scholarly journals Angiotensin-Converting Enzyme Genotype and Arterial Oxygen Saturation at High Altitude in Peruvian Quechua

2008 ◽  
Vol 9 (2) ◽  
pp. 167-178 ◽  
Author(s):  
Abigail W. Bigham ◽  
Melisa Kiyamu ◽  
Fabiola León-Velarde ◽  
Esteban J. Parra ◽  
Maria Rivera-Ch ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Oxygen Saturation ◽  
High Altitude ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme Genotype

Angiotensin Converting Enzyme Response to Hypoxia in Man: Its Role in Altitude Acclimatization

1984 ◽  
Vol 67 (4) ◽  
pp. 453-456 ◽  
Author(s):  
J. S. Milledge ◽  
D. M. Catley
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Oxygen Saturation ◽  
Human Subjects ◽  
Arterial Oxygen Saturation ◽  
Venous Blood ◽  
Acute Mountain Sickness ◽  
Arterial Oxygen ◽  
Converting Enzyme ◽  
Ace Activity ◽  
Mountain Sickness

1. The response of serum angiotensin converting enzyme (ACE) activity to three grades of hypoxia was studied in two groups of human subjects. Hypoxic gas mixtures having oxygen concentrations of 14, 12.6 and 10.4% were breathed successively for a period of 10 min at each concentration. Venous blood was sampled at the end of each of the three periods and arterial oxygen saturation was recorded throughout the experiment. 2. The subjects were selected as being ‘good’ or ‘poor’ acclimatizers according to their history of acute mountain sickness. There were five subjects in each group. 3. Hypoxia resulted in a reduction in ACE activity in both groups, the reduction being linear with respect to arterial oxygen saturation. 4. The reduction in ACE activity was greater in the good acclimatizer group as shown by a significantly greater slope of the response line of ACE activity to arterial oxygen saturation. 5. The significance of this finding in relation to the mechanism underlying acute mountain sickness is discussed.

Angiotensin-Converting Enzyme Genotype and Successful Ascent to Extreme High Altitude

2007 ◽  
Vol 8 (4) ◽  
pp. 278-285 ◽  
Author(s):  
Julian Thompson ◽  
James Raitt ◽  
Lynn Hutchings ◽  
Fotios Drenos ◽  
Eirik Bjargo ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
High Altitude ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme Genotype

P6480Asymmetric dimethylarginine (ADMA) predicts altitude-associated hypoxic pulmonary arterial hypertension

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
R H Boeger ◽  
P Siques ◽  
J Brito ◽  
E Schwedhelm ◽  
E Pena ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Logistic Regression ◽  
Oxygen Saturation ◽  
High Altitude ◽  
Sea Level ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Pulmonary Arterial

Abstract Prolonged exposure to altitude-associated chronic hypoxia (CH) may cause high altitude pulmonary hypertension (HAPH). Chronic intermittent hypobaric hypoxia (CIH) occurs in individuals who commute between sea level and high altitude. CIH is associated with repetitive acute hypoxic acclimatization and conveys the long-term risk of HAPH. As nitric oxide (NO) is an important regulator of systemic and pulmonary vascular tone and asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthesis that increases in hypoxia, we aimed to investigate whether ADMA predicts the incidence of HAPH among Chilean frontiers personnel exposed to six months of CIH. We performed a prospective study of 123 healthy male subjects who were subjected to CIH (5 days at appr. 3,550 m, followed by 2 days at sea level) for six months. ADMA, SDMA, L-arginine, arterial oxygen saturation, systemic arterial blood pressure, and haematocrit were measured at baseline and at months 1, 4, and 6 at high altitude. Acclimatization to high altitude was determined using the Lake Louise Score and the presence of acute mountain sickness (AMS). Echocardiography was performed after six months of CIH in a subgroup of 43 individuals with either good (n=23) or poor (n=20) aclimatization to altitude, respectively. Logistic regression was used to assess the association of biomarkers with HAPH. 100 study participants aged 18.3±1.3 years with complete data sets were included in the final analysis. Arterial oxygen saturation decreased upon the first ascent to altitude and plateaued at about 90% during the further course of the study. Haematocrit increased to about 47% after one month and remained stable thereafter. ADMA continuously increased and SDMA decreased during the study course, whilst L-arginine levels showed no distinct pattern. The incidence of AMS and the Lake Louise Score were high after the first ascent (53 and 3.1±2.4, respectively) and at one month of CIH (47 and 3.0±2.6, respectively), but decreased to 20 and 1.4±2.0 at month 6, respectively (both p<0.001 for trend). In echocardiography, 18 participants (42%) showed a mean pulmonary arterial pressure (mPAP) greater than 25 mm Hg (mean ± SD, 30.4±3.9 mm Hg), out of which 9 (21%) were classified as HAPH (mPAP ≥30 mm Hg; mean ± SD, 33.9±2.2 mm Hg). Baseline ADMA, but not SDMA, was significantly associated with mPAP at month 6 in univariate logistic regression analysis (R = 0.413; p=0.007). In ROC analysis, a cut-off for baseline ADMA of 0.665 μmol/l was determined as the optimal cut-off level to predict HAPH (mPAP >30 mm Hg) with a sensitivity of 100% and a specificity of 63.6%. ADMA concentration increases during long-term CIH. It is an independent predictive biomarker for the incidence of HAPH. SDMA concentration decreases during CIH and shows no association with HAPH. Our data support a role of impaired NO-mediated pulmonary vasodilation in the pathogenesis of high altitude pulmonary hypertension. Acknowledgement/Funding CONICYT/FONDEF/FONIS Sa 09I20007; FIC Tarapaca BIP 30477541-0; BMBF grant 01DN17046 (DECIPHER); Georg & Jürgen Rickertsen Foundation, Hamburg

scholarly journals Associations between arterial oxygen saturation, body size and limb measurements among high-altitude andean children

2013 ◽  
Vol 25 (5) ◽  
pp. 629-636 ◽  
Author(s):  
Emma Pomeroy ◽  
Jay T. Stock ◽  
Sanja Stanojevic ◽  
J. Jaime Miranda ◽  
Tim J. Cole ◽  
...  
Keyword(s):  
Body Size ◽  
Oxygen Saturation ◽  
High Altitude ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen

scholarly journals Pulmonary artery pressure and arterial oxygen saturation in people living at high or low altitude: systematic review and meta-analysis

2016 ◽  
Vol 121 (5) ◽  
pp. 1151-1159 ◽  
Author(s):  
Rodrigo Soria ◽  
Matthias Egger ◽  
Urs Scherrer ◽  
Nicole Bender ◽  
Stefano F. Rimoldi
Keyword(s):  
Systematic Review ◽  
Pulmonary Artery ◽  
Oxygen Saturation ◽  
High Altitude ◽  
Pulmonary Artery Pressure ◽  
Meta Analysis ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Low Altitude ◽  
Apparently Healthy

More than 140 million people are living at high altitude worldwide. An increase of pulmonary artery pressure (PAP) is a hallmark of high-altitude exposure and, if pronounced, may be associated with important morbidity and mortality. Surprisingly, there is little information on the usual PAP in high-altitude populations. We, therefore, conducted a systematic review (MEDLINE and EMBASE) and meta-analysis of studies published (in English or Spanish) between 2000 and 2015 on echocardiographic estimations of PAP and measurements of arterial oxygen saturation in apparently healthy participants from general populations of high-altitude dwellers (>2,500 m). For comparison, we similarly analyzed data published on these variables during the same period for populations living at low altitude. Twelve high-altitude studies comprising 834 participants and 18 low-altitude studies (710 participants) fulfilled the inclusion criteria. All but one high-altitude studies were performed between 3,600 and 4,350 m. The combined mean systolic PAP (right ventricular-to-right atrial pressure gradient) at high altitude [25.3 mmHg, 95% confidence interval (CI) 24.0, 26.7], as expected was significantly (P < 0.001) higher than at low altitude (18.4 mmHg, 95% CI 17.1,19.7), and arterial oxygen saturation was significantly lower (90.4%, 95% CI 89.3, 91.5) than at low altitude (98.1%; 95% CI 97.7, 98.4). These findings indicate that at an altitude where the very large majority of high-altitude populations are living, pulmonary hypertension appears to be rare. The reference values and distributions for PAP and arterial oxygen saturation in apparently healthy high-altitude dwellers provided by this meta-analysis will be useful to future studies on the adjustments to high altitude in humans.

scholarly journals Relationship Between Arterial Oxygen Saturation and Hematocrit, and Effect of Slow Deep Breathing on Oxygen Saturation in Himalayan High Altitude Populations

2013 ◽  
Vol 10 (3) ◽  
pp. 30-34 ◽  
Author(s):  
Ojashwi Nepal ◽  
BR Pokharel ◽  
K Khanal ◽  
SL Mallik ◽  
BK Kapoor ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
High Altitude ◽  
Carrying Capacity ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
P Value ◽  
Deep Breathing ◽  
Cross Sectional ◽  
Lower Altitude ◽  
Oxygen Carrying Capacity

Background The oxygen saturation of haemoglobin is reduced in high altitude-living organisms. Increase in the hematocrit is responsible for rise in the hemoglobin concentration so that the oxygen carrying capacity in the hypobaric hypoxic subject is elevated. Objectives To compare two different high altitude populations, in order to study the relationship between arterial oxygen saturation and hematocrit. Methods lIn the cross-sectional study of two populations residing at altitude of 2800 m and 3760 m are compared for the difference in hematocrit. The oxygen carrying capacity of arterial haemoglobin (SaO2) is determined by pulse oximetry. The sample is drawn from the natives of two small villages, Thini at Jomsom (2800 m) and Jharkot (3760 m) in Mustang district of Nepal. The natives at 2800 m are termed as lower high altitude population and local residents at 3760 m are said to be higher altitude population in this study. The sample blood was drawn by venipuncture and packed cell volume was determined by Wintrobe’s method. Results The hematocrit obtained from 3760 m altitude population and the lower high altitude population at altitude of 2800 m differ significantly with the p value < 0.0001and the SaO2 in both the population fails to show any difference with p value > 0.05. Deep breathing exercise in these populations however increased SaO2 significantly. Conclusion The higher altitude natives have greater arterial oxygen saturation than lower altitude population which is due to rise in red cell concentration. The slow deep breathing raises oxygen saturation irrespective of altitude. Kathmandu University Medical Journal | VOL.10 | NO. 3 | ISSUE 39 | JUL- SEP 2012 | Page 30-34 DOI: http://dx.doi.org/10.3126/kumj.v10i3.8014

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