Publications by authors named "Alastair Brown"

Purpose: Furosemide is the most commonly used diuretic in intensive care units (ICU). We aimed to evaluate the physiological effects of adjunctive acetazolamide with furosemide on diuresis and the prevention of potential furosemide-induced metabolic alkalosis.

Materials And Methods: We performed a two-center, pilot, open-label, randomized trial.

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The development of nonopioid analgesics for the treatment of abdominal pain is a pressing clinical problem. To address this, we examined the expression of Gi/o-coupled receptors, which typically inhibit nociceptor activation, in colonic sensory neurons. This led to the identification of the orphan receptor GPR35 as a visceral analgesic drug target because of its marked coexpression with transient receptor potential ankyrin 1 (TRPA1), a mediator of noxious mechanotransduction in the bowel.

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Aneurysmal subarachnoid hemorrhage (aSAH) is characterized by high mortality and morbidity. This scoping review assesses the current evidence regarding the use of sedatives and analgesics in the acute intensive care unit management of aSAH. We conducted a systematic search of Ovid MEDLINE, Ovid Embase, Ovid EmCare, APA PsycInfo, CINAHL, and the Cochrane Database of Systematic Reviews from inception to June 2023.

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Objectives: To compare in-hospital mortality and intensive care unit (ICU) length of stay for people admitted to Australian and New Zealand ICUs during 2022-23 with coronavirus disease 2019 (COVID-19) pneumonitis, incidental or exacerbating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, or without SAR-CoV-2 infections.

Study Design: Retrospective cohort study; analysis of Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database data.

Setting, Participants: Adults (16 years or older) admitted to participating ICUs in Australia or New Zealand, 1 January 2022 - 30 June 2023.

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Introduction: Venovenous extracorporeal membrane oxygenation (VV ECMO) is used for refractory hypoxemia, although despite this, in high cardiac output states, hypoxaemia may persist. The administration of beta-blockers has been suggested as an approach in this scenario, however the physiological consequences of this intervention are not clear.

Methods: We performed an in-silico study using a previously described mathematical model to evaluate the effect of beta-blockade on mixed venous and arterial saturations (, ), in three different clinical scenarios and considered the potential effects of beta-blockers on, cardiac output, oxygen consumption and recirculation.

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Background: The use of composite outcome measures (COM) in clinical trials is increasing. Whilst their use is associated with benefits, several limitations have been highlighted and there is limited literature exploring their use within critical care. The primary aim of this study was to evaluate the use of COM in high-impact critical care trials, and compare study parameters (including sample size, statistical significance, and consistency of effect estimates) in trials using composite versus non-composite outcomes.

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The Australian Traumatic Brain Injury Initiative (AUS-TBI) is developing a data resource to enable improved outcome prediction for people with moderate-severe TBI (msTBI) across Australia. Fundamental to this resource is the collaboratively designed data dictionary. This systematic review and consultation aimed to identify acute interventions with potential to modify clinical outcomes for people after msTBI, for inclusion in a data dictionary.

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Objective: Somatostatin receptor ligands have come to play a pivotal role in the treatment of both ACTH- and GH-secreting pituitary adenomas. Clinical efficacy averages 30-50%, thus a considerable number of patients with Cushing's disease or acromegaly remain unresponsive to this therapeutic approach. HTL0030310 is a new somatostatin receptor ligand selective for subtype 5 over subtype 2, thus with a different receptor profile compared to clinical somatostatin receptor ligands.

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Article Synopsis
  • - This review focuses on three main objectives: understanding factors affecting oxygen levels in patients on ECMO, examining how hyperoxia impacts patient outcomes, and offering practical guidance on adjusting oxygen levels during treatment.
  • - Research included observational and interventional studies as well as guidelines from the Extracorporeal Life Support Organization to gather evidence about hyperoxia and clinical results.
  • - Findings indicate that both the ECMO machine and a patient’s natural heart and lung function influence systemic oxygenation, with high risks of hyperoxia emerging during treatment, which can increase the chances of in-hospital mortality.
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Persistent critical illness (PerCI) is defined as an intensive care unit (ICU) admission lasting ≥ 10 days. The in-hospital complications associated with its development are poorly understood. To test whether PerCI is associated with a greater prevalence, rate and specific types of in-hospital complications.

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Background: Medical emergency team (METs), activated by vital sign-based calling criteria respond to deteriorating patients in the hospital setting. Calling criteria may be altered where clinicians feel this is appropriate. Altered calling criteria (ACC) has not previously been evaluated in the emergency department (ED) setting.

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Patients with respiratory failure may remain hypoxemic despite treatment with venovenous extracorporeal membrane oxygenation (VV-ECMO). Therapeutic hypothermia is a potential treatment for such hypoxia as it reduces cardiac output ( ) and oxygen consumption. We modified a previously published mathematical model of gas exchange to investigate the effects of hypothermia during VV-ECMO.

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Introduction: The apelin receptor binds two distinct endogenous peptides, apelin and ELA, which act in an autocrine/paracrine manner to regulate the human cardiovascular system. As a class A GPCR, targeting the apelin receptor is an attractive therapeutic strategy. With improvements in imaging techniques, and the stability and brightness of dyes, fluorescent ligands are becoming increasingly useful in studying protein targets.

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Article Synopsis
  • Research indicates that muscarinic receptors, specifically M1 and M4, play a significant role in the molecular issues related to schizophrenia.
  • Clinical trials show that activating these receptors can help reduce various symptoms of schizophrenia, including positive, negative, and cognitive symptoms.
  • Advances in neuroimaging have allowed for better visualization of these receptors in the brain, highlighting a potential subgroup of schizophrenia patients who may benefit from targeted drug therapies aimed at restoring muscarinic M1 receptor function.
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Introduction: This study examined the safety and pharmacodynamic effects of selective muscarinic M receptor orthosteric agonist HTL0018318 in 60 patients with mild-to-moderate Alzheimer's disease (AD) on background donepezil 10 mg/day.

Methods: A randomized, double-blind, placebo-controlled 4-week safety study of HTL0018318 with up-titration and maintenance phases, observing exploratory effects on electrophysiological biomarkers and cognition.

Results: Treatment-emergent adverse events (TEAEs) were mild and less frequently reported during maintenance versus titration.

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Current therapies for Alzheimer's disease seek to correct for defective cholinergic transmission by preventing the breakdown of acetylcholine through inhibition of acetylcholinesterase, these however have limited clinical efficacy. An alternative approach is to directly activate cholinergic receptors responsible for learning and memory. The M1-muscarinic acetylcholine (M1) receptor is the target of choice but has been hampered by adverse effects.

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Purpose: To assess the feasibility and physiological efficacy of adjunctive midodrine in patients with vasopressor-dependent hypotension.

Materials And Methods: This was a pilot, open label, randomised controlled trial. Patients were enrolled from two tertiary intensive care units on low dose intravenous vasopressor therapy for more than 24 h.

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Acetylcholine release in the hippocampus plays a central role in the formation of new memory representations. An influential but largely untested theory proposes that memory formation requires acetylcholine to enhance responses in CA1 to new sensory information from entorhinal cortex whilst depressing inputs from previously encoded representations in CA3. Here, we show that excitatory inputs from entorhinal cortex and CA3 are depressed equally by synaptic release of acetylcholine in CA1.

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Background: Elabela/Toddler (ELA) is a novel endogenous ligand of the apelin receptor, whose signalling has emerged as a therapeutic target, for example, in cardiovascular disease and cancer. Shorter forms of ELA-32 have been predicted, including ELA-21 and ELA-11, but metabolism and stability of ELA-32 in humans is poorly understood. We, therefore, developed an LC-MS/MS assay to identify ELA-32 metabolites in human plasma and tissues.

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Article Synopsis
  • HTL0009936 is being tested as a treatment for cognitive dysfunction in Alzheimer's disease, focusing on its safety, tolerability, and pharmacokinetics in elderly patients with below average cognitive functioning.
  • The study involved two parts: one evaluated HTL0009936's effects on healthy elderly subjects, while the second part used a randomized approach to assess its effects in subjects with cognitive impairments, measuring cognitive and electrical brain responses.
  • Results indicate that HTL0009936 is generally safe and well-tolerated, showing some effects on brain activity (P300), but no conclusive evidence of significant cognitive improvement due to design changes that limited optimal drug exposure during testing.
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