To date, vertebral venous valves have not been studied clinically or by sonography. This report reveals that these valves could be studied noninvasively by using sonographic techniques. Real-time sonography clearly showed the opening and closing of the two cusps of vertebral venous valves at the junction of the vertebral vein and the brachiocephalic vein, which move synchronously with the inter...

The study was performed on 82 small saphenous veins in human fetuses of both sexes aged 9 to 37 weeks. The earliest valves were observed in 13 week-old fetuses. In fetuses between 13 and 18 weeks old the number of valves increased from 1 to 8. In the older fetuses between 19 and 37 weeks the number of valves varied from 5 to 9 and does not seem to be related to age. During development more valv...

In 1992, based on extensive review of the literature, we concluded that in patients with mechanical prosthetic heart valves,1 (1) long-term (permanent) therapy with oral anticoagulants offers the most consistent protection, and (2) levels of oral anticoagulants that prolong the prothrombin time (PT) ratio to an international normalized ratio (INR) of 2.5 to 3.5 are satisfactory for tilting disk...

This paper presents a novel, highly sensitive and ultra-small fluorescent detection system, including an autonomous capillary fluid manipulation chip. The optical detector integrates a LED light source, all necessary optical components, and a photodiode with preamplifier into one package of about 2 cm × 2 cm × 2 cm. Also, the low-cost and simple pumpless microfluidic device works well in sample...

OBJECTIVES Proper valve selection is critical to ensure appropriate valve replacement for patients, because implantation of a small valve might place the patient at risk for persistent gradients. Labeled valve size is not the same as millimeter measure of prosthetic valve diameters or the annulus into which it will fit. Studies that use the labeled valve size in lieu of actual measured diameter...

OBJECTIVE To investigate the possible role of elastolytic cathepsins S, K, and V and their endogenous inhibitor cystatin C in adverse extracellular matrix remodeling of stenotic aortic valves. METHODS AND RESULTS Stenotic aortic valves were collected at valve replacement surgery and control valves at cardiac transplantations. The expression of cathepsins S, K, and V and cystatin C was studied...

PURPOSE Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical ...

In conventional internal combustion (IC) engines, engine valve displacements are fixed relative to crankshaft position. If these valves are actuated as a variable function of crankshaft angle, significant improvements in fuel economy can be achieved. Existing electromagnetically actuated variable-valve-timing (VVT) systems characteristically use springs to provide the large inertial power to mo...