RESUMO
Adsorption of pepsin by gibbsite and boehmite, non-acid-reactive forms of aluminum hydroxide, was observed and related to the surface area of the adsorbent. Adsorption was pH dependent, with maximum adsorption occurring between pH 2.7-3.3 for gibbsite and pH 2.7-4.3 for boehmite. Electrostatic attraction was an important adsorption mechanism at the pH conditions encountered in the GI tract; the isoelectric point of pepsin was approximately 1, giving it a negative charge, and the point of zero charge for the adsorbents was greater than 9, giving them a positive charge. However, the pH-adsorption profile can not be fully explained by electrostatic considerations. Desorption studies indicate the importance of specific adsorption because pepsin was not desorbed by washing with acidified water, but was partly desorbed by exchange with phosphate. The IR spectrum of adsorbed pepsin also suggested that specific adsorption of pepsin occurred through anionic ligand exchange involving carboxylate groups of pepsin and surface aluminum ions.
Assuntos
Hidróxido de Alumínio/análise , Pepsina A/análise , Adsorção , Animais , Fenômenos Químicos , Físico-Química , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Mucosa Intestinal/enzimologia , Fosfatos , Espectrofotometria Infravermelho , Suínos , TermodinâmicaRESUMO
The percutaneous suprapubic bladder catheter has become an important tool for the urologist because of its efficacy, simplicity and wide range of applications. A case of intestinal obstruction secondary to percutaneous cystotomy with the Bonanno suprapubic bladder drainage catheter is reported.