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Biology subjects

Wiens, M.

Publications and source records attributed to Wiens, M..

2 recordsLinked to original sources

Resource: Scalable whole genome sequencing of 40,000 single cells identifies stochastic aneuploidies, genome replication states and clonal repertoires

Essential features of cancer tissue cellular heterogeneity such as negatively selected genome topologies, sub-clonal mutation patterns and genome replication states can only effectively be studied by sequencing single-cell genomes at scale and high fidelity. Using an amplification-free single-cell genome sequencing approach implemented on commodity hardware (DLP+) coupled with a cloud-based computational platform, we define a resource of 40,000 single-cell genomes characterized by their genome states, across a wide range of tissue types and conditions. We show that shallow sequencing across thousands of genomes permits reconstruction of clonal genomes to single nucleotide resolution through aggregation analysis of cells sharing higher order genome structure. From large-scale population analysis over thousands of cells, we identify rare cells exhibiting mitotic mis-segregation of whole chromosomes. We observe that tissue derived scWGS libraries exhibit lower rates of whole chromosome anueploidy than cell lines, and loss of p53 results in a shift in event type, but not overall prevalence in breast epithelium. Finally, we demonstrate that the replication states of genomes can be identified, allowing the number and proportion of replicating cells, as well as the chromosomal pattern of replication to be unambiguously identified in single-cell genome sequencing experiments. The combined annotated resource and approach provide a re-implementable large scale platform for studying lineages and tissue heterogeneity.

genomics

The saturation gap: a simple transformation of oxygen saturation using virtual shunt

ObjectivePeripheral oxygen saturation (SpO2) obtained from pulse oximetry is a widely used physiological measurement. Clinical interpretation is limited by the nonlinear relationship between SpO2, degree of impairment in gas exchange, and effect of altitude. SpO2 is frequently dichotomized to overcome these limitations during prediction modelling. Using the known physiological relationship between virtual shunt and SpO2, we propose the saturation gap as a transformation of SpO2.\n\nApproachWe computed the theoretical virtual shunt corresponding to various SpO2 values and derived an accurate approximation formula between virtual shunt and SpO2. The approximation was based on previously described empiric observations and known physiological relationships. We evaluated the utility of the saturation gap in a clinical study predicting the need for facility admission in children in a rural health-care setting.\n\nMain ResultsThe transformation was saturation gap = 49.314*log10(103.711 - SpO2) -37.315. The ability to predict hospital admission based on a continuous variable SpO2 or saturation gap produced an identical area under the curve of 0.71 (95% CI: 0.69-0.73), compared to only 0.57 (CI: 0.56-0.58) based on diagnosis of hypoxemia (defined as SpO2<90%). However, SpO2 demonstrated a lack of fit compared to saturation gap (goodness-of-fit test p-value <0.0001 versus 0.098). The observed admission rates varied linearly with saturation gap but varied nonlinearly with SpO2.\n\nSignificanceThe saturation gap estimates a continuous linearly interpretable disease severity from SpO2 and improves clinical prediction models. The saturation gap will also allow for straightforward incorporation of altitude in interpretation of measurements of SpO2.

bioengineering