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The curious tale of the cancer ‘parasite’ that sailed the seas

The curious tale of the cancer ‘parasite’ that sailed the seas

‘Canine transmissible venereal tumour’ is a cancer that spreads between dogs through the transfer of living cancer cells, primarily during mating. The disease usually manifests as genital tumours in both male and female domestic dogs. It first arose in an individual dog, but survived beyond the death of the original dog by spreading to new dogs. The cancer is now found in dog populations worldwide, and is the oldest and most prolific cancer lineage known in nature.

One of the most remarkable aspects of these tumours is that their cells are those of the original dog in which the cancer arose, and not the carrier dog. The only differences between cells in the modern dogs’ tumours and cells in the original tumour are those that have arisen over time either through spontaneous changes in the cells’ DNA or through changes caused by carcinogens.

An international team of researchers, led by scientists at the Transmissible Cancer Group at the University of Cambridge, has compared differences in tumours taken from 546 dogs worldwide to try to understand how the disease arose and how it managed to spread around the world. Their results are published today in Science.

“This tumour has spread to almost every continent, evolving as it spreads,” says Adrian Baez-Ortega, a PhD student in the Transmissible Cancer Group, part of Cambridge’s Department of Veterinary Medicine. “Changes to its DNA tell a story of where it has been and when, almost like a historical travel journal.”

Using the data, they created a phylogenetic tree – a type of family tree of the different mutations in the tumours. This allowed them to estimate that the cancer first arose between 4,000 and 8,500 years ago, most likely in Asia or Europe. All of the modern tumours can be traced back to a common ancestor around 1,900 years ago.

The researchers say that the cancer first spread from Europe to the Americas around 500 years ago, when European settlers first arrived at the continent by sea. Almost all the tumours found today in North, Central and South America descend from this single introduction event.

From the Americas, the disease spread further, to Africa and back into the Indian subcontinent – almost all places that were, at the time, European colonies. For example, the cancer is seen in Reunion, but this was where European travellers would stop off on the way to India. All of this evidence suggests that the tumour was spread by sea-faring dogs, transported through maritime activities.

While the findings related to the historical spread of the disease are interesting, it is the tumour’s evolution that particularly excites the researchers.

Recent developments in cancer biology have enabled scientists to look at the mutations in tumour DNA and identify unique signatures left by carcinogens. This allows them to see, for example, the damage that ultraviolet (UV) light causes.

Using these techniques, the researchers identified signatures for five different biological processes that have damaged the canine tumour over its history. Four of these, including exposure to UV light, are known processes already linked to human cancers. However, one of them – termed ‘Signature A’ – has a very distinctive mutational signature, different to any seen previously: it caused mutations only in the tumour’s distant past, several thousand years ago, and has never been seen since.

“This is really exciting – we’ve never seen anything like the pattern caused by this carcinogen before,” says Dr Elizabeth Murchison, who leads the Transmissible Cancer Group at the University of Cambridge.

“It looks like the tumour was exposed to something thousands of years ago that caused changes to its DNA for some length of time and then disappeared. It’s a mystery what the carcinogen could be. Perhaps it was something present in the environment where the cancer first arose.”

Another intriguing discovery related to how the tumours evolve. There are two main types of selection in evolutionary theory – positive and negative. Positive selection is where mutations that provide an organism with a particular advantage are more likely to be passed down generations; negative selection is where mutations that are likely to have a deleterious effect are less likely to be passed on. Such selection tends to occur by way of sexual reproduction.

When the researchers analysed the tumours, they found no evidence of either positive or negative selection. This implies that the tumour will be accumulating more and more potentially damaging mutations over time, making it less and less fit to its environment.

Baez-Ortega explains: “Normally, we see selection pressures acting on an organism’s evolution. These canine tumours are foreign bodies, so one would expect to see a battle between them and the dog’s immune system, leading to only the strongest tumours successfully being transmitted. This doesn’t seem to be happening here.

“This cancer ‘parasite’ has proved remarkably successful at surviving over thousands of years, yet is steadily deteriorating. It suggests that its days may be numbered – but it’s likely to be tens of thousands of years before it disappears.”

Materials provided by University of Cambridge

Study demonstrates stress reduction benefits from petting dogs, cats

Study demonstrates stress reduction benefits from petting dogs, cats

College is stressful. Students have classes, papers, and exams. But they also often have work, bills to pay, and so many other pressures common in modern life.

Many universities have instituted “Pet your stress away” programs, where students can come in and interact with cats and/or dogs to help alleviate some of the strain.

Scientists at Washington State University have recently demonstrated that, in addition to improving students’ moods, these programs can actually get “under the skin” and have stress-relieving physiological benefits.

“Just 10 minutes can have a significant impact,” said Patricia Pendry, an associate professor in WSU’s Department of Human Development. “Students in our study that interacted with cats and dogs had a significant reduction in cortisol, a major stress hormone.”

Pendry published these findings with WSU graduate student Jaymie Vandagriff last month in AERA Open, an open access journal published by the American Educational Research Association.

This is the first study that has demonstrated reductions in students’ cortisol levels during a real-life intervention rather than in a laboratory setting.

The study involved 249 college students randomly divided into four groups. The first group received hands-on interaction in small groups with cats and dogs for 10 minutes. They could pet, play with, and generally hang out with the animals as they wanted.

To compare effects of different exposures to animals, the second group observed other people petting animals while they waited in line for their turn. The third group watched a slideshow of the same animals available during the intervention, while the fourth group was “waitlisted”. Those students waited for their turn quietly for 10 minutes without their phones, reading materials, or other stimuli, but were told they would experience animal interaction soon.

Several salivary cortisol samples were collected from each participant, starting in the morning when they woke up. Once all the data was crunched from the various samples, the students who interacted directly with the pets showed significantly less cortisol in their saliva after the interaction. These results were found even while considering that some students may have had very high or low levels to begin with.

“We already knew that students enjoy interacting with animals, and that it helps them experience more positive emotions,” Pendry said. “What we wanted to learn was whether this exposure would help students reduce their stress in a less subjective way. And it did, which is exciting because the reduction of stress hormones may, over time, have significant benefits for physical and mental health.”

Now Pendry and her team are continuing this work by examining the impact of a four-week-long animal-assisted stress prevention program. Preliminary results are very positive, with a follow-up study showing that the findings of the recently published work hold up. They hope to publish the final results of that work in the near future.

Journal: https://journals.sagepub.com/doi/10.1177/2332858419852592

Materials provided by Washington State University

pet kitten companion

Study finds most of the pet owners are not aware of pet blood donation schemes

A new survey of pet owners which has been published in Vet Record finds that the majority of dog and cat owners are not aware of several blood donation schemes and blood banks for pets.

A large number of pet owners in this survey said that they were ready to allow their pets for donating blood. Researchers say that this suggests an increase in awareness can help in an increase of donors similar to human blood donation.

The need for animal blood has been increasing in veterinary practice. The percentage of pets donating blood is not clearly known but is supposed to be quite small. However, the demand for blood is more than the supply which is available.

Researchers from the Royal Veterinary College investigated awareness of pet owners for small animal blood donation. They also surveyed about their attitude and motivation of their pet being a blood donor. 158 dog and cat owners, over the age of 18 were surveyed for a period of 10 days. They were asked to fill an anonymous questionnaire regarding awareness of pet blood donation, motivations and concerns about their pet being a blood donor and whether they would be happy if their pet was fit to donate blood.

110 out of 158 were not aware that pets could donate blood, 118 were not aware that pet blood banks were there. 140 owners stated that they would allow their pets to donate blood if found suitable, 18 stated they would not. There was no major difference between the percentage of male and female owners who were willing that their pets donated blood. However, owners aged 71 or more and those who worked full time were less likely for letting their pets donate blood.

The most common motivation for pet blood donation was beneficence, the desire to help others. The next was the necessity of service, which refers to a recognition that blood products are needed and reciprocity, hoping helping others would make blood products available for their own pets.

Researchers have pointed out that this is a survey involving a very small sample size, only one clinic. As a result of this, the numbers may not match for a larger population. Although this is a good starting point in understanding the awareness of the general people about pet blood donation. Researchers conclude that recruitment of donors can be increased by increasing awareness among the pet owners. However, using animals for blood donation involves greater complexity and not all pets are suitable to participate in the process. Potential donors should be checked thoroughly by a vet before donating blood.

boston dynamics spotmini

Latest video released by Boston Dynamics shows its robot dogs pulling a truck

Do you know the quantity of sports robots required to construct a big truck?  Well, just 10! Apparently, ten canine-inspired machines linked and well connected to sled dogs like box truck, pulling it across the parking lot of Boston Dynamics with nearly one-degree uphill slope as shown by them in their video clip titled “Mush, Spot Mush!” posted on YouTube . Although during demonstration there was a driver behind the wheels in order to prevent accidents from happening, the vehicle itself was all neutral.

Boston Dynamics is an American robotics and engineering company which was started in 1992 by Marc Raibert, originally as a M.I.T spinoff. It is currently owned by the Japanese conglomerate group, SoftBank. It is quite popular for the humanoid robot, Atlas and BigDog, a quadruped robot which was meant for the United States military funded by DARPA.

It built the all-electric SpotMini , which is basically a quadruped robot that weighs approximately 66 pounds. It has only 17 joints and is equipped with a robotic arm which has a 5 degree-of-freedom and extends like a crane from its head. The machine has the capacity to run for up to 90 minutes, which definitely depends on the kind of work it does in that period, however it needs to be noted that the battery life is indeed shorter than an hour-and-a-half when it is hauling trucks SpotMinis are equipped with amazing three- dimensional vision cameras, as well as a suite of sensors in order to make it capable of navigation and mobile manipulation. The robotics company- Boston Dynamics said that it is the least noise producing machine it has ever produced, which now is almost out for sale as it comes out on the production line, being available for a variety of appliances.

Since these SpotMinis can carry insanely heavy payloads up to thirty one pounds, they have an arm that is potentially made to handle objects and carry them up and down the stairs. This makes these SpotMinis useful for warehouses and search and rescue missions in near future. Therefore, we can definitely conclude that Boston Dynamics is true to its slogan of changing our ideas regarding what robots can do!

We are not yet aware of what these robots would look exactly like or how much spot power will they be able to carry but the strength and rigidity definitely sets a benchmark in the robotics industry and challenges the newer generation of robots yet to come!