20 research outputs found
Like-minded sources on Facebook are prevalent but not polarizing
Many critics raise concerns about the prevalence of ‘echo chambers’ on social media and their potential role in increasing political polarization. However, the lack of available data and the challenges of conducting large-scale field experiments have made it difficult to assess the scope of the problem 1,2. Here we present data from 2020 for the entire population of active adult Facebook users in the USA showing that content from ‘like-minded’ sources constitutes the majority of what people see on the platform, although political information and news represent only a small fraction of these exposures. To evaluate a potential response to concerns about the effects of echo chambers, we conducted a multi-wave field experiment on Facebook among 23,377 users for whom we reduced exposure to content from like-minded sources during the 2020 US presidential election by about one-third. We found that the intervention increased their exposure to content from cross-cutting sources and decreased exposure to uncivil language, but had no measurable effects on eight preregistered attitudinal measures such as affective polarization, ideological extremity, candidate evaluations and belief in false claims. These precisely estimated results suggest that although exposure to content from like-minded sources on social media is common, reducing its prevalence during the 2020 US presidential election did not correspondingly reduce polarization in beliefs or attitudes
Rectal Organoids Enable Personalized Treatment of Cystic Fibrosis
In vitro drug tests using patient-derived stem cell
cultures offer opportunities to individually select
efficacious treatments. Here, we provide a study
that demonstrates that in vitro drug responses in
rectal organoids from individual patients with cystic
fibrosis (CF) correlate with changes in two in vivo
therapeutic endpoints. We measured individual
in vitro efficaciousness using a functional assay
in rectum-derived organoids based on forskolininduced swelling and studied the correlation with
in vivo effects. The in vitro organoid responses correlated with both change in pulmonary response and
change in sweat chloride concentration. Receiver
operating characteristic curves indicated good-toexcellent accuracy of the organoid-based test for
defining clinical responses. This study indicates
that an in vitro assay using stem cell cultures can prospectively select efficacious treatments for patients
and suggests that biobanked stem cell resources
can be used to tailor individual treatments in a
cost-effective and patient-friendly manner
A phase 1 study of PARP-inhibitor ABT-767 in advanced solid tumors with BRCA1/2 mutations and high-grade serous ovarian, fallopian tube, or primary peritoneal cancer
Purpose This phase 1 study examined safety, pharmacokinetics (PK), and efficacy of the poly(ADP-ribose) polymerase (PARP) inhibitor ABT-767 in patients with advanced solid tumors and BRCA1/2 mutations or with high-grade serous ovarian, fallopian tube, or primary peritoneal cancer. Methods Patients received ABT-767 monotherapy orally until disease progression or unacceptable toxicity. Dose was escalated from 20Â mg once daily to 500Â mg twice daily (BID). Dose-limiting toxicities, recommended phase 2 dose (RP2D), food effect, objective response rate, and biomarkers predicting response were determined. Results Ninety-three patients were treated with ABT-767; 80 had a primary diagnosis of ovarian cancer. ABT-767 demonstrated dose-proportional PK up to 500Â mg BID and half-life of ~2Â h. Food had no effect on ABT-767 bioavailability. Most common grade 3/4 treatment-related adverse events were nausea, fatigue, decreased appetite, and anemia. Anemia showed dose-dependent increase. RP2D was 400Â mg BID. Objective response rate by RECIST 1.1 was 21% (17/80) in all evaluable patients and 20% (14/71) in evaluable patients with ovarian cancer. Response rate by RECIST 1.1 and/or CA-125 was 30% (24/80) in patients with ovarian cancer. Mutations in BRCA1 or BRCA2, homologous recombination deficiency (HRD), and platinum sensitivity were associated with tumor response. Median progression-free survival was longer for HRD positive (6.7Â months) versus HRD negative patients (1.8Â months) with ovarian cancer. Conclusions ABT-767 had an acceptable safety profile up to the established RP2D of 400Â mg BID and dose-proportional PK. Patients with BRCA1 or BRCA2 mutation, HRD positivity, and platinum sensitivity were more sensitive to ABT-767