Rethinking norms in educational practices to promote appreciation of variation: Lessons from human anatomy

Across disciplines, teaching approaches and educational resources that are based on norms prevail—a norm is defined as a standard or typical practice, convention, or procedure. Although norms often have a historical basis and may be used to simplify complex content, their frequent use in education often disregards and disvalues variation. Variation can present valuable learning opportunities for students, promoting the development of problem solving and critical thinking skills, and humanizing their learning. An example of norms and variation in the discipline of gross anatomy is the frequent use of the “standard human body” in teaching. This idealized view typically does not account for anatomical variations despite their prevalence across the human population. This practice can contribute to alienation within gross anatomy classrooms, with students not feeling represented in the images and terms that they are exposed to. The main aim of this study is to investigate the impact of anatomical variations in gross anatomy courses to inform the creation of updated educational resources. A scoping review was conducted to explore teaching approaches for, and student outcomes of, including anatomical variations in undergraduate, graduate, and professional gross anatomy courses. Scoping reviews are a valuable approach in educational research to systematically explore available evidence related to a problem, elucidate knowledge gaps, and inform updated inclusive practices. Awareness of the norms present in one’s discipline can inform the intentional inclusion of variations in educational approaches and resources, contributing to the inclusion and appreciation of diversity within and across fields of study

Clinical field-strength MRI of amyloid plaques induced by low-level cholesterol feeding in rabbits

Two significant barriers have limited the development of effective treatment of Alzheimer's disease. First, for many cases the aetiology is unknown and likely multi-factorial. Among these factors, hypercholesterolemia is a known risk predictor and has been linked to the formation of β-amyloid plaques, a pathological hallmark this disease. Second, standardized diagnostic tools are unable to definitively diagnose this disease prior to death; hence new diagnostic tools are urgently needed. Magnetic resonance imaging (MRI) using high field-strength scanners has shown promise for direct visualization of β-amyloid plaques, allowing in vivo longitudinal tracking of disease progression in mouse models. Here, we present a new rabbit model for studying the relationship between cholesterol and Alzheimer's disease development and new tools for direct visualization of β-amyloid plaques using clinical field-strength MRI. New Zealand white rabbits were fed either a low-level (0.125–0.25% w/w) cholesterol diet (n = 5) or normal chow (n = 4) for 27 months. High-resolution (66 × 66 × 100 µm3; scan time = 96 min) ex vivo MRI of brains was performed using a 3-Tesla (T) MR scanner interfaced with customized gradient and radiofrequency coils. β-Amyloid-42 immunostaining and Prussian blue iron staining were performed on brain sections and MR and histological images were manually registered. MRI revealed distinct signal voids throughout the brains of cholesterol-fed rabbits, whereas minimal voids were seen in control rabbit brains. These voids corresponded directly to small clusters of extracellular β-amyloid-positive plaques, which were consistently identified as iron-loaded (the presumed source of MR contrast). Plaques were typically located in the hippocampus, parahippocampal gyrus, striatum, hypothalamus and thalamus. Quantitative analysis of the number of histologically positive β-amyloid plaques (P < 0.0001) and MR-positive signal voids (P < 0.05) found in cholesterol-fed and control rabbit brains corroborated our qualitative observations. In conclusion, long-term, low-level cholesterol feeding was sufficient to promote the formation of extracellular β-amyloid plaque formation in rabbits, supporting the integral role of cholesterol in the aetiology of Alzheimer's disease. We also present the first evidence that MRI is capable of detecting iron-associated β-amyloid plaques in a rabbit model of Alzheimer's disease and have advanced the sensitivity of MRI for plaque detection to a new level, allowing clinical field-strength scanners to be employed. We believe extension of these technologies to an in vivo setting in rabbits is feasible and that our results support future work exploring the role of MRI as a leading imaging tool for this debilitating and life-threatening disease

Quantification of Morphological Modulation, F-Actin Remodeling, and PECAM-1 (CD-31) Redistribution in Endothelial Cells in Response to Fluid-Induced Shear Stress Under Various Flow Conditions

Cardiovascular diseases (CVDs) are the number one cause of death globally. Arterial endothelial cell (EC) dysfunction plays a key role in many of these CVDs, such as atherosclerosis. Blood flow-induced wall shear stress (WSS), among many other pathophysiological factors, is known to significantly contribute to EC dysfunction. The present study reports an in vitro investigation of the effect of quantified WSS on ECs, analyzing the EC morphometric parameters and cytoskeletal remodeling. The effects of four different flow cases (low steady laminar (LSL), medium steady laminar (MSL), nonzero-mean sinusoidal laminar (NZMSL), and laminar carotid (LCRD) waveforms) on the EC area, perimeter, shape index (SI), angle of orientation, F-actin bundle remodeling, and platelet endothelial cell adhesion molecule-1 (PECAM-1) localization were studied. For the first time, a flow facility was fully quantified for the uniformity of flow over ECs and for WSS determination (as opposed to relying on analytical equations). The SI and angle of orientation were found to be the most flow-sensitive morphometric parameters. A two-dimensional fast Fourier transform (2D FFT) based image processing technique was applied to analyze the F-actin directionality, and an alignment index (AI) was defined accordingly. Also, a significant peripheral loss of PECAM-1 in ECs subjected to atheroprone cases (LSL and NZMSL) with a high cell surface/cytoplasm stain of this protein is reported, which may shed light on of the mechanosensory role of PECAM-1 in mechanotransduction

Broadening the Definition of &lsquo;Research Skills&rsquo; to Enhance Students&rsquo; Competence across Undergraduate and Master&rsquo;s Programs

Undergraduate and master&rsquo;s programs&mdash;thesis- or non-thesis-based&mdash;provide students with opportunities to develop research skills that vary depending on their degree requirements. However, there is a lack of clarity and consistency regarding the definition of a research skill and the components that are taught, practiced, and assessed. In response to this ambiguity, an environmental scan and a literature search were conducted to inform the creation of a comprehensive list of research skills that can be applied across programs and disciplines. Although published studies directly comparing research skills in thesis and non-thesis programs were limited, the specific skills reported in each program type were similar. This viewpoint article identifies the following seven research skills that were most frequently reported across both thesis and non-thesis programs: critical appraisal, information synthesis, decision making, problem solving, data collection, data analysis, and communication. When contextualized appropriately, these skills can be useful for a student during their academic program and are transferable across a range of future career pathways. Broadening the definition of &ldquo;research skills&rdquo; can inform curricular updates and program development, independent of their program type, to ensure that students are presented with explicit opportunities to develop the skills needed to succeed in their educational and occupational endeavours

Broadening the Definition of ‘Research Skills’ to Enhance Students’ Competence across Undergraduate and Master’s Programs

Undergraduate and master’s programs—thesis- or non-thesis-based—provide students with opportunities to develop research skills that vary depending on their degree requirements. However, there is a lack of clarity and consistency regarding the definition of a research skill and the components that are taught, practiced, and assessed. In response to this ambiguity, an environmental scan and a literature search were conducted to inform the creation of a comprehensive list of research skills that can be applied across programs and disciplines. Although published studies directly comparing research skills in thesis and non-thesis programs were limited, the specific skills reported in each program type were similar. This viewpoint article identifies the following seven research skills that were most frequently reported across both thesis and non-thesis programs: critical appraisal, information synthesis, decision making, problem solving, data collection, data analysis, and communication. When contextualized appropriately, these skills can be useful for a student during their academic program and are transferable across a range of future career pathways. Broadening the definition of “research skills” can inform curricular updates and program development, independent of their program type, to ensure that students are presented with explicit opportunities to develop the skills needed to succeed in their educational and occupational endeavours

Wall Shear Stress Determination in a Small-Scale Parallel Plate Flow Chamber Using Laser Doppler Velocimetry Under Laminar, Pulsatile and Low-Reynolds Number Turbulent Flows

The parallel plate flow chamber (PPFC) has gained popularity due to its applications in fields such as biological tissue engineering. However, most of the studies using PPFC refer to theoretical relations for estimating the wall shear stress (WSS) and, hence, the accuracy of such quantifications remains elusive for anything other than steady laminar flow. In the current study, a laser Doppler velocimetry (LDV) method was used to quantify the flow in a PPFC (H = 1.8 mm x W = 17.5 mm, D-h = 3.26 mm, aspect ratio = 9.72) under steady Re = 990, laminar pulsatile (carotid Re0-mean = 282 as well as a non-zero-mean sinusoidal Re0-mean = 45 pulse) and low-Re turbulent Re = 2750 flow conditions. A mini-LDV probe was applied, and the absolute location of the LDV measuring volume with the respect to the wall was determined using a signal monitoring technique with uncertainties being around +/- 627 mu m. The uniformity of the flow across the span of the channel, as well as the WSS assessment for all the flow conditions, was measured with the uncertainties all being less than 16%. At least two points within the viscous sublayer of the low-Re turbulent flow were measured (with the y(+) for the first point \u3c 3) and the WSS was determined using two methods with the differences between the two methods being within 5%. This paper for the first time presents the experimental determination of WSS using LDV in a small-scale PPFC under various flow conditions, the challenges associated with each condition, and a comparison between the cases. The present data will be useful for those conducting biological or numerical modeling studies using such devices. The parallel plate flow chamber (PPFC) has gained popularity due to its applications in fields such as biological tissue engineering. However, most of the studies using PPFC refer to theoretical relations for estimating the wall shear stress (WSS) and, hence, the accuracy of such quantifications remains elusive for anything other than steady laminar flow. In the current study, a laser Doppler velocimetry (LDV) method was used to quantify the flow in a PPFC (H = 1.8 mm x W = 17.5 mm, D-h = 3.26 mm, aspect ratio = 9.72) under steady Re = 990, laminar pulsatile (carotid Re0-mean = 282 as well as a non-zero-mean sinusoidal Re0-mean = 45 pulse) and low-Re turbulent Re = 2750 flow conditions. A mini-LDV probe was applied, and the absolute location of the LDV measuring volume with the respect to the wall was determined using a signal monitoring technique with uncertainties being around +/- 627 mu m. The uniformity of the flow across the span of the channel, as well as the WSS assessment for all the flow conditions, was measured with the uncertainties all being less than 16%. At least two points within the viscous sublayer of the low-Re turbulent flow were measured (with the y(+) for the first point \u3c 3) and the WSS was determined using two methods with the differences between the two methods being within 5%. This paper for the first time presents the experimental determination of WSS using LDV in a small-scale PPFC under various flow conditions, the challenges associated with each condition, and a comparison between the cases. The present data will be useful for those conducting biological or numerical modeling studies using such devices

In Vivo MRI of Amyloid Plaques in a Cholesterol-Fed Rabbit Model of Alzheimer\u27s Disease

Hypercholesterolemia has been identified as a risk factor for Alzheimer\u27s disease. In this study, rabbits were fed either a cholesterol diet or normal chow diet for 24 months. At endpoint, in vivo MRI was performed at the field strength of 3 Tesla using fast imaging employing steady state acquisition without (FIESTA) or with susceptibility-weighted post-processing (SWI-FIESTA) and susceptibility-weighted imaging with multi-echo acquisition (SWAN). This imaging revealed signal voids/hypointensities throughout the cortex, sub-cortex, and hippocampus of cholesterol-fed animals compared to control animals. Quantitative image analysis corroborated these qualitative findings and highlighted that SWI processing of FIESTA images significantly improved the detectability of plaques (p \u3c 0.05). A beta immunostaining and Prussian blue staining for iron demonstrated that the voids in MR images corresponded to iron-laden A beta-positive plaques. This study demonstrates non-invasive in vivo visualization of A beta plaques in a diet-induced large animal model of Alzheimer\u27s disease. This work lays the foundation for future work focusing on longitudinal monitoring of plaque formation in this model and the effects of diet or drug interventions

Vascular smooth muscle cells as a valvular interstitial cell surrogate in heart valve tissue engineering

Background: Vascular smooth muscle cells (VSMCs) are a potential autologous cell source for aortic valve tissue engineering, but have a phenotype that differs from that of valvular interstitial cells in vivo. We hypothesized that combining basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), or platelet-derived growth factor (PDGF) with transforming growth factor beta-1 (TGF-β1) would achieve a valvular interstitial cell-like phenotype of VSMCs. Methods: VSMC phenotype was assessed by immunofluorescence, proliferation was measured by the tetrazolium reduction (MTT) assay, and extracellular matrix gene expression was determined by real-time polymerase chain reaction. Results: Combinations of growth factors that included PDGF showed the greatest increases in proliferation. Immunofluorescence for α-smooth muscle actin demonstrated an inverse correlation between proliferation and a myofibroblast-like phenotype, while combinations of TGF-β1+ EGF+bFGF (TEF) and TGF-β1+EGF+PDGF (TEP) induced the greatest change of α-smooth muscle actin expression compared to untreated controls. Finally, TEP treatment showed an increase in versican, fibronectin, and type I collagen mRNA expression, while decreasing matrix metalloproteinase 1 expression. Conclusions: Combination of TGF-β1 with EGF and PDGF induces VSMC proliferation and expression of extracellular matrix constituents found in the aortic valve. In vitro preconditioning of VSMCs provides a potentially viable surrogate cell source for developing a valve graft. © 2009, Mary Ann Liebert, Inc