How we know: the rise of evidence-based medicine

Hello Nature readers,
Today we discover a breakthrough for lab-grown sperm, hear that the NSF plans to cut core science programmes to fund a White House initiative and explore how evidence changed the world.

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Researchers inch toward lab-grown sperm

Scientists have successfully engineered human blood cells so they transform into immature sperm, and incubated these cells in a tiny pouch grown on a mouse’s kidney. The blood cells were reprogrammed into induced pluripotent stem cells, which the team could ‘coax’ into embryonic cells that can give rise to eggs or sperm. The researchers then mixed the immature cells with non-reproductive cells found in the testicles of developing mice, which provide the environment to support sperm development. The procedure is a step toward eventually making mature sperm cells in the lab.

Preprints unchanged by peer review

The central conclusions of biomedical preprints rarely change during the peer review process, according to a study of more than 70,000 preprints. The study, which is itself currently a preprint, found that almost 40% of main conclusions were unchanged between preprint and journal-published versions of paper abstracts, and another 50% underwent only minor revisions. The authors say the findings suggest that preprints are a reliable source of information, although some scientists say the finding should be interpreted more cautiously. The study only included preprints that went on to be published in a journal, so didn’t assess the veracity of unpublished preprints.

NSF plans cuts to core science

The US National Science Foundation (NSF) is planning to expropriate money from its core science programmes to fund an initiative from the White House Office of Science and Technology Policy (OSTP), say NSF staff members and an internal NSF ledger seen by Nature. The move would force the agency to rescind funding for research proposals that are nearly finalized. The OSTP did not respond to Nature’s request for comment, nor did the offices of the legislators that oversee the NSF’s spending plans. An NSF spokesperson denied reports that the funds would be redirected to a handful of so-called ‘X-Labs’ that focus on applied research. NSF staff members who spoke to Nature say they fear retaliation if they speak out, and are not allowed to pass on what they know to researchers. “We don’t know where the money’s going or what’s going on,” one said. “We cannot communicate to the community at all. We’re forbidden.”

Hunger chose Hannibal’s Alps route

Hannibal’s history-making crossing of the Alps probably went via the Col de la Traversette — because otherwise his army would have starved. The almost 3,000-metre-high pass is the most energy-efficient route across the Alps. Still, researchers calculated that the 15-day traverse would have required more than 230 tonnes of food and supplies for the Carthaginian army of 46,000 men, 7,000 horses and 37 war elephants.

How evidence changed the world

In Beyond Belief, science journalist and Nature editor Helen Pearson charts the rise of evidence-based medicine and explores how rigorous research has transformed health and social policy. Pearson shares examples of success stories, in which solid evidence overturned bad practices, and the people behind them, many of whom were treated as mavericks for championing randomized trials. “Anyone can read and enjoy the book, yet there are nuggets for experienced readers,” writes public-policy researcher Peter John in his review. “The author writes as a believer, and her passion is engaging.”

Podcast: Hello, Dolly

In this week’s Briefing Chat, I joined host Benjamin Thompson to discuss the legacy of Dolly the sheep; the first mammal cloned from an adult cell. And we got excited about the first real-time observations of a mid-ocean ridge splitting apart.