Medicina oral, patologia oral y cirugia bucal 01/2012; DOI:10.4317/medoral.17643600 · 1.17 Impact Factor
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ABSTRACT: Our laboratory has used bone-forming cartilage from embryonic mouse limb bud cells differentiated in a rotating bioreactor to heal defects created in the skulls of mice. However, these rounded nodules fit poorly in the defect. Consequently, methods of producing a flat piece of cartilage, better suited for skull implants, were explored. In the current experiments, bone marrow mesenchymal stem cells were differentiated into cartilage on Silastic gas exchange membranes (bubbles) developed as a hardware component for spaceflight (IML-2; 1992). Objective: To differentiate bone marrow stem cells on the membrane, producing a flat piece of cartilage. Methods: Isolated bone marrow cells from adult C57-Bl or 7-9 day old CD-1 mice were expanded in culture. After 2 passages, cells suspended in medium were inoculated onto membranes in hardware casings or in assembled hardware units. Cultures were placed in Petri dishes and incubated at 37C with or without 5% CO2 for two hours; 5% CO2 was used thereafter. After medium addition, cells were cultured for 3-7 days with the medium changed every other day, then fixed. Results: Cells with no CO2 during the first two hours of incubation formed small aggregates and occasional larger (0.5mm) ones. Aggregates stained with alcian blue at low pH and metachromatically with Toluidine blue, indicating cartilage matrix production. Cells receiving initial CO2 spread on the membrane, developing numerous extended processes and a neuronal appearance. Methylene blue staining revealed Nissl bodies in the cytoplasm of neuronal-like cells. Conclusion: The initial gas environment coupled with the Silastic substrate influenced cellular differentiation, but the desired shape was realized only on membranes in casings, not in assembled hardware. In future studies, a commercially available Silastic membrane (Flexcell) will be used to produce a larger piece of tissue.
Support: UT Health Biotechnology Office and Medical School Summer Research Program, UTDB Startup Funds.
IADR General Session 2011; 03/2011
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ABSTRACT: We studied the outcome and prognostic factors for T1 rectal cancer patients undergoing standard resection or transanal excision.
One hundred and twenty-four patients with T1 rectal cancer were included in the study, of whom 66 (53.2%) underwent standard resection and 58 (46.8%) underwent transanal excision. Survival analysis was performed to compare the outcome.
The 5-year local recurrence rate was 11.0% in the transanal excision group versus 1.6% in the standard resection group (P = 0.031) but the 5-year disease-free survival and overall survival rates were not significantly different between the two groups. Multivariate analysis suggested that a high tumour grade and perineural or lymphovascular invasion were independent risk factors for local recurrence and recurrence-free survival. For high-risk patients (with at least one of the above risk factors), the 5-year local recurrence and 10-year recurrence-free survival rates were 21.2% and 74.5%, versus 1.2% and 92.0% in low-risk patients (P = 0.00003 and P = 0.003). In patients undergoing transanal excision, none in the low-risk group had local recurrence during follow up, while 40% (6 of 15) of patients in the high-risk group developed local recurrence within 5 years after surgery. The 5-year local recurrence rate was 45.0%.
Transanal excision in T1 rectal cancer may result in a high rate of local failure for patients with a high-grade tumour, or perineural or lymphovascular invasion. Local excision should be avoided as a curative treatment in high-risk patients.
Colorectal Disease 02/2011; 13(2):e14-9. DOI:10.1111/j.1463-1318.2010.02424.x · 2.35 Impact Factor