Alterations of mature arterioles associated with chronically reduced blood flow

1993 ◽  
Vol 264 (1) ◽  
pp. H40-H44 ◽  
Author(s):  
D. H. Wang ◽  
R. L. Prewitt
Keyword(s):  
Blood Flow ◽  
Vascular Wall ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Adaptive Responses ◽  
Total Blood ◽  
Cross Sectional ◽  
Old Rats ◽  
Total Blood Flow ◽  
Autoregulatory Mechanism

Adaptive responses of mature arterioles were examined after a 38% reduction in total blood flow to the cremaster muscle produced by unilateral orchidectomy in 12-wk-old rats. Four weeks later, the muscle was smaller than the contralateral cremaster, which did not increase in size during this period. Measured by closed-circuit television microscopy, the internal diameters of first- through fourth-order arterioles (1A-4A) were smaller, but wall cross-sectional area was reduced only in 3As. The smaller diameter of the 1A in the orchidectomy muscle resulted in unchanged wall shear rate. As determined from the perfusion-fixed, microfilled cremaster muscles, the total length of the arcading arterioles and the number of 3As were not statistically different, but the total number of 4As was significantly reduced on the orchidectomy side. Therefore, chronic load reduction in a mature muscle resulted in reduced blood flow, decreased number of 4As, and smaller arteriolar internal diameters in the absence of net changes in vascular wall cross-sectional area. A local autoregulatory mechanism related to flow-induced shear stress is suggested as the mechanism mediating the changes.

scholarly journals Sequential alterations in the diameters of capillaries in rabbit skeletal muscle following deep transverse friction - a morphometric study

2005 ◽  
Vol 61 (2) ◽  
Author(s):  
M. A. Gregory ◽  
M. N. Deane ◽  
M. Marsh
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Biceps Femoris ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Biceps Femoris Muscle ◽  
Beneficial Effects ◽  
The Cross

Objective: The precise mechanisms by which massage promotes repair in injured soft tissue are unknown. Various authorshave attributed the beneficial effects of massage to vasodilation and increased skin and muscle blood flow. The aim of this study was to determine whether deep transverse friction massage (DTF) causes capillary vasodilation in untraumatised skeletal muscle. Setting: Academic institution.Interventions: Twelve New Zealand white rabbits were anaesthetised and the left biceps femoris muscle received 10 minutes of DTF. Following treatment, wedge biopsies were taken from the musclewithin 10 minutes of treatment (R1 - 4), 24 hours (R5 - 8) and 6 days(R9 - 12) after treatment. To serve as controls, similar biopsies weretaken from the right biceps femoris of animals. The samples were fixed, dehydrated and embedded in epoxy resin.Transverse sections (1µm) of muscle were cut, stained with 1% aqueous alkaline toluidine blue and examined with a light microscope using a 40X objective. Images containing capillaries were captured using an image analyser with SIS software and the cross sectional diameters of at least 60 capillaries were measured from each specimen. Main Outcome Measures: Changes in capillary diameter. Results: The mean capillary diameters in control muscle averaged 4.76 µm. DTF caused a significant immediate increase of 17.3% in cross sectional area (p<0.001), which was not significantly increased by 10.0% after 24 hours (p>0.05). Six days after treatment the cross-sectional area of the treated muscle was 7.6% smaller than the controls. Conclusions: This confirms the contention that DTF stimulates muscle blood flow immediately after treatment and this may account for its beneficial effects in certain conditions. 

scholarly journals Changes in lower extremity blood flow during advancing phases of pregnancy and the effects of special footwear

2017 ◽  
Vol 16 (3) ◽  
pp. 214-219 ◽  
Author(s):  
Marta Gimunová ◽  
Martin Zvonař ◽  
Kateřina Kolářová ◽  
Zdeněk Janík ◽  
Ondřej Mikeska ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Cross Sectional Area ◽  
Popliteal Vein ◽  
Control Group ◽  
Venous Disease ◽  
Venous Blood Flow ◽  
Sectional Area ◽  
Cross Sectional ◽  
Experimental Group

Abstract Background During pregnancy, a number of changes affecting venous blood flow occur in the circulatory system, such as reduced vein wall tension or increased exposure to collagen fibers. These factors may cause blood stagnation, swelling of the legs, or endothelial damage and consequently lead to development of venous disease. Objectives The aim of this study is to evaluate the effect of special footwear designed to improve blood circulation in the feet on venous blood flow changes observed during advancing phases of pregnancy. Methods Thirty healthy pregnant women participated in this study at 25, 30, and 35 weeks of gestation. Participants were allocated at random to an experimental group (n = 15) which was provided with the special footwear, or a control group (n = 15). At each data collection session, Doppler measurements of peak systolic blood flow velocity and cross-sectional area of the right popliteal vein were performed using a MySonoU6 ultrasound machine with a linear transducer (Samsung Medison). The differences were compared using Cohen’s d test to calculate effect size. Results With advancing phases of pregnancy, peak systolic velocity in the popliteal vein decreased significantly in the control group, whereas it increased significantly in the experimental group. No significant change in cross-sectional area was observed in any of the groups. Conclusions Findings in the experimental group demonstrated that wearing the footwear tested may prevent venous blood velocity from reducing during advanced phases of pregnancy. Nevertheless, there is a need for further investigation of the beneficial effect on venous flow of the footwear tested and its application.

Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe

2009 ◽  
Vol 297 (4) ◽  
pp. R1058-R1065 ◽  
Author(s):  
E. Brøndum ◽  
J. M. Hasenkam ◽  
N. H. Secher ◽  
M. F. Bertelsen ◽  
C. Grøndahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Venous Pressure ◽  
Upright Position ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Jugular Veins ◽  
Cross Sectional ◽  
Spontaneously Breathing

How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 ± 11 mmHg (mean ± SE), carotid flow was 0.7 ± 0.2 l/min, and carotid cross-sectional area was 0.85 ± 0.04 cm2. Central venous pressure (CVP) was 4 ± 2 mmHg, jugular flow was 0.7 ± 0.2 l/min, and jugular cross-sectional area was 0.14 ± 0.04 cm2 ( n = 4). Carotid arterial and jugular venous pressures at head level were 118 ± 9 and −7 ± 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 ± 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to −1 ± 2 mmHg ( P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 ± 0.6 cm2 ( P < 0.01), corresponding to accumulation of ∼1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.

Skeletal muscle adaptations following blood flow-restricted training during 30 days of muscular unloading

2010 ◽  
Vol 109 (2) ◽  
pp. 341-349 ◽  
Author(s):  
Summer B. Cook ◽  
Kimberly A. Brown ◽  
Keith DeRuisseau ◽  
Jill A. Kanaley ◽  
Lori L. Ploutz-Snyder
Keyword(s):  
Blood Flow ◽  
Muscle Strength ◽  
Knee Extensor ◽  
Exercise Group ◽  
Cross Sectional Area ◽  
Knee Extensors ◽  
Muscular Endurance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Flow Restriction

This study evaluated the effectiveness of low-load resistance training with a blood flow restriction (LLBFR) to attenuate muscle loss and weakness after 30 days of unilateral lower limb suspension (ULLS). Sixteen subjects (ages 18–50 yr) underwent 30 days of ULLS. Measurements of muscle strength, cross-sectional area, and endurance on the knee extensors and plantar flexors were collected before and after ULLS. Plasma concentrations of IGF-1 and IGFBP-3 were also assessed. During ULLS, eight subjects (5 males, 3 females) participated in LLBFR three times per week (ULLS + Exercise) while eight subjects (4 males, 4 females) did not exercise (ULLS). The blood flow-restricted exercise consisted of dynamic knee extension at 20% of the subject's isometric maximum voluntary contraction coupled with a suprasystolic blood flow restriction. After 30 days of limb suspension, the ULLS + Exercise group experienced minimal and insignificant losses in knee extensor cross-sectional area and strength (1.2% and 2.0%, respectively; P ≤ 0.05), while the ULLS group demonstrated significant reductions in cross-sectional area and strength (7.4% and 21%, respectively). Decrements in plantar flexor strength (23.7%) and cross-sectional area (7.4%) were observed after ULLS ( P < 0.05) and were of similar magnitude between the experimental groups ( P > 0.05). Muscular endurance in the knee extensors improved 31% in the ULLS + Exercise group, while it decreased 24% in the ULLS group ( P = 0.01). No changes were seen in hormone concentrations throughout the study. In conclusion, LLBFR of the knee extensors is effective in maintaining muscle strength and size during 30 days of ULLS and results in improved knee extensor muscular endurance.

scholarly journals 4D flow MRI for intracranial hemodynamics assessment in Alzheimer’s disease

2016 ◽  
Vol 36 (10) ◽  
pp. 1718-1730 ◽  
Author(s):  
Leonardo A Rivera-Rivera ◽  
Patrick Turski ◽  
Kevin M Johnson ◽  
Carson Hoffman ◽  
Sara E Berman ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Flow ◽  
Pulsatility Index ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
4D Flow Mri ◽  
4D Flow ◽  
Cross Sectional ◽  
Flow Mri

Cerebral blood flow, arterial pulsation, and vasomotion play important roles in the transport of waste metabolites out of the brain. Impaired vasomotion results in reduced driving force for the perivascular/glymphatic clearance of beta-amyloid. Noninvasive cerebrovascular characteristic features that potentially assess these transport mechanisms are mean blood flow (MBF) and pulsatility index (PI). In this study, 4D flow MRI was used to measure intra-cranial flow features, particularly MBF, PI, resistive index (RI) and cross-sectional area in patients with Alzheimer’s disease (AD), mild cognitive impairment and in age matched and younger cognitively healthy controls. Three-hundred fourteen subjects participated in this study. Volumetric, time-resolved phase contrast (PC) MRI data were used to quantify hemodynamic parameters from 11 vessel segments. Anatomical variants of the Circle of Willis were also cataloged. The AD population reported a statistically significant decrease in MBF and cross-sectional area, and also an increase in PI and RI compared to age matched cognitively healthy control subjects. The 4D flow MRI technique used in this study provides quantitative measurements of intracranial vessel geometry and the velocity of flow. Cerebrovascular characteristics features of vascular health such as pulsatility index can be extracted from the 4D flow MRI data.

scholarly journals Regional hypoxic cerebral vasodilation facilitated by diameter changes primarily in anterior versus posterior circulation

2016 ◽  
Vol 37 (6) ◽  
pp. 2025-2034 ◽  
Author(s):  
J Mikhail Kellawan ◽  
John W Harrell ◽  
Alejandro Roldan-Alzate ◽  
Oliver Wieben ◽  
William G Schrage
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Vascular Reactivity ◽  
Cerebral Arteries ◽  
Posterior Circulation ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Left And Right ◽  
The Right

The inability to quantify cerebral blood flow and changes in macrocirculation cross-sectional area in all brain regions impedes robust insight into hypoxic cerebral blood flow control. We applied four-dimensional flow magnetic resonance imaging to quantify cerebral blood flow (ml • min−1) and cross-sectional area (mm2) simultaneously in 11 arteries. In healthy adults, blood pressure, O2 Saturation (SpO2), and end-tidal CO2 were measured at baseline and steady-state hypoxia (FiO2 = 0.11). We investigated left and right: internal carotid, vertebral, middle, anterior, posterior cerebral arteries, and basilar artery. Hypoxia (SpO2 = 80±2%) increased total cerebral blood flow from 621±38 to 742±50 ml • min−1 ( p < 0.05). Hypoxia increased cerebral blood flow, except in the right posterior cerebral arteries. Hypoxia increased cross-sectional area in the anterior arteries (left and right internal carotid arteries, left and right middle, p < 0.05; left and right anterior p = 0.08) but only the right vertebral artery of the posterior circulation. Nonetheless, relative cerebral blood flow distribution and vascular reactivity (Δ%cerebral blood flow • ΔSpO2−1) were not different between arteries. Collectively, moderate hypoxia: (1) increased cerebral blood flow, but relative distribution remains similar to normoxia, (2) evokes similar vascular reactivity between 11 arteries, and (3) increased cross-sectional area primarily in the anterior arteries. This study provides the first wide-ranging, quantitative, functional and structural data regarding intracranial arteries during hypoxia in humans, highlighting cerebral blood flow regulation of microcirculation and macrocirculation differs between anterior and posterior circulation.

scholarly journals Does Blood Flow Restriction Training Improve Quadriceps Measures After Arthroscopic Knee Surgery? A Critically Appraised Topic

2020 ◽  
Vol 25 (5) ◽  
pp. 221-226
Author(s):  
Erik H. Arve ◽  
Emily Madrak ◽  
Aric J. Warren
Keyword(s):  
Blood Flow ◽  
Cross Sectional Area ◽  
Knee Surgery ◽  
Blood Flow Restriction ◽  
Sectional Area ◽  
Bottom Line ◽  
Cross Sectional ◽  
Arthroscopic Knee Surgery ◽  
Flow Restriction ◽  
Arthroscopic Knee

Focused Clinical Question: Is there evidence to suggest that blood flow restriction (BFR) training improves strength, cross-sectional area, and thigh girth of the quadriceps musculature in patients after arthroscopic surgical procedures of the knee? Clinical Bottom Line: There is moderate consistent, but low-level, evidence supporting the use of BFR training to improve knee extensor muscular outcomes (strength, cross-sectional area, and/or thigh girth) immediately after arthroscopic knee surgery.

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