2005a_Paper 1 – Medical Sciences

Which one of the following is the predominant stimulus to gastric acid secretion in a healthy individual?

With which of the following viruses is cancer of the cervix most strongly associated?

Diabetic neuropathic arthropathy is most likely to affect which of the following areas?

In a patient with IgA nephropathy who has a serum creatinine in the normal range, which of the following is the best predictor of developing end-stage renal failure?

Which of the following mechanisms best describes the mode of action of the sulphonylurea class of drugs?

Headache, blindness and jaw claudication secondary to end-organ ischaemia are common clinical manifestations of temporal arteritis (giant cell arteritis). Which of the following most accurately describes the common pathophysiologic mechanism of end-organ ischaemia in this condition?

Which of the following transfusion-related events is most frequently reported (episodes/unit transfused) with transfusion of unmodified red cells?

Which of the following anticonvulsant drugs is most likely to cause weight gain in young women?

The mechanism by which specific information encoded by viral DNA is transferred to messenger RNA (mRNA) is:

Which intervention has been best demonstrated to extend maximal life span in animals?

In patients with a certain genetic disorder, more than 95% of the abnormal genes have the same mutation. Analysis of a highly polymorphic locus in an intron of the gene shows similar allele frequencies in patients as in the general population.
Which one of the following genetic mechanisms is least likely to account for the predominance of one mutation in patients with this disorder?

A test has a sensitivity of 95% and a specificity of 90%. It is used to screen the general population for a rare condition that has a prevalence of 1 in 100,000.
What will the positive predictive value be nearest to?

In addition to decreased gastrointestinal calcium absorption, by which of the following mechanisms is prednis(ol)one most likely to cause net bone loss in a 65-year-old man?

A patient with aortic regurgitation has the following haemodynamic measurements:
cardiac output (CO) 7.5 L/minute
heart rate (HR) 75/minute
left ventricular end-diastolic volume (LVEDV) 200 mL
left ventricular end-systolic volume (LVESV) 50 mL
The regurgitant fraction is defined as the ratio of the regurgitant volume to the total volume flowing through the valve with each beat.
The regurgitant fraction in this patient is:

Which of the following best describes the antiviral effect of zanamivir on the influenza virus?

A 60-year-old man with a five-year history of type 2 (non-insulin-dependent) diabetes mellitus presents for a routine checkup. The most appropriate screening test for the presence of diabetic nephropathy is:

Which one of the following is the most important consideration in optimising treatment outcome from combination chemotherapy?

Which of the following is most characteristic of healthy ageing muscle?

Which one of the following best explains the mechanism of trigeminal neuralgia?

Which of the following is the strongest predictor of mortality in patients on haemodialysis for chronic renal failure?

Which one of the following cells of the immune system is most reliant on its release of mediators into the extracellular fluid surrounding the organism in order to carry out its role in eradication of foreign organisms?

Which of the following findings is most specific for a diagnosis of pernicious anaemia?

A 36-year-old woman has a very strong family history of premature coronary disease. Physical examination is normal. Fasting lipid profile reveals:
total cholesterol 9.5 mmol/L [2.5-5.2]
high-density lipoprotein (HDL) cholesterol 1.5 mmol/L [0.9-1.8]
triglycerides 2.00 mmol/L [0.10-1.85]
Which abnormality is most likely to be present?

The most common mechanism for malignant ascites is:

In a patient with unilateral facial weakness, which one of the following findings on physical examination most strongly suggests a peripheral cause for the facial weakness?

A 40-year-old woman with a 20-year history of systemic lupus erythamatosus (SLE) presents with severe anterior chest pain, dyspnoea and nausea.
Her SLE has manifested previously as arthritis, rash, mucosal ulceration and focal proliferative glomerulonephritis. She has had two miscarriages and delivered two normal children. Treatment has included hydroxychloroquine, prednis(ol)one in doses of 7.5 mg to 100 mg daily, intermittent cyclophosphamide and azathioprine. At presentation she is taking prednis(ol)one 7.5 mg daily and hydroxychloroquine.
Physical examination reveals obesity, pulse rate of 105/minute, blood pressure of 105/75 mmHg, normal heart sounds, and clear lung fields. The jugular venous pulse and pressure are obscured by fat.
Laboratory results show:
haemoglobin 124 g/L [115-165]
white cell count 3.4 x109/L [3.5-11.0]
lymphocytes 0.9 x109/L [1.5 – 4.0]
erythrocyte sedimentation rate (ESR) 35 mm/hr [0-20]
ECG shows ST-segment elevation in the anterior chest leads and sinus tachycardia. During the assessment, the patient develops ventricular fibrillation and dies. Which of the following is the most likely cause of her death?

Which of the following is most likely to cause predominantly zone 1 (periportal) rather than zone 3 (centrilobular) liver pathology?

During normal haemostasis, von Willebrand factor (vWF) plays a role in platelet adhesion/aggregation. During this process, which of the following is the primary binding site of vWF to platelets?

Which of the following is the most effective therapy for hyperphosphataemia associated with chronic renal failure?

Many familial disorders are due to mutations in genes for transcription factors. Which of the following statements is the best description of the role of a transcription factor? It:

Which of the following most accurately reflects the mechanism of complement consumption induced by complement component 3 (C3) nephritic factors?

Which of the following is the most important reason for not recommending gentamicin for the treatment of coliform central nervous system (CNS) infections?

The most common identifiable cause of epilepsy in the elderly is:

A 40-year-old woman treated for Hodgkin’s disease in her early twenties with mantle radiotherapy is at highest risk of which of the following cancers?

A 47-year-old male presents with haemoptysis on a background of a 47 pack year smoking history. A chest X-ray shows an irregular mass lesion in the right lower lobe, and sputum examination reveals large undifferentiated malignant cells.
Which of the following is the most sensitive method of determining if the mediastinal lymph nodes are involved with the disease?

The deterioration in glycaemic control over time seen in patients with type 2 (non-insulin-dependent) diabetes mellitus is primarily due to:

In a study of polymorphisms in the gene encoding the β2-adrenergic receptor, 20% of people were heterozygous for a polymorphism at codon 16 and 22% were heterozygous for a polymorphism at codon 27.
18% of the population were heterozygous at both loci.
Which one of the following statements is the best explanation for this observation?

A test is used to screen for a target disorder.
The best definition of the specificity of the test is “the proportion of individuals:

Of the following conditions, which has the greatest contraindication to therapy with bupropion (Zyban) for smoking cessation?

In therapy with immunosuppressive drugs (the relevant drugs are shown in brackets), knowledge of which of the following genotypes is most likely to be useful in preventing serious adverse drug events?

Carbimazole acts predominantly by inhibiting which of the following mechanisms?

Liberation of dietary cobalamin from R-proteins would be most likely to be adversely affected by:

The most common cause of chronic incontinence in the elderly is:

Intravenous infusion of which of the following blood components is most likely to be associated with a septic transfusion reaction?

In the treatment of hepatitis C infection with interferon and ribavirin, which one of the following is the best predictor of sustained virological response?

Efalizumab is a humanized monoclonal antibody active against an adhesion molecule (CD11a) and is used in the treatment of psoriasis. Which of the following is the best explanation for the therapeutic effect of efalizumab?

A 24-year-old is noted to have persistent microscopic haematuria following an insurance examination. Which one of the following factors provides the strongest indication for a renal biopsy?

Which one of the following statements is the best description of the molecular basis of a chimaeric protein (eg Bcr-Abl)?

A 57-year-old man with a long history of poorly controlled hypertension and smoking presents with sudden onset of right-sided weakness. On examination, his speech is slurred but content and comprehension are normal. There is a right facial weakness, with the right side of the soft palate elevating poorly. He has a right hemiparesis, power grade 2-3/5, in a pyramidal distribution with normal sensation to all modalities. Right-sided reflexes are enhanced with an extensor right plantar response.
The most likely cause of this stroke syndrome is left:

Which one of the following conditions is most likely to develop in a patient with panic disorder?

Which of the following dietary factors most increases the risk of gout?

The most common cause of diarrhoea in an adult traveller to a developing country is:

Bosentan is one of a number of new pharmacological therapies for pulmonary hypertension. Which of the following best describes the predominant mechanism of action of bosentan?