184 research outputs found

    Maximizing the general success of cecal intubation during propofol sedation in a multi-endoscopist academic centre

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    <p>Abstract</p> <p>Background</p> <p>Achieving the target of 95% colonoscopy completion rate at centres conducting colorectal screening programs is an important issue. Large centres and teaching hospitals employing endoscopists with different levels of training and expertise risk achieving worse results. Deep sedation with propofol in routine colonoscopy could maximize the results of cecal intubation.</p> <p>Methods</p> <p>The present study on the experience of a single centre focused on estimating the overall completion rate of colonoscopies performed under routine propofol sedation at a large teaching hospital with many operators involved, and on assessing the factors that influence the success rate of the procedure and how to improve this performance, analyzing the aspects relating to using of deep sedation. Twenty-one endoscopists, classified by their level of specialization in colonoscopic practice, performed 1381 colonoscopies under deep sedation. All actions needed for the anaesthesiologist to restore adequate oxygenation or hemodynamics, even for transient changes, were recorded.</p> <p>Results</p> <p>The "crude" overall completion rate was 93.3%. This finding shows that with routine deep sedation, the colonoscopy completion rate nears, but still does not reach, the target performance for colonoscopic screening programs, at centers where colonoscopists of difference experience are employed in such programs.</p> <p>Factors interfering with cecal intubation were: inadequate colon cleansing, endoscopists' expertise in colonoscopic practice, patients' body weight under 60 kg or age over 71 years, and the need for active intervention by the anaesthesiologist. The most favourable situation - a patient less than 71 years old with a body weight over 60 kg, an adequate bowel preparation, a "highly experienced specialist" performing the test, and no need for active anaesthesiological intervention during the procedure - coincided with a 98.8% probability of the colonoscopy being completed.</p> <p>Conclusions</p> <p>With routine deep sedation, the colonoscopy completion rate nears the target performance for colonoscopic screening programs, at centers where colonoscopists of difference experience are employed in such programs. Organizing the daily workload to prevent negative factors affecting the success rate from occurring in combination may enable up to 85% of incomplete procedures to be converted into successful colonoscopies.</p

    Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition

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    <p>Abstract</p> <p>Background</p> <p>The role of coastal nutrient sources in the persistence of <it>Karenia brevis </it>red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' <it>trans</it>-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of <it>K. brevis </it>is responsive to nitrogen and phosphorus and is informative of nutrient status.</p> <p>Results</p> <p>Microarray analysis of N-depleted <it>K. brevis </it>cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10<sup>-4</sup>. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes.</p> <p>Conclusions</p> <p>Microarray analysis provided transcriptomic evidence for N- but not P-limitation in <it>K. brevis</it>. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.</p

    Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary

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    Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L−1. Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality

    S-D logic-informed customer engagement: Integrative framework, revised fundamental propositions, and application to CRM

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