RESUMEN

Automated liquid handling (ALH) platforms are increasingly implemented in clinical laboratories to improve analytical reproducibility and replace manual handling during sample analysis. In clinical toxicology laboratories, ALH platforms are primarily utilized to perform sample preparation and extraction prior to subsequent analysis by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). When performing analysis with complex human biological matrices, verifying the performance characteristics of ALH platforms is required to ensure the assays' accuracy and reproducibility. Here, we evaluated and compared the analytical performances of Perkin Elmer JANUS® and Tecan Fluent® ALH systems in parallel, based on their performance in two toxicology assays designed to identify and quantify various opiates, semisynthetic opiates, and their metabolites. The comparability of the instrument platforms was evaluated by comparing assay analytical measuring range, total analytical imprecisions, and patient samples measurement when the ALH platforms are incorporated as part of the clinical assay's workflow. We have shown that both ALH platforms meet quality and performance criteria suitable for clinical toxicology assays. Nevertheless, the two platforms exhibit biases when measuring unknown patient samples. Such variations in their analytical performances may cause discrepancies when comparing results obtained from two different ALH platforms. In conclusion, it is important to consider how variations in ALH platform performances can affect patient results interpretation when implementing them in clinical laboratories.

Asunto(s)

Preparaciones Farmacéuticas/orina , Urinálisis/instrumentación , Cromatografía Liquida , Humanos , Espectrometría de Masas en Tándem , Pruebas de Toxicidad/instrumentación , Pruebas de Toxicidad/métodos , Urinálisis/métodos

RESUMEN

Southern New England salt marsh vegetation and habitats are changing rapidly in response to sea-level rise. At the same time, fiddler crab (Uca spp.) distributions have expanded and purple marsh crab (Sesarma reticulatum) grazing on creekbank vegetation has increased. Sea-level rise and reduced predation pressure drive these changing crab populations but most studies focus on one species; there is a need for community-level assessments of impacts from multiple crab species. There is also a need to identify additional factors that can affect crab populations. We sampled crabs and environmental parameters in four Rhode Island salt marshes in 2014 and compiled existing data to quantify trends in crab abundance and multiple factors that potentially affect crabs. Crab communities were dominated by fiddler and green crabs (Carcinus maenas); S. reticulatum was much less abundant. Burrow sizes suggest that Uca is responsible for most burrows. On the marsh platform, burrows and Carcinus abundance were negatively correlated with elevation, soil moisture, and soil percent organic matter and positively correlated with soil bulk density. Uca abundance was negatively correlated with Spartina patens cover and height and positively correlated with Spartina alterniflora cover and soil shear strength. Creekbank burrow density increased dramatically between 1998 and 2016. During the same time, fishing effort and the abundance of birds that prey on crabs decreased, and water levels increased. Unlike in other southern New England marshes where recreational overfishing is hypothesized to drive increasing marsh crab abundance, we propose that changes in crab abundance were likely unrelated to recreational finfish over-harvest; instead, they better track sea-level rise and changing abundances of alternate predators, such as birds. We predict that marsh crab abundance will continue to expand with ongoing sea-level rise, at least until inundation thresholds for crab survival are exceeded.

RESUMEN

This study evaluated the relative importance of the N arragansett Bay estuary (RI and MA, USA), and associated tidal rivers and coastal lagoons, as nurseries for juvenile winter flounder, Pseudopleuronectes americanus, and summer flounder, Paralichthys dentatus. Winter flounder (WF) and summer flounder (SF) abundance and growth were measured from May to October (2009-2013) and served as indicators for the use and quality of shallow-water habitats (water depth < 1.5-3.0 m). These bioindicators were then analyzed with respect to physiochemical conditions to determine the mechanisms underlying intra-specific habitat selection. WF and SF abundances were greatest in late May and June (maximum monthly mean = 4.9 and 0.55 flounder/m2 for WF and SF, respectively), and were significantly higher in the tidal rivers relative to the bay and lagoons. Habitat-related patterns in WF and SF abundance were primarily governed by their preferences for oligohaline (0.1-5 ppt) and mesohaline (6-18 ppt) waters, but also their respective avoidance of hypoxic conditions (< 4 mg DO/L) and warm water temperatures (> 25 °C). Flounder habitat usage was also positively related to sediment organic content, which may be due to these substrates having sufficiently high prey densities. WF growth rates (mean = 0.25 ± 0.14 mm/d) were negatively correlated with the abundance of conspecifics, whereas SF growth (mean = 1.39 ± 0.46 mm/d) was positively related to temperature and salinity. Also, contrary to expectations, flounder occupied habitats that offered no ostensible advantage in intra-specific growth rates. WF and SF exposed to low salinities in certain rivers likely experienced increased osmoregulatory costs, thereby reducing energy for somatic growth. Low-salinity habitats, however, may benefit flounder by providing refugia from predation or reduced competition with other estuarine fishes and macro-invertebrates. Examining WF and SF abundance and growth across each species' broader geographic distribution revealed that southern New England habitats may constitute functionally significant nurseries. These results also indicated that juvenile SF have a geographic range extending further north than previously recognized.