WALTER H. SEEGERS 
497 
DAYS HOURS 
Figure 4. — Prothrombin time, two-stage prothrombin 
assay, and autoprothrombin III concentration in the 
plasma of an 18 kg. dog. On successive days 100, 75, 
and 50 mg Dicumarol were given. Then, the effect 
•was reversed by the intravenous infusion of vitamin 
K,. 
proenzymes diminished at the same rate over a 
period of four days. The antagonist completely 
suppressed the synthesis of the vitamin K de- 
pendent protein (s). When vitamin K v^^as then 
given intravenously to overcome the inhibition, 
an increase in the concentration of plasma 
prothrombin was already noticed vs^ithin one 
hour. The upv^ard trend continued during the 
five hours of observation. By using fluorescent 
antibodies for prothrombin, it was demon- 
strated that fluorescence could be seen on liver 
parenchymal cells within 30 to 60 minutes after 
the administration of vitamin K.^^ really 
marvelous to observe the control of special pro- 
tein synthesis in this way. It has been calcu- 
lated that 1.27 X 10^^ prothrombin molecules 
were synthesized per minute after the vitamin 
K was given. It has a molecular weight of about 
69,000 and is only a part of the prothrombin 
complex. It is hard to comprehend how so many 
amino acids find their proper place so rapidly. 
Another special feature of this experiment il- 
lustrates that the prothrombin time is no indi- 
cator of prothrombin or autoprothrombin III 
concentration during the period when vitamin 
K initiates the synthesis. No one has produced 
data to explain the peculiar response of the 
prothrombin time. In perfusion experiments, 
livers have been taken from animals previously 
treated with Dicumarol and a shortening of the 
prothrombin time has been observed. Various 
contradictory interpretations have been given 
to the results. 
The experiment of 1968, illustrated by means 
of Figure 4, was possible because Dicumarol 
and vitamin K were available in bottles. Many 
years before that, namely, in 1938, I partici- 
pated in an experiment that took 750 days in- 
stead of five.^^ By surgical procedures on a dog, 
we arranged to have the bile drain through the 
kidney and out with the urine. As a conse- 
quence, the fat-soluble vitamin K was not well 
absorbed and a prothrombin deficiency devel- 
oped (Figure 5). When bile was fed, the defi- 
ciency slowly subsided and developed once more 
when the bile was not fed. This experiment 
alerted investigators to the possibility that vi- 
tamin K might be useful for human beings af- 
flicted with obstructive jaundice. 
An important biological phenomenon for ani- 
mals and man is STRESS. The great contribu- 
tion of Hans Selye was his demonstration that 
stress produces changes in many body organs 
and tissues of rats and that these changes are 
frequently adverse. A problem with the use of 
drugs, which inhibit blood coagulation or affect 
platelets, and problems with various conditions 
(e.g., hemophilia) which have the same result, 
is that hemorrhage can result in an unpredict- 
able manner. Louis B. Jaques and associates 
"-1^ have shown, with the use of rats, that 
this is due to accompanying stress. This pro- 
vides one of the simplest ways of demonstrating 
and studying stress in animals. When an anti- 
coagulant was administered and the animals 
were stressed, most of them developed symp- 
toms of internal hemorrhage in four or five 
days, and this was measured by the incidence of 
such hemorrhage, degree of hemorrhage or 
mortality from hemorrhage. In this way, stress 
was demonstrated to have occurred in rats ex- 
posed to confinement, electroshock, psychologi- 
cal conditioning procedures, many drugs (in- 
cluding anesthetics), injection procedures, etc. 
Even handling of older rats to receive a subcu- 
taneous injection twice a day proved to be a 
stress. This is an example of how animal studies 
can throw light on a serious clinical problem 
which is resistant to analysis clinically. 
