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Medical Cannabis; Hidden Blood in the Urine; Ageing and Immunity

Inside Health looks at the evidence for medical cannabis. And hidden blood in the urine is frequently picked up by sensitive dipstick tests, but what should happen next?

There are questions in Parliament following the story of 6 year old Alfie Dingley who was refused medical cannabis to help relieve his epileptic seizures. But what is the body of evidence for medical cannabis and does the reality live up to the hype? And age, immunity and the poor performance of this season's flu vaccine. Why do our defences decline as we get older and what can be done to improve vaccines that aim to protect the elderly against flu? Plus blood in your urine - pee the colour of Ribena is hopefully enough to drive anyone to their doctor - but what about tiny traces invisible to the naked eye frequently picked up by sensitive dipstick tests? If that has happened to you listen to our comprehensive guide.

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28 minutes

Programme Transcript - Inside Health

Downloaded from www.bbc.co.uk/radio4

 

THE ATTACHED TRANSCRIPT WAS TYPED FROM A RECORDING AND NOT COPIED FROM AN ORIGINAL SCRIPT.  BECAUSE OF THE RISK OF MISHEARING AND THE DIFFICULTY IN SOME CASES OF IDENTIFYING INDIVIDUAL SPEAKERS, THE BBC CANNOT VOUCH FOR ITS COMPLETE ACCURACY.

 

 

INSIDE HEALTH – Programme 7.

 

TX:  20.02.18  2100–2130

 

PRESENTER:  MARK PORTER

 

PRODUCER:  ERIKA WRIGHT

 

 

Porter

Coming up in the next half hour:  Ageing and immunity, why a better understanding of how our defences weaken as we get older is influencing next year’s flu vaccines for the next season.

 

Clip

Chambers

The flu virus is constantly changing and it changes the proteins on the cell surface.  So, what the World Health Organisation tries to do is it tries to guess what flu is going to be present in the next winter season.

 

Porter

Well that’s a challenge isn’t it for every age group.

 

Chambers

For every age group, yeah.

 

Porter

What is it specifically about the over 65s that present such a challenge?

 

Chambers

Now unfortunately as we get older our immune system doesn’t work as well.  So, when we inject the flu vaccine into older people unfortunately it’s just not generating a proper immune response.  And so, in older people you tend to get around perhaps 10% of people responding.

 

Porter

And blood in your urine, pee the colour of Ribena is hopefully enough to drive anyone to their doctor but what about tiny traces invisible to the naked eye.  The microscopic haematuria commonly picked up by dipsticks used in medicals?  If that has happened to you, don’t miss our comprehensive guide coming up later.

 

But first cannabis and the story of six-year-old Alfie Dingley, who has been in the headlines after his mother lobbied for him to be able to take a cannabis-based medication to help relieve his epileptic seizures.  Something he had been receiving abroad with some success but which the Home Office has refused to let Alfie have in the UK.

 

His story caught our attention at Inside Health, not least because, like many of you, we have long been intrigued by claims made about the benefits of medicinal cannabis.  But does the reality live up to the hype?

 

Professor Orrin Devinsky is Director of New York University Epilepsy Center, and lead investigator of a trial of cannabis-based treatments for epilepsy published by The Lancet.  So, let’s start by clarifying what is meant by medical cannabis, what did he actually test?

 

Devinsky

Medical cannabis refers to a large variety of compounds or substances.  The research that I conducted was using cannabidiol which is the major non-psychoactive, that is does not produce a high sensation, ingredient or compound in cannabis or marijuana.  So, it was produced by GW Pharma, a British company that grew cannabis plants and then extracted cannabidiol, a single compound, the drug we used was 99% cannabidiol, which I’ll refer to as CBD and had essentially no THC or none of the many other hundreds of compounds present in cannabis. 

 

Porter

And what did you find when you used this in people with epilepsy, what results did you get?

 

Devinsky

So, we went through two stages, we first, together with many other centres around the world, started giving it out and in what we call an open label.  That means I know what I’m giving, the patient and parent knows what they’re getting and adjust the dose and there’s no placebo group and that’s the challenge of open-label studies.  But those studies were quite encouraging, the safety profile – that is the side effects – were also very favourable.  So, for those reasons we went for it with large randomised control trials.  And those are the trials where nobody knows – myself, the other investigators, the parents or patients – no one knows if they’re receiving the active medication or placebo.  So, we did trials and three of them have now been completed and essentially in all three trials the CBD – the cannabidiol – was quite significantly more effective than a placebo in reducing convulsive seizures or drop seizures, which are bad seizures for these children and young adults.

 

Porter

What do we think the mechanism might be?  Is it a direct effect of the CBD on the brain or is it some effect that it’s having on the medication that they’re taking already for their epilepsy?

 

Devinsky

It’s an excellent question.  We believe the primary mechanism is a direct effect on the brain.  CBD has multiple effects on different receptors within the central nervous system or brain and we’re honing in on a few of the receptors we think are key targets although humbly in 2018 I think we have to say we don’t know.  The second part of your question is could it be affecting levels of other medications.  The answer is that may be a small part, we think, of why it works in some patients.  The only drug that we know that it has a significant interaction with is one called clobazam and it raises the metabolite of that drug, which is an active metabolite and can potentially produce side effects and potentially produce therapeutic effects.  But we see roughly the same benefit in children, in young adults, who are not on that drug.  So, based on animal studies and based on a lot of human data at this time we believe that the primary mechanism by which it works is a direct effect on the brain.

 

Porter

Where might this fit in to your existing choice of medication?  I mean given the difficult legal status in some countries, given the lack of licensing are there not other drugs that you could use to achieve the same effect?

 

Devinsky

There probably are.  I think with all of medicine we should look at risk and benefit.  I think for this medication, CBD, it is roughly as effective as many of the other drugs that we have to treat these severe epilepsies and I do believe, from my experience of now treating hundreds of patients, that the side effect profile is actually more favourable.  Some of the drugs are really potentially more toxic.  And the long-term effects of any drugs are not well studied – CBD or especially the ones that doctors, like myselves [sic] and those in the UK have been using for decades.

 

Porter

What’s the situation currently in America?  Can patients access this medicine?

 

Devinsky

America’s in a bizarre state I would say, in that we have a federal government that considers CBD one of the most dangerous compounds on the planet, which I believe is ludicrous.  And then we have roughly 30 states, well more than 60% of the US populous, has access to medical cannabis.  Now that’s not pure CBD, the medical cannabis is from the plants that has some amount of THC, the psycho-active component, some amount of CBD and then many, many other compounds present and it’s never been adequately studied for safety and efficacy.  So you have these very strange mixtures where we are extreme in that the federal government says this is the most dangerous thing imaginable and then states are approving varieties of compounds that may vary from batch to batch for these kids or young adults and we don’t really know the side effect profile, especially when you give a psychoactive compound like THC to a two-year-old child, it’s really a strange situation and from one, from my perspective, in which we desperately need more scientific data.

 

Porter

Professor Orrin Devinsky talking to me online from his busy clinic in New York.  And listening to that in our Glasgow studio is our resident sceptic Dr Margaret McCartney.  Margaret, at least Professor Orrin is only looking at one compound here, which makes things a little bit simpler.

 

McCartney

Oh yes and for a chemical that we know is psychoactive and may have some use in medicine our trial evidence is really pretty shameful.  Up until 2014 there had been two reviews done, trying to gather together all the randomised control trials, the highest quality evidence for use of cannabinoids and less than a hundred patients had been randomised to a treatment or not.  And that means that there’s very little data to give people high quality information about what might work.

 

Porter

And when you say cannabinoids we didn’t know actually – you can’t be sure that one trial’s using anything like the same as the next one.

 

McCartney

Yeah, so when you’ve got  no standardisation, when you’ve got lots of things in the mix, it’s really difficult to tease apart what it is that you’re actually using to treat someone as an intervention.

 

Porter

But Margaret, the trial that Professor Devinsky led, I mean the first one was open label, he admits that that’s got limitations but to go on to do RCTs that’s the sort of thing presumably that you want to see?

 

McCartney

Oh absolutely, that’s ideal, that’s exactly what we want and really lots of them, the bigger the study the more powerful it is and the better able we are to know that our results are reliable.  But the studies that Professor Devinsky mentioned there, they’re not published in full yet, they’ve been presented at scientific meetings only, so we really need to see the full detail on them.  And also, they apply to children with specific syndromes, not perhaps to children with epilepsy more broadly.

 

Porter

Does its legal status impair the process as well, it must make it all much more difficult?

 

McCartney

Well this is something, if you look at the literature, this is something that many researchers really complain about most bitterly.  Cannabis is put as a class 1 categorisation from the Home Office, so it’s a class 1 drug and that creates real bureaucratic hassles for people.  They’re defined in part as drugs that don’t have a therapeutic value and are addictive.  But the problem is that you won’t find the therapeutic value of them or not if you’re not able to do research.  And, for example, some researchers have said that they’ve had a licence to use a product for eight weeks but that licence has run through very quickly, it’s not given them enough time to do research, even placebo cannabis, which you would obviously need for your randomised control trials comes under the same licence and these very restrictive time periods that they can be used for.  And that creates a huge hassle for researchers who are under pressure to get their work done and you can see why it becomes an unattractive area of study if it’s so difficult to do for these very bureaucratic reasons.

 

Porter

So, Margaret, from your perspective at the moment, we need far more evidence, is what you’re saying, that this actually works and that it’s safe?

 

McCartney

Well far better evidence as well.  What we need is high quality information not hype.

 

Porter

Indeed.  Thank you very much Margaret.  And as ever there are links to more information on the subject on the Inside Health page of the Radio 4 website.

 

The worst of this year’s flu season may be over, but the NHS is already planning for the next one.  NHS England has just written to GPs and community pharmacists instructing them to offer a different type of flu vaccine to the over 65s this October, amid growing concern that the existing vaccines don’t offer them enough protection.

 

The new vaccine contains an extra ingredient, an adjuvant, which boosts how older people react to the jab, hopefully prompting better immunity.  But what is it about an older immune system that makes it less reactive?

 

Arne Akbar is Professor of Immunology at University College London.

 

Akbar

The immune system, the best way to visualise it, is it’s an army, an army of many different parts.  Now ageing of the immune system is not in just one component, each one in turn might go wrong but as with every good army you need communication and the communication also breaks down between all the different parts of the immune army.

 

Porter

And in terms of age, when are we talking about this becoming significant?

 

Akbar

Our immune system, like most organs in our body, starts ageing from the time you were born.  But when you’re young you have very few of the older cells in you and these slowly accumulate with time.  With the research that we do in my group we consider young people to be under 40, so that’s very optimistic for most people.  And our cut off for an older age group that we study is over 65.  Until you get to 65 you don’t really see very many changes but I think anecdotally you know that there’s some old people who run marathons in their 70s, so not everyone ages at the same rate.  Some people will show problems even in their 40s.  So, if you like, the generals of the army are the white cell called a T-lymphocyte.  A T cell is very small, it’s almost – you can’t see it with the naked eye – but you can actually, with the techniques we have, look within the T cell and the different elements of how it works, it’s all wired up a bit like a radio, you have knobs that turn the cell on, you have knobs that turn it off, things that are changed that you can actually modulate and change different functions.  And we find that there are lots of changes that these cells have as you get older.

 

Porter

So, actually what we’re seeing is a change in the way that the cells function as we get older.  And is that a consequence of the cell itself being older?  I mean if you’re looking at T cells of somebody in a 65-year-old how old is that T cell?

 

Akbar

Some of those cells you’ve had all your lives.  The important ones that regulate what goes on are the ones like the T cells.  They’re produced in an organ called the thymus but unfortunately, as you get older, the thymus shrinks and stops producing more cells.  So, the generals we have are the ones you’ve had most of your life, from when you’re past puberty are the ones you have the rest of your existence.  And they get old and once you have old generals they don’t regulate the whole army as well as they used to.  And the way to identify ageing in the immune system is to notice the fact that older people get more cancers, older people don’t respond as well to treatments for infections and older people have decreased ability to respond to vaccines – it’s all part of the same problem. 

 

Porter

Now we’ve seen this with the vaccines – with the flu vaccine recently, in the last couple of years, the response has not been good.  Is that an age-related thing do we think?

 

Akbar

It is.

 

Chambers

My name is Dr Emma Chambers, I’m an immunologist at University College, London and I also volunteer as a vaccine ambassador for the British Society for Immunology. 

 

Porter

Just explain the problem that we’re facing at the moment, this year and in previous years, with the flu vaccine?  What was going wrong there?

 

Chambers

So, the flu vaccine’s actually a very difficult vaccine to design in itself.  The flu virus is constantly changing and it changes the proteins on the cell surface.  So, what the World Health Organisation tries to do is it tries to guess what flu is going to be present in the next winter season.  And because the flu vaccine’s grown in egg it takes at least a six-month period to grow.  So, actually they’re guessing, first of all, what virus is going to infect us in a year’s time and as a result generate a vaccine against it.  Unfortunately, sometimes, their guess is not necessarily correct.

 

Porter

But that’s a challenge, isn’t it, for every age group?

 

Chambers

For every age group yeah.

 

Porter

What is it specifically about the over-65s that presents such a challenge?

 

Chambers

So again, it comes back to the immune system not working very well.  So, when we inject the flu virus – a flu vaccine into older people unfortunately it’s just not generating a proper immune response.  And so, when you – in older people you tend to get around perhaps 10% of people responding.  You’ve got to think on the positive side, it does mean one in 10 people will have a beneficial effect of having the flu vaccine.  And something I would like to emphasise is although it might not prevent you from getting the flu it will reduce the severity of your disease.

 

Porter

But 10%, given that these are the most vulnerable members of our society from flu, I mean that’s pretty poor, we’d like to do a lot better, so how can we use our understanding of the ageing and the research that’s been done here to improve the efficiency of the vaccine?

 

Chambers

There’s a couple of ways in which we can target this.  The first way is we’ve started vaccinating children and we found that children are super-spreaders.  And so, when children are affected with flu virus they’re often able to infect their grandparents.  So, one way by protecting the older people is actually vaccinating other people.

 

Porter

So, that’s protecting them indirectly.

 

Chambers

Indirectly – through herd immunity.  And another way that we are using in the lab is to try and make flu vaccines work better.

 

Akbar

One thing I haven’t told you about the immune system and what goes wrong is that older people have baseline inflammation.  That is to say it’s like fighting a battle, if you take the analogy with the army again, but in a very hot climate.  Our bodies heat up – not physically heat up but in terms of the amount of inflammation we get it’s increased with ageing and that somehow interferes with the efficiency of the immune system, it’s like fighting a war in a desert.

 

Porter

So how would that affect the response of somebody to a vaccine?

 

Akbar

So, what we’ve done recently is to actually perform a study where we targeted the inflammation by trying to reduce it.  And to do this we used a drug, it’s a safe drug because they’ve been through many trials with this, and we only give it for a very short time – four days, two tablets a day.  And this inhibits the inflammation temporarily in older humans and we ask if we challenge these individuals before and after we block the inflammation do we get a better response afterwards.  In the study that we’ve just had published suggests that yes we do, we do enhance the immune system by cutting down this overheating that we’re getting in older people.

 

Porter

So, to go back to your analogy of the troops in the desert, effectively what you’re doing is air conditioning the desert, let’s say, bringing the temperature down so the troops can perform better and you get a better response to the vaccine.  Have you shown that you actually get more immunity as a result of the vaccination?

 

Akbar

So, we haven’t looked at vaccination, we’ve looked at an immune challenge.  We inject a product into the skin of volunteers and this product is derived from a virus, the virus that gives you chicken pox, varicella zoster, and it’s not the virus itself but a product of it which creates an immune response, almost like a vaccination.  The next step is then to test the question of whether this would actually work in a proper vaccine setting, for example influenza.

 

Porter

So, it might be that you’d give some form of anti-inflammatory before immunisation with an influenza vaccine in the hope that the response would be better?

 

Akbar

So, that’s exactly what we’d like to test.

 

Chambers

So, we think that in older people there’s this chronic low-level inflammation.  And what it means is, is that the older person’s immune system is constantly trying to dampen it down, to try and cool the inflammation and as a result it’s not able to see infections or vaccines very well because it’s too busy trying to cool down the inflammation.  And so, our research shows that if you inhibit inflammation for a short time before we administer the vaccine, we’re only talking about four days here, we can actually reduce the inflammation in older people and then that means that they’re then able to see the vaccine as a younger person would.

 

Porter

So, this background inflammation acts as a sort of fog that’s obscuring the new challenges like vaccines trying to get in.  And you would hope that it would clear the view.  What sort of thing’s causing the inflammation though, why do older people have this background level?

 

Chambers

So, it’s not something that’s fully understood at the moment.  There’s some research that suggests that as we age our gut becomes more leaky and as a result bacteria which normally is happily resident in the gut manages to escape and get into the blood stream and as a result the white blood cells release proteins saying – ahh there’s bacteria around, we need to calm it down.  And so, we think that might be why there’s a chronic low-grade inflammation in older people.

 

Porter

We’ve been talking about the flu vaccine but presumably this problem applies to any vaccine given to older people and old in terms of the immune system’s not actually that old. 

 

Chambers

No, this is very true, we know for example the shingles vaccine works much better if you get it at 70 years old rather than 79.  And we know this is the case for the majority of vaccinations we currently give out in the UK.

 

Porter

Dr Emma Chambers and Professor Arn Akbar.  And there is a link to their research into using anti-inflammatories to boost immune response and more details on the proposed changes to next season’s flu vaccines on our website.  Where you will also find details on how to get in touch.

 

Frances emailed asking for some guidance about a common problem often turned up during medicals – blood in her urine.  Not that she had noticed.

 

Frances

At a routine pre-op before my surgery to my surprise, as I hadn’t noticed anything, I was told by the nurse that I had blood in my urine which I should have investigated.  As a result, I was referred first for a urinary tract ultrasound and then for a bladder examination.  The cystoscopy report recommended that the GP referred me to a kidney specialist but this wasn’t taken any further and because both the pre-op nurse and the nurse at the urology clinic said that they too had been found to have blood in their urine I left it at that.  But since I’ve been wondering whether I should raise it again with the GP.

 

Porter

I think I know just the person to ask Frances.  Somerset GP Dr Jon Rees chairs the Primary Care Urology Society and sees lots of patients in your situation.

 

Rees

I’ve just come straight from an all-day urology clinic where I have seen a lot of people with blood in their urine, I’ve probably seen somewhere between 10 and 15 patients with this problem today.  If we go out in the street and tested about a hundred people we estimate somewhere in the region of 2-3% of the population, if you check their wee, you would find blood in it.  So, it’s a very common problem and of course the vast majority of those people never know they have it and can have it for years before it’s finally picked up by testing. 

 

Visible blood in the urine, much less common, and we know that visible blood in the urine is quite risky, we know that in about 20% of people who see unexplained blood in their urine there’s something significant going on.  And by that I predominantly mean kidney cancer or bladder cancer – those are the two specific conditions that we’re most concerned about.  And what we sometimes do is we extrapolate that because that is a significant risk in people with visible blood in the wee we assume therefore it’s also a significant risk in those with non-visible blood in the wee.  Whereas of course the vast majority of those people they’re actually much, much lower risk.

 

Porter

So, the problem is we know that visible blood is a serious side effect, could be bladder cancer for instance or kidney cancer, so it’s only natural to assume that little tiny microscopic traces might be an early sign of the same thing.

 

Rees

Absolutely and that is the assumption that’s been made.  But unfortunately, that assumption isn’t correct and in patients with no symptoms and with non-visible blood in the urine what we try and do when we work out what to do with people with this problem is to stratify risk, we’re trying to work out who should we be worried about and who shouldn’t we be worried about.  So, there are a few things that can help us do that. 

 

So, firstly, symptoms, so if someone has non-visible blood in the wee and they have some symptoms, particularly new symptoms and by which I’m talking about either pain over their kidneys, loin pain or urinary symptoms like stinging when you wee, frequency, urgency, those sorts of symptoms, then that suggests that something might be going on and the risk is higher.  So those sorts of patients should definitely be assessed.  Increasing age – so the younger you are with non-visible blood in the wee the lower the risk that there’s anything significant going on behind it.  So, the older you are the more you should be concerned if you suddenly have blood discovered in your urine on testing.

 

Porter

What do we mean by old in this respect?

 

Rees

There’s no absolute.  The cut-off that’s been chosen is 40 in the UK, so patients under the age of 40 we pretty much don’t worry about tumours in asymptomatic non-visible blood in the wee.  Patients over the age of 40 do get assessed.  So that’s the kind of cut-off. 

 

And then the final risk factor that I always concern about is smoking.  And we know that smoking doubles at least the risk of patients developing bladder cancer, which is our main concern here.  And so, people who are heavy smokers who are found to have blood in the wee, again that might increase my threshold for wanting them to be assessed.

 

Porter

And when you say assessed, how should that be and how urgently?  So, say a patient comes into me, they’ve had a life insurance medical, we find microscopic traces of blood on dipstick testing, they’re 55, my age, what do you do with them then?

 

Rees

The first thing always is to repeat it.  I would never expect someone to be referred on, on the basis of a single positive finding.  So, the national guidance is that if two out of three tests are positive then that should mean an onward referral.  And that’s not a rapid two week wait, one of the extreme urgent, I’m very worried about cancer referrals, it’s a more routine referral.  And they would tend to come – those patients – would tend to come and see us in the haematuria clinic.  They would tend to have two tests, one is a thing called a flexible cystoscopy, I’ve done about 20 of those today, and that’s looking in the bladder with a little floppy camera, which takes about two minutes.  And that’s to check for any tumours or stones in the bladder.  And then also some sort of imaging further up, some imaging of the kidneys mainly and that’s either by ultrasound or sometimes by CT scan.

 

Porter

So, looking at Frances’ example here, she had an ultrasound scan, she had a cystoscopy – an examination of the inside of her bladder – so if you don’t find anything at that stage, is that it?

 

Rees

So, this is the classic scenario and we know from a famous study done in Plymouth a few years ago that showed that only about 4% of patients who get referred with non-visible blood in the wee, in this sort of scenario, are actually found to have any significant problem urologically.  So, that leaves 96% who are told everything’s fine.  And of course, the natural question, which I get asked all the time, is okay well you’re telling me everything’s fine, but I have blood in my wee, that’s not normal is it.  And so, we know that for most of those patients that blood is coming through from their kidneys and the sort of story I tell people is to kind of visualise their kidneys as a glorified sieve and the sieve is keeping back the cells in the blood and letting through the fluid that becomes the urine.  And of course, if that sieve becomes slightly leaky red blood cells, which are tiny, start to leak through into the urine.  And our dipstick test that we now do are so sensitive they pick up an absolutely tiny amount of blood in the urine.  So, that tends to be what’s happening.  So, we would want to check the kidney function of any patient who’s been given the urological all clear and that’s very easy to do and we generally would do that in primary care.  So, we do a blood test, to check their kidney function and we would do a urine test to look for protein and we would check their blood pressure to see if that was okay.

 

Porter

And if they’re given the all clear by a clinic like yours and they come back to me, I do those basic tests that we can easily access in general practice and they’re all clear, is that it then?

 

Rees

There’s one condition that we just have to keep our minds alert to and that’s a thing called IgA nephropathy and that’s a condition where the kidneys get damaged when the body’s fighting off a viral infection.  And that can cause persistent blood in the wee.  And the problem with that condition is about 20% of people with that condition progress later in life to kidney failure.  And whilst it’s not common what we do want to do is spot those people early so that their kidneys can be looked after at an earlier stage before they develop symptoms.

 

So, for as long as these people who have had these negative investigations for as long as they continue to have blood in their urine then once a year they should be having those kidney blood tests repeated.  And that creates a sort of early warning system.

 

Porter

Do you think we might be doing too many dipstick tests?

 

Rees

There’s no doubt that my clinic is full of people who’ve had dipstick tests done in all sorts of clinical situations.  Not always entirely appropriate.  One of my big sort of bee in my bonnet is that we see an awful lot of people who come into the haematuria clinic who’ve had blood in their urine picked up at medical screenings, through work or other suchlike.  We know that there is not evidence to support the use of testing for blood in the urine on dipstick, it’s a screening test, but unfortunately that’s often what happens.  The problem there of course is if you’re taking someone with no symptoms, often at a younger age, and the population who are engaged with screening are often the healthier non-smokers, then actually what we’re doing is we’re testing the lowest risk and we’re missing those at the highest risk of us finding anything of significance.  So, we’ve got to be very careful about our use of dipstick testing and of course the more you have your wee tested the more likely you’re to be found to have blood in your urine, the more likely you’re to end up in my clinic.

 

Porter

Dr Jon Rees.  And, just to be clear, while microscopic traces of blood are generally not serious, obvious blood in your urine, whatever your age, should always prompt a visit to your doctor.

 

Just time to tell you about next week’s programme when Margaret McCartney looks at the latest technology revolutionising care for some people with Type I diabetes, and I meet a pioneering team using stem cells to repair cartilage in damaged knees.

 

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