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1.
The beta-chemokine RANTES (regulated on activation, normal T cell expressed and secreted) suppresses the infection of susceptible host cells by macrophage tropic strains of HIV-1. This effect is attributed to interactions of this chemokine with a 7-transmembrane domain receptor, CCR5, that is required for virus-cell fusion and entry. Here we identify domains of RANTES that contribute to its biological activities through structure-function studies using a new monoclonal antibody, mAb 4A12, isolated from mice immunized with recombinant human RANTES. This monoclonal antibody (mAb) blocked the antiviral activity of RANTES in infectivity assays with HIV-1Bal, and inhibited the mobilization of intracellular Ca2+ elicited by RANTES, yet recognized this chemokine bound to cell surfaces. Epitope mapping using limited proteolysis, reversed phase high-performance liquid chromatography, and mass spectrometry suggest that residues 55-66 of RANTES, which include the COOH-terminal alpha-helical region implicated as the glycosaminoglycan (GAG) binding domain, overlap the determinant recognized by mAb 4A12. This is supported by affinity chromatography studies, which showed that RANTES could be eluted specifically by heparin from a mAb 4A12 immunoaffinity matrix. Removal of cell surface GAGs by enzymatic digestion greatly reduced the ability of mAb 4A12 to detect RANTES passively bound on cell surfaces and abrogated the ability of RANTES to elicit an intracellular Ca2+ signal. Taken together, these studies demonstrate that the COOH-terminal alpha-helical region of RANTES plays a key role in GAG-binding, antiviral activity, and intracellular Ca2+ signaling and support a model in which GAGs play a key role in the biological activities of this chemokine.  相似文献   

2.
Over the past decade only a limited number of public health initiatives have been subjected to systematic monitoring and evaluation and, in many instances, there is growing pressure to estimate which approaches work best for a given level of inputs in order to allocate resources effectively. However, evaluation is very often seen as punitive, and a change in perception is needed to allow evaluation to be owned by all stakeholders in public programs. In the field of HIV/AIDS prevention and care, the first difficulty is that many national AIDS programs lack clearly stated objectives and involve a wide variety of players. These players each have their own guidelines for project/program design, monitoring, and evaluation. The second difficulty relates to the fact that evaluation involves "multiple methods, multiple audiences, multiple funding sources, multiple perspectives, multiple paradigms, multiple roles, and multiple solutions to multiple problems" (Quinn Patton, 1986). To some people, evaluation calls for complex experimental studies while to others it means pausing at the end of an activity to sort out what went well and what went less successfully. This paper examines briefly some of the problems and challenges facing the evaluation of HIV prevention and care and summarizes the approaches adopted by the World Health Organization (WHO) to assist AIDS programs around the world in evaluating their initiatives. The paper also provides an update on the progress of developments, training, and implementation of these approaches.  相似文献   

3.
Occupational medicine in Poland has a long tradition, dating back to the establishment of the first health-care institutions for industrial workers at an early stage of Poland's industrialization. Legal foundations of the industrial health-care system, based on the Soviet model, were enacted in 1953. During its most dynamic period of development (1970s and 1980s) the industrial health-care system provided medical services to about 6 million workers. The process of the political and economic transition in Poland began in 1989, and since 1991 there have been numerous transformations in the structure and function of industrial health services. The present article describes the main stages of the transformation process, occupational health training, research, advisory bodies, and the system for setting of hygienic standards.  相似文献   

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