metals

Question 1

• In general metals exert their toxicity by:

Answer 1

• Ionic forms can react with cell components and inhibit critical enzymes
• Mimicry – acting as a mimic of essential metals
• Metal mediated oxidative damage catalysis of redox reactions causing DNA and protein damage

Question 2

Biomarkers for metal concentration in:

Answer 2

• Blood
• Urine
• Hair
• DNA-protein complex for Chromium

Question 3

Elevated levels of metals

Answer 3

Intracellular damage:
* Oxidative stress: lipid peroxidation –DNA damage –organelle dysfunction
* Binding to proteins
* Displacing metals from metalloproteins

Question 4

activate certain genes that help protect against damage by:

Answer 4

• Remove metal from cell via chelation or increased export
• Reduce the level of oxidative stress
• Repair metal induced intracellular damage

Question 5

Ceruloplasmin: Metal Binding Proteins

Answer 5

Cu containing glycoprotein oxidase in plasma – converts Fe to Fe+3 which binds to transferrin

Question 6

lead properties

Answer 6

softness, malleability, resistance to
corrosion.

non-biodegradable

Question 7

II. Hematological Effects of lead

Answer 7

Lead inhibits:
* δ-aminolevulinic acid dehydratase (ALAD) preventing
porphobilinogen formation with ALA accumulation
* Ferrochelatase preventing incorporation of iron into
protoporphyrin IX with protoporphyrin accumulation

This prevents heme synthesis with microcytic anemia

Question 8

IV. Cardiovascular Effects of lead

Answer 8

1. Inactivation of NO through lead induced ROS
2. Changes in the RAA system, increased sympathetic activity
3. Alteration in Ca+2 dependent functions of vascular smooth muscle contractility
4. Rise in endothelin and thromboxane

Question 9

Lead Poisoning – Prevention

Answer 9

Best approach – avoid exposure
* Frequent hand washing
* Increase intake of Ca and Fe
* Discourage children from putting hands in their mouth
* Frequent vacuuming
* Replacing lead pipes if present