Experimental lesions in rats corresponding to advanced human asbestosis

Rats inhaling chrysotile asbestos developed a progressive interstitial fibrosis similar in most respects to human asbestosis. The earliest lesions were focal deposits of fibrous tissue in the walls of respiratory bronchioles and alveolar ducts. Later alveolar septa between adjacent bronchioles became progressively thickened to produce lesions with similarities to human honeycombing. The thickened septa between alveoli or "micro-honeycomb" spaces were mainly surfaced with cuboidal epithelial cells although some spaces lined by ciliated columnar epithelium were also found. Transmission electron microscopy of these advanced lesions showed that the cuboidal epithelial cells retained most of the characteristics of type 2 pneumocytes but that they frequently exhibited apical cytoplasmic blebs normally associated with the apocrine secretion of Clara cells. Columnar cells exhibited all stages from fully cilitated to cells with only an occasional cilium among the normal cell surface microvilli. Alveolar or micro-honeycomb spaces frequently contained clusters of pulmonary macrophages with their surface processes interdigitated but with no signs of fusion to giant cells. At more than 18 months after the end of dust inhalation these macrophages contained no chrysotile asbestos. The basement membranes beneath the epithelial layers of thickened septa were irregular and often convoluted as well as being much thicker than normal. Microscopic deposits of calcification were frequently found within the basement membrane material. Some thickened septa were relatively acellular, consisting mainly of masses of collagen fibrils but others were cellular and contained many macrophages, fibroblasts, plasma cells and mast cells. In these advanced lesions extremely little chrysotile asbestos was found and this was present in two sites only. Some chrysotile, always as individual fibrils and usually of short length, was present among collagen fibrils in areas of fibrosis and some was present within the thickened basement membranes.     

Scanning and transmission electron microscope observations on human gallbladder epithelium

Summary The early development of the human gallbladder epithelium was studied in 25 foetuses with crown-rump (CR) lengths from 6.0 to 22.5 cm by light and scanning and transmission electron microscopy. The PAS-reaction was used to locate cellular mucosubstances.The development could be devided into previllous and villous stages by light microscopy. The incipient formation of villi was observed in the present material at the 12.5 cm stage.Electron microscopically, three stages of development in the gallbladder epithelial cells were noticed. In the first stage, only one epithelial cell type was found. The microvilli were undeveloped, and there were no secretory granules in the epithelial cells.In the second stage, the epithelial cells contained secretory granules. The other characteristics of this stage were pseudopod-like projections on the apical cell surfaces and development of microvilli into a brush border-like structure.In the third stage, the epithelium showed the same zonal construction as that of the adult gallbladder. The apical surface of the epithelial cell was convex, and the microvilli were well developed. There were no pseudopod-like projections on the apical cell surface. The secretory granules were similar to those seen in the normal epithelial cells of the adult gallbladder. Degenerating cells were sometimes seen in this stage. The PAS-reaction was positive in the second and third stages.     

Synovial sarcoma--a misnomer.

For an evaluation of the putative histogenetic relationship of synovia and synovial sarcomas, normal synovia, villonodular synovitis, and synovial sarcomas were compared for their patterns of expression of intermediate filaments of keratin and vimentin type and epithelial membrane antigen and for lectin binding sites. The lining cells in both normal synovia and villonodular synovitis reacted with anti-vimentin antibodies, but not with antibodies to different types of keratins or epithelial membrane antigen. The cleft-lining cells in synovial sarcoma, on the other hand, showed only keratin positivity, and epithelial membrane antigen could also be detected in these cells. Nonneoplastic synovial lining cells bound peanut agglutinin (PNA), Ricinus communis agglutinin (RCA), soybean agglutinin (SBA), concanavalin A (Con A), and wheat germ agglutinin (WGA) conjugates, but not Ulex europaeus I lectin (UEA I). In contrast, the epithelial-like cleft lining cells in synovial sarcomas showed an apical cytoplasmic binding of PNA, UEA I, RCA, and SBA, and binding of WGA to the whole cytoplasm but did not bind Con A. The distinct differences between synovial lining cells and synovial sarcoma cells speak against synovial cell features in synovial sarcoma. These results indicate that synovial sarcoma is a carcinosarcomalike tumor with true epithelial differentiation, and the term "synovial sarcoma" apparently is a misnomer that should be abandoned.     

HUMAN NORMAL AND NEOPLASTIC ADRENOCORTICAL CELLS IN TISSUE CULTURE OBSERVED BY SCANNING ELECTRON MICROSCOPY

Human normal and neoplastic adrencortlcal cells were Incubated under stimulation with ACTH and observed by scanning electron microscopy. Cultured normal adrenocortical cells gathered into small clusters, each cell of which had a polarity or orientation evidenced by two different aspects. In one aspect, the cell surface rounded up and microvilli protruded vertically. Pits were found among or close to the groups of microvilli. In the other aspect, the cell surface was flattened and well-developed microvilli ran horizontally. These two aspects of the cultured cells were thought to correspond to the cell surface facing the intercellular space and that facing the perisinusoidal space, respectively. In Incubated cell clusters of adrenocortical adenomas with Conn's syndrome, most cells lost this polarity or orientation and unstimulated cells existed as unit of the clusters, but all adenoma cells reacted to ACTH in the same manner. Microvilli were distributed unevenly. Filopodia were noticed in some cells. Bleb-like structures appeared frequently and some of them were about to be extricated from the cell surface as in normal adrenocortical cells. Adrenocortical adenomas with Cushing's syndrome showed remarkable responses to ACTH. Their cell surface was unclean with the adherence of fragmented cytoplasm and bleb-like structures. Horizontally running elongated microvilli were almost indistinguishable from collagen fibrils. Moreover, collagen fibrils were entangled with microvilli.     

Human normal and neoplastic adrenocortical cells in tissue culture observed by scanning electron microscopy

Human normal and neoplastic adrenocortical cells were incubated under stimulation with ACTH and observed by scanning electron microscopy. Cultured normal adrenocortical cells gathered into small clusters, each cell of which had a polarity or orientation evidenced by two different aspects. In one aspect, the cell surface rounded up and microvilli protruded vertically. Pits were found among or close to the groups of microvilli. In the other aspect, the cell surface was flattened and well-developed microvilli ran horizontally. These two aspects of the cultured cells were thought to correspond to the cell surface facing the intercellular space and that facing the perisinusoidal space, respectively. In incubated cell clusters of adrenocortical adenomas with Conn's syndrome, most cells lost this polarity or orientation and unstimulated cells existed as unit of the clusters, but all adenoma cells reacted to ACTH in the same manner. Microvilli were distributed unevenly. Filopodia were noticed in some cells. Bleb-like structures appeared frequently and some of them were about to be extricated from the cell surface as in normal adrenocortical cells. Adrenocortical adenomas with Cushing's syndrome showed remarkable responses to ACTH. Their cell surface was unclean with the adherence of fragmented cytoplasm and bleb-like structures. Horizontally running elongated microvilli were almost indistinguishable from collagen fibrils. Moreover, collagen fibrils were entangled with microvilli.     

Synovial sarcoma: a review and update, with emphasis on the ultrastructural characterization of the nonglandular component.

Classic biphasic synovial sarcoma is usually not a problem in identification, whereas the monophasic spindle cell form continues to be a challenge in the differential diagnosis of spindle cell neoplasms. Most synovial sarcomas do not arise from a joint or tendon sheath, and by electron microscopy and immunohistochemistry they differ in several ways from nonneoplastic synovium. The cell of origin of synovial sarcoma is unknown, but certain features are rather consistently observed in the biphasic tumors and are useful in identifying monophasic samples. These features are apparent by immunohistochemistry and electron microscopy, both of which indicate early epithelial differentiation in the nonglandular component of the neoplasm. With immunohistochemistry, some of these cells stain for keratin. By electron microscopy, a gradient of differentiation from unclassifiable spindle cells to fully differentiated epithelial lining cells is demonstrable. A review and illustration of the ultrastructural characteristics in this spectrum of intermediate cells constitute the main emphasis of the article. The cells tend to be oval and polygonal; to be arranged in clusters surrounded by basal lamina or flocculent matrix; to have junctions, including tight junctions, and to form villuslike filopodia, true microvilli, canaliculi, and microlumina. This range of ultrastructural features is usually diagnostic of the nonglandular phase of synovial sarcoma.     

Synovial Sarcoma: A Review and Update,with Emphasis on the Ultrastructural Characterization of the Nonglandular Component

Classic triphasic synovial sarcoma is usually not a problem in identification, whereas the monophasic spindle cell form continues to be a challenge in the differential diagnosis of spindle cell neoplasms. Most synovial sarcomas do not arise from a joint or tendon sheath, and by electron microscopy and immunohistochemistry they differ in several ways from nonneoplastic synovium. The cell of origin of synovial sarcoma is unknown, but certain features are rather consistently observed in the biphasic tumors and are useful in identifying monophasic samples. These features are apparent by immunohistochemistry and electron microscopy, both of which indicate early epithelial differentiation in the nonglandular component of the neoplasm. With immunohistochemistry, some of these cells stain for keratin. By electron microscopy, a gradient of differentiation from unclassifiable spindle cells to fully differentiated epithelial lining cells is demonstrable. A review and illustration of the ultrastructural characteristics in this spectrum of intermediate cells constitute the main emphasis of the article. The cells tend to be oval and polygonal; to be arranged in clusters surrounded by basal lamina or flocculent matrix; to have junctions, including tight junctions, and to form villuslike filopodia, true microvilli, canaliculi, and microlumina. This range of ultrastructural features is usually diagnostic of the nonglandular phase of synovial sarcoma.     

Synovial Sarcoma: A Review and Update, with Emphasis on the Ultrastructural Characterization of the Nonglandular Component

Classic triphasic synovial sarcoma is usually not a problem in identification, whereas the monophasic spindle cell form continues to be a challenge in the differential diagnosis of spindle cell neoplasms. Most synovial sarcomas do not arise from a joint or tendon sheath, and by electron microscopy and immunohistochemistry they differ in several ways from nonneoplastic synovium. The cell of origin of synovial sarcoma is unknown, but certain features are rather consistently observed in the biphasic tumors and are useful in identifying monophasic samples. These features are apparent by immunohistochemistry and electron microscopy, both of which indicate early epithelial differentiation in the nonglandular component of the neoplasm. With immunohistochemistry, some of these cells stain for keratin. By electron microscopy, a gradient of differentiation from unclassifiable spindle cells to fully differentiated epithelial lining cells is demonstrable. A review and illustration of the ultrastructural characteristics in this spectrum of intermediate cells constitute the main emphasis of the article. The cells tend to be oval and polygonal; to be arranged in clusters surrounded by basal lamina or flocculent matrix; to have junctions, including tight junctions, and to form villuslike filopodia, true microvilli, canaliculi, and microlumina. This range of ultrastructural features is usually diagnostic of the nonglandular phase of synovial sarcoma.     

“Caveolated cells” characterized by deep surface invaginations and abundant filaments in mouse gastro-intestinal epithelia

Light and electron microscope examination of gastro-intestinal epithelia in the adult mouse revealed the widespread presence of a cell type characterized by deep surface invaginations or “caveolae” and, accordingly, called “caveolated cell.” The caveolated cells are scattered within the epithelia of stomach, small and large intestine; they have a narrow apex bordering the lumen and a wide base in contact with the basement membrane. In the light microscope, they display microvilli longer than in nearby cells; the cytoplasm is usually pale and contains an apical group of parallel fibrils, next to which are minute light spaces which may correspond to the caveolae. In the electron microscope, each fibril is found to be composed of a bundle of straight filaments, extending from the core of a microvillus down into the deeper portion of the supranuclear region; microtubules are often associated with these filaments. Filaments of a different type are arranged in bundles which go from desmosome to desmosome around the apical region of the cell. The caveolae are long and tortuous channels opening at the cell surface between the microvilli and extending deep into the cytoplasm. From the walls of caveolae, polyp-like structures project into the lumen. The heads of the polyps are believed to be released into this lumen where they appear as small spheres. These in turn may come out of the caveolae to appear between and next to the microvilli. Caveolated cells are not numerous, e.g., they make up less than 1% of the epithelial cells in the crypts of descending colon. They may be found in the intestinal crypts among poorly differentiated cells, and at the surface of stomach and intestine among fully differentiated cells. They appear to undergo renewal, but since they have not been seen in mitosis, they probably arise from the differentiation of some other epithelial cells.     

Synovial sarcoma: an immunohistochemical study

The immunohistochemical staining pattern of 18 cases of synovial sarcoma with two epithelial-specific monoclonal antibodies is described. This is compared with normal synovium, cases of giant cell tumour of tendon sheath (benign synovioma) and a variety of spindle celled sarcomas. Sixteen cases of synovial sarcoma showed staining of the epithelial component with at least one antibody. No staining was seen in normal synovium or in giant cell tumours of tendon sheath. A small number of malignant schwannomas contained groups of cells which stained positively whilst other spindle cell sarcomas either did not stain or showed 'cross-reaction' type staining only. These results add weight to the proposition that synovial sarcomas do not arise from normal synovium, despite their morphological similarities, but from mesenchymal connective tissue. It is also shown that immunohistochemical staining with anti-epithelial antibodies will emphasize the biphasic pattern of synovial sarcomas allowing their distinction from other sarcomas.     

Synovial sarcoma. Inter-relationship of the biphasic and monophasic subtypes.

In order to assess minimum diagnostic criteria for synovial sarcoma, particularly the monophasic variety, and the inter-relationship between the monophasic and biphasic types, 32 examples were studied histologically, immunohistochemically (26 cases), and ultrastructurally (13 cases). Of the six biphasic synovial sarcomas examined by electron microscopy, the spindle cell component did not show evidence of epithelial differentiation or resemble the epithelial phase, but did appear fibroblastic; no tumor cells transitional between the spindle and epithelial component were evident. In contrast, all of the seven monophasic lesions had ultrastructural growth patterns and some cellular features approximating the epithelial cells of the biphasic variant. In 11 biphasic synovial sarcomas, epithelial membrane antigen was detected in the glandular epithelium of all cases and cytokeratins in eight cases; in no case were these antigens detected in the spindle cell regions of biphasic lesions. Of the 15 monophasic synovial sarcomas, two were positive for cytokeratins and four for epithelial membrane antigen. Thus, the detection of epithelial markers either immunohistochemically or by electron microscopy (or both) should be the minimal diagnostic criteria for monophasic synovial sarcomas. Based on these findings, it is suggested that monophasic synovial sarcomas do not represent the spindle cell or "stromal" phase of biphasic synovial sarcomas, but are a poorly differentiated variant of the latter. As others have suggested, these tumors are, in fact, carcinosarcomas and carcinomas of the soft tissues and the designation synovial sarcoma is inappropriate for this tumor class.     

Gland and epithelium formation in vitro from epithelial cells of the human endometrium

As is often the case with cell culture, normal human endometrial epithelial cells show a low, squamous shape with flattened nuclei and lack three-dimensional morphology in in-vitro culture systems. Here we report the first well-differentiated epithelial culture system using basement membrane extracts (BME) from an Engelbreth-Holm-Swarm tumour (EHS tumour). In this model, BME regulated the reconstruction of glandular formation and subsequent reformation of the epithelium by epithelial cells. An electron microscopic study clearly indicated that there were two distinct types of cells grown on the substrate. The first, having a high columnar shape, formed the glandular epithelium, and the second, having a cuboidal shape, covered the surface of the BME. Study of epithelial reformation indicated that the regeneration of superficial epithelium could occur, following the development of the glandular formation, in a helix-like pattern. Total protein secretion was greater when the cells were grown on the BME than on plastic. Thus, normal human endometrial epithelial cells cultured on the BME assumed a phenotype and morphology characteristic of those in vivo.     

Renal epithelial neoplasms: the diagnostic implications of electron microscopic study in 55 cases

Several unsettled histogenetic, nosologic and diagnostic considerations for renal epithelial tumors may have ultrastructural ramifications. Yet, a comprehensive electron microscopic study of renal epithelial neoplasms, in light of the recent classification, is not available. The ultrastructural findings from fifty-five renal epithelial neoplasms [31 clear cell renal cell carcinomas (RCC), 11 papillary RCC, 5 chromophobe RCC, 3 sarcomatoid RCC and 5 oncocytomas] were correlated with their light microscopic appearance. Clear cell RCC showed long microvilli similar to the brush border of the normal proximal tubules, with abundant cytoplasmic lipid and glycogen. Papillary RCC showed variably sized microvilli, and small amounts of cytoplasmic lipid, but no glycogen. Chromophobe RCC showed many cytoplasmic vesicles and abnormal mitochondria, with rare short and stubby microvilli. Renal oncocytoma showed many mitochondria with a few vesicles in the apical portion of the cytoplasm and rare short and stubby microvilli. The eosinophilic cell variants of clear cell RCC, papillary RCC and chromophobe RCC showed ultrastructural features similar to those of their respective prototypes, except for an increased numbers of mitochondria in the cytoplasm. One sarcomatoid clear cell RCC showed skeletal muscle differentiation. Two types of cytoplasmic inclusions, i.e. hyaline globules and granules similar to those in the Paneth cells (PC-like granules) were identified only in clear cell RCC, which displayed distinctive ultrastructural features. The current EM study demonstrates distinctive ultrastructural features of renal epithelial neoplasms. The findings lend additional support to the current classification of the pertinent tumor types, facilitate the differential diagnoses, and provide insights into the possible histogenesis of renal epithelial neoplasms.     

A method for the isolation of human gastric mucous epithelial cells for primary cell culture: A comparison of biopsy vs surgical tissue

We have developed a method for the isolation and growth of normal human gastric mucous epithelial cells using biopsies or surgically resected tissues as the source of the cells. The attachment and growth of cells were dependent upon: (1) cell planting density, 50,000 cells/cm²; (2) extracellular matrix (fibronectin); and (3) and the use of a porous filter. In all experiments we found better cells attachment and growth of human gastric mucous cells isolated from surgical specimens compared with those gastric mucous cells isolated from gastric biopsies. The initial cell viability (as measured by Trypan-blue) was the same in both populations of gastric mucous epithelial cells isolated from either gastric biopsies or surgical specimens. After 4–5 days in culture one could detect various amounts of mucin in all the cells using either periodic acid Schiff (PAS) staining or a specific anti-mucin antibody. A similar pattern of much straining was also found in primary cultures of guinea pig gastric mucous epithelial cells. Immunohistochemical staining for chief cells (anti-pepsinogen) or parietal cells (anti-H⁺/K⁺ ATPasc) in the gastric mucous cuboidal-like epithelial cells with tight junctions, desmosomes,short microvilli, a filamentous terminal web, mucous granules, and basal lamina-like structure. We could not detect the presence of fibroblasts during the 7–9 days that the primary cells were in culture. This cell culture method will prove useful in the isolation of normal human gastric mucous epithelial cells for in vitro studies of gastric mucosal injury and repair.     

Scanning electron microscopic observation of apical sites of open-type paraneurons in the stomach, intestine and urethra.

The apical region of open-type paraneurons in tubular organs functions as a receptor site for chemical information in the lumen. Electron microscopic studies have demonstrated a tuft of microvilli on the luminal surface of cells, but failed to visualize it three-dimensionally. The present scanning electron microscope (SEM) observation succeeded in viewing, from the luminal side, open-type paraneurons distributed in epithelia of the stomach, intestine, and urethra. The pyloric antrum of avian species and the duodenum of human fetuses, the latter forming an endocrine cell colony at every villus tip, were chosen for SEM observation in order to eliminate visual obstruction by adjacent epithelial cells with developed microvilli. The luminal surface of gut endocrine cells was consistently covered with a tuft of 80-200 microvilli. Pyloric paraneurons possessed thick and stiff microvilli as compared with those of exocrine cells. The microvilli on intestinal paraneurons were more irregular in length and more loosely grouped than those composing the striated border of enterocytes. Urethral paraneurons containing serotonin were surrounded by three or four polygonal epithelial cells. Their narrow apical surface was provided with 30-100 microvilli which varied in length from cell to cell, and which were conspicuously projected above the luminal surface of the urethra. The microvillous crown of the gut and urethral paraneurons was so prominent and constant a structure on the apical surface as to allow easy identification of open-type paraneurons under the SEM.     

Papillary mesothelioma of the tunica vaginalis propria testis

Summary Ultrastructural features of a papillary mesothelioma arising in a hydrocele-sack are reported. The tumour cells presented numerous microvilli, desmosomes, basement membranes and abundant bundles of microfilaments, which all are hallmarks of mesotheliomas. The predominant cell type was the clear epithelial cell, but transitional cells and degenerative forms (foamy cells) were also found. The morphology and differential diagnosis of mesothelial tumours arising in the tunica vaginalis propria testis are discussed.     

幽门螺杆菌细胞微生物学模型的研究

目的 建立幽门螺杆菌(Helicobacter pylori,Hp)细胞微生物学研究模型。方法 选择6至8月龄胎儿胃粘膜组织进行原代细胞培养,运用扫描和透射电镜研究了螺杆状和圆球形Hp与人胃粘膜上皮细胞相互作用关系。结果 螺杆状Hp很快与人胃粘膜上皮细胞微绒毛粘附,Hp粘附细胞处形成一个致密纤维样肌动蛋白垫,上皮细胞膜杯状内陷包绕Hp,紧密粘附于宿主细胞,Hp粘附下方细胞内微丝、微管和肌动蛋白呈局灶性聚集。圆球形Hp可出现类似生物学效应,提示两种形态的Hp皆可作用于人胃粘膜上皮细胞。此外,螺杆状Hp还可与宿主细胞膜融合,被细胞内在化,细胞内出现空泡效应。上述病理性改变与Hp感染的胃粘膜活性组织标本的检查结果基本一致。结论 原代胃粘膜上皮细胞与Hp相互作用近似于Hp体内致病的微环境,是Hp细胞微生物学研究的良好模型。     

Malignant rhabdoid tumor of the prostatic region

Summary We describe a malignant rhabdoid tumour of the prostatic region in a 14-year old boy. The tumour showed positive immunoreactivity for epidermal prekeratin, monoclonal cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and monoclonal vimentin but was negative for myoglobin, alfa-fetoprotein and lysozyme. Electron microscopy revealed pleomorphic cells with collections of paranuclear intermediate filaments, sheaves of tonofilaments and abundant microvilli in some tumour cells. Epithelial derivation was also suggested by occasional intracytoplasmic lumina and rare cell junctions.