Lethal Adaptations In Nature: Tapeworms linking infection and cancer

Posted on November 9, 2015 by | Leave a comment

Parasites are some of the oldest and basic forms of life on the planet. Each and every species having honed their specific traits to leech and infest their host often through millions of years of natural selection. It’s a scary thought, to say the least. And one particular widespread parasitic species has recently been discovered to have made significant jump. Tapeworms.

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Tapeworm proglottids (50cm in length)
Author: Nathan Reading via Flickr Commons

It’s a certain parasite that I’m quite concerned about every time I pick up an egg sandwich at local gas station. Tapeworms often infest the digestive tract of animals and use their hosts are intermediary stages in their life cycle. In the case of humans, that infection is usually caused by consuming undercooked foods. The photo of a vomited tapeworm above was taken from a pregnant 26-year-old patient who had been living in East Africa. As you can see, they can grow immensely large in your intestine without any symptoms (one of the optimal traits of a model parasite).

If that wasn’t enough to make your skin crawl, a study published in 1999 found that up to 75 million people may carry the dwarf tapeworm with 25% of children affected in certain areas. When taking a much closer look with an electron microscope (image below), you can clearly see that tapeworms have an effective adaption on its head: suckers, muscular grooves, and hooks to latch onto your inner digestive system. Though rarely lethal, newly published research has uncovered a potentially deadly link between these worms and cancer.

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Hymenolepis microstoma (rodent tapeworm)
Author: Magdalena ZZ via Wikimedia Commons

A brief report was published this past week in the New England Journal of Medicine, detailing an unprecedented case of a tapeworm (or any parasite of that matter) transferring cancer cells into a human. The team of American researchers led by Dr. Atis Muehlenbachs from the Centers for Disease Control and Prevention claim it to be the first reported case of its kind. Easing public fears, it’s also been described as extremely unusual and rare.

NEJM_Issue-12

Source: The New England Journal of Medicine

The story begins in Columbia in 2013 when a 41-year-old man stumped local doctors of his deteriorating condition. He was ill, losing weight, and struggling with a prior HIV infection. Upon further examination, a CT scan of his lungs showed many tumorous growths which were made of cells not identified as human. That shocking revelation prompted them to contact scientists at the U.S. CDC.

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Figure 1 (A). Radiographic and Pathological Features of Malignant Hymenolepis nana.
(Muehlenbachs et al. 2015)
Source: The New England Journal of Medicine

The CDC center in Atlanta found the cells to be much smaller than human ones. Ten times smaller. Eventually, a genetic analysis found the strange cells had DNA from Hymenolepis nana (the dwarf tapeworm). The current theory is that the HIV patient’s compromised immune system and a mutation in the tapeworm caused this spread of cancerous cells from parasite to host.  For a more detailed explanation of the biological mechanisms involved, check out the helpful video below courtesy of the New England Journal of Medicine.

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It’s important to note that original patient died before he was correctly diagnosed. However, perhaps the results of this investigation may prove to be fruitful for others in the future as millions of people suffer from both tapeworms and HIV.

Tragedy aside, one has to admire how amazing this discovery is. For myself, I’m so impressed by the international collaboration of medical experts as well as the nature of the case. Even the language used in the original paper sounds very dramatic, “Invasion of human tissue by abnormal, proliferating, genetically altered tapeworm cells is a novel disease mechanism that links infection and cancer.”  (*I’ve underlined some phrases to emphasize their impact.)

It feels like something out of the TV show House MD: a medical mystery, bizarre clues, the elusive search, and the extraordinary resolution. It’s the kind of passion that I believe Muehlenbachs shares.

“We were amazed when we found this new type of disease – tapeworms growing inside a person, essentially getting cancer, that spread to the person, causing tumor…” – Dr. Atis Muehlenbachs of the U.S. CDC

Furthermore, I’m sure this case will spark a new field in medical research of cross-species oncology. I admit that this mutation may not be very beneficial to the tapeworm as it prematurely kills off its human host and may end up being a once-in-a-life phenomenon. Nonetheless, it’s a great example of how a parasite can dramatically change the relationship with its host and how we should approach treatment of unknown diseases.

By Paul Yi

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Esther Lo’s Green Rush in Canada

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Brains and games in 21st century – How do video games affect us?

Posted on November 9, 2015 by | 3 comments

There is a lot of debate regarding how video games influence our brains development and whether or not games are beneficial or damaging. Scientists have examined both sides and the question that needs to be answered is whether games are beneficial or they are transforming us into machines.

digital mindcredits: http://guardianlv.com/2013/08/researchers-develop-mind-control-using-the-internet-video/

Some studies show that prolonged exposure to video games has negative effect both on the body and the brain. Games decreases attention span, increase the risk of obesity and violent games decrease sensitivity towards aggression. The implications are troubling since decreased attention implies lower academic performance and obesity is a health risk factor. Furthermore it is shown that decreased sensitivity towards aggression not only makes us consider aggressive behavior acceptable but it also increases the chance that we will become aggressive.

aggressive gamers

credit to: http://yoursinglesourcefornews.com/ academics-debunk-theory-linking-violent-video-games-with-aggression/1379/

Another fact that must be considered is repetitive tasks in games. Because there are lots of games that become repetitive and have reward systems that encourage that behavior gamers are exposed to lose of creativity. Since repetitive tasks are better suited for a computer we could ask ourselves if our mind is encourage to become a basic processing unit.

However, there is another side of games which was investigated by researchers and the findings encourage people to become casual gamers. The benefits from games are as follow: better cooperation skills, adaptation to new challenges, fast reaction time and better attention to details.

brain-skills-games

credits: http://www.jklmgames.co.uk/how-games-can-train-the-brain

Besides the standard types of games we should also consider games that involve movement (e.g. some Nintendo Wii games) which are shown to motivate exercise. Those type of games should become encouraged in populations with increased risk of obesity, where the reward system should be tailor for the customers.

The tricky part of the games is the reward system which acts as a drug since it releases dopamine which is the hormone for excitement. Using this we can develop games that can stimulate people to learn and train. A study done on surgeons  showed it is possible to increase job performance via gaming. Here is a TED talk about games and how we can use them to construct a better world.

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Based on what we seen so far casual consumption of non-violent games have beneficial effects, however one must take extra care since crossing the line and becoming an addict can severely impact us.

Radu Nesiu

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Newly discovered hormone can possibly change the future of weight loss?

Posted on November 8, 2015 by | 2 comments

Obesity is a leading health problem in Canada and many other countries throughout the world, with it becoming one of the leading causes of death worldwide. However, what if someone who is clinically obese can decrease their body fat simply by taking a pill? Modern prescription drugs for weight loss do exist; however, they aren’t very effective and can have messy side effects! 

Obesity, Author: Tony Alter, Source: Flickr Commons

Well, recent scientific discoveries may have found the perfect candidate to serve as a replacement for the current prescription drugs available for treating clinical obesity. Irisin, a hormone produced by skeletal muscle cells during exercise is capable of burning fat tissue reserves when introduced into circulation. Irisin achieves this by converting white fat cells, which are the fat cells used to store fat in the human body, into brown fat cells, which are fat cells responsible for burning fat to produce heat. 

An article published in Nature showed that increased irisin levels in humans and mice causes more brown fat cell development, which lead to an increase in energy usage in the form of burning existing fat tissues. This increase in energy consumption occurred in a controlled environment, without any changes in the mice’s amount of physical movement or food intake, which can lead to induced weight loss in obese individuals (Bostrom et al.). 

Tension quickly rose due to researchers speculating if irisin actually exists in the human body, with studies criticizing the methodologies that Bostrom et al. used to detect irisin within humans. However, a recent article published in Cell Metabolism  by Bruce Spiegelman showed definitive proof that irisin does exist in the human body. Instead of using more traditional methodologies commonly used to detect hormones in the human body; Bruce Spiegelman and his colleagues used  a new method involving mass spectrometry to accurately detect and quantify the amount of irisin in participating human subjects (Spiegelman et al.).

Isn’t that great then? Shouldn’t pharmaceutical companies quickly adapt the hormone irisin and start producing a weight loss pill? However, I think the issue of time restricts any advancements in the pharmaceutical industry in actually producing such a pill. Since irisin has only been discovered in mice recently, and confirmation of irisin in humans was only published in August 2015. 

Diet Pills

Diet Pills, Author: joaneQEscobe, Source: Flicker Commons

As well, I would like to bring up a similar weight loss drug that was invented in 1933 that also showed the same promise as irisin. DNP, or 1,3 dinitrophenol was shown to increase metabolism rates by converting chemical energy into heat. Though the mechanisms that they occur aren’t identical, the end result of increased body metabolism and body temperature is observed for both DNP and irisin. DNP quickly became a wonder drug that took North America by storm; even now, DNP can be purchased online as a diet pill. However, tragic deaths have been associated with usage of DNP as a weight loss treatment, with terrible consequences of DNP overdosing including fatal hyperthermia (extreme body heat).

I feel that with something as promising as irisin being capable of helping obese individuals loose weight, the pharmaceuticals, FDA, and researchers have to take responsibility and caution in the future. Making sure that if irisin does become a prescription drug to treat morbid obesity, the tragedies associated with DNP will not occur again in the 21st century. 

Here’s a video on Scishow explaining current weight loss pills :

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By: Yu Chieh (Brian) Cheng

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Jelly-like Features of Disease-causing Proteins

Posted on November 2, 2015 by | Leave a comment

I remember when I was a kid (or even now), one of my all time favourite snack is strawberry flavoured Jell-O (or jelly). Not to mention, making it was so easy and so much fun, as the strawberry aroma would fill the kitchen.

C. elegans worm used in the study. Source: Wiki Commons

C. elegans worm used in the study. Source: Wiki Commons

Scientists at the University of Cambridge, led by Peter St George-Hyslop used nematode worm C. elegans as a model for amyloid lateral sclerosis (ALS) and frontotemporal dementia to study the physical properties of FUS, an essential RNA-binding protein in the body. The behaviour and physical properties of FUS can be closely compared to that of jelly. All RNA-binding proteins have two common domains: one for binding RNA and the other where the protein appears to be unfolded. It is at this unfolded region that the FUS undergo a process of reversible ‘phase transition’, which closely resembles the formation of jelly.

Comparison of ALS-affected and normal nerve cell. Source: Sarah Scoles

Comparison of ALS-affected and normal nerve cell. Source: Sarah Scoles

One common characteristic of all neurodegenerative disease is the irreversible accumulation of misfolded or mutated proteins aggregates in the brain, which as a result causes damage to the brain and disrupts communication between brain cells.  FUS is one of many types of RNA-binding proteins that is essential to the brain. It is essential in the regulation of protein synthesis, with functions in the nucleus and cytoplasm of a cell. However, the accumulation of mutated FUS and other associated proteins is also the underlying cause of the neurodegenerative diseases such as ALS and frontotemporal  dementia. Until recently, the significance and how FUS proteins affects the development of these neurodegenerative disease has been unclear.

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[Video courtesy of C.D. Net]

FUS starts out as soluble monomers (like the initial powered-form of jelly), and forms distinct localized accumulations. As it further condenses, a thick gel-like hydrogel structure is formed (like the formation of jelly after it cools in the fridge). This process can be reversible (like warming and cooling jelly repeatedly). Furthermore, during these transitions, RNA and proteins are continuously released from protein assemblies (like suspended fruits in the jelly as it is re-warmed and re-cooled).

The above processes are beneficial because it allows the cells to accumulate cellular machinery in a confined three-dimensional space (with no cell membrane required)  when needed to perform key tasks, but also disassemble when not needed. In addition, it is also faster and less-energy costly compared to the formation of a membrane-bound vesicle.

Although FUS is able to carry out vital cell processes by interchanging between different states, “this essential property also makes them vulnerable to forming more fixed structures if mutated, disrupting their normal function and causing disease” says Professor St George Hyslop. Mutation of FUS causes it to over-condense and become a thick fibrous gel, irreversibly trapping the essential RNA and proteins required for protein synthesis. It is the accumulation of misshaped FUS and other RNA-binding proteins that causes serious neurodegenerative diseases. However, further research and understanding of what are in these assemblies can bring us one step closer to curing ALS and other neurodegenerative diseases.

 

 

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On Wasps and Matricide

Posted on November 2, 2015 by | 2 comments

First, think of a wasp colony as a monarchy, where workers diligently provide for their queen.  Assume the queen is unsatisfactory, what would happen? A violent revolution perhaps?  This article on a study done by Kevin J. Loope explains how wasps are fully capable of committing matricide under the right conditions.

Matricide is not particularly uncommon in the insect world.  Many species such as crab spiders take part in matriphagy, or mother eating.  Wasps, on the other hand, depend on the queen to forage for food to feed their larvae.  Normally, fully grown workers are the ones that turn on their mother.

Source: Marjan Smeijsters on Flickr Commons

New wasp nests are formed in the spring after fertilized queens have finished hibernating.  Solitary queens construct the nest, lay eggs, and care for her larvae.  Only after the larvae have matured into workers, all of which are female, do the queen focus on reproduction and leave the other duties to her offspring.

An average wasp queen lays around 100 eggs each day.  Some workers are capable of laying eggs, but only for drones, or male wasps, and are discouraged by the queen through attacks or egg eating.   While in most cases wasps let their mother be responsible for passing on their genetic data, workers may get rid of the queen if being able to produce their own offspring outweighs the loss of new siblings.

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The queen’s mating practices are an important factor.  Queens normally only mate once or twice, but that does not imply an even distribution of full siblings.  In single-father colonies or colonies skewed to have many full siblings, workers are more closely related to their nephews than their brothers.  Loope noticed that because workers are willing to take care of closely related nephews, females will kill the queen to have the colony raise their young instead.  Wasps are believed to be capable of identifying its relatives.

Past research also reference low queen productivity or queens producing only males as reasons for matricide.  From this we can hypothesize that while wasps may work for the greater good on the colony, the queen is not necessarily vital to the continued welfare of the collective.  It puts a new light on what some would believe to be mindless workers.

Here is a basic video on the various stages of a yellow jacket wasp’s life:

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credit to ScienceOnline on Youtube

blog by Ivan Lan

 

 

 

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Effects of Sleep Deprivation

Posted on October 28, 2015 by | 8 comments

It doesn’t come as a surprise that a night without enough sleep can lead to a dazed morning. However there are more serious side effects to sleep deprivation than just drooping eyelids and yawns. There is no clear definition of exactly how little sleep is considered as sleep deprivation since each person needs different amounts of sleep. Rather, a person is considered sleep-deprived if they do not get enough sleep to feel awake and alert.

Still, research has shown that people can be both physically and psychologically damaged from sleep deprivation. In fact, it is unethical to purposefully deprive someone of sleep because the damage can be severe. The problems start on a minor scale, since the brain does not work very well when sleep-deprived. Some of the first impacts involve the ability to experience positive emotions. A sleep-deprived person may say they’re happy, but will have a neutral face, and they won’t recognize other people as happy either. The sleep-deprived brain may not be as capable of detecting positive emotions as well as a well-rested brain.

As well, as little as a single night of sleep deprivation can result in a phenomenon called “microsleeps”. During microsleeps, a person begins to fall into mini-snooze sessions which last about 30 seconds. The brain will go into a sleep state uncontrollably, and although people can force themselves awake, they will soon fall into another microsleep.

On a more major scale, losing sleep may cause delirium and even death. True delirium occurs when a person becomes completely disoriented. This often happens in patients who are hospitalized in intensive care units where lights and sounds continue all day and night, and doctors think loss of sleep is a major reason they develop bizarre behavior. Most seriously, researchers have found that no sleep can kill lab rats. In 2012, a Chinese man reportedly died from 11 days of sleep deprivation. Of course, it is not an easy venture since a person will most likely fall asleep before they die of sleep deprivation. Everything we know about sleep deprivation is harmful, but on a more positive note, most of these detrimental effects dissipate with enough sleep.

Here is a TED talk on why we sleep:

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post by Katherine

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