Neutral buffered formalin sections

Compound (Miles Laboratories, Elkhart, IN), snap-frozen, and cut into sections for comparison with paraffin-embedded cell sections (3) FFPE Cell Blocks Six cell pellets were fixed in 10% neutral buffered formalin immediately after harvest, at room temperature for 6,12,24h, 3,7, and 30 days, respectively. For further comparison with the cell model system, recently collected sample of human breast cancer tissues were processed by OCT-embedding and snap-freezing the corresponding routine FFPE block that was obtained from the Norris Cancer Hospital and Research Institute at the University of Southern California Keck School of Medicine (USC). This tissue block was processed routinely (formalin-fixed 24h and processed by automatic equipment). 

Fix the specimen m neutral buffered formalin and embed in wax Cut 3—5 pm sections. 

Surgical breast biopsy specimens are first fixed with neutral buffered formalin (4%) for 4-6 hr, followed by zinc-formalin for 2 hr. Paraffin sections (5 xm thick) are placed on silane-coated slides, dried on a slide warmer (60°C) for 1 hr and then in an oven (60°C) for an additional 1 hr. Deparaffinized sections are digested with 0.1% trypsin in PBS at 37°C for 15 min. The sections are placed in 10 mM citrate buffer (pH 6.0) and transferred into a water bath (80° or 90°C) for 2 hr. After a 20-min cooling period, the sections are rinsed... 

For the HercepTest to be valid, it must be performed exactly according to the manufacturer s directions. The tissue must be fixed in 10% neutral buffered formalin or Bouin s solution. Sections of paraffin-embedded tissues should be cut 3-A xm thick and processed in a standard tissue processor. Epitope retrieval should be carried out in a water bath instead of in a microwave oven. Water is used because it provides more uniform and... 

Figure 7.3 A. Human psoriatic tissue (200x). B. Normal human skin (200x). Both samples were immunostained with caspase 14 antibody. Punch biopsies (4 mm) of normal and psoriatic skin samples were obtained from different patients who provided written, informed consent under an IRB-approved protocol. Samples were fixed in 10% neutral-buffered formalin, paraffin embedded, cut to 5-pm sections, and stained with caspase 14 antibody by immunohistochemistry.

For smaller laboratories, the work involved in validation is often difficult, but there are two alternatives. Users can choose a system with an existing standardized and validated protocol and validated interpretation system. Commercially available kits generally provide these, and when utilized exactly as described in the kit insert, are guaranteed to provide diagnostically useful results. A second option would be to use one of the more common standard systems of fixatives with known antibodies, in which publication data has provided some evidence of functionality. As an example, a laboratory could use a 10% neutral buffered formalin fixation with a standard protocol, followed by a biotin-streptavidin HRP system, using a monoclonal antibody combination called AE1/AE3. This has been proven to be a reliable measure of cytokeratin in tissue sections. 

Specimens from biopsies, excisions or resections must be handled as soon as possible to preserve the tissue for FISH. Specimens should be preserved in 10% neutral-buffered formalin (NBF), preferably as 3-4 mm blocks fixed for 18-24 hours followed by dehydration and embedment in paraffin. Sections should be cut into 4-6 pm, mounted on positively charged slides (e.g. SuperFrost Plus, Mentel-Glaser, Thermo Scientific) and adhered to the slide by baking at 60°C for approximately 1 hour. 

Fix kidney halves overnight at 4°C in 10% neutral buffered formalin (Fisher), embed in paraffin, and section at 3 pm. 

Human tissue should be fixed in 10% neutral buffered formalin and then dehydrated for embedding in paraffin. Paraffin is nonaqueous embedding medium, so the tissue blocks must have the water removed or be dehydrated. Dehydration is done in organic solvents such as alcohol, acetone, xylene, or toluene. After dehydration, the tissue blocks are embedded with liquid (warm) paraffin. When cooled, the wax embedded block is sectioned on a rotary microtome. Before immunocytochemistry can be performed on the resulting tissue sections, they must be rehydrated by processing with the same organic solvents back to water. Thus, the dehydration and rehydration steps are needed before immunohistochemistry. 

The relevant constructs (n=5) were then fixed with a 10% neutral-buffered Formalin solution overnight followed by paraffin wax embedding. Sections of 5 pm thickness were sliced from the embedded paraffin construct with a microtome. Histological evaluation was carried out after the sections were deparaffinized, rehydrated and was stained by Hematoxylin and Eosin (H E) staining. 

Tissues are fixed with 10% neutral phosphate-buffered formalin and embedded in paraffin, and sections (5 pm thick) are mounted on poly-L-lysine-coated slides heated at 60°C for 30 min. The sections are deparaffinized in four changes of xylene and then rehydrated in a descending series of ethanol. Endogenous peroxidase activity is quenched by immersing the sections in 1% H202 in distilled water for 5 min. The sections are rinsed in three changes of distilled water, transferred to a moist chamber, and covered with PBS. 

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