83 research outputs found
Molecular expression associated with vibrissa follicle development and differentiation
The hair follicle is a complex mini-organ formed as a result of epithelial mesenchymal interactions, provided by three different stem cell sources: epithelial, neural crest and mesenchymal. Hair follicle morphogenesis is directed by a distinct set of molecular signals which are unique to each stage of development. These interactions continue into the adult cycle, represented by periods of rapid growth (anagen), apoptosis driven regression (catagen), a period of relative quiescence (telogen) and shedding of the club hair (exogen). Many of the molecules involved have been elucidated such as Wnts, Bmps, Fgfs, TGF-ßs and Shh amongst others. However, the nature of their regulation and effect on gene expression is still unclear. Id proteins are emerging as powerful players in the transcriptional control of many fundamental biological processes, such as the cell cycle, proliferation and differentiation, apoptosis and lineage commitment. As a result, the expression patterns of Id2 and Ids were investigated by immunocytochemistry in developing and adult vibrissae. Wistar rats aged E14toP4 were used to cover all stages of vibrissae development (stages 0-6+) and 3-6 month old rats for the adult stages. This thesis reports that high Id2 expression was seen in specialised neuroendocrine cells (Merkel cells) of the hair follicle and basal epidermis, confirmed by co-expression of the Merkel cell marker, cytokeratin-20. This post-mitotic Id2 expression continued through postnatal ages and into the adult follicle. Staining with Id3 was characterised by cytoplasmic, basally polarised expression in the epithelia of stage 1-4 follicles. After this stage, expression switched to being nuclear with high levels in many different cell types including the dermal papilla, dermal sheath and outer root sheath, ш and Id3 expression was also investigated in retinole acid induced differentiation of E13.5 and E14 mystacial pads, studying the glandular morphogenesis of vibrissae and the effect on Id protein expression. Ш and Id3 immunoreactivity was cytoplasmic and polarised but no evidence of nuclear staining was seen.Id2 and ИЗ expression in developing vibrissae is reported here for the first time, describing the profiles of these proteins during hair follicle development and differentiation. These findings highlight an important cytoplasmic role for Id proteins in development and may have implications for reciprocal epithelial- mesenchymal interactions, pattern formation and stem cells in the hair follicle
Making body work sequences visible: an ethnographic study of acute orthopaedic hospital wards
Within health and social care, academic attention is increasingly paid to understanding the nature and centrality of body work. Relatively little is known about how and where body work specifically fits into the wider work relations that produce it in healthcare settings. We draw on ethnographic observations of staff practice in three National Health Service acute hospital wards in the United Kingdom to make visible the micro-processes of patient care sequences including both body work and the work contextualising and supporting it. Our data, produced in 2015, show body work interactions in acute care to be critically embedded within a context of initiating, preparing, moving and restoring and proceeding. Shades of privacy and objectification of the body are present throughout these sequences. While accomplishing tasks away from the physical body, staff members must also maintain physical and cognitive work focussed on producing body work. Thus, patient care is necessarily complex, requiring much staff time and energy to deliver it. We argue that by making visible the micro-processes that hospital patient care depends on, including both body work and the work sequences supporting it, the complex physical and cognitive workload required to deliver care can be better recognised. (A virtual version of this abstract is available at: https://www.youtube.com/channel/UC_979cmCmR9rLrKuD7z0ycA)
Imputation of Orofacial Clefting Data Identifies Novel Risk Loci and Sheds Light on the Genetic Background of Cleft Lip ± Cleft Palate and Cleft Palate Only.
Abstract Nonsyndromic cleft lip with or without cleft palate (nsCL/P) is among the most common human birth defects with multifactorial etiology. Here, we present results from a genome-wide imputation study of nsCL/P in which, after adding replication cohort data, four novel risk loci for nsCL/P are identified (at chromosomal regions 2p21, 14q22, 15q24 and 19p13). On a systematic level, we show that the association signalswithin this high-density datasetare enriched in functionally-relevant genomic regions that are active in both human neural crest cells (hNCC) and mouse embryonic craniofacial tissue.
This enrichment is also detectable in hNCC regions primed for later activity. Using GCTA analyses, we suggest that 30% of the estimated variance in risk for nsCL/P in the European population can be attributed to common variants, with 25.5% contributed to by the 24 risk loci known to date. For each of these, we identify credible SNPs using a Bayesian refinementapproach, with two loci harbouring only one probable causal variant. Finally, we demonstrate that there is no polygenic component of nsCL/P detectable that is shared with nonsyndromic cleft palate only (nsCPO). Our data suggest that, while common variants are strongly contributing to risk for nsCL/P, they do not seem to be involved in nsCPO which might be more often caused by rare deleterious variants. Our study generates novel insights into both nsCL/P and nsCPO etiology and provides a systematic framework for research into craniofacial development and malformation
Extending the allelic spectrum at noncoding risk loci of orofacial clefting
Genome-wide association studies (GWAS) have generated unprecedented insights into the genetic etiology of orofacial clefting (OFC). The moderate effect sizes of associated noncoding risk variants and limited access to disease-relevant tissue represent considerable challenges for biological interpretation of genetic findings. As rare variants with stronger effect sizes are likely to also contribute to OFC, an alternative approach to delineate pathogenic mechanisms is to identify private mutations and/or an increased burden of rare variants in associated regions. This report describes a framework for targeted resequencing at selected noncoding risk loci contributing to nonsyndromic cleft lip with/without cleft palate (nsCL/P), the most frequent OFC subtype. Based on GWAS data, we selected three risk loci and identified candidate regulatory regions (CRRs) through the integration of credible SNP information, epigenetic data from relevant cells/tissues, and conservation scores. The CRRs (total 57 kb) were resequenced in a multiethnic study population (1061 patients; 1591 controls), using single-molecule molecular inversion probe technology. Combining evidence from in silico variant annotation, pedigree- and burden analyses, we identified 16 likely deleterious rare variants that represent new candidates for functional studies in nsCL/P. Our framework is scalable and represents a promising approach to the investigation of additional congenital malformations with multifactorial etiology
Optimising care for patients with cognitive impairment and dementia following hip fracture
The global shift in demographics towards aging populations is leading to a commensurate increase in age-related disease and frailty. It is essential to optimise health services to meet current needs and prepare for anticipated future demands. This paper explores issues impacting on people living with cognitive impairment and/or dementia who experience a hip fracture and are cared for in acute settings. This is important given the high mortality and morbidity associated with this population. Given the current insufficiency of clear evidence on optimum rehabilitation of this patient group, this paper explored three key themes namely: recognition of cognitive impairment, response by way of training and education of staff to optimise care for this patient group and review of the importance of outcomes measures. Whilst there is currently insufficient evidence to draw conclusions about the optimal ways of caring for patients living with dementia following hip fracture, this paper concludes that future research should improve understanding of healthcare staff education to improve the outcomes for this important group of patients
Boron-doped diamond dual-plate deep-microtrench device for generator-collector sulfide sensing
International audienceA BDD-BDD dual-plate microtrench electrode with 6 μm inter-electrode spacing is investigated using generator-collector electrochemistry and shown to give microtrench depth-dependent sulfide detection down to the μM levels. The effect of the microtrench depth is compared for a “shallow” 44 μm and a “deep” 180 μm microtrench and linked to the reduction of oxygen to hydrogen peroxide which interferes with sulfide redox cycling. With a deeper microtrench and a fixed collector potential at −1.4 V vs. SCE, two distinct redox cycling potential domains are observed at 0.0 V vs. SCE (2-electron) and at 1.1 V vs. SCE (6-electron)
New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
Maternal gestational vitamin D supplementation and offspring bone health (MAVIDOS): a multicentre, double-blind, randomised placebo-controlled trial.
BACKGROUND: Maternal vitamin D status has been associated with bone mass of offspring in many, but not all, observational studies. However, maternal vitamin D repletion during pregnancy has not yet been proven to improve offspring bone mass in a randomised controlled trial. We aimed to assess whether neonates born to mothers supplemented with vitamin D during pregnancy have greater whole-body bone mineral content (BMC) at birth than those of mothers who had not received supplementation. METHODS: The Maternal Vitamin D Osteoporosis Study (MAVIDOS) was a multicentre, double-blind, randomised, placebo-controlled trial that recruited pregnant women from three study sites in the UK (Southampton, Oxford, and Sheffield). Eligible participants were older than 18 years, with a singleton pregnancy, gestation of less than 17 weeks, and a serum 25-hydroxyvitamin D (25[OH]D) concentration of 25-100 nmol/L at 10-17 weeks' gestation. P'articipants were randomly assigned (1:1), in randomly permuted blocks of ten, to either cholecalciferol 1000 IU/day or matched placebo, taken orally, from 14 weeks' gestation (or as soon as possible before 17 weeks' gestation if recruited later) until delivery. Participants and the research team were masked to treatment allocation. The primary outcome was neonatal whole-body BMC, assessed within 2 weeks of birth by dual-energy x-ray absorptiometry (DXA), analysed in all randomly assigned neonates who had a usable DXA scan. Safety outcomes were assessed in all randomly assigned participants. This trial is registered with the International Standard Randomised Controlled Trial registry, ISRCTN 82927713, and the European Clinical Trials Database, EudraCT 2007-001716-23. FINDINGS: Between Oct 10, 2008, and Feb 11, 2014, we randomly assigned 569 pregnant women to placebo and 565 to cholecalciferol 1000 IU/day. 370 (65%) neonates in the placebo group and 367 (65%) neonates in the cholecalciferol group had a usable DXA scan and were analysed for the primary endpoint. Neonatal whole-body BMC of infants born to mothers assigned to cholecalciferol 1000 IU/day did not significantly differ from that of infants born to mothers assigned to placebo (61·6 g [95% CI 60·3-62·8] vs 60·5 g [59·3-61·7], respectively; p=0·21). We noted no significant differences in safety outcomes, apart from a greater proportion of women in the placebo group with severe post-partum haemorrhage than those in the cholecalciferol group (96 [17%] of 569 mothers in the placebo group vs 65 [12%] of 565 mothers in the cholecalciferol group; p=0·01). No adverse events were deemed to be treatment related. INTERPRETATION: Supplementation of women with cholecalciferol 1000 IU/day during pregnancy did not lead to increased offspring whole-body BMC compared with placebo, but did show that 1000 IU of cholecalciferol daily is sufficient to ensure that most pregnant women are vitamin D replete, and it is safe. These findings support current approaches to vitamin D supplementation in pregnancy. Results of the ongoing MAVIDOS childhood follow-up study are awaited. FUNDING: Arthritis Research UK, Medical Research Council, Bupa Foundation, and National Institute for Health Research
Hair follicles are required for optimal growth during lateral skin expansion
The hair follicles and the interfollicular epidermis of intact mature skin are maintained by distinct stem cell populations. Upon wounding, however, emigration of hair follicle keratinocytes to the interfollicular epidermis plays a role in acute stages of healing. In addition to this repair function, rapidly cycling cells of the upper hair follicle have been observed transiting to the interfollicular epidermis in neonatal skin. Here we report that an absence of hair follicle development leads to shortening and kinking of the mouse tail. These skeletal defects are reduced by stimulating keratinocyte proliferation, suggesting that they arise from impaired epidermal expansion. We confirm that rapidly cycling cells of the hair follicle emigrate to the interfollicular epidermis of the neonatal tail. These results suggest that an absence of hair follicles results in impaired skin growth that is unable to keep pace with the rapidly elongating axial skeleton of the tail. Thus, in addition to their role in wound repair, hair follicles can make a significant contribution to lateral expansion of the interfollicular epidermis in the absence of trauma
IMI - Myopia Genetics Report
The knowledge on the genetic background of refractive error and myopia has expanded
dramatically in the past few years. This white paper aims to provide a concise summary of
current genetic findings and defines the direction where development is needed.
We performed an extensive literature search and conducted informal discussions with key
stakeholders. Specific topics reviewed included common refractive error, any and high
myopia, and myopia related to syndromes.
To date, almost 200 genetic loci have been identified for refractive error and myopia, and risk
variants mostly carry low risk but are highly prevalent in the general population. Several
genes for secondary syndromic myopia overlap with those for common myopia. Polygenic
risk scores show overrepresentation of high myopia in the higher deciles of risk. Annotated
genes have a wide variety of functions, and all retinal layers appear to be sites of expression.
The current genetic findings offer a world of new molecules involved in myopiagenesis. As
the missing heritability is still large, further genetic advances are needed. This Committee
recommends expanding large-scale, in-depth genetic studies using complementary big data
analytics, consideration of gene-environment effects by thorough measurement of environmental exposures, and focus on subgroups with extreme phenotypes and high familial
occurrence. Functional characterization of associated variants is simultaneously needed to
bridge the knowledge gap between sequence variance and consequence for eye growth
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