Tuesday, December 30, 2014

Turning New Year’s On Its Head

The New Year is nearly upon us. This time of year we think of birth, potential, new chances to accomplish goals. The fresh start is symbolized by the New Year’s baby entering as the old man of the past year exits stage right.

Say hello to the dancing baby, perhaps the world’s original viral
video and internet meme. If you remember when the baby first
showed up, you have seen at least 18 New Years and probably
watched Ally McBeal.
Well, I’m going a different direction. I’m interested today in discovering which living things have seen the most New Years babies. It should be easy, just survey all the species of living things on Earth, find the oldest member of each species, and declare a winner.

Unfortunately, it’s not so easy. Do you volunteer to track every naked mole rat to see which one lives the longest? How will we account for the hundreds of thousands, or even millions, of species we haven’t discovered as of yet? Maybe we will just have to use examples for those individuals and species we happen to have data for – that, and maybe some speculation.

A researcher in 1999 proposed a hypothesis that species body mass directly relates to longevity, ie. the bigger the animal, the longer it lives. There are myriad examples that don’t seem to follow his rule, and his hypothesis has met with substantial resistance, but the paper has been cited more than 1500 times so somebody’s buying it. More recent evidence from his group suggests that metabolic rate may be as telling as overall body size. It’s a live fast, die young hypothesis.

One of these images is of Misao Okawa, the oldest living human
as of late 2014. The other image is of Miley Cyrus and some of
her backup dancers. I don’t see Misao, so she must still be
working on her moves (Miley is the one in the middle).
As for humans, Misao Okawa of Okinawa will soon see her 117th New Year’s Day (as of late 2014). She is the oldest female as well as the oldest person, and attributes her longevity to consumption of sushi and a goal of becoming a back up dancer for Miley Cyrus. OK, I lied about one of those………sushi, who’d believe that.

Humans are amateurs when it comes to longevity. Jonathan, a Seychelles giant tortoise (Disochelys hololissa) is said to have seen 182 New Years. This is an estimate; a picture of Jonathan in 1882 shows him to be adult sized, and this takes about 50 years. So they guess he was born about 1832.

Bowhead whales (Balaena mysticetus) are second in size only to Blue whales, and individuals of this species are known to live for 210 years or more, making it the oldest living mammal species. Believe it or not, we can tell this by examining their ears after they die. They build a specific number of layers of ear wax each year, so we can just count the rings, exactly like with a tree – only yuckier.

A new study shows that bowhead whales have altered gene expression that may account for their longevity, especially in terms of fat metabolism and insulin signaling. The same study also shows that bowheads have parallel changes in gene expression that are seen in other species that live longer than one would expect – like the naked mole rat and Brandt’s bat.

The quahog clam isn’t really that big, so it defies the hypothesis
about size and longevity. The bottom image is a micrograph of
a quahog shell. You can count the layers to determine how
many growing seasons it has lived through, not necessarily
how many years. A new study examined the layers to estimate
ocean conditions over the last 400 years.
The ocean quahog clam (Arctica islandica) can live for over 400 years. A recent study indicates that this animal produces much lower levels of damaging molecules in their mitochondria (the energy generators of the cell). If we figure out how they do that we will be able keep our cells healthy for long times.

The oldest living individual organism THAT WE KNOW OF is a bristlecone pine tree in the White mountains of California. It's known to have seen at least 5064 Rose Bowl Parades. People can visit its grove to wish it a happy birthday, but you’ll have to guess which tree is the oldest – only one man knows and he isn’t telling.

In truth, the idea of what is old is not so easy to discern. As humans, we have a prejudiced notion of what “old” means. We are born, we live, we die. The person who remains vertical for the most days wins. But many organisms just don’t play by our rules. As a result, they can “live” for hundreds of thousands of years.

This isn’t the oldest Bristlecone Pine – or maybe it is. The Forest
Service won’t tell anyone which of the pines in this California
locale is actually the oldest. The unnamed tree is 5064 years
old, and shares its forest with another pine named Methuselah,
who clocks in at 4847 years old.
Organisms in harsh environments can just stop growing and go into suspended animation. Humans can only do that in science fiction movies like Interstellar. In the Antarctic, some lichens (a symbiosis of fungus and algae or photosynthetic bacteria) grow only 0.01-1 millimeter each year, and that’s in the good years. They can be in suspended animation for hundreds of years. Does that count as one life or two?

Samples of bacteria were “life suspended” until brought out in a Siberian ice core. Once thawed they began to divide. Are those bacteria several minutes old or 500,000 years old? They wouldn’t be growing and dividing except for the ice coring process. Maybe global warming will bring billions of old species back to life.

Let’s look at another way to circumvent the traditional idea of long life. Quaking Aspen trees (Populus tremuloides) live as colonies of clones. In the Pando clone of Utah, great stands of these trees cover more than 100 acres and constitute the heaviest single organism on Earth – over 6000 tons.

They all stem from one progenitor tree and they are all connected by one root system; roots sent out in a direction will turn upward and give rise to new trunks. Do we count the newest trunk to sprout and the first trunk that may have fallen over 80,000 to 1 million years ago as the same organism and the same life?

When injured, starved or bored, the immortal jellyfish will revert
from adult form to juvenile form and just grow up again. Can you
imagine an infinite number of adolescent periods? Imagine
the parents!
Maybe the weirdest example to demonstrate how hard to determine what constitutes a single life looks like is the immortal jellyfish (Turritopsis dohrnii). Take the name seriously. This small cnidarian lives in the waters of the Mediterranean Sea and off of Japan.

In typical jellyfish species, juvenile jellyfish live as polyps, then become bell-shaped medusae as adults – then die. However, the immortal jellyfish can revert from medusa to polyp and then grow up again. It can theoretically do this indefinitely, making the jellyfish ostensibly able to live forever. In practice, most die from disease or predation, but the possibility of infinite life is there.

One moral of our story – don’t worry about how many New Years Days you may or may not get to see – your number isn’t going to mean anything to anyone else. While studying old things may extend our lives in the future, be sure that you make of the most of the New Year you are being given now.

Contributed by Mark E. Lasbury, MS, MSEd, PhD

Munro D, Pichaud N, Paquin F, Kemeid V, & Blier PU (2013). Low hydrogen peroxide production in mitochondria of the long-lived Arctica islandica: underlying mechanisms for slow aging. Aging cell, 12 (4), 584-92 PMID: 23566066

Seim I, Ma S, Zhou X, Gerashchenko MV, Lee SG, Suydam R, George JC, Bickham JW, & Gladyshev VN (2014). The transcriptome of the bowhead whale Balaena mysticetus reveals adaptations of the longest-lived mammal. Aging, 6 (10), 879-99 PMID: 25411232

Holland, H., Schöne, B., Marali, S., & Jochum, K. (2014). History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium – A bivalve sclerochronological reconstruction Marine Pollution Bulletin, 87 (1-2), 104-116 DOI: 10.1016/j.marpolbul.2014.08.005

Tuesday, December 16, 2014

Giving, Getting, and Grey Matter

I give you the Griswold family Christmas tree. Did you see
Rusty there? That’s Leonard from The Big Bang Theory! He
also starred in the one other big budget 1989 Christmas
movie, Prancer. By the way, did you notice that in this
Griswold movie Rusty went from being Audrey’s older brother
to her younger brother.
The Jelly of the Month Club – the gift that keeps on giving. It’s that time of year again, time to feel the love or the loathe, battle the mall or e-tail ‘til you drop. Everyone likes to get gifts, but it seems our brains like giving them more.

Your kids make gifts for you just as you made gifts for your parents. Why, because kids don’t have any money (or maybe they do, more on that below).  You loved it when Ma or Pa unwrapped your macaroni necklace or the intricate drawing of the spaceman being eaten by the dragon.

The reason you thought your gift to them was so great can be explained by how your brain works. Dan Ariely, the behavioral economist, wrote about this is his book, The Upside of Irrationality. People value their own work more than they value other people’s work.

His example in the book had to do with building Lego toys – people would bid more to buy their own products than they would to buy the same products made by others. So the macaroni necklace from you was really a Tiffany original and your drawing put Renoir to shame.

And your parents loved your homemade gifts just as much as you love those from your kids. Why? Because your brain makes you….. er, allows you to. Receiving a gift activates the reward center of your brain. What's more, giving something away feels the same as when you receive something special, your brain doesn’t know the difference.

Research shows that giving a gift activates the same reward centers in the brain that light up when you receive a gift. Giving is a pleasure for the giver just as much as it is a pleasure for the receiver. This is why some Scrooges complain that people give to charity to make themselves feel good, not those they are helping.

If we covered the hands and present, could you tell who was
giving the gift and who was receiving it? Giving and getting
stimulate the same responses in the brain. However, women
are better at picking out gifts and men are better at
accepting gifts they don’t like.
Gift giving might even be more self-serving. In addition to the reward center activation, a 2006 study showed that gift giving activates the part of the brain involved in social connections and altruism. This part of the brain is activated when the gift is of greater benefit to the receiver than to the giver and is a true mark of giving in the best sense.

On the other hand, studies say getting a bad gift can actually harm a relationship. Men that received a gift from their significant other that did not match their known preferences or interests reported having less of a connection to the giver because of the choice. So the key is to pick out a gift that tells the receiver that you know them, you listen to them and you consider their perspective.

Popular theory has it that women are better at selecting gifts for other people than are men. That ain’t so at my house, but don’t tell my wife I said so. I think that women are better in general because they have more practice. They buy gifts all the time; little I’m thinking of you gifts, thank you for your gift gifts, thank you for your thank gift gifts.

That’s my hypothesis, but a scientific group in the Netherlands refused to take my word for it and did a series of experiments. They had men and women rank a series of possible gifts for people they knew and then had the potential recipient rank the gifts as well. Women did better at predicting the recipients’ preferences.

Another experiment in this study sought to determine why women were better. There results suggested that women were more connected with the meaning of the gift to the recipient. In short, women pick better gifts because they think more about the things they give.

Pearl is Mr. Crabs’ daughter and boy is she spoiled. Research
shows that giving kids too many gifts makes them unable to
discern needs from wants and puts pressure on them because
they know deep down that they don’t deserve them all. Now
explain to me why Mr. Crabs’ daughter is a whale!
So the quality of a gift can lead to stronger relationship and feelings of reward for both the giver and the receiver. But beware the power of gifts – you can have too much of a good thing.

Parents that overindulge their children through the giving of too many gifts can do harm. They don’t mean to, quite the opposite. They want to make their kids happy – it’s their job.

However, studies show that too many gifts cause insecurity and anxiety in kids. They can’t react strongly to too many gifts. So they pick one as a coping mechanism – and then they worry that they will offend the givers of the others.

In addition, giving your kids too much (material overindulgence) may lead to problems later in life with responsibility, delaying gratification, and in knowing what is normal.

Dr. David Bredehoft, the preeminent expert in the field warns that overindulgence leads to, “not knowing the difference between needs and wants; needing constant stimulation and entertainment from others; not taking responsibility for their own actions; overeating, overspending, and dysfunctional thinking (increased depressive thoughts). Paradoxically, overindulged children can develop an overblown sense of self-importance which can lead to problems at school, on the job, and/or in relationships.”

The problem continues as the overindulged become parents, “the more children are overindulged the more likely they are to become parents who: feel ineffective; believe they are not in control of their own life or their child’s behavior; think they are not responsible for their child’s actions, and that raising good children is due to fate, luck, or chance.”

This ad shows the brain at work. They tell you that you have to
add the eggs and that this creates “that homemade goodness.”
Do you think that change would be necessary today?
We can sum up gift giving for the kids through another lesson from behavioral economist Dan Ariely in The Upside of Irrationality. In the 1950’s, instant pie crust and instant cake mixes were introduced at the same time. They had pretty much the same ingredients, but the pie crust mix was a hit while they couldn’t give the cake mix away. It turned out that to make a pie, you had to add things to the crust, but the cake mix was the complete product in and of itself. Housewives had no pride in a cake they made from mix because they felt they hadn’t worked for it – they hadn’t earned it.

When manufacturers removed the powdered egg and oil from the cake mix, women started to buy it. They had to add something to create the cake. They took pride in serving it to their family or giving it away because they felt they earned it. It didn’t take much, but some work needed to be involved.

The moral - people value things they earn more than things they are given. The same is true for gift giving and receiving. If you have worked to make sure the gift you are giving is the product of your hard work, thought, and planning, you feel better about that gift. Likewise, if you have some sort of feeling that you deserve a gift and that it holds some meaning, then you will appreciate the gift more.

Too much given too easily lessens the specialness of the holiday season.

Contributed by Mark E. Lasbury, MS, MSEd, PhD

Pollmann, M., & van Beest, I. (2013). Women Are Better at Selecting Gifts than Men PLoS ONE, 8 (12) DOI: 10.1371/journal.pone.0081643

Dunn, E., Huntsinger, J., Lun, J., & Sinclair, S. (2008). The Gift of Similarity: How Good and Bad Gifts Influence Relationships Social Cognition, 26 (4), 469-481 DOI: 10.1521/soco.2008.26.4.469

Moll, J., Krueger, F., Zahn, R., Pardini, M., de Oliveira-Souza, R., & Grafman, J. (2006). Human fronto-mesolimbic networks guide decisions about charitable donation Proceedings of the National Academy of Sciences, 103 (42), 15623-15628 DOI: 10.1073/pnas.0604475103

Friday, December 12, 2014

The Friday Five

In this special edition of Friday Five, we’ve collected 5 of our best posts from 2014 that were inspired by the movies.

1. Jaws
Quick, Somebody Get The Name Of That Shark!

2. Planet of the Apes
Tough Talking Apes

3. The Incredible Hulk
Is It Really Possible For Someone To Turn Into THE HULK? Don’t Make Me Angry.

4. Star Wars
Midi-chlorians Gave Jedi Knights Their Power. Is There Something Like This On Earth?

5. Guardians of the Galaxy
I Am Groot! Plants Are More “Alive” Than We Think

Science quote of the week:

"Do or do not. There is no try” – Yoda, Star Wars: The Empire Strikes Back

Contributed by:  Bill Sullivan
Follow Bill on Twitter: @wjsullivan

Thursday, December 11, 2014

O Christmas Tree: It’s Not Easy Being Green

Evergreens are a remarkable mainstay in the evolution of plants. Evidence suggests that they have existed more or less in their present form for the past 300 million years. In other words, the evergreens are so resilient and exquisitely adapted to their environment that nature has not tweaked with their genetic recipe since the Permian. The evergreens can survive just about anything nature can throw at them, except humans. Nearly 40 million of these stoic conifers are chopped down each Christmas season in North America alone.

"Christmas Tree" farms cultivate a variety of evergreens that will grace one of 40 million homes each season. This makes it a lot easier than hiking into the forest to cut one down yourself.
Humans have long been fascinated by the evergreens because these trees and shrubs do not lose their leaves (needles) in autumn like the broadleaf trees. Seemingly in defiance to the harsh winter, the aptly named evergreens stay full and green all year long. Impressed with this act of endurance, early humans thought that evergreens must hold special powers. The ancient Pagans would place evergreen branches over their doors and windows to ward off evil spirits, especially during the winter solstice when the days were at their shortest and the nights at their coldest. Evergreens served as a reminder that the days would lengthen and the crops would grow once again in the spring.

A decorated evergreen is now synonymous with “Christmas Tree”, but this ritual has its “roots” in Paganism. Interestingly, it has even been argued that this passage from the Bible forbids emulating this Pagan practice.
So how do evergreens stay green year round? In winter, shorter days mean less sunlight. As sunlight is required for photosynthesis, plants face a dramatic reduction in energy during winter. To cope with this, broadleaf plants stop making chlorophyll, the molecule that drives photosynthesis and reflects green light. Consequently, the leaves change color and eventually fall off as the tree goes dormant.

By way of comparison, evergreen “leaves” do not have a lot of surface area; they are more resistant to lower temperatures and decreased moisture. Chlorophyll in these needle-like leaves is retained and photosynthesis can still generate energy from light, albeit at a much slower rate than spring or summer.

In addition to keeping chlorophyll, retaining moisture is equally important:  trees cannot extract water from frozen ground, and occasional sunlight in the winter can draw out precious moisture. Evergreen needles have a thick coating of wax and a slender shape, characteristics that help them hold water in and prevent evaporation, respectively.

A recent study has shown that the conifer’s ability to survive arid times involves the coordinated evolution of tissues regulating water supply (xylem) and water loss (stomatal pores) in the needle leaves. A plant hormone called abscisic acid helps keep the leaf’s pores sealed when water isn’t available. Another mechanism allows leaves to dehydrate and resist damage via a water transport system.

Close up image of pine needle – the small pores are stomata, which open and close to regulate gas exchange. When open, water vapor can escape.
Conifers have thousands of needle leaves, which help maximize energy production while not losing water to dehydration. Of course, evergreen needles do not last forever. They do need to be replaced, but conifers do this intermittently and a green appearance is always observed.

Ever since ancient times, the evergreens have been admired for their stamina and hardiness through the winter. They are a source of inspiration reminding us that better times are ahead. In this light, the ritual chopping down of the tree for decoration seems a most bizarre way to honor the mighty evergreen. Consider, instead, a Festivus Pole.

Contributed by:  Bill Sullivan
Follow Bill on Twitter.

Brodribb TJ, McAdam SA, Jordan GJ, & Martins SC (2014). Conifer species adapt to low-rainfall climates by following one of two divergent pathways. Proceedings of the National Academy of Sciences of the United States of America, 111 (40), 14489-93 PMID: 25246559

Tuesday, December 9, 2014

Winter Gives Me The Shakes

Ralphie’s mom was right when she bundled Randy up
for school in A Christmas Story. However, you can have
too much of a good thing. By the way, they never say
what the parents' names are in the books or the movie;
they’re just Mother Parker and the Old Man.
Last week we talked about ways the cold can kill you. Let’s be a bit more upbeat today and discuss that ways your body keeps the cold from killing you.

People tell you to wear layers of clothes when going out into the cold. Listen to them. Air is a great insulator as long it isn’t moved away from your body. Every shirt you put on traps another layer of air that can, once it’s been warmed by your body heat, keep you from losing heat to the environment.

But most animals don’t wear clothes, excepting those creepy organ grinder monkeys and the dogs and cats of little old ladies who own knitting needles and have too much time on their hands. Do animals (including humans) have a way to trap air without putting on layers of expensive and soon to be out of style clothes?

Yes - it’s called hair. Hair on its own will trap air and work to keep animals warmer in the cold, but Mother Nature has another trick up her sleeve. You have little muscles that attach the middle of your hair follicles to your dermal tissues. When these arrector pili muscles contract, they stand the hairs on end.

Standing hairs trap more air close to your body, so they do a better job at insulating you from the cold. Another, less attractive, result of this contraction is goosebumps. Yep, those little bumps are an evolutionary mechanism meant to keep you warm.

You say, “But I get goosebumps just as often when I am startled or creeped out as when I’m cold.”  I say, “Yes, you’re right.” And the reason is because of the way these muscles are innervated.

You (and everyone else) have two major nervous divisions to the peripheral nervous system (everything outside your brain and spinal cord); the somatic nervous system and the autonomic nervous system (ANS). The somatic system consists of sensory elements so you know what situation your body is in (temperature, pain, touch, etc.) and the motor nerves that let you make voluntary movements.

The ANS is involuntary. It’s rigged to automatically make adjustments in your activities to keep you on an even keel. Things like heart rate, pupil size, and thermoregulation are controlled by the autonomic system. One of the automatic adjustments for thermoregulation is the contraction of the arrector pili muscles. Think about it - you can’t make yourself have goosebumps.

We once had two cats – we named one Arrector and
the other Pili. Then we had more cats, and we named
them after beers because its tough to keep
coming up with clever names.
The ANS is also connected to your emotional state. Things like the fight or flight response aren’t under your voluntary control. So when you get the heebie jeebies, the ANS initiates responses for you to deal with it; your arrector pili muscles just come along for the ride. As a result, fear or eerie feelings may bring on goosebumps. Step on your cat’s tail and you’ll get a great demonstration of the arrector pili action independent of thermoregulation.

Recent research hints that arrector pili muscles may be involved in hair loss or maintenance as well. Degeneration of the arrector pili unit can lead to fatty infiltration of the hair follicle and a choking off of the hair growth. They don’t yet know just how this might happen so don't get too excited yet.

Since we humans don’t have much hair on our bodies anyway (Robe Lowe’s arm hair curtain character excepted) the arrector pili mechanism of thermoregulation doesn’t work so well for us. Good thing we have more tools in our toolbox. If you can’t insulate your body well enough to prevent heat loss, then you better conserve the heat you have.

Hairy Rob Lowe couldn’t freeze to death he tried.
He looks like he’s wearing a sweater even
when in the bathtub.

Thousands of chemical reactions occur in every cell of your body every second. Most of those reactions are not 100% efficient. Some of the energy transferred is lost as heat instead of going to do work.

We spend a great deal of energy and have to eat a great deal just to ensure that reactions produce heat and keep us relatively warm; as mammals we are homeotherms (misrepresented by the commonly used - warm blooded).

What can we do to make sure we lose less of this precious heat to the cold air around us? We can bring less heat to the surface of our body. A major amount of heat is carried in the blood, so if we keep our blood more centrally located in our body, then less of its heat will be lost to the environment.

We have muscles to do this as well. Constricting muscles are located in our blood vessels and control the size of the "pipes." Make the pipe smaller and less blood flows through it. Narrow just the pipes (vessels) near your skin and you lose less heat to the environment. The narrowing of the vessels is called vasoconstriction and is the reason your skin turns pale when you are cold.

This is a thermal image of two hands. See how the top
one shows cooler colors? This is what happens during
vasoconstriction of peripheral vessels and why fingers
are susceptible to frostbite. Why is it only one hand?
This is a diabetic patient and they can have a localized,
exaggerated response to cold with severe
vasoconstriction – it’s called Raynaud's phenomenon.
Vasoconstriction comes at a price. We discussed last week how constricting the surface vessels in your appendages (toes, fingers, nose, ear lobes) makes them more vulnerable to frostbite because there is less warm blood flowing through them. Evolution says its better to lose a toe to the cold than to lose all your heat to the environment and die from hypothermia.

OK, your arm and leg hairs have stood on end to trap air and you’re pale as a ghost due to vasoconstriction, but you’re still cold. We need to make more heat!

Like we said above, the workings in your cells are far from efficient. Muscle movements are especially good at generating extraneous heat. That’s why you sweat while you ride your stationary bike – you know - that thing with all the clothes hanging on it.

Shivering is a cold-induced set of micromuscular spasms intended to generate heat without forcing you to make big movements that might be counterproductive. It’s a pretty good way to regulate your temperature in the cold, and research shows that it is as good as exercise in burning excess calories.

The bad news is that babies, small children, and the elderly can’t shiver; they haven’t developed or have lost the muscle coordination to pull it off. Babies need a different way to generate heat. And wouldn’t you know, nature has given them one.

We all know about baby fat, the fat that’s so hard to lose and makes pubescent girls hate the world. Well, brown adipose tissue (or BAT, a better name than baby fat) is remarkable stuff. It's brown because these adipose cells contain more mitochondria (the energy factories of our cells) and mitochondria contain alot of iron.

Sometimes white adipose tissue helps you stay warm
too. It is best if you have an even layer of fat over your
entire body. Lynne Cox is such a person, and she can
do long distance swims in freezing water – like
swimming from a ship 2 miles to Antarctica.
Mitochondria use carbohydrates or fat to make chemical energy, and a bit is lost as heat. But what if you disconnected the making of chemical energy from the burning of carbohydrates and just let all of the energy be lost as heat? It’s called non-shivering thermogenesis; a pretty cool trick - pun intended.

A UCP-1 protein (uncoupling protein) in the mitochondrial membrane allows for energy (fat or glucose) to be burned without converting it to chemical energy. More mitochondria in BAT means that even more heat can be produced. Babies are smart!

And you can be smart too. You can teach yourself to make BAT even if you’re not a baby. Recent research shows that cold acclimation can induce BAT formation, and that the hormone melatonin can convert regular fat (WhiteAT) to BAT.  Other research shows that your autonomic system can also turn WAT into BAT if stimulated to do so.  

So if you want to build the easily lost BAT instead of hard to lose WAT – stay outside all winter. You will burn calories by shivering and lose weight by burning BAT. After the snows, you’ll be so hot!

Contributed by Mark E. Lasbury, MS, MSEd, PhD

Torkamani, N., Jones, L., Rufaut, N., & Sinclair, R. (2014). Beyond goosebumps: Does the arrector pili muscle have a role in hair loss? International Journal of Trichology, 6 (3) DOI: 10.4103/0974-7753.139077

Jiménez-Aranda, A., Fernández-Vázquez, G., Campos, D., Tassi, M., Velasco-Perez, L., Tan, D., Reiter, R., & Agil, A. (2013). Melatonin induces browning of inguinal white adipose tissue in Zucker diabetic fatty rats Journal of Pineal Research DOI: 10.1111/jpi.12089

Lim, S., Honek, J., Xue, Y., Seki, T., Cao, Z., Andersson, P., Yang, X., Hosaka, K., & Cao, Y. (2012). Cold-induced activation of brown adipose tissue and adipose angiogenesis in mice Nature Protocols, 7 (3), 606-615 DOI: 10.1038/nprot.2012.013

Bi, S., & Li, L. (2013). Browning of white adipose tissue: role of hypothalamic signaling Annals of the New York Academy of Sciences, 1302 (1), 30-34 DOI: 10.1111/nyas.12258

Tuesday, December 2, 2014

In Winter, Frozen Isn't Just A Disney Movie

Winter came early to a huge portion of the United States in 2014. Cold temperatures, slick roads and wind were the found in many places in mid-November. Heck, parts of Buffalo disappeared for more than a weekend.

Frozen is based on a Hans Christian Andersen tale called
The Snow Queen, written in 1844. In Andersen’s story,
there is an evil mirror that only reflects the bad in
something, none of the good. That’s like this post – we
talk about how winter cold can harm, not how it can
bring two sisters together and heal a broken kingdom.
It’s the cold temperatures that are the source of so much misery. A storm in the North Pacific changed the flow of the jet stream, and freezing temperatures dipped low into the US. People had to take measures to avoid freezing to death – literally.

Low temperatures can kill a person in a couple of ways. Frostbite is the freezing of parts of the body. Your cells are mostly water; when water freezes it forms crystals. The crystals are sharp and are larger than the same amount of water (ie. water expands when it freezes). This leads to punctures in the cell membranes; the affected parts of the body sort of digest themselves due to the release of enzymes from the broken cells.

Frostbite usually affects the extremities - toes, fingers, nose, ear lobes, private parts for men - because they have less blood flow and are harder to keep warm. Your body also sacrifices these body parts in an effort to keep warm by constricting blood vessels to keep the majority of blood from cooling and carrying the cold back to the center of the body.

Reduced blood flow is usually the reason for frostbite; less blood in the area means less heat, which means a greater risk for freezing. The reduction could come from physiologic vasoconstriction, or from underlying medical conditions that result in poor circulation. For instance, people with diabetes have poorer circulation and are much more susceptible to frostbite.

We add salt to the streets to lower the freezing temperature
of water. But on your skin, salt and ice lead to rapid frostbite.
The first person to try the salt and ice challenge could be
forgiven, but for anyone who has seen the videos of the
aftermath and still tried it – I have no sympathy for you.
Areas that undergo frostbite can sometimes be saved by the  infiltration of new blood vessels (angiogenesis) and the replacing of the dead cells. But if freezing of deeper tissues (muscles, tendons, bones) has occurred, this will probably not be possible. If larger/deeper areas are involved or if there is infection, amputation could be necessary. If no treatment is rendered – a person could actually die from the toxins released by an infection or from the dead tissue.

Interestingly, many sources of frostbite information state that if you are going out into the cold, you shouldn’t drink alcohol or smoke (tobacco or marijuana), as they can predispose you to frostbite. A 1997 study of blood flow in acute smoking showed that peripheral blood circulation was decreased from the moment smoking began. A 2008 study extended this to second hand smoke as well, showing that nicotine impairs microvascular function.

Marijuana gets a double hit, since it lowers blood pressure AND vasoconstricts the peripheral vessels. This is bad news for Colorado; legal pot and lots of cold weather. Likewise, drinking alcohol immediately before going out in the cold is dangerous because it is vasoconstrictive immediately after ingestion.

There’s a potential new problem in frostbite. With the
increase in solid organ transplants, it is becoming more
evident that some organs are being transported at too
low a temperature and they are being damaged. A recent
study examined frostbite in a liver to be transplanted
into an 18 month old.
On the other hand, the same cold temperatures that lead to frostbite can also kill you directly. Hypothermia is the bone-chilling cold you feel when your entire body’s temperature is dropping. Your normal body temperature is 98.6 ˚F (37 ˚C) or thereabouts. At 95 ˚F (35 ˚C) hypothermia begins. At 91 ˚F (32.7 ˚C) you get amnesia, and below 85 ˚F (29.5 ˚C) you lose consciousness. Now you’re in trouble.

Hypothermia can kill you in several ways, two of which have to do with electricity. Your heart beats because it supplies itself with a chemico-electrical jolt every second or so. This is what occurs in the sinus and AV nodes of the heart and is based on an electrical charge difference across the cells' membranes in the node.

Low body temperature messes with the membrane potential, so the heartbeat is slow and erratic. Too slow (bradycardia) or too erratic (arrhythmia) leads to a heartbeat so dysfunctional that it won’t push the blood through your body and you die from cardiac failure.

Electrical messaging is also how your central and peripheral nervous systems work. Not only does cold temperature slow the nerve impulse by altering the membrane potential, but it also slows the transfer of the signal from one neuron to the next. The neural synapse is the gap between two or more neurons and relies on chemical messages (neurotransmitters) released from the upstream neuron to trigger and electrical signal in the downstream neurons.

Cold temperature slows the release and/or reuptake of the chemicals in the synapse, so brain function is altered. This explains the confusion many people experience in hypothermia and the “paradoxical undressing” that victims often carry out.

That’s right, people who are so cold as to affect their brain activity often strip right there in the cold. It seems that as the small muscles that control vasoconstriction in an effort to prevent hypothermia will finally fail after working for a long time.

In some cases, lowering the body’s temperature radically is
beneficial. Originally called therapeutic hypothermia, the
technique is now more controlled and is called target
temperature management, as reviewed in this late 2014
publication. Lowering the body’s temperature for a short time
is effective in preventing some of the damage done by
cardiac arrest or stroke.
This creates a short vasodilation that brings a burst of relative warm blood to the skin. The victim may feel a hot flash, and in his/her altered neurologic state might take their clothes off to cool down. I saw no fewer than 16 cases based on just a cursory literature search.

Finally,  our proteins have evolved to function best when they are held at 98.6 ˚F. One could ask, did the protein conformation (its folded shape) evolve because of our temperature, or did our temperature evolve because our proteins fold a certain way? In either case, every protein’s function is based on its conformation, and the folding and shape are dependent somewhat on temperature.

Lower your body’s temperature and the proteins’ shapes will change. When this happens they don’t work so well, and this throws off your entire physiology and metabolism. Throw it off too far, and there’s no coming back.

Next time we talk together - what can a person do to avoid frostbite and hypothermic death? Stay out of the cold by moving to Florida or buy every warm piece of clothing North Face offers. These are ways humans overcome the environment, but there are also physiologic ways our bodies can combat the cold.

contributed by
Mark E. Lasbury, MS, MSEd, PhD
As Many Exceptions As Rules

Palmers PJ, Hiltrop N, Ameloot K, Timmermans P, Ferdinande B, Sinnaeve P, Nieuwendijk R, & Malbrain ML (2014). From therapeutic hypothermia towards targeted temperature management: a decade of evolution. Anaesthesiology intensive therapy PMID: 25421924
Argacha, J., Adamopoulos, D., Gujic, M., Fontaine, D., Amyai, N., Berkenboom, G., & van de Borne, P. (2008). Acute Effects of Passive Smoking on Peripheral Vascular Function Hypertension, 51 (6), 1506-1511 DOI: 10.1161/HYPERTENSIONAHA.107.104059
Adams MD, Earnhardt JT, Dewey WL, & Harris LS (1976). Vasoconstrictor actions of delta8- and delta9-tetrahydrocannabinol in the rat. The Journal of pharmacology and experimental therapeutics, 196 (3), 649-56 PMID: 4606
Morioka C, Kondo H, Akashi K, Matsumura K, Ochi N, Makinaga G, & Furukawa T (1997). The continuous and simultaneous blood flow velocity measurement of four cerebral vessels and a peripheral vessel during cigarette smoking. Psychopharmacology, 131 (3), 220-9 PMID: 9203232