ABSTRACT
The influence of adding different polysaccharides (locust bean gum, LBG; methyl cellulose, MC; and carboxymethyl cellulose, CMC) to gluten-based biodegradable polymeric materials was assessed in this work. Gluten/polysaccharide/plasticiser bioplastics were prepared at different polysaccharide concentrations (0-4.5%) and pH values by mixing in a two-blade counter-rotating batch mixer (at 25 °C under adiabatic conditions) and thermomoulding at 9MPa and 130 °C. Bioplastic probes were evaluated through dynamic mechanical thermal analysis, tensile strength and water absorption capacity tests. Results pointed out that a moderate enhancement of the network structure may be achieved by adding polysaccharide at a pH close to the protein isoelectric point (pH 6), which also conferred a further thermosetting capacity to the system. Moreover, the addition of MC and CMC was found to significantly enhance material elongation properties. However, the presence of charges induced by pH leaded to a higher incompatibility between the polysaccharide and protein domains forming the composite. The pH value played a relevant role in the material water absorption, which significantly increased under acidic or basic conditions (particularly at pH 3).
Subject(s)
Biodegradable Plastics/chemistry , Glutens/chemistry , Polysaccharides/chemistry , Carboxymethylcellulose Sodium/chemistry , Galactans/chemistry , Hydrogen-Ion Concentration , Mannans/chemistry , Methylcellulose/chemistry , Plant Gums/chemistry , Tensile Strength , Water/chemistryABSTRACT
Negative pressure pulmonary edema is a complication, described since 1977, caused by upper airway obstruction in both children and adults. Although its aetiopathogeny is multifactorial, especially outstanding is excessive negative intrathoracic pressure caused by the forced spontaneous inspiration of a patient against a closed glottis, that causes high arteriole and capillary fluid pressures that favor transudation into the alveolar space The resulting pulmonary edema can appear a few minutes after the obstruction of the airway or in a deferred way after several hours. The clinical manifestations are potentially serious, but normally respond well to treatment with supplemental oxygen, positive pressure mechanical ventilation and diuretics. Diagnostic suspicion is important for acting promptly. We report three clinical cases with acute negative pressure pulmonary edema.
Subject(s)
Pulmonary Edema , Adolescent , Adult , Airway Obstruction/complications , Female , Humans , Male , Middle Aged , Pressure , Pulmonary Edema/diagnosis , Pulmonary Edema/etiology , Pulmonary Edema/therapyABSTRACT
El edema agudo pulmonar por presión negativa esuna complicación descrita desde 1977 tras la obstrucciónde la vía aérea respiratoria, tanto en niños comoen adultos. Aunque su etiopatogenia es multifactorial,destaca especialmente la excesiva presión intratorácicanegativa causada por la inspiración forzada espontáneade un paciente con la glotis cerrada, que resultaen trasudación de líquido de los capilares pulmonareshacia el espacio alveolointersticial. El edema pulmonarresultante puede aparecer en pocos minutos tras laobstrucción de la vía aérea o de forma diferida al cabode varias horas. Este cuadro clínico es potencialmentegrave, pero habitualmente responde bien al tratamientocon oxigenoterapia, ventilación mecánica a presiónpositiva y diuréticos. Es importante el diagnóstico desospecha para adecuar el tratamiento con presteza.Presentamos nuestra experiencia en 3 casos clínicoscon edema agudo pulmonar por presión negativa
Negative pressure pulmonary edema is a complication, ;;described since 1977, caused by upper airway ;;obstruction in both children and adults. ;;Although its aetiopathogeny is multifactorial, especially ;;outstanding is excessive negative intrathoracic ;;pressure caused by the forced spontaneous inspiration ;;of a patient against a closed glottis, that causes ;;high arteriole and capillary fluid pressures that favor ;;transudation into the alveolar space The resulting ;;pulmonary edema can appear a few minutes after the ;;obstruction of the airway or in a deferred way after ;;several hours. The clinical manifestations are potentially ;;serious, but normally respond well to treatment ;;with supplemental oxygen, positive pressure ;;mechanical ventilation and diuretics. Diagnostic suspicion ;;is important for acting promptly. We report ;;three clinical cases with acute negative pressure pulmonary ;;edema
