Publications by authors named "J Steven Alexander"

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) benefits patients with cardiogenic shock (CS) but can increase left ventricular afterload and exacerbate pulmonary edema. Adding a percutaneous left ventricular assist device (LVAD) to VA-ECMO can optimize the hemodynamics. Because managing VA-ECMO and LVAD simultaneously is complex and labor-intensive, we developed a closed-loop automated control system for VA-ECMO and LVAD.

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Background: Shoulder pain-mostly related to rotator cuff tendinopathy-is the most common reason adults seek upper limb specialty care. Tendinopathy of the long head of the biceps may be part of rotator cuff tendinopathy, which most of us develop as we age. Evidence that these processes are related and that both are part of human shoulder senescence could contribute to a reconceptualization of shoulder tendinopathy as a single set of age-related changes, which are often well-accommodated, sometimes misinterpreted as an injury, and associated with notable nonspecific treatment effects, thus meriting caution regarding the potential for overtreatment.

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Image-based spatial transcriptomics platforms are powerful tools often used to identify cell populations and describe gene expression in intact tissue. Spatial experiments return large, high-dimension datasets and several open-source software packages are available to facilitate analysis and visualization. Spatial results are typically imperfect.

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Objective: Vagus nerve stimulation (VNS) paired with rehabilitation therapy improved motor status compared to rehabilitation alone in the phase III VNS-REHAB stroke trial, but treatment response was variable and not associated with any clinical measures acquired at baseline, such as age or side of paresis. We hypothesized that neuroimaging measures would be associated with treatment-related gains, examining performance of regional injury measures versus global brain health measures in parallel with clinical measures.

Methods: Baseline magnetic resonance imaging (MRI) scans in the VNS-REHAB trial were used to derive regional injury measures (extent of injury to corticospinal tract, the primary regional measure; plus extent of injury to precentral gyrus and postcentral gyrus; lesion volume; and lesion topography) and global brain health measures (degree of white matter hyperintensities, the primary global brain measure; plus volumes of cerebrospinal fluid, cortical gray matter, white matter, each thalamus, and total brain).

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