Archive for August, 2009

Aug 17 2009

H1N1 Vaccine and GBS

As most people have probably heard by now, we are in the midst of a pandemic – swine flu or H1N1. This is a strain of the Influenza A virus, which causes a severe respiratory infection. The virus evolves rapidly and each year new strains appear, causing the annual flu season which causes 30,000 deaths in the US and 500,000 world wide.  (The H and N refer to the two main proteins used to classify different strains of the virus – I wrote a more detailed summary here.)

Because the current pandemic is being caused by an H1N1 strain, the same strain that caused the 1918-1919 pandemic that killed millions, world health organizations are understandably concerned and they are tracking it carefully. There are also efforts underway to develop a vaccine. This further raises concerns because of the 1976 H1N1 pandemic – the vaccine given for that strain was linked to cases of Guillain-Barré Syndrome – GBS. Unfortunately, while the likely risk of GBS is much smaller than the risk from the flu itself, this risk has stoked the flames of fear-mongering about vaccines. This somewhat irresponsible article in the Daily Mail is a good example.


GBS is an autoimmune neurological disorder. It is a monophasic (one time process that gets worse then gets better) post-infectious illness. Essentially, an infection with a virus or bacteria triggers the immune system to have a second inflammatory response against myelin proteins. Myelin is the insulation around nerves – the inflammation inhibits nerve conduction, damages the myelin, and when severe can damage the underlying nerve fiber itself. This results in weakness, numbness, and autonomic dysfunction. The weakness, when very severe, can inhibit breathing resulting in the need for mechanical ventilation. Right now the greatest risk from the disease is the autonomic dysfunction which can cause a severe drop in blood pressure, among other symptoms.

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71 responses so far

Aug 14 2009

The Worried and Wonky Well

A skeptical theme that crops up very frequently is the fact that there is a huge disconnect between popular beliefs and the findings of science. There is a tendency for people to overestimate their own knowledge even when they have no basis for their confidence (even skeptics – we all do this). Often this amounts to just making up answers because they feel right and then assuming they are correct. We all do this – believers and skeptics alike. This is the default mode of human thinking. It takes discipline to insert the critical thinking filter – “is this really true? what does the evidence actually say?”

The specific topic at hand is attitudes toward so-called complementary and alternative medicine (CAM) – how popular is it, and what is the basis for its popularity? I have dealt before with the former question. Here’s the summary: most surveys that site huge numbers of people using CAM are grossly inflating the numbers by including things such as exercise, prayer, or taking a multivitamin. I exercise, so by some measures I am a CAM user. This, of course, reflects the confusion caused by the dubious category of CAM itself – it is a pseudo-category, containing a wide variety of modalities, some mutually exclusive, with very fuzzy boundaries.

It is more meaningful to consider individual claims and practices, and to use somewhat tighter categories (such as energy-medicine). If we consider the “hard-core” CAM practices – like homeopathy, acupuncture, and energy medicine – we find that their use is still in the tiny minority – single digits. And these numbers are not significantly changing over time. The popularity of CAM is overblown.

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21 responses so far

Aug 13 2009

Vision and How the Brain Organizes Itself

Published by under Neuroscience

Knowledge about brain organization and development is rapidly evolving, partly due to new tools we have for research, such as various MRI techniques. One type of question being investigated is the degree to which brain organization is pre-programmed in the genes vs a result of the process of development.

We know that both processes are involved. Human brains are all grossly the same – I have looked at hundreds of MRI scans of patients and they are all pretty much laid out the same way. Neurologists get very good at predicting exactly where a lesion will be in the brain based upon a patient’s symptoms and exam. This ability to localize a lesion is based upon the assumption that all brains are organized the same, and this assumption turns out to be almost always correct, at least to a level of precision required for a clinical assessment. (There are known variations in terms of which side of the brain will house certain specific functions – for example most people are dominant for language in the left hemisphere, but some left-handed people have language in the right hemisphere.) This suggests that genetics plays a dominant role in determining the large-scale structure of the brain.

But neuroscience researchers often operate at a much finer level of detail in terms of neuroanatomy, often dealing with the micro-structure of the brain. And the question remains, at fine levels of detail, how much of the brain’s structure is pre-determined by genetics, how much results from the process of development, and how much is plastic (determined by later use)?

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9 responses so far

Aug 11 2009

End-of-Life Decision Making

Much attention is being paid recently to the culture of medicine in America. Health care reform is triggering a much needed (although certainly not new) discussion about many aspects of health care, trying to find solutions to a very complex problem, and even just trying to define the problem. One small aspect of this broad discussion, one part of the culture of medicine in America, is the conflict between patient choice and cost-effective medicine.

I am a strong advocate of patient choice – long gone are the paternalistic days of doctors dictating care to passive patients or their surrogates. But part of the problem with rising health care costs is the culture of medicine – from the doctor and patient side. And therefore any attempts at making medicine more cost effective are going to require a change in that culture. I believe the preferred method is through education of best practices, but expectations may need to be altered as well.

This conflict between choice and standards is perhaps most emotional when it comes to end-of-life decisions, but this may also be where significant savings can be made without compromising quality of care.

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21 responses so far

Aug 10 2009

Botanicals and Menopause – No Effect

Black Cohosh is a common herbal or botanical treatment for the hot flashes and other symptoms of menopause. This treatment appeals to women who want a more natural or gentle approach to their symptoms. Unfortunately, as the latest research shows, it doesn’t work.

Interest in herbal medicine has increased in the last 15 years as a response to weakened regulation and a successful marketing strategy by the supplement industry in the context of a cultural phenomenon of changing attitudes toward medicine. This has mainly led to, however, confusion about what herbal therapy really is. Most people I talk to think of herbal treatments as natural supplements – but they are not supplements and being “natural” is irrelevant. In fact it is much more accurate to think of them as unpurified drugs.

Botanical research is a legitimate and useful branch of pharmacology, with its own experts. The plant kingdom is a vast chemistry laboratory, specializing in chemicals that have some effect on other living things. The process of experimentation through evolution is slow, but has had hundreds of millions of years to operate. As a result we are surrounded by plant-based chemicals – some benign, most toxic, and a few with pharmacological properties we can exploit to our advantage if we’re careful.

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16 responses so far

Aug 07 2009

Virtual You

New research builds upon the growing body of research into how our brains give us a sense that we are inside our bodies. That is one of the brain’s functions that we take for granted – and do not even realize that it is a function of the brain or that it is necessary – until it is not functioning. When that happens we have an out-of-body experience (OBE).

Prior to modern neuroscience, OBEs were interpreted as mystical or spiritual experiences. In many cultures they were provoked by drugs during spiritual rituals. They have also been reported during certain dream states and in near-death experiences.

Unless one is a neuroscientist or has a keen interest in how the brain works, we tend to think of our mental selves as an integrated whole and not as a collection of independent functions – the latter is more close to the truth. Our brains are more like committees with many different parts carrying out specific functions – some conscious, some unconscious. But since we are our brains we are only aware of the net effect of that part of our brain function that produces our conscious awareness and attention. We are not aware of the bickering committee operating behind the scenes, and therefore we are not aware of all the subconscious tasks being carried out by individual components of our brains.

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15 responses so far

Aug 06 2009

New Scientist on Miracles

Published by under Logic/Philosophy

Philosopher Hugh McLachlan has written what in my opinion is a rather incoherent article on miracles for the New Scientist. He takes on David Hume and Richard Dawkins for taking the premises that miracles, by definition, violate natural law and that such events are used by the religious to support their faith.

McLachlan writes:

I would argue that, by definition, “laws of nature” are universal laws of the form “if A, then B”, or “all As are Bs”. Logically, they cannot be violated or transgressed, not even by God. If, even on one occasion, for whatever reason, there was an A without a B, then it would not be true to say “if A, then B”. What had been thought of as a natural law would in fact not be one.

He argues, therefore, that a “miracle” cannot be defined as an event that violates a law of nature, for that would be a violation of logic, which cannot occur. This is a circular and ultimately useless argument, however. Hume and Dawkins are defining a miracle as an occurrence that appears to violate the known laws of nature. McLachlan says this cannot happen because then the violated law would not be a law.

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44 responses so far

Aug 05 2009

Ghost Photo

Published by under Paranormal

3837925bThese stories crop up every now and then – someone looking through recent photos notices something odd, perhaps something that was not noticed when the picture was taken. Many people will shrug off such anomalies – weird stuff happens on pictures all the time. However, those with a certain inclination may jump on a paranormal explanation, which most likely means the photo will be presented as evidence for ghosts.

And sometimes the local news will pick up such a story, because they are suckers for that sort of thing.

The latest ghost photo flap deals with this picture (click to enlarge). Look in the upper left hand corner and you will see what appears to be the face of an old woman.

The news story is presenting this as “ghost or hoax” – a silly false dichotomy. Some of the comments to the story are buying this false dichotomy, give the old argument, “why would they lie?” – so therefore, the only other option, is that it must be a ghost.

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21 responses so far

Aug 04 2009

The Next Electric Car

Published by under Technology

I have been following this technology and occasionally posting about it here, so I thought I would mention that Nissan has announced their new fully electric car line – Leaf. They expect it will roll out in 2010, but perhaps not fully until 2012.

Of course, I was interested in the specs. These were interestingly difficult to come by – I had to dig pretty deep on the company’s website, and the vital stats were not in the press release. The Leaf is powered by a lithium-ion battery, like the Chevy Volt. However, the Volt still retains a small gas engine to recharge the battery and extend its range, while the Leaf does not. Previous electric cars (like the GM car featured in the movie, Who Killed the Electric Car) used a Nickel-Metal Hydride battery with a much shorter range.

Nissan claims a maximum speed of 90mph. I suspect we won’t know how peppy it is until consumers are driving in ones that have come off the assembly line. It is a 5-door sedan that seats 5 – Nissan specifically wanted an ordinary and not futuristic-looking car, which was probably a good idea. They want the technology to seem real and practical, not a futuristic novelty.

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20 responses so far

Aug 03 2009

Memes and the Singularity

Published by under Skepticism

Susan Blackmore is a memeticist – that is she studies memes. The term “meme” was coined by Richard Dawkins in his 1976 book, The Selfish Gene, and refers to a unit of cultural evolution, just as a gene is a unit of biological evolution. Genes and memes are both replicators – information subject to evolutionary processes. Now Blackmore is arguing that we are on the brink of developing a new third replicator – a technological one.

The idea is interesting, and I wonder if Blackmore is aware of the degree to which her ideas mirror those of Ray Kurzweil and his “singularity”. For background, Kurzweil argues that any system that encodes information is likely to form a positive feedback loop  – information builds on information in an accelerating process.

Actually, this goes back even before life arose on earth. The prebiotic earth saw chemical evolution, which is what likely led to the first self-replicating systems that can be said to be alive. At this time we can only know about the prebiotic earth by positing plausible prebiotic environments and plausible chemical pathways that could have led to RNA (the current theory), and then how RNA could have led to the first cells and life. This process of chemical evolution was relatively slow and with limited potential in terms of what it could create.

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11 responses so far

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