Publications by authors named "Daniel Parrott"

Asteroid discoveries are essential for planetary-defense efforts aiming to prevent impacts with Earth, including the more frequent megaton explosions from decameter impactors. While large asteroids (≥100 km) have remained in the main belt since their formation, small asteroids are commonly transported to the near-Earth object (NEO) population. However, due to the lack of direct observational constraints, their size-frequency distribution -which informs our understanding of the NEOs and the delivery of meteorite samples to Earth-varies significantly among models.

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Article Synopsis
  • Previous research indicated that the MRI probe GdL1 can differentiate between healthy and cancerous prostate tissues based on zinc levels.
  • Mice were given varying zinc diets for three weeks, and their prostate zinc secretion was analyzed using advanced imaging techniques.
  • Results showed that healthy mice effectively regulated zinc levels, while cancerous mice struggled, suggesting that zinc supplements before imaging could improve prostate cancer detection accuracy.
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Purpose: Recently, we reported that exposure of prostate cells in vitro or the in vivo prostate to high glucose results in release of Zn ions, a process now referred to as glucose-stimulated zinc secretion (GSZS). To our knowledge, the metabolic event(s) that trigger GSZS remain largely unknown. Here, we explore several signaling pathways both in vitro using a prostate epithelial cell line and in vivo from the rat prostate.

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An imaging method for detecting β-cell function in real-time in the rodent pancreas could provide new insights into the biological mechanisms involving loss of β-cell function during development of type 2 diabetes and for testing of new drugs designed to modulate insulin secretion. In this study, we used a zinc-responsive MRI contrast agent and an optimized 2D MRI method to show that glucose stimulated insulin and zinc secretion can be detected as functionally active "hot spots" in the tail of the rat pancreas. A comparison of functional images with histological markers show that insulin and zinc secretion does not occur uniformly among all pancreatic islets but rather that some islets respond rapidly to an increase in glucose while others remain silent.

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Histologic phenotypic variation of benign prostatic hyperplasia (BPH) has been hypothesized to underlie response to medical therapy. We evaluate preoperative MRI of robot-assisted simple prostatectomy (RASP) specimens and determine imaging features associated with histologic phenotype. All patients undergoing RASP from November 2015 to November 2019 with a multiparametric MRI ≤1 year before RASP were included.

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Objectives: In the United States, prostate cancer (PCa) is the most common cancer in men. Multi-parametric magnetic resonance imaging (MRI) is increasingly being relied upon for the diagnosis and characterization of PCa, but differentiating malignancy from benign prostatic hyperplasia (BPH) in the transition zone using MRI can be challenging. The characteristically high levels of zinc in human prostate tissue and a close relationship between malignant proliferation and zinc homeostatic dysregulation create opportunities to visualize PCa with novel contrast media.

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Purpose: The aims of this study were to assess the fidelity of electronic health record documentation prompting premedication to iodinated contrast media and to determine the appropriateness of administered premedication on the basis of that documentation.

Methods: In this retrospective quality assurance cohort study, medication adverse events recorded in electronic health records between January 1, 2018, and August 31, 2019, to "iodine," "iodine-containing products," and "iodinated contrast media" were identified (N = 4,309); entries missing documentation (n = 1,651) and breakthrough reactions (n = 22) were excluded. Reaction description, severity, and free-text comments were used to categorize each entry as concordant (documentation matches recorded severity per the ACR Manual on Contrast Media version 10.

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Purpose: We have previously demonstrated by MRI that high glucose stimulates efflux of zinc ions from the prostate. To our knowledge, this phenomena had not been reported previously and the mechanism remains unknown. Here, we report some initial observations that provide new insights into zinc processing during glucose-stimulated zinc secretion (GSZS) in the immortalized human prostate epithelial cell line, PNT1A.

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Paramagnetic metal ion complexes, mostly based on gadolinium (Gd), have been used for over 30 years as magnetic resonance imaging (MRI) contrast agents. Gd-based contrast agents have a strong influence on T relaxation times and are consequently the most commonly used agents in both the clinical and research environments. Zinc is an essential element involved with over 3000 different cellular proteins, and disturbances in tissue levels of zinc have been linked to a wide range of pathologies, including Alzheimer's disease, prostate cancer, and diabetes mellitus.

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