Lipase mediated enzymatic degradation of polydioxanone in solution

The enzymatic biodegradation of polydioxanone (PDO) in trifluoroethanol (TFE) at various temperatures (25-55 degrees C) was studied with two different types of lipases, namely immobilized enzyme Novozym 435 and free enzyme porcine pancreas lipase. The biodegradation process was monitored by gel permeation chromatography (GPC). Both enzymes showed the optimum activity at 37 degrees C and Novozym 435 exhibited better thermal stability over the experimental temperature range. A continuous distribution kinetic model was employed to describe the biodegradation process and the model was used to fit the experimental data satisfactorily and obtain kinetic parameters. (C) 2014 Elsevier Ltd. All rights reserved.

Sutura arterial com técnicas contínua e de pontos separados, utilizando-se os fios polipropilene e polidioxanone: estudo experimental em coelhos

OBJETIVO: Observar o comportamento da sutura arterial em aortas abdominais de coelhos em crescimento, comparando-se as técnicas contínua e com pontos separados, empregando-se dois tipos de fios: Polipropilene 7-0 (inabsorvível) e Polidioxanone 7-0 (absorvível). MÉTODOS: Grupos: GI - Controle (sem sutura); GII - Polipropilene, Pontos Separados; GIII - Polipropilene, Contínua; GIV - Polidioxanone, Pontos Separados e GV - Polidioxanone, Contínua. Cada grupo foi subdividido em quatro Momentos de Eutanásia: aos 7, 14, 30 e 60 dias de pós-operatório. Foram avaliados: peso dos animais, diâmetros e pulsos arteriais, estenose, trombose, aderências, aortografia, visibilidade do fio, cicatrização e microscopia. RESULTADOS: a) após 60 dias, o local da linha de sutura cresceu de forma significativa em todos os grupos; b) a técnica de sutura com pontos separados causou menor estenose da linha de sutura, observada tanto no ato cirúrgico, como na eutanásia dos animais; c) no exame histopatológico, as diferenças encontradas entre grupos foram transitórias, não persistindo após 60 dias de pós-operatório. CONCLUSÃO: O polidioxanone mostrou ser a melhor opção, entre os dois fios, para sutura de artérias em crescimento, pois causa pouca ou nenhuma restrição ao crescimento arterial na linha de sutura, mesmo quando se emprega a técnica contínua.

Effects of Ciprofloxacin-containing Scaffolds on Enterococcus faecalis Biofilms

Introduction: Antibiotic-containing polymer-based nanofibers (hereafter referred to as scaffolds) have demonstrated great potential for their use in regenerative endodontics from both an antimicrobial and cytocompatibility perspective. This study sought to evaluate in vitro the effects of ciprofloxacin (CIP)-containing polymer scaffolds against Enterococcus faecalis biofilms. Methods: Human mandibular incisors were longitudinally sectioned to prepare radicular dentin specimens. Sterile dentin specimens were distributed in 24-well plates and inoculated with E. faecalisfor biofilm formation. Infected dentin specimens were exposed to 3 groups of scaffolds, namely polydioxanone (PDS) (control), PDS + 5 wt% CIP, and PDS + 25 wt% CIP for 2 days. Colony-forming units (CFU/mL) (n = 10) and scanning electron microscopy (SEM) (n -= 2) were performed to quantitatively and qualitatively assess the antimicrobial effectiveness, respectively. Results: PDS scaffold containing CIP at 25 wt% showed maximum bacteria elimination with no microbial growth, differing statistically (P < .05) from the control (PDS) and from PDS scaffold containing CIP at 5 wt%. Statistical differences (P < .05) were also seen for the CFU/mL data between pure PDS (5.92-6.02 log CFU/mL) and the PDS scaffold containing CIP at 5 wt% (5.39 5.87 log CFU/mL). SEM images revealed a greater concentration of bacteria on the middle third of the dentin specimen. after 5 days of biofilm formation. On scaffold exposures, SEM images showed similar results when compared with the CFU/mL data. Dentin specimens exposed to PDS + 25 wt% CIP scaffolds displayed a practically bacteria-free surface. Conclusions: On the basis of the data presented, newly developed antibiotic-containing electrospun scaffolds hold promise as an intracanal medicament to eliminate biofilm/infection before regenerative procedures.

Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

Objective: To investigate the VEGF expression and collagen deposition using a latex biomembrane as bladder replacement in rabbits. Materials and Methods: After partial cystectomy, a patch of a non-vulcanized latex biomembrane (2 x 2 cm) was sewn to the bladder of rabbits with 5/0 monofilament polydioxanone sulfate sutures in a watertight manner. Groups of 5 animals were killed at 15, 45 and 90 days after surgery and the bladder was removed. Sections of 5 mu m were cut and stained with picrosirius-red in order to estimate the amount of extracellular matrix in the graft. To confirm the presence of VEGF in tissues, protein expression was determined by immunohistochemistry. Results: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. A progressive reduction in the amount of collagen occurred in the graft area and was negatively and linearly correlated with time (p < 0.001). VEGF expression was higher in grafted areas when compared to controls at 15 and 45 days after surgery and decreased with time (p < 0.001). Conclusion: The latex biomembrane as a matrix for partial bladder replacement in rabbits promotes temporary collagen deposition and stimulates the angiogenic process.

Anastomotic strictures in colorectal surgery: treatment with endoscopic balloon dilation

The incidence of anastomotic stricture following colorectal surgery has increased in recent years. This complication is observed in 2-5% of all operated patients and is probably due to the greater number of low anastomoses performed with surgical staplers. We observed 31 patients with postoperative stricture, arising from one to nine months post-surgery. All patients had been treated for colorectal cancer and underwent endoscopy either during routine follow-up or for symptoms of stenosis. In 16 patients (group A) the stricture diameter was less than 4 mm and the patients had symptoms attributable to partial bowel obstruction. In the remaining 15 patients (group B), who had difficult bowel movements, the stricture diameter ranged from 4 to 8 mm. All patients were treated with endoscopic dilation using achalasia balloons. The results were considered good when the post-dilation anastomosis diameter achieved was at least 13 mm, fair when it was 9-12 mm and poor when it was less than 9 mm. The short term results (3 weeks) were good in 27 patients (87.2%), fair in 3 patients (9.6%), and poor in 1 patient (3.2%). After several unsuccessful dilations, the latter was treated by surgery. Follow-up at 3-4 months of the remaining 30 patients revealed good results in 20 (66.6%), fair in 6 (20%), and poor in 4 (13.3%). In 1 of these 4 patients, cancer recurrence was observed and a new surgical resection was performed. In 2 patients a self–expandable metal stent was inserted for 4-6 weeks, with satisfactory results. In 1 patient a biodegradable polydioxanone stent was inserted with good results after 6 months. Follow-up at 3-4 months showed good results in 25 patients. After 38 months, cancer recurrence in the area of the anastomosis was observed in 1 patient, who was treated surgically. Endoscopic dilatation should be considered the first therapeutic approach in case of anastomotic strictures, as it is immediately effective, repeatable, and does not preclude surgery if this should become necessary. .