Various concentrations of oxygen were used to determine the optimum culture medium PO2 for survival and proliferation of attached human and mouse fibroblasts grown from different inoculum sizes. When T-15 flasks were seeded with less than or equal to 2 X 10(4) cells (less than or equal to 1.3 X 10(3) cells/cm2), the highest plating efficiencies and cell yields were obtained with a culture medium PO2 of 40-60 mm Hg.
American Journal of Physiology. Heart and Circulatory Physiology
We hypothesized that elevated partial pressures of O(2) would increase perivascular nitric oxide (*NO) synthesis. Rodents with O(2)- and.NO-specific microelectrodes implanted adjacent to the abdominal aorta were exposed to O(2) at partial pressures from 0.2 to 2.8 atmospheres absolute (ATA). Exposures to 2.0 and 2.8 ATA O(2) stimulated neuronal (type I) NO synthase (nNOS) and significantly increased steady-state.NO concentration, but the mechanism for enzyme activation differed at each partial pressure.
The oxygen status of skin is a controversial topic. Skin is radiosensitive, suggesting it is well-oxygenated. However, it can be further sensitized with nitroimidazole drugs, implying that it is partially hypoxic. Skin oxygen levels are difficult to measure with either electrodes or the hypoxia-monitoring agent (3)H-misonidazole. For the latter, binding has previously been reported to be high in murine skin, but this could be attributed to either non-oxygen-dependent variations in nitroreductase activity, drug metabolism, and/or actual oxygen gradients.
Using an ABA' design, the authors investigated the effects of Qi-training on blood gas concentrations with a 20 min control rest period (A), 1 h of Qi-training (B), and a 20-min rest period (A'). The blood partial pressures of oxygen (PO2) and carbon dioxide (PCO2), and oxygen content, oxygen saturation, and pH were significantly altered. The mean PO2 value increased significantly during Qi-training by 14 mmHg (about 24%, p < .01) compared with control A. During Qi-training, the mean decrease in PCO2 was 3 mmHg (about 10%).