Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small, rounded vesicles with a dense core of amorphous material were observed in all cell types in the young rat aorta, that is, endothelial cells, smooth muscle cells and fibroblasts. They were particularly numerous in the Golgi complex but were also found in the cell periphery. The content of the vesicles had staining characteristics identical to those of elastin. Material of the same type was also found in cisternae on the maturing side of the dictyosomes and in vesicles budding from them. Reaction product for thiamine pyrophosphatase was present in both these structures, indicating that the Golgi complex is responsible for the formation of the dense-cored vesicles. This was further supported by the absence of reaction product for acid phosphatase in the cisternae and in the vesicles. Moreover, no uptake of exogenous markers was noted in the latter. On the basis of these findings it is suggested that the dense-cored vesicles have a secretory function and contain precursors of elastin. Elongated vesicles or profiles containing collagen fibrils were observed in smooth muscle cells and fibroblasts. In the cell periphery, these vesicles were often found to communicate with the extracellular space. Further inside the cells, they showed a close spatial relationship to the Golgi complex. Neither thiamine pyrophosphatase nor acid phosphatase activity was demonstrated in the elongated vesicles. Like the plasma membrane, their limiting membrane was positively stained for alkaline phosphatase. On the basis of these findings and the absence of uptake of exogenous markers in them, it is suggested that the elongated vesicles represent a means for collagen secretion in the growing aortic wall. The Golgi complex is believed to be involved in the transfer of collagen to these vesicles.
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PMID:Electron microscopic and cytochemical studies of rat aorta. Intracellular vesicles containing elastin- and collagen-like material. 21 9

Intoxication of rats with mercuric chloride (0.5 mg Hg/kg of body weight, daily for 10 weeks) increased the hepatic contents of soluble and insoluble collagen and elastin. The increase was associated with elevated serum aminotransferase and alkaline phosphatase activities, and decreased total protein level in serum. Inflammatory changes were found in the liver. An increase in the fibrous protein content suggests that inflammatory reaction to mercuric chloride can result in hepatic fibrosis.
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PMID:Collagen and elastin in the liver of rats intoxicated with mercuric chloride. 239 95

The bovine testis has a central mediastinum consisting of longitudinally oriented rete channels and spacious lymph vessels, embedded in the mediastinal stroma. The latter represents a contractile-elastic unit and is composed of myofibroblasts, collagen bundles and accumulations of elastin, connecting the myofibroblasts. The dimension of the mediastinum varies in cross sections at different levels between 3.5 and 31.8 mm2. In one cross section approximately 30 rete channels and approximately 30 openings of straight testicular tubules are encountered. Nearly 25% of the area is occupied by thin-walled, valveless lymph vessels. Arterial convolutes, interpolated between straight centripetal and straight centrifugal branches of the testicular artery flank the rete on all sides. It is concluded that the pulsation within these convolutes together with the contractile-elastic stroma promotes lymph and rete content in a caudo-cranial direction. Chordae retis as described by Roosen-Runge and Holstein (1978) for the human testis are a common feature in the bovine mediastinum testis. The rete channels are lined by a simple cuboidal or columnar epithelium. Short intraepithelial crypts are present and function as epithelial reserve for dilatation and expansion of the rate. The inventory of organelles is rather inconspicuous in the rete epithelium. The apical border bears short microvilli and gives a strong reaction for alkaline phosphatase. The basal cytoplasm contains many small to medium-sized electron-dense bodies and is site of a strong acid phosphatase reaction. The rete epithelium as a whole reacts strongly with leucine aminopeptidase, the marker enzyme of the testicular excurrent duct system. Many free mononuclear cells, mostly macrophages, are observed in the basal half of the rete epithelium.
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PMID:The mediastinum of the bovine testis. 273 7

A comparative light microscopy, histoenzymological and ultrastructural study enabled the authors, in a case of invasive lobular carcinoma of the breast, to emphasise certain special morphological traits of this tumour type and to make a contribution to the understanding of its histogenesis. By light microscopy, the only special features of the case were the abundance of mucus secreting tumour cells in the perilobular infiltrating zones and in the stromal texture with marked perigalactophoric hyalinosis and active elastic neogenesis. From an ultrastructural standpoint, intralobular malignant zones contained epithelial type cells, rich in microfilaments and with numerous desmosomal junctions. Two other cell types were identified at the periphery of the lobules. On consisted of round cells with intracytoplasmic cavities filled with mucus (signet ring cells). This group, in common with the intralobular cells, contained abundant amounts of alkaline phosphatase. The other consisted of elongated "pseudo-fibroblastic" cells, rich in microfibrils and in granular ergastoplasm with secretion at points of contact of collagen and elastin. These cells showed marked ATPase activity. They no doubt represented "hybrid" cells, intermediate in terms of their morphology and enzyme activity between myoepithelial and epithelial cells. These findings would thus appear to offer arguments in favour of the double cell origin -- duct and myoepithelial -- of lobular carcinoma.
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PMID:[Histogenesis of lobular cancer of the breast. Histoenzymatic and ultrastructural study of a muciparous cell invasive epithelioma]. 625 29

Ultrathin sections from the dermis of five normal subjects and from 10 patients suffering from pseudoxanthoma elasticum (PXE) were analyzed by immunoelectron microscopy with the aim of identifying and localizing proteins associated with the mineral precipitates within the altered elastic fibers. Serial sections were processed by indirect immunogold cytochemistry using primary antibodies against human fibronectin, vitronectin, bone sialoprotein, alkaline phosphatase, osteonectin, and osteopontin. In the latter two cases, antibodies against synthetic peptides were also used. The results indicate that normal elastic fibers contained osteopontin, and that this protein was associated with the apparently normal elastin as well as with the needle-shaped mineral precipitates in the elastic fibers of patients. On the contrary, significant amounts of vitronectin, alkaline phosphatase and, less, of bone sialoprotein were associated with the polymorphous mineral precipitates inside the elastic fibers. Large amounts of osteonectin and fibronectin, together with vitronectin, were localized on the microfilament aggregates, which were often associated with altered elastic fibers in PXE dermis and were never visualized in the dermis of control subjects. The results seem to indicate once more that PXE is a complex disorder of the fibroblast synthetic control. Elastic fiber mineralization might be considered a secondary event, which could depend on the abnormal synthesis and accumulation within the elastic fibers of proteins that are normally involved in mineralization processes.
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PMID:Matrix proteins with high affinity for calcium ions are associated with mineralization within the elastic fibers of pseudoxanthoma elasticum dermis. 857 19

Elastin molecules aggregate in the extracellular space where they are crosslinked by stable desmosine bridges. The resulting polymer is structurally organized as branched fibers and lamellae, which, in skin, are wider (a few microns) in the deep dermis and become progressively thinner (fraction of a micron) towards the papillary dermis. Several general and local factors seem to regulate elastin gene expression, deposition and degradation. In skin, the volume density of the elastin network increases from birth up to maturity, when it accounts for about 3-4% of the tissue. However, its amount and distribution depend on dermis areas, which are different among subjects and change with age. Several matrix molecules (glycosaminoglycans, decorin, biglycan, osteopontin) have been found to be associated with elastin into the normal fiber, and several others have been recognized within pathologic elastic fiber (osteonectin, vitronectin, alkaline phosphatase in PXE). With age, and in some pathologic conditions, skin elastin may undergo irreversible structural and compositional changes, which seem to progress from localized deposition of osmiophilic materials to the substitution of the great majority of the amorphous elastin with interwoven filaments negative for elastin specific antibodies.
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PMID:Elastic fiber during development and aging. 929 92

The chemical interaction that condenses the hyperphosphorylated protein tau in Alzheimer's disease (AD P-tau) into neurofibrillary tangles and cripples synaptic transmission remains unknown. Only beta-sheet, positive ion salt bridges between phosphates, and hydrophobic association can create tangles of just AD P-tau. We have correlated transmission electron microscope (TEM) images of tau aggregation with different percentages of beta-sheet in aqueous suspensions of tau while using buffers that block dispositive or tripositive ionic bridges between intermolecular phosphates. Circular dichroism (CD) studies were performed at different temperatures from 5-85 degrees C using AD P-tau, AD P-tau dephosphorylated with hydrofluoric acid (HF AD P-tau) or alkaline phosphatase (AP AD P-tau), and recombinant human tau with 3-repeats and two amino terminal inserts (R-39) and using bovine tau (B tau) isolated without heat or acid treatment. Secondary structure was estimated from CD spectra at 5 degrees C using the Lincomb algorithm. Each preparation except one demonstrated an inverse temperature transition, Ti, in the CD at 197 nm. No correlation was found between beta-sheet content and aggregation, leaving only hydrophobic interaction as the remaining possibility. Thirteen of 21 possible phosphorylation sites in AD P-tau lie adjacent to positive residues in tau's primary structure. Occupation of five to nine phosphate sites on AD P-tau appears sufficient to reduce or neutralize tau's basic character. AD P-tau's hydrophobic character is indicated by its low inverse temperature transition, Ti. The Ti for AD P-tau was 24.5 degrees C or 28 degrees C, whereas for B tau with three phosphates it was 32 degrees C, for unphosphorylated tau R-39 it was 38 degrees C, and for dephosphorylated HF AD P-tau it was 37.5 degrees C. The hydrophobic protein elastin and its analogs coalesce and precipitate at their Ti of 24-29 degrees C, well below body temperature. We hypothesize that AD P-tau causes tangle accumulation by this mechanism.
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PMID:Alzheimer disease hyperphosphorylated tau aggregates hydrophobically. 932 57

Patterning, cellular differentiation, and developmental sequences of dermal denticles (denticles) are described for the skate Leucoraja erinacea. Development of denticles proceeds caudo-rostrally in the tail and trunk. Once three rows of denticles form in the tail and trunk, denticles begin to appear in the region of the pelvic girdle, medio-caudal to the eyes and on the pectoral fins. Although timing of cellular differentiation of denticles differs among different locations of the body, cellular development of a denticle is identical in all locations. Thickening of the epidermis as a denticle lamina marks initiation of development. A single lamina for each denticle forms, and a small group of mesenchymal cells aggregates underneath it. The lamina then invaginates caudo-rostrally to form the inner- and outer-denticle epithelia (IDE and ODE, respectively). Before nuclei of IDE cells are polarized, enameloid matrix appears between the basement membrane of the IDE and the apical surface of the pre-odontoblasts. Pre-dentin is then laid down along with collagenous materials. Von Kossa stain visualizes initial mineralization of dentin, but not enameloid. During the growth of a denticle, dense fibrous connective tissue of the dermis forms the deep dermal tissue over the dorsal musculature. Attachment fibers and tendons anchor denticles and dorsal musculature, respectively, on deep dermal tissue. Basal tissue of the denticles develops as the denticle crown grows. If the basal tissue is bone of attachment, then the cells along the basal tissue would be osteoblasts. However, these cells could not be distinguished from odontoblasts using immunolocalization of type I pro-collagen (Col I), alkaline phosphatase (APase), and neural cell adhesion molecule (N-CAM). Well-developed dentin, (not pre-dentin), the enameloid matrix (probably when it begins to mineralize), and deep dermal tissue are Verhoeff stain-positive, suggesting that these tissues contain elastin and/or elastin-like molecules. Our study demonstrates that the cellular development of denticles resembles tooth development in elasmobranchs, but that dermal denticles differ from teeth in forming from a single denticle lamina. Whether the basal tissue of denticles is bone of attachment remains undetermined. Confirmation and function of Verhoeff-positive proteins in enameloid, dentin, and deep dermal tissue remain to be determined. We discuss these issues along with an analysis of recent findings of enamel and enameloid matrices.
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PMID:Development of dermal denticles in skates (Chondrichthyes, Batoidea): patterning and cellular differentiation. 1039 24

The elastin-binding proteins EbpS of Staphylococcus aureus strains Cowan and 8325-4 were predicted from sequence analysis to comprise 486 residues. Specific antibodies were raised against an N-terminal domain (residues 1-267) and a C-terminal domain (residues 343-486) expressed as recombinant proteins in Escherichia coli. Western blotting of lysates of wild-type 8325-4 and Newman and the corresponding ebpS mutants showed that EbpS migrated with an apparent molecular mass of 83 kDa. The protein was found exclusively in cytoplasmic membrane fractions purified from protoplasts or lysed cells, in contrast to the clumping factor ClfA, which was cell-wall-associated. EbpS was predicted to have three hydrophobic domains H1-(205-224), H2-(265-280), and H3-(315-342). A series of hybrid proteins was formed between EbpS at the N terminus and either alkaline phosphatase or beta-galactosidase at the C terminus (EbpS-PhoA, EbpS-LacZ). PhoA and LacZ were fused to EbpS between hydrophobic domains H1-H2 and H2-H3, and distal to H3. Expression of enzymatic activity in E. coli showed that EbpS is an integral membrane protein with two membrane-spanning domains H1 and H3. N-terminal residues 1-205 and C-terminal residues 343-486 were predicted to be exposed on the outer face of the cytoplasmic membrane. The ligand-binding domain of EbpS is known from previous studies to be present in the N terminus between residues 14-34 and probing whole cells with anti-EbpS1-267 antibodies indicated that this region is exposed on the surface of intact cells. This was also confirmed by the observation that wild-type S. aureus Newman cells bound labeled tropoelastin whereas the ebpS mutant bound 72% less. In contrast, the C terminus, which carries a putative LysM peptidoglycan-binding domain, is not exposed on the surface of intact cells and presumably remains buried within the peptidoglycan. Finally, expression of EbpS was correlated with the ability of cells to grow to a higher density in liquid culture, suggesting that EbpS may have a role in regulating cell growth.
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PMID:The elastin-binding protein of Staphylococcus aureus (EbpS) is expressed at the cell surface as an integral membrane protein and not as a cell wall-associated protein. 1168 86

The localized expression of a number of extracellular matrix genes was evaluated over time in a novel rat rotator cuff injury model. The supraspinatus tendons of rats were severed at the bony insertion and repaired surgically. The healing response was evaluated at 1, 2, 4, and 8 weeks post-injury using histologic and in situ hybridization techniques. Expression patterns of collagens (I, II, III, IX, X, XII), proteoglycans (decorin, aggrecan, versican, biglycan, fibromodulin), and other extracellular matrix proteins (elastin, osteocalcin, alkaline phosphatase) were evaluated at the healing tendon to bone insertion site. Histologic results indicate a poor healing response to the injury, with only partial recreation of the insertion site by 8 weeks. In situ hybridization results indicate a specific pattern of genes expressed in each zone of the insertion site (i.e., tendon, fibrocartilage, mineralized cartilage, bone). Overall, expression of collagen types I and XII, aggrecan, and biglycan was increased, while expression of collagen type X and decorin was decreased. Expression of collagen type I, collagen type XII, and biglycan decreased over time, but remained above normal at 8 weeks. Results indicate that the rat supraspinatus tendon is ineffective in recreating the original insertion site, even at 8 weeks post-injury, in the absence of biological or biomechanical enhancements.
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PMID:The localized expression of extracellular matrix components in healing tendon insertion sites: an in situ hybridization study. 1203 18


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