A newborn is protected against measles infection for several months after birth despite not being vaccinated. Which antibody class is responsible for this passive immunity?

A patient is found to have a mutation in the CD40 ligand (CD40L) gene. Which clinical finding is most consistent with the resulting defect in T-cell-dependent B cell activation?

A 55-year-old woman develops gradual swelling of her left arm 6 months after a mastectomy and axillary lymph node dissection for breast cancer. The swelling is painless but persistent. Examination shows non-pitting oedema and thickened skin. Which of the following is the most appropriate initial management for this patient?

A 70-year-old male presents with fatigue, weight loss, and bone pain. A complete blood count reveals anemia with a hemoglobin of 9.5 g/dL. A peripheral blood smear is ordered to investigate the morphology of the blood cells, revealing red blood cells stacked together in linear arrays resembling piles of coins. What is the correct term for this red blood cell finding?

A 55-year-old female is found to have an elevated serum protein level during a routine check-up. Subsequent testing reveals a serum monoclonal protein (M-protein) level of 35 g/L and a bone marrow biopsy shows 15% clonal plasma cells. She reports new onset of bone pain in her ribs, and X-rays confirm lytic lesions. Which specific feature distinguishes this patient’s diagnosis as Symptomatic Multiple Myeloma rather than Monoclonal Gammopathy of Undetermined Significance (MGUS)?

A 68-year-old man with a known diagnosis of multiple myeloma presents to the emergency department with confusion, constipation, and extreme thirst (polydipsia). His blood tests reveal an acute kidney injury and a significantly elevated serum calcium level. The medical team initiates aggressive intravenous hydration. Which pathological mechanism is the primary cause of this patient's renal impairment?

A medical student is revising the pathology of plasma cell disorders. They are reading about a condition where misfolded proteins deposit extracellularly in tissues, leading to organ damage such as restrictive cardiomyopathy and nephrotic syndrome. The text describes these protein deposits as insoluble and resistant to proteolysis. Which secondary protein structure characterizes the misfolded proteins described?

A 62-year-old man presents to the emergency department following a road traffic collision. He complains of severe mid-back pain and has difficulty standing upright. On examination, there is localised tenderness at the level of T10. Neurological examination of the lower limbs is normal. CT imaging demonstrates a wedge compression fracture involving a vertebra at this level.​

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Which of the following anatomical features would most reliably confirm that the injured vertebra is thoracic rather than cervical or lumbar?