scholarly journals Ultrastructural localization of calcium-activated adenosine triphosphatase (Ca2+-ATPase) in growth-plate cartilage.

1985 ◽  
Vol 33 (9) ◽  
pp. 925-932 ◽  
Author(s):  
T Akisaka ◽  
C V Gay
Keyword(s):  
Plasma Membrane ◽  
Enzymatic Activity ◽  
Growth Plate ◽  
Golgi Complex ◽  
Adenosine Triphosphatase ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Vesicle Membranes

The electron-microscopic cytochemical localization of calcium-activated adenosine triphosphatase (Ca2+-ATPase) was determined in chick epiphyseal growth-plate cartilage. In the reserve zone, mitochondria and lysosomes contained substantial amounts of reaction product, while the plasma membrane and the Golgi complex showed very weak enzymatic activity, and matrix vesicle membranes did not exhibit the cytochemical reaction. As maturation proceeded, the plasma membrane, Golgi complex, and matrix vesicle membranes also stained and were most intense in the proliferative and early hypertrophic zones. From the hypertrophic to the calcifying zone, cytochemical staining decreased progressively in the plasma membrane, the Golgi complex, and lysosomes, while in some cases mitochondrial reaction product remained intense. Matrix vesicles lost their enzymatic activity at the same time that matrix vesicle calcification commenced. It is proposed that this event allows matrix vesicles to calcify, since efflux of calcium would no longer occur.

scholarly journals Ultrastructural demonstration of increased sulfated proteoglycans and calcium associated with chondrocyte cytoplasmic processes and matrix vesicles in rat growth plate cartilage.

1989 ◽  
Vol 37 (7) ◽  
pp. 1025-1033 ◽  
Author(s):  
M Takagi ◽  
T Sasaki ◽  
A Kagami ◽  
K Komiyama
Keyword(s):  
Growth Plate ◽  
Close Association ◽  
Freeze Substitution ◽  
Matrix Vesicles ◽  
Immunoperoxidase Staining ◽  
Cytoplasmic Process ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Cytoplasmic Processes ◽  
Sulfated Proteoglycans

A monoclonal antibody (3-B-3) to chondroitin 6-sulfated proteoglycan was used with immunoperoxidase electron microscopy to study the relationship of chondrocyte cytoplasmic processes and matrix vesicles in rat epiphyseal growth plate cartilage. Immunoperoxidase staining of the chondrocyte plasmalemma was found at all levels in the growth plate and was most prominent in the hypertrophic zone. The plasmalemma and matrix of the cytoplasmic process often demonstrated stronger reactivity than the remainder of the cell surface. Matrix vesicles showed weak to strong surface or internal reactivity. The majority of them stained very similarly to the cytoplasmic process. X-ray microanalysis of specimens processed by rapid freezing and freeze substitution confirmed that both sulfur and calcium were localized within or in close association with both the cytoplasmic process and the matrix vesicle, suggesting a chemical combination of calcium with sulfated proteoglycans at both sites. These results indicate that there is a selective increase in the concentration of membrane-associated sulfated proteoglycan and calcium in the cell process, from which matrix vesicles may be released into the extracellular matrix.

scholarly journals Electron microscopic localization of adenosine triphosphate (ATP)-hydrolyzing activity in isolated matrix vesicles and reconstituted vesicles from calf cartilage.

1983 ◽  
Vol 31 (4) ◽  
pp. 462-470 ◽  
Author(s):  
S Kanabe ◽  
H H Hsu ◽  
R N Cecil ◽  
H C Anderson
Keyword(s):  
Atpase Activity ◽  
Phosphatase Activity ◽  
Adenosine Triphosphatase ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Epiphyseal Growth Plate ◽  
Vesicle Membrane ◽  
Electron Microscopic ◽  
The Matrix ◽  
Electron Microscopic Localization

The presence and distribution of adenosine triphosphatase (ATPase) activity in isolated matrix vesicles and reconstituted vesicles from fetal calf epiphyseal growth plate cartilage was studied by electron microscopic cytochemical methods to determine whether phosphatase activity would be found concentrated on the inside or the outside of matrix vesicle membranes or on both sides, and whether reconstitution of vesicles from deoxycholate-solubilized substituents would lead to the reassembly of membranes with ATPase incorporated. ATPase activity was observed on both the outer and inner surfaces of the investing membranes of isolated matrix vesicles and reconstituted vesicles. A transmembrane location of ATPase could indicate phosphate transfer across the vesicle membrane. Orthophosphate released by phosphatase activity within the protected microenvironment of the matrix vesicle could combine with membrane- or lipid-bound calcium, known to be present in vesicles, to form the first hydroxyapatite mineral during calcification.

Freeze-etch studies of epiphyseal growth plate cartilage reveal matrix vesicles associated with calcification

1978 ◽  
Vol 36 (2) ◽  
pp. 670-671
Author(s):  
Russell N. A. Cecil ◽  
H. Clarke Anderson
Keyword(s):  
Chromic Acid ◽  
Light And Electron Microscopy ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Glycerol Solution ◽  
Sprague Dawley ◽  
Epiphyseal Growth Plate ◽  
Growth Plates ◽  
Sprague Dawley Rats ◽  
Tibial Epiphyseal

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.

Effects of Hypophysectomy on the Occurrence and Calcifiability of Matrix Vesicles in the Epiphyseal Growth Plate of Immature Rats

1980 ◽  
Vol 38 ◽  
pp. 578-579
Author(s):  
S. I. Coleman ◽  
W. J. Dougherty
Keyword(s):  
Growth Plate ◽  
Matrix Vesicles ◽  
Epiphyseal Growth Plate ◽  
Hard Tissue ◽  
Hormonal Factors ◽  
Post Surgery ◽  
Mineral Deposition ◽  
Thin Sectioning ◽  
Integral Role ◽  
Cellular Secretion

In the cellular secretion theory of mineral deposition, extracellular matrix vesicles are believed to play an integral role in hard tissue mineralization (1). Membrane limited matrix vesicles arise from the plasma membrane of epiphyseal chondrocytes and tooth odontoblasts by a budding process (2, 3). Nutritional and hormonal factors have been postulated to play essential roles in mineral deposition and apparently have a direct effect on matrix vesicles of calcifying cartilage as concluded by Anderson and Sajdera (4). Immature (75-85 gm) Long-Evans hooded rats were hypophysectomized by the parapharyngeal approach and maintained fourteen (14) days post-surgery. At this time, the animals were anesthetized and perfusion fixed in cacodylate buffered 2.5% glutaraldehyde. The proximal tibias were quickly dissected out and split sagittally. One half was used for light microscopy (LM) and the other for electron microscopy (EM). The halves used for EM were cut into blocks approximately 1×3 mm. The tissue blocks were prepared for ultra-thin sectioning and transmission EM. The tissue was oriented so as to section through the epiphyseal growth plate from the zone of proliferating cartilage on down through the hypertrophic zone and into the initial trabecular bone. Sections were studied stained (double heavy metal) and unstained.

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