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McMahon, R.

Publications and source records attributed to McMahon, R..

5 recordsLinked to original sources

Assessment of a high-throughput mass spectrometry method to accelerate biomarker discovery in clinical cancer cohorts using volumetric absorptive microsampling (VAMS) devices.

Identification of biomarkers of early-stage disease typically requires analysis of very large cohorts which can only be reasonably achieved using high-throughput methods. We have developed and optimised novel methods for whole blood analysis using volumetric absorptive microsampling devices to produce over 3000 protein identifications by LCMS on a Q Exactive HF-X Orbitrap. These methods were tested using a set of whole blood samples from lung cancer patients and matching healthy controls finding 455 differentially expressed proteins, using a mid-throughput method enabling analysis of 18 samples per day. To increase throughput for larger clinical cohorts, a 60-sample per day method was tested on a Sciex ZenoTOF 7600. The high-throughput method produced 1.5-fold fewer protein identifications and a higher overall % CV compared to the mid-throughput method. Despite the lower numbers, it produced a set of 36 disease-relevant and discriminatory differentially expressed proteins that, using a machine learning model, could differentiate between the disease and control samples with an area under the ROC curve (AUC) of 88.9% using random forest algorithms. These data support the use of high-throughput mass spectrometry methods to screen large cohorts for diagnostic biomarkers that can then be followed up with more targeted analyses.

biochemistry↗

Investigating the use of novel blood processing methods to boost the identification of biomarkers of non-small cell lung cancer

1.Background and objectivesDiagnosis of non-small cell lung cancer (NSCLC) currently relies on imaging and in-clinic visits, however these methods are not effective at detecting early-stage disease. The investigation into blood-based biomarkers aims to simplify the diagnostic process and has the potential for identifying disease-associated changes before they can be seen using imaging techniques. Methods and designIn this study, plasma and frozen whole blood cell pellets from patients with NSCLC and healthy controls were processed using both classical as well as novel techniques to produce a unique set of 4 sample types from a single blood draw. Samples were analysed using 12 commercially available immunoassay kits in addition to liquid chromatography mass spectrometry using a Q Exactive HF-X Orbitrap to collectively screen 3974 proteins as potential biomarkers. Results and conclusionsAnalysis of all sample types produced a set of 522 differentially expressed proteins, with conventional blood analysis (proteomic analysis of plasma) accounting for only 7 of that total. Boosted regression tree analysis of the differentially expressed proteins produced a panel of 13 proteins that were able to discriminate between controls and NSCLC patients with an area under the ROC curve (AUC) of 0.864 for the set. Our rapid and reproducible blood preparation and analysis methods enable the production of high-quality data from small aliquots of complex samples that are typically seen as requiring significant fractionation prior to proteomic analysis.

cancer biology↗

Characterization of the mesendoderm progenitors in the gastrulating mouse embryo

A population of putative mesendoderm progenitor cells that can contribute cellular descendants to both mesoderm and endoderm lineages is identified. These progenitor cells are localized to the anterior primitive streak and the adjacent epiblast of E7.0-E7.5 mid-to late-gastrula stage embryos. Lineage tracing in vivo revealed that putative mesendoderm progenitors that are marked by Mixl1 and Mesp1 activity contribute descendants to the endoderm layer. Analysis of the role of Mixl1 transcription factor in endoderm differentiation of the mouse epiblast stem cells revealed the choice for endoderm or mesoderm cell fate depends on the timing of activation of Mixl1 upon exit from pluripotency, suggesting Mixl1 function may underpin the divergence of the mesendoderm progenitor to mesoderm and endoderm lineages. The knowledge gained on the spatial, temporal, and lineage attribute of mesendoderm progenitors enriches our mechanistic understanding of germ layer allocation and endoderm differentiation of mesendoderm progenitor in embryonic development and lineage allocation of primed state pluripotent stem cells in vitro.

developmental biology↗

Detection of clade 2.3.4.4b highly pathogenic H5N1 influenza virus in New York City

Highly pathogenic avian influenza viruses of the H5N1 clade 2.3.4.4b arrived in North America in the winter of 2021/2022. These viruses have spread across the Americas causing morbidity and mortality in both wild and domestic birds as well as some mammalian species, including cattle. Many surveillance programs in wildlife as well as commercial poultry operations have detected these viruses. Here we conducted surveillance of avian species in the urban environment in New York City. We detected highly pathogenic H5N1 viruses in six samples from four different bird species and performed full genome sequencing. Sequence analysis showed the presence of multiple different genotypes. Our work highlights that the interface between animals and humans that may give rise to zoonotic infections or even pandemics is not limited to rural environments and commercial poultry operations but extends into the heart of our urban centers. ImportanceWhile surveillance for avian influenza viruses is often focused on migratory routes and their associated stop-over locations, or commercial poultry operations, many bird species - including migratory birds - frequent or live in urban green spaces and wetlands. This brings them into contact with a highly dense population of humans and pets providing an extensive urban animal-human interface in which the general public may have little awareness of circulating infectious diseases. This study focuses on virus surveillance at this interface, combined with culturally responsive science education and community outreach.

microbiology↗

Detection of velogenic avian paramyxoviruses in rock doves in New York City, New York

Avian paramyxovirus 1 (APMV-1), also known as Newcastle disease virus (NDV), causes severe and economically important disease in poultry around the globe. Although a limited amount of APMV-1 strains in urban areas have been characterized, the role of the urban wild bird population as an APMV-1 reservoir is unclear. Since urban birds may have an important role for long-term circulation of the virus, fecal and swab samples were collected by community scientists from wild birds in New York City (NYC), New York, United States. These samples were screened for APMV-1 and genotypically characterized by sequencing of the complete genome. A total of 885 samples were collected from NYC parks and from a local wildlife rehabilitation clinic from October 2020 through June 2021. Eight birds (1.1 %) screened positive for the APMV-1 nucleoprotein gene by conventional reverse transcription polymerase chain reaction (RT-PCR), and two live viruses were isolated via egg culture. The F protein cleavage site, an indicator of pathogenicity, was present in the two samples fully sequenced by next generation sequencing, and positioned 112R R K K R F117. Phylogenetic analysis of the F gene coding sequence classified both isolates into genotype VI, a diverse and predominant genotype responsible for NDV outbreaks in pigeon and dove species worldwide. ImportanceHere we describe the first large-scale effort to screen for APMV-1 in New York Citys wild bird population as part of the New York City Virus Hunters program, a community science initiative. We have characterized two isolates of NDV, with phylogenetic analyses suggesting diversity in established and circulating strains of pigeon paramyxoviruses. Our isolates are also domestic reference strains for future APMV-1 vaccine developments. Future surveillance in this region may contribute to our understanding of NDVs evolution and genetic diversity, as well as inform poultry husbandry and vaccination practices in New York State.

microbiology↗