Richard Weller: Could the sun be good for your heart?

87,914 views ・ 2013-01-17

TED


Dvaput kliknite na engleske titlove ispod za reprodukciju videozapisa.

00:00
Translator: Morton Bast Reviewer: Thu-Huong Ha
0
0
7000
Prevoditelj: Maja Budišin Lukin Recezent: Mladen Barešić
00:15
So, before I became a dermatologist,
1
15640
2407
Prije no što sam postao dermatolog,
00:18
I started in general medicine,
2
18047
2552
započeo sam se baviti općom medicinom,
00:20
as most dermatologists do in Britain.
3
20599
2216
poput većine dermatologa u Britaniji.
00:22
At the end of that time, I went off to Australia,
4
22815
2048
Na kraju tog razdoblja, otišao sam u Australiju.
00:24
about 20 years ago.
5
24863
1896
Prije 20-ak godina.
00:26
What you learn when you go to Australia
6
26759
2121
U Australiji naučite
00:28
is the Australians are very competitive.
7
28880
2726
da su Australci vrlo kompetitivni.
00:31
And they are not magnanimous in victory.
8
31606
2057
I nisu velikodušni u pobjedi.
00:33
And that happened a lot:
9
33663
2064
Puno se puta to događalo...
00:35
"You pommies, you can't play cricket, rugby."
10
35727
2432
"Vi, dotepenci britanski, ne znate igrati kriket, ragbi..."
00:38
I could accept that.
11
38159
2118
To sam mogao prihvatiti.
00:40
But moving into work --
12
40277
2330
Ali... prijeđimo na posao...
00:42
and we have each week what's called a journal club,
13
42607
2538
Svakog tjedna okupljamo se u tzv. znanstvenom klubu,
00:45
when you'd sit down with the other doctors
14
45145
2458
gdje mi, liječnici, međusobno razgovaramo
00:47
and you'd study a scientific paper
15
47603
2120
i proučavamo znanstvene radove
00:49
in relation to medicine.
16
49723
1841
iz medicinskog područja.
00:51
And after week one, it was about cardiovascular mortality,
17
51564
2749
Drugog tjedna... Tema je bila smrtnost od kardiovaskularnih bolesti.
00:54
a dry subject -- how many people die of heart disease,
18
54313
3680
Suhoparno područje! Koliko ljudi umire od srčanih bolesti,
00:57
what the rates are.
19
57993
1384
kolike su stope smrtnosti...?
00:59
And they were competitive about this:
20
59377
1976
I u tome su bili natjecateljski raspoloženi...
01:01
"You pommies, your rates of heart disease are shocking."
21
61353
3096
"Vi, dotepenci britanski, vaše stope srčanih bolesti su šokantne!
01:04
And of course, they were right.
22
64449
1896
I, naravno, bili su u pravu.
01:06
Australians have about a third less heart disease than we do --
23
66345
3981
Australci imaju oko trećinu manje srčanih bolesti od nas.
01:10
less deaths from heart attacks, heart failure, less strokes --
24
70326
3791
Manje smrtnih slučajeva od srčanog udara, zatajenja srca, manje moždanih udara...
01:14
they're generally a healthier bunch.
25
74117
2060
Općenito su zdravija družina.
01:16
And of course they said this was because of
26
76177
1691
I, naravno, rekli su da je to zbog
01:17
their fine moral standing, their exercise,
27
77868
2064
njihovih visokih moralnih gledišta, njihovog vježbanja,
01:19
because they're Australians and we're weedy pommies, and so on.
28
79932
4068
jer oni su Australci, a mi smo pripiti britanski dotepenci,...
01:24
But it's not just Australia that has better health than Britain.
29
84000
5031
Ali, nije Australija jedina zemlja u kojoj su ljudi boljeg zdravlja od Britanaca.
01:29
Within Britain, there is a gradient of health --
30
89031
3528
U Velikoj Britaniji, koristimo se tzv. gradijentom zdravlja -
01:32
and this is what's called standardized mortality,
31
92559
1936
to je ono što se naziva standardiziranom stopom smrtnosti -
01:34
basically your chances of dying.
32
94495
2088
u osnovi, vjerojatnost da ćete umrijeti.
01:36
This is looking at data from the paper about 20 years ago,
33
96583
3344
Ovo su podaci iz istraživanja od prije 20-ak godina,
01:39
but it's true today.
34
99927
1475
ali vrijede i danas.
01:41
Comparing your rates of dying 50 degrees north --
35
101402
3090
Uspoređujući stope umiranja na 50 stupnjeva sjeverne zemljopisne širine -
01:44
that's the South, that's London and places --
36
104492
2267
to je jug... London, i obližnja mjesta -
01:46
by latitude, and 55 degrees --
37
106759
3352
s onima na 55 stupnjeva...
01:50
the bad news is that's here, Glasgow.
38
110111
2384
Loša vijest je da je to ovdje - Glasgow.
01:52
I'm from Edinburgh. Worse news, that's even Edinburgh.
39
112495
2848
Ja sam iz Edinburgha. Još gora vijest - to je čak i Edinburgh.
01:55
(Laughter)
40
115343
4124
(Smijeh)
01:59
So what accounts for this horrible space here
41
119467
3306
Kako objasniti ovu strašnu razliku
02:02
between us up here in southern Scotland
42
122773
2204
između nas ovdje gore, na jugu Škotske,
02:04
and the South?
43
124977
1010
i ljudi na jugu Engleske?
02:05
Now, we know about smoking,
44
125987
1418
O pušenju sve znamo,
02:07
deep-fried Mars bars, chips -- the Glasgow diet.
45
127405
2702
o prženim čokoladicama, čipsu, prehrani u Glasgowu....
02:10
All of these things.
46
130107
1328
O svim tim stvarima.
02:11
But this graph is after taking into account
47
131435
2792
Ali, ovaj prikaz uzima u obzir
02:14
all of these known risk factors.
48
134227
2064
sve te poznate rizične čimbenike:
02:16
This is after accounting for smoking, social class, diet,
49
136291
3769
i pušenje, i društvenu klasu, prehranu,
02:20
all those other known risk factors.
50
140060
1743
i sve ostale poznate rizične čimbenike.
02:21
We are left with this missing space
51
141803
2224
No, nedostaje nam i dalje razlog
02:24
of increased deaths the further north you go.
52
144027
3860
povećane smrtnosti što dalje idemo prema sjeveru.
02:27
Now, sunlight, of course, comes into this.
53
147887
2637
Naravno, ne zaboravimo na Sunčevu svjetlost...
02:30
And vitamin D has had a great deal of press,
54
150524
2320
O vitaminu D je u tisku bilo puno govora,
02:32
and a lot of people get concerned about it.
55
152844
2002
i zainteresirano je mnogo ljudi.
02:34
And we need vitamin D. It's now a requirement that children have a certain amount.
56
154846
3992
Nama je vitamin D potreban! Danas ga djeca moraju imati u određenoj količini.
02:38
My grandmother grew up in Glasgow,
57
158838
2232
Moja je baka odrasla u Glasgowu,
02:41
back in the 1920s and '30s when rickets was a real problem
58
161070
3586
1920-ih i 30-ih kada je rahitis bio istinski problem,
02:44
and cod liver oil was brought in.
59
164656
2198
i kad je u liječenje uvedeno bakalarevo jetreno ulje.
02:46
And that really prevented the rickets that used to be common in this city.
60
166854
3944
To je doista zaustavilo rahitis, dotad uobičajen u ovom gradu.
02:50
And I as a child was fed cod liver oil by my grandmother.
61
170798
3920
I mene je moja baka u djetinjstvu hranila bakalarevim jetrenim uljem.
02:54
I distinctly -- nobody forgets cod liver oil.
62
174718
3024
Jako se dobro sjećam... nitko ne zaboravlja bakalarevo jetreno ulje!
02:57
But an association: The higher people's blood levels of vitamin D are,
63
177742
4782
Jedna asocijacija: što je viša razina vitamina D u krvi,
03:02
the less heart disease they have, the less cancer.
64
182524
3327
rjeđe su srčane bolesti, rjeđi je rak.
03:05
There seems to be a lot of data suggesting that vitamin D is very good for you.
65
185851
3842
Čini se da dosta podataka ukazuje da je vitamin D vrlo dobar za sve nas.
03:09
And it is, to prevent rickets and so on.
66
189693
2294
I jest, za sprečavanje rahitisa i sličnih bolesti...
03:11
But if you give people vitamin D supplements,
67
191987
2720
No, prepisujete li ljudima dodatke vitaminu D,
03:14
you don't change that high rate of heart disease.
68
194707
3432
ne smanjujete tu visoku stopu srčanih bolesti.
03:18
And the evidence for it preventing cancers is not yet great.
69
198139
3728
I dokazi da oni sprečavaju nastanak raka još uvijek nisu uvjerljivi.
03:21
So what I'm going to suggest is that vitamin D is not the only story in town.
70
201867
4857
Zato bih naglasio da vitamin D nije jedino o čemu vrijedi govoriti.
03:26
It's not the only reason preventing heart disease.
71
206724
3311
On nije jedino što sprečava pojavu srčanih bolesti.
03:30
High vitamin D levels, I think, are a marker for sunlight exposure,
72
210035
4369
Smatram da je visoka razina vitamina D pokazatelj izlaganja suncu,
03:34
and sunlight exposure, in methods I'm going to show,
73
214404
3215
a izlaganje suncu, u postupcima koje ću prikazati,
03:37
is good for heart disease.
74
217619
2439
blagotvorno je za srčane bolesti.
03:40
Anyway, I came back from Australia,
75
220058
1961
Kako god, vrativši se iz Australije,
03:42
and despite the obvious risks to my health, I moved to Aberdeen.
76
222019
3496
i unatoč očitim rizicima za moje zdravlje, preselio sam se u Aberdeen.
03:45
(Laughter)
77
225515
2552
(Smijeh)
03:48
Now, in Aberdeen, I started my dermatology training.
78
228067
3151
U Aberdeenu sam započeo s dermatološkom izobrazbom.
03:51
But I also became interested in research,
79
231218
1945
Međutim, zainteresirao sam se i za istraživanje,
03:53
and in particular I became interested in this substance, nitric oxide.
80
233163
3175
i to osobito dušikovog oksida.
03:56
Now these three guys up here,
81
236338
1376
Ova trojica ovdje,
03:57
Furchgott, Ignarro and Murad,
82
237714
1570
Furchgott, Ignarro i Murad,
03:59
won the Nobel Prize for medicine back in 1998.
83
239284
3262
osvojila su Nobelovu nagradu za medicinu 1998.
04:02
And they were the first people to describe
84
242546
2143
Oni su bili prvi koji su opisali
04:04
this new chemical transmitter, nitric oxide.
85
244689
3345
ovaj novi kemijski prijenosnik - dušikov oksid.
04:08
What nitric oxide does is it dilates blood vessels,
86
248034
3025
Dušikov oksid proširuje krvne žile
04:11
so it lowers your blood pressure.
87
251059
1871
snižavajući tako krvni tlak.
04:12
It also dilates the coronary arteries, so it stops angina.
88
252930
4167
Proširuje i srčane arterije, onemogućavajući tako anginu.
04:17
And what was remarkable about it
89
257097
1386
S time u vezi,
04:18
was in the past when we think of chemical messengers within the body,
90
258483
4071
značajno je da smo nekoć, sjetimo li se kemijskih glasnika u tijelu,
04:22
we thought of complicated things like estrogen and insulin,
91
262554
3170
razmišljali o kompleksnim stvarima poput estrogena i inzulina,
04:25
or nerve transmission.
92
265724
1470
ili o živčanom prijenosu.
04:27
Very complex processes with very complex chemicals
93
267194
3295
Vrlo složeni procesi, s vrlo složenim kemikalijama,
04:30
that fit into very complex receptors.
94
270489
2288
što se uklapaju u vrlo složene receptore.
04:32
And here's this incredibly simple molecule,
95
272777
2361
A ovdje je ta nevjerojatno jednostavna molekula,
04:35
a nitrogen and an oxygen that are stuck together,
96
275138
3338
spoj dušika i kisika,
04:38
and yet these are hugely important for [unclear] our low blood pressure,
97
278476
4630
no iznimno važna za snižavanje krvnog tlaka,
04:43
for neurotransmission, for many, many things,
98
283106
2606
za prijenos živčanih impulsa, za mnogo toga...
04:45
but particularly cardiovascular health.
99
285712
3402
Naročito za zdravlje krvožilnog sustava!
04:49
And I started doing research, and we found, very excitingly,
100
289114
3302
Započeo sam s istraživanjima, i otkrili smo - vrlo uzbudljivo! -
04:52
that the skin produces nitric oxide.
101
292416
2610
da koža proizvodi dušikov oksid.
04:55
So it's not just in the cardiovascular system it arises.
102
295026
2897
Dakle, ne pojavljuje se on samo u krvožilnom sustavu...
04:57
It arises in the skin.
103
297923
1867
Pojavljuje se u koži.
04:59
Well, having found that and published that,
104
299790
1866
Pošto smo to otkrili i objavili otkriće,
05:01
I thought, well, what's it doing?
105
301656
2056
pomislio sam: Dobro, a na što on utječe?
05:03
How do you have low blood pressure in your skin?
106
303712
1480
Kako postići nizak krvni tlak u koži?
05:05
It's not the heart. What do you do?
107
305192
2091
Ne radi se o srcu. Što učiniti?
05:07
So I went off to the States, as many people do if they're going to do research,
108
307283
4071
Otišao sam u SAD, kao i mnogi ljudi koji se kane baviti istraživanjima,
05:11
and I spent a few years in Pittsburgh. This is Pittsburgh.
109
311354
3737
i proveo sam nekoliko godina u Pittsburghu. Ovo je Pittsburgh.
05:15
And I was interested in these really complex systems.
110
315091
2613
Zanimali su me ovi doista složeni sustavi.
05:17
We thought that maybe nitric oxide affected cell death,
111
317704
4041
Pomislili smo da dušikov oksid možda utječe na umiranje stanica,
05:21
and how cells survive, and their resistance to other things.
112
321745
2480
i na preživljavanje stanica, i na njihovu otpornost na razne tvari.
05:24
And I first off started work in cell culture, growing cells,
113
324225
3367
Započeo sam raditi na staničnoj kulturi, na uzgoju stanica...
05:27
and then I was using knockout mouse models --
114
327592
2120
Potom sam koristio mišje "knockout" modele -
05:29
mice that couldn't make the gene.
115
329712
1737
miševe koji nisu mogli stvoriti gen...
05:31
We worked out a mechanism, which -- NO was helping cells survive.
116
331449
4410
Otkrili smo mehanizam prema kojemu dušikov oksid pomaže stanicama preživjeti.
05:35
And I then moved back to Edinburgh.
117
335859
3821
Onda sam se vratio u Edinburgh...
05:39
And in Edinburgh, the experimental animal we use is the medical student.
118
339680
2782
A u Edinburghu, kao "laboratorijskog miša" koristimo - studenta medicine.
05:42
It's a species close to human,
119
342462
2058
To je vrsta bliska ljudskoj,
05:44
with several advantages over mice:
120
344520
1902
s nekoliko prednosti u odnosu na miševe:
05:46
They're free, you don't shave them, they feed themselves,
121
346422
3456
besplatni su, nije ih potrebno brijati, sami se hrane,
05:49
and nobody pickets your office saying,
122
349878
2120
i nitko ne upada u vaš ured uz riječi:
05:51
"Save the lab medical student."
123
351998
2400
"Zaštitimo laboratorijskog studenta medicine!"
05:54
So they're really an ideal model.
124
354398
3263
Dakle, oni su stvarno idealni predlošci.
05:57
But what we found
125
357661
1961
Međutim, otkrili smo da
05:59
was that we couldn't reproduce in man the data we had shown in mice.
126
359622
4617
na čovjeku ne možemo ponoviti nalaze koje smo dobili na miševima.
06:04
It seemed we couldn't turn off the production
127
364239
3240
Čini se da nismo mogli isključiti proizvodnju
06:07
of nitric oxide in the skin of humans.
128
367479
3080
dušikovog oksida u koži ljudi.
06:10
We put on creams that blocked the enzyme that made it,
129
370559
2792
Stavljali smo kreme koje onemogućavaju enzim koji ga stvara,
06:13
we injected things. We couldn't turn off the nitric oxide.
130
373351
4384
ubrizgavali smo koješta. Nismo mogli isključiti dušikov oksid.
06:17
And the reason for this, it turned out, after two or three years' work,
131
377735
3264
Nakon dvije ili tri godine rada, ispostavilo se
06:20
was that in the skin we have huge stores
132
380999
4048
da u koži imamo ogromne zalihe -
06:25
not of nitric oxide, because nitric oxide is a gas,
133
385047
3088
ne dušikovog oksida, jer on je plin,
06:28
and it's released -- (Poof!) -- and in a few seconds it's away,
134
388135
3152
i pušten... puf!... nema ga za par sekundi,
06:31
but it can be turned into these forms of nitric oxide --
135
391287
3224
ali može se pretvoriti u oblike dušikovog oksida:
06:34
nitrate, NO3; nitrite, NO2; nitrosothiols.
136
394511
3632
nitrate (NO3), nitrite (NO2), nitrozotiole.
06:38
And these are more stable,
137
398143
1416
Oni su stabilniji.
06:39
and your skin has got really large stores of NO.
138
399559
4160
U našoj koži postoje uistinu velike zalihe dušikovog oksida.
06:43
And we then thought to ourselves, with those big stores,
139
403719
2825
Kad su već zalihe tolike, pitali smo se
06:46
I wonder if sunlight might activate those stores
140
406544
3311
može li ih Sunčeva svjetlost aktivirati
06:49
and release them from the skin,
141
409855
1744
i otpustiti ih iz kože
06:51
where the stores are about 10 times as big as what's in the circulation.
142
411599
3392
u kojoj su one i 10-ak puta veće od onih u krvotoku.
06:54
Could the sun activate those stores into the circulation,
143
414991
2840
Može li Sunce te zalihe potaknuti ka krvotoku,
06:57
and there in the circulation do its good things for your cardiovascular system?
144
417831
5240
i tako blagotvorno djelovati na krvožilni sustav?
07:03
Well, I'm an experimental dermatologist,
145
423071
2528
Kako sam ja eksperimentalni dermatolog,
07:05
so what we did was we thought
146
425599
1305
pomislili smo da ćemo
07:06
we'd have to expose our experimental animals to sunlight.
147
426904
3527
morati naše "pokusne kuniće" izlagati suncu.
07:10
And so what we did was we took a bunch of volunteers
148
430431
4080
Uzeli smo stoga hrpu dobrovoljaca
07:14
and we exposed them to ultraviolet light.
149
434511
2698
i izlagali ih ultraljubičastom svjetlu.
07:17
So these are kind of sunlamps.
150
437209
1729
To su, znači, svojevrsne solarne svjetiljke.
07:18
Now, what we were careful to do was,
151
438938
2696
Pritom smo vodili računa o tome
07:21
vitamin D is made by ultraviolet B rays
152
441634
2960
da ultraljubičaste B-zrake potiču stvaranje vitamina D,
07:24
and we wanted to separate our story from the vitamin D story.
153
444594
3976
a ovaj smo svoj rad željeli odvojiti od teme vitamina D.
07:28
So we used ultraviolet A, which doesn't make vitamin D.
154
448570
3847
Zato smo upotrebljavali ultraljubičaste A-zrake koje ne stvaraju vitamin D.
07:32
When we put people under a lamp
155
452417
2281
Kad smo ljude izložili zrakama svjetiljke
07:34
for the equivalent of about 30 minutes of sunshine in summer in Edinburgh,
156
454698
5076
onoliko koliko je istovjetno 30-minutnom ljetnom sunčanju u Edinburghu,
07:39
what we produced was, we produced a rise
157
459774
2540
izazvali smo porast
07:42
in circulating nitric oxide.
158
462314
1992
dušikovog oksida u krvi.
07:44
So we put patients with these subjects under the UV,
159
464306
2848
Onda smo uključili i pacijente i njih izlagali ultraljubičastim zrakama;
07:47
and their NO levels do go up,
160
467154
2416
količine dušikovog oksida su i kod njih rasle,
07:49
and their blood pressure goes down.
161
469570
2136
a krvni tlak je padao.
07:51
Not by much, as an individual level,
162
471706
2377
Na individualnoj razini ne suviše,
07:54
but enough at a population level
163
474083
2367
ali na razini populacije dovoljno
07:56
to shift the rates of heart disease in a whole population.
164
476450
3720
da utječe na učestalost srčanih bolesti u cijeloj populaciji.
08:00
And when we shone UV at them,
165
480170
2424
Kad smo ih obasjavali ultraljubičastim zrakama,
08:02
or when we warmed them up to the same level as the lamps,
166
482594
3662
ili kad smo ih zagrijavali do temperature svjetiljki,
08:06
but didn't actually let the rays hit the skin, this didn't happen.
167
486256
3262
ali smo onemogućili kontakt zraka i kože, to se nije dogodilo.
08:09
So this seems to be a feature of ultraviolet rays hitting the skin.
168
489518
3864
Dakle, čini se da samo sraz ultraljubičastih zraka i kože dovodi do takvog učinka.
08:13
Now, we're still collecting data.
169
493382
1824
Naravno, još prikupljamo podatke.
08:15
A few good things here:
170
495206
1448
Nekoliko je dobrih vijesti...
08:16
This appeared to be more marked in older people.
171
496654
3147
Čini se da je to izraženije kod starijih ljudi.
08:19
I'm not sure exactly how much.
172
499801
1613
Nisam siguran točno koliko.
08:21
One of the subjects here was my mother-in-law,
173
501414
1773
Jedna od ispitanika bila je i moja punica,
08:23
and clearly I do not know her age.
174
503187
2952
i, očito, ja ne znam koliko joj je godina.
08:26
But certainly in people older than my wife,
175
506139
3432
Ali, sigurno kod osoba starijih od moje supruge
08:29
this appears to be a more marked effect.
176
509571
3133
učinak se čini izrazitijim.
08:32
And the other thing I should mention
177
512704
1251
Moram napomenuti da
08:33
was there was no change in vitamin D.
178
513955
2056
nije bilo promjene u razini vitamina D.
08:36
This is separate from vitamin D.
179
516011
2120
Ovo nema veze s vitaminom D.
08:38
So vitamin D is good for you -- it stops rickets,
180
518131
1536
Dakle, vitamin D je dobar za vas - zaustavlja rahitis,
08:39
it prevents calcium metabolism, important stuff.
181
519667
2240
sprečava razgradnju kalcija, važnog elementa.
08:41
But this is a separate mechanism from vitamin D.
182
521907
3032
No, ovdje se radi o procesu različitom od onoga kod vitamina D.
08:44
Now, one of the problems with looking at blood pressure
183
524939
2576
Jedan od problema s krvnim tlakom je
08:47
is your body does everything it can
184
527515
1552
što tijelo čini sve što može
08:49
to keep your blood pressure at the same place.
185
529067
1583
da bi ga održalo.
08:50
If your leg is chopped off and you lose blood,
186
530650
1649
Ostanemo li bez noge i gubimo krv,
08:52
your body will clamp down, increase the heart rate,
187
532299
2905
tijelo će pooštriti kontrolu, ubrzati rad srca,
08:55
do everything it can to keep your blood pressure up.
188
535204
2224
učiniti sve što može kako bi održalo naš krvni tlak.
08:57
That is an absolutely fundamental physiological principle.
189
537428
2976
To je apsolutno temeljno fiziološko načelo.
09:00
So what we've next done
190
540404
1807
Potom smo proučavali
09:02
is we've moved on to looking at blood vessel dilatation.
191
542211
3656
širenje krvnih žila.
09:05
So we've measured -- this is again,
192
545867
1497
Mjerili smo... ovo je ponovno...
09:07
notice no tail and hairless, this is a medical student.
193
547364
5328
vidite ćelavoga i bez repa, studenta medicine.
09:12
In the arm, you can measure blood flow in the arm
194
552692
2618
Protok krvi u ruci moguće je izmjeriti
09:15
by how much it swells up as some blood flows into it.
195
555310
3232
po tome koliko ruka nabrekne uslijed dotoka krvi.
09:18
And what we've shown is that doing a sham irradiation --
196
558542
3475
Pokazali smo da lažno ozračivanje -
09:22
this is the thick line here --
197
562017
1469
to je ova debela crta ovdje -
09:23
this is shining UV on the arm so it warms up
198
563486
2400
ovo je ultraljubičasto ozračivanje ruke, kojime ju se zagrijava,
09:25
but keeping it covered so the rays don't hit the skin.
199
565886
2824
ali zrake ne dopiru do kože, jer je pokrivena.
09:28
There is no change in blood flow, in dilatation of the blood vessels.
200
568710
3912
Nema promjena u protoku krvi, niti u širenju krvnih žila.
09:32
But the active irradiation,
201
572622
1849
Međutim, pri aktivnom ozračivanju
09:34
during the UV and for an hour after it,
202
574471
3352
ultraljubičastim zrakama i sat vremena nakon njega,
09:37
there is dilation of the blood vessels.
203
577823
2097
vidljivo je proširivanje krvnih žila.
09:39
This is the mechanism by which you lower blood pressure,
204
579920
2600
Na ovaj se način može sniziti krvni tlak,
09:42
by which you dilate the coronary arteries also,
205
582520
2376
čime se proširuju i srčane arterije,
09:44
to let the blood be supplied with the heart.
206
584896
1711
što srcu olakšava potiskivanje krvi u tijelo.
09:46
So here, further data that ultraviolet -- that's sunlight --
207
586607
4393
Ovo je daljnja potvrda da ultraljubičaste zrake, tj. Sunčeva svjetlost,
09:51
has benefits on the blood flow and the cardiovascular system.
208
591000
4879
imaju blagotvoran učinak na protok krvi i na krvožilni sustav.
09:55
So we thought we'd just kind of model --
209
595879
2343
Odlučili smo uobličiti u model
09:58
Different amounts of UV hit different parts of the Earth at different times of year,
210
598222
6249
različite količine UV-zračenja, na različitim dijelovima Zemlje, u različita doba godine.
10:04
so you can actually work out those stores of nitric oxide --
211
604471
4024
Tako je moguće izračunati zalihe dušikovog oksida -
10:08
the nitrates, nitrites, nitrosothiols in the skin --
212
608495
2256
nitrate, nitrite, nitrozotiole u koži -
10:10
cleave to release NO.
213
610751
2872
koji cijepanjem oslobađaju dušikov oksid.
10:13
Different wavelengths of light have different activities of doing that.
214
613623
3825
Različite svjetlosne valne duljine imaju pritom različite uloge.
10:17
So you can look at the wavelengths of light that do that.
215
617448
2079
Stoga možemo promatrati koje svjetlosne valne duljine što čine.
10:19
And you can look -- So, if you live on the equator, the sun comes straight overhead,
216
619527
3985
Dakle, ako živimo na ekvatoru, Sunce je točno iznad naših glava;
10:23
it comes through a very thin bit of atmosphere.
217
623512
1816
probija se kroz vrlo tanak sloj atmosfere.
10:25
In winter or summer, it's the same amount of light.
218
625328
2439
I zimi i ljeti, to je ista količina svjetla.
10:27
If you live up here, in summer
219
627767
2513
Živimo li ovdje,
10:30
the sun is coming fairly directly down,
220
630280
2656
ljeti sunce pada prilično izravno,
10:32
but in winter it's coming through a huge amount of atmosphere,
221
632936
3307
ali zimi se probija kroz ogromne slojeve atmosfere,
10:36
and much of the ultraviolet is weeded out,
222
636243
3221
i mnogo se ultraljubičastih zraka gubi,
10:39
and the range of wavelengths that hit the Earth
223
639464
2352
a raspon valnih duljina koje dolaze do Zemlje
10:41
are different from summer to winter.
224
641816
2328
se od ljeta do zime razlikuje.
10:44
So what you can do is you can multiply those data
225
644144
1942
Dakle, možemo pomnožiti te podatke
10:46
by the NO that's released
226
646086
1993
s oslobođenim dušikovim oksidom
10:48
and you can calculate how much nitric oxide
227
648079
3184
i izračunati koliko će dušikovog oksida
10:51
would be released from the skin into the circulation.
228
651263
3169
biti iz kože otpušteno u krvotok.
10:54
Now, if you're on the equator here --
229
654432
2000
Nalazimo li se na ekvatoru -
10:56
that's these two lines here, the red line and the purple line --
230
656432
3427
to su ove dvije crte ovdje, crvena i ljubičasta -
10:59
the amount of nitric oxide that's released is the area under the curve,
231
659859
4397
količina oslobođenog dušikovog oksida odgovara površini ispod krivulje,
11:04
it's the area in this space here.
232
664256
2031
površini u ovom području ovdje.
11:06
So if you're on the equator, December or June,
233
666287
2697
Dakle, nađemo li se na ekvatoru, u prosincu ili u lipnju,
11:08
you've got masses of NO being released from the skin.
234
668984
3256
koža će otpuštati gomile dušikovog oksida.
11:12
So Ventura is in southern California.
235
672240
2464
Ventura se nalazi u južnoj Kaliforniji.
11:14
In summer, you might as well be at the equator.
236
674704
2216
Ljeti bi nam jednako bilo i na ekvatoru.
11:16
It's great. Lots of NO is released.
237
676920
2056
Sjajno je ondje! Oslobađaju se ogromne količine dušikovog oksida.
11:18
Ventura mid-winter, well, there's still a decent amount.
238
678976
3943
Ventura usred zime? Još je uvijek zamjetna pristojna količina.
11:22
Edinburgh in summer, the area beneath the curve is pretty good,
239
682919
3961
Edinburgh ljeti? Površina ispod krivulje je zadovoljavajuća.
11:26
but Edinburgh in winter, the amount of NO that can be released
240
686880
4215
Ali, Edinburgh zimi? Količina oslobođenog dušikovog oksida
11:31
is next to nothing, tiny amounts.
241
691095
3858
gotovo je nikakva, neznatna.
11:34
So what do we think?
242
694953
1805
Dakle, što mi mislimo?
11:36
We're still working at this story,
243
696758
1592
Još uvijek na ovome radimo,
11:38
we're still developing it, we're still expanding it.
244
698350
1912
još uvijek razvijamo model, proširujemo ga.
11:40
We think it's very important.
245
700262
1648
Smatramo ovo vrlo važnim!
11:41
We think it probably accounts for a lot of the north-south health divide within Britain,
246
701910
3593
Ovo vjerojatno uvelike objašnjava zdravstvene razlike između britanskog sjevera i juga.
11:45
It's of relevance to us.
247
705503
1631
Ovo je i za nas važno!
11:47
We think that the skin --
248
707134
1688
Mislimo da koža...
11:48
well, we know that the skin has got very large stores
249
708822
2888
Dobro, znamo da koža sadrži vrlo velike zalihe
11:51
of nitric oxide as these various other forms.
250
711710
2224
dušikovog oksida u svim tim različitim drugim oblicima.
11:53
We suspect a lot of these come from diet,
251
713934
1873
Pretpostavljamo da je za mnoge zaslužna prehrana -
11:55
green leafy vegetables, beetroot, lettuce
252
715807
2271
zeleno lisnato povrće, cikla ili zelena salata
11:58
has a lot of these nitric oxides that we think go to the skin.
253
718078
3320
bogati su dušikovim oksidima za koje vjerujemo da odlaze u kožu.
12:01
We think they're then stored in the skin,
254
721398
2144
Potom se pohranjuju u koži,
12:03
and we think the sunlight releases this
255
723542
2400
i mislimo da ih Sunčeva svjetlost oslobađa
12:05
where it has generally beneficial effects.
256
725942
2633
što, općenito, ima korisne učinke.
12:08
And this is ongoing work, but dermatologists --
257
728575
2479
Puno je još posla pred nama, ali dermatolozi...
12:11
I mean, I'm a dermatologist.
258
731054
1720
Želim reći, ja sam dermatolog.
12:12
My day job is saying to people, "You've got skin cancer,
259
732774
2528
Moj svakodnevni posao je govoriti ljudima: "Imate rak kože;
12:15
it's caused by sunlight, don't go in the sun."
260
735302
1880
uzrokovan je suncem; ne izlazite na sunce..."
12:17
I actually think a far more important message
261
737182
2736
A mislim da je, zapravo, daleko važnija poruka
12:19
is that there are benefits as well as risks to sunlight.
262
739918
3424
da se u sunčevoj svjetlosti kriju i blagodati, kao i opasnosti.
12:23
Yes, sunlight is the major alterable risk factor for skin cancer,
263
743342
5753
Da, Sunčeva svjetlost je glavni promjenljiv rizični uzročnik raka kože,
12:29
but deaths from heart disease are a hundred times higher
264
749095
2871
ali smrtnost oboljelih od srčanih bolesti stoput je veća
12:31
than deaths from skin cancer.
265
751966
1952
od smrtnosti uslijed raka kože.
12:33
And I think that we need to be more aware of,
266
753918
2649
Mislim da moramo biti oprezniji,
12:36
and we need to find the risk-benefit ratio.
267
756567
2079
i da trebamo naći pravu mjeru opasnosti i blagodati.
12:38
How much sunlight is safe,
268
758646
1472
Koliko se smijemo izlagati suncu,
12:40
and how can we finesse this best for our general health?
269
760118
4200
i kako ga možemo najbolje iskoristiti za svoje zdravlje?
12:44
So, thank you very much indeed.
270
764318
2180
Hvala vam najljepša, doista!
12:46
(Applause)
271
766498
6897
(Pljesak)
O ovoj web stranici

Ova stranica će vas upoznati s YouTube videozapisima koji su korisni za učenje engleskog jezika. Vidjet ćete lekcije engleskog koje vode vrhunski profesori iz cijelog svijeta. Dvaput kliknite na engleske titlove prikazane na svakoj video stranici da biste reproducirali video s tog mjesta. Titlovi se pomiču sinkronizirano s reprodukcijom videozapisa. Ako imate bilo kakvih komentara ili zahtjeva, obratite nam se putem ovog obrasca za kontakt.

https://forms.gle/WvT1wiN1qDtmnspy7