Mirka Loiselle/THE VARSITY

U of T develops small beating heart

Dr. Millica Radistic, a professor at U of T’s department of Chemical Engineering, has successfully grown beating heart tissue using electrical stimulation.

The heart is about the size of a dime and was developed using a type of human stem cell called pluripotent stem cells. These stem cells have the potential to differentiate into different cell types in the body, including heart cells, which Radistic has successfully grown into working, beating tissue.

With timed application of growth factors these undifferentiated stem cells are programmed to turn into premature cardiomyocytes, otherwise known as heart cells.

Although at this stage the heart cells are still not fully developed, Radistic explains that these immature cardiomyocytes are digested and placed in little wells in a specially designed bioreactor. Once the cells are in the bioreactor, electrical stimulation of increasing frequency is applied.

“We keep stimulating it at [a] faster and faster rate,” says Radistic adding that, “this is almost like a gym for the cell.”

The electrical stimulation procedure results in more mature heart cells. It is possible that these heart tissues will replace animal cells in pharmaceutical testing.

“When [pharmaceutical companies] have new drugs, they are only 75-90 per cent sure about the drug safety before they go into human trials,” Radistic explains. “We believe that arrays of human heart tissue could help in both safety testing and also in discovery.”

“We grow millimetre-scale tissues, something like the size of a quarter or dime, and then these little pieces of tissues could be used in future studies, translational studies.”

  Nyima Gyalmo

Don’t stress, your skin will thank you later!

Going to a competitive school like U of T causes students a lot of stress, which can be visible on their skin.

Previous research has made an association between skin conditions and stress. Due to a small sample size, however, these studies are limited.

Researchers at the Lewis Katz School of Medicine (LKSOM) at Temple University wanted to pursue the issue further, so they conducted a cross-sectional study during the fall of 2014. Five thousand undergraduates were surveyed to report their perceived psychological stress and any skin complaints. The final sample contained 422 students divided among three groups: low stress, moderate stress, and high stress.

Results showed that students who were under high stress on a regular basis suffered skin problems more often than students who were under low stress. These symptoms include pruritus (itchy skin); alopecia (hair loss); oily, waxy or flaky patches on the scalp; hyperhidrosis (troublesome sweating); scaly skin, onychophagia (nail biting), itchy rash on hands; and trichotillomania (hair pulling).

Dr. Gill Yosopovitch, the chair of the dermatology department at LKSOM, says, “Our findings highlight the need for health care/dermatology providers to ask these patients about their perceived levels of psychological stress. Disease flare or exacerbation while on treatment in the setting of increased stress may not necessarily reflect treatment failure.”

The results can be valuable to dermatologists who treat undergraduate patients, as it may help them to better diagnose and treat skin conditions.

— Jasmine Chopra

Does economic inequality mean more Uncle Scrooges?

Nobel Prize winning economist Joseph Stiglitz once said, “There is great divide in America. And we probably shouldn’t count on the rich to donate their wealth.”

A new study by researchers from U of T’s Rotman School of Management and Stanford University found that those with higher incomes are less generous than those with lower incomes when they live in places with high income inequality.

The results come from a survey of  around 1,500 people in the US playing the “dictator game;” participants were given raffle tickets which they could decide to donate. People earning more than $125,000 in US states with more income inequality were significantly less generous than similarly high-earning residents of states where there was less income equality. The generosity of people earning less than $15,000 did not vary.

A further experiment, where 700 people were given false information regarding the inequality in their home states, revealed similar correlations between perceived inequality and generosity amongst the rich.

The researchers think this arises because people in unequal societies may feel more entitled to their income or try to rationalize their position. They also believe that progressive taxation and other policies that equalize income could possibly foster more generosity among high earners.

— Sudipta Saha

Canada acquires first ‘dimetrodon’ dinosaur fossil

Scientists at U of T recently identified the first Canadian fossil to belong to the Dimetrodon family. They are creatures that, despite their dinosaur-like appearance, were more closely related to mammals than to reptiles.

Surprisingly, the fossil itself is not a new discovery; it was dug up in 1845 by a farmer on Prince Edward Island. Joseph Leidy of Philadelphia’s Academy of Natural Sciences believed the fossil was the jaw of a dinosaur and named the species Bathygnathus borealis, describing its “deep jaw” and northern origin.

The scientific community had long suspected Bathygnathus was not a dinosaur, but rather a member of the Dimetrodon family. The fossil’s status was not confirmed until Kirsten Brink, then a PhD candidate at UTM, realized an analysis of the teeth within the fossil could potentially identify it as a Dimetrodon. Brink’s team used a CT scanner at the Princess Margaret Hospital to take images of the interior of the fossil. After processing the images at Carleton University, they found that the fossil contained Dimetrodon’s distinct “steak-knife” teeth, allowing Brink to positively identify the fossil as a member of Dimetrodon.

As a result, Bathygnathus borealis has been renamed Dimetrodon borealis, merging two previously distinct groups and forming a distinctly Canadian contribution to paleontology and phylogenetics.

— Andrew Kidd

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