213 research outputs found
Submesoscale hotspots of productivity and respiration : insights from high-resolution oxygen and fluorescence sections
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 130 (2017): 1-11, doi:10.1016/j.dsr.2017.10.005.Modeling studies have shown that mesoscale and submesoscale processes can
stimulate phytoplankton productivity and export production. Here, we present observations from
an undulating, towed Video Plankton Recorder (VPR-II) in the tropical Atlantic. The VPR-II
collected profiles of oxygen, fluorescence, temperature and salinity in the upper 140 m of the
water column at a spatial resolution of 1 m in the vertical and <2 km in the horizontal. The data
reveal remarkable "hotspots", i.e. locations 5 to 10 km wide which have elevated fluorescence
and decreased oxygen, both of which are likely the result of intense submesoscale upwelling.
Based on estimates of source water, estimated from identical temperature and salinity surfaces,
hotspots are more often areas of net respiration than areas of net production â although the
inferred changes in oxygen are subject to uncertainty in the determination of the source of the
upwelled waters since the true source water may not have been sampled. We discuss the spatial
distribution of these hotspots and present a conceptual model outlining their possible generation
and decline. Simultaneous measurements of O2/Ar in the mixed layer from a shipboard mass
spectrometer provide estimates of rates of surface net community production. We find that the
subsurface biological hotspots are often expressed as an increase in mixed layer rates of net
community production. Overall, the large number of these hotspots support the growing evidence
that submesoscale processes are important drivers in upper ocean biological production.Funding for this work came from the National Science
Foundation (R.H.R.S. and D.J.M) (OCE-0925284, OCE-1048897, and OCE- 1029676) and the
National Aeronautics and Space Administration (D.J.M.) (NNX08AL71G and NNX13AE47G)
Interobserver agreement for single operator choledochoscopy imaging: can we do better?
Background. The SpyGlass Direct Visualization System (Boston Scientific, Natick, MA) is routinely used during single operator choledochoscopy (SOC) to identify biliary lesions or strictures with a diagnostic accuracy up to 88%. The objective of this study was to determine the interobserver agreement (IOA) of modified scoring criteria for diagnosing biliary lesions/strictures. Methods. 27 SPY SOC video clips were reviewed and scored by 9 interventional endoscopists based on published criteria that included the presence and severity of surface structure, vasculature visualization, lesions, and findings. Results. Overall IOA was slight for all variables. The K statistics are as follows: surface (K = 0.12, SE = 0.02); vessels (K = 0.14, SE = 0.02); lesions (K = 0.11, SE = 0.02); findings (K = 0.08, SE = 0.03); and final diagnosis (K = 0.08, SE = 0.02). The IOA for findings and final diagnosis was also only slight. The final diagnosis was malignant (11), benign (11), and indeterminate (5). Conclusion. IOA using the modified criteria of SOC images was slight to almost poor. The average accuracy was less than 50%. These findings reaffirm that imaging criteria for benign and malignant biliary pathology need to be formally established and validated
Identification of bloodâprotein carriers of the CA 19â9 antigen and characterization of prevalence in pancreatic diseases
The current best serum marker for pancreatic cancer, CA 19â9, detects a carbohydrate antigen on multiple protein carriers. Better knowledge of the protein carriers of the CA 19â9 antigen in various disease states may lead to improved diagnostic tests. To identify proteins that carry the CA 19â9 antigen, we immunoprecipitated the CA 19â9 antigen from pooled sera and identified the associated proteins using MS. Among the highâconfidence identifications, we confirmed the presence of the CA 19â9 antigen on Apolipoprotein Bâ100 by antibody arrays and Western blot and on kininogen, ARVCF, and Apolipoprotein E by antibody arrays. We characterized the frequency and levels of the CA 19â9 antigen on the four proteins across various patient groups (pancreatic cancer, pancreatitis, and healthy controls) using antibody arrays. Nearly, 10â25% of the subjects showed elevations of the antigen on each protein, but the elevations were not associated with disease state or total CA 19â9 levels. These results contribute to our knowledge of the carrier proteins of an important functional glycan and the rate at which the glycan is displayed. This work also demonstrates a strategy for using the complementary methods of MS and antibody microarrays to identify protein carriers of glycans and assess the diagnostic value of measuring glycans on individual proteins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87153/1/pmic_201000827_sm_SupplInfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/87153/2/3665_ftp.pd
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Volumetric laser endomicroscopy and its application to Barrett's esophagus: results from a 1,000 patient registry.
Volumetric laser endomicroscopy (VLE) uses optical coherence tomography (OCT) for real-time, microscopic cross-sectional imaging. A US-based multi-center registry was constructed to prospectively collect data on patients undergoing upper endoscopy during which a VLE scan was performed. The objective of this registry was to determine usage patterns of VLE in clinical practice and to estimate quantitative and qualitative performance metrics as they are applied to Barrett's esophagus (BE) management. All procedures utilized the NvisionVLE Imaging System (NinePoint Medical, Bedford, MA) which was used by investigators to identify the tissue types present, along with focal areas of concern. Following the VLE procedure, investigators were asked to answer six key questions regarding how VLE impacted each case. Statistical analyses including neoplasia diagnostic yield improvement using VLE was performed. One thousand patients were enrolled across 18 US trial sites from August 2014 through April 2016. In patients with previously diagnosed or suspected BE (894/1000), investigators used VLE and identified areas of concern not seen on white light endoscopy (WLE) in 59% of the procedures. VLE imaging also guided tissue acquisition and treatment in 71% and 54% of procedures, respectively. VLE as an adjunct modality improved the neoplasia diagnostic yield by 55% beyond the standard of care practice. In patients with no prior history of therapy, and without visual findings from other technologies, VLE-guided tissue acquisition increased neoplasia detection over random biopsies by 700%. Registry investigators reported that VLE improved the BE management process when used as an adjunct tissue acquisition and treatment guidance tool. The ability of VLE to image large segments of the esophagus with microscopic cross-sectional detail may provide additional benefits including higher yield biopsies and more efficient tissue acquisition. Clinicaltrials.gov NCT02215291
Barrett's esophagus: endoscopic treatments I
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87170/1/j.1749-6632.2011.06049.x.pd
Smart Atlas for Supporting the Interpretation of probe-based Confocal Laser Endomicroscopy (pCLE) of Gastric Lesions: First Classification Results of a Computer-Aided Diagnosis Software based on Image Recognition
International audiencepCLE enables microscopic imaging of gastrointestinal mucosal lesions, in vivo and in real time, during an endoscopy procedure. Recent studies have demonstrated that pCLE enables accurate diagnosis of superfcial gastric neoplasia. In parallel, a computer-aided diagnosis software called Smart Atlas has been developed to assist endoscopists with the interpretation of pCLE sequences. This study aims at evaluating the performance of this software for the classifcation of gastric lesions into four pathological classes: healthy stomach, gastric intestinal metaplasia (GIM), dysplasia, and cancer
Global prospective case series of ERCPs using a single-use duodenoscope
Background The first commercialized single-use duodenoscope was cleared by the US Food and Drug Administration in December 2019. Data regarding endoscopic retrograde cholangiopancreatography (ERCP) using a single-use duodenoscope are needed on a broader range of cases conducted by endoscopists with varying levels of experience in a wide range of geographic areas. Methods 61 endoscopists at 22 academic centers in 11 countries performed ERCP procedures in adult patients aged ? 18. Outcomes included ERCP completion for the intended indication, rate of crossover to a reusable endoscope, device performance ratings, and serious adverse events (SAEs). Results Among 551 patients, 236 (42.8 %) were aged >65, 281 (51.0 %) were men, and 256 (46.5 %) had their procedure as an inpatient. ERCPs included 196 (35.6 %) with American Society for Gastrointestinal Endoscopy complexity of grades 3 4. A total of 529 ERCPs (96.0 %) were completed: 503 (91.3 %) using only the single-use duodenoscope, and 26 (4.7 %) with crossover to a reusable endoscope. There were 22 ERCPs (4.0 %) that were not completed, of which 11 (2.0 %) included a crossover and 11 (2.0 %) were aborted cases (no crossover). Median ERCP completion time was 24.0 minutes. Median overall satisfaction with the single-use duodenoscope was 8.0 (scale of 1 to 10 [best]). SAEs were reported in 43 patients (7.8 %), including 17 (3.1 %) who developed post-ERCP pancreatitis. Conclusions In academic medical centers over a wide geographic distribution, endoscopists with varying levels of experience using the first marketed single-use duodenoscope had good ERCP procedural success and reported high performance ratings for this device.</p
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Light scattering spectroscopy identifies the malignant potential of pancreatic cysts during endoscopy
Pancreatic cancers are usually detected at an advanced stage and have poor prognosis. About one fifth of these arise from pancreatic cystic lesions. Yet not all lesions are precancerous, and imaging tools lack adequate accuracy for distinguishing precancerous from benign cysts. Therefore, decisions on surgical resection usually rely on endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Unfortunately, cyst fluid often contains few cells, and fluid chemical analysis lacks accuracy, resulting in dire consequences, including unnecessary pancreatic surgery for benign cysts and the development of cancer. Here, we report an optical spectroscopic technique, based on a spatial gating fibre-optic probe, that predicts the malignant potential of pancreatic cystic lesions during routine diagnostic EUS-FNA procedures. In a double-blind prospective study in 25 patients, with 14 cysts measured in vivo and 13 postoperatively, the technique achieved an overall accuracy of 95%, with a 95%confidence interval of 78â99%, in cysts with definitive diagnosis
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