Clinical Sciences and Statistics Flashcards
1
Q
LVEF = ?
A
(SV / EDV) x 100
Left Ventricular ejection fraction = (Stroke volume/ End diastolic volume) x 100
Stroke volume (end diastolic - end systolic)
2
Q
Standard error of the mean = ?
A
Standard error of the mean = standard deviation / square root (number of patients)
3
Q
The power of a study is…
A
The power of a study is the probability of (correctly) rejecting the null hypothesis when it is false, i.e. the probability of detecting a statistically significant difference
4
Q
where is phosphate reabsorbed?
A
proxmial tubule
5
Q
What electrolytes are absorbed in the distal tubule (3)
A
sodium
potassium
calcium
6
Q
Relative risk reduction = ?
A
Relative risk reduction = (EER - CER) / CER
EER = experimental event rate CER = control event rate
7
Q
Most immunoglobulin and antibodies are produced by…
A
plasma cells
8
Q
Blood smear result for DIC
A
Schistocytes
9
Q
p53 plays a crucial role in the cell cycle, it is responsible for…
A
Preventing entry into the S phase until DNA has been checked and repaired
10
Q
Outline the 5 steps of atherosclerosis
A
- Endothelial dysfunction triggered by smoking, hypertension or hyperglycaemia.
- Pro-inflammatory, pro-oxidant, proliferative changes in the endothelium.
- Fatty infiltration of the subendothelial space by low-density lipoprotein (LDL).
- Macrophages phagocytose oxidised low-density lipoprotein.
- Smooth muscle proliferation and migration from the tunica media into the intima.
11
Q
Peroxisome main function
A
Catabolism of long chain fatty acids (poly peptides)
12
Q
Proteasome main function
A
degradation of protein molecules that have been tagged with ubiquitin
13
Q
Ribosome main function
A
translation of RNA into proteins
14
Q
Nucleolus main function
A
Ribosome production
15
Q
Lysosome main function
A
breakdown of polysaccharides and proteins
16
Q
Nucleus main function
A
DNA maintenance
RNA transcription
RNA splicing
17
Q
Mitochondria main function
A
aerobic respiration
18
Q
Golgi apparatus main function
A
- packages molecules that are destined for cell secretion
- adds mannose-6-phosphate to proteins for transport to lysosome
19
Q
Smooth endoplasmic reticulum main function
A
steroid, lipid synthesis
example of cells with SER: adrenal cortex, hepatocytes, testes, ovaries
20
Q
Rough endoplasmic reticulum
A
translation and folding of new proteins
manufacture of lysosomal enzymes
site of N-linked glycosylation
examples of cells with extensive RER include pancreatic cells, goblet cells, plasma cells
21
Q
Interferon-γ main source and function
A
T helper 1 cells
activates macrophages
22
Q
Tumour necrosis factor (TNF) main source and function
A
Macrophage
induce fever, neutrophil chemotaxis
23
Q
Likelihood ratio for a positive test result = ?
A
sensitivity/ (1 - specificity)
24
Q
Likelihood ratio for a negative test results =?
A
(1 - sensitivity)/ specificity
25
Type 1 hypersensitivity
mechanism
examples
IgE
| anaphylaxis, atopy
26
Type 2 hypersensitivity
mechanism
examples (guess a few)
```
IgG/ IgM
Autoimmune haemolytic anaemia
• ITP
• Goodpasture's syndrome
• Pernicious anaemia
• Acute haemolytic transfusion reactions
• Rheumatic fever
• Pemphigus vulgaris / bullous pemphigoid
```
27
Type 3 hypersensitivity
mechanism
examples
IgG, IgA - free antigen and antibody combine
• Serum sickness
• Systemic lupus erythematosus
• Post-streptococcal glomerulonephritis
• Extrinsic allergic alveolitis (especially acute phase)
28
Type 4 hypersensitivity
mechanism
examples
```
T cell mediated
• Tuberculosis / tuberculin skin reaction
• Graft versus host disease
• Allergic contact dermatitis
• Scabies
• Extrinsic allergic alveolitis (especially chronic phase)
• Multiple sclerosis
• Guillain-Barre syndrome
```
29
Type 5 hypersensitivity
mechanism
examples
Antibodies bind to cell surfaces
Graves
Myasthenia gravis
30
```
Vitamin B3 (Niacin) deficiency - Pellagra
Features (3)
```
diarrhoea
dermatitis
dementia
31
```
Antidiuretic hormone (ADH) is secreted from the [X]. It promotes water reabsorption in the [Y] of the kidneys by the insertion of [Z].
eg. Desmopressin
```
X - posterior pituitary gland
Y - collecting ducts
Z - aquaporin 2 channels
32
Number needed to treat = ?
NNT = 1/ ARR
ARR = absolute risk reduction
33
Absolute risk reduction =
control event rate - experiment event rate
34
Layers of the skin (5)
1. Stratum corneum - Flat, dead, scale-like cells filled with keratin
Continually shed
2. Stratum lucidum - Clear layer - present in thick skin only
3. Stratum granulosum - Cells form links with neighbours
4. Stratum spinosum - Squamous cells begin keratin synthesis
Thickest layer of epidermis
5. Stratum germinativum - The basement membrane - single layer of columnar epithelial cells
Gives rise to keratinocytes
Contains melanocytes
35
Variance is a measure of the spread of scores away from the mean.
Variance = ?
Variance = square of standard deviation
36
6 stages of Mitosis
1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
37
Mitosis steps 1 + 2
Prophase - Chromatin in the nucleus condenses
| Prometaphase - Nuclear membrane breaks down allowing the microtubules to attach to the chromosomes
38
Mitosis steps 3 + 4
Metaphase - Chromosomes aligned at middle of cell
| Anaphase - The paired chromosomes separate at the kinetochores and move to opposite sides of the cell
39
Mitosis steps 5 + 6
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
40
P value is...
P value - 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
41
Significance tests
| Parametric (2)
Parametric tests (something that can be measured, usually normally distributed)
Student's t-test - paired or unpaired*
Pearson's product-moment coefficient - correlation
42
Significance test
| Non-parametric (4)
Non-parametric tests:
- Mann-Whitney U test - compares ordinal, interval, or ratio scales of unpaired data
- Wilcoxon signed-rank test - compares two sets of observations on a single sample, e.g. a 'before' and 'after' test on the same population following an intervention
- Chi-squared test - used to compare proportions or percentages e.g. compares the percentage of patients who improved following two different interventions
- Spearman, Kendall rank - correlation
43
Acute tubular necrosis microscopy
granular, muddy-brown urinary casts
44
Clinical trials
Phase Goal Notes
I Determines pharmacokinetics and pharmacodynamics and side-effects prior to larger studies Conducted on healthy volunteers
II Assess efficacy + dosage Involves small number of patients affected by particular disease
May be subdivided into
IIa - assesses optimal dosing
IIb - assesses efficacy
III Assess effectiveness Typically involves 100-1000's of people, often as part of a randomised controlled trial, comparing new treatment with established treatments
IV Postmarketing surveillance Monitors for long-term effectiveness and side-effects
45
CD cluster
Cluster of differentiation Function
CD1 MHC molecule that presents lipid molecules
CD2 Found on thymocytes, T cells, and some natural killer cells that acts as a ligand for CD58 and CD59 and is involved in signal transduction and cell adhesion
CD3 The signalling component of the T cell receptor (TCR) complex
CD4 Found on helper T cells.
Co-receptor for MHC class II
Used by HIV to enter T cells
CD5 Found in the majority of mantle cell lymphomas
CD8 Found on cytotoxic T cells.
Co-receptor for MHC class I
Found on a subset of myeloid dendritic cells
CD14 Cell surface marker for macrophages
CD15 Expressed on Reed-Sternberg cells (along with CD30)
CD16 Bind to the Fc portion of IgG antibodies
CD21 Receptor for Epstein-Barr virus
CD28 Interacts with B7 on antigen presenting cell as costimulation signal
CD45 Protein tyrosine phosphatase present on all leucocytes
CD56 Unique marker for natural killer cells
CD95 Acts as the FAS receptor, involved in apoptosis
46
standard error of the mean
Standard error of the mean = standard deviation / square root (number of patients)
47
Troponin T binds to...
Troponin T binds to tropomyosin, forming a troponin-tropomyosin complex
48
what bias is a particular problem in case-control studies
recall bias
49
Selection bias is...
Error in assigning individuals to groups leading to differences which may influence the outcome.
eg. sampling bias, volunteer bias, non-responder bias
50
Bias found in non-blinded trials. Observers subconsciously report data in a way that favours the expected outcome.
Expectation bias (Pygmalion effect)
51
Hawthorn effect describes...
Describes a group changing it's behaviour due to the knowledge that it is being studied
52
X linked dominant conditions (3)
alports
retts
Vit D resistent rickets
53
Post-test probability = ?
Post-test probability = post test odds / (1 + post-test odds)
54
Cohort study usual outcome measure...
relative risk
55
Turner's most common cardiac abnormality
bicuspid aortic valve
56
Cytokines - Main source + function
TNF a
IFN y
TNF a - from macrophage - induce fever, neutrophil chemotaxis
INF y - from Th1 cells - activate macrophage
57
ADH (diabetes insipidus) is from [X} and acts upon [Y]
X - hypothalamus (supraoptic nuclei)
| Y - collecting ducts
58
Adrenal cortex mnemonic
Adrenal cortex mnemonic: GFR - ACD
Glomerulosa - Aldosterone (mineral corticoid)
Fasciculata - Cortisone (glucocorticoid)
Reticularis - DHEA (androgens)
59
Adrenaline acts via
G protein coupled receptors
60
Tay-Sachs
| features
Developmental delay, Cherry red spot on macula, Nil hepato/ splenomegaly
Normally around 6 months old
61
Insulin binds to what receptor
Tyrosine kinase
62
C1q, C1rs, C2, C4 deficiency association
immune complexes - HSP, SLE
63
C3 Deficiency association
recurrent bacterial infections
64
C5 deficiency
Leiner disease, diarrhoea, dermatitis
65
C5-9 deficiency
Neisseria Meningitidis
66
Subunits of troponin bind to...
Trop C
Trop T
Trop I
C - Calcium
T - Tropomysin - forms Troponin-tropomysin complex
I - Actin
67
```
Homocystinuria
inheritance
pathophys
features
Ix
Mx
```
autosomal recessive
P - deficiency of cystathionine beta synthase
Fx - Marfinoid, learning difficulty, downward dislocation of lens
Ix - cyanide-nitroprusside test
Mx - Vitamin B6 (Pyridoxine)
68
X-linked recessive conditions
| female carriers -> 50% male effected; 50% female carrier; nil male-male transmission, females never effected
Muscular dystrophy, colour blindness, G6PD def, Haemophillia A, Nephrogenic DI, Fabrys... amongst others
69
What supplement aids iron absorption in the gut?
Vitamin C (ascorbic acid)
70
Case control outcome measure...
Odds ratio
71
cohort study outcome measure...
relative risk
72
HLA antigens encoded on which chromosome?
chromosome 6
73
dry beriberi is..
thiamine deficiency leading to peripheral neuropathy
74
wet beriberi is...
thiamine deficiency with heart failure
75
Riboflavin is required for...
Hydrogen-transfer chain in mitochondria and production of ATP
76
Features of Mitochondrial inheritance (is female only) (5)
```
optic atrophy
neuropathy
diabetes
epilepsy
sensory neural hearing loss
```
77
femoral nerve sensory supplies the
anterior-medial thigh
78
Median nerve palsy
weakness of thumb abduction (abductor policis brevis)
79
Ulnar nerve palsy
Inability to abduct or adduct fingers
80
Radial nerve palsy
Wrist drop
81
Gilbert's syndrome Features (2)
```
painless jaundice (normal LFTs other than BR)
non-specific illness
```
82
Hypoglossal (CN XII) palsy
tongue deviates TOWARDS the side of defect - due to paralysis of tongue muscles
83
Antiphospholipid syndrome antibodies (3)
B2 glycoprotein, lupus anticoagulant, anti-cardiolipin
84
Causes of Respiratory Alkalosis - causes of hyperventilation
```
Pregnancy
Anxiety
Hepatic failure
salicylates, progresterone
interstitial lung disease
```
85
Peutz-Jeghers syndrome Features (3)
hyperpigmentation nose and mouth
GI bleeding
Risk of colon, pancreatic ca
86
Marfans gene abnormality
Fibrillin-1
87
Analysis of variance (ANOVA) statistical analysis description
comparison of two of more means
88
Primary biliary cholangitis antibody
Anti mitochondrial M2
89
Iron overdose antidote
Desferrioxamine
90
Pancreatic Ca gene mutation
KRAS
91
Hereditary spherocytosis gene mutation
Spectrum and ankyrin
92
Autoimmune encephalitis antibody
Anti LGI 1 (previously VGKC)
93
acute intermittent porphyria Mx
IV haem arginate
94
RET oncogene related to which type of thyroid cancer
medullary
95
Alkaptonuria/ Ochronosis features (2) - homogensitic acid oxidase deficiency
Chondrocalcinosis + arthritis
| brown/ dark urine
96
Respiratory alkalosis drug overdose causes (2)
salicylates (aspirin)
theophylline
(hyperventilation)
97
Sjogrens disease antibodies
Anti RO
| Anti La
98
Mixed Connective tissue disaese
features
autoantibody
F - raynauds, ILD, pericarditis
| Antibody - Anti-Ribonucleoprotein
