The chemical symbol for the metallic element gold is Au, taken from the Latin word aurum meaning 'shining dawn'. In the Periodic Table of Elements it occupies a companionable neighborhood of other metals, tucked neatly between platinum (Pt) and mercury (Hg).
But as origin of its chemical symbol indicates, we've long found difficult to be prosaic about an element that possesses such a sunlit beauty. People have been creating ornaments of gold for more than 5,000 years; whole myths have been created about it, such as the ancient Greek tale of King Midas, who loved gold so much that he persuaded the gods to give him the power to turn what he touched to gold - eventually destroying everything he loved, including his daughter.
Gold was, in fact, thought to contain a sun-like power. The alchemists, in addition to trying to create gold from other metals, thought it might be used to make an "elixir of life". Even the influential 16th century chemist-physician Paracelsus experimented with this, seeking to create Aurum Potabile or drinkable gold.
In yesterday's post I told the story of a famed victim of such a gold elixir, also of the 16th century, Diane de Portiers, mistress of French king Henri II, whom historians now believed slowly poisoned herself with a gold-laced potion for youth.
Scientists studying her death noted that she exhibited classic symptoms of gold poisoning - famously pale skin, for instance. Saved and treasured locks of her hair were cocoon-silk thin. And her excavated bones were unnaturally brittle.
But how, you might wonder, did they even know that these were symptoms of gold poisoning? The answer it turns out is that we do see gold poisoning today, primarily as a side effect of the several uses of gold in modern medicine.
Although most of the gold mined today goes into jewelry production - an estimated 78 percent - the metal has proved useful in many other industries, including electronics including computers (gold is a wonderfully efficient conductor of energy), in dentistry, and, as I mentioned, in medicine.
For such uses, we are mostly talking about colloidal gold, a term used to refer to tiny particles of gold suspended in a fluid. These particles are so tiny that some people like to call them nanogold. The most common medical use of gold is in treatment of arthritis, especially rheumatoid juvenile arthritis, and the use of radioactive gold in some cancer therapy.
Why would gold be used in treating arthritis? Because it appears to suppress the autoimmune response and the painful inflammation of that disease. In other words, gold is immuno-suppressive. The metal has an affinity for T-helper cells, white blood cells that help boost the immune response. It slows down their production - and in doing so calms an overaggressive immune reaction.
Some studies estimate that about 50 percent of arthritis sufferers on gold therapy - injections of a colloidal solution - report relief. But they also run a legitimate risk of gold poisoning.
About one-third of people on gold therapy suffer side-effects. Most are more unpleasant than serious. But definitely unpleasant: nausea, dizziness, skin rashes, a metallic taste in the mouth and also sores in the mouth, and the thinning of hair seen in Diane de Portiers.
But like all metallic elements gold bioaccumulates in living tissue, building up in the body. And if it reaches high enough levels - de Portiers' had 500 times the normal level - then it is genuinely dangerous. It can destroy bone marrow, damage kidney, liver, and even lungs. The threat to bone marrow is high enough that most doctors recommend regular blood tests for people on gold therapy.
Just another remind that those so-called Elixirs of Life - even ones named after metals shining like the dawn - are ever really perfect.
Gold "microbeads" can be fired like buckshot into cells and biological tissues with DNA on them as a way to insert genes. It used to be a common alternative to viruses, but I don't know now. "Biolistics" was the company with the patent, I think.