Subject(s)
Humans , Male , Middle Aged , Endovascular Procedures/methods , Endovascular Procedures , Aortic Valve Stenosis/diagnosis , Aortic Valve Stenosis/therapy , Drug-Eluting Stents/trends , Drug-Eluting Stents , Angiography/methods , Angiography , Brachiocephalic Trunk/surgery , Brachiocephalic TrunkABSTRACT
The mechanism underlying propylene glycol (PG) effects on acyclovir (ACV) penetration through human epidermis were studied. Solvent systems and Carbopol gels containing increasing percentage of PG (from 0% to 70%, w/w) were used. Viscosity studies of both vehicles were carried out to characterise the influence of rheological behaviour. In solvent systems skin permeation values of ACV increase as the concentration of PG increase yielding a maximum enhancement ratio (ER = 10) for 70% PG. The release rate of ACV from gels was determined. Higuchi's model was used to estimate the apparent diffusion coefficient of the drug. These values show a decrease as the content of PG in the vehicle increases; this effect could be attributed to the increase of the viscosity in the diffusional pathway. When gels are used skin permeation values of ACV were smaller than those of the solvent systems. This could be attributed to the network structure created by the polymer that increases the length of the diffusional pathway. The maximum ER (= 6.8) was for Carbopol gel containing 50% PG. Therefore, these gels can be considered candidates for further research to confirm their usefulness as delivery systems for ACV topical formulations.
Subject(s)
Acyclovir/pharmacokinetics , Antiviral Agents/pharmacokinetics , Propylene Glycols/chemistry , Skin Absorption/drug effects , Acrylic Resins , Acyclovir/administration & dosage , Adult , Algorithms , Antiviral Agents/administration & dosage , Excipients , Female , Humans , Hydrogels , Hydrogen-Ion Concentration , In Vitro Techniques , Middle Aged , Polyvinyls , Solubility , Solvents , Thermodynamics , ViscosityABSTRACT
Objetivo. Analizar los resultados del tratamiento endovascular (TEV), valorar especialmente las variaciones producidas en el calibre de los aneurismas de aorta abdominal (AAA) y la evolución de las fugas durante el seguimiento. Pacientes y métodos. 25 pacientes intervenidos de forma electiva mediante dispositivos endovasculares (mayo 1998-diciembre 2000).Seguimiento medio de 11 meses. Se describen los resultados del TEV previos al alta, las variaciones producidas en los aneurismas y la presencia de fugas durante el seguimiento. Resultados. Un 48 per cent de los pacientes intervenidos tenía riesgo quirúrgico ASA III-IV, con una edad media de 71 años. Se empleó la anestesia epidural en un 88 per cent de los casos, y se pudo implantar la endoprótesis en todos los pacientes. La mortalidad fue del 0 per cent. Estancia postoperatoria: 3,2 días. Aparecieron fugas tipo II en tres pacientes en TAC previa al alta, que no precisaron de tratamiento. Durante el seguimiento no se comprobaron variaciones en el cuello ni crecimiento del saco del aneurisma en ningún caso. En 10 pacientes (40 per cent) el diámetro permaneció invariable y en 15 (60 per cent), disminuyó (reducción significativa al 6.º mes).Aparecieron fugas, todas tipo II, en cuatro pacientes (16 per cent). Se comprobó la desaparición de las fugas durante el seguimiento. Conclusiones. El TEV de los aneurismas se acompaña de baja morbimortalidad y reducida estancia postoperatoria. En nuestra serie, se produce una reducción significativa del diámetro máximo del aneurisma a los 6 meses de la implantación del dispositivo. No hemos podido establecer, sin embargo, relación entre la presencia de fugas y la variación en el calibre de los aneurismas (AU)
Subject(s)
Aged , Female , Male , Humans , Calibration , Tomography, Emission-Computed/methods , Angiography/methods , Permeability , Aortic Aneurysm, Abdominal/complications , Aortic Aneurysm, Abdominal/diagnosis , Aortic Aneurysm, Abdominal/therapy , Prostheses and Implants , Prospective Studies , Risk Factors , Anesthesia, Epidural , Aneurysm/diagnosis , Aneurysm , Capillary PermeabilityABSTRACT
Eighty used and 20 new silicone, polyurethane and polyvinylchloride central venous catheters were tested to establish the Young's modulus and the bending stiffness of the catheters and their introducers. The catheters were subjected to longitudinal traction forces and their lengthening measured. Young's modulus and the geometric moment of inertia were then calculated. It is shown that polyurethane catheters show least variation in their elastic characteristics, and that silicone catheters offer least resistance to bending and do not change their elastic properties after use. All catheters were equally unlikely to cause thrombus production if this is related to excessive bending stiffness.
