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Smoking “causes hundreds of DNA changes”

bbc.com

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Re: Smoking “causes hundreds of DNA changes”

#171

Post by vibrio »

adrianN wrote: post #107
vibrio wrote: post #93

Earlier quoted context omitted.

You could get a 'super T cell' that behaves just as you want, or as is empirically observed, mutations would more commonly lead to leukemia. There is a phenomenon call somatic hypermuatation, that as T-cell respond to antigens, they 'get sloppy' in coding their DNA to optimize the response. It' has also been linked to blood cancers, so it is a risky approach, like many aspects of immunity.

Of course almost all mutations won't be beneficial (this is also true of germline mutations). But "can only be harmful" seems to imply that beneficial mutations are impossible.

agreed. sort of my point: some changes can be beneficial, but the process is very risky and the cell goes through great measures to minimize any sequence changes. some viruses are sloppy on purpose, as they have tens or hundreds of thousands of offspring, so trial and error is acceptable.

Re: Smoking “causes hundreds of DNA changes”

#172

Post by nonbel »

QuantumRoar wrote: post #163
nonbel wrote: post #141

Earlier quoted context omitted.

"I don't see how your explanation could enable anything but a statistical model." First, I wouldn't call Armitage and Doll a "statistical model", it is more a "rational model" derived from first principle considerations. "Statistical models" are stuff like linear regressions, at least to me. Second, my explanation is useful in that if it is correct, we would need a certain combination of division and error rates to e…

First, from Wikipedia [1]: "The Armitage–Doll model is a statistical model of carcinogenesis [...]" Second, the paper itself [2] talks about cancer rates and uses experimental data for it (I just glossed over it, so I can't give a decent summary). This is a statistical model. I think we disagree since you misunderstand what the term statistical model means. Furthermore, you are misusing the term "first principles." F…

1) The original implementation of the Armitage-Doll model contains simplifications made for computational reasons that mess it up. You can easily see this by checking that the probability of a mutation per cell goes over one (see eq 1 in the appendix of Armitage and Doll 1954). Check the link to my earlier discussion on this site for the corrected version. BTW, I also see some discussion of Armitage & Doll in the appendix of the current Alexandrov et al. (2016) paper (they use the simplified version of the model).

2) Every model is originally based on some kind of observation. The Armitage-Doll model is basically "cancer is caused by the accumulation of errors in a single cell", then they go on and do the math from there. Sure, it would be great to know exactly what those errors are, how many it takes, which cells, etc so that we can constrain all the parameters. You are saying that "from first principles" precludes having any parameters, either free or determined by data?

3) As I said, I think the above is quite different from a statistical model like y = a +b*x + eps. Note: In some cases you can deduce an equation like that from an idea like Armitage-Doll, which is fine. Armitage-Doll definitely has more content to it.

Re: Smoking “causes hundreds of DNA changes”

#173

Post by hfsktr »

Raphmedia wrote: post #145
zymhan wrote: post #131

Earlier quoted context omitted.

Would organic tobacco avoid the issue of Polonium then?

The safest way possible to smoke tobacco is to grow it yourself. The small yields will limit you to smoking only a few time a month. You will want to taste that homegrown tobacco so you will most likely invest in a good old wooden pipe. This will make it so that you don't inhale the smoke into your lungs. You will however still be at risk of mouth and throat cancer.

How would using a pipe prevent you from inhaling the smoke?

I have never used one (but I was always curious when I smoked) so maybe it's a silly question.

Re: Smoking “causes hundreds of DNA changes”

#174

Post by evilduck »

tluyben2 wrote: post #79
ommunist wrote: post #63

Earlier quoted context omitted.

And surprisingly no mass deaths from cancer of Russians or Irish were detected, with both nations famous for alcohol abuse. Yes, alcohol is harmful, but like Russians joke, it only kills weak brain cells.

Maybe a lot of people die before they get cancer from it? Like organ failure (liver, kidney, heart) way before they develop cancer (symptoms)? Or get into accidents (car, freezing to death) etc. It is like people saying smoking can prevent Alzheimer as statistically people who smoke a lot have less instances of it. Because they die from that habit before the Alzheimer shows up.

OTOH moderate intake of alcohol, despite the risks, also has positive effects on the cardiovascular system. Wine has antioxidants which are associated with longevity, beer is good for bone strength, and so on. While an alcoholic may have a higher chance of dying before cancer gets them due to organ failure and accidents, a glass-of-wine-a-day drinker might live longer with a higher quality of life with the increased cancer risks than they otherwise might have with their congenital heart disease or whatever. Cancer typically gets you when you're old, heart disease gets a lot of people in their 40s and 50s.

And while the first world doesn't benefit directly anymore, typical brewing and fermenting processes ensured a drink was sanitary due to lengthy boiling times or yeast out-competing other microbes. Alcohol and hops/flavorings provide antimicrobial effects, acetobacter competed and inhibited against other water-born bacterial and mold growth. Alcoholic beverages are an easy way to store and preserve calories in times of scarcity, etc. It's quite likely that those who chose low-alcohol beverages were saved from other water-born diseases and lived longer thanks to it.

Re: Smoking “causes hundreds of DNA changes”

#175

Post by hfourm »

roflchoppa wrote: post #139
Shivetya wrote: post #35

while there are some studies that do not put marijuana smoking as high on the danger list [1] I am really curious that as legalization increases what will we see in the future. Then of course there is the loosely regulated area of vaping and who knows what is in some of those fluids. For the most part I am quite sure they have to be safer than smoking but I would love some hard regulation. 2005 study on marijuana smo…

Yeah my buddy has been thinking about moving over to just vaporizing marijuana, opposed to smoking it in papers. Might as well remove what you can?

I think it ultimately comes down to the vaporization tool. Older brands and vaporization techniques used by things like the Volcano or Silver Surfer, I would consider pretty safe. But once you get into the lower budget vaporizers, e-cigs, wax on metal coils, I think it gets more sketchy and its harder for the consumer to determine quality

Re: Smoking “causes hundreds of DNA changes”

#177

Post by pessimizer »

zeveb wrote: post #134
quesera wrote: post #99

Earlier quoted context omitted.

Chewing tobacco does bad things.

I wonder if that's due to the other stuff typically added to chewing tobacco. It'd be interesting if tobacco could be safer, but isn't, because the manufacturers don't want to incur the expense and anti-tobacco folks want to keep people from smoking at all, not make it safer (c.f. vaping, which is — I think — basically harmless and yet is banned as much as smoking is).

It's based on roasting/burning it, the same reason why meat is cancer-causing. That's also why Swedish snus probably isn't cancer causing, because instead of being roasted, the tobacco is steam pasteurized.

I can't imagine that cigarettes would work with steamed leaves.

edit: And you'd have to vape the steamed leaf cigarettes, of course.

Re: Smoking “causes hundreds of DNA changes”

#178

Post by rubicon33 »

nonbel wrote: post #92

>'Prof Stratton said in these organs smoking seemed to be accelerating a natural mutational process, but how it did this was "mysterious and complex".' Wow, just wow. This is standard Armitage & Doll model that has been taught since the 1950s. Every time a cell divides there is some chance of a genetic error occurring. The more generations away from the zygote a cell is, the more genetic errors it will have accumulat…

'Every time a cell divides there is some chance of a genetic error occurring.'

Why is that cell allowed to exist then? Isn't there a quality control mechanism or something, that can detect an error occurred and delete the cell?

Re: Smoking “causes hundreds of DNA changes”

#179

Post by kamaal »

phonon wrote: post #167
payamb wrote: post #128

Earlier quoted context omitted.

I've stopped smoking a week ago and brain fog is killing me, I'm not able to do my job any more, any advice ? I just sit and stare at monitor without my brain working :/

Nicotine gum? The danger is in the smoking, not the addictive substance.

Smoking breaks are a social activity in many workplaces.

Its hard to get rid of those sort of addictions.

Re: Smoking “causes hundreds of DNA changes”

#180

Post by pessimizer »

striking wrote: post #151
zeveb wrote: post #134

Earlier quoted context omitted.

I wonder if that's due to the other stuff typically added to chewing tobacco. It'd be interesting if tobacco could be safer, but isn't, because the manufacturers don't want to incur the expense and anti-tobacco folks want to keep people from smoking at all, not make it safer (c.f. vaping, which is — I think — basically harmless and yet is banned as much as smoking is).

According to the American Cancer Society: > The most harmful cancer-causing substances in smokeless tobacco are tobacco-specific nitrosamines. > Cancers linked to the use of smokeless tobacco include: * Mouth, tongue, cheek, and gum cancer * Cancer in the esophagus * Pancreatic cancer You can also get other kinds of mouth and tooth problems, and of course nicotine is still a definite health risk. If there were a way…

None of these are true for snus, and the American Cancer Society hasn't been the most trustworthy party on tobacco (although they should be.)

https://scholar.google.com/scholar?q=swedish%20snus

The Lancet article is good, but there's a universal consensus.

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