Search

Aim of this study is to investigate the properties of mono-atomic gas flow through the porous medium by using Event-Driven Molecular Dynamics (EDMD) simulation in the transition regime. The molecules and the solid particles forming the porous structure were modelled as hard spheres hence molecule trajectories, collision partners, interaction times and post-collision velocities were calculated deterministically. The porous medium is formed of spherical particles suspended in the middle of the channel and these particles are distributed into the channel in a regular cubic array. Collisions of gas molecules with porous medium were provided by means of the specular reflection boundary condition. A negative pressure boundary condition was applied to the inlet and outlet of the porous media to ensure gas flow. Porosity, solid sphere diameter and Knudsen number (Kn) were initially input to the simulation for different Cases. Thus, the effects of these parameters on mass flow rate, dynamic viscosity, tortuosity and permeability were calculated by EDMD simulation. The results were compared with the literature and were found to be consistent. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Endothelial dysfunction is recognized as an early and initiating event in the pathogenesis of coronary artery disease. Gene polymorphisms of endothelial constitutive nitric oxide synthase (ecNOS), angiotensin converting enzyme (ACE) and angiotensin II type 1 receptor (AT1R) have been found to be associated with atherosclerosis. We aimed to investigate the possible effects of ecNOS, ACE and AT1R gene polymorphisms on endothelial functions in healthy population. MATERIALS AND METHODS: In 255 healthy subjects (male/ female: 119/136 mean age 35.1±2.3 years) ecNOS, ACE and AT1R gene polymorphisms were assessed by polymerase chain reaction (PCR). Endothelium dependent (EDD, flow-mediated) and endothelium independent vasodilation (EID) were measured by high resolution brachial artery ultrasound and 0.5mg sublingual nitroglycerine respectively. RESULTS: ecNOS and ACE genes had no significant effect on EDD and EID. However, subjects with AT1RAC+CC genotypes had lower EDD compared to subjects with AT1RAA genotype in females (19.4 ± 6.6% vs 21.5 ± 7.8%, p = 0.041). EDD and EID were significantly negatively associated with age, body mass index, serum creatinine, glucose, uric acid and hemoglobin levels.When the data on age, uric acid, BMI, glucose, creatinine, and hemoglobin were split into 3 as low-1/3, mid-1/3 and high 1/3, there was significant graded decrease in EDD and EID with these parameters. In multiple regression analysis, age and presence of AT1RAC+CC genotype retained as significant independent factors predicting endothelial functions. CONCLUSIONS: Gene polymorphisms of endothelial constitutive nitric oxide synthase and angiotensin converting enzyme had no effect on endothelial functions. However, the presence of angiotensin II type 1 receptor polymorhism (AT1RAC+CC genotype) seemed to adversely affect the endothelial functions as reflected by impaired endothelium dependent and independent vasodilatation in healthy individuals. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Dermatology / Turk Dermatoloji Dergisis is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: P-wave dispersion (Pd), corrected P-wave dispersion (Pdc), QT-wave dispersion (QTd), and corrected QT-wave dispersion (QTdc) parameters were not assessed in Turner Syndrome (TS) before. The aim of this study is to investigate the cardiac arrhythmogenic potential in patients with TS. Methods: Thirty-one patients with TS and 30 healthy women were enrolled in the study. For this purpose 12-lead electrocardiogram (ECG) and 24-hour ambulatory ECG recordings were performed. Results: Pd, Pdc, QTd, and QTdc were significantly higher in patients with TS. On 24-hour ambulatory ECG recording, the mean heart rate (HR) was higher, while the mean of all RR intervals between normal beats (MeanNN), the standard deviation of all the RR intervals (SDNN), the square root of the mean of the squared differences of two consecutive RR intervals (rMSSD), and the percentage of the beats with consecutive RR interval difference more than 50 milliseconds (pNN50) were lower in TS. Conclusion: There were significant increases in Pd, Pdc, QTd, and QTdc in patients with TS and they may be features of the disease. The frequency of supraventricular arrhythmias was increased. There also was a significant deterioration of sympathetic and parasympathetic components of autonomic function as assessed by heart rate variability (HRV) in Turner patients. [ABSTRACT FROM AUTHOR]

Background: Growth hormone deficiency (GHD) is known to cause higher rates of cardiovascular mortality. The purpose of the study was to analyze the structural and functional changes in the heart and investigate their relation to autonomic function as assessed with heart rate variability (HRV).Methods: Eleven untreated GHD patients (mean age 50.4 +/- 10.7 years, M/F: 3/8) and 15 age- and sex-matched healthy persons (mean age 45.3 +/- 10.4 years, M/F: 5/10) were compared. Both groups were examined with echocardiography, HRV, and exercise testing and findings were analyzed.Results: The groups were similar in height, weight, body mass index, body surface area, systolic and diastolic blood pressure, heart rate. The GHD patients had lower exercise duration and metabolic equivalent (MET) compared to controls (7.94 +/- 1.26 vs. 9.8 +/- 1.9 min, P < 0.001, for MET 8.85 +/- 0.86 vs. 10.7 +/- 2.23, P = 0.03). On echocardiography, GHD patients had lower interventricular septum diastolic diameter (9 +/- 0.89 vs. 10.7 +/- 0.88 mm, P < 0.001) and posterior wall thickness (8.4 +/- 0.93 vs. 9.8 +/- 0.91 mm, P = 0.002), and lower left ventricle mass index (90.9 +/- 20 vs. 112 +/- 8 g/m2, P = 0.01). Left ventricular ejection fraction was lower in the GHD patients (57.4 +/- 5.12% vs. 65.5 +/- 4.1%, P < 0.001). Time and frequency domain heart rate variability parameters, SDNN, SDANN, VLF, LF ve LF/HF were lower in GHD patients compared to controls. There was a significant correlation between left ventricle diastolic diameter and LF (r = 0.62, P = 0.02).Conclusion: GHD seemed to cause decreased left ventricle mass and decreases in the sympathetic components of HRV that may have a bearing on the increased cardiovascular risk seen in these patients. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of the Valsalva maneuver on P-wave durations and dispersion. After the Valsalva maneuver, we found that maximum P-wave duration increased, minimum P-wave duration decreased, and P-wave dispersion increased in controls, whereas the opposite was true for unselected patients with paroxysmal AF. It was concluded that patients with paroxysmal AF performing the Valsalva maneuver normalized their P-wave dispersion, thereby correcting the inhomogeneous intra-atrial conduction. [ABSTRACT FROM AUTHOR]

In this cross-sectional, controlled study, Helicobacter pylori (H. pylori) infection, a probable factor in the development of gastrointestinal problems, was investigated in dialysis patients and renal transplant recipients. Forty-seven dialysis patients (22 male, 25 female, mean age of 36.6±15 yr (range 18–83 yr)), 57 renal transplant recipients (39 male, 18 female, mean age of 36.8±10 yr (range 19–60 yr)) and 55 healthy individuals (34 male, 21 female, mean age of 33.4±9.6 yr (range 21–58 yr)) were included and no significant difference was found in the study groups. The mean time spent on dialysis in the hemodialysis group was 32.5±27.7 months (range 1–100 months). H. pylori antibodies were detected in 22 of 57 (38.6%) patients in the transplantation group, 31 of 47 (65.9%) patients in the dialysis group and 39 of 55 (72.5%) in the control group. No correlation was found between H. pylori infection and age, sex, primary disease, frequency of dialysis, duration and type of transplantation and the immunosuppressive therapy. However, patients with H. pylori antibodies spent a shorter time on dialysis compared to patients without the antibodies (26.6±23.5 vs 44.1±32.1 months, p=0.038). The frequency of H. pylori infection in the transplantation group was significantly lower than the control and dialysis groups (p<0.01). This finding may be explained on the basis of decreased humoral antibody response to H. pylori infection, secondary to immunosuppressive therapy rather than decreased incidence of infection in the transplantation group. Finally, we concluded that the value of the serological test for diagnosis of H. pylori infection should be interpreted cautiously in these patient groups. [ABSTRACT FROM AUTHOR]

Copyright of Zeitschrift für Kinderheilkunde is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Arterial stiffness is a strong predictor of mortality in hemodialysis patients. In this study, we aimed to investigate possible relations of arterial stiffness with volume status determined by bioimpedance analysis and aortic blood pressure parameters. Also, effects of a single hemodialysis session on these parameters were studied., Methods: A total of 75 hemodialysis patients (M/F: 43/32; mean age: 53 ± 17) were enrolled. Carotid-femoral pulse wave velocity, augmentation index, and aortic pulse pressure were measured by applanation tonometry before and after hemodialysis. Extracellular fluid and total body fluid volumes were determined by bioimpedance analysis., Results: Carotid-femoral pulse wave velocity (9.30 ± 3.30 vs 7.59 ± 2.66 m/s, p < 0.001), augmentation index (24.52 ± 9.42 vs 20.28 ± 10.19, p < 0.001), and aortic pulse pressure (38 ± 14 vs 29 ± 8 mmHg, p < 0.001) significantly decreased after hemodialysis. Pre-dialysis carotid-femoral pulse wave velocity was associated with age (r 2  = 0.15, p = 0.01), total cholesterol (r 2  = 0.06, p = 0.02), peripheral mean blood pressure (r 2  = 0.10, p = 0.005), aortic-mean blood pressure (r 2  = 0.06, p = 0.02), aortic pulse pressure (r 2  = 0.14, p = 0.001), and extracellular fluid/total body fluid (r 2  = 0.30, p < 0.0001). Pre-dialysis augmentation index was associated with total cholesterol (r 2  = 0.06, p = 0,02), aortic-mean blood pressure (r 2  = 0.16, p < 0.001), and aortic pulse pressure (r 2  = 0.22, p < 0.001). Δcarotid-femoral pulse wave velocity was associated with Δaortic-mean blood pressure (r 2  = 0.06, p = 0.02) and inversely correlated with baseline carotid-femoral pulse wave velocity (r 2  = 0.29, p < 0.001). Pre-dialysis Δaugmentation index was significantly associated with Δaortic-mean blood pressure (r 2  = 0.09, p = 0.009) and Δaortic pulse pressure (r 2  = 0.06, p = 0.03) and inversely associated with baseline augmentation index (r 2  = 0.14, p = 0.001). In multiple linear regression analysis (adjusted R 2  = 0.46, p < 0.001) to determine the factors predicting Log carotid-femoral pulse wave velocity, extracellular fluid/total body fluid and peripheral mean blood pressure significantly predicted Log carotid-femoral pulse wave velocity (p = 0.001 and p = 0.006, respectively)., Conclusion: Carotid-femoral pulse wave velocity, augmentation index, and aortic pulse pressure significantly decreased after hemodialysis. Arterial stiffness was associated with both peripheral and aortic blood pressure. Furthermore, reduction in arterial stiffness parameters was related to reduction in aortic blood pressure. Pre-dialysis carotid-femoral pulse wave velocity was associated with volume status determined by bioimpedance analysis. Volume control may improve not only the aortic blood pressure measurements but also arterial stiffness in hemodialysis patients.

Objectives: Exocrine pancreatic dysfunction may contribute to malnutrition and lack of appetite in the advanced stages of heart failure. Nutritional assessment was carried out on patients diagnosed with mild or moderate/severe heart failure. Fecal elastase levels are an indicator of pancreatic exocrine function and ghrelin is an appetite hormone which is also investigated for its contribution to malnutrition., Study Design: This is an observational study. 52 patients (32 males, 20 females) aged over eighteen years and hospitalized for acute decompensated heart failure (ADHF) were included in the study. They were compared with 31 people (16 male, 15 female) of the same age as Control Group (C). Patients in New York Heart Association (NYHA) stages 1 and 2 were grouped as mild (miADHF), while those in NYHA stages 3 and 4 were grouped as moderate/severe ADHF (seADHF). Fecal and blood samples were taken at admission. In ADHF patients, exocrine pancreatic functions and their relationship with malnutrition were evaluated. Statistical analyses were performed using Tukey's test, the independent-sample t-test, the Kruskal-Wallis test, the Mann-Whitney U-test, the chi-square test and Pearson's bivariate correlation analysis., Results: Significantly decreased fecal elastase levels were found when moderate/severe ADHF patients and the control group were compared. (C 278.9±144.8, miADHF 336.6±181.7, seADHF 168.7±153.6, p=0.002). 10 seADHF patients (50%) had severe, 4 (20%) moderate, and 6 (30%) mild pancreatic insufficiency. Ghrelin levels were higher in seADHF patients compared to C and miADHF patients (C 69.7±34.6, miCHF 82.5±48.2, SeADHF 105.0±78.1 p=0.361)., Conclusion: Fecal elastase and ghrelin hormone levels can contribute to the determination of malnutrition in ADHF patients.