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At least 109 records · Page 6Linked to original sources
PubMed1986

The application of lipid-soluble stains in plastic-embedded sections.

The present study was designed to develop a routine method for direct demonstration and precise localization of lipid substances in tissue sections. A panel of lipid-rich tissues was fixed in 4% buffered formaldehyde, infiltrated, and embedded in the water-soluble plastics Technovit 7100, EFL-67, and JB-4. The use of alcohol containing fluids was avoided. Staining with the lipid-soluble dyes Sudan Black B and Oil Red O revealed excellent preservation of tissue lipids in Technovit 7100 embedded sections when compared with cryostat sections of the same tissue specimens. Lipid preservation in EFL-67 and JB-4 embedded sections was inconsistent, even when infiltration and polymerization procedures were performed at 4 degrees C. Combination of lipid-soluble dyes with the periodic acid Schiff, Jones' methenamine silver, or Gomori' reticulin method allowed for an exact localization of lipids in high-quality Technovit 7100 embedded sections. The procedure herein is easily applicable in routine histopathology practice.

Adenocarcinoma↗
PubMed2001

Rapid plastic embedding is compatible with colorimetric detection following whole mount in situ hybridization in plant specimens.

In performing in situ hybridizations, nonisotopic nucleic acid labeling coupled with colorimetric detection offers a safer, easier and more rapid alternative to using radioactively labeled nucleic acid probes and microscopic autoradiography. Whole mount in situ hybridization is also advantageous, because many samples can be processed identically and the reduced handling of specimens greatly reduces the risk of exposing tissues to RNase(s). The thickness of whole mount specimens, however, often prevents accurate determination of sites of expression within specific tissues. Although post-hybridization embedding and sectioning is a solution to this problem, the precipitate formed following the common colorimetric detection procedure is soluble in the organic solvents used for dehydration prior to embedding. We have developed a dehydration and embedding procedure that takes advantage of the compatibility of L.R. White resin containing 10% (v/v) polyethylene glycol 400, and heat polymerized. The addition of the plasticizer allows L.R. White embedded tissues to be sectioned at 10 microm providing excellent signal contrast.

Colorimetry↗
PubMed1989

Immunophenotypes of Reed-Sternberg cells: a study of 19 cases of Hodgkin's disease in plastic-embedded sections.

The immunophenotype of Reed-Sternberg (RS) cells in Hodgkin's disease (HD) has not been clearly defined, partly owing to difficulties in studying RS cells in cell suspensions or identifying them with certainty in frozen sections. We studied the immunophenotype of RS cells with a recently developed plastic section immunohistochemical technique on acetone-fixed tissues that affords superior morphological detail while preserving a wide variety of lymphoid differentiation antigens. Nineteen cases of HD [16 nodular sclerosing (NS), 2 mixed cellularity (MC), and 1 lymphocyte depleted (LD)] were embedded in plastic and stained for pan-B, pan-T, and various T-subset markers, as well as leukocyte common antigen (CD45), interleukin-2 (IL-2) receptor (CD25), and RS cell markers CD15 and CD30. RS cells were positive for CD45, CD15, CD30, and CD25, except for 3 cases (2 NS, 1 MC) that were CD15 negative and 2 cases (NS) that were CD45 negative. In 10 cases (NS), RS cells were positive for at least two pan-T-cell markers and CD4; pan-B cell markers were uniformly negative. RS cells in 6 cases (3 NS, 2 MC, 1 LD) were positive for at least one T-cell marker (CD2) and one B-cell marker (CD22). Two cases of NSHD showed no T- or B-cell marking. These data provide further evidence that RS cells in some cases of NSHD have T-cell phenotypes and that RS cells are not homogeneous in their immunoreactivity.

Antibodies, Monoclonal↗
PubMed1981

Retrospective demonstration of endogenous peroxidase activity in plastic-embedded tissues conventionally prepared for electron microscopy.

A procedure is described that permits retrospective demonstration of intracellular endogenous peroxidase activity in tissue conventionally prepared for electron microscopy, i.e., doubly fixed with aldehydes and osmium tetroxide, "stained" in block with uranyl acetate, and embedded in epoxy resins. Using sodium ethoxide, plastic was removed from 1 micrometer sections; subsequently, the sections were incubated for 20 min in diaminobenzidine solution (44 mg/100 ml) made in acetate-citric acid buffer, pH 5.6, with 0.01% hydrogen peroxide. After this treatment, the sections were rinsed, dehydrated, and mounted. Cell types known to have endogenous peroxidase activity (red blood cells, macrophages, and retinal pigment epithelium cells in our preparations) show positive granules in their cytoplasm--control sections were uniformly negative. This method, which could also be used prospectively, cytochemically demonstrates endogenous peroxidase activity upon optical microscopical examination of the treated tissues; correlative electron microscopic studies may be performed on the same tissue block, or even adjacent sections.

Acute Disease↗
PubMed2001

Distribution of cytoskeletal proteins, integrins, leukocyte adhesion molecules and extracellular matrix proteins in plastic-embedded human and rat kidneys.

OBJECTIVE: To study the distribution of cytoskeletal proteins (actin, alpha-actinin, vinculin, beta-tubulin, keratin, vimentin, desmin), adhesion molecules for cell-matrix interations (very later antigens [VLA1-61, beta1, beta2 [CD18], vitronectin receptor [alphavbeta3], CD 11b), leukocyte adhesion molecules (ICAM-1) and extracellular matrix proteins (collagen IV, fibronectin, laminin, vitronectin) in human and rat kidneys by using a superior processing and immunohistochemical staining technique. STUDY DESIGN: Human and rat kidneys were fixed in 2% paraformaldehyde, dehydrated in acetone and processed in a new, low-toxic glycol, methacrylate mixture, especially developed for immunohistochemistry. Both the glomeruli and the interstitial areas were carefully examined and scored semiquantitatively. RESULTS: Immunostained plastic sections showed excellent morphology combined with remarkably well preserved antigenicity. CONCLUSION: The above mentioned provides an excellent tool for the accurate localization of a wide variety of antigens at the light microscopic level.

Animals↗
PubMed1994

Cryo automated electron tomography: towards high-resolution reconstructions of plastic-embedded structures.

The use of fully automated data collection methods for electron tomography allows a substantial reduction in beam dose. The goal has been to develop new protocols for data collection defining optimal approaches for maintaining data self-consistency and maximizing the useful resolution of the reconstruction. The effects of irradiation and post-cure microwaving were examined for a variety of embedding media (Epon, Epox, Lowicryl) in order to quantify beam damage with the goal of identifying the most beam stable embedding medium. Surprisingly, the substantial dose reduction made possible by automated data collection did not result in a significant decrease in specimen shrinkage even for samples stabilized by pre-irradiation. We believe that the accelerated shrinkage is a direct consequence of the stroboscopic illumination patterns inherent to automated data collection. Furthermore neither the choice of embedding resin nor microwave post-curing greatly affected shrinkage. Finally, cryogenic data collection was investigated as a means to minimize the effects of secondary radiation damage. Minimal pre-irradiation coupled with low-temperature automated data collection greatly reduces shrinkage and should result in high-quality data for three-dimensional reconstructions.

Cryopreservation↗
PubMed1993

A modified trichrome stain for light microscopic examination of plastic-embedded corneal tissue.

Corneal histopathology is essential to understanding the mechanisms of corneal disease and wound healing. We have developed a light microscopic trichrome stain for 1-micron, aldehyde-fixed, osmicated, epon/resin-embedded corneal sections. The stain consists of azure II, methylene blue, and basic fuchsin. This combination of stains provides a fast and effective method to clearly differentiate corneal cells from their surrounding extracellular matrix, and chromatically separates various ECM materials within the cornea. Correlative examination by light and transmission electron microscopy (TEM) provides multilevel understanding of corneal morphology and ultrastructure. Tissues examined using this staining procedure may be subsequently examined by TEM for ultrastructural morphology. This stain has proved beneficial in our research of both cellular and extracellular constituents of the cornea.

Adolescent↗
PubMed2001

Demonstration of intravital microfissures in undecalcified plastic-embedded temporal bones with the prestaining technique.

Microfissures in the human otic capsule have been observed since the start of the century, but it was Otto Mayer, in 1930, who first realized that some of them were of intravital origin and not just processing artifacts. Since then, a small number of publications, based on decalcified temporal bones, have mostly confirmed his findings. With the introduction by Frost in the late 1950s of the undecalcified bone technique and the bulk staining technique for peripheral bones, a method was developed and refined for identifying even very small intravital microfissures (microdamage). Bulk staining of undecalcified otic capsules has not yet been used to verify the findings from the previous decalcified specimens. The present report presents our experience with the pertinent techniques, and suggests modifications and shortcuts pertinent to temporal bone research. Both large and tiny microfissures of intravital genesis are demonstrable within bulk-stained undecalcified human otic capsules. The importance of microfissures in the petrous bone in the causation of otosclerosis and perilymphatic leakage has long been discussed, and the present techniques may advance our understanding of these pathological conditions

Adult↗
PubMed1992

Immunohistochemical reactivity of neuropeptides in plastic-embedded semithin sections of the myenteric plexus in infantile hypertrophic pylorus stenosis.

Pyloric biopsies obtained at pyloromyotomy from 46 infants were studied by light and electron microscopy and compared to 8 autopsy control cases without any evidence of infantile hypertrophic pyloric stenosis (IHPS). A positive family history of this disorder was recorded in 8 cases (2 girls and 6 boys). The most frequent changes in the myenteric plexus comprised axonal alterations. In glial cells, cytoplasmic vacuolisation or an increase of intermediate filaments occurred. In ganglion cells, vacuolisation of perikaryal cytoplasm or dense bodies were observed. No obvious differences were seen between sporadic and hereditary cases. In addition to these fine structural alterations, immunohistochemistry in 6 IHPS cases and 4 controls revealed differences in the distribution of substance P, bombesin, calcitonin gene related peptide and enkephalin-like immunoreactivity within the myenteric plexus between IHPS and control cases. The immunoreactivity, however, was unevenly distributed from case to case and even within individual cases. The reduction of immunoreactivity corresponded, at least in part, to an increase of neurofilaments or abnormal organelles within axons. Increased immunoreactivity was apparently related to focal accumulation of dense cored vesicles noted in the preceding study. It is suggested that these and other changes reported interfere with the normal gastrointestinal reflex mechanisms leading to intestinal obstruction.

Female↗
PubMed2001

Immunohistochemical study during healing of free palatal mucosa grafts on plastic-embedded samples.

This immunohistochemical study describes changes in the histology and in the distribution of the basement membrane components laminin and collagen IV as well as of the cytokeratins (CK)1/2/10/11, CK5/6, CK13, CK14, CK17, CK19 during the take of free split mucosa (epithelial and connective tissue) transplants in humans up to 36 months post-operative. Histology showed a flattening of the epithelial layer within the first 2 weeks after grafting, followed initially by an increase (25-30 layers, week 6) and later on by a decrease of cell layers in the epithelium (15-20 layers, week 20). From that time onwards, clear stratification and reteridges as signs of differentiation were present. Up to day 14 of graft take, the linear staining patterns for laminin and collagen IV were interrupted, which was not observed at any later stage. During this early interval CK5/6, CK1/2/10/11, CK14 and CK17 were expressed in all epithelial layers. The reactions for CK5/6 and CK1/2/10/11 were less intensive. At 6 weeks, CK1/2/10/11 stained the intermediate and superficial layers, being consistent with findings after longer graft take. CK5/6 reacted in the basal and intermediate cell layers, and CK13, CK14 and CK17 reacted in all layers. In the following period up to week 20, CK5/6 were found in the parabasal cells of the intermediate cell layers and the basal cells. CK14 staining was confined to these cell layers too, but also showed some reaction in the superficial layers. CK13 and CK17 were still bound to all layers. At 7 months post-operative, CK5/6 and CK14 were seen in their typical localisation in the basal cell layer and the parabasal cells of the intermediate layers, CK17 was seen mainly in the intermediate layer and CK13 was seen in focal areas of all layers. Anti-CK19 reacted only with single basal and parabasal cells up to week 20. These results suggest that during healing of mucosal autografts there is a sequence of changes in the expression of cell biological differentiation markers that may involve an epithelio-connective tissue interaction before the typical patterns for the donor side were observed again on the gingiva or mucosa of the hard palate.

Adult↗
PubMed1987

Microwave-stimulated staining of plastic embedded bone marrow sections with the Romanowsky-Giemsa stain: improved staining patterns.

Staining plastic sections with the Romanowsky-Giemsa method is both time-consuming and difficult. This paper reports how the staining time can be reduced to 25 min using microwave irradiation of the staining solution. It is shown that staining results depend on the fixative used, staining temperature, dye concentration and pH of the staining solution as well as on several parameters of the microwave irradiation technique. The staining patterns are improved when compared with those obtained by conventional staining of plastic sections. The colors are more brilliant and greater contrasts are observed. Basophilia, polychromasia, and orthochromasia accompanying red cell maturation are more pronounced. For white cell maturation the initial appearance of specific granules (neutrophil, basophil, and eosinophil) is more evident. Thus, cell classification is easily accomplished using the described technique. It is suggested that microwave-stimulated staining be considered for routine use.

Animals↗