Not one cell in your body remains from what was there seven years ago

So the question is, what is invisible? There is more of it than you think, actually. Everything, I would say. Everything that matters except every thing and except matter....

So, we can see the stars and the planets, but we can't see what holds them apart or what draws them together. With matter, as with people, we see only the skin of things. We can't see into the engine room. We can't see what makes people tick, at least not without difficulty. And the closer we look at anything, the more it disappears. In fact, if you look really closely at stuff, if you look at the basic substructure of matter, there isn't anything there. Electrons disappear in a kind of fuzz, and there is only energy. And you can't see energy….

Another thing we can't see is the human genome. And this is increasingly peculiar, because about 20 years ago, when they started delving into the genome, they thought it would probably contain around 100,000 genes. Geneticists will know this, but every year since, it's been revised downwards. We now think there are likely to be only just over 20,000 genes in the human genome. This is extraordinary. Because rice -- get this -- rice is known to have 38 thousand genes. Potatoes, potatoes have 48 chromosomes. Do you know that? Two more than people, and the same as a gorilla….

Time, nobody can see time. I don't know if you know this. Modern physics, there is a big movement in modern physics to decide that time doesn't really exist, because it's too inconvenient for the figures….

Another thing you can't see is the grid on which we hang. This is fascinating. You probably know, some of you, that cells are continually renewed. You can see it in skin and this kind of stuff. Skin flakes off, hairs grow, nails, that kind of stuff. But every cell in your body is replaced at some point. Taste buds, every 10 days or so. Livers and internal organs sort of take a bit longer. A spine takes several years. But at the end of seven years, not one cell in your body remains from what was there seven years ago. The question is, who, then, are we? What are we? What is this thing that we hang on, that is actually us?...

Anyway, so the biggest thing that's invisible to us is what we don't know. It is incredible how little we know. Thomas Edison once said, "We don't know one percent of one millionth about anything."…

But the point, what I've got it down to, is there are only two questions really worth asking. "Why are we here?" and "What should we do about it while we are?”  

 [Source: John Lloyd’s TEDtalk “Inventories the Invisible”  

 http://www.ted.com/talks/john_lloyd_inventories_the_invisible.html

Animated TedED version

http://ed.ted.com/lessons/what-s-invisible-more-than-you-think-john-lloyd

Health scare of the week: The danger of annual checkups - The Week

The danger of annual checkups

Visiting your doctor for an annual physical examination might actually have a negative impact on your health.

POSTED ON NOVEMBER 2, 2012, AT 11:49 AM

Visiting your doctor for an annual physical examination might actually have a negative impact on your health, WebMD.com reports. Danish researchers analyzed studies involving 183,000 patients and found that those who received regular checkups were no less likely to die of cancer or heart disease than those who only saw the doctor when they had symptoms. People who skipped their annual checkup were also no more likely than those who didn’t to end up in the hospital, become disabled, or miss work. Patients who saw the doctor regularly were more likely to be diagnosed with diseases and to take prescribed medication—but those added attentions didn’t seem to actually improve their health. That’s evidence that annual health check-ups actually increase the “risk of overdiagnosis,” which can lead to invasive and unnecessary biopsies, surgeries, and other treatments, says study author Lasse T. Krogsboll. Routine visits to the doctor can also cause undue stress, and sometimes even physical damage. “We are certainly not seeing the entire picture of the harms,” Krogsboll says.

More Treatment, More Mistakes - NYTimes.com

More Treatment, More Mistakes - NYTimes.com: 

July 31, 2012
Dr. Sanjay Gupta

"According to a 1999 report by the Institute of Medicine, as many as 98,000 Americans were dying every year because of medical mistakes... But a reasonable estimate is that medical mistakes now kill around 200,000 Americans every year. That would make them one of the leading causes of death in the United States. Why have these mistakes been so hard to prevent?

Here’s one theory. It is a given that American doctors perform a staggering number of tests and procedures, far more than in other industrialized nations, and far more than we used to. Since 1996, the percentage of doctor visits leading to at least five drugs’ being prescribed has nearly tripled, and the number of M.R.I. scans quadrupled.

Certainly many procedures, tests and prescriptions are based on legitimate need. But many are not. In a recent anonymous survey, orthopedic surgeons said 24 percent of the tests they ordered were medically unnecessary. This kind of treatment is a form of defensive medicine, meant less to protect the patient than to protect the doctor or hospital against potential lawsuits.

Herein lies a stunning irony. Defensive medicine is rooted in the goal of avoiding mistakes. But each additional procedure or test, no matter how cautiously performed, injects a fresh possibility of error. CT and M.R.I. scans can lead to false positives and unnecessary operations, which carry the risk of complications like infections and bleeding. The more medications patients are prescribed, the more likely they are to accidentally overdose or suffer an allergic reaction....

So what do we do to be safer? Many smart people have tackled this question. Peter Pronovost at Johns Hopkins developed a checklist shown to bring hospital-acquired infections down to close to zero. There are rules against disturbing nurses while they dispense medications and software that warns doctors when patients’ prescriptions will interact badly. There are policies designed to empower nurses to confront doctors if they see something wrong, even if a senior doctor is at fault.

What may be even more important is remembering the limits of our power. More — more procedures, more testing, more treatment — is not always better. In 1979, Stephen Bergman, under the pen name Dr. Samuel Shem, published rules for hospitals in his caustically humorous novel, “The House of God.” Rule No. 13 reads: “The delivery of medical care is to do as much nothing as possible.” First, do no harm.

 One place where I have seen these issues addressed is in Morbidity and Mortality, or M and M — a weekly gathering of doctors, off limits to the public, which serves in most hospitals as a forum for the discussion of mistakes, complications, deaths and unusual cases. It is a sort of quality-assurance conference where doctors hold one another accountable and learn from one another’s mistakes. They are some of the most candid and indelible meetings I have ever attended....

At my first M and M as a medical student, I heard the story of a patient who had received antibiotics for an upper respiratory tract infection. Two weeks later she developed joint pain and blisters on her chest and arms, a condition known as Stevens-Johnson syndrome, which can be caused by an allergic reaction to antibiotics. She ended up with sepsis, a bodywide infection, and spent two weeks in intensive care. She, too, survived, but most stunning was the doctor’s admission that her original ailment had been a mild viral illness — she hadn’t even needed the antibiotics that led to such a terrible reaction. Years later, that case still makes me think harder about every test I order and every medication I prescribe...."

Sanjay Gupta, the associate chief of neurosurgery at Grady Memorial Hospital and the chief medical correspondent for CNN, is the author of the novel “Monday Mornings.”