Search

Hepatocyte based artificial liver support systems are under investigation to support acute liver failure patients. The main purpose of such systems is to serve as a bridge to liver transplantation, or to promote spontaneous liver recovery. Limitation in mass-transfer capacity makes hollow-fiber bioreactors unsuited for long-term functioning of hybrid devices. We developed a novel radial-flow bioreactor in which the fluid perfuses the module from the center to the periphery, after having diffused through a space occupied by a three-dimensional structure filled with the hepatocytes. Five grams of freshly isolated porcine hepatocytes were seeded into uncoated, woven-non woven, hydrophilic polyester fabric, overlaid by two polyethersulfone membranes. Liver cells were perfused with 37 degrees C-warm, oxygenated, serum-free tissue culture medium, in which NH4Cl and Lidocaine were added at the final concentration of 1 mM and 60 micrograms/ml, respectively. Ammonium chloride removal, urea synthesis, monoethylglycinexylide (MEGX), pO2, pCO2, and pH were measured throughout the 14 day duration of the study. In a separate set of experiments, a scaled-up version of the radial flow bioreactor containing 150 grams of cells was perfused for 7 h with recirculating human plasma and MEGX production was monitored. During the 2 weeks of the study, an increasing production of urea was paralleled by constant ammonium removal. MEGX concentration after Lidocaine addition increased throughout the 14 days of perfusion with tissue culture medium, as well as after 7 hour perfusion with human plasma. Under transmission and scanning electron microscopy cells appeared attached to the polyester and one to each other, displaying ultrastructural features typical of functioning hepatocytes. Our study showed that liver cells were metabolically active when perfused into the radial-flow bioreactor. This configuration allowed close contact between media, or plasma, and cells at a physiological flow rate, by equalizing the concentration of the perfusing components, including O2, throughout the module. Our results suggest a potential use of this system for temporary extracorporeal liver support in acute hepatic failure patients.

Background This study aims to investigate the incidence and the relative risk factors of retinopathy of prematurity (ROP) and posterior-ROP (P-ROP): ROP in Zone I and posterior Zone II, as well as to analyze the occurrence of surgical treatment of ROP and to evaluate the short term outcome of the disease in Italy. Methods It is a prospective multicenter observational study; all infants with a birth weight (BW) ≤ 750 g and/or a gestational age (GA) ≤27 weeks born between January 1st 2008 and December 31st 2009 in 25 III level Italian neonatal intensive care units were eligible for the study. Results 421 infants were examined: 265 (62.9%) developed ROP and 102 (24.2%) P-ROP. Following the multivariate analysis erythropoietin-therapy (p

The sclerosant effect of injected tetradecyl sulfate of sodium (STS) and hydroxy polyethoxy dodecan (HPD) was studied in the rat femoral vein. Intravenous (i.v.) and intravenous plus perivenous (i.v. + p.v.) injections of both sclerosants and physiologic saline were compared as to vein lumen occlusion, fibrosis, phlogosis, and damage to the artery and surrounding nervous and muscular tissues. The study was carried out in 30 rats treated by STS, in 30 treated by HPD, and 15 animals were injected with saline. The neurovascular bundle and adjacent muscle were removed at 48 h, 7 and 30 days and examined histologically. I.v. injections of STS produced a solid occlusion of the vein in a significant number of cases, after 30 days (P less than 0.01). A statistically significant number of solid occlusions of the femoral vein resulted after i.v. + p.v. injection of STS and HPD, at 48 h, 7 and 30 days (P less than 0.05; P less than 0.01). There was no significant difference between STS and HPD after i.v. + p.v. injection. After i.v. + p.v. we recorded a marked inflammation of muscle with signs of focal necrosis, at 48 h and 7 days. Our study indicated that i.v. + p.v. injection of STS and HPD provided a high degree of efficacy as regards vein occlusion. On the other hand, i.v. + p.v. injection induced a severe inflammation and necrosis of the tissues surrounding the sclerosed vein. Extrapolating our results to the endoscopic sclerotherapy for esophageal variceal bleeding, we conclude that paravariceal injection of sclerosants is a dangerous procedure, even though efficacious to reduce variceal hemorrhage, owing to the high risk of iatrogenic ulcers and esophageal perforation caused by muscular and mucosal necrosis.