Backscattered Electron Imaging of the Calcified Tissues Present in Bone Healing

SummaryThe aspect of calcified tissues involved in fracture healing was studied by means of backscattered electron imaging. Bilateral transverse midshaft osteotomies were performed in the tibiae of 16 dogs. The osteotomies were reduced by means of a type II external skeletal fixator, and the clinical and radiographic course was assessed weekly until the moment of euthanasia, one, two, four and eight weeks after the operations. The osteotomized areas were removed and their structure examined in the scanning electron microscope, using backscattered electron images, to determine the general aspect of the extracellular matrix of the calcified tissues present. Four different tissues were observed: lamellar bone, woven bone, calcified cartilage and chondroid tissue. The backscattered electron contrast and fibre arrangement of the matrix, as well as the size and shape of the cellular lacunae, allow identification of the tissue. Chondroid tissue, which seems to have a leading role in the early phases of fracture healing, shows a characteristic pattern of a highly calcified and fibrous matrix with a large number of irregular and confluent cell lacunae.The morphological characteristics of the calcified tissues involved in fracture healing were studied by means of backscattered electron imaging. Lamellar bone, woven bone, calcified cartilage and chondroid tissue were the four calcified tissues observed during the healing process of canine midshaft tibial experimental fractures.

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Back-Scattered Electron Imaging of a Non-Vertebral Case of Hypervitaminosis a in a Cat

Journal of Feline Medicine and Surgery ◽

10.1053/jfms.2000.0065 ◽

2000 ◽

Vol 2 (1) ◽

pp. 49-56 ◽

Cited By ~ 8

Author(s):

J Franch ◽

J Pastor ◽

B Franch ◽

I Durall ◽

M C Manzanares

Keyword(s):

Clinical Case ◽

Articular Surface ◽

Lamellar Bone ◽

Scattered Electron ◽

Hypervitaminosis A ◽

Woven Bone ◽

Chondroid Tissue ◽

Calcified Cartilage ◽

Electron Imaging ◽

Scanning Electron

We describe a clinical case of hypervitaminosis A in a cat. The main lesions were bony fusions of both the hip and stifle joints, without spinal involvement. A post-mortem study using back-scattered scanning electron microscopy (BEI-SEM) revealed that exostoses had formed around the joints without articular surface involvement. The more recently formed areas of bony proliferation were composed mainly of chondroid tissue surrounded by different degrees of woven bone. As the bony reaction occurred, remodelling of the trabeculae was observed which lead to progressive substitution of chondroid tissue by woven bone surrounded by apposition of lamellar bone. No traces of calcified cartilage were observed in any of the bone sections evaluated.

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High-sensitivity detection of gold labels by high-angle dark-field STEM imaging

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162028 ◽

1990 ◽

Vol 48 (3) ◽

pp. 892-893 ◽

Cited By ~ 1

Author(s):

Max T. Otten

Keyword(s):

High Sensitivity ◽

Dark Field ◽

Bright Field ◽

Backscattered Electron Imaging ◽

Backscattered Electrons ◽

Average Atomic Number ◽

Highly Sensitive ◽

Backscattered Electron ◽

Electron Imaging ◽

High Sensitivity Detection

Labelling of antibodies with small gold probes is a highly sensitive technique for detecting specific molecules in biological tissue. Larger gold probes are usually well visible in TEM or STEM Bright-Field images of unstained specimens. In stained specimens, however, the contrast of the stain is frequently the same as that of the gold labels, making it virtually impossible to identify the labels, especially when smaller gold labels are used to increase the sensitivity of the immunolabelling technique. TEM or STEM Dark-Field images fare no better (Figs. 1a and 2a), again because of the absence of a clear contrast difference between gold labels and stain.Potentially much more useful is backscattered-electron imaging, since this will show differences in average atomic number which are sufficiently large between the metallic gold and the stains normally used. However, for the thin specimens and at high accelerating voltages of the STEM, the yield of backscattered electrons is very small, resulting in a very weak signal. Consequently, the backscattered-electron signal is often too noisy for detecting small labels, even for large spot sizes.

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Enzyme histochemical application and backscattered electron imaging to visualize the distribution of lymphatic capillaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161965 ◽

1990 ◽

Vol 48 (3) ◽

pp. 880-881

Author(s):

Seiji Kato

Keyword(s):

Staining Method ◽

Double Staining ◽

Reaction Products ◽

Blood Capillaries ◽

Backscattered Electron Imaging ◽

Histochemical Observation ◽

Backscattered Electron ◽

Double Staining Method ◽

Electron Imaging ◽

Cryostat Sections

Previously, the author repeatedly confirmed the higher 5’-nucleotidase (5’-Nase) and lower alkaline phoaphatase (ALPase) activities in the wall of lymphatic capillaries reacted with the lead-based method relative to those of blood capillaries. The ALPase, on the other hand, is markedly higher in blood capillaries than in lymphatics. On the basis of these enzyme characteristics, the author has developed a 5’-Nase— ALPase double staining method to differentiate small lymphatics from blood capillaries at the level of the light microcsopy. Furthermore, we applied it to histochemical observation of the lead-containing reaction products of 5’-Nase in lymphatics on the same or adjacent cryostat sections using backscattered electron imaging (BEI) in scanning electron microscope (SEM). This paper presents a new applicability of 5’-Nase histochemistry by BEI-SEM to demonstrate the distribution of lymphatic capillaries in tissue blocks.

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Osteoconductive Properties of a Volume-Stable Collagen Matrix in Rat Calvaria Defects: A Pilot Study

Biomedicines ◽

10.3390/biomedicines9070732 ◽

2021 ◽

Vol 9 (7) ◽

pp. 732

Author(s):

Karol Alí Apaza Alccayhuaman ◽

Stefan Tangl ◽

Stéphane Blouin ◽

Markus A. Hartmann ◽

Patrick Heimel ◽

...

Keyword(s):

Extracellular Matrix ◽

Bone Formation ◽

Collagen Matrix ◽

Microcomputed Tomography ◽

Soft Tissue Augmentation ◽

Backscattered Electron Imaging ◽

Quantitative Backscattered Electron Imaging ◽

Rat Calvaria ◽

Backscattered Electron ◽

Electron Imaging

Volume-stable collagen matrices (VSCM) are conductive for the connective tissue upon soft tissue augmentation. Considering that collagen has osteoconductive properties, we have investigated the possibility that the VSCM also consolidates with the newly formed bone. To this end, we covered nine rat calvaria circular defects with a VSCM. After four weeks, histology, histomorphometry, quantitative backscattered electron imaging, and microcomputed tomography were performed. We report that the overall pattern of mineralization inside the VSCM was heterogeneous. Histology revealed, apart from the characteristic woven bone formation, areas of round-shaped hypertrophic chondrocyte-like cells surrounded by a mineralized extracellular matrix. Quantitative backscattered electron imaging confirmed the heterogenous mineralization occurring within the VSCM. Histomorphometry found new bone to be 0.7 mm2 (0.01 min; 2.4 max), similar to the chondrogenic mineralized extracellular matrix with 0.7 mm2 (0.0 min; 4.2 max). Microcomputed tomography showed the overall mineralized tissue in the defect to be 1.6 mm3 (min 0.0; max 13.3). These findings suggest that in a rat cranial defect, VSCM has a limited and heterogeneous capacity to support intramembranous bone formation but may allow the formation of bone via the endochondral route.

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