Ultrastructural mitral valve abnormalities in infective endocarditis

Aim. Using an original method based on backscattered scanning electron microscopy, to study the structural features of the mitral valve leaflets in infective endocarditis.Material and methods. We examined 9 mitral valves extracted during surgical interventions due to structural malfunction in patients with infective endocarditis (IE). The samples were fixed in buffered paraformaldehyde with osmium tetraoxide postfixation. After dehydration by increasing alcohol concentration and acetone, the samples were placed in epoxy resin. After the resin has polymerized, the samples were ground and then polished to the desired depth. To increase the electronic contrast, the samples were treated with a uranyl acetate alcohol solution during dehydration and with Reynolds' lead citrate after polishing the epoxy blocks. The samples were visualized by backscattered scanning electron microscopy at an accelerating 15-kV voltage.Results. Structural leaflet injuries caused by IE were most pronounced in the central part and the base. Necrotic areas were extensive electron-dense formations located in the central leaflet layers, or displaced towards the ventricular surface. The electron-dense material in the necrotic area was poorly structured and contained individual cells and bacteria. Bacteria were also present outside the necrotic area. Necrotic areas were surrounded by a layer of a modified extracellular matrix, usually covered with a fibrin layer. Among the extracellular matrix fibers, the macrophages, smooth myocytes and fibroblasts was noted. The fibrin layer, in addition to these cells, contained a large number of blood vessels and was often covered with endothelium.Conclusion. Infection of the mitral valve leaflets causes a simultaneous inflammatory response and regeneration activation. Without adequate regulatory factors, the processes of inflammation and connective tissue creation lead to structural and functional leaflet failure. Specific causes may be overgrowth of necrotic and inflammatory areas, edema and fiber orientation disorder, as well as leaflet rupture.

Download Full-text

Neutrophil Derived Cathepsin G Induces Potentially Thrombogenic Changes in Human Endothelial Cells: a Scanning Electron Microscopy Study in Static and Dynamic Conditions

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648825 ◽

1994 ◽

Vol 72 (01) ◽

pp. 140-145 ◽

Cited By ~ 13

Author(s):

Valeri Kolpakov ◽

Maria Cristina D'Adamo ◽

Lorena Salvatore ◽

Concetta Amore ◽

Alexander Mironov ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Extracellular Matrix ◽

Endothelial Cells ◽

Thrombus Formation ◽

Cathepsin G ◽

Arterial Segment ◽

Dynamic Conditions ◽

Activated Neutrophils ◽

Scanning Electron

SummaryActivated neutrophils may promote thrombus formation by releasing proteases which may activate platelets, impair the fibrinolytic balance and injure the endothelial monolayer.We have investigated the morphological correlates of damage induced by activated neutrophils on the vascular wall, in particular the vascular injury induced by released cathepsin G in both static and dynamic conditions.Human umbilical vein endothelial cells were studied both in a cell culture system and in a model of perfused umbilical veins. At scanning electron microscopy, progressive alterations of the cell monolayer resulted in cell contraction, disruption of the intercellular contacts, formation of gaps and cell detachment.Contraction was associated with shape change of the endothelial cells, that appeared star-like, while the underlying extracellular matrix, a potentially thrombogenic surface, was exposed. Comparable cellular response was observed in an “in vivo” model of perfused rat arterial segment. Interestingly, cathepsin G was active at lower concentrations in perfused vessels than in culture systems. Restoration of blood flow in the arterial segment previously damaged by cathepsin G caused adhesion and spreading of platelets on the surface of the exposed extracellular matrix. The subsequent deposition of a fibrin network among adherent platelets, could be at least partially ascribed to the inhibition by cathepsin G of the vascular fibrinolytic potential.This study supports the suggestion that the release of cathepsin G by activated neutrophils, f.i. during inflammation, may contribute to thrombus formation by inducing extensive vascular damage.

Download Full-text

Histomorphometric Analysis of Osseointegrated Grade V Titanium Mini Transitional Implants in Edentulous Mandible by Backscattered Scanning Electron Microscopy (BS-SEM)

Metals ◽

10.3390/met11010002 ◽

2020 ◽

Vol 11 (1) ◽

pp. 2

Author(s):

Víctor Beltrán ◽

Benjamín Weber ◽

Ricardo Lillo ◽

María-Cristina Manzanares ◽

Cristina Sanzana ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Bone Tissue ◽

Mechanical Load ◽

Histomorphometric Analysis ◽

Woven Bone ◽

Edentulous Mandible ◽

Calcified Tissues ◽

Backscattered Scanning Electron Microscopy ◽

Scanning Electron

The purpose of this study is to assess the use of grade V titanium mini transitional implants (MTIs) immediately loaded by a temporary overdenture. For this, a histomorphometric analysis of the bone area fraction occupancy (BAFO) was performed by backscattered scanning electron microscopy (BS-SEM). Four female patients were submitted to surgery in which two MTIs were installed and immediately loaded with a temporary acrylic prosthesis. During the same surgery, two regular diameter implants were placed inside the bone and maintained without mechanical load. After 8 months, the MTIs were extracted using a trephine and processed for ultrastructural bone analysis by BS-SEM, and the regular-diameter implants were loaded with an overdenture device. A total of 243 BAFOs of MTIs were analyzed, of which 94 were mainly filled with cortical bone, while 149 were mainly filled with trabecular bone. Bone tissue analysis considering the total BAFOs with calcified tissues showed 72.13% lamellar bone, 26.04% woven bone, and 1.82% chondroid bone without significant differences between the samples. This study revealed that grade V titanium used in immediately loaded MTI was successfully osseointegrated by a mature and vascularized bone tissue as assessed from the BAFO.

Download Full-text

Wood identification of charcoal with 3D-reflected light microscopy

IAWA Journal ◽

10.1163/22941932-bja10033 ◽

2020 ◽

Vol 41 (4) ◽

pp. 478-489 ◽

Cited By ~ 1

Author(s):

Valentina Zemke ◽

Volker Haag ◽

Gerald Koch

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Light Microscopy ◽

Field Emission ◽

Polarized Light ◽

Structural Features ◽

Light Illumination ◽

Reflected Light ◽

Carbonized Wood ◽

Scanning Electron

Abstract The present study focusses on the application of 3D-reflected light microscopy (3D-RLM) for the wood anatomical identification of charcoal specimens produced from domestic and tropical timbers. This special microscopic technique offers a detailed investigation of anatomical features in charcoal directly compared with the quality of field emission scanning electron microscopy (FESEM). The advantages of using the 3D-RLM technology are that fresh fracture planes of charcoal can be directly observed under the microscope without further preparation or surface treatment. Furthermore, the 3D-technique with integrated polarized light illumination creates high-contrast images of uneven and black charcoal surfaces. Important diagnostic structural features such as septate fibres and intercellular canals can be clearly detected and intervessel pits are directly measured. The comparison of the microscopic analyses reveals that 3D-reflected light microscopy (3D-RLM) provides an effective alternative technique to conventional field emission scanning electron microscopy for the identification of carbonized wood.

Download Full-text

Extracellular matrix in ascending aortic aneurysms and dissections – What we learn from decellularization and scanning electron microscopy

PLoS ONE ◽

10.1371/journal.pone.0213794 ◽

2019 ◽

Vol 14 (3) ◽

pp. e0213794 ◽

Cited By ~ 3

Author(s):

Teresa Mimler ◽

Clemens Nebert ◽

Eva Eichmair ◽

Birgitta Winter ◽

Thomas Aschacher ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Extracellular Matrix ◽

Aortic Aneurysms ◽

Scanning Electron

Download Full-text

Cobalt Based Alloys for Dental Applications

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.583.175 ◽

2013 ◽

Vol 583 ◽

pp. 175-178 ◽

Cited By ~ 5

Author(s):

Brandusa Ghiban ◽

Cristina Maria Borţun ◽

Alexandru Ghiban ◽

Nicolae Ghiban

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Behaviour ◽

Structural Features ◽

Molybdenum Content ◽

Cobalt Alloys ◽

Mo Content ◽

Dental Applications ◽

Scanning Electron

The present paper put in evidence the mechanical behaviour of some commercial dental cobalt alloys, after own classification. The experimental cobalt alloys were classified in according either with molybdenum content, or with Cr+Mo content. A hierarcy of the alloys was finally made. The fractographic surfaces were investigate both by stereomacroscopy and scanning electron microscopy, putting in evidence the main structural features.

Download Full-text

Field Emission Scanning Electron Microscopy Studies of Industrial Polymers - A Survey

Microscopy and Microanalysis ◽

10.1017/s1431927600024193 ◽

1998 ◽

Vol 4 (S2) ◽

pp. 814-815

Author(s):

E.F. Osten ◽

M.S. Smith

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Field Emission ◽

Low Voltage ◽

Structural Features ◽

X Ray Diffraction ◽

Styrene Acrylonitrile ◽

Microscopy Techniques ◽

Scanning Electron

We are using the term "Industrial Polymers" to refer to polymers [plastics] that are produced by the ton or (in the case of films) by the mile. For example, in descending order of world-wide use (tonnage), the top eight of these polymers are polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), styrene polymers (including polystyrene - PS, and acrylonitrile-butadienestyrene/ styrene-acrylonitrile - ABS/SAN), polyesters (PETP), polyurethane (PU), phenolics and aminoplastics.Industrial polymers, which have been produced by the millions of tons for the last five decades and are of obvious social and economic importance, have been exhaustively characterized. Structural features which affect physical properties and indicate process variables have been studied by many techniques other than microscopy (x-ray diffraction, thermal analysis, rheology, chromatographies, etc.). Microscopy techniques for polymer characterization have been well documented. Our motivation to apply field emission (high resolution) scanning electron microscopy to the study of polymers is: (1) The application of low voltage, high resolution SEM to biological materials is well characterized.

Download Full-text

A new standardized-automatic method for bone-to-implant contact histomorphometric analysis based on backscattered scanning electron microscopy images

Clinical Oral Implants Research ◽

10.1111/clr.12129 ◽

2013 ◽

Vol 25 (6) ◽

pp. 702-706 ◽

Cited By ~ 7

Author(s):

Carolina Manresa ◽

Manel Bosch ◽

María Cristina Manzanares ◽

Patricia Carvalho ◽

José Javier Echeverría

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Automatic Method ◽

Histomorphometric Analysis ◽

Bone To Implant Contact ◽

Backscattered Scanning Electron Microscopy ◽

Microscopy Images ◽

Scanning Electron

Download Full-text

Uranium-bearing stratiform organic matter in paleoplacers of the lower Huronian Supergroup, Elliot Lake – Blind River region, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e85-209 ◽

1985 ◽

Vol 22 (12) ◽

pp. 1930-1944 ◽

Cited By ~ 28

Author(s):

Tylon O. Willingham ◽

Bartholomew Nagy ◽

Lois Anne Nagy ◽

David H. Krinsley ◽

David J. Mossman

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Organic Matter ◽

Local Development ◽

Analytical Data ◽

High Vacuum ◽

Gas Chromatography Mass Spectrometry ◽

River Region ◽

Backscattered Scanning Electron Microscopy ◽

Scanning Electron

The Elliot Lake – Blind River, Ontario, paleoplacer deposits in the basal Matineda Formation, lowermost member of the 2.25–2.45 Ga old Huronian Supergroup, contain organic matter chemically consistent with kerogen. This substance is also referred to as thucholite. Uranium ores and some gold occur here, and these minerals may be in close association with the kerogen. Two uraniferous and auriferous stratiform kerogens, obtained from the Denison Mines Limited's Denison mine and Rio Algom Limited's Stanleigh mine, have been analyzed by combined high-vacuum pyrolysis – gas chromatography – mass spectrometry and by neutron activation. The reflectances of these samples have also been determined. Related samples containing dispersed kerogen have been examined by backscattered scanning electron microscopy. The polymer-like matrix of the two stratiform kerogens consists of aromatic, alkyl aromatic hydrocarbon, and sulphur moieties and contains 20 and 32% uranium with gold abundances in the parts per billion range. The reflectances of the two stratiform kerogens are generally higher than those of the dispersed kerogens; the atomic H/C ratios of the former are −0.6 and −0.4. Backscattered scanning electron microscopy and petrographic observations reveal a complex diagenetic history. Stratigraphic position and supportive analytical data suggest that the stratiform kerogens were probably derived from ancient mats of cyanobacteria, subjected to various radiation-induced reactions, and, at least in part, were affected in a manner similar to the surrounding rocks. The latter experienced physical and chemical diagenetic reactions, which often caused repeated mineral fracturing and led to the local development of authigenic carbonates and feldspar. Some of the chemical nature and history of the stratiform kerogens resemble those of the Witwatersrand carbon seam kerogens.

Download Full-text