Polygalacturonic acid (PGA), being the backbone of pectins, governs their aggregation that is widely applied in industry. The PGA aggregation was studied by dynamic and static light scattering within a limited space of sodium polygalacturonate nanoparticles obtained by nanoprecipitation (drop-wise addition of alkaline solution of PGA to an ethanol bath). With increasing buffer's pH from 4.0 to 9.1, the colloids changed their form from elongated to spherical one, as indicated by decreasing the structure-sensitive ratio R_g/R_h from 1.7 to 1.1. Molecular mass-per-unit-length determined in Holtzer coordinates decreased from 5000 to 1600 Da nm^-1 with increasing pH, suggesting partial disintegration of helical bundles due to electrostatic repulsion. Kratky plots also pointed out partial disintegration of the PGA junctions with increasing pH. Nonmonotonic dependence of the colloidal radius of gyration R_g on [NaCl] characterized the osmotic regime characteristic of annealed polyelectrolytes and thus confirmed the star-like structure of junctions.

2011-04-01·Enzyme and Microbial Technology3区 · 工程技术

Bioresponsive systems based on polygalacturonate containing hydrogels

3区 · 工程技术

Article

作者: Alexandra Rollett ; Konstantin P. Schneider ; Andreas Muehlebach ; Andrea Hasmann ; Georg M. Guebitz ; Franz Kaufmann ; Armin Zankel ; Eva Wehrschuetz-Sigl

Polysaccharide acid (PSA) based devices (consisting of alginic acid and polygalacturonic acid) were investigated for the detection of contaminating microorganisms. PSA-CaCl(2) hydrogel systems were compared to systems involving covalent cross-linking of PSA with glycidylmethacrylate (PSA-GMA) which was confirmed with Fourier Transformed Infrared (FTIR) analysis. Incubation of PSA-CaCl(2) and PSA-GMA beads loaded with Alizarin as a model ingredient with trigger enzymes (polygalacturonases or pectate lyases) or bacteria lead to a smoothening of the surface and exposure of Alizarin according to Environmental Scanning Electron Microscopy (ESEM) analysis. Enzyme triggered release of Alizarin was demonstrated for a commercial enzyme preparation from Aspergillus niger and with purified polygalacturonase and pectate lyase from S. rolfsii and B. pumilus, respectively. In contrast to the PSA-CaCl(2) beads, cross-linking (PSA-GMA beads) restricted the release of Alizarin in absence of enzymes. There was a linear relation between release of Alizarin (5-348 μM) and enzyme activity in a range of 0-300 U ml(-1) dosed. In addition to enzymes, both PSA-CaCl(2) and PSA-GMA beads were incubated with Bacillus subtilis and Yersinia entercolitica as model contaminating microorganism. After 72 h, a release between 10 μM and 57 μM Alizarin was detected. For protection of the hydrogels, an enzymatically modified PET membrane was covalently attached onto the surface. This lead to a slower release and improve long term storage stability based on less than 1% release of dye after 21 days. Additionally, this allowed simple detection by visual inspection of the device due to a colour change of the white membrane to orange upon enzyme triggered release of the dye.

2010-02-01·Journal of Cardiovascular Medicine4区 · 医学

‘Orphan drugs’ in cardiology: nadolol and quinidine

4区 · 医学

Article

作者: Pedrinazzi, Claudio ; Inama, Giuseppe ; Durin, Ornella ; Berisso, Massimo Zoni ; Furlanello, Francesco

The recent withdrawal from the market of nadolol (Corgard; Bristol-Myers Squibb, Sermoneta, Italy) and quinidine polygalacturonate (Ritmocor; Malesci, Bagno A Ripoli, Italy) has been causing clinical problems to many cardiologists and patients, frequently leading to discontinuance of an effective and well-tolerated pharmacological treatment. Nadolol is useful in the treatment of severe and refractory arrhythmias, particularly in some genetically determined ion-channel diseases, such as long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia.Quinidine is still used in refractory atrial fibrillation recurrences. Recent studies have demonstrated the clinical efficacy of quinidine in the treatment of rare genetically determined ion-channel diseases at high risk of sudden death, such as Brugada syndrome and short-QT syndrome.We hope that scientific societies can influence healthcare and pharmaceutical institutions, in order to restore the availability of two cardiovascular drugs that are extremely important in the care of arrhythmic patients.

100 项与聚半乳糖醛酸奎尼丁相关的药物交易

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