A 45-year-old male with a history of osteoporosis is found to have low bone density on a DEXA scan. Laboratory tests show normal calcium and phosphate levels.  What is the most likely explanation for his low bone density? 

A 65-year-old male with a history of rheumatoid arthritis presents with fatigue and joint pain. Laboratory tests show a hemoglobin level of 11 g/dL, MCV of 85 fL, and elevated inflammatory markers.  What is the most likely cause of his anemia? 

A patient with a bacterial infection has elevated levels of mannose-binding lectin. Which pathway of the complement system is likely activated in this patient? 

What triggers the sickling of red blood cells in sickle cell disease? 

A 76-year-old man with Parkinson disease is evaluated for Pisa syndrome. He leans significantly to one side when walking. What additional symptom is likely to be contributing? 

What is the role of the protein p53 in the cell cycle? 

Which substances are released to aid leukocyte chemotaxis by producing vasodilation and increased capillary permeability? 

Which part of the shoulder joint is often affected by degenerative diseases? 

A 55-year-old female with a history of deep vein thrombosis is prescribed an anticoagulant that enhances the effects of prostacyclin.  What is the expected outcome of this therapy?

A 5-year-old boy presents with spontaneous joint bleeding and easy bruising. Laboratory tests show prolonged activated partial thromboplastin time (aPTT) and low factor VIII levels.  What is the most likely diagnosis?