200 
PULMONARY MODELS 
J. D. Effects of mild chronic hypoxia on the pul- 
monary circulation in calves with reactive pulmon- 
ary hypertension. Circulat. Res. 21:661-669, 1967. 
5. Alexander, A. F., and Jensen, R. Pulmonary ar- 
teriographic studies of bovine high mountain dis- 
ease. Amer. J. Vet. Res. 24:1094-1097, 1963. 
6. Alexander, A. F., and Jensen, R. Pulmonary 
vascular pathology of bovine high mountain dis- 
ease. Amer. J. Vet. Res. 24:1098-1111, 1963. 
7. Alexander, A. F., and Jensen, R. Pulmonary 
vascular pathology of high altitude induced pul- 
monary hypertension in cattle. Amer. J. Vet. Res. 
24:1112-1122, 1963. 
8. Will, D. H., Alexander, A. F., Reeves, J. T., 
and Grover, R. F. High altitude induced pulmon- 
ary hypertension in normal cattle. Circ. Res. 
10:172-177, 1962. 
9. Grover, R. F., Reeves, J. T., Will, D. H., and 
Blount, S. G., Jr. Pulmonary vasoconstriction in 
steers at high altitude. J. appl. Physiol. 
18:567-574. 
10. Will, D. H., Horrell, J. F., and Alexander, A. 
F. Pulmonary arterial pressure in cattle residing at 
different altitudes. In preparation. 
11. Will, D. H., Card, C. S., Vanlandingham, G. D., 
and Alexander, A. F. Cardiorespiratory responses 
of two "genetic" types of cattle to hypobaria. Phys- 
iologist 10 : 347, 1967. 
12. Will, D. H., Hicks, J. L., Card, C. S., and 
Alexander, A. F. Genetic basis for high altitude 
adaptation in cattle. Fed. Proc. 29:591, 1970. 
13. GOWEN, J. W. Experimental analysis of genetic 
determinants in resistance to infectious disease. 
Anal. N. Y. Acad. Sci. 91:689-709, 1961. 
14. Eaton, J, W., Brewer, G. J., and Grover, R. F. 
Role of red cell 2,3-diphosphoglycerate in adapta- 
tion of men to altitude. J. Lab. Clin. Med. 73:603- 
609, 1969. 
15. Lenfant, C, Torrance, J. D., and Finch, C. A. 
The regulation of hemoglobin affinity for oxygen 
in man. Tr. Ass. Am. Phys. 82:121-128, 1969. 
16. Cueva, S., and Will, D. H. Blood oxygen trans- 
port in cattle "susceptible" and "resistant" to high 
mountain disease. In Current Research in Chronic 
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U. S. Public Health Service, 1968. 
17. Hicks, J. L. Effects of altitude on bovine blood 
oxygen transport. Ph.D. dissertation, Colorado 
State University, Fort Collins, Colorado, 1971. 
18. Card, C. S. The response of the bovine erythron to 
hypoxic stress. Ph.D. dissertation, Colorado State 
University, Fort Collins, Colorado, in preparation. 
19. Heath, D., and Edwards, J. E. The pathology of 
hypertensive pulmonary vascular disease. Circ. 
18:533-547, 1958. 
20. Wagenvoort, C. A. Vasoconstriction and medial 
hypertrophy in pulmonary hypertension. Circ. 
23:740-748, 1961. 
21. Arias-Stella, J., and Saldana, M. The terminal 
portion of the pulmonary arterial tree in people na- 
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22. Hasleton, P. S., Heath, D., and Brewer, D. B. 
Hypertensive pulmonary vascular disease in states 
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1968. 
23. Spiro, D., Lattes, R. D., and Wiener, J. The cel- 
lular pathology of experimental hypertension. 
Amer. J. Path. 47:19-49, 1965. 
24. Gardner, D. L., and Mathews, M. A. Ultrastructure 
of the wall of small arteries in early experimental 
rat hypertension. J. Path. 97:51-62, 1969. 
25. McGee, W. G., and Ashworth, C. T. Fine struc- 
ture of chronic hypertensive arteriopathy in the 
human kidney. Am. J. Path. 43:273-299, 1963. 
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DISCUSSION 
J. T. Reeves, University of Kentucky, Lex- 
ington, Kentucky: Many of us have av^^aited 
these findings with considerable interest. It is 
very nice to see the results of this study of bo- 
vine families at high altitudes. The possibility 
that the pulmonary hypertension relates to hy- 
poventilation, as opposed to increased reactivity 
of the pulmonary vessels, could be decided very 
nicely if the PO2, perhaps even the alveolar 
PO2, were kept constant given hypoxic stimu- 
lus. I wonder if you have any idea about that? 
Dr. Alexander : No I don't. 
Gerald Moss, Rennselaer Polytechnic Insti- 
tute, Troy, N.Y. : Along the lines that were just 
brought up. Dr. Alexander, we've been working 
with calves breathing room (ambient pressure) 
air ; but with an isolated brain percussion with 
a hypoxemic profusion (simulating acutely very 
high altitudes, about 30-35 mm. of mercury ox- 
ygen), and within minutes we get pulmonary 
arterial hypertension. We also get severe lung 
changes, but we get a reactive thing which ap- 
pears to be central neurogenic. 
I was interested in those electron micro- 
graphs and I'm not sure I understood. Is it true 
that you think that the animals which are hy- 
per-responders have evidence of more damage 
in the organelles? Can you explain that a little 
bit more ? 
Dr. Alexander : No, not as a difference be- 
tween the groups. It was as a difference be- 
tween the normal tensive animal in the group. 
