Abstract
Editorials
Special Topic: The Many Faces of Hypoxia
Each year we highlight a special topic in one issue of High Altitude Medicine & Biology. This year's topic, The Many Faces of Hypoxia, emphasizes some of the extraordinary changes in our discipline following the discovery of hypoxia inducible factors.
IX World Congress on High Altitude Medicine and Physiology, Taipei, Taiwan, November 3–6, 2012
This World Congress continues the tradition of the previous eight, which have brought together clinicians and scientists interested in high altitude from all over the world. Some of the highlights of these remarkable meetings are reviewed.
Sightings, edited by John W. Severinghaus (p. 143)
Clinician's Corner, edited by Andrew Luks
What do we know about safe ascent rates at high altitude?
Luks (p. 147) reviews existing recommendations about safe ascent rates and notes that there is a paucity of well-controlled studies. He also points out that the issue is most important for people who are going to high altitude for the first time.
SPECIAL TOPIC: THE MANY FACES OF HYPOXIA
HIF-1 at the blood-brain barrier: A mediator of permeability?
Ogunshola and Al Ahmad (p. 153) discuss how the blood-brain barrier plays a major role in many neurological diseases and they review recent work indicating that the barrier is affected by hypoxia in response to hypoxia inducible factors. Is this a clue to the pathogenesis of high altitude cerebral edema?
Hypoxia-mediated regulation of stem cell fate
Singh and co-workers (p. 162) address the role of hypoxia in mammalian development and consider its contribution to various pathological conditions. There is evidence that some stem cells exist in a very hypoxic micro-environment and that hypoxia inducible factors play an important part in their responses.
Hypoxia in the eye: A two-sided coin
Grimm (p. 169) points out that hypoxia is important in the normal development of the retina. However hypoxia also is a significant factor in retinal pathophysiology. Increased expression of VEGF by hypoxia inducible factors is believed to be important in several retinal pathologies including retinopathy of prematurity, diabetic retinopathy, glaucoma, and age-related macular degeneration.
The hypoxic placenta
Martha C. Tissot van Patot and colleagues (p. 176) discuss the role of hypoxia in the placenta and the related vascular remodeling, hypertension, metabolic changes, and mitochondrial dysfunction.
OTHER SCIENTIFIC PAPERS
Visual analogue self assessment of acute mountain sickness in adolescents: Experience from two Himalayan Expeditions
Slingo and others (p. 185) point out that there is increasing interest in visual analogue scales (VAS) as an alternative to the Lake Louise Self-Report Score for acute mountain sickness. They studied the use of visual analogue scales in two expeditions to Ladakh composed of 70 school leavers, mean age 17.4 years. Although there was a good correlation between the VAS and LLS scores, there was a tendency for the VAS to underscore symptoms of mild acute mountain sickness.
Optic nerve sheath diameter is not related to high-altitude headache: A randomized controlled trial
Lawley and collaborators (p. 193) note that the pathogenesis of high altitude headache is not known and they investigated whether there was a correlation with optic nerve sheath diameter (ONSD), which is believed to be related to intracranial pressure. The investigators also tested the effects of acetazolamide and a placebo. They found that acetazolamide had no significant effect on headache or ONSD. Furthermore ONSD increased similarly in subjects that had headache and those that did not. The conclusion was that intracranial pressure does not play a role in the development of mild high altitude headache.
Termination of cardiopulmonary resuscitation in mountain rescue
Powell and others (p. 200) report the recommendations of a group from ICAR MEDCOM on the difficult problem of when to terminate resuscitation attempts in mountain rescue patients. The investigation included a review of 96 abstracts of articles on this topic. These detailed recommendations should be valuable to people involved with mountain rescue.
Effect of the endothelin receptor antagonist bosentan on chronic hypoxia-induced inflammation and chemoafferent neuron adaptation in rat carotid body
Liu and colleagues (p. 209) studied the effects of chronic hypoxia on rat carotid body. This is known to be associated with an inflammatory response, immune cell invasion, and expression of pro-inflammatory cytokines. This study focused on the effect of Type A endothelin receptors on the development of inflammation. The conclusion was that endothelin-1 affects chemosensory type I cells and immune cells in the carotid body through Type A endothelin receptors.
BRIEF REPORT
Bosentan reduces pulmonary artery pressure in high altitude residents
Kojonazarov and colleagues (p. 217) investigated the importance of endothelin-1 (ET-1) in the pathogenesis of high altitude pulmonary arterial hypertension in permanent residents of the Kyrgyz Republic, altitude 3200–4000 m. They found that plasma ET-1 in highlanders with pulmonary hypertension was significantly higher than in healthy subjects, and after treatment with bosentan systolic pulmonary pressure decreased significantly. The conclusion was that increased ET-1 levels play a role in the development of high altitude pulmonary hypertension.
HISTORICAL ARTICLE
Arnold Durig (1872–1961): Life and work—An Austrian pioneer in exercise and high altitude physiology
Burtscher and associates (p. 224) discuss the work of this important figure in high altitude physiology who has not received the recognition that is his due. This is a welcome study of this influential scientist about whom there is a paucity of information.