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Fig. 2. Photographs showing the CAFCA accessories.
(A)
Top and bottom 6-well
CAFCA miniplates having two parallel grooves (1 mm large and 2 mm deep) on each
side of the wells. Note that the bottom CAFCA miniplate is provided with an adhesive
surface.
(B)
CAFCA holders in black hard plastic to be used as centrifugation and fluo-
rescence detection supports.
chosen time-intervals, or continuously in real-time by utilizing video time-lapse
microscopy in conjunction with light-sensitive CCD cameras
(7
,
26
,
27)
or, pref-
erably, by computer-assisted confocal laser microscopy systems (
28
,
29
; mul-
tiple photon confocal laser microscopes are currently available that cause
minimal fluorescence fading during continuous cell tracking). These latter
microscopic systems have the additional potential to allow for true 4-dimen-
sional analyses
(30)
. The common final goal of both types of analyses is to
be able to score the depth at which the invading cells localize within the
3-dimensional matrix, and the relative speed with which they accomplish this
movement. Establishment of these two quantitative parameters provides a mea-
sure for the invasive capability of the cells.
It is implicit that both qualitatively and quantitatively the mechanisms of
cell locomotion are most accurately analyzed utilizing the aforementioned
methods. However, these cannot efficaciously be applied to the rapid and eas-
ily performed screening tests, because they are laborious, time-consuming, and
invariably involve the use of sophisticated instruments. Thus, the classical
Boyden chambers, and their more recent derivatives, the so-called Transwells,
provide alternative means of assessing cell motility in vitro. Originally, these
systems were intended for the quantification of the chemotactic motility
response of leukocytes
(31-35)
, but later were demonstrated also to be suitable
for the assessment of similar phenomena in mesenchymal and epithelial cells
(36-38)
. Assays involving the use of Transwells are all based on the passage of
cells through a porous, inert micromembrane of polycarbonate or polypropy-
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