Functional capacities of lungs and thorax in beagles after prolonged residence at 3,100 m

1985 ◽  
Vol 59 (6) ◽  
pp. 1773-1782 ◽  
Author(s):  
R. L. Johnson ◽  
S. S. Cassidy ◽  
R. F. Grover ◽  
J. E. Schutte ◽  
R. H. Epstein
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Pulmonary Blood Flow ◽  
Lung Volumes ◽  
Anatomical Distribution ◽  
X Ray ◽  
Control Subjects ◽  
X Ray Computed ◽  
Functional Capacities ◽  
And Control

Functional capacities of the lungs and thorax in beagles taken to high altitude as adults for 33 mo or in beagles raised from puppies at high altitude were compared with functional capacities in corresponding sets of beagles kept simultaneously at sea level. Comparisons were made after reacclimatization to sea level. Lung volumes, airway pressures, esophageal pressures, CO diffusing capacities (DLCO), pulmonary blood flow, and lung tissue volume (Vt) were measured by a rebreathing technique at inspired volumes ranging from 15 to 90 ml/kg. In beagles raised from puppies we measured anatomical distribution of intrathoracic air and tissue using X-ray computed tomography at transpulmonary pressures of 20 cm H2O. Lung and thoracic distensibility, DLCO, and Vt were not different between beagles that had been kept at high altitude for 33 mo as adults and control subjects kept simultaneously at sea level. Lung distensibility, DLCO, and Vt were significantly greater in beagles raised at high altitude than control subjects raised simultaneously at sea level. Thoracic distensibility was not increased in beagles raised at high altitude; the larger lung volume was accommodated by a lower diaphragm, not a larger rib cage.

Effects of erythrocyte infusion on VO2max at high altitude

1996 ◽  
Vol 81 (1) ◽  
pp. 252-259 ◽  
Author(s):  
A. J. Young ◽  
M. N. Sawka ◽  
S. R. Muza ◽  
R. Boushel ◽  
T. Lyons ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Treadmill Running ◽  
Control Group ◽  
O2 Uptake ◽  
Control Subjects ◽  
And Control ◽  
Experimental Group

This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P < 0.01) arterial hematocrit, hemoglobin concentration, and arterial O2 content in the erythrocyte-infused subjects. By HA9, there were no longer any differences in hematocrit, hemoglobin concentration, or arterial O2 content between groups. No change in VO2max occurred between HA1 and HA9 for either group. Thus, despite increasing arterial O2-carrying capacity, autologous erythrocyte infusion did not ameliorate the decrement in VO2max at 4,300-m altitude.

Comparison of Body Composition Study by Dual-Energy X-Ray Absorptiometry (DEXA) in Familial Partial Lipodystrophies and Control Subjects

2011 ◽  
pp. P1-457-P1-457
Author(s):  
Cynthia Melissa Valerio ◽  
Lenita Zajdenverg ◽  
Jose Egidio Paulo Oliveira ◽  
Patricia Mory ◽  
Regina Moises ◽  
...  
Keyword(s):  
Body Composition ◽  
Dual Energy ◽  
X Ray ◽  
Control Subjects ◽  
Body Composition Study ◽  
Composition Study ◽  
And Control

Anatomical distribution of sacroiliac joint MRI lesions in axial spondyloarthritis and control subjects

2020 ◽  
Author(s):  
Sengül Seven ◽  
Mikkel Østergaard ◽  
Lone Morsel‐Carlsen ◽  
Inge J Sørensen ◽  
Birthe Bonde ◽  
...  
Keyword(s):  
Sacroiliac Joint ◽  
Axial Spondyloarthritis ◽  
Anatomical Distribution ◽  
Control Subjects ◽  
And Control

Nitric oxide and cardiopulmonary hemodynamics in Tibetan highlanders

2005 ◽  
Vol 99 (5) ◽  
pp. 1796-1801 ◽  
Author(s):  
Brian D. Hoit ◽  
Nancy D. Dalton ◽  
Serpil C. Erzurum ◽  
Daniel Laskowski ◽  
Kingman P. Strohl ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Pulmonary Artery ◽  
High Altitude ◽  
Sea Level ◽  
Pulmonary Blood Flow ◽  
Geometric Mean ◽  
Systolic Pressure ◽  
Pulmonary Artery Systolic Pressure ◽  
Exhaled No

When O2 availability is reduced unavoidably, as it is at high altitude, a potential mechanism to improve O2 delivery to tissues is an increase in blood flow. Nitric oxide (NO) regulates blood vessel diameter and can influence blood flow. This field study of intrapopulation variation at high altitude tested the hypothesis that the level of exhaled NO (a summary measure of pulmonary synthesis, consumption, and transfer from cells in the airway) is directly proportional to pulmonary, and thus systemic, blood flow. Twenty Tibetan male and 37 female healthy, nonsmoking, native residents at 4,200 m (13,900 ft), with an average O2 saturation of hemoglobin of 85%, participated in the study. The geometric mean partial pressure of NO exhaled at a flow of 17 ml/s was 23.4 nmHg, significantly lower than that of a sea-level reference group. However, the rate of NO transfer out of the airway wall was seven times higher than at sea level, which implied the potential for vasodilation of the pulmonary blood vessels. Mean pulmonary blood flow (measured by cardiac index) was 2.7 ± 0.1 (SE) l/min, and mean pulmonary artery systolic pressure was 31.4 ± 0.9 (SE) mmHg. Higher exhaled NO was associated with higher pulmonary blood flow; yet there was no associated increase in pulmonary artery systolic pressure. The results suggest that NO in the lung may play a key beneficial role in allowing Tibetans at 4,200 m to compensate for ambient hypoxia with higher pulmonary blood flow and O2 delivery without the consequences of higher pulmonary arterial pressure.

scholarly journals Susceptibility to high-altitude pulmonary edema is associated with increased pulmonary arterial stiffness during exercise

2020 ◽  
Vol 128 (3) ◽  
pp. 514-522
Author(s):  
A. Mulchrone ◽  
H. Moulton ◽  
M. W. Eldridge ◽  
N. C. Chesler
Keyword(s):  
Arterial Stiffness ◽  
Pulmonary Edema ◽  
High Altitude ◽  
Sea Level ◽  
Published Data ◽  
Control Subjects ◽  
High Altitude Pulmonary Edema ◽  
Artery Stiffness ◽  
Response To Exercise ◽  
Distal Artery

High-altitude pulmonary edema (HAPE), a reversible form of capillary leak, is a common consequence of rapid ascension to high altitude and a major cause of death related to high-altitude exposure. Individuals with a prior history of HAPE are more susceptible to future episodes, but the underlying risk factors remain uncertain. Previous studies have shown that HAPE-susceptible subjects have an exaggerated pulmonary vasoreactivity to acute hypoxia, but incomplete data are available regarding their vascular response to exercise. To examine this, seven HAPE-susceptible subjects and nine control subjects (HAPE-resistant) were studied at rest and during incremental exercise at sea level and at 3,810 m altitude. Studies were conducted in both normoxic (inspired Po2 = 148 Torr) and hypoxic (inspired Po2 = 91 Torr) conditions at each location. Here, we report an expanded analysis of previously published data, including a distensible vessel model that showed that HAPE-susceptible subjects had significantly reduced small distal artery distensibility at sea level compared with HAPE-resistant control subjects [0.011 ± 0.001 vs. 0.021 ± 0.002 mmHg−1; P < 0.001). Moreover, HAPE-susceptible subjects demonstrated constant distensibility over all conditions, suggesting that distal arteries are maximally distended at rest. Consistent with having increased distal artery stiffness, HAPE-susceptible subjects had greater increases in pulmonary artery pulse pressure with exercise, which suggests increased proximal artery stiffness. In summary, HAPE-susceptible subjects have exercise-induced increases in proximal artery stiffness and baseline increases in distal artery stiffness, suggesting increased pulsatile load on the right ventricle. NEW & NOTEWORTHY In comparison to subjects who appear resistant to high-altitude pulmonary edema, those previously symptomatic show greater increases in large and small artery stiffness in response to exercise. These differences in arterial stiffness may be a risk factor for the development of high-altitude pulmonary edema or evidence that consequences of high-altitude pulmonary edema are long-lasting after return to sea level.

Alveolar P CO 2 and P O 2 of high-altitude natives living at sea level

1996 ◽  
Vol 81 (4) ◽  
pp. 1605-1609 ◽  
Author(s):  
Fabiola León-Velarde ◽  
Manuel Vargas ◽  
Carlos Monge-C. ◽  
Robert W. Torrance ◽  
Peter A. Robbins
Keyword(s):  
Confidence Interval ◽  
High Altitude ◽  
Sea Level ◽  
Average Difference ◽  
Control Subjects ◽  
High Altitude Natives ◽  
End Tidal

León-Velarde, Fabiola, Manuel Vargas, Carlos Monge-C., Robert W. Torrance, and Peter A. Robbins. Alveolar[Formula: see text] and[Formula: see text] of high-altitude natives living at sea level. J. Appl. Physiol. 81(4): 1605–1609, 1996.—This study was designed to determine whether subjects born at high altitude (HA; 2,000 m or above) who subsequently move to near sea level (SL) develop end-tidal [Formula: see text]([Formula: see text]) and[Formula: see text]([Formula: see text]) values that equal those of SL natives living near SL. A total of 108 male HA natives living near SL were identified by survey of a district in Lima, Peru, and a further 108 male SL natives from the same district were identified as control subjects. Of these subjects, satisfactory data for inclusion in the study were obtained from 93 HA and 82 SL subjects. Mean [Formula: see text] and[Formula: see text] values were 37.7 ± 2.5 (SD) and 104.7 ± 3.2 Torr, respectively, in HA subjects and 37.7 ± 2.2 and 104.8 ± 3.0 Torr, respectively, in SL subjects. The average difference between SL natives and HA natives for[Formula: see text] was 0.07 Torr (−0.64 to 0.78; 95% confidence interval) and for[Formula: see text] was 0.05 Torr (−0.89 to 0.99, 95% confidence interval). The average age and weight of the SL and HA subjects did not differ, but the HA subjects were shorter and tended to have larger vital capacities, consistent with their origin at HA. We conclude that the[Formula: see text] and[Formula: see text] near SL of SL natives and HA natives do not differ.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

The Effects of a Neutral Stimulus (Buzzer) on Motor Responses and Disfluencies in Normal Speakers

1969 ◽  
Vol 12 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Richard R. Martin ◽  
Gerald M. Siegel
Keyword(s):  
College Students ◽  
Neutral Stimulus ◽  
Motor Responses ◽  
Control Subjects ◽  
And Control ◽  
Speaking Task

Seventy-two college students were divided into three groups: Button Push-Speech (BP-S), Speech-Button Push (S-BP), and Control. BP-S subjects pushed one of two buttons on signal for 8 min. During the last 4 min, depression of the criterion button caused a buzzer to sound. After the button-push task, subjects spoke spontaneously for 30 min. During the last 20 min, the buzzer was presented contingent upon each disfluency. S-BP subjects were run under the same procedures, but the order of button-push and speech tasks was reversed. Control subjects followed the same procedures as S-BP subjects, but no buzzer signal was presented at any time. Both S-BP and BP-S subjects emitted significantly fewer disfluencies during the last 20 min (Conditioning) than during the first 10 min (Baserate) of the speaking task. The frequency of disfluencies for Control subjects did not change significantly from Baserate to Conditioning. In none of the three groups did the frequency of pushes on the criterion button change significantly from minute to minute throughout the 8-min button-push session.

X-Ray Computed Tomography of Ultralightweight Metals

1999 ◽  
Vol 11 (1) ◽  
pp. 199-211
Author(s):  
J. M. Winter ◽  
R. E. Green ◽  
A. M. Waters ◽  
W. H. Green
Keyword(s):  
Computed Tomography ◽  
X Ray ◽  
X Ray Computed
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