Concentrations of hydrophobic chemicals in mussels and semipermeable membrane devices (SPMDs) from nine studies published over the past decade, amended with new data obtained in the Scheldt−North Sea ...area, were assessed to understand the similarities and differences between these sampling matrixes. A model was developed to describe the concentration ratios, using literature values of elimination rate constants and steady-state accumulation factors of both samplers as key parameters. The model could successfully describe the results of seven studies. Differences in concentration ratios among these studies were related to the variability of mussel bioaccumulation factors (BAFs) and water sampling rates of SPMDs. For two studies, the model could only describe the data by adopting unrealistically high water sampling rates, and for one study there were not enough data to test the model. We argue that SPMDs will generally yield more reliable estimates of exposure concentrations than mussels, because in situ BAF values are difficult to estimate, whereas the in situ exchange kinetics of SPMDs can be quantified by measuring the dissipation rates of performance reference compounds. The implications of the results for future and existing monitoring programs are discussed.
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IJS, KILJ, NUK, PNG, UL, UM
The Banc d'Arguin, a non-estuarine area of shallows and intertidal flats off the tropical Saharan coast of Mauritania, is characterised by extensive intertidal and subtidal seagrass beds. We examined ...the characteristics of intertidal seagrass (
Zostera noltii) meadows and bare areas in terms of the presence and abundance of molluscs (gastropods and bivalves). To explain observed differences between molluscan assemblages in seagrass and bare patches, some aspects of the feeding habitat (top-5 mm of the sediment) and of food (organic materials) of molluscs were examined. The novelty of this study is that phytopigments were measured and identified to assess source and level of decay (freshness) of organic material in the sediment and to study their importance as an explanatory variable for the distribution of molluscs. Over an area of 36 km
2 of intertidal flats, at 12 sites, paired comparisons were made between seagrass-covered and nearby bare patches. Within seagrass meadows, dry mass of living seagrass was large and amounted to 180
±10 g AFDM m
−
2
(range 75–240). Containing twice the amount of silt per unit dry sediment mass, seagrass sediments were muddier than bare areas; the relative amount of organic material was also larger. The total number of species of bivalves and gastropods amounted to 27, 14 of which were found only in seagrass areas, 4 only in bare and 9 in both types of habitat. Among the three numerically most abundant species, the bivalves
Anadara senilis,
Dosinia hepatica and
Loripes lacteus, the first was numerically most abundant in bare and the other two in seagrass-covered areas. Bare intertidal areas had greater mean total biomass of molluscs (80.5 g AFDM m
−
2
) than seagrass meadows (30.0 g AFDM m
−
2
). In both habitats, the bulk of the biomass was made up by
A. senilis. Excluding this species, bare mudflats contained on average only 3.1 g AFDM m
−
2
and seagrass meadows 6.9 g AFDM m
−
2
. As compared to previous surveys in 1980–1986, the biomass of
A. senilis had increased almost 10-fold and
D. hepatica, previously found in very small numbers, had become the most numerous species. However, the total biomass excluding that of
A. senilis was similar. Concentrations of phytopigments were similar to those observed at temperate mudflats, indicating that the Banc d'Arguin might not be as oligotrophic as previously thought. Per unit of dry sediment mass, smaller amounts of phytopigments were found in bare than in seagrass areas. Per unit of dry organic material, bare sediments contained most (fresh) phytopigments. This suggests that in seagrass-covered meadows the organic material is more degraded than in bare sediments. Overall, the composition of phytopigments, quite surprisingly, indicated a benthic-diatom-dominated trophic system. Multivariate statistics revealed that patterns of zoobenthic assemblages were correlated with patterns of a combination of four environmental parameters: grain size of the sediment, amount of fresh phytopigments and amounts of leaves and roots of seagrass.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Surveillance of pancreatic cysts focuses on the detection of (mostly morphologic) features warranting surgery. European guidelines consider elevated CA19.9 as a relative indication for surgery. We ...aimed to evaluate the role of CA19.9 monitoring for early detection and management in a cyst surveillance population.
The PACYFIC-registry is a prospective collaboration that investigates the yield of pancreatic cyst surveillance performed at the discretion of the treating physician. We included participants for whom at least one serum CA19.9 value was determined by a minimum follow-up of 12 months.
Of 1865 PACYFIC participants, 685 met the inclusion criteria for this study (mean age 67 years, SD 10; 61% female). During a median follow-up of 25 months (IQR 24, 1966 visits), 29 participants developed high-grade dysplasia (HGD) or pancreatic cancer. At baseline, CA19.9 ranged from 1 to 591 kU/L (median 10 kU/L IQR 14), and was elevated (≥37 kU/L) in 64 participants (9%). During 191 of 1966 visits (10%), an elevated CA19.9 was detected, and these visits more often led to an intensified follow-up (42%) than those without an elevated CA19.9 (27%; p < 0.001). An elevated CA19.9 was the sole reason for surgery in five participants with benign disease (10%). The baseline CA19.9 value was (as continuous or dichotomous variable at the 37 kU/L threshold) not independently associated with HGD or pancreatic cancer development, whilst a CA19.9 of ≥ 133 kU/L was (HR 3.8, 95% CI 1.1-13, p = 0.03).
In this pancreatic cyst surveillance cohort, CA19.9 monitoring caused substantial harm by shortening surveillance intervals (and performance of unnecessary surgery). The current CA19.9 cutoff was not predictive of HGD and pancreatic cancer, whereas a higher cutoff may decrease false-positive values. The role of CA19.9 monitoring should be critically appraised prior to implementation in surveillance programs and guidelines.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Acute exacerbations of chronic hepatitis B virus (HBV) infection occur after withdrawal of lamivudine therapy in approximately 16% of patients and are considered of little clinical significance. We ...observed “lamivudine withdrawal hepatitis” accompanied by jaundice and incipient liver failure, but also followed by complete recovery and viral clearance. To investigate the incidence, severity, timing, and virologic characteristics of “lamivudine withdrawal hepatitis” we monitored 41 patients for at least 6 months after discontinuation of nucleoside analogue therapy. The incidence of hepatitis flares was estimated to be 7 of 41 (17%); in 2 of 41 cases (5%), hepatitis flares were associated with jaundice and incipient liver failure. A noticeable feature of the “lamivudine withdrawal hepatitis” flares were the high HBV-DNA levels at the time of the alanine transaminase (ALT) peak. All were wild-type HBV, even the one that emerged from a lamivudine-resistant strain during therapy. To minimize the risk of liver failure and to enhance the elimination of HBV following flares, lamivudine therapy was reinstituted in an icteric patient. Clinical and biochemical remission ensued, followed by loss of HBV DNA and hepatitis B e antigen (HBeAg) seroconversion. Such a virologic response did not occur in 5 other patients with a nonicteric “lamivudine withdrawal hepatitis,” who were not retreated with lamivudine. Hepatitis after withdrawal of lamivudine resembles acute hepatitis B with a predominance of anicteric flares within a time frame of 6 months. Active management of hepatitis flares following withdrawal of nucleoside analogue therapy should be investigated further.
(Hepatology 2000;32:635-639.)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Background and study aims
In this study, we evaluated the performance of community hospitals involved in the Dutch quality in endosonography team regarding yield of endoscopic ultrasound ...(EUS)-guided tissue acquisition (TA) of solid pancreatic lesions using cumulative sum (CUSUM) learning curves. The aims were to assess trends in quality over time and explore potential benefits of CUSUM as a feedback-tool.
Patients and methods
All consecutive EUS-guided TA procedures for solid pancreatic lesions were registered in five community hospitals between 2015 and 2018. CUSUM learning curves were plotted for overall performance and for performance per center. The American Society of Gastrointestinal Endoscopy-defined key performance indicators, rate of adequate sample (RAS), and diagnostic yield of malignancy (DYM) were used for this purpose. Feedback regarding performance was provided on multiple occasions at regional interest group meetings during the study period.
Results
A total of 431 EUS-guided TA procedures in 403 patients were included in this study. The overall and per center CUSUM curves for RAS improved over time. CUSUM curves for DYM revealed gradual improvement, reaching the predefined performance target (70 %) overall, and in three of five contributing centers in 2018. Analysis of a sudden downslope development in the CUSUM curve of DYM in one center revealed temporary absence of a senior cytopathologist to have had a temporary negative impact on performance.
Conclusions
CUSUM-derived learning curves allow for assessment of best practices by comparison among peers in a multidisciplinary multicenter quality improvement initiative and proved to be a valuable and easy-to-interpret means to evaluate EUS performance over time.
Abstract
Background and study aims
Endoscopic ultrasound (EUS)-guided tissue acquisition (TA) is the method of choice for establishing a pathological diagnosis of solid pancreatic lesions. Data on ...quality and yield of EUS-guided TA performed in community hospitals are lacking. A study was performed to determine and improve the diagnostic yield of EUS-guided TA in a group of community hospitals.
Methods
Following analysis of the last 20 EUS-guided TA procedures of solid pancreatic lesions performed in each of four community hospitals, a collaborative EUS interest group was formed and a prospective registry was started. During meetings of the interest group, feedback on results per center were provided and strategies for improvement were discussed.
Results
In the BEFORE team formation cohort, 80 procedures were performed in 66 patients. In the AFTER team formation cohort, 133 procedures were performed in 125 patients. After team formation, the rate of adequate sample increased from 80 % (95 %CI 0.7 – 0.9) to 95 % (95 %CI 0.9 – 1.0) , diagnostic yield of malignancy improved from 28 % (95 %CI 0.2 – 0.4) to 64 % (95 % CI 0.6 – 0.7), and sensitivity of malignancy improved from 63 % (95 %CI 0.4 – 0.8) to 84 % (95 %CI 0.8 – 0.9). Multivariate regression analysis revealed team formation to be the only variable significantly associated with an increased rate of adequate sample.
Conclusions
Formation of a regional EUS interest group with regular feedback on results per center, and discussions on methods and techniques used, significantly improved the outcome of EUS-guided TA procedures in patients with solid pancreatic lesions in community hospitals.
Diverse species assemblages are often associated with a diversity of habitat structures. Sedimentary systems seem to be no exception, as within sedimentary systems benthic species diversity within a ...sample point appears to correlate with sediment grain size complexity. However, it remains to be shown whether total benthic species diversity relates to a system’s sediment heterogeneity across multiple systems. In the present paper we examined whether bivalve diversity is associated with: (1) sediment heterogeneity across systems and (2) sediment grain size complexity within systems, at 9 temperate and tropical tidal flat systems. Although bivalve life-history strategies, like post-settlement habitat selection, might suggest that sediment heterogeneity should be important for bivalve species, bivalve diversity and sediment heterogeneity were not associated across systems. Interestingly, the association between total benthic diversity and sediment heterogeneity was also not significant, suggesting that changing species composition across systems does not account for the lack of a correlation between bivalve diversity and sediment heterogeneity. Instead of habitat differentiation, bivalve diversity within a sample point was highest in ‘complex’ fine-grained sediments and bivalve distributions showed a large degree of distributional overlap in all systems. The results of this study at both smaller and larger spatial scales suggest that coexistence between bivalve species in diverse tidal flats is not associated with increased sediment heterogeneity.
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BFBNIB, NUK, PNG, UL, UM, UPUK
Abstract
Background and study aims
The traditional “smear technique” for processing and assessing endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is sensitive to artifacts. Processing ...and evaluation of specimens collected in a liquid medium, liquid-based cytology (LBC) may be a solution. We compared the diagnostic value of EUS-FNA smears to LBC in pancreatic solid lesions in the absence of rapid on-site evaluation (ROSE).
Patients and methods
Consecutive patients who required EUS-FNA of a solid pancreatic lesion were included in seven hospitals in the Netherlands and followed for at least 12 months. Specimens from the first pass were split into two smears and a vial for LBC (using ThinPrep and/or Cell block). Smear and LBC were compared in terms of diagnostic accuracy for malignancy, sample quality, and diagnostic agreement between three cytopathologists.
Results
Diagnostic accuracy for malignancy was higher for LBC (82 % (58/71)) than for smear (66 % (47/71),
P
= 0.04), but did not differ when smears were compared to ThinPrep (71 % (30/42),
P
= 0.56) or Cell block (62 % (39/63),
P
= 0.61) individually. Artifacts were less often present in ThinPrep (57 % (24/42),
P
= 0.02) or Cell block samples (40 % (25/63),
P
< 0.001) than smears (76 % (54/71)). Agreement on malignancy was equally good for smears and LBC (ĸ = 0.71 versus ĸ = 0.70,
P
= 0.98), but lower for ThinPrep (ĸ = 0.26,
P
= 0.01) than smears.
Conclusion
After a single pass, LBC provides higher diagnostic accuracy than the conventional smear technique for EUS-FNA of solid pancreatic lesions in the absence of ROSE. Therefore, LBC, may be an alternative to the conventional smear technique, especially in centers lacking ROSE.
The extensive intertidal flats along Eighty-mile Beach in North-western Australia appear to be monotonous and homogeneous and seem ideally suited to study tidal zonation in macrozoo-benthic ...communities and their possible correlates with characteristics of the sediment. In October 1999, we sampled benthic invertebrates and sediments at a total of 895 sampling stations distributed over six different locations, each location separated by 15 km of unsampled foreshore along Eighty-mile Beach. To test for the presence or absence of patterns of tidal zonation (distinct height-related zones of specific sediment grain sizes or zoobenthic taxonomic groups) or patchiness (distinct patches of specific sediment grain sizes or zoobenthic taxonomic groups not related to tidal height) each location was divided into three along-shore sections and each section (transect) was examined at two or three tidal heights. Zonation was observed for sediment grain sizes. Sediments were coarser at the highest intertidal level and finer towards the low water line. Benthic assemblages also differed among tidal heights, but in terms of species-composition the differences were not consistent among the locations. Each location supported a unique collection of benthic invertebrates. Therefore the hypothesis of the presence of distinct zones of specific species or zoobenthic taxonomic groups was rejected; the presence of benthic patches was confirmed. The distribution of sediments and the composition of benthic assemblages were surprisingly poorly correlated compared to those reported in 12 previous quantitative studies around the world. One possible explanation might be that super-cyclone Vance, which hit the study-area only six months before this study, contributed to this poor correlation. Alternatively, the poor correlation may indicate that biotic interactions are more important than the assumed abiotic structuring.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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