**13. Conclusions**

A novel *in vitro* system that allows monitoring of cellular respiration over several hours is described. The method has numerous biological applications, including studying mitochondrial dysfunction during apoptosis or toxic exposure. It also allows screening for metabolic disorders in patients. The procedure is sensitive and reproducible. It is applicable to cells in suspension, adherent cells and various organs, including the heart muscle, liver, spleen, pancreas and kidney.
