Search

Your search keyword '"Carenza M"' showing total 105 results
Start Over Author "Carenza M"
105 results on '"Carenza M"'

25. Arginase Immobilization on Poly(hydroxyethyl acrylate) Matrix Beads.

Author

Veronese, F.M., Boccú, E., Caliceti, P., Lora, S., Carenza, M., and Palma, G.

Abstract

A study was made on the preparation and behaviour of polymer matrix im mobilized arginase, an enzyme involved in the urea cycle. Immobilization of purified calf liver arginase was obtained by a physical entrapment method based on the low temperature polymerization induced by radiation of a glass forming monomer mixed with an aqueous solution of the enzyme. Enzymatic activity was found to be retained in an acceptable range (30-35%) in a bead shaped matrix only when the monomer was hydroxyethylacrylate (HEA) purified by alkaline extraction and a particular sample preparation procedure was followed. The poly(hydroxyethyl acrylate) (PHEA) immobilized arginase was characterized by evaluating its chemical and enzymological properties such as Km, activation energy, stability to proteolytic enzymes, and activity de pendence on pH. Performance runs of continuous biocatalytic conversion of ar ginine to ornithine were carried out utilizing a reactor consisting of a column with immobilized arginase beads. After weeks of operation the substrate con version remained almost constant, indicating a practically unaltered enzy matic activity. PHEA immobilized arginase beads also retained their activity for days either in the presence of whole blood or when implanted intraperi toneally or subcutaneously into rats. No significant inflammation or other adverse reactions were observed after one week of residence of such implants. This seems promising for lowering the arginine blood level in specific diseases. [ABSTRACT FROM PUBLISHER]

Published
1989
Full Text
View/download PDF

50. Temperature-sensitive hydrogels: Potential therapeutic applications

Author

Paolo Caliceti, Gabriele Grassi, Mario Grassi, Gianfranco Guarnieri, Rossella Farra, Mario Carenza, Stefano Salmaso, Grassi, G., Farra, R., Caliceti, Paolo, Guarnieri, G., Salmaso, Stefano, Carenza, M., and Grassi, M.

Subjects
Pharmacology, chemistry.chemical_classification, Drug, media_common.quotation_subject, Nanotechnology, Polymer, Regenerative medicine, chemistry, Pharmacokinetics, Drug delivery, Self-healing hydrogels, medicine, Biophysics, Swelling, medicine.symptom, Drug Release Lower Critical Solution Temperature Bovine Spongiform Encephalopathy Poloxamer Polymer Volume Fraction, media_common, Macromolecule
Abstract

Thermo-sensitive polymers are appealing materials for several therapeutic applications, such as in regenerative medicine and in situ drug release. These macromolecules are characterized by the ability to undergo swelling/deswelling processes during temperature change-induced phase transitions. Swelling and shrinking temperatures depend on the specific physicochemical properties, namely salt concentration or pH, of the thermo-sensitive gels as well as the incubation environment. An understanding of the mechanisms underlying the gel-swelling equilibrium and kinetics is necessary for the selection of an appropriate gel in relation to the specific pharmaceutical application. Thermo-sensitive polymers used in medicine include polyacrylamides, polyvinyls, polyethers, polysaccharides, and polyphosphazenes. A few of them have been successfully used as 3-dimentional supports for cell cultivation, allowing for the production of scaffolds with excellent biologic properties for application in regenerative medicine. Stem cells that can undergo specific differentiation under the appropriate stimulation have also been cultivated. The ability of drug/polymer solutions to turn into gels at physiologic temperature has been exploited for local drug delivery. The prolonged in situ presence and slow drug release enhances the therapeutic performance of antibiotics used in urogenital pathologies, anti-inflammatory agents, and anticancer drugs. The reduced toxicity as well as lower fluctuations in peak-to-trough drug concentrations make these systems superior to traditional gels. Thermo-sensitive hydrogels have also been demonstrated to be interesting formulations for the delivery of biotechnological drugs. Proteins and oligonucleotides can be loaded under mild conditions, stabilized, and released at a controlled rate. Finally, thermo-reversible polymers have been investigated for protein conjugation to enhance the physicochemical, biologic, immunologic, and pharmacokinetic properties of biotechnological products.

Published
2005

Catalog

Books, media, physical & digital resources
See catalog results