Paul Overton - Academia.edu (original) (raw)
Papers by Paul Overton
International journal of technology assessment in health care, 2018
The aim of this study was to investigate how innovation is defined with respect to new medicines.... more The aim of this study was to investigate how innovation is defined with respect to new medicines. MEDLINE, Embase, and EconLit databases were searched for articles published between January 1, 2010 and May 25, 2016 that described a relevant definition of innovation. Identified definitions were analyzed by mapping the concepts described onto a set of ten dimensions of innovation. In total, thirty-six articles were included, and described a total of twenty-five different definitions of innovation. The most commonly occurring dimension was therapeutic benefit, with novelty and the availability of existing treatments the second and third most common dimensions. Overall, there was little agreement in the published literature on what characteristics of new medicines constitute rewardable innovation. Alignment across countries and among regulators, health technology assessment bodies and payers would help manufacturers define research policies that can drive innovation, but may be challeng...
PharmacoEconomics, Jan 5, 2017
In many healthcare systems, affordability concerns can lead to restrictions on the use of expensi... more In many healthcare systems, affordability concerns can lead to restrictions on the use of expensive efficacious therapies. However, there does not appear to be any consensus as to the terminology used to describe affordability, or the thresholds used to determine whether new drugs are affordable. The aim of this systematic review was to investigate how affordability is defined and measured in healthcare. MEDLINE, EMBASE and EconLit databases (2005-July 2016) were searched using terms covering affordability and budget impact, combined with definitions, thresholds and restrictions, to identify articles describing a definition of affordability with respect to new medicines. Additional definitions were identified through citation searching, and through manual searches of European health technology assessment body websites. In total, 27 definitions were included in the review. Of these, five definitions described affordability in terms of the value of a product; seven considered affordab...
BMC genetics, Jan 2, 2006
The asymmetric segregation of determinants during cell division is a fundamental mechanism for ge... more The asymmetric segregation of determinants during cell division is a fundamental mechanism for generating cell fate diversity during development. In Drosophila, neural precursors (neuroblasts) divide in a stem cell-like manner generating a larger apical neuroblast and a smaller basal ganglion mother cell. The cell fate determinant Prospero and its adapter protein Miranda are asymmetrically localized to the basal cortex of the dividing neuroblast and segregated into the GMC upon cytokinesis. Previous screens to identify components of the asymmetric division machinery have concentrated on embryonic phenotypes. However, such screens are reaching saturation and are limited in that the maternal contribution of many genes can mask the effects of zygotic loss of function, and other approaches will be necessary to identify further genes involved in neuroblast asymmetric division. We have performed a genetic screen in the third instar larval brain using the basal localization of Miranda as a...
Developmental Biology, 2006
The Drosophila melanogaster ventral nerve cord derives from neural progenitor cells called neurob... more The Drosophila melanogaster ventral nerve cord derives from neural progenitor cells called neuroblasts. Individual neuroblasts have unique gene expression profiles and give rise to distinct clones of neurons and glia. The specification of neuroblast identity provides a cell intrinsic mechanism which ultimately results in the generation of progeny which are different from each other. Segment polarity genes have a dual function in early neurogenesis: within distinct regions of the neuroectoderm, they are required both for neuroblast formation and for the specification of neuroblast identity. Previous studies of segment polarity gene function largely focused on neuroblasts that arise within the posterior part of the segment. Here we show that the segment polarity gene midline is required for neuroblast formation in the anterior-most part of the segment. Moreover, midline contributes to the specification of anterior neuroblast identity by negatively regulating the expression of Wingless and positively regulating the expression of Mirror. In the posterior-most part of the segment, midline and its paralog, H15, have partially redundant functions in the regulation of the NB marker Eagle. Hence, the segment polarity genes midline and H15 play an important role in the development of the ventral nerve cord in the anterior-and posterior-most part of the segment.
Development, 2007
Trichomes are cytoplasmic extrusions of epidermal cells. The molecular mechanisms that govern the... more Trichomes are cytoplasmic extrusions of epidermal cells. The molecular mechanisms that govern the differentiation of trichome-producing cells are conserved across species as distantly related as mice and flies. Several signaling pathways converge onto the regulation of a conserved target gene, shavenbaby (svb, ovo), which, in turn, stimulates trichome formation. The Drosophila ventral epidermis consists of the segmental alternation of two cell types that produce either naked cuticle or trichomes called denticles. The binary choice to produce naked cuticle or denticles is affected by the transcriptional regulation of svb, which is sufficient to cell-autonomously direct denticle formation. The expression of svb is regulated by the opposing gradients of two signaling molecules- the epidermal growth factor receptor (Egfr) ligand Spitz (Spi), which activates svb expression, and Wingless (Wg), which represses it. It has remained unclear how these opposing signals are integrated to establi...
Development, 2007
Asymmetric cell divisions generate cell fate diversity during both invertebrate and vertebrate de... more Asymmetric cell divisions generate cell fate diversity during both invertebrate and vertebrate development. Drosophila neural progenitors or neuroblasts (NBs) each divide asymmetrically to produce a larger neuroblast and a smaller ganglion mother cell (GMC). The asymmetric localisation of neural cell fate determinants and their adapter proteins to the neuroblast cortex during mitosis facilitates their preferential segregation to the GMC upon cytokinesis. In this study we report a novel role for the anaphase-promoting complex/cyclosome (APC/C) during this process. Attenuation of APC/C activity disrupts the asymmetric localisation of the adapter protein Miranda and its associated cargo proteins Staufen, Prospero and Brat, but not other components of the asymmetric division machinery. We demonstrate that Miranda is ubiquitylated via its C-terminal domain; removal of this domain disrupts Miranda localisation and replacement of this domain with a ubiquitin moiety restores normal asymmetr...
International journal of technology assessment in health care, 2018
The aim of this study was to investigate how innovation is defined with respect to new medicines.... more The aim of this study was to investigate how innovation is defined with respect to new medicines. MEDLINE, Embase, and EconLit databases were searched for articles published between January 1, 2010 and May 25, 2016 that described a relevant definition of innovation. Identified definitions were analyzed by mapping the concepts described onto a set of ten dimensions of innovation. In total, thirty-six articles were included, and described a total of twenty-five different definitions of innovation. The most commonly occurring dimension was therapeutic benefit, with novelty and the availability of existing treatments the second and third most common dimensions. Overall, there was little agreement in the published literature on what characteristics of new medicines constitute rewardable innovation. Alignment across countries and among regulators, health technology assessment bodies and payers would help manufacturers define research policies that can drive innovation, but may be challeng...
PharmacoEconomics, Jan 5, 2017
In many healthcare systems, affordability concerns can lead to restrictions on the use of expensi... more In many healthcare systems, affordability concerns can lead to restrictions on the use of expensive efficacious therapies. However, there does not appear to be any consensus as to the terminology used to describe affordability, or the thresholds used to determine whether new drugs are affordable. The aim of this systematic review was to investigate how affordability is defined and measured in healthcare. MEDLINE, EMBASE and EconLit databases (2005-July 2016) were searched using terms covering affordability and budget impact, combined with definitions, thresholds and restrictions, to identify articles describing a definition of affordability with respect to new medicines. Additional definitions were identified through citation searching, and through manual searches of European health technology assessment body websites. In total, 27 definitions were included in the review. Of these, five definitions described affordability in terms of the value of a product; seven considered affordab...
BMC genetics, Jan 2, 2006
The asymmetric segregation of determinants during cell division is a fundamental mechanism for ge... more The asymmetric segregation of determinants during cell division is a fundamental mechanism for generating cell fate diversity during development. In Drosophila, neural precursors (neuroblasts) divide in a stem cell-like manner generating a larger apical neuroblast and a smaller basal ganglion mother cell. The cell fate determinant Prospero and its adapter protein Miranda are asymmetrically localized to the basal cortex of the dividing neuroblast and segregated into the GMC upon cytokinesis. Previous screens to identify components of the asymmetric division machinery have concentrated on embryonic phenotypes. However, such screens are reaching saturation and are limited in that the maternal contribution of many genes can mask the effects of zygotic loss of function, and other approaches will be necessary to identify further genes involved in neuroblast asymmetric division. We have performed a genetic screen in the third instar larval brain using the basal localization of Miranda as a...
Developmental Biology, 2006
The Drosophila melanogaster ventral nerve cord derives from neural progenitor cells called neurob... more The Drosophila melanogaster ventral nerve cord derives from neural progenitor cells called neuroblasts. Individual neuroblasts have unique gene expression profiles and give rise to distinct clones of neurons and glia. The specification of neuroblast identity provides a cell intrinsic mechanism which ultimately results in the generation of progeny which are different from each other. Segment polarity genes have a dual function in early neurogenesis: within distinct regions of the neuroectoderm, they are required both for neuroblast formation and for the specification of neuroblast identity. Previous studies of segment polarity gene function largely focused on neuroblasts that arise within the posterior part of the segment. Here we show that the segment polarity gene midline is required for neuroblast formation in the anterior-most part of the segment. Moreover, midline contributes to the specification of anterior neuroblast identity by negatively regulating the expression of Wingless and positively regulating the expression of Mirror. In the posterior-most part of the segment, midline and its paralog, H15, have partially redundant functions in the regulation of the NB marker Eagle. Hence, the segment polarity genes midline and H15 play an important role in the development of the ventral nerve cord in the anterior-and posterior-most part of the segment.
Development, 2007
Trichomes are cytoplasmic extrusions of epidermal cells. The molecular mechanisms that govern the... more Trichomes are cytoplasmic extrusions of epidermal cells. The molecular mechanisms that govern the differentiation of trichome-producing cells are conserved across species as distantly related as mice and flies. Several signaling pathways converge onto the regulation of a conserved target gene, shavenbaby (svb, ovo), which, in turn, stimulates trichome formation. The Drosophila ventral epidermis consists of the segmental alternation of two cell types that produce either naked cuticle or trichomes called denticles. The binary choice to produce naked cuticle or denticles is affected by the transcriptional regulation of svb, which is sufficient to cell-autonomously direct denticle formation. The expression of svb is regulated by the opposing gradients of two signaling molecules- the epidermal growth factor receptor (Egfr) ligand Spitz (Spi), which activates svb expression, and Wingless (Wg), which represses it. It has remained unclear how these opposing signals are integrated to establi...
Development, 2007
Asymmetric cell divisions generate cell fate diversity during both invertebrate and vertebrate de... more Asymmetric cell divisions generate cell fate diversity during both invertebrate and vertebrate development. Drosophila neural progenitors or neuroblasts (NBs) each divide asymmetrically to produce a larger neuroblast and a smaller ganglion mother cell (GMC). The asymmetric localisation of neural cell fate determinants and their adapter proteins to the neuroblast cortex during mitosis facilitates their preferential segregation to the GMC upon cytokinesis. In this study we report a novel role for the anaphase-promoting complex/cyclosome (APC/C) during this process. Attenuation of APC/C activity disrupts the asymmetric localisation of the adapter protein Miranda and its associated cargo proteins Staufen, Prospero and Brat, but not other components of the asymmetric division machinery. We demonstrate that Miranda is ubiquitylated via its C-terminal domain; removal of this domain disrupts Miranda localisation and replacement of this domain with a ubiquitin moiety restores normal asymmetr...