RESUMEN
A very peculiar case of differential cell response towards polysiloxane surfaces of very similar composition is investigated. Poly(hydroxymethylsiloxane) (PHMS) surfaces treated either by O(2)-plasma or 6 keV Ar(+)-beams have been used to test the adhesion, proliferation and spreading of human fibroblasts. The surface chemical structure and nanomorphology were investigated by means of X-ray photoelectron spectroscopy (XPS), surface free energy measurements and atomic force microscopy (AFM). In spite of the close compositional and morphological similarity of the modified surfaces, the viability of the adhered cells, evaluated by means of optical microscopy and epifluorescence microscopy, was found to be very different in the two cases. The study of the features of the adsorbed protein adlayer on the two types of surfaces was performed by XPS and AFM and indicated that the overall cell behavior is connected to a quite different protein aggregation process, occurring respectively on the plasma- and Ar(+)-modified polysiloxane surfaces. It is suggested that the specific biological response of the modified surfaces is determined by the chemical structure at the nanometric level.
RESUMEN
In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize poly(3-hydroxyalkanoates) (PHAs) from saturated fatty acids with an even number of carbon atoms, from eight to 22, and from oleic acid. In a non-limiting medium, all carbon sources but docosanoic acid supported cell growth and PHA production, with eicosanoic acid giving the highest yield. In magnesium-limiting conditions, higher yields were obtained from sources with up to 16 carbon atoms. Composition was estimated by gas chromatography of methanolyzed samples and (13)C nuclear magnetic resonance. The 3-hydroxyalkanoate units extended from hexanoate to tetradecanoate or tetradecenoate, with octanoate and decanoate as the predominant components. Weight average molecular weights ranged from 78,000 to 316,000. Fast atom bombardment mass spectrometry of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.
Asunto(s)
Poliésteres/química , Poliésteres/metabolismo , Pseudomonas aeruginosa/metabolismo , Cromatografía de Gases , Ácidos Grasos/metabolismo , Sustancias Macromoleculares , Espectroscopía de Resonancia Magnética , Estructura Molecular , Peso Molecular , Pseudomonas aeruginosa/química , Espectrometría de Masa Bombardeada por Átomos VelocesAsunto(s)
Hormona del Crecimiento/uso terapéutico , Síndrome de Turner/terapia , Estatura/efectos de los fármacos , Desarrollo Óseo/efectos de los fármacos , Niño , Quimioterapia Combinada , Etinilestradiol/farmacología , Etinilestradiol/uso terapéutico , Femenino , Hormona del Crecimiento/farmacología , Humanos , Pubertad/efectos de los fármacos , Resultado del TratamientoRESUMEN
Multiple Pterygium Syndrome is a rare autosomal recessive disorder characterized by short stature, multiple pterygium, joint contractures, vertebral fusions and minor facial anomalies. Due to the extreme phenotypic variability of this syndrome many mild cases may be misdiagnosed or not recognized. The importance of an early diagnosis is to provide an adequate follow-up of these children in order to try to prevent many of the clinical problems they may encounter in their life-time.