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Engineering three-dimensional (3D) scaffolds with in vivo like architecture and function has shown great potential for tissue regeneration. Here we developed a facile microfluidic-based strategy for the continuous fabrication of cell-laden microfibers with hierarchically organized architecture. We show that photolithographically fabricated microfluidic devices offer a simple and reliable way to create anatomically inspired complex structures. Furthermore, the use of photo-cross-linkable methacrylated alginate allows modulation of both the mechanical properties and biological activity of the hydrogels for targeted applications. Via this approach, multilayered hollow microfibers were continuously fabricated, which can be easily assembled in situ, using 3D printing, into a larger, tissue-like construct. Importantly, this biomimetic approach promoted the development of phenotypical functions of the target tissue. As a model to engineer a complex tissue construct, osteon-like fiber was biomimetically engineered, and enhanced vasculogenic and osteogenic expression were observed in the encapsulated human umbilical cord vein endothelial cells and osteoblast-like MG63 cells respectively within the osteon fibers. The capability of this approach to create functional building blocks will be advantageous for bottom-up regeneration of complex, large tissue defects and, more broadly, will benefit a variety of applications in tissue engineering and biomedical research.

Background: DNA repair mechanisms are crucial for maintenance of the genome in all organisms, including parasites where successful infection is dependent both on genomic stability and sequence variation. MSH2 is an early acting, central component of the Mismatch Repair (MMR) pathway, which is responsible for the recognition and correction of base mismatches that occur during DNA replication and recombination. In addition, recent evidence suggests that MSH2 might also play an important, but poorly understood, role in responding to oxidative damage in both African and American trypanosomes., Methodology/principal Findings: To investigate the involvement of MMR in the oxidative stress response, null mutants of MSH2 were generated in Trypanosoma brucei procyclic forms and in Trypanosoma cruzi epimastigote forms. Unexpectedly, the MSH2 null mutants showed increased resistance to H2O2 exposure when compared with wild type cells, a phenotype distinct from the previously observed increased sensitivity of T. brucei bloodstream forms MSH2 mutants. Complementation studies indicated that the increased oxidative resistance of procyclic T. brucei was due to adaptation to MSH2 loss. In both parasites, loss of MSH2 was shown to result in increased tolerance to alkylation by MNNG and increased accumulation of 8-oxo-guanine in the nuclear and mitochondrial genomes, indicating impaired MMR. In T. cruzi, loss of MSH2 also increases the parasite capacity to survive within host macrophages., Conclusions/significance: Taken together, these results indicate MSH2 displays conserved, dual roles in MMR and in the response to oxidative stress. Loss of the latter function results in life cycle dependent differences in phenotypic outcomes in T. brucei MSH2 mutants, most likely because of the greater burden of oxidative stress in the insect stage of the parasite.

Objective: To develop and validate a pictorial chart that documents ultrasound examination of the anal sphincter., Design: A new pictorial chart (Liverpool Ultrasound Pictorial Chart [LUPIC]) depicting the normal anatomy of the anal sphincter was developed., Methods: To validate LUPIC, two observers documented the findings of 296 endoanal scans. Reliability was assessed between observers using kappa agreement for presence and position of sphincter defects. To validate the use of LUPIC by different observers, a video of ten endoanal ultrasound scans was reviewed by our local expert (gold standard). Seven clinicians underwent test-retest analysis. Kappa agreement was calculated to assess intra-observer and gold standard versus observer agreement for the overall presence of sphincter defects and compared with the gold standard. Complete agreement for the position and level of sphincter defects was assessed for the five abnormal scans., Main Outcome Measures: Excellent agreement between the two observers was found for the presence (kappa 0.99), position and level of external anal sphincter defects documented using LUPIC. The intra-observer and gold standard versus observer kappa values of experienced clinicians (A-E) showed good agreement for the overall presence of sphincter defects. Complete agreement for the position and level of sphincter defects was found in 23 of 35 (66%) observations., Conclusions: LUPIC is designed and validated method of documenting anal sphincter injury diagnosed by endoanal ultrasound. Standardisation of endoanal ultrasound findings by using LUPIC may help correlate the degree of damage with patient symptoms.

The aim of this study was to assess the impact of a new guideline on the outcome of repair of obstetric anal sphincter tears by examining adherence to the guideline and the effect upon the incidence of symptoms of anal incontinence. An audit of third-degree perineal tears was conducted in 1997. A reaudit was completed in 1998 and 1999 after the introduction of a new guideline. The audits were conducted in a tertiary obstetric unit with 5000 deliveries per annum. Over the 3-year period between 1997 and 1999 124 women with a third-degree tear were identified; 14 381 women who had delivered vaginally without third-degree tears were used as controls. The main outcome measure was the number of cases with adherence to the protocol, and the number of patients with ongoing symptoms. Cases were identified from the hospital database, and case notes were reviewed to obtain clinical data. The incidence of third-degree perineal tears was 0.81% over the 3-year period. Following the introduction of a new guideline there was a significant increase in the number of repairs performed in theatre (70% vs 82% vs 97%, P<0.05), using Prolene (64% vs 76% vs 93%, P< 0.05), with adequate anesthesia (70% vs 82% vs 97%, P<0.05). At follow-up there was a transient improvement in defecatory symptoms in the first year of the protocol only (45% vs 32% vs 50%, P<0.01). More patients had complete follow-up data after introduction of the protocol: 66% vs 86% vs 80% ( P<0.001). There were more cases of Prolene suture migration (7% vs 34% vs 16%, P<0.01). We concluded that the introduction of a new guideline was followed by improved performance of appropriate repair. There was no sustained improvement in fecal symptoms at follow-up.