Sarunas Petronis

Donor veins were decellularized and reconditioned with the recipient's blood to produce autologous personalized tissue engineered veins. After 1 year in vivo, all grafts were patent and morphologically and genetically very similar with native veins.

Background: Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation. Methods: We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP. Results: High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14–15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06–0.59], p = 0.005, and OR 0.34 [95% CI 0.13–0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17–1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation. Conclusion: High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed. Trial registration: ClinicalTrials.gov NCT02284438. Retrospectively registered on 21 October 2014.

Purpose Intermittent catheterization (IC) is a proven effective long-term bladder management strategy for individuals who have lower urinary tract dysfunction. This study provides clinical evidence about multiple-reuse versus single-use catheterization techniques and if catheter choice can have an impact on health-related quality of life (HRQoL). Method A prospective, multi-center, clinical trial studied patients who currently practiced catheter reuse, and who agreed to prospectively evaluate single-use hydrophilic-coated (HC) (i.e. LoFric) catheters for 4 weeks. A validated Intermittent Self-Catheterization Questionnaire (ISC-Q) was used to obtain HRQoL. Reused catheters were collected and studied with regard to microbial and debris contamination. Results The study included 39 patients who had practiced IC for a mean of 10 years, 6 times daily. At inclusion, all patients reused catheters for a mean of 21 days (SD = 48) per catheter. 36 patients completed the prospective test period and the mean ISC-Q score increased from 58.0 (SD = 22.6) to 67.2 (SD = 17.7) when patients switched to the single-use HC catheters (p = 0.0101). At the end of the study, 83% (95% CI [67–94%]) preferred to continue using single-use HC catheters. All collected reused catheters (100%) were contaminated by debris and 74% (95% CI [58–87%]) were contaminated by microorganisms, some with biofilm. Conclusion Single-use HC catheters improved HRQoL and were preferred over catheter reuse among people practicing IC. Catheter multiple-reuse may pose a potential safety concern due to colonization by microorganisms as well as having reduced acceptance compared to single use. Trial registry number ClinicalTrials.gov NCT02129738.

Alveolar bone loss is usually treated with guided bone regeneration, a dental procedure which utilizes a tissue-separation membrane. The barrier membrane prevents pathogens and epithelial cells to invade the bone augmentation site, thereby permitting osteoblasts to deposit minerals and build up bone. This study aims at adding bioactive properties to otherwise inert PTFE membranes in order to enhance cell adherence and promote proliferation. A pre-wetting by ethanol and stepwise hydration protocol was herein employed to overcome high surface tension of PTFE membranes and allow for a recombinant spider silk protein, functionalized with a cell-binding motif from fibronectin (FN-silk), to self-assemble into a nanofibrillar coating. HaCaT and U-2 OS cells were seeded onto soft and hard tissue sides, respectively, of membranes coated with FN-silk. The cells could firmly adhere as early as 1 hour post seeding, as well as markedly grow in numbers when kept in culture for seven days. Fluorescence and scanning electron microscopy images revealed that adherent cells could form a confluent monolayer and develop essential cell-cell contacts during one week of culture. Hence, functionalized PTFE membranes have a potential of better integration at the implantation site, with reduced risk of membrane displacement as well as exposure to oral pathogens.

In this study, several surface topographies typical for dental implants were evaluated by different measurement techniques. The samples were prepared by machine turning, wet chemical etching and electrochemical polishing of titanium discs. The measurement techniques included an atomic force microscope (AFM), coherence scanning interferometer (CSI) and a 3D stereo scanning electron microscope (SEM). The aim was to demonstrate and discuss similarities and differences in the results provided by these techniques when analyzing submicron surface topographies. The estimated surface roughness parameters were not directly comparable since the techniques had different surface spatial wavelength band limits. However, the comparison was made possible by applying a 2D power spectral density (PSD) function. Furthermore, to simplify the comparison, all measurements were characterized using the ISO 25178 standard parameters. Additionally, a Fourier transform was applied to calculate the instrument transfer function in order to investigate the behavior of CSI at different wavelength ranges. The study showed that 3D stereo SEM results agreed well with AFM measurements for the studied surfaces. Analyzed surface parameter values were in general higher when measured by CSI in comparison to both AFM and 3D stereo SEM results. In addition, the PSD analysis showed a higher power spectrum density in the lower frequency range 10 ⁻² –10 ⁻¹ µ m ⁻¹ for the CSI compared with the other techniques.