Aspiration cytology of neuroblastoma: light microscopy with transmission and scanning electron microscopic correlations

Fine-needle aspiration biopsies from three patients with neuroblastoma were studied by light microscopy, and the morphologic findings were correlated with those from transmission and scanning electron microscopy. Light microscopic examination of the aspiration smears from all three cases revealed small and large round cells with variable numbers of intertwining cytoplasmic processes. Transmission electron microscopy confirmed the light microscopic finding of cytoplasmic processes; in addition, it revealed the presence of other diagnostic morphologic features, including neurosecretory granules, microtubules, and synaptic cell junctions. Scanning electron microscopy demonstrated that the tumors were composed of a mixture of undifferentiated round cells and more differentiated cells with long cytoplasmic processes. The morphologic spectrum of these processes and their interrelationships with one another and with other cells could be studied in detail. These findings indicate that scanning electron microscopy may be used effectively in the morphologic evaluation and pathologic diagnosis of neuroblastoma.     

Scanning electron microscopic study of the human auditory ossicles

The human mallei, incudes and stapedes from 34 cadavers were examined using scanning electron microscope (SEM) to compare the bone surface type among different regions of auditory ossicles for males and females. On the malleus of both males and females, almost all of the surfaces showed a smooth fibrous appearance, characteristic of resting surface. Limited bone-forming or resorbing surfaces were identified on the malleus. As compared with the malleus, the percentage area of the resorbing surface and the vascular canal openings were higher on the incus and stapes, especially on the long process (Crus longum) of the incus and the neck of the stapes for both males and females. The percentage area occupied by the resorbing surface of the long process of the incus and the neck of the stapes correlated with that of the vascular canal openings. We consider that the malleus maintained the stable condition, while the long process of the incus and the neck of the stapes demonstrated marked bone resorption. We suppose that the bone erosion may be related to the vascularization in these regions. Though the percentage area of the resorbing surface and the vascular canal openings had the tendency to be high in females, we did not find any significant differences between the males and females. There was no significant correlation between the age and the area of resorbing surface or vascular canal openings.     

Scanning electron microscopic studies of reticular framework in the rat mesenteric lymph node

Background: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver-impregnated specimens. The aim of the present study is to understand three-dimensionally the ultrastructure and organization of the reticular framework better than before. Methods: The mesenteric lymph nodes of the rat were prepared either an alkali-water maceration method or a conventional method and were observed in a scanning electron microscope (SEM). Results: The SEM study of alkali-water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts. Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley-Liss, Inc.     

Features of the peritoneal covering of the lesser pelvis with special reference to stomata regions

Occasional reports describe various aspects of the fine morphology of the pelvic peritoneum, but its complete organ characteristics remain undefined. The peritoneal covering of the urinary bladder, rectum, uterus, uterine tube, ovary, broad ligament (BL) and testis in Wistar rats was examined by means of transmission and scanning electron microscopy (TEM, SEM). Unusually complicated relief and stomata between the cubic mesothelial cells characterized the surface of the BL. Deep, parallel furrows separated the wide longitudinal folds over the entire length of the uterine tube. The uterus and the ovary formed less numerous, shallow or extremely deep crypt-like invaginations, as well as serous villus-like or papilla-like evaginations. The flat cells were the predominant cell type over the BL, while the cubic mesothelium was the basic covering of the organs. Most of the cubic cells were located in the invagination of the submesothelial layer (SML). Such cells formed an almost smooth surface over the urinary bladder or formed larger areas of the rectum and the testis surfaces. Numerous microvilli, ciliae, round evaginations and complex lamellar bodies characterized their apical plasmalemma. In conclusion, the mesothelial heterogeneity is a stable feature of the lesser pelvis peritoneum, confirmed by TEM and SEM. The cubic mesothelium characterizes the organ peritoneum, while the BL plays the role of the parietal sheet, involving lymphatic units in the SML. The different types of contacts between the mesothelio-endothelial cells, large lymphatic vessels and occasional stomata are the usual components of the lymphatic units in norm, visible by TEM. Images of stomata, seen by SEM, demonstrate oval-shaped deep channel-like gaps surrounded by cubic mesothelium. The last data extend the evidence on stomata regions, which resemble the diaphragmatic ones. Clusters of cells (macrophages, mastocytes and Lymphocytes), small vessels (blood or lymphatic) and nerve fibers (unmyelinated and rare myelinated) form highly specialized complexes in the SML of the ovary, the uterus and the testis.     

Scanning electron microscopic studies of ileal epithelial cells in suckling rats

Summary The ileal epithelial cells containing the tubulo-vacuolar systems and supranuclear vacuoles in suckling rats were investigated with scanning electron microscopy, using specimens treated with osmium-thiocarbohydrazide-osmium staining methods, and critical point drying and cracking.The cracked surface of the apical cytoplasm is seen as irregular and small hollows and pores of the anastomosing and branching tubulo-vacuolar system. The cracked surface of the supranuclear vacuoles shows the ellipsoidal structures. Numerous pores of various size and irregular shape are present on the apical inner surface of the supranuclear vacuole. These pores are clearly the openings from the tubulo-vacuolar system to the supranuclear vacuole. Some small pores are visible on the inner lateral surface of the supranuclear vacuole, especially near the nucleus. They are probably the pathways of the absorbed materials from the supranuclear vacuole into the lateral cytoplasm. Usually, the inclusions of the supranuclear vacuole reveal the globes or coarse and sponge-like networks.     

Scanning electron microscopic investigations of the human umbilical artery intima

Summary Umbilical cord arteries were investigated using a scanning electron microscope using different methods of preparation: Perfusion of one artery under pressure from a 100 cm water column caused artefacts and the preparatory work took at least 10 min after delivery. To shorten this time fully patent umbilical cords were double clamped and fixed immediately after birth. However, the removal of blood after fixation caused the endothelial layer to be lost. Therefore umbilical cords were double clamped, snap frozen and stored in liquid nitrogen until preparation. The endothelial lining of the fully patent umbilical artery at birth is composed of longitudinally arranged, spindleshaped cells, connected by cellular junctions. The basement membrane contains numerous gaps. Because of these gaps postnatal vasoconstriction causes herniation of the subendothelial myofibroblasts forming subendothelial vacuoles. The vacuoles produce displacement of the endothelial cell cytoplasm towards the vascular lumina resulting in protuberances and blebs on the endothelial cells. Rupture of vacuoles leads to crater-like injuries.Beneath the basement membrane a thin layer of myofibroblasts is arranged longitudinally. Oblique or transversely ordered bundles of myofibroblasts are interposed at wide and irregular intervals. These transverse bundles are able to trigger localized contraction rings called folds of Hoboken, the initial stage of postnatal arterial closure.     

Scanning electron microscopic observations of the basement membranes with dithiothreitol separation

Scanning electron microscopic (SEM) studies of the interstitial surface of the lamina densa can be performed with dithiothreitol separation, which is the only method of exposing this surface. SEM observation revealed the three-dimensional structures of the meshwork in the lamina densa and anchoring fibrils in dithiothreitol-separated specimens. Detection of the components of the basement membrane can be performed by immunoscanning electron microscopy on this exposed surface by comparing the backscattered and the secondary electron images. SEM observation also revealed the fine structure of the lamina fibroreticularis using separated dermis or the lamina propria mucosae.     

Ultra-high-resolution scanning electron microscopic studies on the membrane system of the parietal cells of the rat in the resting state and shortly after stimulation

The three-dimensional organization of the membrane system of the rat parietal cells in the resting state and during early stimulation with tetragastrin (gastrin) was determined by ultra-high-resolution scanning electron microscopy. Specimens were prepared by cytoplasmic matrix removal using the aldehyde-osmium-DMSO-osmium procedure. The intracellular canaliculus was lined with numerous microvilli. Viewed from the cytoplasmic side, the intracellular canaliculi appeared as an arborized system of cactus-like structures with numerous round holes about 100 nm in diameter corresponding to the basal openings of the microvilli. The intracellular canaliculi were more developed after gastrin stimulation than in the resting state. In resting cells, most of the tubulovesicles were isolated, 100–200 nm in diameter, spherical or tubular in shape, and had a smooth surface. After gastrin stimulation, these structures were interconnected by slender tubules of about 30 nm in diameter forming together tubulovesicular network. Occasionally, swollen and shrunken profiles were observed. The tubulovesicular network was connected with the intracellular canaliculus only at a few sites by the slender connecting tubules. Fusion of the tubulovesicular network with the intracellular canaliculus is observed at such sites. In the fasted rat, the microvilli were slender and their interior was packed with some kind of ill-defined material, probably microfilaments. However, after gastrin stimulation, the microvilli were swollen and their interior was almost empty. These morphological changes seem to indicate the accumulation of fluid in the microvilli after gastrin stimulation, with subsequent swelling. © 1993 Wiley-Liss Inc.     

Surface and branching of placental villi in early abortion: relationship to karyotype Scanning electron microscopic study

Summary The placental villi of 61 early abortions with known karyotype and 7 legally induced abortions were investigated by scanning electron microscopy and documented in standardised enlargements. Five groups were established from the findings: uniformly branched villi with a velvety surface (group A) were found in 4 of the 7 induced abortions, abundant syncytial sprouts (group B) in 4 of the 6 cases with monosomy X; all 5 cases of triploidy were classified in the group bulbous or spherical villi (group C); 13 out of 25 cases of trisomy were found to have little branching and a surface densely covered with microvilli (group D), while 14 out of the 25 cases of euploidy belonged in the group with slender villi and surface with focal areas of denudation (group E). Forty of the 68 cases were properly assignable to the correct groups (58.8%). The non-uniformity of the villous morphology in the case of induced abortions shows that there is no uniform development of the (early) placenta. The variable morphology seen in abortions with euploidy reflects the various mechanisms of abortion applicable to this group.     

Comparative studies of the same adenocarcinoma cells,macrophages, and mesothelial cells by light microscopy,scanning electron microscopy,and transmission electron microscopy

The identification of cells in body cavities of cancer patients is sometimes difficult to make. In order to make a definite cytological diagnosis, we observed the same cells by using light microscopy (LM)-scanning electron microscopy (SEM)-transmission electron microscopy (TEM). In this study we first stained cells by the Papanicolaou method after fixation in 1% glutaraldehyde for LM, and then attempted to observe them successively by SEM-TEM after fixation in 1% paraformaldehyde and 1.25% O^s0⁴. Our method and procedures in examining successively one and the same cells in body cavity fluids by using LM, SEM, and TEM ensured accurate discrimination among adenocarcinoma cells, mesothelial cells, and macrophages. The results of this study suggest that LM-SEM-TEM may be of diagnostic value in distinguishing among mesothelial cells, macrophages, and adenocarcinoma cells. This method also succeeded in disclosing differences between the ultrastructure of the cell surfaces, and those of the cytoplasm, and of the nuclei It is desirable that LM-SEM-TEM observation can be introduced into various aspects in order to obtain an improvement in the diagnosis by cytologic examination, the judgment of therapeutical effects, drug selection, and prognostic presumption. Diagn Cytopathol 1994; 11:333–342. © 1994 Wiley-Liss, Inc.     

Scanning electron microscopic evidence for neural differentiation in Ewing's sarcoma cell lines

Summary A number of recent studies have suggested a relationship between Ewing's sarcoma (ES) and other small round cell tumours of childhood such as peripheral neuroepithelioma (PN). We report scanning electron microscopic studies on the character of induced neural differentiation in ES, neuroblastoma, PN, osteosarcoma and colon carcinoma. We found evidence of neural differentiation in both neural lines and in one of two Ewing's lines before treatment. After differentiation, both Ewing's and neural lines developed neuritic processes with varicosities and little arborization, except for the initially undifferentiated Ewing's line (A4573) which displayed extensive lateral sprouting from neuritic processes after differentiation. Neither treated nor untreated osteosarcoma or colon carcinoma displayed any evidence of neural differentiation. Further, neuroblastoma cells are easily distinguished from ES and PN by virtue of their single, unbranched neuntes and lack of lateral sprouting or filopodia. These results provide further evidence for the neural character and close relationship between ES and PN.Supported by U.S.-Spain Joint Committee for Scientific and Technological Cooperation Grant No. CCA-8309/058     

Intrahypothalamic connections: An electron microscopic study in the rat

Summary Terminal degeneration within the hypothalamus was studied by electron microscopy 1 or 2 days (1) after carefully placed microlesions in the arcuate, anterior periventricular, ventromedial, premammillary and posterior hypothalamic nuclei and (2) after microlesions placed in the hypothalamus deafferented 3 weeks earlier.In the median eminence terminal degeneration was found after each of these lesions. Projections from the ventromedial nucleus reach the arcuate, suprachiasmatic, and anterior periventricular nuclei.Projections from the arcuate nucleus terminate in the medial preoptic, anterior periventricular, and ventromedial nuclei.After lesioning the premammillary nuclei degeneration was found in the supraoptic, arcuate, anterior hypothalamic and ventromedial nuclei.     

Three-dimensional cytoarchitecture of rat pulmonary venous walls: a light and scanning electron microscopic study

 The three-dimensional architecture of the rat pulmonary veins was studied by light microscopy (LM) and scanning electron microscopy (SEM). For LM, the left lungs were fixed with formalin, sectioned and immunostained with an anti-α-smooth muscle actin (α-SMA) antibody in addition to conventional staining. For SEM, the specimens were fixed with glutaraldehyde and immersed in 30% KOH solution for 8 min followed by treatment of collagenase solution for more than 5 h. By LM, the smooth muscle cells stained with anti-α-SMA showed discontinuous, periodical thickenings of circular bundles in the wall of the venules, but they became thin and continuous in the larger vessels (or veins) that had a cardiac muscle layer on the outside. Under SEM, the smooth muscle cells formed circular-oriented bundles at constant intervals along the venules less than 100 μm in diameter. These bundles had circumferential constrictions in the lumen. The cardiac muscle cells, which appeared in large pulmonary veins of more than 100 μm, ran in a circular or oblique direction and completely surrounded the vessel wall outside of the thin continuous layer of smooth muscle cells. The muscle arrangements were considered to play a significant role in the return blood flow in rat pulmonary veins. Accepted: 15 June 1998     

A scanning electron microscopic study of the morphological changes in rat small intestinal mucosa treated by intracolonic indomethacin

Rectal administration of indomethacin induces longitudinal ulcers in the rat small intestine. The current study investigated a sequence of progressive villus injury in this enteropathy, especially by the use of scanning electron microscopy. The initial change was the distortion of several villi on the mesenteric side in the mid-small intestine identified at 0.5 h, even though there was no obvious change under light microscope or dissecting microscope at this time. During the subsequent 2h, distortion of the villi was accompanied by several epithelial defects, and epithelial detachment occurred on the villi tips. Extension of epithelial defects and exposure of the villus core progressed during subsequent periods. The injured villi were confluent with each other on the mesenteric side throughout the 12h after dosing. These findings suggest that the initial mucosal injury induced by the rectal route of administration was not extensive; rather, several villi were focally damaged on the mesenteric side in the mid-small intestine, eventually resulting in a longitudinal ulcer. Although the overall progression after indomethacin administration by the rectal route was similar to that occurrmg after subcutaneous administration, villus change seems to occur much earlier after rectal dosage.This study was presented in part at the 28th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Osaka, October 17–19, 1996.     

Scanning electron microscopy of the decidual stalk and decidua basalis in the mouse

Summary Placentas either in situ or mechanically separated from their uterine beds were surveyed by scanning electron microscopy to determine the changing relationship of the placenta to its uterine bed with special reference to alteration in the decidua basalis accompanying parturition.At 13 days gestation the placenta is connected to the uterus by a short, broad decidual stalk which becomes longer and more constricted by term. The stalk is covered by a layer of squamous epithelium. Mechanical separation of the placenta and uterus in early gestation reveals that the entire decidua basalis of the decidual stalk is composed of large coarse fibers. As gestation progresses, a relatively smooth acellular capsule forms around the base of the placenta. However, the center of the decidua basalis, the core of the stalk, continues to be composed of large coarse fibers throughout gestation and appears to be the only region penetrated by maternal vessels.     

Scanning electron microscopic studies on coronary microvascular architecture in diabetic human hearts by corrosion cast

Microvascular architecture of 13 diabetic human hearts and 5 nondiabetic control subjects were studied by scanning electron microscopy of corrosion casts. The following results were obtained in the diabetic and nondiabetic hearts. (1) Arterial branches running with remarkable tortuosity were observed in 10 of 13 diabetic hearts, and showed an acute angle, a hairpin turn, a wavelike form, a spiral configuration, a twist, or complex tortuosity. (2) Microaneurysms were found in 11 of 13 diabetic hearts and were observed as spherical, oval, or fusiform. (3) Capillary microaneurysms were found in all diabetic hearts, and observed as saccular form or fusiform. (4) Veins running with remarkable tortuosity or dilations and stenosis were observed in 7 of 13 diabetic hearts. (5) Arterial branches running with remarkable tortuosity were observed in 3 of 5 nondiabetic hearts. (6) Microaneurysms and capillary microaneurysms were not found in nondiabetic hearts. (7) Veins running with remarkable tortuosity were observed in 1 of 5 nondiabetic hearts.     

Scanning electron microscopic study of the changes of the luminal surface of rat thyroid epithelial cells following exposure to cold for 6 to 48 hours (author''s transl)

Zusammenfassung Rasterelektronenmikroskopische Untersuchungen von Schilddrüsenfollikelzellen von Ratten, die 6 bis 48 Stunden einer Temperatur von +4° ausgesetzt gewesen waren, haben gezeigt, dass, im Vergleich mit denen von bei 22° gehaltenen Kontrolltieren, die Zahl der apikalen Mikrovilli zugenommen hat. Diese Ultrastrukturunterschiede — die 48 Studen nach Versuchsbeginn statistisch signifikant sind — stehen in Beziehung mit der durch die Kälteeinwirkung bedingten Aktivitätssteigerung der Schilddrüse.

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Summary Scanning electron microscopic observations of thyroid follicle cells of rats exposed to 4° C for 6 to 48 hours were found to show an increased number of apical microvilli in comparison to those of controls kept at 22° C. These ultrastructural differences — which were statistically significant 48 hours after start of the experiments — are related to stimulation of thyroid gland activity by exposure to cold.

Mit technischer Mitarbeit von Frl. Christa Thommen und Herrn P.-A. Milliquet.