118 • Alternatives to Animal Use in Research, Testing, and Education 
Figure 6-1.— Apparatus for Remote Blood-Sampling 
via Chronic, Intravascular Catheter 
From Unrestrained Ferret 
the production of target -specific monoclonal anti- 
bodies has improved the ability of external radio - 
imaging techniques to locate tumors and to iden- 
tify certain noncancerous diseases; radiolabeled 
antibodies attach to the target tissue and are then 
visualized (59). Amniocentesis is used for the early 
detection of genetic diseases, teratological events, 
and fetal distress, particularly in domestic species 
(67). A new application of the laser in oncology 
involves its ability to initiate a lethal photochemi- 
cal reaction in cancerous tissue during photoradi- 
ation therapy (41). 
USE OF LIVING SYSTEMS 
In Vitro Research 
In vitro biomedical research entails the mainte- 
nance of organs, tissues (or fragments of organs 
and tissues), and cells outside of the body . Depend- 
ing on the conditions of harvesting and preparing 
the living material for in vitro maintenance, the 
cells may be grown as a population of independ- 
ent cells (cell culture) or with the normal tissue 
or organ architecture preserved. In the former, 
Some apparently new noninvasive techniques 
are actually adapted, miniaturized, or computer- 
ized versions of older methods. One such exam- 
ple is a small, inflatable tail cuff used to measure 
blood pressure in a rat’s tail during hypertension 
studies (225). In another example, urine is used 
in some specialized methods: In physiological re- 
search, electrical impedance measures canine uri- 
nary output (1). 
Tandem mass spectrometry is being used for 
breath analysis to screen for diabetes, cirrhosis, 
renal disease, and ovulation. Many diseases remain 
to be examined, but there is potential for use of 
this technique in toxicology, nutrition, metabolic 
diseases, endocrinology, anesthesia, physiology, 
and pathology (133). 
A technique developed for the determination of 
the quality of agricultural crops (162) and the per- 
cent of fat in beef (135) uses amplified, digitized, 
computer-corrected diffuse reflectance spectro- 
photometry in the near -infrared region. It involves 
simply placing an appropriate sensor on the sur- 
face of the skin and it can be adapted for oncologi- 
cal, physiological, and nutritional research (102). 
Other increasingly popular noninvasive tech- 
niques include ultrasonography— which is used 
in cardiology to locate vessels (145), to determine 
blood-flow velocity (176), and to detect early ath- 
erosclerosis (108)— and magnetic resonance imag- 
ing, used to examine the energetics of skeletal mus- 
cle in gerontological research (201), to diagnose 
metabolic disorders (32), and to provide details of 
molecular structure and dynamics in liquids and 
solids (130). 
BIOMEDICAL RESEARCH 
the cells may be encouraged to proliferate, result- 
ing in numerous descendant cell populations suit- 
able for studies on growth, nutrition, cell division, 
and gene expression and regulation. 
Table 6-2, which summarizes the characteris- 
tics of in vitro systems, makes it clear that as orga- 
nization is disrupted or lost, the in vitro system 
has less and less of the kind of intercellular and 
intracellular interactions that characterize organs, 
