Lead and zinc concentrations in household dust and toenails of the residents (Estarreja, Portugal): a source-pathway-fate model.

This paper describes a methodology developed to assess and apportion probable indoor and outdoor sources of potentially toxic elements while identifying chemical signatures in the household dust collected from private homes in an industrial city (Estarreja, central Portugal). Oral bioaccessibility estimates and the chemical composition of toenail clippings were used to assess indoor dust ingestion as a potential exposure pathway and further investigate exposure-biomarker relationships. Indoor and paired outdoor dust samples were collected from each household. A total of 30 individuals, who provided toenail clippings and a self-reported questionnaire, were recruited for the study. Total concentrations of 34 elements, including lead and zinc, were determined in washed toenail samples and household dust via Inductively Coupled Plasma-Mass Spectrometry. The oral bioaccessibility was estimated using the Unified BARGE Method. The enrichment factor shows that lead was enriched (10 < EF < 100) while zinc (EF > 100) was anomalously enriched in the household dust, thus indicating potential exposure in the home environment. The results from principal component analysis coupled to cluster analysis and linear discriminant analysis suggested that mixed contamination derived from multiple sources with a predominance of biomass burning. Stepwise multiple linear regression analysis was performed to model toenail data using the indoor dust elemental composition. Whereas the model obtained for lead was not reliable, indoor dust zinc and antimony contents arose as good predictors of toenail zinc. The exposure-biomarker relationships seem to be influenced by the oral bioaccessibility of the elements.

Proline-Rich Homeodomain protein (PRH/HHEX) is a suppressor of breast tumour growth.

Breast tumours progress from hyperplasia to ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC). PRH/HHEX (proline-rich homeodomain/haematopoietically expressed homeobox) is a transcription factor that displays both tumour suppressor and oncogenic activity in different disease contexts; however, the role of PRH in breast cancer is poorly understood. Here we show that nuclear localization of the PRH protein is decreased in DCIS and IBC compared with normal breast. Our previous work has shown that PRH phosphorylation by protein kinase CK2 prevents PRH from binding to DNA and regulating the transcription of multiple genes encoding growth factors and growth factor receptors. Here we show that transcriptionally inactive phosphorylated PRH is elevated in DCIS and IBC compared with normal breast. To determine the consequences of PRH loss of function in breast cancer cells, we generated inducible PRH depletion in MCF-7 cells. We show that PRH depletion results in increased MCF-7 cell proliferation in part at least due to increased vascular endothelial growth factor signalling. Moreover, we demonstrate that PRH depletion increases the formation of breast cancer cells with cancer stem cell-like properties. Finally, and in keeping with these findings, we show that PRH overexpression inhibits the growth of mammary tumours in mice. Collectively, these data indicate that PRH plays a tumour suppressive role in the breast and they provide an explanation for the finding that low PRH mRNA levels are associated with a poor prognosis in breast cancer.

Transcriptional Regulation During Zygotic Genome Activation in Zebrafish and Other Anamniote Embryos.

Embryo development commences with the fusion of two terminally differentiated haploid gametes into the totipotent fertilized egg, which through a series of major cellular and molecular transitions generate a pluripotent cell mass. The activation of the zygotic genome occurs during the so-called maternal to zygotic transition and prepares the embryo for zygotic takeover from maternal factors, in the control of the development of cellular lineages during differentiation. Recent advances in next generation sequencing technologies have allowed the dissection of the genomic and epigenomic processes mediating this transition. These processes include reorganization of the chromatin structure to a transcriptionally permissive state, changes in composition and function of structural and regulatory DNA-binding proteins, and changeover of the transcriptome as it is overhauled from that deposited by the mother in the oocyte to a zygotically transcribed complement. Zygotic genome activation in zebrafish occurs 10 cell cycles after fertilization and provides an ideal experimental platform for elucidating the temporal sequence and dynamics of establishment of a transcriptionally active chromatin state and helps in identifying the determinants of transcription activation at polymerase II transcribed gene promoters. The relatively large number of pluripotent cells generated by the fast cell divisions before zygotic transcription provides sufficient biomass for next generation sequencing technology approaches to establish the temporal dynamics of events and suggest causative relationship between them. However, genomic and genetic technologies need to be improved further to capture the earliest events in development, where cell number is a limiting factor. These technologies need to be complemented with precise, inducible genetic interference studies using the latest genome editing tools to reveal the function of candidate determinants and to confirm the predictions made by classic embryological tools and genome-wide assays. In this review we summarize recent advances in the characterization of epigenetic regulation, transcription control, and gene promoter function during zygotic genome activation and how they fit with old models for the mechanisms of the maternal to zygotic transition. This review will focus on the zebrafish embryo but draw comparisons with other vertebrate model systems and refer to invertebrate models where informative.

Investigating relationships between biomarkers of exposure and environmental copper and manganese levels in house dusts from a Portuguese industrial city.

This study reports on data obtained from a pilot survey focusing on house dust and toenail metal(loids) concentrations in residents living in the industrial city of Estarreja. The study design hereby described aims at investigating relationships between human toenails and both copper and manganese levels in settled house dusts. A total of 21 households and 30 individuals were recruited for the pilot study: 19 households corresponding to 27 residents living near the industrial complex, forming the exposed group, plus 2 households and 3 residents from residential areas with no anticipated environmental contaminants that were used for comparison. Factorial analysis was used for source identification purposes. Investigation on the potential influence of environmental factors over copper and manganese levels in the toenails was carried out via questionnaire data and multiple correspondence analysis. The results show that copper concentrations are more elevated in the indoor dusts, while manganese concentrations are more elevated in the outdoor dust samples. The geometrical relationships in the datasets suggest that the backyard soil is a probable source of manganese to the indoor dust. Copper and manganese contents in the toenail clippings are more elevated in children than in adults, but the difference between the two age groups is not statistically significant (p > 0.05). Investigation of environmental factors influencing the exposure-biomarker association indicates a probable relationship between manganese contents in indoor dust and manganese levels in toenail clippings, a result that is partially supported by the bioaccessibility estimates. However, for copper, no relationship was found between indoor dusts and the biomarkers of exposure.

Geochemistry, mineralogy, solid-phase fractionation and oral bioaccessibility of lead in urban soils of Lisbon.

An urban survey of Lisbon, the largest city in Portugal, was carried out to investigate its environmental burden, emphasizing metallic elements and their public health impacts. This paper examines the geochemistry of lead (Pb) and its influence on human health data. A total of 51 soil samples were collected from urban recreational areas used by children to play outdoors. The semi-quantitative analysis of Pb was carried out by inductively coupled plasma mass spectrometry after an acid digestion. X-ray diffraction was used to characterize the soil mineralogy. The solid-phase distribution of Pb in the urban soils was investigated on a subset of 7 soils, out of a total of 51 samples, using a non-specific sequential extraction method coupled with chemometric analysis. Oral bioaccessibility measurements were obtained using the Unified BARGE Method developed by the Bioaccessibility Research Group of Europe. The objectives of the study are as follows: (1) investigation of Pb solid-phase distribution; (2) interpretation of Pb oral bioaccessibility measurements; (3) integration of metal geochemistry with human health data; and (4) understanding the influence of geochemistry and mineralogy on oral bioaccessibility. The results show that the bioaccessible fraction of Pb is lower when major metal fractions are associated with less soluble soil phases such as Fe oxyhydroxides, and more increased when the metal is in the highly soluble carbonate phase. However, there is some evidence that the proportion of carbonates in the soil environment is also a key control over the oral bioaccessibility of Pb, irrespective of its solid-phase fractionation.

Lead bioaccessibility in topsoils from lead mineralisation and urban domains, UK.

Predictive linear regression (LR) modelling indicates that total Pb is the only highly significant independent variable for estimating Pb bioaccessibility in "mineralisation domains" located in limestone (high pH) and partly peat covered (low pH) shale-sandstone terrains in England. Manganese is a significant minor predictor in the limestone terrain, whilst organic matter and sulphur explain 0.5% and 2% of the variance of bioaccessible Pb in the peat-shale-sandstone terrain, compared with 93% explained by total Pb. Bootstrap resampling shows that LR confidence limits overlap for the two mineralised terrains but the limestone terrain has a significantly lower bioaccessible Pb to total Pb slope than the urban domain. A comparison of the absolute values of stomach and combined stomach-intestine bioaccessibility provides some insight into the geochemical controls on bioaccessibility in the contrasting soil types.

Modelling lead bioaccessibility in urban topsoils based on data from Glasgow, London, Northampton and Swansea, UK.

Predictive linear regression (LR) modelling between bioaccessible Pb and a range of total elemental compositions and soil properties was executed for the Glasgow, London, Northampton and Swansea urban areas in order to assess the potential for developing a national urban bioaccessible Pb dataset for the UK. LR indicates that total Pb is the only highly significant independent variable for estimating the bioaccessibility of Pb. Bootstrap resampling shows that the relationship between total Pb and bioaccessible Pb is broadly the same in the four urban areas. The median bioaccessible fraction ranges from 38% in Northampton to 68% in London and Swansea. Results of this study can be used as part of a lines of evidence approach to localised risk assessment but should not be used to replace bioaccessibility testing at individual sites where local conditions may vary considerably from the broad overview presented in this study.

Anthropogenic and geogenic impacts on arsenic bioaccessibility in UK topsoils.

Predictive linear regression (LR) modelling between bioaccessible arsenic (B-As) and a range of total elemental compositions and soil properties was executed in order to assess the potential for developing a national B-As dataset for the UK. LR indicates that total arsenic (As) is the only highly significant independent variable for estimating B-As in urban areas where it explains 75-92% of the variance. The broad compatibility of the London, Glasgow and Swansea regression models suggests that application of these models to estimate bioaccessible As in UK soils impacted by diffuse anthropogenic urban contamination and non-ferrous metal processing should be relatively accurate. In areas dominated by Jurassic ironstones and associated clays and limestones, total As, P and pH are significant, accounting for 53, 14 and 5%, respectively, of the B-As variance. Models based on total As as the sole predictor in the combined Jurassic and Cretaceous sedimentary ironstones datasets explain about 40% of the B-As variance. The median As bioaccessible fraction (%As-BAF) is 19 to 28% in the anthropogenic contamination impacted urban domains, but much lower (5-9%) in geogenic terrains dominated by ironstones. Results of this study can be used as part of a lines of evidence approach to localised risk assessment but should not be used to replace bioaccessibility testing at individual sites where local conditions may vary considerably from the broad overview presented in this study.

Bioaccessibility of arsenic in soils developed over Jurassic ironstones in eastern England.

Jurassic ironstones outcropping over parts of eastern England give rise to soils with arsenic concentrations in excess of the UK soil guideline value of 20 mg kg(-1) for residential areas. Total arsenic concentrations were determined for 73 ironstone derived soils and bioaccessible arsenic determined using an in vitro physiologically based extraction test. The bioaccessible arsenic concentration for these soils was found to be well below the soil guideline value with a mean concentration of 4 mg kg(-1) and a range of 2-17 mg kg(-1). The bioaccessible fraction ranges from 1.2 to 33%. Data from a sequential extraction test based on the use of aqua regia as the main extractant is presented for a subset of 20 of the soils. Chemometric data reduction is used to demonstrate that the bioaccessible arsenic is mainly contained within calcium iron carbonate (sideritic) assemblages and only partially iron aluminosilicates, probably berthierine, and iron oxyhydroxide phases, probably goethite. It is suggested that the bulk of the non-bioaccessible arsenic is bound up with less reactive iron oxide phases.

Information presentation and decisions to enter clinical trials: a hypothetical trial of hormone replacement therapy.

We examined recruitment to an imaginary trial of hormone replacement therapy (HRT) following two different styles of information about HRT. We predicted that for treatments which, like HRT, are available outside a trial, people offered the facts as currently known would be less likely to remain unsure about the relative costs and benefits, and so less likely to agree to enter a randomised trial. In contrast, when the information provided reflected the current state of uncertainty which justified the trial, we predicted that people would be less likely to form a preference for one treatment arm over the other, and so more likely to agree to enter a trial. One hundred women aged 25-40 years were informed about HRT via a video and an information leaflet. For half the participants the information was framed in a way which emphasised the current state of uncertainty about the relative costs and benefits of HRT, and in that respect it reflected the justification for a trial. This version was considered to be similar in style to information commonly provided to potential trial participants. For half the participants the same information was framed in a way which offered explicit numerical detail about currently known facts, and in that respect it was considered to be similar in style to information commonly available to doctors prior to a trial. Women learned as much about HRT in the two conditions, but women given the explicit versions were more likely (i) to hold a stronger view about whether or not they would take HRT (ratings were not elicited from the first 30 participants in this condition. N = 20, p < 0.05 1 tailed) and (ii) to refuse entry to the trial (N = 50, p < 0.05 2 tailed). Those who, given the explicit version, agreed rather than refused to enter the trial, scored higher on believing that others control their health (p < 0.01 2 tailed).