344 research outputs found
Short-term health effects in the general population following a major train accident with acrylonitrile in Belgium
Background: Following a train derailment, several tons of acrylonitrile (ACN) exploded, inflamed and part of the ACN ended up in the sewage system of the village of Wetteren. More than 2000 residents living in the close vicinity of the accident and along the sewage system were evacuated. A human biomonitoring study of the adduct N-2-cyanoethylvaline (CEV) was carried out days 14-21 after the accident.
Objectives: (1) To describe the short-term health effects that were reported by the evacuated residents following the train accident, and (2) to explore the association between the CEV concentrations, extrapolated at the time of the accident, and the self-reported short-term health effects.
Methods: Short-term health effects were reported in a questionnaire (n=191). An omnibus test of independence was used to investigate the association between the CEV concentrations and the symptoms. Dose-response relationships were quantified by Generalized Additive Models (GAMs).
Results: The most frequently reported symptoms were local symptoms of irritation. In non-smokers, dose-dependency was observed between the CEV levels and the self-reporting of irritation (p=0.007) and nausea (p=0.007). Almost all non-smokers with CEV concentrations above 100 pmol/g globin reported irritation symptoms. Both absence and presence of symptoms was reported by non-smokers with CEV concentrations below the reference value and up to 10 times the reference value. Residents who visited the emergency services reported more symptoms. This trend was seen for the whole range of CEV concentrations, and thus independently of the dose.
Discussion and conclusion: The present study is one of the first to relate exposure levels to a chemical released during a chemical incident to short-term (self-reported) health effects. A dose-response relation was observed between the CEV concentrations and the reporting of short-term health effects in the non-smokers. Overall, the value of self-reported symptoms to assess exposure showed to be limited. The results of this study confirm that a critical view should be taken when considering self-reported health complaints and that ideally biomarkers are monitored to allow an objective assessment of exposure
E-cadherin and loss of heterozygosity at chromosome 16 in breast carcinogenesis: different genetic pathways in ductal and lobular breast cancer?
Loss of heterozygosity at the long arm of chromosome 16 is one of the most frequent genetic events in breast cancer. In the search for tumour suppressor genes that are the target of loss of heterozygosity at 16q, the E-cadherin gene CDH1 was unveiled by the identification of truncating mutations in the retained copy. However, only lobular tumours showed E-cadherin mutations. Whereas investigations are still devoted to finding the target genes in the more frequent ductal breast cancers, other studies suspect the E-cadherin gene to also be the target in this tumour type. The present article discusses the plausibility of those two lines of thought
Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food
Acknowledgements: The Panel wishes to thank the hearing experts: Tony Fletcher, Philippe Adam Grandjean and Marco Zeilmaker, and EFSA staff members: Davide Arcella for the support provided to this scientific output. The Panel acknowledges all European Competent Authorities that provided occurrence data on perfluoroalkylated substances in food, and supported the data collection for the Comprehensive European Food Consumption Database. The Panel would also like to thank the following authors and co‐authors for providing additional data in relation to their respective studies: Esben Budtz‐Jørgensen, Jerry Campbell, Jessie A Gleason, Berit Granum, Mette Sørenson, Kyle Steenland and Kristina W Whitworth.Peer reviewedPublisher PD
Hakai reduces cell-substratum adhesion and increases epithelial cell invasion
[Abstract]
Background. The dynamic regulation of cell-cell adhesions is crucial for developmental processes, including tissue formation, differentiation and motility. Adherens junctions are important components of the junctional complex between cells and are necessary for maintaining cell homeostasis and normal tissue architecture. E-cadherin is the prototype and best-characterized protein member of adherens junctions in mammalian epithelial cells. Regarded as a tumour suppressor, E-cadherin loss is associated with poor prognosis in carcinoma. The E3 ubiquitin-ligase Hakai was the first reported posttranslational regulator of the E-cadherin complex. Hakai specifically targetted E-cadherin for internalization and degradation and thereby lowered epithelial cell-cell contact. Hakai was also implicated in controlling proliferation, and promoted cancer-related gene expression by increasing the binding of RNA-binding protein PSF to RNAs encoding oncogenic proteins. We sought to investigate the possible implication of Hakai in cell-substratum adhesions and invasion in epithelial cells.
Methods. Parental MDCK cells and MDCK cells stably overexpressing Hakai were used to analyse cell-substratum adhesion and invasion capabilities. Western blot and immunofluoresecence analyses were performed to assess the roles of Paxillin, FAK and Vinculin in cell-substratum adhesion. The role of the proteasome in controlling cell-substratum adhesion was studied using two proteasome inhibitors, lactacystin and MG132. To study the molecular mechanisms controlling Paxillin expression, MDCK cells expressing E-cadherin shRNA in a tetracycline-inducible manner was employed.
Results. Here, we present evidence that implicate Hakai in reducing cell-substratum adhesion and increasing epithelial cell invasion, two hallmark features of cancer progression and metastasis. Paxillin, an important protein component of the cell-matrix adhesion, was completely absent from focal adhesions and focal contacts in Hakai-overexpressing MDCK cells. The expression of Paxillin was found to be regulated by a proteasome-independent mechanism, possibly due to the decreased abundance of E-cadherin.
Conclusions. Taken together, these results suggest that Hakai may be involved in two hallmark aspects of tumour progression, the lowering cell-substratum adhesion and the enhancement of cell invasion.Xunta de Galicia; PS09/24Xunta de Galicia; 10CSA916023P
Structure-Property Optimization of a Series of Imidazopyridines for Visceral Leishmaniasis
Leishmaniasis is a collection of diseases caused by more than 20 Leishmania parasite species that manifest as either visceral, cutaneous, or mucocutaneous leishmaniasis. Despite the significant mortality and morbidity associated with leishmaniasis, it remains a neglected tropical disease. Existing treatments have variable efficacy, significant toxicity, rising resistance, and limited oral bioavailability, which necessitates the development of novel and affordable therapeutics. Here, we report on the continued optimization of a series of imidazopyridines for visceral leishmaniasis and a scaffold hop to a series of substituted 2-(pyridin-2-yl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles with improved absorption, distribution, metabolism, and elimination properties
Skyrmionic order and magnetically induced polarization change in lacunar spinel compounds GaVS and GaMoS: comparative theoretical study
We show how low-energy electronic models derived from the first-principles
electronic structure calculations can help to rationalize the magnetic
properties of two lacunar spinel compounds GaM4S8 with light (M=V) and heavy
(M=Mo) transition-metal elements, which are responsible for different
spin-orbit interaction strength. In the model, each magnetic lattice point was
associated with the M4S4 molecule, and the model itself was formulated in the
basis of molecular Wannier functions constructed for three magnetic t2 bands.
The effects of rhombohedral distortion, spin-orbit interaction, band filling,
and the screening of Coulomb interactions in the t2 bands are discussed in
details. The electronic model is further treated in the superexchange
approximation, which allows us to derive an effective spin model for the energy
and electric polarization () depending on the relative orientation of spins
in the bonds, and study the properties of this model by means of classical
Monte Carlo simulations with the emphasis on the possible formation of the
skyrmionic phase. While isotropic exchange interactions clearly dominate in
GaV4S8, all types of interactions -- isotropic, antisymmetric, and symmetric
anisotropic -- are comparable in the case of GaMo4S8. Particularly, large
uniaxial exchange anisotropy has a profound effect on the properties of
GaMo4S8. On the one hand, it raises the Curie temperature by opening a gap in
the spectrum of magnon excitations. On the other hand, it strongly affects the
skyrmionic phase by playing the role of a molecular field, which facilitates
the formation of skyrmions, but makes them relatively insensitive to the
external magnetic field in the large part of the phase diagram. We predict
reversal of the magnetic dependence of in the case of GaMo4S8 caused by the
reversal of direction of the rhombohedral distortion.Comment: 13 pages, 9 figure
A comparative evaluation of various invasion assays testing colon carcinoma cell lines
Various colon carcinoma cell lines were tested in different invasion assays, i.e. invasion into Matrigel, into confluent fibroblast layers and into chicken heart tissue. Furthermore, invasive capacity and metastatic potential were determined in nude mice. The colon carcinoma cells used were the human cell lines Caco-2, SW-480, SW-620 and HT-29, and the murine lines Colon-26 and -38. None of the human colon carcinoma cells migrated through porous membranes coated with Matrigel; of the murine lines, only Colon-26 did. When incubated in a mixture of Matrigel and culture medium non-invading cells formed spheroid cultures, whereas invading cells showed a stellate outgrowth. Only the heterogeneously shaped (epithelioid and stellate) cells of SW-480 and SW-620 and the spindle-shaped cells of Colon-26 invaded clearly confluent skin and colon fibroblasts as well as chicken heart tissue. However, when transplanted into the caecum of nude and syngeneic mice, all the lines tested were invasive with the exception of Caco-2 cells. We conclude that the outcome of in vitro tests measuring the invasive capacity of neoplastic cells is largely dependent on the test system used. Invasive capacity in vitro is strongly correlated with cells having a spindle cell shape, vimentin expression and E-cadherin down regulation. In contrast, HT-29 and Colon-38 cells having an epithelioid phenotype were clearly invasive and metastatic in vivo, but not in vitro. © 1999 Cancer Research Campaig
CDH1 gene mutations do not contribute in hereditary diffuse gastric cancer in Poland
Hereditary diffuse gastric cancer (HDGC) is a cancer susceptibility syndrome characterized by a high risk of diffuse stomach cancer and lobular breast cancer. HDGC is caused by germline mutations in the CDH1 gene encoding the E-cadherin which is a member of the transmembrane glycoprotein family responsible for calcium-dependent, cell-to-cell adhesion and plays a fundamental role in the maintenance of cell differentiation and the normal architecture of epithelial tissues. Mutations in the CDH1 gene are detected in 30–46% of families that fulfil strong clinical criteria for HDGC and in about 11% of families fulfilling the modified criteria. In the present study, we investigated germline mutations in the CDH1 gene in Polish patients with HDGC. The entire coding sequence of CDH1 gene was analyzed by sequencing in 86 Polish cancer patients from families fulfilling the modified criteria of HDGC. We found several silent mutations including one common variant (c.2076T>C) present in 56 patients, and three rare variants (c.2253C>T, c.1896C>T, c.2634C>T) detected in 2 patients. In addition, we found four rare sequence variants of unknown significance localized in introns. We did not detect any deleterious mutations of the CDH1 gene. CDH1 gene mutations are not present in Polish families with HDGC defined by the modified clinical criteria. Further studies of families with HDGC matching the restrictive criteria for HDGC are needed
Invasion of ovarian cancer cells is induced by PITX2-mediated activation of TGF-β and Activin-A
Background:Most ovarian cancers are highly invasive in nature and the high burden of metastatic disease make them a leading cause of mortality among all gynaecological malignancies. The homeodomain transcription factor, PITX2 is associated with cancer in different tissues. Our previous studies demonstrated increased PITX2 expression in human ovarian tumours. Growing evidence linking activation of TGF-β pathway by homeodomain proteins prompted us to look for the possible involvement of this signalling pathway in PITX2-mediated progression of ovarian cancer.
Methods: The status of TGF-β signalling in human ovarian tissues was assessed by immunohistochemistry. The
expression level of TGFB/INHBA and other invasion-associated genes was measured by quantitative-PCR (Q-PCR)
and Western Blot after transfection/treatments with clones/reagents in normal/cancer cells. The physiological
effect of PITX2 on invasion/motility was checked by matrigel invasion and wound healing assay. The PITX2- and
activin-induced epithelial-mesenchymal transition (EMT) was evaluated by Q-PCR of respective markers and confocal/phase-contrast imaging of cells.
Results: Human ovarian tumours showed enhanced TGF-β signalling. Our study uncovers the PITX2-induced
expression of TGFB1/2/3 as well as INHBA genes (p < 0.01) followed by SMAD2/3-dependent TGF-β signalling
pathway. PITX2-induced TGF-β pathway regulated the expression of invasion-associated genes, SNAI1, CDH1
and MMP9 (p < 0.01) that accounted for enhanced motility/invasion of ovarian cancers. Snail and MMP9 acted
as important mediators of PITX2-induced invasiveness of ovarian cancer cells. PITX2 over-expression resulted in
loss of epithelial markers (p < 0.01) and gain of mesenchymal markers (p < 0.01) that contributed significantly to ovarian oncogenesis. PITX2-induced INHBA expression (p < 0.01) contributed to EMT in both normal and ovarian cancer cells.
Conclusions: Overall, our findings suggest a significant contributory role of PITX2 in promoting invasive
behaviour of ovarian cancer cells through up-regulation of TGFB/INHBA. We have also identified the previously unknown involvement of activin-A in promoting EMT. Our work provides novel mechanistic insights into the invasive behavior of ovarian cancer cells. The extension of this study have the potential for therapeutic applications in future
Inflammatory breast cancer shows angiogenesis with high endothelial proliferation rate and strong E-cadherin expression
status: publishe
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