Showing papers by "University of North Carolina at Chapel Hill published in 1997"
TL;DR: Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents, and the results should assist health and social service providers, educators, and others in taking the first steps to diminish risk factors and enhance protective factors for young people.
Abstract: Context. —The main threats to adolescents' health are the risk behaviors they choose. How their social context shapes their behaviors is poorly understood. Objective. —To identify risk and protective factors at the family, school, and individual levels as they relate to 4 domains of adolescent health and morbidity: emotional health, violence, substance use, and sexuality. Design. —Cross-sectional analysis of interview data from the National Longitudinal Study of Adolescent Health. Participants. —A total of 12118 adolescents in grades 7 through 12 drawn from an initial national school survey of 90118 adolescents from 80 high schools plus their feeder middle schools. Setting. —The interview was completed in the subject's home. Main Outcome Measures. —Eight areas were assessed: emotional distress; suicidal thoughts and behaviors; violence; use of 3 substances (cigarettes, alcohol, marijuana); and 2 types of sexual behaviors (age of sexual debut and pregnancy history). Independent variables included measures of family context, school context, and individual characteristics. Results. —Parent-family connectedness and perceived school connectedness were protective against every health risk behavior measure except history of pregnancy. Conversely, ease of access to guns at home was associated with suicidality (grades 9-12: P P P P P P P P P P P P P P P Conclusions. —Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents. The results should assist health and social service providers, educators, and others in taking the first steps to diminish risk factors and enhance protective factors for our young people.
3,856 citations
Harvard University1, University of Alabama at Birmingham2, University of London3, University of Rochester4, University of Southern California5, University of North Carolina at Chapel Hill6, University of Cincinnati7, University of Minnesota8, National Institutes of Health9, Merck & Co.10, University of Miami11, Northwestern University12, Bristol-Myers Squibb13
TL;DR: In this article, the efficacy and safety of adding a protease inhibitor to two nucleoside analogues to treat human immunodeficiency virus type 1 (HIV-1) infection are not clear.
Abstract: Background The efficacy and safety of adding a protease inhibitor to two nucleoside analogues to treat human immunodeficiency virus type 1 (HIV-1) infection are not clear. We compared treatment with the protease inhibitor indinavir in addition to zidovudine and lamivudine with treatment with the two nucleosides alone in HIV-infected adults previously treated with zidovudine. Methods A total of 1156 patients not previously treated with lamivudine or protease inhibitors were stratified according to CD4 cell count (50 or fewer vs. 51 to 200 cells per cubic millimeter) and randomly assigned to one of two daily regimens: 600 mg of zidovudine and 300 mg of lamivudine, or that regimen with 2400 mg of indinavir. Stavudine could be substituted for zidovudine. The primary end point was the time to the development of the acquired immunodeficiency syndrome (AIDS) or death. Results The proportion of patients whose disease progressed to AIDS or death was lower with indinavir, zidovudine (or stavudine), and lamivudine (...
2,615 citations
TL;DR: Of the many factors examined that might affect the relation between breast cancer risk and use of HRT, only a woman's weight and body-mass index had a material effect: the increase in the relative risk of breast cancer diagnosed in women using HRT and associated with long durations of use in current and recent users was greater for women of lower than of higher weight or body- mass index.
2,343 citations
TL;DR: In this paper, the authors determined whether greater carotid artery intima-media thickness (IMT) in asymptomatic individuals is associated with increased risk of coronary heart disease (CHD).
Abstract: Few studies have determined whether greater carotid artery intima-media thickness (IMT) in asymptomatic individuals is associated prospectively with increased risk of coronary heart disease (CHD). In the Atherosclerosis Risk in Communities Study, carotid IMT, an index of generalized atherosclerosis, was defined as the mean of IMT measurements at six sites of the carotid arteries using B-mode ultrasound. The authors assessed its relation to CHD incidence over 4-7 years of follow-up (1987-1993) in four US communities (Forsyth County, North Carolina; Jackson, Mississippi; Minneapolis, Minnesota; and Washington County, Maryland) from samples of 7,289 women and 5,552 men aged 45-64 years who were free of clinical CHD at baseline. There were 96 incident events for women and 194 for men. In sex-specific Cox proportional hazards models adjusted only for age, race, and center, the hazard rate ratio comparing extreme mean IMT (> or = 1 mm) to not extreme (< 1 mm) was 5.07 for women (95% confidence interval 3.08-8.36) and 1.85 for men (95% confidence interval 1.28-2.69). The relation was graded (monotonic), and models with cubic splines indicated significant nonlinearity. The strength of the association was reduced by including major CHD risk factors, but remained elevated at higher IMT. Up to 1 mm mean IMT, women had lower adjusted annual event rates than did men, but above 1 mm their event rate was closer to that of men. Thus, mean carotid IMT is a noninvasive predictor of future CHD incidence.
1,969 citations
TL;DR: The findings suggest that the OHIP-14 has good reliability, validity and precision and will be important to replicate these findings in other populations.
Abstract: Growing recognition that quality of life is an important outcome of dental care has created a need for a range of instruments to measure oral health-related quality of life. This study aimed to derive a subset of items from the Oral Health Impact Profile (OHIP-49)-a 49-item questionnaire that measures people's perceptions of the impact of oral conditions on their well-being. Secondary analysis was conducted using data from an epidemiologic study of 1217 people aged 60+ years in South Australia. Internal reliability analysis, factor analysis and regression analysis were undertaken to derive a subset (OHIP-14) questionnaire and its validity was evaluated by assessing associations with sociodemographic and clinical oral status variables. Internal reliability of the OHIP-14 was evaluated using Cronbach's coefficient alpha. Regression analysis yielded an optimal set of 14 questions. The OHIP-14 accounted for 94% of variance in the OHIP-49; had high reliability (alpha = 0.88); contained questions from each of the seven conceptual dimensions of the OHIP-49; and had a good distribution of prevalence for individual questions. OHIP-14 scores and OHIP-49 scores displayed the same pattern of variation among sociodemographic groups of older adults. In a multivariate analysis of dentate people, eight oral status and sociodemographic variables were associated (P < 0.05) with both the OHIP-49 and the OHIP-14. While it will be important to replicate these findings in other populations, the findings suggest that the OHIP-14 has good reliability, validity and precision.
1,926 citations
TL;DR: H-RasV12-induced transformation can lead to the production of ·O2− through one or more pathways involving a flavoprotein and Rac1, suggesting a possible mechanism for the effects of antioxidants against Ras-induced cellular transformation.
Abstract: NIH 3T3 fibroblasts stably transformed with a constitutively active isoform of p21(Ras), H-RasV12 (v-H-Ras or EJ-Ras), produced large amounts of the reactive oxygen species superoxide (.O2-). .O2- production was suppressed by the expression of dominant negative isoforms of Ras or Rac1, as well as by treatment with a farnesyltransferase inhibitor or with diphenylene iodonium, a flavoprotein inhibitor. The mitogenic activity of cells expressing H-RasV12 was inhibited by treatment with the chemical antioxidant N-acetyl-L-cysteine. Mitogen-activated protein kinase (MAPK) activity was decreased and c-Jun N-terminal kinase (JNK) was not activated in H-RasV12-transformed cells. Thus, H-RasV12-induced transformation can lead to the production of .O2- through one or more pathways involving a flavoprotein and Rac1. The implication of a reactive oxygen species, probably .O2-, as a mediator of Ras-induced cell cycle progression independent of MAPK and JNK suggests a possible mechanism for the effects of antioxidants against Ras-induced cellular transformation.
1,593 citations
TL;DR: Data suggest that girls seen in a sample of pediatric practices from across the United States are developing pubertal characteristics at younger ages than currently used norms, and practitioners may need to revise their criteria for referral of girls with precocious puberty.
Abstract: Objective. To determine the current prevalence and mean ages of onset of pubertal characteristics in young girls seen in pediatric practices in the United States. Methods. A cross-sectional study was conducted by 225 clinicians in pediatric practices belonging to Pediatric Research in Office Settings, a practice-based research network. After standardized training in the assessment of pubertal maturation, practitioners rated the level of sexual maturation on girls 3 through 12 years who were undergoing complete physical examinations. Results. Data were analyzed for 17 077 girls, of whom 9.6% were African-American and 90.4% white. At age 3, 3% of African-American girls and 1% of white girls showed breast and/or pubic hair development, with proportions increasing to 27.2% and 6.7%, respectively, at 7 years of age. At age 8, 48.3% of African-American girls and 14.7% of white girls had begun development. At every age for each characteristic, African-American girls were more advanced than white girls. The mean ages of onset of breast development for African-American and white girls were 8.87 years (SD, 1.93) and 9.96 years (SD, 1.82), respectively; and for pubic hair development, 8.78 years (SD, 2.00) and 10.51 years (SD, 1.67), respectively. Menses occurred at 12.16 years (SD, 1.21) in African-American girls and 12.88 years (SD, 1.20) of age in white girls. Conclusions. These data suggest that girls seen in a sample of pediatric practices from across the United States are developing pubertal characteristics at younger ages than currently used norms. Practitioners may need to revise their criteria for referral of girls with precocious puberty, with attention to racial differences.
1,556 citations
TL;DR: It is concluded that CBFA1 mutations cause Cleidocranial dysplasia and that heterozygous loss of function is sufficient to produce the disorder.
1,517 citations
TL;DR: In this article, the elastic properties of carbon nanotubes and nanoropes were investigated using an empirical force-constant model and it was shown that the tensile Young's modulus and the torsion shear modulus of tubes are comparable to that of the diamond, while the bulk modulus is smaller.
Abstract: Elastic properties of carbon nanotubes and nanoropes are investigated using an empirical force-constant model. For single and multiwall nanotubes the elastic moduli are shown to be insensitive to structural details such as the helicity, the radius, and the number of walls. The tensile Young's modulus and the torsion shear modulus of tubes are comparable to that of the diamond, while the bulk modulus is smaller. Nanoropes composed of single wall nanotubes have the ideal elastic properties of high tensile stiffness and light weight.
1,431 citations
TL;DR: It is shown that multiwalled carbon nanotubes can be bent repeatedly through large angles using the tip of an atomic force microscope, without undergoing catastrophic failure.
Abstract: The curling of a graphitic sheet to form carbon nanotubes produces a class of materials that seem to have extraordinary electrical and mechanical properties. In particular, the high elastic modulus of the graphite sheets means that the nanotubes might be stiffer and stronger than any other known material, with beneficial consequences for their application in composite bulk materials and as individual elements of nanometre-scale devices and sensors. The mechanical properties are predicted to be sensitive to details of their structure and to the presence of defects, which means that measurements on individual nanotubes are essential to establish these properties. Here we show that multiwalled carbon nanotubes can be bent repeatedly through large angles using the tip of an atomic force microscope, without undergoing catastrophic failure. We observe a range of responses to this high-strain deformation, which together suggest that nanotubes are remarkably flexible and resilient.
1,430 citations
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TL;DR: It is suggested that theoretical and conceptual models that use an organismic or systems metaphor for understanding families are important for stimulating new research and organizing existing data, and that advances in these theories over the past few decades have expanded the potential for understanding child development and adult adaptation.
Abstract: In this chapter, we discuss theoretical and conceptual models that use an organismic or systems metaphor for understanding families. We suggest that such theories are important for stimulating new research and organizing existing data, and that advances in these theories over the past few decades have expanded the potential for understanding child development, as well as adult adaptation and the development of close relationships. These paradigms follow from models that view development as resulting from the transactional regulatory processes of dynamic systems. Such models are helpful for considering multiple influences on development and adaptation and have implications for the design of effective interventions. We focus on the specifics of systems theories as applied to families, and the research generated by or consistent with these views. Our review is not exhaustive; rather, we intend to give a sense of the direction of this work and its importance for the understanding of development and adaptation.
TL;DR: A maternally expressed Drosophila TCF family member is cloned, dTCF, which mediates Wingless signaling as a bipartite transcription factor and binds a canonical TCF DNA motif and interacts with the beta-catenin homolog Armadillo.
TL;DR: N2 fixation by Trichodesmium is likely a major input to the marine and global nitrogen cycle.
Abstract: Planktonic marine cyanobacteria of the genus Trichodesmium occur throughout the oligotrophic tropical and subtropical oceans. Their unusual adaptations, from the molecular to the macroscopic level, contribute to their ecological success and biogeochemical importance. Trichodesmium fixes nitrogen gas (N2) under fully aerobic conditions while photosynthetically evolving oxygen. Its temporal pattern of N2 fixation results from an endogenous daily cycle that confines N2 fixation to daylight hours. Trichodesmium colonies provide a unique pelagic habitat that supports a complex assemblage of consortial organisms. These colonies often represent a large fraction of the plant biomass in tropical, oligotrophic waters and contribute substantially to primary production. N2 fixation by Trichodesmium is likely a major input to the marine and global nitrogen cycle.
University of Tokyo1, Chugai Pharmaceutical Co.2, Kumamoto University3, Osaka University4, Japanese Foundation for Cancer Research5, Obihiro University of Agriculture and Veterinary Medicine6, Leiden University7, University of British Columbia8, University of North Carolina at Chapel Hill9, University of Oxford10
TL;DR: It is shown that targeted disruption of the MSR-A gene in mice results in a reduction in the size of atherosclerotic lesions in an animal deficient in apolipoprotein E, indicating that MSr-A may play a part in host defence against pathogens.
Abstract: Macrophage type-I and type-II class-A scavenger receptors (MSR-A) are implicated in the pathological deposition of cholesterol during atherogenesis as a result of receptor-mediated uptake of modified low-density lipoproteins (mLDL)1–6. MSR-A can bind an extraordinarily wide range of ligands, including bacterial pathogens7, and also mediates cation-independent macrophage adhesion in vitro8. Here we show that targeted disruption of the MSR-A gene in mice results in a reduction in the size of atherosclerotic lesions in an animal deficient in apolipoprotein E. Macrophages from MSR-A-deficient mice show a marked decrease in mLDL uptake in vitro, whereas mLDL clearance from plasma occurs at a normal rate, indicating that there may be alternative mechanisms for removing mLDL from the circulation. In addition, MSR-A-knockout mice show an increased susceptibility to infection with Listeria monocytogenes or herpes simplex virus type-1, indicating that MSR-A may play a part in host defence against pathogens.
TL;DR: Protean clinical manifestations, combined with the etiologic nonspecificity of the histologic lesions, complicate the diagnosis of specific forms of vasculitis.
Abstract: Vasculitis is inflammation of vessel walls. It has many causes, although they result in only a few histologic patterns of vascular inflammation. Vessels of any type in any organ can be affected, a fact that results in a wide variety of signs and symptoms. These protean clinical manifestations, combined with the etiologic nonspecificity of the histologic lesions, complicate the diagnosis of specific forms of vasculitis. This is problematic because different vasculitides with indistinguishable clinical presentations have very different prognoses and treatments. For example, a patient with purpura, nephritis, and abdominal pain caused by Henoch–Schonlein purpura usually has a good prognosis . . .
TL;DR: The epidemiology and biology of the host-related factors that affect the sexual transmission of HIV and the host susceptibility and infectiousness environment biologic agent are discussed.
Abstract: Transmission through sexual contact accounts for 75 to 85 percent of the nearly 28 million infections with the human immunodeficiency virus (HIV) that have occurred so far1 The probability of infection through sexual contact, although it varies greatly, appears to be lower than that of infection through other routes of exposure (Figure 1) The variability observed among and within routes of HIV exposure depends partly on the viral dose and also on whether the virus is transmitted directly into the blood or onto a mucous membrane In addition, these differences are influenced by a variety of host factors, including both
TL;DR: The diagnostic criteria for neurofibromatosis 1 and neurof fibromaatosis 2, recommendations for the care of patients and their families at diagnosis and during routine follow-up, and the role of DNA diagnostic testing in the evaluation of these disorders are determined.
Abstract: Objective. —Neurofibromatosis 1 and neurofibromatosis 2 are autosomal dominant genetic disorders in which affected individuals develop both benign and malignant tumors at an increased frequency. Since the original National Institutes of Health Consensus Development Conference in 1987, there has been significant progress toward a more complete understanding of the molecular bases for neurofibromatosis 1 and neurofibromatosis 2. Our objective was to determine the diagnostic criteria for neurofibromatosis 1 and neurofibromatosis 2, recommendations for the care of patients and their families at diagnosis and during routine follow-up, and the role of DNA diagnostic testing in the evaluation of these disorders. Data Sources. —Published reports from 1966 through 1996 obtained by MEDLINE search and studies presented at national and international meetings. Study Selection. —All studies were reviewed and analyzed by consensus from multiple authors. Data Extraction. —Peer-reviewed published data were critically evaluated by independent extraction by multiple authors. Data Synthesis. —The main results of the review were qualitative and were reviewed by neurofibromatosis clinical directors worldwide through an Internet Web site. Conclusions. —On the basis of the information presented in this review, we propose a comprehensive approach to the diagnosis and treatment of individuals with neurofibromatosis 1 and neurofibromatosis 2.
TL;DR: Diffraction enhanced imaging is a new x-ray radiographic imaging modality using monochromatic x-rays from a synchrotron which produces images of thick absorbing objects that are almost completely free of scatter.
Abstract: Diffraction enhanced imaging is a new x-ray radiographic imaging modality using monochromatic x-rays from a synchrotron which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantom. The contrast is based not only on attenuation but also the refraction and diffraction properties of the sample. This imaging method may improve image quality for medical applications, industrial radiography for non-destructive testing and x-ray computed tomography.
TL;DR: This paper presented preliminary evidence regarding the reliability and validity of the Multidimensional Inventory of Black Identity (MIBI), which consists of seven subscales representing three stable dimensions of African American racial identity (Centrality, Ideology, and Regard).
Abstract: The present study presents preliminary evidence regarding the reliability and validity of the Multidimensional Inventory of Black Identity (MIBI). The MIBI consists of 7 subscales representing 3 stable dimensions of African American racial identity (Centrality, Ideology, and Regard). Responses to the MIBI were collected from 474 African American college students from a predominantly African American university (n = 185) and a predominantly White university (n = 289). As the result of factor analysis, a revised 51 -item scale was developed. Evidence was found for 6 subscales. The Public Regard subscale was dropped because of poor internal consistency. Interscale correlations suggest that the MIBI is internally valid. Relationships among the MIBF subscales and race-related behavior suggest that the instrument has external validity. Descriptive statistics for the revised MIBI are provided for the entire sample as well as by school. Racial identity is one of the most heavily researched aspects of African Americans' psychological lives. Racial identity has been associated with a number of phenomena including selfesteem (Hughes & Demo, 1989; Parham & Helms, 1985; Row
TL;DR: The major problem yet to be resolved is developing usable and communicable systematic approaches to conducting metasynthesis projects that maintain the integrity of individual studies.
Abstract: There has been an accumulation of qualitative studies in recent years, but little cumulation of the understandings gained from them. Qualitative research appears endangered both by efforts to synthesize studies and by the failure to do so. Techniques used have included reciprocal translations of key metaphors and concepts and qualitative and quantitative comparative analyses to produce narrative and theoretical integrations. The major problem yet to be resolved is developing usable and communicable systematic approaches to conducting metasynthesis projects that maintain the integrity of individual studies.
TL;DR: In this article, a more holistic approach incorporating interspecific interactions and physical environmental influences would contribute to greater sustainability by reducing the uncertainty in predictions and transforming the management process to reduce the influence of pressure for greater harvest holds more immediate promise.
Abstract: The global marine fish catch is approaching its upper limit. The number of overfished populations, as well as the indirect effects of fisheries on marine ecosystems, indicate that management has failed to achieve a principal goal, sustainability. This failure is primarily due to continually increasing harvest rates in response to incessant sociopolitical pressure for greater harvests and the intrinsic uncertainty in predicting the harvest that will cause population collapse. A more holistic approach incorporating interspecific interactions and physical environmental influences would contribute to greater sustainability by reducing the uncertainty in predictions. However, transforming the management process to reduce the influence of pressure for greater harvest holds more immediate promise.
TL;DR: In this article, the authors present two conceptual frameworks to aid managerial understanding and focus research efforts on customer participation in service experience development, and discuss three major roles of customers in the service delivery process.
Abstract: Focuses on the roles of customers in creating quality and productivity in service experiences. Presents two conceptual frameworks to aid managerial understanding and focus research efforts on customer participation. The first framework captures levels of customer participation across different types of services. The second discusses three major roles of customers in the service delivery process. Two examples of the concepts are presented ‐ one in a weight loss context and the other in a mammography screening setting. Both are based on empirical research and illustrate specific applications of customers’ roles in creating the service experience.
TL;DR: In this paper, the role of independent outside directors in a firm's independent board during a tender offer was examined, and the authors concluded that independent outside board members enhance target shareholders' gains from the tender offer.
TL;DR: HIV-1-control programmes, which include detection and treatment of STDs in patients already infected with HIV-1, may help to curb the epidemic and targeting of gonococcal urethritis may be a particularly effective strategy.
TL;DR: In this article, atmospheric deposition (AD) and groundwater (GW) discharge are of considerable and growing importance for oceanic primary production and contribute from 300 to > 1,000 mg N m -2 yr -I lo coastal waters as the biologically available forms NO, NHJNH, and dissolved organic N.
Abstract: Nitrogen-limited csluaries, shallow coastal waters, and continental shelf ivatcrs cover only 15% of the world’s ocean area, but account for nearly half the global oceanic primary production. This disproportionality is partly attributed to accelerating and geographically expanding anthropogenic N h-lading and eutrophication. Among accelerating N inputs, atmospheric deposition (AD) (as wet- and dryfall) and groundwater (GW) discharge are of considerable and growing importance. AD contributes from 300 to > 1,000 mg N m -2 yr -I lo coastal waters as the biologically available forms NO, , NHJNH,‘, and dissolved organic N. GW-N inputs have not been extensively characterized and quantified but in certain regions may be comparable to 11D. AD and GW can -jointly account from 20 lo >50% of total exogenous, or “new,” N loading and may uniquely mediate coastal eutrophication by bypassing estuarine filters of terrigenous N inputs. Direct AD and offshore GW inputs may impact harmful algal bloom dynamics of coastal and pelagic waters downwind of emissions and downstream of discharges. Example include Norlh American Atlantic coastal waters, the Baltic and North Seas, the western Mediterranean, and the Yellow Sea. Impacts include enhanced N availability and alteration of stoicl-iometric ratios of nutrients (N, P, Si). Trace metal enrichment (e.g. Fe) in AD and GW may interact synergistically with N to stimulate coastal production. Growing urban, industrial, and agricultural AD and GW inputs to coastal and offshore waters may be linked to a purported expansion of harmful algal blooms. Nitrogen limitation characterizes large segments of the world’s oceanic, coastal, and estuarine waters (Dugdale 1967; Ryther and Dunstan 1971; Codispoti 1989). The rate of biologically available nitrogen supply to these waters is a key control of primary production and resultant trophic state (Ryther and Dunstan 197 1; Eppley and Peterson 1979; D’Elia et al. 1986; Nixon 1986, 1988). Biologically available N originates from either endogenous or exogenous sources. Primary production supported by endogenous N is referred to as “regenerated production,” while exogenous production is termed “new” production. In deep (>200 m) oceanic regions away from land masses, much of the primary production is dependent on regenerated ammonium derived from organic matter mineralization. Exceptions include production supported by N, fixation or NO, from upwelled deep water, both of which are considered new N sources. Coastal and estuarine environments are heavily influenced by new N, supplied either naturally by weathering of minerals, decomposition, lightning, and geothermal emissions or anthropogenically. Anthropogenic sources include urban and
TL;DR: The generalized partially linear single-index model (GPLSIM) as discussed by the authors is a nonparametric generalized linear model for regression of a response Y on predictors (X, Z) with conditional mean function based on a linear combination of X, Z, where η 0(·) is an unknown function.
Abstract: The typical generalized linear model for a regression of a response Y on predictors (X, Z) has conditional mean function based on a linear combination of (X, Z). We generalize these models to have a nonparametric component, replacing the linear combination α T 0X + β T 0Z by η0(α T 0X) + β T 0Z, where η0(·) is an unknown function. We call these generalized partially linear single-index models (GPLSIM). The models include the “single-index” models, which have β0 = 0. Using local linear methods, we propose estimates of the unknown parameters (α0, β0) and the unknown function η0(·) and obtain their asymptotic distributions. Examples illustrate the models and the proposed estimation methodology.
TL;DR: In this paper, the authors investigated the Rosenberg Self-Esteem Scale, a self-report instrument for evaluating individual self-esteem, using item response theory, and found that the 10 items of the Rosenberg self-esteem scale are not equally discriminating and are differentially related to selfesteem.
Abstract: The Rosenberg Self-Esteem Scale, a widely used self-report instrument for evaluating individual self-esteem, was investigated using item response theory. Factor analysis identified a single common factor, contrary to some previous studies that extracted separate Self-Confidence and Self-Depreciation factors. A unidimensional model for graded item responses was fit to the data. A model that constrained the 10 items to equal discrimination was contrasted with a model allowing the discriminations to be estimated freely. The test of significance indicated that the unconstrained model better fit the data-that is, the 10 items of the Rosenberg Self-Esteem Scale are not equally discriminating and are differentially related to self-esteem. The pattern of functioning of the items was examined with respect to their content, and observations are offered with implications for validating and developing future personality instruments.
TL;DR: Activation of Cdc42 and Rac1 disrupts the normal polarization of mammary epithelial cells in a collagenous matrix, and promotes motility and invasion, and requires phosphatidylinositol-3-OH kinase (PI(3)K).
Abstract: Transformation of mammary epithelial cells into invasive carcinoma results in alterations in their integrin-mediated responses to the extracellular matrix, including a loss of normal epithelial polarization and differentiation, and a switch to a more motile, invasive phenotype. Changes in the actin cytoskeleton associated with this switch suggest that the small GTPases Cdc42 and Rac, which regulate actin organization, might modulate motility and invasion. However, the role of Cdc42 and Rac1 in epithelial cells, especially with respect to integrin-mediated events, has not been well characterized. Here we show that activation of Cdc42 and Rac1 disrupts the normal polarization of mammary epithelial cells in a collagenous matrix, and promotes motility and invasion. This motility does not require the activation of PAK, JNK, p70 S6 kinase, or Rho, but instead requires phosphatidylinositol-3-OH kinase (PI(3)K). Further, direct PI(3)K activation is sufficient to disrupt epithelial polarization and induce cell motility and invasion. PI(3)K inhibition also disrupts actin structures, suggesting that activation of PI(3)K by Cdc42 and Rac1 alters actin organization, leading to increased motility and invasiveness.
TL;DR: Living in deprived neighborhoods was associated with increased prevalence of coronary heart disease and increased levels of risk factors, with associations generally persisting after adjustment for individual-level variables.
Abstract: The authors investigated whether neighborhood socioeconomic characteristics are associated with coronary heart disease prevalence and risk factors, whether these associations persist after adjustment for individual-level social class indicators, and whether the effects of individual-level indicators vary across neighborhoods. The study sample consisted of 12,601 persons in four US communities (Washington County, Maryland; Forsyth County, North Carolina; Minneapolis, Minnesota; and Jackson, Mississippi) participating in the baseline examination of the Atherosclerosis Risk in Communities Study (1987-1989). Neighborhood characteristics were obtained from 1990 US Census block-group measures. Multilevel models were used to estimate associations with neighborhood variables after adjustment for individual-level indicators of social class. Living in deprived neighborhoods was associated with increased prevalence of coronary heart disease and increased levels of risk factors, with associations generally persisting after adjustment for individual-level variables. Inconsistent associations were documented for serum cholesterol and disease prevalence in African-American men. For Jackson African-American men living in poor neighborhoods, coronary heart disease prevalence decreased as neighborhood characteristics worsened. Additionally, in African-American men from Jackson, low social class was associated with increased serum cholesterol in "richer" neighborhoods but decreased serum cholesterol in "poorer" neighborhoods. Neighborhood environments may be one of the pathways through which social structure shapes coronary heart disease risk.
University of Tennessee Health Science Center1, University of Louisville2, Pennsylvania State University3, Houston Methodist Hospital4, University of Kentucky5, Erie County Medical Center6, University of Arkansas at Little Rock7, University of Cincinnati8, University of California, Davis9, Ohio State University10, Harvard University11, St. John's Hospital12, University of California, San Diego13, Vanderbilt University14, MedStar Washington Hospital Center15, University Medical Center16, University of South Carolina17, Allegheny General Hospital18, Baylor College of Medicine19, University of Southern California20, Wright State University21, University of Western Ontario22, University of Alberta23, Gundersen Health System24, Medical College of Wisconsin25, Dartmouth College26, Boston University27, Sparrow Health System28, State University of New York Upstate Medical University29, Saint Louis University30, University of Missouri31, University of Texas Medical Branch32, University of North Carolina at Chapel Hill33, Mayo Clinic34, Carolinas Medical Center35, Cedars-Sinai Medical Center36, Rutgers University37, Henry Ford Health System38, University of Manitoba39, University of Texas Southwestern Medical Center40, University of California, San Francisco41, University of South Alabama42, University of Tennessee43
TL;DR: Although newer diagnostic techniques are being applied, at this time aortography remains the diagnostic standard; bypass techniques, which provide distal aortic perfusion, produced significantly lower paraplegia rates than the clamp and sew approach.
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.