SciBlogs

Archive September 2009

a special kind of donation Alison Campbell Sep 30

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As I left the office this afternoon I said to my colleagues, ‘I’ll be in a bit later tomorrow, I have an interview with a vampire.’ At which they all laughed, because they know this means I’m off to my regular appointment at the NZ Blood Service centre, over by the hospital.

I’ve been donating for a few years now. For a while I gave whole blood (plasma, platelets, red blood cells, the whole lot) but for whatever reason this used to see me getting a bit anaemic & I could only donate 3 times a year max. So I discussed my options with the Blood Service staff & the upshot was that I changed to being a plasma donor (the process involved is called plasmapheresis), & make a donation every 2-3 weeks.

So what does plasmapheresis involve? Well, tomorrow  I’ll get up early (as usual), walk the dog etc, & have a good breakfast (very important to do this before donating). Then, when I arrive at the Blood Service, the first thing I’ll be asked to do is present my donor card (I’m O+) and confirm my name & date of birth. (This is done 3 times in the visit, to make sure they’re dealing with the right person throughout.) Then I complete a form providing a range of details about my health status & hand it in at the desk. Soon after that one of the staff will invite me into an office, where my haemoglobin levels are checked using a drop of blood from a thumb-prick, my blood pressure is taken (& my weight0, & the details I’ve provided are verified & discussed. Then – if all’s well – it’s on to the donation room.

There, the phlebotomist will check my details again & I’ll hop up onto a nice comfy reclining bed/chaiir thing. (They have wireless at the Hamilton centre so I’ll be able to read my favourite blogs while I’m there!) To one side of the bed is the plasmapheresis machine & on the other (usually) is a locker with magazines & a space where the staff place a drink of one’s choice & also cookies :-) One arm goes up on a pillow on an arm rest & an inflatable cuff goes round the upper arm; I’ll be asked to repeatedly clench that fist on a rubber ball while the cuff is inflated & that will bring up the veins. (Mine are pretty pathetic really & in fact only the right arm is suitable for sticking needles in.) The phlebotomist will wipe down the crook of my elbow with antiseptic wipes, check once more that I am the right ‘me’, & slide a catheter needle into my vein. This causes a brief moment of discomfort (ouchy ouch ouch, during which I wriggle my toes & look away!) – but I figure that the people who’ll be getting my plasma are almost certainly enduring far worse, & the moment’s quickly past.

Next they’ll take 3-4 vials of blood for testing (to make sure that my blood chemistry is OK & there’s nothing going on that shouldn’t be), before plugging in the tubes connecting me to the plasmapheresis unit. This is a complex-looking machine that will quietly hum away for the next 40 minutes or so as it draws off around 700ml of plasma. The system that’s used is ‘discontinuous flow centrifugation’, where the machine goes through a number of cycles of drawing off around 450ml of whole blood & then spinning that in a centrifuge to separate the plasma from everything else. It’s rather neat watching that happening & seeing the yellow plasma trickle down into the collection bag. Once the 450ml (or thereabouts) of whole blood’s been drawn, the centrifuge stops, the arm cuff deflates, & the cellular components of my blood (plus platelets etc) are returned to my body through the catheter tube with enough plasma to keep it fluid. An anticoagulant’s added to the blood to ensure there’s no clotting (which would otherwise be quite likely) – this can make your lips tingle during the first return cycle :-) Then the cycle repeats (4 times, in my case) until they’ve drawn off the volume of plasma that’s allowed for someone my age & weight.

At which point the machine beeps shrilly, and the phlebotomist comes back, checks everything’s completed, removes the catheter & tubing (this doesn’t hurt), & puts on a nice technicolour fluorescent pressure bandage. And I’ll hop up, collect my bits & pieces & perhaps a toffee or two, & make an appointment to come in again in a couple of weeks.

So – blood donation’s easy – and it’s an an easy way to help other people. I used to worry at times that I don’t do enough in the way of community involvement, volunteering, that sort of thing. And then my husband sat down with me & said, ‘Look. Every couple of weeks you give up time to do something that is almost certainly saving a life. So get over it – you’re doing good.’

And that gave me a warm fuzzy. So if you’ve ever thought about donating blood, make an appointment at your local Blood Service centre, & go along to find out if you’ll be suitable as a donor. It’s an easy way to make a difference in someone else’s life.

funny pictures of cats with captions

thoughts on xenotransplantation Alison Campbell Sep 30

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This is a re-post of one I wrote earlier this year. For a bit of background: one of the topics that year 13 Biology students can study requires them to do research around a ‘current’ or ‘controversial’ issue such as stem cells or xenotransplantation. I wrote a brief one on stem cells (really, more a case of pointing in the right direction), but then did a longer piece on xenotransplantation, which follows here.

The daughter said recently that having done stem cells, I should also look at some of the other topics you can choose from for your research exercise. She suggested xenotransplantation, as it seems quite a few of her friends have chosen that one. So I’ll have a go :-)

Xenotransplantation is where cells, tissues, or organs from an individual of one species are transplanted into an individual from another species. (‘Xeno-’ means foreign; you see it also in the word ‘xenophobic’, meaning fear of foreigners.) One of the drivers for investigating xenotransplantation into humans is the fact that there is a global shortage of human organ donors, while the use of species such as pigs has the potential to provide an almost unlimited pool of organs. (My driving licence identifies me as a donor. But I”m fully aware that my wish to give any useful bits to others, after my death, might not be honored if members of my family objected to the idea. Hopefully they’ll respect my wishes. After all, the various bits & pieces will no longer be of any use to me!)

The first time I remember hearing about xenotransplantation back in 1984, although not, as I recall, using that specific name. It was the case of ‘Baby Faye’, who was born with hypoplastic left heart syndrome (the left side of the heart & the associated blood vessels are severely underdeveloped): doctors transplanted a baboon heart into the infant in an attempt to keep her alive until a suitable human donor became available. (However, this wasn’t the earliest case of xenotransplantation – it seems organ transplant  was first tried as far back as 1913, when doctors unsuccessfully transplanted a monkey kidney into a child whose kidneys had been damaged by mercury poisoning. Organs from baboons & other non-human primates have been used in transplants on several occasions, and it appears that frog skin was used in the late 1800s in treating patients needing skin grafts…)

Today the focus has shifted from primates to pigs. While the non-human primates are genetically closer to us, their organs are smaller – a baboon heart might do for a baby, but not an adult human! Nor can they be obtained in large numbers. Many primate species are under threat, or critically endangered. And many people would find it distasteful to consider killing other primates for the purpose of keeping humans alive.

Pigs, on the other hand, are closer to us in body size & mass, & are killed for food as it is, so it could be argued that taking organs for xenotransplantation would be less of a problem in ethical terms. Howver, pig organs are more likely to be rejected by their new host, & this has led to the idea of genetically engineering pigs so that they express human marker proteins on their cell membranes, instead of pig markers. This would reduce the likelihood of an extreme rejection reaction. And there are major concerns about the possibility of viral diseases, in particular, making the jump from pig to human via the new owner of the organs, although it’s been suggested that these could be reduced or eliminated in transgenic pigs.

But we also need to consider a range of other issues related to xenotransplantation. For example, people having Jewish or Muslum beliefs would probably find the idea of having pig tissues transplanted into them, quite abhorrent. Are there other cultural aversions to xenotransplants? What about the animals involved – do they suffer psychologically or physically before their deaths? Do we have the right to take their lives for this purpose? And the new ‘owner’ of the organ – would the presence of the xenotransplant alter them in some way? (There’s a Vatican document with a very thorough discussion of some of these ethical issues here.)

So, you can see that you’d got a lot to consider, if you chose this topic!

plant growth responses to touch Alison Campbell Sep 29

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Commenting on my last post about plant behaviour, Jim mentioned a paper by Marian Smith on plant responses to being touched or shaken. Unfortunately I couldn’t get the link to work, but I did a Google Scholar search on the name & topic & got this: Plant growth responses to touch – literally a ‘hands-on’ exercise! It’s in JSTOR so should be accessible for teachers & students interested in this paper, published in The American Biology Teacher (the link’s to the JSTOR backfiles of this journal).

Most people would be familiar with the rapid responses to touch shown by venus flytraps & mimosa plants (one being what you could describe as a ‘predatory’ response, & the other quite possibly an adaptive response that reduces damage from herbivory – fascinating stuff & I must write something more about it). But that would be it. However, it seems that most plants have a distinct, measurable growth-response to mechanical stimulation (Smith, 1991). This response tends to be a reduction in vertical growth in response to a range of environmental stresses: grazing would be the obvious one but there’s also wind (by itself or driving movement of one plant or plant part against another) & perhaps rain. If a plant is exposed to one of these stimuli & its stem grows shorter & thicker than in an undisturbed plant, this adaptive response would leave the plant less susceptible to future damage.

Smith’s paper goes on to describe how to investigate & analyse this growth response to touch - very interesting & also very doable, if you’re interested in having a go yourselves :-)

M.Smith (1991) Plant growth responses to touch – literally a ‘hands-on’ exercise! The American Biology Teacher 53 (2): 111-114 

what’s your favourite (transitional) fossil? Alison Campbell Sep 28

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A couple of weeks ago Brian Switek’s blog Laelaps included a post on transitional fossils (those things that some creationists will tell you simply don’t exist… ) Brian’s post was sparked by this story (OK, maybe the writer of was aiming for ‘balance’, but really!) & he suggested that others might like to emulate him & write something about their own favourite transitional fossil. The idea’s been simmering away in my mind since then.

Brian’s challenge required some pause for thought – what is my favourite transitional fossil? I do like the whales, but he beat me to it on that one. And then I thought, what about Diarthrognathus???

Diarthrognathus lived back in the Triassic (ie while the dinosaurs were the dominant land mammals) & was a ‘mammal-like reptile’ - as the name suggests, a reptile with some mammal-like features of its anatomy. These include things like the presence of different types of teeth in the mouth; development of a secondary bony palate that separates the nasal passage from the mouth – thus allowing you to breath with your mouth full!; legs that are more under the body rather than jutting out to the side like those of a lizard or crocodile;  and changes in the structure of lower jaw & jaw joint. I love the name Diarthrognathus, because it tells you what’s special about this beast: Diarthrognathus literally means ’double-jointed jaw’, & when you look at the skull & jaw, that’s just what you see.

But why is this so special? The answer has a lot to do with the evolution of jaws & ears – specifically, the bones of the middle ear.  The 3 bones of the mammalian middle ear (the ‘anvil’, ‘stirrup’, & ‘hammer’) have a long & interesting evolutionary history that begins with the bones of reptilian jaws (which in turn have a history of their own…). Anyway, when you compare the lower jaws of a mammal & a reptile, something stands out straight away: a mammal’s lower jaw is made up of just one bone, called the dentary (so named because the teeth are rooted in it). Reptiles have a dentary too, but there are several other bones in their jaws or associated with the jaw joint: the articular, angular, surangular, and coronoid, plus the quadrate where the jaw articulates with the skull. Please bear with the names, as the story’s easier to tell with them in it!  Turn to the ears, and while we have those 3 familiar little bones, in a reptile you’ll see only one, the stapes (stirrup).

Once developmental biologists started looking closely at embryonic development, they found something rather surprising. When a reptile embryo’s developing, two of its early head bones end up as the quadrate & articular bones of the jaw joint. But trace those same bones in a mammal embryo & you’ll find they become the malleus (hammer) & incus (anvil) of the middle ear, while the jaw articulation now involves the dentary in the jaw & squamosal bone of the skull. This leads to the conclusion that these 2 mammal ear bones are homologous to the quadrate & articular in a reptile’s jaw. And indeed, if you look at a series of increasingly mammal-like reptiles, you’ll find those 2 bones getting smaller & smaller & moving to the back of the jaw – in primitive mammals like Yanoconodon (as in platypus embryos today) they appear to have become detached from the jaw joint but remain attached to the jaw itself by a cartilagenous rod. (So you could – rightly! – say that there are a whole lot of transitional fossils in this story.)

What’s so neat about Diarthrognathus is that it retains both jaw joints, so that the lower jaw articulates with the skull at two points, rather than one: it has the reptilian articular & quadrate joing, & the mammalian dentary/squamosal version.  A lovely example of a transition if ever I saw one :-)

plants – much more than you expect Alison Campbell Sep 27

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One of the Biology Standards year 13 students study is called ‘Describe animal behaviour & plant responses’. Now, if ‘behaviour’ = response to a stimulus, then that’s really what plants are doing too. I guess it’s just hard to think that something (usually) green, (usually) fixed in place, & with no nerves or muscles is able to behave – but plants do, & some of their behaviour is really quite subtle. You’re probably familiar with plant responses to stimuli, including tropisms, circadian rhythms, & flowering in response to changes in photoperiod. But there’s more: not only are there plants that actively hunt, but plants can also communicate – with each other, & in some cases with animals as well.

For most plants herbivores represent a major, daily threat. Plants can respond directly to herbivore attack in a number of ways. (Years & years ago – while I was a school teacher in Palmerston North – I watched a program called The 300-million-year-old war, about the arms race between plants & animals. It was excellent, but I haven’t been able to find a copy of it since…) These responses aren’t limited to the production of toxic chemicals, but can also include a range of events – shown in the figure below - that limit food supply or reduce the availability of nutrients to the animal doing the damage. (Scientists are very interested in the processes involved because an understanding of what’s going on has obvious implications for agriculture.)

direct plant defense against herbivores.png

(Figure from Chen, 2008)

But it turns out that plants can also warn others of a herbivore’s attack – & this warning isn’t limited to members of the same species. In 2000 a series of experiments by Karban et al. demonstrated that undamaged plants respond to dues released by neighbours to induce higher levels of resistance against herbivores in nature. The researchers studied sagebrush and tomato plants, & looked first at how sagebrush responded to grazing by grasshoppers & cutworms, & also to simulated grazing (clipping the plants with scissors). They found that the plants released a volatile chemical, which they already knew could induce herbivore resistance in wild tobacco plants. The next step was to grow tobacco plants next to sagebrush plants (clipped and unclipped): tobacco growing next to clipped sagebrush produced more of a possible defensive chemical.

production of polyphenol oxidase in tobacco plants by clipped & unclipped sagebrush.png

Fig 2: Levels of polyphenol oxidase (PPO) activity for tobacco plants near clipped or unclipped sagebrush neighbours. (from Karban et al. 2000)

And – tellingly - tobacco plants near clipped sagebrush experienced greatly reduced levels of leaf damage by grasshoppers and cutworms… compared to unclipped controls.

damage in tobacco plants with clipped & unclipped neighbors.png

Fig 3: B Maximum proportion of leaves that were damaged by grasshoppers during each of three seasons on tobacco plants near clipped (Cl) or unclipped (Uncl) sagebrush. C Maximum proportion of leaves that were damaged by cutworms during the 1966 season on tobacco plants near clipped or unclipped sagebrush. (from Karban et al. 2000)

The tobacco plants seemed to gain more than immediate protection from grazing, as the term observed that tobacco plants with clipped sagebrush neighbours produced more flowers & seeds (which could translate into increased reproductive success) over a five-year period, although there was considerable variation from year to year. You have to wonder how widespread this sort of communication is. Karban & his colleagues didn’t see any evidence that tobacco plants communicated with each other, for example. And initial work on other species that normally grow near sagebrush suggested that one such species might gain herbivore resistance, but that two others showed no response at all.

And there’s more – plants under attack by herbivores can also use volatile organic chemicals (VOCs) to signal to predators, leading them to a source of food (those hungry little herbivores): daily predation rates [on herbivores] on plants releasing VOCs… were 4.9 to 7.5 times higher than those observed on control plants (Kessler & Baldwin, 2001). Intriguingly, in at least some cases Kessler & Baldwin found that in addition to attracting predators, some VOCs also reduced the rate at which other herbivores laid eggs on the plant.

Plants – much more than you expect :-)

M-S.Chen (2008) Inducible direct plant defense against insect herbivores: a review. Insect Science 15: 101-114. doi 10.111/j.1744-7917.2008.00190.x

R.Karban, I.T.Baldwin, K.J.Baxter, G.Laue & G.W.Felton (2000) Communication between plants: induced resistance in wild tobacco plants following clipping of neighbouring sagebrush. Oecologia 125: 66-71

A.Kessler & I.T.Baldwin (2001) Defensive function of herbivore-induced plant volatile emissions in nature. Science 291 (5511): 2141-2144.doi 10.1126/science.291.5511.2141

food & folate Alison Campbell Sep 26

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This is a re-posting of an article I wrote back in July. I thought I’d repost it here as I’ve been on a bit of a science/health/pseudoscience kick lately :-)

In the July 13 Herald was an article on the inclusion of folic acid (aka folate) in bread. This has hit the news recently because (among other things) bakers are concerned about the cost of adding this supplement to bread. (One figure that’s been bandied about is that someone would have to eat 11 slices of bread to get their recommended daily dose, but this surely a ‘straw man’ argument: while the NZ diet tends to be low in folate it’s not at zero - any amount of bread would supplement that low intake.)

There are a number of issues associated with this story, one being a perceived toxicity associated with folate & another being one of the ethics of mass medicalisation of a population.

But the one I want to touch on to begin with is related to this paragraph: On TV One’s Q&A programme, Ms Wilkinson faced criticism from Green MP Sue Kedgley, then presenter Paul Holmes, followed by all three members of the analysis panel. I’d assumed that this ‘analysis panel’ would include some input from someone who could give expert opinion on the science behind the folate-in-bread proposal. But from reading on, the panel members comprised a political scientist, a local-body politician, & a union representative. I suppose that’s to be expected in a program with an emphasis on political questions, but it’s still disappointing as it would have been useful to have that science input included.

So, why are we talking about adding folate/folic acid to bread anyway? The quick answer is, because we’re required to under an agreement with Australia. The underlying rationale is that a lack of folate in early pregnancy (typically before a woman may even be aware that she’s pregnant) is implicated in neural tube defects such as spina bifida. (Other environmental influences include insulin-dependent diabetes, & some types of medication.) In some estimates up to 90% of the population is folate-deficient to some degree, with a number of underlying reasons for this. Hence the former Health minister’s comment that the change would see four to 14 fewer neural tube defect-affected pregnancies a year - women would not get the recommended 400 microgram daily intake from bread alone, but any consumption would add to their existing intake.

Neural tube defects (NTDs) occur when the hollow neural tube -  which gives rise to both brain and nerve cord - doesn’t form properly, and include disorders such as spina bifida. It’s estimated that between 50 & 70% of NTDs could be prevented by increasing the amount of folate in a woman’s diet, especially during the period from 1 month prior to conception through to 3 months into the pregnancy. Obviously it’s not really possible to predict the date of conception, so ideally a woman would be ensuring her diet had the recommended level of folate from the time she began trying to conceive. Of course, things are complicated by the involvement of those other environmental factors, plus there may also be a genetic tendency to NTDs in some families. (Because of this one review recommends that – in developing countries anyway – iron-folate tablets could be provided to parents who already have a child with an NTD, rather than trying to ensure that all women take a supplement prior to & early in pregnancy.) A 2001 Cochrane review of the use of folate to prevent NTDs states that periconceptional folate supplementation has a strong protective effect against neural tube defects, and makes the further recommendation that information about folate should be made more widely available throughout the health and education systems. And the authors conclude that the benefits and risks of fortifying basic food stuffs, such as flour, with added folate remain unresolved.

So that’s the crunch point really, isn’t it? Just what are the benefits & risks, and the costs involved?

If the estimate of 4 – 14 fewer NTD-affected pregnancies each year is accurate, then that probably involves a reasonably substantial decrease of social and economic costs – the immediate & ongoing cost of supporting affected individuals and their families can be quite high. (For an individual with severe spina bifida, one estimate suggests a lifetime cost of around $500,000 dollars.) In many countries adding folate to flour is seen as the most cost-effective way of reducing NTDs. But is this sufficient reason for treating entire populations (‘mass medicalisation’? After all, at most only half the population is ever likely to become pregnant, & in New Zealand ‘only’ about 1 in 1000 pregnancies involves an NTD.

It does seem that folate may have wider benefits – low levels of folic acid in the diet may possibly be linked with a decline in the self-repair capacity of DNA (in relation to this they’ve also been linked to intestinal cancers in mice – but bear in mind my previous comments with regard from generalising from mice to men!). There’s also a suggestion that folate deficiency could be implicated in cardiovascular disease. In other words, it’s quite possible that supplementation of folate through measures like flour fortification would have benefits over and above those flowing from a reduction in NTDs.

What about the risks, then? Apparently high doses of folate (higher than the maximum recommended daily allowance) can mask the effects of vitamin B12 deficiency – in such cases the harmful effects of this particular deficiency would thus go untreated. And while one person quoted in the original press story was concerned that folate supplementation could be linked with an increased risk of cancer, I couldn’t find anything supporting this in an (admittedly quick) search of the literature. But in any case, I would have thought that if anythng, low folate levels would be more likely to be implicated in cancer risk.

In other words, this is another complex story – and one where the inclusion of a science-based viewpoint would have added some useful depth to the original article.

science blogging in new zealand Alison Campbell Sep 26

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I’ve been blogging for 2 years now & following other people’s blogs for rather longer than that. But I’ve only ever been aware of a few other NZ science bloggers; there’s so much material out there that unless you go looking for something specific, an individual blog can get lost in all the ‘noise’. But this is set to change next week, thanks to the Science Media Centre:

From the keyboards of scientists

Are scientists blogging in New Zealand? They sure are – but it is relatively tricky to find them.

That will change on September 30 when the Science Media Centre launches Sciblogs.co.nz, a blogging network bringing together some of the best science blogs in the country and launching a good few new ones.

Sciblogs will kick off with 25 bloggers from universities, CRIs and private research institutions covering everything from healthcare to climate change. Our bloggers know their stuff – they have two dozen PhDs between them and they aren’t afraid to tackle the big science-related issues affecting society.

Sciblogs will become an on-line hub for discussion of scientific topics and will grow to include other bloggers. if you would like to enquire about hosting a science blog on Sciblogs, contact the .

Sciblogs will be live on Wednesday September 30 and you will be able to keep tabs on our Scibloggers via RSS, email updates and by following Sciblogs on Twitter.

I’m looking forward to this with considerable excitement – it has the potential to raise the profile of science blogging in this country & make a whole lot of good writing much more widely available.

a rather strange decision Alison Campbell Sep 24

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A fellow blogger drew my attention to a recent decision by the Broadcasting Standards Authority.  It seems that Dr Shaun Holt, a medical doctor who appears regularly on TV1′s Breakfast show, has been slated by the BSA over some comments he made (several months back now) concerning chiropractic. The BSA found that the show – & by extension Dr Holt – had breached standards of accuracy, impartiality & objectiveness, & that the coverage was neither fair nor balanced.

Before I get on with the story - while the media like to present ‘both sides of a story’, sometimes there really aren’t two sides. Think of evolution & creationism, for example. One’s science, & one’s not, & a story about evolution most emphatically does not require ‘balance’ by adding a segment on creationism. The same could be said for vaccinations; contrary to what can be found on far too many websites, to date any number of well-designed scientific studies have found no link between autism (for example), so an item on vaccination does not need ‘balance’ by reporting claims that such a link exists…

OK, I’ll get off my soapbox…

Anyway, I can see where the ‘impartiality’ thing came from. Dr Holt has an interest in a firm that tests prescription medicines & CAM remedies, & because this wasn’t declared he could be said to have a conflict of interest in commenting unfavourably on chiropractic. But the BSA also decided that Dr Holt’s comments represented personal opinion & that he had made a number of strong, unqualified statements about what scientific research had to say about chiropractic treatment. Well, you can find a clip of the interview on YouTube (isn’t the internet wonderful?).

I watched it this evening. Dr Holt does indeed make some statements of opinion, but he also makes it clear that this is what he’s doing (what he would do for back pain, for example). But he also refers to scientific studies looking at the benefits & risks of chiropractic. (You can find reviews & protocols for meta-analyses of this work in the Cochrane system – here, for example. For more general commentary, Ben Goldacre has a fairly extensive set of links to such work here, as does David Colquhoun on his blog.) And TV1 gave equal time to a chiropractic spokesman, so it’s hard to see how a finding of ‘unfair’ could arise.

It would also have been nice to see the inclusion of a scientist on a panel that was making decisions about the scientific accuracy of what was being said, but alas! this was not the case. As I commented a little while back in relation to debate around adding folic acid to bread – for questions where questions of science are involved, we really should be hearing the voice of science in there somewhere.

science-based medicine vs the ‘natural’ kind Alison Campbell Sep 23

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This week a very dear friend of mine is having surgery for bowel cancer, having already gone through a course of comibined chemo/radiotherapy in preparation. When I was talking with her last week, she commented that she wasn’t looking forward to the operation, but the prospect of a few more years of reasonably comfortable life as a result of it was infinitely preferable to the alternative..

However, many people may well consider alternatives, particularly if they’re worried about the chemo/radiotherapy side of things. And yes, chemo can be really rough – hardly surprising as we’re talking cytotoxic (cell-killing) chemicals; the intention is that they kill off the tumour cells before they kill off everything else… And if you look, it’s fairly easy to find testimonials along the lines of ‘natural therapies cured my cancer’. But testimonial = anecdote, & anecdote =/= data; actual clinical trials of alternative therapies have been rare.

So I was interested to read Orac’s review of a trial that did just that – looked at the effectiveness of a ‘natural treatment’ (the Gonzalez protocol) for pancreatic cancer, an unpleasant & fast-progressing disease that’s just killed actor Patrick Swayze, compared to current best-practice chemotherapy. I’m not entirely sure what’s ‘natural’ about the regime Gonzalez patients are subjected to, and you’ll see why from what follows & from Orac’s very thorough coverage of the research. (I used this topic in my Schol tut the other day – it generated some really interesting discussion.)

When patients were invited into the file they were classified according to the stage of their cancer, their ‘performance’ status (things like blood chemistry & cell counts), and their nutritional status (well nourished or moderately malnourished vs severely malnourished). They were offered one of 2 treatments and could self-select which one they entered. One of those treatments was chemotherapy + palliative care, easing patients’ discomfort as much as possible. The other was the ‘nutritional’ arm using the Gonzalez protocol.

For 16 days, 4-hourly and at mealtimes, patients in the nutritional arm received oral pancreatic enzymes plus magnesium citrate plus papaya extract plus vitamins, minerals, trace elements & ‘animal gland extracts’ (whatever they are!) – well over 100 pills a day (hardly a ‘natural’ treatment!). They then had 5 ‘rest’ days, after which the whole thing began again. They also ate a vegetarian ‘metaboliser’ (??) diet that excluded red meat, chicken & white sugar. All that would be a hard regimen to stick to – but on top of it patients in this arm of the trial also received twice-daily coffee enemas (yes, coffee enemas!) plus various baths, ‘liver flushes’ and purgings.

The health status & quality of life of all patients was regularly assessed, & the two treatment arms were apparently fairly well matched (given the selection bias inherent in patient self-selection).

The research team ended up with a total of 55 patients in the trial, of whom 23 received chemo and the other 32, the ‘natural’ treatment. And their findings? Orac talks about them in depth, including a graph from the original paper that I’ve copied here as it really speaks for itself. (The SEER curve gives survival rates for the ‘average’ pancreatic cancer patient.)

Survivalgraph.jpg

Given that the patients in the nutritional arm of the trial did worse than the ‘average’ patient, and reported a much lower quality of life than those in the chemo arm, this is a sad outcome. Made worse when you realise that each downward step on the graph represents a death. But it’s not exactly unexpected, as this ‘treatment’ appears to be predicated on beliefs about what causes cancer & what can cure it rather than on any scientific evidence – a common theme for many complementary-&-alternative therapies. I know my friend has a different form of cancer, but gosh! am I glad she’s opted for the current gold standard of care!

critical thinking 101: reading news stories on science Alison Campbell Sep 22

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You’ve probably gathered by now that I get quite irritated by the way that some news reports portray science. But it’s not always easy to know what to look for, in terms of the tell-tale signs that let you know that all may not be as it first appears.

Fortunately the inestimable Ben Goldacre has just republished a guide on How to read stories about health and healthcare (this is a link to a pdf of the guide, written by Dr Alicia White) that applies equally well to other areas of science. I wish I’d read it before that Schol tutorial, as it would have made an excellent handout….

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