Trade-offs and synergies in the ecosystem service demand of urban brownfield stakeholders

Brownfield site redevelopment presents an opportunity to create urban green spaces that provide a wide range of ecosystem services. It is important, therefore, to understand which ecosystem services are demanded by stakeholders and whether there are trade-offs or synergies in this demand. We performed a quantitative survey of ecosystem service demand from brownfield sites that included all major stakeholder groups. Results showed that there was a strong trade-off between demand for services related to property development (e.g. ground strength and low flood risk) and all other services, which were linked to vegetated sites. There was a secondary, but weak, trade-off between demand for services of more ‘natural’ vegetated sites (e.g. with a biodiversity protection role) and those linked to aesthetics and recreation. Stakeholders with a strong preference for biodiversity protection formed a distinct group in their ecosystem service demands. While a ‘development’ vs ‘green space’ trade-off may be unavoidable, the general lack of strong trade-offs in demand for other services indicated that the creation of multifunctional greenspaces from former brownfield sites would be desirable to most stakeholders, as long as these are biophysically possible

FGF23 metabolism, a new paradigm for chronic kidney disease

Introduction:  Fibroblast growth factor-23 (FGF23) is a major regulator of phosphate metabolism often elevated in genetic hypophosphataemic disorders and in chronic kidney disease. Recent studies have identified relationships between FGF23 and various markers of iron status including ferritin. New assays measuring the intact form of FGF23 have been released.  Objective:  To determine the relationship between ferritin and C-terminal and intact FGF23 concentrations in blood.  Method:  FGF23 concentrations were measured using the 2nd generation, two-site enzyme-linked immunosorbent assay for either C-terminal or intact FGF23 (Immutopics Inc., Ca, USA). Ferritin was measured on a COBAS 6000 (Roche Diagnostics). Assay accuracy and precision were monitored using kit controls supplied by the manufacturers.  Results:  We observe a weak negative correlation between measurements of C-terminal and intact FGF23 (Pearson’s rho=0.85 p<0.0001). We observed no statistically significant correlation of ferritin concentrations with either FGF23 C-terminal or intact. However high concentrations of ferritin were observed in samples showing low concentrations of C-terminal FGF23 (<140RU/mL) and intact FGF23 (<122pg/mL).  Conclusion:  Although not statistically significant, we observe a negative relationship between concentrations of ferritin and FGF23. High level of C-terminal FGF23 is found in patients with chronic kidney disease, especially in patients with end-stage renal disease usually regarded as a compensatory response to hyperphosphatemia or phosphate overload. We observed a cluster of patients with retention of both C-terminal and intact FGF23 associated with low levels of ferritin suggesting that metabolism and/or excretion of FGF23 in CDK patients might be an iron dependent mechanism

How accurate is your sclerostin measurement?:Comparison between three commercially available sclerostin ELISA kits

Sclerostin, bone formation antagonist is in the spotlight as a potential biomarker for diseases presenting with associated bone disorders such as chronic kidney disease (CDK-MBD). Accurate measurement of sclerostin is therefore important. Several immunoassays are available to measure sclerostin in serum and plasma. We compared the performance of three commercial ELISA kits. We measured sclerostin concentrations in serum and EDTA plasma obtained from healthy young (18-26 years) human subjects using kits from Biomedica, TECOmedical and from R&D Systems. The circulating sclerostin concentrations were systematically higher when measured with the Biomedica assay (serum: 35.5 ± 1.1 pmol/L; EDTA: 39.4 ± 2.0 pmol/L; mean ± SD) as compared with TECOmedical (serum: 21.8 ± 0.7 pmol/L; EDTA: 27.2 ± 1.3 pmol/L) and R&D Systems (serum: 7.6 ± 0.3 pmol/L; EDTA: 30.9 ± 1.5 pmol/L). We found a good correlation between the assay for EDTA plasma (r > 0.6; p < 0.001) while in serum, only measurements obtained using TECOmedical and R&D Systems assays correlated significantly (r = 0.78; p < 0.001). There was no correlation between matrices results when using the Biomedica kit (r = 0.20). The variability in values generated from Biomedica, R&D Systems and TECOmedical assays raises questions regarding the accuracy and specificity of the assays. Direct comparison of studies using different kits is not possible and great care should be given to measurement of sclerostin, with traceability of reagents. Standardization with appropriate material is required before different sclerostin assays can be introduced in clinical practice

How accurate is your sclerostin measurement? Comparison between two commercially available sclerostin ELISA kits.

Introduction: Sclerostin (SOST), osteocyte-secreted soluble antagonist of the Wnt/β-catenin signaling pathway, is a potent inhibitor of osteoblastogenesis. Circulating SOST levels have been measured in a plethora of disorders such as ankylosing spondylitis, chronic kidney disease, diabetes, fractures, hypercortisolism, multiple myeloma and spinal cord injury. SOST is a crucial regulator of the skeletal anabolic action of PTH and as so, anti-sclerostin antibodies are being investigated as potential therapeutic molecules for metabolic bone diseases. Accurate measurement of SOST is therefore of utmost importance for the diagnosis of bone disorders and therapy effectiveness. However, reports so far suggests further study is needed before SOST measurements are introduced into routine clinical practice. Objective: To compare two commercially available assays for measurement of circulating SOST. Method: EDTA-plasma samples from 36 anonymised healthy individuals were analyzed using ELISA kit for circulating SOST from Biomedica (Vienna, Austria) and TecoMedical (TECO, Sissach, Switzerland). Both assays are based on immuno-capture using two antibodies which have been raised against human recombinant SOST and are highly specific for this molecule. Results: Circulating SOST levels in EDTA plasma samples were found to be significantly different between TECO and Biomedica assays (36.9 ± 2 and 21.3 ± 1pmol/L, respectively, p<0.001) with discrepancies of up to 32pmol/L. The TECO assay demonstrated less variability between duplicates (2.6±2.4 % and 7.4±6.3 % respectively) and dilution study showed that the biomedical kit over-recovered diluted samples by up to 60%. When samples containing various concentrations of endogenous sclerostin were spiked with a known amount of SOST, recovery was 88.5% and 104% respectively. Conclusion: The variability in values generated from Biomedica and TECO assays has raised questions regarding the specificity of antibodies used by the two manufactures, and whether there is possible interference affecting one of the assays remains unclear. Cross-reactivity experiments are being conducted to determine the source of variation between the two kits. Until such issues are resolved, measurement of sclerostin remains invaluable for understanding the mechanism by which osteocytes regulate bone turnover but should be used in discretion and interpretation should be carried out with guided clinical evidence

Assessment of C3-Epi-25-Hydroxyvitamin D concentration in adult serum: LC-MS/MS determination using [2H3] 3-epi-25OHD3 internal standard and NIST traceable commercial 3-epi-25OHD calibrators.

Background: The C-3 Epimer of 25 Hydroxyvitamin D3 (3-Epi-25OHD3) is produced in the liver by the epimerisation pathway of 25-hydroxy vitamin D3. It differs from 25OHD3 in configuration of the hydroxyl group at the third carbon (C-3) position. Despite the fact that little is known regarding its clinical significance, concerns have been raised that isobaric interference may result in over-estimation of total 25OHD when measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). Objective: The aim of the study was to assess the occurrence of 3-Epi-25OHD3 in adult serum samples. A LC-MS/MS technique was developed to resolve and quantify 3-Epi-25OHD3 from 25OHD3. The newly available NIST (SRM972a) traceable 3-Epi-25OHD commercial standards were used to ensure assay accuracy. Method: Serum was precipitated with zinc sulphate and acetonitrile containing [2H3]-3-epi-25OHD3 as internal standard. The extract was chromatographed using a 2.6µm 100 x 2.1mm I.D. solid core particle column. Mass detection and quantification were performed by positive electrospray ionization with MS/MS in multiple reaction monitoring mode. Results: The method was able to fully resolved 3-Epi-25OHD3 from 25OHD3. The intraassay CVs for the epimer were 6.3% and 4.1% at 25.4 and 62.1 nmol/L respectively; and interassay CVs were 8.3% and 6.5% at 27.6 and 63.2 nmol/L, respectively. In our sample cohort with 25OHD3 ranged between 3.4 – 165 nmol/L, 3-Epi-25OHD3 was detected in 91.9% of samples (mean = 3.8 nmol/L). No detectable 3-Epi-25OHD2 was found in our sample study. One patient sample had total 25OHD3 of 187 nmol/L that was shown to contain 141 nmol/L of 25OHD3 and 44 nmol/L of 3-Epi-25OHD3. This patient was receiving a high dose of vitamin D supplementation. Conclusion: Using [2H3]-3-epi-25OHD3 as internal standard and NIST aligned calibrators enabled us to obtain an accurate assessment of 3-epi-25OHD concentration in adult serum. Although the concentration of serum 3-epi-25OHD3 was found to be low the presence was observed in the majority of our samples. The findings in this study showed that 3-epi-25OHD3 contributed to the overestimation of 25OHD3 that could potentially resulted in misinterpretation of total vitamin D status

Circulating α-Klotho Levels Are Inversely Correlated to FGF-23 in Tumour Induced Osteomalacia

Tumour induced osteomalacia is characterised by high circulating levels of fibroblast growth factor 23 (FGF23) due to ectopic secretion from mesenchymal tumors. An abundance of FGF23 drives the hypophosphatemia and low 1,25-dihydroxy vitamin D levels characteristic of this condition. The single-pass trans-membrane protein α-klotho is integral for FGF23-mediated receptor activation and its downstream effects. In addition, α-klotho may have a phosphaturic effect independent of FGF-23. The regulation of α-klotho in the face of high circulating FGF23 is currently unknown. We investigated the relationship between circulating FGF23 and α-klotho in patients with TIO. We identified 15 consecutive plasma FGF-23 requests in subjects with confirmed TIO for testing. FGF-23 was measured using Immutopics C-term ELISA kit and soluble α-klotho was measured using the IBL ELISA kit. The group consisted of 7 males and 8 females with an age of 53 ± 20 years (mean ± SD). Only one subject was not on treatment for TIO at the time of sampling. The average circulating levels of FGF23 and α-klotho were 286 ± 244 RU/ml and 644 ± 309 pg/ml respectively. There was an inverse correlation between FGF-23 and α-klotho (Pearson coefficient - 0.28). This inverse correlation may suggest that increasing levels of FGF23 in TIO down-regulate α-klotho expression in the kidney and parathyroid glands leading to reduced circulating levels of α-klotho. Given α-klotho’s role in mediating FGF23 signalling and that α-klotho may be a phosphaturic factor in its own right; such an adaptive mechanism would help partially reduce the renal phosphate wasting seen in TIO. In summary there is an inverse correlation seen between circulating levels of FGF23 and α-klotho in TIO. This may suggest there is a down-regulation of α-klotho expression to limit the phosphate wasting and resultant hypophosphatemia that is seen in TIO

Development and Validation of a LC-MS/MS Assay for Quantification of Parathyroid Hormone (PTH 1-34) in human Plasma

Background: Teriparatide [recombinant human PTH (1-34)] is an osteoanabolic agent for treatment of osteoporosis. The effect on bone decreases the risk of vertebral and non-vertebral fractures and increases bone mineral density (BMD) in post-menopausal women with osteoporosis. Measurement of PTH (1-34) is valuable in assessing treatment response and concordance with therapy.Aim: To develop and validate a method for quantification of PTH (1-34) using Liquid chromatography tandem mass spectrometry (LC-MS/MS) and to perform comparison with a commercial immunoassay.  Method: Sample extraction was developed using a Waters (Milford, MA, USA) Oasis® HLB µElution solid phase extraction. Quantification m/z transition 589>656 was used on Waters/Micromass® Quattro Ultima™ Pt mass spectrometer to measure PTH (1-34) in human plasma using rat PTH (1-34) as internal standard. Validation criteria were carried out against industry standards. PTH (1-34) results obtained from human subjects given Teriparatide (Fortsteo, Eli Lilly, IN, USA) (n=390) were compared against results obtained from an immunoassay (IDS; Boldon Tyne and Wear. UK).  Results and Discussion: LC-MS/MS produced a linear calibration curve from 10 to 2000 pg/mL (r2 >0.990). The LLoQ and LLoD for PTH (1-34) were 10 pg/mL and 2.1 pg/mL respectively. The inter- /intra-assay precision (CV%) of the method were 98.3% for four QCs (20, 100, 200, and 800 pg/mL). The mean recovery of PTH (1-34) was 107.2%. Method comparison between the LC-MS/MS and immunoassay using human EDTA plasma samples showed a high correlation (r2 = 0.950). A concentration-dependent, negative bias of 35.5% was observed across the range of 0 – 800 pg/mL. The immunoassay showed a 7% cross reactivity to human PTH (1-84) and 44% to rat PTH (1-34), no interference was observed in the LC-MS/MS method. Matrix effect and cross reactivity to human PTH (1-84) in the immunoassay were the likely contributing factors to the bias between the methods. The oxidised form of PTH (1-34) does not interfere with our LC-MS/MS method.  Conclusion: Our LC-MS/MS method demonstrated linearity over the calibration range, good precision and accuracy, excellent analyte recovery, and negligible matrix effects. The method was successfully used for measurements of PTH (1-34) in rat and human plasma

Measurement of autoantibodies against osteoprotegerin in adult human serum: development of a novel ELISA assay

Introduction: In 2009, neutralizing autoantibodies against OPG (α-OPGAb) blocking the inhibitory effect of OPG on RANK signaling pathway were identified in a man with celiac disease associated with severe osteoporosis. Although this finding was not reproduced in thirty patients presenting coeliac disease and low bone mineral density, Hauser et al (2013) recently detected the presence of α-OPGAb in patients presenting Rheumatoid Arthritis, Systemic Lupus Erythematosus, Spondyloarthritis and Osteoporosis. There is a growing focus on OPG autoantibodies as primary cause of high bone turnover in disorders with unknown etiology. Objective: To develop an enzyme linked immunosorbent assay (ELISA) for detection and quantification of α-OPGAb in patient serum samples. Method: A full-length human recombinant OPG is immobilized on a plate to allow capture of the antibodies from the sera. In a two-step reaction, the αOPGAb is detected using a biotinylated antibody and a horseradish peroxidase-labelled streptavidin. Substrate is incubated in a timed reaction and color development measured in a spectrophotometric microtiter plate reader. The concentration of human α-OPGAb in the samples is determined directly from a 4PL-fit standard curve. Results: Intra-assay imprecision was <5% at 274.4 ± 18.8 and 98.5 ± 2.9 ng/mL. Inter-assay imprecision was <20% at 324.2 ± 53.3 and 166.8 ± 30.6 ng/mL. Linear range was 0-500ng/mL. Lower and upper limit of quantification were 3.9 and 500 ng/mL. Cross reactivity was assessed against human sera containing raised thyroid antibody and RANKL to ensure assay specificity. Using the method presented, we established that the adult population would be considered positive with a titer above the cut-off limit (95%) of 68ng/mL. Our preliminary data suggested that 14% of our sample population (n=136) presented elevated α-OPGAb. Conclusion: We presented a novel ELISA assay for the detection and measurement of anti-OPG autoantibodies in human serum. The validated method showed excellent assay characteristics and is suitable for use in research and clinical hospital laboratories. In patients with severe form of osteoporosis, measurement of OPG autoantibodies could help clinicians identify appropriate treatment options for this particular subgroup of patients

W.G. Grace: Sporting Superstar, Cultural Celebrity, and Hero (to Oscar Wilde’s Villain) of the Great Public Drama of 1895

Abstract: »W.G. Grace: Sportstar, kulturelle Berühmtheit und Held (als Oscar Wildes Schurke) vom großen öffentlichen Drama von 1895«. This article explores the sporting superstardom and cultural celebrity of the Victorian English cricketer Dr. W.G. Grace, who played first-class cricket from 1865-1908. The great attention capital and significant masculine social status associated with his fame were deployed by him and the Marylebone Cricket Club (MCC) to side line the then dominant professional cricket teams and ensure that the aristocratic amateur-led MCC controlled the game from the early 1870s. It focuses on the social and cultural organisation of fame and a close analysis of Grace’s recognition to explore how Grace’s three-decade (1865-1895) superstardom and celebrity allied to a resurgence in his cricket form made Grace the masculine robust hero of 1895 to Oscar Wilde’s scandalous villain. It explores how that comparison played out as a public drama involving other celebrities. Wilde was reported as systematically removed from masculine social status and Grace approvingly confirmed in its secure embodiment and possession. Keywords: Cultural celebrity; attention capital; masculine social status; mediated publicness; public drama