Search results for "arco"
showing 10 items of 1716 documents
Nuevos modelos y mecanismos moleculares en la enfermedad de Charcot-Marie-Tooth causada por mutaciones en GDAP1
2017
Uno de los genes implicados en la enfermedad de Charcot Marie Tooth, una neuropatia periferica hereditaria, es GDAP1, que codifica para una proteina anclada a la membrana mitocondrial externa. El gen de Drosophila CG4623 es el ortologo de GDAP1 humano, y lo hemos renombrado como Gdap1. La sobreexpresion y silenciamiento de Gdap1, de manera tejido especifica, provoca una degeneracion neuronal y muscular. Ademas, se observan alteraciones en el tamano, morfologia y distribucion mitocondrial. El estudio de diferentes aspectos moleculares indica que los cambios en el estres oxidativo solo ocurren a largo plazo y no son una causa primaria. El estudio metabolomico a traves de la resonancia magneti…
SUL METABOLISMO DEGLI ORGANI DI RATTO PORTATORE DI SARCOMA DA BENZOPIRENE
1955
Free aminoacids were estimated in benzopyrene sarcoma of rats and in some organs of the tumour-bearing rats (brain, heart, muscle, lung, liver, spleen, kidney). In the tumour the content changes according to the growth stage; in the advanced tumour a strong increase of serine-glycine, glutammic acid and treonine is observed. In the organs the free amino acid contents are diminished in the first stages of the tumour growth, while in the advanced stages there is a tendency to an increase with different values according to the organs. The oxidation process in the organ homogenate (with or without substrate addition) varies according to the stage of the tumour growth, more evidently in the org…
Multidentate Polysarcosine-Based Ligands for Water-Soluble Quantum Dots
2016
We describe the synthesis of heterotelechelic polysarcosine polymers and their use as multidentate ligands in the preparation of stable water-soluble quantum dots (QDs). Orthogonally functionalized polysarcosine with amine and dibenzocyclooctyl (DBCO) end groups is obtained by ring-opening polymerization of N-methylglycine N-carboxyanhydride with DBCO amine as initiator. In a first postpolymerization modification step, the future biological activity of the polymeric ligands is adjusted by modification of the amine terminus. Then, in a second postpolymerization modification step, azide functionalized di- and tridentate anchor compounds are introduced to the DBCO terminus of the polysarcosine…
Effect of Heating Time and Temperature on the Chemical Characteristics of Biochar from Poultry Manure
2014
Poultry manure (PM) chars were obtained at different temperatures and charring times. Chemical-physical characterization of the different PM chars was conducted by cross-polarization magic angle spinning (CPMAS) (13)C NMR spectroscopy and thermal analysis. CPMAS (13)C NMR spectra showed that the chemical composition of PM char is dependent on production temperature rather than on production duration. Aromatic and alkyl domains in the PM chars obtained at the lowest temperatures remained unchanged at all heating times applied for their production. The PM char obtained at the highest temperature consisted only of aromatic structures having chemical nature that also appeared invariant with hea…
Polysarcosine-functionalized lipid nanoparticles for therapeutic mRNA delivery
2020
Polysarcosine (pSar) is a polypeptoid based on the endogenous amino acid sarcosine (N-methylated glycine), which has previously shown potent stealth properties. Here, lipid nanoparticles (LNPs) for therapeutic application of messenger RNA were assembled using pSarcosinylated lipids as a tool for particle engineering. Using pSar lipids with different polymeric chain lengths and molar fractions enabled the control of the physicochemical characteristics of the LNPs, such as particle size, morphology, and internal structure. In combination with a suited ionizable lipid, LNPs were assembled, which displayed high RNA transfection potency with an improved safety profile after intravenous injection…
Magnesium, Oxidative Stress, and Aging Muscle
2014
Abstract Magnesium (Mg) deficiency, aside from having a negative impact on the energy production pathways required by the mitochondria to generate ATP, also reduces the threshold antioxidant capacity of the aging organism and its resistance to free-radical damage. Mg acts as an antioxidant against free radical damage of the mitochondria. Chronic Mg deficiency results in excessive production of oxygen-derived free radicals and low-grade inflammation. Chronic inflammation and oxidative stress have been identified as pathogenic factors in several age-related conditions. Aging is often associated with Mg inadequacy, muscle loss, and sarcopenia. Although the importance of magnesium as a determin…
Cylindrical Brush Polymers with Polysarcosine Side Chains: A Novel Biocompatible Carrier for Biomedical Applications
2015
Cylindrical brush polymers constitute promising polymeric drug delivery systems (nanoDDS). Because of the densely grafted side chains such structures may intrinsically exhibit little protein adsorption (“stealth” effect) while providing a large number of functional groups accessible for bioconjugation reactions. Polysarcosine (PSar) is a highly water-soluble, nonionic and nonimmunogenic polypeptoid based on the endogenous amino acid sarcosine (N-methyl glycine). Here we report on the synthesis, characterization and biocompatibility of cylindrical brush polymers with either polysarcosine side chains or poly-l-lysine-b-polysarcosine side chains. The latter leads to block copolypept(o)id based…
Introducing PeptoPlexes: Polylysine-block-Polysarcosine Based Polyplexes for Transfection of HEK 293T Cells
2014
A series of well-defined polypeptide-polypeptoid block copolymers based on the body's own amino acids sarcosine and lysine are prepared by ring opening polymerization of N-carboxyanhydrides. Block lengths were varied between 200-300 for the shielding polysarcosine block and 20-70 for the complexing polylysine block. Dispersity indexes ranged from 1.05 to 1.18. Polylysine is polymerized with benzyloxycarbonyl as well as trifluoroacetyl protecting groups at the ϵ-amine group and optimized deprotection protocols for both groups are reported. The obtained block ionomers are used to complex pDNA resulting in the formation of polyplexes (PeptoPlexes). The PeptoPlexes can be successfully applied i…
Polysarcosine-containing copolymers: Synthesis, characterization, self-assembly, and applications
2018
Although the first polysarcosine (pSar) synthesis by Wesseley et al. was reported almost a century ago, it was only recently that pSar gained broader attention and is considered a potential alternative of poly(ethylene glycol) (PEG). In contrast to polyethers, such as PEG, pSar is a polypeptoid based on the amino acid sarcosine, i.e. N-methylated glycine. As a polymer, pSar combines PEG-like properties, e.g., excellent solubility in water, protein resistance, low cellular toxicity and a non-immunogenic character, while being based on endogenous material. Sarcosine can be obtained in a simple one-step reaction of bromoacetic acid and methylamine, easily transferred into the sarcosine N-(thio…
Synthesis and characterization of bisalkylated polysarcosine-based lipopolymers
2019
The use of PEGylated lipids for the synthesis of stealth liposomes and lipid formulations for nucleic acid delivery has promoted the development of nanoparticle based drugs for cancer therapy, and chronic diseases. Moreover, several other nanomedicines based on these materials have advanced into clinical trails. This enormous success, however, has recently been compromised by the occurrence of immune responses towards PEG, which render pharmacokinetics and can substantially reduce the therapeutic efficiency of drugs. Therefore, alternatives for PEGylated lipids with comparable or even identical solution properties are required. In this work, we report the synthesis of polysarcosine based li…