Showing papers by "Vanderbilt University published in 1997"

Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL): Initial Reliability and Validity Data

Abstract: Objective To describe the psychometric properties of the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL) interview, which surveys additional disorders not assessed in prior K-SADS, contains improved probes and anchor points, includes diagnosis-specific impairment ratings, generates DSM-III-R and DSM-IV diagnoses, and divides symptoms surveyed into a screening interview and five diagnostic supplements. Method Subjects were 55 psychiatric outpatients and 11 normal controls (aged 7 through 17 years). Both parents and children were used as informants. Concurrent validity of the screen criteria and the K-SADS-PL diagnoses was assessed against standard self-report scales. Interrater ( n = 15) and test-retest ( n = 20) reliability data were also collected (mean retest interval: 18 days; range: 2 to 38 days). Results Rating scale data support the concurrent validity of screens and K-SADS-PL diagnoses. Interrater agreement in scoring screens and diagnoses was high (range: 93% to 100%). Test-retest reliability κ coefficients were in the excellent range for present and/or lifetime diagnoses of major depression, any bipolar, generalized anxiety, conduct, and oppositional defiant disorder (.77 to 1.00) and in the good range for present diagnoses of posttraumatic stress disorder and attention-deficit hyperactivity disorder (.63 to .67). Conclusion Results suggest the K-SADS-PL generates reliable and valid child psychiatric diagnoses. J. Am. Acad. Child Adolesc. Psychiatry , 1997, 36(7): 980–988.

Why Do Parents Become Involved in Their Children’s Education?

Abstract: This article reviews psychological theory and research critical to understanding why parents become involved in their children’s elementary and secondary education. Three major constructs are believed to be central to parents’ basic involvement decisions. First, parents’ role construction defines parents’ beliefs about what they are supposed to do in their children’s education and appears to establish the basic range of activities that parents construe as important, necessary, and permissible for their own actions with and on behalf of children. Second, parents’ sense of efficacy for helping their children succeed in school focuses on the extent to which parents believe that through their involvement they can exert positive influence on their children’s educational outcomes. Third, general invitations, demands, and opportunities for involvement refer to parents’ perceptions that the child and school want them to be involved. Hypotheses concerning the functioning of the three constructs in an additive mode...

Changing Views of the Role of Matrix Metalloproteinases in Metastasis

Abstract: Metastatic spread of cancer continues to be the greatest barrier to cancer cure. Understanding the molecular mechanisms of metastasis is crucial for the design and effective use of novel therapeutic strategies to combat metastases. One class of molecules that has been repeatedly implicated in metastasis is the matrix metalloproteinases (MMPs). In this review, we re-examine the evidence that MMPs are associated with metastasis and that they make a functional contribution to the process. Initially, it was believed that the major role of MMPs in metastasis was to facilitate the breakdown of physical barriers to metastasis, thus promoting invasion and entry into and out of blood or lymphatic vessels (intravasation, extravasation). However, recent evidence suggests that MMPs may have a more complex role in metastasis and that they may make important contributions at other steps in the metastatic process. Studies using intravital videomicroscopy, as well as experiments in which levels of MMPs or their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]) are manipulated genetically or pharmacologically, suggest that MMPs are key regulators of growth of tumors, at both primary and metastatic sites. On the basis of this evidence, a new view of the functional role of MMPs in metastasis is presented, which suggests that MMPs are important in creating and maintaining an environment that supports the initiation and maintenance of growth of primary and metastatic tumors. Further clarification of the mechanisms by which MMPs regulate growth of primary and metastatic tumors will be important in the development of novel therapeutic strategies against metastases.

A Nongray Theory of Extrasolar Giant Planets and Brown Dwarfs

Abstract: We present the results of a new series of nongray calculations of the atmospheres, spectra, colors, and evolution of extrasolar giant planets (EGPs) and brown dwarfs for effective temperatures below 1300 K This theory encompasses most of the mass/age parameter space occupied by substellar objects and is the first spectral study down to 100 K These calculations are in aid of the multitude of searches being conducted or planned around the world for giant planets and brown dwarfs and reveal the exotic nature of the class Generically, absorption by H2 at longer wavelengths and H2O opacity windows at shorter wavelengths conspire to redistribute flux blueward Below 1200 K, methane is the dominant carbon bearing molecule and is a universal diagnostic feature of EGP and brown dwarf spectra We find that the primary bands in which to search are Z (~105 ?m), J (~12 ?m), H (~16 ?m), K (~22 ?m), M (~5 ?m), and N (~10 ?m), that enhancements of the emergent flux over blackbody values, in particular in the near infrared, can be by many orders of magnitude, and that the infrared colors of EGPs and brown dwarfs are much bluer than previously believed In particular, relative to J and H, the K band flux is reduced by CH4 and H2 absorption Furthermore, we conclude that for Teff's below 1200 K most or all true metals may be sequestered below the photosphere, that an interior radiative zone is a generic feature of substellar objects, and that clouds of H2O and NH3 are formed for Teff's below ~400 and ~200 K, respectively This study is done for solar-metallicity objects in isolation and does not include the effects of stellar insulation Nevertheless, it is a comprehensive attempt to bridge the gap between the planetary and stellar realms and to develop a nongray theory of objects from 03MJ (Saturn) to 70MJ (~007 M?) We find that the detection ranges for brown dwarf/EGP discovery of both ground- and space-based telescopes are larger than previously estimated

Customer Satisfaction, Productivity, and Profitability: Differences Between Goods and Services

Abstract: There is widespread belief that firms should pursue superiority in both customer satisfaction and productivity. However, there is reason to believe these two goals are not always compatible. If a firm improves productivity by “downsizing,” it may achieve an increase in productivity in the short-term, but future profitability may be threatened if customer satisfaction is highly dependent on the efforts of personnel. If so, there are potential tradeoffs between customer satisfaction and productivity for industries as diverse as airlines, banking, education, hotels, and restaurants. Managers in these types of service industries, as well as goods industries in which the service component is increasing, need to understand whether or not this is the case. For example, if efforts to improve productivity can actually harm customer satisfaction---and vice-versa---the downsizing of U.S. and European companies should be viewed with concern. It follows that developing a better understanding of how customer satisfaction and productivity relate to one another is of substantial and growing importance, especially in light of expected continued growth in services throughout the world economy. The objective of this paper is to investigate whether there are conditions under which there are tradeoffs between customer satisfaction and productivity. A review of the literature reveals two conflicting viewpoints. One school of thought argues that customer satisfaction and productivity are compatible, as improvements in customer satisfaction can decrease the time andeffort devoted to handling returns, rework, warranties, and complaint management, while at the same time lowering the cost of making future transactions. The second argues that increasing customer satisfaction should increase costs, as doing so often requires efforts to improve product attributes or overall product design. A conceptual framework useful in resolving these contradictory viewpoints is developed. The framework serves, in turn, as a basis for developing a theoretical model relating customer satisfaction and productivity. The model predicts that customer satisfaction and productivity are less likely to be compatible when: 1 customer satisfaction is relatively more dependent on customization---the degree to which the firm's offering is customized to meet heterogeneous customers' needs---as opposed to standardization---the degree to which the firm's offering is reliable, standardized, and free from deficiencies; and 2 when it is difficult costly to provide high levels of both customization and standardization simultaneously. To move forward from the model's propositions to the development of testable hypotheses, we argue that services are more likely than goods to have the preceding characteristics. Hence, tradeoffs between customer satisfaction and productivity should be more prevalent for services than for goods. Although this classification is not precise---many services are standardizable and many goods have a service component---it has the advantage of allowing an initial test of the propositions. The empirical work employs a database matching customer-based measures of firm performance with traditional measures of business performance, such as productivity and Return on Investment ROI. The central feature of this database is the set of customer satisfaction indices provided by the Swedish Customer Satisfaction Barometer SCSB. The SCSB provides a uniform set of comparable customer-based firm performance measures and offers a unique opportunity to test the study's hypotheses. The findings indicate that the association between changes in customer satisfaction and changes in productivity is positive for goods, but negative for services. In addition, while both customer satisfaction and productivity are positively associated with ROI for goods and services, the interaction between the two is positive for goods but significantly less so for services. Taken together, the findings suggest support for the contention that tradeoffs are more likely for services. Hence, simultaneous attempts to increase both customer satisfaction and productivity are likely to be more challenging in such industries. Of course, this does not imply that such firms should not seek improvements in both productivity and customer satisfaction. For example, appropriate applications of information technology may improve both customer satisfaction and productivity simultaneously. The findings should provide motivation for future research concerning the nature of customer satisfaction and productivity, as well as appropriate strategy and tactics for each one. It is worth emphasizing that this is an issue that is not only important today, but certainly will become even more important in the future. As the growth of services continues and world markets become increasingly competitive, the importance of customer satisfaction will also increase. To compete in such a world, firms must strike the right balance between their efforts to compete efficiently and their efforts to compete effectively.

Perioperative Maintenance of Normothermia Reduces the Incidence of Morbid Cardiac Events: A Randomized Clinical Trial

Abstract: Objective. —To assess the relationship between body temperature and cardiac morbidity during the perioperative period. Design. —Randomized controlled trial comparing routine thermal care (hypothermic group) to additional supplemental warming care (normothermic group). Setting. —Operating rooms and surgical intensive care unit at an academic medical center. Subjects. —Three hundred patients undergoing abdominal, thoracic, or vascular surgical procedures who either had documented coronary artery disease or were at high risk for coronary disease. Outcome Measure. —The relative risk of a morbid cardiac event (unstable angina/ischemia, cardiac arrest, or myocardial infarction) according to thermal treatment. Cardiac outcomes were assessed in a double-blind fashion. Results. —Mean core temperature after surgery was lower in the hypothermic group (35.4±0.1°C) than in the normothermic group (36.7±0.1°C) ( P P =.02). Hypothermia was an independent predictor of morbid cardiac events by multivariate analysis (relative risk, 2.2; 95% confidence interval, 1.1-4.7; P =.04), indicating a 55% reduction in risk when normothermia was maintained. Postoperative ventricular tachycardia also occurred less frequently in the normothermic group than in the hypothermic group (2.4% vs 7.9%; P =.04). Conclusion. —In patients with cardiac risk factors who are undergoing noncardiac surgery, the perioperative maintenance of normothermia is associated with a reduced incidence of morbid cardiac events and ventricular tachycardia.

The Components of the Bid-Ask Spread: A General Approach

Abstract: A simple time-series market microstructure model is constructed within which existing models of spread components are reconciled We show that existing models fail to decompose the spread into all its components Two alternative extensions of the simple model are developed to identify all the components of the spread and to estimate the spread at which trades occur The empirical results support the presence of a large order processing component and smaller, albeit significant, adverse selection and inventory components The spread components differ significantly according to trade size and are also sensitive to assumptions about the relation between orders and trades

A theoretical framework for intraguild predation

Abstract: Many important issues in community ecology revolve around the interplay of competition and predation Species that compete may also be locked in predator-prey interactions, a mixture of competition and predation known as "intraguild predation" (IGP) There is growing evidence for the importance of IGP in many natural communities, yet little formal ecological theory addresses this particular blend of interactions In this article, we explore the consequences of incorporating IGP into standard models of exploitative competition and food chains (a general resource-consumer model, a Lotka-Volterra food chain model, and Schoener's exploitative competition model) Our theoretical analyses suggest a general criterion for coexistence in IGP systems: the intermediate species (the prey in intraguild predation) should be superior at exploitative competition for the shared resource, whereas the top species (the predator) should gain significantly from its consumption of the intermediate species Along gradients in en

Regulation of serotonin-2C receptor G-protein coupling by RNA editing

Abstract: The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) elicits a wide array of physiological effects by binding to several receptor subtypes. The 5-HT2 family of receptors belongs to a large group of seven-transmembrane-spanning G-protein-coupled receptors and includes three receptor subtypes (5-HT2A, 5-HT(2B) and 5-HT(2C)) which are linked to phospholipase C, promoting the hydrolysis of membrane phospholipids and a subsequent increase in the intracellular levels of inositol phosphates and diacylglycerol. Here we show that transcripts encoding the 2C subtype of serotonin receptor (5-HT(2C)R) undergo RNA editing events in which genomically encoded adenosine residues are converted to inosines by the action of double-stranded RNA adenosine deaminase(s). Sequence analysis of complementary DNA isolates from dissected brain regions have indicated the tissue-specific expression of seven major 5-HT(2C) receptor isoforms encoded by eleven distinct RNA species. Editing of 5-HT(2C)R messenger RNAs alters the amino-acid coding potential of the predicted second intracellular loop of the receptor and can lead to a 10-15-fold reduction in the efficacy of the interaction between receptors and their G proteins. These observations indicate that RNA editing is a new mechanism for regulating serotonergic signal transduction and suggest that this post-transcriptional modification may be critical for modulating the different cellular functions that are mediated by other members of the G-protein-coupled receptor superfamily.

Reactive and proactive aggression in school children and psychiatrically impaired chronically assaultive youth

Abstract: The authors proposed that reactively aggressive and proactively aggressive types of antisocial youth would differ in developmental histories, concurrent adjustment, and social information-processing patterns. In Study 1, 585 boys and girls classified into groups called reactive aggressive, proactive aggressive, pervasively aggressive (combined type), and nonaggressive revealed distinct profiles. Only the reactive aggressive groups demonstrated histories of physical abuse and early onset of problems, adjustment problems in peer relations, and inadequate encoding and problem-solving processing patterns. Only the proactive aggressive groups demonstrated a processing pattern of anticipating positive outcomes for aggressing. In Study 2, 50 psychiatrically impaired chronically violent boys classified as reactively violent or proactively violent demonstrated differences in age of onset of problem behavior, adjustment problems, and processing problems.

Suppression of tumor necrosis factor-induced cell death by inhibitor of apoptosis c-IAP2 is under NF-κB control

Abstract: Members of the NF-κB/Rel and inhibitor of apoptosis (IAP) protein families have been implicated in signal transduction programs that prevent cell death elicited by the cytokine tumor necrosis factor α (TNF). Although NF-κB appears to stimulate the expression of specific protective genes, neither the identities of these genes nor the precise role of IAP proteins in this anti-apoptotic process are known. We demonstrate here that NF-κB is required for TNF-mediated induction of the gene encoding human c-IAP2. When overexpressed in mammalian cells, c-IAP2 activates NF-κB and suppresses TNF cytotoxicity. Both of these c-IAP2 activities are blocked in vivo by coexpressing a dominant form of IκB that is resistant to TNF-induced degradation. In contrast to wild-type c-IAP2, a mutant lacking the C-terminal RING domain inhibits NF-κB induction by TNF and enhances TNF killing. These findings suggest that c-IAP2 is critically involved in TNF signaling and exerts positive feedback control on NF-κB via an IκB targeting mechanism. Functional coupling of NF-κB and c-IAP2 during the TNF response may provide a signal amplification loop that promotes cell survival rather than death.

Comparison and Evaluation of Retrospective Intermodality Brain Image Registration Techniques

Abstract: Comparison and evaluation of retrospective intermodality brain image registration techniques

Commercial scenarios for the Web: opportunities and challenges

Abstract: The potential of the World Wide Web on the Internet as a commercial medium and market has been widely documented in a variety of media. However, a critical examination of its commercial development has received little attention. Therefore, in this paper we propose a structural framework for examining the explosion in commercial activity on the Web. First, we explore the role of the Web as a distribution channel and a medium for marketing communications. Second, we examine the factors that have led to the development of the Web as a commercial medium, evaluating the benefits it provides to both consumers and firms and its attractive size and demographic characteristics. Third, we discuss the barriers to commercial growth of the Web from both the supply and demand side perspectives. This analysis leads to a new classification of commercialization efforts that categorizes commercial Web sites into six distinct types including 1) Online Storefront, 2) Internet Presence, 3) Content, 4) Mall, 5) Incentive Site, and, 6) Search Agent. The first three comprise the “Integrated Destination Site,” and the latter three represent forms of “Web Traffic Control.” Our framework, argued in the context of integrated marketing, facilitates greater understanding of the Web as a commercial medium, and allows examination of commercial Web sites in terms of the opportunities and challenges firms face in the rush towards commercialization.

The Effects of Ibuprofen on the Physiology and Survival of Patients with Sepsis

Abstract: Background In patients with sepsis the production of arachidonic acid metabolites by cyclooxygenase increases, but the pathophysiologic role of these prostaglandins is unclear. In animal models, inhibition of cyclooxygenase by treatment with ibuprofen before the onset of sepsis reduces physiologic abnormalities and improves survival. In pilot studies of patients with sepsis, treatment with ibuprofen led to improvements in gas exchange and airway mechanics. Methods From October 1989 to March 1995, we conducted a randomized, double-blind, placebo-controlled trial of intravenous ibuprofen (10 mg per kilogram of body weight [maximal dose, 800 mg], given every six hours for eight doses) in 455 patients who had sepsis, defined as fever, tachycardia, tachypnea, and acute failure of at least one organ system. Results In the ibuprofen group, but not the placebo group, there were significant declines in urinary levels of prostacyclin and thromboxane, temperature, heart rate, oxygen consumption, and lactic acidosis....

Inhibition of human colon cancer cell growth by selective inhibition of cyclooxygenase-2.

Abstract: A considerable amount of evidence collected from several different experimental systems indicates that cyclooxygenase-2 (COX-2) may play a role in colorectal tumorigenesis. Large epidemiologic studies have shown a 40-50% reduction in mortality from colorectal cancer in persons taking aspirin or other nonsteroidal antiinflammatory drugs on a regular basis. One property shared by all of these drugs is their ability to inhibit COX, a key enzyme in the conversion of arachidonic acid to prostaglandins. Two isoforms of COX have been characterized, COX-1 and COX-2. COX-2 is expressed at high levels in intestinal tumors in humans and rodents. In this study, we selected two transformed human colon cancer cell lines for studies on the role of COX-2 in intestinal tumorigenesis. We evaluated HCA-7 cells which express high levels of COX-2 protein constitutively and HCT-116 cells which lack COX-2 protein. Treatment of nude mice implanted with HCA-7 cells with a selective COX-2 inhibitor (SC-58125), reduced tumor formation by 85-90%. SC-58125 also inhibited colony formation of cultured HCA-7 cells. Conversely, SC-58125 had no effect on HCT-116 implants in nude mice or colony formation in culture. Here we provide evidence that there may be a direct link between inhibition of intestinal cancer growth and selective inhibition of the COX-2 pathway.

Prospective study of blunt aortic injury: Multicenter trial of the American Association for the Surgery of Trauma

Abstract: Background: Blunt aortic injury is a major cause of death from blunt trauma. Evolution of diagnostic techniques and methods of operative repair have altered the management and posed new questions in recent years. Methods: This study was a prospectively conducted multicenter trial involving 50 trauma centers in North America under the direction of the Multi-institutional Trial Committee of the American Association for the Surgery of Trauma. Results: There were 274 blunt aortic injury cases studied over 2.5 years, of which 81% were caused by automobile crashes. Chest computed tomography and transesophageal echocardiography were applied in 88 and 30 cases, respectively, and were 75 and 80% diagnostic, respectively. Two hundred seven stable patients underwent planned thoracotomy and repair. Clamp and sew technique was used in 73 (35%) and bypass techniques in 134 (65%). Overall mortality was 31%, with 63% of deaths being attributable to aortic rupture; mortality was not affected by method of repair. Paraplegia occurred postoperatively in 8.7%. Logistic regression analysis demonstrated clamp and sew (p = 0.002) and aortic cross clamp time of 30 minutes (p = 0.01) to be associated with development of postoperative paraplegia. Conclusions: Rupture after hospital admission remains a major problem. Although newer diagnostic techniques are being applied, at this time aortography remains the diagnostic standard. Aortic cross clamp time beyond 30 minutes was associated with paraplegia; bypass techniques, which provide distal aortic perfusion, produced significantly lower paraplegia rates than the clamp and sew approach.

Bone morphogenetic proteins (BMPs) as regulators of dorsal forebrain development

Abstract: Bone Morphogenetic Proteins (BMPs) play crucial roles in a variety of developmental processes, but their functions during early vertebrate brain development are largely unknown. To investigate this problem, we have compared by in situ hybridization the expression of five Bmp genes belonging to the Drosophila Decapentaplegic (Bmp2 and Bmp4) and 60A subgroups (Bmp5, Bmp6 and Bmp7). Striking co-expression of these Bmps is observed within the dorsomedial telencephalon, coincident with a future site of choroid plexus development. Bmp co-expression overlaps that of Msx1 and Hfh4, and is complementary to that of Bf1. The domain of Bmp co-expression is also associated with limited growth of the neuroectoderm, as revealed by morphological observation, reduced cell proliferation, and increased local programmed cell death. In vitro experiments using explants from the embryonic lateral telencephalic neuroectoderm reveal that exogenous BMP proteins (BMP4 and BMP2) induce expression of Msx1 and inhibit Bf1 expression, a finding consistent with their specific expression patterns in vivo. Moreover, BMP proteins locally inhibit cell proliferation and increase apoptosis in the explants. These results provide evidence that BMPs function during regional morphogenesis of the dorsal telencephalon by regulating specific gene expression, cell proliferation and local cell death.

Supportive parenting, Ecological Context, and Children's Adjustment: A seven-Year Longitudianl Study

Abstract: Two major questions regarding the possible impact of early supportive parenting (SP) on children's school adjustment were addressed:(1) Does SP assessed prekindergarten predict grade 6 adjustment after controlling for early barsh parenting (HP)? (2) Does SP moderate (buffer) the impact of early family adversity on grade 6 adjustment? Parenting and family adversity data were drawn from home-visit interviews with 585 mothers conducted prekindergarten. Four SP measure were derived: mother-to-child warmth, proactive teaching, inductive discipline, and positive involvement. HP was indexed as the use of harsh, physical disciple. Family adversity indicators were socioeconomic disadvantage, family stress, and single parenthood. Children 's adjustment (behavior problems, social skills, and academic performance) in kindergarten and grade 6 was assessedvia teacher ratings and school records. SP predicted adjustment in grade 6, even after controlling for kindergarten adjustment and HP. High levels of SP mitigated the effects of family adversity on later behavior problems. These findings implicate both direct (main effect)and indirect (moderator of adversity) processes in the linkage between positive and supportive aspects of parenting and children's school adjustment.

Peer-Assisted Learning Strategies: Making Classrooms More Responsive to Diversity:

Abstract: The primary focus of this study was to determine the effectiveness of a classwide peer tutoring program in reading for three learner types: low achievers with and without disabilities and average achievers. Twelve schools, stratified on student achievement and family income, were assigned randomly to experimental and control groups. Twenty teachers implemented the peer tutoring program for 15 weeks; 20 did not implement it. In each of the 40 classrooms, data were collected systematically on three students representing the three learner types. Pre- and posttreatment reading achievement data were collected on three measures of the Comprehensive Reading Assessment Battery. Findings indicated that, irrespective of type of measure and type of learner, students in peer tutoring classrooms demonstrated greater reading progress. Implications for policymaking are discussed.

Modeling piezoelectric stack actuators for control of micromanipulation

Abstract: A nonlinear lumped-parameter model of a piezoelectric stack actuator has been developed to describe actuator behavior for purposes of control system analysis and design, and, in particular, for microrobotic applications requiring accurate position and/or force control. In formulating this model, the authors propose a generalized Maxwell resistive capacitor as a lumped-parameter causal representation of rate-independent hysteresis. Model formulation is validated by comparing results of numerical simulations to experimental data. Validation is followed by a discussion of model implications for purposes of actuator control.

A new marketing paradigm for electronic commerce

Abstract: The World Wide Web possesses unique characteristics that distinguish it in important ways from traditional commercial communications environments. Because the Web presents a fundamentally different environment for marketing activities than traditional media, conventional marketing activities are becoming transformed, as they are often difficult to implement in their present form. In this article, we discuss the idea that these changes portend an evolution in the ''marketing concept'' and argue that in order for marketing efforts to be successful in this new medium, a new business paradigm is required. In this new approach, the marketing function must be reconstructed to facilitate electronic commerce in the emerging electronic society underlying the Web.

Composition, process, and performance in self-managed groups: The role of personality.

Abstract: Using the five factor model with an emphasis on extraversion and conscientiousness, the authors investigated how personality is related to small group processes and outcomes. Graduate students (N = 289) assigned to 4- and 5-person teams in 61 groups engaged in a series of creative problem-solving tasks over a period of several weeks. Extraversion was associated with group processes and outcomes at both individual and group levels of analysis. At the individual level, extraverts were perceived by others as having greater effect than introverts on group outcomes. Covariance structure modeling suggested that extraverts induce these perceptions through the provision of both socioemotional and task-related inputs. At the group level, the proportion of relatively extraverted members was related curvilinearly to task focus and group performance. Contrary to expectations, Conscientiousness was unrelated to processes and outcomes at either the individual or group level.

Involvement of Sonic hedgehog (Shh) in mouse embryonic lung growth and morphogenesis

Abstract: Branching morphogenesis of the embryonic lung requires interactions between the epithelium and the mesenchyme. Previously, we reported that Sonic hedgehog (Shh) transcripts are present in the epithelium of the developing mouse lung, with highest levels in the terminal buds. Here, we report that transcripts of mouse patched (Ptc), the homologue of a Drosophila gene encoding a putative transmembrane protein required for hedgehog signaling, are expressed at high levels in the mesenchyme adjacent to the end buds. To investigate the function of SHH in lung development, Shh was overexpressed throughout the distal epithelium, using the surfactant protein-C (SP-C)-enhancer/promoter. Beginning around 16.5 dpc, when Shh and Ptc RNA levels are normally both declining, this treatment caused an increase in the ratio of interstitial mesenchyme to epithelial tubules in transgenic compared to normal lungs. Transgenic newborn mice die soon after birth. Histological analysis of the lungs at the light and electron microscope level shows an abundance of mesenchyme and the absence of typical alveoli. In vivo BrdU labeling indicates that Shh overexpression results in increased mesenchymal and epithelial cell proliferation at 16.5 and 17.5 dpc. However, analysis of CC-10 and SP-C expression reveals no significant inhibition in the differentiation of proximal and distal epithelial cells. The expression of genes potentially regulated by SHH was also examined. No difference could be observed between transgenic and control lungs in either the level or distribution of Bmp4, Wnt2 and Fgf7 RNA. By contrast, Ptc is clearly upregulated in the transgenic lung. These results thus establish a role for SHH in lung morphogenesis, and suggest that SHH normally regulates lung mesenchymal cell proliferation in vivo.