Determination of hepatic iron concentration in fresh and paraffin-embedded tissue.
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A tiny fragment of high-grade carcinoma was found in histologic sections and in the paraffin block of a benign cervical polyp from a patient with no clinical evidence of malignancy. Thus, it raised the suspicion of block contamination. No malignant tumor was processed the same day as the polyp; however, a similar tumor had been processed 6 days earlier. Multiplex DNA short tandem repeat analysis was applied to paraffin-extracted tissue samples obtained from the polyp, the suspected contaminant, the patient's additional cervical biopsy specimen, and the putative source of contamination. The results demonstrated that the suspected contaminant and the patient's cervical tissue could not have come from the same patient and that the suspected contaminant derived from the tumor processed earlier, without reasonable doubt. We hypothesize that this friable tumor escaped from cassettes into the processor and contaminated the polyp specimen. Multiplex DNA short tandem repeat analysis can be applied to determine the provenance of minute tissue samples in surgical pathology.
A simple reproducible protocol for detecting multiple copy human genes and viral DNA in routine formalin fixed paraffin embedded tonsil and brain, by in situ hybridisation with biotinylated probes, is described. The protocol consists of digestion of formalin fixed paraffin sections, with 0.4% pepsin in 0.01 M hydrochloric acid for one hour at 37 degrees C, followed by hybridisation with biotinylated probes. The biotinylated probes used for establishing the conditions for in situ localisation of DNA were total placental DNA (TG1), pHY 2.1 (a Y chromosome probe), and herpes simplex virus I and II. In human male tonsil TG1 labelled all nuclei and pHY 2.1 reacted only with nuclear Y bodies. In herpes encephalitis the virus was detected in some glial cells and neurones.
The expression of neu oncoprotein was assayed by immunohistochemistry (IHC) on 245 paraffin-embedded, Stage I and II breast cancers from patients treated at the City of Hope between the years 1980 and 1987. Only cases showing membrane staining were scored as positive. Fifty-four (22%) of the tumors stained positively for neu. Probability of disease-free survival (DFS) and overall survival (OS) was compared based on neu positivity and other prognostic factors. Overall, DFS and OS did not differ significantly among neu-positive and neu-negative cases. However, when only cases with favorable (Stages I and II) nuclear grade were analyzed, OS and DFS were significantly lower in neu-positive cases, with a 9-fold increase in risk of death and a 3-fold increase in risk of relapse. Our findings suggest that immunohistologic study of neu oncoprotein may help to define patients at greater risk among low-stage/low-nuclear-grade patients with breast cancer, a group hitherto recognized as having a good prognosis.
Samples from the mammary tissue of 14 lactating goats (12 naturally infected and two experimentally infected) were examined for the presence of Mycoplasma agalactiae. A monoclonal antibody (5G12) was applied to formalin-fixed, paraffin-wax-embedded sections and labelled by the avidin-biotin peroxidase complex (ABC) method. Histological examination of tissue sections revealed strong immunoreactivity in all animals included in the study. Mycoplasma agalactiae antigen was mainly detected in the cellular debris at the periphery of purulent exudates present within lactiferous sinuses, and lactiferous and interlobular ducts. In addition, M. agalactiae organisms appeared in the cytoplasm of the epithelium of ducts, and in infiltrating macrophages and neutrophils within the ducts, alveoli, interstitial tissue and regional lymph node sinuses. It is concluded that this monoclonal antibody-based immunohistochemical technique is an efficient and specific method for the post-mortem detection of M. agalactiae in cases of clinical mastitis as well as being a useful tool for the study of the route of infection and cellular types involved during mastitis caused by this organism.
Fixatives, fixation additives, paraffin processing reagents, and immunochemical reagents were investigated for effects on preservation of T-lymphocyte surface membrane antigens CD3, CD4, and CD8 in human tonsil. Individual reagent effects were assessed in frozen sections by use of monoclonal antibodies and this information was used to optimize T-cell immunostaining in paraffin sections. Harmful factors were fixation delay, fixation at acid pH, fixation and processing at temperatures above 4 degrees C, hot paraffin wax, proteolytic enzymes, methanolic hydrogen peroxide, Triton X-100, and prolonged iodine treatment. Optimal T-cell demonstration in paraffin sections followed tissue fixation in periodate-lysine-paraformaldehyde dichromate at 4 degrees C, pH 7.5; processing through isopropanol, then xylene or chloroform, at 4 degrees C; and embedding in low melting point wax at 45-50 degrees C. Graded antigen stability occurred: CD3 most stable, CD8 least, and CD4 intermediate. CD4 and CD8 antigen preservation in paraffin sections required critical optimal tissue handling. CD3 was more stable and was also demonstrated in tissue fixed in commercial formalin, glutaraldehyde, and Bouin's fluid when fixation and processing conditions were optimized for pH and temperature. Of the fixation additives studied, polyethylene glycol and several potassium and magnesium salts enhanced immunostaining, whereas calcium chloride and lidocaine were deleterious.
The expression of cytokeratins (CK), involucrin, vimentin, CD34, and alpha-smooth-muscle actin was studied in fetal and adult hair follicles. The first stage of the developing hair follicle is characterized by palisaded, elongated epithelial cells budding from the epidermal basal layer. These cells express CK5/6, CK14, CK17, CK19, and vimentin. During the following weeks of gestation, different structures in the developing hair follicle can be identified and characterized. The matrical cells display only CK19. The keratinocytes of the outer root sheath express CK5/6, CK14, CK17, CK19, and involucrin; those of the inner root sheath, CK4, CK18, and involucrin; those of the isthmus, the same profile as the ORS. In the infundibulum, the basal-layer keratinocytes express CK5/6, CK14, CK17, and CK19, whereas in the suprabasal layers CK1, CK4, CK10, CK14, and CK17 are seen. The adult hair follicle in anagen fails to express CK19 in the matrical cells and isthmus and both CK17 and CK19 in the infundibulum. These profiles of intermediate filaments and other markers appear to be potentially useful in categorizing neoplasms with apparent follicular differentiation.
The etiologic role of human herpesvirus 8 (HHV8) in Kaposi's sarcoma (KS) remains controversial. This polymerase chain reaction (PCR)-based study was undertaken to evaluate the relationship of HHV8 in KS from our geographical region and to determine its utility in formalin-fixed, paraffin-embedded biopsy specimens. Forty-two biopsy specimens were studied, including nine AIDS-associated cases and four from classic KS. Of the 39 patients included, 21 were HIV+ and 18 had no clinical evidence of HIV infection. Only a single (internal) primer pair was used in the PCR. All PCR products were tested with an HHV8 specific probe by dot blot analysis. Seven of the nine AIDS KS specimens were positive for HHV8 on electrophoresis, and all nine were positive after dot blot. Two of four specimens from classic KS were positive for HHV8 on the gel electrophoresis, and three of four were positive on blot confirmation. Non-KS specimens from 15 HIV+ patients yielded one positive venous hemangioma from a man with HHV8-positive KS at another site. Specimens from HIV-unrelated controls with a variety of diagnoses were negative by PCR with blot. The predominant negativity for HHV8 in non-KS lesions suggests that HHV8 is not widespread in our patients. These results demonstrate yet another series linking KS with HHV8 and show that paraffin-embedded biopsy specimens are satisfactory for this technique.
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Production of a new monoclonal antibody designated NCL-5D3 is described. The antibody recognizes several low molecular weight cytokeratins, in particular cytokeratin Moll number 8 as determined by immunoblotting studies, and is highly effective for immunocytochemistry using routinely processed paraffin-embedded material. Staining is enhanced by prior treatment of the sections with trypsin. Assessment using a wide variety of normal and neoplastic tissue indicates reactivity with all tissues of simple or glandular epithelial origin, and in addition with many squamous carcinomas. Thus the antibody should prove of value in diagnostic histopathology.
Improved extraction techniques combined with sensitive real-time reverse transcriptase-polymerase chain reaction may allow detection of mRNA in formalin-fixed, paraffin-embedded (FFPE) materials, but the factors affecting mRNA quantification in clinical material using these methods have not been systematically analyzed. We designed analyses using real-time reverse transcriptase-polymerase chain reaction for quantification of MART-1, beta-actin, and beta(2)-microglobulin mRNAs. The analytical intra- and interassay imprecision (coefficient of variation) was in the range 10 to 20% for all three genes studied. Using these protocols, we studied the influence of tissue autolysis and length of formalin-fixation on mRNA detection in metastatic melanoma. Delay in freezing reduced detectable mRNA, although this was less than predicted and mostly occurred early in autolysis. MART-1, beta-actin, and beta(2)-microglobulin mRNAs were consistently detected in FFPE metastatic melanoma even after fixation for up to 3 weeks, although the total mRNA detected was markedly reduced in fixed compared with fresh tissues (up to 99%). Quantification of MART-1 was, however, possible if this was expressed relative to a housekeeping gene. The polymerase chain reaction product from FFPE tissues could be increased up to 100-fold amplifying short (<136 bp) compared with long amplicons. Variations in time before tissue processing and in fixation length seem to be less important sources of imprecision than previously assumed. Our findings suggest that quantitative analysis of mRNA in archive and routine diagnostic tissues may be possible.
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The use of chelating resin in a simple, rapid and efficient pre-treatment protocol to process formalin-fixed, paraffin-embedded specimens for the polymerase chain reaction (PCR) is described and compared to other pre-treatment techniques. With this modified PCR protocol, a variety of human autopsy and biopsy specimens were investigated for presence of DNA of human papilomaviruses, cytomegalovirus or Epstein-Barr virus. These viruses were detected in a productive or non-/low-productive state. Amplimers generated ranged from 88 to 450 base pairs length. Under the specified technical conditions, a considerable range of DNA molecules can be amplified from paraffin-embedded material, some older than 10 years.
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