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Question 1
Incorrect
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Which one of the following cells originates from a monocyte and resembles a macrophage?
Your Answer: Astrocyte
Correct Answer: Microglia
Explanation:Microglia act as the macrophages of the central nervous system, and they contribute to innate and adaptive immune responses. Studies have shown that microglial cells recognize monocyte antigens, and there are similarities between them that demonstrate that they originate from these monocytes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 2
Correct
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Angina pectoris develops when blood through the coronary artery becomes:
Your Answer: Restricted, limiting blood blow
Explanation:Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Incorrect
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Which of the following affects the magnitude of the action potential?
Your Answer: Extracellular Na+/K+ ratio
Correct Answer: Changes in the external Na+ concentration
Explanation:The magnitude of the action potential is determined by the sodium current. Increase in external sodium will result in increased influx of sodium and hence generation of a stronger action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 4
Incorrect
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In increasing order of concentration, the main anions in plasma are:
Your Answer: Proteins-, Phosphates-, HCO3-, Cl-
Correct Answer: Proteins-, HCO3-, Cl-,
Explanation:Anions are negatively charged ions and include: chloride Cl-, bicarbonate HCO3-, sulphate SO4-2, phosphate HPO4-2, and protein anions. Chloride it the most abundant anion followed by bicarbonate and then protein anions.
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This question is part of the following fields:
- Medicine
- Renal
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Question 5
Incorrect
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An elderly man presents with fever of 38°C and a very severe headache. His BP is 85/50 mm Hg. He has neck stiffness and photophobia. What is the most appropriate management?
Your Answer: CT head and Lumbar puncture
Correct Answer: CT head
Explanation:In elderly patients, symptoms suggestive of meningitis could be due to an intracranial mass lesion (such as abscess, tumour or an intracerebral haematoma). Therefore elderly patients are increased risk of cerebral herniation from an LP. A CT head should be done before an LP to exclude a mass lesion.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 6
Correct
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A 27-year-old female diagnosed with rheumatoid arthritis has failed to respond to methotrexate and sulfasalazine. Her GP decides to start her on etanercept injections. Which one among the following is an adverse effect associated with the use of etanercept?
Your Answer: Reactivation of tuberculosis
Explanation:Among the give options, reactivation of tuberculosis may occur in a patient under treatment with etanercept.Etanercept is a biological TNF inhibit commonly used to control ankylosing spondylitis, juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, and rheumatoid arthritis.Etanercept is a soluble receptor that binds both TNF-alpha and TNF-beta to inhibit the inflammatory response in joints and skin that is characteristic of these autoimmune disorders.The most common adverse effects include infections (viral, bacterial, and fungal – mostly upper respiratory tract infections) and injection site reaction (erythema, itching, pain, swelling, bleeding, bruising).Rarely it can also cause, reactivation of hepatitis B and TB, pneumocystis pneumonia, congestive cardiac failure, Steven-Johnson syndrome, toxic epidermal necrolysis, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 7
Correct
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The free radical most abundantly formed by the immune system is:
Your Answer: Hydroxyl radical
Explanation:Neutrophil and macrophage phagocytosis stimulates various cellular processes including the respiratory burst whereby increased cellular oxygen uptake results in the production of the potent oxidant bactericidal agents, hypochlorous acid and hydroxyl radical.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 8
Correct
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A 40-year-old patient under treatment for gout gave a history of progressive weakness of his limbs over 2 months. He noticed that it was particularly difficult for him to get up from the toilet seat and to get out of his car. He also felt some tingling and numbness of his toes at night, which was distressing. He was taking several medications which included Ibuprofen, perindopril, colchicine, vitamin supplements, and indapamide.On examination his pulse was 85/min, blood pressure was 140/90 mmHg and fundi revealed arteriovenous nipping. He had proximal lower limb weakness of 4/5 and absent ankle reflexes. Plantar reflexes were upgoing on both sides. His serum creatinine phosphokinase level was normal.What is the most likely diagnosis?
Your Answer: Colchicine toxicity
Explanation:The given clinical scenario is suggestive of myo-neuropathy and is most likely to be caused by colchicine toxicity. It gives rise to subacute proximal muscle weakness and on occasions can lead to an acute necrotizing myopathy. Creatine phosphokinase may be normal or may be elevated.Weakness resolves when the drug is discontinued but the neuropathic features remain.Death is usually a result of respiratory depression and cardiovascular collapse.Treatment is symptomatic and supportive, and the treatment for colchicine poisoning includes lavage and measures to prevent shock.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 9
Correct
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Which statement is incorrect regarding transcription of DNA?
Your Answer: A gene is always read in the 3’-5’ orientation and at 3’ promoter sites.
Explanation:In both prokaryotes and eukaryotes RNA polymerase acts in the 5′-3′ direction and hence the RNA is transcribed in this direction. The mRNA produced is immature as it has introns as well as exons presents. It undergoes a process known as splicing to remove the exons and then interacts with the ribosomes to form proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 10
Correct
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A 30-year-old female presented with upper abdominal pain. She was diagnosed with an unknown coagulopathy and has a previous history of stroke. She has been on warfarin therapy for the past 4 months. Her international normalised ratio (INR) was stabilised between 2.5 and 3.0. Noticing abnormal coagulation results, her surgeon has requested a medical consult.Her blood investigations revealed:White cell count: 13 × 109/lHaemoglobin (Hb): 11 g/dlActivated partial thromboplastin time (APTT): NormalPlatelets: 140 × 109/lINR: 6.0Pancreatic enzymes and liver function tests were normal.Other investigations:An ultrasound of the abdomen was normal.An upper GI endoscopy revealed mild gastritis. What is the most appropriate step to be taken regarding warfarin therapy?
Your Answer: Stop warfarin and observe
Explanation:The most appropriate treatment in this patient would be to stop warfarin therapy and keep the patient under observation.The drugs that lead to enhanced potency of warfarin include: disulfiram, trimethoprim-sulphamethoxazole, metronidazole, phenylbutazone, aspirin, heparin, and clofibrate. Liver disease, thrombocytopenia, hyperthyroidism also increase the oral anticoagulant potency.If the patient has minor bleeding and the international normalized ratio (INR) is >6.0, warfarin should be stopped; the INR should be rechecked daily and in addition to the stoppage of warfarin, vitamin K 2.5 mg oral or 0.5 mg intravenously should also be administered.In a patient with INR of 2.0 or 3.0, it takes two or three times longer for that individual’s blood to clot than someone who is not taking any anticoagulants. Most patients on warfarin have an INR goal of 2 to 3.If there is major bleeding then prothrombin complex concentrates 50 u/kg or fresh-frozen plasma 15 ml/kg may be considered.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 11
Incorrect
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A 76-year-old man has been admitted with a respiratory tract infection. On examination, he was found to be confused and dyspnoeic with O2 saturation of 88%. He has a 60 pack-year smoking history. An arterial blood gas analysis reveals CO2 retention. He has been deemed unfit for admission into the intensive care unit. The physician elects to begin a doxapram infusion. Among the following statements which best fits with the characteristics of doxapram?
Your Answer: Hypotension is a commonly seen side effect
Correct Answer: Epilepsy is a contraindication for doxapram use
Explanation:The statement that fits the characteristics of doxapram is, epilepsy is a contraindication for doxapram use. Concurrent use with theophylline may increase agitation not relaxation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 12
Correct
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Question 13
Correct
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A 41 year old woman who has a history of SLE presents with a dry cough, dyspnoea and fever. She is being treated with a monthly dose of IV cyclophosphamide for Grade IV nephropathy. The last cyclophosphamide dose was 10 years ago. Lab investigations are as follows: WCC: 2.3 (lymphocyte count 0.7)Platelets: 81Hb: 10.5ESR: 56CRP: 43PO2: 7.2 kPa, PCO2: 3.6 kPa after walking out to the toilet.Chest X ray was unremarkable apart from some patchy pulmonary infiltration.What is the likely diagnosis?
Your Answer: Pneumocystis carinii pneumonia (PCP)
Explanation:Pneumocystis carinii pneumonia, is an opportunistic fungal lung infection occurring almost exclusively in immunocompromised individuals. In 50% of cases, PCP is the first manifestation of AIDS (acquired immune deficiency syndrome), but it may be caused by other immunodeficiency disorders. PCP should be suspected in patients with a history of progressive dyspnoea and a dry cough with resistance to standard antibiotic treatment. Signs that support this diagnosis include a CD4 count < 200/μL, an increased beta-D-glucan level, and diffuse bilateral infiltrates on chest x-ray. Management of PCP includes high-dose trimethoprim/sulfamethoxazole (TMP/SMX), treatment of the underlying immunodeficiency disorder, and steroids in the case of severe respiratory insufficiency. TB is less likely to be present in this case as ESR is relatively low and chest x-ray appeared normal.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 14
Incorrect
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The ATPase of parietal cells moves:
Your Answer: None of the above
Correct Answer: H+ into the gastric lumen in exchange for a k+
Explanation:ATPase of the parietal cell is also known as the proton pump, which moves H+ ions into the gastric lumen in exchange for K+ ions into the cell.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 15
Correct
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The net effect of parathyroid hormone on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, decrease in phosphate
Explanation:Parathyroid hormone’s main target organs are the kidneys, bone, and intestine. In the kidney, it decreases reabsorption of phosphate and increases calcium reabsorption. It also promotes absorption of calcium from bone. PTH release results in a small drop in serum phosphate concentrations.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Correct
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Concerning the functional unit of the liver, which segment is most susceptible to hypoxic damage?
Your Answer: Zone 3
Explanation:From a metabolic perspective, the functional unit is the hepatic acinus (terminal acinus), each of which is centred on the line connecting two portal triads and extends outwards to the two adjacent central veins. The periportal zone I is nearest to the entering vascular supply and receives the most oxygenated blood, making it least sensitive to ischemic injury while making it very susceptible to viral hepatitis. Conversely, the centrilobular zone III has the poorest oxygenation, and will be most affected during a time of ischemia.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 17
Incorrect
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A 72 year old retired fisherman presents with weakness of shoulders and hips over the last four months. Finger flexion is also weak but the extension is normal. There has been some difficulty swallowing liquids. Past medical history is not significant except for sexually transmitted disease that he caught some 40 years ago in South Pacific and got treated with antibiotics. He smokes and drinks one or two tots of rum at the weekend. Creatine kinase level is 125. Which of the following investigations is most significant in establishing a diagnosis?
Your Answer: Anti Jo 1 antibody titres
Correct Answer: Muscle biopsy with electron microscopy
Explanation:Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 18
Incorrect
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Endotoxin will typically act on which one of the following cells, to produce endogenous pyrogens?
Your Answer: Neutrophils
Correct Answer: Monocytes
Explanation:Endotoxin, also known as lipopolysaccharides or lipoglycans, are molecules that consist of a lipid and a polysaccharide. They bind to many cell types, but especially to monocytes, promoting the secretion of proinflammatory cytokines, acting as a pyrogen.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 19
Correct
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A 78 year old woman presents to the clinic complaining of left sided temporal headaches and jaw claudication that has been going on for a month. A left temporal artery biopsy is negative. Results show:Hb: 130g/lPlatelets: 359*109/lWBC: 10*109/lCRP: 89mg/lWhich of the following options would be the next best step in the management of this patient?
Your Answer: Commence prednisolone
Explanation:Temporal arteritis is a chronic large- and medium-sized vessel vasculitis that typically involves the temporal arteries. Classical symptoms include temporal headaches, jaw claudication, amaurosis fugax. Physical exam shows scalp tenderness, palpation of the temporal area may demonstrate an absent pulse, knot-like swelling and vision loss. Lab results reveal an increased erythematous sedimentation rate and C-reactive protein. Temporal artery biopsy confirms the diagnosis. Management approach: high-dose systemic corticosteroids should be promptly administered even before the diagnosis is established. Temporal artery biopsy confirms the diagnosis. Inability to manage this or administer glucocorticoids might lead to development of blindness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 20
Correct
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Three adjacent nucleotides code for a particular amino acid. These are called codons. How many common amino acids are there and how many potential codon combinations make up the genetic code?
Your Answer: 20 amino acids, 64 codon combinations
Explanation:There are around 20 amino acids and 61 out of the 64 combinations of codon code for these 20 common amino acids.
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This question is part of the following fields:
- Genetics
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
