Impotence, Sterility & Abortion

• FORENSIC CHARACTERIZATION OF BLOOD:

1) Is it blood? Use presumptive tests:

For VISIBLE STAINS:

                Kastle-Meyer: solution of phenolphthalein is applied to suspected blood stain, followed by hydrogen peroxide. A bright pink color indicates the presence of blood.

                Leuchomalachite Green: same procedure as K-M; produces blue-green color     in the presence of blood

For INVISIBLE STAINS:

                Luminol : alkaline solution containing luminol & hydrogen peroxide is sprayed onto area.  If blood is present, it will glow.Must be viewed in darkness and photographed quickly.

2) Is it human blood?

                Precipitin Test:

Precipitin test identifies the presence of proteins that are found only in human blood.

Precipitin Test Procedure

•          animal (usually a rat or rabbit) is injected with human blood

•          animal’s blood forms antibodies

•          antibodies are harvested from animal’s blood serum (“antiserum”)

•          in a test tube, an extract from the suspected bloodstain is added to the antiserum

•          if a precipitate forms where the two meet, it is human blood

3) Can it be associated with an individual? DNA

• A blood type (40-42%) is most common among Caucasians and those of European descent. 
• B blood type (10-12%) is most common among African Americans and Thai Asians.
• AB blood type (3-5%) is most common among Japanese & Chinese populations.
• O blood type (43-45%) is most common among indigenous peoples and Latin Americans.

• FORENSIC CHARACTERIZATION OF SEMEN

Presumptive Tests

1.       UV light (semen fluoresces under UV light)

[What else fluoresces? Fibers, coffee, food, detergent, most organic stains]

2.       Acid Phosphatase (reagent rapidly turns purple if AP is present)

3.       P30 (= PSA) test (enzyme found exclusively in seminal fluid)  

Early detection methods-electrophoretic double diffusion, Ouchterlony (precipitation band)

Confirmatory Test Required: Microscopic examination of sperm

Most common staining method is Kernechtrot picroindigocarmine stain- Also called Christmas Tree Stain

Seminal Fluid
• Seminal stains have to be detected in cases of rape or attempted rape, sexual murder of the female, sodomy and bestiality.
• Fertility of fluid has to be proved in disputed paternity.
• Seminal fluid choline is originated from Leyding cells.
• Smegma: If the smegma is present around glans of penis, it is suggestive of the fact that an individual did not have sexual intercourse in last 24 hours.

CHEMICAL EXAMINATION
a. Florence test: (Choline Per. Iodide cystols)

• The stain is extracted by 1% hydrochloric acid and a drop is placed on a glass slide.

• A drop of Florence solution (Postassium iodine, iodine and water) is allowed to run under the cover slip.

• If semen is present, dark-brown crystals of choline iodide appear immediately.

• They are rhombic crystals resembling haemin.

• A negative test means the fluid is not semen.

b. Barberio’s test:

• A saturated aqueous or alcoholic solution of picric acid* when added to spermatic fluid, produces yellow needle shaped rhombic crystals of spermine picrate.

• In Barberio’s test, presence of spermine in semen is detected.

• Spermine picrate crystals are seen.

c. The Acid phosphatase test:

• The prostatic secretion element of seminal fluid contains a very much higher percentage of acid phosphatase.

• This test is conclusive in the absence of demonstrable sperms or in aspermia.

d. Creatine phosphokinase: Level of CPK is high in seminol fluids, can be detected in old stains of 6 months.
e. Ammouium molybdate test:

• For semen stains, detect presence of phosphorous.

f. Glycoprotein P₃₀: This test has replaced the quantitative analysis for acid phosphatase.
g. MHS-S1 is also positive and a highly reliable test for semen.
h. Serological typing of the semen is possible by precipitin method.

• FORENSIC CHARACTERIZATION OF SALIVA

UV light can be used to aid in locating saliva stains

• The intensity of the fluorescence can be affected by the substrate, concentration of the stain, and other body fluids
• Saliva does not fluoresce as intensely as semen

A simple test for saliva involves mixing starch, iodine, and a sample of the presumed saliva together. Starch and iodine are a deep blue color when mixed together. The amylase breaks down starch, however, and the color fades (takes about 15 mins @ 37 ^oC).

• FORENSIC CHARACTERIZATION OF HAIR

Hair root material-suitable for nuclear DNA analysis (Characteristic of a particular growth phase)

If not suitable for nuclear DNA analysis, determine if the hair is sufficient in size for mtDNA analysis (2-3cm)