789 research outputs found

    Local anesthetic resistance in a pregnant patient with lumbosacral plexopathy

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    BACKGROUND: We report a case of a patient with apparent resistance to local anesthetics. While similar cases of failure of regional anesthetics are often attributed to technical failure, the overall clinical presentation and history of this patient suggests a true resistance to local anesthetics. CASE PRESENTATION: This patient presented for elective cesarean section and the decision for regional anesthesia was made. While attempting to place an epidural, the patient failed to achieve adequate skin analgesia despite multiple attempts at local infiltration. When a spinal was ultimately placed, sensory or motor blockade was not obtained despite no evidence of technical problems with technique. Further questioning revealed multiple prior episodes of local anesthetic failure in this patient. CONCLUSIONS: While the failure rate of spinal anesthesia has been shown range from 4–13% and is often attributed to technical failure, elements of this particular case suggest a true resistance to local anesthetics

    The Future of Toxicity Testing for Environmental Contaminants

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    Research needs for the risk assessment of health and environmental effects of endocrine disruptors: A report of the US EPA-sponsored workshop

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    The hypothesis has been put forward that humans and wildlife species have suffered adverse health effects after exposure to endocrine-disrupting chemicals. Reported adverse effects include declines in populations, increases in cancers, and reduced reproductive function. The U.S. Environmental Protection Agency sponsored a workshop in April 1995 to bring together interested parties in an effort to identify research gaps related to this hypothesis and to establish priorities for future research activities. Approximately 90 invited participants were organized into work groups developed around the principal reported health effects-carcinogenesis, reproductive toxicity, neurotoxicity, and immunotoxicity--as well as along the risk assessment paradigm--hazard identification, dose-response assessment, exposure assessment, and risk characterization. Attention focused on both ecological and human health effects. In general, the group felt that the hypothesis warranted a concerted research effort to evaluate its validity and that research should focus primarily on effects on development of reproductive capability, on improved exposure assessment, and on the effects of mixtures. This report summarizes the discussions of the work groups and details the recommendations for additional research

    Profiling Chemicals Based on Chronic Toxicity Results from the U.S. EPA ToxRef Database

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    Attribute filters allow enhancement and extraction of features without distorting their borders, and never introduce new image features. These are highly desirable properties in biomedical imaging, where accurate shape analysis is paramount. However, setting the attribute-threshold parameters has to date only been done manually. This paper explores simple, fast and automated methods of computing attribute threshold parameters based on image segmentation, thresholding and data clustering techniques. Though several techniques perform well on blood-vessel filtering, the choice of technique appears to depend on the imaging mode.

    A cell‐free testing platform to screen chemicals of potential neurotoxic concern across twenty vertebrate species

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    There is global demand for new in vitro testing tools for ecological risk assessment. The objective of the present study was to apply a set of cell‐free neurochemical assays to screen many chemicals across many species in a relatively high‐throughput manner. The platform assessed 7 receptors and enzymes that mediate neurotransmission of γ‐aminobutyric acid, dopamine, glutamate, and acetylcholine. Each assay was optimized to work across 20 vertebrate species (5 fish, 5 birds, 7 mammalian wildlife, 3 biomedical species including humans). We tested the screening assay platform against 80 chemicals (23 pharmaceuticals and personal care products, 20 metal[loid]s, 22 polycyclic aromatic hydrocarbons and halogenated organic compounds, 15 pesticides). In total, 10 800 species–chemical–assay combinations were tested, and significant differences were found in 4041 cases. All 7 assays were significantly affected by at least one chemical in each species tested. Among the 80 chemicals tested, nearly all resulted in a significant impact on at least one species and one assay. The 5 most active chemicals were prochloraz, HgCl2, Sn, benzo[a]pyrene, and vinclozolin. Clustering analyses revealed groupings according to chemicals, species, and chemical–assay combinations. The results show that cell‐free assays can screen a large number of samples in a short period of time in a cost‐effective manner in a range of animals not easily studied using traditional approaches. Strengths and limitations of this approach are discussed, as well as next steps. Environ Toxicol Chem 2017;36:3081–3090. © 2017 SETACPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139122/1/etc3880.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139122/2/etc3880_am.pd
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