A novel self-gripping long-term resorbable mesh providing temporary support for open primary ventral and incisional hernia.

A novel synthetic fully long-term resorbable self-gripping mesh has been recently developed to reinforce soft tissue where weakness exists during ventral hernia repair open procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology, providing grips on one side of the mesh. A new poly-L-lactide, poly-trimethylene copolymer was developed to provide the required features for mechanical support during at least 20 weeks covering the critical healing period, including resistance to fatigue under cyclic loading conditions, as it occurs in patients. The yarns and mesh initial physical and biomechanical properties were characterized. Then, the mesh mechanical strength was evaluated over time. The mechanical properties of the proposed mesh were found to be above the generally recognized threshold value to mechanically support the repair site of a hernia over a 20-week period during in-vitro cyclic loading test. The mesh performance was evaluated in vivo using a published preclinical porcine model of hernia repair at 4-, 12- and 20-weeks post implantation. The burst strength of the hernia repair sites reinforced with the new mesh were higher at 4 & 12 weeks and comparable at 20 weeks to the one of the native abdominal walls. At all time points, the mesh was well tolerated with moderate inflammation and was fast integrated in the abdominal wall at 4 weeks. Particularly, the grips were nicely engulfed in the newly formed connective tissue. They must facilitate the anchoring of the mesh by their extension from the mesh and their mushroom shape. The preclinical data of the self-gripping resorbable mesh suggests that it has all the favorable characteristics for future clinical use during ventral hernia repair open procedures.

FTIR microscopy contribution for comprehension of degradation mechanisms in PLA-based implantable medical devices.

The integration and evolution of implantable medical devices made of bioresorbable polymers and used for temporary biomedical applications are crucial criteria in the success of a therapy and means of follow-up after implantation are needed. The objective of this work is to develop and evaluate a method based on microscopic Fourier Transform InfraRed spectroscopy (FTIR) mappings to monitor the degradation of such polymers on tissue explant sections, after implantation. This technique provided information on their location and on both their composition and crystallinity, which is directly linked to their state of degradation induced predominantly by chain scissions. An in vitro study was first performed on poly(L-lactic acid) (PLLA) meshes to validate the procedure and the assumption that changes observed on FTIR spectra are indeed a consequence of degradation. Then, mappings of in vivo degraded PLLA meshes were realized to follow up their degradation and to better visualize their degradation mechanisms. This work further warrants its translation to medical implants made of copolymers of lactic acid and to other polyesters.

Randomized Trial of Interpersonal Psychotherapy and Cognitive Behavioral Therapy for Major Depressive Disorder in a Community-Based Psychiatric Outpatient Clinic.

BACKGROUND: Interpersonal psychotherapy (IPT) and cognitive behavioral therapy (CBT) are both evidence-based treatments for major depressive disorder (MDD). Several head-to-head comparisons have been made, mostly in the United States. In this trial, we compared the two treatments in a small-town outpatient psychiatric clinic in Sweden. The patients had failed previous primary care treatment and had extensive Axis-II comorbidity. Outcome measures were reduction of depressive symptoms and attrition rate. METHODS: Ninety-six psychiatric patients with MDD (DSM-IV) were randomized to 14 sessions of CBT (n = 48) or IPT (n = 48). A noninferiority design was used with the hypothesis that IPT would be noninferior to CBT. A three-point difference on the Beck Depression Inventory-II (BDI-II) was used as noninferiority margin. RESULTS: IPT passed the noninferiority test. In the ITT group, 53.5% (23/43) of the IPT patients and 51.0% (24/47) of the CBT patients were reliably improved, and 20.9% (9/43) and 19.1% (9/47), respectively, were recovered (last BDI score <10). The dropout rate was significantly higher in CBT (40%; 19/47) compared to IPT (19%; 8/43). Statistically controlling for antidepressant medication use did not change the results. CONCLUSIONS: IPT was noninferior to CBT in a sample of depressed psychiatric patients in a community-based outpatient clinic. CBT had significantly more dropouts than IPT, indicating that CBT may be experienced as too demanding. Since about half the patients did not recover, there is a need for further treatment development for these patients. The study should be considered an effectiveness trial, with strong external validity but some limitations in internal validity.

Patterning on nonplanar substrates: flexible honeycomb films from a range of self-assembling star copolymers.

The effect of glass transition temperature, Tg, on the self-assembly of "honeycomb" microstructures on nonplanar substrates was probed by the synthesis of a library of core cross-linked star polymers with different arm compositions. Star polymers based on poly(dimethyl siloxane), poly(ethyl acrylate), poly(methyl acrylate), poly(tert-butyl acrylate), and poly(methyl methacrylate) were synthesized by the "arm first" strategy using atom-transfer radical polymerization. Reaction conditions were optimized, and a series of high molecular weight star polymers were prepared in high yield. The glass transition temperature of the star polymers ranged from -123 to 100 degrees C which allowed the suitability for the formation of porous honeycomb-like films via the "breath figure" technique on nonplanar surfaces to be investigated. All star compositions successfully formed ordered films on flat surfaces. However, only star polymer compositions with a Tg below 48 degrees C could form homogeneous honeycomb coatings on the surface of nonplanar substrates.

Synthesis of well-defined hydrogel networks using click chemistry.

New PEG-based hydrogel materials have been synthesized by Click chemistry and shown to result in well-defined networks having significantly improved mechanical properties; the selectivity of the azide/acetylene coupling reaction also allows for the incorporation of various additives and functional groups leading to chemical tailoring of the hydrogels.

Multivalent, bifunctional dendrimers prepared by click chemistry.

Unsymmetrical dendrimers, containing both mannose binding units and coumarin fluorescent units, have been prepared using click chemistry and shown to be highly efficient, dual-purpose recognition/detection agents for the inhibition of hemagglutination.

A modular approach toward functionalized three-dimensional macromolecules: from synthetic concepts to practical applications.

A new strategy for the preparation of functional, multiarm star polymers via nitroxide-mediated "living" radical polymerization has been explored. The generality of this approach to the synthesis of three-dimensional macromolecular architectures allows for the construction of nanoscopically defined materials from a wide range of different homo, block, and random copolymers combining both apolar and polar vinylic repeat units. Functional groups can also be included along the backbone or as peripheral/chain end groups, thereby modulating the reactivity and polarity of defined portions of the stars. This modular approach to the synthesis of three-dimensional macromolecules permits the application of these tailored materials as multifunctional hosts for hydrogen bonding, nanoparticle formation, and as scaffolds for catalytic groups. Examples of applications of the functional stars in catalysis include their use in a Heck-type coupling as well as an enantioselective addition reaction.