

Ozgur Cogulu; Buket Kosova; Emin Karaca; Cumhur Gunduz; Ferda Ozkinay; Serap Aksoylar; Hüseyin Gülen; Mehmet Kantar; Haldun Öniz; Deniz Yilmaz Karapinar; Nazan Çetingül; Ayşe Erbay; Canan Vergin; Cihangir Ozkinay

Human telomerase reverse transcriptase (hTERT) is the catalytic component of telomerase enzyme and has been shown to be associated with telomerase activity (TA). Although many studies in adult leukemia have established the importance of TA, very few have been reported in the children. In this study hTERT levels in childhood leukemia was evaluated and compared with the prognostic factors described before. The LightCycler instrument was used (online real-time PCR) for the quantification of hTERT in peripheral blood and bone marrow in 23 cases with acute lymphoblastic leukemia (ALL) and in 8 cases with acute myeloblastic leukemia (AML). Ten cases with normal peripheral blood (PB) and bone marrow (BM) were selected as control group. Cytogenetic analyses were available in 21 patients with leukemia. In all cases with acute leukemia and in control group, peripheral blood (PB) hTERT levels correlated significantly with bone marrow (BM) hTERT levels. Before treatment, patients with ALL had significantly higher hTERT levels than that of AML patients and control cases. Among patients with ALL, higher hTERT levels were observed in patients with pre-B leukemia, followed by B cell and T cell leukemia patients. Initially increased hTERT levels decreased to the nearly normal levels during remission in cases with ALL. No correlation was observed between the initial hTERT levels and the known prognostic factors except cytogenetic findings. Higher hTERT levels were detected in patients having karyotypic abnormalities which indicate poor prognosis. hTERT levels are significantly high in childhood ALL with the highest level of pre-B cell leukemia before treatment. Those high levels of hTERT decrease to almost normal levels in remission. hTERT levels might be useful in monitoring of leukemia in children.

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