Theoretical investigations of intercellular communication in the microcirculation: Conducted responses, myoendothelial projections and endothelium derived hyperpolarizing factor

The contractile state of microcirculatory vessels is a major determinant of the blood pressure of the whole systemic circulation. Continuous bi-directional communication exists between the endothelial cells (ECs) and smooth muscle cells (SMCs) that regulates calcium (Ca2+) dynamics in these cells. This study presents theoretical approaches to understand some of the important and currently unresolved microcirculatory phenomena. ^ Agonist induced events at local sites have been shown to spread long distances in the microcirculation. We have developed a multicellular computational model by integrating detailed single EC and SMC models with gap junction and nitric oxide (NO) coupling to understand the mechanisms behind this effect. Simulations suggest that spreading vasodilation mainly occurs through Ca 2+ independent passive conduction of hyperpolarization in RMAs. Model predicts a superior role for intercellular diffusion of inositol (1,4,5)-trisphosphate (IP3) than Ca2+ in modulating the spreading response. ^ Endothelial derived signals are initiated even during vasoconstriction of stimulated SMCs by the movement of Ca2+ and/or IP3 into the EC which provide hyperpolarizing feedback to SMCs to counter the ongoing constriction. Myoendothelial projections (MPs) present in the ECs have been recently proposed to play a role in myoendothelial feedback. We have developed two models using compartmental and 2D finite element methods to examine the role of these MPs by adding a sub compartment in the EC to simulate MP with localization of intermediate conductance calcium activated potassium channels (IKCa) and IP3 receptors (IP 3R). Both models predicted IP3 mediated high Ca2+ gradients in the MP after SMC stimulation with limited global spread. This Ca 2+ transient generated a hyperpolarizing feedback of ∼ 2–3mV. ^ Endothelium derived hyperpolarizing factor (EDHF) is the dominant form of endothelial control of SMC constriction in the microcirculation. A number of factors have been proposed for the role of EDHF but no single pathway is agreed upon. We have examined the potential of myoendothelial gap junctions (MEGJs) and potassium (K+) accumulation as EDHF using two models (compartmental and 2D finite element). An extra compartment is added in SMC to simulate micro domains (MD) which have NaKα2 isoform sodium potassium pumps. Simulations predict that MEGJ coupling is much stronger in producing EDHF than alone K+ accumulation. On the contrary, K+ accumulation can alter other important parameters (EC V m, IKCa current) and inhibit its own release as well as EDHF conduction via MEGJs. The models developed in this study are essential building blocks for future models and provide important insights to the current understanding of myoendothelial feedback and EDHF.^

Spirituality and transformational leadership in education

The purpose of this study was to investigate the relationship between school principals' self-reported spirituality and their transformational leadership behaviors. The relationship between spirituality and transactional leadership behaviors was also explored. The study used Bass and Avolio's (1984) Full Range Leadership Model as the theoretical framework conceptualizing transformational leadership. Data were collected using online surveys. Overall, six principals and sixty-nine teachers participated in the study. Principal surveys contained three parts: the Multifactor Leadership Questionnaire (MLQ Form-5X Short), the modified Spirituality Well-Being Scale (SWBS) and demographic information. Teacher surveys included two parts: the MLQ-5X and demographic information. The MLQ-5X was used to identify the degree of principals' transformational and transactional leadership behaviors. The modified SWBS (Existential Well Being) was used to determine principals' degree of spirituality. The correlation coefficients for the transformational leadership styles of inspirational motivation and idealized behavioral influence were significantly related to principals' spirituality. In addition, a multiple regression analysis including the five measures of transformational leadership as predictors suggested that spirituality is positively related to an individual's transformational leadership behaviors. A multiple regression analysis utilizing a linear combination of all transformational leadership and transactional measures was predictive of spirituality. Finally, it appears that the inspirational motivation measure of transformational leadership accounts for a significant amount of unique variance independent of the other seven transformational and transactional leadership measures in predicting spirituality. Based on the findings from this study, the researcher proposed a modification of Bass and Avolio's (1985) Full Range Leadership Model. An additional dimension, spirituality, was added to the continuum of leadership styles. The findings from this study imply that principals' self-reported levels of spirituality was related to their being perceived as displaying transformational leadership behaviors. Principals who identified themselves as "spiritual", were more likely to be characterized by the transformational leadership style of inspirational motivation.

Multicultural Literacy in Education: Meeting the Objectives of the Florida Sunshine State Standards

The purpose of this paper is to show how incorporating multicultural literacy in education can meet the Florida Sunshine State Standards to promote a more equitable approach to classroom discourse and a qualitative teacher-facilitated learning environment for students who reflect a multicultural and global community.

Diversity in Education: Profiles of Students at FIU's School of Hospitality Management

The authors are conducting a study of career patterns for students enrolled in the Florida International University School of Hospitality Management. A preliminary ethnographic phase of the study was to profile a variety of student participants in order to identify potential factors which might affect career patterns. The result is a fascinating and diverse mosaic of ambitious young people and a wealth of insight for corporate recruiting.