			Home About us Contact

Site-specific Analysis (site-specific + analysis)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Trends in water quality and discharge confound long-term warming effects on river macroinvertebrates

FRESHWATER BIOLOGY, Issue 2 2009
ISABELLE DURANCE
Summary 1.,Climate-change effects on rivers and streams might interact with other pressures, such as pollution, but long-term investigations are scarce. We assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989,2007). 2.,Long-term records, coupled with estimates from inter-site calibrations of 3,4 years, showed that mean stream temperatures in the study area had increased by 2.1,2.9 °C in winter and 1.1,1.5 °C in summer over the 26 year period from 1980 to 2006, with trends in winter strongest. 3.,While invertebrate assemblages in surface-fed streams were constant, those in chalk-streams changed significantly during 1989,2007. Invertebrate trends correlated significantly with temperature, but effects were spurious because (i) assemblages gained taxa typical of faster flow or well-oxygenated conditions, contrary to expectations from warming; (ii) more invertebrate families increased in abundance than declined and (iii) concomitant changes in water quality (e.g. declining orthophosphate, ammonia and biochemical oxygen demand), or at some sites changes in discharge, explained more variation in invertebrate abundance and composition than did temperature. 4.,These patterns were reconfirmed in both group- and site-specific analyses. 5.,We conclude that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality. This implies that positive management can minimize some climate-change impacts on stream ecosystems. Chalk-stream invertebrates are sensitive, nevertheless, to variations in discharge, and detectable changes could occur if climate change alters flow pattern. 6.,Because climatic trends now characterize many inter-annual time-series, we caution other investigators to examine whether putative effects on ecological systems are real or linked spuriously to other causes of change. [source]

Technical issues affecting the implementation of US Environmental Protection Agency's proposed fish tissue-based aquatic criterion for selenium,

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2007
A Dennis Lemly
Abstract The US Environmental Protection Agency is developing a national water quality criterion for selenium that is based on concentrations of the element in fish tissue. Although this approach offers advantages over the current water-based regulations, it also presents new challenges with respect to implementation. A comprehensive protocol that answers the "what, where, and when" is essential with the new tissue-based approach in order to ensure proper acquisition of data that apply to the criterion. Dischargers will need to understand selenium transport, cycling, and bioaccumulation in order to effectively monitor for the criterion and, if necessary, develop site-specific standards. This paper discusses 11 key issues that affect the implementation of a tissue-based criterion, ranging from the selection of fish species to the importance of hydrological units in the sampling design. It also outlines a strategy that incorporates both water column and tissue-based approaches. A national generic safety-net water criterion could be combined with a fish tissue,based criterion for site-specific implementation. For the majority of waters nationwide, National Pollution Discharge Elimination System permitting and other activities associated with the Clean Water Act could continue without the increased expense of sampling and interpreting biological materials. Dischargers would do biotic sampling intermittently (not a routine monitoring burden) on fish tissue relative to the fish tissue criterion. Only when the fish tissue criterion is exceeded would a full site-specific analysis including development of intermedia translation factors be necessary. [source]

Mass spectrometry for the study of protein glycation in disease

MASS SPECTROMETRY REVIEWS, Issue 5 2006
Toshimitsu Niwa
Abstract The structural elucidation of advanced glycation end-product (AGE)-modified proteins and quantitative analysis of free AGEs have been successfully performed, by use of mass spectrometry (MS) in plasma and tissues of patients with AGE-related diseases, such as diabetes mellitus, uremia, cataract, and liver cirrhosis. Matrix-assisted laser desorption/ionization (MALDI)-MS made it possible to directly analyze the AGE-modified proteins such as albumin and IgG. However, because the direct structural analysis of intact AGE-modified proteins is often not easy due to the formation of broad and poorly resolved peaks, peptide mapping after enzymatic hydrolysis was introduced into the analysis of AGE-modified proteins and the site-specific analysis of defined AGEs by MALDI-MS. Liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) has been employed not only for the structural elucidation of enzymatically hydrolyzed AGEs-modified peptides but also for simultaneous quantification of free AGEs in plasma and tissues of patients. Based on many studies that use MS for the analysis of AGEs, there is no doubt as to the important role of protein-linked AGEs in several diseases. © 2006 Wiley-Liss, Inc. [source]

Case report: de novo BRCA2 gene mutation in a 35-year-old woman with breast cancer

CLINICAL GENETICS, Issue 5 2009
M Marshall
In this report, we describe a patient with a de novo BRCA2 gene mutation (5301insA) who developed early onset breast cancer with no strong family history of the disease. Only three similar instances have been reported previously. Subsequent site-specific analysis in her parents showed that neither carried the mutation previously identified in their daughter. Various possible explanations for this finding were excluded. Paternity was confirmed using 13 highly polymorphic markers, thereby illustrating that the patient carried a de novo mutation in the BRCA2 gene. The 5301insA mutation has been well described and reported many times in the Breast Cancer Information Core online Breast Cancer Mutation database. This finding illustrates the importance of determining the incidence of de novo BRCA mutations and is of significant clinical value to breast cancer prevention and management. Our case report presents the fourth case in which a de novo germline mutation in a BRCA1/2 gene has been identified. [source]