Usage of EmporeTM membrane in alcoholic media for copper(II)distribution studies

The sorption of copper(II) on a solid, iminodiacetic based, chelating material, the EmporeTM membrane, in alcoholic solutions is considered. Determination of the acid–base properties, kinetic of metal sorption and complexing properties, in solutions with different percentages of ethanol, ranging from 0 to 40% is undertaken. The results are compared with those obtained using the classical iminodiacetic resin Chelex 100 in beads. No significant differences are found in the thermodynamic properties, but the kinetics of the metal sorption on the membrane is slower and a dependence of the process rate with the alcoholic content is observed. In the present investigation, the detection of copper(II) species both in alcoholic Italian distillate “grappa” and in its intermediate product (“flemma”), is carried out by the Resin Titration (RT)method using, as competitive reagent, theEmporeTM membrane. To validate the procedure, synthetic solutions containing different percentages of ethanol are analysed

Iridoids in the flora of Italy .15. Muralioside, an iridoid from Cymbalaria muralis

Cymbalaria muralis subsp. pilosa contains a new iridoid, which we have named muralioside, besides the known antirrhinoside, linarioside, antirrhide, linaride, 8-epiloganic acid and macfadienoside. Muralioside was shown to be 7 beta-hydroxy-harpagide by spectroscopic means and probably arises from the opening of the epoxide ring of antirrhinoside. Following this biogenetic suggestion, the partial synthesis of muralioside from antirrhinoside was carried out by protic acid catalysis. Copyright (C) 1997 Elsevier Science Ltd

Pb(II), Cu(II) and Cd(II) removal through untreated rice husk; thermodynamics and kinetics

The sorption properties of rice husk towards Cu(II), Cd(II) and Pb(II) were studied. The sorption isotherms are described by the Langmuir equation, and Pb(II) shows a higher affinity for rice husk compared to Cu(II) and Cd(II) under the same conditions. The kinetics of sorption obeys to a pseudo second-order equation for all metals. The sorption profiles as a function of the pH were used to characterize the stoichiometry of the sorption reaction. The competition for metal complexation by any ligand in solution is also accounted for. Upon increasing the ionic strength, the sorption curves of Pb(II) move to basic pH; this shift can be explained by considering the effect of nitrate complexes on the free metal ion concentration, since KNO3 is used as the ionic medium. An attempt to employ rice husk in a dynamic system is presented

Adsorption of the Prototype Anionic Anthraquinone, Acid Blue 25, on a Modified Banana Peel: Comparison with Equilibrium and Kinetic Ligand−Receptor Biochemical Data

ABSTRACT: The adsorptive behavior of dye Acid Blue 25 (AB25) on the banana peel is studied with two objectives in view. First, from an environmental point of view, AB25 is considered a model of the anionic dyes, and the banana peel is a quite abundant agricultural waste which can be reused as adsorbent. Second, and on account of the recent research on possible applications of 1-aminoanthraquinone derivatives in pharmacological research, physicochemical studies on the interaction of AB25 anionic prototype and related dyes with different kinds of biomass surfaces can be useful in the basic modeling studies on the antagonist-P2 receptor interactions carried out by different researchers with 1-aminoanthraquinone dyes. A careful analysis of the acid−base properties of the biomass provides the number of weak acid groups, that was found to be 0.288(7) mmol g−1 for modified banana peel in 0.1 M KNO3. An uptake capacity value of 0.215(13) mmol g−1 is obtained when data from batch experiments are fitted to sorption isotherms. Specific surface is calculated and compared with other biosurfaces. Kinetics of the process allows calculating an intraparticle diffusion coefficient, Di, of 0.331(1) × 10−13 m2 s−1. Desorption and column experiments demonstrate the feasibility for an application for AB25 recovery in remediation. Finally, a comparison with thermodynamic and kinetic data from receptor−ligand studies is also carried out

Limbic seizures induce P-glycoprotein in rodent brain: functional implications for pharmacoresistance

The causes and mechanisms underlying multidrug resistance (MDR) in epilepsy are still elusive and may depend on inadequate drug concentration in crucial brain areas. We studied whether limbic seizures or anticonvulsant drug treatments in rodents enhance the brain expression of the MDR gene (mdr) encoding a permeability glycoprotein (P-gp) involved in MDR to various cancer chemotherapeutic agents. We also investigated whether changes in P-gp levels affect anticonvulsant drug concentrations in the brain. Mdr mRNA measured by RT-PCR increased by 85% on average in the mouse hippocampus 3-24 hr after kainic acid-induced limbic seizures, returning to control levels by 72 hr. Treatment with therapeutic doses of phenytoin or carbamazepine for 7 d did not change mdr mRNA expression in the mouse hippocampus 1-72 hr after the last drug administration. Six hours after seizures, the brain/plasma ratio of phenytoin was reduced by 30% and its extracellular concentration estimated by microdialysis was increased by twofold compared with control mice. Knock-out mice (mdr1a/b -/-) lacking P-gp protein showed a 46% increase in phenytoin concentrations in the hippocampus 1 and 4 hr after injection compared with wild-type mice. A significant 23% increase was found in the cerebellum at 1 hr and in the cortex at 4 hr. Carbamazepine concentrations were measurable in the hippocampus at 3 hr in mdr1a/b -/- mice, whereas they were undetectable at the same time interval in wild-type mice. In rats having spontaneous seizures 3 months after electrically induced status epilepticus, mdr1 mRNA levels were enhanced by 1.8-fold and fivefold on average in the hippocampus and entorhinal cortex, respectively. Thus, changes in P-gp mRNA levels occur in limbic areas after both acute and chronic epileptic activity. P-gp alterations significantly affect antiepileptic drugs concentrations in the brain, suggesting that seizure-induced mdr mRNA expression contributes to MDR in epileps