We're discussing human dissection in this week's Naked Scientists. Chris visits the dissection room to find out how trainee doctors benefit from dissecting real bodies, and why many medical schools are increasingly turning to alternatives. We're joined by physician and film maker Paul Trotman, who followed the lives, and beyond, of three donors to explore the reasons why people choose to donate their bodies, and the impact the process had on the student's lives. In Naked Engineering, we find out how a design that copies the body's own structure and movements can make better artificial limbs. Plus, how womens' tears can manipulate mens' moods, the perfect melody to send shivers up your spine and the headphones which can cancel out the sound of the dentist's drill.
In this episode
01:54 - IVF study could lead to prediction test
IVF study could lead to prediction test
More than 10 per cent of couples worldwide are infertile, and some of them turn to in vitro fertilisation or IVF, in the hope of having a baby. But it can be a difficult and heartbreaking process for many couples and there's no guarantee of success, although thousands of IVF babies are born healthy and happy every year.
But now a new study from researchers based in Glasgow and Bristol, published in the journal PloS Medicine, could lead to a more accurate test to predict how likely a couple are to succeed with the procedure.
The researchers, Scott Nelson and Debbie Lawlor, looked at the outcomes of every single IVF cycle in the UK between 2003 and 2007 - a staggering total of more than 144,000 cycles. Then they looked at a range of factors, including the age of the mother, how long the couple had been infertile for, previous IVF attempts, whether the mother's own eggs or donor eggs were used, and the particular techniques used, then correlated that with whether the IVF was successful, and whether there were any problems with the babies, such as being born prematurely or particularly small.
They put all the data into a computer and used it to build a prediction programme that could estimate the chances of a couple successfully making an IVF baby. The new model seems to be more accurate than previous IVF prediction models, as it's newer and takes more factors into account. But the model is only based on looking at IVF cycles that have already happened, so the programme needs to be tested in a forward-looking study.
The scientists hope to gather more data over the coming years from couples going through the IVF procedure, and the researchers are now working on making the programme available online and even as a smartphone app to help them test it. At the moment it will only be suitable for couples who have had their infertility investigated, but if it holds up, it could be a useful predictor to help couples decide whether they want to go with through IVF, and some of the possible risks they may face.
04:24 - Tears manipulate men's moods
Tears manipulate men's moods
Tears are traditionally judged to be a visual display of emotion, and humans, it's claimed, are the only species to shed them. But now scientists in Israel have found that they can also carry chemical messages to alter the moods of others close by, an observation which fits with earlier studies showing that the composition of emotionally-shed tears differs significantly from the composition of tears produced in response to eye irritation.
The new discovery, published in Science, was made by Edith Wolfson Medical Centre researcher Shani Gelstein and her colleagues. They showed two female volunteers some tear-jerking film footage and collected the watery results as they ran down the womens' cheeks. In a separate experiment they also collected saline solution dribbled down the same womens' cheeks to control for any odours that might be entering the tears from the skin.
These tear samples were presented in a blind fashion to the nostrils of 24 male volunteers who were asked to rate the sexual attractiveness of a series of female subjects shown in a collection of photographs. The photographs were viewed twice, once while the subject was smelling the saline control and again during exposure to the emotional tears. The researchers also measured the mens' testosterone levels during the study as an indicator of arousal.
Seventeen of the volunteers rated the same female faces as significantly less attractive when they viewed them whilst sniffing the tears compared with the saline. The subjects also had lower testosterone levels following tear exposure, and brain scans also showed a drop in neuronal activity in brain regions linked to mood when subjects sniffed the tears.
This suggests that, contrary to the prevailing view that tears are merely an outward display of emotion, in fact it appears that they also contain covert chemical signals that convey mood-altering messages to male recipients. The team point out that there is ample opportunity for such signals to pass from a teary-person to a recipient. "We hug a crying loved one, often placing our nose near teary cheeks, typically generating a pronounced nasal ihalation as we embrace."
However, the identity of the chemicals responsible for these effects remains a mystery, as does whether mens' or childrens' tears are capable of similar emotional chemicals manipulation...
07:23 - Chills of Musical Pleasure
Chills of Musical Pleasure
with Valorie Salimpoor, McGill University
Kat - Now I am sure that all of us have a certain piece of music that causes chills to run up our spines. Music so good, it elicits a genuine physical reaction. Now, researchers at Montreal Neurological Institute and Hospital have been exploring the brain basis of this experience, and to tell us more, we're joined by McGill University's Valorie Salimpoor. Hi, Valorie.
Valorie - Hi. How are you?
Kat - Great! Now tell us a little bit about the background to this. So what were you trying to find out with these experiments?
Valorie - Well, we know that music has been around for a very long time. We know that it's been around throughout history and in every single culture. Evidence for this goes as far back as history has been recorded and we know that things that usually stick around for long periods of time are usually behaviours that are biologically adaptive, or necessary for survival. But we are still somewhat unclear on how exactly music fits into this. So, what we do know is that music makes us feel really good and in fact, the euphoric feelings produced by music have often been described as similar to the rush of very powerful drugs like cocaine, for example. Interestingly, drugs like cocaine actually exert their effects on the dopamine reward circuit in the brain. And the reason why this is relevant is because the system in the brain is actually a phylogenetically ancient system and it has evolved to reinforce highly adaptive behaviours such as eating and sex for example. So when dopamine is released, these behaviours are strongly reinforced.
Kat - So it's kind of the bit of the brain, the pleasure centre of the brain.
Valorie - Exactly.
Kat - So how did you test whether this pleasure centre is linked to listening to music?
Valorie - Well we wanted to see if music is actually linked into the system and this is a hypothesis that's been around for a while. So, a few researchers have attempted to examine this. People have found, with their colleagues, that when you're listening to pleasurable music, there are some hemodynamic changes in the regions of the brain that are normally involved in dopamine or take reward. But the problem with that is, up until now, we didn't know if the neurotransmitter dopamine was actually involved. So we used a procedure called PET. This is Positron Emission Tomography and this uses radio ligands to determine how much dopamine is actually released and where. So people came in and they brought in their own self selected music that was intensely pleasurable for them and when they listened to it inside of the scanner, we actually found that they released dopamine. And this is sort of a big deal because the system is a very potent reinforcer and it actually, by definition, underlies our motivation and our desire to seek a reward.
Kat - So they're basically getting a natural high from listening to these tunes.
Valorie - That's exactly it, yes. Except that there are no severe consequences like there would be with drugs for example.
Kat - But one question I have. I mean, music is such a powerful thing in our culture and how do you know that these people don't just, "Oh, I love this piece of Debussy because it was played at my wedding." How do you separate whether it's just a nice memory or whether it's actually the music?
Valorie - That's actually an excellent question because music has such tight links with our memory systems that it's really, really hard to separate out the two and music is often used to sort of stimulate these pleasurable memories. So, the way that we tried to rule that out in our experiment is by doing extensive pilot testing where we asked people, is this in any way associated with a specific episodic memory in your life, for example, as you mentioned, your wedding or a summer in your life, or graduation, or some other happy time that they've had. If that were the case, then we didn't use those participants or those particular stimuli in our experiments because we had to try to rule it out. Having said that, this is something that can happen unconsciously. People wouldn't necessarily be aware of the fact that they do have some sort of a memory associated with this piece of music. So, in our next experiments, we'll be using new music that people have never heard before and try to see if we can replicate these findings with something that they can't have any previous memories associated with.
Kat - So what is it in music that makes us have this emotional experience? Is there any information about - is it a specific tune or chord sequences?
Valorie - Well it seems to be somewhat different for different people which is really what's fascinating about it because it seems to be very much a cognitive reward. It's almost as if our experience of pleasure to it is also is dependent on how we're following the tone sequences that we hear. An example of this is that if you hear a single tone, that's not really pleasurable for you, but if you hear a series of these single tones over time, that can become some of the most pleasurable and intense experiences that humans have ever reported. So, how exactly does this happen? David Heron for example has a book called Sweet Anticipation and he explains this very nicely where we develop a sense of anticipation to where these notes are going to go, and then our expectations can either be confirmed or we may be surprised but either way, it seems like composers sort of know this and they try to manipulate our emotional arousal with the way that they're sequencing these tones. This is probably why our appreciation of music is partly cortical or intellectual, or cognitive if you will.
Our results actually provide very nice evidence to support this hypothesis because we found that right before we combined our PET procedure with fMRI so we can get some temporal information on what's happening in the brain as well. We found that right before this peak emotional response which we measured by chills for example in our study, participants were actually showing dopamine release in different regions of the reinforcement circuit that has very strong connections with the frontal cortex. Now, the frontal cortex of the brain is a part that's highly developed in humans and it's basically what separates us from lower order primates and it houses complex thinking. So, what we see here is evidence of this complex or abstract appreciation of an aesthetic stimulus which in this case is music, is also tapping into the same dopaminergic system that reinforces the most fundamentally rewarding and biologically adapted behaviours such as food and sex. The same system also produces the same intense euphoric feelings of addictive drugs, such as cocaine.
Kat - Wow! That's absolutely fascinating and as a musician, I hope you find out what the key is, to making everyone love your music. That is Valerie Salimpoor from McGill University in Canada and you can find more about that story - it's published online in the journal Nature Neuroscience this week.
13:32 - Dental-drill cancelling headphones
Dental-drill cancelling headphones
For many, just the distant sound of a dental drill is enough to elicit a cold sweat, let alone having to endure it first hand during a filling. But now a new, noise-cancelling device developed by a London-based research team could help to take some of the pain out of the experience.
Inventor Brian Millar, from King's College Dental Institute, was initialy inspired to develop the new gadget by the efforts of the car-maker Lotus, who were working on a way to improve passenger comfort by using a sonic-cancellation system to remove unpleasant road noise yet leave passengers able to hear important sounds like emergency sirens or horns.
The new prototype device works similarly, cancelling out the high-frequency sounds of the dental drill whilst leaving the lower pitches - such as speech - untouched. Even better, it's designed to be compatible with the average personal MP3 player. So a patient could simply plug the device into the headphone socket of their player, then plug their own headphones into the device and then carry on listening to their own music - or even the Naked Scientists podcast - with the drill sounds being subtracted around them.
The noise cancelling effect works by listening selectively to the incoming sound of the drill and then producing a soundwave in the headphones which is the mirror image of the drill noise, suppressing the sound.
Brian Millar is now looking for external investment to take the invention to market. "The beauty of this gadget is that it would be fairly cost effective for dentists to buy, and any patient with an MP3 player would benefit from it, at no extra cost. What we need now is an investor to develop the product further, to enable us to bring this device to as many dental surgeries as possible, and help people whose fear of visiting the dentist stops them from seeking the oral healthcare they need."
16:27 - Going topless harms hearing
Going topless harms hearing
Despite their suave appeal, convertible cars could have to carry a health warning owing to the threat they pose to the occupant's hearing.
Writing in the Journal of Laryngology and Otology, St Louis University researcher Anthony Mikulec and his colleagues measured the noise levels experienced by passengers travelling in five different makes of cabriolet, including a Porsche 911, at a range of speeds and with the roofs both on and off.
Guidelines relating to levels of noise exposure suggest that sustained exposure to sounds louder than 85 decibels (dB) is likely to permanently damage hearing, probably by metabolically stressing the hair cells in the inner ear where soundwaves are converted into brainwaves.
In the study, with the roof off and moving at about 55 miles per hour (88 km/h), three of the five cars were already exposing passengers to sound intensities close to this threshold. When the speed was increased to over 70 miles per hour (120 km/h), sound levels at or above 85 dB were recorded in all of the cars, and in one model sustained levels of nearly 100 dB were measured. This effect was negated when the roof was in place, with passengers experiencing sound levels of about 75 dB, well below the limit considered safe.
These results suggest that long car journeys in open-topped vehicles are likely to expose passengers to sustained noise of 100 dB - the equivalent of holding a running chainsaw - particularly when the traffic is heavy as this increases incidental noise, or if the car radio or music is played since this will be turned up even louder to compensate for the ambient sounds.
According to Dr Mikulec, "In light of the results of this study, we are recommending that drivers be advised to drive with the top closed when travelling for extended periods of time at speeds exceeing 85.3 km/h".
So, topless round town then, but not elsewhere...
18:57 - Planet Earth Online - Variation in Viper Venom
Planet Earth Online - Variation in Viper Venom
with Wolfgang Wuster & Axel Barlow, Bangor University
Kat - Scientists at Bangor University in North Wales have found that different species of deadly viper snakes, tailor their venom to a particular prey. Knowing about these venom variations can help save lives as anti-venoms developed for one type of snake may not actually work for another. We sent Planet Earth podcast presenter Richard Hollingham to meet researcher Wolfgang Wuster who introduced him to the beautiful but deadly Saw Scaled Viper.
Wolfgang - The saw-scaled vipers do make a noise. When they're annoyed, they curl themselves up into a figure of eight or pretzel-like position and rub their body coils against each other and that produces a hissing or rubbing sound which is really quite characteristic.
Richard - I don't want to put my microphone too close to this, given that - whoah! That's quite frisky!
Wolfgang - Don't worry, that's nothing.
Richard - Now you're manoeuvring the snake within the aquarium here and you're using very long tongs to do this.
So that noise was the scales rubbing against each other.
Wolfgang - Yes. It's their trademark defensive behaviour. If they get upset, which happens quite easily, then they coil themselves up into this kind of pretzel-like figure and rub the scales against each other while inflating themselves with air, and you get this slightly hollow sounding hiss. The hypothesis is that this reduces their water expenditure which is what they would have if they hissed by breathing in and out like most snakes do.
Richard - This latest research has been conducted by Axel Barlow. He's found that the type of venom these vipers produce is adapted to the prey they eat.
Axel - In these snakes, some species feed on vertebrate prey like mammals and lizards, which is quite typical food for snakes, whereas different species eat quite unusual prey. Scorpions or centipedes. We found that the variation in venom composition is down to these differences in prey, so the species that eat scorpions and centipedes have a venom that's specifically adapted to feeding on that type of prey.
Richard - How did you do this research, other than carefully?
Axel - First, we looked at the diet composition of these snakes because often, real solid ecological data on snakes, such as what they actually feed on the wild is quite scarce. So we have to dissect hundreds of preserved museum specimens and that allowed us to demonstrate clearly that there was variation in the types of prey consumed. We then reconstructed the molecular phylogeny of the snake.
Richard - So really, you're putting together an evolutionary tree of the relationship between the different species, different variations in the snakes.
Axel - Yeah, that's it exactly and by having this evolutionary tree, that can form a framework for us to test our hypotheses. So through establishing the variation in diet, we could then test the toxicity of venoms to a natural prey item, which in this case, we chose a scorpion. By mapping the data of venom toxicity and diet onto the illusionary tree, we showed that changes in diet in the evolution or history of these snakes have been accompanied by an increase in venom toxicity to scorpions.
Richard - Wolfgang, in terms of evolution, why do you think this is?
Wolfgang - Venom is expensive stuff. It costs the snakes a lot of energy to replenish their venom reserves after they've bitten the prey item. So, for snakes that have more or less specialised diets, it makes an awful lot of sense to produce a venom that is of high toxicity to that prey so that they would only need the small amount to actually kill it.
Richard - Are there implications of this research in terms of treating snake bites?
Wolfgang - In the long term, we would hope so. Variation in venom composition is a ubiquitous phenomenon in snakes, and it's of great relevance for the treatment of bites. So this snake that's sitting behind Perspex here is a West African oscillated saw-scaled viper, the one in the cage underneath is Pakistani saw-scaled viper. Now if you were bitten by oscillated saw scaled viper and you've got a specific anti-venom for that, you would have every chance of recovering and walking away from it. If you were to be given an anti-venom against the Pakistani saw-scaled viper, you would have a 20% chance of dying. And sadly, that's actually happening nowadays because African countries with access to fewer and fewer anti-venoms are now buying anti-venom in from countries like India and Pakistan, and it turns out, they don't work. So many people are dying needlessly as a result of that. What our research does is it starts to look at why we have this amount of variation in venom composition, and we're taking this further, and we're looking at the genetic mechanisms of that. So hopefully in the long term, it may allow us to predict which snakes are likely to have different venoms and which different venoms we may have to include in an anti-venom when we design one for a particular area. So in the long term, we would hope that this would have a beneficial impact.
Kat - That was Wolfgang Wuster and Axel Barlow from Bangor University's venomous snake facility, ending that report from hopefully still alive, Richard Hollingham.
24:21 - In the emotional tears experiment, did the subjects know what they were smelling?
In the emotional tears experiment, did the subjects know what they were smelling?
In the paper it says:
"24 men first sniffed a jar containing a compound which was either fresh tears or saline which was collected from the donor women."
And then later on they said:
"To keep them smelling the substance during the study, the compounds were deposited onto a pad, pasted onto the subject's upper lip, directly under his nostrils." So, the subjects were blind to what they're actually smelling. They didn't know it was tears. They just knew that they were being asked to smell something. Read more about this experiment, including a link to the original paper here.
25:00 - In the Dissection Room
In the Dissection Room
with Theo Welch, George Marsden, Chris Constant, Cambridge University
Chris - For thousands of years, people have been studying and documenting human anatomy. In these days, we do it to turn out well-trained physicians and surgeons. Students traditionally use bodies donated for dissections as well as prosections which are expertly prepared specimens that reveal the important structures they need to know about. But increasingly, medical schools are abandoning the dissection approach to teaching anatomy. So, I went along to one place that still does it this way - that's Cambridge University - to find out what their students think of the process.
Theo - Now we have some lovely arteries showing here. This is the common carotid and this is going to open into the external carotid which is here and the internal carotid which is going to go up into the skull and supply the brain. And the external carotid....
Chris - There are over 600 different muscles, 428 named nerves, and 206 bones in the average adult human, and a medical student needs to know the names of all of them.
Theo - We've got a nice prosection here of the side of the face with the skin removed and some of the muscles, and now, you can see a gland here. You know what that is?
Students - Parotid gland.
Theo - Good and coming out of the front of the parotid are a number of little structures. Do you know what they are?
Students - Facial nerve?
Theo - The facial nerve, yes. Now do you know any of the branches of the facial nerve?
Student - Zygomatic.
Chris - But building up a mental picture of how all these different structures in the body fit together and in three dimensions is very difficult. Traditionally, trainee doctors have done it by dissection, cutting up human bodies usually under the trained eye of an expert anatomist like Theo Welch whom we've just heard. So, what do present day students make of the process..?
Abigail - I'm Abigail Lucas from Gonville and Caius College, Cambridge, first year medical student. I think it's really good because you can actually put it into perspective. I look in the textbooks, but it's not the same as actually seeing it. It'd be really difficult to do it and get it properly with just textbooks. It's really beneficial to actually to get to see it and then you can actually visualise much better in 3D.
Lahiru - My name is Lahiru [Handunnepthi] and I'm from Hughes Hall. What do I think of dissections? I think it's fantastic. It's a really good way to learn anatomy. I mean, you get to see the structures that you don't normally see in textbooks.
Chris - And what's the general opinion, people think this it's positive?
Abigail - Yeah, I think they do.
Chris - Medical students at universities elsewhere in the UK, do they get the same learning experience?
Abigail - I think most of them don't. I think there's only a few places that still do. I know one of my friends - she's at Keele - they just used plastic models. We did that the other week and it was a lot more difficult to figure out where things were when you can't actually sort of move them and see where they attach properly.
Chris - So the opportunity to do proper dissection seems to be really key to learning anatomy effectively which is a sentiment that's echoed even by surgeons in training too, including this one who's brushing up his knowledge of the subject by teaching it.
George - My name is George Marsden. I completed my foundation year here as a junior doctor in 2009 and I'm currently teaching anatomy for a year at Cambridge University as a junior anatomy demonstrator, and we also do on-call shifts at the Addenbrooke's Hospital in general surgery.
Chris - So, the idea is that for someone like yourself, because you've got to take higher exams in surgery as a would-be surgeon, doing something like this is a really good way to learn the anatomy.
George - Absolutely. Unfortunately, the university where I trained, we weren't able to do dissection and I really felt I missed out on anatomy which has always interested me, and I realised I wanted to pursue a surgical career path, and thought that teaching anatomy would be the best way of learning it for myself and almost give me a second chance to make up for last time.
Chris - So why are medical schools increasingly ditching dissection if it's so useful? And is Cambridge unusual in still teaching its anatomy this way?
Chris C. - My name is Chris Constant. I'm a clinical anatomist here in the Human Anatomy Centre at the Department of Physiology Development and Neuroscience. Cambridge University is a bit unusual in persisting with whole body dissection as our method of teaching anatomy. We believe it is the best way by far to teach anatomy to our students, so that when they go into practicing medicine, it will mean something to them.
Chris - Why if it's so important, have so many medical schools stopped doing it?
Chris C. - A number of reasons; cost is one, the effort it takes to run a body donation programme, ethical and legal issues, the difficult issues of respect, and basically the organisation of such a programme is actually very costly, very time consuming and very demanding in every way, and many universities have found alternative methods, things like plastinates, and models, and prosections, and atlases. And of course, to new electronic resources such as videos and electronic media which do have a lot to offer.
Chris - So students at Cambridge are very lucky to still be able to do whole body dissections. But one of my own most enduring memories of the first month of medical school was a nagging apprehension at the back of my mind about what it was actually going to be like to cut up a dead person. And talking to the students I met during my visit to the Cambridge dissection room, this seems to be quite a common experience.
Rowan - I'm Rowan DeSouza. I'm a first year medical student at Clare College, Cambridge.
Chris - When you were coming to medical school, were you at all concerned about the process of having to come and do dissections on dead people?
Rowan - Yeah. I mean, I think everyone is concerned. It's obviously something very, very different because it's human beings, it's very personal, but I kind of saw it as a benefit. And I think most people did because the Cambridge course is one of the best for anatomy because it does dissection. I mean, the first few sessions, they took us in very gently. They kind of covered up all the bodies, they kind of introduced us very slowly, and eventually, everyone gets used to it, and anatomy is fascinating, so it's very interesting. And once you're into the course, it's really good fun.
Chris - Were you worried?
Claire - Yeah and I still catch myself thinking this was a real human who was walking around and doing every day, normal activities and things, but I think you'll get used to it, and it's a really good way to learn.
Chris - Claire Blackman who's a medical student at Cambridge. So, if someone wants to donate their body for medical education, what should they do? Chris Constant again.
Chris C. - They need to make that clear by signing the appropriate Human Tissue Authority consent form which specifies what they wanted to be used for, how long we may keep their remains, how the material will be disposed off at the end; they need to inform their families. Their families need to agree, although that's not absolutely necessary, but we do like it if they're all in agreement, and of course, they need to keep the necessary paperwork available, so when the time comes, it is actually there and relevant, and ready to be used.
Chris - Can anybody leave their body or are there certain situations where you wouldn't accept a donation?
Chris C. - Anyone can donate their body after death. However, when the time comes, we have certain criteria with which we have to comply and there are certain criteria which result in our having to reject someone's remains. The donors are aware of that when they signed a consent form that there is a possibility that their remains would not be accepted.
Chris - And once the students have finished doing the dissections here, what do you do with the pieces they've dissected and then the body en masse?
Chris C. - To begin with, all the parts remain together for each individual donor's remains. They are not mixed so that they are all returned to one particular coffin and then cremated or buried in accordance with the donor's wishes. Prior to that, we have a committal service here in the anatomy centre in the dissecting room, at which students and others involved in dissection attend. The identities of the donors become known to these students. They have a chance to pay their last respects and indeed write a tribute to each of the donors, upon whom they have worked over the previous academic year. And it's actually quite a moving event. By the time we're finished with the remains, they are respectfully buried or cremated in accordance with the wishes of the donor, and everyone has their own remains. There's no mixing of parts.
Chris - And what would you say to anyone who's considering leaving their body for a medical student to learn on like this?
Chris C. - Well I would be very encouraging. First of all, it's an extremely generous act. It is something one can feel very good about. It benefits the students and ultimately, the doctors that are made from the students, and therefore, the patients in years to come. So what the donors are doing now in their life time, to be carried out on their death will benefit generations to come. I would be very positive. I think it's a great thing to do and I think you can feel you've benefited people after the good you do in life has finally come to an end.
Chris - Clinical Anatomist, Chris Constant from Cambridge University. If you'd like to find out a bit more about donating your own body, there are details about the process on the HTA's website, which is at hta.org.uk
35:22 - Donated to Science
Donated to Science
with Paul Trotman, PRN Films
There's a 10 minute sample of Paul Trotman's film Donated to Science below...
Kat - Would you donate your body to science after your death? We've had a few people on
Twitter, saying whether they would or not. Some people say they already had - hopefully they mean they have already arranged to donate, not thay're already dead and still on Twitter. Some people flat out refusing and others who know they should, but just can't bring themselves to do it. So what is it that actually drives someone to make this decision? We're joined here by Paul Trotman who's a physician and a film maker from New Zealand, who's created the film, Donated to Science. Looking at this exact issue from both the donor's perspective and that of the medical student. Hi, Paul.
Paul - Hi. How are you?
Kat - Yeah, good. Thanks for coming on the show. Let's just ask you a little bit about the background to this. Why did you decide to do this? It's a bit of a macabre subject.
Paul - I've been making medical films now for about ten years, even when I was first qualified, I actually moved from New Zealand to the UK, and spent my time doing locums and writing comedy in Edinburgh festival shows, and that sort of thing. I swore that the last two things I was going to do would be make documentaries or do medical stuff. I've ended up doing both and I'm having an absolute ball. So, you never know. I had just made a film about how you become an organ donor and we followed or recreated the journey of a couple of people to becoming organ donors. I used an actor to play the part of the donor, but then interviewed parents of people who'd become donors or partners of people who'd become donors, and all of the doctors and surgeons involved along the way. We ended up with a very powerful film about that sort of journey and I thought, well the other one that's similar is people donating their bodies to the medical school. But there's no way anybody would ever let me do a film like that. So, I was talking to a friend who worked in the anatomy department who said, "Well, go and talk to the professor within the department because she's quite interested in that sort of thing." And in the end, getting permission to make the film was actually the easiest part of it. I went to her, she had literally just come out of a meeting with some of the undertakers in the town who said, ":We really need something to show the members of the public who are wanting to donate their bodies what happens." Then I walked in the door and said, "I would like to make a film about people donating their bodies." And after six months of applications to ethics committees and examiners of anatomy and all that sort of thing, we got the permission. It's probably the only film that's ever been made that needed ethics committee clearance to make it.
Kat - Quite probably. So, how many people did you talk to and what sort of reasons did they give for wanting to give their bodies?
Paul - What we did was we contacted everybody on the list that were going to donate their body to the medical school and asked if they were interested, and we filtered them down, and we ended up interviewing six people of whom, three made it into the film. The reason that the three made it into the film was that, they knew that they were dying, they knew that we would get to film their particular bodies. The reasons people gave, the most common one was, "Me or a member of my family has had a lot of input from the health profession over the years and I just want to give something back." The next reason was, "I don't really want to have a funeral. I don't like funerals. I don't want to leave that as a burden on my family." And the third reason was, "Well, I'm not going to need it. I'll be dead."
Kat - I guess so. But you followed all these people all the way through and then talked to medical students as well. Now, how did the medical students feel about this whole thing because they - didn't they get to hear from the people who donated their bodies?
Paul - Yeah. What we did was we literally interviewed these patients and then waited for them to die. And then on the first day of med school, I stood up in front of the class and we said, "We're making a documentary. We're looking for volunteers." And we started off with about 30 volunteers from a class of about 200, and we whittled them down to about 20, who we followed all the way through. We had a couple of dropouts and we used about 10 of those students in the film. I think partly because they were in the film, they actually put a little bit more thought into what they were doing, and initially, we hadn't had the idea that you mentioned before, which is that, once they'd finished the dissection and we've done their last interview with them about what the dissection was like, and we filmed them saying goodbye to the body, and heading away, we said to them, "Would you guys like to see the interviews with the people you dissected?" Every single one of the student said yes. So we arranged a showing to show them these interviews with the donors and then we interviewed them again straight afterwards. We literally took them out of the viewing room where they watched the interview and then said, "Okay. What was it like?" And we got the most extraordinary reactions. A complete range from, "This guy is the same age as my father. He died young without any grey in his hair and I've just taken him to pieces." Through to, "I wish I'd seen this at the start because I now understand that there's really no connection between the person when they were alive and what remained of them that I dissected."
Kat - What do you hope to achieve with this film? Do you hope to achieve more people leaving their bodies to science or maybe more respect for students working with people?
Paul - I think really, all I want to do is let people know what happens and what happens to their bodies, and how they're treated. To let people look inside the dissection room, and then let people make their own minds up. I really didn't have an agenda when I set out to make the film at all. It was just to make a good film and to take people somewhere where they hadn't been before.
Kat - What has the response been like from people who have seen the film?
Paul - It's been very interesting. I mean, getting the film made in the first place was the easy bit. Getting somebody to broadcast it was a lot more difficult. It was initially with Television New Zealand who then changed their mind and decided it was too hard for them. Went to Television 3 in New Zealand which is another broadcaster who said yes and then got cold feet, but then stuck with it. When it was broadcast, there was an amazing reaction. It got huge audiences and the whole country was talking about it the next day and everybody was positive. The Professor of anatomy tried to walk across the university the next morning and barely made it from the number of people who stopped her. I happened to be working at the hospital at the time and the person I was looking for was just rolling her eyes whenever we got to another ward on our ward rounds, as somebody will say, "Paul, I saw your film last night. It was really amazing." I got the sort of reviews that I never, ever dreamed of getting. Just absolutely, praise from every quarter. It was just amazing.
Kat - Do you hope to take it further afield to maybe other countries in the world, perhaps here in the UK?
Paul - Yeah. It would be great. At the moment, we've got a showing at the Royal College of Surgeons next week on Thursday (13th January 2011) as part of their public education programme and it's a free showing, and they've got a booking number on their website, but it would be really nice to get it broadcast on TV here.
Kat - It does sound absolutely fascinating and have you got any plans to do this kind of thing again or are you going to turn to a different subject for your next documentary?
Paul - I've just finished a film about pig cell transplants, but we're also making a sequel to this film where we're following the same medical students through their clinical training on the wards. And again, we're not looking at the sort of physical - what they do. We're looking at the emotional impact that some of the things that happen to medical students have on the students.
Kat - And having known medical students, my ex-boyfriend was a doctor, it is amazing how wrapped up they get in it and then also in some ways, how detached they get from it. Are you hoping to capture those kind of feelings?
Paul - Yeah. What we found in this film was that the students actually grew up a huge amount between the day before they'd been in the dissection room for the first time, and the day they left the dissection room nearly two years later. And we're noticing similar sort of changes now as we're filming them on the wards. They're becoming a little bit more hardened to what's going on around them and they're finding some things incredibly difficult.
Kat - Wow! I really can't wait to see the next film that you make, but thanks very much for talking to us. That's Paul Trotman.
|A clip of Paul Trotman's film Donated to Science|
How often do you find something unusual in a dissection?
Chris - Well I can tell you Roger, that there are differences from one person to the next and sometimes when you do these dissections, you do find these slight differences from one body to the next in terms of the anatomy that some people have additional accessory blood vessels, some people have a different structure in certain places, some people have complete reversal of their internal organ - so-called situs inversus or dextrocardia, that kind of thing. So they do crop up, although rarely. Also, someone has got a very significant disease and sometimes that can be a reason that the body can't be used for dissection purposes because the disease means that the person can't learn the normal anatomy or architecture of organs because their disease is meant that they're not normal anymore.
45:46 - Naked Engineering - Artificial Limbs
Naked Engineering - Artificial Limbs
with Saeed Zahedi, Nigel Kingston, Blatchford Prosthetics
Meera - For this week's Naked Engineering, Dave and I are looking into prosthetics or artificial limbs. You've got us walking up and down in front of a building here. Why are we doing this?
Dave - Well we're looking at artificial limbs, particularly an artificial leg. If you want to make an artificial leg, you've got to understand how the natural one works, and what it's actually doing. So if you stop now and walk very, very slowly, first of all, your leg just swings forward, almost like a pendulum. The knee slightly bends as it does it which lifts your foot off the ground, so it doesn't drag across the floor. Then your heel hits the ground and then you roll over the top of that heel and you move forward, and then eventually, your toe leaves the ground, you push off with the toe, and then your leg swings forward again. So, if you're going to build artificial legs, then you've got an awful lot of things to think about and you don't have the advantage of muscles or any way of controlling them. So you have got to somehow copy these effects with, effectively, a much more simple mechanical system.
Meera - To find out how artificial limb designers mimic our bodies in this way, we've come along to Blatchford Prosthetics here in Hampshire to meet their technical director, Saeed Zahedi.
Saeed - Historically, the prosthetic leg has been making the sockets from wood or leather, metal, aluminium sheet, and then having components like a knee-joint and the foot and ankle joint, and a pylon connecting the two together which is like a peg leg, like a Long John Silver leg. If you think about the peg leg, you can just stand on it. You can hop on it, swing your leg outside and step from A to B in a very, very difficult way, very energetic way. When you apply a knee-joint, you can swing the leg a bit more easily and there's a bit less energy involved but that's about it.
Meera - You're really then using other parts of your body and compensating for the fact that there's this limited movement in the prosthetic.
Saeed - Exactly and I think that's where the major breakthrough has been for us, to understand better this nature of compensation.
Meera - In order to understand a bit more about this compensation and just how the body can react to using prosthetics, we've also got Nigel Kingston here, a fellow Blatchford employee, who at the age of 30, due to an arthritic knee joint, had to lose his left leg. So Nigel, I guess when you were first fitted with a prosthetic, how did your body compensate? What did you have to think about when simply just walking down the street?
Nigel - I think probably the biggest thing is slopes for an amputee. There are very few flat surfaces and it involves the whole of the body having to compensate. Something typical is if I'm standing on a slope with a standard fixed ankle. I'd be spending most of my time weight bearing on my sound side which is the right side. You can feel a lot of pressure in your lower back. My right thigh muscle is twitching because after awhile, it's just fighting and saying, "I want to give up now. I've had enough."
Dave - So the fundamental problem is that if you've got a fixed ankle at 90 degrees, if you try to line that up with a slope of 10 degrees, you'd either got to be sort of hanging off in mid-air, leaning forwards or you just got to almost ignore that leg entirely.
Nigel - You're entirely balancing on the sound side really and the prosthetic side is just there as something of a minor support.
Meera - So Saeed, as Nigel mentioned, the real problem to-date has been uneven surfaces and to do with this has been the fact that prosthetics have had fixed feet. So your new design here at Blatchford, the Echelon Foot, a flexible ankle prosthetic, overcomes that problem.
Saeed - The way it was conceived was basically trying to find out what are the limitations that the amputee like Nigel will be facing. And to do that, we started looking at the way the ankle and foot function in relation to the ground. So we started looking more closely at the function of the ankle and we looked at their way the muscles work and the muscles on the normal human body, effectively, they can stretch but in a controlled manner. They can generate forces at the rate which is in the control of the person.
Meera - We have one of your Echelon Foot designs here in front of us and this one is about a foot long and it's made of carbon fibre.
Saeed - It has about three elements, the toe spring which is made up of carbon fibre composites and that toe spring acts like a cantilever spring which enables the body mass energies to be absorbed and then returned at the right moment in the gate cycle to effectively deliver some sort of a push-off force in the absence of the active calf muscles that is lost in the amputation.
Dave - So, as the foot rolls forward, you're storing energy in that spring which is then released as you push off.
Saeed - Correct. You're almost bending that spring to its limit and then at the right moment, when you take the weight off from the prosthetic side, then that's released. The other element is the heel spring which again, is effectively designed to be able to absorb the energy which is created at the point of the collision. If you can visualise the gate cycle as a rhythmical sequence of collision and push-off, you want to be able to absorb the energy at the collision and use some of the energy during the push-off phase to be able to assist the amputee. This sequence of or the rhythm of collision and push-off needs to be smoothed out. Hence, we've got the hydraulic element in the middle of all this.
Meera - This is attached really at where the leg would be attached to a foot.
Saeed - That's almost roughly where the ankle joint is. That element effectively acts as a damper. Now if you have got a damping element in there, the amputee naturally under natural launch and control, they can effectively bring their body into the right orientation. Hence, the combination of the hydraulic damping and the carbon fibre composite spring, very much acts like your muscles and that's why we called it the biomimetic design.
Meera - And now Nigel then. So, when you were first fitted with a prosthetic, it did have a fixed foot, but you're now wearing the Echelon Foot design. What differences have you felt then?
Nigel - Shortly after trying it, I realised I had all my foot to the floor and then I was actually feeling more secure, more stable. I was able to walk much longer distances. It was not necessarily about the time of the distance, it was about the lack of fatigue that I was feeling.
Meera - This type of prosthetic, how would you summarise the real benefits of them?
Nigel - I think we're looking at major advance in the comfort, the functionality, and the general usability of the new generation of feet. We actually want to, as an amputee to be able to walk more easily. The new generation are enabling amputees now to do what they want, when they want, and I think it's the way forward for us.
Chris - Nigel Kingston and Saeed Zahedi from Blatchford. They were showing Dave and Meera how to engineer artificial limbs and specifically ones with flexible ankles, so they can more closely mimic the process of human locomotion, resulting in more comfort for amputees.
52:58 - Are humans the only animal to drink milk from other species?
Are humans the only animal to drink milk from other species?
Diana - Most of us will have seen our pets and various garden wildlife taking advantage of a source of cow's milk on occasion. But are we the only ones to drink it habitually?
Oliver - I'm Oliver Craig and I work at University of York in the Department of Archaeology.
In fact, we are - well at least, we are when we're adults. All juvenile animals can drink milk and that's because they have the enzyme lactase to digest the milk sugars. But the genome that makes the enzyme gets switched off when they get to a certain age, so as adults, they can't drink it. Most humans in fact can't drink milk as adults and there's only a very small fraction of the world's population who can. What's really interesting of course is that those people live in a very geographically restricted area, i.e., Northwest Europe and some parts of Africa. So it's a really interesting question as to why only a certain part of the population can drink milk.
If you're lactose intolerant, you don't possess this enzyme lactase. So basically, the lactose that's in the milk doesn't get digested. It's a disaccharide and it passes straight through the gut and goes into the colon, and it can cause all sorts of unpleasantness, including what's generally quoted as some kind of explosive diarrhoea, and is a really, really nasty condition if you can't actually break these sugars down. But it also causes problems with water retention and all sorts of other problems as well. So really very ill, bad stomach and not actually been able to digest the sugar itself. So at some point in our history, it was a selective advantage for people in Northwest Europe at least to be able to drink milk.
Diana - But does being lactose intolerant really put you to selective disadvantage?
Oliver - Well, you wouldn't have thought it would really, would you? It's not going to impact on your daily life massively. It's only going to be selective disadvantage if there's a real advantage in being able to drink milk, fresh milk. It comes back to the question then, why is being able to drink milk such a selective advantage? The answer is that we really don't know and that's what we're trying to research and find out. The first thing that we need to do is find out when or at what point in our history did that need to drink milk actually occur?
Diana - As far as we know, humans are the only animals to drink another species milk regularly, but only a small proportion of humans have the lactase enzyme. Cats and dogs are often seen taking delight in a serving of milk, though I'd rather not consider the consequences. An excellent find on our forum came from Jackass Penguin who cited the Red Billed Oxpecker, a bird that can perch on the udders of an Impala and drink its milk. Elsewhere, in Isla de Guadalupe, feral cats, seagulls, and sheathbills have been observed stealing the milk directly from the teats of elephant seals. So perhaps milk stealing does happen a little more than we currently know.