Ischemic changes in exercise ECG in a hypertensive subject acutely exposed to high altitude. Possible role of a high-altitude induced imbalance in myocardial oxygen supply–demand

2014 ◽  
Vol 171 (3) ◽  
pp. e100-e102 ◽  
Author(s):  
Sergio Caravita ◽  
Andrea Faini ◽  
Grzegorz Bilo ◽  
Miriam Revera ◽  
Andrea Giuliano ◽  
...  
Keyword(s):  
High Altitude ◽  
Oxygen Supply ◽  
Hypertensive Subject ◽  
Exercise Ecg ◽  
Myocardial Oxygen Supply

scholarly journals Role of myoglobin in the oxygen supply to red skeletal muscle

1975 ◽  
Vol 250 (23) ◽  
pp. 9038-9043
Author(s):  
BA Wittenberg ◽  
JB Wittenberg ◽  
PR Caldwell
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Supply

scholarly journals Changes in Subendocardial Viability Ratio With Acute High-Altitude Exposure and Protective Role of Acetazolamide

Hypertension ◽  
2013 ◽  
Vol 61 (4) ◽  
pp. 793-799 ◽  
Author(s):  
Paolo Salvi ◽  
Miriam Revera ◽  
Andrea Faini ◽  
Andrea Giuliano ◽  
Francesca Gregorini ◽  
...  
Keyword(s):  
High Altitude ◽  
Protective Role ◽  
Altitude Exposure ◽  
Subendocardial Viability Ratio

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

Role of Neuropeptide Y and Galanin in High Altitude Induced Anorexia in Rats

2001 ◽  
Vol 4 (4) ◽  
pp. 323-331 ◽  
Author(s):  
S.N. Singh ◽  
P. Vats ◽  
Radhey Shyam ◽  
S. Suri ◽  
M.M.L. Kumria ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
High Altitude

910 ESTIMATED MYOCARDIAL OXYGEN SUPPLY TO DEMAND RATIO DURING BILATERAL ARM RESISTANCE EXERCISES AND ARM ERGOMETRY

1994 ◽  
Vol 26 (Supplement) ◽  
pp. S162
Author(s):  
J. L. O??Brien ◽  
A. L. Hicks ◽  
N. McCartney ◽  
D. McConachie ◽  
J. D. MacDougall ◽  
...  
Keyword(s):  
Oxygen Supply ◽  
Arm Ergometry ◽  
Resistance Exercises ◽  
Myocardial Oxygen Supply

Role of Rho kinases in PKG-mediated relaxation of pulmonary arteries of fetal lambs exposed to chronic high altitude hypoxia

2007 ◽  
Vol 292 (3) ◽  
pp. L678-L684 ◽  
Author(s):  
Yuansheng Gao ◽  
Ada D. Portugal ◽  
Sewite Negash ◽  
Weilin Zhou ◽  
Lawrence D. Longo ◽  
...  
Keyword(s):  
High Altitude ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Regulatory Subunit ◽  
Fourth Generation ◽  
Minor Effect ◽  
Altitude Hypoxia ◽  
High Altitude Hypoxia ◽  
Rock Activity

An increase in Rho kinase (ROCK) activity is implicated in chronic hypoxia-induced pulmonary hypertension. In the present study, we determined the role of ROCKs in cGMP-dependent protein kinase (PKG)-mediated pulmonary vasodilation of fetal lambs exposed to chronic hypoxia. Fourth generation pulmonary arteries were isolated from near-term fetuses (∼140 days of gestation) delivered from ewes exposed to chronic high altitude hypoxia for ∼110 days and from control ewes. In vessels constricted to endothelin-1, 8-bromoguanosine-cGMP (8-Br-cGMP) caused a smaller relaxation in chronically hypoxic (CH) vessels compared with controls. Rp-8-Br-PET-cGMPS, a PKG inhibitor, attenuated relaxation to 8-Br-cGMP in control vessels to a greater extent than in CH vessels. Y-27632, a ROCK inhibitor, significantly potentiated 8-Br-cGMP-induced relaxation of CH vessels and had only a minor effect in control vessels. The expression of PKG was increased but was not accompanied with an increase in the activity of the enzyme in CH vessels. The expression of type II ROCK and activity of ROCKs were increased in CH vessels. The phosphorylation of threonine (Thr)696 and Thr850 of the regulatory subunit MYPT1 of myosin light chain phosphatase was inhibited by 8-Br-cGMP to a lesser extent in CH vessels than in controls. The difference was eliminated by Y-27632. These results suggest that chronic hypoxia in utero attenuates PKG-mediated relaxation in pulmonary arteries, partly due to inhibition of PKG activity and partly due to enhanced ROCK activity. Increased ROCK activity may inhibit PKG action through increased phosphorylation of MYPT1 at Thr696 and Thr850.

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