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In bone marrow transplantation (BMT), bone marrow cells (BMCs) have traditionally been injected intravenously. However, remarkable advantages of BMT via the intrabone-marrow (IBM) route (IBM-BMT) over the intravenous route (IV-BMT) have been recently documented by several laboratories. To clarify the mechanisms underlying these advantages, we analyzed the kinetics of hemopoietic regeneration after IBM-BMT or IV-BMT in normal strains of mice. At the site of the direct injection of BMCs, significantly higher numbers of donor-derived cells in total and of c-kit ؉ cells were observed at 2 through 6 days after IBM-BMT. In parallel, significantly higher numbers of colony-forming units in spleen were obtained from the site of BMC injection. During this early period, higher accumulations of both hemopoietic cells and stromal cells were observed at the site of BMC injection by the IBM-BMT route. The production of chemotactic factors, which can promote the migration of a BM stromal cell line, was observed in BMCs obtained from irradiated mice as early as 4 hours after irradiation, and the production lasted for at least 4 days. In contrast, sera collected from the irradiated mice showed no chemotactic activity, indicating that donor BM stromal cells that entered systemic circulation cannot home effectively into recipient bone cavity. These results strongly suggest that the concomitant regeneration of microenvironmental and hemopoietic compartments in the marrow (direct interaction between them at the site of injection) contributes to the advantages of IBM-BMT over IV-BMT. STEM CELLS

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BackgroundConfocal laser endomicroscopy (CLE) can provide in vivo subcellular resolution images of esophageal lesions. However, the learning curve in interpreting CLE images of precancerous or early-stage esophageal squamous cancer is unknown. The goal of this study is to evaluate the diagnostic accuracy and inter-observer agreement for differentiating esophageal lesions in CLE images among experienced and inexperienced observers and to assess the learning curve.MethodAfter a short training, 8 experienced and 14 inexperienced endoscopists evaluated in sequence 4 sets of high-quality CLE images. Their diagnoses were corrected and discussed after each set. For each image, the diagnostic results, confidence in diagnosis, quality and time to evaluate were recorded.ResultsOverall, diagnostic accuracy was greater for the second, third, fourth set of images as compared with the initial set (odds ratio [OR] 2.01, 95% CI 1.22–3.31; 7.95, 3.74–16.87; and 6.45, 3.14–13.27), respectively, with no difference between the third and fourth sets in accuracy (p = 0.67). Previous experience affected the diagnostic accuracy only in the first set of images (OR 3.70, 1.87–7.29, p<0.001). Inter-observer agreement was higher for experienced than inexperienced endoscopists (0.732 vs. 0.666, p<0.01)ConclusionCLE is a promising technology that can be quickly learned after a short training period; previous experience is associated with diagnostic accuracy only at the initial stage of learning.

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Abstract. The ability of tumor cells to autonomously generate tumor vessels has received considerable attention in recent years. However, the degree of autonomy is relative. Meanwhile, the effect of bone marrow-derived mesenchymal stem cells (BMSCs) on tumor neovascularization has not been fully elucidated. The present study aimed to illuminate whether cell fusion between glioma stem cells and BMSC is involved in glioma neovascularization. BMSCs were isolated from transgenic nude mice, of which all nucleated cells express green fluorescent protein (GFP). The immunophenotype and multilineage differentiation potential of BMSC were confirmed. SU3 glioma stem/progenitor cells were transfected with red fluorescent protein (SU3-RFP cells). In a co-culture system of BMSC-GFP and SU3-RFP, RFP + /GFP + cells were detected and isolated by dual colors using FACS. The angiogenic effect of RFP + /GFP + cells was determined in vivo and in vitro. Flow cytometry analysis showed that BMSC expressed high levels of CD105, C44, and very low levels of CD45 and CD11b. When co-cultured with SU3-RFP, 73.8% of cells co-expressing RFP and GFP were identified as fused cells in the 5th generation. The fused cells exhibited tube formation ability in vitro and could give rise to a solid tumor and form tumor blood vessels in vivo. In the dual-color orthotopic model of transplantable xenograft glioma, yellow vessel-like structures that expressed CD105, RFP and GFP were identified as de novo-formed vessels derived from the fused cells. The yellow vessels observed in the tumor-bearing mice directly arose from the fusion of BMSCs and SU3-RFP cells. Thus, cell fusion is one of the driving factors for tumor neovascularization.