Clinical sciences Flashcards

1
Q

What are funnel plots used for?

A

Used to demonstrate publication bias in meta analysases

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

How do you interpret funnel plots?

A

Symmetrical, inverted funnel shape - pub bias unlikely

asymmetrical funnel - relationship present between treatment effect and study size –> publication bias or systematic difference between smaller and larger studies (small study effects)

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

thin acending loop of henle - what can and cant get through?

A

Impermeable to water

Highly permeable to Na and Cl

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

early-onset breast cancer, sarcoma and leukaemia

Condition? gene?

A

Li-Fraumeni syndrome - p53 mutation

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

What is p53 gene for?

A

Crucial role in cell cycle - prevents entery into S phase until DNA has been checked and repaired

May also regulate apoptosis

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

Which pneumocytes secrete surfactant?

A

Pneumocyte type 2 - can differentiate into type 1 during lung damage

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

Difference between cranial and nephrogenic DI

A

Cranial - deficiency of ADH

Nephrogenic - insensitivity to ADH

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

Where does ADH act and what does it do?

A

ADH promotes water reabsorption via insertion of aquaporin 2 channels in collect ducts

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

What triggers release of ADH?

A

extracellular fluid osmolality increase
volume decrease
pressure decrease
angiotensin II

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

What reduces secretion of ADH?

A

extracellular fluid osmolality decrease
volume increase
temperature decrease

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

C1 inhibitor (C1-INH) protein deficiency - consequence?

A

causes hereditary angioedema
C1-INH is a multifunctional serine protease inhibitor

probable mechanism is uncontrolled release of bradykinin resulting in oedema of tissues

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

C1q, C1rs, C2, C4 deficiency (classical pathway components) - consequence?

A

predisposes to immune complex disease
e.g. SLE, Henoch-Schonlein Purpura

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

C3 deficiency - consequence?

A

causes recurrent bacterial infections

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

C5 deficiency - consequence?

A

predisposes to Leiner disease

recurrent diarrhoea, wasting and seborrhoeic dermatitis

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

C5-9 deficiency - consequence?

A

encodes the membrane attack complex (MAC)

particularly prone to Neisseria meningitidis infection

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

What diseases is endothelin involved in?

A

primary pulmonary hypertension (endothelin antagonists are now used),

cardiac failure,

hepatorenal syndrome

and Raynaud’s.

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

Calculation of absolute risk reduction?

A

Absolute risk reduction = (Control event rate) - (Experimental event rate)

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

Where in nephron does majority of glucose reabsorption occur?

A

Proximal convoluted tubule

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

What is the genetic phenomenon of anticipation? Which disorders are more likley to experience this?

A

earlier onset in successive generations

Particularly present in trinucleotide repeat disorders

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

Most common cause of Down Syndrome (genetically)

A

Nondisjunction

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

prenatal tests showing low circulating levels of pregnancy-associated plasma protein-A (PAPP-A) and an abnormal nuchal translucency screening test

Diagnosis?

A

Downs syndrome

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

Examples of mitochondrially inherited disease?

A

Leber’s optic atrophy
symptoms typically develop at around the age of 30 years
central scotoma → loss of colour vision → rapid onset of significant visual impairment

MELAS syndrome: mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes

MERRF syndrome: myoclonus epilepsy with ragged-red fibres

Kearns-Sayre syndrome: onset in patients < 20 years old, external ophthalmoplegia, retinitis pigmentosa. Ptosis may be seen

sensorineural hearing loss

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

Children of fathers with mitochondrialy inherited disease?

A

For a man with mitochondrial disease, none of his children will inherit the condition

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

What is Gaucher’s disease? How does it present?

A

Gaucher’s disease is an autosomal recessive disease and it is the most common lipid storage disorder

Leads to accumulation of glucocerebrosidase in brain, liver and spleen

Present with hepatosplenomegaly and aseptic necrosis of femur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which metabolic disorder causes:
Developmental delay
Cherry red spot on macula
+- hepatosplenomegaly

A

If no hepatosplenomegaly - Tay-Sachs disease

If hepatospenomegaly - Niemann-Pick disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Most common cardiac and renal abnormalities in Turner’s?

A

Cardiac - Biscuspid aortic valve (15%), coarctation of aorta (5-10%)

Increased risk of aortic dilatation and dissection

Renal - horseshoe kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does specificity and sensitivity mean?

A

Specificity - Proportion of patients without the condition who have a negative test result
TN / (TN + FP)

Sensitivity - Proportion of patients with the condition who have a positive test result
Sensitivity = TP / (TP + FN )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is lead time bias?

A

Occurs when two tests for a disease are compared, the new test diagnoses the disease earlier, but there is no effect on the outcome of the disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

HLA DR3 is associated with which conditions?

A

dermatitis herpetiformis
Sjogren’s syndrome
primary biliary cirrhosis

T1DM (More strongly associated with DR4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How to calculate NTT?

A

NNT = 1 / Absolute Risk Reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Short stature + primary amenorrhoea

Diagnosis?

A

Turners syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the parametric tests and non-parametric tests? When to use which?

A

Parametric - normally distributed data

Parametric tests:
- Students t test (paired v unpaired - single group of patients if paired)
- Pearsons product moment coefficient - correlated

Non-parametric tests
- Mann Whitney U test
- Wilcoxon signed rank test
- Chi-squared test
- Spearman, Kendall rank - correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which statistical test to use when:
comparing ordinal, interval, or ratio scales of unpaired data

A

Mann-Whitney U

Nominal = categorical = qualitative
No sense of order
E.g ; sex , color
Frequency/proportion ; percentages

Ordinal
Rank , satisfaction , fanciness
Frequency/proportion ; percentages

Interval / ratio = scale = quantitative = parametric
Number of costumers
Weight
Age
Size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Which statistical test to use when:

comparing two sets of observations on a single sample, e.g. a ‘before’ and ‘after’ test on the same population following an intervention

A

Wilcoxon signed rank

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which statistical test to use when:
Comparing proportions or percentages e.g. compares the percentage of patients who improved following two different interventions

A

Chi-squared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Karyotype in Turners?

A

45 XO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Which dermatological condition is associated with Coeliac - how does this look? Which HLA is this associated with?

A

Dermatitis herpetiformis - intensely itchy, papulovesicular, blistering rash, similar to that seen in herpes infection

Associated with HLA DR3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How can you work out variance if you know SD?

A

SD^2 = variance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Which studies are most affected by recall bias?

A

Case control studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Multiple sarcomas at young age - what genetic condition and what gene + its role?

A

Li-Fraumeni syndrome

Mutation in p53 (tumour suppressor gene 17p) - holds cell cycle at G1/S phase checkpoint allowing for detection + repair of DNA damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

When is the mean, mode and median the same?

A

in a normal distribution of data-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Which chromosome encodes for HLA antigens?

A

Chromosome 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why can sepsis lead to Hypotension?

A

Sepsis -> release of IL1 which causes vasodilation and hence hypotension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What do the different subunits of troponin bind to?

A

troponin C: binds to calcium ions

troponin T: binds to tropomyosin, forming a troponin-tropomyosin complex

troponin I: binds to actin to hold the troponin-tropomyosin complex in place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the purpose of secondary messenger system? what can trigger the cGMP system?

A

Secondary messengers - allow for amplification of external stimulus

ANP and NO act as ligand hormones for cGMP system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What describes the power of a study? how can you calculate it?

A

the probability that a statistically significant difference will be detected / probability of (correctly) rejecting the null hypothesis when it is false / which also means the probability of confirming the alternative hypothesis when the alternative hypothesis is true

Power = 1 - probability of type 2 error (beta)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Inheritance of G6PD?

A

X linked recessive so no male to male transmission

Hence titos son’s can’t have G6PD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Where is phosphate reabsorbed in the nephron?

A

PCT is responsible for phosphate reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the main parts of antibodies and what binds to each part?

A

Fab region: antigen-binding fragment - the region that binds to antigens

Fc region: fragment crystallizable region - the tail region of an antibody that interacts with cell surface receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Reactive arthritis HLA?

A

HLA B27

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is Fabry disease? How is it inherited?

A

X linked recessive - lysosomal storage condition

leads to kidney failure, HF, body pain and skin issues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is a type 2 error in stats?

A

Type II error - the null hypothesis is accepted when it is false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the usual outcome measure in cohort studies?

A

Relative risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What cytokine is involved in development of granulomas?

A

Inf-gamma = used in macrophage activation which leads to the formation of granuloma

may be useful in chronic granulomatous disease and osteopetrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What happens during reverse transcriptase PCR? what is this used for?

A

RNA is converted to DNA

It is used to detect gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

the probability of obtaining a result by chance at least as extreme as the one that was actually observed, assuming that the null hypothesis is true

What does this describe?

A

P value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

how can you calculate standard error of mean?

A

Standard deviation / square root (No. of patients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Difference between type 1 and 2 errors?

A

Type I: the null hypothesis is rejected when it is true (false +ve)

Type II: the null hypothesis is accepted when it is false (false -ve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are some examples of X linked dominant conditions?D

A

Alports

Retts

Vit D resistant rickets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the main action of PCR reactions?

A

DNA amplification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What is incidence?

A

The incidence is the number of new cases per population in a given time period.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is prevalence? point v period?

A

The prevalence is the total number of cases per population at a particular point in time

point prevalence = number of cases in a defined population / number of people in a defined population at the same time

period prevalence = number of identified cases during a specified period of time / total number of people in that population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is the relationship between incidence and prevalence?

A

prevalence = incidence * duration of condition

in chronic diseases the prevalence is much greater than the incidence

in acute diseases the prevalence and incidence are similar. For conditions such as the common cold the incidence may be greater than the prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Early strokes / MIs + proteinuria + typical rash (angiokeratomas)? How does the rash look and what is the condition / inheritances?

A

rash in a bathing-suit distribution - angiokeratomas

X linked recessive deficiency of alpha-galactosidase A -> FABRY DISEASE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

When to use Wilcoxon signed rank test?

A

Non-parametric

compares two sets of observations on a single sample, e.g. a ‘before’ and ‘after’ test on the same population following an intervention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Effect of metanalyses on power and p value v individual studies?

A

Increase power

decreaase p value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Which virus is a RF for oropharnyngeal ca? what else is this a RF for?

A

HPV 16/18

Also for cervical, vulval, anal, penile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Which Ca is increased risk with EBV?

A

Burkitt’s lymphoma
Hodgkin’s lymphoma
Post transplant lymphoma
Nasopharyngeal carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Risk of which ca with Hep B+C?

A

HCC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Human T-lymphotropic virus 1 increased risk of which conditions?

A

Adult T cell leukaemia

Tropical spastic paraparesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

How to calculate NNT? and everything in the calculation?

A

1/(Absolute risk reduction)

Absolute risk reduction = CER-EER or EER-CER

EER = (Number who had particular outcome with the intervention) / (Total number who had the intervention)

CER = (Number who had a particular outcome with the control/ (Total number who had the control)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Homocystinuria - what is the tx?

A

B6 (Pyridoxine) supplementation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are the features of diabetic nephropathy under biopsy?

A

Kimmelstiel-Wilson lesions (odulular hyaline areas develop in the glomuli), nodular glomerulosclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are diseases inherited in a mitochondrial pattern? (5)

A

Leber’s optic atrophy
symptoms typically develop at around the age of 30 years
central scotoma → loss of colour vision → rapid onset of significant visual impairment

MELAS syndrome: mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes

MERRF syndrome: myoclonus epilepsy with ragged-red fibres

Kearns-Sayre syndrome: onset in patients < 20 years old, external ophthalmoplegia, retinitis pigmentosa. Ptosis may be seen

sensorineural hearing loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

ABL is the oncogene for?

A

Chronic myeloid leukaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

c-MYC and n-MYC is the oncogene for?

A

cMYC = Burkitt’s lymphoma

nMYC = Neuroblastoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

BCL2 is the oncogene for?

A

Follicular lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

RET is the oncogene for?

A

Multiple endocrine neoplasia (types II and III)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

RAS is the oncogene for?

A

Many cancers especially pancreatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

erb-B2 is the oncogene for?

A

erb-B2 (HER2/neu) = Breast + ovarian Ca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Which cytokine is responsible for activating macrophages?

A

Interferon-γ

82
Q

Which conditional are generally Autsomally recessive - exceptions?

A

Autosomal recessive conditions are ‘metabolic’

exceptions: inherited ataxias

83
Q

Which conditions are generally autosomally dominant? exceptions?

A

Autosomal dominant conditions are ‘structural’

exceptions: Gilbert’s, hyperlipidaemia type II

84
Q

MoA of homocystinuria?

A

deficiency of cystathionine beta synthase

85
Q

Causes of lens dislocation - upward v downward?

A

Lens dislocation
‘Moon is up and home is down’

Moon = marfanoid and home= homocystinurea

86
Q

Urinalysis and microscopy reveals muddy brown granular casts.

Pathology?

A

Acute tubular necrosis

87
Q

Features of DiGeorge syndrome? What is underlying pathology?

A

CATCH22:
C - Cardiac abnormalities
A - Abnormal facies
T - Thymic aplasia
C - Cleft palate
H - Hypocalcaemia/ hypoparathyroidism
22 - Caused by chromosome 22 deletion

1o immunodeficiency disorder caused by T-cell deficiency and dysfunction - increased risk of viral and fungal infections

88
Q

mitochondrial inheritance
onset < 20-years-old
external ophthalmoplegia
retinitis pigmentosa

What is the disorder?

A

Kearns-Sayre syndrome

‘Cant see yar’

89
Q

Turners features?

A

ABC Clowns

A - primary Amenorrhea
B - absent Barr body
C - Cystic fibrosis

C - Cardiac anomalies (most common - coarctation of aorta)
L - Lymphoedema, low thyroid
O - Ovaries under developed (streak ovaries)
W - Webbed neck
N - Nipples widely placed
S - Short stature, Sensoneural hearing loss, Short 4th metacarpal

90
Q

Cell cycle - what is the resting phase?

A

G0

91
Q

Cell cycle - what phase determines length of cell cycle, what controls this?

A

G1 (Gap1) = under influence of p53

92
Q

What is the shortest phase of the cell cycle?

A

Mitosis (M)

93
Q

Which disease is associated with:

developmental delay and cherry red spot on the macula, without hepatomegaly or splenomegaly

What if hepato / splenomegaly present?

A

Tay-Sachs disease

If megaly present - Niewman-pick disease

94
Q

What is gauchers disease how does it present?

A

lysosomal storage disease which presents with massive splenomegaly.

At Gaucho they serve up massive spleens

95
Q

McArdles disease presentation?

A

Glycogen storage disease -> myalgia and myoglobinuria with exercise

Think of that TV show

96
Q

Where does ADH act?

A

Collecting ducts - collects the water!!!

97
Q

Psoriatic arthritis - HLA?

A

HLA B27

98
Q

a shortened neck and a protruding tongue. There are a number of white spots visible in her iris.

Suggestive of which disorder and genetic abnormality?

A

Downs - Nondisjunction

99
Q

Role of p53 gene?

A

Regulates cell cycle - preventing entry into the S phase until DNA has been checked and repaired

100
Q

HLA DR3 is associated with which disorder?

A

Dermatitis herpetiformis

101
Q

burning pain/paraesthesia in childhood
angiokeratomas

These are features of which disorder?
What else may be seen? What causes this?

A

Fabry disease - caused by deficiency of alpha-galactosidase A (X-linked recessive)

Proteinuria + early cardiovascular disease

102
Q

Which abx should be avoided in breastfeeding?

A

Ciprofloxacin,
tetracycline,
chloramphenicol,
sulphonamides

103
Q

Which psych drugs are CI in breast feeding?

A

lithium, benzodiazepines, clozapine

104
Q

Which drugs non-psych / abx should be avoided in breastfeeding?

A

aspirin
carbimazole
methotrexate
sulfonylureas
cytotoxic drugs
amiodarone

105
Q

What is Tay-Sachs disease?

A

An AR inherited lysosomal storage disorder due to mutated HEXA gene

more common in ashkenazi jews

106
Q

Haemophilia A inheritance?

A

X linked recessive

107
Q

What are TH1 v TH2 cells

A

Th1 = IFN gamma, 2,3,4 + type 4 hypersensitivity

Th2 = IgE, 4,5,6,10,13 (all the higher numbers of IL) - involved in humoral immunity (ab)

108
Q

What is a silent mutation?

A

A mutation that does not change the amino acid, often base change in 3rd position of codon

109
Q

What is a nonsense mutation?

A

A mutation that results in a stop codon

110
Q

What is a Missense mutation?

A

A point mutation that changes the amino acid sequence, which in turn may make the protein non-functional

111
Q

What is a frameshift mutation?

A

Caused by insertion or deletion of a number of nucleotides which results in the subsequent reading of the DNA ‘downstream’ being completely wrong

112
Q

Blue sclera

What investigation distinguishes between the different ddx?

A

osteogenesis imperfecta - normal homogentisic acid

Alkaptonuria - raised homogentisic acid

113
Q

MoA of NO?

A

vasodilation + inhibits platelet aggregation

114
Q

Wilson and Junger criteria for screening tests?

A
  1. The condition should be an important public health problem
  2. There should be an acceptable treatment for patients with recognised disease
  3. Facilities for diagnosis and treatment should be available
  4. There should be a recognised latent or early symptomatic stage
  5. The natural history of the condition, including its development from latent to declared disease should be adequately understood
  6. There should be a suitable test or examination
  7. The test or examination should be acceptable to the population
  8. There should be agreed policy on whom to treat
  9. The cost of case-finding (including diagnosis and subsequent treatment of patients) should be economically balanced in relation to the possible expenditure as a whole
  10. Case-finding should be a continuous process and not a ‘once and for all’ project
115
Q

HLA DR2 conditions associated?

A

Dr - has 2 good features - He is Nice and Good :)

DR2 - Narcolepsy and Goodpasture

116
Q

Which statistical test to use for correlation between two things?

A

parametric (normally distributed): Pearson’s coefficient

non-parametric: Spearman’s coefficient

Some weird correlation between pearson and spearman however pearson is a normal name and spearing a man is not a normal thing to do

117
Q

Which condition are girls with X linked recessive disorders likely to have and why?

A

Turners as there is only one X chromosome

118
Q

What are the different phases of clinical trials?

A

0 Exploratory studies - small n number asess pharmacokinetics + dynamics

I Safety assessment - done on healthy volunteers

II Assess efficacy - IIa optimal dosing, IIb assessing efficacy (small numbers with disease)

III Assess effectiveness - 100-1000s usualy RCT v established mx

IV Postmarketing surveillance - Monitors for long-term effectiveness and side-effects

119
Q

What is the most common cardiac issue in downs?

A

Endocardial cushion defects - aka atrioventricular septal defect (AVSD) or atrioventricular canal defect

120
Q

is the probability of obtaining a result by chance at least as extreme as the one that was actually observed, assuming that the null hypothesis is true

Means what?

A

This is the p value

121
Q

What can linear regression be used for?

A

When analysing data on a scatter plot, linear regression may be used to predict how much one variable changes when a second variable is changed

122
Q

Interferon-alpha where is this produced and what action does this have?

A

Produced by leucocytes and has antiviral action

123
Q

Interferon-beta where is this produced and what action does this have?

A

Produced by fibroblasts and has anti-viral action

Reduces the frequency of exacerbations in patients with relapsing-remitting MS

124
Q

Interferon-gamma where is this produced and what action does this have?

A

Mainly made by NK cells and also TH1 cells

Weaker antiviral action - more of a role in immunomodulation, particularly macrophage activation

125
Q

What is associated with HLA DR4

A

Type 1 diabetes mellitus*

Rheumatoid arthritis - in particular the DRB1 gene (DRB104:01 and DRB104:04 hence the association with DR4)

126
Q

Proportion of different immunoglobulins in the blood?

A

IgG 75%
IgA 15%
IgM 10%
IgD 1%
IgE 0.1%

GAMDE

127
Q

Which type of studies are commonly affected by recall bias?

A

Case-control studies

128
Q

Penetrance v expressivity? examples of diseases?

A

Penetrance = describes ‘how likely’ it is that a condition will develop
eg. incomplete penetrance = retinoblastoma, huntingtons v achondroplasia = complete (100%) penetrance

Expressivity = describes the ‘severity’ of the phenotype
eg high expressivity = NFib

129
Q

What can influence penetrance and expressivity?

A

Modifier genes
Environmental factors
Allelic variation

130
Q

Which one of the following types of immunoglobulins are responsible for haemolytic blood transfusion reactions?

A

IgM

131
Q

Most commonly produced immunoglobulin in the body?

A

IgA

132
Q

IL-8 source and role?

A

Produced by macrophages important for neutrophil chemotaxis

133
Q

Where is IL 12 produced and what does this do?

A

Dendritic cells, macrophages, B cells all produce IL-12 and this activates NK cells and stimulates differentiation of naive T cells into Th1 cells

134
Q

Where is TNFa produced and what does it do?

A

Macrophages prodcue TNFa which induces fever and induces neutrophil chemotaxis

135
Q

IL-10 where is this produced and what is its role?

A

IL-10 is produced by TH2 cells and it:

  • inhibits Th1 cytokine production
  • AKA human cytokine synthesis inhibitory factor and is an ‘anti-inflammatory’ cytokine
136
Q

Which immunoglobulin is involved in activation of B cells?

A

IgD

137
Q

What provides immunity against parasites and how?

A

IgE synthesised by plasma cells activates eosinophils leading to attack parasitic infections

138
Q

hyperacute organ rejection is caused by which cell?

A

B cells

139
Q

What cells act as APCs?

A

B cells

140
Q

Which cells recognise MHC I and MHC II molecules?

A

MHC I = Cytotoxic T cells

MHC II = Helper T cells

141
Q

What antigens are expressed by Hepler T cells and cytotoxic T cells?

A

Helper T cells - CD4, CD3, TCR + CD28

Cytotoxic T cells - CD8, CD3, TCR

142
Q

Which cells mediates acute and chronic organ rejection?

A

Helper T cells + Cytotoxic T cells

143
Q

Which cell of the adaptive immune response is a major source of IL2

A

Helper T cells

144
Q

Intention to treat analysis - what to do if people drop out of trial?

A

include patients who dropped out of trial

145
Q

Relative risk reduction calculation?

A

(EER - CER) / CER

146
Q

WT1 gene mutation is associated with?

A

Wilms tumour - this is the tumour supressor gene associated with this

147
Q

Tumour suppressor genes examples

A

p53
APC - Colorectal ca
BRAC1 + 2
NF1
Rb - retinoblastoma
WT1 - Wilms tumour
Multiple tumor suppressor 1 (MTS-1, p16) - Melanoma

148
Q

What is a cohort study used for?

A

Observational and prospective. Two (or more) are selected according to their exposure to a particular agent (e.g. medicine, toxin) and followed up to see how many develop a disease or other outcome.

The usual outcome measure is the relative risk.

149
Q

What is a case control study used for what is the outcome mesaure?

A

Observational and retrospective.

Patients with a particular condition (cases) are identified and matched with controls. Data is then collected on past exposure to a possible causal agent for the condition.

The usual outcome measure is the odds ratio.

Inexpensive, produce quick results
Useful for studying rare conditions
Prone to confounding

150
Q

What does a cross sectional study do and what does it tell us?

A

Provide a ‘snapshot’, sometimes called prevalence studies

Provide weak evidence of cause and effect

151
Q

Fundoscopy demonstrates peripapillary telangiectasia

Which condition may this be seen in? inheritance?

A

Lebers hereditary optic neuropathy

Mitochondrial inheritance

152
Q

achondroplasia - mutation in what gene and inheritancce?

A

Gain of function mutation in the FGFR3 (fibroblast growth factor receptor) gene

AD inheritance

153
Q

How to calculate Likelihood ratio for a netgative / positive test result? what does this mean?

A

Likelihood ratio for a positive test result = sensitivity / (1 - specificity) - How much the odds of the disease increase when a test is positive

Likelihood ratio for a negative test result = (1 - sensitivity) / specificity - How much the odds of the disease decrease when a test is negative

154
Q

CA 15-3 - use and which ca?

A

Marker used for breast cancer therapy monitoring

155
Q

How to calculate relative risk?

A

Relative risk = EER / CER

156
Q

What is the major genetic susceptibility locus for RA?

A

The HLA-DRB1 gene

157
Q

Acute anterior uveitis - HLA?

A

HLA-B27

158
Q

HLA-DQ2/DQ8 - disease?

A

Coeliac

159
Q

HLA-A3 - is associated with?

A

Haemochromatosis

160
Q

HLAs which are class I and class II

A

HLA A, B and C are class I antigens

HLA DP, DQ, DR are class II antigens

161
Q

Describe which is more / less in +ve and -ve skewed distribution?

A

alphabetical order: mean - median - mode

’>’ for positive, ‘<’ for negative

162
Q

What is used to analyse survival over time?

A

Hazard ratio

163
Q

How to calculate down syndrome risk at a given age?

A

Age 20 = 1/5000

Down’s syndrome risk - 1/1000 at 30 years then divide by 3 for every 5 years

164
Q

Levels of evidence?

A

Ia - evidence from meta-analysis of randomised controlled trials
Ib - evidence from at least one randomised controlled trial

IIa - evidence from at least one well-designed controlled trial which is not randomised
IIb - evidence from at least one well-designed experimental trial

III - evidence from case, correlation and comparative studies

IV - evidence from a panel of experts

165
Q

What are the features of Vit D resistant rickets and how is it diagnosed? mx?

A

failure to thrive
normal serum calcium, low phosphate, elevated alkaline phosphotase
x-ray changes: cupped metaphyses with widening of the epiphyses

Diagnosis - increased urinary PO4

Mx - High dose vit D + oral phosphate

166
Q

elfin-like facies
characteristic like affect - very friendly and social
learning difficulties
short stature
transient neonatal hypercalcaemia
supravalvular aortic stenosis

Suggestive of what disorder?

A

Williams

167
Q

Fitness to fly with haem disorders?

A

patients with a haemoglobin of greater than 8 g/dl may travel without problems (assuming there is no coexisting condition such as cardiovascular or respiratory disease)

168
Q

Fitness to travel following surgery?

A

travel should be avoided for 10 days following abdominal surgery

laparoscopic surgery: after 24 hours

colonoscopy: after 24 hours

following the application of a plaster cast, the majority of airlines restrict flying for 24 hours on flights of less than 2 hours or 48 hours for longer flights

169
Q

Flying during pregnancy?

A

most airlines do not allow travel after 36 weeks for a single pregnancy and after 32 weeks for a multiple pregnancy

most airlines require a certificate after 28 weeks confirming that the pregnancy is progressing normally

170
Q

Fitness to fly with Respiratory disease?

A

pneumonia: should be ‘clinically improved with no residual infection’

pneumothorax: absolute contraindication, the CAA suggest patients may travel 2 weeks after successful drainage if there is no residual air. The British Thoracic Society used to recommend not travelling by air for a period of 6 weeks but this has now been changed to 1 week post check x-ray

171
Q

Fitness to fly with Cardiovascular disease?

A

unstable angina, uncontrolled hypertension, uncontrolled cardiac arrhythmia, decompensated heart failure, severe symptomatic valvular disease: should not fly

uncomplicated myocardial infarction: may fly after 7-10 days

complicated myocardial infarction: after 4-6 weeks

coronary artery bypass graft: after 10-14 days
percutaneous coronary intervention: after 3 days

stroke: patients are advised to wait 10 days following an event, although if stable may be carried within 3 days of the event

172
Q

nephrotic syndrome and sensory neuropathy bilaterally in the arms

Corneal findings + skin findings are suggestive of what dx?

A

Fabrys disease

173
Q

X linked recessive conditions?

A

A - androgen insensitivity syndrome
B - Becker/Duchenne dystrophy
C - colour blindness
D - Diabetes insipidus (nephrogenic)
E - eyes (retinitis pigmentosa)
F - Fabry
G - G6PD deficiency
H - haemophilia A/B, Hunter’s

174
Q

genotype:phenotype correlation in mitochondiral disease?

A

mitochondrial diseases often exhibit poor genotype-phenotype correlation, meaning that the same genetic defect can result in a wide range of clinical manifestations

175
Q

Generally what types of diseases are mitochondrial?

A

Rare neurological ones

176
Q

Man with mitochondrial disease - inheritance to children?

A

None of his children can get it

177
Q

What test is used to assess for mutated oncogenes?

A

Polymerase chain reactions

RT PCR - used for gene expression within tissue sample and cant detect mutations in genome

178
Q

What do leukotrienes do?

A

Mediators of inflammation and allergic reactions

cause bronchoconstriction, mucous production

increase vascular permeability, attract leukocytes

leukotriene D4 has been identified as the SRS-A (slow reacting substance of anaphylaxis)

179
Q

Tell me about leukotriene production?

A

Secreted by leukocytes formed from arachidonic acid by action of lipoxygenase

NSAID induced bronchospasm in asth

180
Q

What disorders are caused by deletion of chromosome 15?

A

Prader-Willi - paternal - microdeletion of paternal 15q11-13 (70% of cases), also maternal uniparental disomy of chromosome 15

AngelMan syndrome - maternal

181
Q

When to use ANOVA test?

A

One-way analysis of variance analysis (ANOVA) - used for parametric/approximately normally distributed data, when the mean needs to be compared for more than 2 groups

182
Q

Turners has increased risk of what GI disorder?

A

Crohns

183
Q

Different phases of cell division?

A

Prophase Chromatin in the nucleus condenses

Prometaphase Nuclear membrane breaks down allowing the microtubules to attach to the chromosomes

Metaphase Chromosomes aligned at middle of cell

Anaphase The paired chromosomes separate at the kinetochores and move to opposite sides of the cell

Telophase Chromatids arrive at opposite poles of cell

Cytokinesis Actin-myosin complex in the centre of the cell contacts resulting in it being ‘pinched’ into two daughter cells

184
Q

What is involved in control of respiration? what triggers these?

A

Central regulatory centres
- medullary respiratory centre
- apneustic centre (lower pons)
- pneumotaxic centre (upper pons)

Central + peripheral chemoreceptors
- central: raised [H+] in ECF stimulates respiration
- peripheral: carotid + aortic bodies, respond to raised pCO2 & [H+], lesser extent low pO2

Pulmonary receptors
- stretch receptors, lung distension causes slowing of respiratory rate (Hering-Bruer reflex)
- irritant receptor, leading to bronchoconstriction
- juxtacapillary receptors, stimulated by stretching of the microvasculature

185
Q

Main features of homocystinuria?

A

Musc: Marfinoid appearance, osteoporosis, kyphosis

Neuro - LD + seiures

Ocular - myopia + downward dislocation of lens

Arterial + VTE

Malar flush + livedo reticularis

NB no risk of renal stones - this is seen in cystinuria

186
Q

cyanide-nitroprusside test - when is this +ve?

A

Homocystinuria + cystinuria (latter = risk of renal stones)

187
Q

Which part of cell cycle does Vincristine act on?

A

Metaphase - when chromosomes align at the middle at of the cell and then begin to separate

Vincristine binds to the tubulin protein, preventing the formation of microtubules and preventing the initiation of chromosome separation -> apoptosis

188
Q

What condition presents similarly to Turners but in men? What is the karyotype?

A

Noonans - similar but also PV stenosis, triangular face, low set ears, factor 11 deficiency

Normal karyotype caused by AD defect in chromosome 12

189
Q

Examples of trinucleotide repeat disorders?

A

Trineucleotide Repeat Disorders Mnemonic:
‘My fragile Friend Hunts for Spine and Teeth’

Myotonic dystrophy (CTG)
Fragile X (CGG)
Friedreich’s ataxia* (GAA)
Huntington’s (CAG)
Spinocerebellar ataxia
Spinobulbar muscular atrophy
Dentatorubral pallidoluysian atrophy

190
Q

Which conditions are Inf-a useful in?

A

Hepatitis B & C,

Kaposi’s sarcoma,

metastatic renal cell cancer,

hairy cell leukaemia

191
Q

Plasma viscosity in GCA?

A

Raised just like ESR and CRP

192
Q

Describe types of hypersenitivity reactions?

A

Type I - Anaphylactic

Type II - Cell bound

Type III - Immune complex

Type IV - Delayed hypersensitivity

Type V - Antibodies recognise and bind to cell surfaces eg MG and Graves

193
Q

Juvenile gout, is characterized by hyperuricemia + orange coloured sand secondary to hyperuricemia

Dx and inheritanced?

A

Lesch-Nyhan syndrome, X linked recessive

194
Q

How to calculate pre-test and post-test probability?

A

Pre-test probability = Prevalence of condition

Post-test probability = post test odds / 1 + post test odds

195
Q

How to calculate pre-test and post-test odds?

A

Pre-test odds = pre-test probability / (1 - pre-test probability)
The odds that the patient has the target disorder before the test is carried out

Post-test odds = pre-test odds x likelihood ratio of +ve test
The odds that the patient has the target disorder after the test is carried out

where the likelihood ratio for a positive test result = sensitivity / (1 - specificity)

196
Q

Which receptors do INF-a. INF-b and INF-y bind to?

A

IFN-alpha and IFN-beta bind to type 1 receptors

IFN-gamma binds only to type 2 receptors.

197
Q

Adverse effects of INF-a mx?

A

flu-like symptoms and depression

198
Q

Fluorescence in situ hybridisation (FISH) - usec case?

A

Fluorescence in situ hybridisation uses a labelled probe to detect a genomic sequence on a chromosome and is less sensitive than PCR

170
120 - new -> 18
50 old -> 10

199
Q

Intelligence in Turners?

A

Normal

200
Q

Features of congenital toxo?

A

Cerebral calcification
Chorioretinitis
Hydrocephalus