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1.
Contemp Clin Trials Commun ; 33: 101154, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37250507

RESUMEN

Background: Breast cancer survivors (BCS) with overweight or obesity are at heightened risk of cancer recurrence, cardiometabolic disease, and compromised quality of life. Given the prevalence of significant weight gain during and following breast cancer treatment, there is growing recognition of the need to develop efficacious, widely-accessible, weight management programs for BCS. Unfortunately, access to evidence-based weight management resources for BCS remains limited and little is known of the optimal theoretical basis, program components, and mode of delivery for community-based interventions. The primary aim of the Healthy New Albany Breast Cancer (HNABC) pilot trial was to determine the safety, feasibility, and preliminary efficacy of delivering a translational, evidence-based, and theory-driven lifestyle weight management intervention to BCS with overweight or obesity in the community setting. Methods: HNABC was a single-arm, pilot trial evaluating a 24-week, multi-component intervention leveraging exercise, dietary modification, and group-mediated cognitive behavioral (GMCB) counseling components designed to facilitate lifestyle behavior change and promote sustained independent adherence. Assessments of various objectively-determined and patient-reported outcomes and theory-derived determinants of behavioral adoption and maintenance were obtained at baseline, 3- and 6-month follow-up. Measures of trial feasibility were calculated prospectively throughout the study. Conclusion: Findings from the HNABC pilot trial will provide evidence demonstrating the feasibility and preliminary efficacy of a multi-component, community-based, GMCB lifestyle weight management intervention for BCS. Results will inform the design of a future, large-scale, randomized controlled efficacy trial. If successful, this approach could offer a widely accessible, community-based intervention model for weight management programs in BCS.

2.
Contemp Clin Trials ; 115: 106730, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35283261

RESUMEN

Being overweight or obese is a primary modifiable risk factor that exacerbates disease progression and mobility disability in older knee osteoarthritis (OA) patients. Lifestyle interventions combining exercise with dietary weight loss (EX+DWL) yield meaningful improvements in mobility and weight loss that are superior to EX or DWL alone. Unfortunately, community access to practical, sustainable weight management interventions remains limited and places knee OA patients at increased risk of mobility disability. The Collaborative Lifestyle Intervention Program in Knee Osteoarthritis patients (CLIP-OA), was a two-arm, 18 month randomized-controlled, comparative effectiveness trial designed to contrast the effects of an evidence-based, theory-driven EX+DWL intervention, personalized to patient needs and delivered by our community partners, with those of the Arthritis Foundation's Walk With Ease (WWE) standard of care self-management program in the treatment of knee OA patients with overweight or obesity. The primary outcome of the CLIP-OA trial was mobility performance assessed using the 400-m walk test (400MWT). Secondary outcomes included weight loss, pain, select quality of life and social cognitive variables, and cost-effectiveness of intervention delivery. Findings from the CLIP-OA trial will determine the comparative and cost-effectiveness of the EX+DWL and WWE interventions on key clinical outcomes and has the potential to offer a sustainable medium for intervention delivery that can promote widely accessible weight management among knee OA patients with overweight or obesity. Trial Registration: NCT02835326.


Asunto(s)
Osteoartritis de la Rodilla , Anciano , Terapia por Ejercicio , Humanos , Estilo de Vida , Obesidad/complicaciones , Obesidad/terapia , Osteoartritis de la Rodilla/complicaciones , Osteoartritis de la Rodilla/terapia , Sobrepeso/complicaciones , Sobrepeso/terapia , Calidad de Vida , Resultado del Tratamiento , Pérdida de Peso
3.
Elife ; 112022 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-35188101

RESUMEN

The prevalence of multicellular organisms is due in part to their ability to form complex structures. How cells pack in these structures is a fundamental biophysical issue, underlying their functional properties. However, much remains unknown about how cell packing geometries arise, and how they are affected by random noise during growth - especially absent developmental programs. Here, we quantify the statistics of cellular neighborhoods of two different multicellular eukaryotes: lab-evolved 'snowflake' yeast and the green alga Volvox carteri. We find that despite large differences in cellular organization, the free space associated with individual cells in both organisms closely fits a modified gamma distribution, consistent with maximum entropy predictions originally developed for granular materials. This 'entropic' cellular packing ensures a degree of predictability despite noise, facilitating parent-offspring fidelity even in the absence of developmental regulation. Together with simulations of diverse growth morphologies, these results suggest that gamma-distributed cell neighborhood sizes are a general feature of multicellularity, arising from conserved statistics of cellular packing.


Asunto(s)
Evolución Molecular Dirigida , Volvox/genética , Levaduras/genética , Tamaño de la Célula , Filogenia , Volvox/citología , Volvox/fisiología , Levaduras/citología , Levaduras/fisiología
4.
Phytochemistry ; 187: 112710, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33930670

RESUMEN

Three putative 21-hydroxypregnane 21-O-malonyltransferases (21MaT) from Digitalis lanata were partially purified. Two of them were supposed to be BAHD-type enzymes. We were unable to purify them in quantities necessary for reliable sequencing. We identified two genes in A. thaliana coding for substrate-promiscuous BAHD-type phenolic glucoside malonyltransferases (AtPMaT1, AtPMaT2) and docked various 21-hydroxypregnanes into the substrate-binding site of a homology model built on the BAHD template 2XR7 (NtMaT1 from N. tabacum). Recombinant forms of Atpmat1 and Atpmat2 were expressed in E. coli and the recombinant enzymes characterized with regard to their substrate preferences. They were shown to malonylate various 21-hydroxypregnanes. The Atpmat1 sequence was used to identify candidate genes in Digitalis lanata (Dlmat1 to Dlmat4). Dlmat1 and Dlmat2 were also expressed in E. coli and shown to possess 21-hydroxypregnane 21-O-malonyltransferase activity.


Asunto(s)
Arabidopsis , Digitalis , Arabidopsis/genética , Cardenólidos , Escherichia coli/genética , Glucósidos
5.
PLoS Biol ; 16(7): e2005536, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-30001335

RESUMEN

Variability is emerging as an integral part of development. It is therefore imperative to ask how to access the information contained in this variability. Yet most studies of development average their observations and, discarding the variability, seek to derive models, biological or physical, that explain these average observations. Here, we analyse this variability in a study of cell sheet folding in the green alga Volvox, whose spherical embryos turn themselves inside out in a process sharing invagination, expansion, involution, and peeling of a cell sheet with animal models of morphogenesis. We generalise our earlier, qualitative model of the initial stages of inversion by combining ideas from morphoelasticity and shell theory. Together with three-dimensional visualisations of inversion using light sheet microscopy, this yields a detailed, quantitative model of the entire inversion process. With this model, we show how the variability of inversion reveals that two separate, temporally uncoupled processes drive the initial invagination and subsequent expansion of the cell sheet. This implies a prototypical transition towards higher developmental complexity in the volvocine algae and provides proof of principle of analysing morphogenesis based on its variability.


Asunto(s)
División Celular , Morfogénesis , Volvox/citología , Volvox/crecimiento & desarrollo , Forma de la Célula , Elasticidad , Modelos Biológicos
6.
BMC Dev Biol ; 16(1): 35, 2016 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-27733125

RESUMEN

BACKGROUND: The multicellular volvocine alga Pleodorina is intermediate in organismal complexity between its unicellular relative, Chlamydomonas, and its multicellular relative, Volvox, which shows complete division of labor between different cell types. The volvocine green microalgae form a group of genera closely related to the genus Volvox within the order Volvocales (Chlorophyta). Embryos of multicellular volvocine algae consist of a cellular monolayer that, depending on the species, is either bowl-shaped or comprises a sphere. During embryogenesis, multicellular volvocine embryos turn their cellular monolayer right-side out to expose their flagella. This process is called 'inversion' and serves as simple model for epithelial folding in metazoa. While the development of spherical Volvox embryos has been the subject of detailed studies, the inversion process of bowl-shaped embryos is less well understood. Therefore, it has been unclear how the inversion of a sphere might have evolved from less complicated processes. RESULTS: In this study we characterized the inversion of initially bowl-shaped embryos of the 64- to 128-celled volvocine species Pleodorina californica. We focused on the movement patterns of the cell sheet, cell shape changes and changes in the localization of cytoplasmic bridges (CBs) connecting the cells. The development of living embryos was recorded using time-lapse light microscopy. Moreover, fixed and sectioned embryos throughout inversion and at successive stages of development were analyzed by light and transmission electron microscopy. We generated three-dimensional models of the identified cell shapes including the localization of CBs. CONCLUSIONS: In contrast to descriptions concerning volvocine embryos with lower cell numbers, the embryonic cells of P. californica undergo non-simultaneous and non-uniform cell shape changes. In P. californica, cell wedging in combination with a relocation of the CBs to the basal cell tips explains the curling of the cell sheet during inversion. In volvocine genera with lower organismal complexity, the cell shape changes and relocation of CBs are less pronounced in comparison to P. californica, while they are more pronounced in all members of the genus Volvox. This finding supports an increasing significance of the temporal and spatial regulation of cell shape changes and CB relocations with both increasing cell number and organismal complexity during evolution of differentiated multicellularity.


Asunto(s)
Chlorophyta/citología , Chlorophyta/embriología , Modelos Biológicos , Morfogénesis , Evolución Biológica , División Celular , Chlorophyta/ultraestructura , Microscopía Electrónica de Transmisión , Fotogrametría , Factores de Tiempo
7.
Phys Rev Lett ; 114(17): 178101, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25978266

RESUMEN

Deformations of cell sheets are ubiquitous in early animal development, often arising from a complex and poorly understood interplay of cell shape changes, division, and migration. Here, we explore perhaps the simplest example of cell sheet folding: the "inversion" process of the algal genus Volvox, during which spherical embryos turn themselves inside out through a process hypothesized to arise from cell shape changes alone. We use light sheet microscopy to obtain the first three-dimensional visualizations of inversion in vivo, and develop the first theory of this process, in which cell shape changes appear as local variations of intrinsic curvature, contraction and stretching of an elastic shell. Our results support a scenario in which these active processes function in a defined spatiotemporal manner to enable inversion.


Asunto(s)
Modelos Biológicos , Semillas/crecimiento & desarrollo , Volvox/fisiología , Semillas/citología , Volvox/citología
8.
BMC Biol ; 9: 89, 2011 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-22206406

RESUMEN

BACKGROUND: Epithelial folding is a common morphogenetic process during the development of multicellular organisms. In metazoans, the biological and biomechanical processes that underlie such three-dimensional (3D) developmental events are usually complex and difficult to investigate. Spheroidal green algae of the genus Volvox are uniquely suited as model systems for studying the basic principles of epithelial folding. Volvox embryos begin life inside out and then must turn their spherical cell monolayer outside in to achieve their adult configuration; this process is called 'inversion.' There are two fundamentally different sequences of inversion processes in Volvocaceae: type A and type B. Type A inversion is well studied, but not much is known about type B inversion. How does the embryo of a typical type B inverter, V. globator, turn itself inside out? RESULTS: In this study, we investigated the type B inversion of V. globator embryos and focused on the major movement patterns of the cellular monolayer, cell shape changes and changes in the localization of cytoplasmic bridges (CBs) connecting the cells. Isolated intact, sectioned and fragmented embryos were analyzed throughout the inversion process using light microscopy, confocal laser scanning microscopy, scanning electron microscopy and transmission electron microscopy techniques. We generated 3D models of the identified cell shapes, including the localizations of CBs. We show how concerted cell-shape changes and concerted changes in the position of cells relative to the CB system cause cell layer movements and turn the spherical cell monolayer inside out. The type B inversion of V. globator is compared to the type A inversion in V. carteri. CONCLUSIONS: Concerted, spatially and temporally coordinated changes in cellular shapes in conjunction with concerted migration of cells relative to the CB system are the causes of type B inversion in V. globator. Despite significant similarities between type A and type B inverters, differences exist in almost all details of the inversion process, suggesting analogous inversion processes that arose through parallel evolution. Based on our results and due to the cellular biomechanical implications of the involved tensile and compressive forces, we developed a global mechanistic scenario that predicts epithelial folding during embryonic inversion in V. globator.


Asunto(s)
Células Epiteliales/citología , Morfogénesis , Volvox/citología , Actinas/metabolismo , División Celular , Movimiento Celular , Núcleo Celular , Células Epiteliales/ultraestructura , Microscopía Electrónica de Rastreo , Volvox/crecimiento & desarrollo , Volvox/ultraestructura
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