uOutside of allergy
and addiction research,
few human or animal
studies are designed to assess their
subjects’ their
degree of sensitization or habituation
uHuman exposure
studies considered by those establishing Occupational Exposure Limits (TLVs) do not usually include retired and thus potentially sensitized workers, but instead focus on tolerances of those still working, who are most likely
to have the highest
tolerances.
uMost animal exposure
use identically raised animals with no prior exposure experience which are then exposed to high levels according to a frequent dosing schedule. This is an excellent design to induce habituation, but animal studies
are rarely designed
to also assess sensitization by keeping a cohort alive longer through a long withdrawal period
followed by re-exposure at
a much lower level.