Degradation of Poly(ε-caprolactone) Resorbable Multifilament Yarn under Physiological Conditions.

Poly(ε-caprolactone) (PCL) is a hydrophobic, resorbable aliphatic polymer recognized for its low tenacity and extensive elongation at break, making it a popular choice for fabricating biodegradable tissue engineering scaffolds. PCL's slow degradation rate typically results in a complete resorption period of 2 to 3 years. While numerous studies have examined the degradation of PCL in various forms such as films and webs, no study to date has investigated its physiological degradation in multifilament yarn form. In this study, we subjected PCL multifilament yarn samples to physiological conditions in phosphate-buffered saline (PBS) maintained at a consistent temperature of 37 ± 2 °C and agitated at 45 rpm for a period of 32 weeks. We retrieved samples at five different intervals to analyze the degradation profile of the multifilament yarn. This allowed us to estimate the complete resorption time and rate under these in vitro conditions. Over the 32-week period, the multifilament yarn's mass decreased by 4.8%, its elongation at break declined by 42%, the tenacity dropped by 40%, and the peak load at break fell by 46.5%. Based on these findings, we predict that a scaffold structure incorporating PCL multifilament yarn would undergo complete resorption in approximately 14 months under physiological conditions, such as in PBS solution at a pH of approximately 7 and a temperature of 37 °C.

Incidence and Recovery of Vocal Fold Immobility Following Pediatric Cardiac Operations.

BACKGROUND: Loss of laryngeal function after congenital cardiac surgery causes morbidity and prolongs hospitalization. Early diagnosis of vocal fold immobility (VFI) and referral to pediatric otolaryngology (pOTO) aids in laryngeal rehabilitation. Understanding the incidence and recovery rates of VFI enables counseling for families of infants undergoing high-risk surgery. METHODS: A retrospective chart review from November 2014 to July 2019 of infants postcardiac surgery where the aortic arch or surrounding structures were manipulated and were screened via flexible fiberoptic laryngoscopy (FFL) at a single institution was performed. Patients were divided into five surgical categories: Norwood procedure, aortic arch augmentation via median sternotomy, arterial switch operation, coarctation repair via lateral thoracotomy, and cardiac surgeries including ligation of a patent ductus arteriosus (PDA). Patients undergoing isolated PDA ligation were excluded. RESULTS: One hundred ninety-nine qualifying operations occurred during this period; 28 patients did not undergo FFL before discharge and were excluded from the analysis. Immediately following cardiac surgery, 34% (58 of 171 patients) had VFI. Follow-up was completed by 38 of 58 patients with VFI. Complete recovery was demonstrated in 63% (24 of 38) of patients by 6 months and in 86% (33 of 38) within 18 months. The highest risk occurred with the Norwood procedure and arch augmentation via median sternotomy. CONCLUSIONS: Infants undergoing surgery involving the aortic arch and surrounding structures have high rates of VFI. Follow-up by pOTO is recommended to optimize laryngeal rehabilitation. Most patients have spontaneous recovery within 18 months of cardiac surgery.

Poly(ε-Caprolactone) Resorbable Auxetic Designed Knitted Scaffolds for Craniofacial Skeletal Muscle Regeneration.

Craniofacial microsomia is a congenital deformity caused by asymmetric development of the skull (cranium) and face before birth. Current treatments include corrective surgery and replacement of the deformed structure using autograft tissue, which results in donor site morbidity. An alternative therapy can be achieved by developing a resorbable scaffold for skeletal muscle regeneration which will help restore the symmetry and function of the facial muscles and reduce donor site morbidity. Two resorbable weft knitted scaffolds were fabricated using poly(ε-caprolactone) multifilament yarns with unique auxetic design structures possessing negative Poisson's ratio (NPR). These scaffolds exhibit their NPR elasticity through an increase in total volume as well as no lateral narrowing when stretched longitudinally, which can provide orientated mechanical supports to the cell growth of skeletal muscle regeneration. These scaffolds were evaluated for the required physical properties, mechanical performance and biocompatibility by culturing them with neonatal human dermal fibroblasts so as to determine their cell metabolic activity, cell attachment and proliferation. This study can facilitate the understanding and engineering of textile-based scaffolds for tissues/organs. The work also paves a pathway to emerge the NPR textiles into tissue engineering, which has an extensive potential for biomedical end-uses.

The implications of the Medicare Modernization Act for dual eligibles.

Medicare beneficiaries with incomes at or near the poverty level are also eligible for benefits provided by state Medicaid programs. The Medicare Modernization Act of 2003 details special provisions for these "dually eligible" individuals compared with other Medicare beneficiaries. Issues related to enrollment, benefits, and patient compliance are discussed, as well as challenges physicians face in caring for this vulnerable population.