Editorial: Oxygen Sensing (p. 67)

The discovery of Hypoxia Inducible Factors is transforming our discipline of high altitude medicine and biology. It is now clear that these transcription factors operate as a master switch in response to hypoxia that upregulate or downregulate hundreds of genes that have multiple effects on human physiology.

Sightings, Edited by John W. Severinghaus (p. 70)

Clinician's Corner, Edited by Andrew Luks

Travel to high altitude during pregnancy

Jean and Moore (p. 73) discuss the problems for the mother, fetus and prospective child when lowlanders travel to high altitude. They offer the best available advice to date but acknowledge that there is a paucity of evidence on which to base this.

SCIENTIFIC PAPERS

Reappraisal of acetazolamide for the prevention of acute mountain sickness: A systematic review and meta-analysis

Kayser and colleagues (p. 82) provide an in-depth review of the many publications in this area using meta-analysis. They conclude that acetazolamide is useful in the prevention of AMS but that its value is limited when the risk is low. There is some evidence that the efficacy increases with dose.

Evaluation of the balance error scoring system (BESS) test in the diagnosis of acute mountain sickness at 4380 m

MacInnis and co-workers (p. 93) report on the value of human balance measurements in the diagnosis of Acute Mountain Sickness. The study was carried out on 37 subjects at an altitude of 4380 m. Subjects who reported AMS had a higher degree of impaired balance but additional studies are needed to determine if this test is a useful adjunct to the traditional Lake Louise score.

An ecological study of cancer mortality rates in high altitude counties of the United States

Youk and colleagues (p. 98) tested the hypothesis that residents of high altitude have a higher cancer death rate than people who live at low altitudes. This has been suggested because of a possible link between polycythemia and cancer deaths. Various types of cancers were studied. The statistical analysis concluded that there is no evidence that persons residing at high altitude are at an elevated risk of cancer mortality.

The effects of acute hypobaric hypoxia on arterial stiffness and endothelial function and its relationship to changes in pulmonary artery pressure and left ventricular diastolic function

Boos and co-workers (p. 105) studied the effects of 3 hours of simulated high altitude on aspects of the systemic circulation, particularly the stiffness of large arteries. The stiffness depends on the balance between local endothelial derived vasodilation and sympathetically mediated vasoconstriction. They found that acute hypobaric hypoxia did not affect large artery stiffness but noted that the hypoxia reduced systemic vascular resistance but increased pulmonary vascular responses.

Pediatric trauma in Austrian Alps – the epidemiology of sport-related injuries in Helicopter Emergency Medical Service

Selig and associates (p. 112) report on sport-related traumatic injuries of children in the European Alps. Skiing was the most dangerous sport and it mainly affected late school-age boys. The most frequent injuries were to the head, face and spine. The value of helmets and the avoidance of risky behavior are emphasized.

Compromised white matter microstructural integrity after mountain climbing: evidence from diffusion tensor imaging

Zhang and colleagues (p. 118) carried out a sophisticated analysis of MRI images of the brain before and after an ascent to 6206 m. Cognitive tests showed no changes but it was found that short term high altitude exposure caused some changes in the MRI appearances of white matter.

Distribution of sexual and asexual Ostracoda (Crustacea) from different altitudinal ranges in Ordu region, Turkey: testing Rapoport Rule

Külköylüoğlu and colleagues (p. 126) tested the hypothesis that increasing altitude decreases species richness, that is the amount of species variation. The measurements were made on freshwater crustaceans in an area of Turkey. The finding was that in fact there was increased species diversity at high altitude probably as a result of the greater variation of the habitat. This ecological study is an unusual publication for our Journal but reminds us that high altitude biology covers a very diverse area.

LETTER TO THE EDITOR:

Suicide at high altitude: the importance of sociodemographic and mental health care factor

Betz and co-workers (p. 138) clarified a misunderstanding about an earlier paper in this Journal about suicide and high altitude. In a comment on the paper, a letter to the editor stated that there was a higher incidence of depression with increasing altitude. However this was not accurate. The article simply reported that more people who committed suicide at high altitude appeared to be depressed at the time of their death compared with suicide victims at sea level.