PHARMACOLOGY 
752 
developed during the past 10-15 years, how- 
ever, is directly attributable to the advent and 
extent of open heart surgical procedures in 
man. The widespread application of open heart 
surgery has added a new dimension for the in- 
vestigator specializing in in vitro techniques. 
The reason is that he now is able to routinely 
and conveniently obtain freshly biopsied seg- 
ments of the human heart which become avail- 
able as the result of surgical interventions. 
Table VIII summarizes a few of the types of 
human cardiac tissues employed in recent years 
for in vitro physiological, pharmacological and 
biochemical studies. Significantly, human car- 
diac tissues from human foetuses obtained from 
elective abortion procedures may add still an- 
other dimension to in vitro studies of human 
tissue. 
Our own experience during the past 14 years 
has been mostly with the use of human right 
and left atrial tissue obtained upon commence- 
ment of total cardiopulmonary bypass proce- 
dures. We have used this tissue over preference 
to papillary muscle for several reasons. Some of 
these are listed in Table IX. These listed advan- 
tages of atrial tissue are applicable also to the 
selection of animal atrial preparations. 
ISOLATED HUMAN SAPHENOUS VEINS 
In 1964 we reported on the use of fresh, biop- 
sied human veins for routine investigations in 
the pharmacology laboratory. During the inter- 
vening years, we have been able to expand our 
investigations to the use of both normal and 
Table VIII. — Examples of Human Heart Tissues 
Studied in Vitro 
Tissue Investigator* 
Left Atrium Levy 
Sleator et al. 
van Dam & Durrer 
Right Atrium Levy 
Sleator et al. 
Noren et al. 
Ko & Paradise 
Right Papillary (RV) Chidsey et al. 
Prasad et al. 
Trabeculae Carneae (RV) Trautwein et al. 
Papillary (human foetuses) Gennser & Nilsson 
Trabeculae muscle (post mort.) Ullrick 
• See References 
Table IX. — Some Advantages of Isolated Atrial 
Preparations 
1. Thinness permits good O2 diffusion. 
2. Extensive tissue trimming or slicing unnecessary. 
3. Uniformity of tissue size. 
4. Adequate tension development. 
5. Easy separation of right and left atria. 
6. Size and shape eliminates need for ties and ligatures for mount- 
ing. 
7. Stable contractile tension following equilibration. 
8. Abundant adrenergic and cholinergic innervation. 
9. Tissue size permits biochemical and chemical analyses without 
tissue pooling. 
varicosed vein tissue. Our most recent work has 
involved the use of saphenous vein segments ob- 
tained from patients undergoing aortocoronary 
vein bypass surgery. 
We have utilized the helically cut vein strip 
preparation which was developed earlier for use 
with rabbit aortic strips. 
While the human vein preparation has 
yielded results that are generally qualitatively 
and quantitatively similar to results obtained 
with animal arterial tissue, there are some im- 
portant features of the vein which necessarily 
preclude applying or extrapolating results to 
other vascular tissues. Of course, other human 
vascular tissues can be obtained from a variety 
of surgical procedures. The use of other human 
vascular preparations for in vitro study has 
been reported. 
SUMMARY 
A survey has been made of the use, advan- 
tages and limitations of isolated animal and 
human myocardial and vascular tissue for in 
vitro investigations. Important qualitative and 
quantitative differences and similarities in 
human and animal tissues' responses to various 
substances are described. 
The diversity of data suggest these important 
points : It is not wise to use and depend on one 
kind of in vitro preparation in characterizing 
the action of any given agent. Use of function- 
ally deranged (natural or experimentally 
induced) animal tissues does not necessarily 
mimick the same disease or derangement in man, 
or predict responses to drugs in the intact organ- 
ism. 
