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Biocompatible hydrogels have a wide variety of potential applications in biotechnology and medicine, such as the controlled delivery and release of cells, cosmetics and drugs; and as supports for cell growth and tissue engineering1. Rational peptide design and engineering are emerging as promising new routes to such functional biomaterials2-4. Here we present the first examples of rationally designed and fully characterized self-assembling hydrogels based on standard linear peptides with purely α-helical structures, which we call hydrogelating self-assembling fibres (hSAFs). These form spanning networks of α-helical fibrils that interact to give self-supporting physical hydrogels of >99% water content. The peptide sequences can be engineered to alter the underlying mechanism of gelation and, consequently, the hydrogel properties. Interestingly, for example, those with hydrogen-bonded networks melt upon heating, whereas those formed via hydrophobic interactions strengthen when warmed. The hSAFs are dual-peptide systems that only gel on mixing, which gives tight control over assembly5. These properties raise possibilities for using the hSAFs as substrates in cell culture. We have tested this in comparison with the widely used Matrigel substrate, and demonstrate that, like Matrigel, hSAFs support both growth and differentiation of rat adrenal pheochromocytoma cells for sustained periods in culture.

SummaryBackground-Stem-cell-based, tissue engineered transplants might offer new therapeutic options for patients, including children, with failing organs. The reported replacement of an adult airway using stem cells on a biological scaffold with good results at 6 months supports this view. We describe the case of a child who received a stem-cell-based tracheal replacement and report findings after 2 years of follow-up.

Objective: Raman spectroscopy, the analysis of scattered photons after monochromatic laser excitation, is well established in nonbiological sciences. Recently this method has been used to differentiate premalignant and malignant lesions from normal tissue. Its application for early diagnosis has been explored in a variety of sites (e.g., esophagus, cervix), but not, to date, in laryngeal cancer. The objective of this study was to perform a feasibility study of the use of Raman spectroscopy for early diagnosis of laryngeal malignancy. Methods: Biopsy specimens were snapfrozen, and top sections were sent for histopathological analysis. Only homogenous samples with clearly defined pathological findings were used in this study: seven histologically normal samples, four exhibiting dysplasia, and four with carcinoma. Samples were defrosted and placed under a Renishaw (WottonUnder-Edge, UK) System 1000 Raman microspectrometer for analysis. Between 5 and 12 spectra were acquired from each sample, with an excitation wavelength of 830 nm. Average characteristic spectra for each disease or condition were compared. Further multivariate statistical analysis of the data was carried out to evaluate and maximize the differences in the spectra for each disease or condition. Results: The most visible differences in the spectra occur between 850 and 950 cm ؊1 and 1200 and 1350 cm ؊1. The later peaks are directly related to protein conformation and C-H bond stretch in nucleic acid bases. The relative intensity of the nucleic acid peak increases with progression to malignancy. Use of linear discriminant analysis made it possible to separate the spectra with disease to a greater degree of accuracy than using empirical peak ratio methods alone. Classification results obtained from cross-validation of the discriminant model showed prediction sensitivities of 83%, 76%, and 92% and specificities of 94%, 91%, and 90% for normal, dysplastic, and squamous cell carcinoma of the larynx, respectively. Conclusions: There was strong evidence to support spectral identification of malignancy and earlier abnormal changes. More substantive studies of the spectral differences between malignant and non-neoplastic tissue are warranted. Raman spectroscopy may become a useful adjunct to pathological diagnosis allowing directed or guided biopsies and assessment of adequacy of resection margins.

Rationale: Stem cell-based tracheal replacement represents an emerging therapeutic option for patients with otherwise untreatable airway diseases including long-segment congenital tracheal stenosis and upper airway tumors. Clinical experience demonstrates that restoration of mucociliary clearance in the lungs after transplantation of tissue-engineered grafts is critical, with preclinical studies showing that seeding scaffolds with autologous mucosa improves regeneration. High epithelial cell-seeding densities are required in regenerative medicine, and existing techniques are inadequate to achieve coverage of clinically suitable grafts.Objectives: To define a scalable cell culture system to deliver airway epithelium to clinical grafts.Methods: Human respiratory epithelial cells derived from endobronchial biopsies were cultured using a combination of mitotically inactivated fibroblasts and Rho-associated protein kinase (ROCK) inhibition using Y-27632 (3T31Y). Cells were analyzed by immunofluorescence, quantitative polymerase chain reaction, and flow cytometry to assess airway stem cell marker expression. Karyotyping and multiplex ligation-dependent probe amplification were performed to assess cell safety. Differentiation capacity was tested in three-dimensional tracheospheres, organotypic cultures, air-liquid interface cultures, and an in vivo tracheal xenograft model. Ciliary function was assessed in air-liquid interface cultures.

Introduction 5 Cell and Gene Therapy 9 Modification of splicing: Antisense oligonucleotides and small molecules 21 Tissue Engineering 24 Small trials, difficult statistics, difficult regulation and data reproducibility. 28 Health economics of regenerative medicine 31 Regulation of stem cell therapies and regenerative medicine 41 Ethics 43 Public engagement and trust 54 Conclusions 56

Objectives: To measure morbidity and mortality rates following insertion of gastrostomy tubes in head and neck cancer patients. To determine evidence for any relationship between gastrostomy insertion technique and complication rates. Design: A prospective cohort study and qualitative systematic review. Setting: Multi-cancer networks in the South West of England, Hampshire and the Isle of White. Participants: One hundred and seventy-two patients with head and neck cancer undergoing gastrostomy tube insertion between 2004 and 2005. Percutaneous endoscopic gastrostomy (PEG) was performed in 121 patients. Fifty-one patients had radiologically inserted gastrostomy (RIG). Twenty-seven studies reporting outcomes following 2353 gastrostomy procedures for head and neck cancer. Main outcome measures: Post-procedure mortality, major and minor complications. Results: In the present series, mortality rates were 1.0% (1 ⁄ 121) for PEG and 3.9% (2 ⁄ 51) for RIG. Overall major complication rates following PEG and RIG were 3.3% (4 ⁄ 121) and 15.6% (9 ⁄ 51) respectively. In our systematic review and meta-analysis of 2379 head and neck cancer patients, we observed fatality rates of 2.2% (95% CI 0.014-0.034) following PEG and 1.8% (95% CI 0.010-0.032) following RIG. Furthermore, major complication rates following PEG were 7.4% (95% CI 5.9-9.3%) and 8.9% (95% CI 7.0-11.2%) after RIG. Conclusions: Procedure related mortality rates following gastrostomy in head and neck cancer patients are higher than those in mixed patient populations. Major complication rates following RIG in head and neck cancer patients are greater than those following PEG. Major complications following PEG in patients with head and neck cancer appear no worse than in mixed pathology groups. We have identified that RIG is associated with increased morbidity and mortality in patients who are ineligible for PEG. The serious nature of the complications associated with gastrostomy particularly in patients with head and neck cancer requires careful consideration by the referring physician.The optimum technique for gastrostomy placement in patients with head and neck cancer remains controversial.1-4 Examination of the literature relating to complication and success rates of gastrostomy is made difficult by patient and pathology diversity and modifications of insertion technique. In 1995, Wollman et al.5 reported a metaanalysis investigating outcomes of 5752 patients following radiologic, endoscopic and surgical gastrostomy for all types of pathology. The authors concluded that radiologically inserted gastrostomies (RIG) were slightly more successful than percutaneous endoscopic gastrostomy (PEG) (99.2% versus 95.7%) and also safer, with statistically significant lower rates of major complications (5.9% versus 9.4%). Cancer comprised only 24-29% of the study populations and interpretation of the results in the context of head and neck cancer practice remains exigent. In this study, we examine outcomes following gastrostomy tube insertion in 172 consecutive patients trea...

Management of intestinal failure remains a clinical challenge and total parenteral nutrition, intestinal elongation and/or transplantation are partial solutions. In this study, using a detergent-enzymatic treatment (DET), we optimize in rats a new protocol that creates a natural intestinal scaffold, as a base for developing functional intestinal tissue. After 1 cycle of DET, histological examination and SEM and TEM analyses showed removal of cellular elements with preservation of the native architecture and connective tissue components. Maintenance of biomechanical, adhesion and angiogenic properties were also demonstrated strengthen the idea that matrices obtained using DET may represent a valid support for intestinal regeneration.