Fixed-flexion, non-fluoroscopic radiography of the knee can provide reproducible JSW measurement using widely available X-ray equipment. This technique is more feasible for multicenter clinical studies and routine clinical use than are methods that rely on fluoroscopic alignment of the tibial plateau.

Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that is thought to function by interacting with two high-affinity receptors, flk-1 and flt-1. In an adult heart, angiogenesis can occur in a number of pathological conditions, including atherosclerosis, hypertrophy, and infarction. To determine the role played by VEGF, flk-1, and flt-1 in this process in vivo, we studied the expression of the growth factor and its receptors in a rat infarct model. After an acute myocardial infarction, we observed an initial rapid (1h) rise in VEGF (275%), flk-1 (375%), and flt-1 (400%) mRNA expression throughout the entire heart. Initial diffuse induction of VEGF, flk-1, and flt-1 expression in the left ventricle was later replaced by an increase predominantly limited to perimyocardial infarction area where angiogenesis was taking place. In situ hybridization showed at 6 h after infarction, viable myocytes adjacent to the infarct zone expressed markedly increased amounts of VEGF. At both 6 and 24 h, microvessels at the infarct edge overexpressed both flk-1 and flt-1 mRNAs; at 3 and 7 days new vessels infiltrating the infarct also overexpressed both receptors and continued for as late as 6 wk. In summary, acute myocardial infarction is accompanied by rapid and prolonged increase in expression of VEGF and its receptors with characteristic spatial and temporal kinetic. These findings suggest that the VEGF/VEGF receptor system plays an important role in the angiogenesis and stromal deposition associated with myocardial infarction.

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Vascular endothelial growth factor (VEGF) is a potent mitogen capable of stimulating angiogenesis. We examined the effect of VEGF administration in a model of chronic porcine myocardial ischemia. Nineteen pigs were instrumented with proximal left circumflex coronary artery (LCX) Ameroid constrictors. In eight animals VEGF (2 microgram) with heparin (50 U) was administered extraluminally to the LCX myocardium with an osmotic pump for 4 wk and 11 other animals served as controls. VEGF-treated animals demonstrated higher flow in the LCX territory during both rest and pacing compared with untreated controls (rest: 1.35 +/- 0.1 vs. 0.80 +/- 0.09 ml.min-1.g-1; pacing; 2.01 +/- 0.37 vs. 1.01 +/- 0.07 ml.min-1.g-1, P < 0.05, VEGF vs. controls). The observed improvement in regional coronary flow in VEGF-treated animals resulted in better preservation of endothelium-dependent microvessel relaxation as well as fractional LV shortening in the LCX territory during pacing in the VEGF-treated than in control animals (controls: 7.1 +/ 2.6 vs. 3.6 +/- 2.0%, rest vs. pacing; VEGF: 6.9 +/- 2.9 vs. 6.3 +/- 2.9%, rest vs. pacing). We conclude that VEGF administration in a gradual coronary occlusion model in pigs results in improvement of coronary flow and preservation of regional hemodynamics in the compromised myocardium.