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Background: The calcium-binding 2EF-hand protein Phl p 7 from timothy grass pollen is a highly cross-reactive pollen pan-allergen that can induce severe clinical symptoms in allergic patients. Recently, a human monoclonal Phl p 7-specific IgG4 antibody (mAb102.1F10) was isolated from a patient who had received grass pollen-specific immunotherapy (SIT). Methods: We studied epitope specificity, cross-reactivity, affinity and cross-protection of mAb102.1F10 towards homologous calcium-binding pollen allergens. Sequence comparisons and molecular modelling studies were performed with ClustalW and SPADE, respectively. Surface plasmon resonance measurements were made with purified recombinant allergens. Binding and cross-reactivity of patients' IgE and mAb102.1F10 to calcium-binding allergens and peptides thereof were studied with quantitative RAST-based methods, in ELISA, basophil activation and IgE-facilitated allergen presentation experiments. Results: Allergens from timothy grass (Phl p 7), alder (Aln g 4), birch (Bet v 4), turnip rape (Bra r 1), lamb's quarter (Che a 3) and olive (Ole e 3, Ole e 8) showed high sequence similarity and cross-reacted with allergic patients' IgE. mAb102.1F10 bound the C-terminal portion of Phl p 7 in a calcium-dependent manner. It cross-reacted with high affinity with Ole e 3, whereas binding and affinity to the other allergens were low. mAb102.1F10 showed limited cross-inhibition of patients' IgE binding and basophil activation. Sequence comparison and surface exposure calculations identified three amino acids likely to be responsible for limited cross-reactivity. Conclusions: Our results demonstrate that a small number of amino acid differences among cross-reactive allergens can reduce the affinity of binding by a SITinduced IgG and thus limit cross-protection. [ABSTRACT FROM AUTHOR]

Background Group 5 allergens are small proteins that consist of two domains. They belong to the most potent respiratory allergens. Objective To determine the binding sites and to study allergic patients' IgE recognition of the group 5 allergen (Phl p 5) from timothy grass pollen using human monoclonal IgE antibodies that have been isolated from grass pollen allergic patients. Methods Using recombinant isoallergens, fragments, mutants and synthetic peptides of Phl p 5, as well as peptide-specific antibodies, the interaction of recombinant human monoclonal IgE and Phl p 5 was studied using direct binding and blocking assays. Cross-reactivity of monoclonal IgE with group 5 allergens in several grasses was studied and inhibition experiments with patients' polyclonal IgE were performed. Results Monoclonal human IgE showed extensive cross-reactivity with group 5 allergens in several grasses. Despite its small size of 29 kDa, four independent epitope clusters on isoallergen Phl p 5.0101, two in each domain, were recognized by human IgE. Isoallergen Phl p 5.0201 carried two of these epitopes. Inhibition studies with allergic patients' polyclonal IgE suggest the presence of additional IgE epitopes on Phl p 5. Conclusions & Clinical Relevance Our results reveal the presence of a large number of independent IgE epitopes on the Phl p 5 allergen explaining the high allergenic activity of this protein and its ability to induce severe allergic symptoms. High-density IgE recognition may be a general feature of many potent allergens and form a basis for the development of improved diagnostic and therapeutic procedures in allergic disease. [ABSTRACT FROM AUTHOR]

Community-Based Research (CBR) is rapidly gaining recognitions as an important tool in addressing complex environmental, health and social problems. However, little is known about the Canadian CBR context. A web-based survey including 25 questions was circulated on listservs and via targeted e-mails to investigate the status of CBR in Canada. Univariate and bivariate statistical analyses were performed to examine variables and relationships of interest. Our sample included a cross-section of CBR community and academic practitioners (n = 308). Respondents reported a wide range of project foci, experience, operating budgets and reasons for engaging in their last CBR endeavor. Academic partners were perceived to be most involved at all stages of the research process except dissemination. Service providers were also perceived as being very involved in most stages of research. Community members were substantially less engaged. High levels of satisfaction were reported for both CBR processes and outcomes. Respondents reported a number of positive outcomes as a result of their research endeavors, including changes in both agency and government policies and programs. Our study shows that CBR practitioners are engaged in research on a wide array of Canadian health and social issues that is making a difference. Finding appropriate levels of participation for community members in CBR remains an ongoing challenge. [ABSTRACT FROM AUTHOR]

Background: Globally, half of all new HIV infections occur among youth under 25. As of June 30, 2002, more than 13,000 youth and young adults had tested positive for HIV in Canada. Despite this prevalence, there is a lack of resources for Canadian HIV-positive youth.Objective: To investigate what can be done to better support the needs of HIV-positive youth in Canada.Methods: A community-based participatory research approach was adopted. Thirty-four qualitative in-depth semi-structured interviews were conducted with youth (ages 12-24) living with HIV in Ontario. A stakeholder group of youth living with HIV, professionals and researchers collaboratively analyzed the data for emerging themes.Results: When asked about areas in their lives where youth needed support, three major themes emerged: 1) Personal feelings about HIV: Youth identified a wide range of emotional response to their HIV status; however feelings of isolation, loneliness and hopelessness were dominant. 2) Barriers to full participation in society: Youth described a number of social and structural barriers to their full participation in society. 3) Specific support needs: Youth had difficulty accessing appropriate support services; they had very mixed feelings about both youth- and AIDS-serving organizations.Interpretation: The youth we interviewed are interested in targeted programs, have difficulty accessing appropriate resources and would benefit greatly from increased social support. Specialized health and support services that are developmentally appropriate may be necessary. Where specialized services do exist, more research may be necessary to understand why they are underutilized and/or perceived as inappropriate. While this was a small exploratory study, our data suggest that better supporting the needs of HIV-positive youth might directly benefit this vulnerable population. [ABSTRACT FROM AUTHOR]

A patient with an abnormal cardiac silhouette on chest X-ray was studied by fast cardiovascular computed tomography (cine CT). The location of epicardial pacing electrodes and their relationship to myocardial wall motion abnormalities were examined. This eliminated the need for cardiac catheterization. [ABSTRACT FROM AUTHOR]