U.S. patent number 3,892,197 [Application Number 05/463,055] was granted by the patent office on 1975-07-01 for light microscopy processing apparatus.
Invention is credited to Thomas D. Kinney, John E. P. Pickett.
United States Patent |
3,892,197 |
Kinney , et al. |
July 1, 1975 |
Light microscopy processing apparatus
Abstract
A tissue processor provides a closed system for sequentially
immersing light microscopy tissue specimens in treating fluids
preparatory to embedding or in staining fluids. Treating or
staining fluids, including paraffin, are drawn into the processing
chamber by use of vacuum and are forced back to their respective
containers by use of pressure and the specimens remain
substantially stationary throughout the fluid treatment.
Inventors: |
Kinney; Thomas D. (Durham,
NC), Pickett; John E. P. (Durham, NC) |
Family
ID: |
23838706 |
Appl.
No.: |
05/463,055 |
Filed: |
April 22, 1974 |
Current U.S.
Class: |
118/667; 118/429;
118/50; 118/500 |
Current CPC
Class: |
D06B
23/10 (20130101); G01N 1/31 (20130101); G01N
2001/315 (20130101) |
Current International
Class: |
D06B
23/00 (20060101); D06B 23/10 (20060101); G01N
1/31 (20060101); G01N 1/30 (20060101); B05c
003/109 () |
Field of
Search: |
;118/7,10,11,50,429,500 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rimrodt; Louis K.
Assistant Examiner: Salser; Douglas
Claims
What is claimed is:
1. A closed processing system enabling a plurality of individual
specimens of tissue to be separately contained while being bathed
simultaneously for varying lengths of time in successive selected
tissue solutions including melted paraffin so as to fix, dehydrate
and clear the specimens preparatory to embedding, comprising:
a. a plurality of uniform tissue receptacles each being adapted to
contain and physically isolate a group of tissue specimens having
at least one specimen per group, each receptacle having a body
portion defining an open cavity adapted to receive and retain
specimens and closure means removably received by said body to
enclose said cavity, the material forming said receptacles being
inert to all of said solutions and having for each of said
solutions at least some portion through which each of said
solutions may be transferred;
b. a cabinet;
c. an electrically heated, temperature controlled container mounted
in said cabinet and having a movable cover and being adapted for
melting and holding melted paraffin;
d. a plurality of closed solution containers mounted in
predetermined order in a storage compartment in said cabinet
proximate said paraffin container, each solution container
containing a particular tissue processing solution and with said
melted paraffin container collectively containing all of the said
tissue solutions in which said specimens are processed;
e. air pump means having associated remotely electrically
controllable first valve means mounted proximate said cabinet and
associated interconnected piping means, said pump means providing a
pressure and vacuum source and said first valve means being
selectively operable to connect said source whereby to produce a
selected pressure or vacuum condition in said piping means;
f. a processing chamber mounted in said chamber and having an end
wall immediately adjacent an end wall of said melted paraffin
container, said chamber having a pressure sealable top cover and
being adapted to receive and process therein selected numbers of
said receptacles simultaneously said chamber being temperature
controlled and electrically heated and being connected to said
piping means thereby enabling the corresponding selected pressure
and vacuum condition in said piping means to be produced in said
chamber;
g. a second remotely electrically controllable valve means mounted
in said cabinet and having on one side a fluid connection to said
chamber and on the other side a fluid connection to said paraffin
container enabling the paraffin contents thereof to be exchanged
between the chamber and said paraffin container, said fluid
connections for said second valve means being of minimal length and
being electrically heated and maintained at a temperature above the
melting point of said paraffin;
h. a third remotely electrically controllable valve means mounted
in said cabinet and having on one side a fluid connection of
minimal length to said chamber and on the other side a port for
transfer of solutions therethrough;
i. fourth remotely electrically controllable solution transfer
valve means positioned in said cabinet between said processing
chamber and said storage compartment, said fourth valve means being
fluid connected on one side to said third valve transfer port and
on the other side having separate fluid connections to each of said
solution containers and being remotely electrically controllable
for enabling each solution container connection on the one side of
the fourth valve means to be selectively and independently
connected to said transfer port for a predetermined time while all
other solution container connections are isolated therefrom and at
other times to isolate all of said solution container connections
from said tranfer port;
j. an electrical power source; and
k. remotely operable electrical control means connected to said
power source and mounted proximate said chamber for remotely
powering and electrically operating each of said valve means and
temperature controls in a predetermined time sequence program
whereby with a selected number of said receptacles installed in
said chamber and said cover sealed on said chamber, said solutions
and said paraffin are successively, selectively and independently
drawn from said solution and paraffin containers, are measured by
timing the withdrawal and admitted to said chamber under a vacuum
condition in a predetermined volume, retained for predetermined
times at a predetermined pressure and at the end of each processing
step being forced back to a respective said solution and paraffin
container by pressure from said pump means source in a
corresponding processing sequence such that selected of said
solutions and said melted paraffin are separately and independently
exchanged with each said group of specimens while maintaining said
system closed, said paraffin transferred a minimal distance, and
each said group physically isolated.
2. In a system as claimed in claim 1 including:
a. a second said heated and temperature controlled paraffin
container, said first and second paraffin containers being
laterally spaced and positioned immediately adjacent said chamber
with said paraffin containers and chamber being below and foward of
said compartment containing said solution containers in said
cabinet, and
b. a sixth remotely controllable valve means closely connected to
second paraffin container and comparable in position and function
to said second valve means for said first container thus enabling
the melted paraffin contents of either said first or second
paraffin container to be selectively exchanged with the chamber
through a path of minimal distance.
3. In a system as claimed in claim 2 wherein said second and sixth
valve means are submerged in the respective said first and second
melted paraffin containers and in immediate proximity to the
respective paraffin container bottom walls and proximate the end
walls separating the paraffin containers and chamber, said end
walls having respective ports connected to the respective second
and sixth valve means enabling the respective melted paraffin
contents to be transferred directly and under remote control
between said paraffin containers and chamber through said
ports.
4. In a system as claimed in claim 1 wherein said fourth valve
means comprises a remotely electrically controllable rotary type
valve.
5. In a system as claimed in claim 1 wherein said paraffin
container temperature control comprises a two stage control for
obtaining different degrees of heat in said paraffin container and
said control means controls the energization of each such stage in
a timed sequence.
6. In a system as claimed in claim 2 wherein each said paraffin
container temperature control comprises a two stage control for
obtaining different degrees of heat in said paraffin container and
said control means controls the energization of each such stage in
a timed sequence.
7. In a system as claimed in claim 2 including in said cabinet a
pair of laterally spaced control circuitry compartments mounted on
opposite ends of said storage compartment and having front wall
members thereon, said circuitry and compartments being adjacent and
above the respective said paraffin containers and said control
means having manually positionable controls mounted on said front
wall members of said control circuitry compartments.
8. In a system as claimed in claim 7 wherein said cabinet,
including said paraffin and solution containers, said chambers,
pump, valves, and said control circuitry compartments, is assembled
and movable as an integral table top mounted processing unit.
9. In a system as claimed in claim 1 wherein said control means
includes circuitry connected to cycle the application of vacuum and
pressure conditions in said chamber.
10. In a system as claimed in claim 2 wherein said piping means is
connected to said chamber at an upper sidewall position proximate
said chamber cover, said second and sixth valve means are
positioned adjacent said paraffin containers proximate the bottom
walls thereof and immediately adjacent said chamber, said third
valve means is positioned externally of and in close proximity to
the bottom wall of said chamber and including means for
electrically heating said third valve means, said respective valve
positions enabling relatively direct short paths to be established
between the lower interior portion of said chamber and the
respective valves.
11. A system as claimed in claim 1 wherein said control means
include adjustable timing means enabling said predetermined time of
retention to be changed both with respect to all as well as
selected ones of said container melted paraffins and solutions.
12. A system as claimed in claim 1 having fan exhaust and fume
collection means adapted to allow during operation of said system
continuous withdrawl of solution fumes from the area surrounding
said chamber.
13. In a system as claimed in claim 1 wherein said control means is
mounted on said cabinet and said air pump means comprises an
electrically operated air pump mounted in said cabinet and said
interconnected piping means includes an outlet pipe in which said
pressure and vacuum conditions may be selectively produced, said
outlet pipe being connected to said chamber.
14. A closed processing system enabling a plurality of individual
specimens of tissue to be separately contained while being bathed
simultaneously for varying lengths of time in successive selected
tissue solutions including melting paraffin so as to fix, dehydrate
and clear the specimens preparatory to embedding, comprising:
a. a plurality of uniform tissue receptacles each being adapted to
contain and physically isolate a group of tissue specimens having
at least one specimen per group, each receptacle having a body
portion defining an open cavity adapted to receive and retain
specimens and closure means removably received by said body to
enclose said cavity, the material forming said receptacles being
inert to all of said solutions and having for each of said
solutions at least some portion through which each of said
solutions may be transferred;
b. a cabinet adapted for table top mounting and having in an
elevated central and rearward position a plural solution container
storage compartment and on the ends of said storage compartment a
pair of rearwardly disposed control circuitry compartments having
front wall members thereon;
c. a pair of electrically heated, laterally spaced, temperature
controlled paraffin containers mounted in said cabinet below,
forward and proximate said storage compartment, each container
having a movable cover and being adapted for melting and holding
melted paraffin, the temperature control therefor comprising a two
stage control for obtaining two levels of temperature therein;
d. a plurality of closed solution containers mounted in
predetermined order in a storage compartment in said cabinet
proximate said paraffin container, each solution container
containing a particular tissue processing solution and with said
melted paraffin container collectively containing all of the said
tissue solutions in which said specimens are processed;
e. electrically operated air pump means mounted within said cabinet
and having associated remotely electrically controllable first
valve means, interconnected piping means and an outlet pipe
connected thereto, said first valve means being selectively
operable and in various configurations with said piping means to
produce either a pressure or vacuum condition in said outlet
pipe;
f. a processing chamber mounted in said cabinet between and at the
level of said paraffin containers and having end walls immediately
adjacent respective end walls of said melting paraffin containers,
said chamber having a pressure sealable top cover and being adapted
to receive and process therein selected numbers of said receptacles
simultaneously, said chamber being temperature controlled and
electrically heated and being connected proximate said top cover to
said pump outlet pipe thereby enabling the corresponding selected
pressure and vacuum conditions in said outlet pipe to be produced
in said chamber;
g. second and third remotely electrically controllable valve means
mounted in said cabinet proximate the bottom and respective end
walls of said chamber each having on one side a minimal length
fluid connection to said chamber and on the other side a minimal
length fluid connection to a said paraffin container, both said
fluid connections being electrically heated to a temperature above
the paraffin melting point enabling the respective paraffin
contents thereof to be exchanged directly and under remote control
through connection heated paths of minimal distance between the
chamber and the respective said paraffin containers;
h. a fourth remotely electrically controllable valve means having
means for being electrically heated and temperature controlled and
being mounted in said cabinet proximate the bottom wall of said
chamber and having on one side a minimal length fluid connection to
said chamber and on the other side a port for transfer of solutions
therethrough;
i. fifth remotely electrically controllable solution rotary
transfer valve means positioned in said cabinet between said
processing chamber and said storage compartment, said fifth valve
means being connected on one side to said fourth valve transfer
port and on the other side having separate connections to each of
said solution containers and being remotely electrically
controllable for enabling each solution container connection on the
one side of the fifth valve means to be selectively and
independently connected to said transfer port for a predetermined
time while all other solution container connections are isolated
therefrom and at other times to isolate all of said solution
container connections from said transfer port;
j. an electrical power source;
k. remotely operable electrical control means mounted in said
circuitry compartments and having manually positionable controls
mounted on said front wall members, said control means being
connected to said source and being adapted for remotely powering
and electrically operating each of said valve means, said pump
means and said paraffin container temperature controls in a
predetermined time sequence program whereby with a selected number
of said receptacles installed in said chamber and said cover sealed
on said chamber, said solutions and said paraffin are successively,
selectively and independently drawn from said solution and paraffin
containers, measured by timing the withdrawal and admitted to said
chamber under a vacuum condition in a predetermined volume,
retained for predetermined times at a predetermined pressure at the
end of each processing step being forced back to a respective said
solution and paraffin container by pressure from said pump means in
a corresponding processing sequence such that selected of said
solutions and said melted paraffin are separately and independently
exchanged with each said group of specimens while maintaining said
system closed and each said group physically isolated; and
l. electrically operated fan exhaust and fume collection means
mounted proximate said chamber and providing continuous withdrawal
of solution fumes from the area surrounding said chamber.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to tissue processing and more specifically
to processing of tissue for light microscopy examination.
2. Description of the Prior Art
The processing of tissue for both electron and light microscopy
examination has been the subject of step-by-step improvement.
Automatic processing of tissue for electron microscopy tissue
processing has been achieved as exemplified in applicant's U.S.
Pat. Nos. 3,526,203 and 3,771,490.
Automated apparatus for processing tissue for light microscopy
examination has been achieved as exemplified in the so-called
"Technicon" tissue processor; however, there has been no successful
completely automatic system which would allow light microscopy
tissues to be processed under a completely automatic sequence and
in an entirely closed system and without requiring substantial
movement of the specimens. The availability of a closed system is
of critical importance in view of recently published Federal
regulations governing handling of hazardous vapors and fumes.
Representative prior art includes U.S. Pat. Nos. 3,227,130;
2,959,151; 2,386,079; 2,341,198; 2,157,875; 2,959,151; 3,400,726;
2,681,298; and 2,684,925.
A review of the prior art further reveals that treating fluids in
light microscopy processors are normally required to be
recirculated. The processing fluids may be manually returned to
their respective containers after use. Processing takes place in
open or loosely covered chambers which are not suitable for holding
pressure or vacuum conditions. Many of the prior art light
microscopy processors, e.g., the so-called Technicon tissue
processor, also depend upon substantial movement and dipping
motions of the tissue specimens into open containers. Any motion of
the specimens during processing, of course, tends to damage the
specimens if carried to excess.
The prior art has also dealt with the problem of heating paraffin
fluids in containers, flow lines, valves, and the like. However, no
prior art light microscopy processor, so far as is known, has
handled this problem successfully in a closed, effectively sealed
system, or with means enabling the paraffin fluid to be reused. A
fluid flow stainer useful only for staining has been marketed by
Lipshaw Manufacturing Company of Detroit, Mich. This apparatus
recirculates staining fluids with a pressure-vacuum system applied
to the staining fluid containers but it is not useful for
processing tissue, does not provide a pressure vessel type chamber,
and cannot handle paraffin.
In summary, the prior art in its present state does not embody a
practical, reliable and automatic type of processor useful
primarily for processing, including use of melted paraffin, but
adapted to staining light microscopy tissue specimens with a
minimum amount of handling of the tissue specimens, with maximum
economy of the treating fluids, and in a closed system which
substantially eliminates dangers from hazardous treating fluid
fumes.
SUMMARY OF THE INVENTION
The apparatus of the invention provides a plurality of containers
of treating fluids, including paraffin, which are drawn to a sealed
processing chamber by vacuum and returned by pressure which is
applied to the chamber. The tissue specimens are confined in the
processing chamber under sealed cover and remain stationary during
processing. Fixation, processing, and clearing solutions are
directed to the processing chamber in a programmed sequence. The
paraffin containers are arranged in immediate proximity to the
processing chamber which substantially reduces the heating problem
and the paraffin in the second, less contaminated, paraffin
container can, at any time, be pumped to the first container, the
first container paraffin pumped to waste and the second container
paraffin replaced in order to minimize paraffin consumption. The
apparatus is unified in a table mounted cabinet.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the invention processing apparatus
embodied in a cabinet for table top support.
FIG. 2 is a somewhat schematic diagram of the invention showing
particularly a preferred fluid flow configuration based on use of
vacuum and pressure applied to a sealed processing chamber.
FIG. 3 is a partial side view showing the processing chamber
coupled to one of the processing solution containers through a
rotary valve mechanism by appropriate fluid lines in accordance
with the invention, other containers being similarly coupled.
FIG. 4 is a side view to illustrate the shape of processing
solution container found useful for the substantially sealed,
fumeless operation of the invention.
FIG. 5 is a perspective view of a tissue processing and embedding
receptacle used in the present invention.
FIG. 6 is a side cross-sectional view of the invention processing
chamber showing a processing receptacle basket in partial cutaway
view revealing installed tissue processing receptacles.
FIG. 7 is a rear cutaway view of the invention processing chamber
and liquid paraffin containers.
FIG. 8 is a front view of the left side control panel used in the
invention.
FIG. 9 is a front view of the right side invention control
panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In reference to the drawings, a suitable perforated tissue
receptacle 25 for holding the tissue specimens to be processed is
generally shown in FIG. 5 and is known in the art as a TIMS tissue
receptacle. For a more detailed description of TIMS tissue
receptacles used in paraffin embedding histological tissue
sections, reference is made to U.S. Pat. No. 3,411,185 issued on
Nov. 19, 1968, and entitled "Composite Histologic Tissue
Receptacle." A typical receptacle has a removable cover and may
contain one or more tissue samples in the receptacle body cavity to
be fixed, dehydrated, cleared, and paraffin embedded prior to being
thin sectioned on a rotary microtome. Fluids pass through
perforations in the receptacle which is made of materials inert to
the fluids.
As previously mentioned, the light microscopy tissue processor of
the invention is directed to a closed system which allows a
plurality of perforated tissue receptacles 25 to be processed
simultaneously in a sealed chamber according to a scheduled time
sequence, through various selected processing solutions among which
are fixatives, dehydrants, clearing solutions and liquid paraffin.
The particular solutions used and the particular time sequence for
each may vary according to different programs. Also, staining
solutions may be programmed for exchange between the chamber and
the containers when holding staining fluids.
Referring now to FIG. 1, an automatic light microscopy tissue
processor 10 according to a preferred embodiment includes a cabinet
adapted for table top support; a pair of laterally spaced, upper
rearward control compartments 11, 16; a lower, centrally and
forwardly located tissue processing chamber 12; a pair of lower,
laterally and forwardly spaced heated liquid paraffin containers
13, 14; a plurality of solution containers 15 in an upper central
rearwardly compartment for holding the selectively communicated
fluids for processing chamber 12; timing controls 17; and
appropriate container signal lights 18.
Processing chamber 12 remains stationary and includes a tiltable
lid 21 having a window 22. Lid 21 has a hinge 26 and is secured to
processing chamber 12 in a substantially air tight, sealed relation
by appropriate latches 28 and a rim 27 and gaskets 29 (indicated in
FIG. 6). Processing chamber 12 is adapted to recieve a plurality of
tissue processing receptacles 25, best shown in FIG. 5, and more
fully described in the mentioned U.S. Pat. No. 3,411,185. As best
illustrated in FIG. 6, a basket structure 30 having perforated
sidewalls 32 receives said receptacles and supports a plurality of
such tissue receptacles 25 within processing chamber 12. Also shown
in FIG. 6, is an appropriate pressure and vacuum inlet coupling 34
as well as fluid line coupling 35 which communicate with the
interior of said processing chamber 12. A suitable rectangular
perforate plate 24 provides weight sufficient to overcome the
buoyancy of the tissue receptacles 25 and keeps them submerged
during processing.
Referring now to FIG. 2, solution containers 15 are connected to
processing chamber 12 by individual conduits 38 which communicate
with a rotary valve structure 39 and then through a common conduit
33 to electrically operated valve 42 and from there directly into
processing chamber 12. When solutions are returned to their
containers, they simply retrace the supply route in reverse. Rotary
valves as such are known and while a single rotary valve as
illustrated has many advantages, a solenoid valve at each container
could be employed to achieve selection and controlled fluid flow in
conjunction with the unique paraffin related apparatus later
described.
Water base solutions, such as Zenker's, formalin and water, are
effectively kept separated from oil base solutions such as Xylene,
the combination of which causes formation of an emulsion. Typically
then, for the ten numbered solutions shown, the invention
contemplates that solution one will be fixative, e.g., Zenker's or
formalin; solutions two through six will comprise various
percentages of alcohol for dehydrating; and solutions seven and
eight are Xylene for clearing. Further solutions such as Xylene and
alcohol will be contained in containers nine and ten for purposes
of cleaning processing chamber 12 following a completed processing
sequence and withdrawal of processed tissue specimens from chamber
12.
The following table shows a series of processing and cleaning
solutions which might typically be used according to the
invention:
Container No. Solution ______________________________________ 1
Zenker's (or formalin) 2 70% Alcohol 3 80% Alcohol 4 95% Alcohol
Processing 5 Absolute Alcohol Cycle 6 Absolute Alcohol 7 Xylene 8
Xylene Paraffin I Paraffin II 9 Xylene Cleaning 10 Absolute Alcohol
Cycle Additional water rinses manually done, if desired.
______________________________________
Referring now to FIG. 3, a typical processing solution container 15
of a commercially available shape as in FIG. 4, conduit 38, rotary
valve 39 made up of rotatable plate 41 and fixed plate 43, common
conduit 33, valve 42 and processing chamber 12 are shown in
operative assembly. A suitable swivel connection 40 allows the
movable rotary valve plate 41 of rotary valve 39 to rotate. While
FIG. 3 only illustrates the fluid path for only one solution
container 15, it should be clear from FIG. 2 that there are in fact
ten solution containers, all of which feed into rotary valve 39 and
then into common conduit 33. Container 15 of FIG. 3 is shown having
a fitting 54 which will facilitate rapid changing of solution
containers. A tube 58 communicates with the bottom of container 15
to drain the entire contents, if desired, during processing.
As previously mentioned, the invention processor is adapted to be
operated so that all solution admission, solution retention and
solution drainage takes place in automatic or alternately, manual
timed sequence and in a substantially closed system. Selective
application of air pressure and partial vacuum to the sealed
processing chamber 12 in conjunction with operation of valve 42,
etc., enables rapid transfer of processing solutions from
containers 15 to chamber 12 and back to containers 15 again.
With specific reference again to FIG. 2 a combined vacuum and
pressure system 60 is shown in dashed lines and comprises a
pressure pump 61 having means for providing pressure as well as
partial vacuum as indicated and remotely operable valve means 64,
65, for selecting whether vacuum or pressure is applied to an air
line 70 communicating with processing chamber 12.
Referring again to FIG. 3, solution admission and drainage from
chamber 12 and fluid measurement is controlled by selective
application of pressure and partial vacuum to the chamber 12 via
the air line 70 in conjunction with timed operation of the remotely
operable rotary valve 39 and remotely operable valve 42. Air line
70 preferably connects to the interior of chamber 12 at a
relatively high location near the cover as illustrated which avoids
entry of the solutions into chamber 12. By creating a timed partial
vacuum in chamber 12, a selected fluid is drawn into the chamber,
and by pressurizing chamber 12 the fluid is expelled from the
chamber. Reference will next be made to FIG. 2 for a discussion of
one pressure, vacuum and rotary valve arrangement useful in the
invention, and then to FIGS. 2 and 7 for a description of liquid
paraffin flow to and from chamber 12 according to the invention.
Since rotary valves are known, no detailed description of valve 39
is deemed necessary.
Referring again to FIG. 2, in a "pump in" cycle fluid flow to
processing chamber 12 from any given solution container 15 or
paraffin containers 13 or 14 is effected by creating a timed,
partial vaccum in the sealed processing chamber 12. In the diagram
shown, this is accomplished by actuating valve 64 to enable air to
flow between F and B, by energizing pump 61, and by actuating valve
65 to enable air to flow between D and E on a timed schedule.
Simultaneous with the application of a partial vacuum to chamber
12, rotary valve 39 rotates to provide a path through valve 39 for
the desired solution to flow through valve 39, into conduit 33,
through valve 42 and on into processing chamber 12. As an example,
to move a measured quantity of solution number one to chamber 12,
rotary valve 39 is energized and plate 41 is rotated until the line
38 from container number one lines up with the conduit 33 opening
and valve 42 is opened on a timed schedule. Air drawn from chamber
12 during such vacuum cycle is expelled to atmosphere by means of a
filtered exhaust 69 which is located so as to have its fumes
withdrawn as illustrated in FIG. 2. Alternatively, in a "pump out"
cycle to effect fluid flow back to a selected solution container
15, chamber 12 is pressurized above atmosphere by actuating valve
64 to permit air to flow between A and B, and by actuating valve 65
to permit air to flow between D and F. Air is taken into pump 61 by
means of an intake opening at A. Suitably, valve 42 and rotary
valve 39 assume the same open position as on the vacuum or pump in
cycle to enable fluid to flow back into the appropriate container
15. The fluid and air line valves normally remain closed while a
pump in or pump out cycle is not in progress with the exception of
the air line valves used during vacuum and pressurized agitation
later described. Valve 42 is located immediately adjacent the rear
wall and is closely coupled to chamber 12 and is positioned
proximate the bottom wall of chamber 12. This position facilitates
entry and drainage of fluids. Also, by keeping valve 42 closed
during use of paraffin, there is a minimum opportunity for the
paraffin to block valve 42.
Referring again to FIG. 3, the previously referred to solution
containers 15 (with operating numbers 1 through 10) have respective
caps 55 for refilling the containers. Suitable air vents 56,
indicated by dashed lines, are provided in each cap 55, but are
preferably kept extremely small so as to limit any admission of
moisture. Caps 55 may also be provided with dessicant material 57
to keep certain solutions e.g., absolute alcohol substantially free
from moisture. As illustrated in FIGS. 1 and 2, fluid vapors vented
to atmosphere during normal operation of processor 10 are collected
by a fume manifold 74 serving as a top portion of housing 11 and
are exhausted by an appropriate fan 74a. A suitable trap line 70
filters fumes, et cetera.
Referring next to FIG. 7, liquid paraffin is stored in two heated
and temperature controlled, laterally spaced containers 13 and 14
residing immediately adjacent and on either side of processing
chamber 12. Transport of liquid paraffin from either container 13
or 14 to chamber 12 is preferably accomplished by use of valves 75,
75' which are illustrated in submersed positions immediately
adjacent and near the bottom wall of chamber 12. Respective conduit
means 62, 63 communicate valves 75, 75' with chamber 12 as shown.
This arrangement enables the heating elements 77, 77a (shown
schematically in FIG. 2) which are integral with paraffin container
13, 14 respectively to maintain the correct temperature in the
liquid paraffin as well as in the respective valves 75, 75' and the
conduits 62, 63. Thermostats 76, 76a and thermal fuses 76b , 76c
maintain the desired temperature and prevent overheating. Valves
75, 75' may also be located externally of the respective paraffin
containers but should have close, i.e., minimal distance couplings
both to the paraffin containers 13, 14 and to chamber 12 and should
be near their bottom walls.
It should be noted that the provision for two separate paraffin
stages as embodied by the invention enables substantially complete
paraffin impregnation of tissue specimens prior to paraffin
embedding. While one paraffin stage could be used, use of two
paraffin stages is generally consistent with current tissue
processing technique, although variation on the exact number of
paraffin steps may occur between different histological
technicians. Paraffin containers 13 and 14 may be formed
substantially integral with processing chamber 12 separated only by
common partitions 66. A lid 23 on each paraffin container 13 and 14
is hinged and may be periodically opened to replenish the supply of
paraffin, while respective manual drain means 81 may be used to
drain the used, impure paraffin. Paraffin containers 13 and 14 are
not required to be pressure sealed but should preferably be closed
to atmosphere contamination.
As will be described later, control means are provided in the
invention enabling transport of a body of liquid paraffin from one
paraffin container to the opposite enabling impure paraffin used,
say, in the next sequential step following the last step of Xylene
(solution 8 of FIG. 2) to be periodically drained and replaced with
less impure paraffin previously used in the final processing step.
This enables a substantially pure body of paraffin to be maintained
for the last processing step, but makes use, through an automatic
"paraffin exchange" step, of slightly impure paraffin for the next
to the last processing step. Such exchange of paraffin is
contemplated every sixth processing sequence.
Prior to discussing the programming sequence reference is again
made to schematic diagram of FIG. 2 wherein note should be taken of
the use of a dual heating element to heat processing chamber 12. A
first heating element 84, located in the sidewall of processing
chamber 12 (see FIG. 6), is adapted to gradually provide heat to
said chamber 12 from the first processing step until the first
paraffin step (after sequential solution 8 of FIG. 2) and is set by
thermostat 85 and by thermal fuse 86 to approach but not to exceed
42.degree.C. Slight heating of chamber 12 throughout the early
tissue processing sequence, e.g., fixative, dehydrating, and
clearing steps enables better solution penetration into the tissue
and also provides a pre-heated container prior to entry of melted
paraffin. Temperature must be restricted during the steps of such
volatile solutions as alcohol and Xylene. Once the first paraffin
step is reached, however, second heating element 89, located in the
base of processing chamber 12 (see FIG. 6) is adapted to be
energized raising the temperature within chamber 12 to 62.degree.C.
It should be noted that the lag time for this necessary temperature
rise need only be very short, e.g., 15 seconds, since chamber 12
approximates 62.degree.C immediately prior to the first paraffin
step. Thermal fuse 82 and thermostat 83 prevent overheating of
chamber 12 during paraffin steps. While heaters 84 and 89 are shown
in a preferred location, alternate locations might be chosen to
achieve the desired result of even temperature throughout
processing chamber 12. As seen in FIGS. 3 and 6, a third heating
element 91 is located adjacent the rear wall of chamber 12. Element
91 effectively maintains a suitable operating temperature on valve
42 and minimizes clogging by any paraffin which happens to enter
the valve port adjacent chamber 12. Thermal fuse 92 and thermostat
93 prevent overheating of chamber 12. The overall heating is also
designed to maintain all paraffin carrying pipes at an above
melting temperature.
As heretofore described, vacuum and pressure conditions are
selectively applied to the sealed processing chamber 12 and are
effectively used to transport the various processing and cleaning
solutions of the invention tissue processor to and from the
processing chamber. An advantageous feature of the invention
arrangement resides in its capacity to use remotely and
electrically operated valves, heaters and the electrically operated
air pump 61. Another advantage is the capacity to apply such vacuum
or alternating vacuum and pressure to said processing chamber while
a selected solution is in said chamber, to enhance solution
penetration into the tissue being processed. In addition, vacuum or
alternating vacuum and pressure applied to solutions in chamber 12
may result in improved penetration of tissue in the receptacles
installed in the chamber due to trapped air bubbles being
freed.
Referring again to FIG. 2, vacuum or alternating vacuum and
pressure applied to chamber 12 during processing of given solutions
(including paraffin) hereinafter referred to as an "agitation
cycle" is preferably conducted at periodic intervals, e.g., every
10 minutes while each of selected processing solutions is in
chamber 12. The term agitation is used in a loose sense to mean
increasing tissue penetration by vacuum or pressure, releasing air
bubbles, and the like. It has previously been mentioned that air
valves 64 and 65 and fluid valves 42 and 39 remain closed while a
given solution is not being pumped to or from chamber 12. To create
a partial vacuum in chamber 12 for purposes of agitation valves 64
and 65 are set to the previously described vacuum cycle positions,
and pump 61 is energized for a predetermined period of time set by
an agitator timer 104 (not shown on control panel). A vacuum of -22
p.p.s.i. may be exerted, for example. The invention also
contemplates the use of a partial vacuum periodically during given
solution steps and a pressure during other solution steps. Pressure
may be applied by moving valves 64 and 65 to the respective
pressure cycle positions and energizing the electrically operated
air pump 61. It is apparent that suitable programming of
alternating pressure and vacuum agitation cycles or simply of
intermittent vacuum cycles may be readily accomplished by stepping
switches or logic circuitry well known to those skilled in the
art.
The program logic and stepping control 100 employed by the present
invention may comprise a suitable rotary stepping switch having a
clock drive, or preferably solid state logic circuitry. In any
case, the logic or stepping mechanism involved is deemed well
within the related art so as to not require detailed elaboration
herein. The general type of circuitry required has been illustrated
in FIG. 2 and is of the type generally described, for example, in
prior U.S. Pat. No. 3,771,490. In order to illustrate typical
operations of the described processing apparatus, however, the
description will now briefly describe a series of controls and
their preferred functions used by the invention.
Referring now to FIGS. 2, 8 and 9, an on-off switch 102 controls
power to the processor program and stepping control 100. The power
is preferably continuously supplied to paraffin bath heating
elements 77 and 77a via thermostats 76, 76a and thermal fuses 76b,
76c to maintain the paraffin contained in baths 13, 14 above
melting point even while processor 10 is idle. Thus, the paraffin
temperature is preferably unaffected by operation of on-off switch
102. Switch 102 preferably contains a suitable indicator lamp 107
to indicate to the operator that the processor is energized.
Selective manual or automatic operation is provided by a mode
selector switch 111. For manual operation switch 109 is employed
and for automatic operation switch 110 is employed. Manual control
of sequential, i.e., step-by-step, processing steps is provided by
push button switch 112 and which causes illumination of solution
signal lights 18 (see also FIG. 1). Manual solution pumping in or
pumping out cycles are controlled by switches 114 and 115,
respectively, which govern vacuum and pressure cycles of the vacuum
pressure system 60. The signal lights 18 are preferably arranged to
illuminate to half intensity indicating which step the processor
has reached, and to full intensity whenever the respective solution
is being pumped to or from chamber 12. A level control switch 117
provides a choice between high, medium, and low solution levels in
chamber 12 by controlling the length of time which pump 61 operates
during a given solution pump-in or pump-out. Thus, processor 10 is
adapted to handle either relatively large or small quantities of
processing receptacles.
For determining the length of time the tissue samples are exposed
to each processing solution, a pair of manually set timers 120,
121, including hour and minute settings, are provided. Step
duration selector switches 125 (see FIGS. 1 and 2) are located
above each processing solution container. Similar step duration
selector switches 125' on left control panel 11 provide a similar
function for the paraffin containers 13, 14. Switches 125, 125'
enable selection between times 120, 121 or alternately to zero time
which causes the particular step to be skipped or to unlimited time
which causes the particular solution to be pumped in during
automatic sequence but not pumped out. A time display 130 informs
the operator of elapsed time for each solution and automatically
resets when the next solution is admitted to chamber 12. A manual
time display reset 131 is provided. A hold button 137 on control
panel 16 is provided and suitably connected to temporarily
interrupt the timing sequence in case of emergency, et cetera.
Under an automatic mode of operation of the processor, solution
pump-in, pump-out and stepping to the next solution step takes
place in the appropriate preselected time sequence, throughout the
designated processing solution numbers 1 through 10 and including
the two paraffin steps hereinbefore described. The last paraffin
step is preferably adapted to stay in chamber 12 until the operator
removes the processed tissue, reseals chamber 12 and manually
begins a clean out cycle by operating mode selector switch 111.
Pump-out switch 115 is depressed until all of the paraffin in
chamber 12 is pumped back into paraffin bath number 2. The clean
out operation is started by depressing manual step button 112 which
effectively moves the system up to the next solution. Pump-in
button 114 is depressed and held until a desired amount of solution
number 9, e.g., Xylene, is pumped into chamber 12. Chamber 12 is
manually cleaned with Xylene solution and the excess solution is
vacuum removed in the clean out operation. Next, step button 112 is
depressed which moves the system up to solution number 10, e.g.,
absolute alcohol. Button 114 is depressed and begins pumping
solution 10 into chamber 12. Button 114 is held until a desired
level of solution 10 is pumped into chamber 12 and is then released
stopping the pumping. Chamber 12 is further cleaned manually. Once
chamber 12 is cleaned, mode selector 111 can now be set to
automatic and chamber 12 refilled with TIMS receptacles for
processing another batch of tissue specimens placed therein.
It is desirable to be able to remove the paraffin in paraffin
chamber 13 since it becomes contaminated after it is used several
times. Once removed, the less used paraffin in container 14 can be
pumped to chamber 13 by using vacuum to draw the paraffin into
chamber 12 and then pressure to force it into container 13. The
paraffin in chamber 13 is drained out with the aid of manual drain
81 of chamber 13 and paraffin chamber 14 after being emptied is
then charged with new paraffin.
In most processing applications, it is desirable to hold the tissue
in the receptacles in the No. 1 solution (e.g., Zenker's or
formalin) for several hours prior to initiating an automatic timed
solution processing sequence. For such purpose, a long delay timer
134 may be employed so that the first solution may be admitted
manually and the remainder of the particular program on an
automatic basis after some predetermined time delay, such as in the
order of 4 hours for short term runs or in the order of 72 hours
for weekend runs. Suitably, an additional switch applies the delay
timer 134 to that solution step.
While a wide choice of materials are available with which to
construct the various components of the apparatus of the invention
it will, of course, be apparent that some of the solutions,
particularly Xylene, are of a toxic and corrosive nature with
respect to certain materials. The choice of material employed in
constructing the processing chamber, solution containers, conduits,
valves, and the like, should keep these factors in mind.
While the invention has been described primarily in terms of a
light microscopy tissue processing application, it will be apparent
that de-energization of the heating paraffin steps, elimination of
the cleaing steps, and addition of a slide rack to the processing
chamber, will render the processor highly suitable for use as an
automatic mounted slide staining apparatus.
In summarizing the advantages of the present invention tissue
processing apparatus, it will be noted that a substantially closed
fumeless and simplified system has been provided for fixing,
dehydrating, clearing, and paraffin infusing light microscopy sized
tissue in a relatively large quantity. Those skilled in the art
will particularly recognize the advantages of maintaining tissue in
a stationary, sealed chamber during processing. In addition, the
selective application of partial vacuum and pressure to the
processing chamber has the two-fold effect of providing a mechanism
for fluid transfer as well as a means for enhancing fluid
penetration into the tissue.
The mounting of the air pump 61 and its associated piping and
valves in the cabinet provides a unitary and self-contained
processing apparatus with obvious advantages. However, it is
recognized that the source of vacuum and pressure conditions could
be obtained by use of separate external laboratory vacuum and
pressure supplies fitted with electrical valves and leading direct
to processing chamber 12. Also the controls could be mounted in a
separate cabinet. However, this also would tend to detract from the
many advantages of unifying all the necessary processing and
control apparatus in a common table top mounted cabinet. Close
valve coupling between the processing chamber and the one or more
heated paraffin containers is most desireable to provide heated
paths of minimal length to minimize the amount of heat required to
keep the paraffin in those fluid paths which necessarily carry the
paraffin back and forth to the processing chamber. The paraffin
containers should preferably be immediately adjacent the processing
chamber and all fluid connections for the paraffin should be of
minimal length for the reasons stated. Some separation can be
tolerated however, provided any interconnecting paraffin carrying
pipes are sufficiently heated and such heat is insulated as
required to prevent heating those solutions which should preferably
not be heated.
* * * * *