Modified Local Linear Estimators in Partially Linear Additive Models with Right-Censored Data Based on Different Censorship Solution Techniques.

This paper introduces a modified local linear estimator (LLR) for partially linear additive models (PLAM) when the response variable is subject to random right-censoring. In the case of modeling right-censored data, PLAM offers a more flexible and realistic approach to the estimation procedure by involving multiple parametric and nonparametric components. This differs from the widely used partially linear models that feature a univariate nonparametric function.

Right-censored partially linear regression model with error in variables: application with carotid endarterectomy dataset.

This paper considers a partially linear regression model relating a right-censored response variable to predictors and an extra covariate with measured error. The main problem here is that censorship and measurement error problems need to be solved to estimate the model correctly. In this sense, we propose three modified semiparametric estimators obtained from local polynomial regression, kernel smoothing, and B-spline smoothing methods based on kernel deconvolution approach and synthetic data transformation.

Penalty and Shrinkage Strategies Based on Local Polynomials for Right-Censored Partially Linear Regression.

This study aims to propose modified semiparametric estimators based on six different penalty and shrinkage strategies for the estimation of a right-censored semiparametric regression model. In this context, the methods used to obtain the estimators are ridge, lasso, adaptive lasso, SCAD, MCP, and elasticnet penalty functions. The most important contribution that distinguishes this article from its peers is that it uses the local polynomial method as a smoothing method.

Right-Censored Time Series Modeling by Modified Semi-Parametric A-Spline Estimator.

This paper focuses on the adaptive spline (A-spline) fitting of the semiparametric regression model to time series data with right-censored observations. Typically, there are two main problems that need to be solved in such a case: dealing with censored data and obtaining a proper A-spline estimator for the components of the semiparametric model. The first problem is traditionally solved by the synthetic data approach based on the Kaplan-Meier estimator.

Comparison of parametric and semi-parametric models with randomly right-censored data by weighted estimators: Two applications in colon cancer and hepatocellular carcinoma datasets.

In this study, parametric and semi-parametric regression models are examined for random right censorship. The components of the aforementioned regression models are estimated with weights based on Cox and Kaplan-Meier estimates, which are semi-parametric and nonparametric methods used in survival analysis, respectively. The Tobit based on weights obtained from a Cox regression is handled as a parametric model instead of other parametric models requiring distribution assumptions such as exponential, Weibull, and gamma distributions.

Vieussens' arterial ring: a rare coronary variant anatomy.

Purpose: We aimed to evaluate Vieussens' arterial ring (VAR) variants by consecutive coronary computed tomography (CT) angiography examinations.

Methods: We retrospectively evaluated the presence of VAR in a total of 3443 consecutive coronary CT angiography examinations performed between November 2010 and January 2015. CT examinations were performed with a 64-row multidetector computed tomography (MDCT) scanner.

Low radiation dose computed tomography coronary angiography: evaluation of the variations in coronary arteries.

Objective: Despite attempts to decrease the radiation dose, coronary computed tomography angiography (CCTA) generally uses higher doses than computed tomography scans of other organs. The purpose of this study was to evaluate the incidence of the variations of the coronary arteries using the adaptive statistical iterative reconstruction technique to perform low-dose coronary computed tomography (CTA).

Methods: Diagnostic CCTA scans were performed in 3433 patients (from November 2010 to January 2015) using an Optima CT660 (GE Healthcare, USA) 64-slice and analyzed retrospectively.

Diagnosis of the left circumflex coronary artery fistula drainage into the left ventricle by echocardiographic color Doppler flow imaging.

Congenital coronary fistula is consisted of a communication between a coronary artery and a cardiac chamber or pulmonary vessel. Congenital left coronary artery-left ventricle fistula is uncommon. A 41-year-old female patient admitted to our institution for evaluation of heart murmur etiology.

Myocardial functional and textural findings of the right and left ventricles and their association with cellular adhesion molecules in Behçet's disease.

Aim: This study was designed to assess whether ultrasonic reflectivity, evaluated by integrated backscatter analysis was associated with the severity of inflammation and diastolic dysfunction of the left (LV) and right ventricles (RV) in Behçet's disease (BD).

Methods: The study consisted of 20 patients with BD and 18 healthy controls. The expression of CD11b and CD63 on the surface of granulocytes and monocytes were measured by flow cytometry.

N-terminal probrain natriuretic peptide predicts altered circadian variation in essential hypertension.

Diminished nocturnal blood pressure fall in nondipper hypertensive patients are closely associated with poor prognosis. N-terminal probrain natriuretic peptide can also identify poor prognosis in miscellaneous heart diseases. In this study, we aimed to clarify the association between probrain natriuretic peptide levels and diminished nocturnal blood pressure fall in patients with essential hypertension.

Predictors of atrial fibrillation after coronary artery bypass surgery.

Objective: Atrial fibrillation is one of the most common arrhythmias associated with not only increased morbidity after coronary artery bypass grafting but also increased healthcare costs. Many factors are associated with atrial fibrillation onset after coronary artery bypass grafting. We prospectively examined which factors could predict atrial fibrillation after coronary artery bypass grafting.

Effects of angiotensin-converting enzyme gene polymorphism and serum vitamin D levels on ambulatory blood pressure measurement and left ventricular mass in Turkish hypertensive population.

Introduction: Regulation of angiotensin converting enzyme (ACE) and angiotensin II (ang-II) levels is under genetic control. 1,25(OH)2 vitamin D3 treatment has been shown to reduce the ang-II level, reduce myocardial hypertrophy and to decrease blood pressure. This study was designed to examine the effect of ACE gene polymorphisms on 24-h ambulatory blood pressure measurement (24 h) values, vitamin D levels and target organ damage in hypertensive patients.

Myocardial ischemia caused by a coronary anomaly left anterior descending coronary artery arising from right sinus of Valsalva.

We present the case of a patient in anomalous origin of the left anterior descending coronary artery that caused myocardial ischemia and led to positive myocardial scintigraphic results. Coronary angiography showed that the left anterior descending coronary artery arose from the right coronary ostium-an anomaly that has been associated with chest discomfort-without atherosclerotic lesions. Left circumflex artery and the diagonal branches were arising from the left main coronary artery and the whole coronary tree were free of atherosclerosis.

Prediction of subclinical left ventricular dysfunction with strain rate imaging in patients with mild to moderate rheumatic mitral stenosis.

Background: Left ventricular (LV) long-axis function evaluated by Doppler tissue echocardiography-derived strain rate (SR) imaging has been shown to be a useful index of LV systolic function; however, it has not been evaluated in patients with mitral stenosis (MS). We examined the LV long-axis function of patients with pure MS and normal global systolic function as assessed by LV ejection fraction.

Method: In all, 30 patients (22 women; 45 +/- 9 years) with mild to moderate MS (mitral valve area = 1.

[Effects of beta-blockers on transmitral, pulmonary venous flows, and spontaneous echo-contrast grades in heart failure].

Objective: In this study, we aimed to investigate effects of metoprolol treatment on transmitral, pulmonary venous flows and spontaneous echo contrast in patients with heart failure.

Methods: Twenty-four patients (mean age: 55+/-8 years) with heart failure were enrolled to the study. All were given metoprolol succinate with titrated target dose of 50 mg/d controlled release tablets for 1 month.

Left ventricular diastolic function and circadian variation of blood pressure in essential hypertension.

The purpose of this prospective study was to determine the relationship between circadian blood pressure and left ventricular diastolic function in essential hypertension. The study population included 25 patients aged 56 +/- 18 years with non-dipper hypertension and 25 age- and sex-matched patients with dipper hypertension. They underwent conventional Doppler echocardiography and color tissue Doppler from apical 4- and 2-chamber views.

Myocardial Ischemia caused by a coronary anomaly: left circumflex coronary artery arising from right sinus of valsalva.

We present the case of a patient in whom a previously undetected anomalous origin of the circumflex coronary artery caused myocardial ischemia and led to positive myocardial scintigraphic results. Subsequent coronary angiography showed that the left circumflex coronary artery arose from the right coronary ostium-an anomaly that has been associated with chest discomfort-without atherosclerotic lesions. The peripheral distribution of the left circumflex artery was normal.

Effects of dipper and non-dipper status of essential hypertension on left atrial mechanical functions.

Aim: This study was designed in order to investigate the effects of dipper and non-dipper status of hypertension on left atrial mechanical (reservoir, conduit and booster pump) functions with left atrial volume measurements by means of two-dimensional echocardiography in untreated systemic hypertensive patients.

Method: A total of 27 untreated dipper hypertensive patients, group I (15 female, 12 male, mean age 57+/-12 years); 23 untreated non-dipper hypertensive patients, group II (12 female, 11 male, mean age: 53+/-18 years); and 25 voluntary healthy individuals, group III (13 female, 12 male, mean age 53+/-10 years) were included into the study. Twenty-four hour blood pressure (BP) measurement was performed by the cuff-oscillometric method to evaluate the nocturnal decrease of BP.