Resin glycosides from the leaves and stems of <Emphasis Type="Italic">Ipomoea digitata</Emphasis>

Alkaline hydrolysis of the ether-soluble resin glycoside (jalapin) fraction of the leaves and stems of Ipomoea digitata L. (Convolvulaceae) gave six organic acids, isobutyric, (S)-2-methylbutyric, tiglic, n-decanoic, n-dodecanoic, and cinnamic acids, and two glycosidic acids, quamoclinic acid A and operculinic acid A. Further, a new genuine resin glycoside, named digitatajalapin I, was isolated from the jalapin fraction, along with three known resin glycosides. Their structures have been determined on the basis of chemical and spectroscopic data.     

丹参中丹参酮ⅡA的提取分离研究

目的 研究丹参中丹参酮ⅡA的提取纯化工艺.方法 以HPLC法为检测手段,对丹参酮ⅡA的提取工艺,D101型大孔树脂分离纯化丹参酮ⅡA的树脂柱径高比、药液质量浓度、上柱吸附体积流量、洗脱体积流量、生药吸附量、解吸溶媒及其最佳用量等因素进行考察.结果 丹参中丹参酮ⅡA的最佳提取分离工艺为:避光条件下,丹参药材用6倍量(g·...     

大孔吸附树脂对红花多糖脱色工艺的影响研究

目的:探讨大孔吸附树脂对红花多糖脱色工艺的影响。方法:采用单因素试验,以脱色率和多糖保留率作为评价指标,比较AB-8、HPD-400A、HPD-100、HPD-750、D101、ADS-17等6种不同型号大孔吸附树脂在温度、多糖浓度、pH值、吸附流速、洗脱剂5个方面对红花多糖脱色效果的影响。结果:HPD-100大孔吸附树脂对红花多糖的脱色率和保留率较为理想。最佳工艺为40℃,多糖浓度为5 mg·mL-1,pH值为4,流速为1 ml·min-1,洗脱剂为pH 4的蒸馏水。在该条件下色素的吸附率可达86.71%,多糖保留率为72.10%。结论:HPD-100大孔树脂对红花多糖可以获得较高的脱色率和保留率。     

Effect of chlorhexidine incorporation into a self-etching primer on dentine bond strength of a luting cement

Objectives

This study investigated the effect of incorporating chlorhexidine in a self-etching primer on the bond strength of an adhesive resin cement to dentine and on antibacterial activity.

Methods

Experimental self-etching primers were prepared by adding chlorhexidine (CHX) diacetate to ED primer 2.0 (Kuraray Medical Inc.) to obtain chlorhexidine concentrations of 1.0 wt% and 2.0 wt%. Human occlusal dentine surfaces were conditioned for 30 s using the experimental primers or pure ED primer. Composite blocks were luted using Panavia F 2.0 (Kuraray Medical Inc.). After storage in water for 24 h, the bonded teeth were sectioned into 0.9 mm × 0.9 mm beams and stressed to failure in tension to examine microtensile bond strength (μTBS). Fractured surfaces were examined with a field-emission scanning electron microscopy (FE-SEM). The morphology of dentine surfaces that were conditioned with each primer was also observed under FE-SEM. An agar diffusion test was performed to examine the antibacterial effect of each primer against Streptococcus mutans and Enterococcus faecalis.

Results

Addition of chlorhexidine to the primer had significant effects (p < 0.001) on μTBS and antibacterial effect. No significant difference in μTBS was found between the groups that contained 0% and 1% chlorhexidine in the primer (p = 0.095). Conversely, the group that contained 2% chlorhexidine showed significantly lower μTBS and pronounced cohesive failures within the thin layer of the primer.

Conclusions

Incorporation of chlorhexidine into ED primer 2.0 showed significant antibacterial activities. Conditioning with the 1% chlorhexidine-containing primer had no adverse effect on μTBS.     

A critical analysis of the degree of conversion of resin-based luting cements

Objective

This study analyzed the degree of conversion (DC%) of four resin-based cements (All Ceram, Enforce, Rely X ARC and Variolink II) activated by two modes (chemical and dual), and evaluated the decrease of DC% in the dual mode promoted by the interposition of a 2.0-mm-thick IPS Empress 2 disc.

Material and Methods

In the chemical activation, the resin-based cements were prepared by mixing equal amounts of base and catalyst pastes. In the dual activation, after mixing, the cements were light-activated at 650 mW/cm² for 40 s. In a third group, the cements were lightactivated through a 2.0-mm-thick IPS Empress 2 disc. The DC% was evaluated in a FT-IR spectrometer equipped with an attenuated total reflectance crystal (ATR). The data were analyzed by two-way ANOVA and Tukey''s HSD test.

Results

For all resin-based cements, the DC% was significantly higher with dual activation, followed by dual activation through IPS Empress 2, and chemical activation (p<0.05). Irrespective of the activation mode, Rely X presented the highest DC% (p<0.05). Chemically activated Variolink and All Ceram showed the worst results (p<0.05). The DC% decreased significantly when activation was performed through a 2.0-mm-thick IPS Empress 2 disc (p<0.05).

Conclusions

The results of the present study suggest that resin-based cements could present low DC% when the materials are dually activated through 2.0 mm of reinforced ceramic materials with translucency equal to or less than that of IPS-Empress 2.     

An effect of immediate dentin sealing on the shear bond strength of resin cement to porcelain restoration

PURPOSE

The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS).

MATERIALS AND METHODS

Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent (Excite® DSC) and cemented with Variolink® II resin cement. IDS/SE (immediate dentin sealing, Clearfil™ SE Bond) and IDS/SB (immediate dentin sealing, AdapterTM Single Bond 2) were light-cured after application of dentin bonding agent (Clearfil™ SE Bond and Adapter™ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with Variolink® II resin cement. Dentin bonding agent (Excite® DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope.

RESULTS

The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial.

CONCLUSION

When preparing teeth for indirect ceramic restoration, IDS with Clearfil™ SE Bond results in improved shear bond strength compared with DDS.     

不同血液净化方法对慢性肾衰竭维持性血液透析患者血清β2-微球蛋白的影响

目的 探讨不同血液净化方法对慢性肾衰竭维持性血液透析(MHD)患者血清β2-微球蛋白(β2-MG)的清除效果.方法 将40例慢性肾衰竭MHD患者随机分为四组:血液透析(HD)组,高通量血液透析(HFD)组,血液透析滤过(HDF)组,HD+血液吸附(AP)组,每组各10例.记录患者治疗前后血清β2-MG测得值并进行组内和组间统计学比较.结果 HD组第1次血液净化后β2-MG测得值[(53.49±1.15)mg/L]较第1次血液净化前(基线值)[(49.10±2.31)ms/L]上升但差异无统计学意义(P>0.05),6个月血液净化后β2-MG测得值[(55.63±1.30)mg/L]较基线值上升且差异有统计学意义(P<0.05).HFD组、HDF组和HD+AP组第1次血液净化后及6个月血液净化后β2-MG测得值较基线值均有明显下降趋势(P<0.05).并且HD+AP组6个月血液净化后β2-MG测得值较HFD组和HDF组下降趋势更为明显(P<0.05).结论 HD对β2-MG无清除效果,HFD、HDF和HD+AP能有效清除β2-MG,并且6个月后HD+AP清除β2-MG效果更佳.     

Cytotoxicity of 3D printed resin materials for temporary restorations on human periodontal ligament (PDL-hTERT) cells

ObjectivesVarious dental resin materials are available for the fabrication of temporary restorations using modern additive printing methods. Albeit these materials are placed for several months in intimate contact with dental hard and soft tissues, including the gingival crevice, there exists only insufficient evidence on the biocompatibility of these materials. This in vitro study aimed to delineate the biocompatibility of 3D printable materials on periodontal ligament cells (PDL-hTERTs).MethodsSamples of four dental resin materials for additive fabrication of temporary restorations using 3D printing (MFH, Nextdent; GC Temp, GC; Freeprint temp, Detax; 3Delta temp, Deltamed), one material for subtractive fabrication (Grandio disc, Voco) and one conventional temporary material (Luxatemp, DMG) were prepared with a standardized size according to the manufacturer’s instructions. Human PDL-hTERTs were exposed to resin specimens or eluates of the material for 1, 2, 3, 6 and 9 days. For determination of cell viability, XTT assays were performed. In addition, the expression of the proinflammatory cytokines interleukin 6 and 8 (IL-6 and 8) was assessed in the supernatants with ELISA. Cell viability and the expression of IL-6 and 8 in presence of the resin material or their eluates was compared with untreated controls. Immunofluorescence staining for IL-6 and IL-8, as well as scanning electron microscopy of the discs after culturing, were performed. Differences between groups were analyzed with Student´s t-test for unpaired samples.ResultsCompared to untreated control samples, the exposure against the resin specimen induced strong reduction of cell viability in case of the conventional material Luxatemp (p < 0.001) and the additive material 3Delta temp (p < 0.001) irrespective of the observation period. On the contrary, the presence of eluates of the various materials induced only minor changes in cell viability. Considering IL-6 (day 2: p = 0.001; day 6 and 9: p < 0.001) and IL-8 (day 1: p = 0.001; day 2, 3, 6, 9: p < 0.001) their expression was strongly reduced in presence of the eluate of Luxatemp. Except for IL-6 at day 1 and 6 also the material 3Delta temp caused significant reduction of both proinflammatory mediators at any time point.SignificanceThe conventional material Luxatemp and the additive material 3Delta temp appear to severely affect cell viability when in direct contact with PDL-hTERTs. The other tested materials of this new category of additive materials and the subtractive material Grandio seem to induce only minor changes in direct contact with these cells. Therefore, they could serve as a viable alternative in the fabrication of temporary restorations.     

树脂切片和石蜡切片在精子细胞核的大小估计中的对比

从石蜡切片上估计的早期(球形)精子细胞核的体积加权平均体积和平均断面直径,均显著小于树脂切片上的估计,结果分别为61±4(平均值±标准差)μm~3和4.4±0.1μm 以及102±18μm~3和5.0±0.2μm。