Assessment of stem cell viability in the initial healing period in rabbits with a cranial bone defect according to the type and form of scaffold

PURPOSE: Increased bone regeneration has been achieved through the use of stem cells in combination with graft material. However, the survival of transplanted stem cells remains a major concern. The purpose of this study was to evaluate the viability of transplanted mesenchymal stem cells (MSCs) at an early time point (24 hours) based on the type and form of the scaffold used, including type I collagen membrane and synthetic bone. METHODS: The stem cells were obtained from the periosteum of the otherwise healthy dental patients. Four symmetrical circular defects measuring 6 mm in diameter were made in New Zealand white rabbits using a trephine drill. The defects were grafted with 1) synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×105 MSCs, 2) collagen membrane and 1×105 MSCs, 3) β-TCP/HA+collagen membrane and 1×105 MSCs, or 4) β-TCP/HA, a chipped collagen membrane and 1×105 MSCs. Cellular viability and the cell migration rate were analyzed. RESULTS: Cells were easily separated from the collagen membrane, but not from synthetic bone. The number of stem cells attached to synthetic bone in groups 1, 3, and 4 seemed to be similar. Cellular viability in group 2 was significantly higher than in the other groups (P0.05). CONCLUSIONS: This study showed that stem cells can be applied when a membrane is used as a scaffold under no or minimal pressure. When space maintenance is needed, stem cells can be loaded onto synthetic bone with a chipped membrane to enhance the survival rate.

A Case of Amnesia Complicated by Poisoning of the Amanita Pantherina

Amanita pantherina and Amanita muscaria have been called hallucinogenic fungi. They contain ibotenic acid and muscimol. Patients may appear to be intoxicated or have apparent 'patherina-muscaria' syndrome, which is atropine-like, but fatality is rare. Confusion, dizziness, tiredness, visual and auditory hypersensitivity, space distortion, unawareness of time, dryness of the mouth, mydriasis and hallucination may occur. Also, in exceptionally rare severe poisoning cases, convulsion, coma and death may occur. A 50-year-old well-nourished and developed man was admitted to this hospital with a 30-minute history of semicoma and involuntary contraction of the extremities which had developed following mushroom ingestion 2 hours earlier. Ingested mushrooms were revealed to be A. pantherina by a mycologist. The patient recovered 7 hours later after only supportive management, but the next day he couldn't recalled any of his hospital duration from admission to 20 hours later. Only a few reports have precise descriptions of the subspecies of the genus and there was no reports on poisoning by A. pantherina in Korea. In addition, there are no reports of amnesia following poisoning by A. pantherina. For these reasons, we report this case, together with a review of the literature.