scholarly journals A Theoretical Study on Molar Flux in the Capillary

1970 ◽  
Vol 32 (2) ◽  
Author(s):  
Abdul Malek ◽  
Ashabul Hoque
Keyword(s):  
Blood Pressure ◽  
Osmotic Pressure ◽  
Theoretical Study ◽  
Capillary Blood ◽  
Radial Diffusion ◽  
Tissue Fluid ◽  
Middle Section ◽  
Molar Flux ◽  
Capillary Bed ◽  
Academy Of Sciences

The paper is concerned with the molar flux of oxygen in the capillary blood when oxygen diffuses from blood to tissue fluid at the middle section of the capillary bed where blood pressure and osmotic pressure of blood are equal. The result shows that the molar flux decreases exponentially with the radius of the capillary. Moreover, it is found that the molar flux increases linearly with the increasing of radial diffusion of oxygen. doi: 10.3329/jbas.v32i2.2429 Journal of Bangladesh Academy of Sciences Vol.32(2) 2008 226-233

Gas embolism due to intravenous FC 80 liquid fluorocarbon

1976 ◽  
Vol 40 (5) ◽  
pp. 745-751 ◽  
Author(s):  
D. J. Sass ◽  
R. A. Van Dyke ◽  
E. H. Wood ◽  
S. A. Johnson ◽  
P. Didisheim
Keyword(s):  
Blood Pressure ◽  
Atmospheric Pressure ◽  
Capillary Blood ◽  
Right Atrial ◽  
Gas Embolism ◽  
Pulmonary Capillary ◽  
Pulmonary Capillary Blood ◽  
Capillary Bed ◽  
The Right ◽  
Breathing Room

Lethal gas embolism always occurs after FC 80 liquid fluorocarbon is injected intravenously (0.1 ml/kg body mass) in dogs breathing room air but not in dogs breathing oxygenated FC 80 liquid fluorocarbon. Gas embolism is not prevented in dogs that have been injected intravenously with FC 80 when they are exposed to 2 ATA (atmospheres absolute) 20% 02–80% N2, 9 ATA 5% O2–95% He, or 1 ATA 100%, O2. In dogs that die of FC 80-induced gas embolism, free gas in the right atrium contains approximately 0.5 g FC 80/liter, and Po2 and Pco2 in the gas are in equilibrium with their corresponding tensions in right atrial blood. These observations are consistent with the hypothesis that PFC 80 in alveolar gas does not equilibrate with PFC 80 (55 mmHg) in blood. The total gas tension in pulmonary capillary blood containing FC 80 and its vapor thus exceeds the total tension of alveolar gases (atmospheric pressure). Bubbles of O2, CO2, N2, FC 80, and water vapor form in the regions of the pulmonary capillary bed where the total tension of gases dissolved in blood exceeds the absolute blood pressure.

Microvascular pressure distribution in skeletal muscle and the effect of vasodilation

1975 ◽  
Vol 228 (3) ◽  
pp. 791-796 ◽  
Author(s):  
K Fronek ◽  
BW Zweifach
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Arterial Pressure ◽  
Pressure Distribution ◽  
Capillary Pressure ◽  
Systemic Arterial Pressure ◽  
Capillary Blood ◽  
Fluid Filtration ◽  
Arteriolar Resistance ◽  
Capillary Bed

In cats anesthetized with pentobarbital, 188 direct microvascular pressure and diameter measurements were made of the tenuissimus muscle. The microvascular pressure in arterioles of 70 mum in diameter or larger was proportional to the systemic arterial pressure (PA). The arterioles with diameter-s ranging from 35 to 20 mum have been shown to be the principa-l source of arteriolar resistance regulating micropressures downstream. Across the capillary bed proper, the drop in pressures was about 15% of PA. Micropressures in the smallest venules (8-15 mum) averaged 24 mmHg and reflect closely capillary blood pressure. With a background of basic microvascular data, the vasodilatory mechanism of papaverine (P) and isoproterenol (IPR) in the skeletal muscle was analyzed. Administration of IPR decreases both arteriolar and venular pressure, while P infusion decreased the pressure in arterioles wider than 20 mum in diameter; however, in smaller arterioles there was a substantial elevation in micropressure. The data establish two basically different vasodilatory effects on the terminal vasculature: one with increased capillary pressure and fluid filtration (P), a second with a decrease in capillary pressure enhancing absorption (IPR).

scholarly journals THE RELATION OF ANGIOTONIN AND L-NOREPINEPHRINE TO ESSENTIAL HYPERTENSION AS DETERMINED BY THE REACTION OF THE NAILFOLD CAPILLARY BED

1956 ◽  
Vol 103 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Sheldon E. Greisman
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Essential Hypertension ◽  
Arterial Blood Pressure ◽  
Reactive Hyperemia ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Arterial Blood ◽  
Capillary Bed ◽  
Diastolic Arterial Blood Pressure

Further evidence has been obtained that L-norepinephrine infusions markedly decreases cutaneous capillary blood flow in the nailfold. Sustained ischemia of the capillary bed occurred prior to the attainment of hypertensive diastolic arterial blood pressure levels. Corroborative evidence of this nailfold capillary ischemia was obtained from the capillary reactive hyperemia that followed the abrupt discontinuance of the L-norepinephrine infusions. The infusion of angiotonin into persons with normal blood pressure did not induce sustained ischemia of the nailfold capillary vessels, even after definite hypertensive diastolic arterial blood pressure levels were attained. Corroboration of the adequacy of nailfold capillary blood flow was obtained by noting the absence of capillary reactive hyperemia following the abrupt cessation of the angiotonin infusions. The nailfold capillary bed in persons with angiotonin-induced hypertension could not be distinguished from that of persons with essential hypertension by direct microscopic examination. During the infusion of angiotonin into subjects with normal cardiovascular systems, the reactivity of the nailfold capillary bed to circulating L-norepinephrine was significantly increased, approaching the levels found in persons with essential hypertension. From the standpoint of its effects upon the nailfold capillary bed, angiotonin, unlike L-norepinephrine, is one substance which possesses the properties required of the hypothetical humoral pressor substance of essential hypertension.

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Ocular Blood Flow ◽  
Capillary Blood ◽  
Post Treatment ◽  
Capillary Blood Flow ◽  
Doppler Imaging ◽  
Retinal Capillary

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.

Colloid Osmotic Pressure in Newborn Infants: Variations with Birth Weight, Gestational Age, Total Serum Solids, and Mean Arterial Pressure

PEDIATRICS ◽  
1981 ◽  
Vol 68 (6) ◽  
pp. 814-819
Author(s):  
Paul Y. K. Wu ◽  
Gary Rockwell ◽  
Linda Chan ◽  
Shu-Mei Wang ◽  
Vikram Udani
Keyword(s):  
Blood Pressure ◽  
Birth Weight ◽  
Osmotic Pressure ◽  
Gestational Age ◽  
Small For Gestational Age ◽  
Newborn Infants ◽  
Colloid Osmotic Pressure ◽  
Large For Gestational Age ◽  
Total Serum ◽  
Arterial Blood

Colloid osmotic pressure (COP) of blood was measured directly at birth with the Wescor membrane colloid osmometer (model 4100) in 91 appropriately grown, 11 large, and nine small for gestational age "well" newborn infants. COP correlated directly with birth weight (r = .726, P < .00001) and gestational age (r = .753, P < .00001). COP values for small for gestational age (SGA) and large for gestational age (LGA) infants were found to fall within the 95% prediction interval with regard to birth weight and gestational age for appropriate for gestational age (AGA) infants. Simultaneous measurements of COP, total serum solids, and central arterial mean blood pressure were made. The results showed that COP correlated directly with total serum solids (r = .89, P < .0001) and mean arterial blood pressure (r = .660, P < .001). Among the factors evaluated, total serum solids was the best predictor of COP.

scholarly journals Impaired Training-Induced Adaptation of Blood Pressure in COPD Patients: Implication of the Muscle Capillary Bed [Corrigendum]

2020 ◽  
Vol Volume 15 ◽  
pp. 1739-1740
Author(s):  
Fares Gouzi ◽  
Jonathan Maury ◽  
François Bughin ◽  
Marine Blaquière ◽  
Bronia Ayoub ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Copd Patients ◽  
Capillary Bed

Role of extravascular protein in capillary-tissue fluid exchange

1978 ◽  
Vol 234 (1) ◽  
pp. H52-H58
Author(s):  
E. P. Salathe ◽  
R. Venkataraman
Keyword(s):  
Mathematical Model ◽  
Perturbation Theory ◽  
Osmotic Pressure ◽  
Analytic Solutions ◽  
Tissue Fluid ◽  
Fluid Exchange ◽  
Numerical Examples ◽  
Pathological Conditions ◽  
And Diffusion

A mathematical model of capillary-tissue fluid exchange is presented. The effect of variation in plasma and interstitial osmotic pressure that occurs as a result of convection and diffusion of protein is examined. Analytic solutions to the resulting equations are obtained by using the methods of perturbation theory. It is found that fluid exchange can significantly alter the pericapillary interstitial osmotic pressure, reducing both filtration and reabsorption. Variation in plasma osmotic pressure is important only for certain pathological conditions in which excessive filtration occurs. Specific numerical examples are presented which show quantitatively the extent of these effects for various normal and pathological conditions of physiological interest.

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