Publications by authors named "Michael Dudley"

Objectives: Health systems are increasingly accountable for patients and require accurate electronic health record (EHR) vital status. We recently demonstrated that 19% of seriously ill primary care patients in one system were not marked dead in the EHR and 80% of these decedents had an encounter or appointment outstanding after death. Herein we describe the mechanism of identifying decedents whose death is not captured at the level of the EHR, characterize these decedents, and describe medications refilled after death.

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This was a phase I, randomized, double-blind, placebo-controlled, ascending single- and multiple-dose study of oral ceftibuten to describe the pharmacokinetics (PK) of ceftibuten (administered form) and ceftibuten (metabolite), and to describe safety and tolerability at higher than licensed doses. Subjects received single 400, 600, or 800 mg doses of ceftibuten on Days 1 and 4, followed by 7 days of twice-daily dosing from Days 4 to 10. Non-compartmental methods were used to describe parent drug and metabolite PK in plasma and urine.

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There are few issues that have been as vexing for the Australian healthcare community as the Australian governments policy of mandatory, indefinite, immigration detention. While many concepts have been used to begin to describe the many dilemmas faced by healthcare professionals and their resolution, they are limited, perhaps most fundamentally by the fact that immigration detention is antithetical to health and wellbeing. Furthermore, and while most advice recognises that the abolition of detention is the only option in overcoming these issues, it provides little guidance on how action within detention could contribute to this.

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Recently, several β-lactam (BL)/β-lactamase inhibitor (BLI) combinations have entered clinical testing or have been marketed for use, but limited direct comparative studies of their activity exist. Xeruborbactam (XER, also known as QPX7728), which is undergoing clinical development, is a cyclic boronate BLI with potent inhibitory activity against serine (serine β-lactamase) and metallo-β-lactamases (MBLs). The objectives of this study were (i) to compare the potency and spectrum of β-lactamase inhibition by various BLIs in biochemical assays using purified β-lactamases and in microbiological assays using the panel of laboratory strains expressing diverse serine and metallo-β-lactamases and (ii) to compare the potency of XER in combination with multiple β-lactam antibiotics to that of other BL/BLI combinations in head-to-head testing against recent isolates of carbapenem-resistant (CRE).

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The program is a popular and easy-to-use crystallography tool for indexing and simulating X-ray Laue patterns, but its previous versions lack search functions for recognizing Laue patterns taken from crystals with unknown orientations. To overcome this obstacle, a major upgrade of the program, called , is presented with three robust search schemes implemented: (i) crystal rotation along a single diffraction vector, (ii) a look-up method to search for reflection pairs matching the interplanar angle of two selected diffraction spots, and (iii) a more efficient look-up scheme to search for reflection triplets matching three interplanar angles. Extensive tests show that all these schemes, together with the convenient graphical user interfaces and highly optimized computing algorithms, are reliable and powerful for recognizing and fitting Laue patterns of any crystal taken under any diffraction geometry.

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Taniborbactam and xeruborbactam are dual serine-/metallo-beta-lactamase inhibitors (BLIs) based on a cyclic boronic acid pharmacophore that undergo clinical development. Recent report demonstrated that New Delhi metallo-beta-lactamase (NDM)-9 (differs from NDM-1 by a single amino acid substitution, E152K, evolved to overcome Zn (II) deprivation) is resistant to inhibition by taniborbactam constituting pre-existing taniborbactam resistance mechanism. Using microbiological and biochemical experiments, we show that xeruborbactam is capable of inhibiting NDM-9 and propose the structural basis for differences between two BLIs.

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Most cells can eliminate unstable or misfolded proteins through quality control mechanisms. In the inherited red blood cell disorder β-thalassemia, mutations in the β-globin gene (HBB) lead to a reduction in the corresponding protein and the accumulation of cytotoxic free α-globin, which causes maturation arrest and apoptosis of erythroid precursors and reductions in the lifespan of circulating red blood cells. We showed previously that excess α-globin is eliminated by Unc-51-like autophagy activating kinase 1 (ULK1)-dependent autophagy and that stimulating this pathway by systemic mammalian target of rapamycin complex 1 (mTORC1) inhibition alleviates β-thalassemia pathologies.

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The emergence of multidrug-resistant (MDR) Gram-negative pathogens is an urgent global medical challenge. The old polymyxin lipopeptide antibiotics (polymyxin B and colistin) are often the only therapeutic option due to resistance to all other classes of antibiotics and the lean antibiotic drug development pipeline. However, polymyxin B and colistin suffer from major issues in safety (dose-limiting nephrotoxicity, acute toxicity), pharmacokinetics (poor exposure in the lungs) and efficacy (negligible activity against pulmonary infections) that have severely limited their clinical utility.

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QPX7728 is a cyclic boronate ultrabroad-spectrum beta-lactamase inhibitor, with potent activity against both serine beta-lactamases and metallo-beta-lactamases. QPX7728 can be delivered systemically by the intravenous (i.v.

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In recognition of the need for effective oral therapies to treat Gram-negative bacterial infections, efforts were directed toward identifying an oral prodrug of β-lactamase inhibitor clinical candidate QPX7728. Seventeen prodrugs were synthesized; key properties investigated were rates of cleavage to the active form in vitro, pharmacokinetics across species, and crystallinity. Compound (QPX7831 Sodium) emerged with optimal properties across all key attributes.

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QPX7728 is a novel β-lactamase inhibitor (BLI) that belongs to a class of cyclic boronates. The first member of this class, vaborbactam, is a BLI in the recently approved Vabomere (meropenem-vaborbactam). In this paper we provide the overview of the biochemical, structural and microbiological studies that were recently conducted with QPX7728.

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As rooftop solar photovoltaic (PV) adoption in Australia is exponentially growing in the past decade, there is a need to promote effective product stewardship for PV panels reaching their end-of-life (EoL). This paper presents the development of a System Dynamics (SD) model for managing EoL rooftop PV panels based on the circular economy concept. Four stages of the SD modelling process include problem scoping and variable identification, model conceptualisation, SD model development, and scenario analysis.

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QPX7728 is an ultrabroad-spectrum beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases. QPX7728 enhances the potency of multiple beta-lactams in beta-lactamase-producing and spp. In this study, we evaluated the activity of QPX7728 (QPX; 8 μg/ml) combined with multiple beta-lactams against clinical isolates of with various beta-lactam resistance mechanisms.

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The pharmacokinetics and safety of biapenem were studied in 36 healthy adult subjects in a randomized, placebo-controlled, double blind, sequential single and multiple-ascending dose study using doses from 250 to 1250 mg administered three times a day using 3-hour infusions. Maximum concentrations for biapenem were achieved at the end of the 3-hour infusion. Biapenem exposure (AUC) increased in a slightly greater than dose-proportional manner following single and multiple doses with no evidence of accumulation with multiple doses.

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QPX7728 is a recently discovered ultra-broad-spectrum beta-lactamase inhibitor (BLI) with potent inhibition of key serine and metallo-beta-lactamases. QPX7728 enhances the potency of many beta-lactams, including carbapenems, in beta-lactamase-producing Gram-negative bacteria, including spp. The potency of meropenem alone and in combination with QPX7728 (1 to 16 μg/ml) was tested against 275 clinical isolates of (carbapenem-resistant [CRAB]) collected worldwide that were highly resistant to carbapenems (MIC and MIC for meropenem, 64 and >64 μg/ml).

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QPX7728 is an investigational ultrabroad-spectrum-beta-lactamase inhibitor (BLI) with potent inhibition of key serine and metallo-beta-lactamases. QPX7728 enhances the potency of many beta-lactams, including carbapenems, in isogenic strains of Gram-negative bacteria producing various beta-lactamases. The potency of meropenem alone and in combination with QPX7728 (tested at fixed concentrations of 1 to 16 μg/ml) was tested against 598 clinical isolates of carbapenem-resistant (CRE).

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QPX7728 is an ultrabroad-spectrum boronic acid beta-lactamase inhibitor that demonstrates inhibition of key serine and metallo-beta-lactamases at a nanomolar concentration range in biochemical assays with purified enzymes. The broad-spectrum inhibitory activity of QPX7728 observed in biochemical experiments translates into enhancement of the potency of many beta-lactams against strains of target pathogens producing beta-lactamases. The impacts of bacterial efflux and permeability on inhibitory potency were determined using isogenic panels of KPC-3-producing isogenic strains of and and OXA-23-producing strains of with various combinations of efflux and porin mutations.

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QPX7728 is an ultrabroad-spectrum boronic acid beta-lactamase inhibitor, with potent inhibition of key serine and metallo-beta-lactamases being observed in biochemical assays. Microbiological studies using characterized strains were used to provide a comprehensive characterization of the spectrum of beta-lactamase inhibition by QPX7728. The MICs of multiple antibiotics administered intravenously only (ceftazidime, piperacillin, cefepime, ceftolozane, and meropenem) and orally bioavailable antibiotics (ceftibuten, cefpodoxime, tebipenem) alone and in combination with QPX7728 (4 μg/ml), as well as comparator agents, were determined against panels of laboratory strains of and expressing over 55 diverse serine and metallo-beta-lactamases.

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Despite major advances in the β-lactamase inhibitor field, certain enzymes remain refractory to inhibition by agents recently introduced. Most important among these are the class B (metallo) enzyme NDM-1 of Enterobacteriaceae and the class D (OXA) enzymes of . Continuing the boronic acid program that led to vaborbactam, efforts were directed toward expanding the spectrum to allow treatment of a wider range of organisms.

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