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At least 343 records · Page 19Linked to original sources
PubMed1997

The effect of fixation type on DNA extracted from paraffin-embedded tissue for PCR studies in dermatopathology.

BACKGROUND: Amplification of nucleic acids from paraffin-embedded material by the polymerase chain reaction (PCR) is widely used to detect viral genomes, clonal gene rearrangements and oncogene mutations in skin specimens. Fixation with embedding of skin tissue is a procedure that has a profound effect on its molecular arrangement. OBJECTIVE: The aim of this study was to determine the effect of different fixatives on the PCR amplification of DNA. METHODS: We fixed randomly chosen fresh pathologic skin specimens in formalin, ethanol and Histochoice for 24 and 72 h and then embedded the tissue in paraffin. DNA was extracted from the paraffin-embedded tissues and used as template for amplification, producing 530- and 760-bp fragments of the phosphoglycerokinase gene. RESULTS: Our results indicate that PCR can be performed with excellent results on ethanol- and Histochoice-fixed, paraffin-embedded skin tissue with a rate of success comparable to that using fresh tissues; formalin-fixed tissue gave slightly less satisfactory results. CONCLUSION: This investigation corroborates previous reports investigating the effect of ethanol and formalin fixation on DNA amplification by PCR. Moreover, this is the first study showing that DNA extracted from tissue fixed with Histochoice is suitable for PCR gene amplification.

Base Sequence↗
PubMed1997

Detection of integrins in formalin-fixed, paraffin-embedded tissues.

Integrins are heterodimeric transmembrane receptors, which are expressed in many cells. In vitro experiments have demonstrated that integrins may be important in tumor progression and organ development. The functions of integrins were previously studied in cell cultures and their tissue expression was detected by immunofluorescence or immunoperoxidase in frozen sections. The purpose of this study was to determine the optimal conditions for detection of integrins in formalin-fixed, paraffin-embedded tissues. We utilized microwave heating and enzyme digestion in routinely processed, surgically removed tissues. Our results demonstrate that integrins can be reliably detected in archival material. This approach will facilitate further investigation of the role played by integrins in human malignancies and in developmental processes.

Formaldehyde↗
PubMed1984

Influence of decalcifying agents on immunoreactivity of formalin-fixed, paraffin-embedded tissue.

The influence of eight decalcifying agents on the immunoreactivity of formalin-fixed, paraffin-embedded tissue for immunoglobulins, lysozyme, factor VIII-related antigen and keratin was studied using the unlabelled antibody peroxidase-antiperoxidase (PAP) method. Limited studies were also performed on tissues fixed in acid-formalin mixtures. All tissues were stained using an indirect immunoperoxidase method with mouse monoclonal antibodies to IgM, kappa and lambda light chains. The results suggest that, with controlled trypsinization of sections, it was possible to obtain optimal immunostaining for all tested antigens, with adequate preservation of histological structure, after decalcification in neutral EDTA or 10% aqueous acetic or formic acid. Tissue treated with agents containing mineral acids exhibited variable immunoreactivity and impaired counterstaining.

Animals↗
PubMed1982

Nonspecific esterase activity in plastic-embedded tissues using Meldola Blue.

A method for the demonstration of nonspecific esterase activity in plastic-embedded tissues using Meldola Blue is described. Although Meldola Blue does not function as an electron carrier in this method, it may account for the short incubation time and excellent localization of the reaction product. Use of Meldola Blue is an advancement in the demonstration of enzyme activity in plastic sections.

Carboxylesterase↗
PubMed1999

Development of a polyclonal-antibody-based immunohistochemical method for the detection of type 2 porcine circovirus in formalin-fixed, paraffin-embedded tissue.

An immunohistochemical method for the detection of type 2 porcine circovirus (PCV2) in paraffin-embedded tissue was developed. Rabbits were inoculated with purified PCV2 to obtain a polyclonal antiserum. Antiserum was applied to sections of porcine tissue that contained lesions consistent with postweaning multisystemic wasting syndrome and in which PCV2 genome had been demonstrated by in situ hybridization. In all cases (18/18), the density and distribution of positive cells detected by in situ hybridization or immunohistochemistry were identical. The immunohistochemical method is more rapid and less expensive than in situ hybridization and is thus more suitable for routine diagnostic use.

Animals↗
PubMed1983

A silver method for counterstaining plastic embedded tissue.

This report presents a method which can be used for counterstaining semithin sections of plastic embedded tissue. The sections are treated with a solution of silver lactate, followed by physical development. During the silver lactate treatment, silver ions are bound by various tissue components as metallic silver or silver sulfide. During physical development catalytic reduction of silver ions to metallic silver takes place where silver has been bound in the tissue, enlarging the silver deposits to microscopically visible dimensions. The amplified silver deposits give high contrast staining in yellow, brown and black suitable for both color and monochrome photography. The localization of the silver deposits is highly specific and may reflect several independent chemical processes. Examples in several tissues are shown.

Animals↗
PubMed1997

Detection of serum amyloid A-derived proteins in formalin-fixed paraffin-embedded tissues: reliability of the method and expansion of its spectrum.

To further assess the reliability of the Shtrasburg method for detection of amyloid A in formalin-fixed, paraffin-embedded tissues and to expand the spectrum of the amyloid proteins analyzed by this method, we studied formalin-fixed, paraffin-embedded amyloid-containing tissues obtained from patients with the following types of amyloidosis: amyloid A, light chain, transthyretin, calcitonin, beta2 microglobulin, and senile seminal vesicle. The tissue samples were deparaffinized, processed, and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Western blot technique. Only specimens from patients with amyloid A amyloidosis gave protein bands: a single 8.5-kd band in lanes of all tissues studied, except thyroid tissue, which displayed two bands of about 5 and 10 kd. Other types of amyloid failed to show any protein band. These findings suggest that the Shtrasburg method is sensitive, specific, and reliable and may have an important role in the diagnosis of amyloidosis.

Amyloidosis↗
PubMed1992

Preparation and use of a monoclonal antibody to detect Chlamydia psittaci antigen in paraffin-embedded tissue sections.

A murine monoclonal antibody prepared against an ovine abortion isolate of Chlamydia psittaci (A22/Teramo) revealed specific binding to a 57 kDa chlamydial antigen in immunoblotting studies. The monoclonal antibody was able to detect intracytoplasmic chlamydial inclusions and scattered elementary bodies in infected McCoy cell culture, and on formalin-fixed paraffin-embedded tissue sections both from experimentally infected mice and from fetal membranes of cases of ovine enzootic abortion.

Animals↗
PubMed1993

Detection of p53 overexpression in routinely paraffin-embedded tissue of human carcinomas using a novel target unmasking fluid.

With the aid of a newly developed target unmasking fluid (TUF), p53 overexpression was visualized by immunohistochemistry on recent and archival paraffin-embedded tissue samples of colon, stomach, and pancreas neoplasms. Using monoclonal anti-p53 antibody pAb1801 as well as polyclonal antiserum to p53 CM1, TUF-mediated immunohistochemistry was fully concordant for p53 overexpression in paraffin-embedded carcinoma samples compared with freshly frozen tissue from the same tumors. Thus, prognostic and diagnostic assessment of p53 overexpression in malignant tissue, routinely fixed in formalin and embedded in paraffin wax, by TUF-mediated immunohistochemistry with monoclonal and polyclonal antibodies may be adopted as a new tool in diagnostic and research histopathology.

Antibodies↗
PubMed2002

Detection of bladder cancer by multitarget multicolour FISH: comparative analysis on archival cytology and paraffin-embedded tissue.

Detection of bladder cancer by multitarget multicolour FISH: comparative analysis on archival cytology and paraffin-embedded tissue We have evaluated the possibility of using the same specimen for both cytological diagnosis and multitarget multicolour FISH (MtMcFISH) analysis in order to determine whether the routinely processed specimens used for diagnosis were also suitable for this ancillary procedure. For this purpose 18 positive samples (11 voided urine and seven bladder washings) were selected, together with a representative section of the corresponding immediately previous or subsequent histological specimens. Two negative cytology slides were added as negative controls. FISH analysis revealed a normal pattern for each probe in the two negative controls and an abnormal pattern in the 18 positive cases. In the latter the same FISH alterations were found in the cytology samples and in the corresponding histological sections, and superimposable cytological/histological features were observed in two cases where two different histology samples were analyzed. The results clearly show that MtMcFISH may be successfully applied to destained routinely processed cytology slides.

Carcinoma, Transitional Cell↗
PubMed1984

A histochemical method for demonstrating papilloma virus infection in paraffin-embedded tissue.

In order to study the location of cells infected with human papilloma virus in paraffin-embedded tissues, the authors developed the following stain. Tissue sections were digested overnight with 0.01% deoxyribonuclease and then stained using the Feulgen stain with a light green counterstain. Cellular DNA was degraded, but viral DNA was not. Thus infected cells retained magneta nuclei, while uninfected cells stained a homogenous green. The stain was positive in 5/5 plantar warts, 7/8 verruca vulgaris, 2/2 laryngeal papilloma, and 18/20 condylomata accuminata. As a comparison, the indirect immunoperoxidase method on the same tissues stained 5/5 plantar warts, 6/8 verruca vulgaris, 0/2 laryngeal warts, and 2/20 condylomata accuminata. The presence of virus was confirmed by electron microscopic examination on one of the sections. Molluscum contageosum infected tissue also stained positively, but tissues infected with cytomegalovirus and herpes simplex virus did not. The only nonviral positive staining occurred with smears of sperm. The reasons for these results are discussed.

Animals↗
PubMed1982

Specificity and sensitivity of immunohistochemical detection of factor VIII/von Willebrand factor antigen in formalin-fixed paraffin-embedded tissue.

The immunohistochemical detection of factor VIII/von Willebrand factor antigen (FVIII/vWF-AG) in formalin-fixed paraffin-embedded tissues was investigated using the peroxidase-antiperoxidase (PAP) method. Highly purified human FVIII/vWF was used to raise rabbit anti-FVIII/vWF-AG serum. In addition to anti-FVIII/vWF-AG activity, the unabsorbed antiserum had anti-IgG, anti-IgM, and anti-alpha2-macroglobulin specificities. Following exhaustive absorption with these proteins, the antiserum reacted monospecifically for FVIII/vWF-AG in immunodiffusion, immunoelectrophoresis, and PAP immunohistochemistry. Sections of normal tissues from six patients and a total of 43 neoplasms were examined. Treatment of the tissue sections with trypsin prior to application of the antiserum markedly increased the sensitivity of FVIII/vWF-AG detection. The positive staining for FVIII/vWF-AG was restricted to endothelial cells in both neoplastic and nonneoplastic tissue. In general, the hyperplastic endothelia in neoplastic and reactive tissues stained more intensely than those in normal tissues. Expression of FVIII/vWF-AG by nonendothelial neoplastic cells was not observed. FVIII/vWF-AG is a reliable marker for endothelial cells.

Blood Coagulation Factors↗
PubMed1991

Antigen retrieval in formalin-fixed, paraffin-embedded tissues: an enhancement method for immunohistochemical staining based on microwave oven heating of tissue sections.

We describe a new approach for retrieval of antigens from formalin-fixed, paraffin-embedded tissues and their subsequent staining by immunohistochemical techniques. This method of antigen retrieval is based on microwave heating of tissue sections attached to microscope slides to temperatures up to 100 degrees C in the presence of metal solutions. Among 52 monoclonal and polyclonal antibodies tested by this method, 39 antibodies demonstrated a significant increase in immunostaining, nine antibodies showed no change, and four antibodies showed reduced immunostaining. In particular, excellent immunostaining results were obtained with a monoclonal antibody to vimentin as well as several different keratin antibodies on routine formalin-fixed tissue sections after pre-treatment of the slides with this method. These results showed that after antigen retrieval: (a) enzyme predigestion of tissues could be omitted; (b) incubation times of primary antibodies could be significantly reduced, or dilutions of primary antibodies could be increased; (c) adequate staining could be achieved in long-term formalin-fixed tissues that failed to stain by conventional methods; and (d) certain antibodies which were typically unreactive with formalin-fixed tissues gave excellent staining.

Antibodies, Monoclonal↗
PubMed1993

Effect of fixation time and microwave oven heating time on retrieval of the Ki-67 antigen from paraffin-embedded tissue.

Microwave oven heating has been employed for retrieval of antigens from formalin-fixed, paraffin-embedded tissue for immunohistochemical staining. Recently, a Ki-67 equivalent murine monoclonal antibody was generated which can detect tumor proliferative activity in routinely processed tissue with microwave oven heating. We assessed the effect of fixation time (4, 24, or 48 hr) and microwave oven heating time (7, 14, 21, 28, 35, or 49 min) on retrieval of the Ki-67 antigen from tonsil tissue. Ki-67 staining was quantitated by image analysis. Owing to the heterogeneity of Ki-67 staining within and between germinal centers, we employed a measurement technique that averages staining across the germinal centers of each section. Good Ki-67 immunostaining was observed for all microwave oven heating times in tissue fixed for 4 hr. In contrast, poor immunostaining was observed in tissue fixed for 48 hr unless a heating time of at least 14 min was used. Tonsil fixed for 24 or 48 hr showed a significant increase in percentage positive nuclear area after microwave times of 14 or 21 min. Prolonged heating time (up to 49 min) had no effect on the quality of Ki-67 staining in tissue fixed for 4 or 48 hr.

Formaldehyde↗
PubMed1991

Semiautomation of preparation of fixed paraffin-embedded tissue for DNA analysis.

The usual manual preparation of single-cell suspensions from fixed paraffin-embedded tissue sections for flow cytometric (FCM) DNA ploidy analysis is a time-consuming, labor-intensive technique that requires 70 minutes to deparaffinize and rehydrate 50 microns sections as the initial step. Manual deparaffinization was compared with two semiautomated methods using an automatic slide stainer with either a 70-minute or 35-minute schedule. Samples from 6 normal tissues and 21 tumors (13 diploid and 8 aneuploid) were prepared using all three methods and analyzed by FCM. The mean cell counts in all samples were over 10(6). The DNA indices for the three samples prepared from a given tissue showed no significant differences. Using the 70-minute automation schedule, no aneuploid peaks were lost, and the ratio of G0G1 normal cells to aneuploid tumor cells was maintained. The automation of deparaffinization can thus provide a significant reduction in the labor need to produce single-cell suspensions for FCM; it can be especially helpful when handling large numbers of tumors. At the same time, the automated procedure decreases the exposure to hazardous chemicals and lowers the chance of losing tissue.

DNA↗
PubMed1980

Application of colloidal iron method to semithin sections of epoxy embedded tissues.

Hale's colloidal iron reaction for acid mucopolysaccharides was applied to semithin sections of Epon-embedded tissues routinely processed for electron microscopy. The reaction was found to be positive only after partial removal of the resin in NaOH/absolute ethanol solution; its sensitivity, however, did not reach that obtained in paraffin or frozen sections. The duration of the Epon-removing procedure seems to be crucial for the specificity of staining.

Animals↗
PubMed2005

hTERT expression in melanocytic lesions: an immunohistochemical study on paraffin-embedded tissue.

BACKGROUND: Telomerase plays a role in the immortalization of cells and carcinogenesis. Previous studies have yielded conflicting results on whether human telomerase RNA (hTER) expression differs in nevi, atypical nevi and melanomas using polymerase chain reaction-based telomeric repeat amplification protocol or in situ hybridization assays. The aim of this study was to evaluate human telomerase reverse transcriptase (hTERT) staining in melanocytic lesions on paraffin-embedded tissues. METHODS: Paraffin-embedded sections from 12 acquired nevi, seven dysplastic nevi, 11 Spitz nevi, eight primary invasive melanomas, and three metastatic melanomas were studied for staining intensity (0-3+) and percentage of labeled cells with anti-hTERT. RESULTS: hTERT staining was observed in most cells (>75%), in all but three lesions, and was of greater intensity in the nucleus, especially the nucleolus, compared with the cytoplasm. Spitz nevi tended to have weaker hTERT staining (mean = 1.7) compared with acquired nevi (mean = 2.2), dysplastic nevi (mean = 2.4), primary melanomas (mean = 2.4), or metastatic melanomas (mean = 3). CONCLUSIONS: Although telomerase activity was weaker in Spitz nevi, there was overlap with other nevi and primary invasive melanomas in our small series. Thus, hTERT expression does not appear to be a reliable adjunct to the histological diagnosis of primary melanocytic lesions.

Cell Nucleus↗
PubMed1990

Southern and dot blot analysis of DNA from formalin-fixed, paraffin-embedded tissue samples from colonic carcinomas.

Two extraction methods for the isolation of DNA from formalin-fixed, paraffin-embedded tissue samples from colonic carcinomas were compared. The processed DNAs were compared with DNAs from fresh specimens of the same tumors. The two extraction methods gave similar results. Formalin-fixation and paraffin-embedding irreversibly denatured DNA and consequently decreased the extraction yield and interfered with the quantitative measurement of DNA. Southern blot and dot blot analysis of processed and native DNA was performed using a c-myc and an actin probe. The results show that for Southern analysis processed DNA can be used but, due to the generation of random breaks, the restriction fragments have to be small. Furthermore, the fixation-induced crosslinking of DNA appears to hamper hybridization. For these reasons processed DNA can be analyzed better by dot blot rather than Southern blot hybridization.

Blotting, Southern↗