Search results for "Polyamin"
showing 10 items of 160 documents
ChemInform Abstract: Proton Coordination by Polyamine Compounds in Aqueous Solution
2010
Abstract The present article is concerned with proton transfer reactions in aqueous solution of open-chain, macrocyclic and macropolycyclic or cage compounds having nitrogen atoms as protonation sites in the molecular framework, although several compounds with additional different donors will be considered. The main purpose of this review is to collect some significant examples of proton transfer processes in order to show how the electronic properties and molecular topology of polyamines affect the thermodynamic parameters of their protonation equilibria.
ChemInform Abstract: Fluorescent Chemosensors Containing Polyamine Receptors
2000
Chemosensors have attracted interest in many different scientific fields, such as environmental chemistry, medicine, and the processing and storage of information. These molecular-scale devices have the advantage of working on the same spatial scale as the chemical structures that are responsible for macroscopic behaviour observed in the environment or those associated with health problems. Moreover, they allow the construction of molecular-scale devices for information storage. In this review, we describe a family of chemosensors based on a polyamine receptor and a fluorescent signalling unit. Polyamine receptors are water-soluble ambidentate receptors; they are able to coordinate either m…
Polyamines : études et applications
2008
International audience
Methionine Cycle Rewiring by Targeting miR-873-5p Modulates Ammonia Metabolism to Protect the Liver from Acetaminophen
2022
Drug-induced liver injury (DILI) development is commonly associated with acetaminophen (APAP) overdose, where glutathione scavenging leads to mitochondrial dysfunction and hepatocyte death. DILI is a severe disorder without effective late-stage treatment, since N-acetyl cysteine must be administered 8 h after overdose to be efficient. Ammonia homeostasis is altered during liver diseases and, during DILI, it is accompanied by decreased glycine N-methyltransferase (GNMT) expression and S-adenosylmethionine (AdoMet) levels that suggest a reduced methionine cycle. Anti-miR-873-5p treatment prevents cell death in primary hepatocytes and the appearance of necrotic areas in liver from APAP-adminis…
Polyamines and ripening of photoreceptor outer segments in chicken embryos.
1995
Abstract Polyamines and their related monoacetyl derivatives were studied in rod outer segment (ROS) and cone outer segment (COS) of photoreceptor cells from chick embryo retina during eye development (7th–18th days). Putrescine was found to be necessary, in the second phase of retinogenesis, to sustain both ROS and COS differentiation and, after acetylation, γ-aminobutyric acid synthesis. On the other hand, spermidine and even more spermine intervene in the third phase of development when photoreceptors mature. Moreover, the presence of N1-acetylspermidine already at the 7th day indicates that in the outer segment of photoreceptor cells too, as in the whole retina, putrescine synthesis com…
Märkälujaliimojen määritys pyrolyysi-kaasukromatografi-massaspektrometrillä
2017
Polymeerien, kuten märkälujaliimojen, analysoiminen on ollut nykyisillä menetelmillä erittäin työlästä tai hidasta. Pyrolyysi edustaa kuitenkin menetelmää, jolla esikäsittely ja aika saadaan minimiin. Menetelmässä näyte pilkotaan pienemmiksi yhdisteiksi, jolloin näyte saadaan helpommin analysoitavaan muotoon. Yleisimmin pyrolyysiä käytetään yhdessä kaasukromatografian kanssa. Työn kirjallisessa osassa perehdyttiin yleisimpien märkälujaliimojen valmistukseen, rakenteisiin ja ominaisuuksiin. Kirjallisuuskatsauksessa käytiin myös läpi pyrolyysin periaatteet, sovellukset sekä kartongin ja eräiden märkälujaliimojen pyrolyysituotteet. Lisäksi työssä perehdyttiin typpimäärityksiin. Työn kokeellise…
Polyamino Acid Carriers In Drug Delivery And Their Production Under Good Manufacturing Practice Compliance
2021
Poly(Amino Acids) (PAA)s are biocompatible, biodegradable and multifunctional polymers, which have been effectively used as building blocks in polymer-based delivery carriers for various medical applications. In addition, PAAs are envisaged to achieve a major impact on biomedical areas due to their structural versatility, biocompatibility, water-solubility and the important advances made on the synthetic strategies. Control on polymer chain length and stereochemistry have been one of the major challenges in PAA synthesis over the past years. Their physico-chemical properties can be modulated in terms of the manufacturing process, size, electrostatic charge, conformation, geometry, topology,…
Single hollow fiber SLM extraction of polyamines followed by tosyl chloride derivatization and HPLC determination
2007
Determination of polyamines in biological fluids possesses medical diagnostic relevance. Despite the vast panel of analytical methods developed for polyamines they are not applied in routine clinical usage, mainly due to the time and labor consuming sample preparation step and complicated derivatization procedures. Thus, new simpler methods are needed. This paper describes a single hollow fiber SLM extraction method of polyamines followed by simple pre-column derivatization with tosyl chloride and HPLC-UV analysis. The influence of different parameters such as the extraction time, organic phase composition, acceptor pH, donor pH, acceptor volume, donor volume and stirring speed on the trans…
From isolated 1H-pyrazole cryptand anion receptors to hybrid inorganic-organic 1D helical polymeric anion receptors
2015
We report a novel 1-D helical coordination polymer formed by protonated polyamine 1H-pyrazole cryptands interconnected by Cu2+ metal ions that are able to encapsulate anionic species behaving as a multianion receptor. Switching from a monomeric receptor to a polymeric receptor is activated by metal ions and pH.
Amphoteric, prevailingly cationic L-arginine polymers of poly(amidoamino acid) structure: Synthesis, acid/base properties and preliminary cytocompati…
2013
A linear amphoteric poly(amidoamino acid), L-ARGO7, is prepared by Michael-type polyaddition of L-arginine with N,N′-methylenebisacrylamide. Chain-extension of acrylamide end-capped L-ARGO7 oligomers with piperazine leads to high-molecular-weight copolymers in which L-arginine maintains its absolute configuration. Acid/base properties of L-ARGO7 polymers show isolectric points of ≈10 and positive net average charges per repeating unit at pH = 7.4 from 0.25 to 0.40. These arginine-rich synthetic polymers possibly share some of the unique biological properties of polyarginine cell-permeating peptides. In vitro tests with mouse embryo fibroblasts balb/3T3 clone A31 show that L-ARGO7 polymers a…