Axillary Sweat Gland Carcinoma Versus Amelanotic Malignant Melanoma

A technique for immunoelectron microscopy is described whereby tissue is embedded in large (6 × 12 mm) plastic blocks and reembedded (“popped off”) directly from semithin (3-μm) sections for thin sectioning. This technique is particularly useful in locating relatively sparse cells or tissue structures. Three acrylic plastics were evaluated: Lowicryl K4M, LR Gold, and LR White. Results indicated excellent ultrastructural morphologic preservation and retention of antigenicity with the first two plastics both comparable to conventional methods of processing. Lowicryl and LR Gold were successfully adapted to the large block pop-off technique. Technical problems were encountered with LR White.     

Tissue distortion in three-dimensional reconstruction of wax or plastic embedded microscopic structures

Three-dimensional reconstruction at the light microscopic level depends on obtaining reliable serial sections without "distortion" i.e., expansion and compression during section preparation. We have studied the extent of such distortion in serial sections from paraffin and resin embedded blocks of brain, kidney, liver and lung, using an IBAS 2000 Image Analyser. We found that, taking the uncut block as 100%, the section area, perimeter and minimum diameter varied by no more than 8%, except for the lung sections which varied up to 14%. There was no progressive compression due to knife bluntening. Resin sections also varied up to 8% (16% for lungs) but in addition creasing was a problem. We conclude that, provided the serial sectioning is carefully standardised for block shape and orientation, floating out temperature and time, serial paraffin sections are more suitable for three dimensional reconstruction than resin sections.     

The number of neurons in dorsal root ganglia L4–L6 of the rat

The number of neurons in the dorsal root ganglia L4–L6 of the rat was determined because published data are inconsistent and in general incompatible with the number of afferent axons in the sciatic nerve. Nucleoli were counted in serial sections; epoxy-resin sections 3 μm thick, or paraffin sections 5 μm thick, or unstained 12-μm paraffin sections of osmicated tissue were used. Correction factors for split and multiple nucleoli were obtained by counting nucleolar profiles in consecutive sections of identified cells. Dividing the number of nucleolar profiles into the number of cells gave the factor by which the counts of nucleolar profiles had to be multiplied to obtain the number of neurons. The ganglia L4, L5, and L6 contained about 12,000, 15,000 and 14,000 neurons, respectively, when resin sections were used. The standard deviation for the average of 41,000 neurons in the three ganglia was 8% of the mean value. The results compare well with the number of dorsal root fibers, and with the fact that the sciatic nerve at midthigh, to which less than half of the neurons connect, contains 19,000 afferent axons. The data obtained from the paraffin series were 23% smaller, but still considerably higher and less variable than all previously reported data. The main problem with stained paraffin sections was that most small neurons had multiple nucleoli attached to the membrane of the nuclei, which only measured 10 μm in diameter. The nucleoli often projected into the dark cytoplasm and were difficult to identify.     

A technique for the evaluation of failed fallopian tube ligation with metal clips

The evaluation of fallopian tubes after failed tubal ligation can be difficult because conventional histopathological techniques are unable to section the metal clips when in situ. Once the clips have been removed, any evidence of tube patency is lost. This report describes a technique of embedding and sectioning that enables sections to be made while the metal clips are still in situ. This is a modification of a method first described to embed mineralised bone and involves the use of plastic embedding and a diamond saw. Using this technique, a permanent record is made of the tube location and patency.

Key Words: sterilisation failure • fallopian tubes • contraception

     

Antigen localization in immunoperoxidase-stained plastic-embedded soft tissues

Immunoperoxidase stains were performed on normal and neoplastic tissue from prostate, colon, thyroid, lung, nerve, uterus, and placenta embedded in both plastic (glycolmethacrylate [GMA]) and paraffin. Positive results in plastic section were obtained for carcinoembryonic antigen (CEA), keratin, epithelial membrane antigen (EMA), thyroglobulins, S-100, prostate-specific antigen, human chorionic gonadotrophin (HCG), and beta-HCG. More delicate staining with more precise localization of antigens is noted. Superior (paraformaldehyde) fixation and cold processing followed by GMA polymerization (4 degrees C) allow for optimum antigen survival. After fixation, tissue processing involves a series of 0.1 mol/L phosphate buffer rinses with sucrose and ammonium chloride in a conventional dip-and-dunk processor placed in a 4 degrees C cold room. Acetone dehydrations are used before GMA infiltration, cold polymerization, and sectioning. Before immunoperoxidase staining, the plastic section is digested in .25% bovine trypsin for ten minutes. The immunoperoxidase methods described can be useful when small biopsies are routinely embedded in plastic to obtain improved histologic (hematoxylin-eosin) sections. There may also be research applications in quantifying antigen expression in benign, dysplastic, and neoplastic tissues by examining the stains under high power.     

Immunoreactive β-endorphin and acth in the same neurons of the hypothalamic arcuate nucleus in the rat

Immunoreactive ACTH and β-endorphin (β-End) were localized in the brain and pituitaries of normal and colchicine-treated rats, using the immunoperoxidase method at the light microscopic level. On adjacent serial 5-μm paraffin sections of anterior pituitaries, both ACTH and β-End could be found in the same cells. On adjacent 5-μm paraffin sections of brains of colchicine-treated rats, both ACTH and β-End could be found in the same perikarya of hypothalamic arcuate nucleus neurons. It appeared that all perikarya containing β-End contained ACTH as well, suggesting that neurons producing β-End also produce ACTH. Pathways of ACTH fibers corresponded to pathways of β-End fibers. These findings suggest that the synthesis, and transport, of ACTH and β-End are linked in the brain as well as in the pituitary, possibly through a common precursor.     

Localization of cytomegalovirus DNA in plastic-embedded sections by in situ hybridization. A methodologic study.

The use of in situ hybridization for the identification of specific nucleic acid sequences in tissue sections has the potential for broad application in pathology. Although this technique has been successfully applied to routine paraffin sections, there have been few studies of the application of in situ hybridization to plastic-embedded tissue sections. The authors adapted techniques developed for paraffin sections to take advantage of the potential for improved morphology and more precise localization inherent in the plastic sections. A commercially available biotinylated DNA probe specific for the cytomegalovirus to develop a practical method for detection of nucleic acid sequences in plastic-embedded tissues was used. Using plastic sections, cytomegalovirus DNA sequences could readily be identified with precise localization of the virus and superb histology.     

Modification of Brain Processing Techniques: Tissue Embedding in Glycol Methacrylate and Stain Modifications

Abstract

Increased interest in quantitation of the histopathological changes in a variety of neurological disorders (including neurodegenerative disease such as Alzheimer's disease) continues in an attempt to develop specific clinical-histopathological correlations. Most previous efforts at quantitation have used paraffin embedded sections of brain tissue, although plastic embedded sections have recently become a preferable alternative because they provide greatly reduced tissue shrinkage and distortion during processing, and greater clarity and improved resolution to the tissue sections. We have developed techniques for glycol methacrylate embedding and sectioning of brain tissue blocks on a standard histology laboratory microtome. In addition, we have modified routine diagnostic and investigational neurohistological stains for use in glycol methacrylate embedded brain sections, including hematoxylin and eosin, modified Bielschowsky stain, Jamarri silver technique, Einarson's Nissl stain, gallocyanin-Darrow red myelin stain, and the thioflavine-S-hematoxylin stain. The use of plastic embedded sections with appropriate stains will permit critical histopathological evaluation of nervous system tissue from patients with a variety of neurological disorders. (J Histotechnol 12:201, 1989)     

Amplification of tissue by construction of tissue microarrays.

Tissue microarrays are a method of relocating tissue from conventional histologic paraffin blocks in a manner that tissue from multiple patients or blocks can be seen on the same slide. This is done by using a needle to biopsy a standard histologic section and placing the core into an array on a recipient paraffin block. This technique allows maximization of tissue resources by analysis of small core biopsies of blocks, rather than complete sections. Using this technology, a carefully planned array can be constructed using cases from pathology tissue block archives, and a 20-year survival analysis can be done on a cohort of 600 or more patients using only a few microliters of antibody in a single experiment. Furthermore, this cohort can be analyzed thousands of times with different reagents as a result of judicious sectioning of the array block. This review describes this process and discusses the issues of representative sampling in heterogeneous lesions, the issue of antigen preservation, and some technical strategies and methods of array construction. In summary, this technique can provide a highly efficient, high-throughput mechanism for evaluation of protein expression in large cohorts. It has the potential for allowing validation of new genes at a speed comparable to the rapid rate of gene discovery afforded by DNA microarrays.     

Whole-specimen histopathology: a method to produce whole-mount breast serial sections for 3-D digital histopathology imaging

AIMS: To develop a method for preparing diagnostic-quality, whole-mount serial sections of breast specimens while preserving 3-D conformation. This required supporting the fresh specimen prior to breadloafing and refining the conventional tissue processing method. The overall goal is to use digital images of whole-specimen histopathology to improve the estimation of extent of disease. METHODS AND RESULTS: To maintain a 3-D conformation, the specimen is suspended in 3.5% agar at 55 degrees C. The block is sliced at 5-mm intervals. Sectioning is performed after extended fixation in 4% formaldehyde from paraformaldehyde in 0.1 m Millonig's buffer, followed by paraffin processing using a non-routine schedule and extended paraffin infiltration. Whole-mount serial breast sections are produced with features of equal or superior quality to that which can be achieved using conventional methods. The method is compatible with some immunohistochemical stains but requires further optimization for others. CONCLUSIONS: The technique is currently suitable for research applications. With the reduction in processing time achievable with microwave-assisted processing, there is the potential for its use as a routine clinical method. This tool may improve the accuracy of margin estimates and identification of multifocality in breast cancer; further evaluation is necessary.     

"Pop-off" technic. The ultrastructure of paraffin-embedded sections

Stained paraffin embedded sections sometimes contain a precise area that warrants further investigation at an ultrastructural level. A technic is described whereby an area in question may be reembedded into plastic and sectioned for examination under the electron microscope. The decoverslipped paraffin section is "popped-off" into an inverted BEEM capsule. Suspected viral inclusions in sections may be identified or ruled out with this technic. Special stains, especially heavy metal applications, not able to be utilized in conventional plastic embedding may be reembedded into plastic. The metallic granules may be visualized ultrastructurally without further grid staining. This method is especially helpful for cell smears and cell monolayers since they may be the only material available for study. Although ultrastructural detail is often poor, one does have the ability to study the identical section under both the light and the electron microscopes.     

Techniques used to assess intussusceptive angiogenesis: A systematic review

Intussusceptive angiogenesis (IA) is an important physiological form of angiogenesis in which an existing vessel splits in two by the formation of an intraluminal tissue pillar. The presence of these intraluminal pillars form the hallmark of ongoing IA in growing vascular beds. However, their visualization is technically challenging. The goal of this systematic review was to investigate which techniques are being used to identify intraluminal pillars and to formulate important points to keep in mind when studying IA. A systematic literature search resulted in 154 evaluated articles of which the majority (65%) provided sufficient data to unambiguously demonstrate the presence of intraluminal pillars. Scanning electron microscopy imaging of vascular corrosion casts and serial sectioning of ultrathin sections are the most used techniques. New methods such as serial block face scanning electron microscopy and micro computed tomography (μCT) are gaining importance. Moreover, our results indicate that IA was studied in a variety of animals and tissues. IA is a biologically very relevant form of angiogenesis. Techniques to visualize intraluminal pillars need to have a minimal resolution of 1 μm and should provide information on the 3D-nature of the pillars. Optimally, several techniques are combined to demonstrate ongoing IA.     

Effects of colchicine on the shape of chick neuroepithelial cells during neurulation

We have analyzed the effects of colchicine on the cell shapes in chick neuroepithelium. Cell shapes were ascertained by the position of the nucleus in plastic serial sections. We tested three colchicine doses (5 X 10(-5) M, 5 X 10(-6) M, and 5 X 10(-7) M) by two experimental treatments (in ovo and in vitro). Colchicine treatment in vitro is always effective in depolymerizing microtubules of neuroepithelial cells and reduces the percentages of wedge-shaped cells in the median area of neuroepithelium. The same effect can be observed when the embryos are treated with 5 X 10(-5) M or 5 X 10(-6) M colchicine in ovo. A concentration of colchicine of 5 X 10(-7) M in ovo cannot disrupt microtubules in stage 8 and stage 10 embryos, and the percentage of wedge-shaped cells is the same as that of the untreated cells. In stage 6 embryos this colchicine dose effects the microtubules and the percentages of wedge-shaped cells. These facts are interpreted in respect to variations in microtubular resistance to microtubular-disrupting agents that are shown by the neuroepithelial cells from different developmental stages.     

塑料包埋技术在骨组织研究中的应用

目的研究塑料包埋技术制作的不脱钙硬组织切片,确定制作的关键步骤及用于骨组织研究的优点。方法选取狗胫骨节段或带有金属种植体的骨材料塑料包埋,LeicaSP1600切片机（德国）切片,用苦味酸品红染色观察,并与常规石蜡包埋相比较。结果不脱钙骨组织经塑料包埋技术处理后,可清楚地观察类骨质形成、多孔材料及种植体周围骨组织的整合程度。与常规石蜡包埋相比,染色层次分明,组织移位形变小。结论应用规范塑料包埋技术制作不脱钙硬组织切片,更有利于行骨形态计量分析以及材料与骨整合的研究。     

Demonstration of distinct antigenic profiles of small B-cell lymphomas by paraffin section immunohistochemistry.

The immunoperoxidase technique was used with antibodies against B-cell-associated antigens, including CD20, CD79a, CD10, CD23, CD43, cyclin D1, bcl-2, and kappa and lambda immunoglobulin light chains on formalin-fixed and B5-fixed tissue sections of follicular, small lymphocytic, mantle cell, and marginal zone lymphomas. Results obtained with paraffin section immunohistochemistry for CD20, CD10, CD23, and kappa and lambda light chains were compared with results obtained with flow cytometry or frozen section immunohistochemistry. Cells in all of the lymphoma types were positive for CD20 and CD79a. The antigenic profiles of the B-cell lymphomas demonstrated in paraffin sections were lymphoma type distinctive. Intrafollicular lymphocytes in follicular lymphomas were positive for CD10 and bcl-2. Small lymphocytic lymphomas expressed CD43 and CD23 and were negative for CD10 and cyclin D1. Mantle cell lymphomas characteristically expressed CD43 and cyclin D1 and were negative for CD23 and CD10. Marginal zone lymphomas were negative for CD23, CD10, and cyclin D1. All of the antibodies performed better in B5-fixed tissues, but formalin-fixed tissue immunophenotypes were always similar to those obtained on the B5-fixed tissue. These results were possible using well-fixed tissue, various antigen retrieval strategies, paraffin section reactive primary antibodies, and sensitive detection systems. Paraffin section immunohistochemistry on sections of routinely fixed tissue can be used similarly to flow cytometry and frozen section immunohistochemistry when classifying the lymphomas of small B lymphocytes.     

Silver Labeling of Alzheimer Neurofibrillary Changes and Brain β-Amyloid

Abstract

Alzheimer neurofibrillary changes and brain β-amyloid can be stained selectively by silver impregnation on tissue sections and (in the case of neurofibrillary proteins) on sodium dodecyl sulfate-polyacrylamide gels. The stain can be applied to frozen sections of tissue from 10–150 μm thick, to similarly thick polyethylene glycol sections, or to 5–15 μm thick paraffin sections. The technique can also be applied to routinely fixed autopsy material. The technique takes advantage of the physical development of nucleation sites, thereby permitting tight control of the entire procedure. It is less expensive than immunocytochemical techniques, and facilitates processing of large numbers of sections through entire hemispheres of the human brain. (The J Histotechnol 16:335, 1993)     

A simplified plastic embedding and immunohistologic technique for immunophenotypic analysis of human hematopoietic and lymphoid tissues.

Routine fixation and paraffin embedding destroys many hematopoietic and lymphoid differentiation antigens detected by flow cytometry or frozen section immunohistochemistry. On the other hand, morphologic evaluation is difficult in flow cytometric or frozen section studies. A simplified three-step plastic embedding system using acetone-fixed tissues embedded in glycol-methacrylate (GMA) resin has been found to provide both excellent morphologic and antigenic preservation. With our system, a wide variety of antigens are detected in plastic sections without trypsinization or prolonged embedding procedures; pan-B (CD19, CD22), pan-T (CD7, CD5, CD3, CD2), T-subset (CD4, CD8, CD1, CD25) markers as well as surface immunoglobulin and markers for myeloid and mononuclear-phagocyte cells are preserved. In summary, modifications of plastic embedding techniques used in this study simplify the procedure, apparently achieve excellent antigenic preservation, and facilitate evaluation of morphologic details in relation to immunocytochemical markers.     

一种基于大鼠颈髓连续切片的计算机三维重建方法

目的 以个人计算机(PC)为平台,探讨一种基于大鼠颈髓切片进行脊髓三维重建方法.方法 制作正常SD大鼠颈髓节段包埋蜡块,于颈髓标本四周进行外定位标记,Leica石蜡切片机进行连续横断切片,每切3张,用CANON数码相机对蜡块中的颈髓标本及其外定位标记进行摄片,获得连续切片图像.所得图像进行排序,裁切,转换为灰度图像并进行背景不均匀校正后,利用3D-DOCTOR软件对每张图像上的颈髓、颈髓灰质及定位孔进行边缘提取,利用定位孔对连续图像进行自动配准,三维表面重建后在PC机上进行任意角度观察、切割和测量.结果 利用大鼠颈髓连续切面图像重建得到大鼠颈髓白质和灰质,并对其进行测量,获得了表面积和体积等数据.结论 利用石蜡包埋和"硬"定位技术可以获得颈髓节段连续横断切面图像,进行三维重建并对重建结构进行自由观察和测量.     

Visualisation of three-dimensional microcracks in compact bone

Microdamage in bone contributes to the loss of bone quality in osteoporosis and is thought to play a major role in both fragility and stress fractures (Schaffler et al. 1995). In this study, in vivo microcracks in human ribs were bulk-stained in basic fuchsin and viewed in longitudinal section and in 3 dimensions using 2 different computer-based methods of reconstruction: (1) serial sectioning of methylmethacrylate embedded sections using a sledge macrotome and identification of microcracks using UV epifluorescence followed by computerised reconstruction of microcracks using software and (2) laser scanning confocal microscopy of thick sections followed by reconstruction of microcracks into a 3-D image. The size and shape of microcracks were found to be similar using both techniques. Both techniques of reconstruction showed microcracks to be approximately elliptical in shape. From the serial sectioning reconstructions (n = 9), microcracks were found to have a mean length of 404±145 m (mean± S.D. ) (in the longitudinal direction) and mean width of 97±38 m (in the transverse direction). Using epifluorescence microscopy, 92 microcracks were identified; mean microcrack length was 349±100 m in the longitudinal direction. This was consistent with other results (Burr & Martin, 1993) and with the theoretical prediction of an elliptical crack shape with aspect ratio (longitudinaltransverse) of 51 deduced from analysis of random 2-D sections (Taylor & Lee, 1998). The results obtained provide new data on the nature of microcracks in bone and the method has the potential to become a useful tool in the calculation of stress intensity values which indicate the probability of an individual microcrack propagating to cause a stress or fragility fracture.     

塑料包埋结合四环素荧光标记制作不脱钙骨组织切片的实验研究

目的探讨塑料包埋技术结合四环素荧光标记制作不脱钙骨组织切片的关键步骤及应用。方法选取四环素荧光标记的兔股骨进行塑料包埋,Leica SP 1600切片机切片,荧光显微镜观察后用苦味酸品红染色,并与常规石蜡包埋切片相比较。结果四环素荧光标记不脱钙骨组织经塑料包埋技术处理后,可清楚地观察类骨质形成、植入体及周围骨组织的整合程度,与常规石蜡包埋相比,染色层次分明,组织移位形变小。结论应用塑料包埋技术制作四环素荧光标记不脱钙骨组织切片,有利于行骨形态计量分析以及植入体与骨整合的研究。