97 research outputs found

    Amyloid-β Inhibits No-cGMP Signaling in a CD36- and CD47-Dependent Manner

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    Amyloid-β interacts with two cell surface receptors, CD36 and CD47, through which the matricellular protein thrombospondin-1 inhibits soluble guanylate cyclase activation. Here we examine whether amyloid-β shares this inhibitory activity. Amyloid-β inhibited both drug and nitric oxide-mediated activation of soluble guanylate cyclase in several cell types. Known cGMP-dependent functional responses to nitric oxide in platelets and vascular smooth muscle cells were correspondingly inhibited by amyloid-β. Functional interaction of amyloid-β with the scavenger receptor CD36 was indicated by inhibition of free fatty acid uptake via this receptor. Both soluble oligomer and fibrillar forms of amyloid-β were active. In contrast, amyloid-β did not compete with the known ligand SIRPα for binding to CD47. However, both receptors were necessary for amyloid-β to inhibit cGMP accumulation. These data suggest that amyloid-β interaction with CD36 induces a CD47-dependent signal that inhibits soluble guanylate cyclase activation. Combined with the pleiotropic effects of inhibiting free fatty acid transport via CD36, these data provides a molecular mechanism through which amyloid-β can contribute to the nitric oxide signaling deficiencies associated with Alzheimer's disease

    Grounded Theory: A Qualitative Research Methodology for Physical Therapy

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    The interest in grounded theory methodology for physical therapy research has grown in recent years. Grounded theory is a qualitative research methodology, initially developed by sociologists Barney Glaser and Anselm L. Strauss. Significant variations in the approach were later introduced by Strauss and Corbin. The intent of grounded theory methodology is to generate a theory relating to a particular situation. Other distinguishing features of this method include the use of open-ended questioning, the synthesis of data collection with analysis, the use of theoretical sampling, and the systematic procedures for data collection, analysis, and theory development. The purposes of this article are to introduce the tenets of the grounded theory methodology, to present examples of how the methodology can be applied to physical therapy research, and to suggest criteria for evaluating grounded theory studies

    Post-Polio Syndrome Revisited

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    Post-polio syndrome (PPS) is characterized by recrudescence or worsening of motor neuron disease symptoms decades after recovery from acute paralytic poliovirus infection, i.e., poliomyelitis. PPS afflicts between 25% and 40% of poliomyelitis survivors and mimics motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS), due to its selective impairment, degeneration, or death of motor neurons in the brainstem and spinal cord. Herein, we report a case of PPS in a 68-year-old man with a remote history of bulbar and cervical cord involvement by poliomyelitis, review the relevant literature, and contrast the salient histopathologic features that distinguish our case of PPS from ALS

    Letters

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