Accuracy of methods for reporting inorganic element concentrations and radioactivity in oil and gas wastewaters from the Appalachian Basin, U.S. based on an inter-laboratory comparison.

Accurate and precise analyses of oil and gas (O&G) wastewaters and solids (e.g., sediments and sludge) are important for the regulatory monitoring of O&G development and tracing potential O&G contamination in the environment. In this study, 15 laboratories participated in an inter-laboratory comparison on the chemical characterization of three O&G wastewaters from the Appalachian Basin and four solids impacted by O&G development, with the goal of evaluating the quality of data and the accuracy of measurements for various analytes of concern. Using a variety of different methods, analytes in the wastewaters with high concentrations (i.e., >5 mg L-1) were easily detectable with relatively high accuracy, often within ±10% of the most probable value (MPV). In contrast, often less than 7 of the 15 labs were able to report detectable trace metal(loid) concentrations (i.e., Cr, Ni, Cu, Zn, As, and Pb) with accuracies of approximately ±40%. Despite most labs using inductively coupled plasma mass spectrometry (ICP-MS) with low instrument detection capabilities for trace metal analyses, large dilution factors during sample preparation and low trace metal concentrations in the wastewaters limited the number of quantifiable determinations and likely influenced analytical accuracy. In contrast, all the labs measuring Ra in the wastewaters were able to report detectable concentrations using a variety of methods including gamma spectroscopy and wet chemical approaches following Environmental Protection Agency (EPA) standard methods. However, the reported radium activities were often greater than ±30% different to the MPV possibly due to calibration inconsistencies among labs, radon leakage, or failing to correct for self-attenuation. Reported radium activities in solid materials had less variability (±20% from MPV) but accuracy could likely be improved by using certified radium standards and accounting for self-attenuation that results from matrix interferences or a density difference between the calibration standard and the unknown sample. This inter-laboratory comparison illustrates that numerous methods can be used to measure major cation, minor cation, and anion concentrations in O&G wastewaters with relatively high accuracy while trace metal(loid) and radioactivity analyses in liquids may often be over ±20% different from the MPV.

Elevated gold ellipse nanoantenna dimers as sensitive and tunable surface enhanced Raman spectroscopy substrates.

We demonstrate large area arrays of elevated gold ellipse dimers with precisely controlled gaps for use as sensitive and highly controllable surface enhanced Raman scattering (SERS) substrates. The enhanced Raman signal observed with SERS arises from both localized and long range plasmonic effects. By controlling the geometry of a SERS substrate, in this case the size and aspect ratio of individual ellipses, the plasmon resonance can be tuned in a broad wavelength range, providing a method for designing the response of SERS substrates at different excitation wavelengths. Plasmon effects exhibited by the elevated gold ellipse dimer substrates are also demonstrated and confirmed through finite difference time domain (FDTD) simulations. A plasmon resonance red shift with an increase of the ellipse aspect ratio is observed, allowing systematic control of the resulting SERS signal intensity. Optimized elevated ellipse dimer substrates with 10 ± 2 nm gaps exhibit uniform SERS enhancement factors on the order of 10(9) for adsorbed p-mercaptoaniline molecules.

Vascular phenotypes in primary non-small cell lung carcinomas and matched brain metastases.

BACKGROUND: Anti-angiogenic therapy with bevacizumab (an anti-vascular endothelial growth factor (VEGF) antibody) predominantly targets immature blood vessels. Bevacizumab has shown a survival benefit in non-small cell lung carcinoma (NSCLC) and has recently been demonstrated to be safe in patients with brain metastases. However, it is not known whether bevacizumab is effective against brain metastases or whether metastases are representative of their primary in terms of VEGF expression, hypoxia, proliferation and vascular phenotype. The aim of this study was to evaluate these factors in a series of matched primary NSCLCs and brain metastases. METHODS AND RESULTS: Immunohistochemistry showed strong correlation of carbonic anhydrase 9 expression (a marker of hypoxia) in primary and secondary cancers (P=0.0002). However, the proliferation index, VEGF expression, microvessel density and the proportion of mature vessels were discordant between primary and secondary cancers. The mean proportion of mature vessels was 63.2% higher in the brain metastases than the primary tumours (P=0.004). Moreover, the vascular pattern of the primary tumour was not representative of the metastasis. CONCLUSIONS: Brain metastases have a significantly higher proportion of mature vasculature, suggesting that they may be refractory to anti-VEGF therapy. These findings may have implications for clinical trials and biomarker studies evaluating anti-angiogenic agents in brain metastases.

Expression of delta-like ligand 4 (Dll4) and markers of hypoxia in colon cancer.

BACKGROUND: Delta-like ligand 4 (Dll4) is a Notch ligand that is upregulated by hypoxia and vascular endothelial growth factor-A (VEGF-A) and is reported to have a role in tumor angiogenesis. Evidence from xenograft studies suggests that inhibiting Dll4-Notch signalling may overcome resistance to anti-VEGF therapy. The aim of this study was to characterise the expression of Dll4 in colon cancer and to assess whether it is associated with markers of hypoxia and prognosis. METHOD: In all, 177 colon cancers were represented in tissue microarrays. Immunohistochemistry was performed using validated antibodies against Dll4, VEGF, hypoxia-inducible factor (HIF)-1alpha, HIF-2alpha, prolyl hydroxylase (PHD)1, PHD2, PHD3 and carbonic anhydrase 9 (CA9). RESULTS: The expression of Dll4 was observed preferentially in the endothelium of 71% (125 out of 175) of colon cancers, but not in the endothelium adjacent to normal mucosa (none out of 107, P<0.0001). The expression of VEGF was significantly associated with HIF-2alpha (P<0.0001) and Dll4 (P=0.010). Only HIF-2alpha had a significant multivariate prognostic effect (hazard ratio 1.61, 95% confidence interval 1.01-2.57). Delta-like ligand 4 was also expressed by neoplastic cells, particularly neoplastic goblet cells. CONCLUSION: Endothelial expression of Dll4 is not a prognostic factor, but is significantly associated with VEGF. Assessing endothelial Dll4 expression may be critical in predicting response to anti-VEGF therapies.

Achaete-scute like 2 (ascl2) is a target of Wnt signalling and is upregulated in intestinal neoplasia.

Achaete-scute like (ASCL)2 is a basic helix-loop-helix transcription factor essential for the maintenance of proliferating trophoblasts during placental development. Using oligonucleotide microarrays we identified ascl2 as a gene significantly upregulated in colorectal adenocarcinomas (n=36 cancers, n=16 normals; 15-fold, P<0.0001). This finding was confirmed by quantitative reverse transcriptase (RT)-PCR on large intestinal cancers (n=29 cancers, n=16 normals; 10-fold, P<0.0001). In situ hybridization for ascl2 demonstrated expression at the base of small and large intestinal crypts (n=304), but in no other normal tissues excepting placenta. By in situ hybridization, 52-71% of colorectal adenomas (n=187), 50-73% of large (n=327) and 33-64% of small intestinal adenocarcinomas (n=124) were positive for ascl2 expression. Upregulation of murine ascl2 was also observed using oligonucleotide microarrays, quantitative RT-PCR and in situ hybridization on apcmin/+ and apc1638N/+ smad4-/+ tumours. Tumour cell lines stably transfected with LEF1(DN) or APC2, or transiently transfected with short-interfering RNA (siRNA) against beta-catenin showed a significant downregulation of ascl2. Colocalization of ascl2 with nuclear beta-catenin was observed in 73 small intestinal adenocarcinomas (P=0.0008) and apcmin/+ tumours. Preliminary in vitro data suggest ascl2 may promote progression through the G2/M cell cycle checkpoint. In summary, ascl2 is a putative regulator of proliferation that is overexpressed in intestinal neoplasia.

Expression of vascular endothelial growth factor, hypoxia inducible factor 1alpha, and carbonic anhydrase IX in human tumours.

AIMS: To measure vascular endothelial growth factor (VEGF-A) mRNA in a large, diverse cohort of tumours and to investigate whether VEGF-A expression is associated with markers of hypoxia, including hypoxia inducible factor 1alpha (HIF-1alpha) and carbonic anhydrase IX (CA9). METHODS: The expression of VEGF-A and CA9 was assessed in 5067 fresh frozen human tissue samples and 238 cell lines by DNA microarray analysis. In addition, tissue microarrays were constructed from 388 malignancies to investigate the expression of VEGF-A and HIF-1alpha by in situ hybridisation and immunohistochemistry, respectively. RESULTS: VEGF-A was significantly upregulated in primary malignancies of the breast, cervix, colon and rectum, oesophagus, head and neck, kidney, ovary, skin, urinary system, and white blood cells by DNA microarray analysis. However, VEGF-A expression only correlated with CA9 expression in renal tissues. In the tissue microarrays, HIF-1alpha positive cores showed a significant increase in VEGF-A expression in lung, ovary, soft tissue, and thyroid malignancies. CONCLUSIONS: The expression of VEGF-A is upregulated in a large proportion of human malignancies, and may be associated with markers of hypoxia. VEGF-A expression can be induced in the absence of hypoxia and hypoxia does not always provoke VEGF-A upregulation in tumours.

Quantitative analysis of colorectal tissue microarrays by immunofluorescence and in situ hybridization.

The accuracy and reliability of in situ studies may be compromised by qualitative interpretations. Quantitation imposes a greater degree of objectivity, is more reproducible, and facilitates the clarity of definitions. The aim of this study was to validate the utility of laser imaging systems for the in situ quantitative analysis of gene expression in tissue microarrays. Immunofluorescence was employed to quantify the expression of the tumour suppressor p53, a marker of proliferation (Ki67), an endothelial cell marker (CD31), and the mismatch repair proteins human Mut L homologue 1 and human Mut S homologue 2 in an arrayed series of colorectal tissues (n = 110). Quantitative data on this panel of antigens were compared objectively with qualitative scoring of immunohistochemical chromogen deposition. In addition, the expression of vascular endothelial growth factor (VEGF)-A, placental growth factor, hepatocyte growth factor, and c-Met mRNA was quantified by phosphor image analysis of in situ hybridization reactions. The quantified data on p53, Ki67, and CD31 expression were significantly associated with the pathologist's score (p < or = 0.001). While hepatocyte growth factor and placental growth factor were not up-regulated, c-Met expression was increased up to 2.5-fold and the median VEGF-A expression was elevated 4-fold (p = 0.003) in this series of colorectal tumours. Laser imaging systems are therefore feasible for high-throughput, quantitative profiling of tissue microarrays.

Palliative care research: trading ethics for an evidence base.

Good medical practice requires evidence of effectiveness to address deficits in care, strive for further improvements, and justly apportion finite resources. Nevertheless, the potential of palliative care is still held back by a paucity of good evidence. These circumstances are largely attributable to perceived ethical challenges that allegedly distinguish dying patients as a special client class. In addition, practical limitations compromise the quality of evidence that can be obtained from empirical research on terminally ill subjects. This critique aims to appraise the need for focused research, in order to develop clinical and policy decisions that will guide health care professionals in their care of dying patients. Weighted against this need are tenets that value the practical and ethical challenges of palliative care research as unique and insurmountable. The review concludes that, provided investigators compassionately apply ethical principles to their work, there is no justification for not endeavouring to improve the quality of palliative care through research.

Methylation and colorectal cancer.

Statistics rate colorectal adenocarcinoma as the most common cause of cancer death on exclusion of smoking-related neoplasia. However, the reported accumulation of genetic lesions over the adenoma to adenocarcinoma sequence cannot wholly account for the neoplastic phenotype. Recently, heritable, epigenetic changes in DNA methylation, in association with a repressive chromatin structure, have been identified as critical determinants of tumour progression. Indeed, the transcriptional silencing of both established and novel tumour suppressor genes has been attributed to the aberrant cytosine methylation of promoter-region CpG islands. This review aims to set these epigenetic changes within the context of the colorectal adenoma to adenocarcinoma sequence. The role of cytosine methylation in physiological and pathological gene silencing is discussed and the events behind aberrant cytosine methylation in ageing and cancer are appraised. Emphasis is placed on the interrelationships between epigenetic and genetic lesions and the manner in which they cooperate to define a CpG island methylator phenotype at an early stage in tumourigenesis. Finally, the applications of epigenetics to molecular pathology and patient diagnosis and treatment are reviewed.