Ischaemia PPQ Flashcards
A 12 month old baby is found to be producing insufficient amounts of factor VIII to mediate blood clotting.
Which step in the clotting process is deficient in this case?
Activation of factor IX Activation of factor V Activation of factor X Conversion of fibrinogen to fibrin Conversion of prothrombin to thrombin
Activation of factor X
Explanation:
Last step of the intrinsic pathway. Factor VIIIa is a cofactor IXa, converts factor X to the active form factor Xa. In the inactive form
Factor VIII is bound to von Willebrand factor. When injury occurs Factor VIII is activated to VIIa and von Willebrand dissociates from the complex.
Myocardial infarction (MI) is associated with cardiomyocyte death resulting from interrupted blood flow and lack of oxygen supply to the heart muscle. The degree of damage resulting from MI can be determined by measuring the concentration of cardiac markers. Which of the following is the most appropriate marker cardiac injury?
AST aspartate transaminase Creatinine kinase CK Lactate dehydrogenase LDH Myoglobin MB Troponin I (Tnl)
Troponin I (Tnl) Explanation: Myoglobin & LDH are not specific for cardiac injury and can be seen in skeletal muscle damage. The troponin I antibody used in the immunoassay is specific for the cardiac isoform of TnI and is therefore specific to myocardial injury. Skeletal and cardiac isoforms of TnI are expressed from separate genes and although they share sequence identity and are homologous (derived from a common ancestor) have distinct regions (e.g. the unique 30 amino acid N-terminal extension in cTnI) that enable specific antibodies to be raised against these epitopes.
Low oxygenation levels within a tumour environment promote the activity of hypoxia-inducible factor-1 (HIF-1) which leads to the formation of new blood vessels and allows tumour cells to receive nutrients and oxygen. What mechanism prevents this process from a occurring under normoxic conditions?
Binding of an inhibitor molecule to HIF-1
Dephosphorylation of HIF-1
Steric hindrance of HIF-1 nuclear translocation
Lack of of transcription of HIF-1
Ubiquination & proteasomal degradation of HIF-1
Ubiquination & proteasomal degradation of HIF-1
In normoxic conditions, angiogenesis and erythropoiesis are inhibited by the enzymatic modification of amino acid residues within the alpha subunit of HIF, which determines whether or not the protein is degraded. Which type of enzyme carries out this oxygen-sensing function? A Caspase B GTPase C Hydroxylase D Serine/threonine kinase
C
Hydroxylase
Prolyl hydroxylases hydroxylate (add an OH group) to HIF-1α in normoxia (normal oxygen concentrations).
Ubiquitination is a protein post-translational modification process that attaches ubiquitin to a protein. This process plays an important role in the HIF pathway by marking HIF- 1α for degradation.What is ubiquitin?
A Amino acid B Inorganic chemical C Metal ion D Protein E Sugar moiety
D
Protein
A 58 year old man is to undergo percutaneous transluminal coronary angioplasty (PTCA) following a myocardial infarction. His cardiologist tells him that he intends to insert a drug-eluting stent as part of the angioplasty procedure, and explains that the device will release a drug to reduce the chance of the blood vessel narrowing again after the procedure.
What type of drug would be most appropriate for this purpose?
ANSWER CHOICE
Anti-platelet drug Anti-platelet drug Beta blocker Immunosuppressant drug Statin Thrombolytic drug
Immunosuppressant drug
Explanation:
Prevents restenosis by inhibiting expression of specific cytokines involved in smooth muscle cell proliferation. Stopping SM cell proliferation in the tunica media of the stented blood vessel wall prevents collagen formation in the intima and formation of a new plaque.
Almost every cell, in almost every tissue of a vertebrate, is located within 50-100μm of a blood capillary. When there is lack of adequate blood supply to any cell, there is stimulation of angiogenesis to restore the blood supply.
Lack of which substance or cell is the main stimulus for this process?
erythropoietin
free fatty acids
glucose
oxygen
white blood cell
oxygen 02
Explanation:
Angiogenesis occurs after gene expression resulting from the binding of the HIF complex to the Hypoxia response elements of DNA.
Neuronal excitotoxicity is a process that contributes to neuronal cell death in diverse cerebral pathologies, including stroke, multiple sclerosis and Alzheimer’s Disease.
Which receptor may be stimulated to elicit this process?
Beta adrenoreceptor
D2 dopamine receptor
Muscarinic acetylcholine receptor
Nicotinic acetylcholine receptor
NMDA receptor
NMDA receptor
Ischaemic stroke occurs when blood flow to the brain is obstructed. The current treatment for ischaemic stroke is tissue plasminogen activator (tPA), which is most effective if administered within 3 hours of the onset of symptoms.
How does this treatment exert its protective effects in ischaemic stroke?
Prevention of blood clot formation Prevention of leukocyte activation Promotion of blood clot breakdown Promotion of neuronal regeneration Prevention of apoptotic cell death
Promotion of blood clot breakdown
An acute rise in intracranial pressure can result from a number of clinical conditions such as acute head injury, hydrocephalus (a build-up of fluid in the cavities of the brain), or stroke. The increased intracranial pressure pushes the cerebellar tonsils into the foramen magnum and consequently increases pressure on the medulla oblongata.
What would be the major physiological consequence of this?
Blurred vision
Depression of breathing
Difficulty speaking
Inability to concentrate
Personality changes
Depression of breathing
A patient is describing how his partial (focal) epileptic seizures are experienced. He says: “I lose my ability to speak - it’s weird, I know what I want to say but I just can’t
get the words out”.
Which region of the brain is most likely affected in this patient’s seizures?
Cerebellum Frontal lobe Occipital lobe Parietal lobe Temporal lobe
Frontal lobe
Explanation:
Broca’s area is located in the frontal lobe of the brain. This is the area that allows the movements required to speak.
Wernicke’s area is in the parietal and temporal lobes and is involved in the understanding of written and spoken language.
The ischaemic cascade involves many processes which culminate in neuronal injury and cell death.
Reduction in the neuronal levels of which molecule starts this cascade.
Calcium
ATP
Sodium
Glutamate
Superoxide
ATP
Which artery is most frequently occluded in patients with stroke?
Anterior Cerebral Artery
Middle Cerebral Artery
Lenticulostriate Artery
Carotid artery
Posterior Cerebral Artery
Middle Cerebral Artery
Explanation:
Stroke is the area commonly affects speech and motor and sensory functions of the face, throat, hand and arm. This artery supplies part of the frontal lobe and the lateral surfaces of the temporal and parietal lobes.
