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H-type hypertension (HHT) is closely associated with cardiovascular and cerebrovascular complications, as well as peripheral vascular sclerosis. However, the mechanism underlying the relationship between HHT and cardiac remodeling is not completely clear. Therefore, this study aimed to investigate the structural differences in a cardiac ultrasound between patients with HHT and those with non-H-type hypertension (NHHT). This study was performed on 300 elderly patients ($\ge 60$ years) with essential hypertension and stratified into two groups based on their homocysteine (Hcy) levels: 150 with HHT and 150 with NHHT. The cardiac structure was assessed using color Doppler echocardiography. The key parameters were measured, including interventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular mass index (LVMI), and others. The chi-square test was employed to examine the differences in cardiac ultrasound outcomes between HHT and NHHT groups. Left ventricular hypertrophy (LVH) was observed in 118 patients (78.7%) in the HHT group and 75 patients (50.0%) in the NHHT group. The HHT group demonstrated a significantly higher prevalence of LVH (${\chi }^2=5.183$, $p<0.0001$). Patients with HHT had significantly higher systolic blood pressure, Hcy levels, LVPWT, IVST, and LVMI compared with those with NHHT: systolic blood pressure ($165.2\pm 13.15$ mm Hg versus $148.6\pm 11.06$ mm Hg), Hcy ($15.36\pm 3.15\mu$mol/L versus $8.15\pm 3.12$  $\mu$mol/L), LVPWT ($12.5\pm 1.16$ mm versus $10.2\pm 1.22$ mm), IVST ($13.6\pm 1.25$ mm versus $11.2\pm 1.15$ mm), and LVMI ($121.3\pm 22.15$ g/m² versus $110.5\pm 23.36$ g/m²). The correlation analysis showed a notable positive relationship between Hcy levels and LVMI ($r=0.386$, $p<0.001$), and between systolic blood pressure and LVMI ($r=0.536$, $p<0.001$). The occurrence of LVH was notably greater in patients with HHT than in those with NHHT. Furthermore, Hcy and systolic blood pressure levels were positively correlated with LVMI.

Transmitral flow velocity pattern obtained by pulsed Doppler technique reflects left ventricular (LV)diastolic function, but an increase in left atrial pressure pseudo-normalizes the flow pattern and masks diastolic dysfunction. Flow propagation velocity (FPV) measured, using color M-mode Doppler and baseline-shift technique, represents an average velocity of early diastolic LV filling flow from mitral orifice to mid-ventricle. In patients with ischemic heart disease and dilated cardiomyopathy, including those with pseudonormalized transmitral flow pattern, FPV had good correlation with the time constant of early diastolic LV pressure decay (Tau), indicating that FPV is a useful noninvasive diastolic-function parameter which does not pseudo-normalize. Unlike the conventional Doppler parameters, FPV was well correlated with Tau in patients with hypertrophic cardiomyopathy, and was distinctly decreased even in hypertensive patents without LV hypertrophy. Thus, FPV is a unique noninvasive diastolic parameter, which can sensitively and accurately detect LV diastolic impairment.

In a pilot study on the effect of decreased baroreflex sensitivity in well-trained long distance speedskaters we showed that directly after the contest period the sensitivity was significantly decreased. One month later, the sensitivity increased to almost normal values. In the first week after the contest period, 4 of the 9 speedskaters showed (pre)syncope behavior in a tilt table experiment. This was seen several minutes after tilting, in ongoing decrease of bloodpressure even until 50 mmHg, while heart rate was paradoxically further decreased. After 2 weeks, this behavior disappeared. We attributed this decreased sensitivity and syncope incidents to the increased vagal activity in rest as found in these athletes.

It is well known that the right vagal nerve mainly influences the rhythmogenesis of the SA-node, while the left branch predominantly influences the conductivity of the AV-node. These effects will be amplified in the case of well-trained physical condition. In a study on the changes in baroreflex sensitivity, we compared the effect of acute increase in arterial bloodpressure in rats by phenylephrine infusion in cases of unilateral vagotomy. We showed that in cases of right vagotomy, with only the left vagal branch intact, the PQ interval increases 5 to 10 times more than in cases of left vagotomy. Also, in the right vagotomy cases, much more AV-blocking was found. These results suggest that in cases of predominantly left vagal nerve activity on heart rate control, increased vagal activity induces heart rate irregularities, while under normal conditions no irregularities were observed.

The acute increase in pressure only increases vagal activity acutely, so after ten to twenty seconds the heart rate is normal again. Therefore we studied the effect of right vagotomy in endurance trained rats. For this study we used 20 rats with both vagal nerves intact: 10 sedentary for control and 10 were trained at 80% of maximal VO2 during 6 months, (BV-rats), and 20 rats in which the right vagal nerve was cut: 10 sedentary and 10 trained (RV-rats). Weekly ECG's were recorded about 5 hours after training. In the BV-rats, heart rate decreased significantly compared to control after 2 weeks, stabilizing at about 20% lower after 5 weeks. In the RV-rats, it took 5 weeks before they had a significantly lower heart rate, and after 7 weeks they stabilized at about 10% lower heart rate. All rats except one, had PQ intervals between 40 and 55 ms during the experiment. In several RV-rats, irregularities in AV conduction were seen. In one RV-rat, the PQ interval was increased directly after vagotomy from 45 to 65 ms. In the fourth week this rat died suddenly during a recording session. The AV conduction changed from first degree block to complete block. Ventricular rate was decreased progressively from 300 beats/min to about 150. After 1 minutes the rat was reanimated. In the period hereafter no other "sudden death" was observed, although it is well possible that in the absence of the investigator also this sudden death pattern occurs, which than was interrupted by life saving activity of the sympathatic nerves system.

This study showed that in case of predominantly control of the heart by the left vagal branch, under increased vagal activity due to training or acute increase in arterial pressure, sudden death can occur under normal physiological conditions, due to the decreased sensitivity of the baroreflex.

The arterial wall dynamics evaluation requires the assessment of its frequency-response. The aim was to apply an original methodology, to evaluate the arterial wall pressure-diameter frequency-response and elastic complex modulus, of human in vivo and in vitro common carotid arteries (CCA). CCA pressure, diameter and wall thickness were recorded. In vitro recordings were performed using pressure microtransducer (Konigsberg) and sonomicrometry, in 14 CCA segments (from donors). The in vivo recordings were obtained non-invasively by tonometry and mode-B echography in 10 normotensive patients, and in 10 hypertensive patients before and after 3 months of treatment with an ACE-inhibitor. A system modeling-identification approach was used to estimate the viscoelastic parameters: elastic, viscous and inertial indexes, and to perform an isofrequency analysis (up to 5Hz) of the incremental elastic modulus E_inc(jω) of the arterial wall. The new approach, proposed to evaluate the frequency-dependence of arterial wall mechanics, was applied satisfactorily.

The mechanics of cerebral aneurysm pathogenesis, evolution and rupture are not yet well understood. This paper presents a numerical analysis of the formation of a saccular cerebral aneurysm in for the first time in a 3D model of the basilar artery bifurcation under normal and hypertensive blood pressure. Due to the excessive endothelium derived nitric oxide produced in high wall shear stress, we assumed that smooth muscle cell relaxation is the origin of the aneurysm formation. Arterial wall remodeling under constant tension was considered to be the other mechanism of disease evolution. The wall was constructed from two elastic and hyperelastic isotropic regions. The flow was considered steady, laminar, Newtonian, and incompressible. The fully coupled fluid and structure models were solved with the finite elements package ADINA 8.5. The wall shear stress, effective stress and deformation distributions under normal and hypertensive blood pressure were compared to a healthy bifurcation. The model shows that although the malfunction of the endothelial cell layer and the corresponding smooth muscle cell-related loss of vascular tone is important to the inception of the disease; A saccular aneurysm may not be formed by this mechanism alone, and also requires the fiber-related arterial wall remodeling for further development.

Diabetes mellitus (DM) or hyperglycemia (in a more generalized term, high blood sugar) is a metabolic disorder that is now highly prevalent in the world population. Most of the food that people consume is converted into glucose, which enters the bloodstream following absorption–assimilation mechanisms. As a natural process, cells in our body utilize glucose for growth and energy. The glucose balance is maintained by a hormone called insulin that is secreted by the beta cells of pancreas. Hypotheses at the backdrop of DM occurrence are either (i) enough insulin is not produced and secreted resulting in increased level of glucose in blood, or (ii) insulin is insensitive to glucose, or (iii) insulin is non-targeted etc. If DM remains uncontrolled over time, it leads to serious damage to many of the body's systems, especially the nerves and blood vessels. This paper develops an enquiry into diabetes from many angles: (i) Diabetes as a disorder, its complications, causes, diagnostic tests, and treatment; (ii) Analysis of retinal and plantar images to characterize diabetes complications; (iii) How analysis of heart rate variability signals can depict diabetes; (iv) Biomedical engineering of the glucose–insulin regulatory system, and its employment in the modeling of the oral glucose tolerance test data, to detect diabetes as well as persons at risk of being diabetic; (v) Application of the glucose–insulin regulatory system to formulate an insulin delivery system for controlling blood sugar.

The risk of rupture of intracranial saccular aneurysms is one of the leading dilemmas for patients and neurologists. Although the probability of rupture is small, the consequences of rupture are usually fatal or crippling, and a concern for the patient is whether or not to treat an existing aneurysm. In this paper, an idealized model of saccular aneurysms with assumed Fung material behavior was investigated for rupture potential when the stresses exceeded the maximum wall strength of the aneurysm wall. Numerical simulations used various levels of blood pressure, from normal to hypertensive, in order to determine correlations of aneurysm size and risk of rupture. Results showed that hypertensive individuals harboring cerebral aneurysms with a size of at least 6 mm are at risk.

Fluid–structure interaction (FSI) simulations were carried out in a human cerebral aneurysm model with the objective of quantifying the effects of hypertension and pressure gradient on the behavior of fluid and solid mechanics. Six FSI simulations were conducted using a hyperelastic Mooney–Rivlin model. Important differences in wall shear stress (WSS), wall displacements, and effective von Mises stress are reported. The hypertension increases wall stress and displacements in the aneurysm region; however, the effects of hypertension on the hemodynamics in the aneurysm region were small. The pressure gradient affects the WSS in the aneurysm and also the displacement and wall stress on the aneurysm. Maximum wall stress with hypertension in the range of rupture strength was found.

The analysis of gene expression data using existing methods and tools has become a fundamental approach for researchers to explore the mechanisms of hypertension. However, many researchers lack programming skills or statistical knowledge. Although gene expression data is widely available, they originate from various experiments with different standards and quality levels, causing inconvenience to researchers. While tools and databases with interactive interfaces exist for data analysis, they may have limited applicability. This study aimed to construct High Blood Pressure Gene Expression Omnibus (HBPGEO), a program based on the R Shiny platform. It integrated the discovery of differentially expressed genes, hub gene identification, gene function analysis, and more. It allowed users to select suitable methods and set different parameters during analysis, visualize results interactively, and download the analyzed results. The study successfully utilized HBPGEO to identify hypertension-related biomarkers.