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Fig. 1 TMA outline example. The TMA has been divided into four subsections to facilitate navigation during microscopy.

2. Taking a cylindrical sample from the tissue sample (donor) paraffin block.

3. Placing the cylindrical tissue sample in the premade hole in the recipient block.

Commercially available or various kinds of homemade tissue-arraying systems are used for TMA manufacturing. Exact positioning of the tip of the tissue cylinder at the level of the recipient block surface is crucial for the quality and the yield of the TMA block. Placing the tissue too deeply into the recipient block results in empty spots in the first sections taken from the TMA block. When the tissue cylinder is not positioned deep enough, empty spots are created in the last sections taken from this TMA. If tissue cylinders protrude, they may be gently pressed deeper into the prewarmed TMA block (40oC for 10 min) by using a glass slide.

Array Sectioning

TMAs can be sectioned like standard paraffin blocks by using regular microtomes. A special tape sectioning kit (Instrumedics Inc., NJ, USA) may be utilized to facilitate cutting, especially for large TMAs. The tape system leads to highly regular nondistorted sections (which are ideal for automated analysis) and helps to prevent arrayed samples from floating off the slide during incubation and washing steps.

TMAs from Frozen Tissues

TMAs may also be manufactured from frozen tissues.[1] Here recipient blocks are made from OCT compound (Sakura Finetek, the Netherlands) that is frozen down in a Tissue-Tek standard cryomold. The resulting OCT block is mounted on top of a plastic biopsy cassette. During the

Table 1 Example file for TMA construction

Location

Coordinates

Location

Coordinates

Location

Coordinates

A 1a

0/0

A 2a

0/800

A 3a

0/1600

A 1b

800/0

A 2b

800/800

A 3b

800/1600

A 1c

1600/0

A 2c

1600/800

A 3c

1600/1600

A 1d

2400/0

A 2d

2400/800

A 3d

2400/1600

A 1e

3200/0

A 2e

3200/800

A 3e

3200/1600

A 1f

4000/0

A 2f

4000/800

A 3f

4000/1600

A 1g

4800/0

A 2g

4800/800

A 3g

4800/1600

A 1h

5600/0

A 2h

5600/800

A 3h

5600/1600

A 1i

6400/0

A 2i

6400/800

A 3i

6400/1600

A 1k

7200/0

A 2k

7200/800

A 3k

7200/1600

A 1l

8000/0

A 2l

8000/800

A 3l

8000/1600

A 1m

8800/0

A 2m

8800/800

A 3m

8800/1600

A 1n

9600/0

A 2n

9600/800

A 3n

9600/1600

A 1o

10400/0

A 2o

10400/800

A 3o

10400/1600

A 1p

11200/0

A 2p

11200/800

A 3p

11200/1600

A 1q

12000/0

A 2q

12000/800

A 3q

12000/1600

A 1r

12800/0

A 2r

12800/800

A 3r

12800/1600

Fig. 2 Examples of stained tissue sections. Hematoxylin & eosin (H&E)-stained sections of (A) a TMA from formalin-fixed, paraffin-embedded tissues containing 540 tissue spots and (B) a TMA from frozen tissue containing 228 tissue spots. Each tissue spot measures 0.6 mm in diameter. Missing samples result from the sectioning/staining process or indicate samples that are already exhausted. Note that the distance between spots is larger on the frozen TMA compared to the paraffin TMA. (C) Magnified view of an H&E-stained 0.6-mm tissue spot of a bladder carcinoma. (D) Immunohistochemistry against the Her2/neu protein in a breast cancer sample using the DAKO HercepTest®. (E) FISH analysis of centromere 17 (green signals) and the HER2 gene (red spots) in cell nuclei (blue staining) of a tissue spot (630 x). The high number of HER2 signals indicates a gene amplification. (F) RNA in situ hybridization on a frozen TMA made from normal and malignant kidney tissues. A radioactively labeled oligonucleotide was used as a probe against vimentin mRNA. The black staining intensity indicates the level of mRNA in each tissue spot. (View this art in color at www.dekker.com.)

Fig. 2 Examples of stained tissue sections. Hematoxylin & eosin (H&E)-stained sections of (A) a TMA from formalin-fixed, paraffin-embedded tissues containing 540 tissue spots and (B) a TMA from frozen tissue containing 228 tissue spots. Each tissue spot measures 0.6 mm in diameter. Missing samples result from the sectioning/staining process or indicate samples that are already exhausted. Note that the distance between spots is larger on the frozen TMA compared to the paraffin TMA. (C) Magnified view of an H&E-stained 0.6-mm tissue spot of a bladder carcinoma. (D) Immunohistochemistry against the Her2/neu protein in a breast cancer sample using the DAKO HercepTest®. (E) FISH analysis of centromere 17 (green signals) and the HER2 gene (red spots) in cell nuclei (blue staining) of a tissue spot (630 x). The high number of HER2 signals indicates a gene amplification. (F) RNA in situ hybridization on a frozen TMA made from normal and malignant kidney tissues. A radioactively labeled oligonucleotide was used as a probe against vimentin mRNA. The black staining intensity indicates the level of mRNA in each tissue spot. (View this art in color at www.dekker.com.)

arraying process, it is important to keep the tissue in the needle frozen. This can be carried out by cooling the needle with a piece of dry ice before punching, and while dispensing the tissue core into the recipient block, 4- to 10-p.m sections of the whole block are cut from the array block, using a cryostat microtome with or without a Tape Transfer System and slides.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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