Investigating the clinical significance of mesh peritonization in abdominal vault suspension surgery using a comparative rabbit model.

OBJECTIVE: To investigate the clinical significance of mesh peritonization in an experimental rabbit model. STUDY DESIGN: Twenty rabbits were randomly assigned to two groups. A sacrouteropexy operation was performed in both groups using a polypropylene mesh. In the first group, the pelvic peritoneum was not closed over the mesh, and in the second group, the mesh was buried throughout the pelvic retroperitoneal tunnel. One month after mesh implantation, the abdomen was opened and the previous surgical site was explored. The primary outcome was intraabdominal adhesion formation; the secondary outcome was the histologic degree of tissue remodeling. RESULTS: There were no statistically significant differences between the two groups in terms of adhesion scores and collagen organization (P=0.692, P=0.097, respectively). There was a greater degree of inflammation in the second group as identified by significantly higher scores for eosinophils-neutrophils, macrophages-foreign body giant cells and mononuclear cells (P=0.002, P=0.001 and P=0.002, respectively). CONCLUSIONS: Similar adhesion and collagen organization patterns were found in both groups, but indicators of the inflammatory process were significantly higher in the second group.

Amphoteric surface hydrogels derived from hydrogen-bonded multilayers: reversible loading of dyes and macromolecules.

We used hydrogen-bonded multilayers of poly(N-vinylpyrrolidone) (PVPON) and poly(methacrylic acid) (PMAA) as precursors for producing surface-bound hydrogels and studied their pH-dependent swelling and protein uptake behavior using in situ attenuated total reflection Fourier transform infrared spectroscopy and in situ ellipsometry. The hydrogels were produced by selective chemical cross-linking between PMAA units using carbodiimide chemistry and ethylenediamine (EDA) as a cross-linking reagent, followed by complete removal of PVPON from the film obtained by exposing the film to pH 7.5. As shown by in situ ellipsometry, hydrogels exhibit distinctive polyampholytic swelling as a function of pH, with minimum swelling at pH 4.2-5.7, and increased film thickness at both lower and higher pH values. Film swelling at lower pH values occurs as a result of the presence of amino groups within the hydrogels, which originate from the one-end attachment of the EDA cross-linker to PMAA chains. The pH-switching of hydrogel swelling was fast and reversible. The degree of hydrogel swelling could be also controlled by varying the time allowed for cross-linking. The produced hydrogels were able to absorb large amounts of dyes and proteins of opposite charge reversibly, in response to pH variations. Finally, we demonstrate that proteins included within the hydrogel can easily be replaced with linear polycations. These surface hydrogels hold promise for bioseparation and controlled delivery applications.