Search results for "Mandelic Acids"
showing 10 items of 10 documents
Interest of genotyping and phenotyping of drug-metabolizing enzymes for the interpretation of biological monitoring of exposure to styrene
2002
In the field of occupational and/or environmental toxicology, the measurement of specific metabolites in urine may serve to assess exposure to the parent compounds (biological monitoring of exposure). Styrene is one of the chemicals for which biological monitoring programs have been validated and implemented in environmental and occupational medicine. However, inter-individual differences in the urinary excretion exist both for the main end-products (mandelic acid and phenylglyoxylic acid) and for its specific mercapturic acids (phenylhydroxyethylmercapturic acids, PHEMA). This limits to a certain extent the use of these metabolites for an accurate assessment of styrene exposure. In a group…
Nucleophilic benzoylation using a mandelic acid dioxolanone as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of α-hydrox…
2004
The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting alpha-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions.
Effect of controlled-release delivery on the pharmacokinetics of oxybutynin at different dosages: severity-dependent treatment of the overactive blad…
2004
OBJECTIVE To assess the pharmacokinetics of a controlled-release formulation of oxybutynin (OROS®-O, ALZA Corp., Mountain View, CA) at different dosages, compared with immediate-release oxybutynin (IR-O), and to determine the pharmacodynamic properties in the severity-dependent reduction of urge urinary incontinence (UUI). PATIENTS AND METHODS In all, 105 patients were enrolled in this multicentre, randomized, double-blind study. Individual dose titration was used to assess the minimum effective, maximum tolerated or maximum allowed dose of either OROS-O or IR-O. Blood samples were collected during maintenance therapy with frequent sampling to analyse for R-oxybutynin and R-desethyloxybutyn…
Evaluation of antidiuretic hormone before and after long-term treatment with desmopressin in a group of enuretic children
1998
Objective To determine the effect of long-term desmopressin therapy in enuretic patients on the levels of antidiuretic hormone (ADH) during and after the end of therapy. Patients and methods The study comprised 25 outpatients (18 boys and seven girls) aged 8–12 years at the start of therapy and 12–16 years at the end. The morning (08.00 hours) plasma ADH level was determined before treatment (T0) with desmopressin and 2 years after (T1) ending the therapy. Seven of the 25 patients evaluated had monosymptomatic (simple enuresis, SE) and 18 had other symptoms (complex enuresis, CE). Results In the patients with SE, the mean (SD) duration of therapy was 305 (183) days and they were re-evaluate…
Nicotine receptors do not modulate the 3H-noradrenaline release from the isolated rat heart evoked by sympathetic nerve stimulation.
1982
Isolated rat hearts with the right sympathetic nerves attached were perfused at a constant flow rate of 7 ml/min with Tyrode's solution. (-)-3H-Noradrenaline (final concentration 10–13.9 nM) was infused for 10 min to label the noradrenaline stores. After wash-out the sympathetic nerves were stimulated electrically (3 Hz, 180 impulses, 1 ms, 20–30 mA) three times (S1–S3) at intervals of 15 min. 3H-Noradrenaline and its metabolites were determined by liquid scintillation counting according to Graefe et al. (1973). Both, nicotine 50 μM and p-aminophenethyltrimethylammonium (PAPETA) 30 μM, enhanced the 3H-noradrenaline overflow in the absence of nerve stimulation. The effect of PAPETA was bipha…
Reversibility and Diffusion in Mandelythiamin Decarboxylation. Searching Dynamical Effects in Decarboxylation Reactions
2012
Decarboxylation of mandelylthiamin in aqueous solution is analyzed by means of quantum mechanics/molecular mechanics simulations including solvent effects. The free energy profile for the decarboxylation reaction was traced, assuming equilibrium solvation, while reaction trajectories allowed us to incorporate nonequilibrium effects due to the solvent degrees of freedom as well as to evaluate the rate of the diffusion process in competition with the backward reaction. Our calculations that reproduce the experimental rate constant show that decarboxylation takes place with a non-negligible free energy barrier for the backward reaction and that diffusion of carbon dioxide is very fast compared…
Catalytic Asymmetric Addition of Dimethylzinc to α-Ketoesters, Using Mandelamides as Ligands
2006
[reaction: see text] A strategy based on the control of the electron-donating capabilities of the coordinating groups of the ligand has been applied in the catalytic asymmetric addition of organometallic reagents to ketoesters. Mandelamides having deprotonated alcohol and carboxyamido groups catalyzed the addition of dimethylzinc to alpha-ketoesters with good yields and ee (up to 90%).
Short-term benefit of smoking cessation along with glycopirronium on lung function and respiratory symptoms in mild COPD patients: a retrospective st…
2018
Introduction. Tobacco smoke is the leading cause of chronic obstructive pulmonary disease (COPD). Smoking cessation can change the natural history of COPD, as we know from the GOLD guidelines. Little is known about the short-term clinical and functional effects of smoking cessation treatment combined with anti-muscarinic bronchodilators. Objective. To determine whether quitting smoking, obtained by smoking cessation treatment combined with the use of a new long-acting muscarinic antagonist bronchodilator (LAMA), can improve lung function tests and respiratory symptoms more than the use of LAMA alone. Methods. We evaluated, in a retrospective analysis, the functional and clinical data, colle…
Absorption of oxybutynin from vaginal inserts: drug blood levels and the response of the rabbit bladder.
2000
Abstract Objectives. Oxybutynin has been used for treatment of urge urinary incontinence for more than 20 years. However, one of the major problems with its use is uncomfortable anticholinergic side effects that can lead to discontinuation of treatment. Alternative forms of drug administration may reduce side effects and thus improve patient compliance. Methods. A cylinder-shaped, curved silicone elastomer insert containing oxybutynin was anchored in the vagina of female rabbits. The inserts were designed to release oxybutynin at rates of 0.5, 1.0, and 5.0 mg/day, respectively. Blood drug and metabolite levels were monitored for 1 to 7 days and cystometry was carried out after 7 days of tre…
New strategies for medical management of overactive bladder in children.
2011
Purpose of review The medical treatment of children with non-neurogenic overactive bladder syndrome (OAB) is still limited to a small number of drugs approved for use in childhood according to the national regulations of each country. Recent findings Over the last few years, there were several studies on the use of antimuscarinics other than oxybutynin in children, as well as some on the use of extended release oxybutynin and tolterodine and transdermal oxybutynin. It was shown that the combination of two different anticholinergics might be a well tolerated and successful option in children with OAB refractory to monotherapy, as well as administration of a receptor-selective antimuscarinic …