170
LIONEL E. MAWDESLEY-THOMAS
aware, " Only man is like man ". Wellinga ( 1 969) in his excellent review
on neoplasiu in fish considered that fish tutnours were both analogous
and homologous to those in inan. A t this time it is felt that there is no
sufficient justification for this conclusion to be drawn.
While there are many reviews of bibliographies on the subject of
fish tuniours (Wellinga, 1969 ; Mawdesley-Thomas, 1969 ; 1971a, 1972),
some additional tumours seen at the Huntirigdon Research Centre will
be included in this chapter for the sake of completeness.
The increase of polychlorinated biphenyls (PCB) in such seas as the
Baltic and the North Sca is cause of concern to all conservationists.
The relationship between these compounds end neoplasia presents a
difficult problem and one which will not be readily resolved without the
establishmelit of a multi-national interdisciplinary group of scientists.
The problems of biological concentration have still to be evaluated, and
this is particularly true of the clams and oysters, and many species
of fish which are at predator pinnacles (Mawdesley-Thomas and Leahy,
1967). Migratory species, such a : many of the Salmonidae, which
build up large reserves of fat, can soon raise their serum level of some
of these chemicals, many of which are lipid soluble (e.g. the organochlorines), to toxic levels. Among the birds the same can be said of
the arctic tern (Sterna macrura Naum), which has the longest migratory
passage of any known bird.
*
The largest subdivision of the Vcrtebratu includes the fishes and
it is not surprising that there are biochemical and enzymatic differences
betwcen species and sub-specirs. The presence or absence of EL particular
enzyme system may detcrmiiic it specific metabolic pathway in relation
to exogenous compountls. It is important to establish chemicaIIy
whether a proximate carcinogen is found or not. It has already been
shown that enzymatic differences occur betwcen sub-species of the
Salmonidue (Mawdesloy-Thomas und Harry, 1970). It is k~y defining
such cherniral details that the difficulties associatcvl with species
differences will ultimately be solved. The morphologist must become
more chemically and biochemically orientated if he is to become fully
integrated into the present-day problems associated with neoplasia.
This type of lateral thinking could ultimately explain the differences in
the reaction to aflatoxiti B,, which causes 100% tumours in rainbow
trout when fed a diet containing one part per lo8, whereas brown trout
are virtually resistant to it. The presence or absence of certain enzymes
or iso-enzyme systems reflects, or may reflect, the genetic make-up.
The itnportantI part played by oncogenio viruses in neoplastic disease
in animals is being increasingly realized, (Wolf, 1!)72 ; MawdesleyThomas, 1 !)7% 1973 ; hl;~wdexlcy-'i'horn;~s and Bucke, I 97:3), itnd great
LIONEL E. MAWDESLEY-THOMAS
aware, " Only man is like man ". Wellinga ( 1 969) in his excellent review
on neoplasiu in fish considered that fish tutnours were both analogous
and homologous to those in inan. A t this time it is felt that there is no
sufficient justification for this conclusion to be drawn.
While there are many reviews of bibliographies on the subject of
fish tuniours (Wellinga, 1969 ; Mawdesley-Thomas, 1969 ; 1971a, 1972),
some additional tumours seen at the Huntirigdon Research Centre will
be included in this chapter for the sake of completeness.
The increase of polychlorinated biphenyls (PCB) in such seas as the
Baltic and the North Sca is cause of concern to all conservationists.
The relationship between these compounds end neoplasia presents a
difficult problem and one which will not be readily resolved without the
establishmelit of a multi-national interdisciplinary group of scientists.
The problems of biological concentration have still to be evaluated, and
this is particularly true of the clams and oysters, and many species
of fish which are at predator pinnacles (Mawdesley-Thomas and Leahy,
1967). Migratory species, such a : many of the Salmonidae, which
build up large reserves of fat, can soon raise their serum level of some
of these chemicals, many of which are lipid soluble (e.g. the organochlorines), to toxic levels. Among the birds the same can be said of
the arctic tern (Sterna macrura Naum), which has the longest migratory
passage of any known bird.
*
The largest subdivision of the Vcrtebratu includes the fishes and
it is not surprising that there are biochemical and enzymatic differences
betwcen species and sub-specirs. The presence or absence of EL particular
enzyme system may detcrmiiic it specific metabolic pathway in relation
to exogenous compountls. It is important to establish chemicaIIy
whether a proximate carcinogen is found or not. It has already been
shown that enzymatic differences occur betwcen sub-species of the
Salmonidue (Mawdesloy-Thomas und Harry, 1970). It is k~y defining
such cherniral details that the difficulties associatcvl with species
differences will ultimately be solved. The morphologist must become
more chemically and biochemically orientated if he is to become fully
integrated into the present-day problems associated with neoplasia.
This type of lateral thinking could ultimately explain the differences in
the reaction to aflatoxiti B,, which causes 100% tumours in rainbow
trout when fed a diet containing one part per lo8, whereas brown trout
are virtually resistant to it. The presence or absence of certain enzymes
or iso-enzyme systems reflects, or may reflect, the genetic make-up.
The itnportantI part played by oncogenio viruses in neoplastic disease
in animals is being increasingly realized, (Wolf, 1!)72 ; MawdesleyThomas, 1 !)7% 1973 ; hl;~wdexlcy-'i'horn;~s and Bucke, I 97:3), itnd great