Tag Archives: Life Science

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).

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.

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 →

Key Indicator for Malignant Melanoma Found

Skin cancer detection breakthrough

The researchers found that certain biochemical elements in the DNA of normal pigment-producing skin cells and benign mole cells are absent in melanoma cells. Loss of these methyl groups — known as 5-hmC — in skin cells serves as a key indicator for malignant melanoma. Loss corresponded to more-advanced stages of melanoma as well as clinical outcome.

Strikingly, researchers were able to reverse melanoma growth in preclinical studies. When the researchers introduced enzymes responsible for 5-hmC formation to melanoma cells lacking the biochemical element, they saw that the cells stopped growing.

“It is difficult to repair the mutations in the actual DNA sequence that are believed to cause cancer,” said Christine Lian, a physician-scientist in the Department of Pathology at BWH and one of the lead authors. “So having discovered that we can reverse tumor cell growth by potentially repairing a biochemical defect that exists — not within the sequence but just outside of it on the DNA structure — provides a promising new melanoma treatment approach for the medical community to explore.”

Because cancer is traditionally regarded as a genetic disease involving permanent defects that directly affect the DNA sequence, this new finding of a potentially reversible abnormality that surrounds the DNA (thus termed “epigenetic”) is a hot topic in cancer research, according to the researchers.

In the United States, melanoma is the fifth most common type of new cancer diagnosis in men and the seventh most common type in women. The National Cancer Institute estimates that in 2012 there will be 76,250 new cases and 9,180 deaths in the United States owing to melanoma.

Thankfully scientists keep making great progress in understanding and finding potential clues to treating cancer. And big gains have been made in treating some cancers over the last few decades. But the research successes remain difficult to turn into effective solutions in treating patients.

I am thankful we have so many scientists doing good work in this difficult and important area (cancer).

Should Giant Viruses Be Included on the Tree of Life?

A new study of giant viruses supports the idea that viruses are ancient living organisms and not inanimate molecular remnants. The study may reshape the universal family tree, adding a fourth major branch to the three that most scientists agree represent the fundamental domains of life. But I am not sure that makes sense. The reason given for viruses not being “life” is that they cannot reproduce themselves – they hijack living cells to reproduce. The research in the past history of viruses as they evolved into current viruses is interesting but I don’t see the reason to classify current viruses as life.

The researchers used a relatively new method to peer into the distant past. Rather than comparing genetic sequences, which are unstable and change rapidly over time, they looked for evidence of past events in the three-dimensional, structural domains of proteins. These structural motifs, called folds, are relatively stable molecular fossils that – like the fossils of human or animal bones – offer clues to ancient evolutionary events, said University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-AnollÃ©s, who led the analysis.

“Just like paleontologists, we look at the parts of the system and how they change over time,” Caetano-AnollÃ©s said. Some protein folds appear only in one group or in a subset of organisms, he said, while others are common to all organisms studied so far.

“We make a very basic assumption that structures that appear more often and in more groups are the most ancient structures,” he said.

Most efforts to document the relatedness of all living things have left viruses out of the equation, Caetano-AnollÃ©s said.

“We’ve always been looking at the Last Universal Common Ancestor by comparing cells,” he said. “We never added viruses. So we put viruses in the mix to see where these viruses came from.”

The researchers conducted a census of all the protein folds occurring in more than 1,000 organisms representing bacteria, viruses, the microbes known as archaea, and all other living things. The researchers included giant viruses because these viruses are large and complex, with genomes that rival – and in some cases exceed – the genetic endowments of the simplest bacteria, Caetano-AnollÃ©s said.

Open access paper: Giant Viruses Coexisted With the Cellular Ancestors and Represent a Distinct Supergroup Along With Superkingdoms Archaea, Bacteria and Eukarya

The discovery of giant viruses with genome and physical size comparable to cellular organisms, remnants of protein translation machinery and virus-specific parasites (virophages) have raised intriguing questions about their origin. Evidence advocates for their inclusion into global phylogenomic studies and their consideration as a distinct and ancient form of life.
…
Results call for a change in the way viruses are perceived. They likely represent a distinct form of life that either predated or coexisted with the last universal common ancestor (LUCA) and constitute a very crucial part of our planet’s biosphere.

Continue reading →

Wonderful Views of Life Using Micro-photography

The Olympus BioScapes 2011 Winners Gallery is full of great photos and videos of micro bioscapes.

Floschularia Ringerns Rotifer feeding by Charles Crebs

Winning photo by Mr. Charles Krebs, Issaquah, Washington, USA
Specimen: Rotifer Floscularia ringens feeding. Its rapidly beating cilia (hair-like structures) bring water containing food to the rotifer
Technique: Differential interference contrast microscopy

The photo shows the microscopic animal’s self-made reddish tube-shaped home, with a building block in the process of being formed inside the rotifer’s body.

An Apple a Day is Good Advice

Apples really are healthy food. They provide fiber and nutrients without a large amount of calories. Including them in your diet can contribute to a healthy lifestyle.

How apples can make you skinnier & 4 more health benefits of apples

Packing in quite a bit of soluble fiber (4 grams per medium apple) for a modest amount of calories (95) makes apples a filling, sweet snack. Plus, a medium apple counts as 1 cup of fruit, so after eating one you’re well on your way to meeting your daily fruit quota (around 2 cups for adults on a 2,000-calorie diet). They also are a good source of immune-boosting vitamin C (providing 14% of the Daily Value).
…
a survey of eating and health habits, found that people who had eaten apples in any form over the past day were 27 percent less likely to have symptoms of metabolic syndrome than those who didn’t. The apple eaters also had lower levels of C-reactive protein, a marker of inflammation whose presence in the blood suggests an increased risk for heart disease and diabetes.

“Our study suggests that ursolic acid increases skeletal muscle and brown fat leading to increased calorie burning, which in turn protects against diet-induced obesity, pre-diabetes and fatty liver disease,” Christopher Adams, M.D., Ph.D., UI associate professor of internal medicine at the University of Iowa.

Until quite recently, researchers believed that only infants had brown fat, which then disappeared during childhood. However, improved imaging techniques have shown that adults do retain a very small amount of the substance mostly in the neck and between the shoulder blades. Some studies have linked increased levels of brown fat with lower levels of obesity and healthier levels of blood sugar and blood lipid, leading to the suggestion that brown fat may be helpful in preventing obesity and diabetes.

Today, Most Deaths Caused by Lifetime of Action or Inaction

Chart of the Leading Causes of Death in 1900 and 2010

Our instincts lead us to fear the unknown and immediate threats (probably so we can be ready to run – or maybe fight). But today the biggest risks to an untimely dealt are not lions, other people out to get us, or even just random infection. We have to adapt to the new risks by taking action to eat healthfully and exercise, in the same way we we have evolved to avoid becoming a meal for a hungry beast.

Today the largest causes of death are heart disease and cancer (which account for more than 60% of the deaths causes by the top 10 leading causes of death). The next leading causes are non-infectious airways diseases, cerebrovascular diseases and accidents. Alzheimer’s, diabetes, nephropathies, pneumonia or influenza and suicide make of the rest of the top 10 leading causes.

In 1900 Pneumonia or influenza and tuberculosis took as many lives (per 100,000 people) and cancer and heart disease take today. We have done well decreasing the incidents of death (fewer deaths per 100,000) by greatly reducing and nearly eliminating some causes of death (the 2 leading causes from 1900 are good examples).

Continue reading →