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result(s) for
"Mullin, A P"
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Neurodevelopmental disorders: mechanisms and boundary definitions from genomes, interactomes and proteomes
2013
Neurodevelopmental disorders such as intellectual disability, autism spectrum disorder and schizophrenia lack precise boundaries in their clinical definitions, epidemiology, genetics and protein–protein interactomes. This calls into question the appropriateness of current categorical disease concepts. Recently, there has been a rising tide to reformulate neurodevelopmental nosological entities from biology upward. To facilitate this developing trend, we propose that identification of unique proteomic signatures that can be strongly associated with patient’s risk alleles and proteome-interactome-guided exploration of patient genomes could define biological mechanisms necessary to reformulate disorder definitions.
Journal Article
Applying Cognitive Design Principles to Formatting HRQOL Instruments
by
Lohr, Kathleen N.
,
Paul A. Mullin
,
Pauline Mc Nulty
in
Cognitive Science - methods
,
Graphic design
,
Humans
2000
Researchers developing or using health-related quality of life (HRQOL) instruments can benefit from knowledge of state-of-the-art formatting methods for self-administered questionnaires. Three objectives in formatting design are: (1) to reduce errors in respondent navigation through the questionnaire that lead to item non-response and question misinterpretation; (2) to reduce respondent and administrative burden; and (3) to enhance respondent motivation in question answering and compliance with the request to participate. Based on an extensive literature review to identify techniques that have been shown to meet these objectives, we developed specific guidelines for HRQOL instruments concerning all aspects of questionnaire formatting. These guidelines represent well-motivated recommendations for improving HRQOL instruments, although their overall impact has not been empirically tested. We applied the guidelines to several HRQOL instruments that are widely used internationally, and obtained approval from the developers for all formatting changes to their instruments. Applying cognitive design principles and empirically substantiated formatting techniques produces an HRQOL instrument formatting with six critical attributes: simple, consistent, organized, natural, clear and attractive. The present paper contributes to the emerging research literature on the cognitive processes by which respondents answer HRQOL questions and demonstrates how 'cognitive aspects of survey methodology' research can improve HRQOL data collection efforts.
Journal Article
Rare coding variation provides insight into the genetic architecture and phenotypic context of autism
2022
Some individuals with autism spectrum disorder (ASD) carry functional mutations rarely observed in the general population. We explored the genes disrupted by these variants from joint analysis of protein-truncating variants (PTVs), missense variants and copy number variants (CNVs) in a cohort of 63,237 individuals. We discovered 72 genes associated with ASD at false discovery rate (FDR) ≤ 0.001 (185 at FDR ≤ 0.05). De novo PTVs, damaging missense variants and CNVs represented 57.5%, 21.1% and 8.44% of association evidence, while CNVs conferred greatest relative risk. Meta-analysis with cohorts ascertained for developmental delay (DD) (
n
= 91,605) yielded 373 genes associated with ASD/DD at FDR ≤ 0.001 (664 at FDR ≤ 0.05), some of which differed in relative frequency of mutation between ASD and DD cohorts. The DD-associated genes were enriched in transcriptomes of progenitor and immature neuronal cells, whereas genes showing stronger evidence in ASD were more enriched in maturing neurons and overlapped with schizophrenia-associated genes, emphasizing that these neuropsychiatric disorders may share common pathways to risk.
Analysis of rare protein-truncating, damaging missense and copy number variants from exome sequencing of 63,237 individuals identifies 72 genes associated with autism spectrum disorder.
Journal Article
Characterisation of genetic regulatory effects for osteoporosis risk variants in human osteoclasts
by
Tickner, Jennifer
,
Kenny, Jacob
,
Dudbridge, Frank
in
Animal Genetics and Genomics
,
Animals
,
Apoptosis
2020
Background
Osteoporosis is a complex disease with a strong genetic contribution. A recently published genome-wide association study (GWAS) for estimated bone mineral density (eBMD) identified 1103 independent genome-wide significant association signals. Most of these variants are non-coding, suggesting that regulatory effects may drive many of the associations. To identify genes with a role in osteoporosis, we integrate the eBMD GWAS association results with those from our previous osteoclast expression quantitative trait locus (eQTL) dataset.
Results
We identify sixty-nine significant
cis
-eQTL effects for eBMD GWAS variants after correction for multiple testing. We detect co-localisation of eBMD GWAS and osteoclast eQTL association signals for 21 of the 69 loci, implicating a number of genes including
CCR5
,
ZBTB38
,
CPE
,
GNA12
,
RIPK3
,
IQGAP1
and
FLCN
. Summary-data-based Mendelian Randomisation analysis of the eBMD GWAS and osteoclast eQTL datasets identifies significant associations for 53 genes, with
TULP4
presenting as a strong candidate for pleiotropic effects on eBMD and gene expression in osteoclasts. By performing analysis using the GARFIELD software, we demonstrate significant enrichment of osteoporosis risk variants among high-confidence osteoclast eQTL across multiple GWAS
P
value thresholds. Mice lacking one of the genes of interest, the apoptosis/necroptosis gene
RIPK3
, show disturbed bone micro-architecture and increased osteoclast number, highlighting a new biological pathway relevant to osteoporosis.
Conclusion
We utilise a unique osteoclast eQTL dataset to identify a number of potential effector genes for osteoporosis risk variants, which will help focus functional studies in this area.
Journal Article
Bone mineral density, osteoporosis, and osteoporotic fractures: a genome-wide association study
by
Pols, HAP
,
Whittaker, P
,
Rivadeneira, F
in
Alleles
,
Biological and medical sciences
,
Bone density
2008
Osteoporosis is diagnosed by the measurement of bone mineral density, which is a highly heritable and multifactorial trait. We aimed to identify genetic loci that are associated with bone mineral density.
In this genome-wide association study, we identified the most promising of 314 075 single nucleotide polymorphisms (SNPs) in 2094 women in a UK study. We then tested these SNPs for replication in 6463 people from three other cohorts in western Europe. We also investigated allelic expression in lymphoblast cell lines. We tested the association between the replicated SNPs and osteoporotic fractures with data from two studies.
We identified genome-wide evidence for an association between bone mineral density and two SNPs (p<5×10
−8). The SNPs were rs4355801, on chromosome 8, near to the
TNFRSF11B (osteoprotegerin) gene, and rs3736228, on chromosome 11 in the
LRP5 (lipoprotein-receptor-related protein) gene. A non-synonymous SNP in the
LRP5 gene was associated with decreased bone mineral density (rs3736228, p=6·3×10
−12 for lumbar spine and p=1·9×10
−4 for femoral neck) and an increased risk of both osteoporotic fractures (odds ratio [OR] 1·3, 95% CI 1·09–1·52, p=0·002) and osteoporosis (OR 1·3, 1·08–1·63, p=0·008). Three SNPs near the
TNFRSF11B gene were associated with decreased bone mineral density (top SNP, rs4355801: p=7·6×10
−10 for lumbar spine and p=3·3×10
−8 for femoral neck) and increased risk of osteoporosis (OR 1·2, 95% CI 1·01–1·42, p=0·038). For carriers of the risk allele at rs4355801, expression of
TNFRSF11B in lymphoblast cell lines was halved (p=3·0×10
−6). 1883 (22%) of 8557 people were at least heterozygous for these risk alleles, and these alleles had a cumulative association with bone mineral density (trend p=2·3×10
−17). The presence of both risk alleles increased the risk of osteoporotic fractures (OR 1·3, 1·08–1·63, p=0·006) and this effect was independent of bone mineral density.
Two gene variants of key biological proteins increase the risk of osteoporosis and osteoporotic fracture. The combined effect of these risk alleles on fractures is similar to that of most well-replicated environmental risk factors, and they are present in more than one in five white people, suggesting a potential role in screening.
Wellcome Trust, European Commission, NWO Investments, Arthritis Research Campaign, Chronic Disease Research Foundation, Canadian Institutes of Health Research, European Society for Clinical and Economic Aspects of Osteoporosis, Genome Canada, Genome Quebéc, Canada Research Chairs, National Health and Medical Research Council of Australia, and European Union.
Journal Article
A biological classification of Huntington's disease: the Integrated Staging System
by
Ross, Christopher A
,
Sivakumaran, Sudhir
,
Mestre, Tiago A
in
Biomarkers
,
Clinical trials
,
Datasets
2022
The current research paradigm for Huntington's disease is based on participants with overt clinical phenotypes and does not address its pathophysiology nor the biomarker changes that can precede by decades the functional decline. We have generated a new research framework to standardise clinical research and enable interventional studies earlier in the disease course. The Huntington's Disease Integrated Staging System (HD-ISS) comprises a biological research definition and evidence-based staging centred on biological, clinical, and functional assessments. We used a formal consensus method that involved representatives from academia, industry, and non-profit organisations. The HD-ISS characterises individuals for research purposes from birth, starting at Stage 0 (ie, individuals with the Huntington's disease genetic mutation without any detectable pathological change) by using a genetic definition of Huntington's disease. Huntington's disease progression is then marked by measurable indicators of underlying pathophysiology (Stage 1), a detectable clinical phenotype (Stage 2), and then decline in function (Stage 3). Individuals can be precisely classified into stages based on thresholds of stage-specific landmark assessments. We also demonstrated the internal validity of this system. The adoption of the HD-ISS could facilitate the design of clinical trials targeting populations before clinical motor diagnosis and enable data standardisation across ongoing and future studies.
Journal Article
The architecture of the Gram-positive bacterial cell wall
2020
The primary structural component of the bacterial cell wall is peptidoglycan, which is essential for viability and the synthesis of which is the target for crucial antibiotics
1
,
2
. Peptidoglycan is a single macromolecule made of glycan chains crosslinked by peptide side branches that surrounds the cell, acting as a constraint to internal turgor
1
,
3
. In Gram-positive bacteria, peptidoglycan is tens of nanometres thick, generally portrayed as a homogeneous structure that provides mechanical strength
4
–
6
. Here we applied atomic force microscopy
7
–
12
to interrogate the morphologically distinct
Staphylococcus aureus
and
Bacillus subtilis
species, using live cells and purified peptidoglycan. The mature surface of live cells is characterized by a landscape of large (up to 60 nm in diameter), deep (up to 23 nm) pores constituting a disordered gel of peptidoglycan. The inner peptidoglycan surface, consisting of more nascent material, is much denser, with glycan strand spacing typically less than 7 nm. The inner surface architecture is location dependent; the cylinder of
B. subtilis
has dense circumferential orientation, while in
S. aureus
and division septa for both species, peptidoglycan is dense but randomly oriented. Revealing the molecular architecture of the cell envelope frames our understanding of its mechanical properties and role as the environmental interface
13
,
14
, providing information complementary to traditional structural biology approaches.
Using high-resolution atomic force microscopy of live cells, the authors present an updated view of the cell walls of both
Staphylococcus aureus
and
Bacillus subtilis
.
Journal Article
Single-cell transcriptomics of the human retinal pigment epithelium and choroid in health and macular degeneration
by
Tucker, Budd A.
,
Giacalone, Joseph C.
,
Stone, Edwin M.
in
Age related diseases
,
Apoptosis
,
Biological Sciences
2019
The human retinal pigment epithelium (RPE) and choroid are complex tissues that provide crucial support to the retina. Disease affecting either of these supportive tissues can lead to irreversible blindness in the setting of age-related macular degeneration. In this study, single-cell RNA sequencing was performed on macular and peripheral regions of RPE-choroid from 7 human donor eyes in 2 independent experiments. In the first experiment, total RPE/choroid preparations were evaluated and expression profiles specific to RPE and major choroidal cell populations were identified. As choroidal endothelial cells represent a minority of the total RPE/choroidal cell population but are strongly implicated in age-related macular degeneration (AMD) pathogenesis, a second single-cell RNA-sequencing experiment was performed using endothelial cells enriched by magnetic separation. In this second study, we identified gene expression signatures along the choroidal vascular tree, classifying the transcriptome of human choriocapillaris, arterial, and venous endothelial cells. We found that the choriocapillaris highly and specifically expresses the regulator of cell cycle gene (RGCC), a gene that responds to complement activation and induces apoptosis in endothelial cells. In addition, RGCC was the most up-regulated choriocapillaris gene in a donor diagnosed with AMD. These results provide a characterization of the human RPE and choriocapillaris transcriptome, offering potential insight into the mechanisms of choriocapillaris response to complement injury and choroidal vascular disease in age-related macular degeneration.
Journal Article