Henrietta Lacks' Immortal Cells

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Once there was a woman whose cells were immortal. What does this mean? Today, these cells have multiplied in laboratories worldwide to the point that, if you were to weigh all the cells that currently exist, they’d weigh about 50 million metric tons—about as much as 100 Empire State Buildings. So who was this woman, and why are scientists keeping her cells supplied with fresh nutrients so they can live on?

The woman was Henrietta Lacks, and her immortal cells—dubbed "HeLa"—have been essential in many of the great scientific discoveries of our time: curing polio; gene mapping; learning how cells work; developing drugs to treat cancer, herpes, leukemia, influenza, hemophilia, Parkinson’s disease, AIDS … and the list goes on and on (and on). If it deals with the human body and has been studied by scientists, odds are those scientists needed and used Lacks' cells somewhere along the way. HeLa cells were even sent up to space on an unmanned satellite to determine whether or not human tissue could survive in zero gravity.

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Lacks was an impoverished black woman who died on October 4, 1951 of cervical cancer at just 31 years old. During her cancer treatment, a doctor at Johns Hopkins took a sample of her tumor without her knowledge or consent and sent it over to a colleague of his, Dr. George Gey, who had been trying for 20 years, unsuccessfully, to grow human tissues from cultures. A lab assistant there, Mary Kubicek, discovered that Henrietta’s cells, unlike normal human cells, could live and replicate outside the body.

Go to just about any cell culture lab in the world and you’ll find billions of HeLa cells stored there. In contrast to normal human cells, which will die after a few replications, Lacks' cells can live and replicate just fine outside of the human body (which is also unique among humans). Give her cells the nutrients they need to survive, and they will apparently live and replicate along forever, almost 60 years and counting since the first culture was taken. They can be frozen for literally decades and, when thawed, they'll go right on replicating.

Before her cells were discovered and widely cultured, it was nearly impossible for scientists to reliably experiment on human cells and get meaningful results. Cell cultures that scientists were studying would weaken and die very quickly outside the human body. Lacks' cells gave scientists, for the first time, a “standard” that they could use to test things on. HeLa cells can survive being shipped in the mail just fine, so scientists across the globe can use the same standard to test against.

Lacks died of uremic poisoning, in the segregated hospital ward for blacks, about 8 months after being diagnosed with cervical cancer, never knowing that her cells would become one of the most vital tools in modern medicine and would spawn a multi-billion dollar industry. She was survived by her husband and five children; the family lived in poverty for most of their lives, and didn't find out about the fate of Lacks' incredible cells until years later.

If you'd like to know more about Henrietta Lacks and her immortal cells, check out The Immortal Life of Henrietta Lacks by Rebecca Skloot.

Here's What Actually Happens When You're Electrocuted

Benjamin Franklin was a genius, but not so smart when it came to safely handling electricity, according to legend. As SciShow explains in its latest video, varying degrees of electric current passing through the body can result in burns, seizures, cessation of breathing, and even a stopped heart. Our skin is pretty good at resisting electric current, but its protective properties are diminished when it gets wet—so if Franklin actually conducted his famous kite-and-key experiment in the pouring rain, he was essentially flirting with death.

That's right, death: Had Franklin actually been electrocuted, he wouldn't have had only sparks radiating from his body and fried hair. The difference between experiencing an electric shock and an electrocution depends on the amount of current involved, the voltage (the difference in the electrical potential that's driving the current), and your body's resistance to the current. Once the line is crossed, the fallout isn't pretty, which you can thankfully learn about secondhand by watching the video below.

Big Questions
Does Einstein's Theory of Relativity Imply That Interstellar Space Travel is Impossible?

Does Einstein's theory of relativity imply that interstellar space travel is impossible?

Paul Mainwood:

The opposite. It makes interstellar travel possible—or at least possible within human lifetimes.

The reason is acceleration. Humans are fairly puny creatures, and we can’t stand much acceleration. Impose much more than 1 g of acceleration onto a human for an extended period of time, and we will experience all kinds of health problems. (Impose much more than 10 g and these health problems will include immediate unconsciousness and a rapid death.)

To travel anywhere significant, we need to accelerate up to your travel speed, and then decelerate again at the other end. If we’re limited to, say, 1.5 g for extended periods, then in a non-relativistic, Newtonian world, this gives us a major problem: Everyone’s going to die before we get there. The only way of getting the time down is to apply stronger accelerations, so we need to send robots, or at least something much tougher than we delicate bags of mostly water.

But relativity helps a lot. As soon as we get anywhere near the speed of light, then the local time on the spaceship dilates, and we can get to places in much less (spaceship) time than it would take in a Newtonian universe. (Or, looking at it from the point of view of someone on the spaceship: they will see the distances contract as they accelerate up to near light-speed—the effect is the same, they will get there quicker.)

Here’s a quick table I knocked together on the assumption that we can’t accelerate any faster than 1.5 g. We accelerate up at that rate for half the journey, and then decelerate at the same rate in the second half to stop just beside wherever we are visiting.

You can see that to get to destinations much beyond 50 light years away, we are receiving massive advantages from relativity. And beyond 1000 light years, it’s only thanks to relativistic effects that we’re getting there within a human lifetime.

Indeed, if we continue the table, we’ll find that we can get across the entire visible universe (47 billion light-years or so) within a human lifetime (28 years or so) by exploiting relativistic effects.

So, by using relativity, it seems we can get anywhere we like!

Well ... not quite.

Two problems.

First, the effect is only available to the travelers. The Earth times will be much much longer. (Rough rule to obtain the Earth-time for a return journey [is to] double the number of light years in the table and add 0.25 to get the time in years). So if they return, they will find many thousand years have elapsed on earth: their families will live and die without them. So, even we did send explorers, we on Earth would never find out what they had discovered. Though perhaps for some explorers, even this would be a positive: “Take a trip to Betelgeuse! For only an 18 year round-trip, you get an interstellar adventure and a bonus: time-travel to 1300 years in the Earth’s future!”

Second, a more immediate and practical problem: The amount of energy it takes to accelerate something up to the relativistic speeds we are using here is—quite literally—astronomical. Taking the journey to the Crab Nebula as an example, we’d need to provide about 7 x 1020 J of kinetic energy per kilogram of spaceship to get up to the top speed we’re using.

That is a lot. But it’s available: the Sun puts out 3X1026 W, so in theory, you’d only need a few seconds of Solar output (plus a Dyson Sphere) to collect enough energy to get a reasonably sized ship up to that speed. This also assumes you can transfer this energy to the ship without increasing its mass: e.g., via a laser anchored to a large planet or star; if our ship needs to carry its chemical or matter/anti-matter fuel and accelerate that too, then you run into the “tyranny of the rocket equation” and we’re lost. Many orders of magnitude more fuel will be needed.

But I’m just going to airily treat all that as an engineering issue (albeit one far beyond anything we can attack with currently imaginable technology). Assuming we can get our spaceships up to those speeds, we can see how relativity helps interstellar travel. Counter-intuitive, but true.

This post originally appeared on Quora. Click here to view.


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