Forensic Serology/Forensic Biology PDF

MODULE FORENSIC CHEMISTRY AND TOXICOLOGY CHAPTER 3: FORENSIC SEROLOGY/ FORENSIC BIOLOGY Objectives: a) Understand the nature of blood and be able to determine the origin of blood by conductin...

MODULE FORENSIC CHEMISTRY AND TOXICOLOGY CHAPTER 3: FORENSIC SEROLOGY/ FORENSIC BIOLOGY Objectives: a) Understand the nature of blood and be able to determine the origin of blood by conducting various test b) Demonstrate skill in collecting, preserving, and transporting of blood specimen. c) Understand Forensic Serology and apply skill on proper handling and examining seminal fluids. THE NATURE OF BLOOD ❖ Blood – is highly specialized circulating tissue consisting of cells, enzymes, proteins, and inorganic substances suspended in fluid medium. o Volume: About 8% of total body weight 5 to 6 liters (Male blood) 4 to 5 liters (Female blood) o Components of Blood: Plasma (55%) - fluid portion composed principally of water and other constituents such as enzymes, glucose, etc. Cells (45%) – solid portion consist of red blood and white blood cells and platelets. RBC (erythrocytes) – carry respiratory gases and give it its red color because they contain hemoglobin – an iron-containing protein that binds oxygen in the lungs and transport it too tissues in the body. WBC (leukocytes) – fight disease. Platelets (thrombocytes) - cell fragments which play an important part in the clotting of the blood. 1|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY o Blood Loss: 40% loss, internally or/ and externally, is required to produce irreversible shock (death). blood loss of 1. 5 liters, internally or externally, is required to cause incapacitation. o Blood Clotting: when a protein in the plasma called fibrin traps and enmeshes the red blood cells, the blood clots forming solids that separates the serum. Serum – is the remaining pale-yellowish liquid when the clotted material where removed from the blood. This yellow liquid contains certain protein known as antibodies. The serum that contains antibodies was called – antiserum. BLOOD GROUPING History of Blood Grouping physicians have tried to transfuse blood from different blood from one individual to another. Their attempt often ended in failure Before 20th century because the transfusing sed blood tended to coagulate in the body of the recipient causing an instantaneous death Karl announced typing of blood. This classification also called the A-B-O Landsteiner system. On 1930, he received a Nobel prize award for his work in (1901) blood typing Rhesus (Rh) another blood factor discovered. At present more than 100 different factor (1937) blood factors shown to exist Until early forensic scientist uses blood factor technique in linking blood to the 1990s person originates this blood 2|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY o In theory, no two individuals except for identical twins, could be expected to have the same combinations of factors. o A-B-O SYSTEM: classification of blood based on the presence or absence on inherited antigen on the surfaces of red blood cells (RBCs). o Antigens are defined as substances recognized by the body to produce an antibody to react specially to it o Antibody is a protein that destroys or inactivates a specific antigen. Usually denotes using the prefix “anti”. ❖ PETER J ADAMO THEORY o Blood type A – folk had ancestors that were farmers, hence they ought to be vegetarians and shun meat and dairy products. o Blood type B – folk had descendants that were nomads, hence they should eat red meat and fish. o Blood type O – had ancestors that were hunters and gatherers, hence they should have lots of animal protein and little carbohydrates. o Blood type AB – mixed ancestry, hence they should have a combination of type A and type B. ❖ Test for the presence of blood A. PRESUMPTIVE TEST FOR BLOOD 1. Spot test Procedure Result Remarks Benzidine test Add 3 drops of Blue An enzyme hydrogen coloration peroxidase in peroxide to blood causes blood stain then the benzidine to add benzidine be oxidized to a reagent polymer which is blue colored. Kastle-Meyer/ First a few drops Sample Phenolphthalein phenolphthalein of ethanol, then turns and hydrogen test a few drops of violet peroxide react phenolphthalein with the and finally a few hemoglobin in drops of the blood; the hydrogen alcohol peroxide are behaves as a dripped onto the solvent. sample. Guaiacum test/ A drop on Blue Do not react Van Deen’s tincture of coloration tovery old stain day’s or guaiac, but sensitive to Schonbein’s turpentine and 1:50T test ether of hydrogen peroxide. 3|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY Hemastix Test strip used Color- Test kit for for field test of bands blood blood by are moistening with present distilled water and placed in contact with blood. Luminol test This is viewed Bright A spray reagent under ultraviolet blue used to test for lamp producing the presence of bright violet blood is not coloration. visible under ordinary light. Leucomalachite Leucomalachite Malachite Not a sensitive green test reagent and green or as benzidine (Adler 1904) hydrogen peacock test. peroxide is blue Leucomalachite added to blood. is oxidized to malachite green. 2. Microcrystalline Procedure Result Remarks Test Teichmann/ Salt and acetic is Reddish Crystals of Hemin added to stain and brown hemin or crystal test acid is allowed to rhombic/ hematic evaporate. prismatic crystals crystals Takayama test / Add Takayama Large rhombic Test for Haemochromogen reagent to stain crystals with hemoglobin crystal salmon color Acetone-Haemin or Acetone and Small dark Wagenhaar Test oxalic dichroic crystals 4|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY B. CONFIRMATORY TEST FOR BLOOD 1. Microscopic Exam – examination of menstrual blood corpuscles to differentiate mammal blood to other animals 2. Spectroscopic method – characteristic absorption band to Frauen Holfer lines ❖ Test to determine whether the blood is of human origin Test Procedure Result Remarks Precipitin test Use human blood and Blood Blood stain rabbit to create agglutinates dried as long sensitized rabbit as 10 -15 serum. This will form a years or more precipitin band on the may still give junction between the a positive serum and human precipitin blood being tested reaction. Gel diffusion Using agar subjected Blood to electrical potential forming line or bands of reacted antigen and antibody Electrophoresis An electrical potential to a gel medium until antigen and antibody reacts 5|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY COLLECTION, PRESERVATION AND TRANSPORT OF BLOOD SPECIMEN ❖ Blood is a perishable substance; thus, it is essential that proper collection and preservation were given attention so as not to destroy the evidence. ❖ Liquid sample should be placed on a sterile container and the stopper was sealed with a masking tape. ❖ Dried stains in smooth surface should be scrape with a clean knife or razor blade and placed the scrapings in an envelope, pillbox, or folded paper pocket. ❖ Clothing containing stains should be air dried without sunlight (some component might damage by direct sunlight) and wrapped it with paper. ❖ If the blood is in soil, same is applied as in the collection of debris, put it in a glass container or new paint can and maintain individuality and chain of custody. 6|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY FORENSIC CHARACTERIZATION OF SEMEN ❖ Semen – viscid gelatinous, sticky character but after exposure teds to become more liquid due to enzyme action, normal quantity in a single ejaculation is 1.5 to 3.5 ml. This contain spermatozoa, epithelial cells and crystal choline and lecithin and slightly alkaline. Spermatozoa – healthy young man is about 400 to 500 ml Aspermia/ Oligospermia – sperm disease ❖ Examination of semen and seminal stains ❖ Physical examination: ▪ Microscopic examination - the sperm cell was stained and viewed under a high-power microscope. ▪ Ultraviolet examination – seminal stain exhibit bright bluish fluorescence. 7|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY ❖ Chemical examination ▪ Florence test – named after introduction of Dr Florence of Lyons, France for this test. Based on formation of choline periodize crystal, a dark brown rhombic or needle shape. Limitation for this test includes: If the specimen was not dried carefully destroying choline. If the specimen were mixed with blood. If the specimen contains too much albumen that interfere in the reaction. ▪ Barberios test – spermine picrate, a slender yellow tinted rhombic needle with obtuse angles and sometimes appeared as ovoid crystals. ▪ Acid phosphatase – Dr Sidney Kaye, a specific sperm test for human, forming orange-ed pigment (a naphthylamine and Fast blue B reagent) NOTE: the more semen, the deeper the purple 8|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY FORENSIC ENTOMOLOGY ❖ Forensic entomology is a branch which makes use of insects in the detection of crime and used to calculate the time since death. ❖ Why used insects in death investigation? ▪ Insects are generally the first to discover a corpse. ▪ Insects arrive at a decomposing corpse in somewhat predictable sequence “ecological succession” ▪ Often insects are ignored or even discarded as evidence at a death scene or autopsy. 9|Page  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY ❖ BLOW FLY LIFE CYCLE Adult female blow flies arrive within minutes to lay eggs on a cadaver. Each deposit about 250 eggs in the natural openings of the body and open wounds. The eggs hatch into first-stage maggots within 24 hours. These feeds and then molt into second-stage maggots, which feed for several hours, and then molt into third-stage maggots. Masses of third-stage maggots may produce heat, which can raise the temperature around them more than 10° C. After more feeding, the third-stage maggots move away from the body and metamorphize into adult flies. ❖ It can be divided in three subfields: urban, stored-product and medico-legal/ medico- criminal. ▪ Urban forensic entomology concerns pest infestations in buildings or gardens that may be the basis of litigation between private parties and service providers such as landlords or exterminators. ▪ Stored-product forensic entomology is often used in litigations over infestation or contamination of commercially distributed foods by insects. ▪ Medico-legal forensic entomology includes arthropod involvement in events such as murder, suicide, rape, physical abuse and contraband trafficking. In murder investigations it deals with what insects lay eggs when and where, and in what order they appear in dead bodies. This can be helpful in determining the time or postmortem interval (PMI) and location of the death in question. 10 | P a g e  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY ❖ HISTORY OF FORENSIC ENTOMOLOGY Sung Tz’u – Chinese death investigator wrote a book entitled “The Washing Away of Wrongs” probably the first actual medico-criminal 1235 AD entomology case was recounted. A murder by slashing occurred in Chinese Village, and the local death investigator was deputized to solve the crime. After some fruitless questioning, the investigator had all villagers bring their sickles to one spot and lay them out before the crowd Flies were attracted with one of the sickles, probably because of invisible remnants of tissue still adhering to it, and the owner subsequently broke down and confessed to the crime In other portions of the text, Sung Tz’u demonstrated knowledge of blow fly Insects of forensic importance is activity of bodies relative to those orifices necrophagous (corpse-eating). This is infested, the time of such infestation, and outlined by Mostovski and Mansell. The the effect of trauma on attractiveness of order in which the insects feed on the tissue in such insects corpse is called the faunal succession 11 | P a g e  MODULE FORENSIC CHEMISTRY AND TOXICOLOGY References: Viccelio, Peter, Emergency Toxicology, 2nd Edition, Lippincott-Raven Publishers, 227 East Washington Square, Philadelphia, 1998 Sunico, Lorenzo A, Forensic Chemistry, NBI, Manila. Saferstein, Richard D, Criminalistics: An Introduction to Forensic Science, 2001. Prentice Hall, Upper Saddle River New Jersey Eckert,William, G, Introduction to Forensic Sciences, CRC Press, New York 1997 https://www.nlm.nih.gov/exhibition/visibleproofs/galleries/technologies/blowfly.html LINKS TOPIC LINK FOR VIDEO Human Blood Video | Blood https://www.youtube.com/watch?v=qrE6Y0Se8bw Components | Blood Cells https://www.youtube.com/watch?v=_Mum9z- Structure of a Sperm Cell 8kks Forensic entomology | The crime scene https://www.youtube.com/watch?v=HIVKISCmjTQ 12 | P a g e