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Zhou Xiaoyan X Department of Cardiovascular Diseases, Merck Research Laboratories, Rahway, New Jersey, USA. - - 2011
We investigated the effects of chronic mineralocorticoid receptor blockade with eplerenone on the development and progression of hypertension and end organ damage in Dahl salt-sensitive rats. Eplerenone significantly attenuated the progressive rise in systolic blood pressure (SBP) (204 ± 3 vs. 179±3 mmHg, p < 0.05), reduced proteinuria (605.5 ± ...
Kakade R H - - 2011
A double drum dryer working under atmospheric pressure was developed for water evaporation rate of 20 kg/h. Potato slurry of 12% solid concentration was dried to obtain potato flakes. Experiments were carried out at drum speed of 5 to 30 rpm, steam pressure 2 to7 kg/cm(2) gauge (saturation temperature 120-164 °C) and liquid level ...
Navasiolava Nastassia M - - 2011
Actual and simulated microgravity induces hypovolemia and cardiovascular deconditioning, associated with vascular dysfunction. We hypothesized that vasoconstriction of skin microcirculatory bed should be altered following 7days of simulated microgravity in order to maintain cardiovascular homeostasis during active standing. Eight healthy men were studied before and after 7days of simulated microgravity ...
Jan Yih-Kuen - - 2010
To investigate the efficacy of wheelchair tilt-in-space and recline on enhancing skin perfusion over the ischial tuberosity in wheelchair users with spinal cord injury (SCI). Repeated-measures, intervention, and outcomes-measure design. A university research laboratory. Wheelchair users with SCI (N=11; 9 men, 2 women; mean ± SD age, 37.7±14.2y; body mass ...
Porta Alberto - - 2011
In physiological conditions, heart period (HP) affects systolic arterial pressure (SAP) through diastolic runoff and Starling's law, but, the reverse relation also holds as a result of the continuous action of baroreflex control. The prevailing mechanism sets the dominant temporal direction in the HP-SAP interactions (i.e., causality). We exploited cross-conditional ...
Schroeder Christoph - - 2011
We tested the hypothesis that detailed anthropometric and hemodynamic measurements predict orthostatic tolerance in neurally mediated syncope patients. In addition, we tested whether orthostatic tolerance is related to syncope frequency in real life. Earlier studies in patients with neurally mediated syncope suggested that orthostatic heart rate and blood pressure responses ...
Roessler Andreas - - 2011
We investigated whether head up tilt (HUT) with and without simultaneous epinephrine infusion modulate plasma adrenomedullin. We studied eight healthy male volunteers, using two 5 min 70° HUT trials: control (saline infusion) and intervention (epinephrine infusion, titrated to a dose which increased supine systolic pressure by 20% above resting values). Protocols ...
Bressel Eadric - - 2010
Bicycle seat pressure is thought to be the principal risk factor for bicycle seat injuries such as erectile dysfunction; however there is a lack of understanding regarding the characteristics of a cyclist that predict bicycle seat pressure. The purpose of this study was to determine if select attributes of a ...
Montesano Marilisa - - 2010
The aim of our study was to investigate cardiovascular autonomic activity during wakefulness, using cardiovascular tests, in a population of children with OSAS. Prospective study. Sleep unit of an academic center. We included 25 children (mean age 10.2 +/- 2.3 years) undergoing a diagnostic assessment for OSAS, and 25 age-matched ...
Stenger Michael B - - 2010
INTRODUCTION: Post-spaceflight orthostatic intolerance affects approximately 30% of short-duration and 80% of long-duration crewmembers. While the current NASA antigravity suit is effective during Space Shuttle re-entry, it is not designed to be worn postflight and has several drawbacks. The purpose of this study was to evaluate the use of commercially ...
Crandall C G - - 2010
As much as 50% of cardiac output can be distributed to the skin in the hyperthermic human, and therefore the control of cutaneous vascular conductance (CVC) becomes critical for the maintenance of blood pressure. Little is known regarding the magnitude of cutaneous vasoconstriction in profoundly hypotensive individuals while heat stressed. ...
Hachiya T - - 2010
Central blood volume loss to venous pooling in the lower extremities and vasoconstrictor response are commonly viewed as key factors to distinguish between individuals with high and low tolerance to orthostatic stress. In this study, we analyzed calf vasoconstriction as a function of venous pooling during simulated orthostatic stress. We ...
Czarkowska Hanna - - 2010
BACKGROUND AND PURPOSE: It is not clear how cardiovascular autonomic nervous system dysfunction can affect falls in Parkinson disease (PD) patients. The aim of the study was to evaluate cardiovascular autonomic responses to orthostatic stress and occurrence of falls in PD patients over a period of 1-2 years. MATERIAL AND ...
Tzeng Yu-Chieh - - 2010
The cerebrovasculature dilates or constricts in response to acute blood pressure changes to stabilize cerebral blood flow across a range of blood pressures. It is unclear, however, whether such dynamic cerebral autoregulation (dCA) is equally effective in responding to falling versus rising blood pressure. In this study we applied a ...
Bundgaard-Nielsen Morten - - 2010
Both hypovolemia and a fluid overload are detrimental for outcome in surgical patients but the effort to establish normovolemia is hampered by the lack of an operational clinical definition. Manipulating the central blood volume on a tilt table demonstrates that the flat part of the Frank-Starling curve is reached when ...
Folino Antonio Franco - - 2010
The aim of our study was to identify specific age-related hemodynamic changes during upright tilt test in patients with vasovagal syncope. We studied 115 subjects who were referred to us for unexplained syncope during 65 degrees tilt with pharmacological challenge (s.l. nitrate) by noninvasive monitoring of blood pressure (Finometer). Two ...
Ryan Kathy L - - 2010
Heart period variability (HPV) metrics have been suggested for use in medical monitoring of trauma patients. This study sought to ascertain the use of various HPV metrics in tracking central blood volume during simulated hemorrhage in individual humans. One hundred one healthy nonsmoking volunteers (58 men, 43 women) were instrumented ...
Iacoviello Massimo - - 2010
AIMS: The involvement of arterial baroreflex function in the pathophysiology of vasovagal syncope (VVS) is controversial, and there are no published data supporting its clinical usefulness. The aim of this study was to evaluate the role of arterial baroreflex sensitivity (BRS) at baseline and during head-up tilt testing (HUT) in ...
Czajkowska Jadwiga - - 2010
BACKGROUND: The move from lying to standing is typically associated with a variety of physiological and neurohumoral changes, most especially a slight increase in systolic blood pressure (SBP). Decreased efficacy of the various mechanisms that control orthostatic blood pressure (BP) regulation may result in lightheadedness, dizziness, syncope, and cerebral hypoperfusion. ...
Fagard Robert H - - 2010
Aims of the study were to assess in an elderly population the prevalences of orthostatic hypotension at different times after standing and of nighttime reverse dipping on ambulatory blood pressure monitoring, as well as their interrelationships and relative prognostic power for incident cardiovascular events. The study population consisted of 374 ...
Koehle Michael S - - 2010
PURPOSE: Lower body negative pressure (LBNP) augments the acute hypoxic ventilatory response (AHVR) in humans, presumably through altered central integration of baro- and chemoreceptor afferents. This study investigated the effects of LBNP and lower body positive pressure (LBPP) on hypoxic ventilatory decline (HVD) in humans. METHODS: Nine individuals (4 females ...
Dimitrow Pawel Petkow - - 2010
The aim of the study was to assess the effect of hemodialysis (HD) on left ventricular outflow tract gradient (LVOTG) measured both in supine and upright position (provocative maneuver to unload LV cavity by rapid preload reduction). Supine/standing echocardiography was performed immediately before and immediately after HD. For additional verification ...
Clarke Debbie A - - 2010
Initial orthostatic hypotension is common in children. Isometric handgrip increases arterial pressure, central blood volume, cardiac output, and total peripheral resistance. We show that in 14 subjects with initial orthostatic hypotension, isometric handgrip coupled with standing abolished symptoms of initial orthostatic hypotension and minimized decreases in blood pressure and cardiac ...
Kamiya Atsunori - - 2010
Since humans are under ceaseless orthostatic stress, the mechanisms to maintain arterial pressure (AP) against gravitational fluid shift are important. As one mechanism, it was reported that upright tilt reset baroreflex control of renal sympathetic nerve activity (SNA) to a higher SNA in anesthetized rabbits. In the present study, we ...
Goldstein David S DS Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1620, USA. - - 2011
L-threo-3,4-dihydroxyphenylserine (L-DOPS), a norepinephrine (NE) prodrug, is investigational for orthostatic hypotension, which occurs commonly in Parkinson's disease. Adjunctive anti-parkinsonian drugs might interact with L-DOPS. We tested whether L-aromatic amino-acid decarboxylase inhibition by carbidopa (CAR) attenuates L-DOPS conversion to NE and blocks the pressor effect of L-DOPS, whereas catechol-O-methyltransferase inhibition by ...
Koseoglu Zikret - - 2010
Cardiotoxicity is an important adverse effect of tricyclic antidepressants. But cardiac side effects after intoxication with the tetracyclic mianserin are rare. In this paper, we describe a case in which bradycardia and hypotension occured due to mianserin overdose. A 37-year-old woman was admitted to the medical intensive care unit for ...
Skinner Joline E - - 2010
This descriptive population study of 307 public high school students, ages 15 to 17 years, was performed to establish reference ranges for orthostatic changes in heart rate and blood pressure in adolescents, and to identify influential variables. Noninvasive measurements of blood pressure and heart rate were obtained. Reference ranges for ...
Peltier Amanda C AC Department of Neurology, Vanderbilt University School of Medicine, A-0118 Medical Center North, Nashville, Tennessee 37232, USA. - - 2010
We report the case of a 55-year-old man with non-small-cell lung cancer who underwent radiation, chemotherapy with carbotaxol and paclitaxel, and left upper lobe removal 2 years prior to evaluation. He was referred for disabling orthostatic hypotension (113/69 mm Hg supine and 66/47 mm Hg standing after 10 minutes) without ...
Livingstone Kristina - - 2010
Although head-up tilt and upright standing are common methods used to induce orthostatic stress, lower body negative pressure (LBNP) is another safe and easy technique that induces orthostatic stress independently of gravity. However, the use of LBNP in children has never been investigated. The purpose of this pilot study was ...
Coats Brandon W - - 2010
One proposed method to overcome postflight orthostatic intolerance is for astronauts to undergo inflight centrifugation. Cardiovascular responses were compared between centrifuge and gravitational conditions using a seven-compartment cardiovascular model. Vascular resistance, heart rate, and stroke volume values were adopted from literature, while compartmental volumes and compliances were derived from impedance ...
Minns Alicia B - - 2010
INTRODUCTION: Guanfacine is an alpha(2)-adrenoreceptor agonist used for the treatment of attention-deficit hyperactivity disorder and tic disorders. Few reports exist regarding overdose with guanfacine. CASE REPORT: A 16-year-old female with Tourette's syndrome presented with diaphoresis, dry mouth, and hypertension 8 h after ingesting 25 mg of guanfacine. These symptoms improved ...
Jarvis Sara S - - 2010
The volume indifferent point (VIP) is the point within the circulation where blood volume does not change with changes in posture. Because both volume and pressure are unaffected by posture at this point, its location should dictate the filling gradient to the heart. Previously we identified a contribution of the ...
MacDiarmid Scott A - - 2010
To evaluate the orthostatic effects and safety of coadministration of silodosin with the phosphodiesterase-5 inhibitors sildenafil and tadalafil. In this placebo-controlled, open-label crossover study, 22 healthy men aged 45-78 years received 8 mg silodosin for 21 days. On days 7, 14, and 21, subjects also received a single dose of ...
Dyson Kenneth S - - 2010
We compared Modelflow (MF) estimates of cardiac stroke volume (SV) from the finger pressure-pulse waveform (Finometer) with pulsed Doppler ultrasound (DU) of the ascending aorta during acute changes in total peripheral resistance (TPR) in the supine and head-up-tilt (HUT) postures. Twenty-four women were tested during intravenous infusion of 0.005 or ...
Sheriff Don D - - 2010
Tolerance to +G(z) gravitational stress is reduced when +G(z) stress is preceded by exposure to hypogravity (fractional, 0, or negative G(z)). For example, there is an exaggerated fall in eye-level arterial pressure (ELAP) early on during +G(z) stress (head-up tilt; HUT) when this stress is immediately preceded by -G(z) stress ...
Hernandez Juliane P - - 2010
This investigation attempted to determine whether heart-rate and blood pressure responses to maximal acute lower body negative pressure (LBNP) are exacerbated compared with maximal graded LBNP in active older (n = 9, 70 +/- 7 yr) and endurance-trained younger (n = 10, 23 +/- 3 yr) individuals. Heart rate increased ...
Corino V D A - - 2010
During atrial fibrillation (AF), ventricular response is highly irregular and thus the beat-to-beat variation of blood pressure is increased because of variations in filling time and in contractility. Aim of the present study is to investigate the short-term dynamics of RR and SAP series in patients with AF, during rest ...
Thomas Kate N - - 2010
There are several reports on syncope occurring following standing at high altitude (HA), yet description of the detailed physiological responses to standing at HA are lacking. We examined the hypothesis that appropriate physiological adjustments to upright posture would be compromised at HA (5050 m). Ten healthy volunteers stood up rapidly ...
Okpechi Ikechi G - - 2010
Hypertension is the most prevalent cardiovascular disease of adults and is a major risk factor for cardiovascular (CV) and cerebrovascular morbidity and mortality worldwide. Treatment of hypertension leads to reduction of CV morbidity and mortality through blood pressure reduction. The role of renin-angiotensin-aldosterone system (RAAS) in the pathophysiology of hypertension ...
Morimoto Satoshi - - 2010
Rigid control of blood pressure (BP) is essential to prevent cardiovascular disease. However, only about 40% of hypertensive patients undergoing pharmacological intervention with a single agent achieve their BP goals in contemporary clinical practice. Combined therapy using currently available agents is effective in maximizing treatment outcome, although it raises medical ...
Ladino Marco - - 2010
Chronic kidney disease (CKD) affects approximately 26 million adults in the United States and millions of others are at increased risk. Type 2 diabetes and hypertension are the two main causes of CKD. Blood pressure control is critical to slow the progression of CKD. Despite adequate control, however, patients continue ...
Formes Kevin - - 2010
This study sought to test the hypothesis that orthostasis-induced cerebral hypoperfusion would be less severe in physically active elderly humans (ACT group) than in sedentary elderly humans (SED group). The peak O(2) uptake of 10 SED (67.1 +/- 1.4 yr) and 9 ACT (68.0 +/- 1.1 yr) volunteers was determined ...
Goldstein David S - - 2010
OBJECTIVE: Chronic autonomic failure (CAF), as in Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF), typically entails baroreflex failure, neurogenic orthostatic hypotension (NOH), and supine hypertension. The combination might predispose to cardiac ectopy, which in turn might predispose to syncope and falls during manipulations decreasing venous ...
Newton Julia L - - 2009
BACKGROUND: Fatigue is a significant symptom in nonalcoholic fatty liver disease (NAFLD) that impacts upon quality of life and is unrelated to liver disease severity. We examined the relationship between parameters of blood pressure regulation with perception of fatigue in NAFLD. METHODS: Thirty-four non-diabetic subjects with histologically proven, non-cirrhotic NAFLD ...
Schroeder Christoph - - 2009
BACKGROUND: In animals, the endocannabinoid system is activated during hemodynamic insults and restrains blood pressure in part through sympathetic inhibition. MATERIALS AND METHODS: We tested the hypothesis that hemodynamic stress elicited by head-up tilt testing increases systemic endocannabinoid concentrations in humans and that excessive endocannabinoid availability predisposes to presyncope. RESULTS: ...
Lalande Sophie - - 2009
INTRODUCTION: Fighter aircraft pilots are exposed to repetitive headward acceleration (+Gz) during air combat maneuvering. The objective of this study was to compare physiologic responses and the calculated +Gz tolerances of multiple successive +Gz exposures with the responses of the first +Gz exposure. METHODS: There were 13 subjects who performed ...
T??llez Maria J - - 2009
OBJECTIVE: To determine whether the heart rate changes during tilt table testing could be used in the differential diagnosis between vasovagal syncope and chronic autonomic failure. METHODS: We compared the relationship between electrocardiographic R-R intervals and beat-to-beat blood pressure in 43 patients with typical vasovagal responses and 30 patients with ...
Batzel Jerry Joseph - - 2009
To investigate patterns of cardiovascular control, a protocol of head up tilt (HUT) followed by lower body negative pressure (LBNP), which represents a significant cardiovascular control challenge, was employed. Linear regression of beat-to-beat heart rate (HR) and mean blood pressure (MBP) data collected over repeated tests was used to analyze ...
Lucas Rebekah A I - - 2010
Skin surface cooling has been shown to improve orthostatic tolerance; however, the influence of severe heat stress on cardiovascular and cerebrovascular responses to skin cooling remains unknown. Nine healthy males, resting supine in a water-perfusion suit, were heated to +1.0 and +2.0 degrees C elevation in body core temperature (T ...
Hausenloy Derek John - - 2009
AIMS: During head-up tilt (HUT) testing, a period of haemodynamic instability, marked by oscillations in blood pressure, often precedes vasovagal syncope. We hypothesized that the presence of oscillations in blood pressure during HUT testing predicts a positive diagnosis for vasovagal syncope. METHODS AND RESULTS: The haemodynamic profiles of 42 consecutive ...
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