Topic 3 Flashcards
Examination of semen and seminal stains is an important part in the routine investigation of sexual offense like cases of rape, adultery, sodomy, bestiality and sexual homicide.
SEMEN AND SEMINAL STAIN
– this refers to a whitish fluid of the male reproductive tract consisting of spermatozoa suspended in secretion of accessory glands.
Semen
Has characteristic alkaline color odor, it is viscid, gelatinous and sticky. It becomes more liquid in character when exposed to air for one and half – hour due probably to enzymatic reaction that is slightly alkaline in reaction.
Seminal Fluid
– this refers to small object with a pear – shaped head behind is a short neck and then a tail of about ten times as long as the head.
Spermatozoa or Sperm Cell
- arecells that come from surfaces of your body, such as your skin, blood vessels, urinary tract, or organs. They serve as a barrier between the inside and outside of your body, and protect it from viruses. A small number of epithelial cells in your urine is normal.
Epithelial Cells
– one point five (1.5)ml to 3.5ml is the normal quantity of seminal fluid in a single ejaculation, 400 to 500 million is the total number of spermatozoa contained in a single ejaculate from a healthy young man.
Crystal of Choline and Lecithin
, also calledPhosphatidyl Choline, any of a group of phospholipids (phosphoglycerides) that are important in cell structure andmetabolism.
Lecithin
are composed ofphosphoric acid, cholines, esters ofglycerol, and two fatty acids; the chain length, position, and degree of unsaturation of these fatty acids vary, and this variation results in different lecithins with different biological functions.
Lecithins
is white and waxy and darkens when exposed to air.
Pure lecithin
is brown to light yellow, and its consistency varies fromplastictoliquid.
Commercial lecithin
– this refers to the complete absence of spermatozoa from the ejaculate. This diagnosis must be confirmed by centrifugation of a semen specimen for 15 min at room temperature with high-powered microscopic examination of the pellet and a centrifugation speed of at least 3,000g.
Azoospermia
– refers to an abnormally low concentration of sperms in the seminal fluid. Fertile semen contains about 100,000,000 sperms per ml. semen with less than about 20,000,000 sperms per ml are likely to be infertile.
Oligospermia
– this refers to a condition in which there are dead or immobile spermatozoa in the semen.
Necrospermia
– this is known after the name of Dr. Florence of Lysons, who first introduce it.
Florence Test
test isused to detect the presence of choline, a quaternary saturated amine with the chemical formula (CH3)3N+CH2CH2OH. Choline is an essential nutrient and is found in many foodstuffs, but is particularly concentrated in meat and dairy produce.
Florence Iodine
Visible/Positive Results: Crystals of Choline Periodide, which are dark brown, rhombic or needle shaped that occur singly or in cross or even grouped in cluster. It resembles haemin crystal in shape, size and color.
Florence Test
: A saturated aqueous or alcoholic solution of picric acid when added to dried stain extract on a glass slide covered with a coverslip, produces yellow needle-shaped crystals of spermine picrate.
Barberio’s test
Positive Results: Crystal that are slender yellow tinted, rhomboid needles with obtuse angle or appear as ovoid crystals. These crystals are made of specimen pictrate.
Barberio’s test
is almost specific for human semen. The seminal stain as old as six years are said to respond to the test. This test is carried out with fresh, dried or dissolved semen.
Barberio’s Test
– this test is the best way to locate and at the same time characterize a seminal stain. It has replace the Florence test in reliability and was shown to be specific for human and higher apes. The test is based fundamentally upon the extraordinary high acid phosphatase content of human male ejaculation. Phosphatase is the enzymes present in semen.
Acid Phosphatase Test
Positive Results: Purple color. Purple color is indicative of Acid Phosphatase
Acid Phosphatase Test
– the chief purpose of microscopic examination is to determine the presence of spermatozoa.
Microscopic Examination of Semen and Seminal Stains
– the spermato – precipitins are of value in the identification of seminal fluid in certain case like for examples, beastiality when it may be desirable to differentiate between the human seminal fluid from that of an animal.
Biological Examination of Semen and Seminal Stain
– this refers to examination at the scene of the crime in cases of criminal abortion, infanticide and sex offenses may lead to the discovery of bed linen, towels, chemise, skirts, mattresses and blankets, etc, which have stains.
Obstetrical and Gynecological Stains
– this refers to waste materials discharge from the body especially feces. (Merriam – Webster, 1928)
Adults – Yellowish Brown
Infants – Greenish Yellow
Excrement
– this refers commonly to as a pigmented coating. Paint can revel vital evidence for the forensic scientist as it is present in many surfaces.
Paints
– this resemble bloodstains, reddish – brown in color, insoluble in water and soluble in dilute acid.
Rust Stains
– this resembles old bloodstains but can be recognize by treating strong acids and alkaline.
Synthetic Dyes
– this resembles blood that may be produced by fruits juices and vegetables.
Stains of Vegetable and Fruits Origin
