Video-assisted thoracic surgery (VATS) as a safe alternative for the resection of pulmonary metastases: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>VATS has become a preferred method for benign surgical conditions, yet still remains controversial for malignancies. The purpose of this study was to review our results of pulmonary metastasectomies using both conventional open thoracotomy and VATS techniques.</p> <p>Methods</p> <p>This is a retrospective chart review of pulmonary metastasectomies performed from 1986 to 2006. The surgical approach used for the initial pulmonary metastasectomy was either open thoracotomy or VATS. Main outcomes were overall survival and recurrence free survival, evaluated using Kaplan Meier analysis. A non-inferiority margin was set at 0.2.</p> <p>Results</p> <p>A total of 280 surgical procedures were performed on 186 patients. From 171 eligible individuals, 135 patients were treated with thoracotomy (82 M, 53 F; median age 49 years), and 36 with VATS (18 M, 18 F; median age 58.5 years). Primary cancers were mainly: 81 sarcoma (47%), 26 colorectal adenocarcinoma (15%) and 22 renal cell carcinoma (13%). Median postoperative follow was 26.2 months. The conversion rate was 10.3% and there were no cases of pleural cavity seeding. The 5-year overall survival rates were 58.8% for thoracotomy and 69.6% for VATS, with median overall survival of 53.2 months and 30.1 months, respectively (p = 0.03). The estimated difference in 5-year overall survival was 10.8%. Second occurrences were noted in 59 thoracotomy and 10 VATS patients. The 5-year recurrence free survival rates were 51% in thoracotomy and 67% in VATS (p = 0.27), with median recurrence free survival of 24.8 months and 25.6 months, respectively.</p> <p>Conclusion</p> <p>In cases of pulmonary metastases, VATS is an acceptable alternative that is both safe and efficacious. Non-inferiority analysis of 5-year overall survival demonstrates that VATS is equivalent to thoracotomy. VATS patients also have a longer recurrence free survival. Based on our experience, it is permissible to use VATS resection in these circumstances: small tumor, fewer nodules, single lesion, age ≤ 53, unilateral, tumor size amenable to wedge resection, and non-recurrent disease.</p

Isotopic signals (18O, 2H, 3H) of six major rivers draining the pan-Arctic watershed

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 26 (2012): GB1027, doi:10.1029/2011GB004159.We present the results of a 4-year collaborative sampling effort that measured δ18O, δ2H values and 3H activities in the six largest Arctic rivers (the Ob, Yenisey, Lena, Kolyma, Yukon and Mackenzie). Using consistent sampling and data processing protocols, these isotopic measurements provide the best available δ2H and 3H estimates for freshwater fluxes from the pan-Arctic watershed to the Arctic Ocean and adjacent seas, which complements previous efforts with δ18O and other tracers. Flow-weighted annual δ2H values vary from −113.3‰ to −171.4‰ among rivers. Annual 3H fluxes vary from 0.68 g to 4.12 g among basins. The integration of conventional hydrological and landscape observations with stable water isotope signals, and estimation of areal yield of 3H provide useful insights for understanding water sources, mixing and evaporation losses in these river basins. For example, an inverse correlation between the slope of the δ18O-δ2H relation and wetland extent indicates that wetlands play comparatively important roles affecting evaporation losses in the Yukon and Mackenzie basins. Tritium areal yields (ranging from 0.760 to 1.695 10−6 g/km2 per year) are found to be positively correlated with permafrost coverage within the studied drainage basins. Isotope-discharge relationships demonstrate both linear and nonlinear response patterns, which highlights the complexity of hydrological processes in large Arctic river basins. These isotope observations and their relationship to discharge and landscape features indicate that basin-specific characteristics significantly influence hydrological processes in the pan-Arctic watershed.Funding for this research was provided by the U.S. National Science Foundation (OPP-0229302), the National Science and Engineering Research Council of Canada (Discovery grant to JJG and IRD fellowship to YY), the U.S. Geological Survey and the Water Resources Division in the Department of Indian Affairs and Northern Development, Canada.2012-09-2

Nitrogen dynamic in Eurasian coastal Arctic ecosystem: Insight from nitrogen isotope

Primary productivity is limited by the availability of nitrogen (N) in most of the coastal Arctic, as a large portion of N is released by the spring freshet and completely consumed during the following summer. Thus, understanding the fate of riverine nitrogen is critical to identify the link between dissolved nitrogen dynamic and coastal primary productivity to foresee upcoming changes in the Arctic seas, such as increase riverine discharge and permafrost thaw. Here, we provide a field-based study of nitrogen dynamic over the Laptev Sea shelf based on isotope geochemistry. We demonstrate that while most of the nitrate found under the surface fresh water layer is of remineralized origin, some of the nitrate originates from atmospheric input and was probably transported at depth by the mixing of brine-enriched denser water during sea-ice formation. Moreover, our results suggest that riverine dissolved organic nitrogen (DON) represents up to 6 times the total riverine release of nitrate and that about 62 to 76% of the DON is removed within the shelf waters. This is a crucial information regarding the near-future impact of climate change on primary productivity in the Eurasian coastal Arctic

High export of dissolved silica from the Greenland Ice Sheet

Silica is an essential element for marine life and plays a key role in the biogeochemistry of the ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported to coastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial areas such as the Greenland Ice Sheet is presently poorly quantified and not accounted for in global budgets. Here we present data from two fjord systems adjacent to the Greenland Ice Sheet which reveal a large export of dissolved silica by glacial meltwater relative to other macronutrients. Upscaled to the entire Greenland Ice Sheet, the export of dissolved silica equals 22 ± 10 Gmol Si yr−1. When the silicate-rich meltwater mixes with upwelled deep water, either inside or outside Greenland's fjords, primary production takes place at increased silicate to nitrate ratios. This likely stimulates the growth of diatoms relative to other phytoplankton groups

Video-assisted thoracic surgery (VATS) for resection of metastatic adenocarcinoma as an acceptable alternative

Adenocarcinomas commonly metastasize to the lungs and can be resected using open thoracotomy or video-assisted thoracic surgery (VATS). This study reviews metastatic resections in primary adenocarcinoma patients, using both thoracotomy and VATS. We aim to compare long-term prognoses to test the efficacy and viability of VATS. A retrospective review of primary adenocarcinoma patients who underwent resection of pulmonary metastases from 1990 to 2006 was carried out. Information was obtained by chart review. Endpoints analyzed were disease-free interval (DFI), survival time, and recurrence-free survival (RFS). In a total of 42 (16 male, 26 female; median age 58.5 years) primary adenocarcinoma patients, 21 patients underwent first pulmonary metastatic resection using VATS (7 male, 14 female; median age 57 years) and 21 using thoracotomy (9 male, 12 female; median age 59 years). Primary adenocarcinomas were mainly 27 colorectal (64%) and 11 breast (26%). Two VATS (10%) and three open patients (14%) had local recurrences of the original cancer. Median postoperative follow was 13.3 months [interquartile range (IQR) 4.5–32.8 months] for VATS and 36.9 months (IQR 19.3–48.6 months) after thoracotomy. Median DFI–1 was 22.3 months (IQR 13.5–40.6 months) for VATS patients and 35.6 months (IQR 26.7–61.3 months) for open patients. Second thoracic occurrences were noted in six VATS patients (median DFI–2 9.2 months), and in seven open patients (median DFI-2 21.5 months). Third thoracic occurrences were noted in one VATS patient (DFI-3 18.7 months) and in one thoracotomy patient (DFI-3 21.8 months). Odds ratio of recurrence showed 12.5% less chance of developing recurrence in VATS patients. Five-year RFS was 53% in VATS and 57% in thoracotomy patients. VATS has become a viable alternative to open thoracotomy for resection of pulmonary metastases. In cases of primary adenocarcinoma, VATS showed no increase in number of thoracic recurrences, and comparable RFS. Short-term follow-up is encouraging; long-term follow-up will be needed to confirm these results

The processing and impact of dissolved riverine nitrogen in the Arctic Ocean

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 35 (2012): 401-415, doi:10.1007/s12237-011-9417-3.Although the Arctic Ocean is the most riverine-influenced of all of the world’s oceans, the importance of terrigenous nutrients in this environment is poorly understood. This study couples estimates of circumpolar riverine nutrient fluxes from the PARTNERS (Pan-Arctic River Transport of Nutrients, Organic Matter, and Suspended Sediments) Project with a regionally configured version of the MIT general circulation model to develop estimates of the distribution and availability of dissolved riverine N in the Arctic Ocean, assess its importance for primary production, and compare these estimates to potential bacterial production fueled by riverine C. Because riverine dissolved organic nitrogen is remineralized slowly, riverine N is available for uptake well into the open ocean. Despite this, we estimate that even when recycling is considered, riverine N may support 0.5–1.5 Tmol C year−1 of primary production, a small proportion of total Arctic Ocean photosynthesis. Rapid uptake of dissolved inorganic nitrogen coupled with relatively high rates of dissolved organic nitrogen regeneration in N-limited nearshore regions, however, leads to potential localized rates of riverine-supported photosynthesis that represent a substantial proportion of nearshore production.Funding for this work was provided through NSFOPP- 0229302 and NSF-OPP-0732985.Support to SET was additionally provided by an NSERC Postdoctoral Fellowship

Dissolved iron in the Arctic shelf seas and surface waters of the Central Arctic Ocean: Impact of Arctic river water and ice-melt

Key Points - DFe in the Arctic shelves and surface is linked to freshwater and alkalinity - Fluvial input main contributor to high DFe, low alkalinity in Central Arctic - Remineralisation and biological depletion determine DFe in the Arctic Shelf Seas Abstract Concentrations of dissolved (10 nM) in the bottom waters of the Laptev Sea shelf may be attributed to either sediment resuspension, sinking of brine or regeneration of DFe in the lower layers. A significant correlation (R2 = 0.60) between salinity and DFe is observed. Using δ18O, salinity ,nutrients and total alkalinity data, the main source for the high (>2 nM) DFe concentrations in the Amundsen and Makarov Basins is identified as (Eurasian) river water, transported with the Transpolar Drift (TPD). On the North American side of the TPD, the DFe concentrations are low ( 4) above the shelf and low ( < 4) off the shelf)

The Brain Atlas Concordance Problem: Quantitative Comparison of Anatomical Parcellations

Many neuroscientific reports reference discrete macro-anatomical regions of the brain which were delineated according to a brain atlas or parcellation protocol. Currently, however, no widely accepted standards exist for partitioning the cortex and subcortical structures, or for assigning labels to the resulting regions, and many procedures are being actively used. Previous attempts to reconcile neuroanatomical nomenclatures have been largely qualitative, focusing on the development of thesauri or simple semantic mappings between terms. Here we take a fundamentally different approach, discounting the names of regions and instead comparing their definitions as spatial entities in an effort to provide more precise quantitative mappings between anatomical entities as defined by different atlases. We develop an analytical framework for studying this brain atlas concordance problem, and apply these methods in a comparison of eight diverse labeling methods used by the neuroimaging community. These analyses result in conditional probabilities that enable mapping between regions across atlases, which also form the input to graph-based methods for extracting higher-order relationships between sets of regions and to procedures for assessing the global similarity between different parcellations of the same brain. At a global scale, the overall results demonstrate a considerable lack of concordance between available parcellation schemes, falling within chance levels for some atlas pairs. At a finer level, this study reveals spatial relationships between sets of defined regions that are not obviously apparent; these are of high potential interest to researchers faced with the challenge of comparing results that were based on these different anatomical models, particularly when coordinate-based data are not available. The complexity of the spatial overlap patterns revealed points to problems for attempts to reconcile anatomical parcellations and nomenclatures using strictly qualitative and/or categorical methods. Detailed results from this study are made available via an interactive web site at http://obart.info