RESUMEN
Modified laponites and synthetic saponites are used as precursors for the preparation of poly(epsilon-caprolactone) (PCL)/clay nanocomposites. The structure and dynamics of species intercalated in the modified clays and the corresponding nanocomposites are characterized by X-ray diffraction and magic-angle spinning NMR. The influence of the headgroup, the hydrocarbon chain length, and the loading of the surfactant on the nanocomposite formation are discussed. The yield of PCL intercalation is related to the probability of direct polymer-clay interactions and to the size of the clay platelets. Relaxation times in the laboratory and rotating frames that allow characterization of fast and slow molecular dynamics in these systems are discussed, showing a motional heterogeneity of the intercalated species.
RESUMEN
Cytotoxic T lymphocytes (CTL) lyse virus-infected target cells by secreting the pore-forming effector molecule, perforin. Perforin-mediated cell death appears to be a major mechanism in viral clearance but its role in regulating immune responses in vivo is unclear. In this report, we show that following immunization with influenza viral antigens, perforin-deficient mice generated about 100-fold greater serum antibody responses than wild-type mice. Further, immune spleen cells from perforin knock-out mice secreted over 10-fold more IFN-gamma following in vitro restimulation than immune spleen cells from control mice. Finally, there were over 10-fold more IFN-gamma-secreting cells in cultures from perforin-deficient mice than those from control mice, suggesting that the enhanced cytokine release by T cells from perforin-deficient mice is due to an increase in the effector cell pool. Collectively, these results suggest that perforin-mediated effector function is required in the down-regulation of the immune response by way of limiting antigen-presenting cell function.
Asunto(s)
Anticuerpos Antivirales/biosíntesis , Antígenos Virales/administración & dosificación , Citocinas/biosíntesis , Virus de la Influenza A/inmunología , Glicoproteínas de Membrana/deficiencia , Animales , Anticuerpos Antivirales/sangre , Células Presentadoras de Antígenos/inmunología , ISCOMs/administración & dosificación , Inmunización , Técnicas In Vitro , Interferón gamma/biosíntesis , Interleucina-5/biosíntesis , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Perforina , Proteínas Citotóxicas Formadoras de Poros , Bazo/citología , Bazo/inmunología , Linfocitos T Citotóxicos/inmunología , Vacunas Virales/administración & dosificaciónRESUMEN
Basic hemostasis and fibrinolysis parameters have been analysed in the group of 35 patients with obliterative atherosclerosis and in 41 patients with diabetes mellitus treated with intra-arterial ozone in concentration of O2/O3 54 micrograms/cm3 O3. Assayed parameters were within normal values. However, a tendency to decreased blood coagulation following ozone therapy was more pronounced in patients with obliterative atheromatosis, than in these with diabetes mellitus.