lunes, 3 de junio de 2013

Stem cells

This is not an easy video by any means for intermediate English students, but it is a fascinating one. It is a short extract from BBC's series Bang Goes the Theory, which investigates "the science behind the headlines (...) making sense of the everyday issues that matter to us all."

The clip below is from series 5, where reporter Liz Bonnin investigates new stem-cell research that could change organ transplant surgery.

Self-study activity:
Watch the clip through once. What can you remember?
Watch the clip again. What different parts of the human body are mentioned?
Watch the clip once again. What do the figures on the video clip refer to?

Finally watch the clip while reading the transcript below, which will also give you the chance of checking the answers. Make a note of five or six vocabulary items you wish to remember.

Now imagine this is a stem cell. Stem cells are unique, because they have the ability to generate new cells of almost any kind. They all start up as unspecialised cells, but given the right chemical and genetic signals, the stem cells can divide to form slightly more specialised cells, of different size, shape and function. And after a few more cycles of division, these can give rise to highly specialised cells, like heart muscle cells, for example, that help your heart pump the blood around your body. Given a different set of signals, this same unspecialised stem cell can go down an alternative pathway and give rise to a different type of specialised cell, like a neuron, that transmits electrical signals in the brain. Compared with stem cells from embryos, adult stem cells give rise to a smaller number of cell types, usually those of the organ or tissue in which they are found. Now, researchers have found adults stem cells in more tissues than previously thought. Bone marrow, skin, brain, liver, eyes, and this has led to research into using the patient's own adult stem cells to repair damaged organs.
Just relax back your head.
And that is exactly the focus of the trial Michael Taylor is taking part in. Led by Professor Anthony Mather at the London Chest Hospital, the trial is vitally important, because heart disease is still on the rise.
Cardiovascular disease is the number one killer in the UK, with nearly 3 million people suffering from heart conditions in the UK. Around 800,000 people suffer from this condition of heart failure. He has got a condition which makes the heart fairly weak and baggy and it doesn't work very well as a pump. What we're trying to do is see whether his own stem cells can actually repair that heart and make it pump effectively again.
So if you're looking to repair heart tissue, do you need to use heart stem cells?
Ideally, yes. The problem is that there are very few of those cells in the heart, and we have only recently discovered they are there. And the few heart stem cells that are present clearly aren't capable of repairing it. And that is really where we step in with our trials. By using bone marrow as a source of stem cells, we try and enhance the stem cells in the heart and their ability to repair the damage that has been caused.
This trial tackles heart disease on two fronts. Michael's bone marrow has already been stimulated to release enormous amounts of stem cells into his blood. And now, more are to be harvested directly from the bone marrow in his hip.
Are you OK?
Fine, thank you. It wasn't that bad at all.
As this is still a trial, only some patients will have the stem cells reinjected. Although Michael will get an injection directly into his heart, neither he nor Professor Mather know if it will contain his stem cells or a
We are about to put either stem cells or placebos into his coronary arteries. We won't know which until the end of the study, when we have treated all of our patients.
This uncertainty helps the researchers to rule out the placebo effect from any positive results they achieve. Professor Mather feeds a tube through Michael's blood vessels right back to the site of the disease in his
heart. Incredibly, Michael remains fully awake throughout the entire procedure.
Are you all right?
fine, thank you.
You can't feel anything?
No, I can't feel anything.
So that is the first half we have done. -- first artery. Now the second one and then one more and we are all finished. All finished.