rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Investigations into the mechanism of action of the toxic sesquiterpene lactones, helenalin and hymenoxon
  name:
    name part: Merrill, Jill Christine
    name part: 1955-
    role:
      role term: creator
  name:
    name part: Jones, Daniel H.
    role:
      role term: degree committee member.
  name:
    name part: Kim, Hyeong L.
    role:
      role term: degree committee member.
  name:
    name part: Plapp, Frederick W.
    role:
      role term: degree committee member.
  name:
    name part: Safe, Stephen H.
    role:
      role term: degree supervisor.
  name:
    name part: Texas A & M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  genre: Academic theses
  origin info:
    place:
      place term: xx
    date issued: 1987
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: print
    extent: xiii, 143 leaves : illustrations ; 29 cm
  abstract: Hymenoxys odorata (bitterweed) is an economically important poisonous range plant indigenous to the southwestern United States. The sesquiterpene lactone (SL), hymenoxon, has been isolated from bitterweed and demonstrated to produce signs of bitterweed toxicosis in sheep, goats, dogs, and rabbits. The precise mechanism of action is unknown, and the present series of experiments was conducted to determine the role of two structurally-related SL, hymenoxon and helenalin, on the cytochrome P-45O-dependent monooxygenases. An additional objective was to examine the role of sulfhydryl-containing compounds in determining the toxicity associated with these compounds. Both hymenoxon and helenalin elicited minimal effects on the microsomal monooxygenases in male ICR mice, and it was concluded these enzymes do not play a central role in SL toxicity. The effect of inducing hepatic glutathione (GSH) on SL toxicity was determined in mice using L-2-oxothiazolidine-4-carboxylate (OTC), an intracellular cysteine delivery system. L-2-Oxothiazolidine-4-carboxylate pretreatment resulted in significantly greater GSH values within 2 h. Levels remained elevated at 24h. The administration of either helenalin or hymenoxon resulted in significant decreases in hepatic GSH within 1.0 and 0.25 h, respectively. Pretreatment with OTC prevented the decrease in GSH subsequent to helenalin exposure and maintained, higher levels in mice exposed to hymenoxon compared with mice receiving the toxin only. Pretreatment with OTC significantly reduced the percent lethality in mice exposed to either toxin. Hepatic and renal metallothionein (MT) levels were induced by pretreating mice and Wistar rats with cadmium, zinc, cobalt, or bismuth. Cadmium and zinc induced significant increases in both hepatic and renal MT, while cobalt and bismuth induced hepatic and renal MT levels, respectively. The lethality associated with helenalin and hymenoxon exposure was significantly reduced in response to each metal pretre…
  note: "Major subject: Toxicology."
  note: Typescript (photocopy).
  note: Vita.
  note: Ph. D. Texas A & M University 1987
  note: Includes bibliographical references (leaves 129-142).
  subject:
    topic: Actinea odorata
    topic: Toxicology
  subject:
    topic: Glutathione
  subject:
    topic: Livestock poisoning plants
  subject:
    topic: Metallothionein
  subject:
    topic: Major toxicology
  identifier: http://proxy.library.tamu.edu/login
  identifier: https://hdl.handle.net/1969.1/DISSERTATIONS-26922
  identifier: http://gateway.proquest.com/openurl
  related item:
    location:
      url: http://proxy.library.tamu.edu/login
  related item:
    location:
      url: https://hdl.handle.net/1969.1/DISSERTATIONS-26922
  related item:
    location:
      url: http://gateway.proquest.com/openurl
  record info:
    record content source: TXA
    record creation date: 880713
    record change date: 20220104090750.0
    record identifier: in00000020507
    language of cataloging:
      language term: eng