Headless frogs generated in lab. Speculation on generating headless humans. Such headlines did not appear when Scharf and Gerhart (1980) presented the results of their experiments on the ultraviolet irradiation of embryos of the clawed frog, Xenopus laevis. Repeating earlier work, they irradiated the single-celled embryos, which resulted in abnormal development along the head-tail axis and in headless tadpoles. They then added to the earlier studies by showing that simply tilting another batch of irradiated embryos would correct the defect and generate normal tadpoles. Four years later, in a second-year undergraduate lab in Toronto, about twenty students repeated the Scharf-Gerhart experiments as a part of their education in developmental biology. In either case, there was media silence about their experiments, which also resulted in deformed tadpoles.

Not so, recently. In October 1997, Jonathan Slack of the University of Bath announced the results of his recent work on Xenopus development. (See also Pownall et al., 1996) By altering the expression patterns of fibroblast growth factor, Slack was able to perturb the normal head-tail development of the resulting tadpoles in order to produce tadpoles that appeared remarkably like those in the Scharf-Gerhart experiments. The announcement of these findings promptly led to speculation on possible applications in human development, and in the possibilities of generating human organs for transplantation. Unfortunately, someone missed the part where Slack opined that using this technology to generate anything resembling a human embryo was out of the question.

Almost immediately, the headlines screamed about headless human clones being generated for organ harvesting, and all hell broke loose. The quacks and crackpots crawled out of the woodwork to announce that the end was nigh, or that we were ready for the next step in human evolution. In either case, the zealots did little but scare the nonscientific community, and I was asked by innumerable friends if I thought that this was possible. Possible? Yes. Probable? No.

First let's consider the problem of cloning, without which we will still be faced with the problems of organ rejection. The only way around this is for each of us to maintain a clone of ourselves, a la the cloned sheep Dolly 'n' Polly, and this will be neither easy nor cheap. For one thing, where are we going to keep all of these "corpsicles," to borrow an expression from Larry Niven's Integral Trees. I know a number of couples with children and the one thing that gives them the greatest headache is trying to find decent and affordable day care, and this is for fully cephalic children who are relatively autonomous. Can you imagine some poor day-care worker trying to come up with games and amusements to exercise the headless? Right away you have to exclude television, and if it weren't for television, most parents that I know wouldn't know what to do.

Then you have to think about the whole cloning phenomenon. So far, the headless phenotype has worked only for frogs in the embryonic state; and in the Scharf-Gerhart experiments, none made it to metamorphosis, making this phenomenon uninheritable. Admittedly, breeding would not be the goal for the establishment of a line of clones, but then how effective will it be when you get angry at someone and tell them, "Go clone yourself!" Further add the fact that even in corpsicles, you can expect some organ degeneration with age, so that you'll need to start another batch every few years. This means that it will be affordable by about four people, and they already tend to be at the top of present organ recipient lists. The only thing that will grow exponentially with the cloning and manufacture of headless humans is the number of lawyers arguing about corpsicle rights.

There just isn't a need for organ harvest through this manner when there are cheaper and less controversial options open to us.

Did You Know Xeno?

Another area of intense research for organ donation is that of xenotransplantation. This involves the transplantation of an organ, tissue, or cells from animals into human hosts. One of the most famous examples was the placement of a baboon's heart into an infant, which sent shock waves through the scientific and lay communities several years ago. More recently, there has been an endless discussion on this field of dreams (see the September 1997 issue of Nature Medicine; free registration required to view abstracts).

There have been a number of animal systems touted to best serve human purposes, but one that stands out is that of pigs. What this says of humans is best left to the imagination. While ape and simian species are more closely related to humans, this actually backfires for xenotransplantation in that they are also more likely to host pathogens dangerous to humans. For some reason pigs are better suited to our systems, furthering the idea that all animals are created equal but that some are more equal than others. This also supports the premise, espoused by some, that men are pigs. Recently, pig donors suffered a setback when two British research groups found porcine retroviruses that appear to be transmissible to human cells (Le Tissier et al., 1997). But this has led to some hope in the biotech industry that a massive breeding program will be needed to genetically weed these viruses from the pigs, greatly increasing the long-range profit margins of resulting tissues.

But there's a bigger issue at stake here. How will xenotransplant patients be treated by the lay and scientific communities? What kind of ridicule can they expect to face? Will the powers of political correctness come to their aid? Will phrases like pig-headed, he's a mule, and he's a bear in the morning be stricken from common usage? What will we do when people really are pigeon-toed, have crow's feet, and have a frog in their throat? Will xenotransplantation lead to xenophobia? These questions must be answered before we should proceed with this line of research.

It's Not Easy Being Green

For those who like to remember the good old days, you can still get your organs the way Grandma used to get them. The problem is that there are too few deaths to fill the need. People just aren't dying quickly enough, and too few have organ donor cards. The majority of the world's dying are doing so under conditions detrimental to the production of good, healthy organs for transplant, and are often geographically removed from those in need. Talk about selfish.

Of course, there are those inventive few who have found a way around this problem. Recent reports out of China say that medics have started to harvest organs from the bodies of deceased prisoners (Chelala, 1997). Needless to say, this practice would cause a few problems in much of the Western world, but we must not have closed minds. Consider it the ultimate in "reduce, reuse, and recycle." If a prisoner cannot be rehabilitated as an upstanding citizen of society, perhaps he should be relocated in an upstanding citizen of society. This would also help to assuage the problem of how to house the corpsicles, in that the prisons are already there. Tapping prisoners would go a long way toward cutting down on prison overcrowding. And think of the notoriety if you receive an organ from a really famous prisoner. Looking for advice on a present for someone who received Hannibal Lecter's liver? Might I suggest fava beans and a nice Chianti?

Oh, and while we're on the subject, can I interest anybody in some of this new food I'm marketing? I call it soylent green. It's everything a body could want.

UV-Rescue Experiment in Xenopus - background and protocol for an undergraduate lab that replicates the Scharf and Gerhart experiment. From Reed College's Biology 351 course.

Response to the Advisory Group on the Ethics of Xenotransplantation, made to the Department of Health - position paper of the Institute of Biology's, an association for British biologists. This document discusses several issues brought up in this HMS Beagle column, and suggests future actions.

Fact Sheet on Xenotransplantation - contains information from the U.S. FDA on proposed guidelines for xenotransplantation.

Xenotransplantation Archives - the series of xenotransplant-related experiments that occurred at the University of Pittsburgh Medical Center from 1993 to 1995. From the UPMC News Bureau archives.

Focus on Xenotransplantation - based on Nature Medicine's September 1997 issue; contains full text and graphics from several articles.

Won't You Donate? - lists several ways to get an organ donor card through the Web and by mail.