Module 3: Toxicology - Section 4: Biological Monitoring

TOX 4.4: Lecture: Biological Monitoring and Biological Effect Monitoring - (Continued)

EXAMPLE OF BIOLOGICAL MONITORING - INORGANIC LEAD:

1. Legislated schedule including medical removal. (See OHSA- Regulations: Lead Regulations, 2001.)
2. Four compartment kinetics: blood, soft tissues, trabecular bone, cortical bone.
3. Interpretation of a given blood lead is different in new as vs long service workers.
4. Interlaboratory differences may be substantial (See the graph).

EXAMPLE OF BIOLOGICAL EFFECT MONITORING:

• Red cell cholinesterase
• Plasma cholinesterase

1. Use individual baseline as reference!
2. Normal variation, i.e. in absence of exposure: 10-15%.
3. 2-3 month recovery, i.e. return to baseline in absence of exposure.

BIOLOGICAL EFFECT MONITORING OF EXPOSURE TO POSSIBLE CARCINOGENS:

These tests are not used routinely but rather in toxicologic or epidemiologic research.

1. Urinary mutagens (Ames test)
   
   • non-specific test of genotoxicity;
   • smoking a confounder
     .
2. Haemoglobin and DNA-adducts e.g. benzo(a)pyrene
   (Adduct = chemical bond)
   • Specific but expensive. Doesn’t necessarily mean disease.
   
   
3. Chromosomal abnormalities ("clastogenic"),
   e.g. for ethylene oxide
   
   • chromosomal aberrations;
   • sister chromatid exchanges.
   • Oncogene activation.