Effects of strontium-modified titanium surfaces on adhesion, migration and proliferation of bone marrow mesenchymal stem cells and expression of bone formation-related genes / 中国组织工程研究

BACKGROUND: Strontium promotes bone formation, and reduces bone resorption. Strontium-modified titanium implant surface has been the focus of research in implant osseointegration under osteoporotic conditions. OBJECTIVE: To investigate the cell adhesion, stretch, and migration of advanced strontium-modified titanium surfaces using bone marrow mesenchymal stem cells isolated from rats. METHODS: Strontium-modified titanium surfaces were produced by sequential treatments with 5 mol/L NaOH, 100 mmol/L strontium acetate, and heated at 600 or 700 °C for 1 hour. After heat treatment, half the samples were soaked in deionized water at 80 °C for 24 hours, then washed and dried. The pure titanium served as control group, and there were five groups. The whole bone marrow adherence method was used to separate bone marrow mesenchymal stem cells from the rats. The modified titanium sheets were placed in 24-well plates and cultured in cell suspension. Cell adhesion and cell proliferation were assessed using cell counting kit-8 assay. After bone marrow mesenchymal stem cells were with the titanium sheet for 24 hours, the actin was stained to observe cell adhesion and stretch. The migration of bone marrow mesenchymal stem cells on different titanium surfaces was investigated using cell scratch test and fluorescence staining. The expression levels of collagen type І, Runx2, osteoprotegerin, RANKL and osteopontin were detected by qRT-PCR. RESULTS AND CONCLUSION: Strontium-modified titanium could promote the stretch and migration of bone marrow mesenchymal stem cells. The number of proliferative cells in the Sr700 group was significantly higher than that in the Sr600 group at 5 days (P < 0.01). On day 14, strontium-modified titanium promoted the expression of collagen type І, Runx2, and osteopontin. In summary, strontium-modified titanium can promote adhesion, spreading, migration and proliferation of rat bone marrow mesenchymal stem cells. Moreover, hydration treatment can enhance the osteogenic activity of rat bone marrow mesenchymal stem cells.

Cellular delivery of modified peptide nucleic acids: a review / 生物工程学报

Peptide nucleic acid (PNA) is a DNA surrogate in which the phosphate deoxyribose backbone of DNA is replaced by repeating N-(2-aminoethyl)glycine units. PNA can hybridize to the complementary DNA and RNA with higher affinity than their oligonucleotide counterparts. This character of PNA not only makes it a new tool for the studies of molecular biology but also the potential candidate for gene-targeting drugs. The non-ionic backbone of PNA leads to stable hybrids with the nucleic acids, but at the same time, the neutral backbone results in poor cellular uptake. To address this problem, studies on modified PNA progress rapidly in recent years. We reviewed literature reports combined with our study about the delivery methods, including backbone modified PNA and PNA-ligand conjugates, and the cellular uptake of modified PNA. In addition, we summarized the problems and future prospect of the cellular delivery of modified PNA.

Vasculogenic mimicry in tongue squamous cell carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the presence of vasculogenic mimicry (VM) in tongue squamous cell carcinoma and explore its clinical significance.</p><p><b>METHODS</b>Forty-two surgical specimens of tongue squamous cell carcinoma were examined for the presence of VM using HE staining and double staining of CD34 and PAS.</p><p><b>RESULTS</b>Of the 42 specimens, 18 (42.86%) showed the presence of VM. VM was not correlated with the patients' age or gender, but with lymph node metastasis and the grade of tumor differentiation. Compared with tumors without VM, the tumors with VM had a significantly higher rate of lymph node metastasis (P<0.05) and a lower grade of differentiation (P<0.05).</p><p><b>CONCLUSION</b>VM can be present in tongue squamous cell carcinoma, and the poorly differentiated tumors contain more VM, which is associated with a greater likeliness of lymph node metastasis and a poorer prognosis.</p>

Discussion on Method Improvement in Checking Minimum Loading Capacity / 中国药房

OBJECTIVE:To improve the old way of examining minimum loading capacity so as to facilitate its operation and make it meet the specific requirements of some special preparations further.METHODS:The minimum loading capacities of ulcer paste,crystal ointment and zinc oxide liniment were examined by specific gravity method,capacity substitution method and capacity addition method.RESULTS:Method for examining minimum loading capacity that failed to be examined before is available now.CONCLUSION:The improved method is reliable and easy to handle.