Models Of Disease Flashcards

(59 cards)

1
Q

What does in vivo mean?

A

Cells growing in their normal biological context
Inside the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does ex vivo mean?

A

From the body but now outside the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does explantation mean?

A

Tissue growing outside the body in culture
Outside normal biological context

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does in vitro mean?

A

Latin for in the glass
Cells growing in culture outside the normal biological context

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a tissue culture?

A

The growth of cells from a tissue from a multicellular organism in vitro

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are primary cells?

A

Cells isolated from a donor organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are cells maintained and grown in culture?

A

Given essential nutrients
Correct physio-chemical environment
Grown in substrate
Given growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the necessary nutrients for cell growth in a culture?

A

Amino acids
Carbohydrates
Vitamins
Minerals
Hormones
Gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the physio-chemical environment refer to?

A

pH
Osmotic pressure
Temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the difference between primary cells and immortalised cells?

A

Primary have a limited life span and will not proliferate indefinitely
Immortalised cells can proliferate indefinitely through random mutation or deliberate modification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is senescence?

A

Undergo according to their Hayflick limit
The mean number of doubling times before division ceases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is cell confluency?

A

The proportion of the culture dish or flask covered by adherent cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Different cell confluencies

A

10% - ideal for planting/seeding
30% - good for transfection
50% - will need to split soon, not much more room left to grow
90% - cells touching, good barrier function tests and western blot to maximise protein harvest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an apoptotic cell?

A

A type of cell death in which a series of molecular steps in a cell lead to it death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the advantages to in vitro studies?

A

Relatively cheap and easy
High level of control
Test drugs easily and quickly
Potential to investigate disease models and cell interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a simple in vitro cell culture model?

A

2-D monolayers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a complex in vitro cell culture method?

A

3-D gel cultures and co-cultures
Transwell systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the limitations of tissue culture?

A

Potential for cross species contamination
Introduction of viruses/prions
Animals have homeostasis - cultures don’t
Animals vary in genetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the limitation of in vitro culture?

A

Loss of specialised extracellular matrix
Loss of paracrine stimulation and endocrine factors
Loss of contact mediated stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the outcomes of induced pluripotent stem cells?

A

Reduce risk of immune rejection
Sidestep ethical concerns of using embryos
Opportunity to put right problem at the genetic level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Limitations of induced pluripotent stem cells

A

Are they mutation free?
Are they potentially cancerous?
Can they really be grafted back into a patient?
How long will they survive in vivo?
Will they actually solve the problem?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is personalised medicine?

A

Drug testing on the individuals genome
Investigating the genetic origins of the disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are in vivo studies?

A

Any surgical procedure, imaging or behavioural experiment done on live animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do you induce a disease in in vivo experiments?

A

By surgery - partial pancreatectomy to induce diabetes
Chemicals and toxins - carcinogens
Dietary manipulation
Implantation of cells

25
How to begin an in vivo experiment
Breeding of and experimentation of naturally occurring genetic diseases Genetic manipulation to change expression of the gene Breeding of transgenic animals
26
In vivo experimentation can include the injection of what substances?
Saline Drugs Cells
27
What are some arguments for the use of animal experimentation?
Can replicate complex diseases Closer to human physiology than cell cultures Maintains cell to cell interactions Can prove a concept better than in vitro It is really healing to cure and treat cancer
28
Give some arguments against the use of animal experimentation
No animal experiment can absolutely predict what will happen in humans We are not more important than animals what gives us the right to use them
29
What is the animal experimentation legislation?
Cruelty to animals act 1876 - enforced a licensing and inspection system for vivisection Protection of animals act 1911 - largely repealed - regulation regarding animal cruelty Animals (scientific procedures) act 1986 - act of parliament which regulates the use of animals used for research in the UK - all living vertebrates except humans
30
What does ASPA do?
Define legitimate purposes for animal use in experiments Provides inspection of facilities and procedures Ensures humane standards of husbandry are care Ensures public accountability
31
At what point does ASPA take effect
From two thirds of the way through the gestation/incubation
32
When is an animal experimentation no longer regulated by ASPA?
The circulation has stopped permanently or the brain is completely destroyed
33
What are the 3Rs of ASPA?
Replace Reduce Refine
34
What are the three points of the first R - replace
Experimenting on cell cultures instead of whole animals Use computer models, humans, population studies instead Try non-traditional methodologies
35
What are the three point for the second R - reduce?
Improving experimental technique Improving techniques of data analysis Sharing information and tissues with other researchers
36
What are the three points for the third R - refine?
Better medical care and living conditions Minimise distress Minimise pain
37
What is constitutive or conventional KO?
Where every cell in the body lacks functional expression of a gene of interest at the protein level
38
What is CrispR-Cas9?
It was designed to find and cut a unique gene sequence
39
When is CrispR-Cas9 used?
Carried out on an egg or embryonic stem cell to delete or insert DNA one one allele
40
What does CrispR-Cas9 result in?
Resultant embryo has 1 dysfunctional gene Implant embryo and grow until birth Identify successful KOs
41
What are the steps to breeding KO animals?
Breed (-,+) with (-,+) to get (+,+) and (-,-) for experimentation Keep some (-,+) Genotype each pup Breed (-,-) with (-,-) so all offspring are (-,-) Don’t need to genotype every pup Wildtypes needed for control
42
How do you identify protein loss?
Immunohistochemistry (IHC) Western blot In situ hybridisation
43
How does immunohistochemistry and western blot work?
Depend on antibodies recognising a site on the protein after the point of KO but not all proteins have selective antibodies targeting these regions
44
How does in situ hybridisation work?
Recognises mRNA Designed to find the mutation Expensive and more difficult to do but also more accurate
45
Which are the easiest KOs to genetically identify?
Transgenders with large insertions/deletions Easily ID using PCR of genomic DNA
46
Transgenic animals as models of disease
Technological advances have increased our ability to create models of human disease Whole body - conventional knockout Inducible whole body knockout Tissue specific knockout Gene reporter Knock-ins
47
What are the advantages of whole body knockouts?
Relatively easy Fairly cheap Easy to genotype using PCR Every cell is affected Easy to determine main functions of gene Good for in vivo work Simple controls
48
What are the disadvantages to whole body knockouts?
Can’t say the effect in solely due to loss of one action Loss of expression can be compensated for by other genes CrispR site may not be specific to the gene of interest 15% of KOs are embryonically lethal
49
How to avoid embryonic lethality in KO therapy
Gene of interest is floxed by inserting LoxP restriction sites on either side of gene of interest in the embryo Grow into the animal but gene is KOed when you tell it to be
50
How to produce an inducible knockout?
Breed CRE animal with floxed animal to get Cre-LoxP
51
What are the advantages of inducible KO?
Avoids embryonic lethality Comparative study of before and after KO in the same animal Very flexible Mimic pathology of late onset Less problems with compensatory expression
52
What are the disadvantages of inducible KO?
Differential penetration of trigger compound into tissues - need to prove changes at protein level Adding the LoxP site risks modification or disruption of splicing regulation Tetracycline inducible systems may be leaky Proteins may be promiscuous
53
What are the advantages of tissue specific KO?
Study gene function in one specific organ/tissue/cell Mimic pathologies caused by gene activation Create tissue specific phenotype for multifunction protein Investigate signally pathways in certain cell types
54
What are the disadvantages to tissue specific KO?
No gene is really specific to one cell type Added expense Proving cell specific KO is difficult in tissues of mixed cell types Embryonic lethality
55
What are reporter genes?
Identify where proteins are expressed Identify cells/embryos which possess the trans gene
56
Give an example of what a reporter gene could be
A gene which provides resistance to antibiotics so KOed embryos could be positively selected with high does antibiotic
57
What are the advantages of knock-in models of disease?
Can prove role of mutation in diseases Can investigate human diseases in animals Can add back in a deleted gene and prove no compensation
58
What are the disadvantages of knock-in models of disease?
Difficult to make accurately May need sequencing to prove successful mutation
59
What are the four types of transgenic models?
Conventional Inducible Tissue specific Knock-in