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Immobilization of oxalate-degrading ...

Mellman, James Kenneth.

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Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents./
作者:	Mellman, James Kenneth.
面頁冊數:	116 p.
附註:	Adviser: Laurie Gower.
Contained By:	Dissertation Abstracts International69-01B.
標題:	Chemistry, Polymer. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3299350
ISBN:	9780549436416

Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents.
Mellman, James Kenneth.

Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents. - 116 p.

Adviser: Laurie Gower.

Thesis (Ph.D.)--University of Florida, 2007.

Ureteral stents develop calcium-bearing deposits, called encrustation, that diminish their biocompatibility due to complications, such as chronic abrasion to the lumen of the ureter wall and subsequent infection. A reduction of encrustation, namely calcium oxalate, will improve the lifetime, health care costs, and infection resistance of such devices. The purpose of this research project is to study oxalate-degrading enzymes entrapped into a coating material that will control the interface to the urinary environment for ureteral stents.

ISBN: 9780549436416Subjects--Topical Terms:

1018428
Chemistry, Polymer.

Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents.
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100 1 $a Mellman, James Kenneth. $3 1280785
245 1 0 $a Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents.
300 $a 116 p.
500 $a Adviser: Laurie Gower.
500 $a Source: Dissertation Abstracts International, Volume: 69-01, Section: B, page: 0607.
502 $a Thesis (Ph.D.)--University of Florida, 2007.
520 $a Ureteral stents develop calcium-bearing deposits, called encrustation, that diminish their biocompatibility due to complications, such as chronic abrasion to the lumen of the ureter wall and subsequent infection. A reduction of encrustation, namely calcium oxalate, will improve the lifetime, health care costs, and infection resistance of such devices. The purpose of this research project is to study oxalate-degrading enzymes entrapped into a coating material that will control the interface to the urinary environment for ureteral stents.
520 $a The coating material was a lightly crosslinked poly(2-hydroxyethyl methacrylate) (p(HEMA)) matrix in which the active enzymes were entrapped within the bulk material's free volume. The swelling of p(HEMA) films was comparable in ddH2O and urine. This hydrophilic matrix allows oxalate anions to diffuse into the bulk so that enzyme activity against oxalate can lower its local concentration, and thereby reduce the supersaturation of calcium oxalate.
520 $a Oxalate oxidase (OxO) and oxalate decarboxylase (OxDc) were the oxalate-degrading enzymes examined herein. Michaelis Menten kinetic models were applied to free and immobilized enzyme activity. A substrate inhibition model was applied to OxO. The free form of OxO had a Vmax of 1.8 +/- 0.1 muM/min-mug, a km of 1.8 +/- 0.1 mM, and a ks of 35.4 +/- 3.7 mM while the immobilized form had a Vmax of 1.2 +/- 0.2 muM/min-mug, a km of 4.1 +/- 0.6 mM, and a ks of 660 +/- 140 mM. The free form of OxDc had a Vmax of 23.5 +/- 1.4 muM/min-mug and a km of 0.5 +/- 0.1 mM while the immobilized form had a Vmax of 5.0 +/- 1.9 muM/min-mug and km of 23.2 +/- 9.1 mM.
520 $a The enzyme activity was measured to indicate viable application conditions for the coating, such as storing the films in urine over time. The maximum activity was shown at pH 4.2 to 4.5 and activity drops to be negligible by pH 7.0. Storing the enzyme at pH 6.1 exhibited a larger retained activity than storing at pH 4.2, yet storing in urine showed the highest retention. In a six moth trial period in urine, immobilized OxO lost 30% activity to 0.7 muM/min-mug, whereas the activity for immobilized OxDc fell 50% from about 5.9 to 2.9 muM/min-mug.
520 $a Coating p(HEMA) onto polyurethane ureteral stents was applied by dip coating into a monomer-based coating solution. To achieve successful coatings, the viscosity of the coating solution and adhesion to the stent were optimized through a series of experiments with glycerol and superglue to form a primer of p(HEMA). The enzymes were applied to the primer through successive layers without the use of glycerol or superglue. The enzyme activity was used to compare various processing routes, such as dip time, dip cycles, and the use of Triton X-100.
520 $a An encrustation model was established using artificial and real urine, and an antibiotic/antimycotic solution was added to prevent infection. The solutions were spiked with 0.5 mM oxalate to optimize encrustation conditions. The encrustation study was conducted up to two months in these solutions, and samples were analyzed using polarized light microscopy. Immobilized OxDc inhibited crystal growth up to two-months, although OxO developed encrustation to a similar extent of the control group. This opens the possibility of utilizing the immobilized enzyme as a therapy for degrading oxalate concentrations in urine, which can be employed as a coating on ureteral stents.
590 $a School code: 0070.
650 4 $a Chemistry, Polymer. $3 1018428
650 4 $a Engineering, Biomedical. $3 1017684
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0495
690 $a 0541
690 $a 0794
710 2 $a University of Florida. $3 718949
773 0 $t Dissertation Abstracts International $g 69-01B.
790 $a 0070
790 1 0 $a Gower, Laurie, $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3299350