Biology subjects

Woolley, T.

Publications and source records attributed to Woolley, T..

3 recordsLinked to original sources

bioRxiv2023

Comparability and Stability of Holotranscobalamin levels in Capillary and Venous Blood

IntroductionSelf-collected capillary blood has numerous advantages over venous samples taken via phlebotomy, as such the use of this finger-prick testing has increased over recent years, driven in some part by Covid antibody testing. However, there is limited evidence that venous and capillary serum is comparable for many routine analytes. In this study we aimed to determine whether capillary sampling could offer an alternative sampling method to venous for the assessment of vitamin B12 in the form of holotranscobalamin, and if this analyte was stable in unspun capillary blood for three days, thus allowing for samples to be returned by the postal system. MethodsMatched pairs of capillary and venous blood samples were collected from 25 patients for the determination of holotranscobalamin, one set being processed on day zero, the other set being stored at ambient temperature and then processed on day three to mimic postal samples. Self-collected capillary blood was compared with phlebotomist-collected venous samples using correlation, Passing-Bablock regression, and Altman-Bland analysis. ResultsPassing-Bablock and Bland-Altman analysis showed holotranscobalamin levels in capillary and venous serum to be comparable and that the analyte was stable in unspun blood for at least three days at ambient temperatures. ConclusionsWe believe this is the first published study to determine if capillary blood sampling is an acceptable alternative to venous sampling for determining holotranscobalamin concentration; our data indicates that there is no significant difference in results from unspun venous and capillary blood stored at room temperature for at least 3 days compared to venous blood tested on the same day of collection.

pathology↗

bioRxiv2019

Parallel control of mechanosensory hair cell orientation by the PCP and Wnt pathways

Cell polarity plays a crucial role during development of vertebrates and invertebrates. Planar Cell Polarity (PCP) is defined as the coordinated polarity of cells within a tissue axis and is essential for processes such as gastrulation, neural tube closure or hearing. Wnt ligands can be instructive or permissive during PCP-dependent processes, and Wnt pathway mutants are often classified as PCP mutants due to the complexity and the similarities between their phenotypes. Our studies of the zebrafish sensory lateral line reveal that disruptions of the PCP and Wnt pathways have differential effects on hair cell orientations. While mutations in PCP genes cause random orientations of hair cells, mutations in Wnt pathway members induce hair cells to adopt a concentric pattern. We show that PCP signaling is normal in hair cells of Wnt pathway mutants and that the concentric hair cell phenotype is due to altered organization of the surrounding support cells. Thus, the PCP and Wnt pathways work in parallel, as separate pathways to establish proper hair cell orientation. Our data suggest that coordinated support cell organization is established during the formation of lateral line primordia, much earlier than the appearance of hair cells. Together, these finding reveal that hair cell orientation defects are not solely explained by defects in PCP signaling and that some hair cell phenotypes warrant reevaluation.

developmental biology↗

bioRxiv2017

Mathematical modelling of cortical neurogenesis reveals that the founder population does not necessarily scale with neuronal output

The mammalian cerebral neocortex has a unique structure, composed of layers of different neuron types, interconnected in a stereotyped fashion. While the overall developmental program seems to be conserved, there are divergent developmental factors generating cortical diversity amongst mammalian species. In terms of cortical neuronal numbers some of the determining factors are the size of the founder population, the duration of cortical neurogenesis, the proportion of different progenitor types, and the fine-tuned balance between self-renewing and differentiative divisions. We develop a mathematical model of neurogenesis that, accounting for these factors, aims at explaining the high diversity in neuronal numbers found across mammalian species. By framing our hypotheses in rigorous mathematical terms, we are able to identify paths of neurogenesis that match experimentally observed patterns in mouse, macaque and human. Additionally, we use our model to identify key parameters that would particularly benefit from accurate experimental investigation. We find that the timing of a switch in favor of symmetric neurogenic divisions produces the highest variation in cortical neuronal numbers. Surprisingly, in our model the increase in cortical neuronal numbers does not necessarily reflect a larger size of founder population, a prediction that identified a specific need for experimental quantifications.

neuroscience↗