Association of endothelial nitric oxide synthase promoter region (T-786C) gene polymorphism with acute coronary syndrome and coronary heart disease

İstanbul Bilim Üniversitesi, Tıp Fakültesi.Background Nitric oxide (NO) is an endothelium derived relaxing factor (EDRF) which has an important role for regulating the heart-vessel physiology. The objective of this study was to evaluate the effects of the eNOS T-786C polymorphism on lipid parameters and the development of acute coronary syndrome (ACS) and coronary heart disease (CHD) for the first time in a Turkish study group. We have analyzed the genotype frequencies of the T-786C polymorphism of the eNOS gene in 10 ACS patients (5 men, 5 women), 20 CHD patients (14 men, 6 women), and 31 controls (10 men, 21 women), who were angiographically proven to have normal coronaries. Results The demographic, biochemical and left ventricule systolic dysfunction data of the ACS, CHD patients and controls were analyzed as a function of eNOS T-786C genotypes. The eNOS gene T-786C polymorphism frequencies for T/T, C/T and C/C genotypes were respectively 10%, 40%, 50% in subjects with ACS; 75%, 20%, 5% in subjects with CHD and 67.7%, 25.8%, 6.5% in the control group. Significant difference was observed in genotype frequencies between the study groups for T-786C polymorphism (p = 0.001). The CC genotype frequency was found to be the most prevalent in ACS group in comparison to CHD and control groups (p = 0.001). TT was the most frequently observed genotype in both CHD patients and controls (p = 0.001). Left ventricule systolic dysfunction frequency was found to be highest in C/T genotype carriers (66.7%) in patients (ACS+CHD). None of the patients with LVSD were carrying the normal genotype (T/T). The eNOS T-786C polymorphism was not found to be effective over any analyzed lipid variable in patients (ACS+CHD). The HDL-cholesterol levels were found to be lower in CHD group were compared to controls (p < 0.01), whereas glucose and leucocyte levels of the ACS and CHD groups were both higher than controls (p < 0.001). Conclusion The significantly high frequency of eNOS -786C/C genotype in ACS patients than in those of controls, indicate the genotype association with ACS. The finding of significantly high frequency of T/T genotype in the CHD group, may support the relationship of CC genotype with ACS without CHD. The high frequency of the mutant (C/C) and heterozygous (C/T) genotypes found may be linked to left ventricule remodeling after MI

Gas and seismicity within the Istanbul seismic gap

Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain

Mapping the Environmental Fitness Landscape of a Synthetic Gene Circuit

Gene expression actualizes the organismal phenotypes encoded within the genome in an environment-dependent manner. Among all encoded phenotypes, cell population growth rate (fitness) is perhaps the most important, since it determines how well-adapted a genotype is in various environments. Traditional biological measurement techniques have revealed the connection between the environment and fitness based on the gene expression mean. Yet, recently it became clear that cells with identical genomes exposed to the same environment can differ dramatically from the population average in their gene expression and division rate (individual fitness). For cell populations with bimodal gene expression, this difference is particularly pronounced, and may involve stochastic transitions between two cellular states that form distinct sub-populations. Currently it remains unclear how a cell population's growth rate and its subpopulation fractions emerge from the molecular-level kinetics of gene networks and the division rates of single cells. To address this question we developed and quantitatively characterized an inducible, bistable synthetic gene circuit controlling the expression of a bifunctional antibiotic resistance gene in Saccharomyces cerevisiae. Following fitness and fluorescence measurements in two distinct environments (inducer alone and antibiotic alone), we applied a computational approach to predict cell population fitness and subpopulation fractions in the combination of these environments based on stochastic cellular movement in gene expression space and fitness space. We found that knowing the fitness and nongenetic (cellular) memory associated with specific gene expression states were necessary for predicting the overall fitness of cell populations in combined environments. We validated these predictions experimentally and identified environmental conditions that defined a “sweet spot” of drug resistance. These findings may provide a roadmap for connecting the molecular-level kinetics of gene networks to cell population fitness in well-defined environments, and may have important implications for phenotypic variability of drug resistance in natural settings

Conjugate directions based order recursive implementation of post-Doppler adaptive target detectors

An implementation for the post-Doppler adaptive target detectors enabling an efficient change of the subspace dimension is described. The proposed implementation uses the order recursive structure of the conjugate directions method and does not present any additional computational burden on the processor. The implementation can be particularly useful for the adaptive detectors with an indeterminate number of auxiliary vectors for the clutter covariance matrix estimation. Through the proposed method, the subspace dimension can be easily increased or decreased according to the multiplicity of the auxiliary vectors at no loss of computational efficiency

Cerebral lateral ventricular asymmetry on CT: How much asymmetry is representing pathology?

Purpose: The purpose of this study was to evaluate the association of asymmetric lateral ventricle (ALV) with clinical and structural pathologies and assess its clinical importance. Materials and methods: We analyzed 170 consecutive ALV cases on computed tomography (CT) and 170 control group patients with normal head CT. Patients who had apparent etiologic causes for ALV were excluded. The differential diagnosis of ALV and unilateral hydrocephalus (UH) was made by using three different ventricle-brain ratios (VBRs). The measurements of the ALV were made at the frontal horn level. Patients with asymmetry were divided into three subgroups including mild, moderate and severe groups to eloborate the grade of the ventricular asymmetry. Additional CT findings including septal deviation, diffuse enlargement, atrophy and the densities of constant sites were also recorded systematically for each patient. Clinical and handedness data were collected and analyzed. Results: The prevalence of ALV in the study population was 6.1%. Headache was the most common reason for head CT examination and was significantly more common in the asymmetry group (61.7% in group A, 42.9% in group B, P = 0.001). Transient ischemic attack, focal neurologic findings, vertigo, ataxia, visual and hearing disturbances were similar in both groups (P > 0.5). There was no difference in smoking and alcohol habits in both patient groups. Ten (5.8%) patients in group A and 16 (9.4%) patients in group B had neuropsychiatric disorders, which did not achieve statistical significance. In group A patients, the larger ventricle was more common in the left side than in the right (left = 70.0%, right = 30.0%). Group A consisted of 57.0% mild (grade 1, n = 97), 26.5% moderate (grade II, n = 45) and 16.5% severe (grade III, n = 28) patients. There was no significant correlation between handedness and ALV. The density of different brain sites was found close similar on both sides in ALV and control group (P > 0.5). Choroidal cystic or solid neoplasm or periventricular dysplasia was detected in six ALV patients in group A (3.5%), on their additional MR examinations. Conclusion: The physician should not overlook an ALV finding on unenhanced CT, particularly in cases with severe degree of asymmetry or diffuse ventricular enlargement, and search for possible accompanying disorders. © Springer-Verlag 2008

Investigation of the Effect of Solidification Time and Addition Amount of Inoculation on Microstructure and Hardness in Lamellar Graphite Cast Iron

Material suppliers typically recommend different additive amounts and applications for foundry practices. Therefore, even in the production of the same standard materials, different results may be obtained from various production processes on different foundry floors. In this study, the liquid metal prepared with the addition of different proportions of a FeSi-based inoculation, which is most commonly used in foundries in the production of a cast iron material with EN-GJL-250 lamellar graphite cast iron, was cast into sand molds prepared with a model designed to provide different solidification times. In this way, the optimization of the inoculation amounts on the casting structure for different solidification times was investigated. In addition, hardness values were determined depending on solidification time in varying amounts of inoculation additions. SolidCast casting simulation software was used to determine the casting model geometry and solidification time. In the scope of the study, sand casting, modeling, microstructure analysis, image analysis, microstructure analysis, and hardness tests techniques were used. When the results are examined, the required amount of inoculation for the optimal structure is optimized for the application procedure depending on the casting module and the solidification time