Is it enough to observe less than 2 cm sized gastric SET?

BACKGROUND AND AIMS: The recent surge in demand for screening endoscopy has led to an increased detection of gastric subepithelial tumors (SETs). According to current guideline, SETs less than 2 cm in size are recommended for periodic surveillance. In light of recent advancement in therapeutic endoscopy in resection of small SET, we analyzed the histopathological features and the effectiveness of endoscopic resection for these small SETs. METHODS: Retrospectively study was performed on 74 patients who underwent endoscopic resection of gastric small (≤ 2 cm) upper gastrointestinal tract SETs. The outcomes including histopathology and en bloc resection were analyzed. RESULTS: The mean SET size was 11.69 ± 5.11 mm. The mean procedure time was 81.26 ± 42.53 min. Of the 74 patients, 28 patients had leiomyomas, 26 had gastrointestinal stromal tumors (GISTs), 14 had ectopic pancreas, 4 had lipomas, and 2 had neuroendocrine tumors. Among those with GIST, two patients exhibited high-risk histology. All patients underwent successful and uneventful endoscopy. CONCLUSIONS: Endoscopic resection can be recommended even for the small gastric SETs. In our study, we found that SETs with a size of less than 2 cm have significant proportion of GISTs which harbor malignant transformation potential.

Rapid neural differentiation of human cord blood-derived mesenchymal stem cells.

Human umbilical cord blood (UCB) contains hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs), both of which are regarded as valuable sources for cell transplantation and cell therapy. Adherent cells expressing MSCs-related antigens such as SH2, CD13, CD29, and ASMA, have been isolated from a mononuclear cell fraction of human UCB. Under proneurogenic conditions, these UCB-derived adherent cells rapidly assumed the morphology of multipolar neurons. Both immunofluorescence and RT-PCR analyses indicated that the expression of a number of neural markers including Tuj1, TrkA, GFAP and CNPases, was markedly elevated during this acute differentiation. The neurogenic potential of UCB-derived may facilitate stem cell therapeutic approaches to neurodegenerative diseases.

In vitro mesengenic potential of human umbilical cord blood-derived mesenchymal stem cells.

Human mesenchymal stem cells (hMSCs) have been paid a great deal of attention because of their unprecedented therapeutic merits endowed by powerful ex vivo expansion and multilineage differentiation potential. Umbilical cord blood (UCB) is a convenient but not fully proven source for hMSCs, and hence, greater experience is required to establish UCB as a reliable source of hMSCs. To this end, we attempted to isolate hMSC-like adherent cells from human UCB. The isolated cells were highly proliferative and exhibited an immunophenotype of CD13+ CD14- CD29+ CD31- CD34- CD44+ CD45- CD49e+ CD54+ CD90+ CD106- ASMA+ SH2+ SH3+ HLA-ABC+ HLA-DR-. More importantly, these cells, under appropriate conditions, could differentiate into a variety of mesenchymal lineage cells such as osteoblasts, chondrocytes, adipocytes, and skeletal myoblasts. This mesengenic potential assures that the UCB-derived cells are multipotent hMSCs and further implicates that UCB can be a legitimate source of hMSCs.

Skeletal myogenic differentiation of mesenchymal stem cells isolated from human umbilical cord blood.

Human umbilical cord blood (UCB) has been regarded as an alternative source for cell transplantation and cell therapy because of its hematopoietic and nonhematopoietic (mesenchymal) potential. Although there has been debate about whether mesenchymal stem cells (MSCs) are invariably present in UCB, several reports showed that MSC-like cells could be consistently derived from human UCB and, moreover, could differentiate into various cells of a mesodermal origin. However, it remains unclear whether these UCB-derived MSCs are also capable of differentiating into skeletal muscle cells. In this study, we isolated MSCs from human UCB and induced them to differentiate into skeletal muscle cells. During cell culture expansion, UCB-derived mononuclear cells gave rise to adherent layers of fibroblast-like cells expressing MSC-related antigens such as SH2, SH3, alpha-smooth muscle actin, CD13, CD29, and CD49e. More important, when these UCB-derived MSCs were incubated in promyogenic conditions for up to 6 weeks, they expressed myogenic markers in accordance with myogenic differentiation pattern. Both flow cytometric and reverse transcriptase-polymerase reaction analyses showed that two early myogenic markers, MyoD and myogenin, were expressed after 3 days of incubation but not after 2 weeks. At week 6, more than half of UCB-derived MSCs expressed myosin heavy chain, a late myogenic marker. Our results demonstrate that UCB-derived MSCs possess a potential of skeletal myogenic differentiation and also imply that these cells could be a suitable source for skeletal muscle repair and a useful tool of muscle-related tissue engineering.