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  • 1
    Electronic Resource
    Electronic Resource
    Uptake of Nitrate by Mutants of Arabidopsis thaliana, Disturbed in Uptake or Reduction of Nitrate (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 43 (1978), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A study of nitrate and chlorate uptake by Arabidopsis thaliana was made with a wildtype and two mutant types, both mutants having been selected by resistance to high chlorate concentrations. All plants were grown on a nutrient solution with nitrate and/or ammonium as the nitrogen source. Uptake was determined from depletion in the ambient solution. Nitrate and chlorate were able to induce their own uptake mechanisms. Plants grown on ammonium nitrate showed a higher subsequent uptake rate of nitrate and chlorate than plants grown on ammonium alone.Mutant B25, which has no nitrate reductase activity, showed higher rates of nitrate and chlorate uptake than the wildtype, when both types were grown on ammonium nitrate. Therefore, the uptake of nitrate is not dependent on the presence of nitrate reductase. Nitrate has a stimulating effect on nitrate and chlorate uptake, whereas some product of nitrate and ammonium assimilation inhibits uptake of both ions by negative feedback. Mutant B 1, which was supposed to have a low chlorate uptake rate, also has disturbed uptake characteristics for nitrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1978.tb01592.x
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  • 2
    Electronic Resource
    Electronic Resource
    Chlorate Toxicity and Nitrate Reductase Activity in Tomato Plants (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 41 (1977), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Chlorate damage was studied in tomato plants (Lycopersicum esculentum cv. Moneymaker) that were supplied with a nitrogen-free nutrient solution or with a nutrient solution, containing either nitrate or ammonium as a nitrogen source. Damage was low in ammonium-fed plants and high in nitrate-fed plants and in nitrogen-less plants. Nitrate reductase activity could be detected in all treatments, although the activity was highest in the nitrate-fed plants.The hypothesis that chlorate can be used as a substrate by the enzyme nitrate reductase in higher plants, was studied and proved to be true for the tomato plants, as was found earlier for Escherichia and Chlorella. The affinity of the enzyme for chlorate was lower than for nitrate, the Km being 4 mM and 0.15 mM respectively. Induction of the enzyme by chlorate could not be detected. The enzyme activity was lowered in leaf discs after a 7 h treatment with chlorate and the inhibition was proportional to the chlorate concentration of the medium.The results were discussed in terms of competition between nitrate and chlorate at the uptake and the enzyme site and with regard to a possible influence of chlorate on synthesis and breakdown of the enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1977.tb01524.x
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of the air pollution component ammonium sulphate on the VAM infection rate of three heathland species (1992)
    Springer
    Plant and soil 144 (1992), S. 1-12 
    Details
    ISSN: 1573-5036
    Keywords: air pollution ; ammonium sulphate ; Antennaria dioica ; Arnica montana ; Glomus fasciculatum ; heathland vegetation ; Hieracium pilosella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three heathand species, Antennaria dioica, Arnica montana and Hieracium pilosella, were artificially rained with ammonium sulphate solutions at increasing concentrations in a greenhouse experiment. The same species were also artificially rained with increasing ammonium sulphate solutions under field conditions. Dry weights of the plants in the field experiments did not change with increasing ammonium sulphate applications. Nor did the dry weights of plants in the greenhouse experiments change with increasing ammonium sulphate concentrations, except for Arnica montana, which showed an increase in dry weight. VAM infection percentage of Antennaria dioica increased in both the greenhouse and the field experiment. The results of the field experiment show that VAM infection rates are reduced after two years of artificial rain in the plant species Arnica montana, which grows naturally under nutrient poor conditions and is presently declining in its natural habitat in the Netherlands. In the greenhouse experiment, VAM infection of Arnica montana did not change with increasing ammonium sulphate concentrations. VAM infection rates of Hieracium pilosella, which presently is not declining, did not change with increasing ammonium sulphate concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018839
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  • 4
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    Effect of the air pollution component ammonium sulphate on the VAM infection rate of three heathland species (1992)
    Springer
    Details
    Publication Date: 1992-07-01
    Print ISSN: 0032-079X
    Electronic ISSN: 1573-5036
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Springer
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  • 5
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    Inhibition of Pulmonary Coagulopathy by Nebulized Natural Anticoagulants during Streptococcus Pneumoniae Pneumonia in Rats (2008)
    American Society of Hematology
    Details
    Publication Date: 2008-11-16
    Description: RATIONALE: Alveolar fibrin deposition is intrinsic to pneumonia and acute lung injury. Activation of coagulation during pulmonary inflammation is primarily mediated by the tissue factor–factor VIIa pathway. Tissue factor levels in the lungs increase during pulmonary inflammation due to disruption of endothelial–epithelial barrier and expression of tissue factor on alveolar macrophages. Intravenous infusion of the natural anticoagulants activated protein C (APC) or antithrombin (AT) has been shown to have lung–protective effects in critically ill patients, but increases the risk of severe bleeding. Local administration may allow for higher treatment dosages and increased local efficacy while at the same time reducing the risk of bleeding. We evaluated the effect of nebulized tissue factor pathway inhibitor (TFPI), APC or AT on pulmonary coagulopathy and inflammation in a rat model of Streptococcus pneumoniae pneumonia. DESIGN: Randomized controlled in vivo study in a rat model of S. pneumoniae pneumonia. Twenty–eight male Sprague–Dawley rats were challenged intratracheally with S. pneumoniae (serotype 3, 106 colony forming units), inducing pneumonia. Rats were randomized to nebulization with TFPI, APC, AT or normal saline. RESULTS: Rats infected with S. pneumoniae had increased pulmonary and systemic levels of thrombin–antithrombin complexes (TATc) and fibrin degradation products (FDP), indicating increased coagulation. Simultaneously, pulmonary plasminogen activator inhibitor 1 (PAI–1) activity was increased and plasminogen activator activity (PAA) was reduced, indicating inhibition of endogenous fibrinolysis. Treatment with any nebulized natural anticoagulant significantly attenuated the rise in bronchoalveolar TATc (3.5 ± 0.9 ng/mL (TFPI), 3.6 ± 0.6 ng/mL (APC) and 4.6 ± 0.6 ng/mL (AT) versus 9.1 ± 0.75 ng/mL in saline treated rats, P
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology
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  • 6
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    Pharmacokinetics, Clinical Efficacy and Safety of Plasma-Derived Nanofiltered C1 Inhibitor Concentrate for Treatment of Hereditary and Acquired Angioedema. (2008)
    American Society of Hematology
    Details
    Publication Date: 2008-11-16
    Description: RATIONALE: From the early 70’s, C1 inhibitor concentrate manufactured from pooled human plasma has been available to patients with hereditary and acquired angioedema (HAE and AAE) and in 1997 a highly purified C1 inhibitor (Cetor®) was introduced. Many precautions have been taken to minimize the potential risk of viral transmission (e.g. rigorously controlled whole blood collection systems, extensive screening of each individual donation for a variety of blood-borne viruses, pasteurisation). To further minimize the potential risk of viral transmission, a 15 nm filtration was implemented in the manufacturing process giving rise to C1-inhibitor-N (anofiltered). DESIGN: A randomised, double-blind, controlled cross-over phase II study was conducted in which our primary objective was to compare the pharmacokinetics of the newly developed concentrate with conventional C1-inhibitor concentrate in HAE patients without signs of an attack of angioedema. Secondly, an open-label phase III study in patients with an HAE attack was performed to investigate whether the introduction of the virus reducing 15nm filtration step in the manufacturing process of the concentrate did not affect the efficacy and safety of the product. RESULTS: Thirteen patients were enrolled in the phase II study. No differences between conventional C1-inhibitor concentrate and nanofiltered C1-inhibitor concentrate were detected with regard to the primary pharmacokinetic parameters clearance, volume of distribution, and the fraction of C1-inhibitor-N detected by the antigen assay relative to the functional assay. Therefore incremental recovery, mean residence time, half-life and the area under curve were equivalent for both products. In the phase III study, 8 HAE patients were enrolled. In these 8 patients, 14 attacks qualified as acute angioedema attack. The mean time-to-relief for attacks treated with new C1-inhibitor concentrate was 3.0 (SD 2.5) hours. Historical data showed that treatment with conventional C1-inhibitor concentrate resulted in time-to-relief of 3.9 (SD 6.2) hours, whereas for untreated attacks this was 24.7 (SD 19.9) hours. The attacks treated with new C1-esterase inhibitor concentrate had a mean time-to-resolve of 18.6 hours (SD 13.1) whereas medical history showed an time-to-resolve of 17.8 hours (SD 17.2) for conventional C1-inhibitor. Untreated attacks showed a mean time-to-resolve of 63.6 hours (SD 31.0). CONCLUSION: The newly developed nanofiltered C1-esterase inhibitor has equal pharmacokinetic properties compared to the conventional concentrate. The viral reduction step (15 nm filtration) in the production process of Cetor did not induce changes in the efficacy and safety in the treatment of acute angioedema attacks and in the pharmacokinetic parameters.
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology
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