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H C Anderson

Publications and source records attributed to H C Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1989

Mechanism of mineral formation in bone.

The mechanism of mineral formation in bone is seen best where active new bone formation is occurring, e.g., in newly forming subperiosteal bone of the embryo, in the growing bone of young animals, and in healing rickets where the calcification process in osteoid is reactivated. A large body of ultrastructural evidence, using conventional and anhydrous methods for tissue preparation, has shown convincingly that extracellular matrix vesicles are present at or near the mineralization front in all of the above, and that these vesicles are the initial site of apatite mineral deposition. Thus bone resembles growth plate cartilage, predentin, and turkey tendon in having calcification initiated by matrix vesicles. Once the calcification cascade is begun, matrix vesicles are no longer needed to support mineralization and are consumed by the advancing mineralization front in which performed crystals serve as nuclei for the formation of new crystals. The rate of crystal proliferation is promoted by the availability of Ca2+, PO4(3-), and the presence of collagen, and retarded by naturally occurring inhibitors of mineralization such as proteoglycans and several noncollagenous calcium-binding proteins of bone including bone-Gla protein (osteocalcin), phosphoproteins, osteonectin, and alpha-2HS-glycoproteins. New electron microscopic immunocytochemical findings in our laboratory suggest that the origin of alkaline phosphatase-positive bone matrix vesicles is polarized to the mineral-facing side of osteoblasts and may be concentrated near the intercellular junctions of human embryonic osteoblasts.

Alkaline Phosphatase↗
PubMed1989

Matrix vesicles and calcification of rachitic rat osteoid.

Tibiae from rachitic weanling rats were studied during healing to examine the mechanism of bone mineralization. Rickets was induced by feeding the animals a low phosphate, low vitamin D diet for five weeks. Calcification was reinstituted in three ways; group I animals received 1.0 ml of NaH2PO4 i.p. and the rachitogenic diet in a darkened room; group II animals were placed in a lighted room and given standard laboratory chow; group III animals were placed in lighted room, given standard laboratory chow and received 1.0 ml of 0.1M NaH2PO4 i.p. Group I healed slowly while II and III were found to heal rapidly and at nearly identical rates. Groups II and III revealed a significantly elevated serum alkaline phosphatase activity and became hyperphosphatemic as the rickets healed suggesting a more vigorous recovery. Ultrastructurally, numerous matrix vesicles were noted in unhealed rachitic bone matrix and these structures acquired mineral upon initiation of healing. Vesicle-associated mineral aggregates increased in size penetrating through and beyond the vesicle membrane and were incorporated into the advancing mineralization front. By 48 hrs. post-healing initiation, the osteoid borders were almost completely mineralized in groups II and III. These observations suggest that in addition to pre-existing mineral, matrix vesicles can also serve as nucleating sites in the osteoid of post-fetal bone.

Alkaline Phosphatase↗
PubMed1988

Purification and partial amino acid sequencing of alkaline phosphatase from rachitic rat epiphyseal cartilage.

1. Alkaline phosphatase of rachitic epiphyseal cartilage was purified to apparent homogeneity by sequential application of monoclonal affinity, DEAE-cellulose, and Sepharose CL-6B chromatography. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the enzyme showed the presence of a dominant band corresponding to a molecular weight of 80,000. 2. The N-terminal amino acid sequence was determined as follows: Phe-Val-Pro-Glu-Lys5-Glu-Lys-Asp-Pro-Ser10-Tyr-Trp-Arg-Gln-+ ++Gln15-Ala-Gln-Glu- Thr-Leu20-Lys-Asn-Ala-Leu-Lys25-Leu-Gln-Lys-?-Asn-Val-Asn-?- Ala-Lys35-?-Ile-?- Met-Phe40-Leu-(Gly?)-Asp-(Ala/Gly?)-Met45-?-Val-?- (Val/Gly?).

Alkaline Phosphatase↗
PubMed1988

The recruitment of pathology residents: a 1987 conference report on challenges and responses.

There is general agreement within pathology that there is a serious problem in the recruitment of US medical graduates into the field. Basic to this decline is inadequate exposure of medical students to the pathologist as a physician who is important to the care of patients and open to a range of clinical and research opportunities unparalleled in other medical specialties. Programs designed to increase the familiarity of students with pathology, both within the curriculum and outside of it, beginning before medical school and extending after medical school, have been proposed to reverse the downtrend in recruitment. Changes in the basic structure of pathology training programs, which would shorten the time commitment, are also considered important in increasing the attractiveness of a pathology career.

Foreign Professional Personnel↗
PubMed1988

Light microscopic localization of alkaline phosphatase in fetal bovine bone using immunoperoxidase and immunogold-silver staining procedures.

We localized alkaline phosphatase in the metaphyses of fetal bovine tibial bone by use of avidin-biotin-immunoperoxidase and immunogold-silver staining procedures. Low melting-point, paraffin-embedded sections of periodate lysine-paraformaldehyde-fixed undecalcified bone were used for immunostaining. We suggest that the combination of intact embryonic bone with this fixative and the immunohistochemical procedures used in this study may have helped to preserve antigenicity and thus to improve the efficiency of immunolabeling. Similar patterns of alkaline phosphatase localization were produced by the immunoperoxidase and immunogold-silver staining methods. The latter, although free of immunoreagents such as diaminobenzidine, must be monitored closely to avoid nonspecific staining during the silver enhancement procedure. Both methods revealed a concentration of the enzyme in osteoblasts and in areas of osteoid that lined the bone trabeculae. The results support the findings of earlier enzyme cytochemical studies in which osteoblasts were shown to have significant alkaline phosphatase activity.

Alkaline Phosphatase↗
PubMed1988

Mechanisms of pathologic calcification.

Pathologic calcification usually is initiated by the biologic membranes of mitochondria or matrix vesicles. Mitochondria frequently initiate intracellular calcification. Matrix vesicles, derived from the outer membrane of cells by budding or cell disruption, initiate extracellular calcification in calcific tendonitis, apatite-deposition osteoarthritis, atherosclerosis, cardiac valvular calcification, tympanosclerosis, and other calcific diseases. Matrix vesicles and mitochondria usually initiate calcification through the interaction of phosphatase enzymes with calcium-binding phospholipids, both of which are membrane-bound. Hydroxyapatite (HA) crystals are formed first within the protective microenvironment of the membrane-enclosed microspace. Once formed and exposed to the extracellular fluid, HA crystals can serve as nuclei or templates, thus supporting progressive, autocatalytic mineral crystal proliferation.

Arthritis↗
PubMed1988

Biomaterial-associated calcification: pathology, mechanisms, and strategies for prevention.

Deposition of calcium-containing apatite mineral occurs widely in association with cardiovascular and noncardiovascular medical devices and biomaterials, is the leading cause of failure of contemporary bioprosthetic heart valves, and limits the functional lifetime of experimental (and potentially clinical) mechanical blood pumps and polymeric heart valves. Calcification of bioprosthetic tissue is primarily intrinsic, related to cuspal connective tissue cells and fragments, and collagen. In contrast, the predominant site of calcific crystals on flexing polymeric surfaces in blood pumps or valve prostheses is extrinsic, associated with adherent cells, thrombus, or pseudointima. Pathologic calcification shares key features with physiologic skeletal mineralization, including crystal initiation through the mediation of cell membranes, usually in the form of extracellular vesicles. This suggests a unified hypothesis for normal and abnormal mineralization. Several approaches are being studied experimentally for the inhibition of bioprosthetic heart valve calcification. Controlled-release diphosphonate therapy, perhaps in conjunction with an anticalcification cuspal pretreatment, appears most effective. Research objectives in biomaterial-associated calcification include (1) development of animal models, (2) determination of initial crystal nucleation events and sites, (3) elucidation of the relative roles of host, implant, and mechanical determinants, and (4) development of approaches for the inhibition of mineralization.

Assisted Circulation↗
PubMed1987

Purification and partial amino acid sequencing of rat bone tumor (UMR106) alkaline phosphatase.

Cultured rat osteosarcoma (UMR106) alkaline phosphatase was purified to apparent homogeneity by sequential application of polyclonal antibody affinity, DEAE-cellulose, and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enzyme preparation treated with sodium dodecyl sulfate and mercaptoethanol showed the presence of a dominant band (using silver staining) corresponding to a molecular weight of 80,000. The amino acid composition was similar to those of various alkaline phosphatases. The N-terminal amino acid sequence was determined as follows: Phe-Val-Pro-Glu-Lys-Glu-Lys- Asp-Pro-Ser-Tyr-Trp-Arg-Gln-Gln-Ala-Gln-Glu-Thr-Leu- Lys-Asn-Ala-Leu-Lys-?-Gln-Lys-?-Asn-Val-Asn-Ala-Lys.

Alkaline Phosphatase↗
PubMed1987

Purification and partial amino acid sequencing of bovine kidney alkaline phosphatase.

Bovine kidney alkaline phosphatase (ALPase) was purified by the sequential application of monoclonal anti-bovine cartilage ALPase affinity, DEAE-cellulose, and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide-gel electrophoresis showed the presence of a single band corresponding to a molecular weight of 80,000. The N-terminal amino acid sequence of bovine kidney alkaline phosphatase was determined as follows: Leu-Val-Pro-Glu-Lys-Asp-Pro-?-Tyr-Trp-Arg-Asp-Gln-Ala-Gln.

Alkaline Phosphatase↗
PubMed1987

Purification of bone alkaline phosphatase from human osteosarcoma.

Purification of human bone alkaline phosphatase, derived from human osteosarcoma tissue, has been carried to electrophoretic homogeneity. The purification procedure involved three major steps: (1) chromatography on hydroxylapatite; (2) ion exchange chromatography; and (3) gel filtration. The resultant purified enzyme is a glycoprotein, has a molecular weight of approximately 80,000 (consistent with previous reports for the bone isoenzyme), and is characteristically inhibited by modest heat (56 degrees C, 30 min) and L-homoarginine but not by L-phenylalanine. The isolation and purification procedure described can lead to the production of significant amounts of highly purified bone alkaline phosphatase. Purified ALP can be used for an analysis of minor structural differences that appear to exist between the bone, liver and kidney isoenzymes. Such information could lead to the development of a clinical diagnostic procedure specifically for bone alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1986

Intracellular sorting and polarized cell surface delivery of (Na+,K+)ATPase, an endogenous component of MDCK cell basolateral plasma membranes.

Madin Darby Canine Kidney (MDCK) cells grown on polycarbonate filters in a two-chamber culture system were used to study the postsynthetic sorting of the alpha-subunit of the (Na+,K+)ATPase, an important native protein of the MDCK cell basolateral plasmalemmal domains. The N-azidobenzoyl derivative of ouabain (NAB-ouabain) and anti-ouabain antibodies were used in pulse labeling experiments to monitor the arrival of newly synthesized molecules of (Na+,K+)ATPase at the apical and basolateral cell surfaces. The results show that newly synthesized alpha-subunits bind NAB-ouabain and become substrates for immunoprecipitation only when this compound is present in the basolateral chamber. No more than 10% of the (Na+,K+)ATPase synthesized during the pulse period could appear at the apical surface without being detected by our assay. Thus, sorting of this native protein is effected intracellularly prior to its direct insertion into the basolateral plasmalemmal domain. Passage through an acidic compartment is not required for proper sorting.

Ammonium Chloride↗
PubMed1986

The deposition of calcium pyrophosphate by NTP pyrophosphohydrolase of matrix vesicles from fetal bovine epiphyseal cartilage.

About 5 mumol CaPPi/mg protein was deposited within 3 h in the presence of the reaction mixtures containing 1 mM ATP, 2 mM Ca2+, 1 mM Pi, and 17 micrograms of purified NTP pyrophosphohydrolase. At 1 mM ATP, 50% of the deposition was inhibited by 0.5-1 mM of various substrate and product analogues including AMP, ADP, and ethylene hydroxyl diphosphonate. The magnitude of inhibition on NTP pyrophosphohydrolase activity was in the order of AMP = CMP = ADP greater than adenosine greater than adenine greater than NAD = NADP. AMP, CMP, ADP, and adenosine are competitive inhibitors. The modes of inhibition by adenine, NAD, and NADP differ from the competitive inhibition. Ribose, 3'-AMP, 2'-AMP, and cAMP did not inhibit the enzyme activity.

Adenosine Triphosphate↗
PubMed1986

Development and cross-reactive properties of monoclonal antibodies to bovine matrix vesicle alkaline phosphatase.

Alkaline phosphatase (ALPase), concentrated in the membranes of matrix vesicles, is believed to play a role in initial calcification. To further purify, characterize, and identify this enzyme in tissue, a monoclonal antibody was developed against the ALPase of isolated fetal calf matrix vesicles. Splenic lymphocytes derived from mice immunized with Sepharose 6B-purified fetal calf matrix vesicle ALPase were fused with mouse plasmacytoma cells (line X63-Ag-8.653) using standard hybridoma technology. Hyperimmune sera and hybridoma culture supernatants were screened for the presence of specific antibody using a newly developed double-immunosorbent assay in which putative antibody is added to microtiter plate wells precoated with affinity-purified rabbit antimouse immunoglobulin. After incubation and washing, partially purified fetal calf matrix vesicle ALPase is added to each well. The enzyme adheres only to wells that contain specific anti-ALPase antibody. These wells are identified by adding the enzyme substrate p-nitrophenyl phosphate and reading the wells in a plate-reading spectrophotometer at 405 nm. A hybridoma-producing specific antibody was subsequently cloned and grown as ascities-producing tumors in pristane-primed mice. Ouchterlony analysis indicated that the cell line secretes an immunoglobulin of IgG1 class. This antibody reacts specifically with ALPase derived from calf matrix vesicles and cross-reacts with ALPase of bovine kidney, liver, and placental origin and human bone but does not cross-react with bovine intestinal ALPase or ALPase derived from matrix vesicles isolated from rachitic rat growth plate cartilage.

Alkaline Phosphatase↗
PubMed1986

Calcification in atherosclerosis. I. Human studies.

Early atherosclerotic lesions in human aortas less than five hours postmortem were studied by light microscopy (20 cases) and electron microscopy (10 cases), to determine the morphological and cytochemical character of calcium deposition in the lesions. Routine and multiple special stains by light microscopy demonstrated atherosclerotic (intimal) calcium to be deposited as fine grains, ring-shaped droplets or small needle-shaped crystals, and medial calcium as fine grains or ring-shaped droplets. The calcium deposits were frequently associated with the PAS-positive basal lamina surrounding smooth muscle cells. In the intimal lesions the calcium deposits were often associated with fine granular lipid, while this association was much less frequent in the media. Calcium in atherosclerotic intima was generally not closely associated with elastic fibers but in the media was often deposited along or near elastic fibers. By electron microscopy the atherosclerotic lesions were composed of many smooth muscle cells (with or without lipid droplets), newly formed elastic fibers, amorphous ground substance, a few collagen fibrils and many membrane-limited matrix vesicle-like structures, 100-700 nm diameter. Many similar vesicles were present between the elastic laminae of the media. With the potassium pyroantimonate technique for demonstrating calcium, reaction products were most concentrated within these matrix vesicles but were also present in mitochondria of smooth muscle cells, within extracellular mitochondria-like structures, in pericellular basal lamina-like material and loosely dispersed in the interstitial ground substance. All elastic fibers were negative for calcium by this technique. The membrane of the matrix vesicle-like structures were cytochemically positive for alkaline phosphatase and adenosine triphosphatase. These studies suggest that calcification in human atherosclerosis and media is related to smooth muscle cell degeneration and that the major initial loci for calcium deposition are matrix vesicles from degraded cells, comparable to osteogenic calcification of cartilage.

Adenosine Triphosphatases↗
PubMed1986

Calcification in atherosclerosis. II. Animal studies.

For comparison with our previous study on early calcification in human atherosclerosis, the aortas of rabbits and chickens with experimentally induced atherosclerosis were studied by gross examination, light microscopy and electron microscopy, including various cytochemical techniques. Nine male New Zealand white rabbits and nine male white leghorn chickens were fed an atherogenic diet of chow with 8% peanut oil and 2% cholesterol for one, two or three months. Six rabbits and six chickens, fed normal chow for one, two or three months, served as controls. The normal diet chickens were found to have lipid-negative spontaneous fibrous plaques in the abdominal aorta, which following atherogenic diet developed lipid deposition and increasing calcium deposition. The normal diet rabbits had no aortic lesions, but following an atherogenic diet developed highly lipid-positive foam cell intimal lesions which subsequently developed increasing amounts of smooth muscle cells and calcium. Ultrastructurally, the aortic plaques in normal diet chickens were composed of smooth muscle cells, collagen, elastic fibers, ground substance and a few small extracellular matrix vesicles bounded by a trilaminar membrane. In the atherogenic diet chickens, these vesicles increased in number as did their staining for calcium by the pyroantimonate technique. The membranes of vesicles were cytochemically positive for alkaline phosphatase and adenosine triphosphatase. Similar matrix vesicles were present in the interstitium of the media. In both intima and media, the vesicles appeared to be largely derived from degenerating smooth muscle cells. The aortas of atherogenic diet rabbits were similar to the chickens except for many more lipid-laden foam cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Purification and partial characterization of alkaline phosphatase of matrix vesicles from fetal bovine epiphyseal cartilage. Purification by monoclonal antibody affinity chromatography.

Alkaline phosphatase of matrix vesicles isolated from fetal bovine epiphyseal cartilage was purified to apparent homogeneity using monoclonal antibody affinity chromatography. The enzyme from the butanol extract of matrix vesicles bound specifically to the immobilized antibody-Sepharose in the presence of 2% Tween 20 whereas the major portion of nonspecific protein was removed by this single step. Of various agents tested, 0.6 M 2-amino-2-methyl-1-propanol, pH 10.2, was the most effective in eluting 80-100% of the enzyme initially applied. Both Tween 20 and 2-amino-2-methyl-1-propanol associated with the eluted enzyme were effectively removed by the sequential application of DEAE-cellulose and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enzyme preparation treated with sodium dodecyl sulfate and mercaptoethanol showed the presence of a dominant band (using silver staining) corresponding to a molecular weight of 81,000. This molecular weight was nearer reported values for rat liver (Ohkubo, A., Langerman, N., and Kaplan, M. M. (1974) J. Biol Chem. 249, 7174-7180) and porcine kidney (Cathala, G., Brunel, C., Chapplet-Tordo, D., and Lazdunski, M. (1975) J. Biol. Chem. 250, 6040-6045) alkaline phosphatase, than to previously reported values for chicken (Cyboron, G. W., and Wuthier, R. E. (1981) J. Biol. Chem. 256, 7262-7268) and fetal calf (Fortuna, R., Anderson, H. C., Carty, R. P., and Sajdera, S. W. (1980) Calcif. Tissue Int. 30, 217-225) cartilage matrix vesicle alkaline phosphatase. The purified alkaline phosphatase was activated by micromolar Mg2+. The amino acid composition of cartilage alkaline phosphatase was found to be similar to that previously described for porcine kidney (Wachsmuth, E. D., and Hiwada, K. (1974) Biochem. J. 141, 273-282). Double immunoprecipitation data indicated that monoclonal antibody against cartilage alkaline phosphatase cross-reacted with fetal bovine liver or kidney enzyme but failed to react with calf intestinal or rat cartilage enzyme. Thus these observations suggest that alkaline phosphatase of matrix vesicles from calcifying epiphyseal cartilage is a liver-kidney-bone isozyme.

Alkaline Phosphatase↗
PubMed1984

Isolation of a plasma membrane-enriched fraction from collagenase-suspended rachitic rat growth plate chondrocytes.

An attempt was made to concentrate plasma membranes of homogenized chondrocytes isolated by collagenase digestion of rachitic rat epiphyseal growth plate cartilage. This study reports the characterization of enzymes in the plasma membrane of isolated chondrocytes and their comparison with extracellular matrix vesicle components. The plasma membrane-enriched fractions that were obtained showed a sevenfold increase in 5'-nucleotidase and a 15-fold increase in alkaline phosphatase, both of which are regarded as plasma membrane markers. SDS-polyacrylamide gel electrophoretic profiles of proteins extracted from membrane fractions contained several major protein bands also seen in isolated matrix vesicles. These studies indicate the usefulness of concentrating plasma membrane components from isolated chondrocytes, after the chondrocytes have been enzymatically freed from investing matrix and other stromal components by collagenase.

Alkaline Phosphatase↗