Effect of cold-light bleaching technique on human permanent teeth enamel surface / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effects of the cold-light bleaching technique on crystals and microstructure of the dental enamel.</p><p><b>METHODS</b>The human premolars extracted for orthodontic reasons were treated by a standard cold-light bleaching procedure. After the treatment, all samples were detected by high resolution micro-area X-ray diffractometer, Fourier transform infrared spectroscope and scanning electron microscope.</p><p><b>RESULTS</b>After the permanent teeth were treated with cold-light bleaching technique, the enamels' crystal dimension, crystallinity decreased and irregular surfaces and shallow disk pits appeared.</p><p><b>CONCLUSION</b>The cold-light bleaching technique could lead to the changes of crystals and microstructure in the surface layer of dental enamel.</p>

Evaluation of microvessel density and vascular endothelial growth factor in colorectal carcinoma with 64-multidetector-row CT perfusion imaging / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluate the correlation of 64-multidetector-row CT (64MDCT) perfusion imaging with microvessel density(MVD) and vascular endothelial growth factor(VEGF) in colorectal carcinoma.</p><p><b>METHODS</b>64MDCT perfusion imaging was performed in 33 patients with pathologically verified colorectal carcinoma. Time-density curves (TDC) were created from the region of interest (ROI) drawn over the tumor, target artery and vein by 64MDCT with perfusion functional software. The individual perfusion maps generated were for blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability-surface area product (PS). MVD and VEGF expression of surgical specimens were examined by immunohistochemical staining with anti-CD34, anti-VEGF monoclonal antibody. MVD and VEGF were compared among the different types of TDC in colorectal carcinoma. The correlation of CT perfusion parameters with MVD and VEGF was also examined.</p><p><b>RESULTS</b>TDC of colorectal carcinoma was divided into five types according to their shapes. MVD in the colorectal carcinoma was 22.61+/-9.01. VEGF staining was found in 25 of 29 tumors (86.2%). The score of VEGF expression was 4.15+/-1.09. No significant differences of MVD and VEGF expression among TDC types were found (F=2.59, 1.11, P>0.05). There were also no correlations of MVD and VEGF expression with any dynamic CT parameters (P>0.05).</p><p><b>CONCLUSION</b>64MDCT perfusion imaging, MVD and VEGF may reflect angiogenic activity, but no significant correlations are found among them.</p>

Polymorphic analysis of two Y chromosome short tandem repeat loci in Chinese Chengdu Han population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To reveal the distribution of genetic polymorphism of two novel Y chromosome short tandem repeat (Y-STR) loci (DYS508, DYS516) in Chinese Chengdu Han population.</p><p><b>METHODS</b>Two Y-STR loci were amplified with PCR. The products of PCR were analyzed with polyacrylamide gel electrophoresis. Each allele of these 2 Y-STR loci was sequenced and the allele ladders were constructed. Alleles of these Y-STR loci were nominated according to recommendations of the International Society of Forensic Genetics (ISFG).</p><p><b>RESULTS</b>Six and 6 alleles were observed in loci DYS508 and DYS516 respectively. The gene diversity of DYS508 and DYS516 was 0.7242 and 0.7931 respectively. The diversity of haplotype for these Y-STR loci was 0.9397. The value of discrimination power and the exclusion chance of paternity for these Y-STR loci were same as the value of haplotype diversity.</p><p><b>CONCLUSION</b>Both Y-STR loci are high genetic polymorphic. They are beneficial to the test of male-female mixtures and paternity identification in forensic science.</p>