Drugs, Detectives and DNA
Author: | Patricia Ligon |
Level: | High School |
Content Area: | Chemistry, Biotechnology, Forensics |
Author: | Patricia Ligon |
Level: | High School |
Content Area: | Chemistry, Biotechnology, Forensics |
Lesson Plan 1
Lesson Plan 2 - Body Fluids
Lesson Plan 3- Blood
Lesson Plan 4
Resources:
Websites:
There are four major fields of anthropology, which is the study of humans and their works:
Traditional means of identification from unknown remains includes:
Anthropological Analysis includes the following questions:
Forensic anthropological services are required not only to identify a individuals but especially in cases of mass graves, e.g. Bolivia, plane crashes and variously decomposed or destroyed bodies. These notes on Anthropology are based on a lecture by Dr.Ted Rathbun from the University of South Carolina. His mentor is Bill Bass of the "Body Farm" where the decomposition of human bodies under various environmental conditions is studied.
Human Skeleton notes (from Dr. Laura Vick, Peace College, Raleigh, N.C.)
Crime scene scientists can almost break the silence of the dead with special techniques that determine the age, ancestry, and gender of skeletons from the recent or ancient past. Notes from Dr. Stephen Nawrocki, consultant to the Dept. of Natural Resources and crime investigators; discuss his experiences in the field of forensic anthropology.
Date: November 5, 2002
Location: Indiana Medical History Museum Amphitheater
Speaker: Stephen R. Nawrocki, Ph.D.
Before a packed house in the 100+ year old lecture hall at the Indiana Medical History Museum, Dr. Stephen Nawrocki gave a fascinating slide presentation on his work in forensic anthropology. As the only Board Certified Forensic Anthropologist in the State of Indiana, Dr. Nawrocki has participated in a number of intriguing cases where the science of forensic anthropology enabled bones to "break their silence" and tell the world who they were, when they died, and even the circumstances of death.
Originally this lecture was subtitled "Helping Victims Speak," but forensic anthropology is not just about criminal investigations. For example, identification techniques are allowing families to finally bury the long-missing remains of loved ones who died in the Vietnam War. When asked about the oldest bones he had worked with, Dr. Nawrocki talked about the delicate recovery of the 6000-7000-year-old skeletal remains of a woman buried along a now-eroding river bank.
Internet Resources for Physical Anthropology ( http://www2.lib.udel.edu/subj/anth/phys/internet.htm):
The function of blood and body fluids is to transport nutrients, metabolites (waste products), A, B and Rh antigens, proteins, hormones, salts (electrolytes), sugars, and dissolved gases (e.g. oxygen and carbon dioxide). In addition, drugs, medicines, enzymes and neurotransmitters are transported via the blood. Drugs can include: nicotine, THC (Marijuana), LSD (Lysergic Acid Diethethylamide), heroine, cocaine, methamphetamine, alcohol, and ecstasy. Toxicology tests can identify these and other drugs. Transported neurotransmitters can include: dopamine, serotonin, GABA (Gamma Amino Butyric Acid), vasopressin, acetylcholine and epinephrine.
Blood is composed of 55% plasma and 45% blood cells. Red blood cells contain hemoglobin, which primarily carries oxygen and carbon dioxide. Red blood cells contain no nuclei, while white blood cells and platelets do contain nuclei. White blood cells kill foreign bacteria as part of the immune system. Platelets are used in blood clotting. Hematocrits measure the percentage of blood cells in the blood.
The main blood types are A, B, AB, O and Rh factor. Many of these blood factors can be easily identified. DNA testing uses the DNA from the blood cell nuclei (i.e. cells other than red blood cells). Spinning the blood separates the blood cells from the plasma. Plasma is a straw-colored part of the blood which is 90% water and 10% nutrients, metabolites (waste), electrolytes, mostly Na+, Cl- HCO3- and proteins).
The ABO System of Blood Typing
A, B, and Rh factors in blood are important in forensic serology because it can be done quickly and relatively inexpensively. Identification of blood type can indicate the identity of a suspect or a victim. Then further, more expensive tests, e.g. DNA fingerprinting, can be done to confirm the identify of the person. About 80% of the population is secretors which means that their blood type antigens are found in body fluids other than blood: therefore other fluids can also be used in identification.
Blood cells are covered with polysaccharides known as antigens which react with antibodies found in blood serum (plasma) causing blood cells to coagulate in an agglutination reaction like a chemical precipitation reaction. There are 2 basic antigens: A and B. There exist antibodies to the two antigens, A & B. A person's Red Blood Cells can have either, both or none of these antigens resulting in a variety of blood types (e.g. A, B, AB, or O blood types). The purpose of the antibodies in the blood serum is to attack invaders that enter the blood system, e.g. viruses or bacteria. Thus, a type A person produces anti-B antibodies or anti-B serum that destroys type B blood cells and vice versa. Type O has both anti-A and anti-B antibodies in its serum while type AB has neither type A or B antigens on the surface of its blood cells. Using the wrong blood type can be fatal in blood transfusions and organ transplants as in the case of Jessica Santillan at Duke Hospital. Rh factor is sometimes referred to as the D antigen. Rh+ people have the factor and Rh- do not. About 85% of the general population has the Rh factor. Generally 41% of a population are type A, 10% type B, 4 % type AB and 45% type O. Type O is the universal donor blood type, and type AB is the universal receiver blood type.
Examples of Blood Type Testing:
Agglutination, i.e. a reaction between antigen and antibody which causes clumping of the blood cells, occurs where there is a + sign in the table in this lab activity.
Blood Group | Antigens | Antibodies | Can Give Blood to: | Can Receive Blood from: |
AB | A and B | None | AB | AB, A, B, O |
A | A | B | A and AB | A and O |
B | B | A | B and AB | B and O |
O | none | A and B | A, B, AB and O | O |
Blood tested with Rh factor antibody | ||||
Rh+ | + | |||
Rh- | - |
Potential problems can occur between an Rh negative mother and an RH positive baby. Late in pregnancy, some of the baby's blood may cross over into the mother's blood. The mother's body will make anti-Rh factor, which is not a problem in the first pregnancy but could be in successive pregnancies. So, the mother is injected with anti-Rh antibodies to eliminate the Rh antigen before her own immune system responds and generates immunological memory against the Rh factor, which would endanger any of her future Rh positive babies.
VACCINES:
Knowledge of the antibody antigen system an lead to the development of vaccines for a variety of illnesses. Vaccines can be just another antigen. The immune system is always activated, so that means that white blood cells are always scavenging the blood for foreign substances. Vaccines push the immune system to have a strong response to a particular antigen, e.g. polio and pertussis (whooping cough). A vaccine is made from an inactivated, normally harmful substance. The simple Tetanus vaccine is created by heating the Tetanus toxin and incorporating the inactivated toxin into the vaccine. More complex organisms like viruses or bacteria have tens or hundreds of thousands of different proteins. Usually one good protein will make an effective vaccine, e.g. hepatitis B.
BODY FLUIDS:
Body fluids can be saliva, mucous, semen, vaginal fluid, breast milk, or urine. These body fluids transport nutrients, metabolites (waste products), A, B and Rh antigens, proteins, hormones, salts (electrolytes), sugars, and dissolved gases (e.g. oxygen and carbon dioxide). In addition, drugs, medicines, enzymes and neurotransmitters are transported via the blood. There exists a secretory gene (Se) which is found in about 80 % of the population independent of blood type, i.e. a person could be type A and Se or type B and Se. This gene interacts with blood type genes and determines your ability to secrete your blood type antigens into body fluids other than blood. In other words, secretors put blood type antigens into the blood and body fluids while non-secretors put little to no blood type antigens into other body fluids. Persons who are secretors can have their body fluids tested for blood type. Secretors tend to have stronger immune systems, therefore it is better to be a secretor than a non-secretor.
Urine is 95% water and 5% other dissolved or suspended substances including metabolites (waste products), drugs, medicines, A, B and Rh antigens, proteins, hormones, salts (electrolytes) and sugars. A person produces 0.6 to 2.5 liters of urine daily depending on the person's intake and environment, i.e. temperature and humidity. If a person is diabetic, their urine may contain high levels glucose. The presence of protein in the urine can indicates some type of illness.
Resources and references:
Website:
http://nobelprize.org/medicine/educational/landsteiner/readmore.html