* Coculture with Partial Digestion Notochordal Cell-Rich Nucleus Pulposus Tissue Activates Degenerative Human Nucleus Pulposus Cells.

Recent studies suggested that notochordal cells (NCs) and NC-conditioned medium (NCCM) can stimulate cell viability and matrix production of nucleus pulposus cells (NPCs). However, the potential of notochordal cell-rich nucleus pulposus (NRNP) incorporating the native environment of the intervertebral disc (IVD) has not been evaluated. The objective of this study was to develop an optimal NRNP model and test whether it can allow a significant level of NPC activation in vitro. Rabbit NRNP explants were divided into three groups according to different digestion time: digestion NRNP of 8 h, partial digestion NRNP of 2 h, and natural NRNP. Cell viability and NC phenotype were compared between these groups after 14 days of incubation. The products of the selected partial digestion NRNP group were then cocultured with human degenerated NPCs for 14 days. NPC viability, cell proliferation and senescence, the production of glycosaminoglycan (GAG) found in extracellular matrix, and NP matrix production by NPCs were assessed. The results showed that coculturing with partial digestion NRNP significantly improved the cell proliferation, cell senescence, and disc matrix gene expression of NPCs compared with those in the monoculture group. In addition, GAG/DNA ratio in the coculture group increased significantly, while the level of collagen II protein remained unchanged. In this study, we demonstrated that partial digestion NRNP may show a promising potential for NPC regeneration in IVD tissue engineering.

Relation between eardrum flap area and healing outcome of traumatic eardrum perforation.

OBJECTIVE: To retrospectively study the clinical effects of eardrum flap area on the healing outcome following traumatic perforation. METHODS: Totally 291 traumatic eardrum perforations with in-/everted edges were included in this study. They were randomly divided into three groups and received conservative treatment, epidermal growth factor (EGF) via Gelfoam patching, or edge-approximation plus Gelfoam patching respectively. Patients in each group were further divided into two subgroups according to the eardrum flap area less than or equal to 1/2 or >1/2 of the perforation size. The healing rate and mean closure time after tympanic membrane perforation were evaluated at three months. RESULTS: Of the total 291 participants, 281 were included in the final statistical analysis. The area of curled edge did not affect the healing outcome significantly in any groups (P>0.05). The healing rate varied slightly: 90.7% vs 92.3% in spontaneous healing group, 98.2% vs 97.4% in EGF via Gelfoam patching group, and 96.5% vs 100% in edge-approximation plus Gelfoam patching group. In addition, in all groups the area of curled edge did not affect the mean closure time significantly (P>0.05). The closure time was (32.3+/-2.4) d vs (30.6+/-3.1) d in sponaneous healing group, (13.4+/-2.5) d vs (13.1+/-1.9) d in EGF via Gelfoam patching group, and (11.9+/-3.1) d vs (12.2+/-2.1) d in edge-approximation plus Gelfoam patching group. CONCLUSION: The eardrum flap area of traumatic eardrum perforation does not significantly affect the clinical outcomes.