Publications by authors named "Alexander Howell"

A micro-cantilever technique applied to individual leaf epidermis cells of intact Arabidopsis thaliana and Nicotiana tabacum synthesizing genetically encoded calcium indicators (R-GECO1 and GCaMP3) revealed that compressive forces induced local calcium peaks that preceded delayed, slowly moving calcium waves. Releasing the force evoked significantly faster calcium waves. Slow waves were also triggered by increased turgor and fast waves by turgor drops in pressure probe tests.

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Takotsubo cardiomyopathy (TTC) is a reversible form of myocardial injury characterized by transient systolic and diastolic dysfunction secondary to regional left ventricle (LV) wall motion abnormalities. We present a case of a rare variant of TTC, termed reverse TTC (rTTC), involving basal hypokinesis with apical hyperkinesis accounting for less than 5% of identified cases of TTC. Our patient is a 49-year-old Hispanic female who presented for evaluation of dyspnea.

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Forisomes are protein bodies known exclusively from sieve elements of legumes. Forisomes contribute to the regulation of phloem transport due to their unique Ca2+-controlled, reversible swelling. The assembly of forisomes from sieve element occlusion (SEO) protein monomers in developing sieve elements and the mechanism(s) of Ca2+-dependent forisome contractility are poorly understood because the amino acid sequences of SEO proteins lack conventional protein-protein interaction and Ca2+-binding motifs.

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Introduction: The prevalence of atopic dermatitis (AD) in geriatric populations of industrialized countries is currently estimated at 3-4% and continues to increase. AD is associated with significant morbidity, increased susceptibility to infection, and symptoms of pruritus and pain. Treatments may negatively affect elderly patients; thus, plans should be optimized for this population.

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The microinjection of fluorescent probes into live cells is an essential component in the toolbox of modern cell biology. Microinjection techniques include the penetration of the plasma membrane and, if present, the cell wall with micropipettes, and the application of pressure or electrical currents to drive the micropipette contents into the cell. These procedures interfere with cellular functions and therefore may induce artifacts.

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In plants, a complex mixture of solutes and macromolecules is transported by the phloem. Here, we examined how solutes and macromolecules are separated when they exit the phloem during the unloading process. We used a combination of approaches (non-invasive imaging, 3D-electron microscopy, and mathematical modelling) to show that phloem unloading of solutes in Arabidopsis roots occurs through plasmodesmata by a combination of mass flow and diffusion (convective phloem unloading).

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