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PubMed1995

Detection of Clostridium chauvoei in formalin-fixed, paraffin-embedded tissues of sheep by the peroxidase-antiperoxidase (PAP) technique.

A peroxidase-antiperoxidase (PAP) technique was used to detect Clostridium chauvoei in tissue sections from sheep inoculated intramuscularly with a pure culture of this microorganism. Samples of various tissues were taken for bacteriology, histopathology and immunohistochemistry. A primary antiserum against C. chauvoei for use in the PAP technique was produced in rabbits. Formalin-fixed, paraffin-embedded sections of muscle samples were positively and specifically stained by the PAP technique. The results were consistent with those obtained by bacteriology, but the PAP test was simpler, quicker and less expensive than the bacteriological procedures. The use of the PAP technique would be appropriate for detecting clostridial infections without the constraints of conventional identification methods, especially where laboratory conditions for anaerobic procedures are not readily available.

Animals↗
PubMed1994

In-situ hybridization for demonstration of equine herpesvirus type 1 DNA in paraffin wax-embedded tissues and its use in horses with disseminated necrotizing myeloencephalitis.

The detection of equine herpesvirus type 1 (EHV-1) in infected cell cultures, and in tissues taken at necropsy, by the in-situ hybridization technique is described. A 4.9 kb Bam HI fragment of EHV-1 vaccine strain RacH was used as a probe after labelling with [alpha-32P] thymidine 5'-triphosphate ([32P]TTP) or digoxigenin-deoxyuridine 5'-triphosphate (dUTP). Both probes specifically detected EHV-1 DNA in either cytospin or paraffin wax-embedded preparations of infected cells. The digoxigenin-labelled probe was further used to examine tissue sections of equine fetuses which had been aborted due to EHV-1 infection. In all cases positive hybridization signals were mainly associated with the nuclei. Positive results were confirmed by immunostaining of EHV-1 antigen in adjacent sections. However, both methods failed to detect EHV-1 in spinal cord sections of six horses suffering from disseminated necrotizing myeloencephalitis (DNM). These results support the hypothesis that DNM is not caused by a productive viral infection of parenchyma of the nervous system but is immunologically mediated.

Animals↗
PubMed1994

Detection of the Philadelphia chromosome in paraffin-embedded tissue by fluorescence in situ hybridization.

The bcr-abl fusion gene situated on the Philadelphia chromosome is a tumor-specific marker for chronic myelogenous leukemia. We evaluated the usefulness of two color fluorescence in situ hybridization with bcr and abl probes as a means of detecting the Philadelphia chromosome in formalin-fixed, paraffin-embedded sections of spleen and lymph node specimens from eight patients with myeloproliferative diseases showing clinical and morphological features of chronic myelogenous leukemia in accelerated phase. Our analysis showed co-localized hybridization signals corresponding to the bcr-abl fusion product in tissue sections from six patients previously found to have the Philadelphia chromosome by conventional cytogenetics and polymerase chain reaction. The two remaining specimens lacked bcr-abl fusion signals and were obtained from patients who were negative for the Philadelphia chromosome by cytogenetic and polymerase chain reaction analysis. We conclude that fluorescence in situ hybridization is a sensitive method for the detection of the bcr-abl fusion gene in histological specimens from patients with chronic myelogenous leukemia. The technique may become a useful tool in the evaluation of tissue specimens from patients with chronic myelogenous leukemia and related Philadelphia chromosome-positive hematologic malignancies.

Fusion Proteins, bcr-abl↗
PubMed1997

Production and characterization of a new monoclonal antibody effective in recognizing the CD3 T-cell associated antigen in formalin-fixed embedded tissue.

Phenotypic analysis of lymphoproliferative disorders is now considered mandatory for accurate classification which is the basis for optimum patient management. This is presently carried out in most cases using a range of antibodies recognizing B and T-cell antigens effective in paraffin sections, and an antibody to CD 3 is currently a key member of such panels, indicating T-cell phenotype. Current antibodies to CD3 are polyclonal with the inherent disadvantages of this type of reagent compared to monoclonal antibodies. In this study, we have used a recombinant fusion protein representing part of the epsilon subunit of the CD3 molecule to generate a novel monoclonal antibody (NCL-CD3-PS1) effective in paraffin sections. The antibody has been characterized biochemically and by immunohistochemistry using a wide range of normal and pathological tissues. Lineage and phenotype specificity have been supported in our study and results from other laboratories are awaited with interest.

Antibodies, Monoclonal↗
PubMed1994

p53 immunolabeling in archival paraffin-embedded tissues: optimal protocol based on microwave heating for eight antibodies on lung carcinomas.

The prognostic value of p53 gene mutations is dealt with by several recent reports. However, retrospective assessment of p53 tumor status on archived samples has been prevented by p53 epitope alteration during routine fixation and embedding procedures. This study aimed at establishing a reproducible low-cost protocol to retrieve not only N-terminal, but also midregion and C-terminal, epitopes, with special attention to possible artifacts induced by epitope retrieval procedures. Using microwave heating, we compared the epitope retrieval efficiency of five solutions with eight commercial antibodies on 21 lung carcinomas for which frozen tissue and samples fixed with formalin and Bouin's liquid were available. All eight epitopes were retrieved, citrate buffer proving efficient for seven. PAb 240 epitope was restored by target unmasking fluid only. No false positivity was observed. Fixation-induced loss of p53 immunoreactivity was minimal for formalin (two of 10 tumors for one antibody each), more significant for Bouin (six of 10 tumors for one to five antibodies). On the other hand, staining intensity was maintained or even improved, and nonspecific staining reduced, through fixation. We conclude that p53 stabilization can be detected on routinely processed archival tumor samples with a reliability similar to that of frozen tissue by means of a microwave-based procedure and a panel of at least three antibodies, with epitopes on the N-terminal, C-terminal, and midpart of the molecule.

Antibodies, Monoclonal↗
PubMed2004

Detection of Mycobacterium tuberculosis complex in formalin-fixed, paraffin-embedded tissue specimens with necrotizing granulomatous inflammation by strand displacement amplification.

Rapid, reliable diagnosis of tuberculosis is essential to initiate correct treatment, avoid severe complications, and prevent transmission. Conventional microbiological methods may not be an option if samples are formalin-fixed and paraffin-embedded (FFPE) for histopathological examination. With the demonstration of necrotizing granulomatous inflammation, tuberculosis becomes an important differential diagnosis, although it was not initially suspected. Following paraffin extraction, BDProbeTec ET strand displacement amplification for detection of Mycobacterium tuberculosis complex (MTC) was applied to 47 prospectively and 19 retrospectively collected FFPE samples from various sources with granulomatous inflammation and results were compared to tuberculosis notification. Of the prospective samples, 20 were from patients who were notified as having tuberculosis and the assay was positive in 18 (90%). Specificity was 100%. For 27 of the patients with prospectively collected FFPE specimens, culture was performed on a specimen collected at a later date from the same location. Culture revealed MTC in 14 and nontuberculous mycobacteria in four. BDProbeTec ET was positive in 13 (92.8%) of the patients with positive MTC culture and negative in the remaining. The sensitivity and specificity in 19 archival samples was 40% and 100%, respectively, compared to notification data. The assay provided rapid, correct diagnosis on different sources of FFPE samples collected prospectively and therefore offers an important supplementary method for patients where tuberculosis was not initially suspected.

Fixatives↗
PubMed1996

In situ hybridization technique for the detection of swine enteric and respiratory coronaviruses, transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV), in formalin-fixed paraffin-embedded tissues.

The in situ hybridization (ISH) technique was developed to detect the swine coronaviruses, transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV), in cell culture and tissue sections from TGEV-or PRCV-infected pigs. The 35S-labeled RNA probes were generated from two plasmids pPSP.FP1 and pPSP.FP2 containing part of the S gene of TGEV. The procedure was first standardized in cell cultures. The radiolabeled pPSP.FP2 probe detected both TGEV and PRCV in virus-inoculated cell cultures, whereas pPSP.FP1 probe detected TGEV but not PRCV. The probe was then used to detect TGEV or PRCV in tissues of pigs experimentally infected with TGEV or PRCV or naturally infected with TGEV. Again, the probes detected TGEV in intestines of experimentally and naturally infected pigs and PRCV in the lungs of experimentally infected pigs. TGEV RNA was detected mainly within the enterocytes at the tips of villi and, less often, within some crypt epithelial cells. PRCV was shown to replicate mainly in the bronchiolar epithelial cells and in lesser amount in type II pneumocytes, type I pneumocytes, alveolar macrophages and bronchial epithelial cells, respectively. ISH has potential applications as a diagnostic test for the detection and differentiation of TGEV and PRCV in tissues and in studies to gain a better understanding of the mechanism of pathogenesis of enteric and respiratory coronavirus infections.

Animals↗
PubMed2006

Multiple gene expression analyses in paraffin-embedded tissues by TaqMan low-density array: Application to hedgehog and Wnt pathway analysis in ovarian endometrioid adenocarcinoma.

Recent studies have shown the hedgehog and Wnt families of signaling proteins to be associated with tumor initiation, growth, and survival. However, these pathways remain unexplored in ovarian endometrioid adenocarcinoma (OEA). Here, we describe a novel TaqMan low-density array to examine the expression of 26 and 20 genes in the hedgehog and Wnt pathways, respectively, in six matched snap-frozen and formalin-fixed, paraffin-embedded (FPE) OEA specimens. Expression values were normalized to uninvolved ovarian epithelium. Gene expression in matched frozen and FPE tissues demonstrated significant concordance (r = 0.92, P < 0.0001). However, comparison of amplified and unamplified RNA from frozen OEA tissues revealed an altered molecular profile in amplified RNA. Amplification of RNA from FPE tissues was not successful. The expression of Desert hedgehog (DHH), Indian hedgehog (IHH), Hedge-hog interacting protein (HHIP), Wnt10B, Wnt9B, and Wnt inhibitory factor (WIF1) were tumor-specific with no detectable expression in normal ovarian epithelium. In addition, several genes were significantly (P < 0.025) down-regulated in OEA, including cyclin E2, Porcupine, c-Myc, and Axin 2 (4.8-, 3.6-, 2.9-, and 1.9-fold, respectively). TaqMan low-density array provides an effective multivariate technique for examining gene expression in RNA isolated from either snap-frozen or archival FPE tissues and can identify tumor-specific genes, possibly leading to novel treatments.

Animals↗
PubMed1997

Detection of thymidylate synthase gene expression levels in formalin-fixed paraffin embedded tissue by semiquantitative, nonradioactive reverse transcriptase polymerase chain reaction.

We describe a new, simple and reliable semiautomated strategy for quantifying mRNA from archival specimens by using oligo(dT)25 paramagnetic beads and the reverse-transcriptase polymerase chain reaction (PCR) coupled with quantitative digital image analysis (Q-DIA). To evaluate the experimental conditions, we examined thymidylate synthase (TS) gene expression in mRNA isolated from both flash-frozen and formalin-fixed paraffin-embedded human biopsy samples using biopsy material obtained from 2 patients prior to chemotherapy with 5-fluorouracil. Following the electrophoretic separation of the PCR products through a 20% polyacrylamide gel, quantitation of the perimeters of the silver-nitrate-stained PCR products will be done by Q-DIA using a video frame-grabber board attached to a CCD camera using Image-Pro+ software. Validation of this approach will involve a comparison of the observed gene expression levels to TS protein levels obtained by tissue homogenization assays of TS, tetrahydrofolate, 5,10-methylenetetrahydrofolate, 2'-deoxyuridine-5'-monophosphate and 5-fluoro-2'-deoxyuridylate (FdUMP), by established [3H]FdUMP ligand-binding assays. The novelty of this method is that it offers a low-cost means whereby Q-DIA is performed directly from the gel to rapidly and accurately determine the level of TS gene expression, which is standardized against the beta-actin housekeeping gene. In the protocol described herein, gene expression studies can be done quickly and without the use of radioactive substances in both normal clinical samples shock frozen at the time of surgical excision and in formalin-fixed paraffin-embedded archival samples, which are commonly available in all hospital pathology departments. To demonstrate the utility of this method, mRNA was extracted from both nonpathological and tumor biopsies originating from both types of material from the same patients. TS gene expression in the flash-frozen and archival materials was compared to the level of TS intracellular enzyme activity in the same samples and a correlation of 89 and 80% between the shock-frozen and archival material relative to TS intracellular enzyme activity levels was observed. These findings suggest that routine semiautomated quantitative analysis of rare mRNA transcripts, e.g. TS, from archival material can be applied for retrospective studies.

DNA, Complementary↗
PubMed2002

Protein overexpression and gene amplification of c-erbB-2 in breast carcinomas: a comparative study of immunohistochemistry and fluorescence in situ hybridization of formalin-fixed, paraffin-embedded tissues.

We evaluated 173 consecutive breast carcinomas for c-erbB-2 using a combination of immunohistochemistry (IHC) with a commercial polyclonal antibody (Nitirei) and dual-color fluorescence in situ hybridization (FISH) using the c-erbB-2-specific probe and the chromosome 17 centromere-specific probe from Vysis (Downers Grove, IL) and compared the results with the histologic characteristics of intraductal spread, cancer invasion, and intratumoral heterogeneity. With correction for chromosome 17 copy number, c-erbB-2 amplification was observed in 26 tumors (13.5%): high-level amplification in 23 tumors, and low-level amplification in 3. The gene amplification was positively correlated with c-erbB-2 protein overexpression, defined as 2+ or 3+ immunostaining, on a case-by-case basis (P < .000001). All 3+ immunostaining tumors (19 tumors) showed high-level amplification, although gene amplification was found in only 5 of 27 2+ immunostaining tumors. Although the rates of overexpression and gene amplification did not differ in ductal carcinomas in situ and invasive carcinomas (P = .46 and .53, respectively), they were significantly higher in invasive carcinomas with intraductal spreading (P < .0001). Intratumoral heterogeneity of c-erbB-2 amplification was found in only 1 case; however, in 17 invasive carcinomas, intraductal components expressed c-erbB-2 more intensely than invasive components. We conclude that in breast carcinomas, c-erbB-2 overexpression occurs mostly in tumors with high-level gene amplification, and such overexpression appears to endow carcinoma cells with the capacity for intraductal spreading. The best method for detecting breast carcinomas with c-erbB-2 aberrations using archival tissues is to screen cases by IHC; however, follow-up FISH assays are indispensable for excluding false-positive results.

Adult↗