Histological staining procedure

A process which is important for the dyeing of cotton and for histological staining procedures is the addition of what are known as direct dyes to cellulose. There are various theories about the type of bonding [53, 54]. Obviously hydrogen bonds and hydrophobic interactions are important here, but in view of what has already been said, even these weak interactions should prove capable of influencing the chromophoric groups dissymmetrically. 

Immunohistology should not be regarded as an empirical procedure similar to other histological stains. Immunohistology is different in that it entails many more steps to perform and success cannot be monitored until completion of the entire procedure. It is more akin to a... 

Bone samples for aluminium analysis have been taken from the iliac crest at the time of biopsy or at autopsy (Alfrey et al.. 1976 Maloney et al., 1982) and the specimen placed in an Al-free plastic container. Bone for histological staining is fixed in 10% buffered formalin (Maloney et al., 1982). Crapper et al. (1976) analyzed brain samples from specific areas of the cerebral cortex and from subcortical area. Alfrey et al. (1976) analyzed brain samples from frontal cortex. Whole brain as well as white and grey matter were analyzed. A description of how the specimen was handled before analysis was not provided. Crapper et al. (1976) transported and stored brain samples frozen in Al-free plastic containers and performed dissection from the frozen specimen in a dust-controlled room. All instruments and gloves were rinsed in aluminium-free water. At frequent intervals, this entire procedure was performed on standard homogenized freeze-dried brain powder to ensure little or negligible aluminium contamination. 

DRURY, R.A.B. and WALLENGTON, E.A. 1980. General staining procedures. In Carelton s Histological Techniques, ed Drury, R.A.B. and WaUington, E.A. Oxford Medical Pnblication, Oxford University Press, 125-150. 

The nervous system contains an unusually diverse set of intermediate filaments (Table 8-2) with distinctive cellular distributions and developmental expression [21, 22]. Despite their molecular heterogeneity, all intermediate filaments appear as solid, rope-like fibers 8-12 nm in diameter. Neuronal intermediate filaments (NFs) can be hundreds of micrometers long and have characteristic sidearm projections, while filaments in glia or other nonneuronal cells are shorter and lack sidearms (Fig. 8-2). The existence of NFs was established long before much was known about their biochemistry or properties. As stable cytoskeletal structures, NFs were noted in early electron micrographs, and many traditional histological procedures that visualize neurons are based on a specific interaction of metal stains with NFs. 

Histology. Whole mussels were fixed for 1-2 days in Helly s fluid (10) and stored in 70% ethanol. Tissue was blocked at 2 mm thickness, embedded in paraffin, sectioned at about 7 ym, stained with hematoxylin and eosin, and mounted on glass slides using standard procedures. 

In order to perform this task the staff must first retrieve the requisition for the case and be able to confirm that the appropriate procedure was requested at the time of accession. When the identity of the patient (and/or case number) is confirmed, the next assessment required is to confirm that the number of tissue blocks submitted has produced the appropriate number of slides and stains. This task requires a well trained technician who is attentive to details and has a thorough understanding of the operations in the histology laboratory. If the case is incomplete the technician must troubleshoot the problem in order to locate the missing materials. 

Figure 11.8. Detection of NOS-dependent S-nitrosylation in vivo, a Immunochemical detection procedure. A primary antibody directed against nitrosothiol groups was used in combination with an enzyme-linked secondary antibody. The dye released by the enzyme is insoluble and thus will precipitate close to the site of formation, b S-nitrosylationinaorticrings. Samplesweie treated with Phenylephrine (PE), acetylcholine (Ach), and the inhibitor N-methylarginine (L-NAME) as indicated. Brown stain deposits indicate S-nitrosylation. The traces above the histology panels illustrate the contraction and relaxation responses evoked by the dmgs.

Detection of metastatic disease may occasionally require the use of immunohistochemical stains in challenging specimens such as postradiation lymph nodes. Subtle post-treatment residual tumors can be detected clinically using PET/CT scans, but histologically these isolated foci may show only granulomatous or necrotic tissue without viable tumor. In these cases, cytokeratin stains can be helpful to identify the etiology of the necrotic deposits. Sentinel lymph node examinations are occasionally used in head and neck surgery. Currently no standard practice for using immunohistochemistry to examine the sentinel lymph nodes exists, and indeed the procedure is fairly unreliable for mucosally based tumors. 

For the surgical pathologist, the appropriate triage and examination of the SLN is of utmost importance, but even here some controversy exists. When the SLN mapping procedure began to be the standard of care a few years ago, the SLNs were examined histologically by multiple levels and cytokeratin stains on at least two... 

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