Models of disease

Question 1

cancer

Answer 1

3-6 mutations to epithelial cells -> increase proliferation and decreased cell death.
escape immune system, grow blood vessels, move and metastasise

Question 2

in vitro

Answer 2

cell culture

Question 3

in vivo

Answer 3

animals

Question 4

in vitro cancer model

Answer 4

grow cell lines from humans/animals (grow indefinitely)

use nutrients and serum from cow foetuses

Question 5

Chou-Talalay method

Answer 5

statistic analysis to see how it interacts with older drugs
additive - 1
synergistic - less than one = more than additive effects
antagonistic - over one

Question 6

cytotoxicity study

Answer 6

add drug and wait 4 days to assay IC50

Question 7

mechanism of action (cancer)

Answer 7

how kills cells = stain with fluorescence to see change in shape

Question 8

problems with cell lines

Answer 8

not physiologically accurate

doesn’t take into account other cell types involved in cancer (blood cells, fibroblasts, stroma, etc) = microenvironment

Question 9

co-culture

Answer 9

direct mixing of cells (use fluorescence to differentiate)

Boyden Chambers = liquid environment and migration

Question 10

3D spheroids

Answer 10

3D deformable structure with scaffold of extracellular matrix
difference in proliferation, metabolism and matrix in layers (necrotic pit)

Question 11

in vivo cancer models

Answer 11

mice can model primary and metastatic tumours
consider tumour type, genetics, location, microenvironment, vasculature, immune system
predict ADME, efficacy, resistance, toxicology
tropic (subcutaneous) or naturally (genetics)

Question 12

nude mice

Answer 12

inbred, inject human tumour cells (xenografts) subcutaneously
lack thymus (no T cells, no immune system, SCID)
can measure tumour and easily extract
however, different development and incomplete stroma

Question 13

syngeneic mouse model

Answer 13

normal mouse with special tumour
same genetics from mouse strain
no immune response

Question 14

orthotopic model

Answer 14

surgery into organ

better representation of microenvironment and development

Question 15

humanised mouse model

Answer 15

immune cells from human (T cells, NK cells, Ag primed DCs, HSC) into mouse with no immune system
PDX = patient derived xenograft

Question 16

conditional models

Answer 16

genetic disease model
K-ras mutation = lung cancer
mice die early on
can add removable transcription termination element (removed by virus)

Question 17

studying tumours

Answer 17

growth rate and tumour size/weight
remove tumour and graph against time
look for metastases - fluorescence markers or staining

Question 18

neurology animal models

Answer 18

produce neuropathy or similar symptoms

quality = valid representation of human disorder (prove and measure) and reproducible

Question 19

behavioural assay

Answer 19

normally on a scale (observer or patient)

final test done via this (not cell culture or computer)

Question 20

anxiety disorders

Answer 20

PTSD, GAD, panic disorder, phobias, OCD
developed over time and has triggers
PTSD and GAD easier to model

Question 21

anxiety drugs

Answer 21

benzodiazepines, zopiclone, triazolam, antidepressants, beta blocker

Question 22

elevator plus maze

Answer 22

measures acute anxiety
most common
rats don’t like open space
two closed arms and two open arms = measure time in each

Question 23

validate method

Answer 23

use control
short term vs long term 
optimal conditions (eg no ambient noise)
variable results = not statistically significant

Question 24

dose translation equations

Answer 24

GD = AD x animal Km/human Km

Question 25

ethics in vivo

Answer 25

is there significant stress (eg induce depression)

validity and reliability must be determined