Lecture Content

Question 1

An article that describes and interprets an individual case, often written in the form of a detailed story

Answer 1

Case study

Question 2

When are case studies most appropriate?

Answer 2

Unique cases that cannot be explained by known diseases or syndromes

Cases that show unexpected events/ may yield new or useful information

Question 3

Considered lowest level of evidence but first line where new issues/ evidence arises

Answer 3

Case study

Question 4

What are he advantages of a case study?

Answer 4

Can help identification of new trends/ diseases
Can help detect a new drug side effects and potential uses
A way of sharing lessons learned (educational)
Identifies rare manifestations of a disease

Question 5

What are the disadvantages of a case study?

Answer 5

Causes may not be generalisable
Not based on systematic studies
Causes or associations may have other explanations

Question 6

A study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease (control)
It looks retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between risk factor and disease.

Answer 6

Case control study

Question 7

Is a case control study observational or interventional?

Answer 7

Observational

Question 8

What is the goal of a case control study?

Answer 8

Determine effect of exposure to risk factor in both groups

Question 9

What are the advantages of a case control study?

Answer 9

Good for studying rare conditions/ diseases
Less time required to conduct study as disease has already occurred
Allows you to look at multiple risk factors simultaneously

Question 10

What are the disadvantages of a case control study?

Answer 10

More problems with data quality as rely on patient memory (recall bias)
Not good for evaluating diagnostic tests
Difficult to find suitable control group

Question 11

One or more samples, known as cohorts are followed prospectively and evaluations are made with respect to disease or outcome to determine which participants exposure to which risk factors are associated

Answer 11

Cohort study

Question 12

What are the advantages of a cohort study?

Answer 12

Subjects in cohorts can be matched limiting confounding variables
Standardisation of criteria/ outcome possible
Easier and cheaper than RCT

Question 13

What are the disadvantages of a cohort study?

Answer 13

Cohorts difficult to identify due to confounding variables
No randomisation - imbalance in patient characteristics could exist
Blinding is difficult
Outcome of interest could take time to occur

Question 14

Randomly assigns participants into experimental and control groups. Only expected difference between control and experimental group = outcome variable being studied (in theory)

Answer 14

Randomised control trial (RCT)

Question 15

What are the advantages of a randomised control trial?

Answer 15

Good randomisation removes population bias
Easier to blind than observational studies
Results can be statistically analysed
Populations of participating individuals can be clearly identified

Question 16

What are the disadvantages of a randomised control trial?

Answer 16

Expensive- time and money
Volunteer biases- population that participate may not be representative of the whole population
Doesn’t give causation
Can’t follow up with treatment

Question 17

What are Koch’s postulates designed to establish?

Answer 17

Causative relationship between microbe and disease

Question 18

Name koch’s postulates

Answer 18

1. ) the microorganism must be found in abundance in all organisms suffering from the disease, but not in healthy organisms
2. ) the microorganism must be isolated from a disease organism and grown in pure culture
3. ) the cultured microorganism should cause disease when introduced into healthy organism
4. ) the microorganism must be reisolated from the inoculated diseased experimental host and identified as being identical to the original specific causative agent

Question 19

Define paradigm shift

Answer 19

A fundamental change in the basic concepts and experimental practices of a scientific discipline

Evidence builds up that contradicts the prevailing theory and the theory undergoes crisis

A new paradigm is established, and scientists work ‘normally’ within those paradigms

Question 20

What does qPCR tell you?

Answer 20

How much specific mRNA there will be in your sample

Question 21

What does the Ct measure?

Answer 21

Cycle number at which fluorescence starts increasing

Question 22

What is mRNA converted into in qPCR, and via what enzyme?

Answer 22

mRNA –> cDNA via reverse transcriptase

Question 23

What does a lower Ct measure indicate?

Answer 23

Lower Ct = signal appears quicker = more mRNA present in the sample

Question 24

How do you calculate the fold increase in expression in qPCR?

Answer 24

2- delta delta Ct

Question 25

What is the purpose of PCR?

Answer 25

Making many copies of a piece of DNA

Can be used to detect presence or absence of viral DNA

Question 26

What is the rough protocol of a PCR cycle?

Answer 26

Heat to 96 (denature)
Cool to 60 (primers anneal)
Heat to 73 (taq polymerase synthesises new DNA)
Repeat