MG Pischiutta

Bio: MG Pischiutta is an academic researcher from Catholic University of the Sacred Heart. The author has contributed to research in topics: Alkaline phosphatase & Guanidinium chloride. The author has an hindex of 2, co-authored 4 publications receiving 61 citations.

Ascorbic acid stability in aqueous solutions.

Abstract: Different water purity provokes a great variation of the stability of ascorbic acid and isoascorbic acid solutions. The effect of temperature on ascorbate aerobic oxidation was assessed by means of Arrhenius plots from which thermodynamic parameters were derived. The presence of bovine serum albumin drastically reduces the vitamin oxidation rate regardless of stereoisomerism. On the other hand the interaction with alkaline phosphatase, an enzyme inhibited by preincubation with vitamin C, does not modify significantly the stability in the experimental conditions used.

Early conformational changes and activity modulation induced by guanidinium chloride on intestinal alkaline phosphatase.

Abstract: Moderate concentrations of guanidinium chloride induce both instantaneous and time-dependent modifications of the catalytic and optical properties of intestinal alkaline phosphatase, which undergoes consecutive conformational transitions at about 0.05 M, 0.25 M and 1.0 M denaturant. A paradoxical activation is observed up to 1.0 M-guanidine, with a maximum at 0.25 M- and a mid-point around 0.5 M-guanidine. Difference absorbance and fluorescence spectra imply a change in the state of ionization of the protein residues, with variation in molecular size suggested by light-scattering. Random-coil formation is indicated by a lower fluorescence yield, a more polar environment of the aromatic residues and another separate tryptophan emission. Iodide quenching confirms the alterations of conformation. Deprotonation favours the loss of the intramolecular constraints and the enhancement of the structure disruption by guanidine.

Comparison of kinetic and optical changes during guanidine denaturation of intestinal alkaline phosphatase.

Abstract: The modifications of the activity of calf intestinal Alkaline Phosphatase treated with moderate amounts of guanidinium chloride are compared with the conformational changes observed by ultraviolet absorbance and intrinsic fluorescence. The time course of catalytic and optical properties of the treated enzyme develops through two distinct steps: an instantaneous and a time-dependent one. The immediate effect of guanidine is to lower emission yield, to shift the emission maximum of the enzyme to longer wavelengths and to enhance the absorbance of the protein. The rapid conformational transition determines a paradoxical activation at low effector concentration (below 0.88 M) and an inhibition at higher amounts. The following marked decay of enzyme activity with time is related to spectroscopically detectable changes. Temperature influences both kinetic and structural aspects of the process and facilitates guanidine action.

The kinetics of concurrent instantaneous and time dependent inhibition of alkaline phosphatase by urea and related compounds.

Abstract: Urea, thiourea and guanidine-HCl greatly inhibit bone Alkaline Phosphatase activity. The inhibition displays saturation kinetics, fitting a model for the reaction sequence in which formation of complexes with increasing affinity occurs. The time dependent inactivation by urea and guanidine follows pseudo-first order kinetics, while thiourea behaviour is better described by a biexponential equation. The pH variation strongly affects the activity, the instantaneous inhibition and the time dependent inactivation. At the pH optimum the three compounds display their strongest effect. Data analysis suggests a three-stage model for the kinetics of Alkaline Phosphatase inhibition by urea and related compounds, involving a consecutive binding process with several sites of the protein and the production of different and interchanging inhibitor-enzyme complexes, leading to irreversibly inactivated forms.

Oleaginous pharmaceutical and cosmetic foam

Abstract: The invention relates to stable oleaginous cosmetic or therapeutic foam compositions containing certain active agents, having unique therapeutic properties and methods of treatment using such compositions. The foamable composition includes at least one solvent selected from a hydrophobic solvent, a silicone oil, an emollient, a co-solvent, and mixtures thereof, wherein the solvent is present at a concentration of about 70% to about 96.5% by weight of the total composition, at least a non-ionic surface-active agent at a concentration of about 0.1% to less than about 10% by weight of the total composition; at least one gelling agent at a concentration of about 0.1% to about 5% by weight of the total composition; a therapeutically effective amount of at least one active agent; and at least one liquefied or compressed gas propellant, at a concentration of about 3% to about 25% by weight of the total composition.

Foamable vehicle and pharmaceutical compositions thereof

Abstract: A hygroscopic pharmaceutical composition includes at least one hygroscopic substance at a concentration sufficient to provide an Aw value of at least 0.9 and an antiinfective agent. A foamble pharmaceutical carrier includes about 50% to about 98% of a polar solvent selected from the group consisting of a polyol and PEG; 0% to about 48% of a secondary polar solvent; about 0.2% to about 5% by weight of a surface-active agent; about 0.01% to about 5% by weight of at least one polymeric agent; and a liquefied or compressed gas propellant at a concentration of about 3% to about 25% by weight of the total composition.

Penetrating pharmaceutical foam

Abstract: The invention relates to an alcohol-free cosmetic or pharmaceutical foam composition comprising water, a hydrophobic solvent, a surface-active agent, a gelling agent, an active component selected from the group of urea, hydroxy acid and a therapeutic enhancer and a propellant. The foam further comprises active agents and excipients with therapeutic properties having enhanced skin penetration.

Antibiotic kit and composition and uses thereof

Abstract: The present invention relates to a therapeutic kit to provide a safe and effective dosage of an antibiotic agent, including an aerosol packaging assembly including: a container accommodating a pressurized product; and an outlet capable of releasing the pressurized product as a foam, wherein the pressurized product comprises a foamable composition including: an antibiotic agent; at least one organic carrier selected from the group consisting of a hydrophobic organic carrier, an organic polar solvent, an emollient and mixtures thereof, at a concentration of about 2% to about 50% by weight, a surface-active agent, about 001% to about 5% by weight of at least one polymeric additive selected from the group consisting of a bioadhesive agent, a gelling agent, a film forming agent and a phase change agent, water; and liquefied or compressed gas propellant at a concentration of about 3% to about 25% by weight of the total composition

Non-flammable insecticide composition and uses thereof

Abstract: The present invention provides a safe and effective insecticide composition suitable for treating a subject infested with a parasitic anthropode or to prevent infestation by an arthropod. The insecticide composition is a foamable composition, including a first insecticide; at least one organic carrier selected from a hydrophobic organic carrier, a polar solvent, an emollient and mixtures thereof, at a concentration of about 2% to about 5%, or about 5% to about 10%; or about 10% to about 20%; or about 20% to about 50% by weight; about 0.1% to about 5% by weight of a surface-active agent; about 0.01% to about 5% by weight of at least one polymeric agent selected from a bioadhesive agent, a gelling agent, a film forming agent and a phase change agent; and (5) a liquefied or compressed gas propellant at a concentration of about 3% to about 25% by weight of the total composition.