40
A . M O S C O N A , O . A . T R O W E L L A N D E . N . W I L L M E R
above and below. In a plasma clot, held between the two coverslips,
layers of cells tend to form on both the plasma—glass interfaces, and
one layer tends to interfere with the observation of the other. Thus
to confine the cells in sandwiches of very well-washed and sterilized
Cellophane (Rose, 1962), or between such Cellophane on the one side
and glass or Plexiglass on the other, or between a serum-agar gel and
the glass (Pulvertaft et aL, 1956), so that they can form only a single
layer, has definite advantages; these accrue not only from the optical
point of view but also because these barriers allow the cells to maintain
their own fluid environments more constant, particularly with regard
to the larger molecules, though the smaller metabolites may come and
go fairly freely. On the other hand, this close proximity of flat inert
surfaces, particularly of Cellophane, may cause abnormal behaviour,
including the formation of giant cells, to occur even more readily than
it does in a plasma clot, for example. Such perfusion chambers are
admirable for the study of the visible reactions of cells to the conditions
in the culture, and to perfusion with various metabolic stimulants and
poisons, drugs, hormones etc. The fluid which is drawn off can of course
be analysed, but generally the volumes are small and the circulation
in the chamber is apt to be somewhat irregular both in space and time,
so that the concentrations found may not be those in the immediate
neighbourhood of the tissues.
The perfusion system used by Buchsbaum and Kuntz (1954) seems
to be admirably suited to such studies on the effects of reagents on
isolated cells. The use of the cine-camera or other time-lapse recording
device in connexion with such observations is very advantageous. The
following phenomena, to mention but a few among many, have been
discovered or elucidated by the use of such methods: the rotation of
nuclei within epithelial and nerve cells (Pomerat, 1952, 1961), the
periodic contractile activity of oligodendrocytes (Pomerat, 1952),
the sequence of events in pinocytosis (Rose, 1957), and a similar phenomenon in the growing neurites of nerve cells (Hughes, 1953), the
undulating lamelliform membranes of astrocytes and their rapid
change to a radial system of pseudopodia (Pomerat, 1952), and the
movement, fragmentation and change of form of mitochondria
(Strangeways and Canti, 1927; Godina, 1962). Similarly, it may be
very difficult to determine whether a given cell is a lymphocyte or a
monocyte by direct microscopic observations of static or fixed cells,
but the cine-camera applied to such cells living in slide chambers
reveals immediately a different type of movement for each. Although
perhaps some of these observations could be made by other methods,
the recording camera combined with the perfusion chamber or slide
chamber is a singularly powerful and helpful tool.
A . M O S C O N A , O . A . T R O W E L L A N D E . N . W I L L M E R
above and below. In a plasma clot, held between the two coverslips,
layers of cells tend to form on both the plasma—glass interfaces, and
one layer tends to interfere with the observation of the other. Thus
to confine the cells in sandwiches of very well-washed and sterilized
Cellophane (Rose, 1962), or between such Cellophane on the one side
and glass or Plexiglass on the other, or between a serum-agar gel and
the glass (Pulvertaft et aL, 1956), so that they can form only a single
layer, has definite advantages; these accrue not only from the optical
point of view but also because these barriers allow the cells to maintain
their own fluid environments more constant, particularly with regard
to the larger molecules, though the smaller metabolites may come and
go fairly freely. On the other hand, this close proximity of flat inert
surfaces, particularly of Cellophane, may cause abnormal behaviour,
including the formation of giant cells, to occur even more readily than
it does in a plasma clot, for example. Such perfusion chambers are
admirable for the study of the visible reactions of cells to the conditions
in the culture, and to perfusion with various metabolic stimulants and
poisons, drugs, hormones etc. The fluid which is drawn off can of course
be analysed, but generally the volumes are small and the circulation
in the chamber is apt to be somewhat irregular both in space and time,
so that the concentrations found may not be those in the immediate
neighbourhood of the tissues.
The perfusion system used by Buchsbaum and Kuntz (1954) seems
to be admirably suited to such studies on the effects of reagents on
isolated cells. The use of the cine-camera or other time-lapse recording
device in connexion with such observations is very advantageous. The
following phenomena, to mention but a few among many, have been
discovered or elucidated by the use of such methods: the rotation of
nuclei within epithelial and nerve cells (Pomerat, 1952, 1961), the
periodic contractile activity of oligodendrocytes (Pomerat, 1952),
the sequence of events in pinocytosis (Rose, 1957), and a similar phenomenon in the growing neurites of nerve cells (Hughes, 1953), the
undulating lamelliform membranes of astrocytes and their rapid
change to a radial system of pseudopodia (Pomerat, 1952), and the
movement, fragmentation and change of form of mitochondria
(Strangeways and Canti, 1927; Godina, 1962). Similarly, it may be
very difficult to determine whether a given cell is a lymphocyte or a
monocyte by direct microscopic observations of static or fixed cells,
but the cine-camera applied to such cells living in slide chambers
reveals immediately a different type of movement for each. Although
perhaps some of these observations could be made by other methods,
the recording camera combined with the perfusion chamber or slide
chamber is a singularly powerful and helpful tool.