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The Effect of Physical Activity during Pregnancy on the Development of Postpartum Depression (PPD): A Literature Review
No full textIntroduction: Postpartum depression (PPD) is a condition characterized by major depressive mood disorder following childbirth. The onset of depressive symptoms is most often within four weeks after childbirth, but the diagnosis is often made up until a year postpartum. Current prevention and treatment strategies focus on the use of psychotherapy and anti-depressant medications. The research on alternative interventions such as the effect of exercise on the prevention of PPD is limited and inconclusive.
Objective: The purpose of this study is to further understand how efficacious exercise is in the prevention of PPD. There are currently very few recommendations for preventing PPD, thus there are knowledge gaps to fill in this area of research. This study will look at the current literature and determine if there is enough evidence to recommend physical activity during pregnancy for the prevention of PPD.
Methods: A literature search was done using PubMed and PsycINFO databases. The search was performed using key terms about physical activity during pregnancy and its relation to the prevention of PPD. Six articles were found that best met the inclusion criteria and were therefore used in the literature review.
Results: Four studies selected were randomized controlled trials (RCTs) which used an intervention to investigate how physical activity would impact depression screening in the postpartum period. The other two articles used prospective and retrospective cohorts to analyze if activity levels would influence EPDS scores in the postpartum period.
Discussion/Conclusion: The studies selected for review differed in study design and therefore the results of each study had some variation. Two of the RCTs showed no significant impact from exercise during pregnancy on PPD. However, these studies both faced issues with adherence, among other limiting factors. The other two RCTs selected followed similar protocols and both found exercise during pregnancy resulted in less prevalence of depressive symptoms in the postpartum period. Furthermore, both observational studies drew similar conclusions regarding the association between individuals reporting higher levels of activity in pregnancy and lower EPDS scores. No studies reviewed reported adverse effects from exercise during pregnancy on maternal mental health. Nonetheless, more research should be completed to validate the effect of prenatal exercise on the prevention of depression in the postpartum period
Methods for chronic disease epidemiology: longitudinal data and case definitions
No full textAdministrative health data, such as physician billing claims and hospital discharge abstracts, are routinely used to produce chronic disease estimates (i.e., incidence and prevalence). Incidence and prevalence measures are estimated using case definitions, a set of rules for identifying disease cases, including disease-specific diagnosis codes. Creating valid case definitions can be challenging due to errors in diagnosis codes and changes in their use and meaning over time. Using multiple years of data that capture an individual’s longitudinal health history may be advantageous for constructing accurate case definitions. The goal of this research was to develop and evaluate chronic disease case definitions using longitudinal administrative health data. Four related studies were conducted.
The first study assessed case definition sensitivity to changes in data quality using control charts, which were originally developed to monitor out-of-control processes in manufacturing. Control charts were applied to juvenile diabetes (JD) incidence and prevalence trends that were estimated using previously validated case definitions. Frequency of out-of-control observations, which may be influenced by nonrandom errors in data, was compared across case definitions using McNamar’s test with a Holm-Bonferroni adjustment and control limits based on Cohen’s effect size. No differences in incidence and prevalence trends were detected.
The second study applied control charts to multiple sclerosis (MS) incidence and prevalence trends to determine if control limit calculations to identify out-of-control observations could be generalized across diseases. Similar to JD, there were no differences in incidence and prevalence trends across case definitions. However, results indicated wider control limits may be more appropriate for MS compared to JD.
The third study developed and evaluated the performance of model-based case definitions for MS that relied on trends in healthcare use to identify cases. Dynamic classification, which ascertains cases and non-cases annually, was used to estimate the average trend needed for case classification. A trend-based case definition resulted in similar estimates of validity compared to a deterministic case definition of three or more MS contacts; an observation period of unlimited duration was used to ascertain cases. However, the trend-based case definition had higher sensitivity than the deterministic case definition when the number of data years used for classification was reduced to five years, which was the estimated average trend needed.
In the fourth study, I created and validated MS and JD model-based case definitions that incorporated a reclassification exit rule to account for biased prevalence trends due to misclassification. Case probabilities were calculated annually and used to reclassify individuals when the probabilities dropped below a cut-off criterion. Comparisons of prevalence trends obtained from the exit rule case definition to trends obtained from existing national case definitions revealed differences in slope trends for MS, but not for JD.
This research contributes to the literature on use of administrative health data for health research and surveillance. It demonstrates the importance of considering how changes over time in data-, disease-, and case definition-based factors can be incorporated into chronic disease case definition development and application. Findings are beneficial to epidemiologists and researchers who rely on the Public Health Agency of Canada’s Canadian Chronic Disease Surveillance System to routinely and systematically monitor population health using administrative health data.Visual and Automated Data Analytics Graduate Training ProgramOctober 202
Wettability of saliva substitutes on CAD/CAM denture base materials
No full textPurpose: To measure and compare contact angle (CA) goniometry of liquids on denture bases manufactured by different methods, and to investigate the impact of physical and chemical topography, as well as various saliva substitutes, on contact angle measurements.
Methods: This study was organized into three phases. Phase 1 measured contact angle (CA) of deionized water on two non-polished CAD/CAM denture bases: Mnp (milled; Lucitone 199 disc milled in Dentsply MCX5) and Pnp (printed; Formlabs denture base resin printed in Formlabs 3B). Phase 2 measured CA of deionized water on 5 polished denture bases: C (conventional; Lucitone 199 heat cured), M (milled), P (printed), I (injection molded; Ivocap), and F (flexible; Ultraflex). Phase 3 measured CA of 5 saliva substitutes – Biotene, VEGA, Spry, Moi-Stir, and Dentilube – on the 5 polished denture bases. Ten droplet measurements were obtained for each group, with each droplet analyzed for static CA, advancing contact angle (ACA), receding contact angle (RCA), and contact angle hysteresis (CAH). Statistical analysis was conducted using ANOVA, with a significance level set at 0.05.
Results: The Pnp exhibited the highest ACA with statistical significance, while the Pnp, Mnp, and I had the lowest RCA. CAH was demonstrated to have statistically significant differences among the denture bases, with Pnp exhibiting the largest CAH, followed by Mnp, and then the polished denture bases. There were no significant differences in CAH among the polished denture bases. The saliva substitutes exhibited differences in ACA, with Spry and VEGA having the highest ACA, while Biotene had the lowest.
Conclusion: The manufacturing methods of denture bases influences the CAH, while the chemical composition of the denture base specimens does not appear to affect CAH. Saliva substitutes do, however, impact CA measurements.October 202
Application of MRI and electrovestibulography on Alzheimer's disease: diagnosis, monitoring and predicting response to treatment
No full textAlzheimer's disease (AD) is a neurodegenerative disorder characterized by gradual loss of memory and cognition. Diagnosing people with pure AD from those subjects who have mixed conditions of AD and cerebrovascular disease (AD-CVD) is a challenging research problem. Another interesting research problem is the monitoring of changes in the comorbid depression of participants with AD when repetitive transcranial magnetic stimulation (rTMS) is applied to improve their cognition. Furthermore, the rTMS has a demanding treatment protocol, and its efficacy for AD is uncertain; a method capable of predicting rTMS responses at baseline would be of great interest. In this thesis, we separately utilized magnetic resonance imaging (MRI) and electrovestibulography (EVestG) to address the above research questions; in particular, using MRI analysis investigating plausible differences between AD and AD-CVD, using EVestG investigating the impact of rTMS on depression comorbidity amongst individuals with AD who received rTMS treatment, and also using MRI analysis predicting patients’ response to rTMS treatment at baseline.
This thesis consists of four studies. Firstly, we conducted voxel-based morphometry on brain MRI data of participants with AD and AD-CVD and controls. In addition to significantly lower gray matter or white matter volumes of AD and AD-CVD compared to controls, a potential differential trend was shown in MRI between AD and AD-CVD. Secondly, we calculated the EVestG-driven depression features of participants with AD and investigated whether their changes were associated with cognition change following rTMS treatment. The EVestG results showed that cognitive improvement following rTMS treatment was not likely due to the improvement in their depression status. Thirdly, significant features from the gray matter of the dorsolateral prefrontal cortex were found, resulting in only 69% accuracy in predicting rTMS efficacy. Fourthly, the MRI-driven histogram-based radiomic features were extracted, and the significant features of rTMS efficacy were selected in a data-driven manner, which resulted in 81.9% accuracy in classifying responders and non-responders to active rTMS. Overall, the studies presented here would provide a way of differentiating AD and AD-CVD, monitoring the quantitative status of depression in AD subjects undergoing rTMS treatment, and aiding in designing personalized treatment techniques for future AD participants.February 202
Low-frequency uniaxial stress reversal fatigue behavior of plain concrete
No full textThis thesis investigates the uniaxial stress reversal fatigue behavior of plain concrete under low-frequency cyclic loading, with a focus on frequencies below 1 Hz. The research aims to enhance the understanding of the fatigue life of concrete structures, particularly in infrastructure subjected to repeated loading such as dams and bridges. The specimens were tested at three specific frequencies: 0.2 Hz, 0.5 Hz, and 0.75 Hz. These tests were performed under a constant stress range of 11.4 MPa, replicating the stress conditions identified through Finite Element Analysis of a spillway from an existing gravity dam in northern Manitoba. The testing regime set the maximum stress level at 90% of the tensile strength of the concrete and the minimum stress level at 20% of the compressive strength of the concrete.
The analysis concentrated on evaluating the fatigue life of concrete, examining maximum strain curves, stiffness degradation, and energy dissipation under stress reversal conditions. The analysis revealed that higher frequencies generally resulted in a longer fatigue life. The maximum strain and stiffness degradation curves exhibited typical S-shaped patterns, indicating progressive damage accumulation in the concrete specimens, and increasing strain at failure. Additionally, stiffness degradation showed negligible differences in deterioration indices between 0.5 Hz and 0.75 Hz, with slightly higher deterioration observed at 0.2 Hz. Energy analysis indicated that higher frequencies result in increased energy dissipation per fatigue cycle.
The application of the Weibull distribution effectively modeled the variability in fatigue life data, providing insights into the probabilistic nature of concrete's fatigue behavior under stress reversal loading. Furthermore, the research included a validation of the stress reversal fatigue model proposed by Ferreira et al. (2024). The model's applicability across different frequencies was assessed, demonstrating its potential for broader application in predicting the fatigue behavior of concrete under uniaxial stress reversal loading.February 202
A scoping review of early childhood caries, poverty and the first sustainable development goal
Get PDFBackground
Poverty is a well-known risk factor for poor health. This scoping review (ScR) mapped research linking early childhood caries (ECC) and poverty using the targets and indicators of the Sustainable Development Goal 1 (SDG1).
Methods
We searched PubMed, Web of Science, and Scopus in December 2023 using search terms derived from SDG1. Studies were included if they addressed clinically assessed or reported ECC, used indicators of monetary or multidimensional poverty or both, and were published in English with no date restriction. We excluded books and studies where data of children under 6 years of age could not be extracted. We charted the publication year, study location (categorized into income levels and continents), children age, sample size, study design, measures of ECC, types and levels of poverty indicators and adjusted analysis. The publications were also classified based on how the relation between poverty and ECC was conceptualized.
Results
In total, 193 publications were included with 3.4 million children. The studies were published from 1989 to 2023. Europe and North America produced the highest number of publications, predominantly from the UK and the US, respectively. Age-wise, 3–5-year-olds were the most studied (62.2%). Primary studies (83.9%) were the majority, primarily of cross-sectional design (69.8%). Non-primary studies (16.1%) included reviews and systematic reviews. ECC was mainly measured using the dmf indices (79.3%), while poverty indicators varied, with the most common used indicator being income (46.1%). Most studies measured poverty at family (48.7%) and individual (30.1%) levels. The greatest percentage of publications addressed poverty as an exposure or confounder (53.4%), with some studies using poverty to describe groups (11.9%) or report policies or programs addressing ECC in disadvantaged communities (11.4%). In addition, 24.1% of studies requiring adjusted analysis lacked it. Only 13% of publications aligned with SDG1 indicators and targets.
Conclusion
The ScR highlight the need for studies to use indicators that provide a comprehensive understanding of poverty and thoroughly examine the social, political, and economic determinants and impact of ECC. More studies in low and middle-income countries and country-level studies may help design interventions that are setting- and economic context-relevant
The wildflower garden: ecological restoration in urban environments
Get PDFClimate change, unrestricted urban sprawl, and industrial agriculture have led to catastrophic degradation of native habitats and unprecedented biodiversity loss, especially within cities. To help address this, this practicum highlights the use of native wildflower and grass species in urban environments as alternatives to traditional turf grass landscaping. Through small-scale wildflower garden design and implementation, and community engagement, approximately 120 square feet of lawn was converted to host 14 native plant species with 168 individual plants. A community-based presentation was delivered to inspire like-minded individuals into restoring parts of their own spaces with native species in hopes of creating a mosaic or habitat matrix within a local urban environment. After speaking with city planning officials and community organizations, the general consensus is that people are in favour of habitat restoration but the problem of long-term maintenance and funding remains prevalent. By working with enthusiastic homeowners, these challenges can be addressed and sustainable care and stewardship may be achieved.October 202
Thermostability of lyophilized VSV-based vaccines
No full textLyophilization maximises vaccines’ stability, shelf life; maintains chemical or biological functions; enables easier transportation and storage compared to a cold chain. Success of vesicular stomatitis virus (VSV) based vaccines has been highlighted by its increased adoption by pharmaceutical companies and most importantly, the recently approved vaccine for high consequence Ebola virus (EBOV). Lujo virus (LUJV) and Lassa virus (LASV), both arenaviruses, are still without licensed vaccines, however, researchers are exploring VSV-vectored vaccines. Many of these highly pathogenic viruses are endemic in tropical regions like Africa where slight breach in cold chain may affect stability of vaccines. It was established that slight changes in cold chain conditions do not affect efficacy of VSV-based vaccines, however, it is imperative to optimise thermostability of VSV-based vaccines using lyophilization. The primary hypothesis of this study is that lyophilized VSV-LASV and VSV-EBOV vaccines exposed to sub-optimal temperature will retain infectivity in cell culture and protect against LASV challenge in inbred Hartley guinea pigs. Different combinations of commercially available stabilisers were used to assess the thermostability of VSV-based vaccines at 4, 21 and 37 °C of storage temperatures. Lyophilized VSV-LASV and VSV-EBOV were recoverable in Vero cells, the recovery titer showed an inverse relationship with exposed temperature and duration of storage of 1, 7, 35 and 90 days. Furthermore, lyophilized VSV-LASV affords 100% protection and sterilising immunity against LASV infection in inbred Hartley guinea pigs.May 202
Role of the thioredoxin system in chronic corticosterone treatment- impaired neuronal differentiation and degeneration
No full textDuring the stress response, the hypothalamic-pituitary-adrenal (HPA) axis releases glucocorticoids into the bloodstream, targeting different organs including the brain. Chronic stress is a major risk factor for depression. Thioredoxin (Trx) is an oxidoreductase that reverses protein cysteine thiol oxidation, inhibits apoptosis signal-regulating kinase 1 (ASK1) and has been shown to promote cAMP response element-binding protein (CREB) activation. Trx reductase (TrxR) maintains Trx in a reduced state, while Trx interacting protein (Txnip) acts as an endogenous Trx inhibitor. Studies from our lab showed that chronic stress and chronic corticosterone (CORT) treatment upregulated Txnip and induced oxidative damage in cultured mouse neurons and mouse brain, suggesting that Trx system mediates CORT-induced neuronal damage. The objective of this work is to investigate the role of Trx system in chronic CORT-impaired neuronal differentiation and CORT-enhanced neurodegeneration. First, we found that Trx and TrxR protein levels increased during differentiation, while Txnip increased during neurodegeneration of primary mouse cortical neurons. Blocking Trx with CRISPR/Cas9 or the Trx inhibitor PX12 reduced neurite outgrowth. PX12 treatment also reduced the expression of synaptic proteins vGLUT1 and PSD95. Second, we found that CREB phosphorylation increased during neuronal differentiation and that blocking Trx reduced CREB phosphorylation in primary cortical neurons. In SH-SY5Y cells, we found that H2O2 reduced CREB phosphorylation and promoted CREB cysteine oxidation, while treatment with Trx mimetic peptide CB3 reversed H2O2 effect. We also found in primary mouse cortical neurons that ASK1 phosphorylation was increased during neurodegeneration and that PX12 increased ASK1 phosphorylation. Third, we found that CORT treatment elevated Txnip protein levels, reduced CREB phosphorylation, enhanced ASK1 phosphorylation, and impaired neurite outgrowth in primary neurons. Knocking down Txnip prevented CORT-impaired neurite outgrowth. Fourth, we found that chronic CORT injections induced depressive-like behaviors in mice, which was reversed by knocking down Txnip in the frontal cortex. Our findings suggest that Trx can facilitate neuronal differentiation by preserving the cellular redox balance, inhibiting CREB cysteine oxidation and maintaining CREB activation. Trx can also inhibit ASK1 apoptotic signaling and produce a neuroprotective effect. Chronic CORT treatment can upregulate Txnip, which may further inhibit Trx activity, inhibiting neurite outgrowth and promoting depressive-like behaviors in mice.October 202
Examining how changes in consumption patterns of specific dietary fibre subtypes are associated with disease development, progression, and outcomes in autoimmune diseases of the gut-brain axis impacted by an altered gut microbiome
No full textDietary fibres are typically fermented by gut microbes, producing beneficial short-chain fatty acids (SCFAs). In chronic diseases like inflammatory bowel disease (IBD), studies show reduced fibre-fermenting microbiota and SCFAs, alongside worsened symptoms from high-fibre diets, suggesting impaired fibre fermentation may worsen disease outcomes. Our team previously found that select unfermented fibres (e.g., β-fructans) induce gut inflammation and damage in IBD, which was linked to decreased β-fructan consumption. We believe this decrease is a subconscious avoidance of foods associated with worsened symptoms, supporting possible connections between microbiota-driven fibre fermentation and gut-brain axis (GBA) physiology. This further suggests that unfermented fibres' impacts may not be isolated to gut diseases but extend to the nervous system. Given that multiple sclerosis (MS) also shows reduced fibre-fermenting microbiota and SCFA, altered immune pathways, and worsened symptoms on high-fibre diets, I hypothesized that reduced consumption of specific dietary fibres in autoimmune GBA conditions links to lower fibre-fermenting microbiota and worsened symptoms in IBD (gut) and MS (brain).
I aimed to: 1) validate our method for examining fibre subtype consumption patterns, 2) assess fibre consumption's association with IBD development and progression, 3) analyze fibre consumption in MS patients, and 4) examine the link between unfermented fibres and CNS damage in experimental autoimmune encephalomyelitis (EAE) mice.
I found β-fructan fibre consumption significantly decreased before IBD development (n=3,400) compared to healthy controls, and again during IBD progression from remission to flare (n=155) compared to those in remission. Diet was assessed using a validated food frequency questionnaire (FFQ), with results linked to microbial metabolites. MS patients also consumed significantly less β-fructan than healthy controls. Germ-free EAE MS mice displayed increased spinal demyelination and inflammatory markers in the gut and spine. My findings, described in my thesis, suggest that reduced β-fructan consumption in autoimmune GBA diseases may stem from learned avoidance due to symptoms from reduced β-fructan fermentation. Further research is needed to translate findings clinically for precision nutrition strategies in these diseases.February 202