GB2253711A

GB2253711A - Marking specimen slides

Info

Publication number: GB2253711A
Application number: GB9203679A
Authority: GB
Inventors: Michael Feldman
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-02-20
Filing date: 1992-02-20
Publication date: 1992-09-16
Also published as: GB9103540D0; GB9203679D0

Abstract

Apparatus for marking a specimen slide comprising an energisable aiming device 25 to provide a localised physical effect, such as an electric discharge, the aiming device being movable with respect to a specimen slide (20) having a surface provided with a coating responsive to said physical effect eg. electrosensitive, the aiming device and specimen slide being in use arranged in overlying relation such that the specimen slide is locally marked upon energising of the aiming device between the cross piece 26. The localised physical effect may also be ultra violet, heating, potential difference effect to provide a local colour change in the coating. Specified heat sensitive layer is a binder, solvent, trichloroethanoic acid and a pH indicator. <IMAGE>

Description

HARKING SPECIMEN SLIDES DESCRIPTION This invention relates to the marking of specimen slides and is particularly concerned with methods and apparatus to effect such marking and also with slides (and/or parts associated therewith) responsive to such marking.

Conventionally, laboratory inspection of specimen slides is by means of a microscope and is generally a two-stage procedure. Firstly, the specimen slide - which comprises a glass carrier plate supporting the specimen and surmounted by a glass cover plate - is microscope inspected by a first ("stage 1") technician who appropriately marks the specimen slide if any indication (however remote or tentative) is found of the condition being searched. The marked specimen slide is then passed to a more experienced or better qualified ("stage 2") technician who considers the marked area of the specimen slide to determine more precisely whether or not the indicated condition is indeed present. With such an arrangement, a single "stage 2" technician can serve the output of several (e.g. six or seven) "stage 1" technicians and thus provide an efficient laboratory service.

In order to mark the specimen slide, it has heretofore been necessary for the "stage 1" technician firstly to move the lens body of the microscope arcuately and/or laterally to reveal the specimen slide and then, by means of an inked marking pen (e.g. a conventional felt-tipped pen or stylus and photo-opaque ink) to produce a mark adjacent to (e.g.

draw a circle around) the area of the specimen slide containing the identified indication.

This method is inefficient in that it is time consuming and ean lead to errors in marking of the specimen slide. It is therefore desirable to provide means whereby these and/or other disadvantages of the prior art may be overcome.

According to a first aspect, this invention provides apparatus for marking a specimen slide comprising an energisable aiming device to provide a localised physical effect, the aiming device being movable with respect to a specimen slide having a surface provided with a coating responsive to said physical effect, the aiming device and specimen slide being in use arranged in overlying relation such that the specimen slide is locally marked upon energising of the aiming device. Advantageously the said physical effect is an electrically generated effect, and is caused by electrical energising of the aiming device.

Preferably the coated surface of the specimen slide is the top face of the cover plate, and the aiming device is in use positioned above the specimen slide between it and the objective lens of the microscope.

Alternatively (though less practical) the coated surface may be the bottom face of the support plate with the aiming device in use positioned below the specimen slide.

In another alternative a UV sensitive coating may be incorporated in a bonding medium between the support plate and cover plate so as to effect a local colour change in response to a W beam.

Preferably the aiming device is movably mounted directly upon the coated cover plate of the specimen slide.

Advantageously, in one arangement, the aiming device comprises at least one pair of electrical conductor elements disposed with their free ends adjacent one another such as to provide an electrical discharge between them upon energisation of the aiming device, the coating being responsive to said electrical discharge.

According to a second aspect of this invention there is provided a transparent or translucent plate for a specimen slide having on at least one surface a coating responsive to a vicinal electric effect (e.g. discharge, heating, potential difference or the like) to provide a local colour change in the coating.

The plate may be the support or carrier plate of the specimen slide or, as is preferred, may be the cover plate of the specimen slide.

By way of non-limiting example, one embodiment of this invention will now be described with reference to the accompanying drawings of which: Figure 1 is a schematic vertical section through apparatus according to this invention, and Figure 2 is a schematic plan view of parts of the apparatus of Fig. 1.

As illustrated in Fig 1, a conventional microscope 10 has a lens body 11 mounted above a bed 13 that is centrally apertured at 15 to permit illumination from a light source (not shown) to be reflected by a mirror 16 through the aperture 15 and onto the underside of a specimen slide 20.

The specimen slide 20 in this embodiment comprises a conventional glass carrier plate 24 supporting the specimen to be inspected and surmounted by a glass cover plate 21. The cover plate 21 is provided on its upper surface with a transparent or translucent coating (e.g. up to 2 microns thick) responsive to a vicinal electric effect (e.g. discharge, potential difference, or the like) to provide a colour change in the coating.

A cursor-like aiming device 25 mounted upon the slide 20 has two enlarged hand-grip portions 22 at each end of a flat transparent plate 23. A hair-like cross-piece 26 is , ix provided centrally of the plate 23 and this cross-piece 26 comprises a pair of fine metallic elements having a small gap between their ends adjacent to one another such as to provide an electric effect (e.g. a discharge) when a potential difference is applied across the gap. An electrical supply to these conductive elements of the cross- piece 26 is derived from a mains source (preferably via a step-down transformer) or from a battery, e.g. housed within one of the hand-grip portions 22, the circuit including a push-to-close switch provided either at an end one of the hand-grip portions 22 so as to be finger-operable by the technician or (as illustrated) by a foot-switch that is foot operable by the technician.

In use, when the technician identifies an area of the specimen which has a possible or definite indication of the condition being searched, he moves the cursor-like device 25 until that area is encircled or within (or at least closely adjacent) the hair-like cross-piece 26, and then operates the electric switch. The resultant electrical effect across the gap between the free ends of the cross-piece's two elements provides a resultant local colour change in the coating on the cover plate 21. This is achieved very quickly and without requiring movement of the lens body 11 away from the line of viewing of the area being marked.

It will be appreciated that the invention is not limited to the embodiment illustrated, but that other constructions and arrangements are possible without departing from the scope and/or principles of this invention. For example, the cover plate 21 may be coated on both major surfaces to avoid any confusion in use as to which surface must be in use placed uppermost. Alternatively, the marking may be provided by aiming device 25 acting upon the underside of the slide specimen's support plate 24, the support plate 24 being provided on its lower major surface (and optionally on its upper major surface too) with the said coating.

Furthermore, in all of the above-described embodiments and modifications, the cross-piece target 26 of the aiming device 25 may have its hair-line conductive elements of continuous form so that, upon electrical energising of the device 25, a localised heating effect is created and this electrically-generated heating causes a vicinal colour change in the coating. The continuous conductive target 26 may be V-shaped or arrow-shaped to 'point' to a desired area of the coated slide, or alternatively may be an almost circular C-shape to encompass the area to be marked.

For example, the slides may be coated with a heat sensitive coating which changes colour irreversibly when subject to a temperature change, e.g. 100-120"C, by the application of moderate heat for a short period, e.g. 1 second. The coating may contain 'an unstable acid which decomposes when heated, and a pH indicator which is one colour in the presence of the acid and another colour when the acid is decomposed.

A suitable coating that will undergo a local colour change when subjected to such a localised heating effect may comprise: (a) a polymer dissolved in a volatile solution, (b) a heat-responsive composition that is stable at room temperature but becomes unstable when heated, and (c) a changeable-colour composition that is soluble in said heat-responsive composition and that changes colour when the heat-responsive composition becomes unstable.

A preferred form of constituent (a) is a polyvinyl chloride copolymer [CASS No. 9003-22-9) dissolved in tetrahydro furan (THF) [1693-74-9].

A preferred form of constituent (b) is trichloroethanoic acid (CASS No.76-03-9).

A preferred form of constituent (c) is dimethyl yellow indicator (CASS No. 60-11-7).

One particularly preferred composition or formulation for such a coating comprises: PVC [9003-22-9] lg Tetrahydrofuran (1693-74-9] 4g trichloroethanoic acid [76-03-9] 0.2g dimethyl yellow indicator (60-11-7] 0.03g Such a coating formulation may be coated onto glass slides by a squeegee blade or Meyer bars (No.4 and 2). The coating dries a translucent pinkish/red colour and normally remains stable at room temperature for many months - possibly for 5 years or more.

A heated element, such as the electrically conductive "hair-piece" target 26, when applied to the coating for about 1 second, can heat the coating from room temperature to above 100 (e.g. to about 120 C) such as to render the acid unstable and/or cause it to decompose. The pH indicator provided by the dimethyl yellow indicator effects a local colour change in the coating to a distinct but translucent yellow that is in clearly visible contrast with respect to the pinkish/red remainder of the coated plate.

It will be appreciated that polymers other than PVC can be used. Examples include polyvinyl acetate, ethylcellulose, nitrocellulose, cellulose acetate. However, PVC is particularly preferred because it is non-tacky and relatively scuff resistant.

It will be appreciated that solvents other than THF can be used provided they dissolve all the components and are reasonably volatile. 2-Butanone or cyclohexanone could be substituted in the above formulation.

It will be also appreciated that the dimethyl yellow indicator can be susbstituted by any other pH indicator that is soluble in the selected solvent and has appopriately different, distinct colours above and below the pH value at which the acid decomposes or becomes unstable (to effect a colour change in the indicator).

Examples of such alternative indicators include bromophenol blue, bromocresol purple, bromocresol green, neutral red, bromothymol blue, thymol blue, cresol red, and the like. It is considered that the most appropriate colour change to be effected would be from a light colour to dark colour, e.g.

by using bromophenol blue as the indicator with its yellow to blue colour change.

Other modifications and embodiments of the invention will be readily apparent to those skilled in this art. (In one example, the heating of the last-mentioned embodiments) need not be directly via a heated wire but may conceivably be via a jet of hot air from a fan heater. In another example, the coating is responsive to ultra-violet radiation and is included in a formulation for a bonding medium between the support plate and the cover plate so that a local colour change can be effected by a W beam.) All such modifications and embodiments are to be deemed within the ambit and scope of the invention claimed, and the invention is not to be deemed limited to the particular embodiment(s) hereinbefore described which may be varied in construction, methodology and detail without departing from the scope of the patent monopoly hereby sought.

Claims

1. Apparatus for marking a specimen slide comprising an energisable aiming device to provide a localised physical effect, the aiming device being movable with respect to a specimen slide having a surface provided with a coating responsive to said physical effect, the aiming device and specimen slide being in use arranged in overlying relation such that the specimen slide is locally marked upon energising of the aiming device.

2. Apparatus according to Claim 1 wherein the said physical effect is an electrically generated effect, and is caused by electrical energising of the aiming device.

3. Apparatus according to Claim 1 or Claim 2, wherein the coated surface of the specimen slide is the top face of the cover plate, and the aiming device is in use positioned above the specimen slide between it and the objective lens of the microscope.

4. Apparatus according to Claim 1 or Claim 2, wherein the coated surface is the bottom face of the support plate, and the aiming device is in use positioned below the specimen slide.

5. Apparatus according to any one of Claims 1 to 3, wherein the aiming device is movably mounted directly upon the coated cover plate of the specimen slide.

6. Apparatus according to any preceding Claim, wherein the aiming device comprises at least one pair of electrical conductor elements disposed with their free ends adjacent one another such as to provide an electrical discharge 'between them upon energisation of the aiming device, the coating being responsive to said electrical discharge.

7. Apparatus according to any one of Claims 1 to 5, wherein the aiming device comprises means to provide a beam of ultra-violet radiation, and said coating is responsive thereto to effect a consequential colour change over an area thereof exposed to said beam.

8. Apparatus according to Claim 7, wherein said coating is provided at the interface between the cover plate and the support plate.

9. Apparatus according to Claim 7 or Claim 8, wherein the said coating is incorporated in a formulation providing a resin-based bonding medium between the cover plate and the support plate.

10. Apparatus according to any one of Claims 1 to 5, wherein the aiming device comprises an electrically conductive element to provide a heating effect when energised, the coating being responsive to said heating effect.

11. Apparatus according to Claim 10 and with a specimen slide having a said coating which comprises an unstable acid which decomposes when heated, and a pH indicator which is one colour in the presence of the acid and another colour when the acid is decomposed.

12. Apparatus according to Claim 10 or 11, wherein the coating comprises: (a) a polymer dissolved in a volatile solution, (b) a heat-responsive composition that is stable at room temperature but becomes unstable when heated, and (c) a changeable-colour composition that is soluble in said heat-responsive composition or said volatile solution and that changes colour when the heat responsive composition becomes unstable.

13. Apparatus according to Claim 12, wherein constituent (a) is selected from one or more of a polyvinyl chloride copolymer, polyvinyl acetate, ethylcellulose, nitrocellulose, and cellulose acetate.

14. Apparatus according to either of Claims 12 or 13, wherein the solvent for constiuent (a) is selected from one or more of tetrahydrofuran (THF), 2-butanone, and cyclohexanone.

15. Apparatus according to any one of Claims 12 to 14, wherein constituent (b) comprises trichloroethanoic acid.

16. Apparatus according to any one of Claims 12 to 15, wherein constituent (c) comprises a pH indicator selected from dimethyl yellow, bromophenol blue, bromocresol purple, bromocresol green, neutral red, bromothymol blue, thymol blue, and cresol red.

17. Apparatus according to any one of Claims 10 to 16 and with a specimen slide coated with a composition comprising PVC in solution, a heat-responsive composition that is stable at room temperature but becomes unstable when heated, and a changeable-colour composition soluble in said heat-responsive composition and that changes colour when the heat-responsive composition becomes unstable.

18. Apparatus and slide according to Claim 17, wherein the PVC is in a solution of tetrahydro-furan (THF).

19. Apparatus and slide according to Claim 17 or Claim 18, wherein the heat-responsive composition comprises trichloroethanoic acid.

20. Apparatus and slide according to any one of Claims 17 -to 19, wherein the changeable-colour composition comprises dimethyl yellow indicator.

21. Apparatus according to any one of Claims 17 to 20, wherein the coating comprises: PVC [9003-22-9] lg Tetrahydrofuran [1693-74-9] 4g trichloroethanoic acid [76-03-9] 0.2g dimethyl yellow indicator [60-11-7] 0.03g

22. Apparatus substantially as herein described with reference to and/or as illustrated in the accompanying drawings.

23. A transparent or translucent plate for a specimen slide having on at least one surface a coating responsive to a vicinal physical effect (e.g. electric discharge, potential difference, ultra-violet radiation, heating, or the like) to provide a local colour change in the coating.

24. A transparent or translucent plate according to Claim 23, wherein the coating is responsive to vicinal electric discharge.

25. A transparent or translucent plate according to Claim 23, wherein the coating is responsive to vicinal electric potential difference.

26. A transparent or translucent plate according to Claim 20, wherein the coating is responsive to impingement by a beam of ultra-violet radiation.

27. A transparent or translucent plate according to Claim 20, wherein the coating is responsive to vicinal heating.

28. A transparent or translucent plate according to Claim 27, wherein the coating comprises an unstable acid which decomposes when heated, and a pH indicator which is one colour in the presence of the acid and another colour when the acid is decomposed.

29. A transparent or translucent plate according to Claim 27 or 28, wherein the coating comprises: (a) a polymer dissolved in a volatile solution, (b) a heat-responsive composition that is stable at room temperature but becomes unstable when heated, and (c) a changeable-colour composition that is soluble in said heat-responsive composition or said volatile solution and that changes colour when the heat responsive composition becomes unstable.

30. A transparent or translucent according to Claim 29, wherein constituent (a) is selected from one or more of a polyvinyl chloride copolymer, polyvinyl acetate, ethylcellulose, nitrocellulose, and cellulose acetate.

31. A transparent or translucent plate according to either of Claims 29 or 30, wherein the solvent for constituent (a) is selected from one or more of 2-butanone, tetrahydrofuran (THF), and cyclohexanone.

32. A transparent or translucent plate according to any one of Claims 29 to 31, wherein constituent (b) comprises trichloroethanoic acid.

33. A transparent or translucent plate according to any one of Claims 29 to 32, wherein constituent (c) comprises a pH indicator selected from dimethyl yellow, bromophenol blue, bromocresol purple, bromocresol green, neutral red, bromothymol blue, thymol blue, and cresol red.

34. A transparent or translucent plate according to any one of Claims 27 to 33 coated with a composition comprising PVC in solution, a heat-responsive composition that is stable at room temperature but becomes unstable when heated, and a changeable-colour composition soluble in said heat-responsive composition and that changes colour when the heat-responsive composition becomes unstable.

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35. A transparent or translucent plate according to Claim 34, wherein the PVC is in a solution of THF (tetrahydrofuran).

36. A transparent or translucent plate according to Claim 34 or Claim 35, wherein the heat-responsive composition comprises trichloroethanoic acid.

37. A transparent or translucent plate according to any one of Claims 34 to 36, wherein the changeable-colour composition comprises dimethyl yellow indicator.

38. A transparent or translucent plate according to any one of Claims 34,to 37, wherein the coating comprises: PVC [9003-22-9] lg Tetrahydrofuran (1693-74-9] 4g trichloroethanoic acid [76-03-9] 0.2g dimethyl yellow indicator [60-11-7] 0.03g

39. A transparent or translucent plate according to any one of Claims 34 to 38 and constituting the support or carrier plate of a specimen slide.

40. A transparent or translucent plate according to any one of Claims 34 to 38 and constituting the cover plate of a specimen slide.

41. A transparent or translucent plate for a specimen slide substantially as herein described with reference to and/or as illustrated in the accompanying drawings.