Browsing by Author "Akan, P"

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    Alterations in BDNF (brain derived neurotrophic factor) and GDNF (glial cell line-derived neurotrophic factor) serum levels in bipolar disorder: The role of lithium
    Tunca, Z; Ozerdem, A; Ceylan, D; Yalçin, Y; Can, G; Resmi, H; Akan, P; Ergor, G; Aydemir, Ö; Cengisiz, C; Doyurana, K
    Objective: Brain-derived neurotrophic factor (BDNF) has been consistently reported to be decreased in mania or depression in bipolar disorders. Evidence suggests that Glial cell line-derived neurotrophic factor (GDNF) has a role in the pathogenesis of mood disorders. Whether GDNF and BDNF act in the same way across different episodes in bipolar disorders is unclear. Method: BDNF and GDNF serum levels were measured simultaneously by enzyme-linked immunosorbent assay (ELISA) method in 96 patients diagnosed with bipolar disorder according to DSM-IV (37 euthymic, 33 manic, 26 depressed) in comparison to 61 healthy volunteers. SCID-I and SCID-non patient version were used for clinical evaluation of the patients and healthy volunteers respectively. Correlations between the two trophic factor levels, and medication dose, duration and scrum levels of lithium or valproate were studied across different episodes of illness. Results: Patients had significantly lower BDNF levels during mania and depression compared to euthymic patients and healthy controls. GDNF levels were not distinctive. However GDNF/BDNF ratio was higher in manic state compared to euthymia and healthy controls. Significant negative correlation was observed between BDNF and GDNF levels in euthymic patients. While BDNF levels correlated positively, GDNF levels correlated negatively with lithium levels. Regression analysis confirmed that lithium levels predicted only GDNF levels positively in mania, and negatively in euthymia. Limitations: Small sample size in different episodes and drug-free patients was the limitation of thestudy. Conclusion: Current data suggests that lithium exerts its therapeutic action by an inverse effect on BDNF and GDNF levels, possibly by up regulating BDNF and down regulating GDNF to achieve euthymia. (C) 2014 Elsevier B.V. All rights reserved.
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    A multicenter nationwide reference intervals study for common biochemical analytes in Turkey using Abbott analyzers
    Ozarda, Y; Ichihara, K; Aslan, D; Aybek, H; Ari, Z; Taneli, F; Coker, C; Akan, P; Sisman, AR; Bahceci, O; Sezgin, N; Demir, M; Yucel, G; Akbas, H; Ozdem, S; Polat, G; Erbagci, AB; Orkmez, M; Mete, N; Evliyaoglu, O; Kiyici, A; Vatansev, H; Ozturk, B; Yucel, D; Kayaalp, D; Dogan, K; Pinar, A; Gurbilek, M; Cetinkaya, CD; Akin, O; Serdar, M; Kurt, I; Erdinc, S; Kadicesme, O; Ilhan, N; Atali, DS; Bakan, E; Polat, H; Noyan, T; Can, M; Bedir, A; Okuyucu, A; Deger, O; Agac, S; Ademoglu, E; Kaya, A; Nogay, T; Eren, N; Dirican, M; Tuncer, G; Aykus, M; Gunes, Y; Ozmen, SU; Kawano, R; Tezcan, S; Demirpence, O; Degirmen, E
    Background: A nationwide multicenter study was organized to establish reference intervals (RIs) in the Turkish population for 25 commonly tested biochemical analytes and to explore sources of variation in reference values, including regionality. Methods: Blood samples were collected nationwide in 28 laboratories from the seven regions (>= 400 samples/region, 3066 in all). The sera were collectively analyzed in Uludag University in Bursa using Abbott reagents and analyzer. Reference materials were used for standardization of test results. After secondary exclusion using the latent abnormal values exclusion method, RIs were derived by a parametric method employing the modified Box-Cox formula and compared with the RIs by the non-parametric method. Three-level nested ANOVA was used to evaluate variations among sexes, ages and regions. Associations between test results and age, body mass index (BMI) and region were determined by multiple regression analysis (MRA). Results: By ANOVA, differences of reference values among seven regions were significant in none of the 25 analytes. Significant sex-related and age-related differences were observed for 10 and seven analytes, respectively. MRA revealed BMI-related changes in results for uric acid, glucose, triglycerides, high-density lipoprotein (HDL)-cholesterol, alanine aminotransferase, and.-glutamyltransferase. Their RIs were thus derived by applying stricter criteria excluding individuals with BMI >28 kg/m(2). Ranges of RIs by non-parametric method were wider than those by parametric method especially for those analytes affected by BMI. Conclusions: With the lack of regional differences and the well-standardized status of test results, the RIs derived from this nationwide study can be used for the entire Turkish population.