Assuntos
Neoplasias dos Genitais Femininos/enfermagem , Higiene Bucal/enfermagem , Estomatite/enfermagem , Chá , Água , Anti-Infecciosos/administração & dosagem , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Feminino , Humanos , Equipe de Enfermagem , Estomatite/induzido quimicamente , Suíça , Irrigação Terapêutica , Resultado do TratamentoRESUMO
A convenient chromophoric assay for porcine pepsin has been developed using a new synthetic substrate. The sequence of this substrate was chosen based on the known subsite preferences for this enzyme. The peptide contains a phenylalanyl-p-nitrophenylalanine sequence at the reactive site. Cleavage of this bond yields a change in absorbance at 310 nm of between 1700 and 2000 per mole. This allows kinetic data to be obtained readily and accurately. The products of cleavage have been identified by isolation of a peptide fragment by high-performance liquid chromatography. Values of kcat, Km, and kcat/Km of 94 +/- 6 s-1, 0.13 +/- .04 mM, and 815 +/- 210 s-1/mM-1 were obtained at pH 3.0 and 37 degrees C. The peptide is soluble over the pH range from 2 to 7, thus facilitating determination of the pH dependence of the kinetic parameters. The substrate is also valuable in studying the inhibition of pepsin.
Assuntos
Compostos Cromogênicos/síntese química , Endopeptidases/metabolismo , Oligopeptídeos/síntese química , Pepsina A/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Cromatografia Líquida de Alta Pressão , Compostos Cromogênicos/metabolismo , Hidrólise , Cinética , Solubilidade , Espectrofotometria Ultravioleta , Especificidade por Substrato , SuínosRESUMO
Non-suppressible insulin-like activity (NSILA) was determined in 5 dogs before and after hypophysectomy. All NSILA determinations were carried out on serum samples after acidic Sephadex G-50 chromatography by two different assay systems, i.e. a bioassay and a protein binding assay. The levels of NSILA decreased significantly after hypophysectomy and returned to near normal levels after 2 weeks. T3-, T4- and cortisol levels were drastically reduced during the entire period of the experiment. Several GH determinations after hypophysectomy revealed very low levels. Insulin-induced hypoglycaemia failed to provoke a rise of GH levels as late as 4 months after hypophysectomy. These findings indicate that: 1) The pituitary gland cannot be the site of synthesis of NSILA. 2) NSILA concentrations in the dog are maintained at a near normal level in the presence of very low growth hormone and thyroid hormone concentrations, so that these latter hormones do not appear to be the only regulatory factors concerned in NSILA synthesis.
Assuntos
Hipofisectomia , Insulina/sangue , Animais , Cães , Feminino , Hormônio do Crescimento/sangue , Hidrocortisona/sangue , Hipófise/metabolismo , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
Non-suppressible insulin-like activity (NSILA-S) was determined in 5 dogs before and after pancreatectomy and again during insulin therapy. All NSILA-S determinations were carried out on serum samples which were passed over Sephadex G-50 columns equilibrated with 1 M acetic acid. The levels of NSILA-S decreased drastically shortly after pancreatectomy and rose slowly after institution of insulin therapy, to normal levels. During the period of severe diabetes after pancreatectomy the concentration of growth hormone was elevated. These findings indicate that 1) the pancreas cannot be the site of synthesis and release of NSILA-S, 2) NSILA-S levels do not always parallel growth hormone levels and 3) the synthesis and secretion of NSILA-S among other factors is under the control of insulin.
