Comparative study on the cellular activities of osteoblast-like cells and new bone formation of anorganic bone mineral coated with tetra-cell adhesion molecules and synthetic cell binding peptide

PURPOSE: We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg-Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of betaig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15). METHODS: To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis. RESULTS: Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with Ca2+ deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups. CONCLUSIONS: ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

Non-systemic Vasculitic Neuropathy Presenting as Ascending Paralysis

Typical vasculitic neuropathy commonly manifests as a subacute multiple mononeuropathy, symmetrical or asymmetrical sensori-motor polyneuropathy. Various clinical presentations of peripheral neuropathy may confuse the diagnostic approach sometimes. A 76-year old man presented progressive areflexic ascending paralysis. gait ataxia, severe vibration and position sense impairment for 1 month. We initially considered as subacute demyelinating polyneuropathy. Electrophysiologic studies showed mainly axonopathy with some evidence of demyelination. We performed sural nerve biopsy and diagnosed as vasculitic neuropathy. No laboratory data or clinical findings favored systemic vasculitic involvement. So we concluded vasculitis confined to the peripheral nerves. Vasculitic neuropathy rarely presented as large myelinated nerve fiber disease. It should be considered the clinical variability of vasculitic neuropathy so extensive studies are needed in the case of peripheral polyneuropathy with indefinite cause.