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Publication Open Access Effectiveness of posterior structures in the development of proximal junctional kyphosis following posterior instrumentation: a biomechanical study in a sheep spine model(Elsevier, 2019) Akgül, Turgut; Sarıyılmaz, Kerim; Özkunt, Okan; Dikici, Fatih; Yazıcıoğlu, Önder; N/A; Korkmaz, Murat; Doctor; School of MedicineIntroduction: proximal junctional kyphosis – PJK has been defined by a 10 or greater increase in kyphosis at the proximal junction as measured by the Cobb angle from the caudal endplate of the uppermost instrumented vertebrae (UIV) to the cephalad endplate of the vertebrae 1 segments cranial to the UIV. In this biomechanical study, it is aimed to evaluate effects of interspinosus ligament complex distruption and facet joint degeneration on PJK development. Materials and methods: posterior instrumentation applied between T2 – T7 vertebrae using pedicle screws to randomly selected 21 sheeps, divided into 3 groups. First group selected as control group (CG), of which posterior soft tissue and facet joints are protected. In second group (spinosus group, SG) interspinosus ligament complex which 1 segment cranial to UIV has been transected, and third group (faset group-FG) was applied facet joint excision. 25 N, 50 N, 100 N, 150 N and 200 N forces applied at frequency of 5 Hertz as 100 cycles axial to the samples. Then, 250 N, 275 N and 300 N forces applied static axially. Interspinosus distance, kyphosis angle and discus heights was measured in radiological evaluation. Abnormal PJK was defined by a proximal junctional angle greater than 100 and at least 100 greater than the corresponding preoperative measurement. Results: in CG group, average interspinosus distance was 6,6 ± 1.54 mm and kyphosis angle was 2,2 ± 0.46° before biomechanical testing, and they were measured as 9,4 ± 1.21 mm and 3,3 ±0.44° respectively after forces applied to samples. In SG group, average interspinosus distance was 6,2 ± 1.72 mm and kyphosis angle was 2,7 ± 1.01° before experiment, and they were measured as 20,8 ± 5.66 mm and 15,1 ± 2.34° respectively after forces applied to samples. In FG group, average interspinosus distance was 4,8 ± 1.15 mm and kyphosis angle was −1 ± 4.14° before experiment, and they were measured as 11,1 ±1.96mm and 11 ± 2.87° respectively after forces applied to samples. In comparison to group CG, statistically significant junctional kyphosis was seen on both FG and SG group after statistical analysis. (p < 0.05). PJK was seen statistically significant more on SG group than FG group. (p < 0.05). Not any statistically significant difference was seen on measurement of disk distances among three groups. (p > 0.05) Conclusions: protecting interspinosus ligament complex and facet joint unity during posterior surgical treatment for spine deformation is vital to prevent PJK development. Based on our literature review, this is the first biomechanical study that reveals interspinosus ligament complex are more effective on preventing PJK development than facet joints.Publication Open Access Random assignment under weak preferences(Elsevier, 2009) Department of Economics; Department of Economics; Yılmaz, Özgür; Faculty Member; College of Administrative Sciences and Economics; 108638The natural preference domain for many practical settings of the assignment problems is the one in which agents are allowed to be indifferent between objects, the weak preference domain. Most of the existing work on assignment problems assumes strict preferences. There are important exceptions. but they provide solutions only to the assignment problems with a social endowment, where agents own objects collectively and there are no private endowments. We consider the general class of assignment problems with private endowments and a social endowment. Our main contribution is a recursive solution for the weak preference domain. Our solution satisfies individual rationality, ordinal efficiency and a recently introduced fairness axiom, no justified-envy.Publication Open Access The epidemiological and molecular characterization of vancomycin-resistant enterococci Isolated from rectal swab samples of hospitalized patients in Turkey(Clinical Laboratory, 2014) Çakırlar, Fatma Köksal; Karakullukçu, Asiye; Sirekbasan, Serhat; Bağdatlı, Yaşar; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Barış, İbrahim; Kavaklı, İbrahim Halil; Teaching Faculty; College of Engineering; 111629; 40319Background: Vancomycin-resistant enterococci (VRE) are a serious problem all over the world. The present study was conducted to investigate antimicrobial resistance patterns, genotypes, clonal relationship, and virulence factors of VRE species isolated from rectal swab samples of hospitalized patients, patient's relatives, and medical staff at Istanbul University Cerrahpasa Medical School hospital. Methods: The VRE isolates were typed with an automated VITEK system and their antibiotic sensibilities were analysed by disc diffusion and Etest (R) method. The molecular characterization and clonal relationships were performed using a PCR method and virulence genes by sequence typing. Results: A total of 100 (10.3%) of the 971 patients were colonized with VRE. None of the investigated 25 patient's relatives and 45 medical staff carried VRE. All VRE strains were identified as E. faecium. They were vanA geno-type and originated from a single clone. VRE strains exhibited multi-drug resistance. High-level gentamicin-resistance was 93%. However, lower resistance rates were found for linezolid (40%) and quinopristin-dalfopristin (11%). The enterococcal surface protein gene esp was found positive in 87 of 100 isolates, and four strains were positive for the cylB (cytolysin) gene. Conclusions: The identification of VRE strains to the species level and detection of virulence genes will assist in infection control practices.Publication Open Access Rosiglitazone-induced changes in the oxidative stress metabolism and fatty acid composition in relation with trace element status in the primary adipocytes(Sciendo, 2019) N/A; Aydemir, Duygu; Sarayloo, Ehsan; Ulusu, Nuriye Nuray; PhD Student; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; N/A; N/A; 6807Metabolic syndrome, obesity and type 2 diabetes are metabolic disorders characterized by the insulin resistance and the impairment in the insulin secretion. Since impairment in the oxidative stress and adipocyte metabolism contribute to the formation of obesity and diabetes, targeting adipose tissue can be considered as an effective approach to fight against them. Rosiglitazone is used for treatment for patients with type 2 diabetes via inducing lipogenesis and transdifferentiation of white adipose tissue into brown adipose tissue. Since the development of such therapeutics is required to control the formation and function of brown fat cells, we aimed to reveal possible molecular mechanisms behind rosiglitazone induced biochemical changes in the adipose tissue. Cells were expanded in the adipocyte culture medium supplemented with 5 μg/mL insulin following 2 days' induction. After those cells were treated with rosiglitazone 0, 0.1 3 mol/L and 10 μmol/L rosiglitazone for 48 hours and at 8th day, cells were collected and stored at -80 °C. Then the cells were used to evaluate antioxidant enzyme activities, mineral and trace element levels and fatty acid composition. Glucose-6-phosphate dehydrogenase and glutathione reductase significantly reduced in rosiglitazone-treated groups compared to the control. Na, Mg, K, Ca, Cr, Fe, Ni, Cu, Zn, Rb, Sr, Cs, Ba and Pb were determined in the cell lysates via ICP-MS. Also, relative FAME content decreased in the rosiglitazone-treated groups compared to the control. Rosiglitazone treatment at low doses showed promising results which may promote brown adipose tissue formation.Publication Open Access The probabilistic serial mechanism with private endowments(Elsevier, 2010) Department of Economics; Department of Economics; Yılmaz, Özgür; Faculty Member; College of Administrative Sciences and Economics; 108638A random assignment is ordinally efficient if it is not stochastically dominated with respect to individual preferences over sure objects. When there are no private endowments, the set of ordinally efficient random assignments is characterized by the eating algorithm (Bogomolnaia and Moulin, 2001). When there are private endowments, the main requirement is individual rationality; however, the eating algorithm fails to deliver this property. Our contribution is the natural generalization of the eating algorithm for this general class of problems. The family of this generalized eating algorithm characterizes the set of individually rational and ordinally efficient random assignments. A special solution in this family, the individually rational probabilistic serial (PS(IR)), also achieves a new fairness axiom, no justified-envy. However, it is not immune to strategic manipulation. We show that individual rationality, no justified-envy and strategy-proofness are incompatible.Publication Open Access Predicting mortality in patients with spontaneous bacterial peritonitis using routine inflammatory and biochemical markers(Lippincott Williams and Wilkins (LWW), 2018) Iliaz, Raim; Özpolat, Tahsin; Demir, Kadir; Kaymakoğlu, Sabahattin; Beşışık, Fatih; Akyüz, Filiz; Baran, Bülent; Faculty Member; Koç University Hospital; 167583Objectives: Spontaneous bacterial peritonitis (SBP) is a common and high-mortality infectious complication of patients with cirrhosis. New inflammatory markers are associated with morbidity/mortality in various diseases. The aim of our study was to find the 30-day mortality rate of SBP and their predictors. Patients and methods: Seventy patients with cirrhosis complicated with SBP and 55 non-SBP controls were enrolled into the study, and patients were evaluated for mortality rate and its predictors. Results: The 30-day and 3-month mortality rates in the SBP group were 26.1 and 50.7%, respectively. Mortality rates were higher in the SBP group than in the controls. Symptoms at hospital admission and cell counts in ascitic fluid made no difference in predicting 30-day mortality. Patients with SBP with high serum neutrophil counts, high neutrophil-lymphocyte ratio, high C reactive protein (CRP)/albumin ratio, and high model for end-stage liver disease (MELD) score had higher 30-day mortality rates. We determined optimal cutoff values of MELD scores and serum neutrophil counts for predicting 30-day mortality as 20.5 and 6850/mm(3), respectively. The sensitivity and specificity for the MELD cutoff value were 83.3 and 80.4%, respectively. We also followed up patients for 60 months after SBP; the patients with high inflammatory markers and MELD scores at the time of SBP diagnosis had worse survival compared with the group with lower levels. Conclusion: Our results suggest that SBP has high 30-day mortality. MELD scores and inflammatory markers (CRP, CRP albumin ratio, neutrophil-lymphocyte ratio) may be used to predict mortality in patients with SBP.Publication Open Access Long-term prognosis of commercially sexually exploited youth in Turkey: brief report(Anadolu Psikiyatri Dergisi - Anatolian Journal of Psychiatry, 2017) Semerci, B.; Tufan, A. E.; Sanli, I.; N/A; Taşkıran, Ali Sarper; Other; School of Medicine; 195168Objective: Factors contribute to commercial sexual exploitation of youth (CSEY) and a variety of physical and psychological consequences of CSEY were previously discussed in the literature. The aim of the current study was to determine the long term prognosis of a sample of CSEY in Turkey. Methods: A sample of 108 CSEY (all females) with a mean age of 16.7 +/- 2.7 (range: 9-22) years living in a specialized center for protection against perpetrators were examined in terms of their sociodemographic variables, previous abuse history, family history and current psychopathology. Identified cases were referred for psychiatric evaluation. We obtained follow-up data 11 years after initial contact from this cohort (mean age 25.9 +/- 2.6 at time of follow-up) with the subjects and received information regarding their current functioning. Results: Follow up data revealed that recommendations during psychiatric follow up could not be acted upon. 71.4% of the initial sample (n= 76) could be reached via direct or indirect contacts. We found that good/superior functioning was very rare and that one-third of the sample that could be reached still was being sexually exploited. Important considerations derived from the results were discussed in the current article.Publication Open Access Homozygous, and compound heterozygous mutation in 3 turkish family with jervell and lange-nielsen syndrome: case reports(BioMed Central, 2017) Uysal, F.; Turkgenc, B.; Toksoy, G.; Bostan, O. M.; Evke, E.; Uyguner, O.; Yakicier, C.; Cil, E.; Temel, S. G.; N/A; Kayserili, Hülya; Faculty Member; School of Medicine; 7945Background: Jervell and Lange-Nielsen syndrome (JLNS) isa recessive model of long QT syndrome which might also be related to possible hearing loss. Although the syndrome has been demonstrated to be originated from homozygous or compound heterozygous mutations in either the KCNQ1 or KCNE1 genes, additional mutations in other genetic loci should be considered, particularly in malignant course patients. Case presentations: Three patients were admitted into hospital due to recurrent seizures/syncope, intrauterine and postnatal bradycardia respectively; moreover all three patients had congenital sensorineural hearing-loss. Their electrocardiograms showed markedly prolonged QT interval. Implantable defibrillator was implanted and left cardiac sympathetic denervation was performed due to the progressive disease in case 1. She had countless ventricular fibrillation and appropriate shock while using an implantable defibrillator. The DNA sequencing analysis of the KCNQ1 gene disclosed a homozygous c.728G > A (p.Arg243His) missense mutation in case1. Further targeted next generation sequencing of cardiac panel comprising 68 gene revealed a heterozygous c.1346 T > G (p.Ile449Arg) variant in RYR2 gene and a heterozygous c.809G > A (p.Cys270Tyr) variant in NKX2-5 gene in the same patient. Additional gene alterations in RYR2 and NKX2-5 genes were thought to be responsible for progressive and malignant course of the disease. As a result of DNA sequencing analysis of KCNQ1 and KCNE1 genes, a compound heterozygosity for two mutations had been detected in KCNQ1 gene in case 2: a maternally derived c.477 + 1G > A splice site mutation and a paternally derived c.520C > T (p.Arg174Cys) missense mutation. Sanger sequencing of KCNQ1 and KCNE1 genes displayed a homozygous c.1097G > A (p.Arg366Gln) mutation in KCNQ1 gene in case 3. beta-blocker therapy was initiated to all the index subjects. Conclusions: Three families of JLNS who presented with long QT and deafness and who carry homozygous, or compound heterozygous mutation in KCNQ1 gene were presented in this report. It was emphasized that broad targeted cardiac panels may be useful to predict the outcome especially in patients with unexplained phenotype-genotype correlation. Clinical presentations and molecular findings will be discussed further to clarify the phenotype genotype associations.Publication Open Access Dimerization of pyrrole(TÜBİTAK, 1998) Yurtsever, Mine; Department of Chemistry; Department of Chemistry; Yurtsever, İsmail Ersin; Faculty Member; College of Sciences; 7129Accurate ab-inito quantum mechanical calculations of pyrrole dimers are reported. The thermodynamical stabilities of dimers with alpha - alpha, alpha -beta, and beta - beta type linkages are compared in order to predict the possibilities of branching in polypyrroles. Calculations employing large basis sets and including electron correlation effects predict the alpha - alpha dimers as the most stable form. However, an alpha - beta type bonding requires only 1.5-2.0 kcal/mol, and the energy necessary to introduce a beta - beta type bond is 3.6-4.0 kcal/mol. These values show that a high degree of branching is possible even at room temperatures.Publication Open Access Clinical presentation in a series of eight children with abdominal tuberculosis: experience of a single-center in Turkey(Kowsar Publishing Corporation, 2017) Usta, Merve; Urgancı, Nafiye; Dalgıç, Nazan; Kurtaraner, Tuğce; Karadağ, Çetin Ali; N/A; Kızılkan, Nuray Uslu; Faculty Member; School of MedicineBackground: Abdominal tuberculosis, the sixth commonest extrapulmanory tuberculosis, is easily misdiagnosed due to nonspecific gastrointestinal symptoms. The diagnosis is highly dependent on clinician's suspicion of the disease; therefore to increase awareness we retrospectively reviewed clinical features of eight children in a four year-period. Methods: The medical records of children with abdominal TB were retrospectively reviewed. The diagnosis of abdominal TB was defined as Mycobacterium tuberculosis infection of gastrointestinal tract along with peritoneal or solid organ involvement. Results: There were six girls and two boys with a mean age of 13.6 +/- 2.8 years (range, 7 - 16 years). Abdominal pain and weight loss were common complaints in all patients (100%) at presentation; fever was present in four (50%) patients and abdominal distension in two (25%) patients. Mean duration of symptoms before diagnosis was 2.5 +/- 1 months. Laparotomy performed in six patients, and the peritoneum was the most common infection site (in 5 patients). Chest X-rays of 7 patients indicated lung involvement. The most common abdominal computed tomography and ultrasonography finding was ascites. Bowel wall thickening was recorded in 2 patients and ileal thickening in 1 patient. Inguinal lymphadenopathy and multiple mesenteric lymphadenitis were present as single cases. Conclusions: The abdominal tuberculosis should be suspected in children with ongoing abdominal pain, fever, and abdominal distension, laparoscopy or laparotomy could be useful in the differential diagnosis and utilizing imaging techniques, invasive methods with clinical suspicion may prevent delay of the diagnosis.