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Question 1
Incorrect
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Intracellular proteins tagged with mannose-6-phosphate are destined to which of the following organelles?
Your Answer: Nucleus
Correct Answer: Lysosome
Explanation:Lysosomal hydrolases are synthesized in the rough endoplasmic reticulum and specifically transported through the Golgi apparatus to the trans-Golgi network, from which transport vesicles bud to deliver them to the endosomal/lysosomal compartment. The explanation of how the lysosomal enzymes are accurately recognized and selected over many other proteins in the trans-Golgi network relies on them being tagged with a unique marker: the mannose-6-phosphate (M6P) group, which is added exclusively to the N-linked oligosaccharides of lysosomal soluble hydrolases, as they pass through the cis-Golgi network. Generation of the M6P recognition marker depends on a reaction involving two different enzymes: UDP-N-acetylglucosamine 1-phosphotransferase and α-N-acetylglucosamine-1-phosphodiester α-N-acetylglucosaminidase.
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This question is part of the following fields:
- Clinical Sciences
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Question 2
Incorrect
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Question 3
Incorrect
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A 54-year-old man is found collapsed in the street and is brought to the A&E. The results from the blood tests reveal Calcium = 1.62mmol/l and Albumin = 33g/l. The man is known to have a history of alcoholic liver disease. Which of the following is the best management regarding his calcium levels?
Your Answer: 10ml of 10% calcium chloride over 4 hours
Correct Answer: 10ml of 10% calcium gluconate over 10 minutes
Explanation:Acute, symptomatic hypocalcaemia is treated with 10ml of 10% calcium gluconate over 10 minutes.
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This question is part of the following fields:
- Clinical Sciences
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Question 4
Correct
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Primarily, funnel plots are used to do what?
Your Answer: Demonstrate the existence of publication bias in meta-analyses
Explanation:Funnel plots are graphical tools to assess and compare clinical performance of a group of care professionals or care institutions on a quality indicator against a benchmark. Incorrect construction of funnel plots may lead to erroneous assessment and incorrect decisions potentially with severe consequences.
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This question is part of the following fields:
- Clinical Sciences
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Question 5
Incorrect
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Which is the most common chromosomal defect in Down's syndrome?
Your Answer:
Correct Answer: Non-dysjunction
Explanation:Nondisjunction of chromosome 21 is the leading cause of Down syndrome. Two risk factors for maternal nondisjunction of chromosome 21 are increased maternal age and altered recombination.
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This question is part of the following fields:
- Clinical Sciences
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Question 6
Incorrect
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Which one of the following occurs during reverse transcriptase polymerase chain reaction?
Your Answer:
Correct Answer: RNA is converted to DNA
Explanation:Reverse transcription polymerase chain reaction is a laboratory technique combining reverse transcription of RNA into DNA and amplification of specific DNA targets using polymerase chain reaction. It is primarily used to measure the amount of a specific RNA. The main advantage of PCR is its sensitivity: only one strand of sample DNA is needed to detect a particular DNA sequence. It now has many uses including prenatal diagnosis, detection of mutated oncogenes and diagnosis of infections.
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This question is part of the following fields:
- Clinical Sciences
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Question 7
Incorrect
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Choose the correct statement regarding hyponatremia:
Your Answer:
Correct Answer: Hyperlipidaemia may cause pseudohyponatraemia
Explanation:The Hyperlipidaemia Effect: Pseudohyponatremia in Pancreatic Cancer; Patients who have disorders of cholestasis commonly present with volume depletion due to vomiting and poor oral intake, which, in turn, often leads to hypovolemic hyponatremia. It is less well known that disorders of cholestasis, including tumours of the hepatobiliary system, can be accompanied by hyperlipidaemia.
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This question is part of the following fields:
- Clinical Sciences
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Question 8
Incorrect
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A 32-year-old male has recently had a splenectomy following a motorcycle accident. He is up to date with all vaccinations which were offered as part of his childhood vaccination scheme. It is July. Which of the following vaccinations does he require in the first instance?
Your Answer:
Correct Answer: Pneumococcus, meningococcus type B and C, Haemophilus type B
Explanation:Acquired asplenia or hyposlenia can occur following splenectomy. Hyposplenism is used to describe reduced (‘hypo-‘) splenic functioning and is associated with increased risk of sepsis from polysaccharide encapsulated bacteria. In particular, patients are at risk from Streptococcus pneumoniae, Haemophilus influenzae, and meningococcus. The risk is elevated as much as 350–fold.
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This question is part of the following fields:
- Clinical Sciences
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Question 9
Incorrect
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Which one of the following statements regarding interleukin 1 (IL-1) is true?
Your Answer:
Correct Answer: It is released mainly by macrophages/monocytes
Explanation:Interleukin 1 alpha and interleukin 1 beta (IL1 alpha and IL1 beta) are cytokines that participate in the regulation of immune responses, inflammatory reactions, and hematopoiesis. It is secreted mainly by macrophages and monocytes and acts as a costimulator of T cell and B cell proliferation.
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This question is part of the following fields:
- Clinical Sciences
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Question 10
Incorrect
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A 29-year-old male patient with a history of three previous chest infections in the past seven months presents with fever, pleuritic pain and productive cough. Chest x-ray shows lobar consolidation and the diagnosis of a fourth chest infection is established, after sputum culture reveals Haemophilus influenzae. The previous chest infections were due to Streptococcus pneumoniae. After a period of six weeks, a full blood count, urea, CRP, electrolytes and chest x-ray turn out as normal. What is the investigation you would choose next?
Your Answer:
Correct Answer: Serum immunoglobulins
Explanation:Hypogammaglobulinemia occurs due to a variety of underlying primary or secondary immunodeficient states, including HIV which is suspected in this case. The most commonly recognised clinical feature is recurrent infection.
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This question is part of the following fields:
- Clinical Sciences
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Question 11
Incorrect
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Choose the cell organelle involved in the synthesis of lipids:
Your Answer:
Correct Answer: Smooth endoplasmic reticulum
Explanation:The Smooth endoplasmic reticulum (ER) is the major site at which membrane lipids are synthesized in eukaryotic cells. Because they are extremely hydrophobic, lipids are synthesized in association with already existing cellular membranes rather than in the aqueous environment of the cytosol. Although some lipids are synthesized in association with other membranes, most are synthesized in the ER. They are then transported from the ER to their ultimate destinations either in vesicles or by carrier proteins.
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This question is part of the following fields:
- Clinical Sciences
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Question 12
Incorrect
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A 23-year-old woman presents to the A&E with a 24-hour-history of gradual-onset fever, light sensitivity and headache. Clinical examination reveals neck stiffness and an area of rash which does not disappear upon pressure on her right shin. Anamnesis reveals a history of 3 episodes of meningococcal meningitis in the past and she was started on ceftriaxone for another suspected meningitis. However, you suspect that the patients might be immunodeficient. Which immunodeficiency does she most probably have?
Your Answer:
Correct Answer: C5-9 deficiency
Explanation:Pneumococcal meningitis is the most common and severe form of bacterial meningitis. Fatality rates are substantial, and long-term sequelae develop in about half of survivors. Disease outcome has been related to the severity of the proinflammatory response in the subarachnoid space. The complement system, which mediates key inflammatory processes, has been implicated as a modulator of pneumococcal meningitis disease severity in animal studies. C5 fragment levels in cerebrospinal fluid (CSF) of patients with bacterial meningitis correlated with several clinical indicators of poor prognosis. The common terminal pathway consists of complement components C5–C9, and activation forms the anaphylatoxin C5a, a strong proinflammatory mediator, and the membrane attack complex (MAC), which creates pores in the bacterial cell wall (12). Deficiencies in these late complement components have been recognized as a cause of recurrent and familial meningococcal infections.
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This question is part of the following fields:
- Clinical Sciences
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Question 13
Incorrect
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A study is developed to assess a new anti-hypertensive drug and two groups of patients are randomly chosen. The first group takes an established anti-hypertensive drug for 3 months and the second group receives the new drug, again for 3 months. To assess the efficacy of the new drug, blood pressure is measured before and after taking the drug in both groups of patients. After a period of 1 month off medication, the groups swap medication and blood pressure is measured again, finally the difference in blood pressure after receiving each drug is calculated. Which of the following significance tests would you apply to assess the results of the study?
Your Answer:
Correct Answer: Student's paired t-test
Explanation:A t test is a type of statistical test that is used to compare the means of two groups. It is one of the most widely used statistical hypothesis tests in pain studies. There are two types of statistical inferences: parametric and nonparametric methods. Parametric methods refer to a statistical technique in which one defines the probability distribution of probability variables and makes inferences about the parameters of the distribution. In cases in which the probability distribution cannot be defined, nonparametric methods are employed. T tests are a type of parametric method; they can be used when the samples satisfy the conditions of normality, equal variance, and independence. In this case the data is parametric, and they belong to the same patients, so a paired t test should be used.
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This question is part of the following fields:
- Clinical Sciences
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Question 14
Incorrect
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A woman with severe renal failure undergoes a kidney transplant. However, after a few hours, she develops fever and anuria. The doctors are suspecting hyperacute organ rejection. Which are the cells primarily responsible for hyperacute organ rejection?
Your Answer:
Correct Answer: B Cells
Explanation:Hyperacute rejection appears in the first minutes following transplantation and occurs only in vascularized grafts. This very fast rejection is characterized by vessel thrombosis leading to graft necrosis. Hyperacute rejection is caused by the presence of antidonor antibodies existing in the recipient before transplantation. These antibodies induce both complement activation and stimulation of endothelial cells to secrete Von Willebrand procoagulant factor, resulting in platelet adhesion and aggregation. The result of these series of reactions is the generation of intravascular thrombosis leading to lesion formation and ultimately to graft loss. Today, this type of rejection is avoided in most cases by checking for ABO compatibility and by excluding the presence of antidonor human leukocyte antigen (HLA) antibodies by cross-match techniques between donor graft cells and recipient sera. This type of rejection is also observed in models of xenotransplantation of vascularized organs between phylogenetically distant species when no immunosuppressive treatment is given to the recipients.
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This question is part of the following fields:
- Clinical Sciences
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Question 15
Incorrect
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A 33-year-old woman has missed her last two periods and has been lactating. Upon anamnesis, she claims she's lost weight and she's been suffering from vaginal dryness. The endocrinologist suggests that she checks her prolactin levels. Which of the following inhibits prolactin release from the hypophysis?
Your Answer:
Correct Answer: Dopamine
Explanation:Dopamine (DA) holds a predominant role in the regulation of prolactin (PRL) secretion. Through a direct effect on anterior pituitary lactotrophs, DA inhibits the basally high-secretory tone of the cell. It accomplishes this by binding to D2 receptors expressed on the cell membrane of the lactotroph, activation of which results in a reduction of PRL exocytosis and gene expression by a variety of intracellular signalling mechanisms.
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This question is part of the following fields:
- Clinical Sciences
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Question 16
Incorrect
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The average weight of 64 patients with type 2 diabetes mellitus was 81 kg, with a standard deviation of 12 kg. What is the standard error of the mean?
Your Answer:
Correct Answer: 1.5
Explanation:The SEM is dependent on the variation in the population and the number of the extracted samples. A large variation in the population causes a large difference in the sample means, ultimately resulting in a larger SEM. However, as more samples are extracted from the population, the sample means move closer to the population mean, which results in a smaller SEM. In short, the SEM is an indicator of how close the sample mean is to the population mean. Standard error of the mean = standard deviation / square root (number of patients)
The standard error of the mean is calculated by the standard deviation / square root (number of patients)= 12 / square root (64) = 12 / 8 = 1.5
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This question is part of the following fields:
- Clinical Sciences
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Question 17
Incorrect
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Which one of the following statements regarding epidemiological measures is correct?
Your Answer:
Correct Answer: Cross-sectional surveys can be used to estimate the prevalence of a condition in the population
Explanation:The incidence rate is the number of new cases per population at risk in a given time period. For example, if a population initially contains 1,000 non-diseased persons and 28 develop a condition over two years of observation, the incidence proportion is 28 cases per 1,000 persons per two years, i.e. 2.8% per two years.
Prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seat-belt use). It is derived by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage, or as the number of cases per 10,000 or 100,000 people.
Incidence should not be confused with prevalence, which is the proportion of cases in the population at a given time rather than rate of occurrence of new cases. Thus, incidence conveys information about the risk of contracting the disease, whereas prevalence indicates how widespread the disease is. -
This question is part of the following fields:
- Clinical Sciences
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Question 18
Incorrect
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A 19-year-old woman is admitted with diabetic ketoacidosis (DKA). It is her fourth episode in the past two months and she's known to be a type 1 diabetes mellitus patient. The doctors suspects she's non-compliant with her treatment to keep her weight down. She often self-discharges after 24 hours. What is the single most appropriate management?
Your Answer:
Correct Answer: Have a chat after the ward round about why she thinks her control is so bad
Explanation:In many Western countries and health plans in the United States, patients have a primary care physician who acts as a formal gatekeeper for medical specialist care and thereby determines together with the patient whether or not a patient requires medical specialist care. Ideally in such systems, patients are treated in primary care if possible, and referred to medical specialist care if necessary. For the gatekeeper system to be effective, it is vital that adequate decisions are made about when and who to refer. But it is also important that referred patients comply with the referral by consulting a medical specialist. In this case, the GP should discuss with the patient the reasons why she cannot follow the treatment plan. In other words, the GP should detect why the patient is being non-compliant.
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This question is part of the following fields:
- Clinical Sciences
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Question 19
Incorrect
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What is the correct formula to calculate the positive predictive value? (TP = true positive; FP = false positive; TN = true negative; FN = false negative)
Your Answer:
Correct Answer: TP / (TP + FP)
Explanation:Positive predictive value is the probability that subjects with a positive screening test truly have the disease.
Positive predictive value = true positive / ( true positive + false positive)
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This question is part of the following fields:
- Clinical Sciences
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Question 20
Incorrect
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Which one of the following immunological changes is seen in progressive HIV infection?
Your Answer:
Correct Answer: Increase in B2-microglobulin levels
Explanation:The immunological changes in HIV include depletion in CD4+ T cell, cytokine dysregulation and immune dysfunction. The dominant immunologic feature of HIV infection is progressive depletion of the helper T cell (CD4+ T cell), which reverses the normal CD4:CD8 ratio and subsequently lead to immunodeficiency. Other imuunological changes include:
increased B2-microglobulin
decreased IL-2 production
polyclonal B-cell activation
decreased NK cell function
reduced delayed hypersensitivity responses -
This question is part of the following fields:
- Clinical Sciences
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Question 21
Incorrect
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What kind of receptor is the nitric oxide receptor?
Your Answer:
Correct Answer: Guanylate cyclase receptor
Explanation:Soluble guanylyl cyclase (GC-1) is the primary receptor of nitric oxide (NO) in smooth muscle cells and maintains vascular function by inducing vasorelaxation in nearby blood vessels. GC-1 converts guanosine 5′-triphosphate (GTP) into cyclic guanosine 3′,5′-monophosphate (cGMP), which acts as a second messenger to improve blood flow.
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This question is part of the following fields:
- Clinical Sciences
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Question 22
Incorrect
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A new blood test developed to screen individuals for cardiac failure was performed on 500 patients. The results were positive for 40 out of 50 patients with echocardiography-established heart failure. However, the test was also positive for 20 patients with no signs of heart failure. What is the positive predictive value of the test?
Your Answer:
Correct Answer: 0.66
Explanation:Positive predictive value = TP (true positives) / [TP + FP (false positives)] = 40 / (40 + 20) = 0.66
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This question is part of the following fields:
- Clinical Sciences
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Question 23
Incorrect
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A 42-year-old patient has been admitted with a very swollen and painful right knee. He was unable to walk on it so came into hospital. It is currently being treated as gout with non steroidal anti-inflammatory drugs. You notice he is of short stature, has shortened arms and legs and a flat nasal bridge. A mutation in which gene is responsible for this condition?
Your Answer:
Correct Answer: Fibroblast growth factor receptor
Explanation:Achondroplasia is a common cause of dwarfism. It is caused by a mutation in fibroblast growth factor receptor 3 (FGFR3). In normal development FGFR3 has a negative regulatory effect on bone growth. In achondroplasia, the mutated form of the receptor is constitutively active and this leads to severely shortened bones. The effect is genetically dominant, with one mutant copy of the FGFR3 gene being sufficient to cause achondroplasia, while two copies of the mutant gene are invariably fatal. A person with achondroplasia thus has a 50% chance of passing dwarfism to each of their offspring. People with achondroplasia can be born to parents that do not have the condition due to spontaneous mutation. It occurs as a sporadic mutation in approximately 80% of cases (associated with advanced paternal age) or it may be inherited as an autosomal dominant genetic disorder.
People with achondroplasia have short stature, with an average adult height of 131 centimeters (52 inches) for males and 123 centimeters (48 inches) for females. -
This question is part of the following fields:
- Clinical Sciences
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Question 24
Incorrect
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A study's objective is to find the normal reference range for IgE levels in the adult population. What percentage of individuals will have IgE levels higher than 2 standard deviations from the mean, assuming that the IgE levels follow a normal distribution?
Your Answer:
Correct Answer: 2.30%
Explanation:Normal distribution describes the spread of many biological and clinical measurements. Usually, 68.3% lies within 1 standard deviation (SD) of the mean, 95.4% lies within 2 SD of the mean and 99.7% lies within 3 SD of the mean.
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This question is part of the following fields:
- Clinical Sciences
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Question 25
Incorrect
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A 19-year-old female is admitted with a headache, photophobia, fever and confusion. She is managed with antibiotics. What is the mechanism of action of the most commonly used first line antibiotic class?
Your Answer:
Correct Answer: Inhibition of cell wall synthesis
Explanation:In adults, the most common symptom of meningitis is a severe headache, occurring in almost 90% of cases of bacterial meningitis, followed by nuchal rigidity (the inability to flex the neck forward passively due to increased neck muscle tone and stiffness). Other signs commonly associated with meningitis include photophobia (intolerance to bright light) and phonophobia (intolerance to loud noises).
In the United Kingdom empirical treatment consists of a third-generation cefalosporin such as cefotaxime or ceftriaxone. In the USA, where resistance to cefalosporins is increasingly found in streptococci, addition of vancomycin to the initial treatment is recommended. Penicillins, cephalosporins, carbapenems and monobactams all act via inhibition of cell wall synthesis. -
This question is part of the following fields:
- Clinical Sciences
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Question 26
Incorrect
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A study was developed to assess a new oral antithrombotic drug on the chance of stroke in high-risk patients, compared to warfarin. The total number of patients receiving the new drug were 200 compared to 600 who were receiving warfarin. From the ones receiving the new drug, 10 patients had a stroke within 3 years, compared to 12 patients who were receiving warfarin and had a stroke. What is the relative risk of having a stroke within 3 years for patients receiving the new drug?
Your Answer:
Correct Answer: 2.5
Explanation:Relative Risk = (Probability of event in exposed group) / (Probability of event in not exposed group)
Experimental event rate, EER = 10 / 200 = 0.05Control event rate, CER = 12 / 600 = 0.02
Therefore the relative risk = EER / CER = 0.05 / 0.02 = 2.5
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This question is part of the following fields:
- Clinical Sciences
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Question 27
Incorrect
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A 40-year-old female patient with a history of rheumatoid arthritis is diagnosed with type 1 renal tubular acidosis. What is the most probable sequela of this condition?
Your Answer:
Correct Answer: Nephrocalcinosis
Explanation:Distal renal tubular acidosis is due to defective proton secretion from the alpha intercalated cells of the distal tubule caused by dysfunction of the H+/K+ antiporter on the apical membrane. This leads to failure of H+ excretion thereby causing systemic acidosis and potassium depletion. Inability to lower the urine pH below 5.3 in the presence of systemic acidosis is the diagnostic hallmark of type I or distal renal tubular acidosis. Hypercalciuria, hypocitraturia and elevated urinary pH observed in distal renal tubular acidosis can lead to nephrocalcinosis and may cause renal calculi, obstructive uropathy and renal failure necessitating surgical or endoscopic stone extraction.
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This question is part of the following fields:
- Clinical Sciences
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Question 28
Incorrect
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A 75-year-old woman experiences weakness of her left hand. Clinical examination reveals wasting of the hypothenar eminence and weakness of finger abduction and thumb adduction. The lesion is most probably located at:
Your Answer:
Correct Answer: Ulnar nerve
Explanation:Patients with compressive neuropathy of the ulnar nerve typically describe numbness and tingling of the ulnar-sided digits of the hand, classically in the small finger and ulnar aspect of the ring finger. Among the general population, symptoms usually begin intermittently and are often worse at night, particularly if the elbow is flexed while sleeping. As the disease progresses, paraesthesia may occur more frequently and during the daytime.
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This question is part of the following fields:
- Clinical Sciences
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Question 29
Incorrect
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A 36-year-old lady with back pain is found to have loss of sensation of the kneecaps. Choose the dermatome most likely compromised:
Your Answer:
Correct Answer: L4
Explanation:L4 dermatome distribution includes the kneecaps.
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This question is part of the following fields:
- Clinical Sciences
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Question 30
Incorrect
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Which one of the following statements best describes a type II statistical error?
Your Answer:
Correct Answer: The null hypothesis is accepted when it is false
Explanation:In statistical hypothesis testing there are 2 types of errors:
– type I: the null hypothesis is rejected when it is true – i.e. Showing a difference between two groups when it doesn’t exist, a false positive.
– type II: the null hypothesis is accepted when it is false – i.e. Failing to spot a difference when one really exists, a false negative. -
This question is part of the following fields:
- Clinical Sciences
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SESSION STATS - PERFORMANCE PER SPECIALTY
