Heterogeneity of Osteosarcoma Cell Lines Led to Variable Responses in Reprogramming

Four osteosarcoma cell lines, Saos-2, MG-63, G-292 and U-2 OS, were reprogrammed to pluripotent state using Yamanaka factors retroviral transduction method. Embryonic stem cell (ESC)-like clusters started to appear between 15 to 20 days post transduction. Morphology of the colonies resembled that of ESC colonies with defined border and tightly-packed cells. The reprogrammed sarcomas expressed alkaline phosphatase and pluripotency markers, OCT4, SSEA4, TRA-1-60 and TRA-1-81, as in ESC up to Passage 15. All reprogrammed sarcomas could form embryoid body-like spheres when cultured in suspension in a low attachment dish for up to 10 days. Further testing on the directed differentiation capacity of the reprogrammed sarcomas showed all four reprogrammed sarcoma lines could differentiate into adipocytes while reprogrammed Saos-2-REP, MG-63-REP and G-292-REP could differentiate into osteocytes. Among the 4 osteosarcoma cell lines, U-2 OS reported the highest transduction efficiency but recorded the lowest reprogramming stability under long term culture. Thus, there may be intrinsic differences governing the variable responses of osteosarcoma cell lines towards reprogramming and long term culture effect of the reprogrammed cells. This is a first report to associate intrinsic factors in different osteosarcoma cell lines with variable reprogramming responses and effects on the reprogrammed cells after prolonged culture.     

Hearing impairment and hearing aid usage in Singapore

Objective: To examine the epidemiological and audiological profile, pattern of hearing aid (HA) fitting and usage among HA users in Singapore. Design: Retrospective cross-sectional study. Study sample: Cohort of 1068 subjects issued with HAs at a tertiary hospital between 2001 and 2013. Results: Mean age was 70?years with 50.8% male. Mean hearing loss (HL) was 63.1?dB and 69.5% had at least moderate-severe HL. Sensorineural HL was present in 66.4% and 69.8% had symmetrical HL. “Behind-the-Ear” HAs were cheaper than “In-Ear” HAs. Standard “Behind-The-Ear” HAs were also cheaper than “Receiver-in-Canal” HAs. Among In-Ear HAs, “In-the-Canal” and “Completely-in-Canal” were more popular than “In-the-Ear” HAs despite costing more. HA was used ≥4?days/week by 85.6% but >7?h per day by only 35.7%. Only 18% received bilateral first HA fitting. In multivariate analysis, younger age and symmetrical HL were predictors of bilateral HA uptake while better Pure-Tone-Audiometry of aided ear and >7?h of daily HA usage were predictors of successive HA fitting. Conclusions: HA users in Singapore were elderly and presented with advanced HL. Bilateral HA adoption and average daily use were low compared to other developed countries. Future research on understanding the suboptimal HA usage should explore patients' motivation, hearing disability, and HA effectiveness.     

Flow-diverter in radiation-induced skull base carotid blowout syndrome: do not write it off!

Post-radiotherapy carotid blowout syndrome (CBS) of the skull base is a rare but often catastrophic complication of head and neck malignancies. The existing literature on the treatment of this condition with flow-diverting devices (FDD) is extremely limited and disappointing. We present a case of impending CBS in a patient previously irradiated for nasopharyngeal cancer that was successfully treated with use of multiple FDDs, adjunctive endonasal packing and delayed reinforcement with pedicled naso-septal flap, yielding an excellent outcome at 14-months follow-up. Notwithstanding the discouraging results in literature, our anecdotal experience suggests that endovascular reconstruction using FDD could be an option with long-term viability in post-radiotherapy CBS involving the skull base when reinforced with a vascularised naso-septal flap.