Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microscopy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,207 records · Page 67Linked to original sources
PubMed1988

Nail changes in alopecia areata: light and electron microscopy.

Fragments of nail keratin removed with tweezers from patients suffering from alopecia areata were examined using light microscopy and electron microscopy. The results obtained from these two techniques show nail changes which are slits, cupuliform dips of the upper edge and parakeratosis, under light microscopy; vacuoles, depletion of keratin fibers, and electron-dense fibrillary deposits, under electron microscopy. These changes predominate in the nail plate with a maximum in the upper part while the subungual keratin is preserved. A serious disorder of the matrix keratinization is probably the source of this preferential localization. To determine whether it is a disorder of the keratin fibers themselves or rather of the interfilamentary matrix and especially of the filaggrin system will require further biochemical and immunological studies.

Alopecia Areata↗
PubMed1989

Quantitative microscopy and artificial intelligence: some philosophical reflections.

The interdisciplinary field of quantitative microscopy (computer-aided microscopy) and artificial image understanding systems is explored, with an emphasis on the philosophical aspects of pathology and artificial intelligence. Three methodological problems of traditional diagnostic pathology are identified: those of validity, variability and organisation. Quantitative microscopy is a potential research strategy for solving these problems. In practice, however, the quantitative microscopy program is handicapped by the difficulty of building artificial image-understanding systems. We discuss the segmentation problem in image understanding, and four general strategies, three cognitivistic and one connectionistic, are reviewed.

Artificial Intelligence↗
PubMed1989

Lupus nephritis--light, electron and immunofluorescent microscopy (a clinicopathological study).

Kidney biopsy specimens from nine patients of systemic lupus erythematosus were studied for the purpose of correlating the findings of light and electron microscopy and immunofluorescent studies with the kidney functions and the presence of proteinuria. Morphologically, three were mesangiocapillary glomerulonephritis, three mesangioproliferative glomerulonephritis and one membranous nephropathy. Subendothelial deposits were observed in eight cases, subepithelial deposits in seven cases and mesangial deposits in eight cases. Four cases with massive subendothelial deposits had massive proteinuria and decrease in renal functions. Most of the patients with mild subendothelial deposits were considered to be useful in assessing the prognosis and severity of lupus nephropathy, in addition to the morphologic types of lesions, as mesangial pattern had shown insignificant proteinuria. Study of semithin sections by light microscopy could demonstrate the deposits which were observed on electron microscopy and immuno-fluorescent microscopy.

Adult↗
PubMed1989

[Laser scan microscopy: a new imaging procedure in quality assessment of artificial lenses].

Laser-scan microscopy permits the evaluation of surfaces and deeper layers of an object by computer-assisted scanning with a laser beam. The reflected helium-neon or argon laser light is transmitted to a photodetector and after signal processing, to a frame store and a TV monitor. Imaging is realized by synchronous scanning and modulation of light intensity. Laser-scan microscopy revealed a smooth surface of both PMMA and HEMA lenses, whereas tears were detected in folded silicone implants. The physical and chemical homogeneity inside the three different materials was optimal. Compared to scanning electron microscopy, the quality of imaging is not as good with laser-scan microscopy. Nevertheless, one decisive advantage of the latter method is an analysis free of processing and artifacts, which permits a routine control of brand new and folded intraocular lenses.

Humans↗
PubMed1987

The use of electron microscopy and immunohistochemistry in the diagnosis and understanding of lung neoplasms.

This article has presented information concerning the ultrastructural features and, to a lesser degree, the immunohistochemical characteristics of lung neoplasms. Electron microscopy and immunohistochemistry are useful techniques for diagnosing and understanding common and rare lung tumors. Electron microscopy is particularly helpful in accurately diagnosing undifferentiated lung tumors such as large-cell undifferentiated and small-cell undifferentiated carcinomas. Ultrastructural studies of lung tumors have also aided in overall understanding of the histogenesis of these tumors. Electron microscopy and immunohistochemistry are techniques that can be applied to tiny specimens, including those obtained via fine-needle aspiration biopsy, and to cells obtained from pleural fluid. An intelligent use of electron microscopy and immunohistochemistry aids in the diagnosis and understanding of lung neoplasms.

Adenocarcinoma↗
PubMed1987

[Alkaline phosphatase activity in human gliomas as revealed by light and electron microscopy].

Precise localization of alkaline phosphatase (ALPase) activity in human gliomas was examined by light and electron microscopy in association with malignant transformation, paying much attention to changes in blood-brain barrier. Materials used were eight cases of gliomas four of which were astrocytoma grade 2, one astrocytoma grade 3, and three, glioblastoma multiforme, respectively. Specimens were quickly fixed in cacodylate-buffered 2% glutaraldehyde at 4 degrees C for 1 hour and rinsed overnight in the same buffer. Frozen or nonfrozen sections (40 microns thick) were made and incubated at 20 degrees C for 40 min, and processed for light and electron microscopy. For the demonstration of ALPase activity, the lead citrate method (Mayahara et al., 1967) was employed. By light microscopy, ALPase activity appeared to be mainly restricted to the capillary wall. By electron microscopy, reaction product representing ALPase activity was distributed in the plasma membrane of endothelial cells both in astrocytomas and in glioblastoma. In astrocytoma grade 2, activity was primarily localized along the abluminal surface of endothelial cells. In glioblastoma, on the other hand, ALPase activity was positive on the luminal surface of the plasma membrane of endothelial cells. It was much more intense than that along the abluminal surface. Regional differences in enzyme cytochemistry may represent functional heterogeneity in the endothelial cell membrane. In brain tumors, changes in distribution pattern of enzyme activity were visualized in the present study in association with glioma malignancy. This might represent a functional aspect of changes in blood-brain barrier in human glioma tissue during course of its malignant transformation.

Adult↗
PubMed1988

[Ultrasound microscopy of skin sections].

In vivo ultrasound examination has been introduced into dermatology as a non-invasive diagnostic technique. The resolution capacity, however, has been limited so far, and the in vivo ultrasonic features have not been fully understood. Using high frequencies (GHz range) in acoustic microscopy, we have been able to achieve a resolution comparable to that in light microscopy. In a first step, we examined normal human skin sections and compared them to histological specimens. The following study on melanocytic nevi, malignant melanoma, and metastases of melanoma showed that their acoustic images were more pronounced than those of the surrounding tissue. The echo intensity of solid basal cell carcinoma and squamous cell carcinoma resembled that of the epithelium. The structures found in acoustic microscopy can be correlated to those seen in light microscopy.

Biopsy↗
PubMed1985

Combined light and electron microscopy of Golgi-labelled neurons in lamina III of the feline spinal cord.

Golgi-impregnated neurons in lamina III of the cat spinal cord were examined using light microscopy and combined light and electron microscopy. Light microscopy revealed that the neurons formed a variety of dendrite configurations. The majority of neurons arborised in the rostrocaudal plane and were confined to the lamina of origin. However, some arborised dorsoventrally and had dendrites that penetrated lamina II. Electron microscopy of the neurons revealed that they were associated with many different types of bouton, thus suggesting that they received synaptic input from various sources. Some of the boutons were postsynaptic to other axon terminals indicating that they are under presynaptic control. One of the neurons participated in synaptic triads which consisted of two axo-axonically coupled boutons that were presynaptic to the cell.

Animals↗
PubMed1979

Diagnostic applications of scanning electron microscopy and microanalysis in pathology.

Microanalytical technology developed within the last decade provides important information in diagnostic pathology. Scanning electron microscopy, including backscattered electron imaging and energy dispersive X-ray analysis should become at least as valuable as polarized light microscopy, histochemistry and conventional transmission electron microscopy. Other as yet less available techniques such as the ion microprobe and laser Raman microprobe are also valuable. The pathologist should consider the use of microanalytic techniques in any disease process in which endogenous or exogenous materials may be present in the tissues, in the same manner in which one would perform stains for microorganisms. Cases are presented illustrating the tissue preparation and results of scanning electron microscopy and energy dispersive X-ray analysis in diagnosis.

Electron Probe Microanalysis↗
PubMed1977

[Observations by scanning electron microscopy (SEM) on the surface of mesothelial cells of different peritoneal areas of rat (author's transl)].

Observations by Scanning electron microscopy (SEM) showed numerous microvilli on the surface of mesothelial cells of different peritoneal areas. In addition a number of saccular invaginations provided with microvilli or small intercellular clefts have been observed between the cells. These superficial invaginations may correspond to the "stomata" of the light microscopy. Because of the number of microvilli projecting inside the clefts it was not possible to determine whether they open directly on the base of the cells. As the light of the Scanning electron microscopy observations and considering the transmission electron microscopy results on the intercellular boundaries in mesothelial cells it is possible to assume that the actual clefts ("stomata") are continuous and open in the main intercellular channels. Then it is not possible to exclude that these intercellular channels with their labyrinthine and tortuous course may open into the subjacent connective tissue.

Animals↗
PubMed1982

Identification of microglia cell of the rat retina by light and electron microscopy.

Distribution of microglia cells was studied in the normal retina of Wistar rats kept in a specific-pathogen-free condition, using a combined technique of light and electron microscopy with the weak silver carbonate staining method of del Rio-Hortega. Typical microglia cells were found mainly in the inner plexiform layer. By electron microscopy these cells were easily identified by metallic deposition in the cells, and had a small oval nucleus with a prominent chromatin pattern, which was one of the most characteristic features of the cell. Based upon these fine structures, microglia cells were identified in the nonimpregnated, ordinarily prepared retina by electron microscopy. These cells contained lysosomes, lipofuscin granules, Golgi apparatus, and long, narrow cisternae of rough-surfaced endoplasmic reticulum mainly at both sides of the perikaryon. These features were identical with those of microglia cells in the central nervous system. Microglia cells were found to be widely distributed in the inner portion of the retina, most of the cells locating closely to ganglion cells or capillary walls, and occasionally in the inner plexiform layer. The nuclear feature of the cell was also recognizable by light microscopy in 1-micron-thick Epon sections stained with toluidine blue. Serially cut thick sections of the retinal ribbon revealed that microglia cells were widely distributed from the peripapillary to the ora serrata region. From the present study, it is concluded that the microglia cell can be considered a component of the normal retina. This is the first report on the precisely described fine structures of the retinal microglia cells.

Animals↗
PubMed1980

[Scanning electron microscopy of human cultured gliomas (author's transl)].

Tumor tissues of glioblastoma multiforme, astrocytoma and medulloblastoma, maintained up to 21--28 days by gelfoam organ culture technique, were examined by scanning electron microscopy (SEM). Glioblastoma multiform has irregular cell surface and many cytoplasmic folds. Astrocytoma has many fibrils. The fibrils have smooth surface and are coiling. Fibrils of piloid astrocytoma are smooth and cylindrical. The focal thickness of fibrils are associated with so-called Rosenthal fiber. Capillary of astrocytoma has irregular surface and marked tortuosity. Medulloblastoma is composed of non-fibrillated round tumor cells. The tumor cells touch each other with short cell processes. These findings seemed to correspond to the malignancy of original tumor. Comparative observation of medulloblastoma maintained by monolayer cell culture with one maintained by organ culture, using light microscopy and scanning electron microscopy, was done. And medulloblastoma in monolayer culture was proliferated to two types of cells. One is epitheloid cell with taper cell processes, and the other is stellate cell with fine processes. In most organ culture, feature of cells corresponded to those observed in original surgical material by light microscopy.

Astrocytoma↗
PubMed1981

Cell cycle-related morphological changes of feline lymphoid cells as revealed by electron microscopy.

The aim of this study was to correlate morphological changes in cells to known phases of the cell cycle. For this purpose, feline lymphoblastoid cells (FL74) chronically infected with feline leukemia virus were synchronized and examined by scanning and transmission electron microscopy. Scanning electron microscopy revealed that the cell surface underwent distinct changes which were found to be cell cycle specific. Morphological changes shown by transmission electron microscopy were used as ultrastructural markers to confirm the findings made by scanning electron microscopy relating to the various phases of the cell cycle. The results of these experiments suggest that the presence of morphologically mixed populations of cells in many lymphoproliferative disorders, which had been described previously, may be explained by normal cell cycle-dependent variations.

Animals↗
PubMed1983

The past, present, and future of clinical specular microscopy.

Since the introduction of specular microscopy into the field of clinical ophthalmology in 1975, many technological and methodological advances have been made. These have for the most part eliminated the previously discussed objections to the use of specular microscopy as a clinical tool. With the advent of new instrumentation, a number of specular microscopes are not available. The advantages and disadvantages of these clinical specular microscopes, current clinical practice with small-field and wide-field specular microscopy, and description of problems and possible future developments of specular microscopy are discussed.

Cornea↗
PubMed1980

Scanning electron microscopy of brain ventricular surfaces: a bibliography.

This bibliography is designed to facilitate the rapid identification and location of references concerning the application of scanning electron microscopy to investigations of the cerebroventricular system and related cerebrospinal fluid contacting surfaces. Because SEM provides information regarding cell surfaces, it is admirably suited to the examination of the brain ventricular system since the morphology of the CSF interface is of the utmost importance in accomplishing the diverse functions of the ependyma and associated circumventricular organs. The bibliography attests to the fact that scanning electron microscopy has provided a major impetus to the study of the structure and function of the circumventricular organs, choroid plexuses and tanycytic ependyma as well as the distribution and morphology of such supraependymal cellular elements as macrophages, neurons, and neuronal proceses. Furthermore, not only are SEM methodologies being applied to an ever lengthening list of phyla and species, but the diversity of problems amenable to the profitable application of scanning electron microscopy also is rapidly increasing. Investigations to date, for example, include studies of ventricular morphology during development and maturity, health and disease, and prior to as well as following experimental manipulation. While remarkable strides have been made toward a greater understanding of many aspects of cerebroventricula structrure and function, many significant problems clearly await the judicious application of scanning electron microscopy.

Bibliographies as Topic↗
PubMed1981

Scanning electron microscopy of cyclophosphamide-induced hyperplasia of the rat urinary bladder.

Urinary bladder damage caused by cyclophosphamide in male F344 rats was studied by light microscopy, scanning electron microscopy, and autoradiography. Cyclophosphamide was injected intraperitoneally at doses of 50, 75, 100, 150, and 200 mg. per kg. of body weight, and rats were killed at several intervals following treatment. Extensive necrosis of the bladder was followed by regenerative hyperplasia of the epithelium. A dose response was evident in the number and size of lesions induced and the time of regeneration and repair. Scanning electron microscopy disclosed pleomorphic microvilli on the luminal surface of cells during the early phases of hyperplasia. The greatest number of cells with pleomorphic microvilli occurred 2, 5 and 7 to 8 days following injection of 75, 100, and 200 mg. per kg. of cyclophosphamide, respectively. The hyperplastic lesions also had cells with short, uniform microvilli and ropy or leafy microridges on their surfaces. Autoradiographs of the urinary bladders showed marked labeling of epithelial cells in the early phase of hyperplasia. Of the few rats surviving beyond 1 year after a single injection, none had bladder lesions at any of the dose levels. The changes in the epithelium observed by scanning electron microscopy following cyclophosphamide injection were compared to those observed during bladder carcinogenesis.

Animals↗
PubMed1995

Detection of silica particles in lung tissue by polarizing light microscopy.

The detectability of silica particles in ordinary histologic sections by means of polarizing light microscopy has been controversial. Through the application of both correlative light microscopy and scanning electron microscopy to different lung sections, we showed that particles demonstrating peaks for silicon only by energy-dispersive x-ray microanalysis were in fact visible by polarizing light microscopy. These particles included some silica particles less than 1 microns in diameter. We found no correlation between the intensity level of the light source used for polarization and the differential ease of visualizing silica versus silicates; examples of both could be detected at both relatively low and high light intensities. This suggests that geometric parameters may be as important as composition in the ease of detection of silica versus silicates with polarized light.

Electron Probe Microanalysis↗
PubMed1996

Synaptic remodeling revealed by repeated in vivo observations and electron microscopy of identified frog neuromuscular junctions.

This work aimed to examine the mechanism of synaptic remodeling using repeated in vivo observations, followed by electron microscopy, of identified frog neuromuscular junctions (NMJs). Our previous light microscopic studies suggested that extension of synaptic extracellular matrix (ECM) precedes, and may play a role in, nerve terminal (NT) growth during synaptic remodeling. To test this hypothesis, sartorius muscles were double labeled with a fluorescent dye, 4-(4-diethylamino-styryl)-N-methylpyridinium iodide, for NTs and rhodamine-conjugated peanut agglutinin for synaptic ECM. The double-labeled NMJs were observed in vivo with video-enhanced fluorescence microscopy. Two to three months after nerve sprouting was induced by a nerve graft, the same NMJs were restained and reexamined. After the final in vivo observations, the same NMJs were examined with semiserial thin section electron microscopy. Light microscopic observation of NMJs that showed synaptic ECM longer than the NT was confirmed with electron microscopy. At junctional branches where synaptic ECM extended beyond the NT, a Schwann cell process longer than the NT was observed in one example, whereas a Schwann cell with the same length as the NT was seen in other examples. In both cases, junctional folds were absent at the extended ECM region. In contrast, junctional folds were observed at the region vacated by a retracted NT. These results suggest that extension of synaptic ECM and Schwann cell processes may lead, and play a role in, the NT growth during the remodeling of adult synaptic connections.

Animals↗