1. Lab: Blood Samples

2. In your lab notebook, choose 4 different slides of blood samples and draw and label what you see at 400X.

3. Blood

4. Blood Evidence Blood typing = class evidence
DNA profiling = individual evidence
Blood-spatter: recreate crime scene

5. History of the study of blood
2500 B.C.
Egyptians - bloodletting to cure diseases
500 B.C.
Greeks – distinguished between arteries and veins
1659 A.D.
Leeuwenhoek – view blood cells with microscope
1795
First blood transfusion performed
1901
Landsteiner – discovered 3 blood types (A, B, O)

6. 1902
Decastello – discovered AB blood type
1922
Oliver – established blood donor service
1935
Mayo Clinic – developed a method to store blood for transfusions
1900s
Kastle – developed first presumptive blood test
1959
Belgian Congo – first AIDS case recorded
1984
Gallo – identified virus causing AIDS
Development of blood-screening tests for infectious disease

7. Composition of Blood Cells (45%) Plasma (55%) red blood cells (RBC)
white blood cells (WBC)
Platelets
Plasma (55%)
90% water
Dissolved proteins (antibodies, hormones, clotting factors)
Nutrients (O2, glucose, amino acids, salts, minerals)
Wastes (urea, CO2)

8. Red Blood Cells Erythrocytes carry gases (oxygen, carbon dioxide)
produced in bone marrow
no internal organelles (no nucleus)
hemoglobin is iron-containing protein that binds to O2
gives blood the red color

9. White Blood Cells Leukocytes fights disease and foreign invaders
produced in bone marrow
true cell – has nucleus

10. Platelets
Tiny cell fragments
Helps in blood clotting

11. Kastle-Meyer Presumptive Blood Test

12. If blood is present, swab will turn PINK.
Procedures
Wet cotton swab with distilled water and gently rub on stain
Ethyl alcohol: breaks open cells, exposes hemoglobin
Phenolphthalein (Kastle-Meyer Reagent): reducing agent; turns pink when oxidized
Hydrogen peroxide: reacts with hemoglobin
If blood is present, swab will turn PINK.

13. False Positives
Some non-blood substances can yield a positive Kastle-Meyer test:
vegetables with peroxidases (potatoes, beets, horseradish, broccoli, cauliflower)
copper and nickel salts

14. Blood Typing

15. Why do blood typing? Less expensive and quicker than DNA profiling
Class evidence
Can be used to link or exclude suspect to crime scene (but doesn’t prove guilt)

16. Discovery of Blood Types
Karl Landsteiner (1901)
Blood from one person did not always mix freely with another person
Clumping of mixed blood results in death
Cell-Surface Proteins (RBC’s):
A and B proteins
Rh factor proteins
Antibody reaction test used to identify blood types

17. ABO Blood Types 42% 12% 3% 43% Type A: has A antigen on surface of RBC
Type B: has B antigen
Type AB: has both A & B antigens
Type O: has no antigens on surface

18. Antibodies
Our bodies have the ability to recognize between own cells (self) and foreign invaders (non-self)
White blood cells engulf and digest invaders
Antibodies: Y-shaped proteins secreted by WBC’s which aid in immune response
Antibodies bind to antigens (foreign substance or cell that reacts to antibodies)

19. Antibodies Type A: makes anti-B antibodies
Type B: makes anti-A antibodies
Type AB: no antibodies
Type O: makes anti-A and anti-B antibodies

21. Antigen-Antibody Response
Immune system attacks and destroys foreign invaders:
WBC’s make antibodies that attach to foreign proteins
WBC’s engulf invader
Agglutination: clumping of blood cells

22. Rh Factor
Rh protein found on RBC’s when Alexander Weiner worked with Rhesus monkeys (1940)
Rh+ : 85%
Rh- : 15%

23. Blood Typing Analysis

24. Blood Typing Analysis Blood sample mixed with 3 antibodies
If blood clumps, proteins are present
If no clumps, no proteins are present
Anti-A antibody test
Rh antibody test
Anti-B antibody test

25. Other forms of identification
Additional enzymes and proteins have been found in the blood:
Phosphoglucomutase (PGM)
Adenylate kinase (AK)
Adenosine deaminase (ADA)
Esterase D (EsD)
Glucose-6-phosphate dehydrogenase (G-6-PD)
Polymorphic proteins: Group-specific Components (Gc) and haptoglobins (Hp)