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Results 701 - 750 of 1844
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Kim Eun-Joo - - 2004
To investigate the safety pharmacology of a novel fluoroquinolone antibiotic agent, DW-224a, on the vital functions, we studied its effects on the central nervous system, cardiovascular system and respiratory system. To determine the effects on the central nervous system, we used a modified Irwin's test at each time point after ...
Farah Vera M A - - 2004
There is evidence that alterations in heart rate and blood pressure variability (BPV) are associated with cardiovascular disease. We used a mice model to investigate the effects of acute and chronic stress on blood pressure variability (BPV) and heat rate variability (HRV). Shaker stress was given acutely (5 min, 150 ...
Cooke William H - - 2005
The purpose of this study was to test the hypothesis that high-intensity strength training increases vagal-cardiac control and cardiovagal baroreflex sensitivity. Twenty-two subjects [age 22 (0.8) years] were assigned to either strength training (ST, n=12) or control (CON, n=10) groups. Subjects in the ST group trained each major muscle group ...
Stemper B - - 2004
OBJECTIVE: To assess the possible abnormalities in the baroreflex modulation of both the heart and the arterial vasculature, in order to better evaluate the role of baroreflex abnormalities in the generation of the cardiovascular symptoms and complications affecting the familial dysautonomia (FD) patient. METHODS: Twenty-one FD patients and 22 controls ...
Cogliati Chiara - - 2004
BACKGROUND: The possible mechanisms by which beta-adrenergic antagonists may act on the neural regulation of the cardiovascular system are still elusive. Recent studies reported a marked increase of postganglionic muscle sympathetic nerve activity (MSNA) after acute beta-blockade associated with unchanged values of arterial blood pressure and baroreflex sensitivity. We tested ...
Rassi D - - 2005
BACKGROUND AND AIM: A fuller understanding of the neural control mechanisms of heart rate during the early stages of human development would be of great value to obstetric and neonatal management. In this paper, we investigate the correlation between heart rate variability (HRV) and other physiological parameters such as blood ...
Randall David C - - 2005
This study quantified the effect of interrupting the descending input to the sympathetic preganglionic neurons on the dynamic behavior of arterial blood pressure (BP) in the unanesthetized rat. BP was recorded for approximately 4-h intervals in six rats in the neurally intact state and in the same animals after complete ...
Lenard Zsuzsanna - - 2004
BACKGROUND: Cardiovagal autonomic control declines with age in adult subjects, which is related in part to increasing stiffness of the barosensory vessel wall. It is not known, however, whether autonomic function changes with age in children. METHODS AND RESULTS: We studied 137 healthy subjects divided into 4 age groups: group ...
Tulppo Mikko P - - 2005
The amplitude of low-frequency (LF) oscillations of heart rate (HR) usually reflects the magnitude of sympathetic activity, but during some conditions, e.g., physical exercise, high sympathetic activity results in a paradoxical decrease of LF oscillations of HR. We tested the hypothesis that this phenomenon may result from a feedback inhibition ...
Andriessen Peter - - 2004
To study cardiovascular autonomic control, we assessed the effect of atropine on heart rate (HR) and blood pressure (BP) variability in 12 preterm infants (range 26-32 wk) before intubation for respiratory insufficiency. Spectral power analysis of R-R interval and systolic BP (SBP) series were estimated in a low-frequency (LF; 0.04-0.15 ...
Stecyk Jonathan A W - - 2004
Like most vertebrates, humans die within minutes when deprived of molecular oxygen (anoxia), in part because of cardiac failure. In contrast, some freshwater turtles can survive anoxia for months at low temperatures, but to do so, they drastically suppress cardiac activity and autonomic cardiovascular control. Although Carassius carassius, the crucian ...
Reims Henrik M - - 2004
OBJECTIVES: We hypothesized that insulin sensitivity and vagal cardiac control are independently related in young men after adjustment for fitness and other confounding variables. DESIGN: Male volunteers aged 21-24 years with high (borderline hypertensive; n = 20) and low-normal (normotensive; n = 21) screening blood pressure (BP) were studied cross-sectionally. ...
Desai Nagaraj - - 2004
BACKGROUND: Congestive cardiac failure is associated with increased sympathetic activity and impaired baroreflex function. We sought to test the hypothesis that these patients also have blunted response of beat-to-beat QT interval variability during orthostatic challenge. METHODS: We compared beat-to-beat heart rate and QT interval data in 17 patients with congestive ...
Haley Robert W - - 2004
PURPOSE: To test the hypothesis that subtle abnormalities of the autonomic nervous system underlie the chronic symptoms reported by many Gulf War veterans, such as chronic diarrhea, dizziness, fatigue, and sexual dysfunction. METHODS: Twenty-two ill Gulf War veterans and 19 age-, sex-, and education-matched control veterans underwent measurement of circadian ...
Tanaka M - - 2004
BACKGROUND: Spontaneous baroreflex method allows continuous assessment of cardiovagal reflex function within resting blood pressure, but effects of nitrous oxide, per se, on the spontaneous baroreflex response remain unknown. This study was designed to determine the effects of nitrous oxide on spontaneous baroreflex gain and heart rate variability assessed by ...
Mitsutake Gen - - 2004
The aim of this study was to determine whether an artificial magnetic field with an amplitude and frequency equivalent to those of geomagnetic pulsations during geomagnetic storms could affect physiology and psychology. Three healthy volunteers wore anambulatory BP monitor and an ECG recorder around the clock for 12 consecutive weekends ...
Müller J - - 2004
The present study has been designed to investigate physiological effects of short (15 min) exposure to low level energy microwaves (< 10 microW cm(-2)). To this end heart rate, PQ, QS and ST (electrocardiography), respiration (conductive stretch band around the thorax), skin temperature (thermocouple), skin conductance (Ag/AgCl electrodes), systolic and ...
del Paso Gustavo A Reyes - - 2004
Baroreceptor sensitivity (BRS) is considered a powerful prognostic factor in cardiovascular health. This study investigated the possibility of modifying the baroreflex cardiac function through biofeedback. Thirty-two psychology students underwent 3 biofeedback sessions, with four 5-min trials each, in which they had to increase and decrease baroreflex function. BRS was assessed ...
Tanaka Makoto - - 2004
A high level of neuroaxial block may produce profound bradycardia and hypotension, possibly as a result of an imbalance between sympathetic and parasympathetic control of heart rate. We designed this study to test the hypothesis that cervical epidural anesthesia would increase the high-frequency (HF) component of heart rate variability (HRV) ...
Sakakibara R - - 2004
A 64 year-old woman developed Raynaud's phenomenon and dry eyes/mouth. Laboratory examination revealed positive Schirmer's test, rheumatoid factor and anti-nuclear antibody, and lymphocytic sialoadenitis on salivary gland biopsy. These features strongly suggested the diagnosis of primary Sjogren's syndrome. Three years later, she gradually developed generalized autonomic failure without apparent sensory ...
Marques-Neves C - - 2004
PURPOSE: Intraocular pressure (IOP) is a measure of the balance between the inflow and outflow of the aqueous humor, being in close relationship with the venous ocular blood flow. But the influence of the autonomic nervous system upon this variable is not well understood. One of the most frequently used ...
Grassi Guido - - 2004
OBJECTIVE: To determine whether in hypertension and in heart failure the occurrence of ventricular arrhythmias is associated with alterations in sympathetic drive and baroreflex function. DESIGN AND METHODS: We studied 28 untreated essential hypertensives (age, 53.0 +/- 1.1 years, mean +/- standard error of the mean), 15 without and 13 ...
Hallstrom Alfred P - - 2004
Decreased left ventricular ejection fraction is the most commonly used risk factor for identification of patients at high-risk for lethal ventricular arrhythmic events. Twenty-four-hour electrocardiographic (ECG) approaches to risk stratification include: counts of ventricular premature contractions (VPCs), measures of heart rate variability (HRV), and heart rate turbulence (HRT) which has ...
Nishikimi Toshio - - 2004
BACKGROUND: In the final step of production of adrenomedullin (AM), an inactive intermediate form of glycine-extended AM (AM-glycine) is converted to the active mature form of adrenomedullin (AM-mature) by enzymatic amidation. Recent studies have revealed that AM-mature and AM-glycine circulate in human plasma. In this study, we investigated the differences ...
Forsén A - - 2004
AIMS: Prospective studies of autonomic nerve function are rare. We have followed the progression of autonomic dysfunction in relation to nephropathy over 14 years in Type 1 diabetic patients. METHODS: Autonomic nerve function was assessed by heart-rate responses to deep breathing (E/I ratio) and tilting (acceleration and brake indices) and ...
Lucini Daniela - - 2004
BACKGROUND: Chronic orthostatic intolerance (COI) is a common and disabling autonomic syndrome of unclear pathophysiology. We tested the hypothesis that baroreflex and autonomic responses to graded lower body suction (LBNP, up to -40 mmHg) could be altered in COI patients. METHODS: Electrocardiogram (ECG), non-invasive arterial blood pressure and respiratory activity ...
Talpalar Adolfo E - - 2004
High pressure (>1.0 MPa) induces the high-pressure neurological syndrome (HPNS) characterized by increased excitability of the CNS and cognitive impairments involving memory disorders. The perforant-path transfer of cortical information to the hippocampal formation is important for memory acquisition. High pressure may alter information transfer in this connection. We used rat ...
Hamner J W - - 2004
We set out to fully examine the frequency domain relationship between arterial pressure and cerebral blood flow. Oscillatory lower body negative pressure (OLBNP) was used to create consistent blood pressure oscillations of varying frequency and amplitude to rigorously test for a frequency- and/or amplitude-dependent relationship between arterial pressure and cerebral ...
Iwasaki Ken-Ichi - - 2004
Adaptation to spaceflight or head-down-tilt bed rest leads to hypovolemia and an apparent abnormality of baroreflex regulation of cardiac period. In a previous study, we demonstrated that both chronic (2 wk) head-down-tilt bed rest and acute induced hypovolemia led to similar impairments in spontaneous baroreflex control of cardiac period, suggesting ...
Chapuis Bruno - - 2004
The objective of the present study was to examine whether a simple linear feedback model of arterial pressure (AP) control by the sympathetic nervous system would be able to reproduce the characteristic features of normal AP variability by using AP and renal sympathetic nerve activity (RSNA) data collected in conscious ...
Eitzen Ingrid - - 2004
OBJECTIVES: To discuss the methodologic challenges related to pressure mapping in seating and to present a new approach to the analysis and interpretation of results: the frequency analysis approach. DESIGN: Pressure mapping was performed on 3 prototypes of a newly developed foam and gel seat cushion. SETTING: Data collection was ...
Landén Mikael - - 2004
Measuring heart rate variability (HRV) is a way to assess the autonomic regulation of the heart. Decreased HRV, indicating reduced parasympathetic tone, has previously been found in depression and anxiety disorders. The objective of this study was to assess HRV in women with premenstrual dysphoric disorder (PMDD). To this end, ...
Deschamps Alain - - 2004
BACKGROUND: Epidurals are effective in relieving labor pain but result in a sympathectomy that may compromise maternal hemodynamic stability and fetal perfusion. Decreases in blood pressure and heart rate can be corrected, but markers of autonomic activity would be useful to predict and prevent such changes. The goal of this ...
Sahin I. - - 2004
Background: Many studies have shown that autonomic activation is one of the major factors in the etiology of hypertension. Furthermore, sympathovagal imbalance may be responsible for arrhythmias and sudden cardiac death. The aim of the present study was to compare and to evaluate the effects of short-term therapy with amlodipine ...
Penttilä J - - 2004
1 This double-blind, cross-over, placebo-controlled study on six healthy male volunteers was designed to evaluate the effects of alpha2-adrenoceptor antagonism on cardiac parasympathetic regulation. 2 The subjects received atipamezole intravenously as a three-step infusion, which aimed at steady-state serum concentrations of 10, 30 and 90 ng ml(-1) at 50-min intervals. ...
Westerhof Berend E - - 2004
OBJECTIVE: To test a new method (cross-correlation baroreflex sensitivity, xBRS) for the computation of time-domain baroreflex sensitivity on spontaneous blood pressure and heart interval variability using the EUROBAVAR data set. METHODS: We applied xBRS to the 42 records in the EUROBAVAR data set, obtained from 21 patients in the lying ...
Bouhaddi Malika - - 2004
Loss of autonomic cardiovascular homoeostasis is often suspected in hypertension that has developed after organ transplantation. We serially assessed autonomic cardiovascular control in eight patients in generally good condition who needed cyclosporine (CyA) treatment because of high risk of rejection in corneal transplantation. To this aim, we investigated the patients, ...
Bartels Matthew N - - 2004
Wide variations in respiratory rate and hypoxic stimulation of chemoreceptors may produce unreliable autonomic results in patients with COPD. We studied the reproducibility of two consecutive measurements of heart rate variability (HRV) and blood pressure variability (BPV) by time frequency analysis in patients with COPD while controlling respiratory rate and ...
Souza Neto Edmundo P - - 2004
This study investigated patients undergoing elective cardiac surgery to evaluate the effects of cardiopulmonary bypass (CPB) on the spontaneous variability of mean arterial pressure (MAP) and heart rate (HR). Forty-one adult patients receiving different cardiovascular system drugs were included in the study. Patients were divided into three groups: no preoperative ...
Tanaka M - - 2004
BACKGROUND: In conscious humans, men have a greater cardiovagal baroreflex gain than women. We studied gender-related differences in baroreflex function during general anaesthesia. METHODS: Sixty healthy patients (30 male and 30 female) were anaesthetized with sevoflurane 2% end-tidal in air and oxygen, and their lungs were mechanically ventilated. We recorded ...
Fathizadeh Payman - - 2004
OBJECTIVE: To evaluate the effects of sympathetic and parasympathetic nervous system activity on the heart rate and other hemodynamic variables in acute emergency patients with mild to moderately severe trauma. DESIGN: Clinical study. SETTING: Level 1 university-run trauma service. PATIENTS: Fourteen trauma patients studied immediately after admission to the emergency ...
Penttilä Jani - - 2004
We evaluated the cardiovascular effects of intravenously (i.v.) and buccally administered dexmedetomidine, a selective alpha2-adrenoceptor agonist. Six healthy male subjects were studied unmedicated and after 2 micro g/kg i.v. or buccal doses of dexmedetomidine, using repeated recordings of ECG and blood pressure. Cardiac parasympathetic activity was estimated by measurements of ...
Allan Louise - - 2004
Defaecation syncope is defined as blacking out at, or around, the time of defaecation. It is associated with increased mortality; however, patients rarely voluntarily report symptoms. We have examined autonomic function in a cohort of patients with defaecation syncope. METHODS: We prospectively identified all subjects referred to our unit with ...
Altieri Paolo - - 2004
BACKGROUND: The objective of the study was to compare the convective treatment modes, on-line hemofiltration (HF) and on-line hemodiafiltration (HDF), regarding cardiovascular tolerance and effects on blood pressure, when applied under similar conditions in stable dialysis patients. METHODS: 39 clinically stable dialysis patients were treated with HD for 6 months ...
Minami Junichi - - 2004
We assessed ambulatory blood pressure and heart rate variability in two female patients with pheochromocytoma. The ambulatory blood pressure and ECG R-R intervals were measured during a 24-h period with a portable recorder before and 3 weeks after surgery. A power-spectral analysis of R-R intervals was performed to obtain the ...
Alijani A - - 2004
BACKGROUND: This study hypothesized that patients in whom bradycardia and hypotension develop with induction of positive-pressure capnoperitoneum have an underlying autonomic cardiovascular dysfunction. METHODS: A case-control study was conducted to examine the baseline autonomic function of patients in whom bradycardia and hypotension develop with induction of positive-pressure capnoperitoneum. The control ...
Fletcher Janine - - 2004
OBJECTIVES: We have examined the acute effects (<45 min) of aldosterone antagonism on heart rate variability and baroreflex sensitivity, markers of cardiac vagal control, in 13 healthy subjects. BACKGROUND: Evidence for the beneficial effects of aldosterone antagonists comes from studies showing increased survival rates following their addition to standard heart ...
Moran Andrew - - 2004
OBJECTIVE: Cardiovascular autonomic neuropathy is associated with microalbuminuria in young and middle-aged patients with type 2 diabetes. We examined this relationship and the potential mediating role of blood pressure in older patients. RESEARCH DESIGN AND METHODS: At least two of three components of cardiovascular autonomic testing were completed by 132 ...
Virtanen R - - 2004
Although pulse pressure (PP), heart rate variability (HRV) and baroreflex sensitivity (BRS) have been shown to predict cardiovascular events and mortality in various populations, their relationships have not been clarified. We examined these associations in two separate population-based samples of healthy middle-aged subjects. In population 1, data were obtained from ...
González Julián J - - 2004
The short-term cardiovascular control system is reviewed from the analysis of the heart rate, respiration and blood pressure beat-to-beat variability signals. The present state of the art concerning fractal and non-linear techniques as applied to the cardiovascular system and the differences between both approaches are highlighted. We present results obtained ...
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