The Effect of Boron-Containing Nano-Hydroxyapatite on Bone Cells

Biological Trace Element Research - Metabolic diseases or injuries damage bone structure and self-renewal capacity. Trace elements and hydroxyapatite crystals are important in the development of...     

Candidate gene studies of ADHD: a meta-analytic review

Quantitative genetic studies (i.e., twin and adoption studies) suggest that genetic influences contribute substantially to the development of attention deficit hyperactivity disorder (ADHD). Over the past 15 years, considerable efforts have been made to identify genes involved in the etiology of this disorder resulting in a large and often conflicting literature of candidate gene associations for ADHD. The first aim of the present study was to conduct a comprehensive meta-analytic review of this literature to determine which candidate genes show consistent evidence of association with childhood ADHD across studies. The second aim was to test for heterogeneity across studies in the effect sizes for each candidate gene as its presence might suggest moderating variables that could explain inconsistent results. Significant associations were identified for several candidate genes including DAT1, DRD4, DRD5, 5HTT, HTR1B, and SNAP25. Further, significant heterogeneity was observed for the associations between ADHD and DAT1, DRD4, DRD5, DBH, ADRA2A, 5HTT, TPH2, MAOA, and SNAP25, suggesting that future studies should explore potential moderators of these associations (e.g., ADHD subtype diagnoses, gender, exposure to environmental risk factors). We conclude with a discussion of these findings in relation to emerging themes relevant to future studies of the genetics of ADHD.     

Single nucleotide polymorphisms in the REG‐CTNNA2 region of chromosome 2 and NEIL3 associated with impulsivity in a Native American sample

Impulsivity is a multi‐faceted construct that, while characterized by a set of correlated dimensions, is centered around a core definition that involves acting suddenly in an unplanned manner without consideration for the consequences of such behavior. Several psychiatric disorders include impulsivity as a criterion, and thus it has been suggested that it may link a number of different behavioral disorders, including substance abuse. Native Americans (NA) experience some of the highest rates of substance abuse of all the US ethnic groups. The described analyses used data from a low‐coverage whole genome sequence scan to conduct a genome‐wide association study (GWAS) of an impulsivity phenotype in an American Indian community sample (n = 658). Demographic and clinical information were obtained using a semi‐structured interview. Impulsivity was assessed using a scale derived from the Maudsley personality inventory that combines both novelty seeking and lack of planning items. The impulsivity score was tested for association with each variant adjusted for demographic variables, and corrected for ancestry and kinship, using emmax . Simulations were conducted to calculate empirical P‐values. Genome‐wide significant findings were observed for a variant 50‐kb upstream from catenin cadherin‐associated protein, alpha 2 (CTNNA2), a neuronal‐specific catenin, in the REG gene cluster. A meta‐analysis of GWAS had previously identified common variants in CTNNA2 as being associated with excitement seeking. A second locus upstream of nei endonuclease VIII‐like 3 (NEIL3) on chromosome 4 also achieved genome‐wide significance. The association between sequence variants in these regions suggests their potential roles in the genetic regulation of this phenotype in this population.