Browsing by Subject "Clinical feature"
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Item Open Access Application of the RIMARC algorithm to a large data set of action potentials and clinical parameters for risk prediction of atrial fibrillation(Springer, 2015) Ravens, U.; Katircioglu-Öztürk, D.; Wettwer, E.; Christ, T.; Dobrev, D.; Voigt, N.; Poulet, C.; Loose, S.; Simon, J.; Stein, A.; Matschke, K.; Knaut, M.; Oto, E.; Oto, A.; Güvenir, H. A.Ex vivo recorded action potentials (APs) in human right atrial tissue from patients in sinus rhythm (SR) or atrial fibrillation (AF) display a characteristic spike-and-dome or triangular shape, respectively, but variability is huge within each rhythm group. The aim of our study was to apply the machine-learning algorithm ranking instances by maximizing the area under the ROC curve (RIMARC) to a large data set of 480 APs combined with retrospectively collected general clinical parameters and to test whether the rules learned by the RIMARC algorithm can be used for accurately classifying the preoperative rhythm status. APs were included from 221 SR and 158 AF patients. During a learning phase, the RIMARC algorithm established a ranking order of 62 features by predictive value for SR or AF. The model was then challenged with an additional test set of features from 28 patients in whom rhythm status was blinded. The accuracy of the risk prediction for AF by the model was very good (0.93) when all features were used. Without the seven AP features, accuracy still reached 0.71. In conclusion, we have shown that training the machine-learning algorithm RIMARC with an experimental and clinical data set allows predicting a classification in a test data set with high accuracy. In a clinical setting, this approach may prove useful for finding hypothesis-generating associations between different parameters.Item Open Access MEFV gene is a probable susceptibility gene for Behçet's disease(Taylor & Francis, 2005) Imirzalıoglu, N.; Dursun, A.; Tastan, B.; Soysal, Y.; Yakıcıer, M. C.Objective: Behçet's disease (BD) is a rare, chronic, multisystem inflammatory disorder. The prevalence of BD is higher in the Middle Eastern and Mediterranean populations. Another chronic inflammatory disease, familial Mediterranean fever (FMF), is also known to be highly prevalent in these populations. The prevalence of BD is higher in the FMF patient population than in populations known to be rich in BD. Both BD and FMF have some pathophysiological features in common and they result from inappropriate activation of neutrophils. Clinical manifestations of both diseases can mimic each other and the coexistence of both diseases in the same patient has been reported. Given that BD and FMF have similar pathophysiological, epidemiological, and clinical features, we hypothesized that the gene responsible for FMF, MEFV, may also play a role in the pathogenesis of BD. Methods: Forty-two BD patients who had no symptoms and family history for FMF and 66 healthy controls were screened for common MEFV gene mutations (E148Q, M680I, M694V, and V726A). Results: Fifteen patients (36%) displayed MEFV mutations (nine M694V, five E148Q, and one M680I) and mutation rates were significantly elevated compared to 66 (11%) healthy controls (p=0.0034). Conclusion: The occurrence of frequent MEFV mutations in BD patients suggests that the MEFV gene is involved in the pathogenesis of Behçet's disease. © 2005 Taylor & Francis.Item Open Access Skewed X-chromosome inactivation in scleroderma(Springer New York, 2008) Uz, E.; Loubiere, L. S.; Gadi, V. K.; Ozbalkan, Z.; Stewart, J.; Nelson, J. L.; Ozcelik, T.Scleroderma is a female-prevalent autoimmune disease of unclear etiology. Two fundamental gender differences, skewed X-chromosome inactivation (XCI) and pregnancy-related microchimerism, have been implicated in scleroderma. We investigated the XCI patterns of female scleroderma patients and the parental origin of the inactive X chromosome in those patients having skewed XCI patterns (>80%). In addition, we investigated whether a correlation exists between XCI patterns and microchimerism in a well-characterized cohort. About 195 female scleroderma patients and 160 female controls were analyzed for the androgen receptor locus to assess XCI patterns in the DNA extracted from peripheral blood cells. Skewed XCI was observed in 67 (44.9%) of 149 informative patients and in 10 of 124 healthy controls (8.0%) [odds ratio (OR) = 9.3 (95% confidence interval (CI) 4.3-20.6, P < 0.0001)]. Extremely skewed XCI (>90%) was present in 44 of 149 patients (29.5%) but only in 3 of 124 controls (2.4%; OR = 16.9; 95% CI 4.8-70.4, P < 0.0001). Parental origin of the inactive X chromosome was investigated for ten patients for whom maternal DNA was informative, and the inactive X chromosome was of maternal origin in eight patients and of paternal origin in two patients. Skewed XCI mosaicism could be considered as an important risk factor in scleroderma.Item Open Access Somatic mosaicism for a MECP2 mutation associated with classic Rett syndrome in a boy(Nature Publishing, 2002) Topçu, M.; Akyerli, C.; Sayi, A.; Törüner, G. A.; Koçoǧlu, S. R.; Cimbiş, M.; Özçelik, T.Rett syndrome is a severe neurodevelopmental disorder that arises from mutations in the X-linked MECP2 gene. It is almost exclusively seen in girls due to the predominant occurrence of the mutations on the paternal X-chromosome, and also the early postnatal lethal effect of the disease causing mutations in hemizygous boys. We identified a boy with features of classic Rett syndrome who is mosaic for the truncating MECP2 mutation R270X. Chromosome analysis showed normal karyotype. These results indicate that a MECP2 mutation associated with Rett syndrome in females could lead to a similar phenotype in males as a result of somatic mosaicism.Item Open Access X chromosome inactivation and female predisposition to autoimmunity(Springer New York, 2008) Ozcelik, T.[No abstract available]