GROWTH INDUCED BY DAMAGE
29
such damage, brought about by an invading Ehrlich ascites tumor does
not result in an increase in mitotic activity in the cortex of the contralateral kidney (Table III). These lines of evidence suggest strongly
that the invading tumor does not affect the ability of the kidney cells
to respond to proper cues for growth and that the loss of mass is not one
of them.
TABLE
III
Mitotic Activity in the Left Kidney Cortex of Female Mice after Treatment to the
Right Kidney (Mice—without Colchicine Pretreatment)
a
Left kidney
Right kidney
No. mitoses
No. of
Days post100 000 cells
Treatment
mice
treatment
(Av. ± SE m )
&
None
11
2
5.5 ± 1.3
Sham operation
9
2
14.1 + 1.9
Damage (multiple needle insertions)
16
2
35.9 ± 5.8
Damage (single needle insertion)
6
2
12.0 ± 2.0
Unilateral nephrectomy
17
2
53.6 ± 6.7
Inoculation—Ehrlich ascites tumor
8
7
16.4 + 2.7
Saline injection under kidney capsule
12
7
14.8 ± 2.2
° From Argyris and Trimble (1964b).
6
Average ± standard error of the mean.
We have thus been led to conclude that the evidence implicating the
local loss of tissue mass as the stimulus for growth of the tissues surrounding damage (Bullough, 1962, 1965; Goss, 1964) is not conclusive.
It is our working hypothesis that the loss of mass is not the stimulus for
initiating damage-induced growth. The release of stimulating substances
is required. Unfortunately the evidence for this view is hardly more conclusive, but what there is will be presented below (Section IV,B).
3. Sublethal Intracellular
Damage as the Stimulus for the
Induction of Damage-Induced
Growth
Tsanev (1963) has studied the effects of pressure on epidermal growth
(Fig. 12). He has found that when pressure up to 15 kg/cm
2 is applied to
the dorsal skin of mice, the epidermal cells are induced to divide. But the
epidermal cells adjacent to the area under pressure are unaffected. If
the pressure is increased beyond 15 kg/cm
2 , the epidermal cells are
killed. The adjacent epidermal cells now show an increase in mitotic
29
such damage, brought about by an invading Ehrlich ascites tumor does
not result in an increase in mitotic activity in the cortex of the contralateral kidney (Table III). These lines of evidence suggest strongly
that the invading tumor does not affect the ability of the kidney cells
to respond to proper cues for growth and that the loss of mass is not one
of them.
TABLE
III
Mitotic Activity in the Left Kidney Cortex of Female Mice after Treatment to the
Right Kidney (Mice—without Colchicine Pretreatment)
a
Left kidney
Right kidney
No. mitoses
No. of
Days post100 000 cells
Treatment
mice
treatment
(Av. ± SE m )
&
None
11
2
5.5 ± 1.3
Sham operation
9
2
14.1 + 1.9
Damage (multiple needle insertions)
16
2
35.9 ± 5.8
Damage (single needle insertion)
6
2
12.0 ± 2.0
Unilateral nephrectomy
17
2
53.6 ± 6.7
Inoculation—Ehrlich ascites tumor
8
7
16.4 + 2.7
Saline injection under kidney capsule
12
7
14.8 ± 2.2
° From Argyris and Trimble (1964b).
6
Average ± standard error of the mean.
We have thus been led to conclude that the evidence implicating the
local loss of tissue mass as the stimulus for growth of the tissues surrounding damage (Bullough, 1962, 1965; Goss, 1964) is not conclusive.
It is our working hypothesis that the loss of mass is not the stimulus for
initiating damage-induced growth. The release of stimulating substances
is required. Unfortunately the evidence for this view is hardly more conclusive, but what there is will be presented below (Section IV,B).
3. Sublethal Intracellular
Damage as the Stimulus for the
Induction of Damage-Induced
Growth
Tsanev (1963) has studied the effects of pressure on epidermal growth
(Fig. 12). He has found that when pressure up to 15 kg/cm
2 is applied to
the dorsal skin of mice, the epidermal cells are induced to divide. But the
epidermal cells adjacent to the area under pressure are unaffected. If
the pressure is increased beyond 15 kg/cm
2 , the epidermal cells are
killed. The adjacent epidermal cells now show an increase in mitotic