The present study examined the acute effects of hypoxia on the regulation of skeletal muscle metabolism at rest and during 15 min of submaximal exercise. Subjects exercised on two occasions for 15 min at 55% of their normoxic maximal oxygen uptake while breathing 11% O(2) (hypoxia) or room air (normoxia). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects...

At birth, release of endogenous vasodilators such as nitric oxide and prostacyclin facilitate pulmonary vasodilation via the cyclic nucleotides, cGMP and cAMP. Interaction of cyclic nucleotides and platelet-activating factor (PAF)-mediated responses in pulmonary vascular smooth muscle is not known. We studied the effects of cGMP and cAMP on PAF-mediated responses in ovine fetal intrapulmonary v...

Al~tmct. The extracellular acid-base status of the freshwater rainbow trout (Salmo gairdneri) was continuously monitored during 24 h normoxia (Pxo: = 120-150 tort; control), 72 h hyperoxia (Pioz = 500-600 tort) and 24 h return to normoxia. Hyperoxla induced a marked respiratory acidosis (ApHe = -0.23 unit) due to a 3-fold elevation in arterial CO 2 tension which was completely compensated over ...

To improve our understanding of the limiting factors during repeated sprinting, we manipulated hypoxia severity during an initial set and examined the effects on performance and associated neuro-mechanical alterations during a subsequent set performed in normoxia. On separate days, 13 active males performed eight 5-s sprints (recovery = 25 s) on an instrumented treadmill in either normoxia near...

Systemic hypoxia, produced by lowering inspired Po2, induces a rapid inflammation in several microcirculations, including cremaster muscle. Mast cell activation is a necessary element of this response. Selective reduction of cremaster microvascular Po2 (PmO2) with normal systemic arterial Po2 (PaO2; cremaster hypoxia/systemic normoxia), however, does not elicit increased leukocyte-endothelial a...

To determine the impact of acute hypoxia on prohepcidin concentrations in humans, we measured concentrations of this peptide in serum collected during and after a transient period (30 min) of hypoxia and during normoxia. Prohepcidin concentrations were significantly lower 150 min after the end of hypoxia than after normoxia (p=0.028).

PURPOSE Endurance exercise and hypoxia regulate pathways that are crucial to glucose and lipid metabolism. We hypothesized that training under hypoxia results in similar or even greater metabolic improvement compared with exercise under normoxia at a lower workload. METHODS We randomly assigned 20 healthy men to single blind training under hypoxia (FiO2 = 15%) or normoxia (FiO2 = 21%). Subjec...

BACKGROUND Meniscal cartilage displays a poor repair capacity, especially when injury is located in the avascular region of the tissue. Cell-based tissue engineering strategies to generate functional meniscus substitutes is a promising approach to treat meniscus injuries. Meniscus fibrochondrocytes (MFC) can be used in this approach. However, MFC are unable to retain their phenotype when expand...

22 Exercise efficiency is an important determinant of exercise capacity. However, little is known 23 about the physiological factors that can modulate muscle efficiency during exercise. 24 Accordingly, we examined whether improved O2 availability would 1) impair mitochondrial 25 efficiency and shift the energy production toward aerobic ATP synthesis, 2) reduce the ATP cost 26 of dynamic contrac...

The mammalian target of rapamycin (mTOR) correlates with cell survival under hypoxia and regulates hypoxia-inducible factor-1α (HIF-1α), a key protein in hypoxia-related events. However, the role of mTOR in radio-resistance has not been fully investigated. Therefore, the effect of mTOR on the radio-resistance of cancer cells under hypoxia was evaluated using the mTOR inhibitor temsirolimus. Clo...