Free Marrow by Elizabeth Lesser

science have always been a struggle for me. If I were a child now, I’d probably be diagnosed with a learning disability. It sure felt that way all through school. I had my first experience of math-induced brain freeze in elementary school when confronted with long division, and full-on mental paralysis in junior high when it came time to memorize the periodic table of the elements. But now I am motivated to fall in love with bone marrow and stem cells, so I stay up late every night, reading Essential Cell Biology .
    I discover that although bones seem as dead as rock, they are actually super alive. They are like living layers of geological sediment protecting a molten core. The core of the bones is the marrow, and in the marrow are the stem cells, the source of life. Stem cells are also called mother cells because they have the potential to create many types of new cells that your body needs in order to live.
    The human body is composed of one hundred trillion cells—give or take a billion—with each cell assigned a specialized function, like skin cells, blood cells, muscle cells, organ cells, brain cells. Specialized cells do not live very long, so the body needs toreplace them continuously. I used to think of my body as a constant—a trusty chariot that would cart me around till death do us part. But in actuality, my body today is not what it was yesterday or what it will be tomorrow. Humans shed and regrow skin cells every twenty-seven days, making almost a thousand new skins in a lifetime. Each day fifty billion cells throughout the body are replaced, resulting, basically, in a new chariot each year. Every second, 500,000 cells die and are replenished. Red blood cells live for 120 days; platelets live for only a week; white blood cells live for a mere eight hours.
    And then there are the stem cells that live deep within the bone marrow. Unlike specialized cells that die and must be replaced, stem cells are self-renewing—they divide in unlimited numbers and become new cells. Some of those new cells remain stem cells, and some leave the bone marrow and flow into the bloodstream, magically morphing themselves into whatever kind of specialized cells the body needs. A stem cell is like a mother. She sends her children out into the world to become who they were born to be.
    When doctors harvest bone marrow from a donor, it’s the stem cells—the mother cells—they are after. The premise is pretty simple: Destroy the bone marrow in the cancer patient and replace it with several million healthy stem cells from a donor. Then do everything possible to help those donor stem cells engraft in the cleaned-out cavities of the patient’s bones. If all proceeds according to the plan, the mother cells make themselves at home in the new bones and begin to self-renew, building a new bone marrow factory where baby blood cells are produced and sent into the bloodstream, bringing the patient back to life.
    Sounds like a good plan, but it’s also a dangerous one, becausein preparing the patient for the transplant with high-dose chemotherapy and radiation, healthy cells are collateral damage. The patient must endure a near-death experience in order to live. Sitting in the dark quiet of my house, underlining sentences in Essential Cell Biology , I can almost feel the river of life and death, change and rebirth, flowing in my bloodstream. I shut the book and close my eyes and say a quick hello and thank-you to my stem cells just in case we’ll be calling on millions of them soon.
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    field notes • march 20
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    i have always said i want to come back in my next life as an eggplant. a big stupid purple lump languishing in the sun, oblivious to the complex messes us humans make. until i met denise. now, i am considering withdrawing the eggplant request and asking for reassignment; i might want to come back as a human again. i had another round of pre-transplant radiation at the hospital today. on