Pulmonary nitric oxide in mountain dwellers

Beall, Cynthia M.; Laskowski, Daniel; Strohl, Kingman P.; Soria, Rudy; Villena, Mercedes; Vargas, Enrique; Alarcón, Ana; Gonzales, Cristina; Erzurum, Serpil C.

doi:10.1038/35106641

Cited by 217 publications

(160 citation statements)

References 11 publications

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“…An inverse relationship between SpO 2 and PAP was reported as early as 1957 at 4540m 44 50 , and blood viscosity 29 . To provide insight into this latter point, we corrected both lowlander and Sherpa PASP values to a sea level HCT (45%).…”

Section: Discussionmentioning

confidence: 94%

Chemoreceptor Responsiveness at Sea Level Does Not Predict the Pulmonary Pressure Response to High Altitude

Hoiland

Foster

Donnelly

et al. 2015

Chest

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Abstract:The hypoxic ventilatory response (HVR) at sea level (SL) is moderately predictive of the change in pulmonary artery systolic pressure (PASP) to acute normobaric hypoxia. However, because of progressive changes in the chemoreflex control of breathing and acid-base balance at high altitude (HA), HVR at SL may not predict PASP at HA. We hypothesized that resting peripheral oxyhemoglobin saturation (SpO 2 ) at HA would correlate better than HVR at SL to PASP at HA. In 20 participants at SL, we measured normobaric, isocapnic HVR (L/min·-%SpO 2 -1 ) and resting PASP using echocardiography.Both resting SpO 2 and PASP measures were repeated on day 2 (n=10), days 4-8 (n=12), and 2-3 weeks (n=8) after arrival at 5050m. These data were also collected at 5050m on life-long HA residents (Sherpa; n=21

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Section: Discussionmentioning

confidence: 94%

Chemoreceptor Responsiveness at Sea Level Does Not Predict the Pulmonary Pressure Response to High Altitude

Hoiland

Foster

Donnelly

et al. 2015

Chest

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“…The biochemical mechanisms underlying the pathogenesis of HAPH are poorly understood, but a reduction in nitric oxide (NO) production is thought to play a role [23]. Animal studies showed that the absence of endothelial NO synthase increased susceptibility to HAPH [24].…”

Section: Pathogenesismentioning

confidence: 99%

High-altitude pulmonary hypertension: Table. 1—

Xq¹,

Jing²

2009

Eur Respir Rev

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High-altitude pulmonary hypertension (HAPH) is a specific disease affecting populations that live at high elevations. The prevalence of HAPH among those residing at high altitudes needs to be further defined. Whereas reduction in nitric oxide production may be one mechanism for the development of HAPH, the roles of endothelin-1 and prostaglandin I 2 pathways in the pathogenesis of HAPH deserve further study.Although some studies have suggested that genetic factors contribute to the pathogenesis of HAPH, data published to date are insufficient for the identification of a significant number of gene polymorphims in HAPH.The clinical presentation of HAPH is nonspecific. Exertional dyspnoea is the most common symptom and signs related to right heart failure are common in late stages of HAPH. Echocardiography is the most useful screening tool and right heart catheterisation is the gold standard for the diagnosis of HAPH. The ideal management for HAPH is migration to lower altitudes. Phosphodiesterase 5 is an attractive drug target for the treatment of HAPH.In addition, acetazolamide is a promising therapeutic agent for high-altitude pulmonary hypertension. To date, no evidence has confirmed whether endothelin-receptor antagonists have efficacy in the treatment of high-altitude pulmonary hypertension.KEYWORDS: High-altitude pulmonary hypertension, hypoxia-inducible factor-1, nitric oxide, phosphodiesterase inhibitors, pulmonary vasoconstriction, right heart catheterisation H igh-altitude pulmonary hypertension (HAPH) due to chronic exposure to high altitude is a designated subset of pulmonary hypertension (PH) according to the third clinical classification of PH, which was approved during a conference in 2003 in Venice, Italy [1].It is estimated that more than 140 million people live 2,500 m above sea level, and the number of temporary visitors to mountains is close to 40 million [2,3]. Due to the substantial population exposed to the effects of high altitude, HAPH has become a public health problem in mountainous regions throughout the world. There are three specific locations where high-altitude studies have recently been performed: 1) the Himalayas of Asia; 2) the Andes of South America; and 3) the Rocky Mountains of North America. The present review will focus on the epidemiology, pathophysiology, pathogenesis, clinical characteristics and treatment of HAPH. DEFINITIONHAPH is a clinical syndrome seen in adults and children residing in high-altitude regions. As chronic mountain syndrome (CMS) is characterised by severe hypoxaemia, excessive polycythaemia and marked PH [4], HAPH is regarded as an important subset of CMS. However, the definition and diagnostic criteria of HAPH remain somewhat vague. According to the 2003 conference on PH, HAPH is classified in the third group of PH (table 1) [1]. Thus, right heart catheterisation is required to establish the diagnosis of HAPH (PH is defined by a mean pulmonary artery pressure (P pa) of .25 mmHg at rest or .30 mmHg with exercise) [5]. EPIDEMIOLOGYAlthough HAP...

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“…Four of these (CO 2 , NH 3 , acetone and isoprene) were selected based on their differing functionality and relatively high concentrations. NO was chosen in view of its effect on oxygen uptake in hypoxic conditions (Beall et al 2001). …”

Section: Introductionmentioning

confidence: 99%

Attraction of the tropical bont tick, Amblyomma variegatum , to human breath and to the breath components acetone, NO and CO 2

McMahon

Guérin

2002

Naturwissenschaften

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Ticks are of medical and veterinary importance and employ several cues in search of a host. Olfaction is one modality by which ticks locate a blood-meal and breath is the major vent of gaseous and volatile metabolites from the host that could contribute to this search. We studied the responses of a hunter tick, Amblyomma variegatum, to diluted human breath and five of its components (acetone, CO 2 , NO, isoprene and NH 3 ) while walking in an air stream on a locomotion compensator. Diluted breath elicited the greatest responses of all treatments in terms of time to onset of upwind walk, attraction, speed and local search behaviour after stimulus off. Acetone, NO and CO 2 also attracted, but with a reduced speed in the case of acetone and NO. Neither isoprene nor NH 3 induced any response. Our study indicates that breath was the most adequate stimulus tested. It also attracted two other ixodid tick species, Rhipicephalus sanguineus and Ixodes ricinus, as well as the argasid tick, Ornithodorus moubata. It appears that the evolution of resource tracking in ticks included sensory and behavioural adaptations for recognition and orientation to host metabolites that are regularly expelled in breath.

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Pulmonary nitric oxide in mountain dwellers

Cited by 217 publications

References 11 publications

Chemoreceptor Responsiveness at Sea Level Does Not Predict the Pulmonary Pressure Response to High Altitude

Chemoreceptor Responsiveness at Sea Level Does Not Predict the Pulmonary Pressure Response to High Altitude

High-altitude pulmonary hypertension: Table. 1—

Attraction of the tropical bont tick, Amblyomma variegatum , to human breath and to the breath components acetone, NO and CO 2

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