Full details Toxicological Evidence.pdf

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1. Toxicological Evidence
By: Abdur Rehman
PhD Scholar
Biochemistry
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2. Toxicological Evidence
•A
Poison in modern era:
–P
–Combination of drugs and its side effect complicate
poisoning detection
–Poison detection need collaborative approach among
practitioner, pathologist, MLO, forensic scientist
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3. Approach towards toxicological evidence
1.T
•Medicine in toxic dose; Poison & Poison in small dose;
medicine
•For Example ; Chloral Hydrate 300 mg is hypnotic & 3gm
act knock out drop (poison) use for robbery, rape cases
•Barbiturates small dose treat insomnia, but coma & death
in normal person
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4. •P
–S
–Autopsy findings
–Evidence of pathological lesions
–Conclusive evidence; absorption of toxic substance n tissue
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5. 2.T
•D
in low concentration
•The proof to find, absorbed toxic substance in tissue of
visceral organ/blood/urine
•If specific substance suspected, direct analysis can be
made
•As rule general systematic toxicological examination
preferred even if particular poison suspected
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6. •P
–Setc)
–History of case
–Autopsy findings
–Gross/Microscopic findings
•A
forensic examination helpful
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7. •P it complicates
toxicological analysis, problem in interpretation of results
–Ce.g
parathion, aconite
–Putrefaction produce toxic substance from normal tissue, interfere
in result
–Volatile substance lost due to putrefaction
–Ethyalcohalmay produced from normal tissue in advance
putrefaction
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8. 3.T
•A
required in some cases
•Interpretation of quantitative data, i.efatal dose of
poison
•Record of poison & knowledge of toxicokineticsis
important
•During reporting extreme care should be taken
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9. Toxicological evidence interpretation cont..
1)N general scheme of
study give negative result e.ginsulin
2)History Of Poisoning, No positive findings: it could
happened if
a)The poison vomited out, detoxified or small quantity
–e succinyl choline injectedas homicide, metabolized in body to
succinate & choline; which are normal constituent of body tissue
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10. Toxicological evidence interpretation cont..
b)L
ingestion & death
c)The absorbed poison not evenly distributed;
organ/tissues
d)Rout of administration varies concentration e.gorally vs
IV varies conc in blood & liver
e)Too little specimen; hard to detect
f)Highly potent toxic substance (low LD)
g)Victim treated may alter poison nature
Note: don’t interpret report as “No Poison detected”
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11. Toxicological evidence interpretation cont..
3)Alt isolated
material may not identical due to alteration by
biochemical process such as
–Fin phenobarbitonewhen primidonehas been taken
–Finding oxazepamwhen diazepam has been taken
–Finding Morphine if heroin is involved
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12. Toxicological evidence interpretation cont..
4)L a substance
may varies from slight effect to over dosage, lethal
dose cant be fixed
–Hae.g age, sex, weight
5)D in quantitative
measurement the reasonable range of probable error would be around 2 +SD-.
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13. Toxicological evidence interpretation cont..
6)N vsObserved Concentration of
Poison: toxic substance may or may not present
normally in body
–If pr
pollution its magnitude may be determined
–E.gaverage arsenic content of 1/2ppm but up to 4ppm may
be considered normal, chronic long term arsenic poisoning
may result in 70 ppm of arsenic in hairs & nails
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14. Reference
•TSubrahmanym Seventh edition
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