Swapping out part after part

 kw: book reviews, nonfiction, medicine, prosthetics, transplanting

To start on a personal note: In these book reviews I typically relate the book's subject to my own experience. I started this blog when I was nearly sixty, and now, 21 years later, I'd say I have experienced a lot. In the light of the present book, however, I suppose I am fortunate that I have hardly anything personal to relate. Reading Replaceable You: Adventures in Human Anatomy by Mary Roach has been a fascinating adventure into realms unknown.

When I saw the title I wondered if the subject might be the various rates at which "we" are replaced, from daily for the lining of the stomach to never for the lens of the eye (unless we get cataracts removed and replaced with intra-ocular lenses–but that's a prosthesis). Perhaps you've heard that most of our substance is replaced every seven years. That's sorta so, and sorta not. But Ms Roach's subject is medical replacements, whether mechanical or transplanted. Plus an augmentation or two like breast and butt implants. 

This image was made using the Phoenix 1.0 engine in Leonardo AI.

The book starts with the nose. What do you do when it has been lopped off in a duel, as happened to Cyrano? A century or more ago, a strap-on or glue-on prosthesis of tin or leather was the best one could do. Later, various methods were developed of auto-transplantation (moving some "stuff" from elsewhere on your body to your nasal area). Get over your squeamishness if you want to read not just this chapter, but the book in general!

I must say, the author appears to have gotten entirely past any hints of squeamishness. She reports observing a variety of procedures in the operating room, including the careful disassembly of an organ donor, from whom the corneas are removed first, then almost everything but the head and bowels, even entire legs (stripped from inside the skin, which is repacked with filler materials for the funeral). A donor's parts can be enough to "edit" more than seventy other people.

Skin removed by catastrophic flensing or burning can't be attended to with any kind of prosthesis; the best solution is auto-transplants. It turns out that other kinds of skin can be used temporarily while your own body grows enough skin for repeated transplants. Frog skin isn't rejected too fast, plus it has antibacterial properties. If you don't mind being partly green for a few weeks!

Even intimate parts aren't exempt from needing repair, or reconstruction/construction. There are two ways to produce an artificial vagina for a trans woman. One is by turning the penis inside out, to be followed by a lifetime of "dilation" to keep this essentially permanent wound from sealing up. The other is by using other tissues of varying sensitivity to simulate vaginal mucosa, and sections of colon appear to work the best. And repairing (or constructing) male "equipment" can be equally cringe-inducing.

Are we still the sum of our parts, when more and more of those parts are "other"? In the chapter on xenotransplantation, using parts from pigs or other animals, the question is addressed: Is a genetically-modified pig heart OK to transplant into a Jew? With typically Talmudic wisdom, the consensus of the rabbis is, Yes, because the heart is not being eaten. At the moment, organs from pigs are a temporary measure, to stretch the life of a heart patient while waiting for a heart from a human donor.

We hope one day to be able to either grow an organ from someone's own stem cells, which becomes a homo-transplant. I have seen a few science fiction stories where rich persons (usually such persons are evil) have lab-grown bodies, self-clones, to be harvested as needed. If it can be thought of, someone will probably try to do it some day. A technology that is perhaps easier, and certainly can be faster, is to 3D print with special nozzles that spit out cells onto a framework, usually of collagen (which provides the structural framework of most organs). However, even a simple item like an earlobe has four or more cell types. It is like writing a multicolored letter using one of those special pens with four colors of ink you activate by pushing down one cartridge or the other. And for muscles in particular, the cells need to be in a certain orientation.

Thinking it over, I remembered that I have a few teeth with crowns. Dental crowns aren't mentioned in Replaceable, but they could have been. I wear glasses. I suppose those qualify as a supportive prosthetic. But other than that, I count myself lucky I've never needed to get a prosthetic hand, foot, leg, lung (Mary tried to sleep a night in an iron lung; she lasted two hours), or a transplanted finger, kidney or pancreas (a friend of mine was cured of diabetes...).

I've previously reviewed four of Mary Roach's books. She is becoming one of my favorite writers.