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dc.contributor.authorCsukas, Stephen
dc.date.accessioned2019-05-02T01:10:29Z
dc.date.available2019-05-02T01:10:29Z
dc.date.issued1987-06
dc.identifier.urien
dc.identifier.urihttp://hdl.handle.net/10675.2/622298
dc.description.abstractInvestigation of -'Rabbit Ey.e. Anterior Segment_ Reducing Capacity: Interplay Between Hydro·gen Peroxide, _Ascorbic Acid. and Reduc~ive Enzyme Systems (Under the Direction of KEITH- GREEN, Ph.D., D.Sc.) The experiments perfo~ed in this' body of work lay the. foundation. •. . for· describing the- sequelae_ .of an in vivo modification in. the reducing · ca.pacity. of the normal rabbit ocular ntilieu following the intro.ductiO? of an oxidative insult into the anterio·r- chamber .. of th~ rabbit eye. The· concentration of intracame:rally ·injected hydrogeri: peroxi-de (HP),. strong en~ugh to c·ause oxidative d~mage, ·and y~t not elicit a white cell response was first determined. The morp~ological and physiological responses to this. ·dose of HP were studied_ ·and described.~ · . - . Age related differences in response· to HP inj e_ction were manifested - ' - . between young and adult rabl:?its •.. Catala-se levels· were measured i~- i:r:i.s ~ ·. ciliary body, _cor~eal endothel-fum, liver ·and- lung. tfssues. Catalase · levels· ·were· demonstrated· to decrease with maturation. Values for ascorbate and HP in· aqueous-humor, an4 ascorbate ·in pla~ma were determined. ·.Ascorbate and HP levels. correlated in young and :adult anitnals •. -Corneal endothelia_l glutathione ·-redox state· ~as .. shifted . toward ·the heavily oxid:i.ze_d $tate ·.a.ftfiar_ intracameral hydrogen· peroxide . . . injectio? confirming 'that the· capacity for HP reduction of the_ . glutathione redox system wit~in the endothelium was being overwhelmed by-· the bolus. HP injection. ·Catalase levels were chemically inhibited by intravenous injection ·of· 3-aminotriazole (3AT) into adult ·animals to mimic the ·condition of a X diminished .ocular-· r~ducing _power. The dose_ response relationship was determined between the dose· ;of 3AT ·and the resultant catalase activ:i,tie~. : ... . . in ocular tissues. · The t~ Jo.r loss of HP from the aqueous humor was determined under control and.catalase inhibited-conditions,· and . ' demonstrated. a trend of fnGreasing length concurrent to increased catalase inhibition. The relationship between 'total ocular· reducing· power and.the t~ of,HP dissipation was determined by combining data ·from . . . . - the two experiments. Ocular. tissues exposed· to intracamerally injected I HPwhile· under 3AT inhibition of catalase activity demonstrated an exacerbated response compared with non-3AT treated· t:j_ssues •. These ' 'results suggest. 'an underlyin'g· r:elationship _between ~otal ocular reducing ' power and exte~t.of damag~ arising from contact with oxidants. 3AT was given orally ~o adult rabbits to determine _the .effects of long term-inhibition of catalase levels. These.animals were not . ' challenged. with in.tracamerally intro<iuced HP but rather were studied· to . ' ·determin~ the effects of 3AT on .endogenous.HP levels. Decreases were noted in levels· of qcular· ascorbate.· and HP but not in levels of plasma ascorbate. Concurrent morphological changes were also rioted in the- .posterior portion of the rabbit lens. These inclqded bleb bing and · · macuolization of· lens fibers~. The findings of thes·e studies witk rabbits suggest that: 1) . ' . catalase-activity decreases with_ maturation: in rabbits; 2) decreases in catalase activity can beachieved using 3AT; 3) challenging oculaJ; tissues with exogenous HP can expose the underlying relationship .. between .ocular reducing power _and· levels of oxidants under normal· conditions and during inflammatory .condi:tions; 4) und·er conditions of greater than· 50% inhibition of catalase levels, other reductive .systems such. as the glutathione redox cycle play. an increasingly important role; and 5) when catalase levels are inhibited for long periods of time without concurrent exogenous HP challenge, major morphological and chemical changes occur in the aqueous humor.en_US
dc.rightsCopyright protected. Unauthorized reproduction or use beyond the exceptions granted by the Fair Use clause of U.S. Copyright law may violate federal law.en_US
dc.subjectAnimalsen_US
dc.subjectRabbiten_US
dc.subjectBlistersen_US
dc.subjectCatalaseen_US
dc.subjectAqueous Humoren_US
dc.titleInvestigation of Rabbit Eye Anterior Segment Reducing Capacity: Interplay Between Hydrogen peroxide, Ascorbic Acid and Reductive Enzyme Systemsen_US
dc.typeDissertationen_US
dc.contributor.departmentDepartment of Endocrinologyen_US
dc.description.advisorN/Aen_US
dc.description.degreeDoctor of Philosophyen_US
dc.description.committeeN/Aen_US
refterms.dateFOA2019-05-02T01:10:30Z


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