In vivo evaluation of the third generation biodegradable stent: a novel approach to avoiding the forgotten stent syndrome.

Purpose: Ureteral stents are prone to irritation, encrustation and infection, and they require additional procedures for removal. Furthermore, indwelling polymer stents are often forgotten with devastating consequences to the patient. We describe the degradation time, and physiological and histological responses elicited by a novel biodegradable ureteral stent in a porcine model.

Effect of mesh construction on the physicomechanical properties of bicomponent knit mesh using yarns derived from degradable copolyesters.

The use of mesh to repair abdominal wall defects has significantly increased over the past two decades owing to a perceived reduction in recurrence rates compared to primary repairs. However, the use of a mesh in vivo has introduced undesirable patient complications. As a result, there exists an unmet need for a mesh design which exhibits improved biocompatibility.

Injectable in situ forming controlled release implant composed of a poly-ether-ester-carbonate and applications in the field of chemotherapy.

Polymeric controlled delivery systems hold great promise in the field of modern medicine. Such technology has already been converted into commercially viable products in a myriad of fields. Chemotherapy is an example of such an area where constant efficacious levels of drug can greatly enhance clinical outcomes.

Development of novel biodegradable polymer scaffolds for vascular tissue engineering.

Functional connective tissues have been developed using tissue engineering approach by seeding cells on biodegradable scaffolds such as polyglycolic acid (PGA). However, a major drawback of tissue engineering approaches that utilize synthetic polymers is the persistence of polymer remnants in engineered tissues at the end of culture. Such polymer fragments may significantly degrade tissue mechanics and stimulate local inflammatory responses in vivo.

A pilot safety and tolerability study of a nonhormonal vaginal contraceptive ring.

Objective: To conduct a pilot safety and tolerability study of the Ovaprene ring (Poly-Med Inc., Clemson University, Clemson, South Carolina) as a barrier contraceptive.

Study Design: Open-label, single-arm, observational study in a convenient sample of volunteers.

Next generation biodegradable ureteral stent in a yucatan pig model.

Purpose: Ureteral stents are commonly used to facilitate kidney drainage but they may produce significant stent symptoms and morbidity, and require a secondary procedure for removal. Previous biodegradable stents showed bio-incompatibility or inconsistent degradation, requiring extra procedures to remove undegraded stent fragments. We previously reported a first generation biodegradable stent composed of suture-like material that required placement through the lumen of a sheath and degraded by 10 weeks.

Investigation of a novel degradable ureteral stent in a porcine model.

Purpose: Ureteral stents often result in patient morbidity and the potential for a forgotten stent. When the suture tether is detached, a secondary procedure is required for removal. Previous attempts at developing biodegradable ureteral stents have been unsuccessful since those stents were not biocompatible or they failed to degrade in timely fashion.

Direct correlation between adsorption-induced changes in protein structure and platelet adhesion.

It is widely recognized that adsorbed proteins on biomaterial surfaces tend to initiate thrombus formation, although the specific mechanisms involved are still not well understood. In attempts to decrease the conformational change of adsorbed proteins, surface treatments that reduce surface hydrophobicity have been considered, such as the sulfonation of low-density polyethylene and isotactic polypropylene. The objectives of this present research were to study how changes in surface chemistry influence the degree of conformational change of adsorbing proteins and to investigate the correlation between the change in adsorbed protein structure and platelet response.

Absorbable microparticulate cation exchanger for immunotherapeutic delivery.

An absorbable microparticulate cation exchanger was synthesized as a versatile carrier for biologically active proteins. In this work, acid-terminated polyglycolide (or polyglycolic acid) microparticulates (PG-MP) were surface modified for either sustained release of cytokines or as a platform for immunomodulation. The intended goal was to achieve in situ recruitment/maturation of dendritic cells and activation of T cells for tumor immunotherapy.

Development of novel substrates for tumor immunotherapy.

Acid-terminated polyglycolide microparticles (PG-MP) were prepared as a versatile substrate that could be surface-modified for either immobilization of anti-cd3 and anti-cd28 mAb to activate T cells or sustained release of granulocyte-macrophage colony stimulating factor (GM-CSF) for dendritic cell (DC) recruitment and maturation. PG-MP were prepared with a volume-weighted mean diameter of 56 or 57 microm. Accessible carboxylic acid group concentration was determined by potentiometric titration to be 0.

In vitro evaluation of phosphonylated low-density polyethylene for vascular applications.

The use of catheters for vascular applications is often complicated by the development of friction between the catheter material and the vessel wall, which leads to endothelial cell removal and intimal lesions. Phosphonylation, a chemical surface treatment, has been proposed as a means of increasing the hydrophilicity of low-density polyethylene (LDPE), a commonly used catheter material, in efforts to impart lubricity to the material and reduce vascular tissue damage. In an in vitro tribological study, phosphonylated LDPE produced a lower coefficient of friction and allowed greater retention of endothelial cells on vessels as compared to untreated LDPE when the materials were reciprocated against normal porcine aorta.