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Immunocytochemical detection of androgen receptor in human temporal cortex characterization and application of polyclonal androgen receptor antibodies in frozen and paraffin-embedded tissues.

Immunocytochemical and biochemical studies have demonstrated the presence of androgen receptor protein in various regions of the rodent and non-human primate cortex. Localization of androgen receptor in the human brain has, however, not been studied as extensively, because of difficulties in obtaining suitable tissue samples. In the present study, we have localized androgen receptors in both frozen and paraffin-embedded temporal cortex from epileptic patients undergoing resection. Polyclonal antibodies were raised against fusion proteins containing fragments of the human androgen receptor protein. The antibodies were affinity-purified against the corresponding fusion protein. Immunoprecipitation and Western blotting using extracts from human cell lines demonstrated the specificity of the antibodies for the human androgen receptor and lack of cross-reactivity with other steroid hormone receptors. Immunocytochemistry was performed on frozen and paraffin sections of human temporal cortex and in paraffin-embedded benign hyperplastic prostates (BPH), as well as prostate and breast carcinomas, by the streptavidin-biotin-peroxidase method. Antigen-retrieval was performed in paraffin-embedded sections using microwave irradiation. Specific nuclear and cytoplasmic immunoreactivity for androgen receptor was detected in neurons, astrocytes, oligodendrocytes, and microglia cells of the temporal cortex. In contrast, only nuclear staining was observed in BPH, prostate and breast carcinomas. Immunoprecipitation of human temporal cortex lysate and subsequent Western blot analysis demonstrated the expression of a 98 kDa immunoreactive protein, slightly smaller than the reported molecular weight of the wild-type androgen receptor. These results provide further evidence for the expression of androgen receptor in the human temporal cortex. The use of these immunocytochemical techniques should enable the retrospective determination of possible changes in androgen receptor expression in a variety of archival paraffin-embedded tissues, including samples of the human central nervous system.

Adolescent↗

Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic.

Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ngg(-1) for short-chain chlorinated paraffins, and 5575 ngg(-1) for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%.

Czech Republic↗

A method to generate antigen-specific mAb capable of staining formalin-fixed, paraffin-embedded tissue sections.

Abnormalities in HLA class I antigen expression are frequently found in malignant tumors. Their potential role in the clinical course of the disease and in the outcome of T cell-based immunotherapy has stimulated interest in the characterization of the molecular mechanisms underlying HLA class I antigen abnormalities in malignant cells. Multiple mechanisms have been identified. Among them are abnormalities in antigen processing machinery (APM) component expression. In spite of this information, APM component expression in malignant lesions has been investigated only to a limited extent because of the lack of availability, for most APM components, of monoclonal antibodies (mAb) which stain formalin-fixed, paraffin-embedded tissues. The latter are the substrate of choice in immunohistochemical (IHC) reactions. To overcome this limitation, we have developed a simple and reproducible method to generate APM component-specific mAb which stain formalin-fixed, paraffin-embedded tissue sections. This method involves five steps: (i) immunogenic amino acid sequences, which display low homology with their mouse counterparts when possible, are identified in APM components and utilized to synthesize peptides; (ii) BALB/c mice are immunized with keyhole limpet hemocyanin (KLH)-conjugated synthetic peptides and with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)-purified recombinant APM component proteins; (iii) immunized mice, which develop high titer APM component-specific antibodies, are utilized to generate hybridomas which are screened for APM component-specific antibody production by Western blotting assays, with lymphoid cell lysates; (iv) identified APM component-specific mAb are characterized in their specificity and in their reactivity with permeabilized cells in ELISA and/or flow cytometry; and (v) mAb, with the appropriate reactivity pattern, are tested in IHC reactions with formalin-fixed, paraffin-embedded tissue sections. The use of the methodology we have developed resulted in the generation of a panel of APM component-specific mAb capable of staining formalin-fixed, paraffin-embedded tissue sections in IHC reactions. These reagents will facilitate the analysis of APM component expression in tissues under physiological and pathological conditions. In addition, the methodology we have described is likely to be applicable to other antigenic systems to develop mAb capable of detecting protein components of interest in formalin-fixed, paraffin-embedded tissue sections.

Amino Acid Sequence↗

Monoclonal antibodies raised to paraffin wax embedded archival tissue; feasibility study of their potential to detect novel antigenic markers.

A study to determine the feasibility of using archival paraffin wax embedded tissue to generate monoclonal antibodies is described. Specifically, monoclonal antibodies were raised to paraffin wax embedded normal human kidney tissue to test the possibility of producing antibodies to such tissue samples prior to attempting generation of antibodies to valuable archival tissue. Multiple sections (10 x 5 microm) were pooled and dewaxed as for immunohistochemical procedures and combined with Freund's adjuvant for immunization of BALB/c mice in vivo. Immunized spleen cells were fused with SP2 myeloma cells and subsequent clones screened on paraffin wax embedded normal human kidney sections, a range of cell lines and normal mouse tissue. Supernatants from 11 wells (from a total of 90 wells screened) showed different staining patterns on sections of paraffin wax embedded kidney. One clone, 1/11C, (isotype IgG1) which exhibited strong staining on all kidney tubules by immunohistochemical studies (glomeruli interstitium and vessels were unstained) and identified a band at 52 kDa on immunoblots of dewaxed kidney tissue (as used for immunogen) was chosen for further characterization. Immunoblotting of five mammalian cell lines showed differential expression of this 52 kDa band (distinct expression on 3/5, weak expression on 2/5 cell lines) whereas, all cell lines displayed a band at 44 kDa and a third band at 70 kDa was observed on 2/5 cell lines. In mouse tissue extracts, the 52 kDa band was identified in kidney tissue only (not in the lung, liver or spleen) with the 44 kDa and 70 kDa bands weakly expressed in all tissues. This preliminary investigation of a novel approach to identifying possible new antigenic markers or producing monoclonal antibodies which react better to known antigens on sections of paraffin wax embedded tissue showed that this method is feasible. The need to have a comprehensive screening system in place and the ability to identify potentially useful clones after the initial screening is paramount due to the relative scarcity of screening material (archival tissue sections) and the tedious nature of the screening method.

Animals↗

Modeling of nuclide release from low-level radioactive paraffin waste: a comparison of simulated and real waste.

Nuclide leaching models based on mass transfer theory are reviewed and evaluated to analyze the leaching test results of simulated and real paraffin waste from Korean nuclear power plants (NPPs). An empirical model (EM), bulk diffusion model (BDM), coupled diffusion/dissolution model (CDDM), shrinking core model (SCM), modified SCM (MSCM), and uniform reaction model (URM) are selected for comparison. In case of simulated paraffin waste form, the experimental results are satisfactorily explained by the SCM which is based on a diffusion-controlled dissolution reaction. Leaching behavior of real paraffin waste form is well predicted by URM that considers inter-aggregated porous medium and intra-aggregated porous medium separately. If real paraffin waste forms are manufactured with relatively uniform composition, their leaching behaviors are expected to be similar to those of simulated paraffin waste forms.

Diffusion↗

Leaching characteristics of paraffin waste forms generated from Korean nuclear power plants.

Leaching tests of paraffin waste forms including boric acid, cobalt, strontium and cesium were performed to investigate the leaching characteristics of paraffin waste forms which had been generated in Korean nuclear power plants. The leaching tests were conducted according to ANSI/ANS-16.1 test procedure and the cumulative fractions leached (CFLs) of boric acid, cobalt, strontium and cesium were obtained. The compressive strength before and after the leaching test was measured for various waste forms with different mixing ratios of boric acid to paraffin. It was observed that boric acid and other nuclides immobilized within paraffin waste forms were congruently released and the leaching rates were influenced by reacted layer depth as the dissolution reaction progressed. A shrinking core model based on the diffusion-controlled dissolution kinetics was developed in order to simulate the test results. The CFLs and the leaching rates were well expressed by the shrinking core model and the cross-sectional view of specimen after the test demonstrated the applicability of this model with the shrinking dissolution front to the leaching analysis of paraffin waste forms.

Boric Acids↗

Improvement of nuclide leaching resistance of paraffin waste form with low density polyethylene.

Low-level liquid borate wastes have been immobilized with paraffin wax using a concentrate waste drying system (CWDS) in Korean nuclear power plants. The possibility for improving chemical durability of paraffin waste form was suggested in this study. A small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form. The influence of LDPE on the leaching behavior of waste form was investigated by performing leaching test according to ANSI/ANS-16.1 procedure during 325 days. It was observed that the leaching of nuclides immobilized within paraffin waste form made a marked reduction although little content of LDPE was added to waste form. The acceptance criteria of paraffin waste form associated with leachability index (LI) and compressive strength after the leaching test were fully satisfied with the help of LDPE.

Cesium Radioisotopes↗

PCR detection of Actinobacillus pleuropneumoniaeapxIV gene in formalin-fixed, paraffin-embedded lung tissues and comparison with in situ hybridization.

AIMS: Formalin-fixed, paraffin-embedded lung tissues from pigs experimentally infected with 12 Actinobacillus pleuropneumoniae serotypes were used to develop nested PCR for the detection of apxIV gene. METHODS AND RESULTS: The PCR results from formalin-fixed, paraffin-embedded tissues were compared with in situ hybridization. The apxIV gene was detected in formalin-fixed, paraffin-embedded lung tissues from all 39 pigs experimentally infected with 12 A. pleuropneumoniae serotypes by nested PCR. In situ hybridization produced a distinct positive signal in all 39 pigs experimentally infected with 12 A. pleuropneumoniae serotypes. Agreement rates between nested PCR and in situ hybridization were 100% for the detection of apxIV gene in formalin-fixed paraffin-embedded lung tissues. Acceptable PCR signals were detected from lung tissues fixed for periods up to 180 days. CONCLUSIONS: The apxIV gene is species-specific rather than serotype-specific and is therefore an important diagnostic marker. The nested PCR assay would be a useful method for the detection of apxIV gene to diagnose A. pleuropneumoniae infection when formalin-fixed tissues are submitted. SIGNIFICANCE AND IMPACT OF THE STUDY: This study confirmed the possibility of using formalin-fixed, paraffin-embedded tissues for the diagnosis of A. pleuropneumoniae infection in pigs.

Actinobacillus pleuropneumoniae↗

Immunohistochemical detection of CD5 with monoclonal antibody 4C7 on paraffin sections.

CD5 is useful for the classification of low-grade B-cell lymphomas, because it is aberrantly expressed in B-cell chronic lymphocytic leukemias/small lymphocytic lymphomas (B-CLLs/SLLs) and mantle cell lymphomas (MCLs), but not in the other well-described low-grade B-cell lymphomas. Therefore, we tested the utility of monoclonal antibody (MAb) 4C7 to detect CD5 on paraffin sections of 22 cases with low-grade B-cell lymphomas and 4 cases with high-grade B-cell lymphomas and compared the results with CD5 detection by analysis of fresh tissue with a fluorescent-activated cell sorting (FACS). After heat-induced epitope retrieval we could detect CD5 on paraffin sections in all MCLs and B-CLLs/SLLs, identical to the results of flow cytometry. Eleven of 12 cases that showed no CD5 expression by FACS analysis were also negative on paraffin sections. In only one case of a presumed blastoid MCL, CD5 was detectable by immunohistochemistry but not by FACS analysis. We conclude that MAb 4C7 against CD5 is a useful paraffin-reactive marker, especially to correctly identify MCLs on paraffin sections.

Antibodies, Monoclonal↗

Variation in reference cells for DNA analysis of paraffin-embedded tissue.

Selection of the diploid reference cells used in flow cytometric DNA analysis of paraffin-embedded tissue is inconsistent in the literature. To determine which types of cells were most suitable for use as reference cells, benign paraffin-embedded tissue was evaluated from nine randomly selected autopsies. Benign kidney, lymph node, gastrointestinal mucosa, laryngeal mucosa, bronchial mucosa, bladder mucosa, pancreas, and, when available, prostate tissue were studied. Ten paraffin-embedded surgical specimens also were studied. In the autopsy specimens, great variability in the mean peak channels was noted on intrapatient evaluation and even more variability was present when comparing similar organs (especially lymph nodes) from different patients. Similar results were obtained using lymph nodes from surgical specimens. It is concluded that the most suitable diploid reference cells for DNA analysis of paraffin-embedded tissue are the benign cells present in the paraffin tumor block that have been processed in the same way as the tumor cells.

Aged↗

Loss of tumor marker-immunostaining intensity on stored paraffin slides of breast cancer.

BACKGROUND: We previously observed decreased p53 immunostaining over time in paraffin-embedded sections of ductal carcinoma in situ of the breast of women; these sections had been stored on slides at room temperature. This observation suggests that slide storage adversely affects p53-immuno-staining intensity and could result in spurious negative staining for p53 in patient samples. PURPOSE: The goals of this study were to determine the time course and factors influencing loss of p53 immunoreactivity and to investigate whether a similar loss of reactivity occurs with other antigens commonly used to study breast cancer. METHODS: Serial sections cut from 12 formalin-fixed, paraffin-embedded, p53-positive invasive ductal carcinomas of the breast were stored on slides at room temperature or at 4 degrees C, with or without an additional paraffin coating, for 2, 4, 8, or 12 weeks. For each case, freshly cut slides from the same block (day 0) and stored slides were simultaneously stained for p53 by use of an automated immunostainer. Slides cut from formalin-fixed, paraffin-embedded breast carcinomas and stored for 12 weeks were also stained for factor VIII-related antigen (n = 12), estrogen receptor (ER) (n = 9), and Bcl-2 protein (n = 9). The staining intensity of all slides was assessed by visual microscopic examination and was also quantified by image analysis. Quantitative results were expressed as a percentage (mean +/- standard error) of the staining intensity on day 0. Data were analyzed by the Friedman Repeated Measures Analysis of Variance on Ranks, with statistical significance set at two-sided P < .05. RESULTS: The intensity of p53 staining decreased over time in nine (75%) of the 12 cases studied. In three (or 25% of all cases studied) of the nine cases that showed decreased p53 staining, slides stored for 12 weeks were scored as p53 negative. Antigen loss on slides stored at 4 degrees C was significantly less than that on slides stored at room temperature at all time points (all P < .05). At 12 weeks, the average staining intensity of slides stored at 4 degrees C was 33.2% +/- 9% of that on day 0 compared with 8.4% +/- 3% of that on day 0 for slides stored at room temperature (P < .001). Paraffin coating of the sections did not significantly diminish antigen loss at either room temperature or 4 degrees C, except for slides stored at room temperature for 12 weeks. The intensity of factor VIII staining decreased in nine of 12 cases (average staining intensity, 37.3% +/- 6% of that on day 0 at 12 weeks; P = .0001). The intensity of ER and Bcl-2 staining decreased in all nine cases studied at 12 weeks (average staining intensity, 14.0% +/- 6% and 21.0% +/- 4% of that on day 0, respectively; P = .0001 for each). CONCLUSIONS AND IMPLICATIONS: Slide storage, particularly at room temperature, results in substantial loss of p53 reactivity, with some p53-positive cases becoming p53 negative after 12 weeks of storage. Substantial loss of immunoreactivity for factor VIII, ER, and Bcl-2 occurs on slides stored at room temperature for 12 weeks. Storage of unstained slides for up to 12 weeks may lead to false-negative immunostaining for p53 and other antigens.

Biomarkers, Tumor↗

Bone core biopsies. Plastic or paraffin?

Plastic embedding of bone core biopsy specimens has been promoted as providing superior morphology, primarily because semi-thin sections can thereby be cut at 1-2 mu. The major disadvantages of plastic embedding are that it increases the technical load, is more expensive, and potentially has its own intrinsic problems, including difficulties in performing special stains and immunoperoxidase studies. In order to investigate the possibility that semi-thin paraffin sections may provide similar morphological results without the intrinsic disadvantages of plastic sections, we examined 45 bone core biopsy specimens that were sufficiently large to process one half in plastic and the other half in paraffin following decalcification. Both were cut at 1-2 mu. Although many plastic sections appear esthetically more pleasing, semi-thin paraffin sections of very high quality can also be obtained routinely. Additional advantages of paraffin sections were the ability to perform peroxidase studies, lower cost, less technologist time, and avoidance of problems occasionally arising with plastic, such as difficulties with impregnation or problems with polymerization. Peroxidase studies were particularly useful in patients with possible myeloma that was not overt on hematoxylin-and-eosin section and in confirming the presence or source of metastatic carcinoma. We therefore recommend the use of semi-thin (1-2 mu) paraffin sections for routine examination of bone core biopsy specimens.

Biopsy↗

Extraction of DNA from paraffin blocks for Southern blot analysis.

Tissues stored as paraffin blocks are a potential source of DNA for retrospective clinicogenetic analysis. To assess the feasibility of Southern blot analysis, DNA extracted from paraffin blocks was compared with DNA obtained from fresh-frozen controls of the same tissues. Sections 50-100 microns thick cut from paraffin blocks of 11 normal tissues, 18 lymphoid lesions, and 9 gastric carcinoma samples were deparaffinized and incubated at 45 degrees C for 48 to 72 h in a sodium dodecyl sulfate (SDS)/proteinase K solution. Following organic extraction, alcohol precipitation, restriction endonuclease digestion, and gel electrophoresis, DNA was transferred to nylon membranes. 32P-labelled DNA probes for the immunoglobulin heavy-chain locus and T-cell receptor beta-chain gene were hybridized to the normal tissue and lymphoid samples; the gastric cancers were probed for the HER-2/neu protooncogene. Intact DNA was obtained from the majority of formalin-fixed samples, yielding results qualitatively similar to those from fresh tissues. Degradation is the most significant problem in analyzing DNA extracted from paraffin blocks and compromises accurate quantitation. DNA analysis using paraffin-embedded tissue has potential clinical and research applications and may be a particularly useful way to study gene abnormalities in unusual tumors infrequently available as fresh specimens.

Autoradiography↗

Reliable and cost-effective paraffin section immunohistology of lymphoproliferative disorders.

We studied 110 neoplastic and reactive lymphoid proliferations with three monoclonal antibodies--CD20 (L26), CD43 (Leu22), and CD45RO (UCHL1)--on B5-fixed, paraffin-embedded tissue to evaluate the utility of this panel as an immunotypic screen of such lesions. All cases were initially immunotyped by conventional methods. Genotyping by Southern blot hybridization was also done in 54 cases. Seventy-four of 79 malignant lymphomas and both of two hairy cell leukemias were of B-cell origin; and five lymphomas were defined as T-cell lineage. Lineage assignment was identical for paraffin section immunohistology and conventional immunotyping in 73 of 76 B cell and all of five T-cell tumors. CD20 was reactive with 73 of 76 B-cell tumors. CD43 was reactive with 12 of 74 B-cell lymphomas, and CD20/CD43 coexpression was seen in 11 of these cases. CD43 and CD45RO marked all of five and three of five T-cell lymphomas, respectively. Lineage assignment was identical for paraffin immunohistology and genotyping in 48 of 50 cases with identifiable gene rearrangements. Twenty-four nonneoplastic and five Hodgkin's disease cases that were studied also showed similar immunoreactivity patterns by both paraffin and conventional immunotypic methods. This panel of three monoclonal antibodies is an efficient, cost-effective approach for immunotyping most lymphoid proliferations in paraffin sections. Nevertheless, the pathologist should always try to obtain fresh or frozen tissue to aid in resolving occasional discrepant cases, to establish clonality in morphologically ambiguous ones, and to profile prognostically important phenotypic deletions.

Antibodies, Monoclonal↗

Detection of TLS/FUS-CHOP fusion transcripts in myxoid and round cell liposarcomas by nested reverse transcription-polymerase chain reaction using archival paraffin-embedded tissues.

The reciprocal translocation t(12;16)(q13;p11) has been shown to be highly characteristic of myxoid and round cell subtypes of liposarcoma, and the TLS/FUS-CHOP fusion gene that resulted from the translocation is expected to be a diagnostic molecular marker of these sarcomas. In this study, we conducted a nested reverse transcription-polymerase chain reaction (RT-PCR)-based assay to detect the TLS/FUS-CHOP fusion gene transcripts using archival formalin-fixed, paraffin-embedded tumor specimens. Of 18 paraffin-embedded specimens from 16 myxoid and round cell liposarcoma cases, the fusion transcripts could be identified in 16 (89%) specimens from 15 (94%) cases. A sequence analysis using the PCR products confirmed that the detected messages were derived from either type I or type II TLS/FUS-CHOP fusion gene, the latter of which was predominant (80%). The results were consistent in primary and recurrent lesions of the same patients and in paraffin-embedded and snap-frozen samples from the same tumors. In two negative specimens, transcripts of the beta-actin gene could not be detected by RT-PCR, and intact mRNA including the fusion messages might have been degraded. No fusion transcripts were detected in snap-frozen or paraffin-embedded material of other types of tumors with myxoid morphology (seven myxoid malignant fibrous histiocytomas and four lipomas with myxoid change). These results indicate that this molecular assay can be applied to formalin-fixed, paraffin-embedded tumor tissues as a diagnostic aid for these subtypes of liposarcoma.

Adolescent↗

Formalin-fixed and paraffin-embedded nodal non-Hodgkin's lymphomas demonstrate the same chromosome changes as those found in frozen samples: a comparative study using interphase fluorescence in situ hybridization.

Cytogenetic studies in lymphomas classically require fresh or frozen tissue, whereas in many instances only paraffin-embedded biopsies are available. We applied an interphase FISH assay on nuclei extracted from thick paraffin sections to determine accuracy of molecular cytogenetics in such samples. Twenty-three lymphoma samples and 4 reactive lymph nodes were tested with various commercially available DNA probes, and hybridization patterns were compared with those obtained on frozen nuclei counterparts. Successful hybridization with all probes tested was observed for 23/27 (85%) paraffin-embedded tissues and for all (100%) frozen samples, and cut-off levels defining positivity were superimposable for both situations. Chromosome changes were detected in the same way, without any false-positive or false-negative cases. Hybridization signals observed on dewaxed samples were either those classically expected to define the relevant chromosome change or were atypical: all atypical changes could be demonstrated also into nuclei from the frozen counterpart. Moreover, all typical and atypical chromosome changes observed on frozen nuclei were also detected in paraffin-embedded tissues. Our study shows that our interphase FISH assay performed on paraffin-embedded samples is a valuable alternate to conventional methods to ascertain diagnosis of lymphomas as to include patients into therapeutic trials.

Artifacts↗

HSP47 is a useful marker for skin fibroblasts in formalin-fixed, paraffin-embedded tissue specimens.

AIM: This study was undertaken to assess whether heat-shock protein (HSP)47 is a useful cell marker for skin fibroblasts in formalin-fixed, paraffin-embedded skin specimens. BACKGROUND: HSP47, a 47-kDa HSP, is a collagen-specific molecular chaperone localized in the endoplasmic reticulum. HSP47 plays an essential role in collagen biosynthesis in skin fibroblasts. METHODS: Immunohistochemistry was performed to detect HSP47 in skin fibroblast cultures and skin tissue sections. RESULTS: Immunostaining for HSP47 clearly detected skin fibroblasts in paraffin tissue sections as well as in fibroblast cultures and frozen tissue sections. HSP47 staining on paraffin sections from diseased skin specimens revealed that skin ulcer, keloid, nodular fascitis, spindle cell lipoma, and dermatofibroma had strong signals for HSP47 compared with the signals obtained from normal skin. Dermatofibrosarcoma protuberans had many HSP47 positive cells, but signals on individual cells were not as strong as those seen from the above benign proliferative disease samples. In neurofibroma, a small number of faintly positive cells were detected. Our double-immunostaining studies also demonstrated that HSP47 staining distinguished skin fibroblasts from CD68-positive histiocytes/macrophages, factor VIII-related antigen-positive endothelial cells, or factor XIIIa-positive dermal dendritic cells. CD34-positive interstitial cells coexpressed HSP47 in spindle cell lipoma. CONCLUSIONS: These findings indicate that HSP47 staining can detect skin fibroblasts in routine, paraffin-embedded specimens. A panel approach using HSP47 and other cell markers on paraffin sections may help the identification of the cell type involved with mesenchymal proliferative disorders.

Biomarkers↗

Light microscopic identification and semiquantification of polyethylene particles in methylmethacrylate and paraffin-embedded experimental bone implant specimens.

The aim of this study was to evaluate the identification of polyethylene (PE) particles in relatively thick methylmethacrylate (MMA) sections widely used in bone implant research. The sensitivity and specificity were compared between decalcified paraffin-embedded oil red O (ORO) stained and MMA-embedded sections using polarized light. Furthermore, we introduced a grading system to semiquantify the level of PE particles in peri-implant tissue. Paraffin-embedded and MMA-embedded sections were compared concerning intra-observer agreement of the grading system. Moreover, the semiquantitative assessment of particle level was compared between the two section types. We found a sensitivity and specificity of polarized light of 100% for both paraffin ORO-stained and MMA sections. The intra-observer agreement on both types was comparable and acceptable. The ratings of differently processed blocks (MMA- and paraffin-embedded) originating from the same bone implant specimen showed good correlation. Our study showed that relatively thick MMA sections were just as suitable as ORO-stained paraffin sections concerning peri-implant PE particle migration analysis. MMA sections do not allow analysis at cellular level, but unbiased estimation of bone ingrowth into the implant surface based on stereological principles is possible.

Animals↗