Transport and reaction at endothelial plasmalemma: Distinguishing intra- from extracellular events

The pulmonary endothelium is a chemical reactor that modifies blood composi tion in several ways, including reduction of the oxidized forms of certain redox active substances in the blood. The physiological functions of the tr ansplasma membrane electron transport systems involved in the latter an not fully understood, but an argument is made that they are involved in antiox idant defense. In addition, the experimental approaches used to characteriz e the process, including studies at whole organ, cell culture, and subcellu lar levels, along with the use of mathematical modeling, may be representat ive of the physiome concept wherein a goal is the integration of informatio n obtained at all levels of biological organization. In this article, separ ation of intra- and extracellular events involved in the disposition of red ox active probes within the lungs is the particular example. (C) 2000 Biome dical Engineering Society. [S0090-6964(00)00508-7].