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排序方式: 共有185条查询结果,搜索用时 15 毫秒
81.
Markus Brinkmann Sebastian Hudjetz Catrina Cofalla Sebastian Roger Ulrike Kammann John P. Giesy Markus Hecker Steve Wiseman Xiaowei Zhang Jan Wölz Holger Schüttrumpf Henner Hollert 《Journal of Soils and Sediments》2010,10(7):1347-1361
Purpose
One of the central issues related to global changes in weather is the increasing occurrence of flood events that can result in the re-suspension of contaminated sediments in rivers. Here, we report on a proof-of-concept study combining hydraulic engineering and ecotoxicology in a new interdisciplinary approach to assess the toxicity of re-suspended polluted sediments after a simulated flood event.Materials and methods
Rainbow trout (Oncorhynchus mykiss) were exposed for 5 days under simulated flood conditions in an annular flume with artificial sediments that were spiked with a mixture of polycyclic aromatic hydrocarbons (PAH) at environmentally relevant concentrations. Specifically, the objective of this study was to bridge the gap between the physical re-suspension of pollutants and resulting toxicological impacts on aquatic organisms. A suite of different molecular, biochemical and histological markers was used to test the hypothesis that re-suspension of sediments can lead to re-mobilization of PAHs and subsequently to effects on aquatic organisms.Results and discussion
The micronucleus frequency was significantly 4.3-fold elevated after exposure. There was no significant indication of Aryl hydrocarbon receptor signaling (no EROD induction or increased CYP1A protein content, only slight induction of CYP1A gene expression). Biliary metabolite concentration was the most sensitive marker of PAH exposure. Results for other biomarkers (glutathione-S-transferase, catalase and lipid peroxidation) were inconclusive.Conclusions
In combination with chemical analyses of suspended matter, the presented approach will be used to improve understanding of the re-mobilization of pollutants from sediments in support of environmental risk assessment. 相似文献82.
PURPOSE: The purpose of this study was to determine if intravenous hypertonic hydroxyethyl starch (7.5%/6%) (HES) could decrease the intraocular pressure (IOP) in healthy normotensive dogs, and compare its effect with that of mannitol (20%) (experimental study). In addition, the potential IOP-lowering effect of hypertonic HES was evaluated in six dogs with primary glaucoma (clinical study). MATERIAL AND METHODS: Experimental study: eight male ophthalmoscopically and clinically healthy Beagles were included in this study. The IOP of each dog was measured by applanation tonometry in both eyes to obtain control values at 10:00, 10:15, 10:30, 10:45, 11:00 a.m., and then every hour until 6:00 p.m. prior to the first treatment (control period). Each dog received, with at least 2-week intervals and in a random order, an intravenous (IV) infusion of 4 mL/kg hypertonic HES (1.2 g/kg NaCl; 0.96 g/kg HES) and 4 mL/kg mannitol 20% (1 g/kg) over a period of 15 min starting at 10:00 a.m. IOP was measured oculus uterque (OU) at the same time intervals as in the control study. The differences in IOP between the treatment groups and the baseline IOP (before the start of infusion), between oculus sinister (OS) and oculus dexter (OD) and between the same time points of all groups were determined with a Student's t-test for paired samples (P = 0.05). Clinical study: six dogs with primary glaucoma (representing seven eyes) received an IV infusion of 4 mL/kg hypertonic HES over a period of 15 min. IOP was measured before and 15 and 30 min after starting the infusion. RESULTS: Experimental study: no significant difference between IOP of both eyes was found. A significant decrease in IOP from baseline value was recorded at 15, 30, 45, and 60 min after the start of mannitol infusion (mean amplitude in IOP decrease 3.21 mmHg; P < 0.05) and at 15 and 30 min in dogs treated with HES (mean amplitude in IOP decrease 2.43 mmHg; P < 0.05). At 120 and 180 min there was a significantly higher IOP (P < 0.05) in HES treatment group compared to the values of the control group. Clinical study: in 5/7 eyes diagnosed with primary glaucoma a maximum decrease in IOP of an average of 24% from the baseline value (IOP before start of the infusion) was observed (range of decrease 2-21 mmHg). In three of these five cases the maximum decrease was reached at 15 min and in two cases at 30 min. In one case an increase in IOP of 35% (+ 18 mmHg) was seen after 15 min and 26% (+ 13 mmHg) after 30 min. Case 4 showed an increase in IOP of 5% (+ 3 mmHg) after 15 min and a decrease of 6% (- 4 mmHg) after 30 min. CONCLUSIONS: Intravenous hypertonic HES is comparable to intravenous mannitol 20% in lowering the intraocular pressure in healthy normotensive dogs. But this effect lasted half an hour longer after mannitol. In 6/7 eyes with primary glaucoma, hypertonic HES decreased IOP. 相似文献
83.
A set of 75 recombinant inbred lines (RILs) of the ITMI mapping population was grown under field conditions in Gatersleben. The lines were evaluated for the domestication traits pre-harvest sprouting and dormancy (germinability). Main QTLs could be localized for pre-harvest sprouting on chromosome 4AL and dormancy on chromosome 3AL. In addition, 85 Triticum aestivum cv. “Chinese Spring”-Aegilops tauschii introgression lines grown under greenhouse conditions were researched. No QTL could be found for pre-harvest sprouting but a major QTL could be detected for dormancy on chromosome 6DL. 相似文献
84.
Formation and classification of humus-rich marshland soils of the Weser marshland, Germany The formation and classification of marshland soils are still controversial. To improve the knowledge on the formation of humus-rich marshland soils 11 soil profiles have been investigated. The soils mostly showed Phragmitis in the subsoil. The Gr-horizons began at low depths (40–60 cm). The clay content was often about 60% and the Corg content up to 480 g kg?1. The amount of total sulfur was up to 29.6 g kg?1, that of exchangeable sulfate up to 4608 mg kg?1 and that of sulfate in the saturation extract 51.2 mg l?1. With pH (H2O) values between 2.0 and 7.4, Carbonate/S ratios < 3 and total sulfur contents > 7.5 g kg?1 some soils showed “Actual Acid Sulfate Soil” (AASS) properties. The pH(per) values varied between 2.4 and 7.1, thus some profiles showed “Potential Acid Sulfate Soils” (PASS) properties. Brakish as well as marine environments with an intensive sulfur dynamics and carbonate leaching are likely within the geogenetic phase of soil development. Via the control of the water regime the pedogenetic phase is mainly of anthropogenic influence. We propose to classify humus-rich marshland soils into “Organomarsch” and “Thiomarsch” on the soil type level of the German systematics. 相似文献
85.
Harvey RJ Depner UB Wässle H Ahmadi S Heindl C Reinold H Smart TG Harvey K Schütz B Abo-Salem OM Zimmer A Poisbeau P Welzl H Wolfer DP Betz H Zeilhofer HU Müller U 《Science (New York, N.Y.)》2004,304(5672):884-887
Prostaglandin E2 (PGE2) is a crucial mediator of inflammatory pain sensitization. Here, we demonstrate that inhibition of a specific glycine receptor subtype (GlyR alpha3) by PGE2-induced receptor phosphorylation underlies central inflammatory pain sensitization. We show that GlyR alpha3 is distinctly expressed in superficial layers of the spinal cord dorsal horn. Mice deficient in GlyR alpha3 not only lack the inhibition of glycinergic neurotransmission by PGE2 seen in wild-type mice but also show a reduction in pain sensitization induced by spinal PGE2 injection or peripheral inflammation. Thus, GlyR alpha3 may provide a previously unrecognized molecular target in pain therapy. 相似文献
86.
Altay UM Skerritt GC Hilbe M Ehrensperger F Steffen F 《Journal of the American Animal Hospital Association》2011,47(2):89-97
Sixteen cats with cerebrovascular disease confirmed via histology to be of nontraumatic and nonneoplastic origins are described. In addition, the anatomy of the arterial supply of the cat's brain is reviewed. It is suggested that this unique arterial design may influence the incidence of cerebrovascular accidents in this species. Of the 16 cats reviewed, seven cats had ischemic infarctions, five had hemorrhagic infarctions, and four were diagnosed with intracranial hemorrhage. The median age was 8 yr and 9.5 yr in cats with infarctions and intracranial hemorrhages, respectively. Clinical signs were severe, acute, consistent with the localization of the cerebrovascular lesion, and influenced by underlying pathology. Four cats with infarction showed lateralized neurologic signs. Four cats with infarctions were diagnosed with pulmonary disease antemortem and three cats had hyperthyroidism. Cerebrospinal fluid analysis and computed tomography scans were available in two cats. None of the infarctions were grossly visible. All cats with hemorrhagic infarcts had severe liver pathology and nephritis was identified in four cats. Hypoxia was a feature in four cats and one cat suffered cardiac failure. In conclusion, the clinical picture is influenced by the type of cerebrovascular disease, the localization of the intracranial lesions, and any underlying pathology. 相似文献
87.
88.
Nuclear export of microRNA precursors 总被引:2,自引:0,他引:2
89.
Munderloh UG Lynch MJ Herron MJ Palmer AT Kurtti TJ Nelson RD Goodman JL 《Veterinary microbiology》2004,101(1):53-64
Anaplasma marginale and A. phagocytophilum are obligate intracellular, tick-borne pathogens that target erythrocytes and neutrophil granulocytes, respectively. Because ticks do not directly tap blood vessels, an intermediate tissue may mediate infection of blood cells. We considered that vascular endothelium interacts with circulating blood cells in vivo, and could be involved in pathogenesis and dissemination of the organisms. We used light and electron microscopy and immune labeling to show that A. phagocytophilum invaded rhesus (RF/6A), human (HMEC-1, MVEC), as well as bovine (BCE C/D-1b) endothelial cell lines, whereas A. marginale infected rhesus and bovine endothelial cells. A. marginale formed large intracellular inclusions that appeared smooth and solid at first, and subsequently coalesced into discrete granules. A. phagocytophilum formed numerous smaller inclusions in each cell. Within 1-3 weeks, the monolayers were destroyed, and lysed cultures were diluted onto fresh monolayers. Electron microscopy demonstrated uneven distribution of A. marginale inside large inclusions, with reticulated forms grouped more tightly than denser cells, whereas in A. phagocytophilum individual organisms appeared more evenly spaced. Specific polyclonal and monoclonal antibodies both labeled A. marginale and A. phagocytophilum in endothelial cells, and oligonucleotide primers complimentary to either A. marginale or A. phagocytophilum amplified their expected target from these cultures. In conclusion, we demonstrate that relevant microvascular endothelium is susceptible to anaplasmas in vitro and may present a link that could explain development of the immune response and persistent infection. 相似文献
90.
Jürgen Augustin Wolfgang Merbach Rainer Remus Ulrike Münchmeyer 《Archives of Agronomy and Soil Science》2013,59(4):287-305
Bis in jüngste Zeit war unklar, ob den in der Rhizosphäre, der Grenzschicht zwischen dem pflanzlichen Wurzelsystem und dem Boden, ablaufenden Vorgängen tatsächlich Relevanz für die C/N‐Umsetzungsprozesse auf ökosystemarer Ebene zukommt. Zielstellung eigener Arbeiten war es daher, auf der Grundlage von Tracern (14C, 15N) und immunologischen Techniken (DAS‐ELISA) Verfahren zur entwickeln und zu testen, die zur Klärung dieser Fragestellung beitragen. Wie l4C‐Impulsmarkierungsexperimente ergaben, werden bereits im Verlauf der Ontogenese beträchtliche Mengen des neu assimilierten Kohlenstoffs in die organische Bodensubstanz eingebaut (bei Sommerweizen zwischen 51 und 410% und bei Schilf 21% des Wurzel‐C). Mit Hilfe von DAS‐ELISA ausgeführte Studien ließen einen sehr differenzierten Einfluß von Getreidearten und ‐Sorten auf die Besiedlung der Rhizosphäre mit dem phytoeffektiven Bakterienstamm Pantoea agglomérons D5/23 erkennen. In überstautem Niedermoortorf bewirkte die Anwesenheit von Sumpfpflanzen (Schilf, Rohrglanzgras) eine beschleunigte Umsetzung von 15N‐markiertem Nitrat zu den gasförmigen Denitrifikationsprodukten N2O und N2. 相似文献