We used a pulsed Doppler technique to examine the flow velocity pattern in the right ventricular outflow tract in 33 adults. In the patients with normal pulmonary artery pressure (mean pressure < 20 mm Hg, 16 patients), ejection flow reached a peak level at midsystole (137 + 24 msec, mean + SD), producing a domelike contour of the flow velocity pattern during systole. In contrast, the flow velocity pattern in patients with pulmonary hypertension (mean pressure ¢ 20 mm Hg,17 patients) was demonstrated to accelerate rapidly and to reach a peak level sooner (97 + 20 msec, p < .01); in 10 of the pulmonary hypertensive patients a secondary slower rise in flow velocity was observed during a deceleration, resulting in the midsystolic notching. The time to peak flow (acceleration time, AcT) and right ventricular ejection time (RVET) were measured from the flow velocity pattern. Either AcT or AcT/RVET decreased with increase in mean pulmonary artery pressure, and a very high correlation (r = -.90) was found between AcT/RVET and log,0 (mean pulmonary artery pressure). The use of this technique permitted the noninvasive estimation of the pulmonary artery pressure. Circulation 68, No. 2, 302-309, 1983. NONINVASIVE evaluation of pulmonary hypertension has been an important clinical problem for many years. The presence of pulmonary hypertension has been assessed by abnormalities in heart sounds,' in electrocardiographic tracings, or in chest x-rays,2 but to date, the accurate measurement of the pulmonary artery pressure requires the use of cardiac catheterization procedures. The development of echocardiographic techniques has allowed the investigation of pulmonic valve motion,3 which represents some characteristic abnormalities associated with pulmonary hypertension, such as rapid opening slope in systole,j5 attenuation or absence of the "a" dip,' prolongation of the ratio of right ventricular preejection period (RPEP) to right ventricular ejection time (RVET),57 and midsystolic semiclosure of pulmonic valve.)6 A recent experimental study8 emphasized that these abnormalities of the pulmonic valve motion were determined by abnormal flow changes in the pulmonary artery. However, flow characteristics with regard to pulmonary artery pressure either in the pulmonary artery or in the right ventricular outflow tract have not been successfully studied in man. Our objectives were to study the blood flow characteristics in the right ventricular outflow tract in patients with pulmonary hypertension by a pulsed Doppler technique9-I and to develop an index that would permit quantitative evaluation of pulmonary hypertension by noninvasive methods. Materials and methodsPatient selection. Thirty-eight patients admitted for diagnostic catheterization were examined by a pulsed Doppler technique. Five patients were excluded in whom Doppler recordings of flow velocity in the right ventricular outflow tract were not satisfactorily obtained because of poor penetration of ultrasound through the chest wall. Doppler examination was perfor...

In situ photopolymerization is an exciting new technique for tissue engineering. Two photocrosslinkable polysaccharides composed of alginate and hyaluronan are described that upon photolysis form soft, flexible, and viscoelastic hydrogels. The degree of methacrylate modification and thus covalent affects mechanical properties such as swelling, compression, and creep compliance. Significant swelling is observed in aqueous solution; these hydrogels can swell up to 14 times their dry weight. Both hydrogels exhibit low phase angles and (G*) values indicative of viscoelastic materials. The hyaluronan based hydrogel is stronger and more resilient than the corresponding alginate gel. SEM and AFM studies on both hydrogels show smooth and uniform surfaces at the macroscopic level with salient features observed only on the nanometer scale. Rapid polymerization by an optical trigger allows for controlled in situ photopolymerization in a minimally invasive manner, indicating that these hydrogels are relevant for biomedical applications such as sealing wounds and reconstructing soft tissues.

The present data revealed significant a contribution of the AT1-R/NF-kappaB pathway to diabetes-induced retinal inflammation, providing a mechanistic reason for targeting AT1-R or NF-kappaB in the treatment of diabetic retinopathy.

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Retinal protein expression and visual function are both disturbed by inflammation. Treatment with the AT1R blocker telmisartan efficiently prevented these signs of retinal neural damage through the reduction of local angiotensin II expression, the blockade of AT1R, and the relative upregulation of AT2R function.