Effects of autonomic disruption and inactivity on venous vascular function

2000 ◽  
Vol 278 (2) ◽  
pp. H515-H520 ◽  
Author(s):  
Jill M. Wecht ◽  
Ronald E. de Meersman ◽  
Joseph P. Weir ◽  
William A. Bauman ◽  
David R. Grimm
Keyword(s):  
Vascular Function ◽  
Vascular System ◽  
Analysis Of Covariance ◽  
Active Group ◽  
Vasomotor Tone ◽  
Venous Compliance ◽  
Venous Capacitance ◽  
Mean Values ◽  
Sedentary Group ◽  
Cord Injury

The effects of autonomic disruption and inactivity were studied on the venous vascular system. Forty-eight subjects, 24 with spinal cord injury (SCI) and 12 sedentary and 12 active able-bodied controls, participated in this study. Peripheral autonomic data were obtained to estimate sympathetic vasomotor control [low-frequency component of systolic blood pressure (LFSBP)]. Vascular parameters were determined using strain-gauge venous occlusion plethysmography: venous capacitance (VC), venous emptying rate (VER), and total venous outflow (VOt). An additional vascular parameter was calculated: venous compliance [(VC/occlusion pressure) × 100]. VC and VOt were significantly different (SCI < sedentary < active). VER adjusted for VC was not different for any group comparison, whereas venous compliance was significantly lower in the SCI group than in the able-bodied groups and in the sedentary group compared with the active group. Regression analysis for the total group revealed a significant relationship between LFSBP and venous compliance ( r = 0.64, P < 0.0001). After controlling for LFSBP through analysis of covariance, we found that mean differences for all venous vascular parameters did not change from unadjusted mean values. Our findings suggest that in subjects with SCI, the loss of sympathetic vasomotor tone contributes more than inactivity to reductions in venous vascular function. Heightened VC, VOt, vasomotor tone, and venous compliance in the active group compared with the sedentary group imply that regular endurance training contributes to optimal venous vascular function and peripheral autonomic integrity.

Cardiac homeostasis is independent of calf venous compliance in subjects with paraplegia

2003 ◽  
Vol 284 (6) ◽  
pp. H2393-H2399 ◽  
Author(s):  
Jill M. Wecht ◽  
Ronald E. De Meersman ◽  
Joseph P. Weir ◽  
Ann M. Spungen ◽  
William A. Bauman
Keyword(s):  
Cardiac Output ◽  
Vascular Function ◽  
Structural Changes ◽  
Random Order ◽  
Venous Occlusion ◽  
Control Group ◽  
Calf Circumference ◽  
Venous Compliance ◽  
Venous Capacitance ◽  
Cardiac Hemodynamics

The purpose of this study was to examine cardiac hemodynamics during acute head-up tilt (HUT) and calf venous function during acute head-down tilt (HDT) in subjects with paraplegia compared with sedentary nondisabled controls. Nineteen paraplegic males (below T6) and nine age-, height-, and weight-matched control subjects participated. Heart rate, stroke volume, and cardiac output were assessed using the noninvasive acetylene uptake method. Venous vascular function of the calf was assessed using venous occlusion plethysmography. After supine measurements were collected, the table was moved to 10° HDT followed by the three levels of HUT (10, 35, and 75°) in random order. Cardiac hemodynamics were similar between the groups at all positions. Calf circumference was significantly reduced in the paraplegic group compared with the control group ( P < 0.001). Venous capacitance and compliance were significantly reduced in the paraplegic compared with control group at supine and HDT. Neither venous capacitance ( P = 0.37) nor compliance ( P = 0.19) increased from supine with 10° HDT in the paraplegic group. A significant linear relationship was established between supine venous compliance and supine cardiac output in the control group ( r = 0.80, P < 0.02) but not in the paraplegic group. The findings of reduced calf circumference and similar venous capacitance at supine rest and 10° HDT in the paraplegic group imply that structural changes may have limited venous dispensability in individuals with chronic paraplegia. Furthermore, the lack of a relationship between supine venous compliance and supine cardiac output suggests that cardiac homeostasis does not rely on venous compliance in subjects with paraplegia.

scholarly journals CORP: Ultrasound assessment of vascular function with the passive leg movement technique

2017 ◽  
Vol 123 (6) ◽  
pp. 1708-1720 ◽  
Author(s):  
Jayson R. Gifford ◽  
Russell S. Richardson
Keyword(s):  
Vascular Function ◽  
Cardiovascular Health ◽  
Vascular System ◽  
The Elderly ◽  
Passive Movement ◽  
Flow Mediated Dilation ◽  
Peripheral Vascular ◽  
Ultrasound Assessment ◽  
Leg Movement ◽  
Hyperemic Response

As dysfunction of the vascular system is an early, modifiable step in the progression of many cardiovascular diseases, there is demand for methods to monitor the health of the vascular system noninvasively in clinical and research settings. Validated by very good agreement with more technical assessments of vascular function, like intra-arterial drug infusions and flow-mediated dilation, the passive leg movement (PLM) technique has emerged as a powerful, yet relatively simple, test of peripheral vascular function. In the PLM technique, the change in leg blood flow elicited by the passive movement of the leg through a 90° range of motion is quantified with Doppler ultrasound. This relatively easy-to-learn test has proven to be ≤80% dependent on nitric oxide bioavailability and is especially adept at determining peripheral vascular function across the spectrum of cardiovascular health. Indeed, multiple reports have documented that individuals with decreased cardiovascular health such as the elderly and those with heart failure tend to exhibit a substantially blunted PLM-induced hyperemic response (~50 and ~85% reduction, respectively) compared with populations with good cardiovascular health such as young individuals. As specific guidelines have not yet been put forth, the purpose of this Cores of Reproducibility in Physiology (CORP) article is to provide a comprehensive reference for the assessment and interpretation of vascular function with PLM with the aim to increase reproducibility and consistency among studies and facilitate the use of PLM as a research tool with clinical relevance.

Effects of natriuretic peptides and nitroprusside on venous function in trout

1997 ◽  
Vol 273 (2) ◽  
pp. R527-R539 ◽  
Author(s):  
K. R. Olson ◽  
D. J. Conklin ◽  
A. P. Farrell ◽  
J. E. Keen ◽  
Y. Takei ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Natriuretic Peptides ◽  
Aortic Pressure ◽  
Systemic Resistance ◽  
Venous Compliance ◽  
Venous Capacitance ◽  
Unstressed Volume ◽  
Ventral Aorta

Active venous regulation of cardiovascular function is well known in mammals but has not been demonstrated in fish. In the present studies, the natriuretic peptides (NP) rat atrial natriuretic peptide (ANP) and trout ventricular natriuretic peptide (VNP), clearance receptor inhibitor SC-46542, and sodium nitroprusside (SNP) were infused into unanesthetized trout fitted with pressure cannulas in the ventral aorta, dorsal aorta, and ductus Cuvier, and a ventral aorta (VA) flow probe was used to measure cardiac output (CO). In another group, in vivo vascular (venous) capacitance curves were obtained during ANP or SNP infusion. The in vitro effects of NP on vessels and the heart were also examined. ANP, VNP, and SC-46542 decreased central venous pressure (PVen), CO, stroke volume (SV), and gill resistance (RG), whereas systemic resistance (RS) and heart rate (HR) increased. Dorsal aortic pressure (PDA) transiently increased and then fell even though RS remained elevated. ANP decreased mean circulatory filling pressure (MCFP), increased vascular compliance at all blood volumes, and increased unstressed volume in hypovolemic fish. ANP had no direct effect on the heart. ANP responses in vivo were not altered in trout made hypotensive by prior treatment with the angiotensin-converting enzyme inhibitor lisinopril. SNP reduced ventral aortic pressure (PVA), PDA, and RS, increased CO and HR, but did not affect PVen, SV, or RG. SNP slightly decreased MCFP but did not affect compliance or unstressed volume. In vitro, large systemic arteries were more responsive than veins to NP, whereas SNP relaxed both. These results show that, in vivo, NP decrease venous compliance, thereby decreasing venous return, CO, and arterial pressure. Conversely, SNP hypotension is due to decreased RS. This is the first evidence for active regulation of venous capacitance in fish, which probably occurs in small veins or venules. The presence of venous baroreceptors is also suggested.

scholarly journals The Role of Uridine Adenosine Tetraphosphate in the Vascular System

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Takayuki Matsumoto ◽  
Rita C. Tostes ◽  
R. Clinton Webb
Keyword(s):  
Smooth Muscle ◽  
Cardiovascular Diseases ◽  
Endothelial Dysfunction ◽  
Arterial Hypertension ◽  
Smooth Muscle Cells ◽  
Vascular Function ◽  
Purinergic Receptors ◽  
Potential Role ◽  
Vascular System

The endothelium plays a pivotal role in vascular homeostasis, and endothelial dysfunction is a major feature of cardiovascular diseases, such as arterial hypertension, atherosclerosis, and diabetes. Recently, uridine adenosine tetraphosphate (Up4A) has been identified as a novel and potent endothelium-derived contracting factor (EDCF). Up4A structurally contains both purine and pyrimidine moieties, which activate purinergic receptors. There is an accumulating body of evidence to show that Up4A modulates vascular function by actions on endothelial and smooth muscle cells. In this paper, we discuss the effects of Up4A on vascular function and a potential role for Up4A in cardiovascular diseases.

Altitude acclimatization attenuates plasma ammonia accumulation during submaximal exercise

1987 ◽  
Vol 63 (2) ◽  
pp. 758-764 ◽  
Author(s):  
P. M. Young ◽  
P. B. Rock ◽  
C. S. Fulco ◽  
L. A. Trad ◽  
V. A. Forte ◽  
...  
Keyword(s):  
Sea Level ◽  
Endurance Performance ◽  
Ammonia Concentration ◽  
Submaximal Exercise ◽  
Active Group ◽  
Cycle Exercise ◽  
Plasma Ammonia ◽  
Altitude Acclimatization ◽  
Ammonia Accumulation ◽  
Sedentary Group

This study examined the effects of acclimatization to 4,300 m altitude on changes in plasma ammonia concentrations with 30 min of submaximal [75% maximal O2 uptake (VO2max)] cycle exercise. Human test subjects were divided into a sedentary (n = 6) and active group (n = 5). Maximal uptake (VO2max) was determined at sea level and at high altitude (HA; 4,300 m) after acute (t less than 24 h) and chronic (t = 13 days) exposure. The VO2max of both groups decreased 32% with acute HA when compared with sea level. In the sedentary group, VO2max decreased an additional 16% after 13 days of continuous residence at 4,300 m, whereas VO2max in the active group showed no further change. In both sedentary and active subjects, plasma ammonia concentrations were increased (P less than 0.05) over resting levels immediately after submaximal exercise at sea level as well as during acute HA exposure. With chronic HA exposure, the active group showed no increase in plasma ammonia immediately after submaximal exercise, whereas the postexercise ammonia in the sedentary group was elevated but to a lesser extent than at sea level or with acute HA exposure. Thus postexercise plasma ammonia concentration was decreased with altitude acclimatization when compared with ammonia concentrations following exercise performed at the same relative intensity at sea level or acute HA. This decrease in ammonia accumulation may contribute to enhanced endurance performance and altered substrate utilization with exercise following acclimatization to altitude.

scholarly journals Limb venous tone and responsiveness in hypertensive humans

2008 ◽  
Vol 105 (3) ◽  
pp. 894-901 ◽  
Author(s):  
Erin P. Delaney ◽  
Colin N. Young ◽  
Angela DiSabatino ◽  
Michael E. Stillabower ◽  
William B. Farquhar
Keyword(s):  
Repeated Measures ◽  
Muscle Tone ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Quadratic Regression ◽  
Venous Compliance ◽  
Venous Tone ◽  
Venous Capacitance ◽  
Regression Parameters ◽  
One Way Anova

Hypertensive (HTN) animal models demonstrate lower venous compliance as well as increased venous tone and responsiveness compared with normotensive (NTN) controls. However, the extent to which findings in experimental animals can be extended to humans is unknown. Forearm and calf venous compliance were quantified in 9 NTN (23 ± 1 yr) and 9 HTN (24 ± 1 yr) men at baseline, after administration of nitroglycerin (NTG), during a cold pressor test (CP), and post-handgrip exercise ischemia (PEI). Individual pressure-volume relationships from a cuff deflation protocol (1 mmHg/s) were modeled with a quadratic regression. Regression parameters β1 and β2 were used to calculate compliance. A one-way ANOVA was used to compare the beta parameters and a repeated-measures ANOVA was used to compare volumes across all pressures (between groups at baseline and within groups during perturbations). Limb venous compliance was similar between groups (forearm: NTN β1 = 0.11 ± 0.01 and β2 = −0.00097 ± 0.0001, HTN β1 = 0.10 ± 0.01 and β2 = −0.00088 ± 0.0001; calf: NTN β1 = 0.12 ± 0.01 and β2 = −0.00102 ± 0.0001, HTN β1 = 0.11 ± 0.01 and β2 = −0.00090 ± 0.0001). However, at baseline, volume across all pressures (i.e., capacitance) was lower in the forearm ( P ≤ 0.01) and tended to be lower in the calf ( P = 0.08) in HTN subjects. Venous compliance was not altered by any perturbation in either group. Forearm volume was increased during NTG in HTN subjects only. While venous compliance was similar between NTN and HTN adults, HTN adults have lower forearm venous capacitance (volume) which is increased with NTG. These data suggest that young HTN adults may have augmented venous smooth muscle tone compared with NTN controls.

Vascular function in alcohol-treated pregnant and nonpregnant mice

2001 ◽  
Vol 281 (5) ◽  
pp. R1449-R1455 ◽  
Author(s):  
Jocelynn L. Cook ◽  
Yunlong Zhang ◽  
Sandra T. Davidge
Keyword(s):  
Nitric Oxide ◽  
Vascular Function ◽  
Vascular System ◽  
Prenatal Alcohol Exposure ◽  
Control Diet ◽  
Alcohol Exposure ◽  
Ethanol Exposure ◽  
Vascular Response ◽  
Oxide Component ◽  
Pregnant Mice

The effect of alcohol on maternal vascular adaptations to pregnancy is unknown. This study was designed to determine the effect of alcohol consumption on nitric oxide-mediated vascular function in mice during pregnancy. Female pregnant or nonpregnant C57BL/6J mice were fed a control diet or a liquid diet of 25% ethanol-derived calories for 13 days (from gestational days 6–18). Phenylephrine vasoconstriction was blunted in pregnancy compared with the nonpregnant state due to enhanced nitric oxide modulation, which was impaired by ethanol exposure. Although the EC50 and maximal responses to methacholine were not different in nonpregnant vs. pregnant mice, the nitric oxide component to methacholine-induced vasorelaxation was greater in the pregnant mice. Interestingly, alcohol affected only the pregnant animals in their response to methacholine. These data indicate that alcohol reduced the nitric oxide modulation of vascular response, which was more pronounced during pregnancy. These studies provide novel information regarding the effects of alcohol on the maternal vascular system during pregnancy and thereby contribute to further understanding of the adverse effects associated with prenatal alcohol exposure.

Effect of juvenile wood on strength properties and dimensional stability of black spruce medium-density fiberboard panels

Holzforschung ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jun Li Shi ◽  
Shu Yin Zhang ◽  
Bernard Riedl
Keyword(s):  
Water Absorption ◽  
Dimensional Stability ◽  
Juvenile Wood ◽  
Black Spruce ◽  
Medium Density Fiberboard ◽  
Strength Properties ◽  
Analysis Of Covariance ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Mean Values

Abstract Strength properties and dimensional stability of medium-density fiberboard (MDF) panels made from black spruce (Picea mariana [Mill.] BSP.) 0–20, 21–40, and over 40 year old fiber were studied. An analysis of covariance (ANCOVA) was performed to examine the differences in modulus of rupture (MOR), modulus of elasticity (MOE), and thickness swell (TS) of the three types of panels, while panel density was treated as a covariate in order to adjust the mean values that were partly attributed to panel density. The results indicate that MOR, internal bond (IB), and water absorption of MDF panels made from 0–20 year old fiber, which contained 100% juvenile wood, were significantly superior to those of panels made from 21–40 and over 40 year old fiber; but linear expansion (LE) of MDF panels made from 0–20 year old fiber was significantly larger than that of panels from the other two age classes. The differences in MOR, IB, water absorption, and LE between panels made from 21–40 and over 40 year old fiber were not significant. The comparisons of panel MOE and TS were relatively dependent on panel density due to existence of interactions among the three age groups.

scholarly journals Blood supply and vascular reactivity of the spinal cord under normal and pathological conditions

2011 ◽  
Vol 15 (3) ◽  
pp. 238-251 ◽  
Author(s):  
Nikolay L. Martirosyan ◽  
Jeanne S. Feuerstein ◽  
Nicholas Theodore ◽  
Daniel D. Cavalcanti ◽  
Robert F. Spetzler ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Blood Supply ◽  
Vascular Reactivity ◽  
Vascular System ◽  
Spinal Cord Blood Flow ◽  
Arterial Blood ◽  
Severity Of Injury ◽  
Cord Injury

The authors present a review of spinal cord blood supply, discussing the anatomy of the vascular system and physiological aspects of blood flow regulation in normal and injured spinal cords. Unique anatomical functional properties of vessels and blood supply determine the susceptibility of the spinal cord to damage, especially ischemia. Spinal cord injury (SCI), for example, complicating thoracoabdominal aortic aneurysm repair is associated with ischemic trauma. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic SCI causes complex changes in spinal cord blood flow, which are closely related to the severity of injury. Manipulating physiological parameters such as mean arterial blood pressure and intrathecal pressure may be beneficial for patients with an SCI. Studying the physiopathological processes of the spinal cord under vascular compromise remains challenging because of its central role in almost all of the body's hemodynamic and neurofunctional processes.

scholarly journals Prayer-related Physical Activities for Cardiovascular Health

2020 ◽  
Author(s):  
Mahmoud A. Alomari ◽  
Dana M. Shqair ◽  
Khaldoon Alawneh ◽  
Omar F. Khabour ◽  
Mahmoud E. Nazzal ◽  
...  
Keyword(s):  
Physical Activity ◽  
Blood Flow ◽  
Vascular Function ◽  
Cardiovascular Health ◽  
Circulatory System ◽  
Arterial Occlusion ◽  
Physical Activities ◽  
Vascular Effects ◽  
Venous Capacitance ◽  
Healthy Participants

Introduction: Muslims are obligated to pray 5 times daily. Each prayer is a number of rakaa completed with a set of physical movements, preferably in the neighborhood masjid. The vascular effects of religious-related physical activities (RRPA) are not known, despite the well-known cardiovascular benefits of regular physical activity. Therefore, the current study examines the relationships of RRPA with vascular measures. Methodology: Arterial and venous indices at rest and after 5 of arterial occlusion were examined in 192 healthy participants (age: 19-85 years) using strain gauge plethysmography. The participants’ RRPA were collected in a 1-to-1 interview, including prayer (PN) and rakaa number (RN) performed, distance (DW) and time (TW) required to walk to the masjid, and the daily (DA) and weekly (WA) attendance to the masjid. Results: Resting blood flow correlated significantly with DW, TW, DA, and WA (r=0.2-0.4; p<0.01). Resting vascular resistance correlated with DW, TW, DA, and WA (r=-0.14-0.2; p<0.05). Resting venous capacitance correlated with DW, TW, DA, and WA (r=0.14-0.17; p<0.05). Resting outflow correlated with DW, TW, DA, and WA (r=0.15-0.2; p<0.05). Occlusion blood flow correlated with DW (r=0.17; p=0.02). Occlusion outflow correlated with DW and DA (r=0.16-0.17; p<0.05). Additionally, arterial and venous indices were greater (p<0.05) in the participants regularly prayed in the masjid. Discussion: The results confirm the importance of physical activities for the circulatory system. Uniquely, the data shows that RRPA might contribute to the maintenance of vascular function.

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