Forensic Serology Out damned spot Out I say

Forensic Serology “Out damned spot! Out, I say Here’s the smell of the blood still, All the perfumes of Arabia will not Sweeten this little hand. Oh, Oh!” —William Shakespeare’s Lady Macbeth, in Macbeth Chapter 10

Using Blood in Forensics S Test for blood type S Provides DNA evidence S Analyze bloodstains S Blood spatterns S Livor mortis- pooling of blood in dead organisms Chapter 10

Karl Landsteiner S In 1901 he discovered that all humans do not have the same blood type S He discovered the A-B-O blood group system S This saved millions of lives by preventing mismatched blood transfusions S Other researchers were able to discover the Rh factor because of his research S 29 years later, they gave Karl a Nobel Prize Chapter 10

Serology is the examination and analysis of body fluids. A forensic serologist may analyze a variety of body fluids including saliva, semen, urine, and blood. From 1950 to the late 1980’s, forensic serology was a most important part of lab procedures. With the development of DNA techniques, more time, money, and significance was placed in developing DNA labs. However, with limited funds and the time required for DNA testing, most labs still use many of the basic serology testing procedures. Chapter 10

Blood and Forensics Chapter 10 S No 2 individuals (except identical twins) can share all the 100+ blood factors S So forensic scientists used this tool to link blood from a crime scene to an individual

Role of blood in the human body S 1. Blood is a fluid connective tissue S 2. Transportation S It transports oxygen, carbon dioxide, nutrients, wastes, water, ions, and minerals S 3. Regulation S Hormones (to regulate body functions) S Heat (to regulate body temperature) S 4. Protection S Clotting protects against blood loss S Provides immunity to many diseases Chapter 10

What is Blood? 3 Cell Types + Fluids: • Erythrocytes (Red Blood Cells) • Leukocytes (White Blood Cells) • Platelets (Cell fragments) • Plasma

White Blood Cell Platelets Red Blood Cells

Characteristics of Red Blood Cells n Red blood cells (erythrocytes) are biconcave disks that contain the oxygen-carrying protein hemoglobin.

Characteristics of Red Blood Cells n In addition to 100 s of cell surface proteins, their cell surfaces have a special class of blood factor proteins called Antigens. n There at least 15 different antigens, but the most important are the ABO and Rh antigens

Role of RBCs n Transport cells inhaled O 2 from lungs to all body – O 2 + hemoglobin = bright red blood n Remove CO 2 from all body cells and take it back to lungs for exhalation – CO 2 + hemoglobin = dark red blood n RBCs are destroyed after about 120 days

Summary of Functions of WBCs l Leukocytes can squeeze between cells lining walls of blood vessels and attack bacteria and debris. l Neutrophils and monocytes are phagocytic (cell killers). l Eosinophils moderate allergic reactions as well as defend against parasitic infections. l Basophils migrate to damaged tissues to promote inflammation and to inhibit blood clotting. l Lymphocytes are the major players in specific immune reactions and some produce antibodies (T cells and B cells)

Blood Platelets n Blood platelets are fragments of cells n Platelets help repair damaged blood vessels by adhering to their broken edges. n Thrombopenia, or low platelet counts increase bleeding risks n Thrombocytosis or high platelet count may lead to thrombosis (clotting, bruising, strokes, heart attacks).

Blood Clotting n The blood clots when the protein FIBRIN traps and meshes RBC’s together. n SERUM is a yellow liquid that remains after the RBC’s clot.

Blood Clotting and Forensics n The clotting process begins 3 -15 minutes from injury. – 1 st forms dark, shiny, jelly-like mass – 2 nd begins to contract and separate from serum. n How long ago did the victim begin bleeding? – A few minutes: Blood is still liquid – Less than an hour: Blood is shiny, gelantinous, in a pool. – Several hours: Blood has separated into clot and serum

Hematocrit means the percentage of red blood cells in blood. Scientists use a centrifuge to separate the parts of blood based upon density of the parts. n A blood hematocrit is normally 45% cells and 55% plasma.

Blood Plasma • Plasma is the clear, straw -colored fluid portion of the blood. • Plasma is mostly water, with a mixture of, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes

Buffy Coat? Buffy coat is the layer that contains most of the white blood cells and platelets. “Buffy” because it is buff (color of naked skin) in color The buffy coat is used to extract DNA from blood - RBCs have no DNA, only WBCs do.

ABO Blood Group n Antigens are on red blood cells and antibodies are in the plasma. n Adverse transfusion reactions are avoided by preventing the mixing of blood that contains matching antigens and antibodies. – Adverse reactions are due to the agglutination of red blood cells.

Blood Groups and Transfusions Antigens and Antibodies n Clumping of red blood cells following transfusion is called agglutination. n Agglutination is due to the interaction of proteins on the surfaces of red blood cells (antigens) with certain antibodies carried in the plasma.

Rh Blood Group n The Rh factor was named after the rhesus monkey. n If the Rh factor surface protein is present on red blood cells, the blood is Rh positive; otherwise it is Rh negative. n There are no corresponding antibodies in the plasma unless a person with Rh-negative blood is transfused with Rh-positive blood; the person will only then develop antibodies for the Rh factor.

Blood Groups Antibody Can Give Can Get Blood From Type Antigen A A B A, AB O, A B B A B, AB O, B AB A and B Neither A nor B AB A, B, O, AB O Neither A nor B A and B A, B, O, AB O Blood To Universal Donor is O, Universal Recipient is AB.

Agglutination of RBCs

Population Distribution of Blood Types in the U. S. Type Percent O 45 A 40 B 11 AB 4

Relative Frequency of Blood Types in Human Populations

• Genotype: describes the allelic pair combination • Phenotype: describe the trait/characteristic expressed

Genetic Blood Typing (Genotypes) Mother Father A B O A AA AB AO B AB BB BO O AO BO OO

Transmission of our traits Allele Combinations Blood Type (phenotype) AA + AO A BB +BO B AB AB OO OO

Paternity Testing • Human leukocyte antigen (HLA) is used in paternity testing. • If a man and child share the HLA markers there is a 90% probability that the man is the child’s father. • The Haptoglobin marker + ABO + HLA increases the probability to 95%

DRUG - DETECTION Hypothesis: Since foreign substances in blood are identified and then isolated by the immune system, it should be able to detect the presence of drugs and other chemicals. This hypothesis is incorrect. The immune system only creates antibodies and launches attacks against foreign proteins (either free proteins or ones bound to cells) and not against other chemical compounds.

We can fool the immune system n n n The drug can be attached to a carrier molecule that is a protein This drug-protein combo can be injected into an animal such as a rabbit or rat (no human volunteers) The animal’s immune system will create antibodies that are specific to the shape of this drug-protein combo molecule We can isolate these antibodies from the animal’s blood serum And use these antibodies to detect the presence of the drug in human blood or urine

Now how does a criminalist use these antibodies? l l l To detect drug presence in blood, urine, etc. A. K. A. EMIT assays (bio jargon for test) EMIT stands for Enzyme-multiplied Immunoassay Technique EMIT is most often used to test for marijuana (THC) metabolites in urine. One of the primary THC metabolites is THC-9 -carboxylic acid

Questions for a Criminalist: Is it blood? 2. Is it human blood? 3. If it is human, can it be linked to a suspect / victim and how closely? 1.

The Kastle-Meyer Test to ID Blood (tests for hemoglobin) l Phenolphthalein = colorless l Blood+ phenolphthalein + hydrogen peroxide = bright pink because of hemoglobin l This test can yield some false positives l Certain vegetable matter can produce the bright pink positive (such as potatoes)

Death By Potato? n Although the Kastle. Meyer test can give a false positive in the presence of certain plant matter, it is unlikely that this plant matter would be present at a crime scene and be mistaken for blood.

Other blood detection tests n Doctors use Hemastix© strips to detect blood in urine, but these strips can be used at a crime scene to detect fresh or dried blood. n Moisten them with distilled water and wipe the bloodstain. A color change to green is a positive indicator of blood

Bayer Hemastix©

Luminol n n n Luminol is a chemical that exhibits chemiluminescence, with a striking blue glow, when mixed with an appropriate oxidizing agent. It is a white to slightly yellow crystalline solid that is soluble in water and most polar organic solvents. Usually, a solution of hydrogen peroxide (H 2 O 2) and a hydroxide in water is used as the activator. In the presence of a catalyst such as an iron compound, the hydrogen peroxide is decomposed to form oxygen and water:

What do you see with luminol? It glows a bright blue in the dark, when it comes in contact with bloo

Advantages of using Luminol Allows one to detect stains that would not be ordinarily be visible n Extremely sensitive - can use it in very dilute concentrations n This allows the CSI to spray large areas with it n It does not interfere with DNA, so a CSI can collect samples for DNA analysis even after it was sprayed with luminol. n

Bloody Footprints that were wiped

Drawbacks n n Luminol glows even in the presence of certain other fluids – semen, feces, bleach, tonic water, etc. Luminol glows in the presence of certain vegetable matter - Mr. Potato head strikes again!

Thanks to Quinine

So we know its blood – but is it human? n The Precipitin Test – Rabbits injected with human blood – They make antibodies in their serum – They are bled and the serum recovered – The serum is called human antiserum, because it will react to human antigens – It will cause coagulation when mixed with human blood

Precipitin Test (Human blood) (Human antiserum made in rabbits)

Is it human blood? n Human Blood n Frog Blood

Gel Diffusion Test n Antigen (blood) and antibodies (human antiserum from rabbits) are placed in separate wells in a gel. n They are forced to move towards each other. If they bind to each other, they form a single line of precipitate in between the wells n This is a positive for human blood

DNA TEST n DNA testing is the ultimate for learning as much as possible about a blood sample. n It has made many other tests obsolete.

Sources n n n Dizengoff, La Guardia High School Kendall Hunt, Forensics for High School Fundamentals and Investigations, Cengage Forensic Science, Saferstein www. bio-guru. com www. cohs. com