Red blood cell endothelial cells. Exposure of red blood cells to physiological levels of shear stress activates nitric oxide synthase and export of nitric oxide, which may contribute to the regulation of vascular tonus. Red blood cells can also produce hydrogen sulfide, a signalling gas that acts to relax vessel walls. It is believed that the cardioprotective effects of garlic are due to red blood cells converting its sulfur compounds into hydrogen sulfide. Red blood cells also play a part in the body's immune response: when lysed by pathogens such as bacteria, their hemoglobin releases free radicals, which break down the pathogen's cell
Under a Blood Red Sky Under a Blood Red Sky Under a Blood Red Sky is a live album by Irish rock band U2, produced by Jimmy Iovine and released on 21 November 1983. Along with its companion concert film, "", the release helped establish U2's reputation globally as a live act. The album consists of live recordings from three shows on the band's War Tour, from Colorado and Boston in the US and from Germany. An accompanying concert video entitled "U2 Live at Red Rocks: Under a Blood Red Sky" was released the following year. The film was recorded entirely at the outdoor Red