GB2144366A

GB2144366A - Casting mould for specimen bodies

Info

Publication number: GB2144366A
Application number: GB08419362A
Authority: GB
Inventors: Gerhard Moessner; Werner Behme; Manfred Berleth
Original assignee: Parke Davis and Co LLC
Current assignee: Parke Davis and Co LLC
Priority date: 1983-07-30
Filing date: 1984-07-30
Publication date: 1985-03-06
Also published as: GB8419362D0

Abstract

A casting mould (1) is provided for moulding a specimen body having a tissue specimen embedded in a matrix, the body being grippable in a microtome for cutting thin segments of the specimen. The mould has a recess (11) for receiving the specimen (3) and a polymerisable material. The mould is made of elastically deformable material to facilitate removal of the specimen body formed by hardening of the material. The mould is re-usable for making a large number of specimen bodies. The mould recess may have a depression (13) in the bottom (12) for receiving the tissue specimen. The specimen body (2a,2b) formed therein will, therefore, have a main body and a projection in which the tissue specimen is embedded. <IMAGE>

Description

SPECIFICATION Casting mould for specimen bodies This invention relates to a casting mould for specimen bodies.

German Patent Specification No. 2,939,582 dicloses a process apparatus for the embedding of tissue specimens, especially tissues with a proportion of bony constituents, in which a pretreated specimen is embedded in a settable matrix in a casting mould, for example, a glass tube. After the matrix has set, which takes place uniformly, the glass tube is broken to extract the specimen body consisting of the matrix and the tissue specimen, and the specimen body is then processed into thin sections, for example, in a conventional hard-section microtome. In this known process, a glass tube, which can be used only once, is therefore necessary for each individual specimen body.

In another known process for embedding and cutting histological specimens, prepared specimens are introduced into individual recesses in a casting mould made of polytetrafluoroethylene. A polymerisable material is then poured into the recesses without filling the recesses completely.

After this material has hardened, a separate grippable body is positioned over each recess and, in a further casting process, the matrix containing the specimen is firmly connected mechanically to the grippable body. Thus, this is a two-stage process.

An object of the present invention is to provide a re-usable casting mould, by means of which dimensionally accurate specimen bodies can be produced in one piece in a single casting operation and from which the hardened specimen bodies can easily be removed.

According to the present invention there is provided a casting mould for moulding a specimen body comprising a specimen embedded in a matrix, the casting mould comprising a body composed of elastically deformable material, the body defining at least one mould recess for receiving the specimen and polymerisable material for forming the matrix.

It is especially advantageous if the casting mould is made of silicone rubber, which has very high and long-term dimensional stability, so that a casting mould of this type can be used repeatedly for moulding dimensionally accurate specimen bodies.

The casting mould may have a planar base for supporting the mould on a surface and at least one recess in the top surface for receiving the specimen and the matrix material.

Advantageously, particularly for embedding smaller specimens, the recess has in its bottom a depression which matches the dimensions of the specimen for which it is designed. The casting mould can also have at least one further recess without such a despression which is suitable for receiving a specimen of larger dimensions.

Particularly for embedding smaller elongate specimens, for example bone-marrow biopsy specimens of the order of 4 mm x mm it is advantageous if the depression is a slit extending across the bottom of the recess. For a precise positioning of the specimen of this type, and so that it is also possible easily to remove a specimen body from the casting mould, the two end regions of each slit have opposite side walls tapering towards each other, and these wall also taper towards each other in an axial direction towards the bottom of the slit.

It becomes even easier to remove a specimen body from the elastically deformable casting mould, if the bottom of each recess is flexible so that it can be pushed inwards above the planar base surface of the casting mould with the result that the specimen body can be removed from the casting mould very simply and quickly by means of slight pressure from the direction of the base surface.

So that the specimen body can be mounted without difficulty in a microtome, each recess, which also directly forms the grippable body, advantageously has a cylindrical shape.

In the drawings: Figure 1 shows a plan view of a casting mould; Figure 2 shows a section along the sectional lines A-B of Figure 1; Figure 3 shows two specimen bodies obtained from the casting mould shown in Figure 1; Figure 4 shows a plan view of a further embodiment of a casting mould; Figure 5 shows a section along the section line C-D of Figure 4; and Figure 6 shows two specimen bodies obtained from the casting mould shown in Figure 4.

Figure 1 shows a casting mould 1 made of an elastically deformable material, preferably silicone rubber, with two rows of cylindrical recesses 11 in its two surfaces. Each recess 11 in the left-hand row of the casting mould additionally has a slit 13 in its bottom which extends across the entire width of the recess along a diameter. The longitudinal side walls 16 of the slit converge in a taper towards each end of the slit. The slits 13 are intended particularly for receiving the materialsaving embedding of smaller elongate tissue specimens, whilst the recesses 11 without the slits, on the right-hand side of the casting mould, are intended for embedding larger specimens.

The recesses 11 can of course have shapes other than cylindrical, and in cross-section each recess may be, for example, polygonal, tetragonal or square. Likewise the depressions 13 may be of polygonal, tetragonal or round shape in cross-section.

Figure 2 shows that the mould 1 has a planar base surface 14. The recess 11 on the left-hand side has in its bottom 12 a slit 13, the side surface 16 of which taper slightly converging in the axial direction away from the recess. This facilitates removal of a specimen body from the mould. The specimen body 2b formed in this recess and slit is shown in Figure 3.

The slit serves for receiving a smaller tissue specimen 3, whilst the recess 11 on the right-hand side of Figure 2 is intended for receiving a larger specimen 3.

After the specimens 3, appropriately pretreated, by fixing and desiccation, have been introduced into the slits 13 or the recesses 11, where no slits are provided, so as to rest at the bottom 15 of each slit or recess (each bottom 15 being perpendicular to the longitudinal axis of each recess, shown by a dot-and dash line) the recesses 11 are filled to the top with a polymerisable matrix material. After the matrix has hardened, the specimen bodies 2a and 2b, shown in Figure 3, incorporating the tissue specimens, can be removed in a simple manner from the mould by pressing against the base surface of the elastically deformable mould.

The casting mould 1 illustrated in Figures 4 and 5, and the specimen bodies 2a and 2b shown in Figure 6, differ from the casting mould illustrated in Figures 1 and 2, and from the specimen bodies shown in Figure 3. There are in the plate-shaped casting body 1 three rows of six recesses 11, and in half of them, that is to say in nine recesses 11, there is provided a slit 13.

In both embodiments, the specimen bodies formed can be cut into thin sections immediately on production without the necessity for initially milling away matrix material and without wasted initial cuts being carried out in which there is no tissue specimen.

Claims

1. A casting mould for moulding a specimen body comprising a specimen embedded in a matrix, the casting mould comprising a body composed of elastically deformable material, the body defining at least one mould recess for receiving the specimen and polymerisable material for forming the matrix.

2. A casting mould according to Claim 1, wherein the mould body is composed of silicone rubber.

3. A casting mould according to Claim 1, wherein the casting mould has a planar base surface, and a top surface defining said recess.

4. A casting mould according to Claim 1, wherein the body defines a depression in the bottom of the recess for receiving the specimen.

5. A casting mould according to Claim 4, wherein the depression is an elongate slit extending across the bottom of the recess.

6. A casting mould according to Claim 5, wherein each of the two end regions of the slit are defined by side walls which converge towards each other in the direction away from the centre of the slit.

7. A casting mould according to Claim 6, wherein the side walls of the slit converge slightly in the direction away from the recess along the axis of the recess.

8. A casting mould according to Claim 1, wherein the portion of the mould defining the bottom of the recess is flexible so that it can curve inwards in deformation of the base surface.

9. A casting mould according to Claim 1, wherein the recess is cylindrical.

10. A casting mould substantially as herein described with reference to and as shown in the accompanying drawings.