Araştırma Çıktıları
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Item National External Quality Assessment follow-up: 2010-2017 Turkish experience(WALTER DE GRUYTER GMBH, 2019-01-01) Mercan, Ferzane; Serdar, Muhittin A.; Senes, Mehmet; Konukoglu, Dildar; Inal, Tamer Cevat; Alatas, Ozkan; Pinar, Asli; Savci, Ozlem; Guven, Muhammet; Gunduz, Mehmet; Egin, Ertugrul; Tipioglu, Yasal Onder; Tekin, Ahmet; Yucel, DoganObjective: Medical 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 interlaboratory harmonization and suggest practical solutions. Materials and methods: EQA 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. Results: There 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 (similar to 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\%)Item A Simple Method for Quantification of Five Urinary Porphyrins, Porphobilinogen and 5-Aminolevulinic Acid, Using Liquid Chromatography Tandem Mass Spectrometry(SPRINGER INDIA, 2019-01-01) Dogan, Ozlem; Serdar, Muhittin A.; Murat, Koza; Sonmez, Cigdem; Ispir, Emre; Serteser, Mustafa; Unsal, IbrahimAnalysis of porphyrins and 5-aminolevulinic acid (ALA), porphobilinogen (PBG) in physiological liquids is required for diagnosis and follow-up of porphyrias. High performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LC-MS) methods with higher specificity and sensitivity have been developed. The major disadvantage of those methods is that they require longer extraction times due to their matrix effects. The present study suggests a simple, fast, sensitive, and specific assay for determination of Coproporphyrin, 5-carboxylporphyrin, 6-carboxylporphyrin, 7-carboxylporphyrin, Uroporphyrin I and ALA, PBG in urine sample by direct injection without sample pre-treatment using LC-MS. For the purposes of the present study LC-MS device was set to multiple reaction monitoring (MRM) and positive ion mode. Porphyrins and ALA, porphobilinogen were characterized by their MS/MS product ion, spectra. ALA, PBG and 5 porphyrins were detected simultaneously. Limit of detection for Coproporphyrin, 5-carboxylporphyrin, 6-carboxylporphyrin, 7-carboxylporphyrin, Uroporphyrin I were 2nmol/L, where it was 5mol/L for ALA and 2mol/L for porphobilinogen. The present study suggests that the present method is very effective compared to many other available methods for it does not require pre-treatment, provides simultaneous results of ALA, PBG and 5 porphyrins quantitatively in a shorter span of time, and has suitable sensitivity and selectivity. LC-MS technique was used clinically for the determination of urine porphyrin levels.Item Differential expression of full-length and NH2 terminally truncated FAM134B isoforms in normal physiology and cancer(AMER PHYSIOLOGICAL SOC, 2020-01-01) Keles, Umur; Iscan, Evin; Yilmaz, Huriye Erbak; Karakulah, Gokhan; Suner, Asli; Bal, Erhan; Tasdemir, Nilgun; Cavga, Ayse Derya; Ekin, Umut; Mutlu, Zeynep; Kahyaoglu, Sila; Serdar, Muhittin A.; Atabey, Nese; Ozturk, MehmetSelective autophagy of the endoplasmic reticulum (ER), namely ER-phagy, is mediated by ER-localized receptors, which are recognized and sequestered by GABARAP/LC3B-decorated phagophores and transferred to lysosomes for degradation. Being one such receptor, FAM134B plays critical roles in cellular processes such as protein quality control and neuronal survival. FAM134B has also been associated with different cancers, although its exact role remains elusive. We report here that the FAM134B gene encodes not one but at least two different protein isoforms: the full-length and the NH2 terminally truncated forms. Their relative expression shows extreme variation, both within normal tissues and among cancer types. Expression of full-length FAM134B is restricted to the brain, testis, spleen, and prostate. In contrast, NH2 terminally truncated FAM134B is dominant in the heart, skeletal muscle, kidney, pancreas, and liver. We compared wild-type and knockout mice to study the role of the Fam134b gene in starvation. NH2 terminally truncated FAM134B-2 was induced in the liver, skeletal muscle, and heart but not in the pancreas and stomach following starvation. Upon starvation, Fam134b(-/-) mice differed from wild-type mice by less weight loss and less hyperaminoacidemic and hypocalcemic response but increased levels of serum albumin, total serum proteins, and a-amylase. Interestingly, either NH2 terminally truncated FAM134B or both isoforms were downregulated in liver, lung, and colon cancers. In contrast, upregulation was observed in stomach and chromophobe kidney cancers. NEW \& NOTEWORTHY We reported tissues expressing FAM134B2 such as the kidney, muscle, heart, and pancreas, some of which exhibit stimulated expression upon nutrient starvation. We also demonstrated the effect of Fam134b deletion during ad libitum and starvation conditions. Resistance to weight loss and hypocalcemia, accompanied by an increase in serum albumin and alpha-amylase levels, indicate critical roles of Fam134b in physiology. Furthermore, the differential expression of FAM134B isoforms was shown to be significantly dysregulated in human cancers.Item Comparison of four immunoassay analyzers for relationship between thyroid stimulating hormone (TSH) and free thyroxine (FT4)(TURKISH BIOCHEM SOC, 2015-01-01) Serdar, Muhittin A.; Ispir, Emre; Ozgurtas, Taner; Gulbahar, Ozlem; Ciraci, Zahid; Pasaoglu, Hatice; Kurt, IsmailObjective: There is an inverse log/linear relationship between TSH and FT4 due to the negative feedback of these hormones on the pituitary. The objective of our study was to compare this relationship of TSH and FT4 between four different immunoassay analyzers. Methods: In our study, four data sets obtained from the database of four different hospital laboratories each using only a single method of measurement was used to evaluate this relationship between TSH and FT4. These data sets with their assay methods include: 21.102 test results measured by Modular E170 Analyzer (Roche Diagnostics, Germany), 20.241 test results measured by Access DxI 800 Unicel (Beckman Coulter, USA), 22.444 test results measured by Architect i2000sr (Abbott Laboratories, Abbott Park, Illinois, U.S.A) and 20.200 test results measured by ADVIA Centaur XP (Siemens Diagnostics, Tarrytown, NY). Inverse logarithmic relationship were determined from each data sets and compared between analyzers. Results: The correlation coefficients were -0.439 {[}95\% CI, (-0.450)- (-0.428)], -0.488 {[}95\% CI, (-0.498)- (-0.478)], -0.353 {[}95\% CI, (-0.364)- (-0.342)], -0.430 {[}95\% CI, (-0.441)- (-0.419)] for DxI 800 Unicel, Modular E 170, Architect i2000sr and ADVIA Centaur XP, respectively. In our study, all immunoassay analyzers showed poor correlation in a concentration range of TSH between 1.0 to 10.0 uIU/mL and the inverse log/linear relationship was not observed. Inverse relationship between TSH and FT4 is the result of negative thyroid pituitary hypothalamic feedback mechanism and this relationship is important especially in the diagnosis and treatment of hypo and hyperthyroidism. In data sets obtained from four different immunoassay analyzers, poor and statistically different correlation was observed between analyzers at TSH values ranged from 1.0 to 10.0 uIU/mL compared with FT4. Conclusion: These variations between analyzers may affect the clinical decisions especially in the evaluation of subclinical hypothyroidism, clinicians and laboratory specialists should be aware of these situation.Item Association Between Early Idiopathic Neonatal Jaundice and Urinary Tract Infections(SAGE PUBLICATIONS LTD, 2017-01-01) Ozcan, Murat; Sarici, S. Umit; Yurdugul, Yuksel; Akpinar, Melis; Altun, Demet; Ozcan, Begum; Serdar, Muhittin A.; Sarici, DilekBackground and purpose: Etiologic role, incidence, demographic, and response-to-treatment characteristics of urinary tract infection (UTI) among neonates, its relationship with significant neonatal hyperbilirubinemia, and abnormalities of the urinary system were studied in a prospective investigation in early (<= 10 days) idiopathic neonatal jaundice in which all other etiologic factors of neonatal hyperbilirubinemia were ruled out. Patients and methods: Urine samples for microscopic and bacteriologic examination were obtained with bladder catheterization from 155 newborns with early neonatal jaundice. Newborns with a negative urine culture and with a positive urine culture were defined as group I and group II, respectively, and the 2 groups were compared with each other. Results: The incidence of UTI in whole of the study group was 16.7\%. Serum total and direct bilirubin levels were statistically significantly higher in group II when compared with group I (P = .005 and P = .001, respectively). Decrease in serum total bilirubin level at the 24th hour of phototherapy was statistically significantly higher in group I compared with group II (P =.022). Conclusions: Urinary tract infection should be investigated in the etiologic evaluation of newborns with significant hyperbilirubinemia. The possibility of UTI should be considered in jaundiced newborns who do not respond to phototherapy well or have a prolonged duration of phototherapy treatment.Item Effect of Photobiomodulation on Transforming Growth Factor-beta(1), Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study(MARY ANN LIEBERT, INC, 2016-01-01) Keskiner, Ilker; Lutfioglu, Muge; Aydogdu, Ahmet; Saygun, N. Isil; Serdar, Muhittin A.Objective: This study evaluated the impact of photobiomodulation (PBM) on the healing of the donor palatal area following free gingival graft (FGG) harvesting by examining changes in transforming growth factor (TGF)-beta(1), platelet-derived growth factor (PDGF)-BB, and interleukin (IL)-8 levels in palatal wound fluid (PWF). Material and methods: Thirty patients were selected and randomly assigned to receive PBM (laser group) or PBM sham (sham group) in the palatine area after FGG harvesting. Aneodymium-doped yttrium aluminumgarnet (Nd:YAG) laser (1064 nm) was applied to the test sites immediately after surgery and every 24 h thereafter for 4 days. PWF was collected on Days 7 and 12, and PWF TGF-beta(1), PDGF-BB, and IL-8 levels were analyzed by enzyme-linked immunosorbent assays (ELISA). Results: PWF TGF-beta(1), PDGF-BB, and IL-8 levels were significantly lower on Day 12 than on Day 7 for both groups. PWF TGF-beta(1), PDGF-BB, and IL-8 levels of the laser group were significantly higher than those of sham group on Day 7 (p < 0.05). PWF TGF-beta(1) levels were also significantly higher in laser group than in the sham group on Day 12Item Sample size, power and effect size revisited: simplified and practical approaches in pre-clinical, clinical and laboratory studies(CROATIAN SOC MEDICAL BIOCHEMISTRY \& LABORATORY MEDICINE, 2021-01-01) Serdar, Ceyhan Ceran; Cihan, Murat; Yucel, Dogan; Serdar, Muhittin A.Calculating the sample size in scientific studies is one of the critical issues as regards the scientific contribution of the study. The sample size critically affects the hypothesis and the study design, and there is no straightforward way of calculating the effective sample size for reaching an accurate conclusion. Use of a statistically incorrect sample size may lead to inadequate results in both clinical and laboratory studies as well as resulting in time loss, cost, and ethical problems. This review holds two main aims. The first aim is to explain the importance of sample size and its relationship to effect size (ES) and statistical significance. The second aim is to assist researchers planning to perform sample size estimations by suggesting and elucidating available alternative software, guidelines and references that will serve different scientific purposes.Item Two Cases of the Same Family with the Unusual Elevation of CA19-9 Levels(ORDEM MEDICOS, 2014-01-01) Uyanik, Metin; Sertoglu, Erdim; Serdar, Muhittin A.; Aydin, Fevzi N.; Ozgurtas, Taner; Kurt, IsmailIntroduction: Serum carbohydrate associated antigen (CA19-9) is widely used marker in clinical practice and shows small increases in a few benign diseases. Here we report two cases, a mother and her daughter with slightly elevated CA19-9 levels not accompanied by any clinical pathology. Case Presentation: The mother with elevated CA19-9 level (89.90 U/mLItem Investigation of the relationship between cord clamping time and risk of hyperbilirubinemia(TURKISH J PEDIATRICS, 2020-01-01) Yasartekin, Yuksel; Sarici, S. Umit; Ozcan, Murat; Akpinar, Melis; Altun, Demet; Akin, Agah; Serdar, Muhittin A.; Sarici, DilekBackground. Although the relationship between umbilical cord clamping time and various parameters such as hemoglobin (Hb) levels, iron deficiency, and risk of neonatal jaundice has previously been studied, to the best of our knowleadge there have been no studies investigating the relationship between cord clamping time and the risk of significant hyperbilirubinemia. We aimed to investigate the relationship between the time of umbilical cord clamping and transcutaneous bilirubin (TcB) measurements made on various postnatal hours, Hb and serum total bilirubin (STB) levels measured on postnatal 4th day, and the risk of development of significant hyperbilirubinemia requiring phototherapy treatment. Methods. Eligible newborns were divided into two groups on the basis of the time of cord clamping: those clamped late (60 seconds or moreItem Macro-aspartate aminotransferase (AST): a case report(WALTER DE GRUYTER GMBH, 2016-01-01) Can, Ummugulsum; Sayar, Ersin; Serdar, Muhittin A.Aspartate aminotransferase (AST) macroenzyme leads to an increase in AST without the presence of any disease. In present report, an isolated increase of AST was detected in a 6-year old girl following the investigations prior to tonsillectomy. As to her history, physical examination and other laboratory test results, no abnormal findings were detected. AST levels were measured as 591 IU/L and 585 IU/L after repeated tests. While found as <5.4 IU/L (recovery <0.8\%, reference interval 42.0-82.2\%) after polyethylene glycol (PEG) precipitation, AST was determined as 561 IU/L (recovery 95.4\%) as a result of the assessment performed with non-specific human antimouse antibodies (HAMA). No diseases were encountered in the patient, and reason for the increase of AST was considered to be macroAST. Because continuously increased enzyme value may lead to various invasive and expensive diagnostic tests, macroAST should be taken into account in the evaluation process.