The Ecological Impacts of Contaminated Sediment from Abandoned Metal Mines

Contains public sector information licensed under the Open Government Licence v3.0. The OGL requires that users acknowledge the information provider and/or source of the information with an attribution statement.Pollution from abandoned non-coal (i.e. metal) mines is a serious impediment to rivers meeting the water quality targets set out in River Basin Management Plans. Recent work has identified the mines most likely to be causing a significant environmental impact and hence where efforts to prevent pollution need to be focussed. Yet, it is not clear to what extent rivers, and the animal and plant life they support, are impacted by the legacy of past pollution still bound up in river sediments. Work will be undertaken to reduce toxic metals in mine waters before they enter the river. However, if riverbed sediments are already contaminated and affecting life in rivers, the planned clean-up of mine water sources may not result in recovery of ecological condition. A controlled laboratory experiment was undertaken where river invertebrates (mayfly larvae) from an uncontaminated site were incubated with contaminated riverbed sediment collected downstream of an abandoned metal mine. Concentrations of metals in the tissues of the mayflies increased over the duration of the incubation, particularly those metals that were in high concentrations in the sediment, i.e. cadmium, copper and zinc. As the sediment was the only substantial source of metals in the experiment, it is apparent that the contaminated riverbed sediment was acting as a source of bioavailable metals. It is likely that contaminated sediments, including riverbed sediment, will act as a source of bioavailable metals, at least to benthic organisms, even where mine drainage water is treated to reduce metal concentrations. Metal toxicity occurs when the rate of metal uptake into an organism exceeds the combined rates of excretion and physiological detoxification. Current tests of metal toxicity on biota typically do not match in scale (temporal, spatial and taxonomic range) with assessments of ecological quality undertaken for management, which raises questions regarding the adequacy of environmental limits based on laboratory testing. Existing data were compiled describing geochemistry of riverbed sediment and the Biological Quality Elements invertebrates, diatoms, macrophytes and fish, collected by the regulatory authorities to assess the condition of rivers. As toxic effects of trace metals were not expected at low concentrations, the biological response to sediment metal concentration was determined using a threshold model. Thresholds were found for biotic metrics based on species richness, but other metrics (diatom EQR, macrophyte EQR and invertebrate ASPT) displayed implausible positive relationships with sediment metal concentrations and should not be relied upon for classification of ecological status in waterbodies affected by mining. New data were collected from 20 spatially-independent river catchments in areas affected by metal mine facilities, including samples of the macroinvertebrate community, bioavailability of metals (assessed as metal concentrations in the body tissue of tolerant taxa), and sediment metal concentrations. There were strong correlations between sediment metal concentrations and measured bioavailability, particularly for copper and lead. Measurements of bioavailable metals were related to changes in taxon richness in the invertebrate samples. The data were used to develop a new biotic index (MetTol), which can be used to assess the extent of ecological damage from metal contamination using standard invertebrate monitoring data, and to construct dose response curves based on species sensitivities. A number of approaches were used to establish tolerable limits for sediment metal concentrations based on ecological data, and the results compared with existing Canadian sediment quality guidelines. The limits for copper derived from ecological data were most consistent with existing sediment guidelines. The limits for other metals (silver, arsenic, cadmium, nickel, lead and zinc) derived from ecological data were up to an order of magnitude above the Canadian interim sediment quality guidelines. These existing guidelines, based on toxicological data, may be too precautionary, and we suggest that guideline sediment concentrations based on ecological data may provide a more appropriate level of protection for the environment

Proximal humerus reconstruction after tumour resection: biological versus endoprosthetic reconstruction

The purpose of this study was to compare the outcome, complications and survival of the three most commonly used surgical reconstructions of the proximal humerus after transarticular tumour resection. Between 1985 and 2005, 38 consecutive proximal humeral reconstructions using allograft-prosthesis composite (n = 10), osteoarticular allograft (n = 13) or a modular tumour prosthesis (n = 14) were performed in our clinic. The mean follow-up was ten years (1–25). Of these, 27 were disease free at latest follow-up (mean 16.8 years) and ten had died of disease. The endoprosthetic group presented the smallest complication rate of 21% (n = 1), compared to 40% (n = 4) in the allograft-prosthesis composite and 62% (n = 8) in the osteoarticular allograft group. Only one revision was performed in the endoprosthetic group, in a case of shoulder instability. Infection after revision (n = 3), pseudoarthrosis (n = 2), fracture of the allograft (n = 3) and shoulder instability (n = 4) were the major complications of allograft use in general. Kaplan-Meier analysis showed a significantly better implant survival for the endoprosthetic group (log-rank p = 0.002). At final follow-up the Musculoskeletal Tumour Society scores were an average of 72% for the allograft-prosthetic composite (n = 7, median follow-up 17 years), 76% for the osteoarticular allograft (n = 3, 19 years) and 77% for the endoprosthetic reconstruction (n = 10, 5 years) groups. An endoprosthetic reconstruction after transarticular proximal humeral resection resulted in the lowest complication rate, highest implant survival and comparable functional results when compared to allograft-prosthesis composite and osteoarticular allograft use. We believe that the surgical approach that best preserves the abductor mechanism and provides sufficient surgical exposure for tumour resection contributed to better functional results and glenohumeral stability in the endoprosthetic group

A lactate shuttle system between tumour and stromal cells is associated with poor prognosis in prostate cancer

Background In a malignant tumour, cancer cells are embedded in stromal cells, namely cancer-associated fibroblasts (CAFs). These CAFs are now accepted as important players in cancer dynamics, being involved in tumour growth and progression. Although there are various reports on the interaction between tumour and stromal cells, the clinico-pathological significance of this cross-talk is still largely unknown. In this study, we aimed to characterise the expression of key metabolic proteins involved in glucose transport, pyruvate/lactate shuttle system, glycolytic metabolism and fatty acid oxidation in CAFs and tumour cells in different stages of malignant transformation. We further aimed to contextualise the clinico-pathological significance of these protein expression profiles with reference to known prognostic indicators, including biochemical recurrence in pT stage. Methods Prostate tissues were obtained from 480 patients with a median age of 64 years following radical prostatectomy with no previous hormonal therapy. Tissues were analysed for the expression of several key metabolism-related proteins in glands and surrounding fibroblasts by immunohistochemistry. Reliable markers of prognosis such as pT stage and biochemical recurrence were assessed for each case. Results We observed that prostate cancer cells did not rely mainly on glycolytic metabolism, while there was a high expression of MCT4 and CAIX - in CAFs. This corroborates the hypothesis of the "Reverse Warburg effect" in prostate cancer, in which fibroblasts are under oxidative stress and express CAIX, an established hypoxia marker. We found that alterations in the expression of metabolism-related proteins were already evident in the early stages of malignant transformation, suggesting the continuing alteration of CAFs from an early stage. Additionally, and for the first time, we show that cases showing high MCT4 expression in CAFs with concomitant strong MCT1 expression in prostate cancer (PCa) cells are associated with poor clinical outcome, namely pT3 stage of the tumour. Conclusions In summary, this work demonstrates for the first time the clinico-pathological significance of the lactate shuttle in prostate cancer. It also suggests that other alterations in CAFs may be useful prognostic factors, and further supports the use of MCT1/MCT4 as targets for PCa therapy.NPG received a fellowship from the Portuguese Foundation for Science and Technology (FCT), refs. SFRH/BD/61027/2009. This work was supported by the FCT grant ref. PTDC/SAUMET/113415/2009, under the scope of "Programa Operacional Tematico Factores de Competitividade" (COMPETE) of "Quadro Comunitario de Apoio III" and co-financed by Fundo Comunitario Europeu FEDER. JA was supported by a Boehringer Ingelheim Fonds fellowship

Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin

VanA-type resistance to glycopeptide antibiotics in clinical enterococci is regulated by the VanSARA two-component signal transduction system. The nature of the molecular ligand that is recognised by the VanSA sensory component has not hitherto been identified. Here we employ purified, intact and active VanSA membrane protein (henceforth referred to as VanS) in analytical ultracentrifugation experiments to study VanS oligomeric state and conformation in the absence and presence of vancomycin. A combination of sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge (SEDFIT, SEDFIT-MSTAR and MULTISIG analysis) showed that VanS in the absence of the ligand is almost entirely monomeric (molar mass M = 45.7 kDa) in dilute aqueous solution with a trace amount of high molar mass material (M ~ 200 kDa). The sedimentation coefficient s suggests the monomer adopts an extended conformation in aqueous solution with an equivalent aspect ratio of ~ (12+2). In the presence of vancomycin over a 33% increase in the sedimentation coefficient is observed with the appearance of additional higher s components, demonstrating an interaction, an observation consistent with our circular dichroism measurements. The two possible causes of this increase in s – either a ligand induced dimerization and/or compaction of the monomer are considered

Measurement of the Relative Branching Fraction of Υ(4S)\Upsilon(4S) to Charged and Neutral B-Meson Pairs

We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ -> J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+B-)/Gamma(Y(4S) -> B0\bar{B0}) = = 1.04 +/- 0.07(stat) +/- 0.04(syst). With the assumption that f+- + f00 = 1, we obtain f00 = 0.49 +/- 0.02(stat) +/- 0.01(syst) and f+- = 0.51 +/- 0.02(stat) +/- 0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Y(4S) resonance.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

First Observation of the Decays B0→D∗−ppˉπ+B^{0}\to D^{*-}p\bar{p}\pi^{+} and B^{0}\to D^{*-}p\bar{n}$

We report the first observation of exclusive decays of the type B to D^* N anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton \pi^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-} proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Study of the Decays B0 --> D(*)+D(*)-

The decays B0 --> D*+D*-, B0 --> D*+D- and B0 --> D+D- are studied in 9.7 million Y(4S) --> BBbar decays accumulated with the CLEO detector. We determine Br(B0 --> D*+D*-) = (9.9+4.2-3.3+-1.2)e-4 and limit Br(B0 --> D*+D-) < 6.3e-4 and Br(B0 --> D+D-) < 9.4e-4 at 90% confidence level (CL). We also perform the first angular analysis of the B0 --> D*+D*- decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% CL. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays.Comment: 21 pages, 5 figures, submitted to Phys. Rev.

A Search for B→τνB\to \tau\nu

We report results of a search for $B\to\tau\nu$ in a sample of 9.7 million charged $B$ meson decays. The search uses both $\pi\nu$ and $\ell\nu\bar\nu$ decay modes of the $\tau$, and demands exclusive reconstruction of the companion $\bar B$ decay to suppress background. We set an upper limit on the branching fraction ${\cal B}(B\to \tau\nu) < 8.4\times 10^{-4}$ at 90% confidence level. With slight modification to the analysis we also establish ${\cal B}(B^\pm\to K^\pm\nu\bar\nu) < 2.4\times 10^{-4}$ at 90% confidence level.Comment: 10 ages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurements of B --> D_s^{(*)+} D^{*(*)} Branching Fractions

This article describes improved measurements by CLEO of the $B^0 \to D_s^+ D^{*-}$ and $B^0 \to D_s^{*+} D^{*-}$ branching fractions, and first evidence for the decay $B^+ \to D_s^{(*)+} \bar{D}^{**0}$, where $\bar{D}^{**0}$ represents the sum of the $\bar{D}_1(2420)^0$, $\bar{D}_2^*(2460)^0$, and $\bar{D}_1(j=1/2)^0$ L=1 charm meson states. Also reported is the first measurement of the $D_s^{*+}$ polarization in the decay $B^0 \to D_s^{*+} D^{*-}$. A partial reconstruction technique, employing only the fully reconstructed $D_s^+$ and slow pion $\pi_s^-$ from the $D^{*-} \to \bar{D}^0 \pi^-_s$ decay, enhances sensitivity. The observed branching fractions are ${\mathcal B} (B^0 \to D_s^+ D^{*-}) = (1.10 \pm 0.18 \pm 0.10 \pm 0.28)$, ${\mathcal B} (B^0 \to D_s^{*+} D^{*-}) = (1.82 \pm 0.37 \pm 0.24 \pm 0.46)$, and ${\mathcal B} (B^+ \to D_s^{(*)+} \bar{D}^{**0}) = (2.73 \pm 0.78 \pm 0.48 \pm 0.68)$, where the first error is statistical, the second systematic, and the third is due to the uncertainty in the $D_s^+ \to \phi \pi^+$ branching fraction. The measured $D_s^{*+}$ longitudinal polarization, $\Gamma_L/\Gamma = (50.6 \pm 13.9 \pm 3.6)$, is consistent with the factorization prediction of 54%.Comment: 26 pages (LaTeX), 15 figures. To be submitted to PR