726 research outputs found
Impaired decidual natural killer cell regulation of vascular remodelling in early human pregnancies with high uterine artery resistance
During human pregnancy, natural killer (NK) cells accumulate in the maternal decidua, but their specific roles remain to be determined. Decidual NK (dNK) cells are present during trophoblast invasion and uterine spiral artery remodelling. These events are crucial for successful placentation and the provision of an adequate blood supply to the developing fetus. Remodelling of spiral arteries is impaired in the dangerous pregnancy complication pre-eclampsia. We studied dNK cells isolated from pregnancies at 9-14 weeks' gestation, screened by uterine artery Doppler ultrasound to determine resistance indices which relate to the extent of spiral artery remodelling. dNK cells were able to promote the invasive behaviour of fetal trophoblast cells, partly through HGF. Cells isolated from pregnancies with higher resistance indices were less able to do this and secreted fewer pro-invasive factors. dNK cells from pregnancies with normal resistance indices could induce apoptotic changes in vascular smooth muscle and endothelial cells in vitro, events of importance in vessel remodelling, partly through Fas signalling. dNK cells isolated from high resistance index pregnancies failed to induce vascular apoptosis and secreted fewer pro-apoptotic factors. We have modelled the cellular interactions at the maternal-fetal interface and provide the first demonstration of a functional role for dNK cells in influencing vascular cells. A potential mechanism contributing to impaired vessel remodelling in pregnancies with a higher uterine artery resistance is presented. These findings may be informative in determining the cellular interactions contributing to the pathology of pregnancy disorders where remodelling is impaired, such as pre-eclampsia. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd
Clarifying collection details of specimens from Champion Bay, Western Australia, held in the Natural History Museum, Tring
Six bird specimens from Champion Bay (now Geraldton), Western
Australia, were purchased by the British Museum from the dealer E. T. Higgins
and registered in 1867. They included the first known specimen of Painted Finch
Emblema pictum to have been collected after the holotype. All six specimens are of
interest because their species are either rare or otherwise unknown in the Geraldton
area. Widespread drought in the 1860s probably contributed to at least some of the
unusual occurrences but cannot explain them all. Possible alternative locations
for the specimens’ origins are investigated. Biographical details of the probable
collectors of the specimens, A. H. du Boulay and F. H. du Boulay, are explored.© British Ornithologists’ Club 2016 This is an open access article, available to all readers online. The attached file is the published version of the article
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Risk stratification for early-onset fetal growth restriction in women with abnormal serum biomarkers: a retrospective cohort study.
Abnormal maternal serum biomarkers (AMSB), identified through the aneuploidy screening programme, are frequent incidental findings in pregnancy. They are associated with fetal growth restriction (FGR), but previous studies have not examined whether this association is with early-onset ( 34 weeks) FGR; as a result there is no consensus on management. The aims of this study were to determine the prevalence and phenotype of FGR in women with AMSB and test the predictive value of placental sonographic screening to predict early-onset FGR. 1196 pregnant women with AMSB underwent a 21-24 week "placental screen" comprising fetal and placental size, and uterine artery Doppler. Multivariable regression was used to calculate a predictive model for early-onset FGR (birthweight centile < 3rd/< 10th with absent umbilical end-diastolic flow, < 34 weeks). FGR prevalence was high (10.3%), however early-onset FGR was uncommon (2.3%). Placental screening effectively identified early-onset (area under the curve (AUC) 0.93, 95% confidence interval (CI) 0.87-1.00), but not late-onset FGR (AUC 0.70, 95% CI 0.64-0.75). Internal validation demonstrated robust performance for detection/exclusion of early-onset FGR. In this cohort, utilisation of our proposed algorithm with targeted fetal growth and Doppler surveillance, compared with universal comprehensive surveillance would have avoided 1044 scans, potentiating significant cost-saving for maternity services.The work was supported by MFT & Tommy’s charity
A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
Three Earth-sized exoplanets were recently discovered close to the habitable
zone of the nearby ultracool dwarf star TRAPPIST-1. The nature of these planets
has yet to be determined, since their masses remain unmeasured and no
observational constraint is available for the planetary population surrounding
ultracool dwarfs, of which the TRAPPIST-1 planets are the first transiting
example. Theoretical predictions span the entire atmospheric range from
depleted to extended hydrogen-dominated atmospheres. Here, we report a
space-based measurement of the combined transmission spectrum of the two inner
planets made possible by a favorable alignment resulting in their simultaneous
transits on 04 May 2016. The lack of features in the combined spectrum rules
out cloud-free hydrogen-dominated atmospheres for each planet at 10-
levels; TRAPPIST-1 b and c are hence unlikely to harbor an extended gas
envelope as they lie in a region of parameter space where high-altitude
cloud/haze formation is not expected to be significant for hydrogen-dominated
atmospheres. Many denser atmospheres remain consistent with the featureless
transmission spectrum---from a cloud-free water vapour atmosphere to a
Venus-like atmosphere.Comment: Early release to inform further the upcoming review of HST's Cycle 24
proposal
SPECULOOS exoplanet search and its prototype on TRAPPIST
One of the most significant goals of modern science is establishing whether
life exists around other suns. The most direct path towards its achievement is
the detection and atmospheric characterization of terrestrial exoplanets with
potentially habitable surface conditions. The nearest ultracool dwarfs (UCDs),
i.e. very-low-mass stars and brown dwarfs with effective temperatures lower
than 2700 K, represent a unique opportunity to reach this goal within the next
decade. The potential of the transit method for detecting potentially habitable
Earth-sized planets around these objects is drastically increased compared to
Earth-Sun analogs. Furthermore, only a terrestrial planet transiting a nearby
UCD would be amenable for a thorough atmospheric characterization, including
the search for possible biosignatures, with near-future facilities such as the
James Webb Space Telescope. In this chapter, we first describe the physical
properties of UCDs as well as the unique potential they offer for the detection
of potentially habitable Earth-sized planets suitable for atmospheric
characterization. Then, we present the SPECULOOS ground-based transit survey,
that will search for Earth-sized planets transiting the nearest UCDs, as well
as its prototype survey on the TRAPPIST telescopes. We conclude by discussing
the prospects offered by the recent detection by this prototype survey of a
system of seven temperate Earth-sized planets transiting a nearby UCD,
TRAPPIST-1.Comment: Submitted as a chapter in the "Handbook of Exoplanets" (editors: H.
Deeg & J.A. Belmonte; Section Editor: N. Narita). 16 pages, 4 figure
Relationship of cognitive function in patients with schizophrenia in remission to disability: a cross-sectional study in an Indian sample
Background: Cognitive deficits in various domains have been consistently replicated in patients with schizophrenia. Most studies looking at the relationship between cognitive dysfunction and functional disability are from developed countries. Studies from developing countries are few. The purpose of the present study was to compare the neurocognitive function in patients with schizophrenia who were in remission with that of normal controls and to determine if there is a relationship between measures of cognition and functional disability.
<p/>Methods: This study was conducted in the Psychiatric Unit of a General Hospital in Mumbai, India. Cognitive function in 25 patients with schizophrenia in remission was compared to 25 normal controls. Remission was confirmed using the brief psychiatric rating scale (BPRS) and scale for the assessment of negative symptoms (SANS). Subjects were administered a battery of cognitive tests covering aspects of memory, executive function and attention. The results obtained were compared between the groups. Correlation analysis was used to look for relationship between illness factors, cognitive function and disability measured using the Indian disability evaluation and assessment scale.
<p/>Results: Patients with schizophrenia showed significant deficits on tests of attention, concentration, verbal and visual memory and tests of frontal lobe/executive function. They fared worse on almost all the tests administered compared to normal controls. No relationship was found between age, duration of illness, number of years of education and cognitive function. In addition, we did not find a statistically significant relationship between cognitive function and scores on the disability scale.
<p/>Conclusion: The data suggests that persistent cognitive deficits are seen in patients with schizophrenia under remission. The cognitive deficits were not associated with symptomatology and functional disability. It is possible that various factors such as employment and family support reduce disability due to schizophrenia in developing countries like India. Further studies from developing countries are required to explore the relationship between cognitive deficits, functional outcome and the role of socio-cultural variables as protective factors
Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
The current progress in the detection of terrestrial type exoplanets has
opened a new avenue in the characterization of exoplanetary atmospheres and in
the search for biosignatures of life with the upcoming ground-based and space
missions. To specify the conditions favorable for the origin, development and
sustainment of life as we know it in other worlds, we need to understand the
nature of astrospheric, atmospheric and surface environments of exoplanets in
habitable zones around G-K-M dwarfs including our young Sun. Global environment
is formed by propagated disturbances from the planet-hosting stars in the form
of stellar flares, coronal mass ejections, energetic particles, and winds
collectively known as astrospheric space weather. Its characterization will
help in understanding how an exoplanetary ecosystem interacts with its host
star, as well as in the specification of the physical, chemical and biochemical
conditions that can create favorable and/or detrimental conditions for
planetary climate and habitability along with evolution of planetary internal
dynamics over geological timescales. A key linkage of (astro) physical,
chemical, and geological processes can only be understood in the framework of
interdisciplinary studies with the incorporation of progress in heliophysics,
astrophysics, planetary and Earth sciences. The assessment of the impacts of
host stars on the climate and habitability of terrestrial (exo)planets will
significantly expand the current definition of the habitable zone to the
biogenic zone and provide new observational strategies for searching for
signatures of life. The major goal of this paper is to describe and discuss the
current status and recent progress in this interdisciplinary field and to
provide a new roadmap for the future development of the emerging field of
exoplanetary science and astrobiology.Comment: 206 pages, 24 figures, 1 table; Review paper. International Journal
of Astrobiology (2019
ER stress regulates myeloid-derived suppressor cell fate through TRAIL-R–mediated apoptosis
Myeloid-derived suppressor cells (MDSCs) dampen the immune response thorough inhibition of T cell activation and proliferation and often are expanded in pathological conditions. Here, we studied the fate of MDSCs in cancer. Unexpectedly, MDSCs had lower viability and a shorter half-life in tumor-bearing mice compared with neutrophils and monocytes. The reduction of MDSC viability was due to increased apoptosis, which was mediated by increased expression of TNF-related apoptosis–induced ligand receptors (TRAIL-Rs) in these cells. Targeting TRAIL-Rs in naive mice did not affect myeloid cell populations, but it dramatically reduced the presence of MDSCs and improved immune responses in tumor-bearing mice. Treatment of myeloid cells with proinflammatory cytokines did not affect TRAIL-R expression; however, induction of ER stress in myeloid cells recapitulated changes in TRAIL-R expression observed in tumor-bearing hosts. The ER stress response was detected in MDSCs isolated from cancer patients and tumor-bearing mice, but not in control neutrophils or monocytes, and blockade of ER stress abrogated tumor-associated changes in TRAIL-Rs. Together, these data indicate that MDSC pathophysiology is linked to ER stress, which shortens the lifespan of these cells in the periphery and promotes expansion in BM. Furthermore, TRAIL-Rs can be considered as potential targets for selectively inhibiting MDSCs
Interpersonal and affective dimensions of psychopathic traits in adolescents : development and validation of a self-report instrument
We report the development and psychometric evaluations of a self-report instrument designed to screen for psychopathic traits among mainstream community adolescents. Tests of item functioning were initially conducted with 26 adolescents. In a second study the new instrument was administered to 150 high school adolescents, 73 of who had school records of suspension for antisocial behavior. Exploratory factor analysis yielded a 4-factor structure (Impulsivity α = .73, Self-Centredness α = .70, Callous-Unemotional α = .69, and Manipulativeness α = .83). In a third study involving 328 high school adolescents, 130 with records of suspension for antisocial behaviour, competing measurement models were evaluated using confirmatory factor analysis. The superiority of a first-order model represented by four correlated factors that was invariant across gender and age was confirmed. The findings provide researchers and clinicians with a psychometrically strong, self-report instrument and a greater understanding of psychopathic traits in mainstream adolescents
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