Category Archives: Science

Cancer Risks From Our Food

comic showing the dangers of drawing false conclusion based on statistical significance

Randall Munroe illustrates RA Fisher’s point that you must think to draw reasonable conclusions from data. Click the image to see the full xkcd comic.

Pretty much everything you eat is associated with cancer. Don’t worry about it. by Sarah Kliff

The changes in cancer risk were all over the map: 39 percent found an increased risk, 33 percent found a decreased risk and 23 percent showed no clear evidence either way.
…
The vast majority of those studies, Schoenfeld and Ioannidis found, showed really weak associations between the ingredient at hand and cancer risk. A full 80 percent of the studies had shown statistical relationships that were “weak or nominally significant,” as measured by the study’s P-values. Seventy-five percent of the studies purporting to show a higher cancer risk fell into this category, as did 76 percent of those showing a lower cancer risk.

Sadly the evidence is often not very compelling but creates uncertainly in the public. Poorly communicated results and scientific illiteracy (both from publishers and the public) leads to more confusion than is necessary. Even with well done studies, good communication and a scientifically literate population nutrition and human health conclusion are more often questionable than they are clear.

Drug Company Funding Taints Published Medical Research

Science provide the opportunity for us to achieve great benefits for society. However, especially in medical research money can make what are already very difficult judgments even less reliable. Add that to a very poor understanding of science in those we elect and you have a dangerous combination. That combination is one of the largest risks we face and need to manage better. I wish we would elect people with a less pitiful appreciation for science but that doesn’t seem likely. That makes doing a better job of managing the conflicts of interest money puts into our current medical research a top priority.

How Drug Company Money Is Undermining Science by Charles Seife

In the past few years the pharmaceutical industry has come up with many ways to funnel large sums of money—enough sometimes to put a child through college—into the pockets of independent medical researchers who are doing work that bears, directly or indirectly, on the drugs these firms are making and marketing. The problem is not just with the drug companies and the researchers but with the whole system—the granting institutions, the research labs, the journals, the professional societies, and so forth. No one is providing the checks and balances necessary to avoid conflicts.
…
Peer-reviewed journals are littered with studies showing how drug industry money is subtly undermining scientific objectivity. A 2009 study in Cancer showed that participants somehow survived longer when a study’s authors had conflicts of interest than when the authors were clean. A 1998 study in the New England Journal of Medicine found a “strong association” between researchers’ conclusions about the safety of calcium channel blockers, a class of drugs used to reduce blood pressure, and their financial relationships with the firms producing the drugs.

Most of those in the system have an interest in minimizing an effort to clean this up. It is just more work they don’t want to do. Or it goes directly against their interest (drug companies that want to achieve favorable opinions by buying influence). The main political message in the USA for a couple decades has been to reduce regulation. Allowing research that is tainted because you find regulation politically undesirable is a bad idea. People that understand science and how complex medical research is appreciate this.

Sadly when we elect people that by and large are scientifically illiterate they don’t understand the risks of the dangerous practices they allow. Even if they were scientifically illiterate but understood their ignorance they could do a decent job by getting scientific consultation from experts but they don’t (to an extent they listen to the scientists that those that give them lots of money tell them to which does help make sure those giving the politicians cash have their interests served but it is not a good way to create policy with the necessary scientific thinking needed today).

How Caffeine Affects Your Body

From the video by Alex Dainis: Caffeine prevents adenosine from slowing down your nervous system, by binding to the same receptors adenosine would. Caffeine also stimulates the production of adrenaline. And it increases the amount of dopamine present. The average half life of caffeine in the human body is about 6 hours.

I have been curious about the caffeine content of various drinks and writing this post is a good enough reason to actually look it up.

expresso (2oz) 100 mg (varies – 60 mg to 180 mg)
coffee (8oz) 100 mg – this can vary quite a bit, 50 to over 100 mg is common. Brewed coffee has more caffeine 100-200 mg.
Red Bull (8.2 oz) 80 mg
tea (8oz) 20 to 80 mg (depending on strength and type, can also be higher, green tea is on the lower end)
Mountain Dew (12 oz) 54 mg (diet has 54 mg also)
Diet Coke 46 mg (regular Coke 34mg)
Pepsi 38 mg, Diet Pepsi 36 mg

Sprite, 7Up and some root beers have no caffeine.
Chocolate can also be a significant source of caffeine – dark chocolate can have over 80 mg per 100 g (approximately 4 ounces).

Smoking Bans at Work and Public Places Result in Significant Drops in Hospitalization for Heart Attacks, Strokes and Asthma.

Laws that end smoking at work and other public places result in significantly fewer hospitalizations for heart attacks, strokes, asthma and other respiratory conditions, a new UCSF analysis has found.

The research provides evidence that smoke-free laws that cover workplaces, restaurants and bars have the biggest impacts on hospitalizations, reduce health care costs and also raise quality of life, the researchers said. The research is published in closed science journal; for an “association” (when you act as though your focus is just growing your income I have trouble seeing the claim for being an association as legitimate) to do that is particularly pitiful. Adding to the sad commentary on the lack of respect for open scient this is research done by a “public” university with grants from the federal government. So sad how little some that should care about science do when it conflicts with their outdated notions of how to publicize research. We really should not tolerate such behavior.

“The public, health professionals, and policy makers need to understand that including exemptions and loopholes in legislation — such as exempting casinos — condemns more people to end up in emergency rooms,” said senior author Stanton A. Glantz, UCSF professor of medicine and director of the Center for Tobacco Control Research and Education at UCSF. “These unnecessary hospitalizations are the real cost of failing to enact comprehensive smoke-free legislation,” he said.

The inquiry consisted of a meta-analysis of 45 studies published prior to Nov. 30, 2011. Altogether, the research covered 33 different smoke-free-laws in cities and states around the United States as well as several countries, including New Zealand and Germany. The laws variously prohibit smoking in such public spots as restaurants, bars, and the workplace.

The authors found that comprehensive smoke-free laws were followed rapidly by significantly lower rates of hospital admissions than before the laws went into force:

A 15% drop in heart attack hospitalizations;
A 16% drop in stroke hospitalizations;
A 24% drop in hospitalizations for respiratory diseases including asthma and chronic obstructive pulmonary disease.

Continue reading →

Cancer Cells in Blind Mole Rats ‘commit suicide’

Cancer cells in blind mole rats ‘commit suicide’

Blind mole rats don’t get cancer, and geneticists have worked out why — their cells kill themselves with a poisonous protein when they multiply too much.

Blind mole rats, which live in underground burrows throughout Southern and Eastern Africa, and the Middle East, are fascinating creatures. The naked mole rat, in particular, is the only cold-blooded mammal known to man, doesn’t experience pain, and is also arguably the only mammal (along with the Damaraland mole rat) to demonstrate eusociality — that is, they live in large hierarchical communities with a queen and workers, like ants or bees.

They’re also cancer-proof, which was found in 2011 to be down to a gene that stops cancerous cells from forming. The same team thought that two other cancer-proof mole rat species might have similar genes, but instead it turns out that they do develop cancerous cells — it’s just that those cells are programmed to destroy themselves if they become dangerous.

Very interesting research. The results of evolution are amazing. And while turning the medical research discoveries into workable treatments for people is very difficult the continued increase in our knowledge helps us find treatments that work.

Evolution Follows a Predictable Genetic Pattern

Far from random, evolution follows a predictable genetic pattern

The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence — they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.

Though separated by 300 million years of evolution, these diverse insects — which include beetles, butterflies and aphids — experienced changes to a key protein called sodium-potassium adenosine triphosphatase, or the sodium-potassium pump, which regulates a cell’s crucial sodium-to-potassium ratio. The protein in these insects eventually evolved a resistance to cardenolides, which usually cripple the protein’s ability to “pump” potassium into cells and excess sodium out.
…
Andolfatto and his co-authors examined the sodium-potassium pump protein because of its well-known sensitivity to cardenolides. In order to function properly in a wide variety of physiological contexts, cells must be able to control levels of potassium and sodium. Situated on the cell membrane, the protein generates a desired potassium to sodium ratio by “pumping” three sodium atoms out of the cell for every two potassium atoms it brings in.

Cardenolides disrupt the exchange of potassium and sodium, essentially shutting down the protein, Andolfatto said. The human genome contains four copies of the pump protein, and it is a candidate gene for a number of human genetic disorders, including salt-sensitive hypertension and migraines. In addition, humans have long used low doses of cardenolides medicinally for purposes such as controlling heart arrhythmia and congestive heart failure.

Cool stuff. It makes sense to me which is nice (it is nice to get confirmation that I find what actually exists is sensible). When things that are true just seem crazy it is a bit disconcerting – like quantum mechanics. It is fun to read stuff that totally shakes up preconceived notions, but even then it is nice once I think understand it to find it sensible.

Does Diet Soda Result in Weight Gain?

Most of us want medical studies to provide clearer (more certain, more specific, more universal) indications than they actually provide. The conclusion of medical studies are often very clouded. Each person has a myriad of complex factors effecting how nutrition, activity and medication will affect us. Certain general conclusion can be drawn but it is very complex and difficult to universally state without various equivocations.

Advice For Diet Soda Lovers: Skip The Chips

Researchers at the University of North Carolina-Chapel Hill found that diet soda drinkers who ate a so-called “prudent” diet, rich in fruit, fish, vegetables, whole grains, nuts and milk, were significantly less likely to develop metabolic syndrome over 20 years than those who ate a “Western diet” heavy in fried foods, meats and sugars.

Metabolic syndrome is a condition characterized by excess abdominal fat, elevated blood sugar, high blood pressure, elevated triglycerides and low HDL cholesterol. About 32 percent of the participants in the “Western diet” cluster developed the condition.

The question of whether diet soda truly helps people manage their weight turns out to be a very tough one to answer.

Conflicting findings abound. A large study published in the New England Journal of Medcine last year found that diet soda had no effect on weight. But another one, published in 2008, found that drinking more than three diet drinks a day led to weight gain.

I would like to know, with much greater certainty what nutritional and food related advice I need to consider when making my choices. To a significant degree I think there is going to be quite a bit of uncertainty (much more than we want) for at least the next 30 years (projecting far out into the future with any accuracy seems very difficult to me.

I am skeptical of purely correlational results. You can try to have similar subsets of people but that is actually hard and if you allow for similar groups and then let the choose something (like diet sodas or not) the chance of that actually being a significant choice that results in many other decisions being different between the subgroups seems a big risk (that makes accepting the correlation as evidence as risky). When you have a scientific explanation it makes the evidence much more compelling, but it is also easy to be taken in by explanations meant to fit the results of a study.

I can believe diet soda can do some bad things to your health. I believe if you are trying to reduce your weight by reducing calories drinking diet soda in place of sugary soda is a big help. I can believe drinking water instead of diet soda would be even better. I want caffeine and don’t like coffee. I have cut down drinking Mountain Dew to less than 2 a week. I have substituted diet soda over the last year. I am not sure that is the right choice, but it is the one I have made so far.

Medical Studies Showing Largest Benefits Often Prove to be False

There is another study showing the results of health studies often are proven false. Medical studies with striking results often prove false

If a medical study seems too good to be true, it probably is, according to a new analysis.

In a statistical analysis of nearly 230,000 trials compiled from a variety of disciplines, study results that claimed a “very large effect” rarely held up when other research teams tried to replicate them.
…
The report should remind patients, physicians and policymakers not to give too much credence to small, early studies that show huge treatment effects, Ioannidis said.

The Stanford professor chose to publish this paper in a closed science publication. But previously he published openly on: Why Most Published Research Findings Are False.

Nobel Prize in Physiology or Medicine 2012 for Reprogramming Cells to be Pluripotent

The Nobel Prize in Physiology or Medicine 2012 was awarded “for the discovery that mature cells can be reprogrammed to become pluripotent.” The prize goes jointly to Sir John B. Gurdon, Gurdon Institute in Cambridge, UK and Shinya Yamanaka, Kyoto University (he is also a senior investigator at the Gladstone Institutes in the USA).

The Nobel Prize recognizes two scientists who discovered that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body. Their findings have revolutionised our understanding of how cells and organisms develop.

John B. Gurdon discovered (in 1962) that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.

Shinya Yamanaka discovered more than 40 years later, in 2006, how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could reprogram mature cells to become pluripotent stem cells, i.e. immature cells that are able to develop into all types of cells in the body.

These groundbreaking discoveries have completely changed our view of the development and cellular specialisation. We now understand that the mature cell does not have to be confined forever to its specialised state. Textbooks have been rewritten and new research fields have been established. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy.

All of us developed from fertilized egg cells. During the first days after conception, the embryo consists of immature cells, each of which is capable of developing into all the cell types that form the adult organism. Such cells are called pluripotent stem cells. With further development of the embryo, these cells give rise to nerve cells, muscle cells, liver cells and all other cell types – each of them specialised to carry out a specific task in the adult body. This journey from immature to specialised cell was previously considered to be unidirectional. It was thought that the cell changes in such a way during maturation that it would no longer be possible for it to return to an immature, pluripotent stage.

Continue reading →

Why is the Sky Dark at Night?

The answer isn’t quite as simple as it seems. I find the wording in the video a bit confusing.

The point I believe, is that the sky is dark instead of light. But not that the brightness would be huge (so for example, you couldn’t necessarily read my book outside just by starlight). The light would be very faint, it is just that it would be lightish instead of blackish, due to the reasons explained (redshift etc.). At least that is my understanding.