Mechanical Development and Functional Mechanosensitivity During Early Cardiogenesis

This thesis addresses the questions of when and how mechanical stiffness arises during embryonic heart development and how mechanics affects early cardiomyocyte and myocardium contractile function and cytoskeletal organization. Previous studies addressing how mechanics influence the contractile and electrochemical capacity of mature cardiomyocytes on compliant substrates are reviewed in light of theory explaining how contractile striated fibers might optimally align on intermediate substrates. Embryonic heart and brain tissue stiffness through early development are measured by micropipette aspiration, and the earliest functional heart is found to be three-fold stiffer than early embryonic tissue while brain remains soft. Contraction strain in intact embryonic day 4 (E4) heart tubes shows an optimum relative to hearts with softened or stiffened extracellular matrices. Contraction wave velocity, however, goes linearly with softening or stiffening of tissue, consistent with a theory. Isolated E4 cardiomyocytes cultured on collagen-coated substrates of various stiffnesses show optimal contraction on substrates that match the stiffness of E4 tissue. Sarcomere organization shows optimal organization in intact tissue relative to soft and on intermediate substrates relative to soft or very stiff. The feedback between matrix stiffness and contractile capacity of cardiomyocytes in developing heart tissue is modeled and extended to include interactions with nuclear structural proteins, Lamins. A method for perturbing and imaging nuclear lamina in vivo is discussed and preliminary measurements indicate that the nucleus could act as a measure for intracellular stresses

Optimization of albumin 5% use in a community hospital

Background: The debate surrounding the use of crystalloids versus colloids remains a source of controversy due to limited and conflicting evidence. Emerging data favors the use of crystalloids over colloids in addition to cost benefits. Baptist Hospital of Miami (BHM) has evidence-based guidance for albumin 5%, but it is unclear the degree of appropriate usage. The purpose of this study is to assess the prescribing practices of albumin 5% at BHM and optimize appropriate use through pharmacy driven interventions. Methodology: A single-center, IRB-reviewed, bi-phasic study was conducted within a community hospital. In phase I, a retrospective chart review of patients who received albumin 5% during 2019 was conducted to evaluate prescribing patterns. Phase II was performed after pharmacy driven education was completed to increase appropriate use. A pharmacist was on-call for the prospective chart review to assess appropriateness of albumin 5% orders in patients who met inclusion criteria. The primary outcome is the comparison of appropriate usage of albumin 5% before and after education. Secondary outcomes include pharmacist interventions and the financial impact. Results: After implementation of the albumin 5% stewardship initiative, inappropriate use of albumin 5% was decreased significantly by 54%. Through the 30-day interventional phase, a total of 13 pharmacy interventions were performed with 100% acceptance rate including optimization of crystalloid resuscitation or discontinuation of fluids completely. These interventions along with provider education resulted in at least 72 albumin 5% doses avoided during the phase II study period, which amounts to an extrapolated annual cost savings of ~ $32,400. Conclusion: Introduction of evidence-based guidance in conjugation with prospective pharmacist review and intervention can facilitate the optimization of albumin 5% use. These results demonstrate shifting towards a more evidence-based practice, which ultimately will increase patient’s safety and enhance quality of care

Perceptions of Safety within Residence Halls at a Midwestern College Campus

Sexual violence is a widespread issue in American society. Though sexual violence takes many forms, the topic of campus sexual violence is especially pressing as it has occupied a fair amount of controversy in American media. The experience of sexual violence for college students is often traumatic as they navigate through the administrative systems and criminal justice systems of their respective communities. From a feminist perspective, students that become victims of campus sexual violence are often met with institutional resistance and inadequacies. The purpose of this study was to assess college students’ feelings of safety in residence halls. This research surveyed students in introductory-level Gender and Women’s Studies courses at a Midwestern college campus and sought knowledge from its students on the topics of campus safety and sexual violence. The findings from this research help to critically address the climate of the college campus from the student\u27s perspective and addresses the intricacies of identities and how those identities shape the experiences of both safety and violence

Case Report: An MRI Traumatic Brain Injury Longitudinal Case Study at 7 Tesla: Pre- and Post-injury Structural Network and Volumetric Reorganization and Recovery.

Importance: A significant limitation of many neuroimaging studies examining mild traumatic brain injury (mTBI) is the unavailability of pre-injury data. Objective: We therefore aimed to utilize pre-injury ultra-high field brain MRI and compare a collection of neuroimaging metrics pre- and post-injury to determine mTBI related changes and evaluate the enhanced sensitivity of high-resolution MRI. Design: In the present case study, we leveraged multi-modal 7 Tesla MRI data acquired at two timepoints prior to mTBI (23 and 12 months prior to injury), and at two timepoints post-injury (2 weeks and 8 months after injury) to examine how a right parietal bone impact affects gross brain structure, subcortical volumetrics, microstructural order, and connectivity. Setting: This research was carried out as a case investigation at a single primary care site. Participants: The case participant was a 38-year-old female selected for inclusion based on a mTBI where a right parietal impact was sustained. Main outcomes: The main outcome measurements of this investigation were high spatial resolution structural brain metrics including volumetric assessment and connection density of the white matter connectome. Results: At the first scan timepoint post-injury, the cortical gray matter and cerebral white matter in both hemispheres appeared to be volumetrically reduced compared to the pre-injury and subsequent post-injury scans. Connectomes produced from whole-brain diffusion-weighted probabilistic tractography showed a widespread decrease in connectivity after trauma when comparing mean post-injury and mean pre-injury connection densities. Findings of reduced fractional anisotropy in the cerebral white matter of both hemispheres at post-injury time point 1 supports reduced connection density at a microstructural level. Trauma-related alterations to whole-brain connection density were markedly reduced at the final scan timepoint, consistent with symptom resolution. Conclusions and Relevance: This case study investigates the structural effects of traumatic brain injury for the first time using pre-injury and post-injury 7 Tesla MRI longitudinal data. We report findings of initial volumetric changes, decreased structural connectivity and reduced microstructural order that appear to return to baseline 8 months post-injury, demonstrating in-depth metrics of physiological recovery. Default mode, salience, occipital, and executive function network alterations reflect patient-reported hypersomnolence, reduced cognitive processing speed and dizziness

Genome-Wide DNA Methylation Profiling of Human Diabetic Peripheral Neuropathy in Subjects with Type 2 Diabetes Mellitus

DNA methylation is an epigenetic mechanism important for the regulation of gene expression, which plays a vital role in the interaction between genetic and environmental factors. Aberrant epigenetic changes are implicated in the pathogenesis of diabetes and diabetic complications, but the role of DNA methylation in diabetic peripheral neuropathy (DPN) is not well understood. Therefore, our aim in this study was to explore the role of DNA methylation in the progression of DPN in type 2 diabetes. We compared genome-wide DNA methylation profiles of human sural nerve biopsies from subjects with stable or improving nerve fibre counts to biopsies from subjects with progressive loss of nerve fibres. Nerve fibre counts were determined by comparing myelinated nerve fibre densities between an initial and repeat biopsy separated by 52 weeks. Subjects with significant nerve regeneration (regenerators) and subjects with significant nerve degeneration (degenerators) represent the two extreme DPN phenotypes. Using reduced representation bisulfite sequencing, we identified 3,460 differentially methylated CpG dinucleotides between the two groups. The genes associated with differentially methylated CpGs were highly enriched in biological processes that have previously been implicated in DPN such as nervous system development, neuron development, and axon guidance, as well as glycerophospholipid metabolism and mitogen-activated protein kinase (MAPK) signalling. These findings are the first to provide a comprehensive analysis of DNA methylation profiling in human sural nerves of subjects with DPN and suggest that epigenetic regulation has an important role in the progression of this prevalent diabetic complication

Approaching the uncultured endosymbiont of Riftia pachyptila by physiological proteomics

Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of AAAS for personal use, not for redistribution. The definitive version was published in Science 315 (2007): 247-250, doi:10.1126/science.1132913.The bacterial endosymbiont of the deep-sea tube worm Riftia pachyptila has never been successfully cultivated outside its host. In the absence of cultivation data we have taken a proteomic approach based on the metagenome sequence to study the metabolism of this peculiar microorganism in detail. As one result, we found that three major sulfide oxidation proteins constitute ~12% of the total cytosolic proteome, highlighting the essential role of these enzymes for the symbiont’s energy metabolism. Unexpectedly, the symbiont uses the reductive tricarboxylic acid (TCA) cycle in addition to the previously identified Calvin cycle for CO2 fixation.This work was supported by the DFG, grant Schw595/3-1. Other funding sources were: NSF (OCE 04-52333) and NASA Astrobiology Institute (NNA04CC04A) for SMS, MH: postdoctoral scholarship from WHOI, HF: Academic Senate (RF811S and RE518S)

Identification of and Molecular Basis for SIRT6 Loss-of-Function Point Mutations in Cancer

SummaryChromatin factors have emerged as the most frequently dysregulated family of proteins in cancer. We have previously identified the histone deacetylase SIRT6 as a key tumor suppressor, yet whether point mutations are selected for in cancer remains unclear. In this manuscript, we characterized naturally occurring patient-derived SIRT6 mutations. Strikingly, all the mutations significantly affected either stability or catalytic activity of SIRT6, indicating that these mutations were selected for in these tumors. Further, the mutant proteins failed to rescue sirt6 knockout (SIRT6 KO) cells, as measured by the levels of histone acetylation at glycolytic genes and their inability to rescue the tumorigenic potential of these cells. Notably, the main activity affected in the mutants was histone deacetylation rather than demyristoylation, pointing to the former as the main tumor-suppressive function for SIRT6. Our results identified cancer-associated point mutations in SIRT6, cementing its function as a tumor suppressor in human cancer

Motion-Sensitive 3-D Optical Coherence Microscope Operating at 1300 nm for the Visualization of Early Frog Development

We present 3-dimensional volume-rendered in vivo images of developing embryos of the African clawed frog Xenopus laevis taken with our new en-face-scanning, focus-tracking OCM system at 1300 nm wavelength. Compared to our older instrument which operates at 850 nm, we measure a decrease in the attenuation coefficient by 33%, leading to a substantial improvement in depth penetration. Both instruments have motion-sensitivity capability. By evaluating the fast Fourier transform of the fringe signal, we can produce simultaneously images displaying the fringe amplitude of the backscattered light and images showing the random Brownian motion of the scatterers. We present time-lapse movies of frog gastrulation, an early event during vertebrate embryonic development in which cell movements result in the formation of three distinct layers that later give rise to the major organ systems. We show that the motion-sensitive images reveal features of the different tissue types that are not discernible in the fringe amplitude images. In particular, we observe strong diffusive motion in the vegetal (bottom) part of the frog embryo which we attribute to the Brownian motion of the yolk platelets in the endoderm

The PROblem Gambling RESearch Study (PROGRESS) research protocol: a pragmatic randomised controlled trial of psychological interventions for problem gambling.

INTRODUCTION: International prevalence rates for problem gambling are estimated at 2.3%. Problem gambling is a serious global public health concern due to adverse personal and social consequences. Previous research evaluating the effectiveness of psychological interventions for the treatment of problem gambling has been compromised by methodological limitations, including small sample sizes and the use of waitlist control groups. This article describes the study protocol for a pragmatic randomised controlled trial (RCT) evaluating the effectiveness of cognitive-behavioural therapy (CBT), behaviour therapy (BT), motivational interviewing (MI) against a non-directive supportive therapy (NDST) control, in treating problem gambling. METHODS AND ANALYSIS: This study was a mixed-methods design, with a parallel group, pragmatic RCT as the primary component, and embedded qualitative studies conducted alongside. A total of 297 participants were recruited from the community in Victoria, Australia. Individuals aged 18 years and over, could communicate in English and wished to receive treatment for a gambling problem were eligible. Participants were randomly allocated in to 1 of the 4 psychological interventions: CBT, BT, MI and NDST. Repeated measures were conducted at pretreatment and post-treatment, and 6 and 12 months post-treatment. The statistical analysis will use an intention-to-treat approach. Multilevel mixed modelling will be used to examine changes in the primary outcome measures: gambling symptom severity, using the Gambling Symptom Assessment Scale, and gambling behaviours (frequency, time and expenditure). Secondary outcomes are depression, anxiety, stress and alcohol use. Individual semistructured qualitative interviews were conducted at pretreatment and post-treatment and 12 months post-treatment for a subset of participants (n=66). ETHICS AND DISSEMINATION: This study was approved by the Victorian Department of Justice, Monash University and the University of Melbourne Human Research Ethics Committees. Findings will be reported in a government report, peer-reviewed publications and conference presentations