Archive for the 'Science and Medicine' Category

Mar 15 2016

Cryotherapy – Basic vs Clinical Science

RoganOn a recent episode of the Joe Rogan Experience (starting at the 2:10 mark), Rogan discusses an article I wrote previously on Science-Based Medicine about whole body cryotherapy (WBC). Rogan did not like my article, which he characterized as “poorly done and poorly researched.” He was discussing the article and WBC in general with his guest, Dr. Rhonda Patrick.

What this discussion revealed, in my opinion, is a significant lack of understanding of the roles of basic science research vs clinical research. Before I get to the discussion, here is a quick review of WBC.

Whole Body Cryotherapy

WBC involves exposing the whole body to extremely low temperatures, -200 to -240 degree F temperatures (-125 to -150 C) for 1.5-3 minutes. There are chambers where the head sticks out the top, and there are chambers that you step into entirely.

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14 responses so far

Mar 10 2016

A Raw Milk Fiasco

raw-milkLegislators in West Virginia passed a law legalizing the drinking of raw milk (but not the sale or distribution). Some of them drank raw milk to celebrate, and later came down sick with stomach symptoms.

This is one of those perfectly ironic stories that the internet loves. However, the lawmakers in question are denying that the milk is to blame. Instead they blame a stomach virus that has been going around their capital. A definitive answer is not yet available.

While the story is funny, it is irrelevant to the real question – is raw milk safe, and are there any health benefits beyond pasteurized milk? The answer to both questions is no.

Risks of Raw Milk Continue Reading »

29 responses so far

Mar 07 2016

Wind Turbine Controversy

windturbines1Wind energy is on the rise as a clean renewable form of energy. It has many advantages – no carbon emissions (beyond construction of the turbines themselves), no pollution, no waste, and no use of limited resources. The three often-cited downsides of wind power are that the turbines can be an eyesore, they may cause symptoms in susceptible individuals (so-called wind turbine syndrome, WTS), and they can be a hazard to flying creatures.

The eyesore issue for me is not a big issue. I actually think wind turbines dotting the horizon look pretty, but even if you disagree that is a small price to pay for the advantages.

I’m a bird watcher, and so am very sensitive to the issue of protecting bird diversity. I wrote about this issue previously.

A review of scientific studies of the number of bird deaths caused by wind turbines estimates that  140,000 and 328,000 bird deaths are caused each year. This may seem like a lot, but a study published in 2013 concluded that domestic cats kill between 1.3 and 4.0 billion birds each year. Further, an estimated 100 million birds are killed each year by flying into windows.

This makes the number of birds killed by wind turbines a round-off error. Continue Reading »

27 responses so far

Feb 26 2016

Mitochondrial Replacement Therapies

mitochondriaAnother innovative medical technology is on the brink of being applied to actual patients, and it is spawning the typical discussion about the ethics of altering human biology. I think this will likely take the usual course.

The technology is mitochondrial replacement therapies (MRTs). Mitochondria are organelles inside every cell. They are the power plants of cells, burning fuel with oxygen to create ATP, which are molecules that provide energy for all the processes of life.

Interestingly, mitochondria probably derived from independent cells that evolved a symbiotic relationship with eukaryotic cells. They are like bacteria living inside each cell with a specialized function of making ATP.

Mitochondria still retain some of their own DNA, which is partly how we know they were once independent organisms. Mitochondria contain 17,000 base pairs and just 37 genes (compared to 20,000 genes in human nuclear DNA). Over millions of years of evolution they have also outsourced some of their DNA to the nuclear DNA of cells, but also still retain some of their own DNA. Not only does this mitochondrial DNA affect the functioning of the mitochondria itself, it has implications for overall cell function through its interaction with nuclear DNA.

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18 responses so far

Feb 22 2016

The Evidence Says – Homeopathy Does Not Work

airguitarIn a recent blog post for the BMJ, Paul Glasziou wrote about the recent Australian review of homeopathic remedies of which he was head:

…I lost interest after looking at the 57 systematic reviews (on 68 conditions) which contained 176 individual studies and finding no discernible convincing effects beyond placebo.

He is not the first person to look at the totality of clinical evidence for homeopathy and find it wanting. Glasziou was chair of the working party that produced the 2015 NHMRC report on homeopathy, which concluded:

Based on the assessment of the evidence of effectiveness of homeopathy, NHMRC concludes that there are no health conditions for which there is reliable evidence that homeopathy is effective.

So, after more than two centuries, and thousands of studies in total, no homeopathic treatment has crossed over the line of what would generally be considered sufficient evidence to prove that it works. That is very telling. I liken the evidence to other dubious claims, such as ESP. After a century of research and thousands of studies there is no clear evidence that ESP is real.

For both homeopathy and ESP there is a great deal of noise, but no clear signal. There are many flawed or small studies, but no repeatable high quality studies. Continue Reading »

23 responses so far

Feb 18 2016

Practicing Medicine Without a License

fake-diploma1

After four years of rigorous study in medical school, which includes grueling class work and then clinical rotations in which you may work 80 hours a week, followed by killer exams to demonstrate you have mastered a vast body of knowledge, you are not yet competent to practice medicine. Those four years only prepare you for your real training as an intern and then resident, another three or more years.

Even then, newly minted attendings who are supposed to be able to practice independently may appreciate having access to more experienced colleagues.

Further, as you accrue invaluable experience over time your fund of knowledge can actual degrade, because the science of medicine is quickly advancing under your feet. It is a struggle to keep up, which is partly why so many physicians specialize.

This is why one of the most important lessons we teach medical students and doctors in training is to have a very good sense of your own limitations. You need to have some sense of how deep any particular specialty is, so that you can gauge your own relative ignorance. The bottom line is – don’t practice out of your depth.

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24 responses so far

Feb 16 2016

3D Printing Body Parts

3dprintbodypartsA new study published recently in Nature Biotechnology reports a significant advance in the technology of 3D printing body parts designed to be implanted in human patients. This is an exciting technology, but we are still in the early phase of development.

3D Bioprinting

Printing body parts is one approach to creating tissue and organs to replace those lost, damaged, or diseased. This is a top down approach, directly constructing the body part. The other approach is bottom up – growing a body part from stem cells.

The 3D printing technology itself is more than adequate for this task. That is in no way the limiting factor – we can create objects of precise size and shape sufficient for implantation. We can, for example, make an exact replacement for a missing piece of bone.

The biggest limiting factor in creating body parts of “clinically relevant size, shape, and structural integrity,” is keeping the cells alive. The problem is when we print body parts we are printing the skin, muscles, bone, and cartilage, but not nerves or blood vessels. Without blood vessels, the only way for the cells to get oxygen and nutrients is through direct diffusion, which has a limit of 100-200 micrometers. This is too small to be clinically useful.

This was the specific advance reported in the recent study. The researcher incorporated pores or microchannels into the printed tissue, allowing for far greater diffusion. The tissue became more like a sponge.  The bottom line is that this technique worked, they were able to create cartilage, for example, of 3.2 cm x 1.6 cm x 0.9 cm which survived in vivo without necrosis.

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4 responses so far

Jan 26 2016

The Zika Virus

aedes mosquitoThe World Health Organization (WHO) and Center for Disease Control (CDC) are warning about yet another virus epidemic, the Zika virus. It may seem like such warnings are overblown, but they do need to be taken seriously.

Zika Virus

The Zika virus (Flaviviridae, an arbovirus) is spread through Aedes mosquito bites, the same mosquitoes that also spread Dengue fever. The infections themselves are usually mild, causing fever, rash, joint pain, and conjunctivitis. Many of those infected may even have a subclinical infection, meaning they do not notice any symptoms.

However, the infection can have complications. There is one case report of Guillain-Barre Syndrome (GBS) following a Zika infection. GBS causes inflammation of the lining of nerves resulting primarily in weakness with variable recovery. This does not appear to be a huge risk, but something to monitor.

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13 responses so far

Jan 19 2016

Charlie Sheen’s HIV Quack

charlie-sheen-dr-oz-show-regular-guest-ppCharlie Sheen is HIV positive. As was revealed on the Dr. Oz show, when diagnosed his viral load was 4.4 million. After six months of the a standard anti-HIV cocktail his viral loads were undetectable.

This does not mean he is HIV negative or free of this virus. As part of the viral life-cycle it goes into hiding inside of cells. It is undetectable while hiding, and also cannot be eradicated by medications. This is a major challenge to curing HIV, or even pushing the efficacy of our current treatments further. Researchers are looking into ways to force the virus out of hiding so that anti-retroviral medications can go to work.

With current anti-HIV treatment someone who is HIV positive can expect to live an almost normal life expectancy free of any major complications of the disease and will not go on to develop AIDS from the virus. The big challenge now is to get this modern medicine to those who are HIV positive in the third world, or to those who cannot afford it.

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221 responses so far

Dec 15 2015

Contaminants Found in 92% of TCM Herbal Products

Chinese-herbs4A new study out of Australia looked at 26 different Traditional Chinese Medicine (TCM) products purchased from stores. They performed three types of analysis: heavy metal screening, toxicological analysis, and DNA sequencing. They found that 92% of the products tested had at least one type of contaminant.

This adds to a growing list of studies and revelations about how poorly the supplement industry is regulated, and raises further concerns about the overall quality of herbal and supplement products.

A 2008 study found that about 20% of ayurvedic herbal products contained heavy metal contamination, often at levels high enough to be toxic.  Continue Reading »

34 responses so far

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