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At least 253 records · Page 14Linked to original sources
PubMed1999

Rubber particles from four different species, examined by transmission electron microscopy and electron-paramagnetic-resonance spin labeling, are found to consist of a homogeneous rubber core enclosed by a contiguous, monolayer biomembrane

The physical characteristics of rubber particles from the four rubber (cis-1,4-polyisoprene) producing species Euphorbia lactiflua Phil., Ficus elastica Roxb., Hevea brasiliensis Mull. Arg., and Parthenium argentatum Gray, were investigated using transmission electron microscopy (TEM) and electron-paramagnetic-resonance (EPR) spin labeling spectroscopy. Transmission electron microscopy showed the rubber particles to be composed of a spherical, homogeneous, core of rubber enclosed by a contiguous, electron-dense, single-track surface layer. The biochemical composition of the surface layer and its single-track TEM suggested that a monolayer biomembrane was the surface structure most compatible with the hydrophobic rubber core. The EPR spectra for a series of positional isomers of doxyl stearic acid, used to label the surface layer of the rubber particles, exhibited flexibility gradients and evidence for lipid-protein interactions for all four rubber particle types that is consistent with a biomembrane-like surface. The EPR spectra confirmed that the surface biomembrane is a monolayer. Thus, rubber particles appear similar to oil bodies in their basic architecture. The EPR spectra also provided information on protein location and degree of biomembrane penetration that correlated with the known properties of the rubber-particle-bound proteins. The monolayer biomembrane serves as an interface between the hydrophobic rubber interior and the aqueous cytosol and prevents aggregation of the particles. An unexpected observation for the probes in pure polyisoprene was evidence of an intrinsic flexibility gradient associated with the stearic acid molecule itself.

Journal Article↗
PubMed2001

Confocal laser scanning microscopy and scanning electron microscopy of tissue Ti-implant interfaces.

Microscopic inspection of heterogenous three-dimensional (3D) objects such as oral implants, or implants in general, is conventionally performed either on ground sections of methyl-metacrylate-embedded material, at the cellular level by histologic analysis of the peri-implant tissue by light microscopy (LM), or at the supramolecular level by transmission electron microscopy (TEM). Alternatively, the architecture of the tissue/implant interface is visualized by scanning electron microscopy (SEM). The two approaches exclude each other because of the sample preparation.We elaborate conditions for the non-invasive analysis of tissue/implant interfaces by confocal laser scanning microscopy (CLSM) in buffer, hoping to obtain a 3D view of fluorescently labeled tissue constituents at the tissue implant interface and, through subsequent SEM, of the metal surface. The use of water-immersion objectives, originally developed for high LM under physiological conditions is essential. In an exploratory approach, the tissue/Ti-interfaces of two retrieved dental implants were analyzed. One was a step-cylinder used for orthodontic anchoring and the other was an endosseous step-screw implant retrieved after infection-related loosening prior to load. The adhering tissue fragments were fluorescently triple-labeled for actin, fibronectin, and sm-alpha-actin. Optical sections for fluorescent images and for the laser reflection map were registered concomitantly. This approach allowed the labeled structures to be located on the metal surface. Subsequently, the same implants were prepared for SEM of the tissue/implant interface, and upon removal of the adhering structures, of the underlying metal surface. Thus, specific proteins can be identified and their spatial architecture as well as that of the underlying metal surface can be visualized for one and the same implant. The immediate visualization after fluorescence labeling in buffer by means of water immersion objective lenses proved most critical.

Actins↗
PubMed1985

A new approach for studying semithin sections of human pathological material: intermicroscopic correlation between light microscopy and scanning electron microscopy.

In order to obtain useful and complete information on the study of pathological material, we observed by scanning electron microscopy (SEM) the same semithin sections observed by light microscopy (LM). For this purpose, the specimen must have, at the same time, chromatic and electron dense characteristics. We thus developed different specimen preparation methods, subjecting the semithin sections to specific polychromatic staining with high atomic number (Z) elements, to monochromatic staining followed by routine contrasting with uranyl acetate and lead citrate, and to specific cytochemical and immunocytochemical procedures. The specimens were examined in sequence by LM, by SEM equipped with secondary electron, backscattered electron, transmitted electron detectors and by scanning transmission electron microscopy (S(T)EM).

Actins↗
PubMed2003

Combined use of confocal laser scanning microscopy and transmission electron microscopy for visualisation of identical cells processed by cryotechniques.

Successive visualisation of identical plant cells by light and electron microscopy is reported. For this purpose segments of pea and barley leaves were prepared by high-pressure freezing, freeze-substitution, and low-temperature embedding. The use of Safranin O during low-temperature dehydration allowed, on one hand, staining of all cellular components as investigated by confocal laser scanning microscopy and, on the other hand, excellent ultrastructural and antigenic preservation. A newly constructed specimen holder enabled precise relocation of the target cells for electron microscopic investigations. Transmission electron microscopy and immunohistochemistry revealed that during the whole procedure the ultrastructure of the cells as well as the antigenicity of cell constituents were preserved.

Cryoelectron Microscopy↗
PubMed1985

Flagellate pigmentation from intrapleural bleomycin. A light microscopy and electron microscopy study.

A case is presented of a 65-year-old white man with left pleural mesothelioma treated with a single intrapleural instillation of bleomycin for cavitary sclerosis. One month later the patient developed pigmented flagellate streaks on his arms and chest wall. To our knowledge, this is the first case in the literature showing these typical pigmentary changes in which a single small dose of bleomycin acted as an intrapleural sclerosing agent.

Aged↗
PubMed1980

Molecular and morphological evidence for type B retrovirus (oncornavirus) expression in human mammary carcinoma. An overview using scanning electron microscopy, immunoperoxidase staining, and transmission electron microscopy.

Approximately 45% of human mammary carcinoma cases express an antigen which cross reacts in formalin fixed tissues with antiserum prepared against the purified 52,000 molecular weight structural glycoprotein (gp52) of mouse mammary tumor virus (MMTV). Breast carcinoma immunoperoxidase marking is abolished by antiserum adsorption with MMTV. Adsorption with murine leukemia virus failed to block immunoperoxidase marking. No correlation was seen in the cases analyzed between gp52-like antigen expression and family history of mammary carcinoma, age, or pathological classification. The evidence linking an oncornaviral agent in human mammary carcinoma is reviewed with respect to the structure and biology of a known etiological agent, MMTV, in murine mammary cancer. The potential role of SEM in amplifying the surface area available for analysis in malignant and premalignant human breast epithelia is considered.

Antigens, Neoplasm↗
PubMedDate not supplied

Microcomputer application: an image database system for electron microscopy.

An electron microscopist in a small electron microscopy laboratory that processes 200 cases per year can generate at least 2000 electron micrographs within this time period. These electron micrographs are stored in filing cabinets, which slowly encroach on existing laboratory space. Related image data are often located in separate filing systems. This type of storage system is inefficient for rapid retrieval of sets of electron micrographs for research, teaching, or retrospective review of patient material. An electron microscopy image base, which is implemented on a microcomputer, can provide flexible and simultaneous access to both digitized electron micrographs and their relevant textual data. In addition to the advantage of more efficient retrieval, electronic storage of textual data and digitized electron micrographs also offers the advantage of decreased storage space for this type of data. Implementation of the initial version of the electron microscopy image base demonstrated that future versions must provide improved resolution of the digitized electron micrograph and sufficient electronic mass storage to support such a large image base. Ongoing developments in database technology and mass storage make it worthwhile to pursue additional refinements of the electron microscopy image base.

Database Management Systems↗
PubMed1997

Confocal light microscopy and scanning electron microscopy of the human eye lens.

The potential of confocal light microscopy (CLM) for in vivo observation of pathology in the anterior pole of the eye lenses was evaluated by performing an in vitro study of human lenses comparing this type of microscopy with scanning electron microscopy (SEM). In vitro CLM showed high resolution images of the epithelium which would enable early detection of pathology and easily allows cell counting and estimating cell size. Superficial lens fibres are well visualised and low and high frequency bands as well as vacuolar elements were easily detected. SEM observations fully supported the CLM observations. This study shows that CLM has the potential to become a useful tool for detecting lens changes, after suitable adaptation for clinical use.

Adult↗
PubMed1987

Techniques for combining light microscopy and scanning electron microscopy: a survey of the literature.

A survey of methods combining light microscopy and scanning electron microscopy is presented. A simple correlation is made when two preparations from adjacent parts of one specimen are investigated in two different microscopes. A more sophisticated method is the consecutive investigation of one specimen with two microscopes. A major problem in this method is the relocation of the area of interest. Several authors have presented solutions for this problem. It is preferable when one preparation is investigated in only one instrument, combining the two microscopical (LM and SEM) techniques, thus making relocation redundant.

Microscopy↗
PubMed2002

Deposition of nanoparticles in the arterial vessel by porous balloon catheters: localization by confocal laser scanning microscopy and transmission electron microscopy.

Restenosis remains the major limitation of percutaneous transluminal angioplasty (PTA) and stenting in the treatment of patients with atherosclerotic disease. Catheter-based local delivery of pharmacologic agents offers a potential therapeutic approach to reducing restenosis and minimizing undesirable systemic side effects. However, the intramural retention of liquid agents is low. Therefore, to achieve a sustained and regional release of the therapeutic agent it must be encapsulated in nanoparticle carrier systems. The purpose of this study was to investigate the size dependence of the penetration of nanoparticles after local delivery into the vessel wall of the aorta abdominalis of New Zealand white rabbits. Two milliliters of a 0.025% fluorescence-labeled polystyrene nanoparticle suspension with diameters ranging from 110 to 514 nm were infused at 2 atm and at constant PTA pressure of 8 atm into the aorta abdominalis. After the infused segments were removed, the location of nanoparticles was visualized using confocal laser scanning microscopy and transmission electron microscopy. The study demonstrates a size-dependent nanoparticle penetration into the intact vessel wall. While nanoparticles of about 100 and 200 nm were deposited in the inner regions of the vessel wall, 514-nm nanoparticles accumulated primarily at the luminal surface of the aorta. The observations confirm that size plays a critical role in the distribution of particles in the arterial vessel wall. It is additionally influenced by the formation of pressure-induced infusion channels, as well as by the existence of anatomic barriers, such as plaques, at the luminal surface of the aorta or the connective elastic tissue.

Animals↗
PubMed1989

[Application of polarized microscopy and analytic electron microscopy in pneumoconiotic pathologic examination].

38 cases of pneumoconiotic pathologic slides have been reexamined by polarized microscopy, among this, 3 cases (every 1 case of silicosis, asbestosis, cement dusts pneumoconiosis) have investigated by analytic electron microscopy. Authors presented, crystal silica and asbestos fiber may be showing under polarized light, and often associated with carbon dusts or fibrotic proliferation. So that, polarized microscopy may be as a preliminary detect method for silica and uncoated asbestos fiber from histologic slide, according to its dimension, color, lightness, morphologic feature and position were differential diagnosis from other positive substance under routine pathologic examination, further demonstration must to be reduced to ashes and re-observation under polarized microscopy. Also we selected 3 cases of silicosis, asbestosis, cement dusts pneumoconiosis specimen prepared to ultramicrotomic slides and examined by H-800 electron microscopy, when discovered some particles (such as crystal, non-crystal or fibrotic dusts) in cytoplasm of macrophages or interstitial space then used EDAX estimated. Its elements distribution were conformity with dusts (silica, asbestos, cement dusts).

Anthracosilicosis↗