Theme 6 Tissue biomarkers.

: Glutamate excitotoxicity is a longstanding hypothesis in the pathophysiology of ALS. Prior studies have demonstrated increased plasma glutamate levels in ALS patients, which suggest a systemic defect in glutamate metabolism (1). The most abundant amino acid consumed in our diet is glutamate.

Ultrastructural changes produced in dorsal root ganglia in vitro by exposure to ethylene oxide from hemodialyzers.

Ethylene oxide (EO) gas, used to sterilize hemodialysis equipment, is a known neurotoxin and residual gas remains in dialyzers after airing. If tissue culture medium is incubated in dialyzers and then rat dorsal root ganglion (DRG) cultures are exposed to this medium, characteristic changes occur. These include axonal swellings and the death of neurons after five days.