Assessment of the Safety of Chondrocyte Sheet Implantation for Cartilage Regeneration.

We have previously studied the effects of chondrocyte sheets on the repair and regeneration of articular cartilage by using temperature-responsive culture inserts. On the basis of this work, we succeeded in rapid fabrication of chondrocyte sheets with the use of a coculture method in which inserts were placed between synoviocytes and chondrocytes. Treatment of cartilage defects using layered chondrocyte sheets promotes repair and regeneration; this method is compatible with in vivo osteoarthritis models that reproduce partial-thickness defects. In human stem cell clinical research guidelines, the Ministry of Health, Labour and Welfare (MHLW) approved several applications related to this technology. Indeed, its translation to a clinical setting is already yielding favorable results. In this study, we evaluated the risk of tumorigenesis associated with this treatment and characterized the dynamics of biological processes associated with the posttransplantation cell sheets in vivo. Furthermore, we also confirmed the safety of the procedure by using array comparative genomic hybridization (array CGH) and G-band staining to screen for deleterious genetic aberrations during prolonged subculture of cells. The safety of chondrocytes that were cultured for longer than normal was confirmed by the array CGH and G-band staining results. In addition, tumorigenicity testing confirmed that culture chondrocyte sheets are not tumorigenic. Furthermore, from the evaluation of bioluminescence imaging following implantation of the cell sheets, it was confirmed that the transplanted chondrocytes and synoviocytes remained in the knee joint and did not transfer elsewhere over time. We believe that the technique used in this study is a highly useful method for evaluating the safety of not only chondrocytes but also extensive subculturing in general.

In vivo cell tracking by bioluminescence imaging after transplantation of bioengineered cell sheets to the knee joint.

In our previous studies, we have demonstrated effective regeneration of cartilage through the creation and application of layered cell sheets that combine both chondrocytes and synovial cells. In this study, we were able to demonstrate that cells derived from cell sheets can survive for long periods after transplantation into rat knee joints having osteochondral defects. We established a method for generating cell sheets from firefly luciferase-expressing chondrocytes obtained from transgenic Lewis rats, and carried out allogenic transplantation of these cell sheets into wild-type Lewis rats. We then administered luciferin and monitored the survival of the transplanted cells by using bioluminescence imaging (BLI). Our data showed that the transplanted cells survived and could be detected for more than 21 months, which was longer than expected. Furthermore, the BLI data showed that the transplanted cells remained in the knee joint and did not migrate to other parts of the body, thus confirming the safety of the cell sheets. In this study, we monitored the duration of survival of cell sheets composed of only chondrocytes, only synovial cells, or both chondrocytes and synovial cells, and found that all three types of cell sheets survived for an extended period of time.

[Successful tracheal intubation using the pediatric Airtraq optical laryngoscope in a pediatric patient with Robin sequence].

We report a successful use of pediatric Airtraq optical laryngoscope in a pediatric patient with Robin sequence. Robin sequence accompanies a characteristic facies and its clinical presentation is marked by micrognathia, retrognathia, glossoptosis, and respiratory obstruction. A 1-year-5 month-old boy with Robin sequence was scheduled for palate repair under general anesthesia. After anesthetic induction with thiopental and neuromuscular paralysis with rocuronium, initial laryngeal view with the conventional Macintosh laryngoscope was Cormack-Lehane grade II due to restricted mouth opening and micrognathia. The Airtraq Pedi provided the glottic view with Cormack-Lehane grade I and a preformed tracheal tube (ID 4 mm) was placed correctly into the trachea through the built-in tube channel. We conclude that the pediatric Airtraq has potential advantages over conventional direct laryngoscopy in children with difficult airway.

[Nasal endotracheal intubation using GlideScope].

We describe the performance of GlideScope in 34 consecutive patients who required nasal endotracheal intubation for surgical convenience. In the 34 patients, nasal endotracheal intubation was achieved in 52 +/- 22 (mean +/- SD) sec by unexperienced clinicians, and in 50 +/- 17 sec by anesthetists in the department. Margill forceps were not needed for any patient during nasotracheal intubation. The improved coordination afforded by an image on a video monitor seen by both the assistant providing laryngeal manipulation and the anesthetist handling the laryngoscope resulted in a significant advantage over the conventional laryngoscope technique. GlideScope seems to be a novel useful device for nasal endotracheal intubation.