CHM 1020c Exam 4- FSU Dillon

Poisons are

compounds that when ingested, absorbed, injected or inhaled cause disruption of normal body function usually through chemical reactions or activities on the molecular scale

The lethality of poisons is given on a scale called the

LD50

LD50 is

dose that will kill 50% of the test population

There are four pathways by which poisons enter the body:

Ingestion (Gastrointestinal Tract)

Inhalation (Lungs)

Dermal/Topical (Skin)

Injection (intravenous, intramuscular, intraperitoneal)

The speed with which a poison can act is dependent on the

pathway it takes into the body.

The pathways are listed below from fastest to slowest:

Intravenous (into a vein) injection > inhalation > intraperitoneal (into the body) injection > intramuscular (into the muscle) injection> ingestion > topical (onto the skin) absorption

Acute

< 24hr

usually 1 exposure

Sub-acute

1 month

repeated doses

Sub-chronic

1-3 months

repeated doses

Chronic

> 3mo

repeated doses

Once the poison is in the body,

it has to overcome or avoid the body's natural defenses and translocate to the area in which it will act.

When inhaled a poison is in gas form and uses

the body's blood stream to move through the body as absorbed gases though the alveoli.

When ingested the poison is

absorbed through the GI tract and small intestine.

When absorbed through the skin the toxin passes

first through the pores, then into the subcutaneous tissues and then finally into the blood stream.

Distribution refers to

how the poison is translocated through the body once absorbed. In most cases, transport occurs through blood flow.

The rate of distribution is therefore dependent on

blood flow and the chemical characteristics of the poison.

If the poison is not acute,

then the poison must build up over time

rage in adipose tissue (fat) will occur for

those chemical compounds that are non-polar in nature.

Chemicals that are similar in nature to Calcium- e.g. Fluoride (F), Lead (Pb), and Strontium (Sr) find chemical pathways that will

imbed them into bone using the body's natural bone building apparati.

Those organs like the liver, kidneys and lungs have very high blood flow and are therefore more

susceptible.

At the cellular level, the poison can

interfere with receptor-ligand binding

interfere with membrane function

interfere with cellular energy production

bind to biomolecules

perturb homeostasis

Toxins are

poisons that are produced by natural biological function; e.g. a snake's venom.

Heavy metals are

the transition metals found in the periodic table.

There are three main types of toxin:

Neurotoxins

Cytotoxins

Hemotoxins

Neurotoxins affect the

nervous system

cytotoxins affect

cells

hemotoxins effect

blood and organs

Some chemicals that fall into the category of a neurotoxin are listed below:

Lead

Ethanol (drinking alcohol)

Glutamate

Nitric oxide (NO)

Botulinum toxin (e.g. Botox)

Tetanus toxin

Tetrodotoxin (Pufferfish Toxin)

The neurotoxin causes death by

binding to and keeping nerve cells from performing their normal activities

A cytotoxin is

any compound or molecule that has a toxic effect on cells

Hemotoxins are

those that destroy red blood cells

The venom itself is what is called a

metalloproteinase

Heavy metals are

transition metals found in the middle of the periodic table that are of environmental or physiological concern.

The most important heavy metals that can be and have been used as poisons are

lead(Pb)

mercury(Hg)

arsenic(As)

cadmium(Cd)

iron(Fe).

The toxic effects produced by heavy metals are accomplished by

binding to one or more reactive groups essential for normal physiological functions.

Mercury is

a metal that is a liquid at room temperature. It has three highly toxic forms: elemental (Hg liquid or vapor), compounds of inorganic salts (e.g. Hg(NO3)2, and organometallics (e.g. CH3Hg).

Mercury can enter the body by a number of different methods:

Inhalation

Ingestion

Absorption through the skin (organomercury)

Mercury ions produce toxic effects by

protein precipitation, enzyme inhibition, and generalized corrosive action

Once bound to mercury,

most proteins are rendered inactive.

mercury binds irreversibly to an enzyme (proteins that create molecules) changing its

conformation and preventing its normal substrate (molecule it works on) from binding.

Lead is normally ingested through

contaminated water or food.

Lead can interfere with the normal operation of hemoglobin,

adversely affect the Central Nervous System (CNS) and causes developmental issues in children.

Lead affects the production of Heme by

binding to and blocking the enzyme ALA-D.

The reduced amount of Heme (the oxygen carrying molecule in blood) leads to

Anemia

Cadmium (Cd) is

a metal found in Coal and released into the environment as coal is burned

Cadmium is most toxic in its ionic form

Cd2+

The normal pathway by which cadmium finds its way into the body is through

consumption.

Cadmium acts as a poison by a number of pathways:

It acts like a catalyst to increase the formation of peroxides (O22-) in the body. Peroxides are damaging to tissues and organs.

It stimulates the production of molecules known as cytokines. These molecules cause inflammation (swelling).

It can modulate gene expression and hamper chromosomal signal transduction.

Arsenic, which often is described as tasting like bitter almonds, is generally taken into the body by

consumption or inhalation from smoke.

Arsenic kills by disrupting the biochemical pathways in the body that produce

ATP

Fingerprints are made from

sweat

Within the sweat are a number of chemical compounds:

Inorganic ions (Na+, Cl-)

Proteins, amino acids

Lipids

Water

it is the lipids (fats and oils) and amino acids that allow fingerprint residues to

last long enough for collection.

Lipids are also called

fats and oils

Lipid molecules are all based on the presence of fatty acids, which are

long carbon tails (16-20+ Carbons long) with a carboxylic acid (-COOH) group at one end.

The carbon tails may be

fully saturated (no double bonds) or may be mono- or poly-unsaturated (containing one or more carbon-carbon double bonds).

Phospholipids are

modified triglycerides, in which one of the fatty acid groups is replaced with a phosphate group (PO43-), making a polar head group.

Iodine (I) is an element in Group 7 in the periodic table and therefore a

Halogen

Iodine is a

solid at room temperature but sublimes (direct solid to gas phase change) to form a gas at relatively low temperatures

As a technique Iodine Fuming is

one of the simplest methods only requiring a hood or isolated area with good ventilation as the fumes are toxic and a heat source to sublime the iodine

Amino acids are

building blocks of proteins

Fingerprints are

the friction ridge patterns found on the fingers, palms, toes and soles of the feet. Fingerprints or prints in general are composed of ridges and valleys:

Black lines are ridges and

white lines are valleys.

Fingerprints are categorized by what is called

pattern and minutiae

The database called the Automated Fingerprint Identification System or AFIS is

used throughout the United States to search for comparison prints that have been logged into the system with identifying patterns and minutiae identified.

There are 3 types of fingerprints that can be collected and analyzed:

Visible - those prints that are made with substances like grease, paint, blood, etc. that are visible to the naked eye and do not need processing to be analyzed.

Impression - those prints that are made in wax, tar, butter etc. that can be lifted and analyzed without additional processing.

Latent - those prints that are invisible to the naked eye and must be processed before they can be analyzed.

Hair is

the fine threadlike strands growing from the skin of humans, mammals, and some other animals, while fibers are defined as the smallest part of a textile material

From hair you can determine:

Human or animal

Race

Origin

Manner in which hair was removed

Treated hair

Drugs ingested

Hair is composed of the protein keratin,

which is also the primary component of finger nails.

Hair is produced from a structure called the

hair follicle

In order to test hair evidence for nuclear DNA,

the root must be present

The hair may also be tested using

Mitochondrial DNA whether or not the root is present

The medulla is

the hair core that is not always present

Human medulla may be

continuous, fragmented or absent.

The Medulla Index is used to

compare hairs and to determine the type of hair found.

The index value is calculated by

measuring the diameter of the medulla and dividing it by the diameter of the hair.

Human hair has an index value around ⅓ while

animal hairs have an index value of around ½.

Almost all fibers are some form of

chemical polymer

Polymers are

chemical molecules with repeating units of structure.

Fibers are separated into two general categories:

Natural and Synthetic

Natural Fibers:

Cotton

Linen

Silk

Wool

Synthetic Fibers:

acetate, acrylic, nylon, polyester, rayon, blends

One of the simplest ways to identify fabric fibers that are unknown,

is a simple burn test

Blood is familiar as

the vehicle for oxygen transport from lungs to tissues, and for transport of CO2 generated during respiratory metabolism in tissues to the lungs for release

Blood transports

major organic nutrients from the intestine (where they are absorbed) to the liver (where they are processed) and ultimately to the other organs.

The human vascular system contains about

5 to 6 liters of blood

Nearly one-half its volume consists of cells:

red blood cells (erythrocytes), which transport oxygen and carbon dioxide, and much smaller numbers of white blood cells (leukocytes), and blood platelets, which are part of the defense (immune) system.

Every human cell requires a steady supply of

oxygen gas, O2.

Every cell also requires a way to dispose of

CO2

The non-cellular portion of blood is called the

blood plasma

Plasma is about 90% water by

weight

The plasma proteins make up

three-fourths of the weight of solutes in plasma

One mL of blood contains about

5 billion (5 x 10^9) erythrocytes.

There are 3 genes for different blood types:

A, B and O.

AA or AO =

Type A

BB or BO=

Type B

OO=

Type O

AB=

Type AB

This means for blood typing there are four major blood types

A, B, AB and O.

So now our 4 major blood types are further separated into 8:

A+ A-

B+ B-

AB+ AB-

O+ O-