A number of disease processes are associated with an elevation in serum PSA. However, several studies have concluded that cycling is not an activity associated with an elevation in PSA. Herein, we summarise the literature and describe the case of a 54-year-old man who had presented to his General Practitioner (GP) with lower urinary tract symptoms 3 days after the completion of a 39-h endurance cycle ride. The PSA level was initially found to be elevated at 28 ng/ml, but decreased to 4 ng/ml and then 2 ng/ml within two and six months of the date of the cycle ride, respectively. It is probable that the elevation in PSA was caused by prolonged mechanical stimulation of the prostate during the cycle ride.

Plasma levels of the complement parent molecules C3, C4, and factor B and their split products, C3d, C4d, and Ba were measured in 12 patients undergoing cardiopulmonary bypass for coronary artery surgery. Alternative and common complement pathway activation, demonstrated by statistically significant rising levels of Ba (P less than 0.05), and C3d (P less than 0.05) and by elevated Ba:B (P less than 0.05) and C3d:C3 (P less than 0.05) ratios were found before the institution of cardiopulmonary bypass but following heparin administration suggesting that heparin may itself initiate alternative pathway activation. In addition, significant depletion of parent complement components and elevation of split product concentrations was seen during bypass suggesting classical and alternate pathway activation (P less than 0.01). This study clarifies the pathways of complement activation during bypass and presents evidence that heparin administration may initially activate the complement cascade.