How jet lag induces cancer

For years, the main cause of liver cancer was heavy drinking but that is no more the case. Non-alcoholic fatty liver disease is now the prime force behind most liver cancers. Obesity is widely been blamed for this but there is also evidence suggesting that disrupted circadian rhythms play a part too. How and why circadian disruption has this effect has been a mystery but now a new study is revealing details.

The researchers worked with mice and found that jet lag induced the livers of the animals to produce and store far more fat than they otherwise would. Worse, they noticed that jet lag drove the mice to produce compounds that both induced mutations and helped their liver cells to replicate rapidly. The combination of increased cellular replication with mutagens around proved utterly toxic and ultimately produced cancer cells. This is unpleasant stuff but the researchers point out that understanding the chemical pathways responsible for spawning liver cancer can give us the edge as we attempt to prevent this terrible disease. You can read more in The Economist article that I wrote on this here. 

Orca research explains menopause

Image courtesy of NOAA.

Why menopause happens in some animals is a longstanding evolutionary mystery. Many biologists have argued that menopause forces grandmothers to support the offspring of their own children rather than continuing to have kids of their own but number-crunchers have dismissed this "grandmother hypothesis" on the grounds that the magnitude of the benefits granted by grandmotherly support are insufficient to account for the monumental genetic cost of giving up reproduction. In recent years an alternative theory has emerged suggesting that menopause reduces the cost of inter-generational reproductive conflict by preventing weakening older females from becoming pregnant and using up valuable resources that could go to their actively reproducing daughters. It is a nice idea but proving it has been difficult. Now a team is demonstrating that this theory is correct by cleverly making use of an animal that lives for decades after menopause sets in: the orca.

The researchers tapped into a long-term dataset on wild resident killer whales where females frequently live for 20 to 40 years after menopause begins. Using 43 years of orca data they were able to show that when mothers and daughters co-breed, mortality in calves from older generation females was 1.7 times that of calves from younger generation females. They point out that when the cost of this intergenerational effect is combined with the known benefits conveyed to grandchildren by grandmothers, the numbers to do work out and it becomes clear that menopause is a wise biological investment for a long lived species. You can read more in The Economist article that I wrote on this here.

Podcast: Robobee

Bees are in big trouble. Their populations are declining rapidly all over the world and if they vanish entirely agriculture is going to suffer. The reason is down to pollination. Many plants depend upon bees to carry pollen from one plant to another. This allows the plants to sexually reproduce and is essential to maintaining genetic diversity. If bees perish, plant sexual reproduction will grind to a halt. For this reason, ecologists are working very hard at keeping bees around but, just in case they fail, engineers have their backs with drones that can pollinate plants in the absence of insects. You can listen to the full story on The Economist's science podcast Babbage here.

Toxin tracking

Chemotherapy drugs are a lot like cats, release them into space and you never really know where they are going to go. Even when the same drug is used against the same sort of cancer in two different patients its behaviour can be very different. The worst part about this is that medics often can only work out where a drug has gone by monitoring patient health. It would be better to know immediately whether a drug is accumulating where medics want it to and now a team is revealing that they have found a way to do this.

The researchers behind the new work developed a tactic for attaching labels made of radionucleotides to specific cancer drugs that are carried inside tiny capsules called liposomes. They then used positron emission tomography scans to monitor the movement of the drugs in mice with different sorts of cancers. 

With mice suffering from breast and ovarian cancer, the team were encouraged to find that the drugs accumulated in tumours and bone tissue at levels well above those in normal tissues. However, in some female mice belonging to a specific genetic strain the drugs concentrated in their uteruses where no cancer cells were present. This is useful information and will become doubly so when this technique starts getting used in people. You can read more in The Economist article that I wrote on this here.

Detecting speech disorders with computers

Last year a team revealed that psychological depression and post traumatic stress disorder pepper adult speech with telltale signs that computers can potentially detect. Now a new study conducted by a different lab is revealing the development of a computer system that can detect childhood speech and language disorders whilst they are still easily treatable in their initial stages. 

Language disorders in kids often go undetected until the age of five or six when when significant learning damage has already been done. The researchers behind the new work are aiming to resolve this problem with their new computer system which analyses audio recordings of kids' voices as they retell a story presented to them in their own words. You can read more in The Economist article that I wrote on this here.