Timing is everything...

...in the life of the lymphocyte.
Originating in the bone marrow, a subset of lymphocytes migrates during gestation to the thymus gland. There they "learn" to identify antigens, both foreign and native. It is in childhood that these cells are most active, when they set their "memories". In later life they are then prepared for the daily onslaught of parasites, toxins, and foreign bodies that seek to harm us.

Research has shown that children who are "unexposed" to a broad array of antigens have difficulties later with immune disorders of all types. The thymus involutes by puberty, so this timing makes perfect sense. Parents who misguidedly "protect" their children from common antigens and vaccines are doing them no favors. Our immune systems have evolved to use childhood as the time during which we lay down a healthy and vigorous immune system--there is no data to suggest it can be "overwhelmed" except by real disease at this stage. The fact that we are seeing a generation of immune deficient, hypersensitive, and disordered young people is a direct result of our scientifically illiterate approach to our own bodies and those of our children.
In a very real sense, children who are allowed to get "dirty" are healthier than those who are kept "too clean." Recent studies document this as a direct cause of the increased incidence of allergic asthma specifically.
And children seem to know this....

It's DNA....

...that makes the world of life go 'round.
One of the greatest breakthroughs in medical science as been recombinant DNA technology. Among other things, it has allowed us to produce human insulin and various "biotech" medications and tests that have given us a great advantage in our study and treatment of chronic disease (it's been pretty useful in acute disease as well).
Products of recombinant DNA technology, in which desirable genes are inserted into the target genome via viral or bacterial transmission, are NOT "artificial". They are essentially hybrids. The history of life itself rests on hybridization. Genetic engineering started 10,000 years ago with the emergence of agriculture; that process is not more nor less "natural" than recombinant engineering. Sexual reproduction itself is recombinant DNA technology.
So don't let the scientifically illiterate scare you--look it up for yourself and make your own decisions. Genetic modification is by and large a positive adaptation!

Be thankful for it.

DNA.
Here we see it (by EM) "unlinked", simple yet so powerful. We are only beginning to learn its secrets. But what we know already reveals how perfect it is for what it does, and for what it needs to do to make sure life continues.
Science is about exploring the nature of our world, not about philosophizing about where it came from.
I, however, know in my mind and heart that we are fearfully and wonderfully made, and see DNA as further proof of that.
Have a great holiday--I will be seeing some of MY DNA in my new baby granddaughter, Aletheia, and other bits of it in the rest of my family. Beautiful!

Small but mighty...

...the pituitary, the master gland.
Nowhere is the incredibly delicate complexity of the human body more clearly seen than in the endocrine system, where the pituitary runs the show.
Enthroned in the sella turcica (which is NOT an Italian sports car), it connects all higher order functions, emotions, and sensory inputs to that otherwise immobile lump we call the body. Through its intricate feedback loops it controls every cell, every reaction, every movement--millions of them each second. Usually without a hitch.
So think kind thoughts about your pituitary today and it will continue to hum along,
proving once again that we are fearfully and wonderfully made.

Pros and eus....

...as in "karyotes"?
Prokaryotes are organisms without nuclei (kingdom Monera) and eukaryotes are with (the other four kingdoms).
What is truly remarkable, though, is that the genetic material of both, and of viruses, which are not (yet) considered a living kingdom, is DNA-based. Therefore, the likelihood that we are unrelated is virtually zero. Even more remarkable is that life, in the form of prokaryotes, probably came into existence not after 2 billion years but almost as soon as the Earth cooled enough to support it. Far from being an "accident", it seems that life was "programmed in" to the birth of the universe. This concept is explored in many books, but one of the best is
The Goldilocks Enigma, by Paul Davies.
Regardless of one's beliefs about origins, this "inevitability" of life means we are not a vanishingly small probability but a prime factor in the makeup of the universe.

Thanks also...

...to our porcine friends,
who have (or, had) heart!

Have a good weekend.

Talk to...er, learn from...the animals...

...in many ways.
Thanks for the
"donations",
guys!

Fungus among us....

One of the pathogens that we have been able to keep a bit ahead of, at least as compared to bacteria, are the fungi. In general human beings are not often harassed by members of this kingdom, unless we suffer from immune compromise. Then they are killers.
Amphibians and plants have not been so fortunate. The current world-wide die-off of frogs and related animals and the continuous battle we fight on behalf of our crops are a result of fungal invasions...relentless and intractable.
Part of the reason for fungal power is their role as a decomposer--they eat trash, literally. And if that trash is wet, all the better. They are also great at killing their microbial competitors--penicillin came from a fungus as have other antibacterial agents.
Some fungi are good--lovers of stinky cheese and mushrooms (like me) appreciate them in their proper place.
But watch out--fungi can turn on us in a New York minute if it is to their survival advantage.
Just ask the poor peepers.

In the beginning....

...there is the neuron.

In the beginning....

...there is the neuron.

Sulfuric Acid rocks!

Japanese rock group Sulfuric Acid; aren't they lovely?--->

Now that we have your attention, please turn it to acids and bases.
These useful compounds help organisms process things they need in a world that is composed of things that in their turn might require a little "assistance" with that processing. Sucking up protons, pushing in protons--acids and bases can make indigestible items like rocks and steaks and even potentially poisonous substances useful.
Living organisms are themselves buffers that resist the negative effects of acids and bases.
Be thankful for those proton pushers!

Love your neuroglial cells...

...because they love you!
The neurons get all the attention, but it's the neuroglial cells that really make us what we are neurologically. To paraphrase a Streisand song (Queen Bee), "The neurons got the muscle but the neuroglia's got the hustle."
Like the best insulator in the universe it is, neuroglia (when rapped around an axon or dendrite it is called "myelin") keeps the signal in the neuron pure and focused as it moves along carrying its message. And FAST! I love the kangaroo analogy, but in reality it should be a cheetah.
One only has to see the effect of damaged neuroglia to realize how critical it is. Most neurodegenerative diseases are of the neuroglia, and it is the disruption of signaling effectiveness and efficiency that leads to the distressing signs and symptoms of multiple sclerosis, Alzheimer's disease, cerebral palsy, and other conditions. Due to its ability to reproduce (as opposed to the non-mitotic neurons) neuroglia is unfortunately the source of most neurologic malignancies.
On the positive side, it now appears that the metabolically very active neuroglium is responsible for much of acquired intelligence and all learning, since as it grows and reproduces it allows the more static neurons to establish better and more creative connections. It needs plenty of oxygen and lots of carbs, so exercise, eat your pasta, and ditch the cigarette butts in the cause of SCIENTIFIC LITERACY and GENERAL INTELLIGENCE!
Neuroglia rocks!

We love buffering!

Acids "donate" protons, bases accept them.
Sounds simple. Runs hard.
The process of donating a proton, or a positively charged hydrogen ion, can cause significant chemical changes in the metabolic environment, destabilizing proteins, lipids, and carbohydrates and disrupting cellular processes, including energy production, protein synthesis, and reproduction. The more forcefully the acid foists the unwelcome proton upon surrounding organic molecules the more deleterious the result. One only has to realize that our stomach acid (hydrochloric, pH 2) can "melt" a tough steak to understand
why acids are so harmful to our tissues.
It is noteworthy that our body's normal extracellular environment is not actually neutral (pH 7) but slightly basic (7.35 - 7.45). My students hypothesize that the "reason" for this is that the environment in which we evolved and live has more acids of potential harm, and so endowed the body with a slight "head start" in the buffering process.
Excellent thinking!
Negatively charged bases, which "suck up" protons, can also cause serious cellular damage;
they are just not as common in our environment. Lye, a severe caustic, is strongly basic and can "melt" tissue as easily as sulfuric acid.
The body has evolved complex and delicately balanced systems to keep us from becoming too acidic or basic, either of which can lead to serious ahomeostasis or death;
this is another aspect of our being fearfully and wonderfully made!
Be grateful for your buffers!

The race....

An important element of modern evolutionary theory is the principle known as The Red Queen (discussed elsewhere on this site). Organisms' immune systems, including those of humans, must constantly evolve in order to keep up with, or hopefully ahead of, pathogens. (The Red Queen in Wonderland had to run just to stay in the same place.) This is perhaps why, despite its theoretical promise, immunotherapy has had limited success, especially in cancer. The environment in which the immune system operates is simply too volatile, and its priority needs to be the acute assaults of infection rather than the chronic siege of cancer.
Gene therapy has likewise been a disappointment, for different reasons. The theoretical value of replacing "faulty genes" with "good" ones is still clear, but in practice the obstacles have been tremendous. Our genes have developed to resist changes that do not bestow reproductive advantage, and overcoming that resistance has proven fearsomely complex.
Despite our grandiose beliefs to the contrary, the natural form of evolutionary change has done us quite well, thank you, since long before we put on white coats and looked in a microscope, and I expect it will continue to do so. We tamper with it at our own peril.

Learning by...osmosis?

Osmosis is actually the movement of a solvent, such as water, through a semipermeable membrane (SPM) from an area of LOW solute concentration to an area of HIGHER concentration; the resulting concentrations are equal, but midway between the HIGHER and the LOWER. "Learning by osmosis" would actually result in LOWER or diluted content knowledge, assuming that the solute represents the information.
The actual metaphor should be DIFFUSION, in which the solute moves across the famous SPM from an area of HIGHER concentration to LOWER. The resulting concentrations are equal but the direction of movement is toward the "emptier" solution. Like a brain?
However, neither analogy is correct regarding the learning process. The actual metaphor is closer to FACILITATED DIFFUSION, in which the material moves down the concentration gradient using an enzyme or cell receptor and consuming energy, or ACTIVE TRANSPORT, in which a carrier protein moves the information consuming even more energy.
Either way, learning is not passive and requires energy!

Cancer....

The word is fearful, as it should be.
Somehow, our bodies' exquisitely balanced defenses break down with time or repeated assault and what has been a blessing, responsible for growth and healing and reproduction, becomes literally malignant.
Unscrupulous quacks will try to get victims to believe that cancer can be cured with the Banana Fiber Diet, or the Salt Water Cure; the only defense against such vicious cruelty, which is all it can be called, is knowledge of the underlying pathophysiologic mechanisms and how to read scientific literature. Know your body!
Become scientifically literate--it could save your life or that of someone you love.

Carbon-based life....

In college it was known simply as "O chem"--for pre-med students, the most feared and despised class of them all--organic chemistry, the chemistry of life. If you didn't get an A in this class, med school was simply not in your future. Some people took it twice, thrice--only to be defeated by its fearsome complexity.

In retrospect it's not clear to me what the issue was with this subject matter. At the time we had no "peripheral brains" and had to memorize the structures of all those alcohols, aldehydes, and carbon rings. Now we can look them up. I think it was simply a test of determination, will, and memory...a method with which to "weed out" those whom the lords of medicine thought were not of the right stuff. Like any such test, the material itself was secondary to the process by which one learned it. And tested on it--those tests were strewn with the bodies and souls of would-be doctors across the land. Waterloo was but a trifle compared to the O chem final.
Now it makes so much sense to me--the material, not the use of O chem as a terrible winnower.
I hope my students feel the same....

If you have nothing else to do this weekend...

...why not spend it with meiosis?
This is certainly one of the most wonderful evolutionary adaptations sexually-reproducing species have developed. Not to mention one of the most confusing....
ALL biologists and clinicians MUST understand meiosis, because it is the basis for the wonderful genetic diversity that is both a blessing and perhaps a risk.
You guys have fun!

Water....

Water is the most critical substance to life, and contains the two most important elements.

How does ti doe its job? What does it really do besides make us wet?
Understanding water is a key to understanding physiology.
And to staying clean and juicy!

Physics first....

Physics is the study of matter and energy.

Historically, the sciences were studied "biology first", probably because biology is so "obvious". In addition, the "real" nature of the physical universe was not understood until the relationship between matter and energy was elucidated by Einstein and others in the early 20th century.
Over the past 20 years a movement within scientific pedagogy has developed that rightly teaches physics first. The nature of matter and its relationship with energy is the foundation of scientific understanding; that builds "up" into chemistry, which in turn allows biology to be understood as never before.
The basis for our studies in human biology is, in fact, physics.
Most people think physics is "hard"; it is, in fact, quite simple. Atoms, molecules, chemicals, cells, organisms--it's natural!

Cells even die....

gracefully.
Apoptosis, the process of programmed, orderly cell death, is essential to our bodies' structure and function. Were it not to happen in development, we would have webbed hands and feet, too many neurons, and a face from a horror movie. But, like it does everything, the body carries out this process effectively and efficiently, not even leaving any debris behind. In fact, should the body stop its orderly sculpting we may suffer from one of our most relentless enemies as a result--cancer.
Be grateful for death--it really is part of life.

Matter...

...not only comes in "regular" and "dark" but is actually convertible to and from energy, which also comes in "regular" and "dark". The famous equation, e = mc2, represents this essential singularity.
All energy and matter, therefore, are manifestations of the spectrum we call "light".
And God said, "Let there be light."