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681.
682.
Preet M. Singh Katherine Reid Ravindra Gaddam Madhav Bhatia Stefan Smith Antony Jacob Paul Chambers 《Veterinary anaesthesia and analgesia》2017,44(5):1149-1155
Objective
To determine the anti-inflammatory efficacy of choline in vivo and in vitro and to investigate the anti-inflammatory mechanisms of choline.Study design
Randomized, controlled studies.Animals
In vivo trials used 16 Romney sheep. In vitro experiments utilized RAW 264.7 mouse macrophage cells.Methods
Hypoxaemia induced in 16 sheep by intravenous (IV) injection of 50 μg kg–1 xylazine, an α-2 agonist, was measured in sheep at 0, 1 and 4 minutes using arterial blood gas analysis with and without 50 mg kg–1 IV choline chloride premedication. Cell culture studies used enzyme-linked immunosorbent assay to measure the release of tumour necrosis factor (TNF-α) from lipopolysaccharide (LPS) stimulated macrophages with and without choline chloride premedication. TNF-α release was compared to thalidomide suppressed and untreated cells.Results
Choline premedication in sheep mitigated a reduction in arterial partial pressure of oxygen (PaO2) but did not prevent development of clinically significant hypoxaemia. Decrease in mean PaO2 of choline treated sheep was 6.36 kPa (47.7 mmHg) compared to 9.81 kPa (73.6 mmHg) in control sheep. In vitro studies demonstrate that choline administered concurrent with LPS activation did not significantly suppress TNF-α expression but that treatment of cells with choline 10 minutes prior to LPS activation did significantly suppress TNF-α expression. Choline pretreated cells expressed 23.99 ± 4.52 ng mg–1 TNF-α while LPS only control cells expressed 33.83 ± 3.20 ng mg–1.Conclusions
Choline is able to prevent macrophage activation in vitro when administered prior to LPS activation and may reduce hypoxaemia in sheep developing pulmonary oedema after xylazine administration. This effect requires premedication with choline.Clinical relevance
Pharmacological manipulation of autonomic inflammatory responses holds promise for the treatment of inflammation. However, the complex cellular mechanisms involved in this reflex means that an adequate therapy should approach multiple pathways and mechanisms of the inflammatory response. 相似文献683.
Pedro Mondaca Alexander Neaman Sébastien Sauvé Eduardo Salgado Manuel Bravo 《植物养料与土壤学杂志》2015,178(3):452-459
We studied the fate of Cu in contaminated semiarid soils from two areas with different mining activities in central Chile. Several regression models were evaluated to use soil physicochemical characteristics to predict solubility, partitioning, and activity of Cu. Furthermore, we hypothesize that the type of Cu mining compound (smelter dust versus tailing sand) can be another important variable determining the bioavailability of Cu. In the studied neutral to alkaline soils, soil organic matter (SOM) enhanced Cu solubility most probably through the formation of organic complexes with dissolved organic C (DOC). As a consequence, Cu solubility and partitioning were better explained by DOC concentration than by SOM content. On the other hand, Cu activity was mainly related to soil pH and was not affected by DOC. Although we found differences between the two study areas, Cu solubility and partitioning might not be as dependent upon the origin of the Cu mining compound as upon other physiochemical characteristics that influence the concentration and characteristics of DOC. Total Cu, pH, and DOC would be the most important variables to consider on Cu solubility, however, data about the nature of SOM may certainly improve the prediction models. Thus, multiple binding site models between Cu and DOC should be studied to improve predictions of Cu solubility. 相似文献
684.
685.
The effect of the supply of ammonium (NH4 +) and phosphorus (P) in gel on the amounts of hydrogen ion (H+) excreted from plant roots was studied with Brachiaria humidicola (a highly acid‐soil tolerant tropical grass) and B. brizantha (less acid‐soil tolerant) grown in soil in a glasshouse. The H+ production was measured over 24 h in agar gel containing full nutrient solution with a range of NH/‐N levels (0, 0.25, 0.5, and 5.0 mM NH4 +‐N). Highly soluble P, K2HPO4, or relatively insoluble P, rock P, was supplied at four concentrations (0, 11.5, 34.5, or 115 μM p) in the gel. Increasing NH4 + concentration in the gel increased H+ production for both grasses, but there was some inhibition of growth for B. brizantha at the highest N concentration. For B. humidicola, but not B. brizantha H+ production was greater with 34.5 μM K2HPO4 than 11.5 μM K2HPO4. At 34.5 μM P for both grasses there was no difference in H+ production when P was supplied as rock P or K2HPO4. With 11.5 μM P both grasses produced less acid in the gel with the rock P compared with K2HPO4. The reduced H+ production is probably due to a lower availability of P in the rock P compared with K2HPO4. This effect was greater with B. brizantha than B. humidicola, implying that 11.5 μM rock P was not able to supply sufficient P for the growth of B. brizantha. Brachiaria humidicola was able to dissolve more rock P than B. brizantha or alternatively, the growth of B. humidicola was less adversely affected by the low P supply from rock P than B. brizantha. Plant‐induced acidity does not seem to occur as a response to a lack of available P, but rather these grasses only produce acid if there are enough nutrients for growth, i.e., both NH4 + and P. If either N or P is limiting, growth is limited as is NH4 + uptake, so that H+ production is curtailed. 相似文献
686.
Sharpless KE Phinney CS Wood LJ Yen JH Howell DW 《Journal of agricultural and food chemistry》2003,51(23):6745-6751
Standard Reference Material (SRM) 2387 peanut butter was recently issued, and the process used for value assignment of nutrient and aflatoxin concentrations is reported herein. Values were assigned using data provided by the National Institute of Standards and Technology (NIST) and collaborating laboratories. SRM 2387 is intended for use as a primary material for assigning values to in-house control materials and for validation of analytical methods for measurements in peanut butter and similar high-fat matrixes. SRM 2387 lies in sector 3 of AOAC International's fat-protein-carbohydrate triangle. With the addition of SRM 2387, NIST now offers materials within-or on the borders between-all sectors of the triangle. The Certificate of Analysis for SRM 2387 provides assigned values for concentrations of fatty acids, proximates, elements, and total dietary fiber, for which product labeling is required by the Nutrition Labeling and Education Act of 1990, as well as several vitamins, amino acids, and aflatoxins, for which labeling is not required. (Aflatoxin levels in peanut butter are regulated by the Food and Drug Administration.) 相似文献
687.
R. Kelman Wieder Katherine P. Heston Ellen M. O'Hara Gerald E. Lang Alfred E. Whitehouse Jack Hett 《Water, air, and soil pollution》1988,37(1-2):177-191
Runoff from a highway interchange in western Maryland had Al concentrations averaging about 50 mg L?1, with a maximum of 206 mg L?1. As an alternative to expensive chemical treatment of this Al-rich water, in August 1984, the drainage was diverted through a 500 m2 man-made wetland, constructed from organic peat. For a 10 week period, Al concentrations in water leaving the wetland averaged 1.5 mg L?1. as compared to Al concentrations at the two major inflows to the wetland of 35.3 and 6.6 mg L?1. However, effective treatment of the drainage by the wetland was not observed over the entire 27 mo sampling period. Peat chemical analysis indicated that over the 27 mo, total Al concentration in the peat increased from 2375 μg g?1 to 13 634 μg g?1. Of this increase 5.5 % was contributed by exchangeable Al, 4.3% by adsorbed Al, 39.8% by organically bound Al, 33.1% by oxide bound Al, and 17.2% by precipitated and residual Al. Changes in Fe, Mn, Ca, Mg, K, and Na chemistry in the peat associated with Al retention are discussed. 相似文献
688.
In order to extend the use of the Rapid Visco Analyser (RVA) as an analytical tool in barley breeding programs, it is necessary to find relationships between barley flour pasting properties and potential malting quality. Traditionally, the RVA is used to provide discrete values related with the pasting characteristics of the sample under analysis. Although this approach is very useful, considering the rich data generated by RVA analysis, this can result in the loss of information about starch pasting characteristics, reducing the potential of the RVA as an analytical tool. This study aims to evaluate the ability of using multivariate data methods (MVA) and derivatives to the profile generated by the RVA as a source of information to further study starch pasting characteristics to select materials in barley breeding programs or other food applications. The use of MVA techniques such as principal component analysis (PCA) and partial least squares (PLS) regression together with the use of derivatives (e.g. first and second derivatives) allows better interpretation of the RVA profile, resulting in more information related to the pasting properties of the sample. 相似文献
689.
Katherine E. L. Worsley‐Tonks Elizabeth A. Miller Stanley D. Gehrt Shane C. McKenzie Dominic A. Travis Timothy J. Johnson Meggan E. Craft 《Zoonoses and public health》2020,67(4):460-466
The role of wildlife in the dissemination of antimicrobial‐resistant bacteria and antimicrobial resistance genes (ARGs) in the environment is of increasing concern. We investigated the occurrence, richness and transmissibility potential of ARGs detected in the faeces of three mesocarnivore species: the coyote (Canis latrans), raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana), and of stray and owned dogs in suburban Chicago, IL, USA. Rectal swabs were collected from live‐captured coyotes (n = 32), raccoons (n = 31) and Virginia opossums (n = 22). Fresh faecal samples were collected from locally owned (n = 13) and stray dogs (n = 18) and from the live‐captured mesocarnivores, when available. Faecal samples and rectal swabs were enriched to select for Enterobacteriaceae and pooled by mesocarnivore species and dog type (owned or stray). Pooled enriched samples were then analysed for the presence of ARGs using shotgun sequencing. The three mesocarnivore and stray dog samples had twice as many unique ARGs compared to the owned dog sample, which was partly driven by a greater richness of beta‐lactamase genes (genes conferring resistance to penicillins and cephalosporins). Raccoon and stray dog samples had the most ARGs in common, suggesting possible exposure to similar environmental sources of ARGs. In addition to identifying clinically relevant ARGs (e.g. blaCMY and qnrB), some ARGs were linked to the class 1 integrase gene, intI1, which may indicate anthropogenic origin. Findings from this pilot investigation suggest that the microbial communities of suburban mesocarnivores and stray dogs can host ARGs that can confer resistance to several antimicrobials used in human and veterinary medicine. 相似文献
690.
Anthony F. Hamnett Anthony P. Ottridge Grahame E. Pratt Richard C. Jennings Katherine M. Stott 《Pest management science》1981,12(3):245-254
The hydrolysis of 3, 4-dihydroprecocene I 3, 4-epoxide (3, 4-dihydro-7-methoxy-2, 2-dimethyl-3, 4-epoxy-2H-benzo[b]pyran), the putative ultimate cytotoxin of the insect growth regulator precocene I (7-methoxy-2, 2-dimethyl-2H-benzo[b]pyran), has been studied and found to exhibit first-order kinetics [k = 0.17 s?1 in 10 mm-phosphate buffer pH 7.0, containing 1, 4-dioxane (1 + 1 by volume), ionic strength 0.1]. Plots of log k versus pH, and k versus buffer concentration, suggest that the reaction is subject to both specific and general acid catalysis. High-performance liquid chromatography showed the reaction products to be predominantly the corresponding stereoisomeric diols (3, 4-dihydro-7-methoxy-2, 2-dimethyl-2H-benzo[b]pyran-3, 4-diol), the trans : cis ratio of which varied from 1.8: 1 to 2.2: 1 but was constant over the pH range 6-8, at a given buffer concentration. The results indicate that acid-catalysed hydration of 3, 4-dihydroprecocene I 3, 4-epoxide is an SN1 reaction, involving a trigonally hybridised carbocation at C4, even at physiological pH. Similar studies on 3, 4-dihydroiso-precocene I 3, 4-epoxide (3, 4-dihydro-6-methoxy-2, 2-dimethyl-3, 4-epoxy-2H-benzo-[b]pyran), a biologically inactive isomer of 3, 4-dihydroprecocene I 3, 4-epoxide suggest that an SNI mechanism also contributes to its hydrolysis, but the rate constant is 4000 times lower than that for 3, 4-dihydroprecocene I 3, 4-epoxide. Knowledge of the reactivity and mechanism of reaction of such compounds forms an important part of the basis for rational prediction of biological activity in precocene analogues, and hence their possible use as pest control agents. 相似文献