Concentrations of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and one metalloid (As) as well as various parameters (pH, organic carbon, granulometric analysis and cation exchange capacity) ...were analyzed in 77 soil samples collected in the mining areas of La Zanja and Colquirrumi (Department of Cajamarca) and Julcani (Department of Huancavelica). Our study proposed geochemical baseline values for heavy metals in a natural region (La Zanja) from samples collected during the period of the environmental impact study (2006), that is, from an earlier period which occurred at the beginning of the exploitation of the current gold mine. The baseline values obtained were as follows: 8.26 mg kg-1 for Cr; 56.97 mg kg-1 for Ni; 22, 20 mg kg-1 for the Cu; 47.42 mg kg-1 for Zn; 27.50 mg kg-1 for As; 4.36 mg kg-1 for Cd; 4.89 mg kg-1 for Hg, and 44.87 mg kg-1 for Pb. Through the use of different indices of heavy metal contamination (geo-accumulation index (Igeo), improved Nemerow index (IIN) and potential ecological risk index (RI)), the degree of pollution caused by mining activities in two areas, Colquirrumi and Julcani, which have a high density of mining sites in operation, was determined. The values obtained from these indices indicated that the Colquirrumi region was the most contaminated, followed by Julcani. The area of La Zanja, despite being free of mining operations, presented slight diffuse pollution. Several positive correlations were obtained, with a high level of significance, between pH, organic carbon content, cation exchange capacity, and the Cr, Pb and Ni concentrations of the soils. The spatial distribution of the heavy metals was realized by means of the interpolation method of ordinary kriging. The results obtained and the experience gained in this work were necessary to facilitate the identification of soil contamination processes in high altitude areas of the Andes Western Cordillera (Peru) as a basis for taking appropriate measures when restoring soils, during mine closure processes, and to protect the quality of soil resources.
The environmental quality of soil in the central part of the Northern Plateau of Spain has been analyzed by studying the heavy metal content of 166 samples belonging to the horizons A, B and C of 89 ...soil profiles. The analysis to assess the environmental risk of heavy metals in the soil was carried out by means of the spatial distribution of nine heavy metals and the use of several pollution indices. The results showed that the concentration values of heavy metals (x ± S) in the superficial soil horizons were the following: With a total of 6.71 ± 3.51 mg kg -1, the contents of Cd is 0.08 ± 0.06 mg kg-1, Co is 6.49 ± 3.21 mg kg-1, Cu is 17.19 ± 10.69 mg kg-1, Cr is 18.68 ± 12.28 mg kg-1, Hg is 0.083 ± 0.063 mg kg-1, Ni is 12.05 ± 6.76 mg kg-1, Pb is 14.10 ± 11.32 mg kg-1 and Zn is 35.31 ± 14.63 mg kg-1. These nine metals exceed the values of the natural geological background level of Tertiary period sediments and rocks that form part of the Northern Plateau in Spain. Nemerow and Potential Ecological Risk indices were calculated, with the "improved" Nemerow index allowing pollution within the soil superficial horizons to be determined. The data obtained indicated that the majority of the soil (54.61%) showed low to moderate contamination, 22.31% showed moderate contamination and 21.54% of the samples were not contaminated. If we consider the Potential of Ecological Risk Index (RI), the largest percentage of soil samples showed low (70.79%) to moderate (25.38%) ecological risk of potential contamination, where the rest of the soil presented a considerable risk of contamination. The nine trace elements were divided into three principal components: PC1 (Cu, Cr, Ni, Co and Zn), PC2 (As and Hg) and PC3 (Cd). All metals accumulated in the soil came from parent rock, agricultural practices and the run-off of residual waters towards rivers and streams caused by industrial development and an increase in population density. Finally, cartography of the spatial distribution of the heavy metal contents in the soil of the Northern Plateau of Spain was generated using Kriging interpolation methods. Furthermore, the total heavy metal contents in three soil orders present in the area, namely Entisols, Inceptisols, and Alfisols, were analyzed. Other soil parameters, such as the organic matter content, pH, clay content and cation exchange capacity, was measured to determine their influence on and correlation with the heavy metal contents.
Nowadays, soil erosion is a global problem of great environmental and social concern, affecting natural resources, natural spaces and agricultural production. Therefore, it is necessary to carry out ...an erosion risk analysis to estimate the amount of soil lost, as well as to establish possible conservation practices to mitigate this loss. One way of doing this is through the integration of empirical equations such as RUSLE and GIS techniques, giving rise to a mapping of potential and actual erosion, considering the factors that make up this equation. The results obtained indicate that the areas with extreme erosion levels in Arribes del Duero, that is, with the greatest losses (greater than 200 Tm/ha/year), correspond to areas with steep slopes, poorly developed soils such as Leptosols and Regosols and vegetation with little or no vegetation cover. On the other hand, areas with stable levels of erosion (up to 10 Tm/ha/year) are found in flat areas, with more developed soils, such as Alisols and Luvisols, and vegetation with a higher density and herbaceous cover. Finally, it is concluded that the integration of GIS techniques with parametric equations constitutes a simple and economic tool for estimating these losses and, together with land use, allows different mitigation measures to be established, which, in our study area, focus on reducing the length and gradient of the slope, such as contour cultivation, construction of terraces and “bancales”.
Aims
Carbon accumulation in terrestrial ecosystems is inherent to the vegetation development and ageing process. Primary productivity synthetize biomass which is constantly incorporated to soil. ...Vegetation community composition, and other ecological drivers, are known to mediate biomass production. However, links between forest developmental stage and ecological drivers of carbon stocks are unexplored. We address this topic under the prediction that species-rich and uneven-sized forests can improve carbon storage potential in biomass and topsoil fraction across its development.
Methods
The study was carried in forest stands growing under Mediterranean conditions in Central Spain. Carbon content in both above- and below-ground tree biomass and in topsoil organic matter (0–40 cm) was measured in 30 sampling plots of variable size (900–3000 m
2
). We also assessed Shannon species diversity index, Gini tree-size inequality index and forest developmental stage using dendrochronological procedures to derive the mean age of the oldest trees. First-order interaction terms between diversity factors and forest age were regressed against carbon density in compartment-independent regressions.
Results
Forest-age and tree-size heterogeneity coupling was the main factor driving carbon density of both compartments. The interaction showed that woodlands maximize density in aged forests composed by uneven-sized trees. Models gave not support to consider species diversity as a mediator of carbon stocks.
Conclusion
Our results shed light on how tree-size heterogeneity can regulate the temporal dimension of forest ageing to rise the carbon storage potential. Mature forests in semi-arid environments cannot store carbon due to their intrinsic ontogeny, they need to grow structurally diverse.
While determining the uranium concentration in the rock (background level) and soils on the Iberian Massif of western Spain, several geochemical anomalies were observed. The uranium concentration was ...much higher than the geochemical levels at these locations, and several uranium minerals were detected. The proposed uranium background levels for natural soils in the west of Salamanca Province (Spain) are 29.8 mg kg−1 in granitic rock and 71.2 mg kg−1 in slate. However, the soil near the tailings of abandoned mines exhibited much higher concentrations, between 207.2 and 542.4 mg kg−1.
The calculation of different pollution indexes (Pollution Factor and Geo-accumulation Index), which reveal the conditions in the superficial horizons of the natural soils, indicated that a good percentage of the studied samples (16.7–56.5%) are moderately contaminated. The spatial distribution of the uranium content in natural soils was analysed by applying the inverse distance weighted method.
The distribution of uranium through the horizons of the soils shows a tendency to accumulate in the horizons with the highest clay content. The leaching of uranium from the upper horizons and accumulation in the lower horizons of the soil could be considered a process for natural attenuation of the surface impacts of this radiogenic element in the environment. Environmental restoration is proposed in the areas close to the abandoned mining facilities of this region, given the high concentration of uranium. First, all the tailings and other mining waste would be covered with a layer of impermeable material to prevent leaching by runoff. Then, a layer of topsoil with organic amendments would be added, followed by revegetation with herbaceous plants to prevent surface erosion.
Display omitted
•Uranium geochemical anomaly compared to the world geochemical background level.•Natural soils with diffuse pollution by mining activities.•The geochemical baseline of uranium in soils is greater on slates than on granites.•The vertical distribution of uranium in soil is concentrated in subsurface horizons.
Aims
We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by
Quercus suber
in its lower limits of rainfall and temperature. Two hypotheses were ...established: (1) regeneration of
Quercus
species is strongly favored by the presence of tree cover; and (2) growth of
Q. suber
is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge.
Methods
We selected woodlands and old fields with and without tree remnants (
n
= 3 per type), and analyzed stand structure, soil parameters and tree growth.
Results
Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in
Quercus
recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September.
Conclusions
Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of
Q. suber
where
Q. ilex
is increasing in abundance. Although temperature has a positive effect on the tree growth of
Q. suber
, when demographic processes are considered, decreases in water availability likely play a critical role in
Q. ilex
recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.
Trastuzumab-emtansine (T-DM1) is a standard treatment in advanced HER2-positive breast cancer. However, resistance inevitably occurs. We aimed to identify mechanisms of acquired T-DM1 resistance.
...HER2-positive breast cancer cells (HCC1954, HCC1419, SKBR3, and BT474) were treated in a pulse-fashion with T-DM1 to induce a resistant phenotype. Cellular and molecular effects of T-DM1 in parental versus resistant cells were compared. CDK1 kinase activity and cyclin B1 expression were assayed under various conditions. Genetic modifications to up- or downregulate
were conducted. Effects of T-DM1 on cyclin B1 levels, proliferation, and apoptosis were assayed in human
-positive breast cancer explants.
We obtained three cell lines with different levels of acquired T-DM1 resistance (HCC1954/TDR, HCC1419/TDR, and SKBR3/TDR cells). HER2 remained amplified in the resistant cells. Binding to HER2 and intracellular uptake of T-DM1 were maintained in resistant cells. T-DM1 induced cyclin B1 accumulation in sensitive but not resistant cells.
knockdown by siRNA in parental cells induced T-DM1 resistance, while increased levels of cyclin B1 by silencing
partially sensitized resistant cells. In a series of 18 HER2-positive breast cancer fresh explants, T-DM1 effects on proliferation and apoptosis paralleled cyclin B1 accumulation.
Defective cyclin B1 induction by T-DM1 mediates acquired resistance in HER2-positive breast cancer cells. These results support the testing of cyclin B1 induction upon T-DM1 treatment as a pharmacodynamic predictor in HER2-positive breast cancer.
.
A subset of HER2+ breast cancer patients manifest clinical resistance to trastuzumab. Recently, miR-26a and miR-30b have been identified as trastuzumab response regulators, and their target gene ...CCNE2 seems to play an important role in resistance to trastuzumab therapy. Cell viability was evaluated in trastuzumab treated HER2+ BT474 wt (sensitive), BT474r (acquired resistance), HCC1954 (innate resistance), and MDA-MB-231 (HER2-) cell lines, and the expression of miR-26a, miR-30b, and their target genes was measured. BT474 wt cell viability decreased by 60% and miR-26a and miR-30b were significantly overexpressed (~3-fold, p = 0.003 and p = 0.002, respectively) after trastuzumab treatment, but no differences were observed in resistant and control cell lines. Overexpression of miR-30b sensitized BT474r cells to trastuzumab (p = 0.01) and CCNE2, was significantly overexpressed after trastuzumab treatment in BT474r cells (p = 0.032), but no significant changes were observed in sensitive cell line. When CCNE2 was silenced BT474r cell sensitivity to trastuzumab increased (p = 0.03). Thus, the molecular mechanism of trastuzumab action in BT474 cell line may be regulated by miR-26a and miR-30b and CCNE2 overexpression might play an important role in acquired trastuzumab resistance in HER2+ breast cancer given that resistance was diminished when CCNE2 was silenced.
Both recessive and dominant genetic forms of Parkinson's disease have been described. The aim of this study was to assess the contribution of several genes to the pathophysiology of early onset ...Parkinson's disease in a cohort from central Spain.
We analyzed a cohort of 117 unrelated patients with early onset Parkinson's disease using a pipeline, based on a combination of a next-generation sequencing panel of 17 genes previously related with Parkinson's disease and other Parkinsonisms and CNV screening.
Twenty-six patients (22.22%) carried likely pathogenic variants in PARK2, LRRK2, PINK1, or GBA. The gene most frequently mutated was PARK2, and p.Asn52Metfs*29 was the most common variation in this gene. Pathogenic variants were not observed in genes SNCA, FBXO7, PARK7, HTRA2, DNAJC6, PLA2G6, and UCHL1. Co-occurrence of pathogenic variants involving two genes was observed in ATP13A2 and PARK2 genes, as well as LRRK2 and GIGYF2 genes.
Our results contribute to the understanding of the genetic architecture associated with early onset Parkinson's disease, showing both PARK2 and LRRK2 play an important role in Spanish Parkinson's disease patients. Rare variants in ATP13A2 and GIGYF2 may contribute to PD risk. However, a large proportion of genetic components remains unknown. This study might contribute to genetic diagnosis and counseling for families with early onset Parkinson's disease.
It has been proposed that a mild form of acquired resistance to thyroid hormone may occur in the general population. Its clinical significance remains largely unknown. The objective of the study was ...to explore whether a newly described thyroid hormone resistance index is associated with the risk of mortality in a sample of community-dwelling euthyroid subjects representative of the adult population of Spain.
Longitudinal observational study including 3750 individuals, free of thyroid disease, TPO antibodies-negative (<50 IU/mL) and with TSH levels within the euthyroid range (≥0.5 and ≤5.0 mUI/mL) participating in the nationwide study Di@bet.es (2008-2010).
We used the Thyroid Feedback Quantile-based Index (TFQI) as a marker of resistance to thyroid hormone. The study population was grouped into categories according to their TFQI values at baseline. Fatal events were ascertained from the national death registry (end of follow-up December 2016).
A total of 231 deaths were recorded during an average follow-up of 7.3 years. Compared with the category with the highest sensitivity to free thyroxine (TFQI ≤ p5) (reference), the relative risk of mortality in the categories with TFQI > p5 and ≤p25; >p25 and ≤p50; >p50 and ≤p75; >p75 and ≤p95 and >p95 were 1.01, (0.47-2.19), 1.42 (0.68-2.97), 1.54 (0.74-3.22), 1.47 (0.70-3.11) and 2.61 (1.16-5.89), respectively (P for trend 0.003). The association remained significant after multivariate adjustment of the data (P for trend 0.017).
A thyroid hormone resistance index focused on deviations of the average pituitary response to thyroid hormones may be associated with all-cause mortality independently of other conventional risk factors and comorbidities.
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