dr. shiuli, forensic medicine & toxicology, kgmu
TRANSCRIPT
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Different stains having Medicolegal importance
Blood Seminal fluid Vaginal discharge Saliva Faecal stain Urine
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Blood stains
-Main cellular content RBC – Haemoglobin which possess peroxidase activity-Haemoglobin and other proteins of blood has antigenic properties – produces antibodies when injected into animals
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Medicolegal importance May establish a link between offence,
offended and offender May establish link between offence and
offensive agent Fictitious charges by presenting an
animal stain as human In poisoning, poison chemically
detected Time since death may be estimated by
chemical and enzymatic study
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Examination
Whether the stain is actually a blood stain
• Physical• Chemical• Microscopic• Spectroscopic • Micro chemical
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Whether the blood stain is of human or other than human
• Precipitin test If human, which blood group Sex, source Indication as to cause of death Whether belong to victim or accused Whether bleeding antemortem or
postmortem Any disease process
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Substances resembling blood stain
Vegetable stains- ammonia greenish yellow color- Bleached by chlorine water- M/E vegetable cells and fibers Rust stains- Does not fall off in scale on being
heated- Positive reaction for iron- Dissolved in dil. Hcl
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Mineral stains Synthetic dye stains- Nitric acid yellow strong alkali original color Other stains
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Chemical examination Highly sensitive Positive reaction even with faint traces
of blood Principal factor – peroxidase activity
liberating nascent oxygen which leads to colour change
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
1. BENZIDINE TEST
stain extract ┼ benzidine ┼ 10 vol
in hydogen peroxide
glacial acetic acid
Blue colour
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
2. KASTLE MAYER TEST- Phenolphthalein in alkaline medium- Pink colour
3. ORTHOTOLIDINE TEST- (4% orthotolidine in ethyl alcohol)+
glacial acetic acid + H2O2 - Green colour
4. LEUCHOMALACHITE GREEN TEST- Bluish green colour5. LUMINAL TEST
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Microscopic test
RBC’s- confirmatory Species Sex Disease
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Microchemical test
HAEMIN CRYSTAL TEST/ TEICHMAN’S TEST
- Sod. Chloride + strain extract + glacial acetic acid
- Yellowish brown rhombic crystals of haemin
HAEMOCHROMOGEN CRYSTAL/ TAKAYAMA TEST
- takayama reagent + stain extract- Salmon pink hemochromogen crystals
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Spectroscopic examination
Detects blood where RBC structure is lost and hemoglobin has undergone chemical composition
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Species specification test
PRECIPITIN TEST- When human serum is injected in an
experimental animal, antibodies develop.
- When any human serum is brought in contact with this animal serum, the antibodies and protein will react and a visible precipitate will develop
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Identifying sex from blood stain- Barr bodies in > 3% of polymorphs- Y chromosome is fluorescent to quinacrine
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Individuality by blood stain
Blood grouping• red cell antigen•White cell antigen•Se protein polymorphism•Red cell enzyme polymorphism
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Red cell antigen ABO system Rh system MNSs group system Lutheran Duffy Lewis Kidd
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Gro
up
sp
ecifi
c
su
bsta
nces
secre
tors
Non
secre
tors
Agglutinogens in water soluble form Secrete ABO antigens into body fluids
and secretions
Agglutinogens in lipoidal form
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
White cell antigen
Human Leucocyte Antigen (HLA)- the MHC in humans
Present on Chromosome 6 and encode cell surface antigen presenting proteins
4 types – HLA-A, HLA-B, HLA-C, HLA-D
Dr. Shiuli, Forensic Medicine & Toxicology, KGMU
Serum protein polymorphism
Occurrence in the same population of two or more alleles at one locus, each with appreciable frequency, where the minimum frequency is taken as 1%
Se. proteins subject to genetic variation are
• Se. haptoglobins• Se lipoproteins• Abnormal haemoglobins