793 research outputs found
Bisphenol A shapes children’s brain and behavior: towards an integrated neurotoxicity assessment including human data
The authors gratefully acknowledge editorial assistance provided by Richard
Davies. VM is under contract within the Human Biomonitoring for Europe
Project (European Union Commission H2020-EJP-HBM4EU). The authors acknowledge the funding received from the Biomedical Research Networking
Center-CIBER de Epidemiología y Salud Pública (CIBERESP), and the Instituto
de Salud Carlos III (ISCIII) (FIS-PI16/01820 and FIS-PI16/01812). The funders
had no role in the study design, data.Concerns about the effects of bisphenol A (BPA) on human brain and behavior are not novel; however, Grohs and
colleagues have contributed groundbreaking data on this topic in a recent issue of Environmental Health. For the first time,
associations were reported between prenatal BPA exposure and differences in children’s brain microstructure, which
appeared to mediate the association between this exposure and children’s behavioral symptoms. Findings in numerous
previous mother-child cohorts have pointed in a similar worrying direction, linking higher BPA exposure during pregnancy
to more behavioral problems throughout childhood as assessed by neuropsychological questionnaires. Notwithstanding, this
body of work has not been adequately considered in risk assessment. From a toxicological perspective, results are now
available from the CLARITY-BPA consortium, designed to reconcile academic and regulatory toxicology findings. In fact, the
brain has consistently emerged as one of the most sensitive organs disrupted by BPA, even at doses below those
considered safe by regulatory agencies such as the European Food Safety Authority (EFSA). In this Commentary, we
contextualize the results of Grohs et al. within the setting of previous epidemiologic and CLARITY-BPA data and express our
disquiet about the “all-or-nothing” criterion adopted to select human data in a recent EFSA report on the appraisal
methodology for their upcoming BPA risk assessment. We discuss the most relevant human studies, identify emerging
patterns, and highlight the need for adequate assessment and interpretation of the increasing epidemiologic literature in this
field in order to support decision-making. With the aim of avoiding a myopic or biased selection of a few studies in
traditional risk assessment procedures, we propose a future reevaluation of BPA focused on neurotoxicity and based on a
systematic and comprehensive integration of available mechanistic, animal, and human data. Taken together, the
experimental and epidemiologic evidence converge in the same direction: BPA is a probable developmental neurotoxicant
at low doses. Accordingly, the precautionary principle should be followed, progressively implementing stringent preventive
policies worldwide, including the banning of BPA in food contact materials and thermal receipts, with a focus on the
utilization of safer substitutes.European Union (EU): H2020-EJP-HBM4EUBiomedical Research Networking Center-CIBER de Epidemiologia y Salud Publica (CIBERESP)Instituto de Salud Carlos III
FIS-PI16/01820
FIS-PI16/0181
The Sec1/Munc18 protein Vps45 regulates cellular levels of its SNARE binding partners Tlg2 and Snc2 in Saccharomyces cerevisiae
Intracellular membrane trafficking pathways must be tightly regulated to ensure proper functioning of all eukaryotic cells. Central to membrane trafficking is the formation of specific SNARE (soluble N-ethylmeleimide-sensitive factor attachment protein receptor) complexes between proteins on opposing lipid bilayers. The Sec1/Munc18 (SM) family of proteins play an essential role in SNARE-mediated membrane fusion, and like the SNAREs are conserved through evolution from yeast to humans. The SM protein Vps45 is required for the formation of yeast endosomal SNARE complexes and is thus essential for traffic through the endosomal system. Here we report that, in addition to its role in regulating SNARE complex assembly, Vps45 regulates cellular levels of its SNARE binding partners: the syntaxin Tlg2 and the v-SNARE Snc2: Cells lacking Vps45 have reduced cellular levels of Tlg2 and Snc2; and elevation of Vps45 levels results in concomitant increases in the levels of both Tlg2 and Snc2. As well as regulating traffic through the endosomal system, the Snc v-SNAREs are also required for exocytosis. Unlike most vps mutants, cells lacking Vps45 display multiple growth phenotypes. Here we report that these can be reversed by selectively restoring Snc2 levels in vps45 mutant cells. Our data indicate that as well as functioning as part of the machinery that controls SNARE complex assembly, Vps45 also plays a key role in determining the levels of its cognate SNARE proteins; another key factor in regulation of membrane traffic
Six-Loop Anomalous Dimension of Twist-Three Operators in N=4 SYM
The result for the six-loop anomalous dimension of twist-three operators in
the planar N=4 SYM theory is presented. The calculations were performed along
the paper arXiv:0912.1624. This result provides a new data for testing the
proposed spectral equations for planar AdS/CFT correspondence.Comment: 19 pages, typos corrected, details adde
Double-logs, Gribov-Lipatov reciprocity and wrapping
We study analytical properties of the five-loop anomalous dimension of
twist-2 operators at negative even values of Lorentz spin. Following L. N.
Lipatov and A. I. Onishchenko, we have found two possible generalizations of
double-logarithmic equation, which allow to predict a lot of poles of anomalous
dimension of twist-2 operators at all orders of perturbative theory from the
known results. Second generalization is related with the reciprocity-respecting
function, which is a single-logarithmic function in this case. We have found,
that the knowledge of first orders of the reciprocity-respecting function gives
all-loop predictions for the highest poles. Obtained predictions can be used
for the reconstruction of a general form of the wrapping corrections for
twist-2 operators.Comment: 17 pages, references adde
Bisphenol A exposure in Mexico City and risk of prematurity: a pilot nested case control study
Abstract Background Presence of Bisphenol A (BPA) has been documented worldwide in a variety of human biological samples. There is growing evidence that low level BPA exposure may impact placental tissue development and thyroid function in humans. The aim of this present pilot study was to determine urinary concentrations of BPA during the last trimester of pregnancy among a small subset of women in Mexico City, Mexico and relate these concentrations to risk of delivering prematurely. Methods A nested case-control subset of 60 participants in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) study in Mexico City, Mexico were selected based on delivering less than or equal to 37 weeks of gestation and greater than 37 weeks of gestation. Third trimester archived spot urine samples were analyzed by online solid phase extraction coupled with high performance liquid chromatography isotope dilution tandem mass spectrometry. Results BPA was detected in 80.0% (N = 48) of the urine samples; total concentrations ranged from < 0.4 μg/L to 6.7 μg/L; uncorrected geometric mean was 1.52 μg/L. The adjusted odds ratio of delivering less than or equal to 37 weeks in relation to specific gravity adjusted third trimester BPA concentration was 1.91 (95%CI 0.93, 3.91, p-value = 0.08). When cases were further restricted to births occurring prior to the 37th week (n = 12), the odds ratio for specific-gravity adjusted BPA was larger and statistically significant (p < 0.05). Conclusions This is the first study to document measurable levels of BPA in the urine of a population of Mexican women. This study also provides preliminary evidence, based on a single spot urine sample collected during the third trimester, that pregnant women who delivered less than or equal to 37 weeks of gestation and prematurely (< 37 weeks) had higher urinary concentrations of BPA compared to women delivering after 37 weeks.http://deepblue.lib.umich.edu/bitstream/2027.42/78251/1/1476-069X-9-62.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78251/2/1476-069X-9-62.pdfPeer Reviewe
Urinary Bisphenol A and Type-2 Diabetes in U.S. Adults: Data from NHANES 2003-2008
Bisphenol A (BPA) is found in plastics and other consumer products; exposure may lead to insulin resistance and development of type-2 diabetes mellitus (T2DM) through over-activation of pancreatic β-cells. Previous studies using data from the National Health and Nutrition Examination Survey (NHANES) showed an inconsistent association between prevalence of self-reported T2DM and urinary BPA. We used a different diagnosis method of T2DM (hemoglobin A1c (HbA1c)) with a larger subset of NHANES.We analyzed data from 4,389 adult participants who were part of a sub-study of environmental phenol measurements in urine from three NHANES cycles from 2003 to 2008. T2DM was defined as having a HbA1c ≥6.5% or use of diabetes medication. The weighted prevalence of T2DM was 9.2%. Analysis of the total sample revealed that a two-fold increase in urinary BPA was associated with an odds ratio (OR) of 1.08 of T2DM (95% confidence interval (CI), 1.02 to 1.16), after controlling for potential confounders. However, when we examined each NHANES cycle individually, we only found a statistically significant association in the 2003/04 cycle (n = 1,364, OR = 1.23 (95% CI, 1.07 to 1.42) for each doubling in urinary BPA). We found no association in either the NHANES cycle from 2005/06 (n = 1,363, OR = 1.05 (95% CI, 0.94 to 1.18)); or 2007/08 (n = 1,662, OR = 1.06 (95% CI, 0.91 to 1.23)). Similar patterns of associations between BPA and continuous HbA1c were also observed.Although higher urinary BPA was associated with elevated HbA1c and T2DM in the pooled analysis, it was driven by data from only one NHANES cycle. Additional studies, especially of a longitudinal design with repeated BPA measurements, are needed to further elucidate the association between BPA and T2DM
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
Requirements Analysis for an Open Research Knowledge Graph
Current science communication has a number of drawbacks and bottlenecks which
have been subject of discussion lately: Among others, the rising number of
published articles makes it nearly impossible to get an overview of the state
of the art in a certain field, or reproducibility is hampered by fixed-length,
document-based publications which normally cannot cover all details of a
research work. Recently, several initiatives have proposed knowledge graphs
(KGs) for organising scientific information as a solution to many of the
current issues. The focus of these proposals is, however, usually restricted to
very specific use cases. In this paper, we aim to transcend this limited
perspective by presenting a comprehensive analysis of requirements for an Open
Research Knowledge Graph (ORKG) by (a) collecting daily core tasks of a
scientist, (b) establishing their consequential requirements for a KG-based
system, (c) identifying overlaps and specificities, and their coverage in
current solutions. As a result, we map necessary and desirable requirements for
successful KG-based science communication, derive implications and outline
possible solutions.Comment: Accepted for publishing in 24th International Conference on Theory
and Practice of Digital Libraries, TPDL 202
Recent translational research: circulating tumor cells in breast cancer patients
In breast cancer patients, hematogenous tumor cell dissemination can be detected, even at the single cell level, by applying immunocytochemical and molecular assays. Various methods for the detection of circulating tumor cells in the peripheral blood have been described. Results from recently reported studies suggest that circulating tumor cell levels may serve as a prognostic marker and for the early assessment of therapeutic response in patients with metastatic breast cancer. However, in early-stage breast cancer, the impact of circulating tumor cells is less well established than the presence of disseminated tumor cells in bone marrow; several clinical studies have demonstrated that cells of the latter type are an independent prognostic factor at primary diagnosis. In this article we briefly summarize recent studies examining the presence of circulating tumor cells in the blood and discuss further clinical applications
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