Shark week, moon time, the crimson tide, a visit from Auntie Flo: whatever you call it menstruation is the roughly monthly interval during which the uterus sheds its lining. For the uterus owner, it is not generally a super fun time; cramping, bloating, headaches, and fatigue are just a few of the symptoms associated with “that time of the month.”
The symptom I want to focus on today, though, is hunger. Whether for chocolate, pizza, or any food really, an increased hunger is a commonly reported phenomenon during, or right before, menstruation. Although we know that periodic (get it?) changes in appetite can be influenced by fluctuations in hormones such as estrogen and progesterone, I became curious whether this increase in hunger also correlated with an actual increased need for energy from food. Just like our bodies produce the sensation of thirst when they require more hydration, maybe they produce the sensation of hunger during menstruation in part because of an increased caloric need.
When we think of dogs-with-jobs our minds tend to go straight to police, search and rescue, drug-sniffing and guide dogs. But therapy dogs are the unsung heroes of the working dog world! These four-legged therapists undergo detailed training to help comfort, support and encourage people suffering from a variety of mental health issues. They work in all kinds of conditions — from hospitals to group homes — to bring their special brand of assistance to those who need it most. Let’s take a closer look at how these four-legged heroes are helping humans.
A few weeks ago I finally had enough of the cold brew trend and decided to see what all the hype was about. I followed this recipe (because $5 at Starbucks is just too much for me), and was surprised to find cold brew wonderfully smooth, sweet and mild. I love coffee, and though I drink it with milk and sugar, I’ve never especially been bothered by the bitterness or acidity of traditionally brewed coffee. None the less, cold brew is quite amazing, and it left me wondering what the chemistry behind it was.
It turns out that hot water (about 93 ℃ in most drip coffee makers ) accelerates the extraction of molecules and chemicals that, once mixed with water, form the coffee we know and love. Once brewed, the coffee continues to react with air and water molecules. This is why coffee goes stale. Heat accelerates these reactions (as it does most), so coffee left on a burner, or in your car, all day goes staler more rapidly.
In cold brew, however, there is no heat to help extract these molecules and to cause the break down of others. The time the cold brew is left brewing allows the chemicals to be extracted from the coffee grounds much like the heat does, but you do get different amounts of different chemicals, leading to a different taste. Notably, many molecules that taste bitter are not extracted in large amounts in the absence of heat, which explains cold brew’s sweetness. You may have also seen cold brew being sold pre-packaged in stores, a possibility that is afforded to it due to the cold water not accelerating the ‘staling’ process.
So for once it seems like the hype was justified, though I’ll stick to making my cold brew at home.
On November 21st, 2016 a thunderstorm swept across Melbourne, Australia. It brought with it the usual flooded basements, wet shoes and ruined picnics, but it also brought a strange outbreak of asthma. Asthmatics and non-asthmatics alike suddenly found themselves unable to catch their breath, coughing and in extreme cases not being able to breathe at all. By the time the storm had passed, there was a 672% increase in respiratory-related presentations to emergency departments and a 992% increase in asthma-related admissions to hospital. The storm contributed to the death of at least 10 people.
So what was it about this thunderstorm that spurred a city-wide asthma attack? Experts aren’t certain, but the best guess is pollen. It seems that polled, mould and other allergens can get picked up into a storm, riding on wind currents, and carried into the clouds. Up in the sky, they make contact with water molecules, which causes these allergens to break apart into microscopic particles that can more readily enter human lungs and cause reactions. In the case of Melbourne, the allergen of importance seems to be from ryegrass. A grain of ryegrass pollen can be broken down into 700 starch granules, measuring 0.6 to 2.5 μm, which may then be inhaled into the deepest parts of the lungs, and cause an asthma attack or an allergic reaction.
As roughly 20% of the world is sensitive to grass or tree pollens, you can imagine that these storms are quite bothersome to many. Melbourne wasn’t the first case of casualties due to storm inflicted asthma, and it sadly will probably not be the last.
The idea that periods can synchronize was first investigated in a 1970’s paper by Martha McClintock, who examined the menstrual cycles of women living together in dorms. McClintock found that after 7 months of living together, the women’s periods had gone from an average of 6.5 days apart to 4.6 days apart, leading to the idea that proximity caused the periods of these women to synchronize due to some chemical signal.
However, studies since then have been largely unable to replicate these findings. McClintock’s results are now largely believed to have occurred by chance or poor experimental design, with many researchers calling menstrual synchrony a methodological artifact.
While it may appear that periods are synchronizing, it is important to remember that not everyone has a 28-day cycle, as some range from 21-35 days. This variability allows synchronicity to vary and periods to occur at the same, or different times.
I wouldn’t blame you for thinking something along the lines of “just like everyone else,” but I’m here to tell you otherwise.
Being a veterinarian is a lot like being a human doctor. Besides the fact that both professions practice medicine, albeit on different subjects, they both require top grades and many years of school. They usually necessitate one to go into debt, to work long hours, to have extreme empathy and to be on call for days at a time.
Given their similarities, we’d expect them to have similar mortality rates and causes of death, but that isn’t the case. Veterinarians are at an extremely elevated risk for suicide.
Are you double jointed? If not, you probably know someone who is, because this relatively common condition occurs in 10-25% of the population! Technically, the term for ‘having super flexible joints that made you popular on the playground as a kid’ Is hypermobility, and it’s characterized by having shallow joints and flexible ligaments or cartilage. In the vast majority of people, having hypermobile joints is not dangerous, except if they use them to scare other kids.
However, in a minority of hypermobile people, symptoms beyond just increased flexibility can develop, such as joint pain, increased rates of fractures or sprains, fatigue or an increased susceptibility to conditions like whiplash. In cases where symptoms like these do occur, the person is said to have Joint Hypermobility Syndrome. Another condition however can lead to symptoms almost indistinguishable from Joint Hypermobility Syndrome, something called Ehlers-Danlos Syndrome (EDS).
EDS is caused by a genetic mutation that causes defects in either the structure or processing of collagen (the main structural protein of our bodies, making up 25-35% of all proteins) or other proteins that interact with collagen in connective tissue. EDS affects roughly 1 in every 5000 people and can cause less serious effects like chronic pain and easy bruising, or more serious effects like osteoarthritis or aortic dissections (when blood pools between layers of the aortic wall). EDS exists in a few different forms (7 actually), with the hypermobility form affecting approximately 1 in every 10 000 people. This hypermobility form of EDS is functionally undifferentiable from Joint Hypermobility Syndrome. Both conditions have the same diagnosis criteria, and treatment recommendations, and not even a genetic test can identify which syndrome a patient has. Due to this conflation, most experts currently recommend thinking of Joint Hypermobility Syndrome and hypermobility EDS as 1 condition, until a way to distinguish them can be found.
Humans might not have hair as thick as chimpanzees covering their body, but our arm, leg and eyebrow hair all serves as reminders of our primate ancestry. So why don’t Homo sapiens have whiskers like other simians? To answer that, let me explain first what whiskers do, besides look adorable.
Whiskers are vibrissae, keratin filaments that grow out of different follicles than hair. Whisker follicles are much deeper than hair follicles and are surrounded by pockets of blood that amplify vibrations to better communicate information to the nerve cells beside the follicles. You may have noticed when looking at your cat that there are 2 kinds of whiskers, long and short. Long whiskers are macrovibrissae and can be moved voluntarily. Animals use these to sweep areas (called whisking) to navigate spaces and generally feel the world. Short whiskers are microvibrissae, and they cannot be moved voluntarily. These are used specifically for object recognition, whether it’s your rat’s favourite toy or your hand.
In general, animals use whiskers to help them ‘see’ the world, navigate it and identify features. Humans used to have whiskers too (about 800 000 years ago we lost the DNA for whiskers), but have now largely integrated the function performed by whiskers into their brains, specifically into their somatosensory cortex. The human brain devotes relatively huge portions of itself to sensing and processing touch.
Certain areas of the body, like fingertips, lips and genitals have much greater sensitivity to touch than other areas like the back or legs. A visual representation of this sensitivity to touch can be seen in the Cortical homunculus, or by performing a simple test: Have a friend use 2 pencils to touch your arm, while you close your eyes. Have them move the pencils closer and closer together. At a certain point, you will not be able to distinguish whether you are being touched by 1 or 2 pencils. Have the friend repeat this activity on your fingers, then your back. You’ll quickly notice that you have a much more sensitive sense of touch on your hands, feet and face. This test is called the 2 point discrimination test, and it’s often used to test patients for paralysis.
So we as humans may not have cute whiskers anymore (though our simian cousins still have microvibrissae), but rest assured we’re no worse off for this loss, just slightly more dependent on our brains.