Translating intracellular calcium signaling into models

The rich experimental data on intracellular calcium has put theoreticians in an ideal position to derive models of intracellular calcium signaling. Over the last 25 years, a large number of modeling frameworks have been suggested. Here, I will review some of the milestones of intracellular calcium modeling with a special emphasis on calcium-induced calcium release (CICR) through inositol-1,4,5-trisphosphate and ryanodine receptors. I will highlight key features of CICR and how they are represented in models as well as the challenges that theoreticians face when translating our current understanding of calcium signals into equations. The selected examples demonstrate that a successful model provides mechanistic insights into the molecular machinery of the Ca2+ signaling toolbox and determines the contribution of local Ca2+ release to global Ca2+ patterns, which at the moment cannot be resolved experimentally

Advantages of Percutaneous Endoscopic Gastrostomy Tube Placement in Patients with Head and Neck Cancer who Receive Radiation as Part of Their Treatment

The use of percutaneous endoscopic gastrostomy tubes as an intervention strategy in head and neck cancer was investigated in this retrospective chart review. Twenty-five veterans met the inclusion criteria and were categorized into two groups – use of prophylactic percutaneous endoscopic gastrostomy and absence of percutaneous endoscopic gastrostomy tube placement. Medical charts were reviewed and data extracted included weight, swallow function, swallow exercise compliance, and physical and social quality of life for 2 years post-treatment. Month-to-month data were compared across the two groups with respect to weight, swallow function, swallow exercise compliance, and physical and social quality of life scores. While both groups had similar weight loss during radiation, the percutaneous endoscopic gastrostomy group had faster recovery to baseline. The percutaneous endoscopic gastrostomy group had greater swallow deficits and better exercise compliance than the absence of percutaneous endoscopic gastrostomy group. More research is needed to guide clinical decision making for the use of percutaneous endoscopic gastrostomy tubes to offset the effects of radiation on patients with head and neck cancer

Transdisciplinary Learning: Investigating the Effects of an Adult Learning Class with a Neuroeducation Perspective on Adult Learners’ Identity, Perceptions of Learning, and Implementation Strategies

Research shows that educators’ perceptions of learning are limited due to a variety of factors which include: a lack of neurobiological- and language acquisition-informed content and information incorporated within teacher preparation programs, educators’ learning experiences grounded in familiarity, and confusions between common educational learning frameworks, andragogy and pedagogy (i.e., K-12), surrounding appropriate learning tenets and effective learning practices for different-aged learners. However, one transdisciplinary model, neuroeducation, incorporates learning literatures from cognitive psychology, neuroscience, and language acquisition and provides insight into the limitations of educators’ perceptions of learning and effective instructional practice. This study investigates the extent to which adults participating in a semester long course on adult learning theory with a neuroeducation approach to learning experienced changes in (a) perceptions of their identity; (b) perceptions of learning theory in professional and personal settings; (c) professional and personal implementation of learning theories; and (d) the perceived impacts of their implementations on those in their professional and personal settings. A narrative inquiry design captured responses from two groups of participants’ semistructured interview questions demonstrating that a neuroeducation perspective of learning positively impacted adult learners’ identity, altered their perceptions of learning for K-12 learners and for adult learners, led to implementation of visual-based learning strategies grounded in neuroeducation perspectives, motivated their colleagues to implement instructional changes, and positively impacted K-12 learners’ social and cognitive growth. Findings from this study signify a need for neuroeducation perspectives of learning within all levels of public and private education

Time to blip – stochastic simulation of single channel opening

The stochastic dynamics of the inositol-1,4,5-trisphosphate (IP3) receptor (IP3R) is key to understanding a wide range of observed calcium (Ca2+) signals (Falcke 2004). The stochastic nature results from the constant binding and unbinding of Ca2+ and IP3 to and from their respective binding sites and is especially important in the initiation of a Ca2+ puff, i.e. the release of Ca2+ through a cluster of IP3Rs. Once the first IP3R opens, the Ca2+ concentration rises significantly around the ion channel and hence increases the open probability for neighboring IP3Rs. In turn this may trigger the activation of further receptors giving rise to a Ca2+ puff (Thul et al. 2009; Thurley et al. 2012). In this protocol, we determine the time that it takes for a single IP3R to open from rest. We explicitly take into account the tetrameric structure of the IP3R and the fact that multiple subunits need to be active before the channel opens (Bezprozvanny et al. 1991; Watras et al. 1991). We develop code for a stochastic simulation of the IP3R and simulate it using the software package Matlab (Attaway 2011). This protocol demonstrates the basic form of a stochastic simulation algorithm and may serve as a starting point to investigate more complex gating dynamics

Oscillations in a point models of the intracellular Ca2+ concentration

Oscillations in the intracellular calcium (Ca2+) concentration form one of the main pathways by which cells translate external stimuli into physiological responses (Thul et al. 2008; Dupont et al. 2011; Parekh 2011). The mechanisms that underlie the generation of Ca2+ oscillations are still actively debated in the modeling community, but there is growing evidence that Ca2+ oscillations result from the spatio-temporal summation of subcellular Ca2+ release events (Thurley et al. 2012). Nevertheless, one prominent modeling approach to intracellular Ca2+ oscillations is the use of ordinary differential equations (ODEs), which treat the intracellular Ca2+ concentration as spatially homogenous. Although ODEs cannot account for the interaction of Ca2+ microdomains to form cell-wide Ca2+ patterns, modelers still choose ODEs since (a) the study of ODEs is computationally cheap, and a large body of techniques is available to investigate ODEs in great detail, or (b) there might not be sufficient experimental data to develop a spatially extended model. Irrespective of the reason, analyzing ODEs is a key instrument in the toolbox of modelers. In this protocol, we look at a wellknown model for Ca2+ oscillations (De Young and Keizer 1992; Li and Rinzel 1994). The main emphasis of this protocol is the use of the open source software package XPPaut to numerically study ODEs (Ermentrout 2002). The knowledge gained here can be directly transferred to other ODE systems and therefore may serve as a template for future studies. For a general background on analysing ODEs in the context of Mathematical Cell Physiology, I refer the reader to (Keener and Sneyd 2001; Fall et al. 2002; Britton 2002; Murray 2013)

Central Venous Catheter Complications during Home Parenteral Nutrition: A Prospective Pilot Study of 481 Patients with More than 30,000 Catheter Days

Background: Home parenteral nutrition (HPN) has been shown to delay deterioration in cancer patients with malnutrition. Its risk-benefit ratio, however, is determined by the threat of central venous catheter (CVC) complications. Only few prospective studies on this subject exist, most of them based on small samples. The objective of this study was to provide reliable estimates of incidence rates of CVC complications in everyday HPN patient care in Germany. Patients and Methods: Aiming for a large prospective cohort study, we cooperated with a service provider caring for HPN patients nationwide. Between July 1 and November 30, 2006, all consecutive adult patients with more than 10 infusion days and no previous history of HPN were recruited. Follow-up ended on January 31, 2007. Data were collected in a standardised way by the provider's staff. To prevent underreporting, we used computer-assisted telephone interviews with medical caregivers as a provider-independent data source. Results: 481 patients met the inclusion criteria, contributing a total of 31,337 catheter days. 52 patients experienced a total of 63 CVC complications, resulting in an incidence rate of 2.01 CVC complications per 1,000 catheter days including 1.02 CVC infections per 1,000 catheter days. Conclusion: HPN administration can be safely performed with a relatively low rate of CVC complications

Faculty Rating of Administration Committee report, 2016-2017

Annual report for a committee of the University of Tennessee at Chattanooga Faculty Senate

Studium and Punctum: The Duality of Photography

What defines greatness? What element can change something from being mildly interesting to extraordinary? Details, emotion, back-story, and message can all add to the power of a photo, but these are all reasonable answers to define something unreasonable. Recognizing something powerful is instinctive, which makes it hard to define. Barthes gives some guidance to this process by separating the vaguely interesting from the piercingly wonderful. Through studium and punctum, images are separated into these categories, allowing the viewer to analyze images with acute precision. What makes this interesting? Why do I care? These questions are slowly answered by looking deeply into what interests you as a person and figuring out why