Thursday 11 October 2012

Popping Hippos

As part of our wildlife course, we had a few interactive afternoon sessions where we got into groups and worked through a scenario. While that is generally misery-inducing, between the long hours and the forced group work, it turned out to be more fun than advertised thanks to our charismatic professor.

Our scenario was several dead hippos around a lake in Africa. We had to answer questions about what we would do to investigate, what tests we wanted, and what we would tell to local farmers or public health officials.

Do a post-mortem, we all thought, duh. 

Long story short, turns out we all caught anthrax. It's the ONE time that you don't want to do a PM, because once they get exposed to the air, they start forming spores. That's bad.

It was an interesting session academically, because there were a lot of questions about what you would do. How do you dispose of the carcasses? What's the danger to surrounding farms? (I believe we decided to tell everyone to vaccinate). In this scenario, there were a lot of poachers in the area who would eat the hippos and pose a massive public health risk, and the discussion on how to deal with that was fascinating. However, the real joy of the lab came from the reporter roleplay. You see, each group had to elect one spokesperson to talk to the media (played by the prof). They also had to wait outside so they couldn't hear what anyone before them got asked. My god, it was hilarious.

The prof did everything in his power to make my classmates squirm. He'd hone in on the slightest slip up of wording or hint that something was amiss. He grilled them. Plus, there was a great amount of hilarity from trying to get my classmates to explain the medical terminology they kept using. 

The main takeaway message was, surprisingly for all of us, do not lie to the public. Don't try to "prevent panic" or whatever, just give them the facts. There is a danger, and they need to know the steps to take to protect themselves and their livelihoods. 

That, and don't pop dead hippos.

Sunday 7 October 2012

Worst Day Ever

So today, we had two tests. One in pharmacology and one in pathology. By name, and even by content, those classes are pretty cool. In reality, they both are run by the two suckiest professors we have this year. I will probably write more on that front later.

They were both computer-based tests. The first one was supposed to be a two hour test on therapeutics. This consisted of 15 multiple choice questions, where you're given a clinical scenario, and literally have ten to fifteen options of drug combinations and there is only one correct answer. At the beginning of the year, the prof casually mentioned that the average mark for this particular test has historically been around 45%.

If the test wasn't stupid enough by itself, the prof was mysteriously missing at the beginning of the test. Our class rep called the undergrad office and tried to get in touch with him, but no one could. We sat there, spinning in our computer chairs, for an entire hour before he turned up. He didn't have any excuse, as far as I can tell he just forgot.

Did he move the test date? Give us extra time at the end? No, we had to complete our two hour test in one hour, and if it was really a problem he would give us some allowance at the end.

That was in the morning.

In the evening (yes, evening... most of our tests this year have been at 5 or 6pm) we had pathology. This was only an hour test, and the prof did show up on time. We were all ready to go, and he bids us begin, and right at that moment the university website goes down so no one can access the test.

There was a fair bit of fumbling, calling the undergrad office, calling IT, and again we had to wait an hour before we were able to take our test. I just wanted to go home and have supper!

Getting home was never such a relief.

Saturday 6 October 2012

Dog Hearts

Unlike people, heart attacks are very rare in dogs. Come to think of it, they are rare in all domestic animals.

Interestingly about dogs, they do get high cholesterol commonly. This is because a lot of dogs have hypothyroidism, and it causes high cholesterol (along with several other diseases). However, it doesn't tend to do anything to their coronary vessels and they are just fine.

Thursday 4 October 2012

A Bit About Pathology

In third year we have a double semester paper on pathology. It starts out as general path, where we learn basics of pathological processes, such as what's going on when there's inflammation or necrosis, and the rest of the year we go system by system learning about the common things that go wrong. You wouldn't believe the things that happen in the body!

Here are some of the ones I thought were interesting, I'll pick one from a few different systems:

Cardiovascular System - Patent Ductus Arteriosus
A fetus doesn't use its lungs, so its whole circulation is set up differently. It gets everything it needs from the placenta, and the lungs just stay uninflated and all the blood bypasses them. At birth, when the neonate takes its first breath and inflates the lungs, all the blood rushes to them and the bypasses shut off. There's a number of congenital diseases where those fetal shunts don't close properly.

For instance, there's a channel called the ductus arteriosus which, in the fetus, allows blood that would have gone to the lungs just go straight into the aorta instead and off to the rest of the body. Sometimes it doesn't close in the newborn. The interesting thing is that now, there's space in the lungs to fill, so rather than blood hopping into the aorta, it flows preferentially back out of the aorta and to the lungs (how much blood depends on how big the hole is). So you get blood that circulates uselessly between the heart and the lungs without ever going to the body.



Endocrine System - Pituitary Cyst
Honestly, the endocrine system is really cool, and I could put down any one of the diseases we learned about and be really excited, but they also all require long-winded explanations of what the hormones do and why you see the pathology that you do. So I thought I would show you a picture of a dog with a pituitary cyst, causing a lack of pituitary hormones including growth hormones (a pituitary dwarf). These dogs are littermates:



Gastrointestinal System - Rumen Acidosis
If you feed a cow too much grain, you can end up with this terrible domino effect of consequences. If they aren't used to eating grain and get a whole bunch at once, it screws up the microbes in the flora, and they start fermenting all the carbohydrate to produce acid. The lowered pH is called acidosis, and causes inflammation in the rumen wall, mucking up absorption of nutrients. This inflammation makes the wall weak and necrotic, so bacteria and fungi have a party, even making it into the blood.

Blood from the GI tract goes to the liver for processing, so the bacteria hitch a ride and hop out, causing liver abscesses. This causes clots to form in the big veins heading out of the liver back to the heart. The next place the blood goes is the lungs, so the clots can break off and float out there, and then get stuck in the lungs. This causes an aneurysm (outpouching of the blood vessel) which eventually pops and all the blood flows out into the airways. 

The cow proceeds to die a very dramatic and rapid death with blood pouring profusely from its nostrils. All because it ate a bunch of grain a while back.

Genital System - Teratomas
If you think about it, cells in the ovary are about as undifferentiated as you can get: eggs go on to create a new individual and divide into cells that form every tissue in the body. So if one of them goes out of control, it's not like a skin cell that does skin things or a liver cell that does liver things; its an embryo cell that does embryo things. So these tumours have all kinds of crazy things in them, like fully formed teeth, hairs, and glands.

Liver - Hepatogenous Photosensitivity
For animals that eat plants, like cows, microbes in the GI tract break down all the chlorophyll they ingest, and this forms a compound called phylloerythrin that gets absorbed into the blood. It's the liver's job to take care of that stuff and get rid of it. If the liver gets munted, the phylloerythrin builds up.

You know how chlorophyll absorbs sunlight? This breakdown product floating around in the blood also reacts to sunlight. Once it makes it to the skin, it absorbs and releases energy from the sun, basically making the animal get bad sunburns. 

Lymphohaemopoeitic System - Hemangiosarcoma
The spleen is involved in monitoring and storing blood, and in dogs it's the main predilection site for a type of cancer called a hemangiosarcoma. This is basically cancer of the blood vessels, and I think it's really interesting because, since it's the cells that make up the vessel walls, when they proliferate they try to form new blood vessels. Since they're cancer cells, they really suck at it, so the result is a bunch of shitty weak random vessels that are prone to rupture. Unfortunately this type of cancer is very deadly (it's most common in dogs).

Skeletal Muscle - Myotonia
This is actually a terrible and tragic genetic disease in people, horses, dogs, and cats, but for some reason goats have a perfectly harmless version.




Monday 1 October 2012

Brachycephalic Airway Syndrome


Brachycephalic Airway Syndrome



Are you one of the people that think flat faced dogs are cute? Well, maybe they are, but you shouldn't be supporting them. They are kind of a joke among veterinarians--every time a lecturer mentions them it's always with a snicker. You see, they can't really breathe. And it's entirely on purpose. It's a genetic disease that is entirely preventable, but people think it's cute, so people keep breeding for it.

They live their entire lives snorting and snuffling because they have tissue falling down the back of their throat. When we anaesthetise dogs we put a tube down their trachea, and most dogs rather resent it when they're waking up. These dogs actually don't mind because it's probably the first time in their lives they can actually breathe.

Brachycephalic airway syndrome is a combination of stenotic (narrow) nostrils and an excessively long soft palate. That is the tissue that separates your nose from your mouth near the back. The theory is that as we breed for shorter faces, the genes for bones respond and the skull gets short, but the soft tissue doesn't respond as quickly, so that's relatively too big. What's even worse is that bulldogs commonly have hypoplastic (underdeveloped) tracheas, so not only is there a bunch of tissue to try and breathe around, they are also breathing through a straw.

So remember, if you buy one of these dogs, you are supporting the breeding of dogs with a genetic disease. You may think its cute but your dog will live its entire life without being able to breathe properly. I don't think it's very fair to the animal.

Not Unlike the Parasitology Prof

Meet Thelazia callipaeda. This nematode feeds on tears.