Publications by authors named "Alexander Downie"

Article Synopsis
  • Ankle osteoarthritis (OA) lacks specific management guidelines, and studies typically focus on education, weight loss, and exercise for OA across different body regions.
  • The objective of the study was to assess the feasibility of a randomized controlled trial (RCT) comparing physiotherapist-led education and exercise to general advice for ankle OA management.
  • Results showed high feasibility, with a 97% consent rate, 71% adherence to interventions, 94% intervention fidelity, and 87% completion of follow-up measures, indicating potential for a larger RCT in the future.
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The study of immune phenotypes in wild animals is beset by numerous methodological challenges, with assessment of detailed aspects of phenotype difficult to impossible. This constrains the ability of disease ecologists and ecoimmunologists to describe immune variation and evaluate hypotheses explaining said variation. The development of simple approaches that allow characterization of immune variation across many populations and species would be a significant advance.

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Article Synopsis
  • - The study investigates how genetics and environment together affect immune responses in mice, focusing on three different inbred strains (C57BL/6, 129S1, PWK/PhJ) in an outdoor setting and infected with a specific parasite.
  • - It finds that while the overall structure of immune cells is influenced by both genetics and the environment, the variation in certain immune responses, like cytokine levels, is mainly determined by genetics, affecting how many parasites the mice carry.
  • - Additionally, the expression of immune markers like CD44 shows different influences: on T cells, it’s mostly genetic, while on B cells, it’s more environmental; and importantly, the impact of genetics appears to lessen when the mice
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Environmental influences on immune phenotypes are well-documented, but our understanding of which elements of the environment affect immune systems, and how, remains vague. Behaviors, including socializing with others, are central to an individual's interaction with its environment. We therefore tracked behavior of rewilded laboratory mice of three inbred strains in outdoor enclosures and examined contributions of behavior, including associations measured from spatiotemporal co-occurrences, to immune phenotypes.

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The characterization of a new group of innate pattern recognition receptors detected in >500 species across the tree of life by Li et al. reveals surprising commonalities and peculiarities shared with other innate receptors. Receptor diversity within and among species opens the way to reconsidering the costs and benefits of innate immune recognition.

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The paucity of blood granulocyte populations such as neutrophils in laboratory mice is a notable difference between this model organism and humans, but the cause of this species-specific difference is unclear. We previously demonstrated that laboratory mice released into a seminatural environment, referred to as rewilding, display an increase in blood granulocytes that is associated with expansion of fungi in the gut microbiota. Here, we find that tonic signals from fungal colonization induce sustained granulopoiesis through a mechanism distinct from emergency granulopoiesis, leading to a prolonged expansion of circulating neutrophils that promotes immunity.

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The relative and synergistic contributions of genetics and environment to inter-individual immune response variation remain unclear, despite its implications for understanding both evolutionary biology and medicine. Here, we quantify interactive effects of genotype and environment on immune traits by investigating three inbred mouse strains rewilded in an outdoor enclosure and infected with the parasite, . Whereas cytokine response heterogeneity was primarily driven by genotype, cellular composition heterogeneity was shaped by interactions between genotype and environment.

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Hosts diverge widely in how, and how well, they defend themselves against infection and immunopathology. Why are hosts so heterogeneous? Both epidemiology and life history are commonly hypothesized to influence host immune strategy, but the relationship between immune strategy and each factor has commonly been investigated in isolation. Here, we show that interactions between life history and epidemiology are crucial for determining optimal immune specificity and sensitivity.

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Madagascar's lemurs display a diverse array of feeding strategies with complex relationships to seed dispersal mechanisms in Malagasy plants. Although these relationships have been explored previously on a case-by-case basis, we present here the first comprehensive analysis of lemuriform feeding, to our knowledge, and its hypothesized effects on seed dispersal and the long-term survival of Malagasy plant lineages. We used a molecular phylogenetic framework to examine the mode and tempo of diet evolution, and to quantify the associated morphological space occupied by Madagascar's lemurs, both extinct and extant.

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Background: Madagascar's rain forests are characterized by extreme and uneven patterns of species richness and endemicity, the biogeographic and evolutionary origins of which are poorly understood.

Methods: Here we use a time-calibrated phylogeny of a dominant group of trees in Madagascar's eastern rain forests, Canarium, and related Burseraceae (Canarieae), to test biogeographic hypotheses regarding the origin and radiation of the flora of this unique biome.

Results: Our findings strongly support the monophyly of Malagasy Canarium, suggesting that this clade represents a previously undocumented in situ radiation.

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