[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.38,0:00:02.79,Default,,0000,0000,0000,,So, before I became a dermatologist,
Dialogue: 0,0:00:02.79,0:00:05.34,Default,,0000,0000,0000,,I started in general medicine,
Dialogue: 0,0:00:05.34,0:00:07.56,Default,,0000,0000,0000,,as most dermatologists do in Britain.
Dialogue: 0,0:00:07.56,0:00:09.60,Default,,0000,0000,0000,,At the end of that time, I went off to Australia,
Dialogue: 0,0:00:09.60,0:00:11.50,Default,,0000,0000,0000,,about 20 years ago.
Dialogue: 0,0:00:11.50,0:00:13.62,Default,,0000,0000,0000,,What you learn when you go to Australia
Dialogue: 0,0:00:13.62,0:00:16.35,Default,,0000,0000,0000,,is the Australians are very competitive.
Dialogue: 0,0:00:16.35,0:00:18.40,Default,,0000,0000,0000,,And they are not magnanimous in victory.
Dialogue: 0,0:00:18.40,0:00:20.47,Default,,0000,0000,0000,,And that happened a lot:
Dialogue: 0,0:00:20.47,0:00:22.90,Default,,0000,0000,0000,,"You pommies, you can't play cricket, rugby."
Dialogue: 0,0:00:22.90,0:00:25.02,Default,,0000,0000,0000,,I could accept that.
Dialogue: 0,0:00:25.02,0:00:27.35,Default,,0000,0000,0000,,But moving into work --
Dialogue: 0,0:00:27.35,0:00:29.88,Default,,0000,0000,0000,,and we have each week what's called a journal club,
Dialogue: 0,0:00:29.88,0:00:32.34,Default,,0000,0000,0000,,when you'd sit down with the other doctors
Dialogue: 0,0:00:32.34,0:00:34.46,Default,,0000,0000,0000,,and you'd study a scientific paper
Dialogue: 0,0:00:34.46,0:00:36.30,Default,,0000,0000,0000,,in relation to medicine.
Dialogue: 0,0:00:36.30,0:00:39.05,Default,,0000,0000,0000,,And after week one, it was about cardiovascular mortality,
Dialogue: 0,0:00:39.05,0:00:42.73,Default,,0000,0000,0000,,a dry subject -- how many people die of heart disease,
Dialogue: 0,0:00:42.73,0:00:44.12,Default,,0000,0000,0000,,what the rates are.
Dialogue: 0,0:00:44.12,0:00:46.09,Default,,0000,0000,0000,,And they were competitive about this:
Dialogue: 0,0:00:46.09,0:00:49.19,Default,,0000,0000,0000,,"You pommies, your rates of heart disease are shocking."
Dialogue: 0,0:00:49.19,0:00:51.08,Default,,0000,0000,0000,,And of course, they were right.
Dialogue: 0,0:00:51.08,0:00:55.07,Default,,0000,0000,0000,,Australians have about a third less heart disease than we do --
Dialogue: 0,0:00:55.07,0:00:58.86,Default,,0000,0000,0000,,less deaths from heart attacks, heart failure, less strokes --
Dialogue: 0,0:00:58.86,0:01:00.92,Default,,0000,0000,0000,,they're generally a healthier bunch.
Dialogue: 0,0:01:00.92,0:01:02.61,Default,,0000,0000,0000,,And of course they said this was because of
Dialogue: 0,0:01:02.61,0:01:04.67,Default,,0000,0000,0000,,their fine moral standing, their exercise,
Dialogue: 0,0:01:04.67,0:01:08.74,Default,,0000,0000,0000,,because they're Australians and we're weedy pommies, and so on.
Dialogue: 0,0:01:08.74,0:01:13.77,Default,,0000,0000,0000,,But it's not just Australia that has better health than Britain.
Dialogue: 0,0:01:13.77,0:01:17.30,Default,,0000,0000,0000,,Within Britain, there is a gradient of health --
Dialogue: 0,0:01:17.30,0:01:19.24,Default,,0000,0000,0000,,and this is what's called standardized mortality,
Dialogue: 0,0:01:19.24,0:01:21.32,Default,,0000,0000,0000,,basically your chances of dying.
Dialogue: 0,0:01:21.32,0:01:24.67,Default,,0000,0000,0000,,This is looking at data from the paper about 20 years ago,
Dialogue: 0,0:01:24.67,0:01:26.14,Default,,0000,0000,0000,,but it's true today.
Dialogue: 0,0:01:26.14,0:01:29.23,Default,,0000,0000,0000,,Comparing your rates of dying 50 degrees north --
Dialogue: 0,0:01:29.23,0:01:31.50,Default,,0000,0000,0000,,that's the South, that's London and places --
Dialogue: 0,0:01:31.50,0:01:34.85,Default,,0000,0000,0000,,by latitude, and 55 degrees --
Dialogue: 0,0:01:34.85,0:01:37.24,Default,,0000,0000,0000,,the bad news is that's here, Glasgow.
Dialogue: 0,0:01:37.24,0:01:40.08,Default,,0000,0000,0000,,I'm from Edinburgh. Worse news, that's even Edinburgh.
Dialogue: 0,0:01:40.08,0:01:44.21,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:01:44.21,0:01:47.51,Default,,0000,0000,0000,,So what accounts for this horrible space here
Dialogue: 0,0:01:47.51,0:01:49.72,Default,,0000,0000,0000,,between us up here in southern Scotland
Dialogue: 0,0:01:49.72,0:01:50.73,Default,,0000,0000,0000,,and the South?
Dialogue: 0,0:01:50.73,0:01:52.14,Default,,0000,0000,0000,,Now, we know about smoking,
Dialogue: 0,0:01:52.14,0:01:54.85,Default,,0000,0000,0000,,deep-fried Mars bars, chips -- the Glasgow diet.
Dialogue: 0,0:01:54.85,0:01:56.18,Default,,0000,0000,0000,,All of these things.
Dialogue: 0,0:01:56.18,0:01:58.97,Default,,0000,0000,0000,,But this graph is after taking into account
Dialogue: 0,0:01:58.97,0:02:01.03,Default,,0000,0000,0000,,all of these known risk factors.
Dialogue: 0,0:02:01.03,0:02:04.80,Default,,0000,0000,0000,,This is after accounting for smoking, social class, diet,
Dialogue: 0,0:02:04.80,0:02:06.54,Default,,0000,0000,0000,,all those other known risk factors.
Dialogue: 0,0:02:06.54,0:02:08.77,Default,,0000,0000,0000,,We are left with this missing space
Dialogue: 0,0:02:08.77,0:02:12.63,Default,,0000,0000,0000,,of increased deaths the further north you go.
Dialogue: 0,0:02:12.63,0:02:15.26,Default,,0000,0000,0000,,Now, sunlight, of course, comes into this.
Dialogue: 0,0:02:15.26,0:02:17.58,Default,,0000,0000,0000,,And vitamin D has had a great deal of press,
Dialogue: 0,0:02:17.58,0:02:19.59,Default,,0000,0000,0000,,and a lot of people get concerned about it.
Dialogue: 0,0:02:19.59,0:02:23.58,Default,,0000,0000,0000,,And we need vitamin D. It's now a requirement that children have a certain amount.
Dialogue: 0,0:02:23.58,0:02:25.81,Default,,0000,0000,0000,,My grandmother grew up in Glasgow,
Dialogue: 0,0:02:25.81,0:02:29.40,Default,,0000,0000,0000,,back in the 1920s and '30s when rickets was a real problem
Dialogue: 0,0:02:29.40,0:02:31.59,Default,,0000,0000,0000,,and cod liver oil was brought in.
Dialogue: 0,0:02:31.59,0:02:35.54,Default,,0000,0000,0000,,And that really prevented the rickets that used to be common in this city.
Dialogue: 0,0:02:35.54,0:02:39.46,Default,,0000,0000,0000,,And I as a child was fed cod liver oil by my grandmother.
Dialogue: 0,0:02:39.46,0:02:42.48,Default,,0000,0000,0000,,I distinctly -- nobody forgets cod liver oil.
Dialogue: 0,0:02:42.48,0:02:47.26,Default,,0000,0000,0000,,But an association: The higher people's blood levels of vitamin D are,
Dialogue: 0,0:02:47.26,0:02:50.59,Default,,0000,0000,0000,,the less heart disease they have, the less cancer.
Dialogue: 0,0:02:50.59,0:02:54.43,Default,,0000,0000,0000,,There seems to be a lot of data suggesting that vitamin D is very good for you.
Dialogue: 0,0:02:54.43,0:02:56.73,Default,,0000,0000,0000,,And it is, to prevent rickets and so on.
Dialogue: 0,0:02:56.73,0:02:59.45,Default,,0000,0000,0000,,But if you give people vitamin D supplements,
Dialogue: 0,0:02:59.45,0:03:02.88,Default,,0000,0000,0000,,you don't change that high rate of heart disease.
Dialogue: 0,0:03:02.88,0:03:06.61,Default,,0000,0000,0000,,And the evidence for it preventing cancers is not yet great.
Dialogue: 0,0:03:06.61,0:03:11.46,Default,,0000,0000,0000,,So what I'm going to suggest is that vitamin D is not the only story in town.
Dialogue: 0,0:03:11.46,0:03:14.78,Default,,0000,0000,0000,,It's not the only reason preventing heart disease.
Dialogue: 0,0:03:14.78,0:03:19.14,Default,,0000,0000,0000,,High vitamin D levels, I think, are a marker for sunlight exposure,
Dialogue: 0,0:03:19.14,0:03:22.36,Default,,0000,0000,0000,,and sunlight exposure, in methods I'm going to show,
Dialogue: 0,0:03:22.36,0:03:24.80,Default,,0000,0000,0000,,is good for heart disease.
Dialogue: 0,0:03:24.80,0:03:26.76,Default,,0000,0000,0000,,Anyway, I came back from Australia,
Dialogue: 0,0:03:26.76,0:03:30.26,Default,,0000,0000,0000,,and despite the obvious risks to my health, I moved to Aberdeen.
Dialogue: 0,0:03:30.26,0:03:32.81,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:03:32.81,0:03:35.96,Default,,0000,0000,0000,,Now, in Aberdeen, I started my dermatology training.
Dialogue: 0,0:03:35.96,0:03:37.90,Default,,0000,0000,0000,,But I also became interested in research,
Dialogue: 0,0:03:37.90,0:03:41.08,Default,,0000,0000,0000,,and in particular I became interested in this substance, nitric oxide.
Dialogue: 0,0:03:41.08,0:03:42.45,Default,,0000,0000,0000,,Now these three guys up here,
Dialogue: 0,0:03:42.45,0:03:44.02,Default,,0000,0000,0000,,Furchgott, Ignarro and Murad,
Dialogue: 0,0:03:44.02,0:03:47.29,Default,,0000,0000,0000,,won the Nobel Prize for medicine back in 1998.
Dialogue: 0,0:03:47.29,0:03:49.43,Default,,0000,0000,0000,,And they were the first people to describe
Dialogue: 0,0:03:49.43,0:03:52.77,Default,,0000,0000,0000,,this new chemical transmitter, nitric oxide.
Dialogue: 0,0:03:52.77,0:03:55.80,Default,,0000,0000,0000,,What nitric oxide does is it dilates blood vessels,
Dialogue: 0,0:03:55.80,0:03:57.67,Default,,0000,0000,0000,,so it lowers your blood pressure.
Dialogue: 0,0:03:57.67,0:04:01.84,Default,,0000,0000,0000,,It also dilates the coronary arteries, so it stops angina.
Dialogue: 0,0:04:01.84,0:04:03.22,Default,,0000,0000,0000,,And what was remarkable about it
Dialogue: 0,0:04:03.22,0:04:07.29,Default,,0000,0000,0000,,was in the past when we think of chemical messengers within the body,
Dialogue: 0,0:04:07.29,0:04:10.46,Default,,0000,0000,0000,,we thought of complicated things like estrogen and insulin,
Dialogue: 0,0:04:10.46,0:04:11.93,Default,,0000,0000,0000,,or nerve transmission.
Dialogue: 0,0:04:11.93,0:04:15.23,Default,,0000,0000,0000,,Very complex processes with very complex chemicals
Dialogue: 0,0:04:15.23,0:04:17.52,Default,,0000,0000,0000,,that fit into very complex receptors.
Dialogue: 0,0:04:17.52,0:04:19.88,Default,,0000,0000,0000,,And here's this incredibly simple molecule,
Dialogue: 0,0:04:19.88,0:04:23.22,Default,,0000,0000,0000,,a nitrogen and an oxygen that are stuck together,
Dialogue: 0,0:04:23.22,0:04:27.85,Default,,0000,0000,0000,,and yet these are hugely important for [unclear] our low blood pressure,
Dialogue: 0,0:04:27.85,0:04:30.45,Default,,0000,0000,0000,,for neurotransmission, for many, many things,
Dialogue: 0,0:04:30.45,0:04:33.85,Default,,0000,0000,0000,,but particularly cardiovascular health.
Dialogue: 0,0:04:33.85,0:04:37.16,Default,,0000,0000,0000,,And I started doing research, and we found, very excitingly,
Dialogue: 0,0:04:37.16,0:04:39.77,Default,,0000,0000,0000,,that the skin produces nitric oxide.
Dialogue: 0,0:04:39.77,0:04:42.66,Default,,0000,0000,0000,,So it's not just in the cardiovascular system it arises.
Dialogue: 0,0:04:42.66,0:04:44.53,Default,,0000,0000,0000,,It arises in the skin.
Dialogue: 0,0:04:44.53,0:04:46.40,Default,,0000,0000,0000,,Well, having found that and published that,
Dialogue: 0,0:04:46.40,0:04:48.45,Default,,0000,0000,0000,,I thought, well, what's it doing?
Dialogue: 0,0:04:48.45,0:04:49.93,Default,,0000,0000,0000,,How do you have low blood pressure in your skin?
Dialogue: 0,0:04:49.93,0:04:52.02,Default,,0000,0000,0000,,It's not the heart. What do you do?
Dialogue: 0,0:04:52.02,0:04:56.09,Default,,0000,0000,0000,,So I went off to the States, as many people do if they're going to do research,
Dialogue: 0,0:04:56.09,0:04:59.83,Default,,0000,0000,0000,,and I spent a few years in Pittsburgh. This is Pittsburgh.
Dialogue: 0,0:04:59.83,0:05:02.44,Default,,0000,0000,0000,,And I was interested in these really complex systems.
Dialogue: 0,0:05:02.44,0:05:06.48,Default,,0000,0000,0000,,We thought that maybe nitric oxide affected cell death,
Dialogue: 0,0:05:06.48,0:05:08.96,Default,,0000,0000,0000,,and how cells survive, and their resistance to other things.
Dialogue: 0,0:05:08.96,0:05:12.33,Default,,0000,0000,0000,,And I first off started work in cell culture, growing cells,
Dialogue: 0,0:05:12.33,0:05:14.45,Default,,0000,0000,0000,,and then I was using knockout mouse models --
Dialogue: 0,0:05:14.45,0:05:16.19,Default,,0000,0000,0000,,mice that couldn't make the gene.
Dialogue: 0,0:05:16.19,0:05:20.60,Default,,0000,0000,0000,,We worked out a mechanism, which -- NO was helping cells survive.
Dialogue: 0,0:05:20.60,0:05:24.42,Default,,0000,0000,0000,,And I then moved back to Edinburgh.
Dialogue: 0,0:05:24.42,0:05:27.20,Default,,0000,0000,0000,,And in Edinburgh, the experimental animal we use is the medical student.
Dialogue: 0,0:05:27.20,0:05:29.26,Default,,0000,0000,0000,,It's a species close to human,
Dialogue: 0,0:05:29.26,0:05:31.16,Default,,0000,0000,0000,,with several advantages over mice:
Dialogue: 0,0:05:31.16,0:05:34.62,Default,,0000,0000,0000,,They're free, you don't shave them, they feed themselves,
Dialogue: 0,0:05:34.62,0:05:36.74,Default,,0000,0000,0000,,and nobody pickets your office saying,
Dialogue: 0,0:05:36.74,0:05:39.14,Default,,0000,0000,0000,,"Save the lab medical student."
Dialogue: 0,0:05:39.14,0:05:42.40,Default,,0000,0000,0000,,So they're really an ideal model.
Dialogue: 0,0:05:42.40,0:05:44.36,Default,,0000,0000,0000,,But what we found
Dialogue: 0,0:05:44.36,0:05:48.98,Default,,0000,0000,0000,,was that we couldn't reproduce in man the data we had shown in mice.
Dialogue: 0,0:05:48.98,0:05:52.22,Default,,0000,0000,0000,,It seemed we couldn't turn off the production
Dialogue: 0,0:05:52.22,0:05:55.30,Default,,0000,0000,0000,,of nitric oxide in the skin of humans.
Dialogue: 0,0:05:55.30,0:05:58.09,Default,,0000,0000,0000,,We put on creams that blocked the enzyme that made it,
Dialogue: 0,0:05:58.09,0:06:02.48,Default,,0000,0000,0000,,we injected things. We couldn't turn off the nitric oxide.
Dialogue: 0,0:06:02.48,0:06:05.74,Default,,0000,0000,0000,,And the reason for this, it turned out, after two or three years' work,
Dialogue: 0,0:06:05.74,0:06:09.79,Default,,0000,0000,0000,,was that in the skin we have huge stores
Dialogue: 0,0:06:09.79,0:06:12.88,Default,,0000,0000,0000,,not of nitric oxide, because nitric oxide is a gas,
Dialogue: 0,0:06:12.88,0:06:16.03,Default,,0000,0000,0000,,and it's released -- (Poof!) -- and in a few seconds it's away,
Dialogue: 0,0:06:16.03,0:06:19.25,Default,,0000,0000,0000,,but it can be turned into these forms of nitric oxide --
Dialogue: 0,0:06:19.25,0:06:22.88,Default,,0000,0000,0000,,nitrate, NO3; nitrite, NO2; nitrosothiols.
Dialogue: 0,0:06:22.88,0:06:24.30,Default,,0000,0000,0000,,And these are more stable,
Dialogue: 0,0:06:24.30,0:06:28.46,Default,,0000,0000,0000,,and your skin has got really large stores of NO.
Dialogue: 0,0:06:28.46,0:06:31.28,Default,,0000,0000,0000,,And we then thought to ourselves, with those big stores,
Dialogue: 0,0:06:31.28,0:06:34.60,Default,,0000,0000,0000,,I wonder if sunlight might activate those stores
Dialogue: 0,0:06:34.60,0:06:36.34,Default,,0000,0000,0000,,and release them from the skin,
Dialogue: 0,0:06:36.34,0:06:39.73,Default,,0000,0000,0000,,where the stores are about 10 times as big as what's in the circulation.
Dialogue: 0,0:06:39.73,0:06:42.57,Default,,0000,0000,0000,,Could the sun activate those stores into the circulation,
Dialogue: 0,0:06:42.57,0:06:47.81,Default,,0000,0000,0000,,and there in the circulation do its good things for your cardiovascular system?
Dialogue: 0,0:06:47.81,0:06:50.34,Default,,0000,0000,0000,,Well, I'm an experimental dermatologist,
Dialogue: 0,0:06:50.34,0:06:51.64,Default,,0000,0000,0000,,so what we did was we thought
Dialogue: 0,0:06:51.64,0:06:55.17,Default,,0000,0000,0000,,we'd have to expose our experimental animals to sunlight.
Dialogue: 0,0:06:55.17,0:06:59.25,Default,,0000,0000,0000,,And so what we did was we took a bunch of volunteers
Dialogue: 0,0:06:59.25,0:07:01.95,Default,,0000,0000,0000,,and we exposed them to ultraviolet light.
Dialogue: 0,0:07:01.95,0:07:03.68,Default,,0000,0000,0000,,So these are kind of sunlamps.
Dialogue: 0,0:07:03.68,0:07:06.37,Default,,0000,0000,0000,,Now, what we were careful to do was,
Dialogue: 0,0:07:06.37,0:07:09.33,Default,,0000,0000,0000,,vitamin D is made by ultraviolet B rays
Dialogue: 0,0:07:09.33,0:07:13.31,Default,,0000,0000,0000,,and we wanted to separate our story from the vitamin D story.
Dialogue: 0,0:07:13.31,0:07:17.16,Default,,0000,0000,0000,,So we used ultraviolet A, which doesn't make vitamin D.
Dialogue: 0,0:07:17.16,0:07:19.44,Default,,0000,0000,0000,,When we put people under a lamp
Dialogue: 0,0:07:19.44,0:07:24.51,Default,,0000,0000,0000,,for the equivalent of about 30 minutes of sunshine in summer in Edinburgh,
Dialogue: 0,0:07:24.51,0:07:27.05,Default,,0000,0000,0000,,what we produced was, we produced a rise
Dialogue: 0,0:07:27.05,0:07:29.05,Default,,0000,0000,0000,,in circulating nitric oxide.
Dialogue: 0,0:07:29.05,0:07:31.89,Default,,0000,0000,0000,,So we put patients with these subjects under the UV,
Dialogue: 0,0:07:31.89,0:07:34.31,Default,,0000,0000,0000,,and their NO levels do go up,
Dialogue: 0,0:07:34.31,0:07:36.45,Default,,0000,0000,0000,,and their blood pressure goes down.
Dialogue: 0,0:07:36.45,0:07:38.82,Default,,0000,0000,0000,,Not by much, as an individual level,
Dialogue: 0,0:07:38.82,0:07:41.19,Default,,0000,0000,0000,,but enough at a population level
Dialogue: 0,0:07:41.19,0:07:44.91,Default,,0000,0000,0000,,to shift the rates of heart disease in a whole population.
Dialogue: 0,0:07:44.91,0:07:47.33,Default,,0000,0000,0000,,And when we shone UV at them,
Dialogue: 0,0:07:47.33,0:07:50.100,Default,,0000,0000,0000,,or when we warmed them up to the same level as the lamps,
Dialogue: 0,0:07:50.100,0:07:54.26,Default,,0000,0000,0000,,but didn't actually let the rays hit the skin, this didn't happen.
Dialogue: 0,0:07:54.26,0:07:58.12,Default,,0000,0000,0000,,So this seems to be a feature of ultraviolet rays hitting the skin.
Dialogue: 0,0:07:58.12,0:07:59.95,Default,,0000,0000,0000,,Now, we're still collecting data.
Dialogue: 0,0:07:59.95,0:08:01.39,Default,,0000,0000,0000,,A few good things here:
Dialogue: 0,0:08:01.39,0:08:04.54,Default,,0000,0000,0000,,This appeared to be more marked in older people.
Dialogue: 0,0:08:04.54,0:08:06.15,Default,,0000,0000,0000,,I'm not sure exactly how much.
Dialogue: 0,0:08:06.15,0:08:07.93,Default,,0000,0000,0000,,One of the subjects here was my mother-in-law,
Dialogue: 0,0:08:07.93,0:08:10.88,Default,,0000,0000,0000,,and clearly I do not know her age.
Dialogue: 0,0:08:10.88,0:08:14.31,Default,,0000,0000,0000,,But certainly in people older than my wife,
Dialogue: 0,0:08:14.31,0:08:17.44,Default,,0000,0000,0000,,this appears to be a more marked effect.
Dialogue: 0,0:08:17.44,0:08:18.70,Default,,0000,0000,0000,,And the other thing I should mention
Dialogue: 0,0:08:18.70,0:08:20.75,Default,,0000,0000,0000,,was there was no change in vitamin D.
Dialogue: 0,0:08:20.75,0:08:22.87,Default,,0000,0000,0000,,This is separate from vitamin D.
Dialogue: 0,0:08:22.87,0:08:24.41,Default,,0000,0000,0000,,So vitamin D is good for you -- it stops rickets,
Dialogue: 0,0:08:24.41,0:08:26.65,Default,,0000,0000,0000,,it prevents calcium metabolism, important stuff.
Dialogue: 0,0:08:26.65,0:08:29.68,Default,,0000,0000,0000,,But this is a separate mechanism from vitamin D.
Dialogue: 0,0:08:29.68,0:08:32.26,Default,,0000,0000,0000,,Now, one of the problems with looking at blood pressure
Dialogue: 0,0:08:32.26,0:08:33.81,Default,,0000,0000,0000,,is your body does everything it can
Dialogue: 0,0:08:33.81,0:08:35.39,Default,,0000,0000,0000,,to keep your blood pressure at the same place.
Dialogue: 0,0:08:35.39,0:08:37.04,Default,,0000,0000,0000,,If your leg is chopped off and you lose blood,
Dialogue: 0,0:08:37.04,0:08:39.94,Default,,0000,0000,0000,,your body will clamp down, increase the heart rate,
Dialogue: 0,0:08:39.94,0:08:42.17,Default,,0000,0000,0000,,do everything it can to keep your blood pressure up.
Dialogue: 0,0:08:42.17,0:08:45.14,Default,,0000,0000,0000,,That is an absolutely fundamental physiological principle.
Dialogue: 0,0:08:45.14,0:08:46.95,Default,,0000,0000,0000,,So what we've next done
Dialogue: 0,0:08:46.95,0:08:50.61,Default,,0000,0000,0000,,is we've moved on to looking at blood vessel dilatation.
Dialogue: 0,0:08:50.61,0:08:52.10,Default,,0000,0000,0000,,So we've measured -- this is again,
Dialogue: 0,0:08:52.10,0:08:57.43,Default,,0000,0000,0000,,notice no tail and hairless, this is a medical student.
Dialogue: 0,0:08:57.43,0:09:00.05,Default,,0000,0000,0000,,In the arm, you can measure blood flow in the arm
Dialogue: 0,0:09:00.05,0:09:03.28,Default,,0000,0000,0000,,by how much it swells up as some blood flows into it.
Dialogue: 0,0:09:03.28,0:09:06.76,Default,,0000,0000,0000,,And what we've shown is that doing a sham irradiation --
Dialogue: 0,0:09:06.76,0:09:08.23,Default,,0000,0000,0000,,this is the thick line here --
Dialogue: 0,0:09:08.23,0:09:10.63,Default,,0000,0000,0000,,this is shining UV on the arm so it warms up
Dialogue: 0,0:09:10.63,0:09:13.45,Default,,0000,0000,0000,,but keeping it covered so the rays don't hit the skin.
Dialogue: 0,0:09:13.45,0:09:17.36,Default,,0000,0000,0000,,There is no change in blood flow, in dilatation of the blood vessels.
Dialogue: 0,0:09:17.36,0:09:19.21,Default,,0000,0000,0000,,But the active irradiation,
Dialogue: 0,0:09:19.21,0:09:22.56,Default,,0000,0000,0000,,during the UV and for an hour after it,
Dialogue: 0,0:09:22.56,0:09:24.66,Default,,0000,0000,0000,,there is dilation of the blood vessels.
Dialogue: 0,0:09:24.66,0:09:27.26,Default,,0000,0000,0000,,This is the mechanism by which you lower blood pressure,
Dialogue: 0,0:09:27.26,0:09:29.64,Default,,0000,0000,0000,,by which you dilate the coronary arteries also,
Dialogue: 0,0:09:29.64,0:09:31.35,Default,,0000,0000,0000,,to let the blood be supplied with the heart.
Dialogue: 0,0:09:31.35,0:09:35.74,Default,,0000,0000,0000,,So here, further data that ultraviolet -- that's sunlight --
Dialogue: 0,0:09:35.74,0:09:40.62,Default,,0000,0000,0000,,has benefits on the blood flow and the cardiovascular system.
Dialogue: 0,0:09:40.62,0:09:42.96,Default,,0000,0000,0000,,So we thought we'd just kind of model --
Dialogue: 0,0:09:42.96,0:09:49.21,Default,,0000,0000,0000,,Different amounts of UV hit different parts of the Earth at different times of year,
Dialogue: 0,0:09:49.21,0:09:53.24,Default,,0000,0000,0000,,so you can actually work out those stores of nitric oxide --
Dialogue: 0,0:09:53.24,0:09:55.49,Default,,0000,0000,0000,,the nitrates, nitrites, nitrosothiols in the skin --
Dialogue: 0,0:09:55.49,0:09:58.36,Default,,0000,0000,0000,,cleave to release NO.
Dialogue: 0,0:09:58.36,0:10:02.19,Default,,0000,0000,0000,,Different wavelengths of light have different activities of doing that.
Dialogue: 0,0:10:02.19,0:10:04.27,Default,,0000,0000,0000,,So you can look at the wavelengths of light that do that.
Dialogue: 0,0:10:04.27,0:10:08.25,Default,,0000,0000,0000,,And you can look -- So, if you live on the equator, the sun comes straight overhead,
Dialogue: 0,0:10:08.25,0:10:10.07,Default,,0000,0000,0000,,it comes through a very thin bit of atmosphere.
Dialogue: 0,0:10:10.07,0:10:12.51,Default,,0000,0000,0000,,In winter or summer, it's the same amount of light.
Dialogue: 0,0:10:12.51,0:10:15.02,Default,,0000,0000,0000,,If you live up here, in summer
Dialogue: 0,0:10:15.02,0:10:17.68,Default,,0000,0000,0000,,the sun is coming fairly directly down,
Dialogue: 0,0:10:17.68,0:10:20.98,Default,,0000,0000,0000,,but in winter it's coming through a huge amount of atmosphere,
Dialogue: 0,0:10:20.98,0:10:24.20,Default,,0000,0000,0000,,and much of the ultraviolet is weeded out,
Dialogue: 0,0:10:24.20,0:10:26.56,Default,,0000,0000,0000,,and the range of wavelengths that hit the Earth
Dialogue: 0,0:10:26.56,0:10:28.88,Default,,0000,0000,0000,,are different from summer to winter.
Dialogue: 0,0:10:28.88,0:10:30.83,Default,,0000,0000,0000,,So what you can do is you can multiply those data
Dialogue: 0,0:10:30.83,0:10:32.82,Default,,0000,0000,0000,,by the NO that's released
Dialogue: 0,0:10:32.82,0:10:36.00,Default,,0000,0000,0000,,and you can calculate how much nitric oxide
Dialogue: 0,0:10:36.00,0:10:39.17,Default,,0000,0000,0000,,would be released from the skin into the circulation.
Dialogue: 0,0:10:39.17,0:10:41.17,Default,,0000,0000,0000,,Now, if you're on the equator here --
Dialogue: 0,0:10:41.17,0:10:44.60,Default,,0000,0000,0000,,that's these two lines here, the red line and the purple line --
Dialogue: 0,0:10:44.60,0:10:48.100,Default,,0000,0000,0000,,the amount of nitric oxide that's released is the area under the curve,
Dialogue: 0,0:10:48.100,0:10:51.03,Default,,0000,0000,0000,,it's the area in this space here.
Dialogue: 0,0:10:51.03,0:10:53.72,Default,,0000,0000,0000,,So if you're on the equator, December or June,
Dialogue: 0,0:10:53.72,0:10:56.98,Default,,0000,0000,0000,,you've got masses of NO being released from the skin.
Dialogue: 0,0:10:56.98,0:10:59.44,Default,,0000,0000,0000,,So Ventura is in southern California.
Dialogue: 0,0:10:59.44,0:11:01.66,Default,,0000,0000,0000,,In summer, you might as well be at the equator.
Dialogue: 0,0:11:01.66,0:11:03.72,Default,,0000,0000,0000,,It's great. Lots of NO is released.
Dialogue: 0,0:11:03.72,0:11:07.66,Default,,0000,0000,0000,,Ventura mid-winter, well, there's still a decent amount.
Dialogue: 0,0:11:07.66,0:11:11.62,Default,,0000,0000,0000,,Edinburgh in summer, the area beneath the curve is pretty good,
Dialogue: 0,0:11:11.62,0:11:15.84,Default,,0000,0000,0000,,but Edinburgh in winter, the amount of NO that can be released
Dialogue: 0,0:11:15.84,0:11:19.69,Default,,0000,0000,0000,,is next to nothing, tiny amounts.
Dialogue: 0,0:11:19.69,0:11:21.50,Default,,0000,0000,0000,,So what do we think?
Dialogue: 0,0:11:21.50,0:11:23.09,Default,,0000,0000,0000,,We're still working at this story,
Dialogue: 0,0:11:23.09,0:11:25.00,Default,,0000,0000,0000,,we're still developing it, we're still expanding it.
Dialogue: 0,0:11:25.00,0:11:26.65,Default,,0000,0000,0000,,We think it's very important.
Dialogue: 0,0:11:26.65,0:11:30.24,Default,,0000,0000,0000,,We think it probably accounts for a lot of the north-south health divide within Britain,
Dialogue: 0,0:11:30.24,0:11:31.87,Default,,0000,0000,0000,,It's of relevance to us.
Dialogue: 0,0:11:31.87,0:11:33.56,Default,,0000,0000,0000,,We think that the skin --
Dialogue: 0,0:11:33.56,0:11:36.45,Default,,0000,0000,0000,,well, we know that the skin has got very large stores
Dialogue: 0,0:11:36.45,0:11:38.67,Default,,0000,0000,0000,,of nitric oxide as these various other forms.
Dialogue: 0,0:11:38.67,0:11:40.55,Default,,0000,0000,0000,,We suspect a lot of these come from diet,
Dialogue: 0,0:11:40.55,0:11:42.82,Default,,0000,0000,0000,,green leafy vegetables, beetroot, lettuce
Dialogue: 0,0:11:42.82,0:11:46.14,Default,,0000,0000,0000,,has a lot of these nitric oxides that we think go to the skin.
Dialogue: 0,0:11:46.14,0:11:48.28,Default,,0000,0000,0000,,We think they're then stored in the skin,
Dialogue: 0,0:11:48.28,0:11:50.68,Default,,0000,0000,0000,,and we think the sunlight releases this
Dialogue: 0,0:11:50.68,0:11:53.32,Default,,0000,0000,0000,,where it has generally beneficial effects.
Dialogue: 0,0:11:53.32,0:11:55.79,Default,,0000,0000,0000,,And this is ongoing work, but dermatologists --
Dialogue: 0,0:11:55.79,0:11:57.51,Default,,0000,0000,0000,,I mean, I'm a dermatologist.
Dialogue: 0,0:11:57.51,0:12:00.04,Default,,0000,0000,0000,,My day job is saying to people, "You've got skin cancer,
Dialogue: 0,0:12:00.04,0:12:01.92,Default,,0000,0000,0000,,it's caused by sunlight, don't go in the sun."
Dialogue: 0,0:12:01.92,0:12:04.66,Default,,0000,0000,0000,,I actually think a far more important message
Dialogue: 0,0:12:04.66,0:12:08.08,Default,,0000,0000,0000,,is that there are benefits as well as risks to sunlight.
Dialogue: 0,0:12:08.08,0:12:13.84,Default,,0000,0000,0000,,Yes, sunlight is the major alterable risk factor for skin cancer,
Dialogue: 0,0:12:13.84,0:12:16.71,Default,,0000,0000,0000,,but deaths from heart disease are a hundred times higher
Dialogue: 0,0:12:16.71,0:12:18.66,Default,,0000,0000,0000,,than deaths from skin cancer.
Dialogue: 0,0:12:18.66,0:12:21.31,Default,,0000,0000,0000,,And I think that we need to be more aware of,
Dialogue: 0,0:12:21.31,0:12:23.39,Default,,0000,0000,0000,,and we need to find the risk-benefit ratio.
Dialogue: 0,0:12:23.39,0:12:24.86,Default,,0000,0000,0000,,How much sunlight is safe,
Dialogue: 0,0:12:24.86,0:12:29.06,Default,,0000,0000,0000,,and how can we finesse this best for our general health?
Dialogue: 0,0:12:29.06,0:12:31.24,Default,,0000,0000,0000,,So, thank you very much indeed.
Dialogue: 0,0:12:31.24,0:12:38.14,Default,,0000,0000,0000,,(Applause)