Publications by authors named "Andrew Sayce"

Sepsis is a life-threatening condition involving a dysregulated immune response to infectious agents that cause injury to host tissues and organs. Current treatments are limited to early administration of antibiotics and supportive care. While appealing, the strategy of targeted inhibition of individual molecules in the inflammatory cascade has not proved beneficial.

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Background: Traumatic injury results in both physical and physiologic insult. Successful care of the trauma patient depends upon timely correction of both physical and biochemical injury. Trauma-induced coagulopathy is a derangement of hemostasis and thrombosis that develops rapidly and can be fatal if not corrected.

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The antiviral mechanism of action of iminosugars against many enveloped viruses is hypothesized to be a consequence of misfolding of viral N-linked glycoproteins through inhibition of host endoplasmic reticulum α-glucosidase enzymes. Iminosugar treatment of dengue virus (DENV) infection results in reduced secretion of virions and hence lower viral titres in vitro and in vivo. We investigated whether iminosugars might also affect host receptors important in DENV attachment and uptake and immune responses to DENV.

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Article Synopsis
  • * ToP-DNJ, a new antiviral iminosugar-tocopherol conjugate, is designed to target the liver and immune cells for antiviral treatment.
  • * The drug effectively inhibits ER α-glucosidase II and shows significant action only in immune cells, highlighting the benefits of combining native metabolites for improved selectivity in drug design.
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Influenza virus causes three to five million severe respiratory infections per year in seasonal epidemics, and sporadic pandemics, three of which occurred in the twentieth century and are a continuing global threat. Currently licensed antivirals exclusively target the viral neuraminidase or M2 ion channel, and emerging drug resistance necessitates the development of novel therapeutics. It is believed that a host-targeted strategy may combat the development of antiviral drug resistance.

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  • Iminosugars, specifically NB-DNJ and MON-DNJ, were tested for safety and antiviral effects against Ebola virus in guinea pigs, showing no adverse effects at administered dosages.
  • NB-DNJ indicated some potential efficacy, with 1 out of 4 treated infected guinea pigs surviving and others showing improved health, while MON-DNJ provided no protective benefits.
  • However, follow-up studies did not confirm the antiviral effects of iminosugars, suggesting further research is needed to develop more effective versions.
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  • Research indicates that iminosugars, previously thought to primarily inhibit α-glucosidases in the endoplasmic reticulum (ER), may have multiple antiviral mechanisms impacting various viral infections, including dengue virus (DENV).
  • Celgosivir, a type of bicyclic iminosugar, has shown promise as an antiviral agent in treating DENV in clinical models and has been confirmed to inhibit DENV secretion in human macrophages.
  • The study establishes that the antiviral effectiveness of iminosugars against DENV is more closely related to ER α-glucosidase inhibition rather than the processing of glycolipids, highlighting the need for further exploration of iminosugar mechanisms.
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The antiviral activity of UV-4 was previously demonstrated against dengue virus serotype 2 (DENV2) in multiple mouse models. Herein, step-wise minimal effective dose and therapeutic window of efficacy studies of UV-4B (UV-4 hydrochloride salt) were conducted in an antibody-dependent enhancement (ADE) mouse model of severe DENV2 infection in AG129 mice lacking types I and II interferon receptors. Significant survival benefit was demonstrated with 10-20 mg/kg of UV-4B administered thrice daily (TID) for seven days with initiation of treatment up to 48 h after infection.

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A key challenge faced by promising antiviral drugs, such as iminosugars, is in vivo delivery to achieve effective levels of drug without toxicity. Four iminosugars, all deoxynojirimycin (DNJ) derivatives-N-butyl DNJ (NB-DNJ), N-nonyl DNJ, N-(9-methoxynonyl) DNJ, and N-(6'-[4″-azido-2″-nitrophenylamino]hexyl)-1-DNJ (NAP-DNJ)-potently inhibited both the percentage of cells infected with dengue virus and release of infectious virus from primary human monocyte-derived macrophages, demonstrating their efficacy in primary cells. In a lethal antibody-dependent enhancement mouse model of dengue pathogenesis, free NB-DNJ significantly enhanced survival and lowered viral load in organs and serum.

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The majority of the glycolytic enzymes in the African trypanosome are compartmentalised within peroxisome-like organelles, the glycosomes. Polypeptides harbouring peroxisomal targeting sequences (PTS type 1 or 2) are targeted to these organelles. This targeting is essential to parasite viability, as compartmentalisation of glycolytic enzymes prevents unregulated ATP-dependent phosphorylation of intermediate metabolites.

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Background: Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls.

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The re-emergence of dengue virus as a significant human pathogen has lead to an increasing need for effective antivirals. Development of therapeutic agents with the ability to attenuate both the duration and severity of disease in patients after infection is particularly desirable in dengue endemic resource-poor settings. The reliance of dengue virus on endogenous processes during the late stages of infection prompts the development of molecules to interfere with and exploit these dependencies as potential antiviral therapies.

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