SV40-Immortalized Human Fibroblasts as a Source of SV40 Infectious Virions

Human fibroblasts immortalized by Simian Virus 40 (SV40) are widely employed for cell and molecular biology model of study. Indeed, SV40 transmission to humans was believed to occur only under exceptional situations. The oncogenic potential of SV40 in laboratory animals is well established, whereas its involvement in human carcinogenesis is still a matter of active investigations. A recent report links SV40 exposure with the development of a brain tumor in a laboratory researcher. In previous studies, episomal viral DNA was detected in SV40 stably transformed and immortalized fibroblast cell lines. In this study, we report molecular and biological characterizations of SV40 DNA in human fibroblast cells. Our results indicate that SV40 is able to establish a persistent infection in long-term immortalized human fibroblasts, resulting in the production of an infectious viral progeny, which is able to infect both monkey and human cells. These data indicate that SV40-immortalized human fibroblasts may represent a source of SV40 infection. To avoid the SV40 infection, careful attention should be given by operators to this SV40-cell model of study

Parent-child positive touch: Gender, age and task differences.

This study examined gender, age, and task differences in positive touch and physical proximity during mother-child and father-child conversations. Sixty-five Spanish mothers and fathers and their 4- (M = 53.50 months, SD = 3.54) and 6-year-old (M = 77.07 months, SD = 3.94) children participated in this study. Positive touch was examined during a play-related storytelling task and a reminiscence task (conversation about past emotions). Fathers touched their children positively more frequently during the play-related storytelling task than did mothers. Both mothers and fathers were in closer proximity to their 6-year-olds than their 4-year-olds. Mothers and fathers touched their children positively more frequently when reminiscing than when playing. Finally, 6-year-olds remained closer to their parents than did 4-year-olds. Implications of these findings for future research on children’s socioemotional development are discussed