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Eosinophils play a primary role in the pathophysiology of asthma. In the lung, the activation state of the infiltrating eosinophils determines the extent of tissue damage. Interleukin-5 (IL-5) and leukotriene B4 (LTB4) are important signaling molecules involved in eosinophil recruitment and activation. However, the physiological processes that regulate these activation events are largely unknown. In this study we have examined the mechanisms of human eosinophil NADPH oxidase regulation by IL-5, LTB4, and phorbol ester (PMA). These stimuli activate a Zn2+-sensitive plasma membrane proton channel, and treatment of eosinophils with Zn2+ blocks superoxide production. We have demonstrated that eosinophil intracellular pH is not altered by IL-5 activation of NADPH oxidase. Additionally, PKCdelta inhibitors block PMA, IL-5 and LTB4 mediated superoxide formation. Interestingly, the PKCdelta-selective inhibitor, rottlerin, does not block proton channel activation by PMA indicating that the oxidase and the proton conductance are regulated at distinct phosphorylation sites. IL-5 and LTB4, but not PMA, stimulated superoxide production is also blocked by inhibitors of PI 3-kinase indicating that activation of this enzyme is an upstream event common to both receptor signaling pathways. Our results indicate that the G-protein-coupled LTB4 receptor and the IL-5 cytokine receptor converge on a common signaling pathway involving PI 3-kinase and PKCdelta to regulate NADPH oxidase activity in human eosinophils.

(+44.4±1.4 mV) increased depolarization compared with PMA alone. Additionally, the protein kinase C (PKC) δ-selective blocker, rottlerin, inhibited PMA-stimulated depolarization, indicating that PKCδ was involved in regulating depolarization associated with eosinophil NADPH oxidase activity. Thus, the membrane depolarization that is associated with NADPH oxidase activation in eosinophils is sufficient to produce marked proton channel activation under physiological conditions.

We describe the development and validation of a new instrument, the Classroom Discourse Observation Protocol (CDOP), which quantifies teacher discourse moves (TDMs) from observational data in undergraduate STEM classrooms. TDMs can be conceptualized as epistemic tools that can mediate classroom discussions. Through an inductive–deductive coding process, we identified commonly occurring TDMs among a group of biology instructors ( n = 13, 37 class session) teaching in Active Learning Environments. We describe the CDOP coding scheme and its associated matrix that allows observers to reliably characterize TDMs in 2-min time intervals over the course of a class period. We present the protocol, discuss how it differs from existing classroom observation protocols, and describe the process by which it was developed and validated. Also, we show how this protocol is able to discriminate the discursive practices of instructors teaching in undergraduate STEM learning environments with sample qualitative and quantitative results that illustrate its utility for assessing and improving STEM instructional practices.

Reform efforts in undergraduate science, technology, engineering, and mathematics (STEM) instruction often emphasize student-centered teaching approaches, but relatively little attention is paid to the way STEM teachers use discourse when interacting with their students. In the present study, we examined the instructional and discourse behaviors of biology faculty members (N = 20) teaching in undergraduate biology classes. Although we found that the biology teachers spent most of their time guiding student learning in active learning activities and less time presenting, an analysis of their classroom communicative approaches showed that the participants mostly used authoritative and not dialogic discourse to teach biology content. Similarly, we found a strong positive correlation between biology teachers guiding student learning and authoritative, interactive approaches, suggesting that these teachers mostly asked the students to recall facts or basic concepts rather than asking them to collaboratively build knowledge. We describe the implications of these findings and our results for undergraduate biology instruction.

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Eosinophils and cytokines active on eosinophils, especially IL-5, are believed to be critically involved in chronic allergic diseases. IL-5 activates eosinophils and enhances their survival in vitro by delaying apoptosis. In this study, we found that lidocaine and six analogues blunt responses of eosinophils to IL-5. Lidocaine and its derivatives inhibit IL-5-mediated eosinophil survival in a concentration-dependent manner (IC50 = 110 μM for 30 pg/ml IL-5). At suboptimal lidocaine concentrations, the eosinophil survival response to IL-5 shifts and more IL-5 is required to maintain survival. The inhibitory effect requires at least 24-h exposure of eosinophils to lidocaine, and the protein kinase C activator, PMA, completely reverses the inhibition. A multiparameter flow-cytometric analysis shows that lidocaine hastens the apoptosis of eosinophils normally delayed by IL-5. Lidocaine does not affect IL-5R expression or IL-5-induced protein tyrosine phosphorylation. Lidocaine also inhibits eosinophil survival mediated by IL-3 or granulocyte-macrophage CSF, although less potently than that mediated by IL-5. Furthermore, lidocaine inhibits eosinophil superoxide production stimulated by IL-5, granulocyte-macrophage CSF, or IL-3, but not that stimulated by platelet-activating factor, immobilized IgG, or PMA. Lidocaine and its derivatives show novel immunomodulatory properties and are able to blunt eosinophil responses to cytokines in addition to their local anesthetic or antiarrhythmic properties. Thus, lidocaine and its derivatives may represent a new class of therapeutic agents to treat patients with allergic diseases.