scholarly journals Visualization of early intramembranous ossification by electron microscopic and spectroscopic imaging.

1984 ◽  
Vol 98 (3) ◽  
pp. 911-921 ◽  
Author(s):  
A L Arsenault ◽  
F P Ottensmeyer
Keyword(s):  
Calcium Phosphates ◽  
Spectroscopic Imaging ◽  
Longitudinal Axis ◽  
Mineral Deposits ◽  
Intramembranous Ossification ◽  
Local Formation ◽  
Electron Microscopic ◽  
Nucleation Sites ◽  
Sulfur Containing ◽  
Perichondrial Ring

We present electron microscopic and electron spectroscopic images of putative nucleation sites and early mineral deposits during intramembranous ossification of the murine perichondrial ring. Electron spectroscopic imaging (ESI) permits the quantitative determination and direct visualization of spatial distribution of atomic elements within specimens at high spatial resolution. In this study ESI was used to determine the elemental distributions of phosphorus, sulfur, and calcium. Nucleation and subsequent mineralization in the perichondrial ring occurred sequentially along the longitudinal axis. Proximal regions of the ring contained a matrix with only a few nucleation sites that are characterized in conventional electron micrographs as small loci of low-density material in which dense particles are located. Elemental maps of these sites that we obtained by ESI reveal a sulfur-containing matrix in which localized concentrations of phosphorus occur. With further maturation the loci became centers for the genesis of numerous dense rods or crystals. These mineral deposits contained increased concentrations of P, S, and Ca, compared with the surrounding matrix. The appearance of S at nucleation sites and its persistence in developing mineral deposits suggests that a sulfur-containing moiety may serve as a locus within the osteoid matrix to attain high local concentrations of Ca and P, which leads to the controlled local formation of calcium phosphates. Calcification of the perichondrial ring has been found to occur in the absence of matrix vesicles, which illustrates that these membrane-bounded organelles are not obligatory sites for nucleation in this matrix.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

scholarly journals Bacteriostatic Characteristics of Bone Substituting Constructors Obtained from Composite Materials Based on Natural Polymers, Calcium Phosphates and Vancomycin

2017 ◽  
Vol 24 (2) ◽  
pp. 48-56
Author(s):  
P. A Karalkin ◽  
N. S Sergeeva ◽  
V. S Komlev ◽  
I. K Sviridova ◽  
V. A Kirsanova ◽  
...  
Keyword(s):  
3D Printing ◽  
Calcium Phosphates ◽  
Aureus Strain ◽  
Diffusion Method ◽  
Skin Defect ◽  
Natural Polymers ◽  
Electron Microscopic ◽  
Study Results ◽  
Microscopic Evaluation

Introduction. The local delivery of therapeutic antibiotic concentrations to the zone of surgical intervention in bone pathology enables either to prevent or significantly decrease the rate of osteomyelitis development. It that study the efficacy of vancomycin inclusion and release from three dimensional constructors based on sodium alginate, gelatin and octacalcium phosphate and vancomycin intended for bone defect substitution was studied. Materials and methods . Prototyping of 3D constructors was performed by extrusion 3D printing. Various concentrations of vancomycin were added as an additional component at the stage of preparation of hydrogel (“ink”) for printing. Physical testing of the constructors included electron microscopic evaluation of their microstructure and porosity as well as the study of mechanical strength for compression and stretching. Functional activity of printed constructors with respect to the test strain S. aureus ATCC 6538-P was assessed by a disc-diffusion method in vitro and on the model of infected excision skin wound in rats - in vivo. Results . Analysis of the kinetic curves showed that the principal release of the drug in the model liquid took place within the first day. The total volume of the bound and released vancomycin made up approximately 20% of the calculated initial amount for all three concentrations. Formation of the marked growth inhibition zone of S. aureus strain in presence of vancomycin rich constructors was demonstrated in vitro. Insertion of constructors into the zone of infected skin defect resulted in a decrease of inflammatory processes severity and rate as well as accelerated the terms of complete wound healing. Conclusion. Study results showed the principle potentiality of bone substituting implants 3D-printing using multicomponent hydrogel compositions without change of separate components characteristics.

scholarly journals Elemental analysis of valvular and atherosclerotic calcification

2021 ◽  
Vol 10 (3) ◽  
pp. 26-33
Author(s):  
L. A. Bogdanov ◽  
N. Yu. Osyaev ◽  
Yu. D. Bogdanova ◽  
R. A. Mukhamadiyarov ◽  
A. R. Shabaev ◽  
...  
Keyword(s):  
Elemental Analysis ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Mineral Deposit ◽  
Mineral Deposits ◽  
Atherosclerotic Plaques ◽  
Aortic Valves ◽  
Nucleation Sites ◽  
Initial Nucleation ◽  
Backscattered Scanning Electron Microscopy

Aim. To analyze the topographic patterns of valvular and atherosclerotic calcification growth.Methods.           Dysfunctional aortic valves (n = 18) and atherosclerotic plaques (n = 20) were fixed in formalin, postfixed in 1% osmium tetroxide, consecutively stained by 2% osmium tetroxide and 2% uranyl acetate, and embedded into epoxy resin (Epon) with the further grinding and polishing ofthe samples. Upon the counterstaining by lead citrate and sputter coating with carbon, samples were visualized by backscattered scanning electron microscopy. Elemental analysis was conducted via energy-dispersive X-ray spectroscopy. Measurement of Ca/P ratio within the mineral deposits was carried out employing a pool table principle (i.e., in the center of the deposit, in the near and far circumferences (clockwise), and in control regions around the mineral deposit). Topographic patterns of calcifications were modeled using the correlation analysis.             Results. Significant correlation was revealed between the Ca/P ratio in the deposit center and in the near and far circumferences of deposit in both in valvular (r = 0,35-0,78 - near circumference; r = 0,63-0,69 - far circumference) and atherosclerotic mineral deposits (r = 0,37-0,56 - near circumference; r = 0,48-0,63 - far circumference), suggesting the hierarchical growth of cardiovascular calcification around the initial nucleation sites.Conclusion.       Valvular and atherosclerotic calcifications development is concentric.

Freeze-Drying-Embedding Method of Specimens For Analysis of Diffusible Elements by Electron Spectroscopic Imaging

1985 ◽  
Vol 43 ◽  
pp. 702-703
Author(s):  
G.T. Simon ◽  
E. Spitzer
Keyword(s):  
Freeze Drying ◽  
Spectroscopic Imaging ◽  
Analytical Techniques ◽  
Fixation Method ◽  
Primary Concern ◽  
Electron Spectroscopic Imaging ◽  
Critical Importance ◽  
Electron Microscopic ◽  
Quick Freezing ◽  
Entrance Velocity

Electron spectroscopic imaging (ESI), developed in the last decade by F. P. Ottensmeyer and his group is one of the most sensitive electron microscopic analytical techniques available today. Spatial resolutions of 0.5.m and mass resolution of 50 atoms or less can be achieved. The limitations of ESI resides in the fact that only very thin specimens (20nm in thickness) can be used. It is therefore impossible to analyze frozen-dried or frozen hydrated sections.The primary concern in analyzing diffusible elements is their extraction and translocation during processing. Already existing freeze-drying embedding techniques have been modified. Quick freezing is by far the fixation method of choice. The type of coolant and the entrance velocity are of critical importance. Vitrification layers of 25-30 microns can be obtained by plunging small fragments of tissue into liquid propane at an entrance velocity of more than 6.4 m/s.

Electron microscopic study of sperm head differentiation in the lizard Agama stellio

1987 ◽  
Vol 65 (12) ◽  
pp. 2959-2968 ◽  
Author(s):  
Hameed Al-Hajj ◽  
Suha Janakat ◽  
Fahmi Mahmoud
Keyword(s):  
Nuclear Envelope ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Longitudinal Axis ◽  
Sperm Head ◽  
Fibrous Layer ◽  
Electron Microscopic ◽  
Acrosomal Vesicle ◽  
Acrosomal Membrane ◽  
Chromatin Material

Early differentiation of the spermatid of Agama stellio is demonstrated by two anterior nuclear depressions, occupied by two proacrosomal vesicles, which fuse to form one vesicle. Later, this vesicle exhibits an acrosomal granule in its midposterior portion. The space between the posterior acrosomal membrane and the nuclear envelope is occupied by a subacrosomal fibrous layer which later exhibits a subacrosomal granule posterior to the acrosomal granule. The acrosomal vesicle and the nuclear depression flatten and later elongate. The acrosomal granule spreads and assumes the inverted V shape of the acrosomal vesicle, and the subacrosomal material assumes a feathery shape capping the nuclear prolongation. The subacrosomal granule on top of this feathery material forms a long, cross-striated subacrosomal rod which extends towards the tip of the acrosome. The chromatin material undergoes condensation into spirally oriented fibers, which eventually become homogeneous and dense. This process is accompanied by a change in the orientation of the manchette microtubules, which initially occur as rings around the nucleus and are eventually found parallel to the longitudinal axis of the nucleus.

Characterization of mesoporous calcium phosphates from calcareous marine sediments containing Si, Sr and Zn for bone tissue engineering

2016 ◽  
Vol 4 (42) ◽  
pp. 6842-6855 ◽  
Author(s):  
D. F. Silva ◽  
T. E. Friis ◽  
N. H. A. Camargo ◽  
Y. Xiao
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Marine Sediments ◽  
Calcium Phosphates ◽  
Mineral Deposits

Calcium phosphates (CAPs) can be produced from either biologically sourced materials or mineral deposits.

A Scanning Electron Microscopic study of hematite inclusions in cordierite porphyroblasts

1986 ◽  
Vol 44 ◽  
pp. 680-981
Author(s):  
J.N. Mitchell
Keyword(s):  
Metamorphic Rocks ◽  
Chemical Components ◽  
Retrograde Metamorphism ◽  
Electron Microscopic ◽  
Decomposition Products ◽  
Scanning Electron Microscopic Study ◽  
Nucleation Sites ◽  
Scanning Electron Microscopic ◽  
The Matrix ◽  
Rapid Diffusion

Porphyroblasts are monocrystalline to polycrystalline mineral grains in metamorphic rocks that are distinctly larger than the matrix grain surrounding them. Their presence reflects the metamorphic release and rapid diffusion of their chemical components, with subsequent crystallization at limited nucleation sites. Small inclusions of other minerals are often present in porphyroblasts, especially in members of the garnet group, staurolite, and cordierite. Various hypotheses may be suggested to explain such inclusions: (1) they are relics of earlier grains, either of the protolith or of a stage of metamorphism prior to porphyroblast growth; (2) they are reaction residues of the mineral grains that decomposed to form the porphyroblasts; or (3) they are decomposition products produced from the porphyroblasts by secondary or retrograde metamorphism.

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