H Birkedal-Hansen

University of Alabama at Birmingham, Birmingham, AL, United States

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Publications (22)39.23 Total impact

  • H Birkedal-Hansen, W T Butler, R E Taylor
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    ABSTRACT: Cyanogen bromide (CNBr) peptides were prepared of the insoluble collagen of bovine dental cementum. Following chromatographic separation, the peptides were identified by their amino-acid composition. Type I collagen ([alpha1(I)]2alpha2) accounted for more than 90% of the organic matrix, while Type III collagen ([alpha1(III)]3) was present at a level of approximately 5%. Amino-acid analyses revealed that the CNBr peptides from alpha1(I) and alpha2 chains of cementum closely resembled the corresponding peptides from calf skin. The only systematic difference was a higher level of hydroxylation of prolyl and lysyl residues of the cementum peptides.
    Calcified Tissue Research 06/1977; 23(1):39-44.
  • Henning Birkedal-Hansen, William T. Butler, Robert E. Taylor
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    ABSTRACT: Cyanogen bromide (CNBr) peptides were prepared of the insoluble collagen of bovine dental cementum. Following chromatographic separation, the peptides were identified by their amino-acid composition. Type I collagen ([1(I)]22) accounted for more than 90% of the organic matrix, while Type III collagen ([1(III)]3) was present at a level of approximately 5%. Amino-acid analyses revealed that the CNBr peptides from 1(I) and 2 chains of cementum closely resembled the corresponding peptides from calf skin. The only systematic difference was a higher level of hydroxylation of prolyl and lysyl residues of the cementum peptides.
    Calcified Tissue International 01/1977; 23(1):39-44. · 2.75 Impact Factor
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: Proteases capable of activating procollagenase from gingiva and from fibroblast and macrophage monolayer cultures were harvested from homogenates of canine tumor mast cells. The mast cell proteases lysed casein and Azocoll but not native collagen. In low salt concentrations the enzymes existed at high molecular weight complexes, which were dissociated by increasing the salt concentration above 1.0 M (NaCl, KCl). Gel filtration in 1.4 M KCl separated the protease activity into three peaks, all of which activated procollagenase. Two of the enzymes showed substrate specificities (hydrolysis of p-tosyl-L-arginine methyl ester and benzoyl-tyrosine ethyl ester) and reactive center reactivities similar to pancreatic trypsin and chymotrypsin. Based on gel filtration, apparent molecular weights of 160 000 (p-tosyl-L-arginine methyl ester esterase), 90 000 (main procollagenase activator) and 36 000 benzoyl-tyrosine ethyl ester esterase) were determined. Activation of procollagenase resulted in a 18-20 000 decrease of the molecular weight. The activation was directly related to the amount of activator added within certain limits. Further addition of activator resulted in proteolytic inactivation of collagenase.
    Biochimica et Biophysica Acta 07/1976; 438(1):273-86. · 4.66 Impact Factor
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    H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: An inactive collagenase was harvested from both serum-free and serum-supplemented fibroblast monolayer cultures in periods of active collagen synthesis. The latent collagenase did not hydrolyze collagen and did not bind the potent collagenase inhibitor alpha2-macroglobulin. Activation with trypsin imparted to the enzyme the ability to hydrolyze collagen at neutral pH in a typical manner and to form an inhibited complex with alpha2-macroglobulin. The molecular weights, determined by calibrated gel filtration, were 78,000 and 60,000 for the latent and active enzymes, respectively. The data indicate that collagenase is released from the cells in inactive form, as a zymogen.
    Journal of Biological Chemistry 06/1976; 251(10):3162-8. · 4.65 Impact Factor
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: 1. Collagenase (EC 3.4.24.3) is released from bovine gingival explants in vitro as a zymogen. The zymogen does not hydrolyze collagen and does not form a complex with alpha2-macroglobulin (alpha2-M). It elutes in gel filtration with an apparent molecular weight of approx. 80 000. 2. Incubation of the zymogen with trypsin results in a 15 000-20 000 dalton decrease in molecular weight and imparts to the enzyme the ability to hydrolyze collagen and to form a complex with alppha2-M. 3. The zymogen can be completely separated from the active enzyme to alpha2-M. Likewise, the zymogen can be harvested from cultures supplemented with serum.
    Biochimica et Biophysica Acta 04/1976; 429(1):229-38. · 4.66 Impact Factor
  • H Birkedal-Hansen, R E Taylor, H M Fullmer
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    ABSTRACT: Collagenase harvested in vitro from rabbit alveolar macrophages eluted in gel chromatography corresponding to apparent molecular weights of 45 000, 85 000, and 165 000. Reversible changes from one molecular weight to another in low salt concentration and predominance of the 45 000 species in salt concentrations above 1.0 M (NaCl, KCl) suggest that the higher molecular weights represent polymeric forms of collagenase.
    Biochimica et Biophysica Acta 03/1976; 420(2):428-32. · 4.66 Impact Factor
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: The site of collagenase production in explants of bovine gingiva was located by tissue culture techniques. Collagenase was released from the juxta-epithelial connective tissue, but not from the epithelium. Addition of serum to the explants resulted in outgrowth of a single cell type, which was identified as a fibroblast on the basis of culture morphology and light and electron-microscopic characteristics. The fibroblasts elaborated a collagenase that was indistinguishable from the enzyme harvested from whole bovine gingival explants. The enzymes, both of which were released in latent form, had the same molecular size and had common antigenic sites.
    Archives of Oral Biology 02/1976; 21(5):297-305. · 1.55 Impact Factor
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: Rabbit alveolar macrophages, harvested by lavage, were cultured for 4 days in Dulbecco's modified Eagle medium and the culture fluids assayed for collagenase activity. Stimulation of the macrophages in vivo by injection of Freund's complete adjuvant or vitro by addition of a soluble bovine lymphocyte extract led to a 5–10 fold increase in the production of collagenase. The major part of the collagenase present in the culture fluids was latent and could be activated by brief exposure to trypsin.
    Archives of Oral Biology 02/1976; 21(1):21-5. · 1.55 Impact Factor
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    W T Butler, H Birkedal-Hansen, W F Beegle, R E Taylor, E Chung
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    ABSTRACT: Insoluble collagen was prepared from bovine periodontal ligament. Isolation and characterization of CNBr peptides originating from the alpha1(I), alpha2, and alpha1(III) chains showed that the tissue contained both type I and type III collagens. Further evidence for the presence of type III collagen was obtained by the isolation of alpha1(III) chains from pepsin-treated ligament collagen, with properties similar to those of human alpha1(III) chains. Estimates based on the amounts of certain CNBr peptides indicated that about one-fifth of the collagen of periodontal ligament is type III, the remainder being type I collagen.
    Journal of Biological Chemistry 01/1976; 250(23):8907-12. · 4.65 Impact Factor
  • C M Cobb, H Birkedal-Hansen, F R Denys
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    ABSTRACT: Mast cells obtained from a canine mastocytoma were maintained in cell culture for a period of 11 weeks. Samples of these cells were harvested for electron microscopic examination after 9 weeks in vitro. Although the overall morphologic appearance was sufficient to allow their identification as mast cells, the tumor cells differed in several respects from descriptions of normal tissue mast cells. In contrast to normal tissue mast cells, the tumor cells exhibited peripheral accumulations of microfilaments, randomly dispersed microtubules, and small clusters of smooth endoplasmic reticulum. The tumor mast cells also presented three different granule types: spherical granules with an amorphous and electron dense matrix; irregularly shaped granules possessing a limiting external membrane and an internal matrix containing laminated and/or coiled structures; and granules containing loosely coiled, unorganized membrane structures similar in appearance to myelin whorls. The canine mastocytoma is an excellent source of mast cells as they can be obtained in large numbers without contamination by extraneous cell types and the cells can be maintained in vitro for extended periods of time.
    Journal of oral pathology 12/1975; 4(5):244-56.
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: Latent collagenase from primary cultures of bovine gingiva was activated by brief exposure to trypsin and to a lesser extent by thiocyanate. The data suggest that activation by trypsin involves two distinct mechanisms: release of collagenase activity from high molecular weight inhibitor complexes and activation of latent collagenase (possibly a procollagenase) of approximately the same molecular size as active collagenase. Inhibition experiments confirmed that collagenase activity can be recovered from inactive inhibitor complexes, formed by the addition of whole serum or α2-macroglobulin alone, after dialysis against thiocyanate or by brief exposure to trypsin.
    Archives of Oral Biology 11/1975; 20(10):681-5. · 1.55 Impact Factor
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: Latent collagenase, subject to activation by trypsin, was found in culture fluids of cells and tissues from several mammalian sources. The activation requires exposure to enzymatically active trypsin and cannot be achieved by inhibited or by heat-inactivated trypsin.
    Scandinavian journal of dental research 10/1975; 83(5):302-5.
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    ABSTRACT: abstract— Latent collagenase, subject to activation by trypsin, was found in culture fluids of cells and tissues from several mammalian sources. The activation requires exposure to enzymatically active trypsin and cannot be achieved by inhibited or by heat-inactivated trypsin.
    European Journal Of Oral Sciences 09/1975; 83(5):302 - 305. · 1.42 Impact Factor
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    H Birkedal-Hansen
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    ABSTRACT: The diffusion coefficient for diffusion of HCl in the organic matrix of elephant's ivory dentine was determined for various concentrations by measuring the fractional uptake of H36Cl in decalcified, cylindrical specimens with concealed end surfaces using a Geiger-Müller counter. Values for the effective diffusion coefficient for sorption of HCl were greatly dependent on concentration (6.1 x l0–6 cm2/sec for 1.0 N HCl to 0.l8-10–6 cm2/sec for 0.01 N). On the basis of an approximate kinetic model the diffusion coefficient for simple diffusion was estimated (9-12 x 10–6 cm2/sec). The effect of stirring on the rate of sorption was negligible.
    Journal of Histochemistry and Cytochemistry 07/1974; 22(6):428-33. · 2.26 Impact Factor
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    H Birkedal-Hansen
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    ABSTRACT: The rate of progression of the demineralization front during acid demineralization is investigated for standardized elephant's ivory dentine specimens. A theoretical model for the penetration based upon a combined diffusion with reaction process is set up. It is demonstrated that the results are in accordance with the proposed model. For specimens of certain geometrical shapes (semi-infinite or plane sheet) the distance penetrated by the front is directly proportional to the square root of the time.
    Journal of Histochemistry and Cytochemistry 07/1974; 22(6):434-41. · 2.26 Impact Factor
  • H Birkedal-Hansen, W T Butler, R E Taylor
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    ABSTRACT: A method for the isolation of dental cementum is described. Amino acid analysis of the insoluble matrix of cementum, and chromatography of the CNBr peptides derived therefrom, strongly suggest that this material is mainly collagen with the chain composition α1[(I)]2α2.
    Calcified Tissue Research 02/1974; 15(4):325-8.
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: A collagenase active against native collagen was found in culture fluids of bovine gingiva. The enzyme first appeared in the culture fluid after 1-2 days and could be harvested thereafter for at least 30 days. The collagenase attacked collagen fibrils and cleaved collagen in solution, resulting in reaction products 1/4 and 3/4 of the length of the original molecule. The enzyme was inhibited by serum, by EDTA and by cysteine. The molecular weight was estimated by gel filtration to be 63,000 daltons.
    Journal of oral pathology 02/1974; 3(5):232-8.
  • H Birkedal-Hansen
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    ABSTRACT: abstract— The effect of fixation with eight different fixatives on histochemical demonstration of carbohydrates in EDTA demineralized, paraffin sections of the rat jaw was investigated. The degree of preservation of carbohydrates was assessed by staining with PAS, toluidine blue 0, alcian blue and aldehyde fuchsin. Morphologic and cytologic preservation was evaluated from hematoxylin-eosin and toluidine blue 0 stained sections. Best results were obtained with cetylpyridinium chloride-formalin, but also formol-calcium and 10% neutral buffered acrolein gave good results, slightly better than lead nitrate-formalin. Among aldehydic fixatives, only acetic acid-alcohol-formalin gave inferior results. Non-aldehydic fixatives, aminoacridine-ethanol, lead subacetate-alcohol-acetic acid and Newcomer's isopropanol fixative were useless in combination with EDTA demineralization and paraffin embedding.
    Scandinavian journal of dental research 02/1974; 82(2):99-112.
  • H Birkedal-Hansen, C M Cobb, R E Taylor, H M Fullmer
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    ABSTRACT: Collagenases derived from bovine and human gingiva are inhibited effectively by serum. In bovine and human serum fractionated by gel chromatography, alpha2-macroglobulin is the only significant inhibitor of gingival collagenase. alpha11-Antitrypsin inhibited collagenase only in very high concentration and was several hundred-fold less effective than alpha2-macroglobulin. Inhibition of gingival collagenase with alpha2-macroglobulin is accompanied by the formation of an enzyme-inhibitor complex, which has retained no collagenolytic activity.
    Journal of oral pathology 02/1974; 3(6):284-90.
  • H Birkedal-Hansen
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    ABSTRACT: abstract— The distribution of carbohydrates in paraffin sections of jaws from young rats was investigated with various histochemical methods (PAS, alcian blue, aldehyde fuchsin, and metachromatic staining) in combination with blocking, unblocking and extraction experiments. Glycoproteins and glycosaminoglycans, predominantly chondroitin sulfates, were found abundantly in teeth and surrounding structures. The results are discussed and correlated to recent biochemical findings.
    Scandinavian journal of dental research 02/1974; 82(2):113-27.

Publication Stats

231 Citations
39.23 Total Impact Points

Institutions

  • 1974–1977
    • University of Alabama at Birmingham
      • School of Dentistry
      Birmingham, AL, United States
  • 1974–1976
    • University of Alabama
      Tuscaloosa, Alabama, United States
  • 1973–1974
    • Royal Australasian College of Dental Surgeons
      Денмарк, Western Australia, Australia