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At least 19 recordsLinked to original sources
PubMedDate not supplied

Exploiting the "toothpick effect" of the Cytobrush by plastic embedding of cervical samples.

The introduction of the combined spatula-Cytobrush sampling method has increased the diagnostic accuracy of cervical cytology. However, the smears from a small number of cases contained epithelial fragments dislodged by the "toothpick effect" of the Cytobrush. Due to their thickness, these epithelial fragments in the smears are very difficult (if not impossible) to scrutinize and are thus undiagnosable. The presence of only such fragments in smears led to false-negative diagnoses in two cases of invasive carcinoma. To solve this problem, these epithelial fragments were embedded in plastic, with thin sections prepared from the blocks. This paper presents the morphologic features and diagnostic accuracy of 77 such problem cases (found among 50,000 cases with spatula-Cytobrush smears) to which this method was applied. In almost all cases, the diagnosis on the plastic-embedded sections matched the diagnosis on the colposcopically directed biopsy. Of these 77 patients, the biopsy diagnosis showed 5 severe dysplasias, 6 carcinomas in situ, 1 squamous-cell carcinoma, 2 adenocarcinomas in situ and 2 adenocarcinomas. In addition, data are presented concerning the nuclear-size and shape-factor differences in smears versus plastic-embedded sections, and the stereologic consequences of smearing and cutting these epithelial fragments are discussed. These plastic-embedded sections are well suited for use in quantitative microscopy, as well as for diagnostic purposes.

Adenocarcinoma↗
PubMed1977

Modifications of the Goldner and Gomori one-step trichrome stains for plastic-embedded thin sections of bone.

Modifications of the trichrome stains by Goldner and Gomori are described. They provide two reliable methods for identifying osteoid seams, bone cells, and other structures in bone embedded in plastic. Trichrome stains for paraffin-embedded soft tissue are not compatible with plastic-embedded bone. These modifications work well with most of the plastic embedding media in routine use.

Bone and Bones↗
PubMed1990

Quantitative and qualitative characteristics of the stages and transitions in the cycle of the rat seminiferous epithelium: light microscopic observations of perfusion-fixed and plastic-embedded testes.

The stages of the cycle in the rat seminiferous epithelium are illustrated for testes fixed by vascular perfusion and embedded in plastic resins. Improved cellular resolution in plastic sections permitted a clearer demarcation of the stages than in paraffin. Quantitative data are presented to support the recognition of stages, particularly those in transition. Stages IV, V, VII, XI, and XII had the highest frequencies of transitional characteristics. Stage IV was redefined to be more consistent with the occurrence of a high percentage of mitotic figures and to clarify transitions in this stage. Although the resolution of cellular detail was greatly improved with the use of plastics, the thinner sections contained fewer identifying features together within a single tubule cross section and sometimes major characteristics were absent. Therefore, additional characteristics were used for stage classification, such as nuclear diameter and the presence or absence of mitotic figures. A binary decision key is provided to improve consistency among laboratories in the identification of the stages in plastic-embedded testes.

Acrosome↗
PubMed1995

Immunohistochemical staining of plastic embedded bone marrow trephine biopsy specimens after microwave heating.

AIMS: To investigate (1) whether adequate immunohistochemical staining can be achieved on sections cut from plastic embedded bone marrow trephine biopsy specimens after microwave heating in citrate buffer; and (2) whether this immunohistochemical staining is comparable with that achieved on routine sections cut from paraffin wax embedded trephine biopsy specimens after decalcification procedures. METHODS: Sixty five consecutive bone marrow trephine biopsy specimens of more than 1 cm in length were divided transversely into two equal parts. One part was processed in paraffin wax followed by decalcification. The other part was embedded in the epoxyresin Polarbed 812 followed by the cutting of 1 micron sections. Both parts underwent immunohistochemical staining by an identical panel of antibodies. With Polarbed 812 plastic embedded sections, microwave heating in citrate buffer was undertaken before the application of antisera. RESULTS: On sections cut from plastic embedded material, immunohistochemical staining was generally satisfactory, easy to interpret and comparable with that achieved with paraffin wax embedded material. Exceptions were antibodies to neutrophil elastase and CD61 where immunostaining was consistently negative on plastic embedded sections. Immunohistochemical staining for CD20 was consistently more reliable on plastic embedded sections. CONCLUSIONS: The results provide evidence that, with few exceptions, satisfactory immunohistochemical staining is possible on plastic embedded bone marrow trephine biopsy specimens after microwave heating in citrate buffer. This, combined with the advantage of superior cellular morphology with semi-thin (1 micron) sections of plastic embedded material, make such embedding procedures the preferred method for the processing of bone marrow trephine biopsy specimens.

Antibodies, Monoclonal↗
PubMed1988

Surface spectroscopic characterization of titanium implants after separation from plastic-embedded tissue.

The method of plastic embedding of tissue and implant and subsequent separation of plastic and implant for preparing sections of tissue adjacent to solid metallic implants relies on a successful separation of the embedment and the implant. In this work, the surface of machined Ti implants has been analysed in order to investigate to what extent plastic remnants exist on the implant after separation. SEM and AES analyses show that at least 70% of the implant surface is free of plastic remnants to a proximity of 10 nm or less from the implant surface. The method is simple and suitable for both light and transmission electron microscopy of the interface tissue.

Bone Screws↗
PubMed1979

Staining calcified tissues in plastic embedding medium.

Two procedures for staining sections of calcified teeth and/or bone embedded in plastic without dissolving the embedding medium were developed to study early bone regeneration in proximity to carbon implants in monkey alveolar bone and tissue degeneration in pathological human bone. These procedures allow differential staining of delicate bone tissues and prevent breakage of sections because the supporting plastic does not have to be removed.

Animals↗
PubMed1989

A comparative study of morphometric measurements of nucleoli in uveal melanomas from electron micrographs and plastic-embedded and paraffin-embedded sections.

Morphometric measurements of nucleoli were done on uveal melanomas from surviving and nonsurviving patients. The melanomas were embedded in paraffin and plastic, and measurement data from Papanicolaou-stained paraffin-embedded sections, toluidine blue-stained plastic-embedded sections and scanning transmission electron micrographs (STEM) of plastic-embedded sections were compared. The results showed that one parameter, the coefficient of variation (CV) of nucleolar area, correctly classified 80% of the cases as to survival when plastic-embedded material was used and 70% of the cases when paraffin-embedded material or STEM micrographs were used. The inverse standard deviation of the nucleolar area was a better predictor of outcome than was the CV of nucleolar area only in the paraffin-embedded sections. The nucleolar measurements were most easily and rapidly performed in the plastic-embedded sections.

Humans↗
PubMed1995

A comparison between the effects of paraffin and plastic embedding of the normal and obstructed minipig detrusor muscle using the optical dissector.

PURPOSE: The purpose of this study was to estimate the relative shrinkage of the normal, obstructed and recovery minipig urinary bladder by comparing tissues from the same bladders embedded in paraffin or plastic. MATERIALS AND METHODS: Optical dissectors were used to make nucleus numerical density estimates in thick paraffin and plastic sections from the same bladder. The ratio of the 2 numerical densities depends only on differences in tissue shrinkage. In 9 minipigs a partial bladder outlet obstruction was created by implanting a 6 to 7 mm. Teflon ring around the proximal urethra. After an obstruction period (median 63 days) the ring was removed and after a recovery period (median 60 days) the animals were sacrificed. Biopsies were taken prior to obstruction, at removal of obstruction, and after recovery and were processed for paraffin and plastic sections to evaluate relative shrinkage. Two control pigs were sham-operated and biopsies taken at the same 3 time points. RESULTS: The optical dissector method was found to be an easy way to estimate the relative shrinkage of paraffin-embedded bladder tissue in proportion to plastic-embedded tissue. Both in human and minipig bladders, paraffin embedding caused a relative shrinkage of about 30% in proportion to plastic embedding. Both the obstructed and recovery detrusor muscles responded to embedding by either method in a manner indistinguishable from the normal bladder. CONCLUSION: When dealing with stereological evaluation of the detrusor muscle, the relative shrinkage of the embedded normal, obstructed and recovery bladder tissue can be ignored.

Animals↗
PubMed1994

Detection of monoclonal B-cell populations in decalcified, plastic-embedded bone marrow biopsies with the polymerase chain reaction.

Polymerase chain reaction (PCR) has been employed successfully for the detection of clonal immunoglobulin gene rearrangements in paraffin-embedded clinical samples. The authors examined whether this technique can also be applied to fixed, decalcified, and plastic-embedded bone marrow biopsies. DNA extracted from 66 glycolmethacrylate-embedded trephine biopsy samples was amplified for the detection of rearranged VDJ regions of the immunoglobulin heavy chain genes using both a single-step and a semi-nested PCR technique. After exclusion of samples with inadequate DNA, clonality was confirmed in 16 (67%) of 24 cases with B cell malignancy, whereas all 11 non-B cell neoplasms, and 6 of 9 cases with normal bone marrow showed evidence of a polyclonal B cell population. Patterns indicating oligo- or monoclonality were observed in three plastic-embedded samples of normal bone marrow, although control PCR of frozen bone marrow samples obtained in parallel showed no evidence of clonality. Repeated PCR of these cases revealed inconsistent bands, probably due to the amplification of rare templates from polyclonal B cells. Decalcified, plastic-embedded bone marrow biopsies are suitable for PCR-based determination of B-cell clonality. To exclude the possibility of false-positive results, monitoring of template DNA quality and independent control amplifications are mandatory.

B-Lymphocytes↗
PubMed1992

Simultaneous assessment of TGFB and cell cycle kinetics using IUdR/BrdU infusions in human neoplasms from plastic-embedded tissue.

We describe an immunohistochemical technique that makes use of two monoclonal antibodies (MAb), one to detect the transforming growth factor B (TGFB) and another that reacts with iodo- and bromodeoxyuridine. The purpose of this technique is to determine the relationship between TGFB expression and the S-phase cells in human tumors. Since both can be distinctly identified in situ from tissue embedded in plastic, in assessment of the geographic orientation of S-phase cells in relation to such factors as TGFB, contiguity to blood vessels, nerve fibers, and macrophages can also be achieved.

Antibodies, Monoclonal↗
PubMedDate not supplied

Plastic embedding of avian tissues for diagnostic histopathology.

A series of photomicrographs show the histologic features of avian tissues embedded in plastic and sectioned on glass knives. The techniques described gave superior resolution, less cell shrinkage, and fewer sectioning artifacts than sections prepared with conventional paraffin methods.

Acrylates↗
PubMed1992

Prediction of various grades of cervical neoplasia on plastic-embedded cytobrush samples. Discriminant analysis with qualitative and quantitative predictors.

The purpose of this study was to investigate whether discrimination into five groups of various grades of cervical preneoplasia and neoplasia is possible using discriminant analysis models. Data were analyzed for 242 cases diagnosed as either slight dysplasia (n = 50), moderate dysplasia (n = 50), severe dysplasia (n = 50), carcinoma in situ (n = 50) or invasive carcinoma (n = 42) and consisted of qualitative and quantitative features of cells derived from a repeat sample taken from the ectocervix as well as the endocervix using Cytobrushes. The samples were embedded in plastic, and thin sections were prepared, resulting in a monolayer of cut nuclei. The percentages of expected correct prediction were obtained by using 10,000 double cross-validation samples; the mean percentage of correct prediction into five groups using cross-validation was 65% (in the original analysis, 72%) and into two groups (dysplasia versus carcinoma in situ and invasive carcinoma) was 91% (93%). The results reflect group discrimination potential; we do not claim reliability of prediction for an individual patient. The patients were not a representative sample of the population; to investigate whether groups of patients could be discriminated on the basis of both qualitative and quantitative features, the data analyzed contain an almost equal number of observations in each of the five groups. The results indicate that features do not classify the cases in the same way; the discriminant analyses suggest that quantitative features play an important role in the discrimination of dysplasia from carcinoma cases, while the majority of the qualitative features are important in discrimination within the three dysplasia groups.

Biopsy↗
PubMed1982

Improved handling of embedding plastics for electron microscopy.

An improved, safer, rapid method for preparing embedding plastics for electron microscopy is described. The method consists of contained storage and dispensing of individual plastic components on an automatic tare balance. The proportions are based on weight measurements and may be calculated from volume or proportion recipes. The usual problems in and resulting from embedding plastic handling have been eliminated.

Animals↗
PubMed1983

Cryoultramicrotomy versus plastic embedding: comparative immunocytochemistry of rat anterior pituitary cells.

The anterior pituitary of the rat is used as a model for the study of the effects of freezing or plastic embedding on the maintenance of antigenicity. Rat anterior pituitaries are fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer pH 7.4. Some of the blocks are post-fixed before being divided into two lots. One batch is frozen, while the other is dehydrated and embedded. The indirect antibody enzyme method is applied to ultrathin sections obtained by cryoultramicrotomy after freezing or by sectioning after embedding. All six pituitary hormones are detected by both methods. Comparison shows that the morphological characteristics are identical for both techniques, though ultrastructural preservation is better after embedding. Immunoreactivity is found in secretory granules and sometimes in the endoplasmic reticulum. Osmium postfixation may reduce or even abolish antigenicity in plastic-embedded tissue. After cryoultramicrotomy, however, even after osmium fixation, antibody may be used 1000 times more diluted than after plastic embedding. Embedding preserves ultrastructure and limited antigenicity while the use of cryoultramicrotomy is a far more sensitive technique.

Adrenocorticotropic Hormone↗
PubMed1986

Immunohistochemical demonstration of DNA-incorporated 5-bromodeoxyuridine in frozen and plastic embedded sections.

The application of an immunohistochemical method in the detection of replicating cells, that have incorporated 5-bromodeoxyuridine (BrdUrd), was studied on frozen and plastic embedded sections of different rat tissues. Hydrolysis conditions employed in the Feulgen procedure are essential in making the incorporated BrdUrd accessible to the monoclonal anti-BrdUrd antibodies. To demonstrate the incorporated BrdUrd in plastic embedded sections a subsequent etching with xylene and digestion with protease is necessary. Data obtained with this method are completely comparable with those found by the tritiated thymidine method. In comparison with the thymidine method, the BrdUrd method is much less time consuming and does not require precautions in working with radioactivity. The BrdUrd-method enables a more precise localization as is especially shown in the plastic embedded sections.

Animals↗
PubMed1985

A comparison of subcellular element concentrations in frozen-dried, plastic-embedded, dry-cut sections and frozen-dried cryosections.

Biological X-ray microanalysis of diffusible elements within cellular and subcellular compartments requires preparation methods to retain electrolytes in the compartments they occupied in vivo. X-ray microanalysis of frozen-dried, plastic-embedded samples has been used to quantitate electrolytes at the cellular level. We have compared the subcellular elemental distribution in dry cut sections from such samples with that in ultrathin frozen-dried cryosections. Rat pancreases were quench-frozen onto a helium-vapor-cooled copper block. Cryosections were cut at 130-150 K, transferred using a Gatan cold stage, frozen-dried in the column and analysed at 190 K. Tissue fragments were frozen-dried at 190 K, and cut on a dry knife at 293 K. Both samples provided images permitting unambiguous identification of all major compartments except the Golgi complex. Intracellular potassium-to-sodium ratios obtained on frozen-dried plastic-embedded sections were lower than for cryosections (e.g. 1.77 in basal cytoplasm in plastic sections as compared to 4.34 for cryosections) and varied with the pre-embedding procedure (e.g. 1.77 in formaldehyde-fixed as compared to 2.87 in osmium-fixed plastic sections). Potassium gradients between adjacent organelles were large in cryosections and insignificant in plastic-embedded material. Higher cytoplasmic phosphorus, potassium and sulfur concentrations were observed in cryosections. Therefore, a redistribution of electrolytes and covalently bound elements occurred subcellularly in the plastic sections. Calcium was quantifiable in most organelles in cryosections but the plastic lowered sensitivity too much to permit routine calcium quantification. We conclude that in our hands frozen-dried, plastic-embedded samples were compromised and provided lower sensitivity than cryosections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Plastic-embedded semi-thin sections of fine needle aspiration biopsies with dibasic staining. Diagnostic and didactic applications.

The diagnostic and didactic utility of plastic-embedded semi-thin sections of fine needle aspiration biopsies is presented using a case-study approach. The Spurr epoxy semi-thin sections were stained with a newly developed sequential basic fuchsin-methylene blue stain, which gives hematoxylin-and-eosin-like staining and simultaneously substitutes for a wide variety of special stains. The informational content of the sections can approach that of electron microscopy. The use of a direct off-the-slide "pop-off" technique in preparing the plastic-embedded sections allows for a direct comparison between similar groups of cells embedded in plastic and present on the routine aspiration slides; retrospective analysis can discern subtle, previously unrecognized morphologic features in the alcohol-fixed, Papanicolaou-stained slides. The limitations of this comparative approach, however, become manifest when the effects of alcohol fixation on cells are directly compared in plastic and at the ultrastructural level to aldehyde fixation.

Adenoma↗
PubMed1984

Spontaneous autoradiographic grain activation associated with mast cells in methacrylate plastic embedded tissue sections.

Autoradiographic tracing using tritium labeled compounds or cells is a common laboratory technique for light and electron microscopy. This report describes a chemographic effect associated with certain cells in sections from tissues embedded in the new methacrylate plastic embedding compounds. When tissue sections from rats and rhesus monkeys that received no radioisotope were coated with nuclear track emulsion and subsequently developed, cells with morphologic characteristics of mast cells showed significant grain formation over the entire cell. Three different types of methacrylate plastics were tested using rat and monkey tissues and all three were found to promote grain formation over mast cells; however, this phenomenon was not seen in similar tissue sections from paraffin or epoxy embedded material. The properties of methacrylate plastics which promote positive chemography by mast cells may reflect the greater permeability of this class of plastics. Due to their wide tissue distribution, the presence of such chemographically active cells could cause false estimates of the distribution of either exogenous radiolabeled cells or radioisotopes within many tissues.

Animals↗