Publications by authors named "Bear J"

Article Synopsis
  • X-ray CT often requires contrast agents to improve soft tissue diagnosis, but traditional agents involve high doses that can be risky for certain patients.
  • Dark-field X-ray imaging offers a more sensitive alternative by using scattered radiation to enhance image contrast, which hasn't yet been fully leveraged for contrast agent innovation.
  • This study shows that high-Z nanoparticles can create better dark-field contrast due to their higher electron density, improving detection sensitivity over traditional iodine-based agents while using the same X-ray dose.
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As part of a much larger study on non-covalent interactions in binary adducts, we have explored the solid-state structures of bromopentafluorobenzene (CFBr) using differential scanning calorimetry (DSC), variable-temperature powder X-ray diffraction (VT-PXRD), and single-crystal X-ray diffraction (SXD). DSC data initially indicated a single solid-state phase below the freezing point, but revealed additional weak transitions upon heating. The crystal structures of three solid-state phases have been solved.

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BACKGROUNDAn HIV-1 DNA vaccine composed of 7 highly conserved, structurally important elements (conserved elements, CE) of p24Gag was tested in a phase I randomized, double-blind clinical trial (HVTN 119, NCT03181789) in people without HIV. DNA vaccination of CE prime/CE+p55Gag boost was compared with p55Gag.METHODSTwo groups (n = 25) received 4 DNA vaccinations (CE/CE+p55Gag or p55Gag) by intramuscular injection/electroporation, including IL-12 DNA adjuvant.

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Magnetic field hyperthermia relies on the intra-tumoural delivery of magnetic nanoparticles by interstitial injection, followed by their heating on exposure to a remotely-applied alternating magnetic field (AMF). This offers a potential sole or adjuvant route to treating drug-resistant tumours for which no alternatives are currently available. However, two challenges in nanoparticle delivery currently hinder the effective clinical translation of this technology: obtaining enough magnetic material within the tumour to enable sufficient heating; and doing this accurately to limit or avoid damage to surrounding healthy tissue.

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The monomer-binding protein profilin 1 (PFN1) plays a crucial role in actin polymerization. However, mutations in PFN1 are also linked to hereditary amyotrophic lateral sclerosis, resulting in a broad range of cellular pathologies which cannot be explained by its primary function as a cytosolic actin assembly factor. This implies that there are important, undiscovered roles for PFN1 in cellular physiology.

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Introduction: Approximately 50% of melanomas harbor an activating mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. loss-of-function mutations occur in ~40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy.

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Article Synopsis
  • Profilin 1 (PFN1) plays a crucial role in both actin assembly and microtubule growth, but its primary mechanism of influencing microtubules—either directly by regulating tubulin or indirectly through actin polymerization—remains unclear.
  • By adjusting PFN1 levels, actin filament formation, and actomyosin function, researchers found that reducing these elements led to adaptive changes in the microtubule cytoskeleton, especially in neuronal cells.
  • Importantly, these microtubule alterations were reversible with the restoration of actomyosin, suggesting PFN1 mainly regulates microtubules through actin, and that disturbances in actin may result in significant functional changes in other
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Background: The brain is built of neurons supported by myelin, a fatty substance that improves cellular communication. Noninvasive magnetic resonance imaging (MRI) is now able to measure brain structure like myelin and requires histological validation.

New Method: Here we present work in small and large biomedical model mammals to standardize a silver impregnation method as a high-throughput histological myelin visualization procedure.

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Sulfur polymers produced through 'inverse vulcanization' exhibit various attributes, such as photocatalytic activity and a high capacity to adsorb heavy metals. Nevertheless, there is a lack of research investigating the use of sulfur polymers as materials for the removal of organic contaminants. In this work, porous sulfur polymers (PSPs) were synthesized from elemental sulfur and 1,3-diisopropenylbenzene, with porosity introduced via salt templating.

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The ability to dynamically assemble contractile networks is required throughout cell physiology, yet direct biophysical mechanisms regulating non-muscle myosin 2 filament assembly in living cells are lacking. Here, we use a suite of dynamic, quantitative imaging approaches to identify deterministic factors that drive myosin filament appearance and amplification. We find that actin dynamics regulate myosin assembly, but that the static actin architecture plays a less clear role.

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Cell therapy is a potential treatment for cystic fibrosis (CF). However, cell engraftment into the airway epithelium is challenging. Here, we model cell engraftment in vitro using the air-liquid interface (ALI) culture system by injuring well-differentiated CF ALI cultures and delivering non-CF cells at the time of peak injury.

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Protein-based biomaterial use is expanding within medicine, together with the demand to visualize their placement and behavior in vivo. However, current medical imaging techniques struggle to differentiate between protein-based implants and surrounding tissue. Here a fast, simple, and translational solution for tracking transplanted protein-based scaffolds is presented using X-ray CT-facilitating long-term, non-invasive, and high-resolution imaging.

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Article Synopsis
  • Cytokines and chemokines are important for our immune system, especially after getting vaccinated against COVID-19 with the BNT162b2 mRNA vaccine.
  • Researchers studied how these substances in the body respond after people received their third dose of the vaccine, comparing it to responses after the first and second doses.
  • They found that some immune responses lasted longer after the third dose and were linked to making more antibodies that help fight off the virus.
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Objective: The primary objective of the study was to assess the immunogenicity of an HIV-1 Gag conserved element DNA vaccine (p24CE DNA) in people with HIV (PWH) receiving suppressive antiretroviral therapy (ART).

Design: AIDS Clinical Trials Group A5369 was a phase I/IIa, randomized, double-blind, placebo-controlled study of PWH receiving ART with plasma HIV-1 RNA less than 50 copies/ml, current CD4 + T-cell counts greater than 500 cells/μl, and nadir CD4 + T-cell counts greater than 350 cells/μl.

Methods: The study enrolled 45 participants randomized 2 : 1 : 1 to receive p24CE DNA vaccine at weeks 0 and 4, followed by p24CE DNA admixed with full-length p55 Gag DNA vaccine at weeks 12 and 24 (arm A); full-length p55 Gag DNA vaccine at weeks 0, 4, 12, and 24 (arm B); or placebo at weeks 0, 4, 12, and 24 (arm C).

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Humor expression is a potent interpersonal and professional communication tool, conveying intelligence and competence. This review examines the role of gender in outcomes of humor expression, particularly in professional settings. Despite humor's association with masculinity and stereotypes that women are less funny than men, we highlight findings that suggest potentially nuanced benefits of humor for women, depending upon contextual moderators including humor type and status.

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Type 1 IFN expression is critical in the innate immune response, but aberrant expression is associated with autoimmunity and cancer. Here, we identify N-[4-(1H46 pyrazolo[3,4-b] pyrazin-6-yl)-phenyl]-sulfonamide (Sanofi-14h), a compound with preference for inhibition of the AGC family kinase SGK3, as an inhibitor of Ifnb1 gene expression in response to STING stimulation of macrophages. Sanofi-14h abrogated SGK activity and also impaired activation of the critical TBK1/IRF3 pathway downstream of STING activation, blocking interaction of STING with TBK1.

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Testicular neoplasms, or testicular cancer, are not typically seen in the emergency department (ED) since their presentation involves a painless hard mass that emerges slowly over time. Uncommon presentation of testicular neoplasm to the ED with acute onset of scrotal pain may present challenges as an incomplete physical examination without supplemental imaging and laboratory workup may overlook the diagnosis of testicular neoplasm. As a result, a delay in proper treatment may occur.

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Multi-grain crystallography, traditionally performed at synchrotron sources in association with high-pressure studies, has new relevance with respect to laboratory single-crystal X-ray diffraction, in which crystals can be grown rapidly in situ, and a preliminary dataset analysed and solved in a matter of minutes. Subsequently, a full-sphere of IUCr-quality data can then be collected in a few hours. To demonstrate the applicability of laboratory multi-grain crystallography with Cu Kα X-rays, co-crystals of hexafluorobenzene and pyrrole were grown rapidly by cooling a 1:1 liquid mixture in an X-ray capillary on the diffractometer.

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Article Synopsis
  • * Long-term depletion of F-actin or actomyosin contractility leads to increased levels of acetylated microtubules and intermediate filaments, especially in neuronal processes.
  • * Restoring F-actin and myosin activity can reverse changes in microtubules, but changes due to actin depletion can disrupt microtubule transport, potentially leading to neurodegenerative symptoms.
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To generate forces that drive migration of a eukaryotic cell, arrays of actin filaments (F-actin) are assembled at the cell's leading membrane edge. To maintain cell propulsion and respond to dynamic external cues, actin filaments must be disassembled to regenerate the actin monomers (G-actin), and transport of G-actin from sites of disassembly back to the leading edge completes the treadmilling cycle and limits the flux of F-actin assembly. Whether or not molecular diffusion is sufficient for G-actin transport has been a long-standing topic of debate, in part because the dynamic nature of cell motility and migration hinders the estimation of transport parameters.

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Article Synopsis
  • Profilin 1 (PFN1) is crucial for forming actin filaments and its absence leads to an increase in mitophagy, the process that removes damaged mitochondria.
  • Despite the heightened activity in removing defective mitochondria, PFN1 knockout cells still accumulate dysfunctional mitochondria, indicating a failure in quality control.
  • PFN1 not only influences mitochondria's shape and function from within but also its ALS mutants worsen mitochondrial problems, hinting at a new understanding of PFN1's role in both mitochondrial regulation and ALS pathology.
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Introduction: Glaucoma is a group of progressive optic neuropathies resulting in irreversible blindness. It is associated with an elevation of intraocular pressure (>21 mm Hg) and optic nerve damage. Reduction of the intraocular pressure (IOP) through the administration of ocular hypotensive eye drops is one of the most common therapeutic strategies.

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The ability to dynamically assemble contractile networks is required throughout cell physiology, yet the biophysical mechanisms regulating non-muscle myosin 2 filament assembly in living cells are lacking. Here we use a suite of dynamic, quantitative imaging approaches to identify deterministic factors that drive myosin filament appearance and amplification. We find that actin dynamics regulate myosin assembly, but that the actin architecture plays a minimal direct role.

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We employed a dose-escalation regimen in rhesus macaques to deliver glycosylated IL-7, a cytokine critical for development and maintenance of T lymphocytes. IL-7 increased proliferation and survival of T cells and triggered several chemokines and cytokines. Induction of CXCL13 in lymph nodes (LNs) led to a remarkable increase of B cells in the LNs, proliferation of germinal center follicular T helper cells and elevated IL-21 levels suggesting an increase in follicle activity.

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