Specific type IV pili groups in clinical isolates of Pseudomonas aeruginosa.

The relationships between specific type IV pili (TFP) groups and antibiotic resistance, biofilm formation, and bacterial motility were determined in 190 Pseudomonas aeruginosa clinical isolates. While motility and biofilm formation were determined by phenotypic assays, the presence of TFP was determined by PCR assay and antibiotic susceptibility by disk diffusion. The results showed a high ability to form biofilm (97.

Leukocyte compartments in the mouse lung: distinguishing between marginated, interstitial, and alveolar cells in response to injury.

We developed a flow cytometry-based assay to simultaneously quantify multiple leukocyte populations in the marginated vascular, interstitial, and alveolar compartments of the mouse lung. An intravenous injection of a fluorescently labeled anti-CD45 antibody was used to label circulating and marginated vascular leukocytes. Following vascular flushing to remove non-adherent cells and collection of broncho-alveolar lavage (BAL) fluid, lungs were digested and a second fluorescent anti-CD45 antibody was added ex vivo to identify cells not located in the vascular space.

Adenosine A2A receptor activation on CD4+ T lymphocytes and neutrophils attenuates lung ischemia-reperfusion injury.

Objective: Adenosine A(2A) receptor activation potently attenuates lung ischemia-reperfusion injury. This study tests the hypothesis that adenosine A(2A) receptor activation attenuates ischemia-reperfusion injury by inhibiting CD4+ T cell activation and subsequent neutrophil infiltration.

Methods: An in vivo model of lung ischemia-reperfusion injury was used.

Adenosine A2B receptors are highly expressed on murine type II alveolar epithelial cells.

The adenosine A(2B) receptor (A(2B)R) has a wide tissue distribution that includes fibroblasts and endothelial and epithelial cells. The recent generation of an A(2B)R(-/-) mouse constructed with a beta-galactosidase (beta-gal) reporter gene under control of the endogenous promoter has provided a valuable tool to quantify A(2B)R promoter activity (29). To determine the sites of expression of the A(2B) receptor in the mouse lung, histological and flow cytometric analysis of beta-gal reporter gene expression in various lung cell populations was performed.

NKT cells mediate pulmonary inflammation and dysfunction in murine sickle cell disease through production of IFN-gamma and CXCR3 chemokines.

Ischemia-reperfusion injury (IRI) triggers an inflammatory cascade that is initiated by the activation of CD1d-restricted iNKT cells. In sickle cell disease (SCD), misshapen erythrocytes evoke repeated transient bouts of microvascular IRI. Compared with C57BL/6 controls, NY1DD mice have more numerous and activated (CD69(+), interferon-gamma(+) [IFN-gamma(+)]) lung, liver, and spleen iNKT cells that are hyperresponsive to hypoxia/reoxygenation.

Are voltage-dependent ion channels involved in the endothelial cell control of vasomotor tone?

In the microcirculation, longitudinal conduction of vasomotor responses provides an essential means of coordinating flow distribution among vessels in a complex network. Spread of current along the vessel axis can display a regenerative component, which leads to propagation of vasomotor signals over many millimeters; the ionic basis for the regenerative response is unknown. We examined the responses to 10 s of focal electrical stimulation (30 Hz, 2 ms, 30 V) of mouse cremaster arterioles to test the hypothesis that voltage-dependent Na(+) (Na(v)) and Ca(2+) channels might be activated in long-distance signaling in microvessels.

Ca2+ and inositol 1,4,5-trisphosphate-mediated signaling across the myoendothelial junction.

Second messenger signaling between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) is poorly understood, but intracellular Ca2+ concentrations ([Ca2+]i) in the 2 cells are coordinated, possibly through gap junctions at the myoendothelial junction. To study heterocellular calcium signaling, we used a vascular cell coculture model composed of monolayers of ECs and VSMCs. Stimulation of either cell type leads to an increase in [Ca2+]i in the stimulated cell and a secondary increase in [Ca2+]i in the other cell type that was blocked by gap junction inhibitors.

Myocardial infarct-sparing effect of adenosine A2A receptor activation is due to its action on CD4+ T lymphocytes.

Background: We previously used adenosine A2A receptor (A2AR) knockout (KO) mice and bone marrow transplantation to show that the infarct-sparing effect of A2AR activation at reperfusion is primarily due to effects on bone marrow-derived cells. In this study we show that CD4+ but not CD8+ T lymphocytes contribute to myocardial ischemia/reperfusion injury.

Method And Results: After a 45-minute occlusion of the left anterior descending coronary artery and reperfusion, T cells accumulate in the infarct zone within 2 minutes.

Stimulation of A2A-adenosine receptors after myocardial infarction suppresses inflammatory activation and attenuates contractile dysfunction in the remote left ventricle.

Following myocardial infarction (MI), contractile dysfunction develops not only in the infarct zone but also in noninfarcted regions of the left ventricle remote from the infarct zone. Inflammatory activation secondary to MI stimulates inducible nitric oxide synthase (iNOS) induction with excess production of nitric oxide. We hypothesized that the anti-inflammatory effects of selective A(2A)-adenosine receptor (A(2A)AR) stimulation would suppress inflammation and preserve cardiac function in the remote zone early after MI.

Activated platelets contribute importantly to myocardial reperfusion injury.

Platelets become activated during myocardial infarction (MI), but the direct contribution of activated platelets to myocardial reperfusion injury in vivo has yet to be reported. We tested the hypothesis that activated platelets contribute importantly to reperfusion injury during MI in mice. After 30 min of ischemia and 60 min of reperfusion, P-selectin knockout mice had a significantly smaller infarct size than that of wild-type mice (P < 0.

Infarct-sparing effect of A2A-adenosine receptor activation is due primarily to its action on lymphocytes.

Background: A2A-adenosine receptor (A2AAR) activation on reperfusion after ischemia reduces the size of myocardial infarction, but the mechanism of action has not been fully defined.

Methods And Results: We created chimeric mice by bone marrow transplantation from A2AAR-knockout or green fluorescent donor mice to irradiated congenic C57BL/6 (B6) recipients. In the GFP chimeras, we were unable to detect green fluorescent-producing cells in the vascular endothelium, indicating that bone marrow-derived cells were not recruited to endothelium at appreciable levels after bone marrow transplantation and/or acute myocardial infarction.

A2A adenosine receptors on bone marrow-derived cells protect liver from ischemia-reperfusion injury.

Activation of the A2A adenosine receptor (A(2A)R) during reperfusion of various tissues has been found to markedly reduce ischemia-reperfusion injury. In this study, we used bone marrow transplantation (BMT) to create chimeric mice that either selectively lack or selectively express the A(2A)R on bone marrow-derived cells. Bolus i.