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At least 883 records · Page 49Linked to original sources
PubMed1981

Angiodysplasia of the right colon treated by embolization with ivalon (polyvinyl alcohol).

Angiodysplasia of the colon is being recognized with increasing frequency as a source of lower gastrointestinal bleeding in the elderly. In one patient with colonic angiodysplasia, superselective segmental embolization of the ileo-colic artery with Ivalon resulted in the cessation of bleeding without causing bowel infarction. However, because of the development of collateral branches to the angiodysplastic malformation, bleeding recurred. While colectomy remains the treatment of choice in younger patients, in high risk patients embolization with a permanent embolic material, such as Ivalon, is an attractive alternative.

Aged↗
PubMed2005

Preparation of bioactive glass-polyvinyl alcohol hybrid foams by the sol-gel method.

A new class of materials based on inorganic and organic species combined at a nanoscale level has received large attention recently. In this work the idea of producing hybrid materials with controllable properties is applied to obtain foams to be used as scaffolds for tissue engineering. Hybrids were synthesized by reacting poly(vinyl alcohol) in acidic solution with tetraethylorthosilicate. The inorganic phase was also modified by incorporating a calcium compound. Hydrated calcium chloride was used as precursor. A surfactant was added and a foam was produced by vigorous agitation, which was cast just before the gel point. Hydrofluoric acid solution was added in order to catalyze the gelation. The foamed hybrids were aged at 40 degrees C and vacuum dried at 40 degrees C. The hybrid foams were analyzed by Scanning Electron Microscopy, Mercury Porosimetry, Nitrogen Adsorption, X-ray Diffraction and Infra-red Spectroscopy. The mechanical behavior was evaluated by compression tests. The foams obtained had a high porosity varying from 60 to 90% and the macropore diameter ranged from 30 to 500 microm. The modal macropore diameter varied with the inorganic phase composition and with the polymer content in the hybrid. The surface area and mesopore volume decreased as polymer concentration increased in the hybrids. The strain at fracture of the hybrid foams was substantially greater than pure gel-glass foams.

Biocompatible Materials↗
PubMed1984

Effect of polyvinyl phosphonates and ethane hydroxy diphosphonate on mineralization of ectopic bone.

The effects of polymeric polyphosphonate and of ethane hydroxydiphosphonate on the development of ectopic bone were compared at different stages of bone development. The diphosphonate affected bone development at different stages, as reflected by alkaline phosphatase and aryl sulphatase activities, as well as by the creation of calcium ions by bone and on its readiness to undergo isotopic exchange. The polymeric polyphosphonate (mol. wt., 3500-8000), on the other hand, did not exhibit any of these effects, although it did inhibit the activity of the enzymes in vitro to an extent comparable with that of the diphosphonate. The results corroborate the assumption that the effects of polymeric polyphosphonates on hard tissues are confined to the extracellular space while the effects of diphosphonates on bone development are due to intracellular activity and not to sequestering of extracellular calcium.

Alkaline Phosphatase↗
PubMed1992

Parameters affecting the adsorption of ligands to polyvinyl chloride plates in enzyme immunoassays.

In the present work, we studied the efficacy of three blocking agents (HSA, BSA and OVA) in the inhibition of non-specific binding to PVC plates. According to the inhibition data, 1% OVA was the most effective blocking agent. On the other hand, the presence of detergents in all of the blocking solutions drastically decreased the percent inhibition of the non-specific binding. Furthermore, the effect of ligand concentration on adsorption and the kinetics of ligand adsorption to PVC plates were also investigated. Ligand adsorption is a linear function of input up to a limit (around 8.70 ng/mm2) where saturation is reached. The rate of adsorption of pure human IgG to PVC plates was proportionally increased with the temperature, as shown by proportional rate constants almost 2 times faster at 37 degrees C than at 4 degrees C. These results have practical implications for investigators using PVC for immunoassays and should be taken into consideration when designing such assays.

Animals↗