Review of scientific news: April 21

Although the semester at Hopkins is coming to an end, scientific efforts around the world continue to yield exciting discoveries. This week’s Science News in Review covers new technology to identify the origins of metastatic cancers, the long-term effects of pregnancy complications, new neural circuits for food motivation, and appreciation for an Amazonian butterfly.

AI can detect the origin of metastatic cancers

Metastasis occurs when cancer cells originating from one location in the body spread to other locations. Up to 5% of the origins of metastatic tumors cannot be identified.

One traditional approach to identifying the origin of metastatic cancer relies on imaging fluid samples that contain cancer cells. By identifying the characteristic morphology of specific cancer cells in fluid samples, pathologists can deduce where the tumor cells originated. However, this technique still fails to identify the origin of the cancer in some patients.

Motivated by these cases, researchers from China developed a deep learning algorithm to help pathologists identify the origins of metastatic cancers. The researchers trained the model with a large number of images, and it is now able to make highly accurate top-three predictions about the origin of metastatic cancer cells based on an image.

In 391 patients treated for cancer in the past, those whose treatment matched the model’s prediction of metastatic origin were more likely to survive.

Pregnancy complications are associated with premature death

When adverse pregnancy outcomes occur, such as preterm birth, the attention of doctors and parents is all on the baby. However, a recent study adds to a robust body of evidence that complicated pregnancies are associated with negative maternal outcomes in the long term.

The researchers examined a cohort of more than 2 million pregnancies in Sweden with adverse pregnancy outcomes. They found that pregnancy complications increased the risk of premature death, and this risk persisted even into the mother’s seventies.

Pregnancy is a physically stressful event that can amplify pre-existing health risks and introduce new risks as the body undergoes physiological changes. The researchers emphasized that pregnancies should not be studied in isolation, but instead integrated into a patient’s medical history. Furthermore, they recommend that women with adverse pregnancy outcomes receive long-term follow-up medical care.

Mapping the neural circuitry regulating nausea-induced feeding suppression

A recent study in mice identified a new neural population in the central amygdala that is specifically fired during nausea episodes. Artificial activation of ‘nausea neurons’ suppressed eating in hungry mice.

‘Appetitive’ neurons in the amygdala inhibit ‘nausea’ neurons in the presence of an appetitive stimulus. When there is a nausea-inducing stimulus, the sensory information reaches the ‘nausea neurons’ directly, bypassing the appetite inhibition.

Mapping this neural circuit has implications for the treatment of eating disorders, such as anorexia, and the side effect of cancer therapy in appetite loss.

Amazon butterfly as a rare result of hybrid speciation

Hybrid speciation refers to mating between two separate species that contribute to the creation of a new species. Offspring with parents from two different species are often infertile and eventually revert to one of the parents’ species as more interbreeding occurs over generations.

A recent study examined Heliconius elevatus, a butterfly species in the Amazon that emerged from an ancient hybrid speciation. It has established its own healthy and distinct species for at least 180,000 years. Interestingly, the new butterfly species retains 99% of the genome from one parent and only 1% of the genome from the other parent. It is that 1% that makes the difference Heliconius elevatus as a new species from its parents, because those genes control traits that facilitate mating within the species.

Heliconius elevatus shifts the pessimistic view of hybridization and serves as living proof that hybridization can be constructive and increase species diversity.