Toxicity of lead:- Sources of expouser Signs and symptoms mechanism of poisoning & Some drugs for detoxification

1. TOXICITY OF
LEAD
AND IT’S
DETOXIFICATIN
Elaborated by: Shruti Soni

2. What is Lead?
• Lead is a heavy metal that is present at low levels in the
earth’s crust but has become pervasive in the
environment because of its use in products such as
gasoline, paint,
jewelry, water pipes, lead solder, and lead acid batteries.
• While it has some beneficial uses, it can be toxic to
humans and animals, causing health effects.
• The International Programme on Chemical Safety of the
World Health Organization (WHO) has identified lead as
one of the 10 chemicals of major public health concern.

3. Sources of Lead
Exposure
• Work environment
• Soil
• Ceramics
• Antique toys
• Artist oil paint
• Lead solder
• Drinking water
• Fishing tackle
• Costume/toy jewelry

4. So the route of exposure is :
1- inhalation (most rapid)
2- ingestion (absorption is facilitated by young age and
diet deficient in calcium, iron, and /or zinc) .
3-Transdermal (least efficient , but organic absorption
<inorganic absorption).

5. Signs and symptoms :
Severe (whole blood lead level (BLL)
>100-150 mg/dl)
• encephalopathy (i.e., coma , seizures, signs of
increase Intracarnial pressure)
• foot/wrist drop
• abdominal pain
• Vomiting
• anemia

7. Moderate
(BLL >80 mg /dl )
• Headache
• memory loss
• Fatigue
• Irritability
• Insomnia
• muscle pain/weakness
• abdominal pain
• weight loss
• nephropathy
Mild (BLL > 40
mg/dl )
•Fatigue
•Moodiness
•Hypertention
•decereas in interest in
everyday activities .

9. Mechanisms of Toxicity
Lead exerts numerous adverse mechanisms of toxicity.
1-Lead has a high affinity for sulfhydryl groups which
interfere with enzymes and structural proteins .
2-Many of lead’s toxic effects also result from its
inhibition of cellular function requiring calcium(lead is
chemically resembles calcium).
Lead binds to calcium-activated proteins with
much higher (105 times) affinity than calcium.

10. So interfere with calcium homeostasis and calcium-
dependent signaling and metabolic Pathways.
3-It interferes with the biosynthesis of porphyrin
required
in Hb synthesis. It’s poisoning produces anemia.
4-Lead metal causes toxicity in living cells by ionic
mechanism and that of oxidative stress. Oxidative stress
in living cells is caused by the imbalance between the
production of free radicals and the generation of
antioxidants.

11. • Antioxidants, as e.g. glutathione, present in the cell protect
it from free radicals such as H2
O2.
Under the influence of
lead, however, the level of the ROS increases and the level
of antioxidants decreases.
•Since glutathione exists both in reduced (GSH) and
oxidized (GSSG) state, the reduced form of glutathione
gives its reducing equivalents (H+
+ e−
) from its thiol groups
of cystein to ROS in order to make them stable. In the
presence of the enzyme glutathione peroxidase, reduced
glutathione readily binds with another molecule of
glutathione after donating the electron and forms
glutathione disulfide (GSSG).

13. GSH
GSSG

14. Organolead poisoning
• Today very rare.
• Organolead compounds like lead stearate and lead
naphthenate are still used in some commercial processes.
• Organolead compounds are well absorbed through the
respiratory tract and skin. These compounds target the
central nervous system and produce dose-dependent
effects:
฀ neurocognitive deficits
฀ insomnia, delirium, hallucinations
฀ tremor, convulsions
฀ death.

15. Treatment
•Intravenous edetate calcium disodium (CaNa2
EDTA).
•Some clinicians use dimercaprol intramuscular
injection in case of lead encephalopathy.
•Succimer : Dimercaptosuccinic acid, is a medication
used to treat lead, mercury, and arsenic poisoning.
•Endoscopic removal is indicated if the lead is in
the stomach or esophagus.
atmnt
Intravenous etate calcium
disodium (CaNa2EDTA)

16. REFERENCE
✔https://www.ncbi.nlm.nih.gov/pmc/articles/PMC
4427717/

17. Thank You