RESUMEN
BACKGROUND: The etiology of motor impairments in preterm infants is multifactorial and incompletely understood. Whether corpus callosum development is related to impaired motor function is unclear. Potential associations between motor-related measures and diffusion tensor imaging (DTI) of the corpus callosum in preterm infants were explored. METHODS: Eight very preterm infants (gestational age of 28-32 weeks) underwent the Hammersmith neonatal neurological examination and DTI assessments at gestational age of 42 weeks. The total Hammersmith score and a motor-specific score (sum of Hammersmith motor subcategories) were calculated. Six corpus callosum regions of interest were defined on the mid-sagittal DTI slice-genu, rostral body, anterior midbody, posterior midbody, isthmus, and splenium. The fractional anisotropy (FA) and mean diffusivity (MD) of these regions were computed, and correlations between these and Hammersmith measures were sought. RESULTS: Anterior midbody FA measures correlated positively with total Hammersmith (rho = 0.929, P = 0.001) and motor-specific scores (rho = 0.857, P = 0.007). Total Hammersmith scores also negatively correlated with anterior midbody MD measures (rho = -0.714, P = 0.047). DISCUSSION: These results suggest the integrity of corpus callosum axons, particularly anterior midbody axons, is important in mediating neurological functions. Greater callosal maturation was associated with greater motor function. Corpus callosum DTI may prove to be a valuable screening or prognostic marker.
Asunto(s)
Cuerpo Calloso/crecimiento & desarrollo , Recien Nacido Prematuro/crecimiento & desarrollo , Destreza Motora/fisiología , Imagen de Difusión Tensora/métodos , Humanos , Recién Nacido , Tamizaje Neonatal/métodos , Examen Neurológico/métodosRESUMEN
The aim of the present work is the synthesis and characterization of polymer materials showing good adhesion, drug loading, and delivery properties, for potential cardiovascular application. In particular, poly(methylmethacrylate-co-acrylic acid) copolymers are prepared in different compositions by a radical polymerization and investigated as potential materials to coat metallic stents and to carry out a local drug release. Films obtained by dissolving the copolymer in an appropriate organic solvent (also loaded with an anti-restenosis drug, such as tacrolimus) are investigated: physicochemical properties, adhesiveness to metallic stent material, and kinetics of drug release in physiological environment are studied.
Asunto(s)
Acrilatos/química , Stents Liberadores de Fármacos , Polímeros/química , Ácidos Polimetacrílicos/química , Stents , Adhesividad , Animales , Química Física/métodos , Sistemas de Liberación de Medicamentos , Diseño de Fármacos , Humanos , Cinética , Ensayo de Materiales , Microscopía de Fuerza Atómica , Tacrolimus/uso terapéuticoRESUMEN
Linear degradable polyurethanes were prepared and proposed for tissue engineering applications. Biocompatible segments were selected for the synthesis to promote their integration with the biological environment. Physicochemical and morphological characterization (SEC, DSC, DMTA, AFM) revealed that the properties of these polymeric systems can be easily tuned by varying the nature and the composition of the constituent segments. In vitro biological assays (citotoxicity, fibroblast adhesion, and proliferation) showed that all polymers are not toxic, promoting the adhesion and proliferation of fibroblast cells, with slight differences depending on the material hydrophilicity.
Asunto(s)
Materiales Biocompatibles/química , Poliuretanos/química , Animales , Biofisica/métodos , Rastreo Diferencial de Calorimetría , Adhesión Celular , Proliferación Celular , Fibroblastos/metabolismo , Ratones , Microscopía de Fuerza Atómica , Modelos Químicos , Células 3T3 NIH , Polímeros/química , Temperatura , Ingeniería de TejidosRESUMEN
At the onset of West syndrome a specific impairment of visual function has been clearly demonstrated, while other aspects of sensorial development, and in particular of the auditory function, have been less studied. The aim of this study was to evaluate auditory function and orienting responses at the onset of West syndrome, and to relate the results with EEG patterns, visual function and neurodevelopmental competence. A prospective multicentric study was performed on 25 successively enrolled infants with West syndrome; all the patients underwent a full clinical assessment, including MRI and video-EEG, visual function and auditory orienting responses (AORs) as well as Griffiths' developmental scales. The whole assessment performed at the onset of spasms (T0) was repeated after two months (T1). AORs resulted significantly impaired both at T0 and T1. At the onset of spasms a highly significant relationship of auditory attention with visual function and neurodevelopmental competence was shown in both cryptogenic and symptomatic forms, but it was no longer present after two months. Our results may suggest a possible pervasive effect of the epileptic disorder on sensory processing, associated to a deficit of neurodevelopment. Although we failed to show a significant correlation between auditory orienting responses and EEG patterns, some evidence seems to support at least partially an influence of the epileptic disorder per se on the genesis of the sensorial impairment. A longer follow up and a larger cohort will be useful for a better clarification of these findings.
Asunto(s)
Atención/fisiología , Electroencefalografía , Audición/fisiología , Espasmos Infantiles/fisiopatología , Visión Ocular/fisiología , Estimulación Acústica/métodos , Femenino , Humanos , Lactante , Imagen por Resonancia Magnética/métodos , Masculino , Estudios RetrospectivosRESUMEN
In the present paper, the covalent immobilisation of the digesting enzyme trypsin has been achieved through photo-immobilisation on a portion of a silica capillary, thus leading to the construction of a capillary electrophoretic (CE)-microreactor for peptide mapping. The CE-microreactor is characterised by being a single piece, thus ensuring no fluidic or electrical leakage. The enzyme was immobilised with a surface density of 15.8 microg/cm(2), the stability was high (80% after 38 days) and the rate of conversion was 0.2 ng/s. On-line protein mapping was tested with proteins of different dimensions, showing competitiveness in terms of time (completed map within 15 min) and exhaustive maps of small proteins. The results of the CE-microreactor and the potential to immobilise biocomponents easily on a desired portion of the capillary indicate further developments towards the construction of a variety of miniaturised enzymatic screening devices for high-throughput screening analysis.
Asunto(s)
Electroforesis Capilar/instrumentación , Mapeo Peptídico/instrumentación , Bradiquinina/química , Enzimas Inmovilizadas/química , Mapeo Peptídico/métodosRESUMEN
Two chimeric proteins, consisting of the B subunit of Escherichia coli heat-labile enterotoxin with different peptides fused to the COOH-terminal ends, have been crystallized and their three-dimensional structure determined. The two extensions correspond to (a) a nonapeptide representing the COOH-terminal sequence of the small subunit of herpes simplex virus type 1 ribonucleotide reductase and (b) a 27-amino acid long peptide, corresponding to the COOH-terminal end of the catalytic subunit (POL) of DNA polymerase from the same virus. Both proteins crystallize in the P41212 space group with one pentameric molecule per asymmetric unit, corresponding to a solvent content of about 75%. The overall conformation of the B subunit pentamer in the two chimeric proteins, which consists of five identical polypeptide chains, is very similar to that in the native AB complex and conforms strictly to 5-fold symmetry. On the contrary, the peptide extensions are essentially disordered: in the case of the nonapeptide, only 5 and 6 amino acids were, respectively, positioned in two monomers, while in the other three only 2 residues are ordered. The extension is fully confined to the surface of the pentamer opposite to the face that interacts with the membrane and consequently it does not interfere with the ability of the B subunit to interact with membrane receptors. Moreover, the conformational flexibility of the two peptide extensions could be correlated to their propensity for proteolytic processing and consequent release of a biologically active molecule into cultured cells.
Asunto(s)
Antivirales/química , Enterotoxinas/química , Escherichia coli/química , Péptidos/farmacología , Simplexvirus/química , Animales , Chlorocebus aethiops , Cristalografía por Rayos X , Técnica del Anticuerpo Fluorescente , Modelos Moleculares , Datos de Secuencia Molecular , Péptidos/química , Conformación Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacología , Simplexvirus/efectos de los fármacos , Células Vero , Proteínas Virales/químicaRESUMEN
Retinoids are quite insoluble and chemically unstable compounds in the aqueous medium, such that natural retinoids need to be bound to specific retinoid-binding proteins to be protected, solubilized and transported in body fluids. All-trans retinoic acid exhibits a relatively high affinity for thyroxine-binding transthyretin in vitro and this protein is a good candidate for the transport of retinoic acid administered as pharmacological or antitumor agent. To define structural features essential for the recognition by transthyretin of a ligand which is structurally unrelated to thyroxine, we have cocrystallized human transthyretin with retinoic acid and determined its structure at 0.18-nm resolution. The retinoid fits into the two chemically identical thyroxine-binding sites, which are located in the central channel that runs through the tetrameric transthyretin. The cyclohexene ring of the bound retinoid is innermost, occupying the same position of the phenolic ring of the bound 3,3'-diiodo-L-thyronine, whereas the carboxylate group, like the same group of the thyroid hormone, participates in an ionic interaction with the Lys15 side chain at the entrance of the channel. Despite the fact that transthyretin was cocrystallized with all-trans-retinoic acid, the isoprene chain of the bound retinoid has been found in a non-extended conformation. This feature, that allows the carboxylate to orient in a manner suitable for ion-pair association with the Lys15 side chain, is attributable to the conversion of all-trans-retinoic acid into cis-isomers or folded conformers. It is concluded that the presence, in an essentially hydrophobic molecular core of the appropriate size, of a negatively charged group at the correct position is a crucial requirement for ligand-transthyretin recognition. Whereas the binding of the ligand has no remarkable consequences for the protein structure, all-trans-retinoic acid undergoes structural changes such as to interact favorably with residues present in the thyroxine-binding sites, resembling roughly the natural ligand.