1000 resultados para ddc: 153.15
Resumo:
Macrophages and muscle cells are the main targets for invasion of Trypanosoma cruzi. Ultrastructural studies of this phenomenon in vitro showed that invasion occurs by endocytosis, with attachment and internalization being mediated by different components capable of recognizing epi-or trypomastigotes (TRY). A parasitophorus vacuole was formed in both cell types, thereafter fusing with lysosomes. Then, the mechanism of T. cruzi invasion of host cells (HC) is essentially similar (during a primary infection in the abscence of a specific immune response), regardless of wether the target cell is a professional or a non-professional phagocytic cell. Using sugars, lectins, glycosidases, proteinases and proteinase inhibitors, we observed that the relative balance between exposed sialic acid and galactose/N-acetyl galactosamine (GAL) residues on the TRY surface, determines the parasite's capacity to invade HC, and that lectin-mediated phagocytosis with GAL specificity is important for internalization of T. cruzi into macrophages. On the other hand, GAL on the surface to heart muscle cells participate on TRY adhesion. TRY need to process proteolytically both the HC and their own surface, to expose the necessary ligands and receptors that allow binding to, and internalization in the host cell. The diverse range of molecular mechanisms which the parasite could use to invade the host cell may correspond to differences in the available "receptors"on the surface of each specific cell type. Acute phase components, with lectin or proteinase inhibitory activities (a-macroglobulins), may also be involved in T. cruzi-host cell interaction.
Resumo:
We have prepared transgenic mice whose T cells constitutively express a chimeric receptor combining extracellular human IL-4R and intracellular IL-2Rbeta segments. This receptor can transmit IL-2/IL-15-like signals in response to human, but not mouse, IL-4. We used these animals to explore to what extent functional IL-2R/IL-15R expression controls the capacity of T cells to proliferate in response to IL-2/IL-15-like signals. After activation with Con A, naive transgenic CD8+ and CD4+ T cells respond to human IL-4 as well as to IL-2. Without prior activation, they failed to proliferate in response to human IL-4, although human IL-4 did prolong their survival. Thus, IL-2-induced proliferation of activated T cells requires at least one other Ag-induced change apart from the induction of a functional IL-2R. However, a fraction of CD8+CD44high T cells proliferate in human IL-4 without antigenic stimulation or syngeneic feeder cells. In contrast, CD4+CD44high T cells are not constitutively responsive to human IL-4. We conclude that although all transgenic T cells express a functional chimeric receptor, only some CD8+CD44high T cells contain all molecules required for entry into the cell cycle in response to human IL-4 or IL-15.
Resumo:
Vaccines in schistosomiasis using homologous antigens have been studied extensively in experimentally infected mammalian hosts. Vaccines using heterologous antigens have received comparatively less attention. This review summarizes recent work on a heterologous 12 kDa Fasciola hepatica antigenic polypeptide which cross reacts with Schistosoma mansoni. A cDNA has been cloned and sequenced, and the predicted amino acid sequence of the recombinant protein has been shown to have significant (44) identity with a 14 kDa S. mansoni fatty acid binding protein. Thus in the parasitic trematodes fatty acid binding proteins may be potential vaccine candidates. The F. hepatica recombinant protein has been overexpressed and purified and denoted rFh15. Preliminary rFh15 migrates more slowly (i.e. may be slightly larger) than nFh12 on SDS-PAGE and has a predicted pI of 6.01 vs. observed pI of 5.45. Mice infected with F. hepatica develop antibodies to nFh12 by 2 weeks of infection vs. 6 weeks of infection to rFh15; on the other hand, mice with schistosomiasis mansoni develop antibodies to both nFh12 and rFh15 by 6 weeks of infection. Both the F. hepatica and S. mansoni cross-reactive antigens may be cross-protective antigens with the protection inducing capability against both species.
Resumo:
Aquest projecte estudia la implantació d’un sistema de posicionament a l’interior d’un edifici que compti amb una xarxa WiMAX. Per començar, s’analitzaran les característiques principals d’aquesta tecnología, la configuració de la xarxa amb la que treballarem i s’explicaran els mètodes de posicionament existents avui en dia. Més endavant s’estudiaran els aspectes més importants de la nostra aplicació: l’escenari, l’estimació de la distancia i l’estimació de la posició. Finalment, després d’analitzar els resultats de diverses mesures, es dissenyaran tres mètodes pel càlcul de la posició i s’aplicarà el nostre procediment en més de 15 escenaris de posicionament diferents, amb l’objectiu de comparar els resultats i definir quin dels mètodes aconsegueix un posicionament més precís.
Resumo:
Seventeen patients proceeding from the municipality of Rio de Janeiro, Brazil presenting with the cutaneous ulcerative form of American leishmaniasis were treated with one ampoule of pentavalent antimony daily for 30 days. With this regimen the individuals doses varies greatly: from 3.8 mg/kg of body weight to 22.3 mg/kg. After five years, patients receiving either a smaller dose or a bigger one, showed the same therapeutic result: cutaneous scars and no mucosal lesions.
Resumo:
Els pacients diagnosticats de malaltia de Steinert s’intervenen quirúrgicament amb freqüència a causa del gran número de manifestacions clíniques, entre les quals s’hi inclouen trastorns respiratoris, cardíacs, gastrointestinals, oculars i endocrins; el maneig anestèsic d’aquests pacients requereix una atenció especial atenent no només al coneixement de les interaccions farmacològiques sinó també al maneig de les principals complicacions perioperatòries. L’objectiu d’aquest treball va ser el de revisar les històries clíniques dels pacients diagnosticats de malaltia de Steinert controlats pel Servei de Neurologia de l’Hospital Universitari Vall d`Hebron; el registre i la classificació de les principals cirurgies a les quals eren sotmesos així com la determinació de la incidència de complicacions postoperatòries relacionades amb les diferents tècniques anestèsiques.
Resumo:
The use of artificial nest-boxes has led to significant progress in bird conservation and in our understanding of the functional and evolutionary ecology of free-ranging birds that exploit cavities for roosting and reproduction. Nest-boxes and their improved accessibility have made it easier to perform comparative and experimental field investigations. However, concerns about the generality and applicability of scientific studies involving birds breeding in nest-boxes have been raised because the occupants of boxes may differ from conspecifics occupying other nest sites. Here we review the existing evidence demonstrating the importance of nest-box design to individual life-history traits in three falcon (Falconiformes) and seven owl (Strigiformes) species, as well as the extent to which publications on these birds describe the characteristics of exploited artificial nest-boxes in their 'methods' sections. More than 60% of recent publications did not provide any details on nest-box design (e.g. size, shape, material), despite several calls >15 years ago to increase the reporting of such information. We exemplify and discuss how variation in nest-box characteristics can affect or confound conclusions from nest-box studies and conclude that it is of overall importance to present details of nest-box characteristics in scientific publications.
Resumo:
On 17 November 2011, the First Minister and deputy First Minister published the draft Programme for Government 2011-2015 for consultation. IPH recognise that health is influenced by a wide range of social determinants, including economic, biological, environmental and cultural factors such as housing, the environment, income, employment and access to education and health services . Improvements to health can be achieved through a well-designed PfG which addresses the economy, creates safer communities and delivers efficient public services. IPH welcome this opportunity to submit our views to the Northern Ireland Executive on the Draft Programme for Government 2011-15. Key points from the IPH response include: • Northern Ireland has a poor population health status in key areas when compared to other regions in the United Kingdom and in the Republic of Ireland. IPH support and particularly welcome allocation of an increased proportion of the Northern Ireland budget to public health. • IPH endorses the perspective in the PfG that good population health makes a central contribution to economic and social development. However we would welcome greater acknowledgement of the links between social deprivation and health outcomes. • IPH welcomes the adoption of a social determinants of health approach to improving population health and tackling health inequalities which is in line with current health policy and recent policy developments across the United Kingdom and internationally (See report of the Commission on the Social Determinants of Health (CSDH))
Resumo:
Survey of the attitudes of the general public to health and social services