Infant ectopic cervical thymus in submandibular region

Sporadic cases have been reported of ectopic thymic tissue formed along the path of embryologic descent from the mandibular region to the mediastinum, usually manifesting as an asymptomatic mass. Here is reported the case of an 8-month-old boy with a tender palpable mass in the right upper lateral neck. Preoperative posteroanterior chest radiograph revealed normal structures in the mediastinum superior including the thymus. Magnetic resonance imaging showed a 4-cm x 4-cm soft-tissue mass in the left submandibular region. Surgical resection was performed and histopathologic examination showed that the mass was composed of thymic lymphoid tissue and epithelial cells. Immunohistochemical features included positive expression of LCA, CKpan, EMA, CD20 and CD43 antibodies. The clinical 14-month follow up was negative and the child was growing normally after operation. Ectopic thymus in the submandibular region is uncommon; surgical treatment is the definitive means of pathological diagnosis. Prior to surgery, the presence of a mediastinal thymus should be confirmed to prevent the risk of a total thymectomy.     

舌大小与开He相关性的研究

目的 研究舌大小与开He之间的关系。方法 采用B型超声成像方法分别测量正常He与开He患者的舌大小，通过牙He与正常He舌大小的比较，研究舌大小与开He的相关性。结果 开He患者的舌大小测量结果均值大于正常He者，而且这种差别有显著的统计学意义。结论 与正常He者比较，开He患者存在舌过大的特性。     

激光焊接间距对牙科铸造纯钛性能影响的实验研究

目的:研究激光焊接铸造纯钛时不同的焊接间距对纯钛性能的影响。方法:将铸造钛试样按照焊接间距的大小分为4组:0.00、0.25、0.50、1.00mm组,肉眼、扫描电镜观察焊缝区外观,测试焊件的抗拉强度,整铸件为对照组。结果:各试验组焊缝区显示全层焊透、无明显气孔等焊接缺陷,断口电镜显示为延展性(韧窝)与脆性(气孔、裂纹)共存的形貌。各实验组与对照组间抗拉强度方差分析结果显示差异无显著性(P>0.05)。结论:不同的焊接间距对铸钛的机械性能无明显影响。     

Leiomyomatous hamartoma of the midline maxillary gingival presenting as a congenital epulis: a case report with an immunohistochemical study

An otherwise-healthy 2-year-old Japanese female presented with a polyp-like lesion on the palatal surface at the incisive papilla. The appearance of the lesion was similar to that of a congenital epulis. The histological findings showed proliferating mesenchymal components that contained mainly smooth muscle admixed with collagen fibres, nerve fibres, small vessels and mucous salivary glands. The immunohistochemical staining findings for α-smooth-muscle actin, desmin and S-100 protein were all positive. The histological diagnosis was therefore leiomyomatous hamartoma, based on clinical microscopic observations.     

头颈部肿瘤的基因治疗研究进展

基因治疗恶性肿瘤已从实验室走向临床试用阶段。目前国际上已批准的基因治疗方案１３０余项，其中７０％的方案是肿瘤基因治疗。头颈部肿瘤相对表浅、直观，且有区域淋巴结转移的特性，这为基因治疗的应用提供了天然的条件。近年文献报道由腺病毒介导的自杀基因治疗动物肿瘤模型的实验研究，为临床基因治疗头颈癌展示良好的应用前景。虽然人们已克隆出多种可用于肿瘤基因治疗的基因，但尚未找到一种临床应用后抗肿瘤效果非常显著的治疗性目的基因。这将有待于通过相关的研究，以期实现人类基因组研究计划发现和鉴定     

Attachment of gold nanoparticles to glassy carbon electrode and its application for the voltammetric resolution of ascorbic acid and dopamine

Gold nanoparticles have been attached on glassy carbon electrode surface through sulfhydryl-terminated monolayer and the gold nanoparticles-immobilized glassy carbon electrodes have been applied to the electrocatalytic oxidation of ascorbic acid, reducing the overpotential by about 200 mV with obviously increased current response. Due to its strong electrocatalytic activity towards ascorbic acid, the gold nanoparticles modified electrode can resolve the overlapped voltammetric waves of ascorbic acid and dopamine into two well-defined voltammetric peaks with peak-to-peak separation in potentials of about 300 mV. This can be used to allow the selective determination of ascorbic acid in the presence of dopamine. The catalytic current obtained from differential pulse voltammetry is linearly dependent on ascorbic acid concentration over the range of 6.5 × 10^?6 to 1.45 × 10^?4 M with correlation coefficient of 0.998 in the presence of dopamine. The detection limit (3σ) for AA was found to be 2.8 × 10^?6 M. The simultaneous determination of ascorbic acid and dopamine in their binary mixture has also been investigated. The modified electrode shows good selectivity, stability and anti-fouling properties. The proposed methods have been used for the selective determination of ascorbic acid in the presence of dopamine and for the simultaneous determination of both them in their mixtures with satisfactory results.     

VDR deficiency affects alveolar bone and cementum apposition in mice

Objective

To compare the mineralisation density (MD), morphology and histology of alveolar bone and cementum amongst VDR +/+, VDR −/−, and VDR −/− groups supplemented with a diet TD 96348, containing 20% lactose, 2.0% calcium and 1.25% phosphorous.

Methods

Four groups of mice (6 mice/group) were identified by genotyping: VDR +/+ mice (VDR wild type), VDR −/− mice (VDR deficient), VDR −/− offsprings derived from VDR −/− parents receiving a supplemental diet (early rescued), and VDR −/− mice fed with a supplemental diet beginning at age one month (late rescued). All mice were sacrificed at age 70.5 days. Micro-CT was used to compare MD and morphology of alveolar bone and cementum. H–E and Toluidine blue staining was used to examine the ultrastructure of the alveolar bone and cementum at matched locations.

Results

In VDR −/− group, alveolar bone and cementum failed to mineralise normally. Early rescue increased MD of alveolar bone in VDR −/− mice with excessive alveolar bone formation, but which not observed in late rescue group. MD and morphology of cementum–dentine complex in both early and late rescue groups were comparable with VDR +/+ group when feeding with high-calcium rescue diet.

Conclusions

VDR affects alveolar bone mineralisation and formation systemically and locally. However, cementum apposition and mineralisation is mainly regulated by calcium concentrations in serum.     

IFN-γ enhances the anti-tumour immune response of dendritic cells against oral squamous cell carcinoma

Objective

To investigate the expression of antigen processing-1 (Tap-1) and Tapasin in oral squamous cell carcinoma (OSCC), and observe the immune response against OSCC by use of IFN-γ-antigen induced dendritic cells (DCs) in vitro and in vivo.

Design

Expression of Tap-1 and Tapasin in different cell lines was analysed. CAL27 cells were treated with IFN-γ. Antigen from the treated cells was presented by DCs. Pulsed DC was then co-cultivated with CD8+ T lymphocyte to induce antigen specific cytotoxic lymphocytes (CTLs). The immune response elicited by CTLs against OSCC was observed.

Results

A significant lower expression of Tap-1 and Tapasin was observed in OSCC cell lines. IFN-γ exerted time-dependent effect for increasing the expression of these genes. Antigen from the treated CAL27 cells was presented by DCs. CTLs were induced and generated a strong immune response in vitro and in vivo.

Conclusions

Tap-1 and Tapasin were downregulated in OSCC. IFN-γ increased the expression of these genes. Use of IFN-γ-antigen induced DCs could induce stronger immune response in vitro and in vivo.     

Monitoring bacterial-demineralization of human dentine by electrochemical impedance spectroscopy

Objective

The purpose of this study was two-fold: (1) to monitor bacterial biofilm formation and bacteria-induced demineralization of dentine in situ by using electrochemical impedance spectrum (EIS); (2) to examine the relationship between EIS findings and changes in the chemical composition and ultrastructure of dentine during bacteria-induced demineralization.

Methods

In this study, dentine demineralization was induced by Streptococcusmutans (ATCC 25175) in the presence of sucrose in culture medium and was monitored using two EIS measurement systems (Type A with a working electrode and Type B without a working electrode). Scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to examine the morphology, element contents and crystallinity of hydroxyapatite (HAP) on the dentine surface. Transverse microradiography (TMR) was used to characterize the lesion depth and degree of mineral loss during demineralization.

Results

The resistance of the bulk dentine (R_d) and the apparent resistance of dentine (R_a) measured from the Type A and Type B EIS systems, respectively, decreased gradually with demineralization. The resistance of the biofilm formed on dentine surface was determined by fitting the EIS data with equivalent circuits. The presence of biofilm slightly increased R_a of dentine before demineralization. However, the electrochemical behavior of biofilm did not affect the decreasing impedance of dentine with demineralization. The SEM, EDX, XRD and TMR results demonstrated that the surface and bulk dentine gradually became more porous due to the loss of minerals during demineralization, which in turn resulted in the decrease in R_d and R_a values obtained from EIS systems.

Conclusions

This investigation highlighted EIS as a potential technique to monitor biofilm formation and bacterial-induced demineralization in situ.     

Influence of powder/liquid mixing ratio on porosity and translucency of dental porcelains

STATEMENT OF PROBLEM: Dental technicians use a variety of techniques when condensing dental porcelains. It is unclear whether these techniques affect the total porosity and translucency of dental porcelains. PURPOSE: The objective of this study was to determine whether varying the powder/liquid ratio during condensation affects porosity and translucency of porcelains.Material and methods Duceram LFC dentin, Duceram LFC incisal, IPS Eris dentin, and IPS Eris incisal porcelains were studied. For each specimen, 1.0 g of porcelain powder was mixed with 1 of 3 different volumes of deionized water to form a slurry with a thin, medium, or thick consistency. The slurries were condensed in a plastic syringe mold, fired, and polished to a 3-microm finish to form 12 groups of 4 specimens each (14-mm diameter, 1.10-mm thickness). The apparent density (g/mL) of each specimen was measured using Archimedes method, and the porosity (%) calculated. Each specimen was coupled to standard ceramic tiles using an immersion liquid, and the color shade was measured in CIE Yxy coordinates using a tristimulus colorimeter. Translucency was assessed by calculating the contrast ratio of shade value (Y) in front of black versus white backgrounds. Two-way analysis of variance and Tukey's multiple comparison tests (alpha = .05) were used to test for significant effects of factors. RESULTS: Porcelain type and powder/liquid ratio had a significant interactive effect on the apparent density (P < .001) and on total porosity (P = .003); however, there was no consistent trend. The powder/liquid ratio did not significantly affect translucency (P = .28), but porcelain type had a significant effect on translucency (P < .001). CONCLUSION: In this in vitro study, total porosity of specimens prepared using 4 porcelains was found to be sensitive to powder/liquid ratio; whereas translucency was found to be insensitive to powder/liquid ratio.