EK ICS Flashcards
1
Q
Define inflammation.
A
A local physiological response to tissue injury or infection using different types of cells and molecules.
2
Q
Give a benefit of inflammation.
A
Inflammation can destroy invading micro-organisms and can prevent the spread of infection.
3
Q
Give a disadvantage of inflammation.
A
Inflammation can produce disease and can lead to distorted tissues with permanently altered function.
4
Q
What are the 4 outcomes of inflammation?
A
- Resolution. 2. Suppuration. 3. Organisation (scar tissue formation). 4. Progression onto chronic inflammation.
5
Q
Give 6 causes of acute inflammation.
A
- Microbial infections (bacteria and viruses). 2. Chemicals (corrosives, acids/alkalis). 3. Physical agents (trauma, burns, frost bite). 4. Hypersensitivity reactions 5. Bacterial toxins. 6. Tissue necrosis.
6
Q
How do blood vessels respond in inflammation?
A
- Blood vessels around the site dilate and leak a protein-rich fluid exudate - Endothelial cells become sticky in areas of inflammation so that inflammatory cells adhere to them, and become porous to allow them to pass into tissue. - the smooth muscle of arteriolar walls form precapillary sphincters which regulate Blood flow into the capillary bed. in acute inflammation, these sphincters relax to increase the Blood flow through the capillaries
7
Q
Give 5 cardinal signs of inflammation.
A
- Redness (rubor): due to dilation 2. Swelling (tumor): due to oedema 3. Pain (dolor): due to stretching and distortion of tissues, and chemical mediators of AI 4. Heat (calor): due to hyperaemia 5. Loss of function: movement is inhibited by pain
8
Q
How can acute inflammation be diagnosed histologically?
A
By looking for the presence of neutrophil polymorphs.
9
Q
Give 3 endogenous chemical mediators of acute inflammation.
A
- Bradykinin. 2. Histamine. 3. Nitric Oxide.
10
Q
What are 4 systemic effects of acute inflammation?
A
- Fever. 2. Feeling unwell. 3. Weight loss. 4. Reactive hyperplasia of the reticuloendothelial system.
11
Q
What cells are involved in chronic inflammation?
A
Macrophages and B and T lymphocytes.
12
Q
What cell can form when several macrophages try to ingest the same particle?
A
Multinucleate giant cell.
13
Q
Give 4 causes of chronic inflammation.
A
- Primary chronic inflammation. 2. Transplant rejection. 3. Recurrent acute inflammation. 4. Progression from acute inflammation.
14
Q
Give examples of primary chronic inflammation.
A
- Infective substances having resistance to phagocytosis e.g. TB, leprosy. 2. Endogenous materials e.g. uric acid crystals. 3. Exogenous materials e.g. asbestos. 4. Autoimmune diseases e.g. chronic gastritis, rheumatoid arthritis etc. 5. Other chronic inflammatory diseases e.g. chronic inflammatory bowel disease.
15
Q
In which type of inflammation would you see neutrophil polymorphs?
A
Acute inflammation.
16
Q
What are some macroscopic features of chronic inflammation?
A
- Chronic ulcer. 2. Chronic abscess cavity. 3. Granulomatous inflammation. 4. Fibrosis.
17
Q
What is granulation tissue?
A
Granulation tissue is composed of small blood vessels in a connective tissue matrix with myofibroblasts. It is important in healing and repair.
18
Q
Define granuloma.
A
Collection of macrophages attempting to kill bacteria, surrounded by lymphocytes.
19
Q
Give an example of a granulomatous disease.
A
TB, leprosy, Crohn’s disease and sarcoidosis.
20
Q
The activity of what enzyme in the blood can act as a marker for granulomatous disease?
A
Angiotensin converting enzyme.
21
Q
What kind of disease is TB?
A
A granulomatous disease.
22
Q
What is the difference between resolution and repair?
A
Resolution is when the initiating factor is removed and the tissue is undamaged or able to regenerate. In repair, the initiating factor is still present and the tissue is unable to regenerate.
23
Q
Name 5 types of cells capable of regeneration.
A
- Hepatocytes. 2. Osteocytes. 3. Pneumocytes. 4. Blood cells. 5. Gut and skin epithelial cells.
24
Q
Name 2 types of cells that are incapable of regeneration.
A
- Myocardial cells.| 2. Neuronal cells.
25
Define abscess.
A localised collection of pus in a cavity, formed from tissue which had been broken down by infectious bacteria.
26
Define thrombosis.
Formation of a solid mass from blood constituents in an intact vessel in the living.
27
Give 3 reasons why thrombosis formation is uncommon.
1. Laminar flow 2. Endothelial cells lining the blood vessels are not sticky when healthy 3. Clot-forming cells and proteins are inactive
28
What are the 3 factors that can lead to thrombosis formation?
1. Change in vessel wall. 2. Change in blood constituents. 3. Change in blood flow.
29
Define embolus and give examples
A mass of material in the circulation that is able to become lodged in a vessel and block it. - Usually a thrombus - Air from IVs - Cholesterol crystals - Tumour - Amniotic fluid - Fat (in severe trauma)
30
Define ischaemia.
Reduction in blood flow to a tissue due to a thrombus, embolus, or heart failiure. Reversible tissue damage as a result of impaired vascular perfusion depriving tissues of nutrients and oxygen.
31
Define infarction.
Irreversible tissue death due to ischaemia.
32
Why are tissues with an end arterial supply more susceptible to infarction?
They only have a single arterial supply and so if this vessel is interrupted infarction is likely.
33
Give 3 examples of organs with a dual arterial supply.
1. Lungs (bronchial arteries and pulmonary veins). 2. Liver (hepatic arteries and portal veins). 3. Some areas of the brain around the circle of willis.
34
What can happen if ischaemia is rectified?
Re-perfusion injury can occur due to the release of waste products.
35
What are the consequences of an arterial embolus?
An arterial embolus can go anywhere! The consequences could be stroke, MI, gangrene etc.
36
What are the consequences of a venous embolus?
An embolus in the venous system will go onto the vena cava then through the pulmonary arteries, and will become lodged in the lungs causing a pulmonary embolism. This means there is decreased perfusion to the lungs.
37
Through which blood system would an embolus have travelled if it resulted in a pulmonary embolism?
Venous system.
38
What drug can be used to prevent Thrombosis?
Aspirin.
39
Define atherosclerosis.
The accumulation of fibrolytic plaques in the intima of systemic arteries. It is an inflammatory process.
40
Is atherosclerosis more common in the systemic or pulmonary circulation?
It is more common in the systemic circulation because this is a higher pressure system.
41
What are the 3 main constituents of an atheromatous plaque?
1. Lipids. 2. Fibrous tissue. 3. Lymphocytes.
42
Give 5 risk factors for atherosclerosis.
1. Family history of cardiovascular disease 2. Increasing age (more fatty streaks and microthrombi) 3. Smoking (more endothelial cell damage, inflammation) 4. High levels of LDL's. 5. Obesity (more inflammation) 6. Poorly controlled diabetes (more endothelial cell damage) 7. Hypertension (more EC damage)
43
What can be done to prevent atherosclerosis?
Reduce risk factors and taking low dose aspirin regularly.
44
What is the primary cause of atherosclerosis?
Endothelial cell damage.
45
Why can cigarette smoking lead to atherosclerosis?
Cigarette smoking releases free radicals, nicotine and CO into the body. These all damage endothelial cells.
46
Why can hypertension lead to atherosclerosis?
A higher blood pressure means there is a greater force exerted onto the endothelial cells and this can lead to damage.
47
Define apoptosis.
Programmed cell death of a single cell.
48
What is the role of p53 protein?
p53 protein looks for DNA damage, if damage is present p53 switches on apoptosis.
49
What protein can switch on apoptosis if DNA damage is present?
p53 protein.
50
Activation of which family of protease enzymes can turn on apoptosis?
Caspases.
51
Activation of what receptor can activate caspase and therefore apoptosis?
FAS receptor.
52
Give an example of a disease where there is a lack of apoptosis.
Cancer; mutations in p53 mean cell damage isn't detected.
53
Give an example of a disease where there is too much apoptosis.
HIV.
54
Define necrosis.
Unprogrammed death of a large number of cells due to an adverse event.
55
Give 4 examples of events that can lead to necrosis.
1. Frost bite. 2. Avascular necrosis of bone. 3. Infarction. 4. Pancreatitis
56
Give 3 differences between apoptosis and necrosis.
1. Apoptosis is programmed cell death whereas necrosis is unprogrammed. 2. Apoptosis tends to effect only a single cell whereas necrosis effects a large number of cells. 3. Apoptosis is often in response to DNA damage. Necrosis is triggered by an adverse event e.g. frost bite.
57
Define hypertrophy.
Increase in the size of a tissue due to an increase in the size of constituent cells (not cell division)
58
Define hyperplasia.
Increase in the size of a tissue due to an increase in the number of constituent cells.
59
Define atrophy.
Decrease in the size of a tissue due to a decrease in the size of the constituent cells OR due to a decrease in the number of constituent cells.
60
Define metaplasia.
A change in the differentiation of a cell from one fully differentiated cell type to another fully differentiated cell type.
61
Give an example of a disease that demonstrates metaplasia.
Barrett's oesophagus - the cells at the lower end of the oesophagus change from stratified squamous cells to columnar. This is due to basal reserve cells differentiating into squamous cells rather than ciliated cells.
62
Define dysplasia.
Morphological changes seen in cells in the progression to becoming cancer.
63
Define acute inflammation.
Initial and short lived tissue reactions to injury.
64
Define chronic inflammation.
Subsequent and prolonged tissue reactions to injury.
65
What happens to a cell when the telomere gets too short?
It can no longer divide.
66
Give an example of:a) a dividing tissue.b) a non dividing tissue.
a) Gut or skin tissue can divide. b) Brain tissue is non dividing.
67
Why can excision be used as a cure for basal cell carcinoma?
Because BCC doesn't metastasise.
68
Suggest a treatment that could be used for leukemia?
Chemotherapy. Leukemia is systemic, it circulates all around the body, therefore excision can't be used.
69
Define carcinoma.
Malignant tumour of epithelial tissue.
70
Give examples of 5 carcinomas that can spread to bone.
1. Breast. 2. Kidney. 3. Lung. 4. Prostate. 5. Thyroid.
71
Give an example of a carcinoma that can spread to the axillary lymph nodes.
Breast carcinomas.
72
Why is adjuvant therapy often used in the treatment of carcinomas?
Micrometastes are possible even if a tumour is excised and so adjuvant therapy is given to suppress secondary tumour formation.
73
Give an advantage and a disadvantage of conventional chemotherapy.
Advantage: works well for treatment against fast dividing tumours e.g. lymphomas. Disadvantage: it is non selective for tumour cells, normal cells are hit too; this results in bad side effects such as diarrhoea and hair loss.
74
What kind of carcinomas would targeted chemotherapy be most effective against?
Slower dividing tumours e.g. lung, colon and breast.
75
What is the theory behind targeted chemotherapy?
It exploits the differences between cancer cells and normal cells; this means it is more effective and has less side effects.
76
What kind of drugs can be used in targeted chemotherapy?
Monoclonal antibodies (MAB) and small molecular inhibitors (SMI).
77
What is required for a tumour to invade through a basement membrane?
1. Proteases eg collagenases 2. Cell motility.
78
What is required for a tumour to enter the blood stream (intravasation)?
1. Collagenases. 2. Cell motility.
79
What is required for a tumour to exit the blood stream (extravasation)?
1. Adhesion receptors. 2. Collagenases. 3. Cell motility.
80
Give 2 promoters of tumour angiogenesis.
1. Vascular endothelial growth factors. 2. Fibroblast growth factors.
81
Give 3 inhibitors of tumour angiogenesis.
1. Angiostatin. 2. Endostatin. 3. Vasculostatin.
82
What 3 mechanisms do tumour cells use to evade host immune defence in the blood?
1. Platelet aggregation. 2. Adhesion to other tumour cells. 3. They shed surface antigens so as to 'distract' lymphocytes.
83
Give an example of a malignant tumour that often spreads to the lung.
Sarcoma (via venae cavae -> heart -> pulmonary arteries).
84
Give an example of carcinomas that can spread to the liver.
Colon, stomach and pancreatic carcinomas can spread to the liver via the portal vein.
85
What causes the pain associated with acute inflammation?
1. Stretching and distortion of tissues due to oedema and pus under high pressure in an abscess cavity. 2. Chemical mediators e.g. bradykinin and prostaglandins, are also known to induce pain.
86
Describe the process of neutrophil polymorph migration into tissues as seen in acute inflammation.
1. Margination of neutrophils. 2. Pavementing of neutrophils. 3. Neutrophils pass between endothelial cells. 4. Neutrophils pass through basal lamina and migrate into adventitia.
87
What is the main source of histamine?
Mast cells; histamine is stored in granules in their cytoplasm.
88
What enzymatic cascade systems does plasma contain?
1. The complement system.2. The kinin system.3. The coagulation system.4. The fibrinolytic system.
89
What is the role of tissue macrophages in acute inflammation?
They secrete chemical mediators that attract neutrophil polymorphs.
90
What is the role of the lymphatic system in acute inflammation?
Lymphatic channels dilate and drain away oedematous fluid therefore reducing swelling. Antigens are also carried to lymph nodes for recognition by lymphocytes.
91
What is the major role of neutrophil polymorphs in acute inflammation?
Phagocytosis!
92
Define carcinogenesis.
A multistep process in which normal cells become neoplastic cells due to mutations.
93
What percentage of cancer risk is due to environmental factors?
85% environmental, 15% genetic.
94
Give 5 host factors that can affect cancer risk.
1. Race.2. Diet. 3. Constitutional factors (gender, age).4. Premalignant conditions. 5. Transplacental exposure.
95
Give an example of a situation when transplacental exposure lead to an increase in cancer risk.
The daughters of mothers who had taken diethylstiboestrol for morning sickness had an increased risk of vaginal cancer.
96
Name the 5 different categories of carcinogens.
1. Viral. 2. Chemical. 3. Ionising and non-ionising radiation. 4. Hormones, parasites and mycotoxins. 5. Miscellaneous e.g. asbestos and metals.
97
What causes skin cancer?
Exposure to UV light.
98
Chemical carcinogens: what types of cancer do polycyclic aromatic hydrocarbons cause?
Lung cancer and skin cancer.
99
Chemical carcinogens: what can expose people to polycyclic aromatic hydrocarbons?
Smoking cigarettes and mineral oils.
100
Chemical carcinogens: what types of cancer do aromatic amines cause?
Bladder cancer.
101
Chemical carcinogens: what types of people are more susceptible to bladder cancer caused by aromatic amine exposure?
People who work in the rubber/dye industry.
102
Chemical carcinogens: what type of cancer do nitrosamines cause?
Gut cancer.
103
Chemical carcinogens: what type of cancer do alkylating agents cause?
Leukaemia; the risk is small in humans.
104
Define neoplasm.
An autonomous, abnormal, persistent new growth.
105
What is a neoplasm composed of?
1. Neoplastic cells.| 2. Stroma.
106
Describe neoplastic cells.
Neoplastic cells are derived from nucleated cells. They're usually monoclonal and their growth is related to the parent cell.
107
Describe the stroma of a neoplasm.
Connective tissue composed of fibroblasts and collagen; it is very dense. There is a lot of mechanical support and blood vessels provide nutrition for the neoplastic cells.
108
What is essential for neoplasm growth?
Angiogenesis.
109
What does a neoplasm release in order to initiate angiogenesis?
Vascular endothelial growth factors.
110
Why does necrosis often occur in the centre of a neoplasm?
The neoplasm grows quickly and outgrows its vascular supply.
111
What are the advantages of classifying neoplasms?
It helps to determine the appropriate treatment and prognosis.
112
What are the two ways in which neoplasms can be classified?
1. Behavioural classification.| 2. Histogenetic classification.
113
What is the behavioural classification of neoplasms?
Neoplasms can be classified as benign, malignant or borderline. Borderline tumours (e.g. some ovarian lesions) defy precise classification.
114
What is the histogenetic classification of neoplasms?
Histopathological tests specify tumour type by determining the cell of origin of a tumour. If the origin is unknown the tumour is said to be anaplastic.
115
What are the 7 main features of benign neoplasms.
1. Localised.2. Non-invasive.3. Slow growth, low mitotic activity.4. Close resemblance to normal tissue.5. Normal nuclei.6. Necrosis and ulceration are rare due to slow growth. 7. Exophytic growth.
116
What are the consequences of benign neoplasms?
1. Pressure on adjacent structures.2. Obstruction to flow. 3. Transformation into malignant neoplasms. 4. Anxiety.
117
What are the 7 main features of malignant neoplasms.
1. INVASIVE!2. Metastases. 3. Rapid growth, high mitotic activity. 4. Resemblance to normal tissue. 5. Poorly defined border due to invasive nature. 6. Necrosis and ulceration are common.7. Endophytic growth.
118
What are the consequences of malignant neoplasms?
Destroy surrounding tissue, blood loss due to ulceration, pain, anxiety.
119
Define carcinoma.
MALIGNANT EPITHELIAL NEOPLASM!
120
Define sarcoma.
A rare tumour of mesenchymal origin: a malignant connective tissue neoplasm.
121
What is a rhabdomyoma?
Benign striated muscle neoplasm.
122
What is an adenoma?
Benign tumour of glandular epithelium.
123
What is a papilloma?
A non-glandular benign tumour.
124
What is a leiomyoma?
A benign smooth muscle neoplasm.
125
What is a neuroma?
A benign neoplasm of nerves.
126
What is a chondrosarcoma?
A malignant neoplasm of cartilage.
127
What is a liposarcoma?
A malignant neoplasm of adipose tissue.
128
What is a melanoma?
A malignant neoplasm of melanocytes.
129
What is a lymphoma?
A malignant neoplasm of lymphoid cells.
130
What is a mesothelioma?
A malignant neoplasm of mesothelial cells.
131
Carcinomas and sarcomas are further classified according to the degree of differentiation. Is a carcinoma/sarcoma with a close resemblance to normal tissue classified as well differentiated or poorly differentiated?
A carcinoma/sarcoma with a close resemblance to normal tissue is classified as well differentiated. These types of neoplasms are low grade and have a better prognosis.
132
What must the immune system do in order to be effective?
The immune system has to discriminate self from non-self.
133
Describe innate immunity.
Non-specific, instinctive, present from birth, first line of defence. It is focused around physical and chemical barriers and phagocytosis. No lymphocyte involvement.
134
Give examples of physical and chemical barriers used in innate immunity?
Skin, mucociliary escalator, gastric acid, hairs, lysozymes etc.
135
What is the function of lysozyme?
It destroys bacterial cell walls.
136
Describe adaptive immunity.
Specific, requires lymphocytes. Memory and quicker response.
137
Give examples of 3 polymorphonuclear leukocytes.
1. Neutrophils. 2. Basophils.3. Eosinophils.
138
Give examples of 3 mononuclear leukocytes.
1. Monocytes.2. B lymphocytes. 3. T lymphocytes.
139
In which primary lymphoid tissue do T cells mature?
Thymus.
140
In which primary lymphoid tissue do B cells mature?
Bone marrow.
141
How do T cells recognise antigens?
For T cells to recognise antigens they must be displayed by an antigen presenting cell and bound to MHC1/2. T cells can't recognise soluble antigens.
142
What is the function of T helper 1 (CD4)?
It helps the immune response against intracellular pathogens. Secretes cytokines.
143
What is the function of T helper 2 (CD4)?
It helps produce antibodies against extracellular pathogens. Secretes cytokines.
144
What is the function of Cytotoxic T cell (CD8)?
It can kill cells directly by binding to antigens; they induce apoptosis.
145
What is the function of T reg (FoxP3)?
They regulate the immune response.
146
Which cells express MHC1?
All nucleated cells express MHC1. e.g. a virus infected or cancer cell would express MHC1.
147
Which cells express MHC2?
Antigen presenting cells ONLY e.g. macrophages, B cells, dendritic cells.
148
Which MHC would an intracellular antigen (endogenous) lead to the expression of?
MHC1.
149
Which MHC would an extracellular antigen (exogenous) lead to the expression of?
MHC2.
150
What type of T cell binds to MCH1?
Cytotoxic T cells (CD8).
151
What type of T cells binds to MCH2?
Helper T cells (CD4).
152
What do B cells differentiate into?
Plasma cells. The plasma cells then produce antibodies.
153
What does a helper T cell bind to?
A T cell receptor which is bound to an antigen epitope which is bound to MHC2 on an APC.
154
Which interleukin is secreted when a helper T cell is bound to a T cell receptor?
IL-2. This then binds to an IL-2 receptor on the T cell and produces a positive feedback mechanism leading to division and differentiation.
155
How many antibodies can each B cell make?
Each B cell can only make 1 antibody. This 1 antibody can only bind to 1 epitope.
156
What happens to B cells that recognise 'self'?
They are killed in bone marrow.
157
Describe the process of a T helper cell binding to a B cell.
A B-cell antibody binds an antigen -> phagocytosis -> epitope is displayed on the surface of the B-cell bound to an MHC2 -> TH2 binds to B-cells -> cytokine secretion induces B-cell clonal expansion -> differentiation into plasma cells and memory B cells.
158
Give 3 functions of antibodies.
1. Neutralise toxins. 2. Opsonisation.3. Activate classical complement system.
159
Which immunoglobulin is found in breast milk and other secretions?
IgA.
160
What are the 2 most common immunoglobulins?
IgG and IgM.
161
Which region of an antibody binds antigens?
The fab region.
162
Which region of an antibody binds to B cells?
The Fc region.
163
Name 4 types of cytokines.
1. Interferons. 2. Interleukins. 3. Colony stimulating factors. 4. Tumour necrosis factors.
164
What is the function of interferons?
Interferons produce antiviral proteins.
165
What is the function of interleukins?
Interleukins cause cell division and differentiation.
166
What is the function of colony stimulating factor (CSF)?
CSF causes division and differentiation of bone marrow stem cells.
167
What is the function of tumour necrosis factor (TNF)?
TNF mediates inflammation and cytotoxic reactions.
168
What is the function of chemokines?
Chemokines attract leukocytes to sites of infection.
169
Give examples of secondary lymphoid tissue.
The spleen, lymph nodes, mucosa associated lymphoid tissue - MALT.
170
Describe the process of phagocytosis.
1. Pathogen binds to neutrophil/macrophage.2. Engulfment of pathogen. 3. Phagosome formation.4. Lysosome fusion - phagolysosome.5. Pathogen is destroyed.
171
Give 3 examples of O2 dependent mechanisms of killing.
1. Killing using reactive oxygen intermediates.2. Superoxides can be converted to H2O2 and then to hydroxyl free radicals. 3. NO leads to vasodilation and increased extravasation and so more neutrophils etc are in the tissues to destroy pathogens.
172
What is the role of NO in killing pathogens?
NO leads to vasodilation and increased extravasation. This means more neutrophils etc pass into the tissues to destroy pathogens.
173
Why can superoxides be used to destroy pathogens?
Superoxides can be converted to H2O2 and then to hydroxyl free radicals. Hydroxyl free radicals are highly reactive and can destroy pathogens.
174
What mechanisms or cells are involved in O2 independent killing?
Defensins, lysozyme, pH, TNF.
175
Where are complement system plasma proteins derived from?
The liver.
176
What are the 3 main outcomes of complement system activation?
1. Pathogen lysis. 2. Increased phagocytosis. 3. Activation of leukocytes.
177
What activates the classical complement pathway?
Antibodies.
178
Briefly describe the classical complement pathway.
1. C1s cleaves C4 -> C4a and C4b.2. C4b binds C2b forming C4b2b. C4b2b is a C3 convertase and is responsible for C3 -> C3a and C3b. 3. C4b2b binds C3b forming C4b2b3b. 4. C5,6,7,8 and 9 also bind and eventually you get MAC formation. MAC is a pore like channel in a membrane.
179
What compound prevents excessive activation of the classical complement pathway?
C1 inhibitor.| - C1 inhibitor leads to a negative feedback loop.
180
What activates the lectin pathway?
Mannose binding protein.
181
What activates the alternative pathway?
Bacterial cell walls and endotoxin.
182
What are the 3 different pathways that make up the complement system?
1. Classical.2. Lectin. 3. Alternative.
183
Briefly describe the alternative pathway.
1. C3 reacts slowly with H2O forming C3(H2O).2. C3(H2O) binds factor B. This becomes a substrate for cleavage by factor D.3. Factor B is split into Bb and Ba. 4. Bb sticks to C3(H2O) forming C3(H2O)Bb.5. C3(H2O)Bb is a C3 convertase that cleaves C3 into C3b and C3a.6. C3b then binds to pathogens and causes opsonisation for improved phagocytosis. Also leads to MAC formation.
184
Which complement plasma proteins have opsonic properties when bound to a pathogen?
C3b and C4b.
185
What is the function of MAC in a pathogens' membrane?
MAC is a leaky pore like channel. Ions and water pass through the channel and disrupt the intracellular microbe environment -> microbe lysis.
186
Which complement plasma proteins are pro-inflammatory and cause chemotaxis and activation of neutrophils and monocytes etc?
C3a and C5a.
187
What kind of immunity are PRR's and PAMP's associated with?
Innate immunity.
188
What are PRR's a receptor for?
PAMP's.
189
Name 3 receptors that make up the PRR family.
1. Toll-like receptors (TLR).2. Nod-like receptors (NLR).3. Rig-like receptors (RLR).
190
What is the main function of TLR's?
TLR's send signals to the nucleus to secrete cytokines and interferons. These signals initiate tissue repair. Enhanced TLR signalling = improved immune response.
191
What is the main function of NLR's?
NLR's detect intracellular microbial pathogens. They release cytokines and can cause apoptosis if the cell is infected.
192
What disease could be caused by a non-functioning mutation in NOD2?
Crohn's.
193
What is the main function of RLR's?
RLR's detect intracellular double stranded RNA. This triggers interferon production and so an antiviral response.
194
TLR's are adapted to recognise damaged molecules. What characteristic do these damaged molecules often have in common?
They are often hydrophobic.
195
What kind of TLR's can be used in vaccine adjuvants?
TLR4 agonists.
196
Give examples of diseases that can be causes by PRR's failing to recognise pathogens.
1. Atherosclerosis. 2. COPD.3. Arthritis.
197
Give examples of 3 extracellular PRR.
1. Mannose receptors.2. Scavenger receptors. 3. TLR's.
198
What is the function of mannose and scavenger extracellular receptors?
The induce pathogen engulfment.
199
Give an example of an intracellular PRR.
NLR.
200
Where are circulating PRR secreted from?
Epithelia, phagocytes and the liver. They can activate the complement cascade and induce phagocytosis.
201
What happens when a PAMP binds to a PRR?
The innate immune response and inflammatory response is triggered.
202
What is extravasation?
Leukocyte (WBC) migration across the endothelium.
203
What do macrophages at the tissues secrete to initiate extravasation?
TNF alpha.
204
Describe the process of extravasation.
1. Macrophages at tissues release TNF alpha. 2. The endothelium is stimulated to express adhesion molecules and to stimulate chemokines. 3. Neutrophils bind to adhesion molecules; they roll, slow down and become stuck to the endothelium. 4. Neutrophils are activated by chemokines. 5. Neutrophils pass through the endothelium to the tissue to help fight infection.
205
What 2 compounds can act as C3 convertase?
1. C4b2b - produced in the classical and lectin pathways.| 2. C3(H2O)Bb - produced in the alternative pathway.
206
What type of cancers results from transformations in the germ line?
Inheritable cancers (<10%).
207
What type of cancers results from transformations in somatic cells?
Non-inheritable cancers (>90%).
208
What factors can cause transformations in somatic cells?
Environmental factors e.g. UV, chemicals (smoking can cause lung cancer), pathogens (HPV can cause cervical cancer).
209
What are the 7 hallmarks for cancer?
1. Evade apoptosis.2. Ignore anti-proliferative signals. 3. Growth and self sufficiency. 4. Limitless replication potential.5. Sustained angiogenesis. 6. Invade surrounding tissues.7. Escape immuno-surveillance.
210
What are the two types of tumour antigens and where are they found?
1. Tumour specific antigens; only found on tumour cells. Due to point mutations. 2. Tumour associated antigens; found on normal cells and over expressed on tumour cells.
211
What is cancer immunosurveillance?
When the immune system recognises and destroys transformed cells, this is an important host protection process.
212
What is cancer immunoediting?
When the immune system kills tumour cells changes are induced in the tumour, the tumour cells are 'edited' by natural selection. The tumour cells are then disguised from the immune system, they escape destruction and recurrence is possible.
213
What are the 3 E's of cancer immunoediting?
1. Elimination.2. Equilibrium.3. Escape.
214
Give an example of active cancer immunotherapy.
Vaccination e.g. killed tumour vaccine, purified tumour antigens, APC-based vaccines etc.
215
Give an example of passive cancer immunotherapy.
T cell transfer, anti-tumour antibodies.
216
Why is hypoxia a prominent feature of a lot of malignant tumours?
Malignant tumours grow rapidly and so outgrow their blood supply.
217
Give 3 reasons why hypoxic tumours have a poor prognosis for the patient.
1. Hypoxic tumours have growth factors for angiogenesis and so can receive nutrients for growth. 2. They suppress the immune system.3. They are resistant to chemotherapy and radiotherapy.
218
Give 3 advantages of active immunity.
1. Induces immunological memory.2. Produces high affinity antibodies.3. It produces a persistent protective response against pathogens.
219
Give 2 advantages of passive immunity.
1. Immediate effect.| 2. Useful treatment for acute dangers e.g. snake venom.
220
Give 3 disadvantages of passive immunity.
1. Short term.2. No immunological memory produced.3. Reaction is possible.
221
Describe the first immune response to initial exposure.
1. Innate immune response. 2. IgM predominates. 3. Low affinity.
222
Describe the second immune response following exposure to a pathogen encountered before.
1. Rapid and larger than the first.2. High affinity IgG.3. Adaptive immunity, T cell help.
223
Give 3 advantages of live vaccines.
1. Very effective, prolonged and comprehensive. 2. Immunological memory produced. 3. Often only 1 vaccine is needed.
224
Give 2 disadvantages of live vaccines.
1. Immunocompromised patients may become ill.| 2. Vaccines often need to be refrigerated which can be a problem in remote areas.
225
Give 2 advantages of inactivated vaccines.
1. There is no risk of infection.| 2. Storage is less critical.
226
Give 3 disadvantages of inactivated vaccines.
1. Inactivated vaccines tend to only activate the humoral response; there is a lack of T cell involvement. 2. The response is often weak.3. Boosters are needed and so patient compliance may be poor.
227
What is the role of an adjuvant?
An adjuvant is a substance added to a vaccination to stimulate an immune response. They convince your immune system that you're infected.
228
What can be used as an adjuvant?
Toxoids, proteins, chemicals (aluminium salts) etc.
229
What are the 5 features of an ideal vaccine?
1. Safe.2. Induces a suitable immune response.3. Shouldn't require repeated boosters.4. Generates immunological memory.5. Stable and easy to transport.
230
Give 3 advantages of transplantation.
1. Improved quality of life. 2. Improves survival rates. 3. Cost effective.
231
Why are immunosuppressive agents needed to prevent rejection?
Transplanted organs are recognised as non self and therefore are seen as a threat. Graft v host disease; T-cells destroy graft cells.
232
On which chromosome are MHC proteins found?
Chromosome 6.
233
Describe the transplant cascade.
Donor -> organ preservation -> implantation -> re-perfusion -> organ function.
234
What are the main compounds involved in reperfusion injury?
Free radicals e.g. H2O2, O2-, OH-. They damage cell walls.
235
Define allorecognition.
The ability of an organism to distinguish its own tissues from those of another. Recognition of non-self antigens.
236
What are the consequences of transplant rejection?
Fibrosis and scarring.
237
Describe the immune responses to detection of graft antigens.
1. Innate immune response is activated. 2. T cell mediated cytotoxicity.3. Ab mediated cytotoxicity. 4. Hypersensitivity. 5. Tolerance.
238
Give 6 ways of preventing transplant rejection?
1. Manage risk factors. 2. Tissue typing. 3. Cross match. 4. Immunosuppressive agents.5. Sensitisation and desensitisation. 6. Tolerance.
239
Why is it important to get the balance right when using immunosuppressive agents?
Too much = infection.| Too little = rejection.
240
What is involved in tissue typing?
1. Blood group matching.| 2. HLA typing.
241
What is involved in cross matching?
Detecting anti HLA antibodies.| Cell based assays and solid phase assays can be used.
242
Define tolerance with regards to transplant immunology.
Tolerance is the acquired modification to host immunity leading to drug free transplant survival with full immunocompetence.
243
Define xenotransplantation.
Transplantation of tissues from one species to another.
244
What is allergy?
An abnormal response to harmless foreign material.
245
What is atopy?
The tendency to develop allergies.
246
Which immunoglobulin is most commonly involved in allergic responses?
IgE.
247
Which cells are most commonly involved in allergic responses?
Mast cells! Also eosinophils and basophils.
248
What happens to IgE receptors when a 'threat' is identified?
The receptors cross-link.
249
Which cells express high affinity IgE receptors?
Mast cells, basophils and eosinophils.
250
What are the steps in an allergic response?
Allergen/threat is identified -> high affinity IgE receptors cross link -> IgE binds -> Mast cells are activated -> granules released -> histamine and cytokines. Cytokines induce a TH2 response.
251
What is the main IgE receptor cell?
MAST CELLS!
252
Which compound causes blood vessel dilation and vascular leakage in an allergic response?
Histamine.
253
What is the role of cytokine release in an allergic response?
They induce a TH2 response.
254
Which cells and which immunoglobulin is commonly involved in anaphylaxis?
- Mast cells and basophils.| - IgE.
255
Give examples of anaphylactic systemic effects.
- CV: vasodilation, lowered BP.- Resp: bronchial SM contraction, mucus.- Skin: rash, swelling. - GI: pain, vomiting.
256
Give 5 possible treatments for allergy and hypersensitivity.
1. Avoid allergens.2. Desensitisation (immunotherapy, some risks).3. Prevent IgE production (interfere with TH2 pathway).4. Prevent mast cell activation.5. Inhibit mast cell products (e.g. histamine receptor antagonists).
257
Which infection is most often seen in patients with hypogammaglobulinemia?
Streptococcus penumonia sinusitis.
258
Give 5 examples of PAMPs.
1. Lipopolysaccharides. 2. Endotoxins.3. Bacterial flagellin.4. Peptidoglycans.5. dsRNA.
259
Which PRR responds to lipopolysaccharides?
TLRs.
260
Is production of interferons (anti-viral proteins) part of the elimination phase of complement activation?
No
261
Give 4 causes of acquired immunodeficiency.
1. Cancer.2. HIV.3. Having chemotherapy.4. Taking immunosuppressants.
262
What signs and symptoms might a person with HIV present with?
Fever, weight loss, recurrent infections, respiratory infections, TB.
263
What immune system cells are affected in HIV?
There is CD4 deficiency and B cell defects too. The adaptive immunity is affected.
264
What is the name of the disease that is characterised by B cell deficiency?
Hypogammaglobulinaemia.
265
What infection is most commonly seen in patients with hypogammaglobulinaemia?
Streptococcus pneumonia.
266
Describe hyper IgM syndrome.
High numbers of IgM. IgM is non specific and has a low affinity. IgM is unable to class switch to more 'useful' immunoglobulins and so IgA, IgE and IgG numbers are low.
267
What are the consequences of complement deficiency?
Impaired opsonisation of encapsulated bacteria.
268
What is terminal complement deficiency and what are its consequences?
- Terminal complement deficiency is when there's a problem with C5-8 and so MAC isn't produced. - The consequences of this are chronic Neisserial infections and recurrent meningitis.
269
What are the consequences of being deficient in C1 inhibitor?
Angioedema - facial swelling.
270
What are the consequences of being deficient in C1, 2 or 4?
Increased likelihood of autoimmune disease especially systemic lupus erythematosus.
271
What are the consequences of hyposplenism?
Reticuloendothelial function is decreased. This means the body has difficulty dealing with encapsulated bacteria e.g. streptococcus pneumonia.
272
What is thymic aplasia?
A deficiency in mature T cells.
273
How can immune function be assessed?
1. Looking at neutrophil numbers, morphology and flow cytometry.2. Looking at B and T cell subsets, numbers and response to vaccines.3. Genetic studies.
274
Give 3 examples of chronic inflammatory diseases.
1. Rheumatoid arthritis.2. Crohn's disease.3. TB.
275
Name 3 conventional therapies used in managing CID.
1. NSAIDs.2. DMARDs.3. Steroids.
276
What disease are DMARDs most commonly used in the management of?
Rheumatoid arthritis.| DMARD - disease-modifying antirheumatic drug
277
How do NSAIDs work in relieving inflammation.
NSAIDs inhibit COX 1 and 2. COX 2 is needed for prostaglandin synthesis. Prostaglandins are responsible for inflammation and pain. Therefore NSAIDs reduce symptoms of inflammation and pain.
278
What is a disadvantage of long term NSAID use?
NSAIDs can cause gastric bleeding. They inhibit COX 1 which is needed for prostaglandin synthesis and prostaglandins are needed for gastric mucus production.
279
Give 2 advantages of biological agents in treating chronic inflammatory disease?
1. They're extremely specific.| 2. A low dose is very effective.
280
Give 5 disadvantages of biological agents in treating chronic inflammatory disease?
1. They're very expensive.2. There is a risk of contamination. 3. They're always injected.4. They're immunosuppressive. 5. They need to be handled carefully to prevent denaturation.
281
What class of biological agent is often used in the treatment of rheumatoid arthritis when DMARDs fail?
TNF blockers - they bind to TNF to prevent it interacting with its receptors.
282
Name 3 TNF blockers.
1. Etanercept (TNF alpha specific).2. Infliximab.3. Adalimumab.
283
What compound is often combined with biological agents to make treatment cheaper?
Methotrexate.
284
Give a side effect of using TNF blockers.
Increased susceptibility to TB.
285
How do IL-6 blockers work?
IL-6 is an inflammatory cytokine. The biological agent binds to IL-6 so as to prevent it interacting with its receptor.
286
Name an IL-6 blocker.
Tocilizumab.
287
When are IL-6 blockers used?
They're used in the treatment of rheumatoid arthritis when TNF blockers fail.
288
What are the risks of using IL-6 blockers?
They dampen the immune response and so you have an increased risk of infection. There is also an incerased risk of shingles and chickenpox.
289
Name 4 classes of biological agents and give an example of a drug for each.
1. TNF blockers e.g. etanercept.2. IL-6 blockers e.g. Tocilizumab.3. Anti B lymphocytes e.g. rituximab.4. T cell activation blockers e.g. abatacept.
290
In what region of the antibody is there reversible bonding between antibodies and antigens?
Complementarity determining region (CDR).| - Hydrogen bonds and VDW's etc form cumulative weak interactions that together form a strong force.
291
True or False. The heavy and light chains of an antibody are coded for by the same gene.
False. Distinct sets of genes code for the heavy and light chains.
292
What region determines Ig class?
The constant region!
293
What is the result of recombination in the Ig region?
Class switching.
294
Describe complement fixation.
An antibody binds multiple antigens so as to bring the Fc regions together. The complement pathway is initiated in this process and you get MAC formation.
295
Which compound is responsible for signalling when an antigen binds to an antibody?
Tyrosine kinase.
296
What immunoglobulin do naive antibodies express?
IgM.
297
Describe the process of class switching.
Antigen engagement and T cell help will result in class switching. A different FC region is used and there is affinity maturation.
298
What do T cells recognise?
PEPTIDES
299
Describe somatic hypermutation.
1. Random mutations in CDR.2. Amino acid sequences are effected meaning Ab-Ag affinity is altered. 3. High affinity B cell clones are selected via natural selection.
300
Briefly describe the steps involved between T cell stimulation and plasma cell differentiation.
1. T cells are stimulated.2. Cytokine release. 3. B cell proliferation. 4. Somatic hypermutation. 5. High affinity B cell clones differentiate into plasma cells and memory cells.
301
Give 4 uses of antibodies in medicine.
1. Diagnostic tools. 2. Immunoassays, Ab's are used to measure the presence of a molecule. 3. Flow cytometry, Ab's label cells in suspension. 4. Therapeutic uses, monoclonal Ab's can act as specific antagonists for biological targets e.g. HERCEPTIN.
302
Give an example of a proton pump inhibitor.
Omeprazole.
303
Give an example of a statin.
Simvastatin.
304
Give an example of an ACE inhibitor.
Enalapril.
305
Give an example of a COX inhibitor.
Aspirin and paracetamol.
306
Give an example of a β2 adrenoceptor agonist.
Salbutamol.
307
Give an example of a β1 adrenoceptor blocker.
Atenolol.
308
Give an example of a Ca2+ channel blocker.
Amlodipine.
309
Give an example of a broad spectrum antibiotic.
Amoxicillin.
310
Give an example of an opiate analgesic.
Tramadol.
311
What do most drugs target?
Proteins!
312
Name 4 receptors that drugs target.
1. Ligand gated ion channels. 2. GPCR.3. Kinase linked.4. Cytosolic/nuclear.
313
Give an example of a ligand gated ion channel.
Nicotinic Ach receptor.
314
Give an example of a GPCR.
Muscarinic and β2 adrenoceptor.| GPCR's usually interact with adenylate cyclase or phospholipase C
315
Give an example of a kinase linked receptor.
Receptors for growth factors.
316
Give an example of a cytosolic/nuclear receptor.
Steroid receptors; steroids affect transcription.
317
What are agonists?
Agonists bind to a receptor and to activate it.
318
What are antagonists?
Antagonists decrease the effect of an agonist. They show no response at a receptor.
319
Describe the shape of a log dose-response curve.
Sigmoidal.
320
What does EC50 tell us about a drug?
Its potency!
321
What is EC50?
The concentration of drug that gives half the maximal response.
322
Would a drug with a lower EC50 have a lower or greater potency?
Greater potency.
323
What does Emax tell us about a drug?
Efficacy.
324
Which is more efficacious, a full agonist or partial agonist?
A full agonist is more efficacious because a full agonist can give a 100% response.
325
Would an antagonist shift a dose-response curve to the left or right?
The antagonist would shift the dose-response curve to the RHS. The drug therefore becomes less potent.
326
Drug action: define affinity.
How well a ligand binds to a receptor.
327
Drug action: define efficacy.
How well a ligand activates a receptor; how well it induces a conformational change.
328
What is the effect of fewer receptors on drug potency?
Fewer receptors will shift the dose-response curve to the RHS, this means drug potency will be reduced.
329
What is the effect of fewer receptors on receptor response?
Receptor response is still 100% due to receptor reserve. (Partial agonists don't have receptor reserve).
330
What is the affect of less signal amplification on drug response?
Less signal amplification gives a reduced drug response.
331
Describe allosteric modulation.
An allosteric modulator binds to a different site on a receptor and influences the role of an agonist.
332
What is inverse agonism?
Where an agonist has a negative effect at a receptor.
333
Does an antagonist show efficacy?
No. An antagonist has affinity but zero efficacy. An agonist however demonstrates affinity and efficacy.
334
Pharmacology: define tolerance.
A reduction in the effect of a drug overtime. This can be due to continuous use of repeatedly high concentrations.
335
What 3 ways can a receptor be desensitised?
1. Uncoupled (an agonist would be unable to interact with a GPCR).2. Internalised (endocytosis, the receptor is taken into vesicles in the cell).3. Degraded.
336
Can aspirin be described as a selective drug?
No. Aspirin is non-selective, it acts on COX1 and COX2.
337
What is the function of COX1 and COX2?
They cyclise and oxygenate arachidonic acid and produce prostaglandin H2.
338
What does prostaglandin H2 form when it interacts with synthases?
Prostanoids.
339
Define pro-drugs and give an example of one.
Drugs that need to be activated enzymatically e.g. ACE inhibitors, enalapril.
340
How do ACE inhibitors work?
Angiotensinogen is converted to angiotensin 1 via renin. Angiotensin 1 is then converted to angiotensin 2 via ACE. ACE inhibitors prevents angiotensin 1 binding and so you don't get angiotensin 2 formation. (Angiotensin 2 is a vasoconstrictor and so ACEi can be used in the treatment of hypertension).
341
Give an example of a β lactam antibiotic.
Penicillin and amoxicillin.
342
How do β lactam antibiotics work?
The inhibit transpeptidase and so prevent bacterial cell wall synthesis.
343
How do diuretics work?
They inhibit 'synporters' in the loop of henle. This leads to increased H2O excretion and decreased salt reabsorption and so BP decreases.
344
Give an example of loop of henle diuretics.
- Furosemide, act on the ascending loop.| - Thiazides, act on the distal tubule.
345
How can drugs be developed?
1. Serendipity, by chance. e.g. penicillin.| 2. Rational drug design. e.g. propranolol.
346
Describe how rational drug design works.
Rational drug design is focused on developing an antagonist from an agonist. It looks at solubility, electrostatic charge and bulk.
347
How do you determine whether insulin is long or short acting?
Small changes in amino acid sequence will determine whether insulin is long or short lasting - RECOMBINANT PROTEIN!
348
Name 3 things that the chemical properties of a drug can influence?
1. Administration. 2. Distribution.3. Elimination.
349
As the difference in concentration falls what happens to the rate of reaction?
The rate of reaction will slow down.| Rate is proportional to the concentration of drug
350
What is the association between diffusion and concentration gradient?
Diffusion is proportional to concentration gradient; this is a first order process and represents an exponential function.
351
How many litres of water are there in the following body compartments: a) Plasma.b) Interstitial space.c) Intracellular space.
a) 3L.b) 11L.c) 28L.
352
What are the 5 ways by which fluid can move between compartments?
1. Simple diffusion.2. Facilitated diffusion. 3. Active transport.4. Movement through extra-cellular spaces.5. Non-ionic diffusion.
353
What can influence the degree of ionisation of weak acids and weak bases?
pH.
354
What equation can be used to determine the degree of ionisation at a specific pH?
Henderson Hasselbach.| pH = log[A-]/[HA] + pKa.
355
What can enhance non ionic diffusion?
Non ionic diffusion can be enhanced if adjacent compartments have pH difference.
356
In terms of ionisation, what happens to Aspirin in the stomach?
Aspirin is a weak acid and so becomes less ionised in the stomach due to the low gastric pH.
357
What is the advantage of aspirin becoming less ionised in the stomach?
This allows rapid non-ionic diffusion across the gut membrane into the plasma. Once in the plasma aspirin becomes more ionised again.
358
What is the effect of an increase in pH on a weak acid?
The weak acid will become more ionised.
359
What is the effect of an increase in pH on a weak base?
The weak base will become less ionised.
360
What is the effect of a decrease in pH on a weak acid?
The weak acid will become less ionised.
361
What is the effect of a decrease in pH on a weak base?
The weak base will become more ionised.
362
Define bioavailability.
The amount of drug taken up as a proportion of the amount administered. It is a reflection of uptake.
363
What route of drug administration has a bioavailability of 1?
IV infusion, all the drug administered will go into the plasma.
364
Explain what would happen to the bioavailability of aspirin if gastric pH increased.
The bioavailability would decrease. Aspirin would be more ionised and so wouldn't diffuse across the gut into the plasma as rapidly this would mean aspirin uptake would decrease.
365
Give 2 factors that drug distribution in the plasma depends upon.
1. Chemical properties.| 2. Molecular size.
366
Write an equation for the volume of distribution (Vd).
Vd = amount of drug administered/concentration of drug in plasma.
367
If a drug had a high Vd what would that tell us about the drug?
This would indicate that the drug was highly lipid soluble and that most of the drug had moved into the intracellular space, less was in the plasma.
368
What is the relationship between plasma concentration and Vd?
Plasma concentration is inversely proportional to Vd.
369
Give 3 factors that can increase gastric pH.
1. Ingesting alkaline foods.2. Antacids.3. Omeprazole (PPI).
370
Give the two definitions for clearance.
1. The volume of plasma from which a drug is completely removed per unit time. 2. The rate at which plasma drug is eliminated per unit plasma concentration.
371
Write an equation for renal clearance.
Renal clearance = Rate of appearance in urine / plasma concentration.
372
What are the two ways by which drugs can be eliminated in the kidneys?
1. Glomerular filtration.| 2. Active secretion.
373
What are the possible dangers of kidney damage with regards to renal clearance?
Kidney damage results in decreased renal clearance and so there is danger of accumulation, over dosage and toxicity.
374
What compound do many lipid soluble drugs combine with to increase their hydrophilicity?
Glucuronic acid.
375
Define hepatic extraction ratio (HER).
The proportion of a drug removed by one passage through the liver.
376
What is the limiting factor when a drug has a high HER?
Hepatic blood flow, perfusion limited.
377
What is the limiting factor when a drug has a low HER?
Diffusion limited. A low HER is slow and not efficient.
378
What happens to high and low HER drugs when enzyme induction is increased?
The clearance of low HER drugs increases. There is minimal effect on high HER drugs.
379
Where do phase 1 hepatic metabolism reactions occur?
In the smooth endoplasmic reticulum.
380
What enzyme usually catalyses phase 1 reactions?
CYP450.
381
What is a phase 2 hepatic metabolism reaction?
Phase 2 reactions involve conjugation and glucuronidation etc. They usually inactivate products and increase hydrophilicity for renal excretion.
382
Give 3 advantages of IV infusion.
1. Steady state plasma levels are maintained. 2. Highly accurate drug delivery.3. IV infusion can be used for drugs that would be ineffective when administered via an alternative route.
383
Give 3 disadvantages of IV infusion.
1. Expensive.2. Needs constant checking. 3. Calculation error likely.
384
Give an advantage of a drug having a low Vd.
It is easy to reach steady state and plasma concentration is ‘responsive’ to dose rate.
385
Give 4 properties of the 'ideal drug'.
1. Small Vd.2. Drug broken down effectively by enzymes. 3. Predictable dose:response relationship.4. Low risk of toxicity.
386
What are the advantages of pulsatile secretion as opposed to steady state?
1. Enhanced responsiveness.| 2. More information can be conveyed.
387
What is the principal neurotransmitter in the body?
Acetylcholine.
388
What receptor does Ach interact with in the somatic nervous system?
Post-synaptic nicotinic receptors at the neuromuscular junction.
389
What type of receptor are nicotinic receptors?
Ligand gated ion channels.
390
Briefly describe how Ach is synthesised.
Acetyl CoA, choline and choline acetyl trasnferase combine to form acetylcholine. Ach is taken up into a vesicle in the presynpatic cleft and will be released following Ca2+ influx.
391
What enzyme is responsible for acetylcholine breakdown in the synaptic cleft?
Acetylcholinesterase.
392
Describe the action of botulinum toxin at the NMJ,
Botulinum toxin inhibits Ach release at the NMJ. Protease degrade vesicle proteins.
393
Describe the action of competitive antagonists at the NMJ.
They block Ach receptors. Competitive antagonists are muscle relaxants, adjuncts to general anaesthesia.
394
Describe the action of depolarising agonists (blockers) at the NMJ.
Depolarising agonists cause receptor desensitisation.
395
Describe the action of anticholinesterases at the NMJ.
There is increased Ach in the synaptic cleft. Ach can then compete with depolarising blockers.
396
What type of receptor are muscarinic receptors?
GPCR.
397
Give examples of adverse muscarinic agonist effects.
1. Diarrhoea.2. Urination.3. Miosis.4. Brachycardia. 5. Emesis (vomiting).6. Lacrimation. 7. Salivation.
398
Give 2 examples of Ach action in the CNS.
1. Motion sickness; Ach stimulates the vomiting centre in the brain.2. Ach leads to increase dopamine re-uptake and so can worsen the symptoms of Parkinson's.
399
Briefly describe catecholamine synthesis.
Tyrosine -> L-DOPA -> Dopamine -> Noradrenaline -> Adrenaline.
400
Where does the conversion from Dopamine to Noradrenaline happen?
In a vesicle in the pre-synpatic neurone.
401
Which enzymes inactivate catecholamines?
MAO and COMPT.
402
Which protein does α1 interact with to activate phospholipase C?
Gq.
403
What is the primary function of α1?
α1 leads to vasoconstriction.
404
Which protein does α2 interact with in order to inhibit adenylate cyclase synthesis?
Gi.
405
What is the primary function of α2?
α2 is responsible for pre-synaptic inhibition; it inhibits NAd release.
406
What protein does β1,2,3 interact with in order to activate adenylate cyclase?
Gs.
407
What is the role of adenylate cyclase?
It converts ATP to cyclic AMP, this then leads to PKA synthesis.
408
What are the primary functions of β1?
1. Increased cardiac effects e.g. force, rate and conduction. 2. Increased renin secretion.
409
What are the primary functions of β2?
1. Bronchodilation.| 2. Vasodilation.
410
What are the primary functions of β3?
1. Increase lipolysis.| 2. Bladder relaxation.
411
What would an α1 adrenergic antagonist do?
1. Vasodilation.| 2. Relaxation of bladder neck = reduced resistance to bladder outflow.
412
What disease could an α1 adrenergic antagonist be used in the treatment of?
Benign prostatic hyperplasia.
413
What would a β1 adrenergic antagonist do?
1. Reduce CO.| 2. Reduce renin secretion.
414
What diseases could an β1 adrenergic antagonist be used in the treatment of?
Hypertension, angina and arrhythmia.
415
Define pain.
An unpleasant sensory and emotional experience associated with actual or potential tissue damage.
416
Give 3 advantages of pain.
1. Gives a warning for tissue damage.2. Immobilisation for healing.3. Memory establishment.
417
Define acute pain.
Pain caused by nociceptor activation. It is of short duration,
418
Define chronic pain.
Pain that is on-going or persistent, it lasts for >3-6 months.
419
Define neuropathic pain.
Pain caused by a primary lesion or dysfunction of the nervous system.
420
Define nociceptive pain.
Pain caused by actual or potential damage to non neural tissue, it is due to nociceptor activation.
421
Are A delta fibres myelinated or unmyelinated?
Myelinated.
422
Are C fibres myelinated or unmyelinated?
Unmyelinated.
423
Describe the type of pain that A delta fibres conveys.
Quick, sharp, localised.
424
Describe the type of pain that C fibres conveys.
Slow, dull, spread out.
425
Describe pain wind up.
A perceived increase in pain intensity over time when a stimulus is repeatedly delivered. It is caused by C fibre stimulation.
426
Describe the gate control theory.
Non-noxious stimuli trigger larger A beta fibres, these override smaller pain fibres and 'close the gate' to pain transmissions to the CNS.
427
What is pain treatment focused on?
1. Reducing excitatory neurotransmitters and nerve excitation. 2. Enhancing inhibitory neurones.
428
What are released in the presence of pain?
Endorphines.
429
What is an adverse drug reaction?
A noxious and unintended response to a drug.
430
Rawlins-Thompson system: Describe a type A adverse drug reaction.
- Augmented. - Very common. - Predictable from physiological effects of the drug. - Often dose related.
431
Rawlins-Thompson system: Describe a type B adverse drug reaction.
- Bizarre. - Unpredictable. - Immunological mechanisms and hypersensitivity. - Often there is a history of allergy.
432
Rawlins-Thompson system: Describe a type C adverse drug reaction.
- Chronic.| - Occurs after long term therapy.
433
Rawlins-Thompson system: Describe a type D adverse drug reaction.
- Delayed.| - Occurs many years after treatment.
434
Rawlins-Thompson system: Describe a type E adverse drug reaction.
- End of use.| - Withdrawal reaction after long term use; complications of stopping medication.
435
What is the treatment for a type A adverse drug reaction?
Reduce the dose.
436
What is the treatment for a type B adverse drug reaction?
Withdraw drug immediately!
437
Describe type 1 hypersensitivity.
IgE mediated hypersensitivity. Acute anaphylaxis. IgE becomes attached to mast cells, IgE cross linking leads to mast cell degranulation -> histamine.
438
Describe type 2 hypersensitivity.
IgG mediated cytotoxicity.
439
Describe type 3 hypersensitivity.
Immune complex deposition; immune complexes have not been adequately cleared by innate immune cells, giving rise to an inflammatory response.
440
Describe type 4 hypersensitivity.
T cell mediated.
441
Give 6 features of anaphylaxis.
1. Rapid onset. 2. Blotchy rash. 3. Swelling of face and lips.4. Wheeze. 5. Hypotension. 6. Cardiac arrest if severe.
442
What can cause a type 1 hypersensitivity reaction?
Pollen, cat hairs, peanuts etc. (allergies).
443
What can cause a type 2 hypersensitivity reaction?
Transplant rejection.
444
What can cause a type 3 hypersensitivity reaction?
Fungal.
445
What can cause a type 4 hypersensitivity reaction?
TB.
446
What is the treatment for anaphylaxis?
1. Commence basic life support (ABC).2. Stop infusion of drug. 3. Give adrenaline and anti-histamines.
447
Give 4 risk factors for hypersensitivity.
1. Protein based macromolecules.2. Female > male.3. Immunosuppression. 4. Genetic factors.
448
Why are drug interactions such a big problem today?
1. Ageing population. 2. Polypharmacy.3. Increased use of over the counter drugs.
449
Give 5 patient risk factors for drug interactions.
1. Old age.2. Polypharmacy.3. Renal disease.4. Hepatic disease. 5. Genetics.
450
Give 3 drug related risk factors for drug interactions.
1. Narrow therapeutic index. 2. Steep dose/response curve.3. Saturable metabolism.
451
Name 3 types of drug interaction.
1. Synergy; interaction of 2 compounds leads to a greater combined effect. 2. Antagonism; one drug blocks another.3. Other.
452
How might drug interactions affect drug metabolism?
If a drug inhibits or induces CYP450 it might affect the metabolism of another drug.
453
How does avocado affect CYP450? And what drug might this impact on?
Avocado is a CYP450 inductor. Warfarin is likely to be affected and the risk of blood clots will be increased.
454
How does grapefruit juice affect CYP450? And what drugs might this impact on?
Grapefruit juice is a CYP450 inhibitor, it affects CYP3A4 specifically and increases the bioavailability of some drugs e.g. Ca2+ channel blockers and immunosuppressants.
455
Are weak acids cleared quicker if urine is more acidic or more alkali?
Weak acids are cleared quicker if urine is more alkali.
456
Are weak bases cleared quicker if urine is more acidic or more alkali?
Weak bases are cleared quicker if urine is more acidic.
457
What drug acts as an antagonist at the μ receptor?
Naloxone.
458
What enzyme is needed to metabolise codeine?
Codeine is a pro drug and needs to be metabolised by CYP2D6.
459
What is the bioavailability of morphine taken orally?
50%.
460
10mg of morphine is taken orally. What is the equivalent dose if given parenterally?
5mg.
461
What is morphine metabolised to?
Morphine 6 glucuronide.
462
Where might μ receptors be found?
In the epidural space and CSF.
463
Give 5 side effects of opioid use.
1. Respiratory depression. 2. Sedation. 3. Nausea. 4. Vomiting. 5. Constipation.
464
Describe the dose-response curve for morphine.
As dose increases response increases. This association is initially rapidly and then the graph plateaus. It is not sigmoidal!
465
Name a protein that can inhibit apoptosis.
BCL-2; it inhibits pro-apoptotic proteins e.g. caspase and therefore inhibits apoptosis.
466
What disease might develop in someone with a non-functional BCL-2 protein?
Cancer.
467
Where are mast cells found?
They are only found in tissues, not in the blood!
468
What is dobutamine used in the treatment of and at what receptor is it an agonist?
Dobutamine is a beta 1 agonist. It is used in the treatment of heart failure.
469
Define physiological antagonism.
A substance that produces effects that counteract the effects of another substance.
470
What are the 3 actions of NSAIDS?
1. Anti-inflammatory.2. Analgesic.3. Anti-pyrexic.(AAA).
471
Name a local anaesthetic.
Lidocaine.
472
How do local anaesthetics work?
They inhibit pain by stopping impulse conduction in sensory nerves.
473
What drug inhibits ACh release at the NMJ?
Botulinum toxin.| It is used to treat urinary incontinence and also cosmetically as a muscle relaxant.
474
Give 3 cytokines secreted by TH2.
1. IL-4.2. IL-6.3. IL-13.4. IL-5.5. IL-10.
475
What is the name of the variable region on an antibody?
Fab region.
476
Name 3 cytokines secreted by TH1.
1. IL-2.2. Gamma-interferon.3. TNF-beta.
477
Name 2 cytokines secreted by TREG.
1. IL-10.| 2. TGF-beta.
478
Define adenocarcinoma.
A malignant tumour of glandular epithelium.
