Indexes of insulin resistance and secretion in obese children and adolescents

OBJECTIVE - To assess the concurrent validity of fasting indexes of insulin sensitivity and secretion in - obese prepubertal (Tanner stage 1) children and pubertal (Tanner stages 2-5) glucose tolerance test (FSIVGTT) as a criterion measure. RESEARCH DESIGN AND METHODS - Eighteen obese children and adolescents (11 girls and 7 boys, mean age 12.2 +/- 2.4 years, mean BMI 35.4 +/- 6.2 kg/m(2), mean BMI-SDS 3.5 +/- 0.5, 7 prepubertal and I I pubertal) participated in the study. All participants underwent an insulin-modified FSIVGTT on two occasions, and 15 repeated this test a third time (mean 12.9 and 12.0 weeks apart). S-i measured by the FSIVGTT was compared with homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR), quantitative insulin-sensitivity check index (QUICKI), fasting glucose-to-insulin ratio (FGIR), and fasting insulin (estimates of insulin sensitivity derived from fasting samples). The acute insulin response (AIR) measured by the FSIVGTT was compared with HOMA of percent beta-cell function (HOMA-beta%), FGIR, and fasting insulin (estimates of insulin secretion derived from fasting samples). RESULTS - There was a significant negative correlation between HOMA-IR and S-i (r = -0.89, r = -0.90, and r = -0.81, P < 0.01) and a significant positive correlation between QUICKI and S-i (r = 0.89, r = 0.90, and r = 0.81, P < 0.01) at each time point. There was a significant positive correlation between FGIR and S-i (r = 0.91, r = 0.91, and r = 0.82, P < 0.01) and a significant negative correlation between fasting insulin and S-i (r = -90, r = -0.90, and r = -0.88, P < 0.01). HOMA-beta% was not as strongly correlated with AIR (r = 0.60, r = 0.54, and r = 0.61, P < 0.05). CONCLUSIONS - HOMA-IR, QUICKI, FGIR, and fasting insulin correlate strongly with S-i assessed by the FSIVGTT in obese children and adolescents. Correlations between HOMA-β% FGIR and fasting insulin, and AIR were not as strong. Indexes derived from fasting samples are a valid tool for assessing insulin sensitivity in prepubertal and pubertal obese children.

Polymorphisms in the trace amine receptor 4 (TRAR4) gene on chromosome 6q23.2 are associated with susceptibility to schizophrenia

Several linkage studies across multiple population groups provide convergent support for a susceptibility locus for schizophrenia - and, more recently, for bipolar disorder - on chromosome 6q13-q26. We genotyped 192 European-ancestry and African American (AA) pedigrees with schizophrenia from samples that previously showed linkage evidence to 6q13-q26, focusing on the MOXD1-STX7-TRARs gene cluster at 6q23.2, which contains a number of prime candidate genes for schizophrenia. Thirty-one screening single-nucleotide polymorphisms (SNPs) were selected, providing a minimum coverage of at least 1 SNP/20 kb. The association observed with rs4305745 (P = .0014) within the TRAR4 (trace amine receptor 4) gene remained significant after correction for multiple testing. Evidence for association was proportionally stronger in the smaller AA sample. We performed database searches and sequenced genomic DNA in a 30-proband subsample to obtain a high-density map of 23 SNPs spanning 21.6 kb of this gene. Single-SNP analyses and also haplotype analyses revealed that rs4305745 and/or two other polymorphisms in perfect linkage disequilibrium (LD) with rs4305745 appear to be the most likely variants underlying the association of the TRAR4 region with schizophrenia. Comparative genomic analyses further revealed that rs4305745 and/or the associated polymorphisms in complete LD with rs4305745 could potentially affect gene expression. Moreover, RT-PCR studies of various human tissues, including brain, confirm that TRAR4 is preferentially expressed in those brain regions that have been implicated in the pathophysiology of schizophrenia. These data provide strong preliminary evidence that TRAR4 is a candidate gene for schizophrenia; replication is currently being attempted in additional clinical samples.

The importance of modelling heterogeneity in complex disease: application to NIMH Schizophrenia Genetics Initiative data

As for other complex diseases, linkage analyses of schizophrenia (SZ) have produced evidence for numerous chromosomal regions, with inconsistent results reported across studies. The presence of locus heterogeneity appears likely and may reduce the power of linkage analyses if homogeneity is assumed. In addition, when multiple heterogeneous datasets are pooled, intersample variation in the proportion of linked families ( a) may diminish the power of the pooled sample to detect susceptibility loci, in spite of the larger sample size obtained. We compare the significance of linkage. findings obtained using allele- sharing LOD scores ( LODexp) - which assume homogeneity - and heterogeneity LOD scores ( HLOD) in European American and African American NIMH SZ families. We also pool these two samples and evaluate the relative power of the LODexp and two different heterogeneity statistics. One of these ( HLOD- P) estimates the heterogeneity parameter a only in aggregate data, while the second ( HLOD- S) determines a separately for each sample. In separate and combined data, we show consistently improved performance of HLOD scores over LODexp. Notably, genome-wide significant evidence for linkage is obtained at chromosome 10p in the European American sample using a recessive HLOD score. When the two samples are combined, linkage at the 10p locus also achieves genome-wide significance under HLOD- S, but not HLOD- P. Using HLOD- S, improved evidence for linkage was also obtained for a previously reported region on chromosome 15q. In linkage analyses of complex disease, power may be maximised by routinely modelling locus heterogeneity within individual datasets, even when multiple datasets are combined to form larger samples.

A comparison of body-image dissatisfaction and eating disturbance among Australian and Hong Kong women

The current cross-cultural study was designed to test the validity of a biopsychosocial mediation model which hypothesized that a variety of biological, psychological and social variables would have their mode of action upon eating disturbance through the mediation of body-image dissatisfaction. The biopsychosocial variables examined were body mass, self-esteem, weight-related teasing, previous dieting and sociocultural influences. Forty-eight Hong Kong and 100 Australian females aged 17-28 years were assessed. Results revealed no significant difference between the groups of women in levels of body dissatisfaction and eating disturbance; however, different variables in the biopsychosocial model appeared to have contributed to their predisposition to these conditions. The findings suggest that there appear to exist important cultural differences in various aspects of dieting and body image in young women. Implications for prevention, treatment and future research are discussed. Copyright (c) 2005 John Wiley & Sons, Ltd and Eating Disorders Association.

A golden age of human pigmentation genetics

The zebrafish golden mutation is characterized by the production of small and irregular-shaped melanin granules, resulting in a lightening of the pigmented lateral stripes of the animal. The recent positional cloning and localization of the golden gene, combined with genotype-phenotype correlations of alleles of its human orthologue (SLC24A5) in African-American and African-Caribbean populations, provide insights into the genetic and molecular basis of human skin colour. SLC24A5 promotes melanin deposition through maturation of the melanosome, highlighting the importance of ion-exchange in the function of this organelle.

Diversity of pigmentation in cultured human melanocytes is due to differences in the type as well as quantity of melanin

Cultured human melanocytes differ tremendously in visual pigmentation, and recapitulate the pigmentary phenotype of the donor's skin. This diversity arises from variation in type as well as quantity of melanin produced. Here, we measured contents of eumelanin (EM) and pheomelanin (PM) in 60 primary human melanocyte cultures (51 neonatal and nine adults), and correlated some of these values with the respective activity and protein levels of tyrosinase, and the melanocortin-1 receptor (MC1R) genotype. Melanocytes were classified into four phenotypes (L, L+, D, D+) as depicted by visual pigmentation using light microscopy, and by the pigmentary phenotype of the donor's skin. There were large differences in total melanin (TM) and EM, which increased progressively for L, L+, D and D+ melanocytes. TM content, the sum of EM and PM, showed a good correlation with TM measured spectrophotometrically, and with the activity and protein levels of tyrosinase. Log EM/PM ratio did not correlate with MC1R genotype. We conclude that: (i) EM consistently correlates with the visual phenotype; (ii) lighter melanocytes tend to be more pheomelanic in composition than darker melanocytes; (iii) in adult melanocyte cultures, EM correlates with the ethnic background of the donors (African-American > Indian > Caucasian); and (iv) MC1R loss-of-function mutations do not necessarily alter the phenotype of cultured melanocytes.

Evaluating the properties of a stage-specific self-efficacy scale for physical activity using classical test theory, confirmatory factor analysis and item response modeling

The purpose of this paper was to evaluate the psychometric properties of a stage-specific selfefficacy scale for physical activity with classical test theory (CTT), confirmatory factor analysis (CFA) and item response modeling (IRM). Women who enrolled in the Women On The Move study completed a 20-item stage-specific self-efficacy scale developed for this study [n = 226, 51.1% African-American and 48.9% Hispanic women, mean age = 49.2 (67.0) years, mean body mass index = 29.7 (66.4)]. Three analyses were conducted: (i) a CTT item analysis, (ii) a CFA to validate the factor structure and (iii) an IRM analysis. The CTT item analysis and the CFA results showed that the scale had high internal consistency (ranging from 0.76 to 0.93) and a strong factor structure. Results also showed that the scale could be improved by modifying or eliminating some of the existing items without significantly altering the content of the scale. The IRM results also showed that the scale had few items that targeted high self-efficacy and the stage-specific assumption underlying the scale was rejected. In addition, the IRM analyses found that the five-point response format functioned more like a four-point response format. Overall, employing multiple methods to assess the psychometric properties of the stage-specific self-efficacy scale demonstrated the complimentary nature of these methods and it highlighted the strengths and weaknesses of this scale.

Talking about depression:an analogue study of physician gender and communication style on patient disclosures

Objectives: To disentangle the effects of physician gender and patient-centered communication style on patients' oral engagement in depression care. Methods: Physician gender, physician race and communication style (high patient-centered (HPC) and low patient-centered (LPC)) were manipulated and presented as videotaped actors within a computer simulated medical visit to assess effects on analogue patient (AP) verbal responsiveness and care ratings. 307 APs (56% female; 70% African American) were randomly assigned to conditions and instructed to verbally respond to depression-related questions and indicate willingness to continue care. Disclosures were coded using Roter Interaction Analysis System (RIAS). Results: Both male and female APs talked more overall and conveyed more psychosocial and emotional talk to HPC gender discordant doctors (all p <.05). APs were more willing to continue treatment with gender-discordant HPC physicians (p <.05). No effects were evident in the LPC condition. Conclusions: Findings highlight a role for physician gender when considering active patient engagement in patient-centered depression care. This pattern suggests that there may be largely under-appreciated and consequential effects associated with patient expectations in regard to physician gender that these differ by patient gender. Practice implications: High patient-centeredness increases active patient engagement in depression care especially in gender discordant dyads. © 2014.

Environmental lead contamination in Miami inner-city area

The purpose of the study was to evaluate the magnitude of environmental lead contamination in the downtown area of Miami. Lead inspections took place at 121 homes in Little Haiti and Liberty City and involved the collection ofrepresentative samples from floors, window wells, tap water, soil and air. Community health workers (CHWs) trained in interview and safety techniques went from door to door to enlist participation. On-site investigations were tailored to areas most utilized by children underthe age of6 years. The presence of lead-containing paint was also investigated in situ via X-ray fluorescence (XRF) analysis. Results: Of the sampling areas, the window wells area had the most abundant occurrence of lead. On analysis, 24% of sites returned window well samples with lead levels above Department of Housing and Urban Development (HUD) guidelines. Of the soil samples, the playgrounds around the house had the highest concentration of lead. Soil sampling demonstrated that 27.5% of sites returned samples with lead levels (400 to 1600 ppm) inexcess of HUD/Environmental Protection Agency (EPA) standards. Positive XRF readings in one or more components were returned by 18% of sites. Conclusions: More than half of the houses in these two neighborhoods exhibited unacceptably high levels of lead dust and soil in areas where children live and play. Limitations of this study did not allow the assessment of how many children in this area are affected. A more comprehensive study including other areas of Miami-Dade County with older housing stock is recommended.

Using structural equation modeling to assess two theoretical models that explain dropout

This study evaluated the relative fit of both Finn's (1989) Participation-Identification and Wehlage, Rutter, Smith, Lesko and Fernandez's (1989) School Membership models of high school completion to a sample of 4,597 eighth graders taken from the National Educational Longitudinal Study of 1988, (NELS:88), utilizing structural equation modeling techniques. This study found support for the importance of educational engagement as a factor in understanding academic achievement. The Participation-Identification model was particularly well fitting when applied to the sample of high school completers, dropouts (both overall and White dropouts) and African-American students. This study also confirmed the contribution of school environmental factors (i.e., size, diversity of economic and ethnic status among students) and family resources (i.e., availability of learning resources in the home and parent educational level) to students' educational engagement. Based on these findings, school social workers will need to be more attentive to utilizing macro-level interventions (i.e., community organization, interagency coordination) to achieve the organizational restructuring needed to address future challenges. The support found for the Participation-Identification model supports a shift in school social workers' attention from reactive attempts to improve the affective-interpersonal lives of students to proactive attention to their academic lives. The model concentrates school social work practices on the central mission of schools, which is educational engagement. School social workers guided by this model would be encouraged to seek changes in school policies and organization that would facilitate educational engagement. ^

Microvariation at the human D1S80 locus

Microvariant allelic polymorphisms have been known since 1966 when Harris, Hubby and Lewontin described the huge store of genetic variation detectable at the polypeptide level. Later Jeffreys used MVR (minisatellite variant repeat) analysis to describe the variation hidden within minisatellite VNTRs and to propose a mutational mechanism.^ The questions I have asked follow these traditions: (1) How much microvariant polymorphism exists at the discrete allele minisatellite D1S80 locus? (2) Do alleles or groups of alleles associate randomly with the flanking markers to form haplotypes? (3) What mechanisms might explain mutations at this locus? What are the phylogenetic relationships among the alleles?^ The minisatellite locus D1S80 (1p35-36), GenBank sequence (Accession # D28507), is a highly polymorphic Variable Number of Tandem Repeat (VNTR) based on a 16 base core. D1S80 alleles are electrophoretically separable into discontinuous sets of equivalent length alleles. Sequence variation or minor length variation within these classes was expected: I have sought to determine the nature of this microvariant heterogeneity by sequencing nominal and variant alleles.^ Alleles were analyzed by Single-Strand Conformation Polymorphism (SSCP) analysis. Sequences were determined to ascertain whether sequence variation or size variation is the major cause of altered electrophoretic migration of microvariant D1S80 alleles. Twenty three alleles from 14 previously typed individuals were sequenced. The individuals were from African American, Caucasian, or Hispanic databases.^ A Tsp509 I restriction site, previously reported as a Hinf I flanking polymorphism, and a 3$\sp\prime$ flanking region BsoF I restriction site polymorphism were identified. There appears to be a strong association of the 5$\sp\prime$ flanking region Hinf I(+) and Tsp509 I(-) site and the 3$\sp\prime$ flanking region BsoF I(-) site with the 18 allele, while the 24 tends to be associated with the Hinf I(-), Tsp509 I(+) and BsoF I(+) sites.^ The general conclusion for this locus is clearly the closer you look, the more you find. D1S80 allelic polymorphisms are primarily due to variation in the number of repeat units and to sequence variation among repeats. The sequenced based gene tree depicts two major classes of alleles which conform to the two most common alleles, reflecting either equivalent age or population size bottlenecks. ^

Maria W. Stewart: America's first Black feminist

Maria W. Stewart was the first American-born and the first African-American woman known to address a mixed audience, from 1831 to 1833, and publish her essays and speeches. The purpose of this thesis is to examine Maria W. Stewart's acts of defiance--as the first public representation of Black Feminism: demanding that white America end slavery and grant rights to black men and women, re-appropriating the hegemonic, patriarchal codes which have significant social power by exposing their inconsistencies and deconstructing their ideologies, voicing the truth about the status of African-American women in early nineteenth-century America, and challenging Black women to become entrepreneurs and (as she did) acquire an education, establish schools, and take an active role in their community. ^

Without women: Masculinities, gay male sexual culture and sexual behaviors in Miami, Florida

Recent studies have reported alarmingly high rates of HIV infection and risky sexual behaviors among gay men in Miami, Florida. Previous research has suggested that the risky sexual behaviors of many gay men reflect the pursuit of intimacy and love, and that barriers to intimate relationships among gay men may stem from traditional masculinity norms. This dissertation examines the meanings which gay men ascribe to their sexual behaviors, as well as the intersections of those meanings with both traditional masculinity constructions and Miami's gay male sexual culture. ^ The study is based upon participant observation, print media content analysis, surveys and ethnographic interviews of a purposive snowball sample of 30 Cuban American, Puerto Rican, African American and Anglo gay men who reside in Miami-Dade County, Florida. Analysis of research questions was accomplished through grounded theory methods and descriptive and non-parametric statistics, including Pearson chi-square, Fisher's Exact and Mann-Whitney U tests. ^ The study shows that culturally-specified masculinity norms vary in the relative importance ascribed to heterosexual prowess, economic providership and competitiveness. These cultural differences appear important not only to the timing of sexual awareness and to the strength of homosexual stereotyping as effeminacy, but also to men's strategies in coming out as gay. The meanings men attributed to their sexual behaviors were, however, constructed in response to both inherited masculinity norms and the hypermasculine structure of Miami's gay male sexual culture. In addition to providing an ethnographic account of this subculture, the study elaborates men's issues relative to casual sex and committed relationships. Unprotected anal intercourse with casual partners during the previous twelve months was associated with growing up without one's father in the home, having been teased for effeminacy during childhood, being defensive about one's masculinity, not trusting men, having been cheated on by boyfriends, and believing that long-term gay male relationships are problematic. ^ It is concluded that the continuing epidemic of HIV infections among local gay men, as well as the hypermasculine form of the gay sexual subculture itself, are nihilistic symptoms embedded in the masculinist gender structure of the larger society. ^

Teacher-student relationships and the link to academic adjustment and emotional well-being in early adolescence

The role of support from teachers on the academic and emotional adjustment of a ethnically and economically diverse sample of adolescents was examined. Analyses were conducted on data from a larger study examining social networks across the transition to junior high school. Participants in the current study included 694 African-American, Hispanic-American and European-American students in grades 6 and 8 from public elementary schools in South Florida. Some of these schools are located in economically distressed areas and some are in middle income areas. Children were interviewed, and information on teacher social support resources, school stressors, risk and academic and emotional adjustment was obtained. Several significant findings emerged from the analyses. First, overall teacher support was a significant predictor of a wide range of academic and emotional adjustment outcomes. Second, teacher support compensated for low peer support on teacher rated behavior problems. Third, teacher support interacted with school stress to predict depressed affect and self esteem. Fourth, teacher support interacted with low ecological risk conditions to predict feelings of loneliness. ^

The health and nutritional status of multiethnic perimenopausal women

An integrated, dual-phase study design assessed the health and nutritional status and practices of African-American (A-A), Caribbean (A-C), and white non-Hispanic (W-A) women during perimenopause (40–55 years). During Phase I, four focus groups (n = 37) of male and female participants discussed the health and social implications of perimenopause. A conceptual framework for the main study (Phase II) was developed from the focus groups' findings, in concert with the main study's specific aims and objectives. ^ The main study, a cross-sectional survey, quantitatively assessed the health and nutritional status of a convenience sample of 109 women (25 A-A, 31 A-C and 53 W-A), who met specific eligibility criteria. Using seven instruments, sociodemographic, dietary, medical, reproductive health, health practice and anthropometric data were collected. ^ The groups were of comparable age, education, and socioeconomic status (SES). Despite these similarities, statistically significant interethnic nutritional status differences were found. Significantly more total energy and energy from fat were consumed by A-A than W-A and A-C women. Also, significantly more A-A and A-C than W-A women were overweight or obese with android-type weight patterning. ^ Overall, iron and calcium Recommended Dietary Allowances (RDA's) were not met by 35% and 68% of participants, respectively. Iron deficiency anemia was reported by 29% of participants while 33% reported heavier menstrual bleeding. Coupled with suboptimal iron intakes, this is likely to present a serious public health problem. Similarly, increased bone demineralization characteristic of perimenopause, coupled with suboptimal calcium intakes could precipitate another public health problem, osteoporosis. ^ Participants had different expectations about the role of medical care during perimenopause. Significantly more white (57%) than black (38% [A-A and AC]) women sought medical attention for symptoms. Whereas Hormone Replacement Therapy (HRT) was prescribed for 25% of them, only 13% were compliant at enrollment. ^ The trends and statistically significant findings of this study have huge public health policy implications. It is imperative that appropriate policies are formulated to ensure that America's ethnically diverse perimenopausal women have ready access to culturally appropriate care. This would optimize their health outcomes, and enhance their quality of life and productive capacities at this critical juncture of their lives. ^