The mature optic nerve cannot regenerate when injured, leaving victims of traumatic nerve damage or diseases such as glaucoma with irreversible visual losses. Recent studies have identified ways to stimulate retinal ganglion cells to regenerate axons part-way through the optic nerve, but it remains unknown whether mature axons can reenter the brain, navigate to appropriate target areas, or restore vision. We show here that with adequate stimulation, retinal ganglion cells are able to regenerate axons the full length of the visual pathway and on into the lateral geniculate nucleus, superior colliculus, and other visual centers. Regeneration partially restores the optomotor response, depth perception, and circadian photoentrainment, demonstrating the feasibility of reconstructing central circuitry for vision after optic nerve damage in mature mammals.
Reprogramming somatic cells from one cell fate to another can generate specific
neurons suitable for disease modeling. To maximize the utility of patient-derived neurons,
they must model not only disease-relevant cell classes but also the diversity of neuronal
subtypes found in vivo and the pathophysiological changes that underlie
specific clinical diseases. Here, we identify five transcription factors that reprogram
mouse and human fibroblasts into noxious stimulus-detecting (nociceptor) neurons that
recapitulate the expression of quintessential nociceptor-specific functional receptors and
channels found in adult mouse nociceptor neurons as well as native subtype diversity.
Moreover, the derived nociceptor neurons exhibit TrpV1 sensitization to the inflammatory
mediator prostaglandin E2 and the chemotherapeutic drug oxaliplatin, modeling the inherent
mechanisms underlying inflammatory pain hypersensitivity and painful chemotherapy-induced
neuropathy. Using fibroblasts from patients with familial dysautonomia (hereditary sensory
and autonomic neuropathy type III), we show that the technique can reveal novel aspects of
human disease phenotypes in vitro.
O desenvolvimento e implantação de sistemas de gestão da qualidade e o uso de programas e ferramentas da qualidade são algumas das opções mais utilizadas pelos gestores para aumentar a competitividade de suas empresas. Nesse contexto, o objetivo deste artigo é apresentar o resultado de uma pesquisa tipo survey em que se verificaram e analisaram as principais características do processo de certificação ISO 9001, seus benefícios, suas dificuldades e quais programas e ferramentas da qualidade são utilizados em 236 empresas do interior do Estado de São Paulo. A pesquisa revelou que a certificação ISO 9001 gera benefícios significativos às organizações, tais como: melhoria dos processos internos e nos seus produtos; aumento da satisfação dos clientes; diminuição do número de não conformidades e de devoluções; aumento da produtividade e do lucro; melhoria no gerenciamento dos recursos e valorização da imagem da empresa no mercado. Ela também ratificou a importância da utilização dos programas e ferramentas da qualidade como forma de as empresas se adequarem melhor aos requisitos da norma ISO 9001. As dificuldades de desenvolvimento e implantação desses sistemas não se confirmaram para a amostra pesquisada. Apenas a resistência à mudança, dentre todas apresentadas, mereceu destaque para os pesquisados.
We studied the morphology and the cortical representation of the median nerve (MN), 10 weeks after a transection immediately followed by treatment with tubulization using a polycaprolactone (PCL) conduit with or without bone marrow-derived mesenchymal stem cell (MSC) transplant. In order to characterize the cutaneous representation of MN inputs in primary somatosensory cortex (S1), electrophysiological cortical mapping of the somatosensory representation of the forepaw and adjacent body parts was performed after acute lesion of all brachial plexus nerves, except for the MN. This was performed in ten adult male Wistar rats randomly assigned in three groups: MN Intact (n = 4), PCL-Only (n = 3), and PCL+MSC (n = 3). Ten weeks before mapping procedures in animals from PCL-Only and PCL+MSC groups, animal were subjected to MN transection with removal of a 4-mm-long segment, immediately followed by suturing a PCL conduit to the nerve stumps with (PCL+MSC group) or without (PCL-Only group) injection of MSC into the conduit. After mapping the representation of the MN in S1, animals had a segment of the regenerated nerve processed for light and transmission electron microscopy. For histomorphometric analysis of the nerve segment, sample size was increased to five animals per experimental group. The PCL+MSC group presented a higher number of myelinated fibers and a larger cortical representation of MN inputs in S1 (3,383 ± 390 fibers; 2.3 mm2, respectively) than the PCL-Only group (2,226 ± 575 fibers; 1.6 mm2). In conclusion, MSC-based therapy associated with PCL conduits can improve MN regeneration. This treatment seems to rescue the nerve representation in S1, thus minimizing the stabilization of new representations of adjacent body parts in regions previously responsive to the MN.
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