Table 1.

Mitochondrial injury scoring system based upon the stages of cellular injury^*

Cellular injury stage†	Mitochondrial injury score†	Mitochondrial characteristics
Stage I	0.0	Normal appearance
Stage II/III	1.0	Swelling of endoplasmic reticulum, minimal mitochondrial swelling
Stage IV‡	2.0	Mild mitochondrial swelling
	3.0‡	Moderate or focal high-amplitude swelling
	4.0	Diffuse high-amplitude swelling
Stage V/VI	5.0	High-amplitude swelling with mitochondrial flocculent densities and/or calcifications

^*Electron microscopy was used to visualize the extent of mitochondrial ultrastructural injury in the lungs and ileum, which was then quantitatively assessed (Scale of 0–5) based upon the cellular injury staging system described by Trump et al. (1980).

^†Stages and Scores do not directly correlate because indices of cellular injury other than mitochondrial changes were not taken into consideration during determinations of mitochondrial injury.

^‡Irreversible cell damage is noted to occur during this stage, and mitochondrial injury scores >3.0 are predictive of ultimate cell death (Trump et al. 1980).