32 research outputs found

    Reduced Expression of the Vesicular Acetylcholine Transporter and Neurotransmitter Content Affects Synaptic Vesicle Distribution and Shape in Mouse Neuromuscular Junction

    Get PDF
    In vertebrates, nerve muscle communication is mediated by the release of the neurotransmitter acetylcholine packed inside synaptic vesicles by a specific vesicular acetylcholine transporter (VAChT). Here we used a mouse model (VAChT KDHOM) with 70% reduction in the expression of VAChT to investigate the morphological and functional consequences of a decreased acetylcholine uptake and release in neuromuscular synapses. Upon hypertonic stimulation, VAChT KDHOM mice presented a reduction in the amplitude and frequency of miniature endplate potentials, FM 1-43 staining intensity, total number of synaptic vesicles and altered distribution of vesicles within the synaptic terminal. In contrast, under electrical stimulation or no stimulation, VAChT KDHOM neuromuscular junctions did not differ from WT on total number of vesicles but showed altered distribution. Additionally, motor nerve terminals in VAChT KDHOM exhibited small and flattened synaptic vesicles similar to that observed in WT mice treated with vesamicol that blocks acetylcholine uptake. Based on these results, we propose that decreased VAChT levels affect synaptic vesicle biogenesis and distribution whereas a lower ACh content affects vesicles shape

    Empowerment and advocacy: reflections on action research with Bangladeshi and Pakistani families who have children with severe disabilities

    No full text
    The concepts of empowerment and advocacy, and how they impinge on power relationships for service providers working with black and Asian communities, are explored through the findings of a 20-month project carried out between 2000 and 2001 with 19 Pakistani and Bangladeshi families who have children with severe disabilities in Birmingham. This action research project evaluated an advocacy project designed to improve the quality of life for Pakistani and Bangladeshi families with at least one child with severe disabilities. The objectives included improving access to resources, services, information and support in ways which were non-stigmatising, and which were sensitive to the particular needs of the children and their carers. The present paper discusses four main themes: (1) advocacy and empowerment in practice; (2) issues of the efficacy of advocacy and of consultation within advocacy; (3) individual empowerment versus the families' needs; and (4) cultural and gender issues which emerged from the analysis of the study. The authors identify features of empowerment which must be addressed in advocacy services which are sensitive to ethnic differences. These issues must be addressed if services are to reap their potential to make a positive impact on the lives of the most vulnerable and powerless members of the community

    Zfx facilitates tumorigenesis caused by activation of the hedgehog pathway

    No full text
    The Hedgehog (Hh) signaling pathway regulates normal development and cell proliferation in metazoan organisms, but its aberrant activation can promote tumorigenesis. Hh-induced tumors arise from various tissues and they may be indolent or aggressive, as is the case with skin basal cell carcinoma (BCC) or cerebellar medulloblastoma, respectively. Little is known about common cell-intrinsic factors that control the development of such diverse Hh-dependent tumors. Transcription factor Zfx is required for the self-renewal of hematopoietic and embryonic stem cells, as well as for the propagation of acute myeloid and T-lymphoblastic leukemias. We report here that Zfx facilitates the development of experimental BCC and medulloblastoma in mice initiated by deletion of the Hh inhibitory receptor Ptch1. Simultaneous deletion of Zfx along with Ptch1 prevented BCC formation and delayed medulloblastoma development. In contrast, Zfx was dispensable for tumorigenesis in a mouse model of glioblastoma. We used genome-wide expression and chromatin-binding analysis in a human medulloblastoma cell line to characterize direct, evolutionarily conserved targets of Zfx, identifying Dis3L and Ube2j1 as two targets required for the growth of the human medulloblastoma cells. Our results establish Zfx as a common cell-intrinsic regulator of diverse Hh-induced tumors, with implications for the definition of new therapeutic targets in these malignancies
    corecore