Posts Tagged ‘clinical trials’

Animal to Human Transplantation

// December 13th, 2009 // 3 Comments » // How Things Work, Recent Research

As I gazed out over the undulating ocean I could feel a twinge of phantom pain in my lost leg, it always twinges so when the beast is near. Perhaps some part of it’s spirit was not cleaved so sharply from my body, and it can sense its physical counterpart is close and yearns to be reunited again. Perhaps it hungers for revenge against the monster. Perhaps it is a prosthetic it desires, carved out perhaps from the fleshy appendages of the monster itself, a leg for a leg if you will. The beast today is nowhere to be seen, but still I stand and ruminate on such matters of animal to human transplantation.

Australia, my home port, decided on Thursday to lift their ban on animal to human transplantation clinical trials and join countries such as New Zealand and the USA. The ban was started five years ago due to concerns diseases could spread from animals to humans during transplant, but the evidence now shows that this is an unlikely outcome and the possible benefits (curing diabetes, an alternative to stem cells) outweigh the possible dangers.

Pig with Mask

Animal diseases can rarely enter humans, because we have different cells and physiology. A microbe which can happily infect a cat is stumped when it comes to infecting a human (where’s the tail? Where the hell am I?) and the further the animal gets from a human the less likely they are to cross-infect (worm microbes are unlikely to jump to humans.)

However there are some exceptions. The flu is a big one, owing to the fact that it has eight pieces of RNA that are packaged into a single virus particle, and if an animal (usually a pig or a bird) catches both human flu and pig/bird flu at the same time, and both kinds infect the same cell, there can be mistakes in packaging that creates a new strain of virus UNLIKE ANYTHING WE’VE SEEN BEFORE. It’s called an antigenic shift, and if the packaging creates something that is very good at infecting humans then we’re in trouble. Our immune system doesn’t like being confronted with weird things. Other exceptions include HIV which swapped from monkeys to humans, and Yersinia pestis which can infect rats and humans and caused the Black Plague.

Pandemic flu, HIV, the black plague… microbes may not jump animal to human often, but when they do the results can be severe. Perhaps this is why Jacqueline Dalziell had this to say: “The public, who had no say in this discussion whatsoever, will be the first to be directly affected if a new pandemic like AIDS … is introduced into Australia through the ban being lifted,” she said. “The whole of Australia is currently taking part in an experiment without their consent.”

On the other hand, perhaps it is because she is project co-ordinator for Animal Liberation and has other reasons against the decision. I disagree with the statement anyway, asking the general public what they think of the subject is a bit ridiculous, most people only know what they hear from the media and we all know what sensationalist bs that can be (if you don’t, check out Bad Science), an effort to educate people before the vote would probably be limited to a pissy brochure about the risks and benefits which most people wouldn’t bother reading anyway.

Not that I have a negative view on the public and science, I know you my fair readers are interested and educated on the science world, and I’m a science communicator at heart. But people, there’s a reason to do ENQUIRIES to make an INFORMED decision rather than tossing a question like this to the masses and saying “well this way if it goes bad, at least we can say they voted for it.” Whatever.

Patent Pirates

// September 7th, 2009 // Comments Off on Patent Pirates // Drugs, Science Communication

Medicines are made for two major reasons – to help people and to make money. Which one is more important?

On one hand, helping people is good. Curing the sick, easing suffering, what’s not to love? On the other hand, money is the incentive for new innovations. That’s just the way it works, you have to pay the big bucks to get the best people to work their hardest. It takes about $800 million gold pieces and ten years to bring a drug to market, and frequently a drug will fail somewhere along the way meaning you get zippo, zilch, zero in return.

Drug companies make their money back by patenting it so that no one else is allowed to reproduce it for 10 years. It’s like a protection of intellectual property with a decade expiry date. After that it’s a free-for-all, and at the pharmacy you can choose “The Generic” as a cheaper alternative to the brand name. Hopefully during their decade-long monopoly, the drug company that made the damn thing in the first place can make their money back and trillions more in profit.

This is where patent piracy comes in.

Pirate Pills

India has a tendency to ignore drug patents. This week Gilead, a US company responsible for anti-HIV drug Tenofovir, lost their case to prevent Indian companies making cheap versions on the sly. Very cheap versions. Instead of $5,700 a year, you pay just $800. Indian based company Cipla also makes a three-in-one anti-HIV drug called Triomune for only $87 a year, and a cheap version of Tamiflu.

Dodgy stuff, and these companies have spent millions on creating and testing these molecules. On the other hand, the price tag on a lot of these drugs rules them out to many in developing countries. I’m pretty sure most drug companies have a discount price when sold in Africa, but I don’t think they get this cheap. Think about how many people in Africa are HIV positive and don’t have much money, think about how many people die because of it, then consider that Africa is only 1% of the world’s medicine market.

Piracy perhaps, but this isn’t really a case of “take what you can, give nothing back.” I doubt companies like Cipla are making cheap versions of drug for purely altruistic reasons and I’m sure they make plenty of money by doing it, but is this robbing the rich to cure the poor?

Hat-tip to Ben Goldacre at Bad Science, read his detailed story with all the linky goodness here. Cheers Ben! Big Pharma and developing countries is massive subject, and this is just the tip of the iceberg.

The Science of Scurvy

// August 2nd, 2009 // Comments Off on The Science of Scurvy // How Things Work, Science at Home

It has been a shocker of a weekend, to be honest. Not completely crap (new shoes only $67, and SEXY! plus lots of time spent with SexyMan *grin*), but today has been a bit of a write-off as the ex came over to pick up his stuff resulting in a fair amount of awkwardness. As a result, Captain Skellett has extra ARRGH! today and would like to blog about scurvy, most piratey of all diseases.

Scurvy Man

Scurvy be a devil of a disease, afflicting in yon olden days mostly sailors and soldiers (and pirates obviously), which would be struck down with bleeding gums, sores, and eventually death. Often more people were lost to scurvy on the WAY to the battle, then at the actual battle itself.

Nowadays scurvy be a rare disease, at least in the more developed parts of the world, as we are well educated about the causes and conditions under which it begins. Namely – scurvy be caused by a deficiency of Vitamin C, and thus can be prevented and cured by a healthy amount of citrus fruits and other sources of C in your diet. Back in those olden days, though, they didn’t know WHAT caused it – plenty of things are different when you’re on a long sea voyage, salted and preserved foods, ocean air, damp environments and so on. It was hard to pinpoint what was actually causing the dreaded scurvy. What they needed was a controlled experiment.

Indeed, the FIRST CLINICAL TRIAL was performed by James Lind in 1747 as he looked for a cure for scurvy. On a voyage, as people began to succumb to scurvy he separated twelve of them who were at a similar stage of the disease, and tried six different treatments on them. The patients were put in one room to control their environment, and as well as standard rations, one group received cider, one sulfuric acid (tastes like burning), one vinegar, one seawater (!), one citrus fruit, and one barley water and a spicy paste.

The results were telling – the group that received citrus fruit showed tremendous improvement, and the group that had cider had a minor improvement. The rest showed no improvement at all. He published his results in A Treatise of the Scurvy. It was another 50 years before it was recognised as a prophylactic as well as a cure. Now people everywhere can so no to scurvy (behold the ubercute t-shirt below.)

Say no to scurvy

It was still a long time before they identified that it was a vitamin C deficiency that causes scurvy. Did you know that most animals (including S. cerevisiae, the yeast used to make beer and bread) can make their own C from glucose, and don’t need to have it in their diet? It’s really just monkeys, humans, bats, guinea pigs and some birds that have lost this ability – I guess that’s why you don’t often see a cat eating an orange. To make up for it, monkeys and humans can recycle ascorbic acid to some extent by reducing the oxidised (inactive) version. It is a cofactor for several enzymes, and plays a crucial role in the synthesis of collagen, which explains why a deficiency in it causes bleeding gums.

Reduced (active) version Ascorbic Acid <----> Dehydroascorbic Acid Oxidised (inactive) version

It is also a reducing agent, so it can mop up reactive oxygen species which form particularly in times of stress and injury. That’s why it’s good to eat an orange if you feel a cold coming on, and you should also eat one when you’ve had a busy week and an exhausting weekend. Matter of fact, methinks I’ll have one now. That or a strawberry daiquiri.






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