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At least 883 records · Page 49Linked to original sources
PubMed1985

Electron microscopy in selection of patients with small cell carcinoma of the lung for medical versus surgical therapy.

Fifty-one cases of small cell carcinoma of the lung were studied by electron microscopy in order to determine if ultrastructural subsets could be found and if these subsets predicted clinical behavior. All of these cases were considered bona fide small cell carcinoma of the lung by light microscopy. Tumors with ultrastructural features of epithelial differentiation were defined by the presence of well-formed, classic desmosomes joining adjacent cells and by additional features of squamous or glandular differentiation. Thirty-one tumors (60%) were considered "typical oat cell" by electron microscopy and 20 (40%) showed features of epithelial differentiation. Fifteen (75%) tumors with epithelial features were considered operable and nine (45%) were resected with curative intent. In contrast, 26 (84%) tumors considered typical oat cell by electron microscopy presented with extensive metastatic disease. The cancer-free 5-year actuarial survival rate of patients whose tumors showed features of epithelial differentiation was 25%. The actuarial survival rate of nine patients who underwent resection of tumors with epithelial features was 38% at 5 years. Only one patient whose tumor was considered typical of oat cell carcinoma by electron microscopy survived 5 years. Our current recommendation is to remove all clinically resectable pulmonary neoplasms with the expectation that these localized small cell tumors are likely to show epithelial features by electron microscopic analysis.

Carcinoma, Small Cell↗
PubMed1988

[Pili annulati. A scanning electron microscopy study].

A case of ringed hair studied by light and electron microscopy is reported. The patient, a 20-year old girl, had been presenting with the hair abnormality since birth. At naked eye examination the hairs were dry, 6 to 7 cm long, and they showed dull and shining areas giving the scalp hair a scintillating appearance (fig. 1). Several samples of hair were taken and examined by light microscopy under white and polarized light. Hair shafts and cryo-fractured surfaces were examined by scanning electron microscopy. RESULTS. 1. Light microscopy. Lesions were found in every hair examined. There were abnormal, opaque and fusiform areas alternating with normal areas all along the hair shaft (fig. 2). The abnormal areas resulted from intracortical air-filled cavities. Fractures similar to those of trichorrhexis nodosa were found in the opaque areas of the distal parts of the hairs. 2. Scanning electron microscopy. A. Hair shaft surface. The abnormal areas showed a longitudinal, "curtain-like" folding of the cuticular cells which had punctiform depressions on their surface and worn free edges (fig. 4, 5, 6); trichorrhexis-type fractures were seen in the distal parts of the hair shafts (fig. 7, 8). Normal areas regularly presented with longitudinal, superficial, short and non-systematized depressions (fig. 9); the cuticular cells were worn, and there were places where the denuded cortex showed dissociated cortical fibres (fig. 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Scanning electron microscopy as a diagnostic procedure in giant cell arteritis.

Forty-five consecutive patients (32 women and 13 men) underwent biopsy of the temporal artery because of suspected giant cell arteritis. Their ages ranged from 38 to 84 years, mean 68.1 years. Five patients (11.1%) four of them women, were found to be affected by the disease. Their ages ranged from 54 to 80 years, mean 69 years. Clinical and laboratory findings included elevated erythrocyte sedimentation rate, prolonged fever, continuous headache, sudden onset of unilateral blindness, intermittent mandibular claudication, severe anemia and myalgia. None of these, whether present in isolation or in various combinations, were of significant diagnostic value. All biopsies were examined both by light microscopy and by scanning electron microscopy. The former examination took about 5-7 days to complete, and the latter about 3 hours. Light microscopy studies showed that 46.6% of the arterial biopsies were normal, 42.3% were arteriosclerotic and 11.1% (5 specimens) were characteristic of giant cell arteritis. Scanning electron microscopy revealed that the biopsies obtained from all five patients found to have temporal arteritis displayed the "occlusive" pattern: the three-laminar appearance of the artery was markedly distorted or lost, the internal elastic lamina was barely detectable, and the densely hypertrophied media and intima filled the arterial lumen, virtually obliterating it. We conclude that scanning electron microscopy is a quick and accurate procedure for diagnosis of temporal arteritis and that positive findings may be taken as an indication for immediate steroid treatment.

Adult↗
PubMed1975

Localization of acetylcholinesterase in the rabbit cornea by light and electron microscopy.

Acetylcholinesterase (AChE) has been localized in the rabbit cornea by light and electron microscopy histochemical techniques. In the stroma, the enzyme is concentrated in nerves. In the epithelium, the enzyme is concentrated in intercellular spaces devoid of nerves. The morphologic appearance of the enzyme staining by light and electron microscopy in the epithelium is similar; consequently, the staining demonstrated with light microscopy examination does not always represent epithelial nerves. A significant portion of corneal acetylcholinesterase therefore appears unrelated to nerves. Considerably smaller deposits of enzyme reaction product were present in cells in every layer of the cornea, using electron microscopy histochemistry; they were not identified by light microscopy.

Acetylcholinesterase↗
PubMed1977

Electron microscopy in the diagnosis of giardiasis.

Biopsy specimens of intestinal mucosa from two patients with malabsorption syndrome were examined with routine light and electron microscopy. Both showed intact intestinal mucosa, but by electron microscopy, the presence of Giardia lamblia in the intervillar spaces was identified. Electron microscopy is useful for the identification of this parasite, since the stool examinations in up to 50% may be negative. The parasites appear in light microscopy as cellular debris and can be easily overlooked, while by electron microscopy the typical morphologic features of the parasite are diagnostic.

Giardia↗
PubMed1982

Histogenetic classification of lung carcinomas. small cell carcinomas studied by light and electron microscopy.

Forty-six small cell carcinomas of the lung identified by light microscopy were also studied by electron microscopy in an attempt to subclassify them histogenetically. Thirty were subclassifiable into neuroendocrine secretory, mucus secretory, or epidermoid categories on the basis of their differentiated structural features; 16 were too poorly differentiated to assign to any specific cell type and were designated null. In addition to histogenetic separation, electron microscopy revealed a spectrum of average cell differentiation within each subclass except null. The widest spectrum occurred in the most frequent subclass, the neuroendocrine group. This study clearly demonstrated that the light microscopic diagnosis of small cell carcinoma does not identify a morphologically homogeneous process. Whether histogenetic separation and/or some assessment of the relative degree of differentiation have any consistent clinical value remains to be shown; however, combined light and electron microscopy should improve the precision of the initial diagnosis over that of light microscopy alone.

Carcinoid Tumor↗
PubMed1980

[Epithelial invasion of the anterior chamber : exploration by scanning electron microscopy (author's transl)].

Transfixing keratoplasty was performed in a patient seven years after a lens extraction, following the appearance of corneal edema with hypertony and proliferation of a retrocorneal veil. Scanning electron microscopy examination of the posterior surface of the removed graft demonstrated the presence of a vast cellular veil formed of epithelial cells. The principal characteristics of these cells were their polygonal shape, slightly raised edges, and the presence of numerous surface microvilli. Because of the particular characteristics of this epithelium, scanning electron microscopy can be used to observe mitoses in the deep layer as well as for differentiation of the superficial layers. The epithelial cell appears to be identical, as far as its evolution is concerned, both in the aqueous humor and when in contact with the lacrymal film. When compared with other modern investigational techniques, the scanning electron microscope appears to be an effective method for studying epithelial invasion of the anterior chamber. In fact, optical microscopy is of little value in such cases, and transmitted light electron microscopy too heavy a technique for the results expected. Scanning electron microscopy enables precise definition of epithelial cells and can confirm their corneal or conjunctival origin.

Anterior Chamber↗
PubMed1981

Age related changes and osteochondrosis in swine articular and epiphyseal cartilage: light ane electron microscopy.

Age related changes and osteochondrosis in swine were studied using light microscopy and electron microscopy in articular cartilage and light microscopy and epiphyseal cartilage of swine from three days to 30 weeks of age. Thickness, cellularity and vascularity of both the epiphyseal and articular cartilage, decreased as the swine aged. Osteochondrotic changes included formation of "plugs" of cartilage indicating localized failure of ossification and separation and space formation in epiphyseal cartilage. Eosinophilic streaks and space formation in epiphyseal cartilage was observed in relation to epiphyseal separation. Electron microscopy showed a continuous fibrillar layer on the surface of the cartilage corresponding to the lamina splendens of light microscopy. This layer increased in the thickness and showed accumulation of amorphous material between the fibrils with aging. In the matrix, the orientation and distribution of the collagen fibers changed with growth and thicker fibers with clear sub banding were more common in older age groups. Also, necrotic cells, glycogen containing bodies and cellular debris were noticed in the matrix of normal cartilage in old animals. Chondrocytes in the younger cartilage showed accumulation of organelles responsible for protein synthesis; while Golgi bodies, vesicles, lysosomes, well developed foot processes and other inclusions were noticed in older cartilage. Cartilage erosions had a clumped and disrupted lamina splendens on the surface and electron lucent patches in the ground substances of the matrix and chondrocyte cytoplasm.

Aging↗
PubMed1994

Morphologic characteristics of equine endometrium classified as Kenney categories I, II, and III, using light and scanning electron microscopy.

Pathologic changes in the endometrium of mares may be rated according to Kenney's method of classification. Category I endometrium contains healthy tissue with no or few widely scattered pathologic changes. At the opposite end, severe widespread pathologic changes are associated with category III. Uterine biopsy specimens were collected aseptically from 16 mares during the estrous and diestrous stages of the cycle. Pathologic changes were evaluated, using light microscopy, and endometrium was classified as Kenney's category I, II, or III. Endometrial tissue of category I (n = 5 mares in estrus; n = 3 in diestrus); category II (n = 3 in estrus; n = 4 in diestrus), and category III (n = 4 in estrus; n = 4 in diestrus) were processed for scanning electron microscopy (SEM). All specimens were fixed immediately after biopsy because it was found that numerous bleb-like projections were formed when fixation was delayed. Category I endometrium had normal glands, and fibrotic tissue was not observed by light microscopy. Scanning electron microscopy revealed numerous hexagonally shaped cells that were covered with many microvilli. Ciliated cells also were observed, and they contained long healthy cilia. Category II endometrium had 2 to 4 nests surrounded by collagen fibers. Of the 4 specimens, 3 had moderate leukocyte infiltration (59 +/- 14.8 WBC/4 high-power fields [450 x]). Scanning electron microscopy revealed some inflammatory changes with slight swelling of the cell surface. Several cells in category II endometrium lacked microvilli, but they were interdispersed among many healthy hexagonal cells. Many nests were seen in category III tissue, and 2 specimens had severe infiltration of WBC (232,264 cells/4 fields).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A comparison of the usefulness of electron microscopy and immunohistochemistry. One laboratory's experience.

As a quality assurance measure, the usefulness of transmission electron microscopy (EM) and immunohistochemistry (IHC) in our surgical pathology laboratory was compared. The surgical pathology reports from 150 consecutive neoplasms that were examined by both EM and IHC were reviewed. Based on the reported clinical histories, final diagnoses, light microscopy results, and the findings by EM or IHC, the contributions of EM and IHC were classified as "helpful" or "not helpful" for each specimen. Electron microscopy was helpful (92%) more often than was IHC (73%). Electron microscopy was most useful in further classifying poorly differentiated carcinomas, while IHC was particularly useful in classifying poorly differentiated neoplasms. Electron microscopy and IHC were of limited value in identifying the origin of metastatic carcinomas of an uncertain primary. All cases determined to be "not helpful" by either modality were further analyzed to establish a reason for the lack of information provided in each case. This analysis demonstrated a need for improved technical quality and ordering patterns of immunohistochemical stains in our laboratory.

Humans↗
PubMed1996

Examination of cutaneous macroglobulinosis by immunoelectron microscopy.

Cutaneous macroglobulinosis is a rare cutaneous manifestation of Waldenström's disease. Lesions are though to result from accumulation of macroglobulin in the dermis and are therefore called IgM storage papules. Ultrastructural findings in the previously reported cases were contradictory and the nature of the deposits was not established by electron microscopy. The purpose of this study was to analyse such deposits by the use of immunoelectron microscopy. A 60-year-old woman had multiple erythematous papules for 1 year. The histopathological changes consisted of plasmocytic infiltration of the dermis and eosinophilic deposits. The skin changes and other investigations led to a diagnosis of Waldenström's disease. Samples from normal and diseased skin were analysed by electron microscopy and by immunogold labelling with anti-IgM antibodies, after Lowicryl K4M embedding. An extracellular electron dense granular and filamentous material was observed in the mid- and upper dermis, between and within the collagen bundles. No periodicity was noted and no deposits were seen at the dermoepidermal junction. Immunoelectron microscopy showed a positive labelling located only on these deposits, in both normal-appearing skin and in lesions. In this patient, immunoelectron microscopy clearly demonstrated the presence of large amounts of IgM in the dermis, which were found in the lesions of cutaneous macroglobulinosis and in normal skin. These results suggest that the IgM storage papules result from a greater density of deposits rather than a site-specific accumulation.

Female↗
PubMed1999

Morphologic comparisons among equine endometrium categories I, II, and III, using light and transmission electron microscopy.

OBJECTIVE: To evaluate whether the pathologic changes observed by light microscopy in endometrium of categories II and III were reflected by cellular changes and to describe differences in the endometrial cell ultrastructure during estrus and diestrus. ANIMALS: 18 healthy mares. PROCEDURE: Endometrial tissues biopsied during the physiologic breeding season were categorized, using light microscopy, and were studied, using transmission electron microscopy (TEM). RESULTS: Using TEM, glycogen granules were associated with giant mitochondria for all endometrial types during diestrus. Development of rough endoplasmic reticulum (RER) and Golgi apparatus suggested protein synthesis in the endometrial glands during diestrus. TEM did not reveal major ultrastructural differences, between endometrium of categories I and II. This was unlike differences identified by light microscopy. The most extensive pathologic changes were seen in category-III tissue (TEM and light microscopy). Category-III endometria had a large number of light cells with more degenerative structures and fewer organelles, and lacked cilia in the lumen of the glands. This tissue had extensive fibrotic tissue in the lamina propria and many inflammatory cells in most tissue layers. CONCLUSIONS: The severe ultrastructural changes may be one of the many factors decreasing the fertility of mares with category-III, compared with category-1 and -2, endometrium.

Animals↗
PubMed1999

Automated quantification of keratocyte density by using confocal microscopy in vivo.

PURPOSE: To compare keratocyte density determined by using confocal microscopy with keratocyte density determined in the same corneas by histology. METHODS: Digital en face images of central corneas were recorded three times by using confocal microscopy in vivo in six New Zealand White rabbits. Bright objects (keratocyte nuclei) in the images were automatically identified by using a custom algorithm to estimate total and regional stromal keratocyte densities. The corneas were then excised, fixed, and sectioned in a sagittal plane for histology. Keratocyte nuclei were manually counted from digitized images of 50 histologic sections per cornea. Total and regional keratocyte densities were estimated from the histologic sections by using stereologic methods based on nuclei per unit area, mean nuclear diameter, and section thickness. Histologic cell densities were corrected for tissue shrinkage. RESULTS: By confocal microscopy, total keratocyte density was 39,000 +/- 1,200 cells/mm3 (mean +/- SE; n = 6); cell density was 47,100 +/- 1,300 cells/mm3 in the anterior stroma and decreased to 27,900 +/- 2,700 cells/mm3 in the posterior stroma (P = 0.004). Analysis of the three separate confocal images of each cornea produced repeatable total cell densities (mean coefficient of variation = 0.035). By histology, total keratocyte density was 37,800 +/- 1,100 cells/mm3, not significantly different from that estimated by confocal microscopy (P = 0.43); anterior cell density was 48,300 +/- 900 cells/mm3 and decreased to 29,400 +/- 900 cells/mm3 posteriorly (P < 0.001). CONCLUSIONS: Rabbit keratocyte density estimated by automated analysis of confocal microscopy images in vivo is repeatable and agrees with keratocyte density estimated from histologic sections.

Algorithms↗
PubMed1989

Light, scanning, and transmission electron microscopy of a single population of detergent-extracted cardiac myocytes in vitro.

A technique for performing light, scanning, and transverse transmission electron microscopy on cultured cells grown within a single tissue culture flask is described. Permanent light microscopy slides are obtained by removing selected portions of the plastic tissue culture vessel and mounting them on glass slides with an aqueous mounting solution. The images obtained from these slides are superior to viewing through the bottom of the flask with an inverted stage microscope. For scanning electron microscopy, selected areas are also cut from the remainder of the vessel and prepared for viewing. The final portion of the culture container is transferred and attached to a new tissue culture vessel and prepared for transmission electron microscopy using alcohol instead of acetone and propylene oxide during dehydration, infiltration, and embedding.

Animals↗
PubMed2006

Nuclear pore complex structure and plasticity revealed by electron and atomic force microscopy.

To study the ultrastructure of nuclear pore complexes (NPCs), a wide spectrum of different electron microscopy (EM) or atomic force microscopy (AFM) techniques can be employed. The combination of these methods can reveal new insights into the structural and functional organization of this important supramolecular machine through which nucleocytoplasmic transport occurs. Negative staining, quick freezing/freeze-drying/rotary metal shadowing, embedding and thin sectioning, cryoelectron microscopy and tomography, scanning electron microscopy, or combination with immunolabeling techniques are tools for collecting data and information about the three-dimensional structure and architecture of the NPCs. AFM enables investigation of the functional dynamics of native NPCs under physiological conditions.

Animals↗
PubMed1980

Scanning electron microscopy of posterior polymorphous corneal dystrophy.

An 8 1/2-year-old girl had posterior polymorphous dystrophy that required keratoplasty. Similar lesions were found in the patient's mother, thus establishing the genetic trend of the disease. Scanning electron microscopy studies showed areas of endothelial cell degeneration and multiple depressions or pits. These seemed the most advanced and characteristic lesions of posterior polymorphous dystrophy. Transmission electron microscopy studies in areas adjacent to the pits showed an abnormally developed Descemet's membrane covered by two or more layers of elongated endothelial-like cells. Cells over Descemet's membrane seemed to deposit some Descemet's membrane material and both fine and coarse collagen fibrils. Cells had prominent mitochondria, normal endoplasmic reticulum, and desmosomal attachments. Cytoplasmic fibrils and microvilli were usually found in cells lining the anterior chamber. Specular microscopy and scanning electron microscopy recorded the image of only the innermost cells and these appeared as endothelium.

Child↗
PubMed1993

Polarized distribution of the viral glycoproteins of vesicular stomatitis, fowl plague and Semliki Forest viruses in hippocampal neurons in culture: a light and electron microscopy study.

We have shown previously using immunofluorescence microscopy that upon infection of polarized hippocampal cells in culture with vesicular stomatitis virus (VSV) and fowl plague virus (FPV) the VSV glycoprotein is delivered to the plasma membrane of the dendrites and of the cell body whereas the FPV hemagglutinin is transported to the axonal surface (Cell, 62 (1990) 63-72). In this work electron microscopy of infected rat hippocampal neurons showed that VSV progeny budded from the plasma membrane of the dendrites and the cell body. The location of the budding virions corresponded to the distribution of the VSV glycoprotein which was detected over the somatodendritic plasma membrane by immunoelectron microscopy. In contrast, no FPV formation was seen in the infected neurons although the FPV hemagglutinin was localized to the axonal surface by immunoelectron microscopy. In Semliki Forest virus (SFV) infected hippocampal cells we observed that the viral glycoproteins were exclusively present in the dendrites and cell body but not in axons.

Animals↗
PubMed1995

Scanning probe microscopy in microbiology.

Scanning probe microscopy (SPM) is emerging as an important alternative to electron microscopy as a technique for analyzing submicron details on biological surfaces. Microbiological specimens such as viruses, bacteriophages, and ordered bacterial surface layers and membranes have played an important role in the development of scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) in cellular and molecular biology. Early STM studies involving metal-coated bacteriophage T4 polyheads, Methanospirillum hungatei, and Deinococcus radiodurans HPI layer clearly demonstrated that resolution was comparable to TEM on similarly prepared specimens and only limited by metal graininess. However, except for thin films or layers, novel biological information has been difficult to obtain since imaging native surfaces of such biomaterials as proteins or nucleic acids by STM proved to be unreliable. With the development of atomic force microscopes, which allow imaging of similar native structures, SPM applications have widened to include straightforward surface structure analysis, analysis of surface elastic and inelastic properties, bonding force measurements between molecules, and micro-manipulations of such individual molecules as DNA. AFM images have progressed from relatively crude representations of specimen topography to nanometer scale representations of native hydrated surfaces. It appears from the study of microbiological specimens that direct visualization of dynamic molecular events or processes may soon become a reality.

Bacteria↗