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Non-animal
methods
Non-animal
methods are used wherever they can
provide the required information.
Many people have heard about research
using cell cultures and computers.
Some people may therefore assume
that, if a pharmaceutical company
uses animals, it must not be using
those methods. In fact, all research-based
pharmaceutical companies use those
methods.
Seeing emails go round the world
in minutes and broadcasting satellites
put in space with ease, it may be
tempting to think we ought to be
able to put a molecular formula
into a computer and come out with
a full print-out of what that medicine
will do in the human body. Understanding
the effects of a medicine in the
body may seem a small thing compared
to global communications networks.
In fact, no other man-made system
or natural phenomenon comes anywhere
near to the complexity of the body.
Computer
Research
Of course, we know a lot more than we used to and medical
technologies have made a huge contribution to limiting the
need for animals in some areas of research. The early part
of the pharmaceutical research process, where potentially
useful compounds are identified, used to need many animals.
This 'discovery' research now needs very few, thanks to developments
like high
throughput screening, huge robotic screening systems
that can check thousands of molecules in a day for any that
have a particular characteristic that scientists believe will
be helpful in treating a particular disease.
Computers can also design compounds where the necessary molecular
structure is known. For instance, researchers may know what
shape a molecule must be to block a receptor on a cell, effectively
'locking it' against the unwanted substance that is causing
the problem. They can programme this structural information
into a computer and get many thousands of possibilities very
quickly. These can then be screened in
vitro for other useful or harmful effects.
In
vitro (in glass) research
New advances have made it possible
to keep tissue alive and in good
condition and cells reproducing
for a long time in the test tube.
Apart from saving animals, these
methods are cheaper and much quicker
than the animal methods that had
to be used in the past. Contrary
to what is sometimes suggested,
animal research is neither
a cheap nor easy option. - see
chart below
In the search for new medicines,
non-animal methods are used wherever
possible. In fact, modern pharmaceutical
industry research, as we know it
today, would not be possible without
such methods. By the time a potential
new medicine goes into the animal
testing stage of development, it
has already passed through
all the available non-animal methods.
Such methods are commonly referred
to as alternatives, a word which
may suggest that a researcher can
choose whether or not to
use them. In fact, there's no such
choice. The law controlling animal
research - known as the Animals
(Scientific Procedures) Act 1986
- forbids the use of animals if
other validated methods can provide
the required information.
These methods provide essential
information, but it is not nearly
comprehensive enough to make informed
decisions about whether, and in
what way, to take a new medicine
on into the human testing stage.
Because of the vast similarities
between our biology and the biology
of other animals, much of what we
cannot learn in test tubes and computer
studies can be predicted on the
basis of tests in animals.
Research is a slow, careful,
step-by-step process. The methods
that are used at each stage depend
on the biological questions that
need to be addressed.
| Research
in lower organisms
As
our knowledge has increased,
we have a much better
understanding of the
mechanisms common to
the whole living world.
It is increasingly possible
to undertake research
using lower organisms
such as bacteria and
yeast, invertebrates
and even immature life
forms such as chick
eggs and frog embryos.
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| Harmonising
regulations
The
Departments of Health,
along with the pharmaceutical
industries, of the USA,
European Union and Japan,
have been working towards
agreement on those tests
required by law. Although
the different governments
basically want the same
information, they sometimes
disagree on the specific
design and the way to
conduct a test. This
can force companies
to do separate tests
for different countries.
However, most of these
differences have already
been resolved, and work
continues towards the
goal of world-wide harmonisation.
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IN
TESTING A POSSIBLE MEDICINE,
IN VITRO TESTS
CAN
- tell
whether a new compound
has the desired effect
on isolated cells
or tissues, such as
artery muscle or kidney
cells
- show
certain hazards caused
by direct effects
on the cells
- suggest
the most promising
chemical leads to
follow
IN
VITRO TESTS CANNOT
- tell
whether the desired
effect will occur
in a complete living
system
- tell
whether the compound
will have a harmful
effect in a complete
living system
ANIMAL
TESTS CAN
- suggest
which compounds are
likely to be effective
in humans
- give
a strong indication
of which compounds
will not be harmful
to humans
ANIMAL
TESTS CANNOT
- predict
with absolute certainty
what will happen in
humans, nor are they
expected to. They
allow researchers
to get as close as
possible to the situation
in people before testing
an experimental medicine
in people.
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