Modeling the Pancreatic α-Cell: Dual Mechanisms of Glucose Suppression of Glucagon Secretion

AbstractThe mechanism by which glucose induces insulin secretion in β-cells is fairly well understood. Despite years of research, however, the mechanism of glucagon secretion in α-cells is still not well established. It has been proposed that glucose regulates glucagon secretion by decreasing the conductance of either outward ATP-dependent potassium channels (K(ATP)) or an inward store-operated current (SOC). We have developed a mathematical model based on mouse data to test these hypotheses and found that both mechanisms are possible. Glucose metabolism closes K(ATP) channels, which depolarizes the cell but paradoxically reduces calcium influx by inactivating voltage-dependent calcium and sodium channels and decreases secretion. Glucose metabolism also activates SERCA pumps, which fills the endoplasmic reticulum and hyperpolarizes the cells by reducing the inward current through SOC channels and again suppresses glucagon secretion. We find further that the two mechanisms can combine to account for the nonmonotonic dependence of secretion on glucose observed in some studies, an effect that cannot be obtained with either mechanism alone

Interview 1998.10 Margaret Brown and Larine Watts

In this interview, Margaret Brown and Larine Watts speak on the civil rights movement in Prince Edward County, the school closings and their reactions, especially as parents. Additionally, they talked about their experiences with working in segregated businesses and the difficult decision to relocate their families to New Jersey for their children\u27s education. Conducted by Jessica Williams, Stephanie Reitz, and Rebecca Dixon. Transcribed by Sarah Ferguson. Audio skips and is not great quality

Inflammation as a potential mediator for the association between periodontal disease and Alzheimer’s disease

Periodontal disease (PDD) is associated with increased risk of cardiovascular disease, cerebrovascular disease, and mortality in many studies, while other studies have begun to suggest an association of PDD with Alzheimer’s disease (AD). This paper discusses how infectious pathogens and systemic infection may play a role in AD. The roles of infection and inflammation are addressed specifically with regard to known AD pathologic lesions including senile plaques, neuron death, neurofibrillary tangles, and cerebrovascular changes. A testable model of proposed pathways between periodontal infection and AD is presented including three possible mechanisms: a) direct effects of infectious pathogens, b) inflammatory response to pathogens, and c) the effects on vascular integrity. The role of gene polymorphisms is discussed, including apolipoprotein (APOE) ɛ4 as a pro-inflammatory and pro-infection genotype

Inflammation as a potential mediator for the association between periodontal disease and Alzheimer’s disease

This is the publisher's version, also available electronically from http://www.dovepress.com/inflammation-as-a-potential-mediator-for-the-association-between-perio-peer-reviewed-article-NDT.Periodontal disease (PDD) is associated with increased risk of cardiovascular disease, cerebrovascular disease, and mortality in many studies, while other studies have begun to suggest an association of PDD with Alzheimer’s disease (AD). This paper discusses how infectious pathogens and systemic infection may play a role in AD. The roles of infection and inflammation are addressed specifically with regard to known AD pathologic lesions including senile plaques, neuron death, neurofibrillary tangles, and cerebrovascular changes. A testable model of proposed pathways between periodontal infection and AD is presented including three possible mechanisms: a) direct effects of infectious pathogens, b) inflammatory response to pathogens, and c) the effects on vascular integrity. The role of gene polymorphisms is discussed, including apolipoprotein (APOE) ε4 as a pro-inflammatory and pro-infection genotype

Loss and grief in the workplace. What can we learn from the literature?

Purpose – The purpose of this paper is to determine how Australian workplaces, their managers and employees respond to those who are grieving at work, as a result of chronic or terminal illness, or caring for those with chronic or terminal illness. The review draws on Australian and relevant international literature and seeks to answer this question. Design/methodology/approach – A literature review was undertaken in preparation for an Australian study examining workplace supports for people who are grieving – because they are carers, have experienced a death, or are balancing their own illness with their work. Using a range of search terms, the literature was searched for relevant work between 1980 and 2010. The search found examples of workplace supports throughout the world and some developing Australian literature. Findings – Despite illness and death occurring at any stage of a person\u27s life, there is little research that identifies workplace issues associated with grief and loss. And while workplace legislation allows for minimal supports, there was evidence that some workplaces have begun to offer flexibility for work life balance. Practical implications – Effective workplace supports will involve individual and workplace responses, but also require legislative approaches in order to effect broad-based system change. Originality/value – The paper compares Australian and international literature about workplace supports and provides an overview of the issues arising

The COVID-19 Crisis: Using the Cracks in Neoliberalism for Social Transformation Towards a More Just Society

Within the current COVID-19 pandemic, cracks observed in neoliberal dominant global economic paradigms reveal how austerity policies have crippled crucial social safety nets, such as health care, with capitalism continuing to adversely impact our climate with ad infinitum extraction of resources for overconsumption. In examining these associations, this collaborative paper critically applies social theories to explore ideas and approaches to creating transformative social change, in an effort to move towards a more just and sustainable society in the context of the COVID-19 pandemic and other ongoing systemic crises. The paper presents the pandemic as a social crisis and explores theories of social justice and how they might be applied within the context of neoliberal capitalism, also known as neoliberalism. The authors of this paper argue that to move towards a just society, social transformation is needed, informed by the theories of decoloniality and intersectionality. A conceptual model is presented that demonstrates how these theories can be woven together to inform community psychology action and research, addressing COVID-19 specifically. Possibilities for transformation in the areas of mental health and climate justice are also presented. Finally, recommendations for community psychology researchers seeking social transformation, while navigating this challenging and complex new reality, are shared

The COVID-19 Crisis: Using the Cracks in Neoliberalism for Social Transformation Towards a More Just Society

Within the current COVID-19 pandemic, cracks observed in neoliberal dominant global economic paradigms reveal how austerity policies have crippled crucial social safety nets, such as health care, with capitalism continuing to adversely impact our climate with ad infinitum extraction of resources for overconsumption. In examining these associations, this collaborative paper critically applies social theories to explore ideas and approaches to creating transformative social change, in an effort to move towards a more just and sustainable society in the context of the COVID-19 pandemic and other ongoing systemic crises. The paper presents the pandemic as a social crisis and explores theories of social justice and how they might be applied within the context of neoliberal capitalism, also known as neoliberalism. The authors of this paper argue that to move towards a just society, social transformation is needed, informed by the theories of decoloniality and intersectionality. A conceptual model is presented that demonstrates how these theories can be woven together to inform community psychology action and research, addressing COVID-19 specifically. Possibilities for transformation in the areas of mental health and climate justice are also presented. Finally, recommendations for community psychology researchers seeking social transformation, while navigating this challenging and complex new reality, are shared

Investigating How Calcium Diffusion Affects Metabolic Oscillations and Synchronization of Pancreatic Beta Cells

Diabetes is a disease characterized by improper concentrations of blood glucose due to irregular insulin production or sensitivity. Coupled in islets of Langerhans within the pancreas, β-cells are responsible for the production and regulation of insulin based on changes in glucose levels. Using the Dual Oscillator Model (DOM), we will examine how calcium handling between individual pancreatic β-cells affects the synchronization of metabolic oscillations within electrically coupled islets. Calcium permeability was implemented into the DOM, and numerical solutions of the system were obtained via MATLAB using a modified ordinary differential equation solver for stiff systems and the Automatic Differentiation for MATLAB software. We developed a synchronization index to quantitatively describe the synchronization of variables between nearest neighboring cells and throughout the islet as a whole. We considered how calcium permeability between heterogeneous cells affects the behavior of metabolic oscillations and their synchronization. In particular, we examined fructose-1, 6-bisphosphate. In our study metabolic oscillations were always maintained. We also showed that, for low to moderate levels of electrical coupling, calcium permeability increased the synchronization index, but increasing calcium permeability had little effect on synchronization when cells were already strongly synchronized with strong electrical coupling. Heterogeneity due to glucose influx or initial state of the cells had similar synchronization results