Effect of Acute Hypoxia Exposure on the Availability of A Adenosine Receptors and Perfusion in the Human Brain.

In animal studies it has been observed that the inhibitory neuromodulator adenosine is released into the cerebral interstitial space during hypoxic challenges. Adenosine's actions on the A adenosine receptor (AAR) protect the brain from oxygen deprivation and overexertion through adjustments in cerebral blood flow, metabolism, and electric activity. Using 8-cyclopentyl-3-(3-[F]fluoropropyl)-1-propylxanthine ([F]CPFPX), a PET tracer for the AAR, we tested the hypothesis that hypoxia-induced adenosine release reduces AAR availability in the human brain.

Simulating microgravity with 60 days of 6 degree head-down tilt bed rest compromises sleep.

Astronauts in space often experience sleep loss. In the AGBRESA (Artificial Gravity Bed Rest) study, we examined 24 participants (mean age ± SD, 33 ± 9 years) during two months of 6 head-down tilt (HDT) bed rest, which is a well-established spaceflight analogue. Polysomnography was recorded during baseline (BDC-9), HDT (nights 1, 8, 30 and 58) and recovery (R, nights 1 and 12).

Chest compression quality decreases in hypoxic conditions simulating an airliner cabin at cruising altitude: a randomized, controlled, double-blind Manikin Study.

Air traveler numbers are predicted to reach 4.0 billion in 2024. Between 1/15,000-50,000 passengers will experience acute medical problems inflight with cardiac arrests requiring cardiopulmonary resuscitation (CPR) accounting for 0.

Repeated caffeine intake suppresses cerebral grey matter responses to chronic sleep restriction in an A adenosine receptor-dependent manner: a double-blind randomized controlled study with PET-MRI.

Evidence has shown that both sleep loss and daily caffeine intake can induce changes in grey matter (GM). Caffeine is frequently used to combat sleepiness and impaired performance caused by insufficient sleep. It is unclear (1) whether daily use of caffeine could prevent or exacerbate the GM alterations induced by 5-day sleep restriction (i.