In vitro expression and inhibition of procoagulant activity produced by bovine alveolar macrophages and peripheral blood cells     

J. Rashid  D. J. Weiss  S. K. Maheswaran  M. P. Murtaugh 《Veterinary research communications》1996,20(6):519-531

Local and systemic activation of coagulation is frequently associated with bacterial sepsis. The coagulopathy is due, at least in part, to expression of tissue factor (TF) by monocytes and macrophages. The purpose of this study was to evaluate the expression of procoagulant activity by bovine alveolar macrophages, leukocytes and platelets, and to determine the relative potency of three chemical inhibitors of TF expression (pentoxifylline, retinoic acid, and cyclosporin A). Bovine alveolar macrophages were stimulated with lipopolysaccharide (LPS) derived from Pasteurella haemolytica or recombinant bovine tumour nervous factor (TNF) and dose- and time-dependent effects on TF expression were studied. LPS and TNF induced TF expression in alveolar macrophages and LPS treatment of whole blood induced TF expression in mononuclear cells. Neutrophils and platelets also expressed procoagulant activity, but this activity was not inhibited by anti-bovine TF monoclonal antibody. Pentoxifylline (40 mol/L), retinoic acid (0.01 mmol/L) and cyclosporin A (0.08 mol/L) inhibited TF expression when added concurrently with LPS or TNF, but not when added 4 h after stimulation. TF mRNA was not detected in unstimulated alveolar macrophages by Northern blot analysis. In contrast, exposure to LPS or TNF for 6 h induced marked expression of TF mRNA, which was inhibited by treatment with pentoxifylline, retinoic acid and cyclosporin A. Expression of TNF by alveolar macrophages stimulated with LPS was also inhibited by these compounds. Our results indicate that procoagulant activity expressed by alveolar macrophages and monocytes is associated with expression of TF, whereas procoagulant activity expressed by neutrophils and platelets is not. The concentrations of pentoxifylline and retinoic acid necessary for inhibition of TF expression in vitro may not be achievable in vivo owing to their toxic effects. However, the in vitro concentration of cyclosporin A that inhibited TF expression did not exceed the plasma concentration observed in humans, and therefore may be useful for inhibition of TF expression in vivo.Abbreviations BAL bronchoalveolar lavage - LPS lipopolysaccharide - cDNA cloned deoxyribonucleic acid - cAMP cyclic adenosine monophosphate - GAPDH glyceraldehyde phosphate dehydrogenase - mRNA messenger ribonucleic acid - TF tissue factor - TNF tumour necrosis factor - DPBS Dulbecco's phosphate-buffered saline  相似文献   

Eperythrozoonisis in a one-day-old llama     

Fisher DJ  Zinkl JG 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1996,25(3):93-94

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Relationship of plasma lactate production to cortisol release following completion of different types of sporting events in horses     

D. Desmecht  A. Linden  H. Amory  T. Art  P. Lekeux 《Veterinary research communications》1996,20(4):371-379

Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n=6), cross-country in a three-day event (n=30), trotting races (n=7), galloping reces (n=7) and endurance rides (n=8). Venous blood samples were collected at rest and immediately after exercise and analysed for plasma cortisol (CORT) and lactate (LA) levels. The experimental procedure was the same throughout the investigation so as to permit a reliable comparison between the five types of exercise. The type of event significantly affected both the resting (p0.05) and the postexercise (p0.01) plasma CORT. The degree of exercise-induced hypercortisolaemia was related to both the intensity and the duration of exercise for all five sporting events, but the endurance ride induced the most and show-jumping the least serious post-exercise CORT changes. LA production was much more closely related to the intensity of the exercise than was CORT. It is concluded that simultaneous measurements of plasma CORT and LA levels may be useful to discriminate between different types of exercise, adjust training programmes, and improve our comprehension of the physiology of sport horses at exercise.Abbreviations CORT cortisol - E/R exercise to rest ratio - EDTA ethylenediaminetetraacetic acid - HR heart rate - LA lactate  相似文献   

Development of equine veterinary medicine in the United States     

Proctor DL 《Veterinary heritage : bulletin of the American Veterinary History Society》1996,19(2):33-34

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The idea of chemistry     

Barkan D 《Science (New York, N.Y.)》1994,265(5171):551-552

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Trying to continue research on a wing and a prayer     

Clery D 《Science (New York, N.Y.)》1994,264(5163):1271-1273

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A once-favored discipline has the furthest to fall     

Clery D 《Science (New York, N.Y.)》1994,264(5163):1268-1270

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Molluscan dwellings     

Saunders WB 《Science (New York, N.Y.)》1994,264(5156):295-296

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A formation mechanism for catalytically grown helix-shaped graphite nanotubes     

Amelinckx S  Zhang XB  Bernaerts D  Zhang XF  Ivanov V  Nagy JB 《Science (New York, N.Y.)》1994,265(5172):635-639

The concept of a spatial-velocity hodograph is introduced to describe quantitatively the extrusion of a carbon tubule from a catalytic particle. The conditions under which a continuous tubular surface can be generated are discussed in terms of this hodograph, the shape of which determines the geometry of the initial nanotube. The model is consistent with all observed tubular shapes and explains why the formation process induces stresses that may lead to "spontaneous" plastic deformation of the tubule. This result is due to the violation of the continuity condition, that is, to the mismatch between the extrusion velocity by the catalytic particle, required to generate a continuous tubular surface, and the rate of carbon deposition.  相似文献   

Book reviews     

D. W. Burt  J. M. McNab 《British poultry science》1994,35(1):189-191

Manipulation of the Avian Genome. Edited by R. J. Etches & A. M. V. Gibbins, 1993. 322 pp., illustrated in colour. Boca Raton, FL, CRG Press. ISBN 0–8493–4216–3.

Proceedings of the 8th European Symposium on Poultry Nutrition. Edited by The Organizing Committee, 1992. 373 pp. Milan, Italy. World's Poultry Science Association.  相似文献