other biological fluids, tissues, and touch dna Flashcards
bite marks and saliva
comparison of bite mark and suspect’s dentition photographs
plane parallel using a L scale
perimortem/ potmortem tend to be better defined
collect sample (swab) for dna anlaysis
bite mark analysis is considered subjective to the person evaluating the evidence
innocence project states there is no real scientific support of research into the accuracy or reliability of bite mark evidence
many convictions from bite mark evidence have happened in the past and now the suspects are being exonerated through IP
other GI tract evidence
stomach contents
vomitus
both not a good source for dna
stomach contents
gross and microscopic examination
set time of death
provides investigative leads
where did the deceased last eat
vomitus
microscopic and biochemical analysis
pepsin-proteolytic enzyme
HCl secretion of the stomach has pH 0.8
sexual fetishes
intestine length is very very long
human fecal matter
avg 60-250 grams feces are eliminated dialy
feces produced from an avg diet is 75 % water and 25% solid material
30% of solid material is bacteria
estimated 10^11 bacteria cells per gram of feces in sigmoid colon
identify fecal matter by
odor-skatole and indole
color stercobilin(brown) (bilirubin metabolite (orange and yellow))
one end product of heme catabolism, breaks down hemoglobin
bilirubin
orange-yellow pigment formed in the liver by the breakdown of hemoglobin and excreted in bile
present in fecal material
animal cells - meat
plant cells
epithelial cells
bacteria
identification of fecal matter
fluorescent test
urobilin/urobilinogen
microscopic analysis bacteria, dietary plant material, GI epithelial cells, parasites, etc
green bean dog bones
digested green beans only could be present in fecal material
biochemical analysis
pancreatic amylase, IgA, alkaline phosphatase
Gastrointestinal GI tract
epithelium is renewed every 2-6 days
GI organs have diff turnover rates
estimated 17 billion cells are shed daily from the human small intestine
columnar cell
responsible for absorption of metabolites
goblet cell
protection and lubrication of intestinal lining
both types of cells are epithelial
cuboidal epithelial cells
DNA analysis
analytical difficulties with human feces
degradation of human cells and dna
bacteria
innate PCR inhibitory substances
will block per amplification
plant polysaccharides
bile acids, salts , cholesterol
solution
qiagen qiamp stool mini kit
preferential lysis of human cells over bacterial cells using room temp digest
proprietary organic metric
inhibit ex bugger which is specially formulated to separate inhibitory substances from dna
isolation of dna achieved by a silica Gell membrane and spin column
urine identification
locating stain
use ALS, will fluoresce
microscopic analysis of urinary sediment
three components of urine
urea, creatine, Tamm-horsfall urinary glycoprotein
urea
largest constituent of urine
microscopic crystal test
color test, DMAC (o-dimethylamino cinnamaldehyde)
non-specific, cross reacts with sweat
GC-MS
creatine
color test
GCMS
Abacus diagnostics uritrace test, reacts with creatine
Tamm-horsfall urinary glycoprotein
most abundant urinary protein in mammals
immunological assays: RIA, ELISA, CIE, Ouchterlony
CIE (crossover immunoelectrophoresis)
RSID
urinary sediment
kidney - cuboidal cells
bladder - transitional cells, often binucleated
urethra - columnar cells, squamous at glans pens
vaginal contamination - squamous cells
spermatozoa
urniary casts - result of solidification of material (protein) in the lumen of the kidney tubules, specifically the nephron, and eliminated via the urine
individualization of urine
very variable
like the amount of saliva between people and days
skin
most important role is to protect the body from the environment
3 main layers
epidermis
dermis
subcutaneous fat
human skin
glabrous - thick skin
palms of hand, soles of feet
hair free
still has pores and sebaceous glands
thicker than hair skin
non-glabrous - normal skin
90% of body
contains hair follicles that produce hair
epidermis
5 sublayers, continuously rebuild skin
stratum corneum
a layer of dead flattened enucleated cells filled with the protein keratin
stratum lucidum
the nuclei and other cell organelles disintegrate as the cell dies
stratum granulosum
keratinocytes migrating from underlying stratum spinous
transfer of melanin granules to cells
stratum spinous
keratinocytes (mature basal cells)
produce keratin
contains immune cells called langerhan’s cell
stratum basale
deepest layer of epidermis
contains continually dividing basal cells
melanocytes (color) found between basal cells
losing nucleus, gaining keratin from basale to corneum
epidermis
30-45 days time it takes for basal cells to mature and migrate to top of the epidermis
avascular
cells at surface are continuously shed
millions of cells lost daily
over 8 pounds shed yearly
contributes to household dust
dermis
true skin
highly vascular
hair follicles
sweat and sebaceous glands
collagen fibers for elasticity
dermal papillae
projections of dermis into overlying epidermis
brings dna closer to surface, glands do the same
sebaceous - oily, stinky
swear - more watery
sweat glands
ducts of sweat glands course through the inter papillary pegs to the surface of the skin
inter papillary pegs
wehre epidermis is much thinner
brings dna closer to surface
dna within seat
epidermis also sheds dna with sweat
touch dna
located exchange principle
every contact leaves a trace
generally understood as with contact between two items, there will be an exchange
oily hair dna from oil from sebaceous glands
touching face eyes nose a lot
more dna on hands
if the top layer of skin doesn’t have nuclei how can we find touch dna
nucleated cells, dna are shed through sweat and sebaceous glands
there could be short pieces of free dna present that in totality create a profile
from process of shedding
dna could be transferred from other areas of the body
like from saliva
dermal ridges
dots on photo are sebaceous or sweat glands
could potentially shed dna
skin slippage
epidermal layer sloughs off
part of decomposition
needs to be rehydrated then worn like a glove
rangers cleavage lines
orientation of collagen bundles in the dermis
can distort skin defects
same knife made all wounds
looks diff due to cleave line distortions
human hair
elongated karatiNized structures derived from an invagination of the epidermal epithelium
hair follicle
hair bulb is the terminal end
dermal papilla
contains a capillary network that sustains the hair
lost reproducing cells, root
massive cell growth therefore massive amount of nuclear dna
epidermal cells that cover the dermal papilla form the hair root
follicles are in the dermis
dna in hair
3 phases of hair growth
anlagen, root alive, growing phase, root when pulled out
catagen - root dying, resting phase
telogen, root dead, won’t always have dermal papillae and no dna
hair that falls out naturally
hair cells enucleated therefore no nuclear dna in shaft
rich in mitochondrial dna in shaft
plucked hairs have root - ndna
pubic hair combings
looking for foreign hairs
usually more souces of dna outside of this
no longer done
nails
plates of keratinized epithelial cells
corresponds to the stratum corneum of skin
rests on nail bed which only contains the stratum basal and stratum spinous
this epithelium allows for view of the color of the blood in the dermal vessel
vascular network, press it and it turns white
nail swabs
nail scrapings
nail clippings
the skin attached to the nail clippings is rich in dna
be careful because It could overwhelm the profile
be discriminate of where you are sampling from
clippings can visualize where you want to sample
bone
organic matrix
50% by volume
25% by weight
90% collagen type 1
mineral component
calcium phosphate
calcium carbonate
hydroxyapatite
metric and minerals work against each other for dna
types of cells in bone
osteocyte mature bone cell
osteoblast
forms bone matrix
osteogenic cell
stem cell
osteoclasts
reabsorbs bone
haversion system with canals
everything else is mineral calcium
dense and mineralized therefore cells with dna are very hard to get to
bone other tissues
bone marrow
very good for dna
endosteum
periosteum
more of less nucleated
nerves
blood vessels
cartilage not vascularized
dna extraction from bone
decalcification EDTA
need fine bone powder
tissue grinders
freezer mill
promega dna extraction kit
dna extraction without pulverization
pressure cycling tech
nuclear dna from bone is difficult to obtain but important
bone lasts loners, tissues decompose
often teeth pulled
mass disasters, skeletal remains
gun
firearms render safe
dna
look for potential fingerprints so you don’t swab there
look, oblique lights, microscope
positive for prints - latent prints
look for blood, swab trigger, slide grips, handle
4 swabs, last is overall of everywhere you didn’t swab
stained sweatshirt in closet
2 connections
victim with blood
suspect with sweater
wearer’s dna in back neck, armpits cuffs
if taken off suspect when arrested, wearer’s dna is not needed
fecal
can give + AP
microscope
if no sperm
P30
if none then it is not sperm
screen for blood as well
rape with foreign object
epithelial cells
distinguish vag or oral
blooddrops
how many bleeders
if 1 then one sample
if multiple then analyze more
