150
D. ADAMIKER
References
1. KURIAKI, K., and CH. J. KENSLER: ]. Biochem. (Tokyo) 41, 409 (1957).
2. LAZOVSKAYA, L. N.: Biochimia (Russ.) 8, 171 (1943).
3. LEIBETSEDER, J.: Z. Altersforsch. 15, 210 (1961).
4. LINDER, G.: Vet. Med. Diss. Wien (1961).
5. NOVIKOFF, A. B., In: (J. BRACHET and A. E. MIRSKY, Eds.) The Cell Vol. II.
New York and London: Academic Press 1961.
6. SAMSON, E. F., M. BALFOUR and R. JACOBS: Amer. J. Physiol. 199, 693 (1960).
Discussion
SMITH:
Were control tests performed to eliminate variance due to different degrees of
shrinkage in cell areas of the tissue of the young animals in comparison with
that of the older group; e.g. could there have been more lipid or water in the
cells of one but not the other group, which might have caused a difference in
apparent cell size and/or mitochondrial size? If your data, however, show
differences obviously greater than could be attributed to these effects, it
would appear that your conclusions are probably quite valid. From some
early work done in our laboratory some years ago (unpublished) I can state that
our results agree with your present conclusions.
HORWITZ:
As an addendum to Dr. SMITH'S comment, I would like to say that I have
observed similar changes in number and size of liver mitochondria in rats
acclimated to cold (unpublished data). However, changes in the content of
tissue water were also observed and these could explain-to a large degreethe increases in mitochondria number per unit area. On the other hand, if the
differences you observed were relatively large (i. e., of the order of 2 or more
fold) it is unlikely that a decrease in water content of the tissues could account
for your changes.
ADAMIKER:
We have done no other quantitative experiments or control tests except the
measurements of mitochondria. But so far as the normal appearance of the cell
could be a point, we did not see any abnormalities between the cells of younger
or older rats. Both type of cells were at the same magnification of about the
same size and there was no remarkable difference in the lipid or water content.
The significant difference between the values of the young and olds rats was
so high (~0.001) that water loss alone could not explain the differences.
D. ADAMIKER
References
1. KURIAKI, K., and CH. J. KENSLER: ]. Biochem. (Tokyo) 41, 409 (1957).
2. LAZOVSKAYA, L. N.: Biochimia (Russ.) 8, 171 (1943).
3. LEIBETSEDER, J.: Z. Altersforsch. 15, 210 (1961).
4. LINDER, G.: Vet. Med. Diss. Wien (1961).
5. NOVIKOFF, A. B., In: (J. BRACHET and A. E. MIRSKY, Eds.) The Cell Vol. II.
New York and London: Academic Press 1961.
6. SAMSON, E. F., M. BALFOUR and R. JACOBS: Amer. J. Physiol. 199, 693 (1960).
Discussion
SMITH:
Were control tests performed to eliminate variance due to different degrees of
shrinkage in cell areas of the tissue of the young animals in comparison with
that of the older group; e.g. could there have been more lipid or water in the
cells of one but not the other group, which might have caused a difference in
apparent cell size and/or mitochondrial size? If your data, however, show
differences obviously greater than could be attributed to these effects, it
would appear that your conclusions are probably quite valid. From some
early work done in our laboratory some years ago (unpublished) I can state that
our results agree with your present conclusions.
HORWITZ:
As an addendum to Dr. SMITH'S comment, I would like to say that I have
observed similar changes in number and size of liver mitochondria in rats
acclimated to cold (unpublished data). However, changes in the content of
tissue water were also observed and these could explain-to a large degreethe increases in mitochondria number per unit area. On the other hand, if the
differences you observed were relatively large (i. e., of the order of 2 or more
fold) it is unlikely that a decrease in water content of the tissues could account
for your changes.
ADAMIKER:
We have done no other quantitative experiments or control tests except the
measurements of mitochondria. But so far as the normal appearance of the cell
could be a point, we did not see any abnormalities between the cells of younger
or older rats. Both type of cells were at the same magnification of about the
same size and there was no remarkable difference in the lipid or water content.
The significant difference between the values of the young and olds rats was
so high (~0.001) that water loss alone could not explain the differences.