Platelet activating factor as a mediator of equine cell locomotion     

J. Dawson  P. Lees  A. D. Sedgwick 《Veterinary research communications》1988,12(2-3):101-107

Equine polymorphonuclear (PMN) and mononuclear (MN) leucocytes were separated on Percoll gradients and used to study the chemoattractant properties of the polar ether-linked phospholipid, platelet activating factor (PAF). Six concentrations of PAF ranging from 1 ng/ml to 100 g/ml were studied in each of two in vitro assay systems, the agarose microdroplet and a microfilter technique. Very significant (p<0.01) increases in the movement of both PMN and MN cells were obtained with most concentrations of PAF. In two instances there was no apparent concentration-response relationship, although the action of PAF was approximately bell-shaped in two others. The possible significance of these findings for equine inflammatory conditions is discussed.  相似文献   

Escherichia coli sepsis and endotoxemia in conscious young pigs     

E. Schrauwen  E. Cox  A. Houvenaghel 《Veterinary research communications》1988,12(4-5):295-303

In conscious pigs the influence of intravenous infusion of live E. coli (7×10⁸/kg), of the equivalent amount of endotoxin (20 g/kg) or of a high dose of endotoxin (2.5 mg/kg) on the hemodynamic, clinical and pathological parameters and on survival rate was studied. E. coli and endotoxin infusion resulted in pulmonary hypertension, systemic arterial hypotension, a decrease in cardiac output and an increase in heart rate. Clinical signs were characterized by respiratory and nervous disturbances, whereas necropsy revealed hemorrhages and edema in several organs. Although these findings were similar in the three groups, a marked difference in lethality was observed. Infusion of E. coli or of the high dose of endotoxin resulted in a significant mortality, whereas all pigs survived the infusion of the low dose of endotoxin. This suggests that the lethal pathophysiological mechanisms may only become activated when a sufficient amount of endotoxin is released into the circulation.  相似文献   

Bovine and canine acute phase proteins   总被引：1，自引：0，他引：1  

P. D. Eckersall  J. G. Conner 《Veterinary research communications》1988,12(2-3):169-178

Acute phase proteins are serum proteins which increase in concentration during the acute phase response to inflammation or infection. The response occurs in all animals, but in different species the response of individual proteins can be significantly different. Of the numerous acute phase proteins which have been identified in humans, a number have been examined in cattle and dogs but usually on an individual basis with little reference to their part in the acute phase response. Biochemical, physiological and clinical investigations into haptoglobin, fibrinogen, ₁-proteinase inhibitor, ceruloplasmin, seromucoid and C-reactive protein of cattle and dogs have therefore been reviewed with the emphasis on their role in this response to tissue damage.  相似文献   

Some Other Books of Interest: The Earth's Fragile Systems     

W DF 《Science (New York, N.Y.)》1988,241(4872):1519

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Pay Cap for Grantees Has Up Side for NSF     

W J 《Science (New York, N.Y.)》1988,241(4870):1159

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Volcanic rocks: mantle xenoliths     

Shervais JW 《Science (New York, N.Y.)》1988,241(4863):366-367

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Science and technology awards     

Trivelpiece AW 《Science (New York, N.Y.)》1988,241(4869):1025

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Effects of Acid rain on freshwater ecosystems   总被引：1，自引：0，他引：1  

Schindler DW 《Science (New York, N.Y.)》1988,239(4836):149-157

Acid-vulnerable areas are more numerous and widespread than believed 7 years ago. Lakes and streams in acid-vulnerable areas of northeastern North America have suffered substantial declines in acid-neutralizing capacity, the worst cases resulting in biological damage. Many invertebrates are very sensitive to acidification, with some disappearing at pH values as high as 6.0. However, the recent rate of acidification of lakes is slower than once predicted, in part the result of decreases in sulfur oxide emissions. A discussion of some of the processes that have contributed to the acidification of lakes as well as those that have protected acid-sensitive freshwaters is presented. The author is in the Department of Fisheries and Oceans, Freshwater Institute, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada.  相似文献   

NSF Appoints Two Assistant Directors     

W J 《Science (New York, N.Y.)》1988,240(4855):980

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Olmec settlement data from la venta, tabasco, Mexico     

Rust WF  Sharer RJ 《Science (New York, N.Y.)》1988,242(4875):102-104

Research at La Venta, a major Olmec center on a low salt dome 12 kilometers from the Gulf Coast has revealed evidence of initial occupation (about 1750 to 1400 B.C.) along levees of the silted-in Río Barí, north of the site core in a transitional estuarine-riverine environment. Between 1400 and 1150 B.C. settlement expanded to nearby La Venta itself, which between 1150 and 800 B.C. developed into a major temple-town complex. Local development peaked at La Venta and along the river levees between 800 and 500 B.C. In this span La Venta headed a local three-tiered site hierarchy as social distinctions expanded to the peripheral Río Barí sites. New excavations show that growth in population size and density at La Venta preceded the development of sociopolitical complexity. These data contradict the traditional organizational reconstruction of Olmec society, the "vacant ceremonial center" model, and provide qualified support for a model that presents riverine resource concentration as a significant factor in the evolution of Olmec civilization.  相似文献