RESUMO
BACKGROUND & OBJECTIVES: Infection by Salmonella Typhimurium is one of the leading causes of intestinal dysfunction, however the underlying mechanism of this effect is largely unknown. Hence the effect of enterotoxin secreted by Salmonella Typhimurium-(S-LT) was studied on D-glucose absorption and brush border enzymes in rabbit ileum. mRNA levels encoding these proteins were also analysed. METHODS: Adult male New Zealand white rabbits were used. The polymyxine B extract of enterotoxin obtained from Salmonella Typhimurium was tested for the presence of enterotoxicity by rabbit ileal loop test. D-glucose uptake by ileal tissue was measured by the tissue accumulation method. Intestinal brush border membranes were isolated and the effect of S-LT on various brush border enzymes studied. RESULTS: S-LT significantly inhibited (P < 0.01) the absorption of Na+ dependent D-glucose uptake but had no effect on Na+ independent sugar uptake in rabbit ileum. The activities of brush border sucrase (72% P < 0.001) and lactase (47% P < 0.01) and alkaline phosphatase (43% P < 0.01) were also significantly reduced in infected animals as compared to the controls. Northern blot analysis revealed that mRNA levels encoding Na+ glucose co-transporter (SGLT1), brush border lactase and sucrase activities were unaffected in Salmonella infected rabbit ileal loops. INTERPRETATION & CONCLUSION: The findings suggest that the intestinal dysfunctions observed in Salmonella infection are unrelated to mRNA expression encoding Na+ glucose co-transporter and brush border enzyme proteins in rabbit ileum.
Assuntos
Animais , Toxinas Bacterianas/toxicidade , Transporte Biológico Ativo/efeitos dos fármacos , Endotoxinas/toxicidade , Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Íleo/efeitos dos fármacos , Absorção Intestinal/efeitos dos fármacos , Masculino , Glicoproteínas de Membrana/genética , Microvilosidades/efeitos dos fármacos , Proteínas de Transporte de Monossacarídeos/genética , Coelhos , Salmonelose Animal/genética , Salmonella typhimurium/patogenicidade , Transportador 1 de Glucose-SódioRESUMO
Hematoporphyrin derivative, a drug used in the photodynamic therapy of solid tumours was synthesized in the laboratory and was called Hpd(L). Physico-chemical and biological properties of this drug have been compared with Photofrin II, the commercially available drug. Both Hpd(L) and Photofrin II possess similar properties qualitatively. Quantitatively, Hpd(L) was half as active as Photofrin II in its efficacy in causing photodynamic cytotoxicity or in the optical densities at the absorption peaks. These differences could be due to the differences in the compositions. Hpd(L) is a non-purified complex mixture of a number of porphyrin derivatives whereas Photofrin II is a relatively purer compound consisting of di- and tri-hematoporphyrins linked through ether or ester bonds. In vitro cellular uptake and retention of these drugs has been found to be a passive process not involving energy expenditure. pH and temperature of the incubation media have been found to profoundly influence these processes, while a complex relation seems to exist between physiological state of a cell and accumulation of these photosensitizers.
Assuntos
Animais , Antimetabólitos/farmacologia , Transporte Biológico Ativo/efeitos dos fármacos , Linhagem Celular , Cricetinae , Éter de Diematoporfirina/química , Derivado da Hematoporfirina/química , Concentração de Íons de Hidrogênio , Cinética , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , TemperaturaRESUMO
Vatharasavangam (VRV) is a hypoglycemic drug mentioned in the Siddha Literature. Previous studies showed that VRV therapy brings down the blood glucose levels in the hyperglycemic rabbits. The present intestinal perfusion studies with labelled glucose indicate that the blood glucose homeostatis in VRV treated animals is brought about by a significant reduction in the rate of glucose absorption in the intestine. Further an enhanced incorporation of 14C glucose into tissue glycogen is observed in the VRV treated rabbits when compared to the hyperglycemic rabbits.
Assuntos
Animais , Transporte Biológico Ativo/efeitos dos fármacos , Glicemia/metabolismo , Glucose/metabolismo , Hiperglicemia/sangue , Hipoglicemiantes/farmacologia , Absorção Intestinal/efeitos dos fármacos , Masculino , Coelhos , Distribuição TecidualAssuntos
Animais , Transporte Biológico Ativo/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Coração/efeitos dos fármacos , Isoproterenol/farmacologia , Masculino , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Perexilina/farmacologia , Piperidinas/farmacologia , Ratos , Ratos Endogâmicos , Rubídio/metabolismoRESUMO
The effect of sodium on p-aminohippurate (PAH) transport kinetics was studied in isolated rat kidney slices in an attempt to define the role of sodium ion in renal organic acid transport. 1. In normally metabolizing renal slices, Na+ increased the Vmax of PAH influx without changing the Michaelis constant (Km). On the other hand, the effIux of preaccumulated PAH was reduced as the Na+ concentration increased. 2. In metabolically impaired renal slices, Na+ had no apparent effect on the influx and efflux of PAH. These results may indicate that Na+ is important for the energy transducing reaction in the PAH transport process.