Study on the resin-ceramic adhesive bond strength using silane coupling agent treated by hydrolysis catalysts / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the effect of two kinds of silane coupling agent on bond strength of resin-ceramic adhesive.</p><p><b>METHODS</b>Four hundred and thirty-two ceramic samples were divided into 9 groups (48 per group), and in each group the ceramic surface was treated with r-methacryloxypropyletrimethoxysilane (MPTS) (50 g/L) in 99% ethanol (Primer A) and the mixture of hydrochloric acid (0.10 mol/L), phosphoric acid (0.05 mol/L) and acetic acid (0.01 mol/L) in 99% ethanol with the same volume (Primer B). Then the treated ceramic was bonded with resin cement (Link Max). The shear bond strength was tested after 5000 and 10 000 thermo-cycles and standing for 24 h.</p><p><b>RESULTS</b>The highest shear bond strengths [(19.5 ± 3.7) MPa, (15.7 ± 3.0) MPa and (14.6 ± 3.0) MPa] of the specimens were obtained with 0.05 mol/L hydrochloric acid. At acid solution of 0.10 mol/L, the specimens using hydrochloric acid [(10.6 ± 3.5) MPa] and phosphoric acid [(9.5 ± 2.7) MPa] showed remarkably higher strength than that using acetic acid [(6.3 ± 2.5) MPa, P < 0.05] after 10 000 thermo-cycles. When the concentration of acid solution was 0.05 mol/L, the shear bond strength of specimens from hydrochloric acid [(14.6 ± 3.0) MPa] was significantly higher than that using phosphoric acid [(6.3 ± 1.9) MPa] and acetic acid [(4.7 ± 1.8) MPa, P < 0.05]. When the concentration of acid solution reached 0.01 mol/L, the specimens using hydrochloric acid exhibited a dramatically increase in shear strength [(12.7 ± 3.2) MPa] compared with that using phosphoric acid [(2.3 ± 1.2) MPa, P < 0.05] and acetic acid [(1.5 ± 1.2) MPa, P < 0.05].</p><p><b>CONCLUSIONS</b>The maximum adhesive bond strength with highest durability was obtained using hydrochloric acid of 0.05 mol/L hydrolysis catalysts to treat siline couple agent.</p>

Induction of apoptosis in human hepatoma cell line SMMC7721 by Newcastle disease virus HN gene / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms of apoptosis induced in human hepatoma cell line SMMC7721 by plasmid pVHN constructed with Newcastle disease virus (NDV) HN gene.</p><p><b>METHODS</b>Twenty-four h after transfection with liposome-plasmid pVHN complexes in vitro, the mortality rate of SMMC7721 cells was determined by MTT staining and flow cytometry (FCM) with PI staining. The alteration of mitochondrial trans-membrane potential of the cells was detected by FCM with rhodamine 123 staining. Cell genomic DNA was detected by agarose electrophoresis. The activation of caspase-3 was assayed by its substrate color reaction.</p><p><b>RESULTS</b>Significant apoptosis was induced by transfection with plasmid pVHN into the cells for 24 h and the mortality rate was 50.0% (the mortality rate of control group was 5.2%). Genomic DNA was fragmented and mitochondrial trans-membrane potential was decreased, but caspase-3 activity increased.</p><p><b>CONCLUSION</b>Significant apoptosis in SMMC7721 cells can be induced by NDV HN gene. Apoptosis may be resulted from the decrease of mitochondrial trans-membrane potential and activation of Caspase-3.</p>