I will be travelling for a couple of days, heading down to Virginia where I will be giving a couple of lectures at the NASA Langley Research Center. The talk will be on the art and science of science communication. I will be discussing the many challenges faced by those trying to communicate science to the general public.
I will also be giving the talk on Tuesday March 1, at 7:30 pm, which is free and open to the public, at Virginia Air & Space Center in downtown Hampton, VA.
This should be a fun talk, so if you are in the area please come by.
Another 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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A jury has recently found for the plaintiff against the company Johnson and Johnson over the claim that their talc powder may have caused ovarian cancer in an Alabama woman who died of the cancer at 62. They awarded her family $72 million.
This story has had a great deal of attention because it raises two questions: what is the scientific evidence for a link between talc use and ovarian cancer, and how should the courts rule in such cases when the science is ambiguous?
Talc and Cancer
Concerns about the cancer causing effect of regular talc use stem from a time when talc contained asbestos. Since the 1970s, however, talc has been asbestos-free. Asbestos is clearly linked to cancer, but for the asbestos-free talc the link is not as clear.
There have been a number of large epidemiological studies looking at the association of talc use and risk of ovarian cancer, with some mixed results, but overall not impressive.
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For anyone active on social media it is almost a daily occurrence that a photo being passed around as if it were real is revealed as a fake. In fact, if you don’t want to look silly, it’s a great idea to Google before you share. A basic search is often all that is necessary, and if the photo is fake it is very likely that Snopes has you covered.
For the more intrepid, you can also use reverse-photo search websites. These will find matches to the photo you select, which can often reveal the original photo that was “photoshopped” in order to create that iconic representation of whatever ideology is being promoted.
Some people have a better eye for photo manipulation than others. Sometimes context is all you need – if the photo seems too perfect to be true, it probably is.
The task of sniffing out fake photos, however, (at least from a technical perspective) is getting more difficult. There are two basic ways to make a fake photo. The most common is to take a real photo and manipulate it. Just replace the words on that protest sign to say whatever dumb thing you want to mock.
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In 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 »
The farming systems we are putting in place now will need to feed the 9-10 billion people that will inhabit our planet in 2050. This is a huge challenge.
Many people speak about “sustainable farming,” which is a legitimate and important concept. Truly sustainable means that we need to track all of the inputs and outputs in the global food system and see that we can extrapolate that system indefinitely into the future.
One of the most, if not the most, important factor in sustainability is nitrogen. Plants need a lot of nitrogen to grow, and this is often the limiting factor in large-scale food production.
Thinking about where nitrogen ultimately comes from – the entire nitrogen cycle – is like thinking about where energy ultimately comes. It’s a very useful question to ask. For example, when people claim that they can run their car on water they are failing to ask this basic question. When you do you realize that the energy is not coming from burning the hydrogen and oxygen, but from whatever energy source you used the split the water into hydrogen and oxygen.
The same thought process applied to nitrogen is also illuminating. Continue Reading »
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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A 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.
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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Note: This post was originally published on June 28, 2010 on SkepticBlog. Although it is not about the same issues as the current NECSS controversy, I found the underlying principles relevant, and I still stand by the position outlined here.
One of the things that I love about the skeptical community is that it is a vibrant intellectual community that is not afraid to turn its critical eye inward. There is also sufficient diversity of background and perspective, superimposed upon a generally skeptical outlook, to provide some genuine conflict. While you won’t find many bigfoot believers in our ranks, we do run the spectrum from liberal to libertarian, militant atheist to Christian, scientist to artist, and politically correct to Penn Jillette.
The wringing of hands may at times seem tedious – but it’s all good. As long as we remember that at the end of the day we are all skeptics, a cultural minority looking to change the world.
Occasionally our diversity of approach does erupt into outright conflict, with the preferred medium usually being blogs. This happened recently in response to the appearance of Pamela Gay, an astronomer and co-host of the Astronomy Cast podcast with Fraser Cain, on my own podcast, the Skeptics’ Guide to the Universe. Pamela is a Christian, and on the SGU we have a tendency to be less than respectful of unscientific beliefs, including religious beliefs that wander into the arena of science.
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Ever since the theory of evolution won over the scientific community and became the established consensus scientific opinion, creationists have fought a cultural and legal war against it. They failed to win the scientific war, and they continue to do so.
This is not an uncommon tactic – if you lose in the arena of science, evidence, or facts, then fight in the arena of public opinion or regulation. Pseudoscientists are unfortunately savvy to this tactic.
In the case of evolution, creationists tried banning its teaching outright, which was eventually struck down as unconstitutional. So they demanded equal time, which was eventually struck down as unconstitutional (teaching religion as science in public schools). So they tried to disguise creationism as intelligent design, which didn’t fool anyone.
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