Primo Vascular System: An Endothelial-to-Mesenchymal Potential Transitional Tissue Involved in Gastric Cancer Metastasis.

Gastric cancer is the fourth commonest cancer in the world and the second leading cause of cancer-related death. Investigation of gastric cancer metastasis is one of the hottest and major focuses in cancer research. Growing evidence manifested that primo vascular system (PVS) is a new kind of circulatory system beyond vascular and lymphatic system. Previous researches revealed that PVS is a specific tissue between endothelium and mesenchyme and is involved in cancer, especially in tumor metastasis and regeneration. In current study, we investigated the role of primo vessels in gastric cancer metastasis and its possible relationship to vascular vessels formation. Our results indicated that primo vessels were involved in gastric cancer metastasis. We observed blood vessel-mediated metastasis, primo vessel-mediated metastasis, and an intermediate state between them. We deduced that primo vessels may be precursors of blood vessels. These results possibly provided a thoroughly new theoretic development in cancer metastasis.

Mechanical and physicochemical properties of xenogeneic bone scaffold materials A comparative study / 中国组织工程研究

BACKGROUND: The core of bone tissue engineering is to construct a scaffold that is similar to human bone tissue structure and features.OBJECTIVE: To compare pathochemical and mechanical characteristics between pig and human bone scaffold materials.DESIGN, TIME AND SETTING: Contrast study was performed at Clinical Anatomy Institute, South Medical University; Guangdong Province Key Laboratory of Tissue Construction and Detection from March to December 2006.MATERIALS: Four fresh health adult human cadavers were provided by South Medical University, Guangzhou Red Cross Society, and the relatives knew the fact. Ultra low temperature freezing 6-month iliac bones of 6 adult swines were also used in this study.METHODS: Pig iliac and healthy adults iliac bones were obtained to remove soft tissue, curettage periosteum and bone marrow. Bone sawing machine was used to cut cancellous bone into smaller bone sections around 5 mm×5 mm×40 mm, which underwent ultrasonic cleaning, H2O2 and alcohol soaking, freeze drying and radiation treatment; finally, xenogeneic bone scaffold and allogeneic bone scaffold were obtained.MAIN OUTCOME MEASURES: Xenogeneic bone scaffold material and human allograft bone scaffold were observed with scanning electron microscopy to compare porosity, contents of protein content, calcium and phosphorus, and mechanical properties.RESULTS: Xenogeneic bone scaffold and allogeneic bone scaffold both had intrinsical bone trabecula, trabecular spaces and bone cavity system. Both of them had unabridged natural three dimensional network structure. The 3D supporting frames of them were complete. The xenogeneic bone scaffold had more spaces than allogeneic bone scaffold. The size of both scaffolds was approximation, about 400 μm. The interval porosity of xenogeneic bone scaffold was higher than the allogeneic bone scaffold (P<0.05). And the protein of xenogeneic bone scaffold was not as many as it of allogeneic bone scaffold (P<0.05). The contents of Ca and P were similar (P>0.05), and there was no significant difference in Young's modulus of xenogeneic bone scaffold and allogeneic bone scaffold (P>0.05).CONCLUSION: Xenogeneic bone scaffold may completely meet the clinical demands for bone grafting or be the scaffold of bone tissue engineering in mechanical chemical properties.