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, such as that seen in progressive joint disease. 6 Osteoclast development and activation depend on a system comprising RANK, RANKL, and OPG. A membrane-bound tumor necrosis factor superfamily ligand, RANKL, can be released from cells after cleavage by

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in American Journal of Veterinary Research

activation as part of the respiratory burst, and because the MPO index estimates the intracellular content of MPO per neutrophil, decreases in MPO index are thought to occur secondary to neutrophil degranulation. 6 The stage of the myelopoietic response to

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in American Journal of Veterinary Research

of septic joints with MSCs activated with the TLR-3 agonist polyinosinic:polycytidylic acid (pIC) plus vancomycin (TLR-MSC-VAN) significantly reduced quantitative bacterial counts in synovial fluid and synovium as well as the proinflammatory cytokines

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in Journal of the American Veterinary Medical Association

Moreover, addition of exogenous IL-10 or TGF-β to bovine monocytes permits greater proliferation of Mptb organisms. 9 Three subfamilies of MAPK, including JNK/SAPK, ERK-1 and -2, and p38, are described. 10–12 The MAPK pathway is activated by several

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in American Journal of Veterinary Research

SUMMARY

The activation of the complement system of rainbow trout by trout C-reactive protein (crp) was investigated. Complement fixation tests were performed by using rabbit hemolysin-sensitized sheep erythrocytes and rainbow trout complement. Purified crp increased the consumption of complement in the presence of Streptococcus pneumoniae C-polysaccharide (cps), indicating the activation of the complement system. In contrast to this, acute phase serum activated the complement in the absence of cps. Consumption of the complement by acute-phase serum was depressed when crp was removed from acute-phase serum by cps-sepharose 4B affinity chromatography. The acute-phase serum, as well as crp plus cps, suppressed in vitro growth of Vibrio anguillarum in the presence of complement, and enhanced the phagocytosis of the bacteria by glass-adherent peritoneal exudate cells. These results indicated that crp has a role in host defense during acute-phase response through the activation of the complement system, enhancement of phagocytosis, and suppression of bacterial growth.

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate lipopolysaccharide (LPS)- induced activation of equine neutrophils in blood.

Sample Population—Blood samples from 5 healthy adult Thoroughbreds.

Procedure—Neutrophil integrin (CD11/CD18) expression, size variation, degranulation, and deformability were measured with and without incubation with LPS. Time and concentration studies were done. The mechanism of endotoxin-induced neutrophil activation was investigated by inactivating complement or preincubating neutrophils with inhibitors of tumor necrosis factor-α (TNF-α) synthesis, prostaglandin-leukotriene synthesis, or plateletactivating factor.

Results—Incubation of equine neutrophils with LPS increased cell surface expression of CD11/CD18, decreased neutrophil deformability, increased and decreased neutrophil size, and induced neutrophil degranulation. The LPS-induced neutrophil activation was attenuated by addition of inhibitors of TNF-α and prostaglandin-leukotriene synthesis.

Conclusion and Clinical Relevance—Equine neutrophils are readily activated in vitro by LPS, resulting in increased expression of integrin adhesion molecules, decreased deformability, variation in neutrophil size, and degranulation. The tests used to detect activated neutrophils in this study may be useful in detecting in vivo neutrophil activation in horses with sepsis and endotoxemia. (Am J Vet Res 2002;63:811–815)

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in American Journal of Veterinary Research

those enzymes have in the metabolism, division, and proliferation of cancer cells. The AKT pathway is 1 pathway that can be targeted through kinase inhibition. The AKT pathway is activated in most melanomas of humans, and that activation is associated

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in American Journal of Veterinary Research

Abstract

Objectives

To investigate the role of extracellular Ca2+ and Mg2+ in aggregated IgG (algG)-mediated cellular activation, and to determine how algG-induced activation is coupled to Ca2+ homeostasis in bovine neutrophils.

Sample Population

4 clinically normal, lactating Holstein cows, in their second lactation, which ranged between 60 and 150 days.

Procedure

algG was prepared by heating bovine igG, and C5a was obtained by activating fetal bovine serum with zymosan. Luminol-amplified chemiluminescence (CL) of isolated neutrophils was measured in the presence of algG or phorbol 12-myristate 13-acetate (PMA). The reaction mixture contained either Hanks’ balanced salt solution or Ca2+- and Mg2+-free Hanks’ balanced salt solution. Binding of algG to neutrophils was measured by flow cytometry after incubation with fluorescein isothiocyanate-conjugated second antibody. Intracellular-free concentration [Ca2+] was measured in a fluorescence spectrofluorometer after incubation of neutrophils, loaded with the fluorescent dye fura-2 acetoxymethyl ester, with either algG or C5a.

Results

In a Ca2+- and Mg2+-containing reaction mixture, algG induced strong CL responses, whereas removal of extracellular divalent cations almost abolished the respiratory burst activity. The CL emission on stimulation with PMA was independent of extracellular Ca2+ and Mg2+. Examination of cells by flow cytometry after incubation with algG indicated that the binding of algG was identical in the presence and absence of extracellular Ca2+ and Mg2+. No increase in [Ca2+] was seen in fura-2 acetoxymethylester-loaded neutrophils after stimulation with algG. C5a induced a typical transient increase in [Ca2+].

Conclusions

algG-induced activation of bovine neutrophils is highly dependent on presence of extracellular divalent cations. This dependency is not caused by the need of divalent cations for binding of algG by neutrophils or because the influx of Ca2+ from the extracellular space is an integral component of algG-mediated activation pathway. Because need for extracellular Ca2+ and Mg2+ could be partially circumvented by pretreating neutrophils with PMA, it is possible that this activation pathway may involve a protein kinase C, which is not directly coupled to receptors for algG. (Am J Vet Res 1996;57:1312-1316)

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in American Journal of Veterinary Research

Summary

Fibrin clots were induced in eyes of dogs by injection of autogenous citrated plasma into the anterior chamber. Twenty-four hours after clot formation, 0.01 ml of tissue plasminogen activator at a concentration of 1 μg/100 μl (group 1, n = 5) or 25 μg/100 μl (group 2, n = 5) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Serial photographs were taken of the fibrin clots after intracameral injection of tissue plasminogen activator. Computerized morphometric analysis was then used to evaluate changes in cross-sectional surface area of the fibrin clot. Significant (P < 0.001) fibrin-clot lysis was detected in treated eyes of group-2 dogs, but was not found in treated eyes of group-1 dogs. A mean decrease of > 90% in clot surface area was detected by 120 minutes after injection in treated eyes of group-2 dogs.

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in American Journal of Veterinary Research

compromised pigs. Peroxisome proliferator-activated receptors, members of the nuclear hormone receptor superfamily, are ligand-activated transcription factors that include PPARα, PPARβ, and PPARγ 4 The PPARs regulate gene expression by binding (with the

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in American Journal of Veterinary Research