Just quickly - didn’t feel I could post fluff like this without a ‘proper’ post before it.
Thanks to all the new followers over the last couple of days, We’re now over double of what I was hoping to writing for when I set this up (not going to say numbers, in true tumblr terms it’s pitifully small).
But thanks again, and if anyone wants a particular subject in a new post, or has any thoughts, please ask away.
Venomous snakes are present in every part of the world, with hundreds of different proteins in each venom, with the sole purpose of immobilising and/or killing prey. I know what you’re thinking here:
‘God! What an amazing source of new drugs for heart disease!’
No? You aren’t? The rest of us all were, honest…
Why can we use venoms to cure rather than kill? It’s because of how they alter our bodies control systems.
We see Cobras causing paralysis by targeting our nervous system, the proteins in their venom blocking any signals from passing through the synapse.
We see loads of snakes mess with the cardiovascular system, as causing blood pressure to fall through the floor is generally a sure fire way to take out your prey. Some Asps and Mambas can do this.
Others, particularly Vipers, stop your blood from being able to clot, in a pretty roundabout way. Through activating all the clotting factors in your blood, they all get used up, and so you can’t clot when you need to. This is called a ‘consumption coagulaopathy’, and many die from either massive internal bleeding, or severe external bleeding.
How can we use these venoms for new medicines though?
Well, as Paracelsus says (well, said, a good 500 years ago):
Alle Ding’ sind Gift, und nichts ohn’ Gift; allein die Dosis macht, daß ein Ding kein Gift ist.
Roughly: ‘The dose makes the poison”
We take venoms, and use them in ways that give an effect we, as doctors, want.
(an american copperhead, whose venom has been used in cancer treatments - image from Brian Gatwicke, click on picture for original)
People always say to wear sunscreen because the UV rays could cause damage to your skin cells that could potentially cause cancer.
Most recently a singular type of skin cancer has been on the rise, Cutaneous Melanoma. A type of cancer that is difficult to treat and…
The biggest news is this bit
However, this interferon lets the tumors grow because they repress the immune system and the body can’t kill the damaged cells that are now multiplying.
The interferon mentioned is IFN Ɣ (that symbol’s read as ‘gamma’, The website reporting the paper has had some funky formatting issues)
Normally it causes inflammation, bringing in loads of other white blood cells, and they destroy the tumour before it gets too out of hand. The fact that it’s doing EXACTLY THE OPPOSITE of what it’s supposed to is pretty strange. (and a little exciting, in a very geeky way)
It’s not the only chemical in the immune system that does that, loads of cytokines have the ability to ‘turn themselves off’ when they get to too high levels.
Want to read more? Here’s the paper it’s all reported from:
“It [Female Genital Mutilation] is torture. It is inhuman. It is degrading treatment of women. It is against the Convention on the Elimination of All Forms of Discrimination against Women, the Convention on the Rights of the Child, and so many other conventions … There is no excuse for genital mutilation to live with us.”—
Ms Berhane Ras-Work, director of the Inter-African Committee on Traditional Practices Affecting the Health of Women and Children.
(This is far more global health than it is tropical medicine stuff, but still…)
This is NOT something you can chalk up to ‘cultural differences’. Maybe I’m being too much of an imperialist westerner but still, it’s assault in my mind.
The custom comprises a range of procedures involving partial or total removal of the external female genitals or other injury to the female genital organs for non-medical reasons. Not only does it confer no health benefits on girls and women but it can cause severe bleeding, urination problems, and lifelong consequences that include childbirth complications and deaths of newborns.
(If you can’t get access to the article, just message me and I’ll send you a copy)
Malaria Vaccine Trials – getting under fives to skip the hard learning
So the malaria vaccine mentioned last time (RTS) has been a long time coming (since around 1987) and no-one’s pretending it’s ‘here’ yet. But a paper released earlier this week suggests that it could have a pretty decent role in protecting children in malaria endemic areas.
Quick recap as to why that’s far bigger news than I just made out:
Malaria is responsible for around two million deaths a year, but these deaths are not evenly spread across age groups. In sub-saharan africa approximately 90-95% of all malaria deaths are children under the age of five.
Extremely tired, so will write about this properly tomorrow, BUT. Here’s evidence for a step further to a fully effective malaria vaccine (RTS,S/AS01E). Yup, that’s right, a malaria vaccine. Maybe not the holy grail of vaccines (thinking HIV here) but definitely impressive.
The efficacy doesn’t seem fantastic yet (45%ish), but then, there’d be a lot of herd immunity as well. Perhaps in mix with more vector control this would have a massive impact?
Yes, there are many problems with vaccinations for an endemic disease, even if the vaccine works more effectively than this does. I’ll chat about those tomorrow though. That and the challenges to creating a vaccine in the first place.
I’ve been brought up on a healthy diet of Radio 4 listening, and I’d recommend the programme ‘Case Notes’ to any budding medics out there.
Each week they cover a different topic in a half-hour programme - from Autism to Biomechanics
Note: Although part of the BBC World-service, it may not be available outside the UK.
As another Radio 4 geek, another good programme is More or Less. Useful for the stats side of things; when you hear something in the news and go ‘huh, that can’t be right’, they’re normally there to explain the many many ways someone’s been fiddling with the numbers. They’ve a podcast of episodes that I subscribe to…
Pharmacists who knowingly put lives at risk get off scot-free.
Yesterday it was announced that the Royal Pharmaceutical Council of Great Britain has dropped two cases, both against pharmacies that were recommending homeopathic ‘treatments’ to prevent malaria.
This wasn’t alongside recommending seeing a doctor or travel clinic before heading abroad. The advice of a few magic sugar pills was all that was given to a reporter, who had said they were heading to a malaria endemic zone for research.
Pharmacies have a role in protecting and advising the public on health care. They aren’t just a drug shop; they have an legal and moral obligation to make sure people are getting the medicines they require.
What occurred here was an abuse of their reputation as a source of medical information. Many don’t know the ideologies behind alternative medicines, and will accept a pharmacist’s word as the truth. By selling homeopathic ‘medication’ for a deadly condition, they were reckless and showed ignorance (or apathy) to the potential consequences.
Snake Bites (Post 1 of 2) - Global Issues and Health
Why should we care about Snake Bites? Most of us are sitting at home safe, well removed from any risk.
But whilst they may not be a danger to you personally, you’re still scared of snakes right?
I know I am. That fear’s been bred into us. Those without it couldn’t pass on their ‘SnakeConfidence’ genes, due to the problems associated with becoming lunch.
It’s not just the tropics that are affected; the ‘Tropics’ are the areas 23.5 degrees either side of the equator, but you find venomous snakes in the ares 50 degrees either side of the equator in the western hemisphere, and 30 degrees either side in the eastern.
Whilst an unnecessary fear for many of us, it’s an ever present risk for many around the globe. Yet it’s ignored by the medical community to a large extent. Like so many tropical diseases, the patients don’t have political sway on the level required to get the protection they need.
“We either have a major public health problem or a significant theological event: … More than 10 percent of teens who said they were abstinent also tested positive for a sexually transmitted disease”—
Article from Mike @ http://bit.ly/hBUZoc
(The values given in the article don’t seem to add up to 10% … I think really it’s 10% of the people who had STI’s also said they were abstinent (118 of the 964 who had STI’s).
But still; when you’ve got 60 teenagers who say they’ve ‘never ever ever ever had sex, not even a little bit’, who somehow have STI’s… you’ve got a problem with abstinence focused sex education. Yes that is a biased view on my part; a bias in preferring people to not catch preventable diseases.)
“But as for you, unlucky Laevus, your blood, congealed by a serpent of the Nile, choked your heart; you evinced no sign that the bite was painful, but in sudden darkness embraced death and went down to join the ghosts of your comrades.”—
Lucanus MA. Bellum civile (civil war). Book IX. http://www. thelatinlibrary.com/lucan/lucan9.shtml
- Chosen by David Warrell to introduce his Seminar on Snake Bite: ’Warrell, D. a Snake bite. The Lancet375, 77-88(2010).’
- Chosen by me to emphasise how much I’ll be relying on this seminar for my ‘intro to snake bites’ post coming up. David Warrell writes in an incredibly gripping manner, I’d really recommend reading his paper.
Antigens; or, what the immune system can see and fight.
Every post so far has talked of immune cells looking at whole microbes or cell fragments.
This isn’t really what happens. Your immune cells don’t see something like mycoplasma tuberculosis (which causes TB) as a whole organism; instead immune cells see separate, smaller, things called ‘antigens’.
Causative agent of TB, mycoplasma tuberculosis. Seen under electron micrograph (accessed from http://www.textbookofbacteriology.net/tuberculosis.html on 02-Jan-2011)
So to prevent us going on about ‘things’ much longer, what are antigens?
Antigens are molecules that the immune system can react to, and produce antibodies against. Really they’re any molecule an antibody could bind to. They’re antibody generating molecules.
Löffler’s Syndrome is a benign and self-limiting condition in which an allergic infiltration of eosinophils is seen in the lungs. This allergic reaction is most often due to drugs, such as sulfonamides, or infection with a fungus or parasite, including Ascaris lumbricoides (the giant roundworm of…
Eosinophilic Pneumonia… Maybe I’ll go over the parasite side soon? Only if I read up on it and promise not to balls it up this time…
Only a couple of posts in, and already I’ve ballsed up.
NK Cells are innate cells! Don’t know how I let that slip past me!
NK cells are of the lymphoid heritage, the same as B Cells and T Cells. However, they aren’t considered adaptive cells.
Many many thanks to http://svetlanasikorska.tumblr.com/ for pointing out my schoolboy error.
In the flow chart I’ve got in the tl;dr post; imagine I put Lymphocyte heritage instead of adaptive, and Myeloid heritage instead of innate. Then what is there would be correct (yup, it would be right if different)
Oh well! Posts will no longer be post without careful scrutiny, or whilst tired. Obviously as I thought I was on the basics I wouldn’t mess up… foolish…
p.s. We think of adaptive as adaptive as it has memory. NK cells have been recently shown to have memory. R Paust, S. et al. Critical role for the chemokine receptor CXCR6 in NK cell-mediated antigen-specific memory of haptens and viruses. Nature Immunol. 24Oct 2010 (doi:10.1038/ni1953)
Phagocytosis: Eat them alive and wash them down with Chlorine.
Phagocytosis goes on all over the body, all the time. When cells die and need to be removed, they’re often mopped up through this.
It happens much more though, in times of infection and inflammation.
Phagocytes have a simple approach to infection; take cells in and destroy them with as many chemical and enyzymatic processes as possible. Not so far away from dumping what you want to get rid of in a bucket and pouring all the bleach you can find on it.
>Can tell the difference between self and non-self (what’s ‘you’ and what’s everything else)
>Can tell which non-self components are dangerous (which things floating around in your intestine are cornflakes, and which are the cholera that came along for the ride)
>Removes (or at least attempts to remove) anything that it deems dangerous.
(EDIT: In the chart below, NK Cells should come under the innate heading. It’s wrong due to an absentminded mistake of mine. NK cells come from the same cells as B and T cells; they’re of the lymphoid heritage. Rather than the myeloid heritage that the rest of the innate cells come from. However, they are still considered innate rather than adaptive.)
Think of the post below as a reference, from now on posts will be shorter and a bit less text heavy. It’ll also be more detailed. (Shorter and more detailed? = Distilled Science…)
Oh! and there’ll be bloody loads of pictures too, not just mind-maps…
Cells in the Immune System - who they are and what they get up to... (EDITED)
How do infections take over a person? How do they cause entire countries to collapse? How do they spread across the world? Perhaps the more important question would be, why don’t they do that all the time?
Why do we find HIV killing millions when the cold gets far less impressive figures? Why do we find that one strain of flu causes mass panic when we live relatively comfortably with so many others?
The obvious reason is this; we have defense systems. These systems are separate in many ways, but they act together and come under a collective term, the immune system.
The immune system:
Can tell the difference between self and non-self (what’s ‘you’ and what’s everything else)
Can tell which non-self components are dangerous (which things floating around in your intestine are cornflakes, and which are the cholera that came along for the ride)
Removes (or at least attempts to remove) anything that it deems dangerous.
By describing the immune system and it’s tactics; we can understand how infections attempt to find weak points in the system, or how they use their own strengths to take hold in our bodies. Firstly, we should describe what the immune system is, before we can describe what it does.
So, what’s going to get looked at over the next little while? (I did enough of my own work today so I get to think about this!) I thought, to avoid being a one post and gone kinda affair, it’d help if I had a plan.
I want to start basic, that those who’ve not had an intro to immunology will be able to follow this all the way through. We’re going to cover wide areas of science, but with very few assumptions as to what people already know. So sorry if you’ve already got a reasonable grasp of this all, but this can just reinforce your knowledge; and there’ll be decent examples later on which may be new for you.
Above were some rough ideas put together quickly. As you could guess, the first ‘proper’ post will be an intro to immunology in general, and why it matters.
In fact, I’m going to stop procrastinating, and go and write it. Got to start at some point yeah?
Yes, I realise it’s pretty daft that I keep using the plural, the idea that there’s a ‘we’ to go over these ideas together isn’t true. But just in case…
My personal reasons for writing are in the post below, but why would you care about those? Content’s what matters.
Well the content will be looking at; medicine, parasitology, microbiology, virology, global health, and global politics through a certain lens.
The posts should allow anyone to understand these subjects above with only the tiniest amount of prior knowledge. Hopefully I’ll explain these topics in such a way that enthusiastic school kids should grasp; and those with greater understanding shouldn’t find them too basic.
So that’s why this blog exists, now why this title in particular? Well it’s partly as I had to think of one the second I chose to register, but it does highlight the subject.
Human bodies are constantly under attack, sometimes just from other bodies, but I’m thinking of a more zoomed in level. We have, over several million years, developed our immune system. This system of self defence protects us against intruders of all forms; who attack in ways I hope to describe in later posts. As quite a complicated and convoluted system; it can fail. Hopefully I’ll describe instances of that as well.
So in ‘Everything Versus Host’, I really do mean everything. We’ll cover viruses, bacteria, and parasites. We’ll also look at more weird situations, like what goes on with snake bites. There’ll also be a bit of host versus host, with autoimmunity in all its forms.
With these subjects we’ll start at a relatively basic point, but build it up to where we’ll push at the levels of current research.
and of course, when lazy, we’ll just link to other interesting articles.
This won’t be a updating more than once a week, if it does it’ll mean I’m procrastinating a bit too much and someone should get me back to my own revision. Over the next few days I’ll post my first ideas for topics (obviously, we’ve a lot of basics to start with).