Glucocorticoids profoundly influence immune responses, and synthetic glucocorticoids are widely used clinically for their potent antiinflammatory effects. Endogenous glucocorticoid action is modulated by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD). In vivo, 11β-HSD1 catalyzes the reduction of inactive cortisone or 11-dehydrocorticosterone into active cortisol or corticosterone, respectively, thereby increasing intracellular glucocorticoid levels.
View Article and Find Full Text PDFThe roles of physician leaders in Canadian hospitals and health regions are becoming more complex and time consuming. Physician leaders are increasingly being seen by hospital boards and executives as key to achieving strategic and operational outcomes. Given the growing importance of these roles and the increasing performance expectations being placed on physician leaders, it is critical that organizations are able to recruit and retain individuals who demonstrate the skills required to fulfill these critical roles or commit themselves to acquiring them.
View Article and Find Full Text PDFApoptosis of granulocytes and the subsequent clearance of apoptotic cells are important processes for the successful resolution of inflammation. Signalling pathways, including those involving NF-kappaB (nuclear factor kappaB), MAPK (mitogen-activated protein kinase) and PI3K (phosphoinositide 3-kinase) have been shown to be key regulators of inflammatory cell survival and apoptosis in vitro. In addition, manipulation of such pathways in vivo has indicated that they also play a role in the resolution of inflammation.
View Article and Find Full Text PDFThe inflammatory process, orchestrated against a variety of injurious stimuli, is composed of three inter-related phases; initiation, propagation and resolution. Understanding the interplay between these three phases and harnessing the beneficial properties of inflammation whilst preventing its damaging effects, will undoubtedly lead to the advent of much needed therapies, particularly in chronic disease states. The P2X7 receptor (P2X7R) is increasingly recognised as an important cell surface regulator of several key inflammatory molecules including IL-1beta, IL-18, TNF-alpha and IL-6.
View Article and Find Full Text PDFApoptosis is essential for clearance of potentially injurious inflammatory cells and subsequent efficient resolution of inflammation. Here we report that human neutrophils contain functionally active cyclin-dependent kinases (CDKs), and that structurally diverse CDK inhibitors induce caspase-dependent apoptosis and override powerful anti-apoptosis signals from survival factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF). We show that the CDK inhibitor R-roscovitine (Seliciclib or CYC202) markedly enhances resolution of established neutrophil-dependent inflammation in carrageenan-elicited acute pleurisy, bleomycin-induced lung injury, and passively induced arthritis in mice.
View Article and Find Full Text PDFInflammatory cell recruitment, activation, and apoptosis are highly regulated processes involving several checkpoints controlling the resolution of inflammation. We investigated the role of the mitogen-activated protein kinase (MAPK) signaling pathway (ie, ERK1/2) and apoptosis-regulating Bcl-2 family members (ie, Bcl-x(L) and Bax) in the resolution of a rat carrageenan-induced pleurisy model. The specific ERK1/2 inhibitor PD98059 enhanced the resolution of inflammation, whereas the MEK1/2 inhibitor U0126 had no effect and the flavonoid apigenin, a nonspecific inhibitor of ERK1/2 and COX-2, augmented inflammation.
View Article and Find Full Text PDFRationale: The role played by resident pleural macrophages in the initiation of pleural inflammation is currently unclear.
Objective: To evaluate the role of resident pleural macrophages in the initiation of inflammation.
Methods: We have used a conditional macrophage ablation strategy to determine the role of resident pleural macrophages in the regulation of neutrophil recruitment in a murine model of experimental pleurisy induced by the administration of carrageenan and formalin- fixed Staphylococcus aureus.
Articular cartilage injury presents a unique therapeutic challenge. As cartilage possesses no blood or nerve supply of its own it has a particular susceptibility to early injury and a poor capacity for self-repair. Treatment options are limited and injury can eventually lead to osteoarthritis.
View Article and Find Full Text PDFFailure of acute inflammation to resolve leads to persistence of the inflammatory response and may contribute to the development of chronic inflammation. Thus, an understanding of inflammatory resolution will provide insight into the etiology of chronic inflammation. In an acute pleurisy, polymorphonuclear leukocytes (PMNs) were found to predominate at the onset of the lesion but decreased in number by undergoing apoptosis, the principal mechanism by which PMNs died in this model.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
December 2003
One immunological component of asthma is believed to be the interaction of eosinophils with parasympathetic cholinergic nerves and a consequent inhibition of acetylcholine muscarinic M2 receptor activity, leading to enhanced acetylcholine release and bronchoconstriction. Here we have used an in vitro model of cholinergic nerve function, the human IMR32 cell line, to study this interaction. IMR32 cells, differentiated in culture for 7 days, expressed M2 receptors.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
June 2002
In vivo, eosinophils localize to airway cholinergic nerves in antigen-challenged animals, and inhibition of this localization prevents antigen-induced hyperreactivity. In this study, the mechanism of eosinophil localization to nerves was investigated by examining adhesion molecule expression by cholinergic nerves. Immunohistochemical and functional studies demonstrated that primary cultures of parasympathetic nerves express vascular cell adhesion molecule-1 (VCAM-1) and after cytokine pretreatment with tumor necrosis factor-alpha and interferon-gamma intercellular adhesion molecule-1 (ICAM-1).
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
June 2002
Eosinophils adhere to airway cholinergic nerves and influence nerve cell function by releasing granule proteins onto inhibitory neuronal M(2) muscarinic receptors. This study investigated the mechanism of eosinophil degranulation by cholinergic nerves. Eosinophils were cocultured with IMR32 cholinergic nerve cells, and eosinophil peroxidase (EPO) or leukotriene C(4) (LTC(4)) release was measured.
View Article and Find Full Text PDFThis article examines family processes in 17 families with multiple problems through a Bowenian perspective. It was hypothesized that the parents in these families would demonstrate lower levels of differentiation than a norm group of adults drawn from the general population. It was also predicted that these families with multiple problems would manifest distinct patterns of multigenerational problems.
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