scholarly journals Localization of bone sialoprotein (BSP) to Golgi and post-Golgi secretory structures in osteoblasts and to discrete sites in early bone matrix.

1993 ◽  
Vol 41 (2) ◽  
pp. 193-203 ◽  
Author(s):  
P Bianco ◽  
M Riminucci ◽  
G Silvestrini ◽  
E Bonucci ◽  
J D Termine ◽  
...  
Keyword(s):  
Secretory Granules ◽  
Bone Matrix ◽  
Ultrastructural Level ◽  
Bone Sialoprotein ◽  
Protein Glycosylation ◽  
Secretory Structures ◽  
Mineral Deposition ◽  
The Matrix ◽  
Random Manner ◽  
Intracellular Labelling

Bone sialoprotein (BSP), a bone matrix-enriched glycoprotein containing the Arg-Gly-Asp (RGD) motif and endowed with cell binding properties, was localized in osteoblasts and early bone matrix of developing rat bone at the ultrastructural level. Preliminary light microscopic observations indicated that intracellular labelling was restricted to a paranuclear dot corresponding to the "negative Golgi image" of classical histology. The same pattern was observed whether antisera against the fully glycosylated protein or a peptide antiserum to a stretch of amino acids in human BSP sequence were employed. At the EM level, we obtained labeling over the Golgi area of osteoblasts but not over the rER. The labeling was concentrated over distensions of the trans Golgi and over pro-secretory granules. In the matrix, BSP was distributed in a non-random manner. The label was concentrated over spherical aggregates of finely fibrillar material corresponding to the sites of early mineral deposition (so-called "mineralization nodules"). Such BSP-positive foci were seen both close to and away from the cell surface. The predominant association of BSP with Golgi and post-Golgi secretory structures and its absence from rER, as well as the reproducibility of the same pattern of localization with different antisera, might indicate a slow transit of the protein through the Golgi, not necessarily associated with protein glycosylation.

scholarly journals Polyethyleneimine as a contrast agent for ultrastructural localization and characterization of proteoglycans in the matrix of cartilage and bone.

1991 ◽  
Vol 39 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Y M Sauren ◽  
R H Mieremet ◽  
C G Groot ◽  
H K Koerten ◽  
J P Scherft
Keyword(s):  
Bone Matrix ◽  
Ultrastructural Localization ◽  
Ultrastructural Level ◽  
Cartilage Matrix ◽  
Proteoglycan Synthesis ◽  
Positive Material ◽  
Calcified Cartilage ◽  
The Matrix ◽  
Proteoglycan Aggregates

We examined the presence of proteoglycans in the extracellular matrix of cartilage and bone in fetal mouse radii at the ultrastructural level, using the cationic dye polyethyleneimine (PEI). After staining with this dye, the proteoglycans appeared as granules in the uncalcified bone matrix and as extended winding structures in the cartilage matrix. PEI-positive material was removed after treatment of the tissue with chondroitinase ABC. Inhibition of the proteoglycan synthesis by beta-D-xyloside resulted in smaller PEI-positive windings in the cartilage matrix. These observations suggest that the winding, PEI-positive structures represent proteoglycan aggregates. No loss of PEI-positive material in the calcified cartilage matrix was seen, suggesting that proteoglycans do not need to be removed to make the matrix calcifiable.

scholarly journals Support of bone mineral deposition by regulation of pH

2018 ◽  
Vol 315 (4) ◽  
pp. C587-C597 ◽  
Author(s):  
Harry C. Blair ◽  
Quitterie C. Larrouture ◽  
Irina L. Tourkova ◽  
Li Liu ◽  
Jing Hao Bian ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Extracellular Space ◽  
Type I Collagen ◽  
Bone Matrix ◽  
Membrane Vesicles ◽  
Bone Collagen ◽  
Type I ◽  
Mineral Deposition ◽  
The Matrix ◽  
Ph Dependent

Osteoblasts secrete collagen and isolate bone matrix from extracellular space. In the matrix, alkaline phosphatase generates phosphate that combines with calcium to form mineral, liberating 8 H+ per 10 Ca+2 deposited. However, pH-dependent hydroxyapatite deposition on bone collagen had not been shown. We studied the dependency of hydroxyapatite deposition on type I collagen on pH and phosphate by surface plasmon resonance in 0–5 mM phosphate at pH 6.8–7.4. Mineral deposition saturated at <1 mM Ca2+ but was sensitive to phosphate. Mineral deposition was reversible, consistent with amorphous precipitation; stable deposition requiring EDTA removal appeared with time. At pH 6.8, little hydroxyapatite deposited on collagen; mineral accumulation increased 10-fold at pH 7.4. Previously, we showed high expression Na+/H+ exchanger (NHE) and ClC transporters in osteoblasts. We hypothesized that, in combination, these move protons across osteoblasts to the general extracellular space. We made osteoblast membrane vesicles by nitrogen cavitation and used acridine orange quenching to characterize proton transport. We found H+ transport dependent on gradients of chloride or sodium, consistent with apical osteoblast ClC family Cl−,H+ antiporters and basolateral osteoblast NHE family Na+/H+ exchangers. Little, if any, active H+ transport, supported by ATP, occurred. Major transporters include cariporide-sensitive NHE1 in basolateral membranes and ClC3 and ClC5 in apical osteoblast membranes. The mineralization inhibitor levamisole reduced bone formation and expression of alkaline phosphatase, NHE1, and ClC5. We conclude that mineral deposition in bone collagen is pH-dependent, in keeping with H+ removal by Cl−,H+ antiporters and Na+/H+-exchangers. Periodic orientation hydroxyapatite is organized on type I collagen-coiled coils.

scholarly journals Case Report and Ultrastructural Study of Intracranial Embryonal Carcinoma

1978 ◽  
Vol 5 (4) ◽  
pp. 447-450 ◽  
Author(s):  
Gerson Ejeckam ◽  
Margaret G. Norman ◽  
Leslie P. Ivan
Keyword(s):  
Germ Cell ◽  
Ultrastructural Study ◽  
Embryonal Carcinoma ◽  
Secretory Granules ◽  
Germ Cell Tumors ◽  
Cell Types ◽  
Ultrastructural Level ◽  
Embryoid Bodies ◽  
Differentiated Cells ◽  
Intermediate Cells

SUMMARY:A case of a primary intracranial embryonal carcinoma, the first with ultrastructural study, is reported. The tumor was associated with precocious puberty in a 6½-year-old female. Characteristic embryoid bodies were present. At the ultrastructural level three cell types were noted: undifferentiated, differentiated, and intermediate types. The undifferentiated showed scanty cytoplasmic organelles and numerous free polysomes, while the differentiated cells contained well-developed mitochondria, Golgi apparatus, rough endoplasmic reticulum, and some contained secretory granules. The intermediate cells possessed dilated and irregularly-shaped mitochondria but still retained large numbers of free polysomes. The authors suggest that intracranial germ cell tumors be named in conformity with germ cell tumors in other sites, and that terms such as “ectopic pinealoma” and “atypical teratoma of the pineal” be used no longer.

Disorders of bone

2018 ◽  
Author(s):  
Max Robinson ◽  
Keith Hunter ◽  
Michael Pemberton ◽  
Philip Sloan
Keyword(s):  
Alveolar Bone ◽  
Bone Biopsy ◽  
Bone Matrix ◽  
Polarized Light ◽  
Histological Section ◽  
Additional Time ◽  
Dental Procedures ◽  
The Matrix ◽  
Bony Lesions ◽  
Fibrous Membranes

Most invasive dental procedures involving removal of teeth or bone are followed by uneventful healing. However, dentists should be aware that generalized abnormalities of bone, such as osteoporosis and Paget’s dis­ease of bone, may complicate these procedures and, rarely, can lead to ongoing clinical problems. The effects of radiotherapy to the jaws and bisphosphonate treatment are well-described causes of osteonecrosis and delayed healing. Diagnosis of bone disorders often depends on integrating the results of clinical, imaging, pathological, genetic, and biochemical investigations. Although the bony skeleton is often thought of as forming just a rigid framework, it should be remembered that bone is a living, responsive tissue that plays an important role in metabolism. During development, some bones develop from a cartilaginous template and others, such as most of the craniofacial bones, form in fibrous membranes. Bone matrix is laid down by osteoblasts that are derived from the extensive meshwork of bone-lining cells that cover the bone surfaces. The bone matrix contains osteocytes that are responsive to mechanical stresses. Bone matrix is removed by osteoclasts that move over the bone sur­face, resulting in scalloped pits termed Howship’s lacunae. Bone mat­rix can be woven or lamellar in pattern. Pathologists often examine sections of bony lesions in polarized light to determine whether the pattern of the collagenous matrix is woven or lamellar, because it can be pivotal for diagnosis. It is also important for clinicians to be aware that, in order to produce a histological section of bone, the tissue must first be fixed and then demineralized to soften the matrix. When a bone biopsy is performed, the patient should be made aware that additional time will be needed to process the biopsy. Following extraction of a tooth, the socket rapidly fills with blood, which then clots. Granulation tissue, which consists of proliferating endothelial cells and fibroblasts derived from remnants of the periodontal ligament and surrounding alveolar bone, grows into the clot and organization commences. Osteoclasts begin to remodel the crestal bone and remove any small spicules of bone detached during the extraction.

scholarly journals Heterogeneity in the pattern of distribution of the specific hormonal product and secretogranins within the secretory granules of rat prolactin cells.

1994 ◽  
Vol 42 (8) ◽  
pp. 1097-1107 ◽  
Author(s):  
H Ozawa ◽  
R Picart ◽  
A Barret ◽  
C Tougard
Keyword(s):  
Subcellular Distribution ◽  
Secretory Granules ◽  
Culture Conditions ◽  
Male Rat ◽  
Immunogold Electron Microscopy ◽  
The Matrix ◽  
Granule Membrane ◽  
Adult Male Rat ◽  
Secretory Products ◽  
Rat Pituitary Tumor Cells

We investigated the subcellular distribution of secretogranins I, II (Sg I, Sg II), and prolactin (PRL) by double immunogold electron microscopy in GH3B6 rat pituitary tumor cells grown in different culture conditions and in normal PRL cells in adult male rat anterior pituitary. Co-localization of Sg I or Sg II with PRL was observed in most secretory granules in GH3B6 cells and normal PRL cells, except for some secretory granules containing only Sgs in GH3B6 cells and containing only PRL in normal PRL cells. In GH3B6 cells treated with thyrotropin-releasing hormone (TRH) for 2 hr, the newly formed small secretory granules within the Golgi zone contained preferentially immunoreactive PRL. Interestingly, when co-localized with PRL, Sgs (particularly Sg I) were observed at the periphery of the matrix of secretory granules in GH3B6 cells as well as in normal PRL cells, suggesting their possible interaction with the secretory granule membrane. The present study indicates a heterogeneous subcellular distribution of PRL, Sg I, and Sg II in individual secretory granules of GH3B6 cells and of normal PRL cells, pointing out the formation of different types of aggregates during the condensation of secretory products in these two PRL cell models.

scholarly journals Study of Endochondral Ossification in Human Fetalcartilage Anlagen of Metacarpals: Comparative Morphology of Mineral Deposition in Cartilage and in the Periosteal Bone Matrix

2018 ◽  
Vol 301 (4) ◽  
pp. 571-580 ◽  
Author(s):  
Ugo E. Pazzaglia ◽  
Marcella Reguzzoni ◽  
Francesca Pagani ◽  
Valeria Sibilia ◽  
Terenzio Congiu ◽  
...  
Keyword(s):  
Endochondral Ossification ◽  
Bone Matrix ◽  
Comparative Morphology ◽  
Mineral Deposition

scholarly journals Chromogranin A in the pancreatic islet: cellular and subcellular distribution.

1986 ◽  
Vol 34 (12) ◽  
pp. 1673-1682 ◽  
Author(s):  
M Ehrhart ◽  
D Grube ◽  
M F Bader ◽  
D Aunis ◽  
M Gratzl
Keyword(s):  
Pancreatic Islet ◽  
Subcellular Distribution ◽  
Chromogranin A ◽  
Chromaffin Cells ◽  
Protein A ◽  
Ultrastructural Level ◽  
Polyclonal Antiserum ◽  
Secretory Vesicles ◽  
The Matrix ◽  
Pancreatic Endocrine Cells

Chromogranin A (CGA) is the major soluble protein within secretory vesicles of chromaffin cells. A polyclonal antiserum was raised against bovine CGA and characterized in two-dimensional immunoblots. Cellular and subcellular distribution of CGA in bovine pancreatic islet was investigated by immunocytochemistry. At the light microscopic level, CGA-like immunoreactivity was found in the same cells that react with antibodies against insulin, glucagon, and somatostatin. A minority of cells containing pancreatic polypeptide also showed faint immunostaining. At the ultrastructural level (protein A-gold technique), CGA-like immunoreactivity was confined exclusively to the secretory vesicles. Whereas the hormones were localized mainly in the central part of the secretory vesicles, CGA was present predominantly in the periphery. These findings indicate that a CGA-like protein is a regular constituent of the matrix of secretory vesicles in pancreatic endocrine cells.

scholarly journals Ultrastructural localization of acidic glycoconjugates with the low iron diamine method.

1982 ◽  
Vol 30 (5) ◽  
pp. 471-476 ◽  
Author(s):  
M Takagi ◽  
R T Parmley ◽  
S S Spicer ◽  
F R Denys ◽  
M E Setser
Keyword(s):  
Bone Marrow ◽  
External Surface ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Ultrastructural Localization ◽  
Ultrastructural Level ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Electron Microscope Level ◽  
Thin Sections

The present study has applied the low iron diamine (LID) method at the ultrastructural level to demonstrate acid glycoconjugates. We have examined rat epiphyseal cartilage, human bone marrow, rat tracheal glands, and mouse sublingual glands stained with LID prior to embedment. The LID staining appeared to require postosmication for adequate visualization at the electron microscope level. Thiocarbohydrazide-silver proteinate (TCH-SP) staining of thin sections variably enhanced LID reactive sites. LID-TCH-SP stained carboxyl and sulfate groups of glycosaminoglycans in the extracellular cartilage matrix, secretory granules, and expanded Golgi saccules of chondrocytes. In human bone marrow, LID-TCH-SP variably stained the cytoplasmic granules, known to contain sulfated glycosaminoglycans, and the external surface of the plasma membrane of leukocytes. Moderately strong LID staining was observed in secretory granules in mucous tubules of rat tracheal glands, known to contain sulfated glycoproteins, and in acinar cells of mouse sublingual glands, known to contain a sialoglycoprotein. The lack of sulfated glycoconjugates in acinar cells of the mouse sublingual gland was confirmed by their failure to stain with the high iron diamine method. Thus these studies indicate that the LID and LID-TCH-SP methods are useful for the ultrastructural localization of carboxylated and sulfated glycoconjugates in extracellular and intracellular sites.

scholarly journals Immunohistochemical localization of procollagens. III. Type I procollagen antigenicity in osteoblasts and prebone (osteoid).

1981 ◽  
Vol 29 (7) ◽  
pp. 791-804 ◽  
Author(s):  
G M Wright ◽  
C P Leblond
Keyword(s):  
Bone Growth ◽  
Secretory Granules ◽  
Immunohistochemical Localization ◽  
Multivesicular Bodies ◽  
Type I ◽  
Frozen Sections ◽  
Type I Procollagen ◽  
The Matrix ◽  
Old Rats ◽  
Procollagen Iii

Frozen sections of unfixed tibia and mandibles from day-old rats were immunostained by the peroxidase-antiperoxidase technique after exposure to antisera against procollagen I or other collagenous materials. Light microscopic study of bone growth areas showed that procollagen I antigenicity was present in osteoblasts and prebone (osteoid), but not bone tissue; neither procollagen III nor collagen IV antigenicity were detected. The localization of procollagen I antigenicity within osteoblasts was then attempted in the electron microscope. Chopper slices of formaldehyde-fixed tibia from day-old rats were incubated with affinity-purified anti-procollagen I antibodies linked to peroxidase and were treated with hydrogen peroxide in the presence of 3,3'-diaminobenzidine. The dot-like reaction indicative of procollagen I antigenicity was found to be moderate in rough endoplasmic reticulum (rER) cisternae, strong in spherical and cylindrical Golgi distensions, and intense in prosecretory and secretory granules. Reactivity was also observed within the matrix of multivesicular bodies Thus an increasing gradient of procollagen I antigenicity occurs from rER cisternae through Golgi distensions to secretory granules, that is, along the presumed pathway of procollagen synthesis. The antigenicity present within rER cisternae is attributed to the precursor pro alpha (I) chains, while that in the cylindrical Golgi distensions, secretory granules, and prebone is attributed to procollagen itself. The antigenicity of multivesicular bodies suggests some degradation of pro alpha chains or procollagen.

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