We examined the hemodynamic changes induced by transient splenic arterial occlusion using a balloon catheter to investigate the hemodynamic effect of transcatheter splenic arterial embolization--a procedure that has been used since its introduction in 1973 as therapy for hypersplenism and more recently for portal hypertension. The blood flow volume was measured in 20 patients with liver disease using an ultrasonic duplex system (Toshiba SAL50A/SDL-01A). The portal venous pressure was also measured via a 3F catheter using a transducer. The catheter was placed in position by substituting it for a 25-gauge needle that had been inserted into the portal vein under ultrasonic guidance percutaneously and transhepatically. Splenic arterial occlusion caused a drop in splenic venous blood flow from 708 +/- 487 to 241 +/- 155 ml per min, in portal venous blood flow from 993 +/- 439 to 807 +/- 419 ml per min and in portal venous pressure from 17.4 +/- 7.2 to 14.4 +/- 6.1 mm Hg. The latter two reductions were less than expected from the decrease in the splenic venous blood flow volume. This phenomenon was caused by an increase in the mesenteric venous blood flow from 475 +/- 126 to 630 +/- 270 mm per min. This increase may be due to a compensatory mechanism under the control of a regulatory loop in the liver or portal vein, and there seems to be a relationship between splenic and intestinal circulation in portal hypertension that maintains hepatic circulation.

Embolization, Therapeutic↗

PubMedDate not supplied

A new method of determining the solute permeability of hollow-fiber dialysis membranes by means of laser lights traveling along optic fibers.

To develop a new method of determining solute permeability more simply and accurately, the authors employed light from a laser traveling along quartz optic fibers. Dialysis experiments at 310 K were made with a single hollow fiber containing aqueous test solutes. A membrane tube was sealed at either end with quartz optic fibers. Helium-neon and helium-cadmium laser lights emitted from one of these optic fibers into the test solution at wavelengths of 543 and 442 nm for vitamin B12 and cytochrome-C, respectively, were caught by the other optic fiber and detected with a silicon photodiode. The solute permeability for cytochrome-C obtained by this method was almost in agreement with that for beta-2-microglobulin by the radioisotope method. This study demonstrates the usefulness of light from a laser traveling along quartz optic fibers in determining the solute permeability of hollow-fiber dialysis membranes.

Cytochrome c Group↗

PubMedDate not supplied

Nipradilol, a new beta-blocker with vasodilatory properties, in experimental portal hypertension: a comparative haemodynamic study with propranolol.

The haemodynamic effects of nipradilol, a new non-selective beta-adrenoreceptor blocker with vasodilating actions like nitroglycerin, were examined in rats with portal hypertension due to portal vein stenosis. Portal hypertensive rats were divided into five groups receiving infusion of placebo, 3 mg of propranolol, 300, 600 and 1200 micrograms of nipradilol. At its highest dose, nipradilol achieved a reduction of 34.4 +/- 4.4% in heart rate which was similar to that in the propranolol group (36.5 +/- 2.4%). Also for other systemic haemodynamic parameters, the nipradilol 1200 micrograms group exhibited changes not significantly different from those in the propranolol group; mean arterial pressure (-13 vs -14%), cardiac index (-37 vs -31%) and systemic vascular resistance (+29 vs +32%). In contrast to the similar changes in the systemic circulation, a 1200 micrograms dose of nipradilol lowered portal pressure significantly more than propranolol (-4.3 +/- 0.6 vs -2.9 +/- 0.2 mmHg, P < 0.05). Nipradilol then reduced portal blood flow by 22% (P < 0.05) without a significant change in portocollateral resistance. On the other hand, propranolol not only caused a reduction in portal blood flow of 30% (P < 0.01), but also an increase in portocollateral resistance of 21% (P < 0.05). The results suggest that nipradilol may ensure a more effective control of portal hypertension than propranolol, presumably via its venodilatory action on portocollateral vessels.

Adrenergic beta-Antagonists↗