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!

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!

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!

Student budget eating guide

Okay, so strictly speaking this isn't actually a science post, but my sister is about to go to university and wanted some advice on eating cheaply for her friends and her. I really struggled for money when I was a student and have written up some of the tricks I used for saving money on my food bills. I thought that you might find this advice useful too, so I thought I'd post it here. 

Also, the point of this post is to help and advise people so please spread it to anyone you know who might find it useful - I know that plenty of people wouldn't look twice at a science blog, but could still benefit from this post!

Anyway, here it is!

The best way I found to budget for food was to plan all of my meals in advance. I used to do one big shop a week and made sure that I bought 21 meals of food in this trip (which is 7 breakfasts, 7 dinners and 7 teas). By doing this, I found I was able to set an affordable budget that I was able to stick to – the last thing you want to do is buy meals one or two at a time by shopping in supermarkets a few times a week. This makes it much harder to keep track of what you are actually spending because your bills are split into many different sessions and you end up spending way more. It’s also dangerous because the overall bill of each day is smaller than it is in one big shop, which used to trick me into thinking that I was spending less than I actually was.

A good trick that used to help me do this was to actually withdraw my allotted food budget in cash at the start of the week (I always made sure not to draw more out later). Mine was £15 a week, but I could have probably got this to less than £10 if I was really disciplined in what I bought (which is what most of budgeting actually comes down to). Anyway, I used withdraw £15 and then go and do my big shop. (When I was first getting into the habit of budgeting, I used to leave my card at home after withdrawing my cash out so I would have to put something back if I was over £15 – I literally couldn't pay for it)! If the overall bill was under £15, I used to put it in a pot for emergencies, snacks or let it slowly build up to £15 (so I wouldn't have to take money out on a week where I was really desperate).

Once you've done your big shop, try and stay out of supermarkets as much as you can. Only go in for things little things like milk and drinks.

Another piece of good advice is to ignore the special offers on things you don’t really need. These offers work by sucking you in on impulse buys and are always a sure way to blow your budget. You just end up with all these cakes (for example) that you don’t really want/need and most of them probably go off anyway because you can’t eat them fast enough. Secondly, if you actually spend the time to work out the maths in-store, they don’t even save you that much money. I found that the best way to avoid these deals was to make a list before you go shopping and the head straight to where the items are in the isles (and then straight to the tills without looking around too much). Saying that though, special offers can be a great way of saving money so look out for them on things you need or buy a lot (they crop up on healthcare products like toothpaste and shower gel all the time). 

Probably the hardest thing to budget for is alcohol. I never really got the hang of it to be honest, but I recommend that you don’t try to include it in your food budget and give it its own special one. Buy it in bulk as well – buy crates for cans/bottles and the biggest volumes of spirits you can afford – this is more expensive at the time, but works out way cheaper in the long run. Take advantage of the special offers as well! This might not be as applicable for you as it was for me (as I lived in the main student area of Manchester), but supermarkets used to slash prices of alcohol after holidays and exam periods so stock up then. I got 66 cans of Fosters for £20 once! Bear that in mind as it’s well worth keeping your eyes peeled!

Finally, don’t be conned into thinking that food from the big brands taste nicer than the supermarket own-brand ones – there’s usually very little difference in taste and the own-brand ones are cheaper and come in bigger packets. Avoid cheap, processed meat as much as possible, but it’s fine to buy everything else from cheaper brands. There’s not really any need to buy the very cheap own-brands either in most circumstances (as long as you are budgeting properly). I used to get away with buying Sainsbury’s Superior brands most of the time rather than Basics. For things like pasta and rice though, it doesn't really matter as Basics is just the same as Superior but in different packaging – it’s a ploy that supermarkets use all the time so don’t fall foul of it!

Anyway, that’s the best general advice I can give you. Budgeting for food is easier than you think – you've just got to sit down, work out what you can afford to spend each week and stick to it. Work out all your monthly outgoing costs – rent, bills and transport fares – and then how much you have coming in each month. The difference is your food, alcohol, going out and general shopping budget. Remember you can’t control your rent and bills, but you still have to pay them so make sure that this is a priority. Believe me when I say that it’s not fun being threatened with legal action and bailiffs by your landlord/utility providers!

I can also give you some good ideas for meals, which are cheap and will keep you pretty healthy – survived uni eating them anyway. (I was at uni a few years ago now and price of living has gone up, so things might not be quite as cheap as I say below. The principles of the pricing in the meals are the same though so stick to them and you should be fine).

Breakfast

Cereal’s the best thing – just buy a massive box of own-brand and you’ve got all of your breakfasts sorted for at least three weeks.

Crumpets and toast are good if you want a change.

• You can buy the cheapest own brands here because you’re heating them up. Think about it – bread gets dry and crisps over whether it’s cheap or expensive, which is what gives toast/crumpets their taste, so the brand’s quality really makes no difference at all

Dinner

Make your own sandwiches and bring them into uni/college.

• This seems like an obvious one, but for a few quid you can buy enough bread and fillings to last a week. If you buy a sandwich when you are out and about, it will be nearly £3 for just one meal
• I found the best sandwich filler to be cheese – a packet costs around £3 and lasted me for two or three weeks of sandwiches/teas (grating it rather than slicing it makes it last for much longer as well)

Also, look out for offers on things like Gingster’s Steak Slices as well – they are poor quality food, but are a good treat that can be used for dinner and tea.

Tea

Pasta – this can be ridiculously cheap if you do it right.

• Buy the cheapest own-brand pasta as you can find (as it all tastes the same), along with some pasta sauce and the biggest bag of frozen ‘mixed vegetables’ available
• For example, Sainsbury’s used to sell pasta for 7p a packet, sauces for £1 each and a big bag of mixed veg for £1
• Put the vegetables in first (as they always take longer to cook), and then add as much pasta as you want a bit later. Then just leave them to boil together for the time recommended for the pasta 
• You’ll need to play around with this a bit to get the timings right (so the veg and pasta are both ready to eat at the same time)
• Leaving the hob on, tip the pasta back into the pan and pour in as much sauce as you need (I went for half here and put the remainder in the fridge, where it will keep for a few days). Keep stirring for a few minutes – this is just to warm the sauce up really – and then you can eat it. The whole process takes about 15 – 20 minutes, so the meal is quick to make as well!

Pasta bake – this is a good meal when pasta bake sauce is on offer.

• Just buy a packet of the same pasta as above and follow the cooking instructions on the back of the jar
• You can buy different flavours that include meats etc, which really helps to bulk up the meal
• You want to cook all of the sauce at once and put loads of pasta in the baking tray. Once it’s cooked, you should have two or three meals worth of food here (depending on how much pasta you used), so keep what you don’t want in a sealed contained in the fridge for later
• This won’t last for too long, but I found that it was fine for about two days after cooking it. I wouldn't leave it any longer than this though, especially if you've cooked meat with it

Jacket potato – another really cheap meal here.

• Buy a packet of potatoes (Sainsbury’s used to sell 4 for £1) and the required number of fillers (i.e. Sainsbury’s sold cans of own-brand baked beans 15p each/tins of tuna for 35p each)
• Bake a potato (the easiest way to this is in a microwave, so just Google it if you don’t know how) and use a whole tin of the ‘filler’ to go with it – this fills you up way more than it sounds, it’s got almost no fat in it whatsoever (unless you go for tuna and mayo) and you get loads carbohydrates and protein (especially if you use tuna and mayo)

Burgers.

• Buy some frozen burgers (try not to go for the very cheap ones here), some buns and whatever else you want like cheese, salad and sauces
• Make your burgers and eat them with a few chips/a salad to bulk the meal up
• As with everything else, try to buy the biggest bag of frozen chips as you can
• You should be able to get two or three meals out of this for about £3 - £4

Spaghetti bolognaise – this might sound expensive, but it’s surprisingly cheap and gives your body all of the needed protein, carbohydrates and fat (you need some fat in your diet to be healthy, so never cut it out altogether).

• Buy fresh mincemeat (don’t buy the very cheapest stuff here), along with some sauce and the cheapest own-brand spaghetti you can find
• I used to buy around 320g of Sainsbury’s Superior mincemeat for around £3.50 (it changed slightly every week) and split it into thirds. I then put each third into a plastic sandwich bag, put all the bags in a sealable container and froze them – defrosting individual portions of meat as a needed them
• Bolognaise sauce is actually pretty expensive in supermarkets, despite it being almost exactly the same as pasta sauce. Unless you really want it or it’s on offer, I recommend that you just buy normal pasta sauce. I found that Sainsbury’s ‘chunky vegetable’ sauce worked the best for this meal. It was also £1 a jar, which gave me three meals worth of sauce.
• Using some sort of cooking oil (again, own-brands are fine for this), fry the mincemeat by referring to the cooking instructions on the label
• Be careful here if you’ve never fried meat before – common sense should tell you can get really ill from undercooking it. I suggest that you ask someone or Google it when you try this for the first time
• Towards the end of the meat’s cooking time, tip as much of the fat and oil away as you can (which makes the meal much healthier) and pour as much sauce as needed onto the meat. Stir it in and just leave it simmer for the remainder of the cooking time (stir it occasionally so the meat doesn’t burn onto the bottom of the saucepan)
• I used to pour about a third of the jar here because I split the split my mince into three portions – however you decide to do it, try to make sure that you have enough sauce to go with all of your mince for the week’s allowance
• Also, don’t pour the fat down the sink’s drain as this will block it after a while (the fat collects in the U-bend) – tip it into the bin instead

And that’s it really. This is the best advice and tips that I can give you – just use your brain and try remember these three rules:

PRE-PLAN 21 MEALS A WEEK

BUY EVERYTHING IN BULK

AVOID IMPULSE BUYS

Face off: the great white shark vs the killer whale

Our oceans are full of predators, ranging from tiny carnivorous fish to poisonous snakes; from poisonous snakes to electrocuting eels; from electrocuting eels to murderous dolphins. In short, predators are everywhere and none are more feared than the great white shark and the killer whale. Both of these animals are titans – huge animals that can hunt and kill almost anything they want to (and yes, humans are included). But which of these is the top predator? Which of them would best the other in a fight?

The great white shark, Carcharodon carcharias, is one of the most feared animals in the oceans. The sharks often hunt by taking advantage of their huge strength, ambushing the seals they hunt from underneath while they rest on the surface. Unfortunately, surfers resting on their boards can look very similar to seals from underwater, which is believed to be the main cause of great white shark attacks on humans.

I’m sure many of you are thinking that this would be the great white. And why not? Great whites have been known to kill humans and there is a huge ‘fear culture’ around sharks after Peter Benchley’s Jaws was televised in a film. You would be wrong, however, and there is a case that to show that it is in fact orcas that rule the oceans.

In the first instance, you have to remember that orcas are social and hunt in packs (which has actually earned them the nickname of ‘the wolves of the sea’). Obviously, this provides killer whales with a huge advantage over the solitary great white and orcas can bring down prey much larger than themselves. In fact, orcas have even been known to go after small female sperm whales (which are actually the largest predator alive), so picking off a lone great white shouldn't be too much of a problem for them!

Like humans and other primates, killer whales are extremely social and live most of their lives in tight-knit social groups of close family members. To prevent the inbreeding that this would inevitably lead to, male orcas usually leave their maternal pod once they sexually mature and actively seek another pod to live with for the rest of their adult lives.

Secondly, you have to consider the intelligence of killer whales, which are part of the same family of oceanic dolphins (Delphinidae). All of the members in this family are extremely resourceful and have been seen to use complex, highly sophisticated tactics while hunting their prey. In fact, killer whales have actually been observed practicing to hunt (click here for more information) and it is one such tactic that leaves little doubt that orcas are hierarchically above great whites.

As you may or may not already be aware, orcas have different cultures (in much the same way as humans do) and different pods in various locations around the world specialise in hunting certain animals. Common examples of their sources of prey include fish and water mammals, such as seals. But it is the pods that specialise in hunting sharks that are really relevant for this post. Such orcas have realised and taken advantage of two very simple aspects of shark anatomy:

• Firstly, most species of shark go into a hypnotic state of sleep called tonic immobility when they are turned upside down
• Secondly, sharks have to keep swimming in order to breathe and, as soon as they stop moving, water ceases flowing through their gills and they begin to suffocate

Since great white sharks have to keep swimming in order to breathe, they have developed a remarkable method of sleep where they rest each half of their brain separately. This allows the neurotransmitters in their brain to recover to normal levels after waking activity, while simultaneously allowing the shark to keep moving and remain alert for prey and danger.

By taking advantage of these two simple facts, orcas can kill sharks extremely easily and with very little risk of injury to themselves (i.e. the sharks can’t fight back). To do this, orcas take advantage of their extreme agility and ambush sharks from above. As they near the unassuming shark, they bite it just above their dorsal fin and use their strength and body weight to roll the shark upside down, meaning that it falls asleep and stops struggling. Then, it’s just a simple case of the killer whale holding its breath while it waits for the shark to suffocate and die!

This tactic is merciless and brutal, but it is extremely effective and scientists have actually seen killer whales using it on great whites off the coast of California! What is also interesting, other than orcas being able to kill great whites so easily that is, is that great whites (like many species of shark) release chemicals called ‘death signals’ into the water when they are killed. These signals drive off all other great whites for miles and, for many years, scientists were baffled by why the massive predator suddenly vanished from Californian waters. It was only when they realised that the exodus of great whites coincided with the seasonal arrival of a certain pod of orcas from Antarctica that they put two and two together and began to observe how the two predators interacted. Just imagine their surprise!