intro to forensics exam 2

forensic toxicology

study of drugs and poisons in biological samples

mathieu orfila

professor of forensic chemistry and dean of medicine

key figure in history of forensic science, toxicology, and death investigation

forensic toxicologists

role of __ __

analyze blood, tissues for drugs, poisons, and metabolites

work with ME or coroner to help determine manner and mechanism of death

metabolites

key components that make up a drug

xenobiotics

foreign substances not naturally found in the body

an umbrella term

drugs

compounds causing physiological events

poisons

substances causing toxic/damaging effects

any substance can be this if sufficient amount is ingested

blood

forensic toxicology screenings are most accurate from a __ sample but can also be done on urine samples

bloodstream

most overdoses occur once the drug hits the __

bloodstream

drug or other ingested substance must enter the __ to have generalized physiological effect

when a drug is swallowed, it takes time for it to reach the __

therapeutic dose

amount needed for desired effect

prescribed on a medication bottle

bloodstream

once in the __, the drug is slowly removed by absorption into tissues or metabolism

ED50

effective dose for 50% of a population

LD50

single dose lethal to 50% of the population

susceptible individuals die at lower doses

resistant individuals require higher doses

ADME

how drugs move through the body (an acronym)

absorption

entry into the bloodstream

first step of how drugs move through the body

distribution

movement to tissues

second step of how drugs move through the body

metabolism

chemical breakdown (in the liver)

third step of how drugs move through the body

excretion

removal from body (sweat and urine)

fourth and final step in how drugs move through the body

oral (swallowing)

mode of ingestion

subject to first pass metabolism

time elapses before the drug enters general circulation

inhalation/smoking

mode of ingestion

rapid absorption, bypasses liver

allows full amount of drug to directly enter circulation

injection

mode of ingestion

immediate entry into bloodstream (a faster high)

snorting

mode of ingestion

absorption through nasal tissues

allows the full amount of drug to directly enter circulation

first pass metabolism

occurs when drugs are swallowed

compounds are absorbed into bloodstream from the digestive tract

compounds are transferred to liver where they go through metabolism

drug and metabolites enter general circulation

metabolism

significant amount of the original ingested compound can be lost to this

first pass metabolism

often decreases the amount of effective drug that enters circulation

tissues

drugs and metabolites in the blood can be absorbed by __

once in the bloodstream, the whole body is fair game

urine

some drugs and metabolites can be filtered into the __

some can also be deposited in the hair

gastric contents

type of post-mortem sample to test for toxins

tests recent ingestion

used for oral swallowing

vitreous humor

type of post-mortem sample used to test for toxins

resistant to decomposition

liquid behind eyeball

also tested to determine diabetic shock because it shows the glucose levels

qualitative analysis

toxicology involves __ __ (what is ingested substance)

screening tests useful

confirmatory tests provide definitive identification

multiple characteristics used for identification

quantitative analysis

toxicology involved __ __ (how much was taken)

often causes involve more than one ingested substance

findings used to determine how ingested substances played a role in the death

Marsh test

early test example for arsenic

developed to test tissues for arsenic in 1836

produces steam when arsenic is present; samples used were bile and stomach fluid

qualitative test, not quantitative thoguh

mass spectrometry

primary methods for toxicology identification involve __ __ (MS)

instrumentation is complex and expensive

works in stages

mass spectrometry

first module of __ __ separates components by chromatography

ex: separates meth from cocaine from alcohol

mass spectrometry

second module of __ __ fragments compounds into characteristic fragments analyzed by __ __ (MS)

tells how much of a drug there is

known standards are used for comparison to identify compounds

poison

least common mechanism in overdoses

poison

can be accidental, intentional, or homicidal — most are accidental

many common household items on the list

drug overdoses have become one of the most common versions of this

opiates

derived from opium poppy

examples: morphine, heroin, codeine

opioids

synthetic compounds

examples: fentanyl, oxycodone

typically prescribed after procedures

man made opiates

carfentanil

this drug is ~100x as potent as morphine

demonstrates drugs are getting more powerful and being laced

narcan

only works on opiates and opioids not other toxic compounds like xylazine

homicidal poisoning

relatively rare today because most are ruled undetermined and are hard to prove

historically common (arsenic, plants)

modern tech makes detection likely

time delay between administration and death is key

Anna Delaney

only forensic anthropologist in NJ

forensic anthropologist

when skeletal remains are found, investigators contact a __ __

physical anthropology

the study of human biological and physiological characteristics and their evolution

forensic anthropology

application of the theory and methods of anthropology to forensic problems

importance

when skeletonized remains are found it is important to determine forensic __ because remains might be found on an old battlefield or it could be a clandestine grave site

human osteology and odontology

the study of bones and teeth (the longest lasting parts of the body because they are most resistant to decomposition)

forensic taphonomy

the study of the process that causes changes to occur in human remains after death

example: the environment in which the body was found

forensic archaeology

the application of archaeological methods to the recovery of forensically relevant human remains

ossification centers

where bone growth occurs

identification of these help determine age of the remains

206

how many bones are in an adult human body

start with as many as 405 when baby

epiphysis

end of the long bones

metaphysis

where the ossification centers are

where the epiphysis and diaphysis meet on a long bone

diaphysis

part of long bone

the shaft of the bone

recovering remains

step by step process for __ __

1. superimpose a grid

2. photograph and document before work

3. examine for insects and plants

4. remains removed gradually, recording position

5. screening area

6. staging area

ground penetrating radar (GPR)

a type of radar that can be used to visualize and find objects buried in soil

taphonomic context

refers to the immediate environmental and surroundings where a body is found

a complete evaluation of the context is a critical part of the scene processing

decomposition

environmental conditions such as temperature, moisture, and humidity all influence the rate of __ of a body

anthropologist

typically at the morgue (though sometimes on scene) a __ will assess

the stage of decomposition, the amount of scattering, evidence of scavenger chewing, drying and bleaching by the weather and sun, and other damages to bones such as bone cancer or healed and unhealed fractures

biological profile

a collection of data from skeletal remains such as size, shape, estimation of stature, and unique features of bones

cartilage

skeleton forms by growth of ossification centers which replace __

estimate age

to __ __ of skeletal remains, you must understand the development of the skeleton at each stage of life, beginning with the fetus

clavicle and sternum

last two bones to fuse together

occurs around age 25

405

newborn has about __ ossification centers

females

bone development occurs quicker for __

deciduous dentition

20 teeth

2.1.2 (2 incisors, 1 canine, 2 premolars in each grid)

permanent dentition

32 teeth

2.1.2.3 (2 incisors, 1 canine, 2 premolars, 3 molars in each grid)

6 months

age when deciduous teeth erupt and form

6 years

age when deciduous teeth are lost and permanent teeth erupt

18 years

age when third molars/wisdom teeth emerge in about 70% of the population

tooth development

the patterns of __ __ differ slightly by sex and population (just like bone) but are good standards to use for estimating age

bone density

this peaks in mid 20s, remains high in 30s, and begins to decline in the 40s

females experience decline during menopause, but level off after age 55

adult males over 40 experience a gradual decline

females

progress quicker with regards to bone health but degenerate much slower

osteoporosis

severe bine density loss

more common in females and certain populations

cortical bone

outer layer of the bone

trabecular bone

inside of the bone including the blood supply (spongy bone)

bone density

__ __ depends on

age, hormonal status, weight bearing exercise, and nutrition (specifically calcium, magnesium, and vitamin D, and iron)

osteoarthritic lipping

commonly viewed in 55+ communities

also seen in young populations that have rough lifestyle habits (cross fit or gymnastics)

result of bone rubbing on bone in ball and socket joints

pubic symphysis

one of the most reliable indicators of adult age

the area on the pelvis where the right and left halves join in the front of the body across two surfaces (or faces)

with age, these surfaces change from billowed to more flattened and rimmed

sexual dimorphism

differences in size and shape between sexes

males are generally larger and taller on average

males

have more muscles and working those muscles increases the size of bones leading to them being larger on average

puberty

at __, skeletal morphology between sexes differ more

prior to this, anthropologists cannot appreciate many differences (low accuracy rate)

after this, differences between sexes increase (accuracy rate over 90% in sex attribution)

skull and pelvis

most sexually dimorphic areas of the skeleton

the accuracy of determining sex without these bones is very low

sciatic notch

a portion of the pelvis useful in determining the biological sex of an individual

larger in females because of of wider birth canal for birth

subpubic angle

the portion of the pelvis useful in determining the biological sex of an individual

~90^o in males and ~120^o in females

males

generally, __ tend to exhibit

larger weight bearing joint surfaces , more accentuated areas of muscle attachment, large diameters of long bones, and greater stature

long bones

stature estimation if estimated by taking measurements of the __ __

examples: femur, humerus, and tibia

only provide a range, not an exact stature

entomology

the study of insects

entomology

forensic __ is well known for its value in estimating times of death after the 48 hour mark

forensic entomology

__ __ can also aid in revealing other factors such as

whether body has been moved after death, wound sites, and if the victim has been poisoned or drugged

minimum

forensic entomology estimates the __ elapsed time since death, which is not the same thing as the PMI

PMI

range that indicates the least and most time that could have passed since death occurred

forensic entomology is at the lower end range when estimated

puparial

a stage in the life cycle of an insect that follows the larval stage

predictable development of larval Diptera (primarily flies)

time range: few hours to several weeks

successional colonization

the process by which a body is colonized by a series of insects spaced out over time

camon beetles, rove beetles — blowflies swarm first, more variety of insects indicates the body has been decomposing for longer period of time

time ranges: weeks after death until bones dry

temperature

insects are cold blooded meaning they are __ dependent

in hotter climates there is more insect activity

in colder areas there is less insect activity

orifice

human skin is too tough for insects so they will naturally take the path of least resistance and feed on wounds or a natural __ like the nose with a mucosal layer

insects

in homicide cases, if there are wounds even small needle marks, the __ will colonize those areas

blowflies

the first insects attracted to remains

“Diptera”

feed primarily on sugary sources and protein

body is suitable site for females to lay eggs