411 research outputs found
Discussing Race, Policing, and Privilege in a High School Classroom
This article describes a unit implemented in a ninth-grade English classroom using the young adult novel, All American Boys (Reynolds & Keily, 2015) to explore issues of police brutality, privilege, and racism. Pedagogical activities are offered alongside a critical reflection of the unit as the author explores difficult moments while teaching. Implications for English educators and currently practicing ELA teachers are provided with suggestions on how to revise the unit to center on exploring the systematic oppression of people of color
Cyanobacterial Neurotoxin Ξ²-N-Methylamino-L-alanine (BMAA) in Shark Fins
Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin Ξ²-N-methylamino-L-alanine (BMAA) has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA
Collider Bias Is Only a Partial Explanation for the Obesity Paradox
Background: βObesity paradoxβ refers to an association between
obesity and reduced mortality (contrary to an expected increased
mortality). A common explanation is collider stratification bias:
unmeasured confounding induced by selection bias. Here, we test
this supposition through a realistic generative model.
Methods: We quantify the collider stratification bias in a selected
population using counterfactual causal analysis. We illustrate the bias
for a range of scenarios, describing associations between exposure
(obesity), outcome (mortality), mediator (in this example, diabetes)
and an unmeasured confounder.
Results: Collider stratification leads to biased estimation of the
causal effect of exposure on outcome. However, the bias is small relative
to the causal relationships between the variables.
Conclusions: Collider bias can be a partial explanation of the obesity
paradox, but unlikely to be the main explanation for a reverse
direction of an association to a true causal relationship. Alternative
explanations of the obesity paradox should be explored. See Video
Abstract at http://links.lww.com/EDE/B51
The Cyanobacteria Derived Toxin Beta-N-Methylamino-L-Alanine and Amyotrophic Lateral Sclerosis
There is mounting evidence to suggest that environmental factors play a major role in the development of neurodegenerative diseases like ALS (Amyotrophic Lateral Sclerosis). The non-protein amino acid beta-N-methylamino-L-alanine (BMAA) was first associated with the high incidence of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) in Guam, and has been implicated as a potential environmental factor in ALS, Alzheimerβs disease, and other neurodegenerative diseases. BMAA has a number of toxic effects on motor neurons including direct agonist action on NMDA and AMPA receptors, induction of oxidative stress, and depletion of glutathione. As a non-protein amino acid, there is also the strong possibility that BMAA could cause intraneuronal protein misfolding, the hallmark of neurodegeneration. While an animal model for BMAA-induced ALS is lacking, there is substantial evidence to support a link between this toxin and ALS. The ramifications of discovering an environmental trigger for ALS are enormous. In this article, we discuss the history, ecology, pharmacology and clinical ramifications of this ubiquitous, cyanobacteria-derived toxin
A Conceptual Model for Teaching Social Responsibility and Health Advocacy: An Ambulatory/Community Experience (ACE)
Background: At a macro level, Social Responsibility and Social Accountability are explicit priorities for medical schools in Canada and internationally, although the advancement of this vision is still developing. At a micro level, Health Advocacy is important for physicians-in-training as well as practicing physicians. The conceptual model being proposed is that Social Responsibility is connected to mastering Health Advocacy. The University of Toronto Faculty of Medicine has 16 years of experience through a mandatory 4th year clerkship course entitled the Ambulatory/Community Experience (ACE) which from inception emphasized Social Responsibility and Health Advocacy. The objective of this retrospective study was to provide a model to support the acquisition of Health Advocacy and the development of socially responsible medical students.Methods: A conceptual model with three distinct elements: 1) ambulatory/community placements, 2) individual pedagogical approaches and 3) narrative, reflective assignments was applied.Results: The three elements of the model, all based on the five ACE learning domains (objectives) and embedded in CanMEDS type competencies, are effective and appear to supportΒ achievement of competency in Health Advocacy.Conclusion: A model which includes vetted ambulatory/community placements, individual pedagogical approaches, and narrative reflective assignments based on objectives with a Health Advocate perspective appears to encourage Social Responsibility in medical students
Production of the Neurotoxin BMAA by a Marine Cyanobacterium
Diverse species of cyanobacteria have recently been discovered to produce the neurotoxic non-protein amino acid Ξ²-methylamino-L-alanine (BMAA). In Guam, BMAA has been studied as a possible environmental toxin in the diets of indigenous Chamorro people known to have high levels of Amyotrophic Lateral Sclerosis/ Parkinsonism Dementia Complex (ALS/PDC). BMAA has been found to accumulate in brain tissues of patients with progressive neurodegenerative illness in North America. In Guam, BMAA was found to be produced by endosymbiotic cyanobacteria of the genus Nostoc which live in specialized cycad roots. We here report detection of BMAA in laboratory cultures of a free-living marine species of Nostoc. We successfully detected BMAA in this marine species of Nostoc with five different methods: HPLC-FD, UPLC-UV, Amino Acid Analyzer, LC/MS, and Triple Quadrupole LC/MS/MS. This consensus of five different analytical methods unequivocally demonstrates the presence of BMAA in this marine cyanobacterium. Since protein-associated BMAA can accumulate in increasing levels within food chains, it is possible that biomagnification of BMAA could occur in marine ecosystems similar to the biomagnification of BMAA in terrestrial ecosystems. Production of BMAA by marine cyanobacteria may represent another route of human exposure to BMAA. Since BMAA at low concentrations causes the death of motor neurons, low levels of BMAA exposure may trigger motor neuron disease in genetically vulnerable individuals
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