22 January 2014

'The Life Sciences Podcast' by the University of Manchester

Hi all,

I'd like to draw your attention to a podcast that's produced by some of my friends from the University of Manchester. The podcasts have a similar agenda to my blog and aim to keep you updated with the latest news, research and interesting stories from the life sciences.

Podcasts are posted on the site fortnightly and include interviews with scientists from the university, which is one of the world's leading research institutions and employs lecturers that are at the forefront of their fields. The podcasts are a superb way to keep up to date with breakthroughs (and are extremely fun and interesting to listen to).

If you're interested, click here

20 January 2014

Ghost organs: the future of transplant medicine?

The human body is far from perfect, being at risk from numerous degenerative diseases that 'break' essential organs and lead to our deaths. Aging, disease and poor lifestyle choices are the obvious causes of such organ failure and our current level of science and technology is largely unable to cure such damage.

Organ transplants provide patients with the best hope of survival, in which the defective organ is replaced by a healthy one from a donor. Needless to say, such operations are dangerous and carry high risks of patients' dying during the operation, from the patient’s own body rejecting the new organ and secondary infections (caused by post-surgery immunosuppressant drugs).

Last year, 166 people in the UK went under the knife in heart transplant operations [source]. Needless to say such operations are dangerous and, despite recent advancement in aftercare treatments, 1 in 10 patients will die within the following year. Their body rejecting the new organ is the main cause of these deaths, which kills most patients within the first month from the surgery.

Yet despite the risks thousands of people are on transplant waiting lists all over the world, being desperate for the chance of getting a replacement organ to extend their lives. Improvements in operation procedures and aftercare have reduced the risk of dying during surgery in recent years, but rejection is still a major issue that patients must consider and is something that we are unable to prevent in every case.

Transplanted organs are rejected by leukocytes (white blood cells), which make up our body's natural immune system. All cells have proteins on their surface called antigens, which allow leukocytes to identify 'friendly' tissues. Foreign material has different antigens on its surface which, when detected by leukocytes, causes them to destroy the invading cells. This is usually beneficial and allows us to 'fight off' bacteria and viruses, but in organ transplants the donor actually needs the foreign material to live!

Anti-rejection drugs (which suppress our immune system), have had some success in preventing rejection, but they put the patient at risk of dying from common illnesses (such as colds and intestinal bugs) and aren't successful in all cases. The perfect solution to this problem would be to clone the patient’s organ so their body doesn't recognise it as 'foreign’ material' post-transplantation. But - thanks to all of the media’s unfounded nonsense and scare-mongering about stem cell research - our cloning technology is still a long way off being able to do this. We do have something similar in the pipeline though – ‘ghost’ organs.

This sounds ridiculous, right? But actually it’s not and a ghost organ is simply an organ that has been decellularized. Chemicals that are commonly found in detergents and shampoos are used to ‘wash away’ all of the organ’s cells until only a ‘scaffolding’ of extracellular connective proteins are left. Healthy cells are then taken from the patient and are grown over the connective proteins to repopulate the organ. Once this repopulation process is complete, the donor has a heart comprised of their own cells so rejection is EXTREMELY unlikely!

This is a ghost organ made from a decellularized pig's heart. All of the cardiac cells have been stripped away, leaving only the connective tissue.

If perfected, ghost organs have the potential to be transplant’s equivalent of cancer's 'magic bullet' and may save uncountable human lives in the future. But, despite having repopulated ghost organs with cells successfully, the technology still has its problems and scientists must find a way to make the cells functional if they are to used as replacement organs.

For example, the cells in ghost hearts beat discordantly as individuals, which means they would only pump half the fluid as a healthy heart around a host's body. Obviously, this means they aren't viable for transplants yet and scientists must devise a way to get them to pump in a propagated wave (as healthy heart cells do), before they will be of any medicinal use!

But prominent researchers in this field, such as Dr Doris Taylor from the University of Minnesota, are optimistic and predict that human trials will likely begin taking place in years rather than decades! Ghost lungs are proving to be particularly successful and research is progressing in using ghost organs to replace almost the entire human viscera!

5 January 2014

The truth about panthers

If you've ever sat down and watched a nature documentary, you've probably heard the term 'big cat' bandied about. But this is not a defined scientific term and there is often some confusion with what the big cat species actually are. Generally speaking, people asked this question usually reply with these four species: lions, tigers, jaguars and leopards. All of these species belong to the genus Panthera (which are renowned for their ability of roaring) and make up the largest, heaviest families of cat.

Depending on whether panthers are atypically coloured leopards or jaguars, an adult can be 7 to 8 feet in length and can weigh between 100 and 250 pounds. They are solitary animals and are examples of an apex predator, which is an animal that has no predators in nature.

Other people may give the same list as above, but also include pumas (cougars), cheetahs and the Eurasian lynx. This is fine as well since the term is ambiguous by nature and, as I've already mentioned, isn't scientifically defined. But what is incorrect is the inclusion of the panther. Obviously panthers are quite big and, upon spotting one, you would see a big, black cat. So why aren't they on the list? The answer is simple – panthers are not actually a species of cat.

Panthers are actually just leopards or jaguars (depending on whether they live in Asia or the Americas) that have an all-black coat. Their confusing and famous colouring—which is called melanism—is simply the result of their ‘dark-coding’ allele being defective. The allele is overactive and they produce so much of the black protein melanin in their fur that it masks the cat’s normal phenotypic colouring.

This is evident upon close inspection of a panther’s fur, where you will be able to see that it is not completely black. If you look very closely, you will be able to make out the normal colouring of a leopard or jaguar (although it will be very faint). Some have even gone as far as terming this phenomenon ‘ghost striping’!

Like all mutations, this defective allele was a fluke of nature. This means that it's rarer in jaguar and leopard populations than the normal protein (although the mutation is dominant in jaguars, which is fairly unusual), so most cats simply have their normal colouring. This is true as a basic rule, although research has shown that the all-black coat is actually selected for in certain environmental conditions so the panther phenotype is slightly more prevalent there than it is normally (although it never becomes more common than the normal phenotype). The main example of this is in areas that are very dark with densely packed foliage, where the panther’s darker colouring gives it an advantage in camouflage over the rest of its kin. 

Obviously their uniform colour means that panthers are visually distinctive from their normally coloured family members, but this is the only difference between them. All other aspects of panthers, such as their size, diet and behaviour are exactly the same as normal! This knowledge—along with the fact that panthers are genetically viable with their normally coloured kin (so can breed with them successfully)—means that they aren't their own distinct species!

3 January 2014

My New Year's revolution!

So that's it, 2013 is officially over and is now done and gone. I hope that you've all accomplished everything you wanted too last year and are now all set to have an even better 2014!

I'm certainly hoping I will and I have decided to start the new year by making the revolution to STOP neglecting this blog! Regrettably, I was rather busy last year and writing on here took a real hit. You'll be pleased to learn that I'm determined to correct this as of now and am aiming to publish two posts a month throughout 2014!

Be sure to keep checking this site regularly for a range of stuff I find interesting about this world we live in. I've already started writing my first one, which will be up fairly soon!