Hydrogel Formation with Enzyme-Responsive Cyclic Peptides.

Self-assembling peptides (SAPs), which form hydrogels through physical cross-linking of soluble structures, are an intriguing class of materials that have been applied as tissue engineering scaffolds and drug delivery vehicles. For feasible application of these tissue mimetics via minimally invasive delivery, their bulk mechanical properties must be compatible with current delivery strategies. However, injectable SAPs which possess shear-thinning capacity, as well as the ability to reassemble after cessation of shearing can be technically challenging to generate. Many SAPs either clog the high-gauge needle/catheter at high concentration during delivery or are incapable of reassembly following delivery. In this chapter, we provide a detailed protocol for topological control of enzyme-responsive peptide-based hydrogels that enable the user to access both advantages. These materials are formulated as sterically constrained cyclic peptide progelators to temporarily disrupt self-assembly during injection-based delivery, which avoids issues with clogging of needles and catheters as well as nearby vasculature. Proteolytic cleavage by enzymes produced at the target tissue induces progelator linearization and hydrogelation. The scope of this approach is demonstrated by their ability to flow through a catheter without clogging and activated gelation upon exposure to target enzymes.

UV-responsive cyclic peptide progelator bioinks.

We describe cyclic peptide progelators which cleave in response to UV light to generate linearized peptides which then self-assemble into gel networks. Cyclic peptide progelators were synthesized, where the peptides were sterically constrained, but upon UV irradiation, predictable cleavage products were generated. Amino acid sequences and formulation conditions were altered to tune the mechanical properties of the resulting gels. Characterization of the resulting morphologies and chemistry was achieved through liquid phase and standard TEM methods, combined with matrix assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS).

RAND/UCLA Quality-of-Care Measures for Carpal Tunnel Syndrome: Tools for Assessing Quality of Care and Appropriateness of Surgery.

Claims relating to carpal tunnel syndrome (CTS) are common in workers' compensation systems. Given that the human and economic costs related to CTS are considerable, healthcare organizations must be able to offer high-quality care to people affected by this condition. The study on which this article is based is a step toward improving care for CTS. It has produced two unique tools for institutions to use, one for assessing the quality of care received by a population of patients who have or may have CTS, and the other for identifying the appropriateness of surgery for individual patients. Tools that assist in measuring quality of care are fundamental to efforts to improve healthcare quality. Tools that assess the appropriateness of surgery ensure that people who need surgery receive it and, conversely, that people are not subjected to inappropriate operations. Applied in this way, these two tools are likely to improve clinical circumstances and economic outcomes for people with CTS. Together, they can be useful to provider organizations, medical groups, medical certification boards, and other associated decisionmakers attempting to assess, monitor, and provide appropriate care for people with CTS.

Experience with an obstetric perineal clinic.

OBJECTIVE: To review the characteristics of patients attending a dedicated perineal clinic in a maternity hospital. METHODS: Case-note review of all new referrals over 2 years 1998 and 1999. RESULTS: A total of 399 women were referred with mean age of 34 years (range 18-77), parity of 1.7 (range 1-13) and duration of symptoms of 14 (range 1-156) months. A total of 213 (53%) women were assessed following a recognized third degree perineal tear, 78 (20%) because of fecal incontinence, 45 (11%) for determination of future mode of delivery following a previous perineal injury, 37 (9%) women for treatment of perineal pain and 26 (7%) for other miscellaneous complaints. A total of 83 (21%) required physiotherapy, 42 (11%) received dietetic manipulation, 29 (7%) were treated for perineal pain and 12 (3%) underwent vaginal surgery. A total of 24 (6%) women were referred for consideration of secondary anal sphincter repair and 11 (3%) for specialist gastroenterological investigation. CONCLUSIONS: The perineal clinic provides a valuable resource for investigation and treatment of postpartum perineal injury.