Revival: Biological Effects of Low Level Exposures to Chemical and Radiation (1992)

12 BIOLOGICAL EFFECTS OF LOW LEVEL EXPOSURES

Interestingly, the concept of neotenous development in primates parallels

the view that the human infant is born “premature,” having completed only

about half its gestation period inside the womb (uterogestation), with

another 10 months required outside the womb (exterogestation).55 The rela­

tive helplessness of the exterogestation period can be presumed to end with

quadrupedal locomotion. Birth is simply a bridge between intra- and

extrauterine gestation. Human babies are born “prematurely” for two

reasons — large fetal brains and limitations on female pelvic size. It has been

speculated that the incongruities of exterogestation (omnipotent pleasure

indulgence vs powerless dependence on others) sow the seeds of human

conflict and neurosis.59

Scientifically, animals are utilized as biological models (surrogates) of

humans primarily because they function well at four levels of interest, that

is, at four different time scales:60 62

1. physicochemical (microseconds to minutes)


2. physiological (minutes to days)


3. morphogenetic (days to decades)


4. evolutionary (several lifetimes)

Because virtually all living things are made from cells, are based on the same

genetic code, and evolved by natural selection, and because all life is con­

nected,63 it would appear that all living things possess common controlling

elements capable of imposing fundamental and universal properties, includ­

ing aging.

Hypothesis IX: In eutherian mammalian species, exposures to particular,
nonessential, exogenous agents or stimuli capable of stressing the system,
produce a degree of instability that triggers a homeostatic, longevity hor-
metic response, temporarily (reversibly) reducing the sum total of injury
within the organism.

All living systems tend to maintain homeostasis, keeping an orderly bal­
ance among subsystems that process matter-energy or information.17 They
do so principally by employing pattern recognition and negative feedback;
pattern recognition extracts crucial information amidst a flood of irrelevant
signals, whereupon negative feedback acts on this information, returning
the system to near its original state. A system state is pathological (1) when
one or more of its variables perseveres beyond its range of stability for any
significant period of time, or ( 2 ) when the costs of adjusting an ailing
system are significantly increased. How efficiently a system adjusts is deter­
mined by what strategies are employed and whether they satisfactorily
reduce strains without being too costly. In the case of most noxious stimuli
exposure, the system cannot remove or circumvent them; consequently, its
only course of action is to master them in a cost-efficient fashion. Longev-