Evaluation of leukotriene biosynthetic capacity in lung tissues from horses with recurrent airway obstruction     

Lindberg A  Näsman-Glaser B  Lindgren JA  Robinson NE 《American journal of veterinary research》2002,63(6):794-798

OBJECTIVE: To evaluate leukotriene (LT) biosynthetic capacity in lung tissue from healthy horses and horses with recurrent airway obstruction (RAO). SAMPLE POPULATION: Lung parenchyma and airway specimens from 8 RAO-affected and 5 healthy horses. PROCEDURE: Horses were stabled for > or = 72 hours. Blood was drawn before euthanasia, after which lung specimens were collected. Tissue strips from small airways and parenchyma were incubated in organ baths with the precursor LTA4 or stimulated with calcium ionophore A23187 or the tripeptide N-formyl-Met-Leu-Phe (fMLP), with or without exogenous arachidonic acid, in the presence of isolated blood neutrophils. RESULTS: Stabling induced typical clinical signs of airway obstruction in RAO-affected horses but not control horses. When lung parenchyma or airway specimens from both groups of horses were incubated with calcium ionophore, with or without arachidonic acid, they did not form LT. In contrast, addition of LTA4 to both tissues resulted in conversion to LTB4, although concentrations of LTC4 were negligible in airways and parenchymal strips from healthy and RAO-affected horses. Incubation of airway and parenchymal strips with suspensions of autologous neutrophils did not influence formation of LT stimulated by calcium ionophore or fMLP, with or without exogenous arachidonic acid. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lung parenchyma and airway tissues themselves are not of substantial importance for LT formation in the lungs, although these tissues possessed some LTA4 hydrolase activity, enabling LTB4 formation. It may be speculated that LTB4 originates primarily from neutrophils and may play a role in the inflammatory events of RAO.  相似文献   

Probing cold dense nuclear matter     

Subedi R  Shneor R  Monaghan P  Anderson BD  Aniol K  Annand J  Arrington J  Benaoum H  Benmokhtar F  Boeglin W  Chen JP  Choi S  Cisbani E  Craver B  Frullani S  Garibaldi F  Gilad S  Gilman R  Glamazdin O  Hansen JO  Higinbotham DW  Holmstrom T  Ibrahim H  Igarashi R  de Jager CW  Jans E  Jiang X  Kaufman LJ  Kelleher A  Kolarkar A  Kumbartzki G  Lerose JJ  Lindgren R  Liyanage N  Margaziotis DJ  Markowitz P  Marrone S  Mazouz M  Meekins D  Michaels R  Moffit B  Perdrisat CF  Piasetzky E  Potokar M  Punjabi V  Qiang Y  Reinhold J  Ron G 《Science (New York, N.Y.)》2008,320(5882):1476-1478

The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.  相似文献   

Leukotrienes and lipoxins: structures, biosynthesis, and biological effects   总被引：94，自引：0，他引：94  

B Samuelsson  S E Dahlén  J A Lindgren  C A Rouzer  C N Serhan 《Science (New York, N.Y.)》1987,237(4819):1171-1176

Arachidonic acid is released from membrane phospholipids upon cell stimulation (for example, by immune complexes and calcium ionophores) and converted to leukotrienes by a 5-lipoxygenase that also has leukotriene A4 synthetase activity. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. Lipoxins are formed by the action of 5- and 15-lipoxygenases on arachidonic acid. Lipoxin A causes contraction of guinea pig lung strips and dilation of the microvasculature. Both lipoxin A and B inhibit natural killer cell cytotoxicity. Thus, the multiple interaction of lipoxygenases generates compounds that can regulate specific cellular responses of importance in inflammation and immunity.  相似文献   

Behaviour of sulphur and nitrogen compounds measured at marine stations Lista and Säby in Scandinavia     

J. Isakson  E. A. Selin Lindgren  V. L. Foltescu  J. M. Pacyna  K. Tørseth 《Water, air, and soil pollution》1995,85(4):2039-2044

Long distance transport of various air pollutants has been studied at two Scandinavian coastal sites. The measuring period has covered one year divided into 4 campaigns. Seasonal variations for sulphur and nitrogen compounds as well as anthropogenically emitted metals are reported. Concentrations of Pb and Zn as well as the ratio of V/Ni concentrations have been used to trace sulphuric episodes. Covariation of anthropogenic pollutants for the two sites is demonstrated.  相似文献   

Benefits and risks of barefoot harness racing in Standardbred trotters     

Marina Sol  Gabriella Lindgren  Erik Bongcam‐Rudloff  Anna Jansson 《Animal Science Journal》2020,91(1)

There is a lack of research on the benefits and risks of shoeing conditions in harness racing. Thus, our objectives were to: (a) investigate whether velocity times (VT; s/km) are affected by racing unshod (N = 76,932 records on 5,247 horses); (b) determine the potential risks of galloping, being penalized, and disqualification when competing unshod (N = 111,755 records on 6,423 horses); and (c) identify additional environmental factors that affect VT and risks. VT was found to be significantly influenced by shoeing condition (e.g., unshod, shod front, shod hind, or fully shod), but also by sex, age, season, track, track condition, start method, start position, distance, and driver‐horse performance level (p < 2e‐16). The risks of galloping and disqualification were significantly influenced by shoeing condition, sex, age, season, track, start method, start position, or driver‐horse performance level (p ≤ .05). Horses racing unshod had 0.7 s/km lower VT than fully shod horses and showed better performance when racing on neutral tracks during the late summer than horses with other shoeing conditions during the same period. However, racing unshod increased the relative risks of galloping and disqualification by 15%–35% in all seasons. Horses shod only on the hind hooves showed better performance than fully shod horses, without higher risks associated with competing unshod.  相似文献   

The expression of intermediate filaments in canine mammary glands and their tumors   总被引：3，自引：0，他引：3  

E Hellmén  A Lindgren 《Veterinary pathology》1989,26(5):420-428

Monoclonal antibodies specific for different types of intermediate filaments (cytokeratin, vimentin, desmin and neurofilaments) were used to study the histogenesis of canine mammary glands and 57 canine mammary tumors by immunocytochemistry. The intra- and interlobular duct epithelium, acinar, and intralobular myoepithelial cells stained positively for cytokeratin. Peripheral ductal and acinar cells, as well as interstitial cells, stained positively for vimentin. A similar staining pattern was seen in adenomas, complex adenomas, benign mixed tumors, ductular carcinomas, and one myoepithelioma-like tumor. Additionally, cytokeratin positive cells were scattered interstitially in one single adenoma, most complex adenomas, some benign mixed tumors, complex carcinomas, and in the malignant mixed tumors. All stromal cells stained positively for vimentin. The fibrosarcomas were positive only for vimentin, while the following expressed both desmin and cytokeratin: epithelial-like cells in one adenoma, three complex adenomas, the myoepithelioma-like tumor, the single comedo carcinoma, two complex carcinomas, the single lobular carcinoma, one malignant mixed tumor, and three osteosarcomas. Epithelial-like cells in one adenoma, six complex adenomas, two benign mixed tumors, two complex carcinomas, the lobular carcinoma, and the malignant schwannoma stained for neurofilaments. Three tumors, one adenoma, one complex adenoma, and the lobular carcinoma expressed both desmin and neurofilaments in addition to cytokeratin and vimentin. The results show the expression of different types of intermediate filaments and indicate that there might be a stem cell origin in most of the canine mammary tumors.  相似文献   

Can predicted mountain pine beetle net production be used to improve stand prioritization for management?     

Niklas Björklund  B. Staffan Lindgren  Terry L. Shore  Tim Cudmore 《Forest Ecology and Management》2009

Stand-level planning of lodgepole pine management can benefit from the use of mountain pine beetle susceptibility-risk model analyses to assign treatment priority. Priority is currently assigned based solely on relative levels of expected volume loss in the event of a mountain pine beetle outbreak. We evaluated the possibility to predict the relative contribution of brood beetles, by infested stands, to the next beetle generation. Existing data were used to develop generalized parameters for inclusion in predictive models of stand-level mortality and brood production. Model output for independent stands achieved a highly significant relationship with measured outcomes of brood productivity, indicating that relative levels of brood production can be predicted and incorporated into decision-models.  相似文献   

Variation in cone and seed characters in clonal seed orchards of <Emphasis Type="Italic">Pinus sylvestris</Emphasis>     

Nebi Bilir  Finnvid Prescher  Dag Lindgren  Johan Kroon 《New Forests》2008,36(2):187-199

Cone and seed characters were observed on top, middle and bottom portions of tree crown in 3 ramets/clone in three Turkish Pinus sylvestris seed orchards. Broad sense heritability (clonal repeatability), and correlations among characters were estimated. Around one quarter of the seed production occurred in the top portion, half in the middle and one quarter in the bottom portion of the crown for all orchards. The percentage of filled seeds varied little with the crown position, indicating more or less similar levels of selfing in the bottom of the crown as in the top. The seed weight was typically 11 mg. Differences were found for studied cone and seed characters among orchards and crown positions. Variation among grafts within clone was higher than among clones for most characters. The heritability was on average below 0.5 (e.g., cone diameter, number of filled seed per cone) and rarely rose above that (e.g., cone form, length/diameter; percentage of filled seed) for any individual characters. The coefficient of variation within clones was often higher than among clones. Thus, non-genetic factors seem often more important for the variation in performance of grafts than their genetic constitution. Cone form (length/diameter) was the character where the clone influence was the strongest. Cone number and cone dry weight showed significant correlations with seed characters (numbers of total and filled seed, percentage and weight of filled seeds). Significant correlation was found between seed characters.  相似文献   

Efficiency of breeding strategy where grandparents — but not parents — contribute equally to the breeding population     

Darius Danusevičius  Dag Lindgren 《Annals of Forest Science》2010,67(4):404-404

? The objective was to optimise the strategy for maintaining the genetic balance in long-term breeding where the grandparents contribute equally to the breeding population, but the parents do not.

? The annual genetic progress under a budget constraint was compared for a number of scenarios. The factors considered were: genetic parameters, recruitment population size, mating number per grandparent, cost of plants and parents, selection age and time components. Phenotypic selection forward was assumed. Using more parents than grandparents affects the testing population only, thus, gene diversity loss and breeding population size remain constant.

? Using larger number of parents than grandparents was a superior strategy at all scenarios tested. The strategy with 6 parents per grandparent and 1% of the tested plants selected on their phenotype at age 15 for further mating is recommendable. The strategy to choose 6 parents per grandparent was robust over a heritability range 0.05 to 0.2. At a higher heritability, the optimum number of parents per grandparent was 2 to 4.

? Using larger number of parents than grandparents has the potential to improve annual genetic gain in the magnitude of 50% compared to the strategies currently used for Scots pine in Sweden.

  相似文献   

A 60-years old field experiment demonstrates the benefit of leys in the crop rotation     

Zhenjiang Zhou  Cecilia Palmborg  Lars Ericson  Kent Dryler  Kim Lindgren  Göran Bergkvist 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(1):36-42

In the 1950s, a long-term experiment was initiated at three locations in Northern Sweden. The treatments included four cropping systems, which differed in the number of years with leys or annual crops in the crop rotation. To create awareness of the experiment as a research resource for further scientific studies, we summarise the history (experimental design, materials and methods, main measurements) and scientific findings of the experiment, as well as reflect on its usefulness and opportunities for further studies. So far, scientific focus has been on the effects of cropping systems on soil characteristics. The main findings indicate that soil porosity and hydraulic conductivity were greater in cropping systems with a large proportion of ley, soil bulk density showed the opposite trend. In terms of chemical properties, cropping systems incorporating more ley also have greater soil organic carbon content than annual crops systems, and both soil carbon and N storage decrease over time in cropping systems with only annual crops. The effects of cropping system on crop yields and quality are areas for further investigation.  相似文献