The elution and breakdown behavior of constituents from various light-cured composites

Objectives

Constituents of dental composites can be released from dental fillings after polymerization. The aim of this study was to examine the time-related elution and breakdown of separable constituents of polymerized composites using deuterated solvents.

Method

Elution and breakdown of constituents were investigated with deuterated solvents methanol and water by gas chromatography/mass spectrometry of following composites for 180 days: Filtek™ Supreme XT, Filtek™ Supreme XT Flow, Tetric Ceram^®, Tetric Flow^®, Grandio^®, Grandio^® Flow.

Results

Within 180 days no compounds were formed as the products of breakdown. 19 compounds were identified as elution products: Bis-EMA, TEGDMA, DDDMA, EGDMA, MAA, BPA, CQ, HQME, DMABEE, CSA, BL, TEG, BHT, TINP, TPP, TPSB, DEDHTP, DCHP, ß-PHEA.The highest concentration of Bis-EMA was measured for Tetric Flow^® in deuterated methanol on day 90 at 36.993 mmol/l and in deuterated water also on day 90 at 0.031 mmol/l.The highest TEGDMA concentrations were measured for Grandio^® Flow in deuterated methanol on day 60 at 1.322 mmol/l and for Filtek™ Supreme XT Flow in deuterated water on day 3 at 0.689 mmol/l. The highest BPA concentration was measured for Tetric Flow^® in deuterated methanol on day 90 at 1.469 mmol/l. The highest BPA concentration was measured for Grandio^® in deuterated water on day 180 at 0.007 mmol/l.Significance Examination of time-related elution indicates that various elution products (e.g. Bis-EMA, BPA) were only released in small quantities during the first 90 days, but in high quantities between day 90 and day 180.     

国产与进口雷帕霉素洗脱支架的近期临床观察

目的对比研究国产雷帕霉素洗脱支架和进口雷帕霉素洗脱支架临床应用疗效。方法总结我科自2006年来行Cypher支架植入和Partner支架植入术的107例冠状动脉硬化性心脏病患者,其中Cypher支架组60例,Partner支架组47例。植入Cypher支架87枚,植入Partner支架56枚。结果两组一般情况对比,P值均>0.05,统计学无差异性。两组患者靶血管特征,P值>0.05,统计学无差异性。两组患者平均靶血管直径和平均靶病变长度对比Cypher支架组比支架组为Partner:(2.68±0.42)mm比(2.71±0.31)mm,(19.59±6.35)mm比(20.07±6.07)mm,P值均>0.05,统计学分析无显著差异性。临床随访6个月,两组患者均无急性和亚急性支架内血栓形成,无再发心肌梗死及死亡。再发心绞痛、再次血运重建和主要心血管事件对比,P值均>0.05,统计学无差异性。结论国产和进口雷帕霉素洗脱支架近期疗效相似。     

HPLC法测定奥卡西平及其制剂中有关物质

目的:建立使用C₁₈色谱柱同时测定奥卡西平及其制剂中8个杂质的高效液相色谱法。方法:采用ACE Excel C₁₈(4.6 mm×150 mm, 3μm)色谱柱,流速1.0 mL·min^-1,以6.8 g·L^-1磷酸二氢钾溶液(每1 000 mL加三乙胺2 mL,用磷酸调pH 6.0)为流动相A,乙腈-甲醇(11∶8)为流动相B,梯度洗脱,检测波长240 nm,柱温45℃。结果:奥卡西平与8个杂质分离度良好,奥卡西平和卡马西平分别在0.05～4.0μg·mL^-1和0.08～40μg·mL^-1浓度范围内呈现良好线性(r≥0.999 9),奥卡西平和卡马西平的定量限分别为1.03、0.65 ng,检测限分别为0.34、0.33 ng。共测定奥卡西平原料2个企业5批样品、奥卡西平片2个企业6批样品,其中1批原料检出杂质E,含量为0.004%;3批片剂检出卡马西平,含量分别为0.008%、0.005%、0.006%;1批片剂检出杂质C和杂质D,含量为0.006%、...     

HPLC-DAD法测定“武当三号金银花”不同部位中芦丁和木犀草苷的含量

目的：建立HPLC－DAD法测定“武当三号金银花”不同部位中芦丁和木犀草苷的含量。方法采用Fortis Xi Phenyl柱（250 mm ×4．6 mm,5μm）;流动相为乙腈（A）—0．5％冰醋酸溶液（B）进行线性梯度洗脱;检测波长为354 nm;柱温：30℃。结果芦丁和木犀草苷在各自测定的范围内均呈良好的线性关系（r≥0．9994）,平均回收率分别为99．4％、99．3％。结论该法操作简单,灵敏度高,重现性好,为控制“武当三号金银花”不同部位芦丁和木犀草苷的质量提供了一种可靠的方法。     

Electrophysiological Characteristics of Bipolar Membrane Carbon Leads With and Without Steroid Elution Compared With a Conventional Carbon and a Steroid-Fluting Platinum Lead

In a controlled study, the following four bipolar leads with passive fixation were implanted in 46 patients with the Siemens-MuItilog-VVI or Sensolog-VVIR-pacemakers: membrane covered activated porous carbon with steroid elution (Siemens 1402 T, 11 patients) and without (Siemens 1403 T, 15 patients); activated carbon (Siemens 1010T, 10 patients); and platinum with steroid elution (Medtronic CapSure 5026, 10 patients). Stimulation threshold (STH) (assessed by a vario-test), impedance (IMP), and the intracardial R wave potential (IRW) (both gauged by a telemetric method) were measured 1, 5, and 10 days as well as 3 and 6 months after implantation during unipolar and bipolar stimulation, chronaxie rheobase product (CBP) and energy consumption (EC) were systematically determined. Differing insignificantly at the first day after implantation, STH is significantly lower for the 1402 T and CapSure 5026 leads at the tenth day. However, the 1402 T lead shows a significant increase of STH in the follow-up, in contrast to the other leads. The lowest chronic STH was found in the CapSure 5026 lead (CRP is significantly lower in all other leads, too). IMP is significantly lower in the CapSure 5026 lead compared to 1010 T lead. EC does not differ significantly during chronic stimulation in spite of the best possible programming of pulse amplitude and duration. No significant changes of IRW were observed. Unipolar versus bipolar stimulation shows significantly lower STH, CRP, and IMP, differences of EC and IRW were insignificant. In conclusion, the addition of steroid in membrane covered carbon leads protracts the increase of STH, but does not prevent it. The CapSure 5026 lead shows advantageous stimulation characteristics, but energy consumption is not significantly reduced because of low impedance and impossibility of programming an appropriate low output in Multilog pacemakers.     

A novel method using formamide for the elution of antibodies from erythrocytes

BACKGROUND AND OBJECTIVES: Accurate identification of antibodies that sensitize red blood cells (RBCs) involves dissociating them from RBCs using an in vitro elution method that does not alter their antigen-binding properties, and analysis of the eluates against a panel of RBCs. MATERIALS AND METHODS: A method was developed that allowed efficient RBC antibody elution. Human polyclonal anti-D was used to sensitize Rh-positive RBCs, and known antigen-antibody disruptive reagents were tested using these RBCs. The best reagent conditions were optimized. Eluates made were tested and compared to results obtained with a glycine-acid-based commercial elution kit to determine efficacy. Patient samples that were positive with direct antiglobulin tests (DATs), and in vitro commercial antisera-sensitized RBCs representing clinically significant antibodies, were used for evaluating the new method. RESULTS: The formamide method was efficient at removing antibodies from RBCs. The patient samples with a positive DAT had antibodies recovered with the same specificity when compared to the acid-based technique. The length of preparation time was similar for both formamide and acid-based methods. Results of testing the eluates made from reagent RBCs sensitized with commercial antisera were distinct with antigen-positive and -negative erythrocytes. CONCLUSIONS: The formamide method compares well with acid techniques and may be an alternative choice of elution method.     

Transmural atrial pacing in patients with postoperative congenital heart disease

INTRODUCTION: Some patients with postoperative congenital heart disease require permanent cardiac pacing, but the use of transvenous or epicardial pacing leads may be limited by type of cardiac malformation, venous connections, body size, or fibrosis. Transmural atrial pacing may provide an alternative in difficult patients, but to date has been described in only a few articles with small patient numbers, and data from lead performance are lacking. METHODS AND RESULTS: Records were reviewed in 18 consecutive patients (4 months to 21 years old) with postoperative congenital heart disease receiving transmural atrial pacing leads from July 1994 to December 1996. Implantation materials and techniques were described. Lead sensing and capture thresholds obtained acutely and during short-term follow-up (mean: 11.0 months) were evaluated, and comparisons were made between patients with postoperative Fontan anatomy and non-Fontan patients, and between patients receiving steroid-eluting and nonsteroid leads. Overall, the median acute sensing and capture thresholds of transmural leads were 4.1 m V and 0.7 V at 0.5 msec, respectively. Median follow-up thresholds were 2.8 m V and 0.8 V, respectively. Performance of leads in Fontan patients was similar to those in non-Fontan patients. Steroid-eluting leads had a chronic capture threshold of 0.6 V versus 0.9 V for nonsteroid leads (P = 0.038). CONCLUSION: Transmural atrial pacing leads were successfully implanted in patients with diverse ages and types of postoperative congenital heart disease. Lead performance was acceptable both acutely and during the first year of follow-up.     

Xeroderma pigmentosum patients from the federal Republic of Germany: Decrease in post-UV colony-forming ability in 30 xeroderma pigmentosum fibroblast strains is quantitatively correlated with a decrease in DNA-incising capacity

Summary A total of 16 normal and 46 XP fibroblast strains from the Mannheim Collection were investigated for colony-forming ability following exposure to both UV light and the UV-like carcinogen (Ac)₂ONFln. The dose-response experiments included up to 13 dose levels. The exponential segments of the curves were analysed by linear regression and the negative reciprocal of the regression coefficient (D₀) was calculated for each cell strain.For quantitating the DNA-incising capacity, DNA elution curves were determined at several UV dose levels. Plotting the initial velocities of the elution curves versus the UV dose yielded a regression line, the slope of which was used to obtain the characteristic value E₀.Comparing D₀ with E₀ values showed that cell strains in which colony-forming ability was reduced suffered a reduction of DNA-incising capacity of the same magnitude. There were only 3 exceptional strains in which reduction of DNA-incising capacity was less pronounced than reduction of colony-forming ability. We have previouly shown (Fischer et al. 1982) that D₀ values from 27 XP strains of the Mannheim Collection were correlated with clinical symptoms. This correlation is now being extended by relating colony-forming ability to the magnitude of the DNA incision defect. From our data we conclude that the best quantitative biochemical denominator to explain the sun sensitivity of XP is that of a defective incision of UV-damaged DNA.A considerable similarity in sensitivity towards both UV light and (Ac)₂ONFln was found in 16 normal and 46 XP strains. This seems to indicate that UV-and (Ac)₂ONFln-induced DNA damage are removed to a large extent by the same pathways in human fibroblasts.Abbreviations XP xeroderma pigmentosum - (Ac)₂ONFln N-acetoxy-2-acetylaminofluorene - UV light ultraviolet light - HEPES N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid - ara-C 1--d-arabinofuranosyl cytosine This work was supported by the Deutsche Forschungsgemeinschaft, SFB 136