Exam Three

Enzyme Linked Immunosorbent Assay (ELISA)

a widely used laboratory technique that detects and quantifies specific proteins, antibodies, and antigens within a sample

can be used to detect both antibody and antigen

very sensitive

relies on polyclonal and monoclonal antibodies

Antibody

protein secreted by B-cells (plasma cells) that specifically bind a foreign substance (antigen)

The Five Kinds of Naturally Occurring Antibodies

IgA

IgG

IgM

IgE

IgD

Direct Immunodetection

primary antibody conjugated with enzyme system

Indirect Immunodetection

secondary antibody conjugated with enzyme system

Sandwich Indirect Immunodetection

secondary antibody conjugated with enzyme system

antigen applied in soluble form

Indirect Immunodetection with Biotin Linkers

secondary antibody conjugated with enzyme system

biotinylated (streptavidin) primary antibodies

Polyclonal Antibodies

heterogenous mixture of antibodies derived from different B-cell lineages

made in goat, sheep, rabbit, or mouse

antigen is injected into animal, so plasma cells will secrete antibodies

antibodies collected from serum of animal

Blocking

filter out/remove unbound/non-specific substances

used 10% FBS for ELISA in lab

How Detection Occurs

absorbance read at 405 nm

Toxicology

study of poisons/toxins

sample is from the human body (blood, urine, gastric contents, vitreous humor, bile and liver, and breath among other sources)

involves how to analyze toxin, drug movement, metabolism, etc.

Seized Drug Analyst

studies drugs/toxins found outside the body

Forensic Toxicology

examination of all aspects of toxicology that may have legal implications (postmortem drug testing, workplace drug testing, and contraband materials)

Occupational Toxicology

deals with chemical hazards in the workplace

Liver

where toxins are metabolized in the body

causes the drug effect to wear off

Opiates

depressants derived from morphine that cause euphoria and analgesia

cause death by paralysis of the respiratory center

Amphetamines

stimulants that cause intense euphoria

controlled purchase limits

Cocaine

stimulant derived from the coca leaf (natural product)

Cannabinoids

psychoactive compounds causing euphoria, perceptive alterations, and memory impairment

THC as the psychoactive component that can be present in urine for two months following use

Ways Pharmaceutical Materials Cause Death

wrong drug

wrong dose

organ damage

intentional overdose

polypharmacy

Polypharmacy

lethal combination of drugs

Alcohols

ethanol, methanol, and isopropanol

enter the membranes of nerve cells and disrupt normal signaling

death concentration is 350 mL/deciliter

Cyanide

binds to ferric ions in cytochrome oxidase, interrupting the electron transport chain and energy generation

antidotes are ineffective due to rapid action

fatal levels are greater than 2500 ng/mL

Carbon Monoxide

causes more deaths than any other toxin

binds to hemoglobin meaning it cannot transport oxygen to tissues

rick of death if carboxyhemoglobin levels exceed 60%

Presumptive Toxicology Test

very sensitive although not necessarily specific

Confirmatory Toxicology Test

both sensitive and specific

DNA Profiling

a technique used by scientists to distinguish between individuals of the same species using only samples of DNA

can be used to solve crimes, find paternity, and investigate medical problems

can be done using blood, hair, saliva, semen, and body tissue cells

Stage 1 of DNA Profiling

cells are broken down to release DNA

PCR can be used to amplify DNA is only a small amount is available

Restriction Enzymes

break down DNA molecules to make them easier to study by cutting DNA at specific base sequences

come from bacteria where they are used to protect them against viruses

includes 4 or 6 base cutters

Stage 2 of DNA Profiling

the DNA is cut in fragments using restriction enzymes that cut at a specific base sequence

Restriction Fragments

the sections of DNA cut out by restriction enzymes

thousands yielded from DNA digestion

Stage 3 of DNA Profiling

fragments are separated based on size using gel electrophoresis

Gel Electrophoresis

DNA fragments are injected into wells and an electric current is applied along the gel

negatively charged DNA (phosphate group) is attracted to the positive end on the gel

the shorter DNA fragments move faster than the longer fragments, separating it on basis of size

Genetic Fingerprint/Genetic Profile

the pattern of bands in a gel electrophoresis