Browsing by Author "Aycan, Zehra"

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Early Subclinical Left-Ventricular Dysfunction in Obese Nonhypertensive Children: a Tissue Doppler Imaging Study
(Springer, 2013) Kibar, Ayse Esin; Pac, Feyza Aysenur; Balli, Sevket; Oflaz, Mehmet Burhan; Ece, Ibrahim; Bas, Veysel Nejat; Aycan, Zehra
A direct effect of obesity on myocardial function has not been not well established. Our aim was to investigate the effect of body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR) on left-ventricular (LV) myocardial function in normotensive overweight and obese children by tissue Doppler imaging (TDI). We calculated the mitral annular displacement index (DI) and myocardial performance index (MPI) using TDI indices of systolic and diastolic LV function. In this hospital-based, prospective cross-sectional study, we studied 60 obese (mean age 13.2 +/- A 2.0 years) and 50 normal children. Subjects were divided into three groups: group 1 (BMI < 25, n = 50, control), group 2 (BMI 25-29.9 kg/m(2), n = 30, overweight), and group 3 (BMI a parts per thousand yen 30 kg/m(2), n = 30, morbidly obese). Standard echocardiography showed increased LV diameters and LV mass/index and preserved ejection fraction in obese children. By TDI, LV systolic and diastolic function showed that peak late myocardial velocity (Em = 15.4 +/- A 2 cm/s), peak early myocardial velocity (Am = 8.7 +/- A 1.3 cm/s), Em/Am ratio (1.8 +/- A 0.3), isovolumetric relaxation time (IVRT = 59.2 +/- A 8.2 ms), MPI (0.39 +/- A 0.03), and DI (25.5 +/- A 3.2 %) of the lateral mitral annulus in the obese subgroups were significantly different from those of control subjects (18.2 +/- A 1.2 cm/sn, 6.9 +/- A 0.6 cm/sn, 2.6 +/- A 0.2, 51.2 +/- A 9.6 ms, 0.34 +/- A 0.03, and 33.13 +/- A 5.0 %, respectively; p < 0.001). These structural and functional abnormalities were significantly related to BMI. There were positive correlations between HOMA-IR, septal MPI, and LV mass. DI and MPI data indicated impaired subclinical LV function in all grades of isolated obesity at a preclinical stage. Insulin resistance and BMI correlated significantly with indices of LV function.
Effect of Obesity on Left Ventricular Longitudinal Myocardial Strain by Speckle Tracking Echocardiography in Children and Adolescents
(Galenos Publ House, 2015) Kibar, Ayse Esin; Pac, Feyza Aysenur; Ece, Ibrahim; Oflaz, Mehmet Burhan; Balli, Sevket; Bas, Veysel Nejat; Aycan, Zehra
Background: Impaired subclinical ventricular function may contribute to the risk of cardiovascular disease in obesity. Aims: The aim of this study was to determine the influence of obesity on left ventricular (LV) longitudinal myocardial function in normotensive obese children using two-dimensional (2D) speckle tracking echocardiography (STE). Study Design: Case-control study. Methods: Sixty normotensive obese children aged 1016 years (mean age, 13.9 +/- 2.3 years) were compared with 50 normal-weight controls. Obese participants had a body mass index (BMI)>= 95th percentile. Regional strain/strain rate (SR) values were compared with left ventricular (LV) parameters. The correlation was studied by linear regression analysis. Results: Obese subjects exhibited a significantly higher LV end-diastolic diameter, left atrium/aortic diameter ratio, and LV mass/index when compared to controls (p<0.001). Left ventricular ejection fraction and regional systolic myocardial velocities were similar in the obese and control groups. By 2D STE, regional strain of both the septal wall (average strain: -16.0 +/- 3.9% vs-21.9 +/- 2.4%, p<0.001) and lateral wall (average strain: -15.6 +/- 2.3% vs -22.9 +/- 3.5%, p<0.001); regional SR of both the septal wall (average SRsys: -0.7 +/- 0.22 s(-1) vs -1.3 +/- 0.32 s(-1), p<0.001) and lateral wall (average SRsys: -0.67 +/- 0.19 s(-1) vs-1.33 +/- 0.31 s(-1), p<0.001); regional SR E/A of both the septal wall (average SR E/A : 1.8 +/- 0.83 vs. 2.2 +/- 0.91, p: 0.004) and lateral wall (average SR E/A : 1.4 +/- 0.43 vs. 2.4 +/- 1.21, p<0.001); and global strain (-14.6 +/- 7.34% vs -20.9 +/- 3.24%, p<0.001) were lower in the obese group compared with the controls. These strain imaging parameters appear to be related to the severity of obesity and can contribute to increased BMI. Left ventricular mass was found to be correlated with a decrease in global LV strain. Conclusion: Our study showed that childhood obesity is associated with an alteration in the longitudinal LV function. Segmental analysis of the LV can provide subtle markers for the emergence of future obesity-related cardiac disease.
Novel Tshr Mutations in Consanguineous Families With Congenital Nongoitrous Hypothyroidism
(Wiley, 2010) Cangul, Hakan; Morgan, Neil V.; Forman, Julia R.; Saglam, Halil; Aycan, Zehra; Yakut, Tahsin; Maher, Eamonn R.
Objective Nonsyndromic autosomal recessively inherited non-goitrous congenital hypothyroidism (CHNG) can be caused by mutations in TSHR, PAX8, TSHB and NKX2-5. We aimed to investigate mutational frequencies of these genes and genotype/phenotype correlations in consanguineous families with CHNG. Design Because consanguinity in individuals with a presumptive genetic condition is often an indicator of an autosomal recessive inheritance and allows firmer correlations to be established between genotype and phenotype, we planned to execute our study in consanguineous families. Patients Hundred and thirty-nine children with CHNG phenotype born to consanguineous families. Measurements First, we investigated cases for evidence of linkage to the four known CHNG genes by microsatellite marker analysis. Mutation analysis by direct sequencing was then performed in those cases in whom linkage to the relevant candidate gene could not be excluded. In addition, in silico analysis of the predicted structural effects of TSHR mutations was performed and related to the mutation-specific disease phenotype. Results Homozygous germline TSHR mutations were detected in six families (5%), but no mutations were detected in PAX8, TSHB and NKX2-5. Four of TSHR mutations had not previously been described. Genotype-phenotype correlations were established and found to be related to the predicted structural effects of the mutations. Conclusions Known causative genes account for the development of CHNG only in a minority of cases, and our cohort should provide a powerful resource to identify novel causative genes and to delineate the extent of locus heterogeneity in autosomal recessively inherited CHNG.
Tshr Is the Main Causative Locus in Autosomal Recessively Inherited Thyroid Dysgenesis
(Walter de Gruyter Gmbh, 2012) Cangul, Hakan; Aycan, Zehra; Saglam, Halil; Forman, Julia R.; Cetinkaya, Semra; Tarim, Omer; Maher, Eamonn R.
Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder and results in mental retardation if untreated. Eighty-five percent of CH cases are due to disruptions in thyroid organogenesis and are mostly sporadic, but about 2% of thyroid dysgenesis is familial, indicating the involvement of genetic factors in the aetiology of the disease. In this study, we aimed to investigate the Mendelian (single-gene) causes of non-syndromic and non-goitrous congenital hypothyroidism (CHNG) in consanguineous or multicase families. Here we report the results of the second part (n=105) of our large cohort (n=244), representing the largest such cohort in the literature, and interpret the overall results of the whole cohort. Additionally, 50 sporadic cases with thyroid dysgenesis and 400 unaffected control subjects were included in the study. In familial cases, first, we performed potential linkage analysis of four known genes causing CHNG (TSHR, PAX8, TSHB, and NKX2-5) using microsatellite markers and then examined the presence of mutations in these genes by direct sequencing. In addition, in silico analyses of the predicted structural effects of TSHR mutations were performed and related to the mutation specific disease phenotype. We detected eight new TSHR mutations and a PAX8 mutation but no mutations in TSHB and NKX2-5. None of the biallelic TSHR mutations detected in familial cases were present in the cohort of 50 sporadic cases. Genotype/phenotype relationships were established between TSHR mutations and resulting clinical presentations. Here we conclude that TSHR mutations are the main detectable cause of autosomal recessively inherited thyroid dysgenesis. We also outline a new genetic testing strategy for the investigation of suspected autosomal recessive non-goitrous CH.