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  • Bio-degradation  (1)
  • Chemiluminescence  (1)
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  • 1
    ISSN: 1420-908X
    Keywords: Silica ; Lung ; Inflammation ; Dexamethasone ; Peroxynitrite ; Chemiluminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and laboratory animals. Currently, no effective treatment exists for workers who may have been exposed to the inhalation of silica. The objective of this study was to develop an animal model in which we could evaluate the effect that anti-inflammatory steroids have on the acute silica-induced pulmonary inflammatory response. Male Fischer 344 rats were pretreated with either dexamethasone (2 mg/kg) or saline vehicle (i.p.) on days 1, 3, and 5. On day 6, the animals from the two groups were then intratracheally instilled with either silica (20 mg/0.5 ml saline vehicle) or saline vehicle (0.5 ml). Twenty-four hours after the instillations in the non-steroid group, significant increases occurred in total protein, total number of cells, neutrophils, and lymphocytes recovered from the lungs of animals treated with silica compared to saline controls. Silica also caused dramatic increases in the luminol-dependent chemiluminescence (LDCL) of lung tissue and bronchoalveolar lavage (BAL) cells. The LDCL reaction was markedly decreased by either superoxide dismutase (SOD) orN-nitro-l-arginine methyl ester hydrochloride (l-NAME). SOD is involved in the enzymatic breakdown of superoxide anion, whilel-NAME, a nitric oxide (NO) synthase inhibitor, prevents the formation of NO. When the superoxide anion and NO react, they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent which may be involved in the silica-induced oxidant lung injury. When the animals were pretreated with the steroid dexamethasone, there was a complete protection against the biochemical, cellular, and chemiluminescent indices of damage caused by silica. The mechanism in which the steroid protects the lung from damage may be due to the ability of dexamethasone to block the induction of NO synthase. With further study in animals, the anti-inflammatory steroids may be useful in the treatment of silicainduced lung injury.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 124, (2019): 8439-8454, doi: 10.1029/2019JC015637.
    Description: An Iranian tanker with 136,000 tons of natural gas condensates collided with a freighter in the East China Sea in January 2018 and, after drifting ablaze for 8 days and over 200 km, capsized on the edge of the shelf near the Kuroshio Current. Different from the crude oil, the condensates consist of hydrocarbons that have relatively high solubility in seawater. We postulate that the leakage from the remaining condensate cargo at 110 m depth may result in a bottom layer of condensate‐enriched water in the vicinity of the resting tanker. A model is constructed in this study to simulate the dispersion of contaminated water through the processes of oceanic advection, diffusion, biodegradation, and volatilization. It is found that the scope and magnitude of the dispersion are most sensitive to the biodegradation. Even though the biodegradation time scale depends on several factors that are not well quantified in this region, using any value within the estimated range from a previous study results in significant contamination in the broad area. The dispersion is particularly effective in this incident because the tanker capsized near the Kuroshio Current—a fast‐moving western boundary current. The Kuroshio acts as a fast conduit to spread the contaminant to the east coast of Japan and the interior Pacific Ocean. In addition, we identify that the Tsushima Warm Current, a perennial flow into the Japan Sea, is the second major conduit for spreading the polluted water. This study indicates that dissolved hydrocarbons are the main environmental risk for maritime spills of natural gas condensates.
    Description: Chris Reddy at WHOI provided invaluable guidance at the beginning of this study. Jian Zhao at UMD participated in some early discussions and helped the model development. Lei Chen has been financially supported by China Scholarship Council to study at WHOI for 2 years as a WHOI guest student. Jiayan Yang's participation in this study has been supported by the Woods Hole Oceanographic Institution‐Ocean University of China (WHOI‐OUC) Collaborative Initiative and the W. Van Alan Clark Chair for Excellence in Oceanography from WHOI. This work is supported by National Natural Science Foundation of China major project (41490640, 41490643). The daily oceanic velocity field used in the model is Global Ocean Sea Physical Analysis and Forecasting Products distributed by CMEMS, which can be available online (http://marine.copernicus.eu/services‐portfolio/access‐to‐products/?option=com_csw&view=details&product_id=GLOBAL_ANALYSIS_FORECAST_PHY_001_024). The model output data are available freely from the database of ZENODO (https://zenodo.org/record/3405388#.XXk‐5yhKhPY).
    Description: 2020-05-11
    Keywords: Maritime spill ; Natural gas condensates ; Bio-degradation ; East China and Japan Seas ; Kuroshio Current ; Tsushima Warm Current
    Repository Name: Woods Hole Open Access Server
    Type: Article
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