Effects of fixation and demineralization on immunohistochemical assessment of canine bone marrow.

Fixation and demineralization protocols for bone marrow (BM) across diagnostic laboratories are not standardized. How different protocols affect histomorphology and DNA amplification is incompletely understood. In this study, 2 fixatives and 3 demineralization methods were tested on canine BM samples. Twenty replicate sternal samples obtained within 24 hours of death were fixed overnight in either acetic acid-zinc-formalin (AZF) or 10% neutral-buffered formalin (NBF) and demineralized with formic acid for 12 hours. Another 53 samples were fixed in AZF and demineralized with hydrochloric acid for 1-hour, formic acid for 12 hours, or ethylenediamine tetraacetic acid (EDTA) for 24 hours. Histologic sections were scored by 4 raters as of insufficient, marginal, good, or excellent quality. In addition, DNA samples extracted from sections treated with the different fixation and demineralization methods were amplified with 3 sets of primers to conserved regions of T cell receptor gamma and immunoglobulin heavy chain genes. Amplification efficiency was graded based on review of capillary electrophoretograms. There was no significant difference in the histomorphology scores of sections fixed in AZF or NBF. However, EDTA-based demineralization yielded higher histomorphology scores than demineralization with hydrochloric or formic acid, whereas formic acid resulted in higher scores than hydrochloric acid. Demineralization with EDTA yielded DNA amplification in 29 of 36 (81%) samples, whereas demineralization with either acid yielded amplification in only 2 of 72 (3%) samples. Although slightly more time-consuming and labor-intensive, tissue demineralization with EDTA results in superior morphology and is critical for polymerase chain reaction (PCR) amplification with the DNA extraction method described in this article.

Introduction: Liquid-based cytology (LBC)-fixed samples can be used for preparing multiple specimens of the same quality and for immunocytochemistry (ICC); however, LBC fixing solutions affect immunoreactivity. Therefore, in this study, we examined the effect of LBC fixing solutions on immunoreactivity. Methods: Samples were cell lines, and specimens were prepared from cell blocks of 10% neutral buffered formalin (NBF)-fixed samples and the four types of LBC-fixed samples: PreservCyt®, CytoRich™ Red, CytoRich™ Blue, and TACAS™ Ruby, which were post-fixed with NBF. ICC was performed using 24 different antibodies, and immunocytochemically stained specimens were analyzed for the percentage of positive cells. Results: Immunoreactivity differed according to the type of antigen detected. For nuclear antigens, the highest percentage of positive cells of Ki-67, WT-1, ER, and p63 was observed in the NBF-fixed samples, and the highest percentage of positive cells of p53, TTF-1, and PgR was observed in the TACAS™ Ruby samples. For cytoplasmic antigens, the percentage of positive cells of CK5/6, Vimentin, and IMP3 in LBC-fixed samples was higher than or similar to that in NBF-fixed samples. The percentage of positive cells of CEA was significantly lower in CytoRich™ Red and CytoRich™ Blue samples than in the NBF-fixed sample (p < 0.01). Among the cell membrane antigens, the percentage of positive cells of Ber-EP4, CD10, and D2-40 was the highest in NBF-fixed samples and significantly lower in CytoRich™ Red and CytoRich™ Blue samples than that in NBF-fixed samples (p < 0.01). The NBF-fixed and LBC-fixed samples showed no significant differences in the percentage of positive cells of CA125 and EMA. Discussion/Conclusion: ICC using LBC-fixed samples showed the same immunoreactivity as NBF-fixed samples when performed on cell block specimens post-fixed with NBF. The percentage of positive cells increased or decreased based on the type of fixing solution depending on the amount of antigen in the cells. Further, the detection rate of ICC with LBC-fixed samples varied according to the type of antibody and the amount of antigen in the cells. Therefore, we propose that ICC using LBC-fixed samples, including detection methods, should be carefully performed.

STUDY QUESTIONCan ovarian tissue morphology be better preserved whilst enabling histological molecular analyses following fixation with a novel fixative, neutral buffered formalin (NBF) with 5% acetic acid (referred to hereafter as Form-Acetic)?SUMMARY ANSWERFixation with Form-Acetic improved ovarian tissue histology compared to NBF in multiple species while still enabling histological molecular analyses.WHAT IS KNOWN ALREADYNBF fixation results in tissue shrinkage in various tissue types including the ovary. Components of ovarian tissue, notably follicles, are particularly susceptible to NBF-induced morphological alterations and can lead to data misrepresentation. Bouin’s solution (which contains 5% acetic acid) better preserves tissue architecture compared to NBF but is limited for immunohistochemical analyses.STUDY DESIGN, SIZE, DURATIONA comparison of routinely used fixatives, NBF and Bouin’s, and a new fixative, Form-Acetic was carried out. Ovarian tissue was used from three different species: human (n = 5 patients), sheep (n = 3; 6 ovaries; 3 animals per condition) and mouse (n = 14 mice; 3 ovaries from 3 different animals per condition).PARTICIPANTS/MATERIALS, SETTING, METHODSOvarian tissue from humans (aged 13 weeks to 32 years), sheep (reproductively young i.e. 3–6 months) and mice (10 weeks old) were obtained and fixed in 2 ml NBF, Bouin’s or Form-Acetic for 4, 8, and 24 h at room temperature. Tissues were embedded and sectioned. Five-micron sections were stained with haemotoxylin and eosin (H&E) and the percentage of artefact (clear space as a result of shrinkage) between ovarian structures was calculated. Additional histological staining using Periodic acid-Schiff and Masson’s trichrome were performed on 8 and 24 h NBF, Bouin’s and Form-Acetic fixed samples to assess the compatibility of the new fixative with stains. On ovarian tissue fixed for both 8 and 24 h in NBF and Form-Acetic, immunohistochemistry (IHC) studies to detect FOXO3a, FoxL2, collagen IV, laminin and anti-Müllerian hormone (AMH) proteins were performed in addition to the terminal deoxynucleotidyl transferase nick end labelling (TUNEL) assay to determine the compatibility of Form-Acetic fixation with types of histological molecular analyses.MAIN RESULTS AND THE ROLE OF CHANCEFixation in Form-Acetic improved ovarian tissue morphology compared to NBF from all three species and either slightly improved or was comparable to Bouin’s for human, mouse and sheep tissues. Form-Acetic was compatible with H&E, Periodic acid-Schiff and Masson’s trichrome staining and all proteins (FOXO3a, FoxL2, collagen IV and laminin and AMH) could be detected via IHC. Furthermore, Form-Acetic, unlike NBF, enabled antigen recognition for most of the proteins tested without the need for antigen retrieval. Form-Acetic also enabled the detection of damaged DNA via the TUNEL assay using fluorescence.LARGE SCALE DATAN/ALIMITATIONS, REASONS FOR CAUTIONIn this study, IHC analysis was performed on a select number of protein types in ovarian tissue thus encouraging further studies to confirm the use of Form-Acetic in enabling the detection of a wider range of protein forms in addition to other tissue types.WIDER IMPLICATIONS OF THE FINDINGSThe simplicity in preparation of Form-Acetic and its superior preservative properties whilst enabling forms of histological molecular analyses make it a highly valuable tool for studying ovarian tissue. We, therefore, recommend that Form-Acetic replaces currently used fixatives and encourage others to introduce it into their research workflow.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by the Oxford Medical Research Council Doctoral Training Programme (Oxford MRC-DTP) grant awarded to B.D.B. (Grant no. MR/N013468/1), the Fondation Hoffmann supporting R.A. and the Petroleum Technology Development Fund (PTDF) awarded to B.V.A.

Analysis of surgical pathology specimens by histological techniques including immunohistochemistry (IHC) assays is a mainstay of disease diagnosis in humans. Neutral buffered formalin (NBF) is currently the primary fixative used, but its use is not without risks due to toxicity and carcinogenicity. Several glyoxal-based fixatives have been commercially produced, are considered safer alternatives to NBF, and produce histochemical staining results comparable to that of tissues fixed in NBF. However, previous studies evaluating IHC assay results in tissues fixed in NBF and glyoxal solutions have indicated mixed results. This study demonstrated that while tissues fixed in NBF were slightly superior to tissues fixed in glyoxal solutions among the 34 antibodies assayed with IHC, all fixative solutions produced results compatible for use in an anatomic pathology laboratory.

Platelets, lymphocytes, and megakaryocytes, specifically processed for the intracellular detection of antigens, were studied by indirect immunofluorescence techniques using monospecific antibodies directed against factor VIII-related antigen (F-VIII-RA). Specific staining was observed in platelets of the peripheral blood from normal individuals and from patients with haemophilia A, and in megakaryocytes and platelets of bone marrow from normal subjects. The same cells studied in patients with von Willebrand’s disease were negative. No bone marrow biopsies were performed on patients with haemophilia A. Our results indicate that F-VIII-RA is localized in megakaryocytes and platelets of normal subjects; the possible role of this F-VIII-RA in platelet function is discussed.

Utility and Patterns of Use of PET/CT and Bone Marrow Biopsy for Staging in Non-Hodgkin Lymphoma in the Clinical Setting: A Retrospective Analysis Using the LEO Database

A Regenerative Role for Bone Marrow Following Experimental Colitis: Contribution to Neovasculogenesis and Myofibroblasts

The purpose of this study was to determine the effect of formalin fixation on the immunohistochemical detection of porcine reproductive and respiratory syndrome (PRRS) viral antigen in lungs of experimentally and naturally infected pigs. In separate trials, five 24-day-old pigs and six 10-day-old pigs were housed as separate groups in isolation and inoculated intranasally with 10(5.5) TCID50 of an isolate of PRRS virus (PRRSV; P129). The older and younger pigs were euthanatized at 7 and 10 days post inoculation (dpi), respectively. At necropsy, all pigs had gross and microscopic lung lesions typical of PRRS, and PRRSV was isolated from all pigs. To insure uniform fixation, lungs from each pig were cut into 1-cm-thick slices and immersed into 10% neutral-buffered formalin. After fixation in formalin for 8 hours or 1, 2, 3, 5, 6, 8, 10, and 15 days, 3 lung sections from some or all pigs were processed for histological examination using routine methods. Immunohistochemical staining for PRRSV antigen was positive at the following times (days unless otherwise stated) after fixation (percentage of pigs staining positive for PRRSV in parentheses): 8 hours (100); 1 (100); 2 (100); 3 (80); 5 (33); and 6, 8, 10, and 15 (0-all negative). To further evaluate the effects of formalin fixation on PRRSV immunodetection, 31 field cases of PRRS were selected for immunohistochemistry (IHC). Over a 3-month period, submitted cases were selected from the Purdue University Animal Disease Diagnostic Laboratory, W. Lafayette, Indiana, for IHC if 1) the clinical history included respiratory disease, 2) PRRSV was isolated from lung and/or serum from the submitted pigs or tissues, 3) at least 1 section of lung fixed in 10% neutral-buffered formalin was submitted for IHC, and 4) the duration of fixation could be accurately determined from the case history. Of the 31 PRRSV-infected pig cases meeting the selection criteria, 23 were fixed in formalin for 4 days or less. Twenty-one of these 23 (91%) were positive by IHC. Two of 8 cases fixed for greater than 4 days (25%) were positive by IHC. In practical terms, 1-day shipping of fixed samples to a laboratory followed by routine tissue processing within a laboratory should not adversely affect immunohistochemical detection of PRRS viral antigen. But a delay in shipping or processing of more than 2 days could reduce or prevent the detection of PRRS viral antigen by IHC.

Ethylene Diamine Tetra Acetic Acid (EDTA) Decalcification of Paediatric Bone Marrow Trephines In a Diagnostic Laboratory

Assessment of bone marrow is most commonly performed qualitatively in the spine or other large long bones. The craniofacial bones are less ideal for bone marrow analysis because of the relatively small bone marrow volume. Because patients with SCD often undergo repeated brain imaging to evaluate for cerebral vaso-occlusive disease, quantitative assessment of craniofacial bone marrow is a reasonable possibility in these patients. The purpose of this study was to investigate specific sickle cell disease changes in craniofacial bone marrow quantitatively by analyzing T1, T2, and secular-T2 relaxation times and volume with the use of quantitative MRI. Fourteen patients with SCD and 17 control subjects were imaged with the mixed TSE pulse sequence at 1.5T. The craniofacial bones were manually segmented by using 3D Slicer to generate bone marrow volumes and to provide T1, T2, and secular-T2 relaxation times. All subjects exhibited a bimodal T1 histogram. In the SCD group, there was a decrease in amplitude in the first T1 peak and an increase in amplitude in the second T1 peak. The first T1 peak showed a significant increase in relaxation time compared with control subjects (P < .0001), whereas there was no significant difference in the second T1 peak. T2 and secular-T2 relaxation times were significantly shorter in the SCD group (T2, P < .0001; secular-T2, P < .0001). Increasing numbers of blood transfusions resulted in a decrease in T2 and secular-T2 times. Patients with SCD exhibited a larger bone marrow volume compared with control subjects, even after standardization. Patients with SCD exhibited significant quantifiable changes in the craniofacial bone marrow because of failure of red-to-yellow marrow conversion and iron deposition that can be identified by qMRI relaxometry and volumetry. Both qMRI relaxometry and volumetry may be used as noninvasive tools for assessment of disease severity.

Expansion of Canine Bone Marrow-Derived Endothelial Progenitor Cells and Dynamic Observation

Tissue-Specific Effects of the Nuclear Factor κB Subunit p50 on Myocardial Ischemia-Reperfusion Injury

Introduction: The bone marrow examination is an essential investigation in the diagnosis and management of many haematological disorders. The integration of all investigations, including peripheral blood analysis, bone marrow aspirate, and trephine biopsy findings, along with supplementary tests such as immunophenotyping, cytogenetic analysis, and molecular genetic studies, is crucial for arriving at a final diagnosis. Aim: To assess the presence of reticulin fibres in bone marrow biopsy sections in haematological malignancies, to evaluate the grade of BMF associated with haematological malignancies and to assess the role of angiogenesis using IHC markers in various haematological malignancies. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at the National Institute of Pathology, Safdarjung Hospital, New Delhi, India in 2009 for a duration of 18 months. Thirty-eight patients with a diagnosis of Acute Myeloid Leukaemia (AML), Acute Lymphoblastic Leukaemia (ALL), Chronic Myeloid Leukaemia (CML), and Chronic Lymphoproliferative Disorder (CLPD) were studied. Bone marrow biopsies were taken, fixed in 10% formalin, and decalcified in 10% Ethylene Diamine Tetraacetic Acid (EDTA). Routine paraffin embedding was performed, and serial sections of 4 µm were obtained on poly-L-lysine-coated slides for Immunohistochemistry (IHC) {Vimentin, Vascular Endothelial Growth Factor (VEGF), CD-34, Smooth Muscle Actin (SMA)}. The presence of reticulin fibres in the bone marrow biopsy sections was assessed using two special stains: Gomori’s Silver Impregnation and Masson’s Trichrome. Fibrosis was quantified according to the Baurmeister 0-4 grading system of Bone Marrow Fibrosis (BMF). Results: The results of the present study suggest that Endothelial to Mesenchymal Transition (EndMT) may play a role in the pathogenesis of BMF. Various grades of fibrosis were observed, with 15 cases (39.47%) in Grade 3, followed by 11 cases (28.95%) in Grade 2, 8 cases (21.05%) in Grade 1, and 4 cases (10.53%) in Grade 4. Conclusion: BMF was a significant finding even in the early stages of the majority of the lesions studied and was closely linked with angiogenesis. This study showed that angiogenesis plays an important role in the pathogenesis of haematological neoplasms and that VEGF is a prominent stimulus in the majority of these disorders. Additionally, this study suggests that EndMT has a possible role in the pathogenesis of BMF.Introduction: The bone marrow examination is an essential investigation in the diagnosis and management of many haematological disorders. The integration of all investigations, including peripheral blood analysis, bone marrow aspirate, and trephine biopsy findings, along with supplementary tests such as immunophenotyping, cytogenetic analysis, and molecular genetic studies, is crucial for arriving at a final diagnosis. Aim: To assess the presence of reticulin fibres in bone marrow biopsy sections in haematological malignancies, to evaluate the grade of BMF associated with haematological malignancies and to assess the role of angiogenesis using IHC markers in various haematological malignancies. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at the National Institute of Pathology, Safdarjung Hospital, New Delhi, India in 2009 for a duration of 18 months. Thirty-eight patients with a diagnosis of Acute Myeloid Leukaemia (AML), Acute Lymphoblastic Leukaemia (ALL), Chronic Myeloid Leukaemia (CML), and Chronic Lymphoproliferative Disorder (CLPD) were studied. Bone marrow biopsies were taken, fixed in 10% formalin, and decalcified in 10% Ethylene Diamine Tetraacetic Acid (EDTA). Routine paraffin embedding was performed, and serial sections of 4 µm were obtained on poly-L-lysine-coated slides for Immunohistochemistry (IHC) {Vimentin, Vascular Endothelial Growth Factor (VEGF), CD-34, Smooth Muscle Actin (SMA)}. The presence of reticulin fibres in the bone marrow biopsy sections was assessed using two special stains: Gomori’s Silver Impregnation and Masson’s Trichrome. Fibrosis was quantified according to the Baurmeister 0-4 grading system of Bone Marrow Fibrosis (BMF). Results: The results of the present study suggest that Endothelial to Mesenchymal Transition (EndMT) may play a role in the pathogenesis of BMF. Various grades of fibrosis were observed, with 15 cases (39.47%) in Grade 3, followed by 11 cases (28.95%) in Grade 2, 8 cases (21.05%) in Grade 1, and 4 cases (10.53%) in Grade 4. Conclusion: BMF was a significant finding even in the early stages of the majority of the lesions studied and was closely linked with angiogenesis. This study showed that angiogenesis plays an important role in the pathogenesis of haematological neoplasms and that VEGF is a prominent stimulus in the majority of these disorders. Additionally, this study suggests that EndMT has a possible role in the pathogenesis of BMF.

Correlation of Serum Free Light Chains and Bone Marrow Plasma Cell Infiltration in Multiple Myeloma.

Microwave processing has progressed into a promising procedure for use in the clinical electron microscopy laboratory. In striving for faster turn-around-time in the clinical patient environment, the laboratory microwave has become a very exciting tool. The development of microwave technology enhances the pathologists’ ability to diagnose quickly without compromising quality. This laboratory's patient sample base is primarily renal biopsies. Tumors and other tissue abnormalities are also diagnosed. Animal and human renal tissue were used for experimentation with the microwave processing protocol. With the need for consistency between the existing resin of choice and standard processing protocol, procedures were developed with these criteria in mind. The standard electron microscopy processing protocol for this laboratory is fixation in either 10% neutral buffered formalin (NBF) or 4% buffered gluteraldehyde followed by post-fixation with 1% osmium tetroxide for 1 hour. The dehydration is performed with gradients of 50% to 100% ethanol followed by a transition solvent of propylene oxide into resin infiltration and polymerization.