Ashleigh Matzoll - Academia.edu (original) (raw)

Papers by Ashleigh Matzoll

Research paper thumbnail of Proteomic genotyping: using mass spectrometry to infer SNP genotypes in a forensic context

Forensic Science International: Genetics Supplement Series, 2019

Proteins are an intrinsic part of biological evidence. In the last two decades mass spectrometry ... more Proteins are an intrinsic part of biological evidence. In the last two decades mass spectrometry has revolutionized the analysis of proteins, allowing for thousands of peptides to be detected in a single analysis, including peptides containing single amino acid polymorphisms. Identification of these genetically variant peptides (GVP) allows for inference of the underlying non-synonymous SNP genotype. We have focused on hair proteins as a source of genetic information, discovering and validating 240 GVPs. Using optimized processing, a single hair shaft can obtain random match probabilities (RMPs) of up to 1 in 100 million. We show that GVPinferred genotypes are not affected by the anatomical origin of the hair shaft or pigmentation. Harsh oxidation with peroxide does not affect RMPs. Importantly, GVP-inferred SNP genotypes are statistically compatible with STR-typing and Alu retroelements, with 90% of GVP-inferred SNPs being located greater than 10 million and 75 million bp from the nearest STR or Alu element respectively. We have shown separation of DNA and peptide workflows from the same samples. Recent work has shifted to the use of a targeted peptide assay. When data acquisition of GVPs was dynamically triggered by the detection of a standard peptide, this approach resulted in a 2.5 fold increase in sensitivity and increased confidence in peptide detection. Based on Monte Carlo modeling, we predict this increase in sensitivity will result in RMPs in excess of 1 in 1 trillion from a single hair shaft. Proteomic genotyping can also be applied to any protein matrix, including fingermarks and bone. Proteomic genotyping therefore has potential to complement partial PCR-based DNA typing and to provide other options for investigators.

Research paper thumbnail of Low Yield of Paired Head and Cervical Spine Computed Tomography in Blunt Trauma Evaluation

The Journal of emergency medicine, Jun 1, 2018

With increased computed tomography (CT) utilization, clinicians may simultaneously order head and... more With increased computed tomography (CT) utilization, clinicians may simultaneously order head and neck CT scans, even when injury is suspected only in one region. We sought to determine: 1) the frequency of simultaneous ordering of a head CT scan when a neck CT scan is ordered; 2) the yields of simultaneously ordered head and neck CT scans for clinically significant injury (CSI); and 3) whether injury in one region is associated with a higher rate of injury in the other. This was a retrospective study of all adult patients who received neck CT scans (and simultaneously ordered head CT scans) as part of their blunt trauma evaluation at an urban level 1 trauma center in 2013. An expert panel determined CSI of head and neck injuries. We defined yield as number of patients with injury/number of patients who had a CT scan. Of 3223 patients who met inclusion criteria, 2888 (89.6%) had simultaneously ordered head and neck CT scans. CT yield for CSI in both the head and neck was 0.5% (95% c...

Research paper thumbnail of Seasonal ambient ammonia and ammonium concentrations in a pilot IMPROVE NHx monitoring network in the western United States

Atmospheric Environment, 2014

h i g h l i g h t s A pilot sub-network within IMPROVE was initiated for NHx (NH 3 and NH þ 4). C... more h i g h l i g h t s A pilot sub-network within IMPROVE was initiated for NHx (NH 3 and NH þ 4). Concentrations of ambient NHx in the Rocky Mountain region are investigated. NHx was collected onto acid impregnated filters. Temporal and spatial patterns of NHx concentrations are observed. The role of wildfires as ammonia/ammonium sources is explored.

Research paper thumbnail of Technical note: A 23-year record of twice-weekly aerosol composition measurements at Mauna Loa Observatory

Atmospheric Environment, 2013

This paper introduces a newly compiled data set of atmospheric particulate matter (PM) measuremen... more This paper introduces a newly compiled data set of atmospheric particulate matter (PM) measurements from 1988 through 2010 at Mauna Loa Observatory (MLO), Hawaii, USA. The data are from two samplers: one running only during nighttime hours over multiple days and another running continuously over the same days. The objective of the night-only schedule is to capture samples from Pacific background air masses transported in the free troposphere with minimal contamination from local and marine emissions. Elements characteristic of soils generally exhibit similar concentrations between the continuous and night-only samples, which suggests Pacific background air masses are responsible for the majority of the fine soil aerosol observed at MLO. Sulfur concentrations in the continuous samples often substantially exceed those in night-only samples, suggesting that local sources contribute to the daytime S concentrations at MLO. Trends estimated from Thiel-Sen regression for all 23 years are 1.3% and À1.7% per year for S and Fe (significant at p ¼ 0.05) in the night-only samples; S and Fe trends in the last 10 years are in the same directions and stronger (4.2% and À4.4% per year).

Research paper thumbnail of Proteomic genotyping: using mass spectrometry to infer SNP genotypes in a forensic context

Forensic Science International: Genetics Supplement Series, 2019

Proteins are an intrinsic part of biological evidence. In the last two decades mass spectrometry ... more Proteins are an intrinsic part of biological evidence. In the last two decades mass spectrometry has revolutionized the analysis of proteins, allowing for thousands of peptides to be detected in a single analysis, including peptides containing single amino acid polymorphisms. Identification of these genetically variant peptides (GVP) allows for inference of the underlying non-synonymous SNP genotype. We have focused on hair proteins as a source of genetic information, discovering and validating 240 GVPs. Using optimized processing, a single hair shaft can obtain random match probabilities (RMPs) of up to 1 in 100 million. We show that GVPinferred genotypes are not affected by the anatomical origin of the hair shaft or pigmentation. Harsh oxidation with peroxide does not affect RMPs. Importantly, GVP-inferred SNP genotypes are statistically compatible with STR-typing and Alu retroelements, with 90% of GVP-inferred SNPs being located greater than 10 million and 75 million bp from the nearest STR or Alu element respectively. We have shown separation of DNA and peptide workflows from the same samples. Recent work has shifted to the use of a targeted peptide assay. When data acquisition of GVPs was dynamically triggered by the detection of a standard peptide, this approach resulted in a 2.5 fold increase in sensitivity and increased confidence in peptide detection. Based on Monte Carlo modeling, we predict this increase in sensitivity will result in RMPs in excess of 1 in 1 trillion from a single hair shaft. Proteomic genotyping can also be applied to any protein matrix, including fingermarks and bone. Proteomic genotyping therefore has potential to complement partial PCR-based DNA typing and to provide other options for investigators.

Research paper thumbnail of Low Yield of Paired Head and Cervical Spine Computed Tomography in Blunt Trauma Evaluation

The Journal of emergency medicine, Jun 1, 2018

With increased computed tomography (CT) utilization, clinicians may simultaneously order head and... more With increased computed tomography (CT) utilization, clinicians may simultaneously order head and neck CT scans, even when injury is suspected only in one region. We sought to determine: 1) the frequency of simultaneous ordering of a head CT scan when a neck CT scan is ordered; 2) the yields of simultaneously ordered head and neck CT scans for clinically significant injury (CSI); and 3) whether injury in one region is associated with a higher rate of injury in the other. This was a retrospective study of all adult patients who received neck CT scans (and simultaneously ordered head CT scans) as part of their blunt trauma evaluation at an urban level 1 trauma center in 2013. An expert panel determined CSI of head and neck injuries. We defined yield as number of patients with injury/number of patients who had a CT scan. Of 3223 patients who met inclusion criteria, 2888 (89.6%) had simultaneously ordered head and neck CT scans. CT yield for CSI in both the head and neck was 0.5% (95% c...

Research paper thumbnail of Seasonal ambient ammonia and ammonium concentrations in a pilot IMPROVE NHx monitoring network in the western United States

Atmospheric Environment, 2014

h i g h l i g h t s A pilot sub-network within IMPROVE was initiated for NHx (NH 3 and NH þ 4). C... more h i g h l i g h t s A pilot sub-network within IMPROVE was initiated for NHx (NH 3 and NH þ 4). Concentrations of ambient NHx in the Rocky Mountain region are investigated. NHx was collected onto acid impregnated filters. Temporal and spatial patterns of NHx concentrations are observed. The role of wildfires as ammonia/ammonium sources is explored.

Research paper thumbnail of Technical note: A 23-year record of twice-weekly aerosol composition measurements at Mauna Loa Observatory

Atmospheric Environment, 2013

This paper introduces a newly compiled data set of atmospheric particulate matter (PM) measuremen... more This paper introduces a newly compiled data set of atmospheric particulate matter (PM) measurements from 1988 through 2010 at Mauna Loa Observatory (MLO), Hawaii, USA. The data are from two samplers: one running only during nighttime hours over multiple days and another running continuously over the same days. The objective of the night-only schedule is to capture samples from Pacific background air masses transported in the free troposphere with minimal contamination from local and marine emissions. Elements characteristic of soils generally exhibit similar concentrations between the continuous and night-only samples, which suggests Pacific background air masses are responsible for the majority of the fine soil aerosol observed at MLO. Sulfur concentrations in the continuous samples often substantially exceed those in night-only samples, suggesting that local sources contribute to the daytime S concentrations at MLO. Trends estimated from Thiel-Sen regression for all 23 years are 1.3% and À1.7% per year for S and Fe (significant at p ¼ 0.05) in the night-only samples; S and Fe trends in the last 10 years are in the same directions and stronger (4.2% and À4.4% per year).