Now showing items 1-20 of 1022

    • The Mechanism of Diacyl Peroxide Decomposition 

      Linhardt, Robert J. (Johns Hopkins University, 1979)
      Various substituted 4-X-diphenylacetyl Y-benzoyl peroxides have been prepared and characterized in situ by low temperature NMR and IR spectroscopy. These peroxides decompose in non-nucleophilic solvents below -20°C, with ...
    • Mechanism of Decomposition for Diacyl Peroxides and Related Carboxy Inversion Compounds in Aqueous Acetone 

      Linhardt, Robert J.; Murr, B.L. (Elsevier, 1979)
      The recent report of CINDP during the decomposition of t-butylacetyl m-chlorobenzoyl peroxide, which was interpreted as arising from polarized, rearranged ion pair intermediates, [1] prompts us to report the behavior of ...
    • Blood Deheparinization Using Immobilized Microbial Heparinase 

      Linhardt, Robert J.; Langer, R.; Cooney, C.L.; Galliher, P.M.; Flanagan, M.M.; Hoffberg, S.M. (Canadian Society for Chemical Engineering, 1981)
      Extracorporeal medical machines (e.g., artificial kidney, pump-oxygenator) perfused with blood have been an effective part of the therapeutic armamentarium for many years. These devices all rely on systemic heparinization ...
    • Heparinase Production by Flavobacterium heparinum 

      Galliher, P.M.; Cooney, C.L.; Langer R.; Linhardt, Robert J. (1981)
      Heparinase production by Flavobacterium heparinum in complex protein digest medium, with heparin employed as the inducer, has been studied and improved. The maximum productivity of heparinase has been increased 156-fold ...
    • Differential Anticoagulant Activity of Heparin Fragments Prepared Using Microbial Heparinase 

      Linhardt, Robert J.; Grant, A.; Cooney, C.L.; Langer, R. (Elsevier, 1982)
      Heparin of an average molecular weight of 13,000 with known polydispersity was degraded using microbial heparinase. The kinetics of this degradation were followed by four assays which measured the anticoagulant activity ...
    • A System for Heparin Removal 

      Langer, R.; Linhardt, Robert J.; Klein, M.; Galliher, P.M.; Cooney C.L.; Flanagan, M.M. (1982)
      Extracorporeal medical machines rely on systemic heparinization to improve blood compatibility. However, heparin can lead to serious complications such as hemorrhaging. We propose a new approach to control heparin levels ...
    • Mechanism of Diacyl Peroxide Decomposition 

      Linhardt, Robert J.; Murr, B.L.; Montgomery, E.; Osby J.; Sherbine, J. (1982)
      The presence of ion-pair intermediates in diacyl peroxide decomposition has been established. Various substituted (4-X·pOOiyl)phenylaoetyl Y·benzoyl peroxides and three corresponding 4·X-bemhydryl-4·nitrobenzolc carbonic ...
    • The Regulation of Heparinase Production in Flavobacterium heparinum 

      Galliher, P.M.; Linhardt, Robert J.; Conway, L.J.; Langer, R.; Cooney, C.L. (1982)
      The effect of various carbon, nitrogen and sulfur sources on the production of heparinase by Flavobacterium heparinum in defined medium in the presence and absence of heparin as the inducer has been studied. Carbon catabolite ...
    • In Vivo Activity of Microbial Heparinase 

      Langer, R.; Linhardt, Robert J.; Larsen, A.K.; Cooney, C.L.; Tapper, D.; Klein, M. (1982)
      Heparin, prepared from mammalian intestinal mucosa, is the most widely used anticoagulant. It has been estimated, however, that the use of heparin leads to complications such as bleeding 8-33% of the time1. Of all prescription ...
    • Immobilized Heparinase: Productions, Purification, and Application In Extracorporeal Therapy 

      Langer, R.; Linhardt, Robert J.; Cooney, C.L.; Tapper, D.; Klein, M.D. (1982-01-01)
      There are nearly 20,000,000 perfusions involving extracorporeal medical machines performed each year (1,2). The artificial kidney is employed several times weekly by over 100,000 persons each year (1). Open-heart operations ...
    • An Enzymatic System for Removing Heparin in Extracorporeal Therapy 

      Langer, Robert; Linhardt, Robert J.; Hoffberg, Steven; Larsen, Annette K.; Cooney, Charles L.; Tapper, David; Klein, Michael (1982-01-01)
      The need to fully heparinize patients undergoing extracorporeal therapy often leads to hemorrhagic complications. To enable heparinization of only the extracorporeal circuit, a blood filter containing immobilized heparinase ...
    • Mode of Action of Heparin Lyase On Heparin 

      Lindhardt, Robert J.; Fitzgerald, Gerald L.; Cooney, Charles L.; Langer, Robert (1982-04-03)
      Heparinase (heparin lyase, EC 4.2.2.7) prepared from Flavobacterium heparinum was used to digest heparin. The products of digestion were examined with a viscosometric assay at various stages of the reaction to measure their ...
    • A Colorimetric Assay for Chemical Heparin in Plasma 

      Klein, Michael D.; Drongowski, Robert A.; Linhardt, Robert J.; Langer, Robert S. (1982-07-15)
      A simple, rapid colorimetric assay for plasma heparin is presented. The assay employs the metachromasia of azure A when heparin is added. It is useful for 0 to 10 units/ml and does not depend on heparin's anticoagulant ...
    • Heparinase: In Vivo Activity and Immunogenicity in Rabbits 

      Klein, M.D.; Drongowski, R.A.; Linhardt, Robert J.; Cooney, C.L.; Langer, R.S. (1983)
      Anticoagulation with heparin is required during extracorporeal circulation for hemodialysis and cardiopulmonary bypass as well as during vascular surgery. Reversal of anticoagulation with protamine may be associated with ...
    • Bioerodible Polyanhydrides For Controlled Drug Delivery 

      Rosen, H.; Chang, J.; Wenik, G.; Linhardt, Robert J.; Langer, R. (1983)
      Initial in vitro and in vivo (rat) studies using a poly(anhydride), poly[bis(p-carboxyphenoxy)methane], as a bioerodible matrix for controlled drug delivery are described. Drug delivery matrices fabricated from this material ...
    • Bioerodable Polyanhydrides for Controlled Drug Delivery 

      Linhardt, Robert J.; Rosen, H.B.; Langer, R. (1983)
      Initial in vitro and in vivo (rat) studies using a poly(anhydride), poly[bis(p-carboxyphenoxy)methane], as a bioerodible matrix for controlled drug delivery are described. Drug delivery matrices fabricated from this material ...
    • Angiogenesis Inhibition and Tumor Regression Caused by Heparin or a Heparin Fragment in the Presence of Cortisone 

      Folkman, Judah; Langer, Robert; Linhardt, Robert J.; Haudenschild, Christian; Taylor, Stephanie (1983-01-01)
      Heparin or a heparin fragment administered with cortisone inhibited angiogenesis, caused regression of large tumor masses, and prevented metastases. Oral administration of heparin resulted in the release of non-anticoagulant ...
    • Polymer Based Drug Delivery: Magnetic Modulation and Bioerodible Systems 

      Edelmen, E.; Linhardt, Robert J.; Bobeck, H.; Kost, J.; Rosen, H.B.; Langer, R. (1984)
      Polymer based drug, delivery systems have been considered for many applications to supplement standard means of medical therapeutics. Currently nitroglycerin, scopolamine, progesterone, and pilocarpine [1] are being ...
    • The Effect of Extracorporeal Enzymatic Deheparinization on the Formed Blood Components 

      Larsen, Annette K.; Linhardt, Robert J.; Tapper, David; Klein, Michael; Langer, Robert (1984-01-01)
      A stirred blood filter containing an immobilized enzyme, heparinase, has been used to neutralize heparin's anticoagulant activity at the outflow of an extracorporeal circuit in dogs. The hematocrit and red blood cell count ...
    • An Immobilized Microbial Heparinase for Blood Deheparinization 

      Linhardt, R. J.; Cooney, C. L.; Tapper, D.; Zannetos, C. A.; Larsen, A. K.; Langer, R. (1984-02-01)
      A new medical application of an immobilized microbial enzyme is described. Extracorporeal devices require systemic heparin administration to prevent thrombus formation; however, the use of heparin often leads to serious ...