Decreased activity of inducible nitric oxide synthase type 2 and modulation of the expression of glutathione S-transferase alpha, bcl-2, and metallothioneins during the differentiation of CaCo-2 cells.

Reactive oxygen species modulate the cell growth of a wide variety of mammalian cells. To determine whether oxidative metabolism is altered during the differentiation process, we studied the expression of pro- and antioxidant proteins in proliferating and differentiated CaCo-2 cells, a human colon adenocarcinoma cell line. Nitric oxide synthase type 2 (iNOS) produces nitric oxide (NO). Depending on its rate of synthesis, NO may either promote cellular and DNA damage or reduce the ability of other free radicals to induce cell injury. Using Western and Northern blot analysis and arginine conversion assay, we demonstrate that the expression of iNOS decreases when cells undergo differentiation. This biological event entails a diminished production of NO metabolites and correlates with the loss of activation of soluble guanylate cyclase activity. In differentiated cells, a 2-fold down-regulation of the nuclear factor kappa B activity was observed, suggesting that nuclear factor kappa B could be one of the iNOS gene regulatory factors in the CaCo-2 model. In parallel, we studied the expression of other antioxidant proteins including glutathione S-transferase alpha (GST alpha), bcl-2, and the metallothioneins (MTs). We show that the protein levels of GST alpha and MT increase during the differentiation of CaCo-2 cells, whereas bcl-2 levels decrease. Our investigation indicates that the expression of iNOS, GST alpha, bcl-2, and MT is associated with the enterocytic differentiation. The shift in the expression of specific antioxidant genes during CaCo-2 cell differentiation may occur to avoid alterations in the cell redox potential

The Role of Interferon Regulatory Factor-1 and Interferon Regulatory Factor-2 in IFN-γ Growth Inhibition of Human Breast Carcinoma Cell Lines

Interferon (IFN) regulatory factor-1 (IRF-1) and IRF-2 play opposing roles in the regulation of many IFN-γ-inducible genes. To investigate the signal transduction pathway in response to IFN-γ in light of differences in growth effects, we selected four human breast carcinoma cell lines based on a spectrum of growth inhibition by IFN-γ. MDA468 growth was markedly inhibited by IFN-γ, and it showed substantial induction of IRF-1 mRNA but little IRF-2 induction. SKBR3 showed little growth inhibition and little induction of IRF-1 mRNA but significant induction of IRF-2 mRNA. HS578T and MDA436 growth inhibition and IRF-1/IRF-2 induction were intermediate. All four cell lines showed intact receptor at the cell surface and Stat1 translocation to the nucleus by immunostaining. By EMSA, there were marked differences in the induced ratio of IRF-1 and IRF-2 binding activity between the cell lines that correlated with growth inhibition. Finally, antisense oligonucleotides specific for IRF-1 attenuated IFN-γ growth inhibition in MDA436 and MDA468, confirming the direct role of IRF-1 in IFN-γ growth inhibition. Induction of IRF-1 causes growth inhibition in human breast cancer cell lines, and induction of IRF-2 can oppose this. The relative induction of IRF-1 to IRF-2 is a critical control point in IFN-γ response.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63111/1/10799900360708623.pd

In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains,Escherichia coli DH5α,Micrococcus luteusandStaphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, women 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.Peer reviewe

Measuring children's self-efficacy and proxy efficacy related to fruit and vegetable consumption

BACKGROUND: Social cognitive theory describes self-efficacy and proxy efficacy as influences on fruit and vegetable consumption (FVC). Proxy efficacy was defined as a child's confidence in his or her skills and abilities to get others to act in one's interests to provide fruit and vegetable (FV) opportunities. The purpose of this study was to develop a scale assessing children's self-efficacy and proxy efficacy for FVC at after-school programs and at home. METHODS: Elementary-aged children (n = 184) attending 7 after-school programs completed a self-efficacy questionnaire relevant to FVC. Questionnaire validity was investigated with exploratory factor analysis and mixed-model analysis of covariance. Internal consistency reliability and readability were also assessed. RESULTS: The questionnaire assessed 4 constructs: self-efficacy expectations for fruit consumption, self-efficacy expectations for vegetable consumption, proxy efficacy to influence parents to make FV available, and proxy efficacy to influence after-school staff to make FV available. Children perceiving FV opportunities in after-school had greater self-efficacy expectations for FVC and greater proxy efficacy to influence after-school staff compared to students who did not perceive FV opportunities. Children attending schools of higher socioeconomic status (SES) and less diversity were more confident they could influence their parents to make FV available than students attending lower SES and less diverse schools. Adequate internal consistency and test-retest reliabilities were established. CONCLUSIONS: Self-efficacy is a multicomponent construct that can be assessed in children using the reliable and valid instrument evaluated by the current study. © 2009, American School Health Association

Children's self-efficacy and proxy efficacy for after-school physical activity

Problem: This study evaluated the psychometric properties of a scale measuring children's self-efficacy and proxy efficacy for physical activity at after-school programs and at home. Proxy efficacy was defined as children's confidence in their skills and abilities to get adults to act in their interest to provide physical activity opportunities. Methods: Children (grades 4 through 6) attending after-school programs completed a self-efficacy questionnaire relevant to their physical activity. Factorial validity was assessed with an exploratory factor analysis (n = 107) and a confirmatory factor analysis (n = 187). Next, criterion-related validity was assessed using a mixed-model analysis of covariance with school as a random effect and children level variables as fixed effects. Internal consistency reliability was assessed using Cronbach's alpha. Results: The questionnaire assessed three separate constructs: self-efficacy to be physically active (SEPA), proxy efficacy to influence parents to provide physical activity opportunities (PEPA-P), and proxy efficacy to influence after-school staff to provide physical activity opportunities (PEPA-S). Males had greater SEPA than females. Children who perceived greater physical activity opportunities during after-school time had greater SEPA, PEPA-P, and PEPA-S than children attending schools with fewer physical activity opportunities. Children attending schools with lower concentrations of racial/ethnic diversity and higher socioeconomic status (SES) had greater PEPA-P compared to children attending greater racial/ethnic diversity and low-SES schools. Conclusions: Self-efficacy for physical activity is a multicomponent construct and can be assessed in elementary-aged children using the reliable and valid instrument confirmed in the current study. © 2009 Elsevier Ltd. All rights reserved