The adoption of new endodontic technology amongst Danish general dental practitioners

AIM: To assess the adoption of new endodontic technology in a population of Danish practitioners. METHODOLOGY: Members of the Copenhagen Dental Association (n = 1156) were approached with a questionnaire concerning the frequency of various endodontic procedures. Three options were available: often, occasionally and never. Responses were anonymous. The statistical analyses were performed as studies of association in two- or three-way contingency tables, and with Goodman-Kruskal's gamma-coefficient as the basic tool chosen. RESULTS: Only data from general practitioners (GPs) in private practice were analysed (n = 956). The response rate was 72%. NiTi hand instruments were often used to negotiate canals by 18%, whilst 10% often used NiTi rotary systems. Electronic apex locators were often employed by 15%. Nineteen per cent reported that warm gutta-percha was often used. A majority (53%) often spend two sessions to instrument a molar, and 20% often needed three or more sessions to finish the shaping phase. To complete a treatment of a nonvital case most practitioners reported to use at least three appointments. Only 4% frequently applied rubber dam. CONCLUSIONS: The adoption of new endodontic technology is at an early stage amongst Danish GPs. A new revised remuneration system might influence the rate of adoption, allowing the practitioners to act more rationally and produce a higher frequency of good-quality root fillings. Progress towards high quality endodontics might be hindered by the nonuse of rubber dam.     

经颞浅动脉灌注氟尿嘧啶和卡铂治疗舌癌

目的探讨术前联合应用氟尿嘧啶、卡铂诱导化疗治疗舌癌的临床效果。方法20例舌癌患者经颞浅动脉插管连续顺序灌注氟尿嘧啶和卡铂,比较化疗前、后原发肿瘤灶的大小,并记录化疗的主要不良反应。结果完全缓解(CR)18例(90%),部分缓解(PR)2例(10%),总有效率(CR+PR)100%;不良反应轻微。结论经颞浅动脉插管灌注氟尿嘧啶和卡铂是治疗舌癌的一种有效方法,不良反应发生率低且轻。     

口腔细菌终末代谢酸的反相梯度高效液相色谱法分析条件研究

目的:探讨测定口腔细菌终末代谢酸的反相梯度高效液相色谱法最佳分析条件。方法:采用高效液相色谱技术梯度洗脱程序,流速110~210 mlPmin,检测波长217 nm,流动相为60% 012 molPL磷酸盐甲醇溶液pH218,对常见的细菌终末代谢酸进行不同培养基、pH值、温度、萃取液、沉淀剂等分析条件进行研究。结果:口腔细菌在牛心脑浸液(BHI)培养液中经48 h厌氧培养,上清液在pH 117的酸度下用乙醚提取可得到理想的色谱分析结果。结论:该方法可推广应用于细菌终末代谢酸鉴定。     

Selective transfer of Ag+ at the water|1,2-dichloroethane interface facilitated by complex formation with a calixarene derivative

The facilitated transfer of silver, Ag⁺, has been studied at the Interface between Two Immiscible Electrolyte Solutions (ITIES). The transfer was achieved with the assistance of a calixarene-based silver ionophore. An investigation of the mechanistic details of the transfer was conducted using cyclic voltammetry at both micro and macro liquid|liquid interfaces. The mechanism was found to follow a Transfer by Interfacial Complexation (TIC)/Transfer by Organic phase Complexation (TOC) mechanism. The complex stoichiometry was found to shift from 1:1 to 1:2, metal:ligand, with increasing ionophore concentration. The logarithms of the complex association constants, $\log {\beta }_1^{\mathrm{o}}\mathrm{and}\log {\beta }_2^{\mathrm{o}}$, were estimated at 12.4 and 14.5, respectively. The charge transfer current was also found to be limited by diffusion of the transferring species and was unchanged by the presence of a range of interferents. The system thus shows promise for selective analytical applications.     

Levels of gingival tissue platelet activating factor after conventional and regenerative periodontal surgery

The hypothesis, a relationship between gingival tissue platelet activating factor (PAF) levels and healing after periodontal surgery, was tested by measuring PAF levels in gingival tissues collected from sites that had undergone flap surgery and guided tissue regeneration (GTR) or flap surgery alone. Using a split-mouth design, 20 intrabony defects were randomly assigned to treatment with flap surgery and GTR (group 1) or with flap surgery alone (group 2). Gingival tissue samples were obtained at surgery (baseline) and at 6-month follow-up evaluation visit. One half of each sample was used for analysis of PAF levels by high-performance liquid chromatography, and the other half of the sample was used for histomorphometric analysis that included measurements of number and diameter of blood vessels. PAF levels and diameter of blood vessels were significantly decreased (p < 0.01), and the number of blood vessels was significantly increased (p < 0.05) in both groups after 6 months compared to the baseline values. Postoperative number of blood vessels were significantly higher in group 1 (p < 0.05), whereas there was no significant difference in postoperative PAF levels between the two groups (p > 0.05). Based on the reported results, it is suggested that a decrease in gingival PAF levels might be found after conventional and regenerative periodontal surgery.     

DSA介入狗舌动脉5-Fu和CBP灌注+栓塞术的实验研究

目的:研究经数字减影血管造影术(DSA)介入舌动脉灌注及静脉注射抗癌药物后,血和局部组织中药物浓度,以及肝肾功能、血相变化,为临床介入治疗提供实验依据.方法:将5只狗分为3组,第一组A、B 2只狗,第二组C、D 2只狗,第三组E 1只狗,经股动脉DSA介入舌动脉灌注5-Fu、卡铂各75mg,明胶海绵栓塞;另一组静脉注射等量5-Fu与卡铂,于10min、20min、30min至5天,检查舌、颊组织及血中药物浓度、肝肾功能、血常规,6周后处死,行舌动脉病理检查.结果:DSA介入舌动脉药物灌注 栓塞术后10min、20min、30min舌组织中药物含量是静脉注射药物的25、20、4倍,30min后血中药物浓度两组之间无显著性差异.肝肾功能、血常规两组差别不大,舌动脉经灌注后其内膜不完整,平滑肌细胞较多空泡样变.结论:DSA动脉介入灌注栓塞,可增加局部组织中抗癌药物浓度,提高药物的抗瘤性,对提高治疗效果有一定作用.     

Saliva electrophoretic protein profiles in infants: changes with age and impact of teeth eruption and diet transition

Objective

The objective of this study was to describe the changes in salivary protein profiles in infants between the ages of 3 and 6 months, and to evaluate the impact of teeth eruption and introduction of solid foods on such profiles.

Design

73 infants were followed longitudinally at 3 and 6 months of age. Their whole saliva proteins were separated by SDS–PAGE electrophoresis and semi-quantified by image analysis. Amylase activity was also measured on a sub-sample of the population (n = 42 infants). Bands which abundance was significantly different between the two ages according to paired comparisons were identified by mass spectrometry techniques.

Results

Out of 21 bands, 13 were significantly different between 3 and 6 months of age. Two short variants of amylase increased in abundance with age, as did amylase activity. Other changes possibly translated developmental physiological events, for example maturation of the adaptive immune system. The balance between S-type cystatins and cystatins A and B was modified, in favour of S-type cystatins at 6 months of age. Teeth eruption resulted in an increase in albumin abundance, whilst introduction of solid foods was associated with higher levels of β-2 microglobulin and S-type cystatins.

Conclusions

Salivary profiles were modified substantially between the ages of 3 and 6 months. Both teeth eruption and diet had an impact on abundance changes for some proteins, revealing dynamic interactions between saliva proteome, oral physiology and diet.     

Aggregatibacter actinomycetemcomitans leukotoxin is post-translationally modified by addition of either saturated or hydroxylated fatty acyl chains

Aggregatibacter actinomycetemcomitans, a common inhabitant of the human upper aerodigestive tract, produces a repeat in toxin (RTX), leukotoxin (LtxA). The LtxA is transcribed as a 114-kDa inactive protoxin with activation being achieved by attachment of short chain fatty acyl groups to internal lysine residues. Methyl esters of LtxA that were isolated from A. actinomycetemcomitans strains JP2 and HK1651 and subjected to gas chromatography/mass spectrometry contained palmitoyl (C16:0, 27-29%) and palmitolyl (C16:1 cis Δ9, 43-44%) fatty acyl groups with smaller quantities of myristic (C14:0, 14%) and stearic (C18:0, 12-14%) fatty acids. Liquid chromatography/mass spectrometry of tryptic peptides from acylated and unacylated recombinant LtxA confirmed that Lys(562) and Lys(687) are the sites of acyl group attachment. During analysis of recombinant LtxA peptides, we observed peptide spectra that were not observed as part of the RTX acylation schemes of either Escherichia coliα-hemolysin or Bordetella pertussis cyclolysin. Mass calculations of these spectra suggested that LtxA was also modified by the addition of monohydroxylated forms of C14 and C16 acyl groups. Multiple reaction monitoring mass spectrometry identified hydroxymyristic and hydroxypalmitic acids in wild-type LtxA methyl esters. Single or tandem replacement of Lys(562) and Lys(687) with Arg blocks acylation, resulting in a >75% decrease in cytotoxicity when compared with wild-type toxin, suggesting that these post-translational modifications are playing a critical role in LtxA-mediated target cell cytotoxicity.     

白蛋白微球颈外动脉灌注后经动—静脉短路溢出量及主要脏器分布的分析

目的　了解平均粒径 53 6μm的白蛋白微球 (AMS)经颈外动脉灌注后 ,经动 -静脉短路 (AVA)溢出部分微球的量和在重要脏器的分布。方法　经家兔颈外动脉灌注1 2 5I标记的微球后抽取颈外静脉血 ,测定放射剂量和静脉血中所含微球的比例 ;观察微球经家兔颈外静脉推注后全身各重要脏器组织中微球的分布情况。结果　经颈外动脉注入微球后仅有 0 51 %的放射剂量出现在静脉血中。微球经静脉推注后 ,主要聚集于肺 ,其它各重要脏器未见分布。结论　以平均粒径 53 6μm的白蛋白微球作为口腔颌面部肿瘤栓塞化疗药物的载体 ,全身副作用轻微 ,是安全可行的     

Compact poly-pyrrole layers formed at a liquid|liquid interface

Polymerization of surface active derivatives of pyrrole at the water|1,2-dichloroethane interface leads to the formation of a compact layer. New monomers have been synthesized with two pyrrole units in the molecule. Polymerization of these monomers proceeds at a lower potential and the density of the polymer layer is higher compared with monomers with one pyrrole unit in the molecule. Formation of the polymer layer has been monitored by cyclic voltammetry in the presence of transferable ions of different size and charge. Permeability of the polymer layer can be affected by the presence of a surface active derivative of cyclodextrin in the polymerization process.