Reproducibility of CRISPR-Cas9 methods for generation of conditional mouse alleles: a multi-center evaluation.

BACKGROUND: CRISPR-Cas9 gene-editing technology has facilitated the generation of knockout mice, providing an alternative to cumbersome and time-consuming traditional embryonic stem cell-based methods. An earlier study reported up to 16% efficiency in generating conditional knockout (cKO or floxed) alleles by microinjection of 2 single guide RNAs (sgRNA) and 2 single-stranded oligonucleotides as donors (referred herein as "two-donor floxing" method). RESULTS: We re-evaluate the two-donor method from a consortium of 20 laboratories across the world. The dataset constitutes 56 genetic loci, 17,887 zygotes, and 1718 live-born mice, of which only 15 (0.87%) mice contain cKO alleles. We subject the dataset to statistical analyses and a machine learning algorithm, which reveals that none of the factors analyzed was predictive for the success of this method. We test some of the newer methods that use one-donor DNA on 18 loci for which the two-donor approach failed to produce cKO alleles. We find that the one-donor methods are 10- to 20-fold more efficient than the two-donor approach. CONCLUSION: We propose that the two-donor method lacks efficiency because it relies on two simultaneous recombination events in cis, an outcome that is dwarfed by pervasive accompanying undesired editing events. The methods that use one-donor DNA are fairly efficient as they rely on only one recombination event, and the probability of correct insertion of the donor cassette without unanticipated mutational events is much higher. Therefore, one-donor methods offer higher efficiencies for the routine generation of cKO animal models.

Vlogging Cancer: Predictors of Social Support in YouTube Cancer Vlogs.

Social support research has demonstrated the physical and psychological benefits of social support for patients, but has done little to identify successful strategies for eliciting social support. However, contemporary digital channels offer new ways to examine this issue. In particular, this study explores vlogging as a coping strategy for cancer patients and a context in which to explore predictors of online social support. A content analysis of 69 YouTube vlogs and 869 associated comments was performed. A series of multilevel binomial logistic regression analyses revealed that narrative features that position the cancer patient as protagonist-including providing an explanation of the diagnosis experience, agentive problem solving, and positive reappraisal of the situation-were associated with receiving empathic support. In contrast, moralizing pleads for audience checkups decreased the likelihood of receiving empathic support. Findings contribute to an undertheorized body of research that also has translational value for patients, doctors, and designers of supportive online spaces who might eventually recommend narrative vlogging in clinical settings.

Absence of Malat1 does not prevent DEN-induced hepatocarcinoma in mice.

Long non-coding RNAs (lncRNA) are key regulators of gene expression both at the transcriptional and post-transcriptional levels. The lncRNA metastasis associated lung adenocarcinoma transcript 1 (Malat1) is overexpressed in many types of cancer, including hepatocarcinoma, and induces cell proliferation in several cell lines in vitro. However, the direct causal effects of Malat1 on hepatocyte proliferation and liver carcinogenesis in vivo are not fully understood. To better determine the contribution of Malat1 to hepatocarcinoma oncogenesis, this study was aimed at testing the hypothesis that its absence confers resistance to the development of liver tumors. Male Malat1-/- mice and their wild-type (WT) littermates were studied one year after treatment with the genotoxic agent diethylnitrosamine (DEN), a potent inducer of liver cancer. As expected, in WT mice, Malat1 expression was significantly higher in hepatic tumors than in healthy liver regions. Altered hepatic mRNA levels of Ki67, HDAC3, NFκB and p27 were observed in DEN-treated Malat1-/- mice. Despite this, these mice were characterized by similar liver weight, prevalence of tumors, and histological features compared to those of their WT littermates. In parallel, plasma lipids and glucose homeostasis did not significantly differ between DEN-treated groups. These findings support a role for Malat1 as a marker of liver carcinogenesis, but also suggest that its role in the regulation of hepatocyte hyperproliferation in mice is either minimal or masked by redundant and/or overwhelming mechanisms.

A mixed-methods randomized controlled trial of financial incentives and peer networks to promote walking among older adults.

BACKGROUND: Financial incentives and peer networks could be delivered through eHealth technologies to encourage older adults to walk more. METHODS: We conducted a 24-week randomized trial in which 92 older adults with a computer and Internet access received a pedometer, daily walking goals, and weekly feedback on goal achievement. Participants were randomized to weekly feedback only (Comparison), entry into a lottery with potential to earn up to $200 each week walking goals were met (Financial Incentive), linkage to four other participants through an online message board (Peer Network), or both interventions (Combined). Main outcomes were the proportion of days walking goals were met during the 16-week intervention and 8-week follow-up. We conducted a content analysis of messages posted by Peer Network and Combined arm participants. RESULTS: During the 16-week intervention, there were no differences in the proportion of days walking goals were met in the Financial Incentive (39.7%; p = .78), Peer Network (24.9%; p = .08), and Combined (36.0%; p = .77) arms compared with the Comparison arm (36.0%). During 8 weeks of follow-up, the proportion of days walking goals were met was lower in the Peer Network arm (18.7%; p = .025) but not in the Financial Incentive (29.3%; p = .50) or Combined (24.8%; p = .37) arms, relative to the Comparison arm (34.5%). Messages posted by participants focused on barriers to walking and provision of social support. CONCLUSIONS: Financial incentives and peer networks delivered through eHealth technologies did not result in older adults walking more.

Mirror, mirror on my Facebook wall: effects of exposure to Facebook on self-esteem.

Contrasting hypotheses were posed to test the effect of Facebook exposure on self-esteem. Objective Self-Awareness (OSA) from social psychology and the Hyperpersonal Model from computer-mediated communication were used to argue that Facebook would either diminish or enhance self-esteem respectively. The results revealed that, in contrast to previous work on OSA, becoming self-aware by viewing one's own Facebook profile enhances self-esteem rather than diminishes it. Participants that updated their profiles and viewed their own profiles during the experiment also reported greater self-esteem, which lends additional support to the Hyperpersonal Model. These findings suggest that selective self-presentation in digital media, which leads to intensified relationship formation, also influences impressions of the self.