scholarly journals Effect Of Heat Acclimation-induced Plasma Volume Expansion On Arterial Oxygen Content During Exposure To Hypobaric Hypoxia

2020 ◽  
Vol 52 (7S) ◽  
pp. 191-191
Author(s):  
Myra L. Jones ◽  
Roy M. Salgado
Keyword(s):  
Oxygen Content ◽  
Plasma Volume ◽  
Hypobaric Hypoxia ◽  
Volume Expansion ◽  
Heat Acclimation ◽  
Arterial Oxygen ◽  
Plasma Volume Expansion ◽  
Arterial Oxygen Content

Physiological and hematologic responses to summer and winter dry-heat acclimation

1981 ◽  
Vol 50 (4) ◽  
pp. 792-798 ◽  
Author(s):  
Y. Shapiro ◽  
R. W. Hubbard ◽  
C. M. Kimbrough ◽  
K. B. Pandolf
Keyword(s):  
Cell Volume ◽  
Plasma Volume ◽  
Volume Expansion ◽  
Sweat Rate ◽  
Heat Acclimation ◽  
Red Cell ◽  
Plasma Volume Expansion ◽  
Set Point ◽  
Dry Heat ◽  
C 30

Differences between acclimation to heat at the end of winter (W) and at the end of summer (S) were studied on the same eight male volunteers. Subjects were exposed to 40 degrees C, 30% rh for 10 consecutive days on two separate occasions approximately 5 mo apart (S and W). Daily exposures lasted 120 min: 10 min rest, 50 min walking 1.34 m . s-1 on the level, 10 min rest, 50 min walking. During W acclimation, rectal temperature (Tre) and heart rate (HR) decreased, sweat rate (msw) remained unchanged, and plasma and red cell volume of the blood expanded. During S acclimation, HR decreased while Tre and msw remained unchanged, and plasma volume increased. The Tre of the acclimated subjects remained higher in W, and the msw lower, than in S. It was concluded that acclimation does not totally eliminate the seasonal differences in thermoregulatory set point and sweating sensitivity. Further, acclimation to a more severe heat did not lower the thermoregulatory set point that was achieved by natural acclimatization to a milder heat but affected the cardiovascular adjustment and caused greater plasma volume expansion. W acclimation caused both plasma and blood cell volume expansion, whereas S acclimation affected only plasma volume.

Endothelial function and shear stress in hypobaric hypoxia: time course and impact of plasma volume expansion in men

2020 ◽  
Vol 319 (5) ◽  
pp. H980-H994
Author(s):  
Joshua C. Tremblay ◽  
Philip N. Ainslie ◽  
Rachel Turner ◽  
Hannes Gatterer ◽  
Maja Schlittler ◽  
...  
Keyword(s):  
Shear Stress ◽  
Endothelial Function ◽  
Plasma Volume ◽  
Blood Viscosity ◽  
Hypobaric Hypoxia ◽  
Volume Expansion ◽  
Hypoxic Exposure ◽  
Flow Mediated Dilation ◽  
Handgrip Exercise ◽  
Plasma Volume Expansion

Using a normoxic crossover study design, we examined the impact of hypobaric hypoxia (4 days; altitude equivalent, 3,500 m) and hemoconcentration on blood viscosity, shear stress, and endothelial function. Blood viscosity increased during the hypoxic exposure and was accompanied by elevated resting and exercising arterial shear stress. Flow-mediated dilation stimulated by reactive hyperemia and handgrip exercise was preserved throughout the hypoxic exposure. Plasma volume expansion reversed the hypoxia-associated hemoconcentration and selectively increased handgrip exercise flow-mediated dilation.

Effects of Long-term Nitric Oxide Synthesis Inhibition on Plasma Volume Expansion and Fetal Growth in the Pregnant Rat

Hypertension ◽  
1995 ◽  
Vol 26 (6) ◽  
pp. 1019-1023 ◽  
Author(s):  
Sofía P. Salas ◽  
Fernando Altermatt ◽  
Mauricio Campos ◽  
Andrea Giacaman ◽  
Pedro Rosso
Keyword(s):  
Nitric Oxide ◽  
Fetal Growth ◽  
Plasma Volume ◽  
Volume Expansion ◽  
Nitric Oxide Synthesis ◽  
Plasma Volume Expansion ◽  
Pregnant Rat ◽  
Synthesis Inhibition

Blood flow to fetal organs as a function of arterial oxygen content

1979 ◽  
Vol 135 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Louis L.H. Peeters ◽  
Roger E. Sheldon ◽  
M. Douglas Jones ◽  
Edgar L. Makowski ◽  
Giacomo Meschia
Keyword(s):  
Blood Flow ◽  
Oxygen Content ◽  
Arterial Oxygen ◽  
Arterial Oxygen Content ◽  
Fetal Organs

scholarly journals Increased susceptibility of db/db mice to rosiglitazone-induced plasma volume expansion: role of dysregulation of renal water transporters

2013 ◽  
Vol 305 (10) ◽  
pp. F1491-F1497 ◽  
Author(s):  
Li Zhou ◽  
Gang Liu ◽  
Zhanjun Jia ◽  
Kevin T. Yang ◽  
Ying Sun ◽  
...  
Keyword(s):  
Plasma Volume ◽  
Volume Expansion ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Underlying Mechanism ◽  
Fluid Retention ◽  
Receptor Subtype ◽  
Fluorescent Nanoparticles ◽  
Peroxisome Proliferator ◽  
Plasma Volume Expansion

Thiazolidinediones (TZDs), which are synthetic peroxisome proliferator-activated receptor subtype-γ (PPARγ), agonists are highly effective for treatment of type 2 diabetes. However, the side effect of fluid retention has significantly limited their application. Most of the previous studies addressing TZD-induced fluid retention employed healthy animals. The underlying mechanism of this phenomenon is still incompletely understood, particularly in the setting of disease state. The present study was undertaken to examine rosiglitazone (RGZ)-induced fluid retention in db/db mice and to further investigate the underlying mechanism. In response to RGZ treatment, db/db mice exhibited an accelerated plasma volume expansion as assessed by hematocrit (Hct) and fluorescent nanoparticles, in parallel with a greater increase in body weight, compared with lean controls. In response to RGZ-induced fluid retention, urinary Na+ excretion and urine volume were significantly increased in lean mice. In contrast, the natriuretic and diuretic responses were significantly blunted in db/db mice. RGZ db/db mice exhibited a parallel decrease in plasma Na+ concentration and plasma osmolality, contrasting to unchanged levels in lean controls. Imunoblotting analysis showed downregulation of renal aquaporin (AQP) 2 expression in response to RGZ treatment in lean mice but not in db/db mice. Renal AQP3 protein expression was unaffected by RGZ treatment in lean mice but was elevated in db/db mice. In contrast, the expression of Na+/H+ exchanger-3 (NHE3) and NKCC2 was unchanged in either mouse strain. Together these results suggest that compared with the lean controls, db/db mice exhibited accelerated plasma volume expansion that was in part due to the inappropriate response of renal water transporters.

Exercise stroke volume relative to plasma-volume expansion

1988 ◽  
Vol 64 (1) ◽  
pp. 404-408 ◽  
Author(s):  
M. K. Hopper ◽  
A. R. Coggan ◽  
E. F. Coyle
Keyword(s):  
Stroke Volume ◽  
Plasma Volume ◽  
Volume Expansion ◽  
Peripheral Resistance ◽  
Submaximal Exercise ◽  
Upright Position ◽  
Plasma Volume Expansion ◽  
Trained Subjects ◽  
The Difference ◽  
Dextran Solution

The effects of plasma-volume (PV) expansion on stroke volume (SV) (CO2 rebreathing) during submaximal exercise were determined. Intravenous infusion of 403 +/- 21 ml of a 6% dextran solution before exercise in the upright position increased SV 11% (i.e., 130 +/- 6 to 144 +/- 5 ml; P less than 0.05) in untrained males (n = 7). Further PV expansion (i.e., 706 +/- 43 ml) did not result in a further increase in SV (i.e., 145 +/- 4 ml). SV was somewhat higher during supine compared with upright exercise when blood volume (BV) was normal (i.e., 138 +/- 8 vs. 130 +/- 6 ml; P = 0.08). PV expansion also increased SV during exercise in the supine position (i.e., 138 +/- 8 to 150 +/- 8 ml; P less than 0.05). In contrast to these observations in untrained men, PV expansion of endurance-trained men (n = 10), who were naturally PV expanded, did not increase SV during exercise in the upright or supine positions. When BV in the untrained men was increased to match that of the endurance-trained subjects, SV was observed to be 15% higher (165 +/- 7 vs. 144 +/- 5 ml; P less than 0.05), whereas mean blood pressure and total peripheral resistance were significantly lower (P less than 0.05) in the trained compared with untrained subjects during upright exercise at a similar heart rate. The present findings indicate that exercise SV in untrained men is preload dependent and that increases in exercise SV occur in response to the first 400 ml of PV expansion. It appears that approximately one-half of the difference in SV normally observed between untrained and highly endurance-trained men during upright exercise is due to a suboptimal BV in the untrained men.

Cardiovascular and Respiratory Changes During Heat Stress in Rainbow Trout (Salmo Gairdneri)

1973 ◽  
Vol 59 (2) ◽  
pp. 323-338 ◽  
Author(s):  
ALAN G. HEATH ◽  
G. M. HUGHES
Keyword(s):  
Oxygen Content ◽  
Oxygen Demand ◽  
Heart Beat ◽  
Arterial Oxygen ◽  
Salmo Gairdneri ◽  
Steady Increase ◽  
Limiting Factor ◽  
Arterial Oxygen Content ◽  
Ventilatory Frequency ◽  
Increasing Temperature

1. Trout were subjected to a steady increase in water temperature (1.5 °C/h) from 15 °C until death occurred, while several respiratory and cardiovascular parameters were monitored. 2. Oxygen consumption increased during the warming (Q10 = 2.35 between 16 and 20 °C). At the higher temperatures the increase was more marked (Q10 =4.96 between 20 and 26 °C). 3. Ventilatory frequency increased during the rising temperature with a general levelling off observed above 23 °C. The amplitude of the pressure changes in the buccal and opercular cavities increased more than did the ventilatory frequency. Further analysis of the differential pressure across the gills suggests that the adjustment of respiratory pumping to the increased oxygen demand is predominantly in the volume pumped per stroke (cycle). 4. Heart rate rose steadily with the increasing temperature until about 24-25 °C, when a bradycardia usually became evident. Synchrony between the heart beat and the respiratory pumps was observed in some preparations at the higher temperatures. 5. Blood pressure increases during the warming were more marked in the ventral aorta than in the dorsal aorta. At the highest temperatures, abnormal cardiac cycles were frequently observed. 6. Arterial oxygen content declined slightly during warming and venous oxygen content dropped to zero above 23 °C. 7. It is suggested that cardiovascular adjustments may be a limiting factor in this type of stress.

Sign in / Sign up

Export Citation Format

Share Document