SEARCH · PubMed Health

Results for “Paraffin Embedding”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed1991

Distribution and pattern of expression of villin, a gastrointestinal-associated cytoskeletal protein, in human carcinomas: a study employing paraffin-embedded tissue.

Villin is a 95-kilodalton gastrointestinal-related cytoskeletal protein associated with axial microfilament bundles of brush border microvilli. We tested the hypothesis that expression of this protein was restricted to adenocarcinomas of gastrointestinal origin in a retrospective study of 203 human neoplasm that had been fixed in Carnoy's or methacarn fixative and embedded in paraffin. Villin expression was restricted to a subset of epithelial tumors, with no expression noted in any cases of sarcoma, melanoma, or lymphoma. Villin proved to be a very sensitive and relatively specific marker of gastrointestinal adenocarcinomas: all colonic, gastric, and pancreatic carcinomas were positive, and none of the breast or lung carcinomas were positive, with the single exception of a bronchioalveolar adenocarcinoma. However, a subset of nongastrointestinal adenocarcinomas, including some adenocarcinomas of ovary, endometrium, and kidney, were also positive. Nonetheless, at least three distinct patterns of villin expression were discerned, some of which were quite specific for individual tumor types. Thus, an apical or brush border pattern of villin expression was seen in virtually all gastrointestinal adenocarcinomas, as well as in the occasional villin-positive endometrial or ovarian adenocarcinomas. A membranous distribution of carcinomas, mimicked the patterns of the normal counterpart tissue, e.g., delineation of bile canalicular structures. Finally, no relationship was found between the presence, or pattern of expression, of villin and the state of tumor differentiation. It is concluded that antibodies to villin may play an important role in immunocytochemical analyses of poorly differentiated malignant tumors in appropriately fixed, paraffin-embedded tissue and in cases where the primary site is indeterminant from clinical history and histology.

Adenocarcinoma↗

PubMedDate not supplied

Microwave stabilization versus chemical fixation. A morphometric study in glycolmethacrylate- and paraffin-embedded tissue.

A morphological and morphometrical study was performed on testicular cells after microwave stabilization of the tissue while immersed in phosphate buffered saline (PBS), 0.9 NaCl or Tris-HCl. Fixation in Carnoy's fluid without irradiation was chosen as a control chemical fixation method. After microwave stabilization or chemical fixation, the testes were embedded in paraffin or in plastic (glycolmethacrylate). An excellent morphology, comparable to that after chemical fixation in Carnoy's fluid, was observed in the plastic sections of tissue irradiated in PBS or NaCl, even when the sections were subsequently treated with an aggressive reagent at high temperature, required for the Feulgen reaction. The nuclear area of the microwave-stabilized Sertoli cells was 37-46% smaller in haematoxylin-eosin stained, paraffin sections in comparison with that in the glycolmethacrylate sections. The microwave-stabilized, paraffin-embedded tissue was much more vulnerable to the hot HCl treatment of the Feulgen staining than the chemically fixed tissue, resulting in an additional 10-20% decrease in nuclear size. The latter finding is particularly important for quantitative microscopy, where the Feulgen staining method is often employed.

Animals↗

PubMed1996

Immunohistochemistry of transmissible gastroenteritis virus antigens in fixed paraffin-embedded tissues.

An immunohistochemistry technique was developed using fixed tissues to study the presence and location of transmissible gastroenteritis virus (TGEV) antigens in situ. Experimentally infected gnotobiotic and conventional pigs as well as pigs with natural TGEV infection were examined. The staining technique was based on detection of the major structural protein of TGEV, the nucleocapsid, by using a pool of 3 monoclonal antibodies. Formalin and periodate-lysine-paraformaldehyde (PLP)-fixed intestinal tissues from a gnotobiotic pig inoculated with virulent TGEV were used to determine optimal antibody concentrations and incubation times. The intestinal tissues remained in their respective fixatives for 6 months, and serial sections were removed at sequential times and embedded in paraffin blocks. PLP and 10% neutral buffered formalin were acceptable fixatives and preserved TGEV nucleocapsid antigenicity for up to 6 months. Formalin, in comparison with PLP as a fixative, was better for preserving original tissue morphology and provided better antigen detection. Conventional crossbred pigs were inoculated with virulent TGEV, and animals were euthanized on various postexposure days. Intestinal tissues were positive for TGEV nucleocapsid antigens on postexposure days 2, 4, and 8. The immunohistochemistry technique detected TGEV antigen in stored paraffin-embedded tissues from 14 naturally infected pigs previously confirmed as positive for TGEV using a direct immunofluorescence assay on intestinal mucosal smears, whereas 9 naturally infected pigs confirmed negative for TGEV antigen by the same immunofluorescence assay showed no staining consistent with the presence of TGEV antigen. Immunohistochemistry provides a method to detect TGEV and possibly other closely related coronaviruses such as porcine respiratory coronavirus in situ. A diagnostic test using the same fixed tissues processed for histopathology provides veterinary practitioners an alternative to delivering live pigs or refrigerated fresh intestinal samples containing infectious virus to a diagnostic laboratory. Investigators can utilize this technique to retrospectively screen fixed tissues for TGEV antigen.

Animals↗

PubMed1981

Glial fibrillary acidic protein in the optic nerve of the developing albino rat: an immunoperoxidase study of paraffin-embedded tissue.

The unlabeled peroxidase-anti-peroxidase method was used to stain glial fibrillary acidic (GFA) protein in the optic nerve of the developing albino rat. Optic nerves from animals ranging in age from the day of birth to adulthood were embedded in paraffin following fixation with various agents for times ranging from 30 minutes to 48 hours. GFA protein activity was demonstrable at birth in large astrocytic processes following fixation with alcohols or with Perfix for short intervals, but not with 4% or 2% buffered paraformaldehyde solutions. With increasing age, GFA protein could be demonstrated using higher aldehyde concentrations, longer fixation times, and longer paraffin embedding schedules. At all ages GFA protein activity was greater following treatment with nonaldehyde fixatives rather than those containing formaldehyde or glutaraldehyde. At birth the majority of GFA protein-containing processes were confined to planes which were perpendicular to the axons of the optic nerve. With increasing age, tangential and longitudinal processes became more numerous until, in the mature optic nerve, astrocytic processes were best characterized as being multidirectional.

Aging↗

PubMed1981

"Pop-off" technic. The ultrastructure of paraffin-embedded sections.

Stained paraffin embedded sections sometimes contain a precise area that warrants further investigation at an ultrastructural level. A technic is described whereby an area in question may be reembedded into plastic and sectioned for examination under the electron microscope. The decoverslipped paraffin section is "popped-off" into an inverted BEEM capsule. Suspected viral inclusions in sections may be identified or ruled out with this technic. Special stains, especially heavy metal applications, not able to be utilized in conventional plastic embedding may be reembedded into plastic. The metallic granules may be visualized ultrastructurally without further grid staining. This method is especially helpful for cell smears and cell monolayers since they may be the only material available for study. Although ultrastructural detail is often poor, one does have the ability to study the identical section under both the light and the electron microscopes.

Glomerulonephritis↗

PubMed1978

Immunofluorescence studies of canine distemper encephalitis on paraffin-embedded tissue.

A paraffin-embedding technique for fluorescent antibody studies of canine distemper encephalitis was developed. Specific fluorescence was demonstrated in all brain tissue from dogs with canine distemper, and when compared with tissue on cryostat sections, the paraffin-embedded tissue showed superior preservation of tissue architecture. The preservation of viral antigen was good, and the appearance of fluorescence in gray- and white-matter lesions was described. In gray matter, extensive fluorescence was found mainly in neurons; fluorescence in white matter was less extensive and was mainly associated with astrocytes.

Animals↗

PubMed1979

Histochemical demonstration of enzyme activities in plastic and paraffin embedded tissue sections.

Histochemical staining for enzymes is usually performed on frozen sections. This report lists the longer incubation times required to demonstrate esterase, acid phosphatase, beta-galactosidase, and cytochrome oxidase in plastic embedded and ruotine paraffin embedded tissues. The sections embedded in plastic, i.e. water soluble methacrylate (Polyscience's JB-4) and cut at 2 micrometers, were far superior to frozen sections and paraffin embedded sections both in tissue detail and in the localization of the histochemical reaction product.

Acid Phosphatase↗

PubMed1990

Analysis of leukocyte surface antigens on ethanol-fixed paraffin-embedded tissue material.

Ethanol-fixed paraffin-embedded specimens of human tissues were studied whether the surface antigens of leukocytes in these tissues can be stained and analyzed. Three-layer indirect immunoperoxidase staining was performed on the ethanol-fixed paraffin-embedded sections by the use of several monoclonal antibodies for whole human leukocytes (Dako LC), B cells (Dako CD-22, 4KB5, and L26; Leu 14), T cells and their subsets (Dako UCHL-1, T1, T3, T4 and T8; Leu 4, 3a and 2a) and monocyte/macrophage lineage (Dako macrophage, Leu M1, M3 and M5). The results were compared with those on fresh-frozen sections. No essential differences were obtained between the paraffin-embedded and the fresh frozen sections stained by the following antibodies; Dako LC for whole human leukocytes; Dako UCHL-1, T3 and Leu 4 for T cells; Dako CD22, 4KB5, L26 and Leu 14 for B cells; Dako macrophage, Leu M1 and M5 for monocyte/macrophage lineage. On the other hand, the subsets of T cells could only be detected on the fresh-frozen sections. The results of the leukocyte analysis on the paraffin-embedded specimens of several renal diseases were very similar to those reported by other investigators on fresh-frozen sections or PLP-fixed materials. Thus, by the use of appropriate monoclonal antibodies, the ethanol-fixed paraffin-embedded material can be used for leukocyte analysis except for the definition of T cell subsets.

Antibodies, Monoclonal↗

PubMed2004

Effect of formalin, acetone, and RNAlater fixatives on tissue preservation and different size amplicons by real-time PCR from paraffin-embedded tissue.

RNA recovered from paraffin-embedded tissue has been reported to be a suitable substrate for polymerase chain reaction. During tissue fixation and paraffin embedding, RNA undergoes degradation, but with certain restrictions, it can be used for gene expression studies. At the same time, formalin-fixed, paraffin embedded histopathology archives contain an unestimable collection, which could be analyzed to investigate changes in mRNA expression in pathologic processes. To decide for future tissue conservation of pathology samples, it would be reasonable to satisfy both histologic and molecular biologic needs. The effect of three different fixation methods, RNAlater (SIGMA R 0901, St Louis, MO), acetone, and formalin, were compared by histology, immunohistochemistry, and real-time PCR. To assess tissue structure preservation and antigenicity, hematoxylin-eosin staining and immunohistochemistry were performed; to assess RNA quality, RNA was extracted and the transcription of different amplicon sizes (121, 225, 406 bp for GAPDH; 166, 310, 536 bp for beta globin) were examined on human endometrium samples. The most adequate tissue preservation was found in case of formalin fixation, while there were no significant differences in the three fixatives' yields for various size real-time PCR amplicons. Longer amplicons (above approximately 225 bp) have limited use for gene expression studies, while shorter amplicons could give more reliable results.

Adult↗

PubMed1997

Staining paraffin embedded sections of scald of barley before paraffin removal.

Staining of paraffin embedded sections with periodic acid-Schiff reagent and fast green before paraffin removal resulted in differentiation of barley seed and leaf tissue from fungal structures of Rhynchosporium secalis. Crystal violet, toluidine blue O and antiline blue also successfully stained fungal structures of R. secalis in barley leaf tissues. Staining of embedded sections before paraffin removal allows simple processing of a series of sections, saves time and reduces solvent consumption.

Aniline Compounds↗

PubMed1990

Improved flow cytometric determination of proliferative activity (S-phase fraction) from paraffin-embedded tissue.

Recent studies suggest that proliferative activity (S-phase fraction [SPF]) may have greater prognostic significance than total nuclear DNA content; however, relatively few studies have examined SPF from paraffin-embedded tissue because of significant contamination of histograms with debris. In this study, cell cycle analysis was performed on 124 matched tissue specimens. Fresh tissue was divided into two equal portions; one portion was frozen, whereas the other portion was processed and embedded in paraffin. S-phase could be determined for both frozen and paraffin-embedded tissue in 81 cases. Correlation between SPF from frozen and paraffin-embedded tissue was demonstrated (r = 0.80) when debris was subtracted from histograms with the use of two new subtraction algorithms referred to as multicut and singlecut. Unlike other debris-subtraction algorithms, the quantity and distribution of debris calculated by these algorithms are dependent on the magnitude and position of histogram peaks. A lesser degree of correlation was demonstrated with the use of a standard exponential debris subtraction algorithm (r = 0.67). Correlation of SPF for aneuploid cases was greater when SPF was calculated as a percentage of the aneuploid cell population rather than as a percentage of the entire cell population. This was attributed to the observation that the proportion of aneuploid cells from paraffin-embedded tissue was less than that from frozen tissue. The results of this study indicate that SPF can be calculated from paraffin-embedded tissue with values comparable to those obtained from frozen tissue. The ability to calculate SPF reliably from paraffin-embedded tissue should allow additional evaluation of this parameter as a prognostic indicator.

Algorithms↗

PubMed1999

[Histological study of early postmortem changes in various organs: comparison of the paraffin embedding method and the epoxy resin embedding method].

For the purpose of morphological assessment of the early postmortem interval, Wistar rats were killed by cervical dislocation and left at 23 degrees C for 1, 3, 5, 10, 15 and 24 hours. After a given postmortem interval, tissue samples taken from kidney, pancreas, liver, heart and skeletal muscle were embedded in paraffin or epoxy resin and examined by light microscopy. Specimens obtained from the paraffin block did not show a good correlation between histological changes and postmortem interval, because the postmortem changes continued during the fixation period. On the other hand, the time course of histological changes in specimens obtained from the epoxy block, particularly the development of clumping of nuclear chromatin and cytoplasmic vacuolation in each organ, reflected the postmortem interval because of the rapid fixation by glutaraldehyde. These histological changes were characteristic of each organ up to 24 hours after death. In addition, the semithin epoxy resin section made high-resolution light microscopy possible. Therefore, the epoxy resin embedding method is superior to the paraffin embedding method for the purpose of estimation of the time of death. The morphological changes characterising time after death are as follows: at 1 hour after death, cytoplasmic vacuolization and slight clumping of nuclear chromatin in pancreatic acinar cells; at 3 hours after death, slight clumping of nuclear chromatin in distal tubules, cytoplasmic vacuolization in skeletal muscle, and edema in cardiac muscle; at 5 hours after death, clumping of nuclear chromatin in proximal tubules as well as distal tubules, and cytoplasmic vacuolization in hepatocytes; at 10 hours after death, edema in proximal tubules, condensation of nuclear chromatin (apoptosis) and edema in distal tubules, and atrophy of acinar cells in the pancreas; at 15 hours after death, cytolysis of distal tubules; at 24 hours after death, cytolysis of hepatocytes and clumping of chromatin in skeletal muscle. Thus we can conclude that the time course of histological changes is useful for the estimation of postmortem interval.

Animals↗

PubMed1992

Cryofixed, freeze-dried and paraffin-embedded skin enables successful immunohistochemical staining of skin basement membrane antigens.

Conventional chemical fixation and paraffin-embedding procedures give good preservation of morphology, although the antigenicity of many proteins in the tissue sample is destroyed. On the other hand, fresh frozen sections can preserve the antigenicity, but provide poor morphological preservation. To overcome this dilemma, cryofixation and freeze drying were used on human skin tissue, applying methodology which has only been used to study lymphoid tissue. First, fresh human skin was cryofixed in liquid isopentane (-160 degrees C) cooled by liquid nitrogen. The skin was then freeze-dried at -40 degrees C and 10(-2) atmospheric pressure for 72 h, followed by embedding in paraffin. Sections 4 microns thick taken from this cryofixed, freeze-dried, and paraffin-embedded skin were stained with hematoxylin-eosin or used for immunolabeling with antibodies against basement membrane antigen, including type IV and type VII collagen, bullous pemphigoid antigen, epidermolysis bullosa acquisita antigen, and GB3 antigen. The morphological preservation of these sections was as good as that of routine formalin-fixed and paraffin-embedded skin sections. The basement membrane was clearly immunostained with all antibodies used, and the intensity of the reaction was as strong as that seen in frozen sections. Evaluation of antigen distribution in conjunction with the detailed skin structure was therefore possible in the same sections.

Antibodies, Monoclonal↗

PubMed2003

Comparison of methods for DNA extraction from paraffin-embedded tissues and buccal cells.

Both paraffin-embedded tissue specimens and buccal cells are excellent resources for large-scale molecular epidemiological studies. In order to identify the optimal method for DNA extraction, we compared three methods: (1) modified phenol-chloroform protocol; (2) simple boiling method; and (3) DNA Extraction Mini Kit. For paraffin-embedded tissue specimens, amplification of the beta-globin gene sequence was successful in 30 of 34 (88.2%) by the simple boiling method, 29 of 34 (85.3%) samples using DNA extracted by the phenol-chloroform method, and 18 of 34 (52.9%) by the DNA Mini Kit. For buccal cells, amplification of the beta-globin gene sequence was successful in 16 of 17 (94.1%) DNA samples extracted by the phenol-chloroform method, 2 of 16 (12.5%) by the simple boiling method, and 12 of 16 (75%) by the DNA Mini Kit. Both the simple boiling method and the phenol-chloroform method are better methods for DNA isolation from paraffin-embedded tissue specimens, and the phenol-chloroform method is the best method for DNA extraction from buccal cells.

Cheek↗

PubMed2001

Quantitative gene expression analysis in microdissected archival formalin-fixed and paraffin-embedded tumor tissue.

Formalin-fixed, paraffin-embedded tissue is the most widely available material for retrospective clinical studies. In combination with the potential of genomics, these tissues represent an invaluable resource for the elucidation of disease mechanisms and validation of differentially expressed genes as novel therapeutic targets or prognostic indicators. We describe here an approach that, in combination with laser-assisted microdissection allows quantitative gene expression analysis in formalin-fixed, paraffin-embedded archival tissue. Using an optimized RNA microscale extraction procedure in conjunction with real-time quantitative reverse transcriptase-polymerase chain reaction based on fluorogenic TaqMan methodology, we analyzed the expression of a panel of cancer-relevant genes, EGF-R, HER-2/neu, FGF-R4, p21/WAF1/Cip1, MDM2, and HPRT and PGK as controls. We demonstrate that expression level determinations from formalin-fixed, paraffin-embedded tissues are accurate and reproducible. Measurements were comparable to those obtained with matching fresh-frozen tissue and neither fixation grade nor time significantly affected the results. Laser microdissection studies with 5-microm thick sections and defined numbers of tumor cells demonstrated that reproducible quantitation of specific mRNAs can be achieved with only 50 cells. We applied our approach to HER-2/neu quantitative gene expression analysis in 54 microdissected tumor and nonneoplastic archival samples from patients with Barrett's esophageal adenocarcinoma and showed that the results matched those obtained in parallel by fluorescence in situ hybridization and immunohistochemistry. Thus, the combination of laser-assisted microdissection and real-time TaqMan reverse transcriptase-polymerase chain reaction opens new avenues for the investigation and clinical validation of gene expression changes in archival tissue specimens.

Animals↗

PubMed1997

Immunohistochemical detection of hog cholera viral glycoprotein 55 in paraffin-embedded tissues.

Formalin-fixed, paraffin embedded tissues obtained from 40 pigs inoculated with a field isolate of hog cholera virus were examined for the presence of Gp55, a major structural protein of the virus envelope, using a monoclonal antibody-based immunohistochemical test with the avidin-biotin-peroxidase complex method. Immunoreactivity was detected in hog cholera virus-infected tissues but not in control pigs tissues, African swine fever virus-infected tissues, or bovine viral diarrhea virus-infected porcine or bovine tissues. The first positive reactions were seen in lymphatic tissues, digestive tract and skin on postinoculation day (pid) 4, respiratory and urinary tissues on pid 5, nervous tissues on pid 6, and endocrine tissues on pid 7. These staining reactions persisted until the last observation on pid 18. Hog cholera virus antigen was not detected in heart tissue at any time. The highest levels of antigen detection were found in tonsils, spleen, and pancreas, although the esophageal mucosa and skin epithelial cells were also intensely and widely stained. The cellular staining pattern of Gp55 had a ubiquitous distribution. It was found in epithelial cells, macrophages and circulating monocytes, endothelial cells, lymphoid cells, and glial cells. The results showed a high specificity and high sensitivity for detecting hog cholera Gp55 in formalin-fixed, paraffin embedded tissue samples. This method allows precise association of Gp55 with specific cells, tissues, and histologic lesions, making the technique suitable for use in routine diagnosis of hog cholera.

Animals↗

PubMed1993

Immunohistochemical localization of cytokeratins in normal eccrine glands, with monoclonal antibodies in routinely processed, formalin-fixed, paraffin-embedded sections.

BACKGROUND: Immunohistochemical detection in paraffin sections would be of value in the retrospective analysis of formalin-fixed, paraffin-embedded tissues. OBJECTIVE AND METHODS: In this study with several monoclonal antibodies directed against fixation-resistant keratin antigens, we performed immunohistochemical staining on routine paraffin-embedded sections to localize specific keratins in the eccrine sweat glands and to determine the tissue distribution of various keratins. RESULTS: We clarified the localization of specific keratins in different segments of normal eccrine glands. Immunohistochemical localization of individual cytokeratins showed different patterns in secretory and ductal portions, although cytokeratins were expressed in all segments of normal sweat glands. Different immunoreactivities were noted in the luminal and basal cells of eccrine ducts. There were also some differences in immunophenotype between the acrosyringium and the dermal ducts. CONCLUSION: These data provide information for the determination of the histogenesis and differentiation of skin tumors with eccrine differentiation.

Antibodies, Monoclonal↗

PubMed1995

Interphase cytogenetics of gastric carcinoma: fluorescence in situ hybridization (FISH) applied to cells obtained from formalin-fixed paraffin-embedded tissues.

The interphase cytogenetics in formalin-fixed and paraffin-embedded gastric cancer tissues were examined by fluorescence in situ hybridization (FISH) with alpha-satellite DNA probes. Two gastric carcinoma cell lines, TMK-1 and MKN-28, were first analyzed cytogenetically. Of 25 TMK-1 cell karyotypes, chromosome 7 showed trisomy and chromosome 17 showed disomy in 18 cells. Most MKN-28 cells showed disomy of both chromosomes 7 and 17. Suspensions of singly isolated TMK-1 and MKN-7 cells were obtained from the cultured cells, and from paraffin-embedded tissue specimens fixed with formalin for 0, 1, 3 and 5 days obtained from xenotransplanted tumors in nude mice. The numbers of chromosomes 7 and 17 analyzed with the karyotypic preparations coincided well with those determined by FISH, even in the paraffin-embedded specimens. The number of tumor cells showing no signals, however, increased in the specimens after 5 days formalin fixation. In 10 surgically removed gastric carcinomas, the predominant signal number for chromosomes 7 and 17 in the cells of paraffin-embedded tissues was two (disomy), except in one papillary carcinoma, which was trisomic for chromosome 7. Large subpopulations (more than 20%) showing trisomy were found in four cases for chromosome 7 and in five cases for chromosome 17. A higher frequency of trisomy was found in well differentiated than in poorly differentiated carcinomas. These findings suggest that the FISH technique is a useful tool for detecting chromosomal aberrations in gastric adenocarcinoma cells, even in paraffin-embedded specimens, as long as the tissues are fixed with formalin for an appropriate time.

Adenocarcinoma↗