For more than two millenia, medicine has fought against death and
disease. It is only in recent years that some have questioned whether our
engagement for life and care was truly irreversible.
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The fundamentals of life
Life has a very, very long history, but for each of us it has a very
definite beginning: the moment of conception. Progeny and parents are united by
the threadlike molecule of DNA upon which the complete genetic information is
written in miniaturised language.
The spermhead carries one metre length of DNA, cut into 23 pieces, the
chromosomes, each of which is precisely coiled and visible under the
microscope.
As soon as one sperm penetrates the "zona pellucida" in which the ovum
is wrapped, it becomes impenetrable to other sperm. In purely operational
terms, as soon as the sperm's 23 paternal chromosomes enter the ovum, with its
23 maternal chromosomes, the total information necessary and sufficient to
dictate the genetic make-up of the new human being is established: not a
theoretical or a potential human being, but the very human being we will later
call Peter, or Paul, or Magdalene.
Just as the introduction of a mini-cassette into a tape recorder will
allow the playing of a symphony, so the music of life is played by the
machinery of the cytoplasm, and the new human being begins to express itself as
soon as he or she has been conceived.
Soul and body or spirit and matter are intricately interwoven at the
beginning of life. Indeed we use the same word, conception, to describe the
process by which an idea, a concept, comes to our mind as we do to define the
genetic process by which a new being, a conceptus, comes to life.
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Technicalities of early life
Once a month a ripe ovum is expelled from the ovary and enters the
uterine tube where it may encounter the sperm which, among thousands of others,
will fertilise it.
It is because natural fecundation occurs between a free-floating egg
and a free-floating sperm that In Vitro Fertilisation is possible in a glass
tube which replaces the uterine tube. At the cellular level the process is
identical.
Because sexually transmitted diseases and other pathological
conditions may occlude the uterine tube, it was proposed to bypass the
obstructed tube. If the ripe ovum is carefully aspired through a fine plastic
tube into a test tube to which sperm is subsequently added, fecundation can
occur. Two or three days later the tiny embryo, already feverishly organising
itself inside the walls of its private home (the zona pellucida), is
transferred to its mother's womb.
When Drs Edwards and Steptoe took the risk of replacing the tiny
Louise Brown into the womb of her mother, it was because everything in the
sciences of genetics and embryology assured them that this little berry-looking
being was neither a tumour nor a parasite, but a young member of our species,
the child of Mr and Mrs Brown.
With many children already born from this technique, it is an
established experimental fact that the life of each human being begins at
conception. Protected in its life capsule (the zona pellucida and then the
amniotic sac) the early human being is just as viable and autonomous as a
cosmonauton the moon: refuelling with vital fluids as required from the mother
vessel. At this stage shelter and nurture by the mother organism are absolutely
essential.
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Suspended animation
In Latin languages we use the same word for that which we measure with
a clock and that which we check with a thermometer (le temps). This is
appropriate because temperature is a measure of the agitation of molecules, and
this random movement defines the passing of time.
Refrigeration reduces the molecular motion so that close to absolute
zero "time comes to a standstill" as all movement stops. Because of their
extraordinary vitality, human sperm and even early human embryos can withstand
deep freezing and can be kept, so to speak, in suspended animation. Hence we
have sperm banks, familiar in animal husbandry, and some researchers even want
to set up banks of human embryos. Deep-frozen human beings may thus be thawed
and transferred into their mother's wombs or into rented wombs of carrier
mothers. Such embryo banks of warranted quality may be established with
carefully controlled and classified pedigrees. Although the majority of
scientists today deny any such intentions this possibility must be considered
when society assesses the future of such techniques.
At the present time surrogate mothers are very much "à la mode"-and
the biological mother may sell her child to the male buyer, usually with the
proviso that it must be normal.
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Respect for human nature
The expression "human nature" is not much in vogue these days among
some scientists. Nevertheless, human nature does exist: one only has to look at
human chromosomes to recognise their number, their size and even their specific
banding patterns. The student who cannot identify microscopically the
chromosomes of a chimpanzee, gorilla and a man would fail his exam! Human
nature is absolutely unmistakeable when it comes to reproduction. The most
advanced chimpanzee does not relate the act of copulation to the outcome of a
baby chimpanzee some nine months later!
Man is the only creature who knows that love and procreation are
united by nature. Even the pagans represented the god of love as a child. This
discovery comes from the dawn of human memory, the lost paradise.
The Warnock Committee recognised the special nature of the human
embryo when in their report they declared: "The status of the embryo is a
matter of fundamental principle which should be enshrined in legislation."
(page 63: para 11.17).
They also recognised that the process of human development begins at
conception when they stated: "while, as we have seen, the timing of the
different stages of development is critical, once the process has begun, there
is no particular part of the development process that is more important than
another; all are part of a continuous process, and unless each stage takes
place normally, at the correct time, and in the correct sequence, further
development will cease. Thus biologically there is no one single identifiable
stage in the development of the embryo beyond which the in vitro embryo should
not be kept alive..."
Thus, when referring to this statement, the Australian Senate Select
Committee on the Human Embryo Experimentation Bill 1985, concluded: "In this
situation prudence dictates that, until the contrary is demonstrated 'beyond
reasonable doubt' (to use an expression well known in our community), the
embryo of the human species should be regarded as if it were a human subject
for the purpose of biomedical ethics (Human Embryo Experimentation in
Australia: page 28; para 3.18).
Thus if we were to take the Warnock reference to early human nature
seriously, we must recognise that the embryo is not a perishable commodity to
be frozen and defrosted on demand nor a consumable product to be purchased or
transferred at will, nor experimental material, nor an item to be stocked for
spare parts. From conception, the embryo is an individual human being who
should be protected against exploitation.
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Future of medicine
Is repect for human nature an impediment to research? No.
To appreciate the truth of that answer let us examine the recent
progress made in the investigation and treatment of congenital and genetic
disease. Human embryo experimentation up to the fourteenth day of life as
recommended by the Warnock Report is not a necessary requirement for effective
medical intervention in these conditions.
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Congenital and genetic disease
Two years ago I was invited to address members of both Houses of
Parliament at Westminster. I explained that human embryo research as
recommended by the Warnock Committee could not produce any positive results in
the investigation and treatment of congenital and genetic diseases because at
fourteen days the organs and systems affected by these conditions have not yet
developed. In addition I suggested that effective research would depend on
techniques not requiring the use of human embryos. These comments were attacked
from all sides and Nature Magazine reported my comments as a "French influence
in Britain" (1).
Subsequently, Nature made an"appeal to embryologists"(2) in which a
prize of one year's free subscription to the magazine would be awarded to the
authors of the best submission showing what could be achieved by the use of the
embryonic human being. In this way, the magazine suggested, scientists would be
able to defeat attempts in Parliament to outlaw the use of the human embryo for
experiments.
To-day-two years later-Nature has still not published any relevant
papers. Such silence demonstrates the paucity of scientific argument justifying
human embryo experimentation.
Furthermore my prediction concerning effective research without the
use, of human embryos has been amply demonstrated by numerous investigators in
several countries. Vitamin supplementation before conception has been shown to
protect the embryo from neural tube defects in spina bifida. The new
developments in molecular biology applied to cells taken from adult patients
with cystic fibrosis (3), muscular dystrophy (4), Huntington's disease (5) and
retinoblastorna (6) have also generated a much greater understanding of the
genetic factors responsible for these diseases as well as their location within
the human genome. In addition there is now the possibility of treating and
curing certain genetic blood diseases with bone marrow transplantation (7).
None of these achievements has involved the use of human embryos.
In Down's syndrome-the disease in which I am particularly
concerned-there is an additional chromosome present in every cell of the
afflicted individual. This produces an "overdose" of genetic information and is
roughly comparable to a four-cylinder engine mounted by mistake with five
sparking plugs. The engine cannot run smoothly but the good motor-mechanic will
try to disconnect the extra plug ratherthan discard the engine. Although we
scientists do notyet know how to "unplug" an extra chromosome, nature does and
does it most efficiently. In the female each cell posseses two X chromosomes
whereas in the male each cell possesses only one X chromosome. Shortly after
conception one or other of the two X chromosomes in each cell of the female
embryo is inactivated or "unplugged" so as to prevent an overdose of the
genetic information on the X chromosome. This situation continues throughout
life. Through our research we hope to achieve a similar effect with the extra
chromosome 21 which is responsible for Down's syndrome.
Ourwork also involves deciphering the genetic content of chromosome
21. Five genes have already been identified on chromosome 21 and it is likely
that its full complement of genes will be determined during the next few years.
Last year we demonstrated that in Down's syndrome the cells are extra sensitive
to a drug which blocks the metabolism of monocarbons. These monocarbons are the
smallest "building blocks" used in the nervous system and perhaps their use can
be modified by drugs in children suffering from Down's syndrome.
I am not suggesting that the condition of these children will soon be
cured. What I do say, however, is that discoveries are being made and that
respect for human nature does not impair research but stimulates it. The
proponents of the use of the human embryo as a guinea pig were mistaken when
they put forward to the public this cruel suggestion: either you accept our
philosophy that embryos may be used or else you condemn families affected by
genetic diseases and you wash your hands of their sorrows.
Medicine is not forced to choose between paying Herod and Pontius
Pilate. There are possible lines of research in full accordance with medical
norms and already they are being demonstrated as fruitful.
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References
1. Walgate R. French influence in Britain. Nature 313, 21 Feb
1985.
2. Editorial, Nature, An appeal to embryologists. Nature 316,11.
3. Beaudet et al. Linkage of cystic fibrosis to two tightly linked DNA
markers: joint report of a collaborative study. J.Hum.Genet 39,
pp.681-693,1986.
4. Monaco, A.P., Neve, R.L. Colletti-Feener, c., Bertelson, CJ.,
Kurnit, D.N., Kunkel, L.M. Isolation of Candidate cDNAs for portions of the
duschenne muscular dystrophy gene. Lancet, 323, pp. 646-650,1986.
5. Landegent, J.E., Jansen in de wal, N., Fisser-Gren, Y.M., Bakker,
E. Van Der Ploeg, M., Pearson, P.L. Fine Mapping of the Huntington Disease
linked D4S10 locus by non-radioactive in situ hybridization. Hum. Genet. 73,
pp. 354-357,1986.
6. Friend, S.J., Bernards, R., Rogel, J.S., Weinberg, R.A., Rapaport,
J.N., Albert, D.M., Dryja, T.P. A Human DNA segment with properties of the gene
that predisposes to retinoblastoma and osteosarcoma. Nature, 323, pp. 643-646,
1986.
7. Hobbs, J.R.,Displacement bone-marrow transplantation and
immunoprophylaxis to treat some genetic diseases. Bone marrow transplantation,
1, pp. 333-335, 1986.
8. Lejeune, J., Rethore, M.O., de Blois, M.C., Maunoury-Burolla, C.,
Mir, M., Nicolle, L., Borowy, F., Borghi, E., Recan, D. Metabolisme des
monocarbones et trisomie 21; sensibilite aux methotrexate. Ann. Genet. 29,
pp.16-19, 1986.
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