Liver tissue engineering is hampered by poor implanted cell survival due to inadequate vascularization and cell-cell/cell-matrix interactions. Here, we use liver progenitor cell (LPC) spheroids to enhance cell-cell/cell-matrix interactions, with implantation into an angiogenic in vivo mouse chamber. Spheroids were generated in vitro in methylcellulose medium. Day 2 spheroids were optimal for implantation (22,407 +/-645 cells/spheroid), demonstrating maximal proliferation (Ki67 immunolabeling) and minimal apoptosis (caspase-3 immunolabelling). In vivo chambers established bilaterally on epigastric vessels of immunodeficient mice were implanted with equivalent numbers of LPCs as a cell suspension (200,000 cells), or spheroids (9 spheroids). At day 14, a trend of increased LPC survival was observed in spheroid-implanted chambers [pan-cytokeratin (panCK+) cells, p = 0.38, 2.4 fold increase)], with significantly increased differentiation [cytokeratin 18 (CK18+) cells, p < 0.002, 5.1 fold increase)] compared to cell suspension-implanted chambers. At day 45, both measures were significantly increased in spheroid-implanted chambers (panCK, p < 0.006, 16 fold increase) (CK18, p < 0.019, 6 fold increase). Hepatic acini/plates of CK18 + cells expressed hepatocyte nuclear factor 4-α and β-catenin, indicating ongoing hepatic differentiation. Spheroid cell-delivery significantly increased LPC survival and differentiation compared to conventional cell suspensions. This LPC spheroid/vascularized chamber model has clinical potential to generate three-dimensional vascularized liver tissue for liver replacement.
A retrospective study of 48 unselected patients with myasthenia gravis was undertaken to evaluate the head and neck manifestations of this disease and to examine the role of the otolaryngologist in diagnosis and management. Oropharyngeal features were found in 56% of patients at presentation. In 20 the initial complaint was of one or more symptoms referable to the upper aerodigestive tract, whilst in 9 (18.8%) these were the only symptoms. The importance of maintaining a high index of clinical suspicion is emphasized, as the early muscle weakness is invariably mild and fluctuant. Contemporary aspects of the aetiology, diagnosis and management are considered. Particular attention is focused on the characteristics of the stapedius reflex in this disorder, as this is probably the most sensitive objective test for assessing defective neuromuscular transmission.
The sterile bag rubbing technique is a quicker alternative method for surgical site preparation in hand surgery and has comparable efficacy to the widely practised standard paint-on technique.
We describe here a technique for reconstruction of the external ear based upon an autogenous costal cartilage graft which is inserted into a cutaneous pocket dissected in the auricular area. Three subsequent procedures are then performed: rotation of the ear-lobe; reconstruction of the tragus; and elevation of the auricle. The ideal age for reconstruction is about 7 years. This technique was originally described by Brent, who has a very extensive experience with this kind of surgery. Skin deficiencies can be overcome by using either a temporo-parietal fascial flap or a skin expander.
Key Clinical MessagePatent Blue dye for sentinel lymph node biopsy is associated with systemic allergic response and generalized blue hue. We report a unique case of successful free flap transfer in this setting. Despite inotropic support and abnormal blue hue, allergic response does not preclude safe flap transfer and monitoring.
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