This study examines the relationships of measures of occupational and academic self-efficacy; vocational interests; outcome expectations; academic ability; and perceived stress, support, and coping to the academic achievement of women and men enrolled in university-level engineering/ science programs. Students from diverse racial/ethnic backgrounds (N =. 197) responded to scales measuring the variables of interest; high school and college academic data were obtained from university records. Self-efficacy for academic milestones, in combination with other academic and support variables, was found to be the strongest predictor of college academic achievement. Outcome expectations, vocational interests, and low levels of stress were in turn the strongest predictors of academic self-efficacy. Prediction equations for Euro-American and Mexican-American students revealed no significant contribution of ethnicity to the prediction of college academic achievement; however, ethnicity did enter into the equations predicting the 2 selfefficacy variables.

The authors examine the current status of multicultural training in counselor education. Leading multicultural training programs are identified and described, and specific guidelines for improving multicultural training are provided.

Most drugs currently used for human therapy interact with proteins, altering their activity to modulate the pathological cell physiology. In contrast, 2-hydroxy-9-cis-octadecenoic acid (Minerval) was designed to modify the lipid organization of the membrane. Its structure was deduced following the guidelines of the mechanism of action previously proposed by us for certain antitumor drugs. The antiproliferative activity of Minerval supports the above-mentioned hypothesis. This molecule augments the propensity of membrane lipids to organize into nonlamellar (hexagonal H II ) phases, promoting the subsequent recruitment of protein kinase C (PKC) to the cell membrane. The binding of the enzyme to membranes was marked and significantly elevated by Minerval in model (liposomes) and cell (A549) membranes and in heart membranes from animals treated with this drug. In addition, Minerval induced increased PKC␣ expression (mRNA and protein levels) in A549 cells. This drug also induced PKC activation, which led to a p53-independent increase in p21 CIP expression, followed by a decrease in the cellular concentrations of cyclins A, B, and D3 and cdk2. These molecular changes impaired the cell cycle progression of A549 cells. At the cellular and physiological level, administration of Minerval inhibited the growth of cancer cells and exerted antitumor effects in animal models of cancer without apparent histological toxicity. The present results support the potential use of Minerval and related compounds in the treatment of tumor pathologies.

G protein-coupled receptors (GPCRs) 1 constitute the main class of membrane receptors and form the widest gene family known in the mammalian genome. Therefore, signal transduction via G proteins represents one of the most important ways of cell signaling (for a review, see Ref. 1). Upon activation by agonists, GPCRs undergo conformational changes that induce the activation of heterotrimeric G proteins, promoting the exchange of the GDP bound to the G␣ subunit for GTP. This exchange provokes the dissociation of the G␣ subunit from the G␤␥ dimer and enables both molecular entities to modulate the activity of specific effectors or other signaling proteins (e.g. G protein receptor kinases).The association of both GPCRs and G proteins to the plasma membrane makes them susceptible to their lipid environment so that lipid-protein interactions are crucial to their function. In recent years, evidence has accumulated showing that the plasma membrane organization is more complex than a simple "chaotic sea" of bipolar lipid molecules in a liquid-crystalline state that only serves to support membrane proteins (2). In fact, differentiated membrane domains with specific protein and lipid compositions can exist in a cell such as the basal and apical membranes of epithelial/endothelial cells, the pre-and postsynaptic membranes of neuronal synapses, or lipid rafts and caveolae. Moreover, the extracellular and cytosolic leaflets of the plasma membrane differ in their lipid composition (3), further demonstrating the relevance of lipids in the organization and function of the membrane. Natural membranes are composed of different amphitropic molecules that differ in their propensity to form secondary lipid structures that influence the structural properties of the membrane (for a review, see Ref. 4). In this context, hexagonal (H II ) structures regulate the localization and activity of some key membrane signaling proteins (5, 6). Indeed, we have recently been able to show that changes in the lipid composition of erythrocyte cell membranes can influence the membrane association of G proteins and protein kinase C in vivo (7). Moreover, the neural membranes of cold-adapted fishes contain higher levels of phosphatidylethanolamine (PE) species in winter than in summer (8). These lipid changes probably lower the solidto-liquid and lamellar-to-hexagonal phase transition temperatures of membranes to maintain protein function and cell signaling in neurons and other cells. These data suggest that hexagonal phase propensity plays a major role in regulating physiological processes and might also participate in the control of other pivotal cellular events influenced by membrane proteins, such as cell growth or energy metabolism.Our main goal was to elucidate the role of the membrane lipid structure in the association to membranes of heterotrimeric G proteins and the molecular entities formed after their receptor-mediated activation. For this purpose we used synthetic membranes (liposomes) and purified G proteins as model systems because their li...

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