Quantification of MGP at the 12-week time point. Three sections, each 28 μm apart, were measured using a microscope coupled to a computerized morphometry system (for details see “Materials and methods”). Quantification was expressed as the percentage staining of the total arterial medial area. Diets represent 12-week control, W&K (3 mg/g warfarin and 1.5 mg/g vitamin K₁), normal vitamin K diet (5 μg/g K₁), high vitamin K₁ (100 μg/g K₁), and high vitamin K₂ (100 μg/g K₂) after 6 weeks of W&K. ▪ represent total MGP, ⊡ represent cMGP, and □ represent ucMGP. Quantification was performed by 2 independent persons. Bars represent mean values ± SEM (n = 6).