Friday, August 18, 2017

Classifying Cells and Cell Types

How do we describe the types of cells that comprise the human body? Pick any textbook of human biology and you'll find that cells are generally described as belonging to one of four types of tissue (nervous, muscle, connective, and epithelial) based on their broad function. At the next level of complexity, cells within a tissue are further described by their location and more specialized function (smooth muscle surrounding blood vessels; skeletal muscle attached to bones; cardiac muscle in the heart). Beyond these rather broad descriptions, many subtleties between cells are probably lost for lack of a way to measure or define them.

Some scientists think there may be a better way to identify and categorize cells. That's because what actually determines the differences between cells, both in terms of form and function, is the different proteins that they express. Those proteins are determined by the molecules of RNA that are present within the cell, which in turn are determined by which of the cell's genes are active. So to get a more refined measure of a cell's type and its true activity, it would make sense to measure not its shape, its location, or its broad function, but instead to determine which RNA molecules are present in the cell.

A group of enterprising scientists is attempting to do just that, according to an article in The New York Times. They've started with an organism (a type of worm) that has fewer than 1,000 cells. If all goes well, some day we may know a lot more about the incredible complexity of our various cells. And we may have to rethink how we classify cells and describe the relationships between them.

Saturday, August 12, 2017

A New Antibiotic to Combat Antibiotic-Resistant Gonorrhea

Scientists have discovered an entirely new antibiotic that may be useful against strains of gonorrhea bacteria that are resistant to most current antibiotics. It's called closthioamide. It was discovered in 2010, but it has taken until now to learn how to produce it in large enough quantities to be useful.

To date, closthioamide has only been tested in the laboratory on samples of gonorrhea bacteria known to be resistant to most antibiotics. It worked on nearly all of the samples. The next steps will be to try it on animals (to demonstrate its safety) and eventually on humans (to reaffirm its safety and prove that it can cure gonorrhea infections in patients). If all goes well, some day closthioamide may be a new weapon in the arsenal against gonorrhea and other bacterial infections - at least until the bacteria develop resistance to it!

Saturday, August 5, 2017

Prevalence of CTE in NFL Football Players

Repetitive blows to the head can lead to a debilitating chronic brain disorder called chronic traumatic encephalopathy (CTE) later in life. CTE is of particular concern to football players, boxers, and even soccer players. How common is CTE among certain athlete groups, and should we be concerned?

Of course we should be concerned. We would be remiss if we didn't try to find out how and why it is happening to our athletes, and how to prevent it in the future. But we should not scare people needlessly with sensationalist headlines. Take, for example, a CNN news headline: "Study: CTE in 99% of dead NFL players". Or this one in the Daily Mail (a British journal): "Biggest Ever NFL brain study diagnoses CTE in 99% of deceased players' brains". Read more closely and you find that the correct statement is that CTE was found in 99% of deceased ex-NFL players whose brains were donated to scientific research by their relatives (my emphasis). It's not a group that is representative of all deceased NFL players, by any means. It is likely that many if not most of these relatives donated their loved-ones' brains because they already suspected the presence of CTE based on their loved ones' behavioral symptoms while still alive. A definitive diagnosis of CTE can only be made at autopsy. CTE generally isn't looked for in a deceased player without symptoms of CTE, so in fact we really don't know how prevalent it is.

Clearly, CTE is present in many ex-NFL players, and its time to do something about it. The numbers may turn out to be higher than initially thought, and that would be sad. But there's no evidence that it's as prevalent as 99%, at least at the moment. Let's approach this problem with level heads and open minds.

Wednesday, August 2, 2017

Some Sunscreens Slow the Progression of MS in Mice

Sometimes it's better to be lucky than good. Quite by accident, researchers have discovered that ingredients found in Coppertone and other sunscreens may be able to slow the progression of multiple sclerosis (MS). The researchers were studying the known protective effect of UV light on the development of multiple sclerosis (MS) in mice prone to the disease. In the course of these experiments they administered various sunscreens to mice without exposing them to UV light, as controls. Surprisingly, several of the sunscreens slowed the development of MS all on their own. Coppertone was particularly effective. Further tests revealed that two ingredients in particular, homosalate and octisalate, were responsible.

These findings sound like a real breakthrough, but realistically they just represent interesting observations that are worthy of being pursued. A lot more work will need to be done before we will know how these compounds exert their protective effect in mice, and whether they ultimately might be useful in treating MS in humans. The findings also highlight the importance of doing proper controls, because in this case the most interesting findings came from a group of animals receiving sunscreen alone, as controls for mice exposed to UV light and receiving sunscreen. No one expected sunscreen to have an effect on its own.

You can read the abstract of the research paper here. Unfortunately, you'll need access to the Proceedings of the National Academy of Sciences journal in your library to read the entire text. Or you can read a news article about the paper in The Economist.