45 research outputs found
Adolescents' involvement in cyber bullying and perceptions of school: the importance of perceived peer acceptance for female adolescents
Young people are spending increasing amounts of time using digital technology and, as such, are at great risk of being involved in cyber bullying as a victim, bully, or bully/victim. Despite cyber bullying typically occurring outside the school environment, the impact of being involved in cyber bullying is likely to spill over to school. Fully 285 11- to 15-year-olds (125 male and 160 female, M age = 12.19 years, SD = 1.03) completed measures of cyber bullying involvement, self-esteem, trust, perceived peer acceptance, and perceptions of the value of learning and the importance of school. For young women, involvement in cyber bullying as a victim, bully, or bully/victim negatively predicted perceptions of learning and school, and perceived peer acceptance mediated this relationship. The results indicated that involvement in cyber bullying negatively predicted perceived peer acceptance which, in turn, positively predicted perceptions of learning and school. For young men, fulfilling the bully/victim role negatively predicted perceptions of learning and school. Consequently, for young women in particular, involvement in cyber bullying spills over to impact perceptions of learning. The findings of the current study highlight how stressors external to the school environment can adversely impact young women's perceptions of school and also have implications for the development of interventions designed to ameliorate the effects of cyber bullying
Transcriptional repression of miR-34 family contributes to p63-mediated cell cycle progression in epidermal cells
p63, a p53 family member, is highly expressed in the basal proliferative compartment of the epidermis and its expression has been correlated with the growth ability and regenerative capacity of keratinocytes. In this study we report a mechanism through which p63 maintains cell cycle progression by directly repressing miR-34a and miR-34c. In the absence of p63, increased levels of miR-34a and miR-34c were observed in primary keratinocytes and in embryonic skin, with concomitant G1-phase arrest and inhibition of the cell cycle regulators cyclin D1 and cyclin-dependent kinase 4 (Cdk4). p63 directly bound to p53-consensus sites in both miR-34a and miR-34c regulatory regions and inhibited their activity. Concomitant downregulation of miR-34a and miR-34c substantially restored cell cycle progression and expression of cyclin D1 and Cdk4. Our data indicate that specific miR-34 family members have a significant role downstream of p63 in controlling epidermal cell proliferation
Culture conditions allow selection of different mesenchymal progenitors from adult mouse bone marrow
The use of adult stem cells in tissue engineering approaches will benefit from the establishment of culture
conditions that allow the expansion and maintenance of cells with stem cellâlike activity and high differentiation
potential. In the field of adult stem cells, bone marrow stromal cells (BMSCs) are promising candidates. In the
present study, we define, for the first time, conditions for optimizing the yields of cultures enriched for specific
progenitors of bone marrow. Using four distinct culture conditions, supernatants from culture of bone fragments,
marrow stroma cell line MS-5, embryonic fibroblast cell line NIH3T3, and a cocktail of epidermal growth
factor (EGF) and platelet-derived growth factor (PDGF), we isolated four different sub-populations of murine
BMSCs (mBMSCs). These cells express a well-known marker of undifferentiated embryonic stem cells (Nanog)
and show interesting features in immunophenotype, self-renewal ability, and differentiation potency. In particular,
using NIH3T3 conditioned medium, we obtained cells that showed impairment in osteogenic and
chondrogenic differentiation while retaining high adipogenic potential during passages. Our results indicate that
the choice of the medium used for isolation and expansion of mBMSCs is important for enriching the culture of
desired specific progenitors