Search results for "acids"
showing 10 items of 3520 documents
Photo-Cross-Linked Hydrogels with Polysaccharide−Poly(amino acid) Structure: New Biomaterials for Pharmaceutical Applications
2006
The aim of this work has been the preparation and characterization of novel hydrogels with polysaccharide-poly(amino acid) structure having suitable physicochemical properties for pharmaceutical applications. In the first step, hyaluronic acid (HA) and alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) have been derivatized with methacrylic anhydride (AMA), thus obtaining HA-AMA and PHM derivatives, respectively. In the second step, aqueous solutions of both these derivatives have been irradiated at 313 nm to obtain chemical hydrogels. The hydrogel obtained by irradiating for 15 min an aqueous solution containing 4% w/v of HA-AMA and 4% w/v of PHM resulted in the highest yield. Its swe…
Enzymatically hydrolyzed low-density lipoprotein modulates inflammatory responses in endothelial cells
2009
SummaryThere is evidence that low-density lipoprotein (LDL) is modified by hydrolytic enzymes,and that the product (E-LDL) induces selective production of interleukin 8 (IL-8) in endothelial cells. Since nuclear factor-kappaB (NF-κB) is a major regulator of IL-8 transcription, we studied its activation in endothelial cells treated with E-LDL. Unexpectedly,the modified lipoprotein not only failed to activate NF-κB, but completely blocked its activation by tumour necrosis factor-alpha (TNF-α) in EA.hy926-cells, as assessed by electrophoretic mobility shift assays and immunofluorescence. Inhibition occurred upstream of NF-κB translocation, as inhibitor of NF-κB- (IκB)-phosphorylation was suppr…
Synthesis and characterization of modified sulfonated chitosan for beryllium recovery
2019
Abstract A new adsorbent, sulfated crosslinked chitosan (SGCH), has been synthesized for the effective extraction of beryllium ions from their aqueous solutions. In recent times, beryllium extraction has been of great importance because beryllium can be used in many applications such as in nuclear reactor, heat shields, high-technology ceramics, alloys and electronic heat sinks. SGCH has been synthesized by two successive phases. The first is the conversion of chitosan (CH) into non-soluble cross-linked chitosan (GCH) through the interaction between chitosan and glutaraldehyde. The second step is the formation of functional sulfonate groups onto the adsorbent material through the interactio…
Partially Reversible Adsorption of Annexin A1 on POPC/POPS Bilayers Investigated by QCM Measurements, SFM, and DMC Simulations
2005
The kinetics of annexin A1 binding to solid-supported lipid bilayers consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS; 4:1) has been investigated as a function of the calcium ion concentration in the bulk phase. Quartz crystal microbalance measurements in conjunction with scanning force microscopy, fluorescence microscopy, and computer simulations indicate that at a given Ca2+ concentration annexin A1 adsorbs irreversibly on membrane domains enriched in POPS. By contrast, annexin A1 adsorbs reversibly on the POPC-enriched phase, which is composed of single POPS molecules embedded within a POPC matrix. The overall are…
Fermentation of municipal primary sludge: effect of SRT and solids concentration on volatile fatty acid production
2002
Laboratory bench-scale experiments were conducted to investigate the performance of primary sludge fermentation for volatile fatty acids production. Primary sludges from two major wastewater treatment plants located in Valencia (Pinedo and Carraixet) were used. Experiments were performed at solids retention times between 4 and 10 days, and total volatile solids concentrations between 0.6% and 2.8%. Operation at two temperatures (20 degrees C and 30 degrees C) was also checked. Results indicated the importance of feed sludge characteristics on volatile fatty acids yields, being approximately double for the Carraixet wastewater treatment plant sludge than for the Pinedo plant. In both cases, …
Increased resistance to oxidation of betalain-enriched human low density lipoproteins
2003
Betalains are natural pigments recently considered as compounds with potential antioxidative properties. In this work, ex vivo plasma spiking of pure either betanin or indicaxanthin, followed by isolation of low density lipoprotein (LDL), and measurement of its resistance to copper-induced oxidation, has been used to research if these betalains can bind to LDL and prevent oxidation of LDL lipids. When pooled human plasma from 10 healthy volunteers was incubated in the presence of 25-100 microM either betanin or indicaxanthin, incorporation of both compounds in LDL was observed, with a maximum binding of 0.52 +/- 0.08, and 0.51 +/- 0.06 nmoles of indicaxanthin and betanin, respectively, per …
Prostaglandin E(2)-loaded microspheres as strategy to inhibit phagocytosis and modulate inflammatory mediators release.
2008
PGE(2), an arachidonic acid metabolite produced by various type of cells regulates a broad range of physiological activities in the endocrine, cardiovascular, gastrointestinal, and immune systems, and is involved in maintaining the local homeostasis. In the immune system, PGE(2) is mainly produced by APCs and it can suppress the Th1-mediated immune responses. The aim of this study was to develop PGE(2)-loaded biodegradable MS that prolong and sustain the in vivo release of this mediator. An o/w emulsion solvent extraction-evaporation method was chosen to prepare the MS. We determined their diameters, evaluated the in vitro release of PGE(2), using enzyme immunoassay and MS uptake by periton…
Selective labelling of melittin with a fluorescent dansylcadaverine probe using guinea-pig liver transglutaminase
1991
Abstract Melittin, a C-terminal peptide, incorporated the fluorescent probe monodansylcadaverine (DNC) when catalysed by guinea-pig liver transglutaminase and Ca2+, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A 1:1 adduct DNC-melittin was identified in which a single glutamine residue out of two, i.e. Gln25, acts as acyl donor. Incubation of melittin with transglutaminase in the absence of DNC originated high molecular mass complexes indicative that the peptide lysine residue can act as an acyl acceptor. The DNC-melittin was about 3 times more active in the lysis of red cell membranes than native melittin. Fluorescence study of the lab…
Antiepileptic Drugs for the Treatment of Chronic and Episodic Cluster Headache: A Review.
2007
Cluster headache needs to be rapidly diagnosed and effectively managed, as the individual headache attacks that are characteristic of this disorder are excruciatingly painful and debilitating. Preventive therapies are necessary to reduce the frequency of attacks during the cluster period. However, preventive therapy for this disorder is limited by a lack of controlled evidence of efficacy and the potential for systemic toxicity. Recent progress has been made in understanding both the pathophysiological mechanisms underlying cluster headache and the mechanisms of action of the antiepileptic drug class for the treatment of primary headache syndromes. Newly available preliminary clinical trial…
Sensory adaptation of antennae and sex pheromone-mediated flight behavior in male oriental fruit moths (Leptidoptera: Tortricidae) after prolonged ex…
2013
Sensory adaptation has been measured in the antennae of male Grapholita molesta (Busck) after 15 min of exposure to its main pheromone compound (Z)-8-dodecen-1-yl acetate (Z8-12:OAc) at the aerial concentration of 1 ng/m(3) measured in orchards treated with pheromone for mating disruption. Exposing males to this aerial concentration of Z8-12:OAc for 15 min, however, had only a small effect on their ability to orientate by flight to virgin calling females in a flight tunnel. Experiments were undertaken to determine if exposure to the main pheromone compound in combination with the two biologically active minor compounds of this species, (E)-8-dodecen-1-yl acetate (E8-12:OAc) and (Z)-8-dodece…