Investigating Murine Double Minute-2 Pro-Angiogenic Function in Health and Disease: An Integrative Approach from Rodent and Human Skeletal Muscle to Primary Endothelial Cells

Capillaries are essential for overall skeletal muscle health, transporting nutrients and oxygen as well as removing waste from muscle cells. Angiogenesis is the process of capillary growth from pre-existing capillaries, and is regulated by a balance of pro- and anti-angiogenic factors. Our laboratory has demonstrated that Murine Double Minute-2 (Mdm2) is essential for skeletal muscle capillary maintenance as well as for exercise-induced angiogenesis. The aim of my research was to further investigate Mdm2 function in both physiological (exercise) and pathological (diabetes) contexts at the tissue level of the skeletal muscle and in primary endothelial cells. I first contributed to show that Mdm2 protein levels are elevated following a prolonged exercise training program in human skeletal muscle (academic research paper 1). Next, I investigated the response of Mdm2 to an acute bout of exercise, which itself represents a powerful pro-angiogenic stimulus (academic research paper 2). Muscle contractile activity stimulates Mdm2 phosphorylation on its serine 166 concomitant with increased pro-angiogenic vascular endothelial growth factor-A (VEGF-A). Mdm2 phosphorylation was found to be dependent on VEGF-A signaling, demonstrating for the first time that Mdm2 and VEGF-A can interact in a complex regulatory loop. In vitro experiments show that VEGF-A-dependent activation of Mdm2 leads to increased migratory activity of endothelial cells. This effect appeared to be a result of enhanced Mdm2-FoxO1 binding, resulting in the inhibition of FoxO1-dependent regulation of thrombospondin-1 expression, a potent anti-angiogenic molecule. I further explored this relationship between VEGF-A and Mdm2 in academic research paper 3, demonstrating that VEGF-driven Mdm2 phosphorylation was dependent on extracellular signal related kinases 1/2 (ERK1/2) - p90 ribosomal s6 kinase (p90RSK) in primary human endothelial cells. Finally, academic research paper 4 provided evidence that Mdm2 is a clinically relevant protein in type 1 diabetes (T1D), a highly understudied disease in the context of skeletal muscle angio-regulation. Mdm2 protein abundance was lowered in muscles from T1D animals alongside increases in key anti-angiogenic Mdm2 targets and significant capillary regression. Taken together, my dissertation research clearly identifies Mdm2 as a master regulator of angio-adaptation at the level of the skeletal muscle and endothelial cells in both health and disease

Fine-grain parallelization versus the wavefront method

We develop a technique for extracting parallelism from ordinary (sequential) programs. The technique combines two fine-grain, instruction level code transformations to achieve effects similar to the wavefront method. Such effects were previously available only as transformations at coarser levels of granularity. By integrating the strengths of the wavefront method with the ability to extract fine-grain, irregular parallelism at the instruction level, our technique exploits previously untapped parallelism

Impact of Deferral for Low Hemoglobin on Donor Return

Introduction. A consistent blood supply to support life-saving transfusions relies on regular and repeat volunteer blood donations. In this study, we focused on donors previously deferred for low-hemoglobin (Hb) levels to better understand the value of supplying post-deferral educational information, and the actions donors took based on their deferral. Methods. An anonymous national survey of active and inactive donor groups (10,000 each) was conducted. The survey questions assessed post-deferral donor actions, preferences regarding post deferral education, understanding of their deferral, and demographic information. Chi-square analysis was performed to compare categorical survey results between donor groups with p \u3c 0.05 denoting statistical significance. Results. The survey resulted in 722 and 103 active and inactive donor respons- es, respectively. Active donors were more likely to recall receiving educational materials post-deferral (52% vs. 35%, p=003), take iron and vitamin supplements (54% vs. 39%, p=0.009), lived within 30 min of a donor site (94% vs. 84%, p=0.006), and more likely to be older than 45 yr (62% vs. 42%, p=0.002) than their inactive donor counter- parts. Active and inactive donors were similar (p\u3e0.05) with anemia history frequency, female-gender predominance, low-prevalence of vegans, and mixed interest in receiving information about raising hemoglobin levels. Conclusion. While active donors more frequently recalled receiving educational materials for their low hemoglobin deferral, and were more likely to take action to improve their hemoglobin, an alternative method of post-deferral recruitment should be considered given the uncertain value of post-deferral information when comparing active vs. inactive donors.https://scholarworks.uvm.edu/comphp_gallery/1253/thumbnail.jp

First-order theory of subtyping constraints

We investigate the first-order theory of subtyping constraints. We show that the first-order theory of non-structural subtyping is undecidable, and we show that in the case where all constructors are either unary or nullary, the first-order theory is decidable for both structural and non-structural subtyping. The decidability results are shown by reduction to a decision problem on tree automata. This work is a step towards resolving long-standing open problems of the decidability of entailment for non-structural subtyping

Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a pure replication.

BACKGROUND: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits regarding worm infections and school attendance. Effects were seen among children treated with deworming drugs, untreated children in intervention schools and children in nearby non-intervention schools. Combining these effects, the intervention was reported to increase school attendance by 7.5% in treated children. Effects on other outcomes (worm infections, anaemia, nutritional status and examination performance) were also investigated. METHODS: In this pure replication, we used data provided by the original authors to re-analyse the study according to their methods. We compared these results against those presented in the original paper. RESULTS: Although most results were reproduced as originally reported, we identified discrepancies of several types between the original findings and re-analysis. For worm infections, re-analysis showed reductions similar to those originally reported. For anaemia prevalence, in contrast to the original findings, re-analysis found no evidence of benefit. For nutritional status, both original findings and re-analysis described modest evidence for a small improvement. For school attendance, re-analysis showed benefits similar to those originally found in intervention schools for both children who did and those who did not receive deworming drugs. However, after correction of coding errors, there was little evidence of an indirect effect on school attendance among children in schools close to intervention schools. Combining these effects gave a total increase in attendance of 3.9% among treated children, which was no longer statistically significant. As in the original results, re-analysis found no effect of the intervention on examination performance. CONCLUSIONS: Re-applying analytical approaches originally used, but correcting various errors, we found little evidence for some previously-reported indirect effects of a deworming intervention. Effects on worm infections, nutritional status, examination performance and school attendance on children in intervention schools were largely unchanged

Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a statistical replication of a cluster quasi-randomized stepped-wedge trial.

INTRODUCTION: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits for worm infections and school attendance. METHODS: In this statistical replication, we re-analysed data from this cluster quasi-randomized stepped-wedge trial, specifying two co-primary outcomes: school attendance and examination performance. We estimated intention-to-treat effects using year-stratified cluster-summary analysis and observation-level random-effects regression, and combined both years with a random-effects model accounting for year. The participants were not blinded to allocation status, and other interventions were concurrently conducted in a sub-set of schools. A protocol guiding outcome data collection was not available. RESULTS: Quasi-randomization resulted in three similar groups of 25 schools. There was a substantial amount of missing data. In year-stratified cluster-summary analysis, there was no clear evidence for improvement in either school attendance or examination performance. In year-stratified regression models, there was some evidence of improvement in school attendance [adjusted odds ratios (aOR): year 1: 1.48, 95% confidence interval (CI) 0.88-2.52, P = 0.147; year 2: 1.23, 95% CI 1.01-1.51, P = 0.044], but not examination performance (adjusted differences: year 1: -0.135, 95% CI -0.323-0.054, P = 0.161; year 2: -0.017, 95% CI -0.201-0.166, P = 0.854). When both years were combined, there was strong evidence of an effect on attendance (aOR 1.82, 95% CI 1.74-1.91, P < 0.001), but not examination performance (adjusted difference -0.121, 95% CI -0.293-0.052, P = 0.169). CONCLUSIONS: The evidence supporting an improvement in school attendance differed by analysis method. This, and various other important limitations of the data, caution against over-interpretation of the results. We find that the study provides some evidence, but with high risk of bias, that a school-based drug-treatment and health-education intervention improved school attendance and no evidence of effect on examination performance

Strengthening surveillance systems for Antimicrobial Resistance in Urinary Tract infections in Kenya – Report from Fleming Fund fellowship programme

Background: Urinary Tract Infection (UTI) is one of the most common reasons for outpatient attendance and antibiotic use worldwide. Tackling the problem of antimicrobial resistance (AMR) in Low- and Middle-Income Countries such as Kenya requires laboratory surveillance systems that can correctly identify bacterial pathogens from urine samples and perform antimicrobial susceptibility testing (AST). In Kenya, there are many shortcomings in public-sector microbiology laboratories, including limited professional expertise in the clinical interpretation of urine samples. Methods: This project aimed to deliver training on identification and AST for staff at five hospital laboratories participating in the Kenyan AMR surveillance network. We made local needs assessments, delivered practical training sessions face-to-face and administered written and practical competency assessments for all participants. Results: Trainings were conducted between November 2021 and January 2022 with a total of 13 laboratory staff trained. Participants had previously received a median of 2.3 months (IQR 1-7 months) of training time in microbiology. There was a substantial improvement in written assessment scores from a median of 46/100 pre-training (IQR 36-64) to a median of 90/100 post-training (IQR 85-92). The largest improvements were seen amongst staff with the lowest prior levels of microbiology training (MLS Diploma), though improvements were also seen for staff with BSc and MSc qualifications. Practical assessment included use of standardized organisms – all participants performed well in this practical assessment. Conclusion: We found that prior to the training, all staff performed relatively poorly on a standardized assessment regarding knowledge and processing of urine samples. However, all staff substantially improved following this 5-day training delivered by a single trainer. We estimated that the cost of delivering this training for one hospital was approximately KES 500,000. Training microbiology staff in the accurate processing of urine sample will be an important activity for a Kenyan AMR surveillance system. These training materials, if delivered by an experienced trainer, can achieve a clear improvement in knowledge levels and practical competence