U.S. patent application number 09/828829 was filed with the patent office on 2002-10-10 for punch-changing tissue array instrument.
Invention is credited to Leighton, Stephen B..
Application Number | 20020146813 09/828829 |
Document ID | / |
Family ID | 25252845 |
Filed Date | 2002-10-10 |
United States Patent
Application |
20020146813 |
Kind Code |
A1 |
Leighton, Stephen B. |
October 10, 2002 |
PUNCH-CHANGING TISSUE ARRAY INSTRUMENT
Abstract
Arrays of biological tissue can be created by removing cores
from regions of interest in a series of donor blocks of embedded
tissues. The cores removed are placed in a regular array in a
recipient block. This is typically done with two different punches,
one for obtaining the cores of interest and the other for creating
the receiving holes in the recipient block. The present invention
comprises such a system including a single z axis, with a mechanism
for automatically changing two or more punches in and out of a
holder on the z axis.
Inventors: |
Leighton, Stephen B.;
(Silver Spring, MD) |
Correspondence
Address: |
Stephan A. Pendorf
Pendorf & Cutliff
P.O. Box 20445
Tampa
FL
33622-0445
US
|
Family ID: |
25252845 |
Appl. No.: |
09/828829 |
Filed: |
April 9, 2001 |
Current U.S.
Class: |
435/286.3 ;
435/287.3; 435/307.1; 435/309.1 |
Current CPC
Class: |
G01N 2001/288 20130101;
G01N 1/08 20130101; G01N 1/36 20130101; G01N 35/0099 20130101; G01N
1/286 20130101; G01N 2001/368 20130101 |
Class at
Publication: |
435/286.3 ;
435/287.3; 435/307.1; 435/309.1 |
International
Class: |
C12M 001/26 |
Claims
I claim:
1. An instrument for constructing arrays of tissue in a recipient
block, the instrument comprising: first and second punch units,
each punch unit comprising a punch including a punch hub and a
stylet including a stylet hub, means for holding at least one donor
block, means for holding at least one recipient block, gripper
means for releasably precisely holding one of said punches at a
time, means associated with said gripper for moving said stylet hub
relative to said punch hub, means for precisely moving and
positioning said punch hub relative to at least one of said donor
and recipient block holders, wherein said gripper means is adapted
for receiving, moving, and releasing said punches individually.
2. An instrument as in claim 1, wherein said gripper is provided
with means for movement in the z axis.
3. An instrument as in claim 1, wherein said donor and recipient
block holders are provided with means for movement in the x and y
axes for selectively repositioning said recipient block holder and
said donor block holder relative to said gripper.
4. An instrument as in claim 1, wherein said donor block and
recipient block holders are provided on a turntable rotatable about
a z axis.
5. An instrument as in claim 1, wherein one or more of the motions
are under computer or manual control via powered drives.
6. An instrument as in claim 1, wherein the donor block holder and
the recipient block holder are provided on different platforms.
7. The instrument as in claim 6, wherein one of said the donor
block holding platform and recipient block holding platform is
moveable in at least one of an x and y axis, and wherein the other
of said platforms is formed by a turntable rotatable about the z
axis.
8. The instrument as in claim 1, wherein the donor block holder and
the recipient block holder are provided on the same platform.
9. An instrument as in claim 1, further comprising an amount of
compliant wadding material provided inside the punch at the tip of
the stylet.
10. An instrument as in claim 1, wherein said compliant wadding
material is an elastomer.
11. An instrument as in claim 1, wherein said stylets are driven by
an actuator which can exert controlled forces.
12. An instrument as in claim 1, wherein the stroke length of said
stylets can be controlled via said stylet actuators.
13. An instrument as in claim 12, wherein the stylet actuators are
controlled for stroke length via a computer.
14. An instrument as in claim 1, further comprising a magazine
containing blocks, and operatively associated with means for
providing blocks to said instrument and/or receiving blocks from
said instrument.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Arrays of biological tissue can be created by removing cores
from regions of interest in a series of donor blocks of embedded
tissues. The cores removed are placed in a regular array in a
recipient block. This is typically done with two different punches,
one for obtaining the cores of interest and the other for creating
the receiving holes in the recipient block. The present invention
concerns a simplified and economical system and device for creating
tissue arrays.
[0003] 2. Description of the Related Art
[0004] Biological tissue arrays consist of regular arrays of cores
of embedded biological tissue arranged in a sectionable block
typically made of the same embedding material (e.g., paraffin) used
originally for the tissue in the cores. The new blocks may be
sectioned by traditional means (microtomes etc.) to create multiple
nearly identical sections each containing dozens, hundreds or even
over a thousand different tissue types. These sections may be used
for histochemical and other assays. Any test performed on any one
of these sections is effectively performed on hundreds of samples
at once. The result is a tremendous saving in effort and time and
some increase in the availability and precision of control
samples.
[0005] Tissue arrays have been constructed entirely manually
(Battifora, H., "The multitumor (sausage) tissue block: novel
method for immunohistochemical antibody testing", Laboratory
Investigation Vol. 55, pp. 244-248, 1986) and with the assistance
of mechanical mechanisms (Kononen et al., "Tissue microarrrays for
high-throughput molecular profiling of tumor specimens", Nature
Medicine Vol. 4, Number 7, pp. 844-847, July 1998) for a variety of
biological applications. A manual instrument has also been
described in Leighton, U.S. Pat. No. 6,103,518 "Instrument for
constructing tissue arrays". Semiautomatic systems have also been
proposed (Leighton U.S. patent application Ser. No. 09/811,963
entitled "Double Z-Drive Tissue Array Instrument", incorporated
herein by reference). The manual methods have largely been
superceded by those aided by instruments due to the speed,
precision and increased density of the latter. In these devices,
two hollow needle-like punches are used, one slightly smaller
(recipient punch) than the other (donor punch) to create a hole in
a recipient block, typically of paraffin or other embedding medium.
The larger or donor punch is used to obtain a core sample from a
donor block of embedded biological tissue of interest.
[0006] The punches are sized such that the sample obtained just
fits in the hole created in the recipient block. Thus the sample is
a snug fit in the recipient block and a precise array can be
created.
[0007] The recipient block is held in an appropriate fixture during
the entire process--although it may be removed and alternatingly
replaced with one or more other recipient blocks to create more
than one array from one set of donor blocks. Micrometer drives or
other precision linear positioning means position the punches with
respect to the recipient block or the recipient block with respect
to the punches. It is clearly desirable that the donor punch reach
exactly the same position that the recipient punch reaches on the
recipient block for a given setting of the micrometer drives. If it
does not, the retrieved sample will not pass smoothly into the hole
just created for it, but instead will be damaged or lost. It is
further desirable that this motion be created reliably and
inexpensively.
[0008] In Kononen et al it is taught to use slides and drive
mechanisms to first move the recipient punch into a central
position and, alternately, the donor punch. This mechanism is
cumbersome, expensive, slow and prone to misalignment errors. The
use of slides at an intermediate angle such as 45 degrees, as
taught by Kononen et al is particularly problematic, as small
errors in height positioning can lead to corresponding errors in
lateral position and vice versa.
[0009] Leighton U.S. Pat. No. 6,103,518 entitled "Instrument for
constructing tissue arrays") teaches a turret or other means
allowing two punches to share a single z axis slide or drive. This
mechanism is appropriate for a simple, manually operated
instrument, but may be awkward for an automated instrument in which
all motions are driven by powered actuators (pneumatic, electric
etc.). Special mechanisms must be machined and assembled, and
standard components are not available.
[0010] While the above systems are operable, there remains a need
for a system which can be fully automated yet has fewer robotic
parts than the above-described systems.
SUMMARY OF THE INVENTION
[0011] It is the purpose of the present invention to allow a
standard laboratory robot to be adapted to make tissue arrays. In
addition, it is the purpose of the present invention to provide a
means for constructing a robust automated instrument.
[0012] After extensive investigation, the present inventor realized
that in all of the prior art it has been the conventional thinking
that the two different punches should be held permanently in some
part of the mechanism or drives. Apparently, it may have been
thought that permanently holding the punches in respective holders
was necessary in order to guarantee accuracy and correct alignment,
or that primary goals of operational simplicity and speed in a
single, dedicated machine blinded those working in this art to the
possibility of using a single set of x-y-z axes and then adding a
mechanism for alternately placing first one and then the others of
two or more punches into position on the working end of one of the
axes.
[0013] The present inventor has now surprisingly discovered that
the duplex robotics of the prior art are not required, and has
developed a simple and precise means of forming tissue arrays by
alternately positioning the two different punches in any tissue
array instrument.
[0014] The invention comprises completely separating the two
punches (donor and recipient), giving each their own stylet (unlike
Kononen et al) and using a single z-drive (unlike the double z
drive disclosed in the Leighton patent application) but not
resorting to a cumbersome turret or slider means (as disclosed e.g.
in Leighton U.S. Pat. No. 6,103,518 "Instrument for constructing
tissue arrays").
[0015] The improvements over the prior art include using changeable
punches that can automatically and alternately be held by a moving
gripper and actuator.
[0016] The x, y and z drives that are present for general
positioning in most laboratory robots can be simply programmed not
only to bring the active punch to the appropriate position with
respect to a donor or recipient block and to do the punching, but
also to bring the punch holder to a magazine or storage area, to
release one punch, and to acquire another.
[0017] The positions of the tips of the two punches can be
periodically measured automatically by sensors mounted on the same
pallet as the donor and recipient blocks. Whenever their positions
may have moved (perhaps due to encountering a more dense block or
irregularity, or perhaps by being disturbed by an operator or
foreign object, or simply being altered by virtue of a new punch
being installed) then the new positions can be measured and the
measurement automatically used to update the offset value. Sensing
the tip positions with a sensor mounted on the block holding pallet
allows a system to be constructed with standard components and to
be robust in the face of environmental challenges and mechanical
drift. The position sensing may be used to overcome any variation
in tip position caused by alternately replacing the punches
automatically.
[0018] Typically, the punches are stored in simple holders attached
to the same substrate that holds the donor and recipient blocks and
a complementary holder or gripping means is attached to a member or
arm that can move in x, y and z with respect to said substrate. (Of
course, there are various combinations of motion that are obvious
to one skilled in the art, such as having the substrate fixed with
respect to the laboratory frame of reference and the arm moving in
x, y and z or the substrate moving in x an y and the arm moving
only in z or the substrate moving in x and the arm moving in y and
z etc. The reference to movement in the z axis should be understood
as relative movement between punch and donor or recipient block.)
The holder or gripping means can be switched between a gripping and
releasing mode by the same computer or controller that is
controlling the rest of the operations of the instrument, or the
gripping and releasing may be entirely mechanical, activated by the
approach and withdrawal motions of the gripper with respect to the
holding location.
[0019] Once the appropriate punch is firmly held in the gripping
means, the motion drive can move the punch to the appropriate
position for punching holes in a recipient block, discharging waste
to a waste receptacle, acquiring tissue from a donor block, or
inserting tissue into a recipient block. A surface sensing device
could either be permanently attached to the moving arm or could be
an alternate tool that can be picked up when needed instead of one
of the punches.
[0020] Since each of the two punches can be picked up and used by
the same axis, only one x, y, z drive system is required. Compare
Kononen et al, where six drives are required, two for moving the
two punches into and out of position, one for moving the punches
into and out of the blocks and two for x, y motions of the blocks.
In Leighton (U.S. Pat. No. 6,103,518 "Instrument for constructing
tissue arrays"), manual operation is contemplated, but were the
system to be automated, four drives would be required, and they
would need to be of two different types, one for toggling the
turret from one position to the other, and another for moving the
turret up and down. This would result in greater costs, as two
different types of drives would be required to be designed and
manufactured for the two different types of motion.
[0021] In the present invention, a standard laboratory robot can be
used, leading to reduced costs and simplicity.
[0022] While two punches are employed in the above discussion for
simplicity, it will be readily understood that it is easily within
the scope of this invention to use more than two punches, each
stored in a similar holder on the substrate, for example to permit
quick changes between different sizes of punches for different
applications. It is also possible to use the punch holder to hold a
tool for moving blocks, a tool for labeling blocks, or other tools
or devices.
[0023] The rest of the system may be similar to that already
described in the prior art. For example, powered or manual
micrometer drives or the like may be used to position the punching
mechanism over the blocks or the blocks under the punching
mechanism. A removable bridge may be used for supporting the donor
blocks over the recipient blocks, or the donor blocks may be
attached to the same pallet that holds the recipient blocks. The
latter arrangement allows the same x and y drives and slides to be
used for both donor and recipient blocks. Alternately, separate x,
y systems could be used for the recipient blocks and the donor
blocks. This is more complicated, but can permit faster operation
for high-throughput systems.
[0024] The foregoing has outlined rather broadly the more pertinent
and important features of the present invention in order that the
detailed description of the invention that follows may be better
understood, and so that the present contribution to the art can be
more fully appreciated. Additional features of the invention will
be described hereinafter, which form the subject of the claims of
the invention. It should be appreciated by those skilled in the art
that the conception and the specific embodiments disclosed may be
readily utilized as a basis for modifying or designing other tissue
arrayers for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent structures do not depart from the spirit and
scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] For a fuller understanding of the nature and objects of the
present invention reference should be made to the following
detailed description taken in conjunction with the accompanying
drawings in which
[0026] FIG. 1 is an isometric semi-schematic drawing of the
punch-changing tissue array instrument.
[0027] FIG. 2 is a detailed view of a clamp-type gripping
mechanism.
[0028] FIG. 3 is a detailed view of an orifice-type gripping
mechanism.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The invention will now be described in greater detail by
reference to the drawings.
[0030] In FIG. 1 there is illustrated a punch-changing tissue array
instrument wherein punch 31 is held by arm 33 and moved vertically
by drive 35. Coaxially inside the punch is stylet 37 moved by drive
41 for the stylet actuator and moved vertically relative to the
punches by actuator 39. A computer 43 controls all of the drives or
actuators. A pallet 44 is moved in the x and y directions by
actuators 47 and 48. The pallet holds recipient blocks 45, donor
blocks 46, a waste receptacle 49 and a sensor 50.
[0031] The sensor allows the computer to find the position of the
punches with respect to the pallet. Other sensors, limit switches,
encoders and feedback elements may be employed but are not shown
for clarity of the illustration, and since their use is well know
in the art.
[0032] FIG. 2 shows a dual clamping mechanism as one possible type
of gripping mechanism. Computer controlled solenoids 70, 73 are
connected to clamping jaws 71, 74 via actuating arms 72, 75. The
upper clamping jaw grips the stylet hub and is connected to the
stylet drive, the lower clamping jaw grips the punch hub and is
connected to the punch drive.
[0033] FIG. 3 shows an alternative dual gripping mechanism. Stylet
gripper 80 has an orifice slightly larger than the stylet hub.
Punch gripper 81 has an orifice slightly larger than the punch
hub.
[0034] Upon activation of hydraulic (e.g., balloon seal, hydraulic
clamping jaws), electromagnetic, or vacuum suction means, the
stylet gripper and punch gripper grip the stylet and punch,
respectively.
[0035] It is preferred that the gripper be provided with a
register, which may be a simple "V" shape, against which the stylet
or punch hub is positioned for precise positioning.
[0036] Obviously, the grippers can be designed and operated
similarly, or the grippers can be of different type.
[0037] Although there are many ways to construct the punch-changing
tissue array instrument, one preferred embodiment will now be
described in greater detail. Two punches, a recipient and donor
punch, are stored, each in a separate holder on a substrate which
also holds the donor and recipient blocks (FIG. 1). Each is
provided with a stylet for pushing wax or tissue out of the
punch.
[0038] Either punch/stylet assembly can be brought under the
gripper of the z-axis (FIG. 2) with the same x, y traverse system
that is used to move the donor and recipient blocks. The z axis is
then used to move the gripper down and grasp the punch that is
required for the next operation. When it is necessary to change to
a different punch, the empty punch holder 60 is brought under the
gripper of the z-axis drive and the z axis drive lowers and
releases the punch that is no longer required. The z axis drive
then lifts the empty gripper, the other punch is brought underneath
the gripper, and the z-axis drive lowers the gripper to acquire the
target punch.
[0039] As a punch is acquired, its stylet is connected to the
stylet drive in the same operation. The stylet of the active punch
may be driven by a simple pneumatic cylinder. The pneumatic
cylinder allows precise positioning of the stylet in either the
fully up or fully down position, and also allows controlled forces
at intermediate positions for tamping the cores, merely by
adjusting the air pressure. It would also be within the scope of
the invention to use an electromechanical actuator (with force
sensor if necessary) instead of the pneumatic cylinder, or to use
pneumatic or hydraulic cylinders for positioning the punch.
[0040] Preferably, electromechanically driven slides position a
pallet in the x and y axes to allow precise positioning of a set of
one or more recipient and donor blocks under the punch. All of the
motions may be under electronic and computer control by any of many
well know means--e.g., limit switches, sensors, position feedback,
stepper and/or servo motors and the like.
[0041] A typical cycle consists of the desired recipient position
being brought under the recipient punch by the x-y drives; the
recipient punch being moved by its z drive to penetrate and remove
a blank core, creating a pocket for later use; the recipient punch
being brought (by the x-y drives) near a waste receptacle (which
may be mounted on the same x-y pallet as the blocks) and the
recipient stylet being moved to discharge the blank core into the
waste receptacle; the recipient punch being returned to its holoder
and the donor punch acquired, the desired position of a donor block
being brought by the x-y drives under the donor punch; the donor
punch being moved by its z drive to penetrate and remove a desired
core of tissue; the previously created pocket in one of the
recipient blocks being brought by the x-y drives under the donor
punch; and finally the donor punch being brought in contact or
nearly in contact with the recipient block by its z drive and then
its stylet being moved to implant the tissue core in the pocket
created in the recipient block. Next, the lateral position is
incremented with drives X and or Y to the next position and the
cycle is repeated.
[0042] It is within the scope of the patent that either the blocks
or the punches can be moved in x, y and z directions relative to
the laboratory frame of reference--only relative motion matters in
this invention.
[0043] Wadding or packing at the end of the stylets
[0044] Wadding or packing may be provided at the end of the stylets
to seal the gap between the stylet and the punch to keep the core
from being extruded along the stylet and damaged and/or lost.
[0045] In the prior art, the stylets are metal wires sliding in the
metal punch tubes. This rather crude arrangement is functional but,
depending on the tissue type, temperature and closeness of fit of
the wire and the tube, some of the tissue can extrude between the
wire and the tube, leading to unpredictable losses of tissue. In
addition to the simple loss of the tissue, this causes the
additional problem of a different volume of tissue beneath the
stylet and arrays being constructed with non-uniform depths. This
non-uniformity leads to a much reduced yield of useful sections
that can be cut from the array block.
[0046] The present invention comprises the use of small pieces of
wadding or packing at the tips of the stylets to prevent this
extraneous extrusion. These pieces can preferably be elastomeric
material such as polyurethane, natural rubber or polyvinyl chloride
or the like. They can be made to fit the punches exactly by using
the punch as a tool to punch exactly the correct size disc from a
sheet of the chosen material.
[0047] Force control of the stylet
[0048] A drive for the stylet can be designed to exert prescribed
forces as well as moving to precise positions, to allow tamping of
the cores for better grip by the punches and easier removal of the
cores from the blocks.
[0049] The closest system of which the inventor is aware for
automated tissue arrayers uses only positional control of the
stylet. This has the disadvantage that the stylet can only be
withdrawn entirely out of the way of the tissue or wax cores while
they are being acquired or pushed down flush to the end of the
punch to insert the tissue core in a recipient block. Although
intermediate positions are possible in theory, they are not useful
as the automated machine has no information on the exact length of
the wax plug with which to calculate an appropriate intermediate
position for the stylet. There are combinations of tissue type, wax
type, temperature and punch geometry for which it has been a
problem to reliably extract the core from the block. Although the
punch may have cut out a core, it is not removed because it is
still held at the bottom by the block and there is not enough
friction along the sides of the punch to grip the core and break
the connection to the block at the bottom.
[0050] The present invention includes controlling the force applied
to the stylet such as by means of a pneumatic or hydraulic
cylinder. This controlled force can be set high enough to push the
core completely out of a punch into a tissue block or at an
intermediate value for tamping the core just before it is
withdrawn. The tamping compresses the core axially and thus expands
it radially against the cylindrical walls of the punch. This
increased radial force creates a stronger grip of the punch on the
core and enables the punch to extract the core. This phenomenon is
somewhat counter-intuitive as some users of earlier automated
machines thought that the axial force would push the core
completely out of the punch. Indeed it would push it out if large
forces were used to force the stylet all the way to the end of the
punch tube. Earlier descriptions of automated machines teach simple
cycles involving the stylet either being at one end of its full
stroke or the other.
[0051] The controlled force may be exerted by any number of ways
well known in the art, such as pneumatics, hydraulics, controlled
current motors, feedback systems involving force sensors on any
sort of actuator or combinations of springs and various
mechanisms.
[0052] It can be seen that there are many combinations and
permutations possible with advantages for different applications.
The key element that all have in common is the use of at least two
separate z drives.
[0053] Further, in order to increase the range or capacity of the
unattended instrument, it is possible to further provide a magazine
containing donor and/or recipient blocks, either fresh or punched,
wherein the magazine is operatively associated with said instrument
for providing blocks to said instrument and/or receiving blocks
from said instrument.
[0054] Although this invention has been described in its preferred
form with a certain degree of particularity with respect to an
instrument for creating micro-arrays with punches moveable on z
axis, it is understood that the present disclosure of the preferred
form has been made only by way of example and that numerous changes
in the details of structures and the composition of the combination
may be resorted (e.g., donor and recipient block holding pallet
moving in z direction) to without departing from the spirit and
scope of the invention.
[0055] Now that the invention has been described,
* * * * *