Publications by authors named "Michael Mc Donald"

Objective: To review processes of resource allocation and the ethical considerations relevant to the fair allocation of a limited number of cochlear implants to increasing numbers of potential recipients.

Design: Review of relevant considerations.

Setting: Tertiary referral hospital.

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Recent studies have revealed that disruption of vitamin A signaling observed in Alzheimer's disease (AD) leads to beta-amyloid (Abeta) accumulation and memory deficits in rodents. The aim of the present study was to evaluate the therapeutic effect of all-trans retinoic acid (ATRA), an active metabolite of vitamin A, on the neuropathology and deficits of spatial learning and memory in amyloid precursor protein (APP) and presenilin 1 (PS1) double-transgenic mice, a well established AD mouse model. Here we report a robust decrease in brain Abeta deposition and tau phosphorylation in the blinded study of APP/PS1 transgenic mice treated intraperitoneally for 8 weeks with ATRA (20 mg/kg, three times weekly, initiated when the mice were 5 months old).

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Mechanical circulatory support has evolved markedly over recent years. ECMO (extra corporeal membrane oxygenation) is instituted for the management of life threatening pulmonary or cardiac failure (or both), when no other form of treatment has been or is likely to be successful. Most commonly, it is instituted in an emergency or urgent situation after failure of other treatment modalities.

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Background: The mining industry has one of the highest occupational rates of serious injury and fatality. Mine staff involved with rescue operations are often required to respond to physically challenging situations. This paper describes the physical attributes of mining rescue personnel.

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Closing the health inequity gap can be seen as an issue of justice, however what concretely best serves the interest of justice is in dispute. It is argued that standard policy-making mechanisms are inadequate to address this issue, and therefore more and better public dialogue is required. Drawing on deliberative democratic theory and practice, three public organizing considerations are offered: organizing within the state sphere, organizing within the public sphere, and using cross strategies.

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Oxidative stress is implicated in the cognitive deterioration associated with normal aging as well as neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. We investigated the effect of ascorbic acid (vitamin C) on oxidative stress, cognition, and motor abilities in mice null for gulono-gamma-lactone oxidase (Gulo). Gulo-/- mice are unable to synthesize ascorbic acid and depend on dietary ascorbic acid for survival.

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Gangliosides are expressed in the outer leaflet of the plasma membrane of the cells of all vertebrates and are particularly abundant in the nervous system. Ganglioside metabolism is closely associated with the pathology of Alzheimer's disease (AD). AD, the most common form of dementia, is a progressive degenerative disease of the brain characterized clinically by progressive loss of memory and cognitive function and eventually death.

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Aims: Patients in ASSENT-4 PCI undergoing tenecteplase-facilitated percutaneous coronary intervention (PCI) had more adverse events than those undergoing primary PCI. We analysed this to gain further insights.

Methods And Results: A total of 549 patients with facilitated PCI and 541 undergoing primary PCI were characterized according to the extent of ST resolution.

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Gangliosides have been shown to be necessary for beta-amyloid (Abeta) binding and aggregation. GD3 synthase (GD3S) is responsible for biosynthesis of the b- and c-series gangliosides, including two of the four major brain gangliosides. We examined Abeta-ganglioside interactions in neural tissue from mice lacking the gene coding for GD3S (St8sia1), and in a double-transgenic (APP/PSEN1) mouse model of Alzheimer's disease cross-bred with GD3S-/- mice.

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This article is a consensus statement by an international interdisciplinary group of academic experts and Canadian policy-makers on emerging ethical, legal and social issues in human embryonic stem cells (hESC) research in Canada. The process of researching consensus included consultations with key stakeholders in hESC research (regulations, stem cell researchers, and research ethics experts), preparation and distribution of background papers, and an international workshop held in Montreal in February 2007 to discuss the papers and debate recommendations. The recommendations provided in the consensus statement focus on issues of immediate relevance to Canadian policy-makers, including informed consent to hESC research, the use of fresh embryos in research, management of conflicts of interest, and the relevance of public opinion research to policy-making.

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The global war on terrorism has led to increased concern about the ability of the U.S. healthcare system to respond to casualties from a chemical, biological, or radiological agent attack.

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Many organisms use circadian clocks to keep temporal order and anticipate daily environmental changes. In Drosophila, the master clock gene Clock promotes the transcription of several key target genes. Two of these gene products, PER and TIM, repress CLK-CYC-mediated transcription.

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Background: Risk stratifying the diverse group of patients who present to hospital with chest discomfort remains challenging. Current clinical risk models, typically derived from selected populations, are limited by their relative complexity and the absence of a well-defined role of troponin.

Objective: To derive a simple clinical risk score from a large, unselected population of patients with chest discomfort and to delineate the prognostic value of an initial troponin measurement.

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The determination of the crystal orientation of regenerated cellulose fibers produced under different drawing regimes is presented. Orientation is determined by using wide-angle X-ray diffraction from a synchrotron source and by measuring the azimuthal width of equatorial reflections. The orientation parameter theta is then determined to compare fiber samples.

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The clinical diagnosis of cervical neoplasia by spectroscopic methods is potentially a reliable, fast and cost-effective alternative to the conventional smear test. However, it is currently limited by significant inter-patient variation in the spectroscopic properties of the cervix. Characterisation of suitable in vitro models of the spectroscopic changes that take place during neoplastic progression may prove to be a significant step towards the successful development of reliable in vivo systems.

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Ethical dilemmas in veterinary medicine.

Vet Clin North Am Small Anim Pract

January 2007

Veterinarians frequently encounter situations that are morally charged and potentially difficult to manage. Situation involving euthanasia, end-of-life care, economics, and inadequate provision of care create practical and moral dilemmas. Ethical tension may be attributable to differences in beliefs regarding the moral value of animals, client and veterinary responsibilities, and deciding what is best for an animal.

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The Barnes maze is a spatial memory task that requires subjects to learn the position of a hole that can be used to escape the brightly lit, open surface of the maze. Two experiments assessed the relative importance of spatial (extra-maze) versus proximal visible cues in solving the maze. In Experiment 1, four groups of mice were trained either with or without a discrete visible cue marking the location of the escape hole, which was either in a fixed or variable location across trials.

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Cystic adventitial disease of veins is a rare condition. We report the case of a 28-year-old man who presented with a swollen leg secondary to obstruction of the common femoral vein as a result of this disease. He underwent excision of the cyst and made a full recovery.

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Consumption of a diet that significantly elevates homocysteine (homocysteinemia) induces cell death in the CA3 hippocampal subfield in amyloid precursor protein (APP) over-expressing transgenic mice but not in wild-type controls. We assessed behavioral and other neuropathological effects of a homocysteinemia-inducing diet in aged APP-overexpressing mice. Starting at 16-18 months of age, mice were fed either a treatment diet lacking folate, choline, and methionine, and supplemented with homocysteine, or a control diet containing normal amounts of folate, choline and methionine but no homocysteine.

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Rationale And Objectives: Relatively few studies involving the physicochemical properties of crystalline, nanometer-sized particulate gadolinium complexes have been reported. This is in part because of the challenges associated with making nanoparticulate gadolinium suspensions that are stable in aqueous solution. Small particulate gadolinium oxide (SPGO) and SPGO embedded in albumin microspheres (gadolinium oxide albumin microspheres, GOAM), have been used experimentally as prototype contrast agents for multimodality imaging.

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