1,700 research outputs found
Population-based estimates of the prevalence of FMR1 expansion mutations in women with early menopause and primary ovarian insufficiency
PURPOSE: Primary ovarian insufficiency before the age of 40 years affects 1% of the female population and is characterized by permanent cessation of menstruation. Genetic causes include FMR1 expansion mutations. Previous studies have estimated mutation prevalence in clinical referrals for primary ovarian insufficiency, but these are likely to be biased as compared with cases in the general population. The prevalence of FMR1 expansion mutations in early menopause (between the ages of 40 and 45 years) has not been published. METHODS: We studied FMR1 CGG repeat number in more than 2,000 women from the Breakthrough Generations Study who underwent menopause before the age of 46 years. We determined the prevalence of premutation (55–200 CGG repeats) and intermediate (45–54 CGG repeats) alleles in women with primary ovarian insufficiency (n = 254) and early menopause (n = 1,881). RESULTS: The prevalence of the premutation was 2.0% in primary ovarian insufficiency, 0.7% in early menopause, and 0.4% in controls, corresponding to odds ratios of 5.4 (95% confidence interval = 1.7–17.4; P = 0.004) for primary ovarian insufficiency and 2.0 (95% confidence interval = 0.8–5.1; P = 0.12) for early menopause. Combining primary ovarian insufficiency and early menopause gave an odds ratio of 2.4 (95% confidence interval = 1.02–5.8; P = 0.04). Intermediate alleles were not significant risk factors for either early menopause or primary ovarian insufficiency. CONCLUSION: FMR1 premutations are not as prevalent in women with ovarian insufficiency as previous estimates have suggested, but they still represent a substantial cause of primary ovarian insufficiency and early menopause
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
FIB-SEM imaging of carbon nanotubes in mouse lung tissue
Ultrastructural characterisation is important for understanding carbon nanotube (CNT) toxicity and how the CNTs interact with cells and tissues. The standard method for this involves using transmission electron microscopy (TEM). However, in particular, the sample preparation, using a microtome to cut thin sample sections for TEM, can be challenging for investigation of regions with agglomerations of large and stiff CNTs because the CNTs cut with difficulty. As a consequence, the sectioning diamond knife may be damaged and the uncut CNTs are left protruding from the embedded block surface excluding them from TEM analysis. To provide an alternative to ultramicrotomy and subsequent TEM imaging, we studied focused ion beam scanning electron microscopy (FIB-SEM) of CNTs in the lungs of mice, and we evaluated the applicability of the method compared to TEM. FIB-SEM can provide serial section volume imaging not easily obtained with TEM, but it is time-consuming to locate CNTs in the tissue. We demonstrate that protruding CNTs after ultramicrotomy can be used to locate the region of interest, and we present FIB-SEM images of CNTs in lung tissue. FIB-SEM imaging was applied to lung tissue from mice which had been intratracheally instilled with two different multiwalled CNTs; one being short and thin, and the other longer and thicker. FIB-SEM was found to be most suitable for detection of the large CNTs (Ø ca. 70 nm), and to be well suited for studying CNT agglomerates in biological samples which is challenging using standard TEM techniques. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-013-7566-x) contains supplementary material, which is available to authorized users
Analyses of HIV-1 integrase sequences prior to South African national HIV-treatment program and available of integrase inhibitors in Cape Town, South Africa
HIV-Integrase (IN) has proven to be a viable target for highly specific HIV-1 therapy. We aimed to
characterize the HIV-1 IN gene in a South African context and identify resistance-associated mutations
(RAMs) against available first and second generation Integrase strand-transfer inhibitors (InSTIs). We
performed genetic analyses on 91 treatment-naïve HIV-1 infected patients, as well as 314 treatmentnaive
South African HIV-1 IN-sequences, downloaded from Los Alamos HIV Sequence Database.
Genotypic analyses revealed the absence of major RAMs in the cohort collected before the broad
availability of combination antiretroviral therapy (cART) and INSTI in South Africa, however, occurred
at a rate of 2.85% (9/314) in database derived sequences. RAMs were present at IN-positions 66, 92,
143, 147 and 148, all of which may confer resistance to Raltegravir (RAL) and Elvitegravir (EVG), but
are unlikely to affect second-generation Dolutegravir (DTG), except mutations in the Q148 pathway.
Furthermore, protein modeling showed, naturally occurring polymorphisms impact the stability of the
intasome-complex and therefore may contribute to an overall potency against InSTIs. Our data suggest
the prevalence of InSTI RAMs, against InSTIs, is low in South Africa, but natural polymorphisms and
subtype-specific differences may influence the effect of individual treatment regimens
Risk Reducing Salpingectomy and Delayed Oophorectomy in high risk women: views of cancer geneticists, genetic counsellors and gynaecological oncologists in the UK
Risk-reducing-salpingectomy and Delayed-Oophorectomy (RRSDO) is being proposed as a two-staged approach in place of RRSO to reduce the risks associated with premature menopause in high-risk women. We report on the acceptability/attitude of UK health professionals towards RRSDO. An anonymised web-based survey was sent to UK Cancer Genetics Group (CGG) and British Gynaecological Cancer Society (BGCS) members to assess attitudes towards RRSDO. Baseline characteristics were described using descriptive statistics. A Chi square test was used to compare categorical, Kendal-tau-b test for ordinal and Mann–Whitney test for continuous variables between two groups. 173/708 (24.4 %) of invitees responded. 71 % respondents (CGG = 57 %/BGCS = 83 %, p = 0.005) agreed with the tubal hypothesis for OC, 55 % (CGG = 42 %/BGCS = 66 %, p = 0.003) had heard of RRSDO and 48 % (CGG = 46 %/BGCS = 50 %) felt evidence was not currently strong enough for introduction into clinical practice. However, 60 % respondents’ (CGG = 48 %/BGCS = 71 %, p = 0.009) favoured offering RRSDO to high-risk women declining RRSO, 77 % only supported RRSDO within a clinical trial (CGG = 78 %/BGCS = 76 %) and 81 % (CGG = 76 %/BGCS = 86 %) advocated a UK-wide registry. Vasomotor symptoms (72 %), impact on sexual function (63 %), osteoporosis (59 %), hormonal-therapy (55 %) and subfertility (48 %) related to premature menopause influenced their choice of RRSDO. Potential barriers to offering the two-stage procedure included lack of data on precise level of benefit (83 %), increased surgical morbidity (79 %), loss of breast cancer risk reduction associated with oophorectomy (68 %), need for long-term follow-up (61 %) and a proportion not undergoing DO (66 %). There were variations in perception between BGCS/CGG members which are probably attributable to differences in clinical focus/expertise between these two groups. Despite concerns, there is reasonable support amongst UK clinicians to offering RRSDO to premenopausal high-risk women wishing to avoid RRSO, within a prospective clinical trial.This work has not been directly funded by any commercial organisation, or charity
Editing of the urease gene by CRISPR-Cas in the diatom Thalassiosira pseudonana
Background: CRISPR-Cas is a recent and powerful addition to the molecular toolbox which allows programmable genome editing. It has been used to modify genes in a wide variety of organisms, but only two alga to date. Here we present a methodology to edit the genome of Thalassiosira pseudonana, a model centric diatom with both ecological significance and high biotechnological potential, using CRISPR-Cas. Results: A single construct was assembled using Golden Gate cloning. Two sgRNAs were used to introduce a precise 37 nt deletion early in the coding region of the urease gene. A high percentage of bi-allelic mutations (≤61.5%) were observed in clones with the CRISPR-Cas construct. Growth of bi-allelic mutants in urea led to a significant reduction in growth rate and cell size compared to growth in nitrate. Conclusions: CRISPR-Cas can precisely and efficiently edit the genome of T. pseudonana. The use of Golden Gate cloning to assemble CRISPR-Cas constructs gives additional flexibility to the CRISPR-Cas method and facilitates modifications to target alternative genes or species
When workplace unionism in global value chains does not function well : exploring the impediments
Improving working conditions at the bottom of global value chains has become a central issue in our global economy. In this battle, trade unionism has been presented as a way for workers to make their voices heard. Therefore, it is strongly promoted by most social standards. However, establishing a well-functioning trade union is not as obvious as it may seem. Using a comparative case study approach, we examine impediments to farm-level unionism in the cut flower industry in Ethiopia. For this purpose, we propose an integrated framework combining two lenses, namely a vertical one (governance and structure of global value chains) and a horizontal one (socio-economic context). We identify 10 impediments that point to three major dimensions contributing to unionisation. These three dimensions include awareness of and interest from workers, legitimacy of trade unions, and capacity of trade unions to act. Furthermore, our results suggest that private social standards may, in certain cases, be counterproductive for the efficient functioning of trade unions. Although we argue that there is no ‘quick fix’ solution to weak workplace unionism at the bottom of global value chains, we stress the importance of considering the dynamics of, and interactions between, the impediments when designing potential support measures that mitigate negative impacts
Evidence of an active volcanic heat source beneath the Pine Island Glacier
Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS
Ovarian cancer
Ovarian cancer is not a single disease and can be subdivided into at least five different histological subtypes that have different identifiable risk factors, cells of origin, molecular compositions, clinical features and treatments. Ovarian cancer is a global problem, is typically diagnosed at a late stage and has no effective screening strategy. Standard treatments for newly diagnosed cancer consist of cytoreductive surgery and platinum-based chemotherapy. In recurrent cancer, chemotherapy, anti-angiogenic agents and poly(ADP-ribose) polymerase inhibitors are used, and immunological therapies are currently being tested. High-grade serous carcinoma (HGSC) is the most commonly diagnosed form of ovarian cancer and at diagnosis is typically very responsive to platinum-based chemotherapy. However, in addition to the other histologies, HGSCs frequently relapse and become increasingly resistant to chemotherapy. Consequently, understanding the mechanisms underlying platinum resistance and finding ways to overcome them are active areas of study in ovarian cancer. Substantial progress has been made in identifying genes that are associated with a high risk of ovarian cancer (such as BRCA1 and BRCA2), as well as a precursor lesion of HGSC called serous tubal intraepithelial carcinoma, which holds promise for identifying individuals at high risk of developing the disease and for developing prevention strategies
Review: The increasing importance of carbon nanotubes and nanostructured conducting polymers in biosensors
The growing need for analytical devices requiring smaller sample volumes, decreased power consumption and improved performance have been driving forces behind the rapid growth in nanomaterials research. Due to their dimensions, nanostructured materials display unique properties not traditionally observed in bulk materials. Characteristics such as increased surface area along with enhanced electrical/optical properties make them suitable for numerous applications such as nanoelectronics, photovoltaics and chemical/biological sensing. In this review we examine the potential that exists to use nanostructured materials for biosensor devices. By incorporating nanomaterials, it is possible to achieve enhanced sensitivity, improved response time and smaller size. Here we report some of the success that has been achieved in this area. Many nanoparticle and nanofibre geometries are particularly relevant, but in this paper we specifically focus on organic nanostructures, reviewing conducting polymer nanostructures and carbon nanotubes
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