doğan yücel

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Turkish journal of biochemistry is an open access journal again

Turkish Journal of Biochemistry

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Güncel Biyokimya Çalışmaları III

COVID-19 Enfeksiyonunda Hematolojik ve Enflamatuvar Parametrelerin İncelenmesi

Avrasya Sağlık Bilimleri Dergisi

AMAÇ: COVID-19 enfeksiyonu olan bireylerde, hastalığın şiddetini belirlemek, risk faktörlerini an... more AMAÇ: COVID-19 enfeksiyonu olan bireylerde, hastalığın şiddetini belirlemek, risk faktörlerini analiz etmek ve hastalığın prognozunu takip etmek için hematolojik ve enflamatuvar parametreler önemlidir. Bu parametreler yaş ve cinsiyete bağlı olarak değişim gösterebilir. Çalışmamızda COVID-19 enfeksiyonu olan hastaların Nötrofil/Lenfosit oranı (NLO), C-Reaktif Protein (CRP), Ferritin, Laktat Dehidrogenaz (LDH), D-Dimer ve Sistemik immün enflamasyon indeksi (Sİİ) parametrelerinin yaş ve cinsiyete göre değişimini incelemeyi amaçladık. YÖNTEM: Mart 2019 ve Ağustos 2021 tarihleri arasında Lokman Hekim Üniversitesi Ankara Hastanesi'ne başvuran ve PCR testi pozitif olan toplam 322 servis hastası (Kadın: 180, Erkek: 142) çalışmaya dahil edildi. Hastalar yaşlarına göre beş gruba ayrıldı (1.grup: 1-17 yaş; 2.grup: 18-30 yaş; 3.grup: 31-45 yaş; 4.grup: 46-60 yaş; 5.grup: 61-92 yaş). Hastaların laboratuvar sonuçları ve demografik bulguları retrospektif olarak incelendi. Gruplarda WBC, NLO, C...

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Serum undercarboxylated osteocalcin levels are related to bone disease in hemodialysis and peritoneal dialysis patients

The European Research Journal, 2021

Objectives: In our study, we investigated whether the undercarboxylated osteocalcin (ucOC) is an ... more Objectives: In our study, we investigated whether the undercarboxylated osteocalcin (ucOC) is an indicator of bone turnover for patients treated with hemodialysis (HD) or peritoneal dialysis (PD). Furthermore, we have examined the relationships between ucOC levels and other bone inidicators such as osteocalcin (OC), bone specific alkaline phosphatase (B-ALP), calcitonin, vitamin D, intact parathyroid hormone (iPTH), calcium (Ca), phosphate (P), magnesium (Mg) and bone mineral density (BMD). Methods: Study group was consisted of 24 HD, 30 PD patients and 30 control subjects. ucOC measurements were based on precipitation of carboxylated OC with barium sulfate. After precipitation, ucOC was measured in supernatant by ELISA. Results: In chronic kidney disease (CKD), increased ucOC levels were present both in HD and PD groups. The ucOC levels in HD group were higher than those of PD group. ucOC levels in samples after HD were lower than in samples before HD. But there is no difference be...

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Falsely Increased Free Triiodothyronine in Sera Stored in Serum Separator Tubes

Clinical Chemistry, 2002

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National External Quality Assessment follow-up: 2010–2017 Turkish experience

Turkish Journal of Biochemistry, 2019

ObjectiveMedical laboratories encounter critical obstacles in External Quality Assessment (EQA) p... more ObjectiveMedical laboratories encounter critical obstacles in External Quality Assessment (EQA) practices that are key to assessment of the analytical period. Present study aims to unveil the challenges in nationwide inter-laboratory harmonization and suggest practical solutions.Materials and methodsEQA results of 1941 laboratories participating in 18 different EQA-programs between 2010 and 2017 were examined. Standard Deviation Index (SDI) of each program calculated using 801,028 sample data from 24 different clinical chemical tests were used to conduct a process assessment.ResultsThere is a significant discrepancy in unsatisfactory performance ratio among different EAQ-programs with an average of 3.4% (27,074 cases) between 2010 and 2017 and a decreasing trend (~40–50%) in 7-years. Programs with higher SDI display lower discrepancy rates. Reasons for unaccepted results appear to be data entry errors (8.27–22.2%), material dilution errors (5–11.4%), technical problems (3.76–7.9%); ...

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<span class="caption">ORIGINAL ARTICLE</span>Is There a Relationship between Small, Dense LDL and Lipoprotein - Associated Phospholipase A2 Mass in Dialysis Patients?

Clinical Laboratory, 2014

ABSTRACT Background: We aimed to measure small, dense LDL (sdLDL) and lipoprotein-associated phos... more ABSTRACT Background: We aimed to measure small, dense LDL (sdLDL) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) concentrations and to evaluate their relationship with other risk factors of atherosclerotic heart disease in dialysis patients. Methods: Study group consisted of 30 peritoneal dialysis and 20 hemodialysis patients with 20 healthy control subjects. sdLDL was measured by homogeneous LDL assay after precipitation of Apo B containing lipoproteins with heparin-magnesium. Lp-PLA(2) mass was measured by immunoturbidimetric assay. Results: sdLDL concentrations in the samples collected before hemodialysis and peritoneal dialysis treatment were significantly higher than the control group (p &lt; 0.05). Lp-PLA(2) concentrations of both pre-hemodialysis and peritoneal dialysis groups were higher than control group (p &lt; 0.05). There was not a significant correlation between sdLDL and Lp-PLA(2). sdLDL concentrations are significantly decreased after a hemodialysis session. Conclusions: sdLDL and Lp-PLA(2) concentrations are increased independently in the end stage renal failure patients who are receiving dialysis treatment.

On the peer review process in scientific publication

Turkish Journal of Biochemistry, 2012

Bir bilimsel çalışmanın en somut ürünü makale olarak basılmasıdır. Yayın süreci yazarların yanı s... more Bir bilimsel çalışmanın en somut ürünü makale olarak basılmasıdır. Yayın süreci yazarların yanı sıra editör ve hakemlerin emeğine gerek gösterir. Bu süreçte editör kararına temel oluşturan en önemli bilgi hakemlerin raporlarına dayanır. Hakemler, makalede yer alan araştırma alanına hakim bilimcilerdir. Hakemlik sürecinde çalışmanın amacı, çalışmada kullanılan yöntemlerin amaca uygunluğu, sonuçların doğru verilişi ve doğru yorumlanışı, ama hepsinden öte, çalışmanın orijinalliği değerlendirilmelidir. Çalışma yeni bilgi veriyor mu, bilime katkı sağlıyor mu, soruları hakemin üzerinde yoğunlaşması gereken ve objektif olarak cevaplaması gereken sorulardır. Hakemler önyargısız ve yapıcı olmalıdır; sahtekarlık olmadıkça veya sunulan çok gereksiz ve yanlış bir çalışma değilse, yayını reddetmekten çok, kazanmaya çalışmalıdır. Hakem görüşleri çalışmanın daha da geliştirilmesi, bilim ortamına yenilikler getirmesi için en önemli aşamadır. Çalışmanın yayımlanabilmesi için giderilmesi gerekli eksiklikler hakemler tarafından yazara açık bir şekilde ifade edilmelidir. Gerekiyorsa yazarların bakış açısını genişletecek başka kaynaklar önerilmelidir. Hakemlik sürecinde en önemli noktalardan birisi de gizliliktir. Günümüzde çoğu dergide hakemler ve yazarlar gizli tutulur. Ancak açıklık yönünde bir eğilim vardır. Bazı dergilerde yazarların kimliği hakemlere açılmıştır. Bazı dergilerde ise hem yazarlar, hem de hakemlerin kimlik bilgileri birbirlerine açıktır. Hakemlik sürecinde, kuşkusuz, etik standartlara da dikkat edilmelidir. Günümüzde hakemlik süreci değişim halindedir. Gelecekte İnternet olanaklarıyla açık sisteme geçilme olasılığı vardır.

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A multicenter nationwide reference intervals study for common biochemical analytes in Turkey using Abbott analyzers

Clinical Chemistry and Laboratory Medicine (CCLM), 2014

A nationwide multicenter study was organized to establish reference intervals (RIs) in the Turkis... more 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.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).By ANOVA, differences of reference values among...

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Increased Nitrosative and Oxidative Stress in Platelets of Migraine Patients

The Tohoku Journal of Experimental Medicine, 2007

The molecular mechanisms of migraine have not been fully clarified yet. Increased nitrosative and... more The molecular mechanisms of migraine have not been fully clarified yet. Increased nitrosative and oxidative stress may be associated with migraine attacks. Platelets may play an important role in migraine patients and they can reflect the lability of tissues to nitrosative/oxidative stress. In the present study, we aimed to determine the levels of nitrosative and oxidative stress markers in platelets of migraine patients during headache-free and attack periods. A total of 56 subjects (22 migraine without aura, 14 migraine with aura, and 20 age-and sex-matched healthy controls) were included in the study and nitric oxide (NO) metabolites, malondialdehyde (MDA), and thiol (SH) groups were measured in platelets. During migraine attacks, platelet levels of nitrate, nitrite and MDA were significantly higher in migraineurs than these in control subjects (p = 0.042, p = 0.005 and p = 0.042, respectively). By contrast, during headache-free period, no statistically significant differences were found in the platelet levels of nitrate, nitrite and MDA between migraineurs and controls (p > 0.05), although the marginal increases were detected in migraineurs. These results suggest that increased biomarkers of nitrosative and oxidative stress in platelets may be important in migraine patients, especially during attacks; increase of NO metabolites in platelets during attacks supports the opinion that NO may play a modulatory role in biological processes particularly by vasodilatation in migraine attacks. Therefore, MDA and NO metabolites may serve as useful markers to show the increased vulnerability to nitrosative and oxidative stress in migraine patients. headache; migraine; nitric oxide; oxidative stress; nitrosative stress

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Best Oral Presentations (OP01-OP12)

Rheumatology, 2012

Background: The aim of this study was to determine the intima-media thickness (IMT) as an indicat... more Background: The aim of this study was to determine the intima-media thickness (IMT) as an indicator of subclinical atherosclerosis in carotid arteries and to assess the relation of these values with homocystein levels and Methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in patients with AS. Methods: Fifty male AS patients and 50 controls were included in the study. Serum lipids, vitamin B 12 , folic acid, homocystein and acute phase protein levels were measured in all cases. A plasma homocystein level of > 17 mmol/L was considered as hyperhomocysteinemia. MTHFR C677T gene polymorphisms were determined and IMT of main carotid artery were evaluated ultrasonographically in all subjects. BASDAI, ASDAS and BASMI were used to assess disease activity and spinal mobility. The relationship between plasma homocystein level, MTHFR C677T gene polymorphism, IMT values and clinical characteristics were determined. Results: Fifty AS patients (mean age of 36.6 AE 4.79 years) and 50 control subjects (36.34 AE 4.72 years) were included to the study. Demographic characteristic were smiliar between the groups. Plasma homocystein levels of AS patients and control group were also smiliar (14.26 AE 9.96 vs 11.81 AE 5.53 mmol/L). Hyperhomocysteinemia was present in 11 subjects in patient group (%22.0), while it was seen in 5 subjects in the control group (%10.0), and MTHFR C677T genotype distribution was CC 31 (%62), CT 14 (%28), TT 5 (%10) in AS patients and CC 26 (%52), CT 22 (%44), TT 2 (%4) in the control group, with no significant difference between groups (p ¼ 0.102, p ¼ 0.174) and the mean carotid IMT values were found to be similar between the groups. No relation was found between plasma homocystein levels and clinical and demographical properties. The most important factor influencing homocystein level was found as MTHFR 677TT genotype, which was established to increase the risk of hyperhomocyteinemia risk by 11.308 fold. Conclusions: In the present study, carotid IMT values, indicating subclinical atherosclerosis, were found to be similar in AS and control groups. The increase in the risk of atherosclerosis in AS patients seems not be different from healthy subjects. Disclosure statement: None.

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Automated Turbidimetric Benzalkonium Chloride Method for Measurement of Protein in Urine and Cerebrospinal Fluid

Clinical Chemistry, 2004

CoA hydratase, 3-methylcrotonyl-CoA carboxylase and 3-hydroxy-3-methylglutaryl-CoA lyase deficien... more

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Servikojenik Baş Ağrısı Olan Kadınlarda Serum Malondialdehit Düzeyleri

… Klinikleri J Med …, 2007

ÖZET Amaç: Servikojenik baş ağrısı (SBA) boyundaki yapılardan kaynaklanan oldukça sık görülen bir... more ÖZET Amaç: Servikojenik baş ağrısı (SBA) boyundaki yapılardan kaynaklanan oldukça sık görülen bir baş ağrısı şeklidir. Ağrı başlangıcının altında yatan mekanizmalar henüz tam olarak aydınlatılmış değildir. Bilgilerimize göre literatürde SBA ile oksidatif stres ilişkisini araştıran bir makale ...

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Diyet ve Simvastatin Tedavisinin Serum Lipid Profili ve HDL Subfraksiyonları Üzerine Olan Etkilerinin İncelenmesi

… Klinikleri J Med …, 2005

ÖZET Amaç: Bu çalışmada Koroner Kalp Hastalığı (KKH) açısından aterojenik risk indeksi olarak kab... more ÖZET Amaç: Bu çalışmada Koroner Kalp Hastalığı (KKH) açısından aterojenik risk indeksi olarak kabul edilen kolesterol/HDL-C oranı > 5.6 olan hastalarda diyet ve simvastatin tedavilerinin serum lipid profili ve HDL subfraksiyonları üzerine olan etkileri araştırıldı. Gereç ve Yöntemler: ...

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Effect of Addition of Hemolysate on Urine and Cerebrospinal Fluid Assays for Protein

Clinical Chemistry, 2006

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Evaluation of oxidative stress in bladder in urethral injuries: an experimental model in rats

Revista Romana de Medicina de Laborator, 2020

Background: The aim of this study is to determine the changes of some oxidative stress parameters... more Background: The aim of this study is to determine the changes of some oxidative stress parameters following an experimental urethral injury. Materials and Methods: 24 Wistar-Albino male rats were used and 18 of them were exposed to urethral injury. Total oxidant status (TOS) and total antioxidant capacity (TAC) values in bladder and penile tissues and sera of rats during creation and healing stages of injury (control, day-1, 7 and 21) were examined and evaluated histopathologically. Results: TOS levels in both tissue and serum groups increased nearly 4x fold in first day following injury. On the seventh day, TOS levels of bladder and penile tissue showed a nearly 50% decrease according to first day (p=0.005; p=0.025, respectively). At the end of third week, while bladder TOS levels decreased to control values, penile tissue TOS levels remained at high levels. The bladder TAC values mildly increased in first day (p=0.026) and then returned to normal levels in seventh day and continue...

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Compatibility of the Results of an Automated Urine Analyzer with Urine Culture

Objectives: We aimed to evaluate incidence of leukocyte esterase (LE) and nitrite positivity, leu... more Objectives: We aimed to evaluate incidence of leukocyte esterase (LE) and nitrite positivity, leukocyte and bacterial counts in urine, and Gram positive and negative bacterial results interpreted by an automated urine analyzer for compliance with culture results. Materials and Methods: 3194 urinalysis results were examined retrospectively. Measurements were made on Sysmex UF-5000 automated urine analyzer. Gram positive and negative bacterial interpretations were compared with results of culture. Results: Out of 889 patients with bacterial interpretation, 577 were Gram positive and 312 were Gram negative. There were 6 positive culture results in Gram positive group (2 E. faecalis, 4 S. Agalactia) and 61 positive culture results in Gram negative group (52 E. coli, 4 K. pneumoniae, 5 P. Aeuroginosa). As incompatible with results of culture, incorrect gram-stain interpretations were made by the analyzer in 3 samples (1 K. Pneumoniae, 2 Candida spp) in Gram positive group and in 3 sample...

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Correlation between Anaemia and Hepcidin-25 and Interleukin 6 Levels in Early Stage and Advanced Chronic Renal Disease

West Indian Medical Journal, 2016

Background: Anemia is very commonly seen complication in the patients with chronic renal disease ... more Background: Anemia is very commonly seen complication in the patients with chronic renal disease (CRD). This is thought to result from decreased renal excretion of the hepcidin and chronic inflammatory process. Our study aimed to investigate the correlation between hemoglobin (Hb) and hepcidin levels in all stages starting from stage 2 CRD. Method: The study was conducted on a total of 80 patients with stage 2-3-4-5 chronic renal disease who have not been treated with renal replacement therapy, including 20 patients from each stage. In all groups, C-reactive protein (CRP), high sensitivity C-reactive protein (HsCRP), interleukin 6 (IL 6), hepcidin-25, routine biochemistry, whole blood count, iron, total iron binding capacity (TIBC), ferritin, folic acid and Vitamin B12 were measured. Results: When the patients were evaluated for inflammatory parameters, CRP (p=0.01), HsCRP (p=0.01), erythrocyte sedimentation rate (ESR) (p=0.001), IL 6 (p=0.001), ferritin (p=0.02), hepcidin-25 (p=0.03) levels were significantly higher in the group with advanced stage compared to the group with early stage. It was determined that hemoglobin (Hb) level was statistically significantly lower in advanced CRD compared to early stage CRD (p<0.001). Conclusion: Using the agents that may decrease the levels of hepcidin may be useful to increase Hb levels in the treatment of anemia in the patients with chronic renal disease.

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Dose-dependent effects of ghrelin and aberrant anti-Mullerian hormone levels in the prevention of ovarian damage caused by cisplatin in Wistar-albino rats

Archives of Gynecology and Obstetrics, 2021

Ghrelin has previously been proven to have anti-inflammatory and antioxidant properties in preven... more Ghrelin has previously been proven to have anti-inflammatory and antioxidant properties in preventing cisplatin-induced ovarian damage. The aim of this study was to evaluate the potential effects of this hormone in preventing this damage in rats using histopathological and biochemical methods. Twenty-eight Wistar-albino rats were randomly divided into four groups. While no drug was given to Group 1 (sham group), acylated ghrelin was intraperitoneally administered to Group 2 at 0.5 nmol/kg and Group 3 at 2 nmol/kg for 21 days. Group 4 received only saline solution. On the 15th day, a single dose of 5 mg/kg cisplatin was intraperitoneally administered to each rat in Groups 2, 3 and 4. Serum anti-Mullerian hormone (AMH) values were measured on days 0, 15 and 21. Then, laparotomy and bilateral oophorectomy were performed, and the ovaries were histopathologically examined. The number of primordial and primary follicles was significantly higher in Group 3 than in the saline solution + cisplatin group. In Group 4, cisplatin caused significantly higher follicle damage in the primordial, primary and secondary phases compared to the sham group. The AMH level of the SF + cisplatin group was significantly lower than that of the sham group and the high-dose ghrelin + cisplatin group, and the AMH level of the sham group was significantly higher than that of the low-dose ghrelin + cisplatin group. High-dose ghrelin was effective in preventing cisplatin-induced ovarian damage by preserving the number of primordial and primary follicles. Larger randomized studies are needed to determine the optimal dosage and duration of ghrelin.

HDL subgroups and their paraoxonase‐1 activity in the obese, overweight and normal weight subjects

International Journal of Clinical Practice, 2021

ABSTRACT Background: Obesity and overweight are significant public health problems due to higher ... more ABSTRACT Background: Obesity and overweight are significant public health problems due to higher risk for coronary artery disease (CAD). It is very important to determine new predictive markers to identify the CAD risk in obese and overweight. To this aim, we analyzed HDL-C subclass and their paraoxonase-1 (PON-1) activity in obese, overweight and normal weight subjects. Method: 71 newly diagnosed obese, 40 overweight and 30 healthy subjects as a control group were enrolled the study. Serum lipids levels were determined with enzymatic colorimetric method. PON-1 activities and HDL-3 levels were determined by spectrophotometric methods. Non-HDL3-C concentrations were calculated with the subtraction of HDL3-C from total HDL-C. Results: The mean serum levels of total HDL-C, HDL3-C, Non-HDL3-C -C and ApoA1 were higher in control group than obese and overweight groups. There were a statistically significant difference between obese and control group in terms of Lp(a), hsCRP and HOMA index. Higher total PON-1, non-HDL3 PON-1 and HDL3 PON-1 activities were found in the control group compared to obese and overweight groups. Total HDL was weakly negative correlated with the HOMA index, BMI and waist circumference. There was a weak negative correlation between non-HDL3-C and waist circumstance. Conclusion: Abnormal HDL-subgroups pattern and decreased PON-1 activities causes increased risk for CVD in obese and overweight individuals. Therefore determination of HDL subgroups and their PON-1 activity improves risk prediction compared with measuring total HDL-C levels and its PON-1 activity alone. Body weight and insulin resistance appear to have a role in the decreased HDL-C levels and PON-1activity in obese.

Turkish journal of biochemistry is an open access journal again

Turkish Journal of Biochemistry

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Güncel Biyokimya Çalışmaları III

COVID-19 Enfeksiyonunda Hematolojik ve Enflamatuvar Parametrelerin İncelenmesi

Avrasya Sağlık Bilimleri Dergisi

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Serum undercarboxylated osteocalcin levels are related to bone disease in hemodialysis and peritoneal dialysis patients

The European Research Journal, 2021

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Falsely Increased Free Triiodothyronine in Sera Stored in Serum Separator Tubes

Clinical Chemistry, 2002

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National External Quality Assessment follow-up: 2010–2017 Turkish experience

Turkish Journal of Biochemistry, 2019

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<span class="caption">ORIGINAL ARTICLE</span>Is There a Relationship between Small, Dense LDL and Lipoprotein - Associated Phospholipase A2 Mass in Dialysis Patients?

Clinical Laboratory, 2014

On the peer review process in scientific publication

Turkish Journal of Biochemistry, 2012

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A multicenter nationwide reference intervals study for common biochemical analytes in Turkey using Abbott analyzers

Clinical Chemistry and Laboratory Medicine (CCLM), 2014

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Increased Nitrosative and Oxidative Stress in Platelets of Migraine Patients

The Tohoku Journal of Experimental Medicine, 2007

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Best Oral Presentations (OP01-OP12)

Rheumatology, 2012

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Automated Turbidimetric Benzalkonium Chloride Method for Measurement of Protein in Urine and Cerebrospinal Fluid

Clinical Chemistry, 2004

CoA hydratase, 3-methylcrotonyl-CoA carboxylase and 3-hydroxy-3-methylglutaryl-CoA lyase deficien... more

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Servikojenik Baş Ağrısı Olan Kadınlarda Serum Malondialdehit Düzeyleri

… Klinikleri J Med …, 2007

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Diyet ve Simvastatin Tedavisinin Serum Lipid Profili ve HDL Subfraksiyonları Üzerine Olan Etkilerinin İncelenmesi

… Klinikleri J Med …, 2005

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Effect of Addition of Hemolysate on Urine and Cerebrospinal Fluid Assays for Protein

Clinical Chemistry, 2006

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Evaluation of oxidative stress in bladder in urethral injuries: an experimental model in rats

Revista Romana de Medicina de Laborator, 2020

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Compatibility of the Results of an Automated Urine Analyzer with Urine Culture

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Correlation between Anaemia and Hepcidin-25 and Interleukin 6 Levels in Early Stage and Advanced Chronic Renal Disease

West Indian Medical Journal, 2016

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Dose-dependent effects of ghrelin and aberrant anti-Mullerian hormone levels in the prevention of ovarian damage caused by cisplatin in Wistar-albino rats

Archives of Gynecology and Obstetrics, 2021

HDL subgroups and their paraoxonase‐1 activity in the obese, overweight and normal weight subjects

International Journal of Clinical Practice, 2021

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