Upon completion of the test, participants rested in a seated position for 3 min in the environmental condition for that testing day, before exiting the environmental chamber and remaining under normoxic conditions thereafter.
Cells placed under normoxic conditions were maintained according to the parameters as described in preceding paragraphs, whereas, for subjecting to hypoxia stress, the HEK 293 cells were retained in a low oxygen environment (1% [O.sub.2], 5% C[O.sub.2], and 94.5% [N.sub.2]) for 24 h in a Galaxy 48R incubator (New Brunswick).
As shown in Figures 1(a) and 1(b), H9C2 cells exposed to HG stimulation exhibited decreased cell viability and increased LDH release as compared with LG group in normoxic conditions, and these alterations were further increased by H/R insult as compared with those in the corresponding normoxic groups, indicating that HG-treated H9C2 cells are more vulnerable to H/R injury.
Groups of male and female Wt and STAT5-/- mice were exposed to hypoxia (10% hypobaric oxygen) for 4 weeks or kept under normoxic conditions, and the development of PAH was first evaluated as previously reported (RVSP, ratio of RV/LV + S weights, increased muscularization of vessels, and increased arterial wall thickness) .
Recent data from a study using pharmacological blockade of the sympathetic and parasympathetic nervous system  suggest that even though sympathetic nervous system activity increases as compared to normoxic state, parasympathetic withdrawal rather than sympathetic activation seems to be the cause of the increase in heart rate observed in healthy humans subjected to hyperbaric hypoxia.