Cross-sectional associations between variations in ankle shape by statistical shape modeling, injury history, and race : the Johnston County Osteoarthritis Project

Rheumatology Research Foundation Medical Student Preceptorship Award (Lateef/Nelson), NIAMS K23 AR061406 (Nelson); NIH/NIAMS P60AR064166 and U01DP003206 (Jordan/Renner), NIH/NIAMS R01AR067743 (Golightly). The funders had no role in study design; collection, analysis, or interpretation of data; writing the manuscript or the decision to submit for publication.Peer reviewedPublisher PD

Quantifying engineered nanomaterial toxicity: comparison of common cytotoxicity and gene expression measurements

BACKGROUND: When evaluating the toxicity of engineered nanomaterials (ENMS) it is important to use multiple bioassays based on different mechanisms of action. In this regard we evaluated the use of gene expression and common cytotoxicity measurements using as test materials, two selected nanoparticles with known differences in toxicity, 5 nm mercaptoundecanoic acid (MUA)-capped InP and CdSe quantum dots (QDs). We tested the effects of these QDs at concentrations ranging from 0.5 to 160 µg/mL on cultured normal human bronchial epithelial (NHBE) cells using four common cytotoxicity assays: the dichlorofluorescein assay for reactive oxygen species (ROS), the lactate dehydrogenase assay for membrane viability (LDH), the mitochondrial dehydrogenase assay for mitochondrial function, and the Comet assay for DNA strand breaks. RESULTS: The cytotoxicity assays showed similar trends when exposed to nanoparticles for 24 h at 80 µg/mL with a threefold increase in ROS with exposure to CdSe QDs compared to an insignificant change in ROS levels after exposure to InP QDs, a twofold increase in the LDH necrosis assay in NHBE cells with exposure to CdSe QDs compared to a 50% decrease for InP QDs, a 60% decrease in the mitochondrial function assay upon exposure to CdSe QDs compared to a minimal increase in the case of InP and significant DNA strand breaks after exposure to CdSe QDs compared to no significant DNA strand breaks with InP. High-throughput quantitative real-time polymerase chain reaction (qRT-PCR) data for cells exposed for 6 h at a concentration of 80 µg/mL were consistent with the cytotoxicity assays showing major differences in DNA damage, DNA repair and mitochondrial function gene regulatory responses to the CdSe and InP QDs. The BRCA2, CYP1A1, CYP1B1, CDK1, SFN and VEGFA genes were observed to be upregulated specifically from increased CdSe exposure and suggests their possible utility as biomarkers for toxicity. CONCLUSIONS: This study can serve as a model for comparing traditional cytotoxicity assays and gene expression measurements and to determine candidate biomarkers for assessing the biocompatibility of ENMs.1R01GM84702-01 - National Institute of General Medical Science

Weight Status as a Mediator of the Association Between Preschool Extraversion and Adolescent Restrained Eating

Objectives To determine the longitudinal association between preschool extraversion and weight/dieting outcomes in adolescence. Methods Children (N = 180) were recruited as part of a longitudinal study, with child temperament assessed in preschool (age 5.25 years), weight assessed in 2nd grade and early adolescence, and eating outcomes assessed in early adolescence (mean age = 12.02 years). Results Preschoolers high in extraversion were significantly more likely to have higher body mass index z-scores (zBMI) and more restrained eating behaviors in adolescence. zBMI was found to mediate the relationship between extraversion and restrained eating, such that children with high levels of extraversion were more likely to have higher zBMI in adolescence and, owing to this higher weight status, to engage in more restrained eating. Conclusions Temperament is an important predictor of later maladaptive weight/dieting outcomes in adolescence, making it a potentially important early factor to consider in weight management interventions

Measurement of Differentially Methylated INS DNA Species in Human Serum Samples as a Biomarker of Islet β Cell Death

The death of islet β cells is thought to underlie the pathogenesis of virtually all forms of diabetes and to precede the development of frank hyperglycemia, especially in type 1 diabetes. The development of sensitive and reliable biomarkers of β cell death may allow for early therapeutic intervention to prevent or delay the development of diabetes. Recently, several groups including our own have reported that cell-free, differentially methylated DNA encoding preproinsulin (INS) in the circulation is correlated to β cell death in pre-type 1 diabetes and new-onset type 1 diabetes. Here, we present a step-by-step protocol using digital PCR for the measurement of cell-free INS DNA that is differentially methylated at cytosine at position -69 bp (relative to the transcriptional start site). We demonstrate that the assay can distinguish between methylated and unmethylated cytosine at position -69 bp, is linear across several orders of magnitude, provides absolute quantitation of DNA copy numbers, and can be applied to samples of human serum from individuals with new-onset type 1 diabetes and disease-free controls. The protocol described here can be adapted to any DNA species for which detection of differentially methylated cytosines is desired, whether from circulation or from isolated cells and tissues, and can provide absolute quantitation of DNA fragments