Toxicology of Industrial Compounds

cells, including eosinophils, in the bronchoalveolar lavage fluid (BALF)
were consistent with an asthma like syndrome. As evident from Figure 9.2,
the changes observed in rats exposed to 7 mg m −3 air did not fully regress
during an observation period of approximately 2 months.
Conclusion
J.PAULUHN 135
Figure 9.2 Relative comparison of sensitive diagnostic parameters in rats exposed to
either 0 (air), 1, 4 and 7 mg PI m −3 air for 2 consecutive weeks (6 h day −1 , 5 days
week −1 ). The measurements were performed in weeks 3 and 9. Abbreviations:
MMEF: Maximal mid-expiratory flow rate, Q s/Q t: venous admixture, PMN:
polymorphonuclear cells, Eos: eosinophilic granulocytes, Sialomucins: total sialic
acid (after hydrolysis).
Experimental evidence suggests that changes within the respiratory tract
leading to the reactive airway dysfunction syndrome and/or asthma are
fully consistent with an inflammatory response involving tissue of direct
contact. The toxicity of irritant chemicals known to induce such illness is
highly focal, and the variability of response in different regions of the
respiratory tract could be a result of the actual concentration of the
toxicant reaching various airway levels. Determination of immunologic
etiology is particularly important for chemical allergy since all recognized
low-molecular-weight chemical sensitizers are also respiratory irritants and
in sufficient concentrations can cause airway constriction by
nonimmunological mechanisms. As shown by studies using phenyl