Aqueous extracts from dentin adhesives contain cytotoxic chemicals

It was the aim of our study to investigate the composition and cytotoxicity of aqueous elutes from five dentin adhesives currently used in clinical practice: Solobond Plustrade mark, Solisttrade mark, Scotchbond Multipurposetrade mark, Syntac SCtrade mark, and Prime & Bondtrade mark 2.1. Water extracts were analyzed by gas chromatography/mass spectrometry (GC/MS) and relative quantities of identified compounds were compared by means of an internal caffeine standard [%CF]. The in vitro cytotoxic effects of substances released into DMEM were determined using immortalized 3T3-fibroblast cultures. In addition, the cytotoxicity of ethylene glycol (EG), which was identified in the extracts of Syntac SC, was evaluated. All dentin adhesives tested released various chemical components, like comonomers (mainly ethylene glycol compounds), HEMA, and initiating substances (e.g., camphorquinone). Elutes of Solobond Plus, which contained very high amounts of TEGDMA, were extremely cytotoxic. Two bonding agents (Scotchbond Multi-purpose, Syntac SC), which released significant quantities of HEMA, induced severe cytotoxic effects. In contrast, extracts from Solist and Prime & Bond 2.1 had very small effects on cell proliferation; these elutes contained small amounts of released chemical compounds. EG, a product of HEMA hydrolysis, in concentrations ranging from 0.025-25 mM was not cytotoxic. In summary, these results provide evidence that all dentin adhesives tested in the present study release in aqueous media chemical compounds some of which (for example, TEGDMA and HEMA) are cytotoxic.     

Selective removal of composite sealants with near-ultraviolet laser pulses of nanosecond duration

It is often necessary to replace pit and fissure sealants and composite restorations. This task is complicated by the necessity for complete removal of the remaining composite to enable suitable adhesion of new composite. Previous studies have shown that 355-nm laser pulses from a frequency-tripled Nd:YAG laser can selectively remove residual composite after orthodontic bracket removal on enamel surfaces. Our objective is to determine if such laser pulses are suitable for selective removal of composite pit and fissure sealants and restorations. Optical coherence tomography is used to acquire optical cross sections of the occlusal topography nondestructively before sealant application, after sealant application, and after sealant removal. Thermocouples are used to monitor the temperature in the pulp chamber during composite removal under clinically relevant ablation rates, i.e., 30 Hz and 30 mJ/pulse. At an irradiation intensity of 1.3 J/cm2, pit and fissure sealants are completely removed without visible damage to the underlying enamel. At intensities above 1.5 J/cm2, incident laser pulses remove the resin layer while at the same time preferentially etching the surface of the enamel. Temperature excursions in the pulp chamber of extracted teeth are limited to less than 5 degrees C if air-cooling is used during the rapid removal (1 to 2 min) of sealants, water-cooling is not necessary. Selective removal of composite restorative materials is possible without damage to the underlying sound tooth structure.     

高强度玻璃离子材料结合非创伤性充填技术应用于乳牙封闭防龋

背景：以往报道的玻璃离子封闭剂耐磨性能差,抗折强度低,合面封闭剂很容易脱落。 目的：观察在非创伤性充填技术下高强度玻璃离子应用于幼儿乳牙窝沟封闭的效果。 方法：按自身对照的方法,对89名3岁幼儿的左或右半口符合窝沟封闭条件的乳磨牙在非创伤性充填技术下行玻璃离子窝沟封闭,对侧半口符合窝沟封闭条件的乳磨牙作空白对照。 结果与结论：非创伤性充填技术下窝沟封闭后6,18个月,玻璃离子完整保留率为94.15%及77.72%。6个月时牙位脱落率：下颌第二乳磨牙>下颌第一乳磨牙>上颌第二乳磨牙>上颌第一乳磨牙,18个月时牙位脱落率：下颌第二乳磨牙>上颌第二乳磨牙>下颌第一乳磨牙>上颌第一乳磨牙。非创伤性充填技术下玻璃离子封闭的乳牙患龋率远低于未作封闭的乳牙,6,18个月时差异均有显著性意义(P < 0.01)。提示非创伤性充填技术下高强度玻璃离子窝沟封闭在幼儿乳牙中的脱落率低,操作简单,防龋效果肯定。     

Analysis of PCB- and PCT-methylsulfones in the blood in yusho patients

Polychlorinated biphenyl (PCB)- and terphenyl (PCT)-methylsulfones were isolated from the blood of yusho patients sampled in 1987 and characterized by gas chromatography with mass spectrometry (GC/MS), electron capture detection (GC/ECD) and flame photometric detection (GC/FPD). GC/MS analysis for PCB-methylsulfones showed that all the blood tested (nine samples) contained the tri- and tetrachloro congeners. The concentrations of PCB-methylsulfones were estimated to be 15-120 ppb. PCT-methylsulfones detected in the same fraction, which were confirmed by GC/MS comparison with authentic samples as well as by GC/ECD and GC/FPD, consisted of tetra-, penta- and hexachloroterphenyl methylsulfone congeners. The levels of PCT-methylsulfones in six samples detected were preliminarily estimated to be 10-270 ppb, on the basis of a PCB-methylsulfone standard. Their origins and biological effects are unclear at present.     

Estrogenicity of bisphenol A and bisphenol A dimethacrylate in vitro.

Although pit and fissure sealants have been utilized extensively in dentistry as a way of preventing occlusal caries, results described by Olea et al. (1996) raised concerns about the safety of sealants and other resin-based dental materials due to the reported presence of bisphenol A (BPA) and its dimethacrylate ester (BPA-DM). Although the release of these compounds from dental materials has not been substantiated by two subsequent studies, we believed it was important to confirm or refute the report that BPA and BPA-DM have estrogenic activity in vitro. We grew breast cancer cells (MCF-7, T-47D, ZR-75-1) known to proliferate under estrogenic stimulation in phenol red-free DMEM containing human serum and concentrations of BPA or BPA-DM ranging from 10(-8)M to 5 x 10(-6)M. After 1 week, plates were harvested for crystal violet or sulforhodamine-B assays, and the optical densities of groups of treated cells were compared with values from control cells. At concentrations at or above 10(-6)M, both BPA and BPA-DM significantly increased cell proliferation (p < 0.05), comparable to the increase seen with 10(-9)M of estrogen. Flow cytometric methods demonstrated that these mitogenic effects occurred within 24 h of exposure to estrogen, BPA, or BPA-DM. The increase in DNA synthesis was analogous to that seen with estrogen stimulation. Thus, we confirmed that BPA and BPA-DM cause cell proliferation at micromolar concentrations that exceed the effective concentrations of estrogen by 1 to 10,000-fold.     

The A, M, N, and P1 Blood Group Substances in Butanol Extracts of Human Erythrocytes

Aqueous phase and butanol phase extracts of group A₁, O, M. N, P₁ and P₂ human erythrocytes prepared by extraction of red cell stromata with n-butanol were examined for the presence of blood group substances in inhibition of agglutination experiments using antisera and test cells of human origin. Group A substance was recovered in both aqueous phase and butanol phase extracts, M and N substances in aqueous phase extracts only, and P₁ substance only in butanol phase extracts. Use of high concentrations of extract resulted in detection of P₁ activity in aqueous phase extracts and of N specific inhibition in the aqueous phase extracts of group M erythrocytes. Distilled water appeared to be superior to digitonin and hypotonic phosphate buffer solutions for preparation of stromata for the reccvery of group A and M substances in the butanol extracts but not for group N and P₁ substances.     

Modulatory activities of Agelanthus dodoneifolius (Loranthaceae) extracts on stimulated equine neutrophils and myeloperoxidase activity

Agelanthus dodoneifolius DC Danser (Loranthaceae) is used for the treatment of various diseases including asthma. The aqueous and hydroalcoholic extracts have been reported to have anti-inflammatory, spasmolytic and bronchorelaxant activities. The present study investigates the effects of the aqueous decoction and the diethyl ether, ethyl acetate and butanolic fractions of Agelanthus dodoneifolius DC Danser (Loranthaceae) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by phorbol 12-myristate 13-acetate (PMA)-stimulated equine neutrophils and on purified equine MPO activity. ROS production and MPO release by the PMA-stimulated neutrophils were measured by the lucigenin-enhanced chemiluminescence and ELISA assays, respectively. Specific immunological extraction followed by enzymatic detection (SIEFED) was used to specifically measure the equine MPO activity. Identification and quantification of the individual and total phenolic and flavonoid compounds were performed using UPLC-MS/MS equipment and colorimetric methods involving Folin-Ciocalteu and AlCl?, respectively. All the tested extracts displayed dose-dependent inhibitory effects on the oxidant activities of neutrophils; a stronger effect was observed with the organic fractions than the aqueous decoction. These findings could be correlated with a high content of phenolic and flavonoid compounds. The results confirm the previously shown anti-inflammatory effect of Agelanthus dodoneifolius and its potential use for the treatment of neutrophil-dependent inflammatory diseases.     

The H, HI, I and i blood group antigens in butanol extracts of rabbit tissues

Aqueous and butanol phase extracts of rabbit erythrocytes and the tissues gastric mucosa, liver, lung and kidney were examined by inhibition of agglutination for the presence of H, HI, I and i blood group substances. Of the four specificities, only I substance was recovered from erythrocytes and only in the aqueous phase extracts. Both aqueous and butanol extracts of gastric mucosae contained H substance, but HI and I were present only in the aqueous extracts of this tissue. Extracts of rabbit lungs only had H and I activity and only in the aqueous phase. No H, HI, I or i substance was detected in any of the extracts of liver and kidney. Reduced levels of H substance were found in aqueous extracts of gastric mucosae of 'A-like' rabbits. Three H specificities were demonstrated in the butanol phase extracts of gastric mucosae of rabbits. These specificities were similar to those previously shown in extracts of gastric mucosae and erythrocytes of humans.     

人工乳房硅凝胶填充物中小分子物质的检测

目的初步建立了检测人工乳房硅凝胶填充物中小分子物质的方法,并对市场上的人工乳房产品进行检测。方法采用气相色谱-质谱联用仪对人工乳房硅凝胶填充物中小分子物质进行了分析,优化了溶剂切除时间、质荷比、扫描范围等实验条件。结果用该法测定出了人工乳房硅凝胶填充物中的数种小分子物质,包括烷烃类和硅氧烷类。结论国内产品与国外产品的差距通过改进生产工艺和控制工艺过程,是可以逐渐缩小的。人工乳房硅凝胶填充物中小分子物质气相色谱-质谱联用检测方法,灵敏度高,重复性好,简便可行,可用于人工乳房产品的质量控制,为国家对此类产品的监管提供了技术支撑。     

The I,i, and HI Blood Group Antigens in Extracts of Human Erythrocytes

Extracts of stromata of human adult and newborn (cord) erythrocytes were prepared with n-butanol. The aqueous phase and butanol phase extracts were examined for the presence of blood group I, i, HI and H substances in inhibition of agglutination experiments. The recovery of HI activity in both the aqueous and butanol phase extracts of adult red cells but only in the aqueous phase of cord cells is reported here for the first time. The i specificity was present in the aqueous phase but not in the butanol phase of cord erythrocytes, also not previously reported. Although the recovery of I but not i substance in aqueous phase extracts of adult cells had been shown by other workers, examination of the butanol phase extracts for I and i substances had not been documented. In the present study, Ii substances were not demonstrable in any of the butanol phase extracts of adult and cord erythrocytes.     

The I, i, and HI Blood Group Antigens in Extracts of Human Erythrocytes

Extracts of stromata of human adult and newborn (cord) erythrocytes were prepared with n-butanol. The aqueous phase and butanol phase extracts were examined for the presence of blood group I, i, HI and H substances in inhibition of agglutination experiments. The recovery of HI activity in both the aqueous and butanol phase extracts of adult red cells but only in the aqueous phase of cord cells is reported here for the first time. The i specificity was present in the aqueous phase but not in the butanol phase of cord erythrocytes, also not previously reported. Although the recovery of I but not i substance in aqueous phase extracts of adult cells had been shown by other workers, examination of the butanol phase extracts for I and i substances had not been documented. In the present study, Ii substances were not demonstrable in any of the butanol phase extracts of adult and cord erythrocytes.     

The I, i, and HI blood group antigens in extracts of human erythrocytes

Extracts of stromata of human adult and newborn (cord) erythrocytes were prepared with n-butanol. The aqueous phase and butanol phase extracts were examined for the presence of blood group I, i, HI and H substances in inhibition of agglutination experiments. The recovery of HI activity in both the aqueous and butanol phase extracts of adult red cells but only in the aqueous phase of cord cells is reported heare for the first time. The i specificity was present in the aqueous phase but not in the butanol phase of cord erythrocytes, also not previously reported. Although the recovery of I but not i substance in aqueous phase extracts of adult cells had been shown by other workers, examination of the butanol phase extracts for I and i substances had not been documented. In the present study, Ii substances were not demonstrable in any of the butanol phase extracts of adult and cord erythrocytes.     

流动纳米树脂预防性窝沟龋充填

背景：预防性树脂充填术由于不采用传统的预防性扩展,只去除少量的龋坏组织后即用复合树脂或玻璃离子材料充填龋洞,而未患龋的窝沟使用封闭剂保护。 目的：通过应用美国3M公司生产的Filtek Z350流动纳米树脂对窝沟可疑龋、初龋磨除后进行预防性充填,观察并评价其临床效果,探索预防性充填治疗早期窝沟龋的新方法。 方法：对196例6~25岁患者磨牙的牙合 面窝沟龋在去除龋坏的牙体组织后,采用Eadper prompt自酸蚀粘结技术,用Filtek Z350流动纳米树脂对整个牙面进行预防性充填术,并采用对侧同名牙或邻牙也有窝沟龋者用同一公司生产的ClinproTM可见光固化变色窝沟封闭剂充填作对照研究。 结果与结论：随治4年后发现该方法涂膜保留率高,能有效阻止龋病的进一步发展。实验组与对照组在术后1,2年时的涂膜保留率差异无显著性意义,而在第3,4年时差异有显著性意义(P < 0.01、P < 0.05)。龋病发生率在1,2年时差异无显著性意义,而在3,4年时差异有显著性意义(P < 0.05)。提示Filtek Z350流动纳米树脂预防性窝沟充填是一种有效阻止窝沟早期龋进一步发展的方法。     

The A, M, N, and P1 blood group substances in butanol extracts of human erythrocytes

Aqueous phase and butanol phase extracts of group A1, O, M, N, P1 and P2 human erythrocytes perpared by extraction of red cell stromata with n-butanol were examined for the presence of blood group substances in inhibition of agglutination experiments using antisera and test cells of human origin. Group A substance was recovered in both aqueous phase and butanol phase extracts, M and N substance in aqueous phase extracts only, and P1 substance only in butanol phase extracts. Use of high concentrations of extract resulted in detection of P1 activity in aqueous phase extracts and of N specific inhibition in the aqueous phase extracts of group M erythrocytes. Distilled water appeared to be superior to digitonin and hypotonic phosphate buffer solutions for preparation of stromata for the recovery of group A and M substances in the butanol extracts but not for group N and P1 substances.     

Synthetic pyrethroid insecticides in fish: Analysis by gas chromatography‐mass spectrometry operated in the negative ion chemical ionization mode and ELISA

Brown trout (Salmo trutta) were captured from a headwater stream contaminated with moth‐proofing agents. Synthetic pyrethroid residues within the tissues were obtained by ultrasonic extraction and examined by gas chromatography‐mass spectrometry operated in the negative ion chemical ionization mode (GC/NCI‐MS). Both permethrin and cyfluthrin had been bioaccumulated by the fish and the mean concentrations ( ± standard deviation) recorded were 2046 ( ± 203) μg kg^‐1 and 25.4 ( ± 46.9) μg kg^‐1 respectively. The concentrations of these pyrethroids are the highest recorded for freshwater fish captured from a natural ecosystem. At the time of sampling, permethrin could be detected within the stream water (0.034 μg l^‐1) while cyfluthrin could not. A mean relative bioconcentration factor of approximately 60 000 was derived for the brown trout which was also greater than any previously determined for freshwater fish. The fish tissue extracts were also analyzed through use of an ELISA for permethrin. The ELISA reported consistently lower concentrations than those obtained by GC/NCI‐MS. This was attributed to analyte losses during preparation of the sample extracts in a form suitable for incorporation into the ELISA. The concentrations obtained by ELISA were significantly correlated with those obtained by GC/NCI‐MS (R² = 0.985, n = 5). Overall, the ELISA appeared to be suitable for the detection of permethrin in fish when present at concentrations in excess of the maximum residue level suggested for many foods by the Commission of the European Economic Community.     

Identification of 2,4-dichlorophenol in females of the American dog tick,Dermacentor variabilis (Acari: Ixodidae), and its possible role as a component of the attractant sex pheromone

Presence of 2,4-dichlorophenol (2,4-DCP) in extracts of fed and nonfed adult female Dermacentor variabilis (Say) by gas chromatography and mass spectroscopy (GC/MS) is reported. 2,4-DCP was detected as part of a mixture with 2,6-dichlorophenol, which is the attractant sex pheromone in this species in a 1:9 ratio, respectively. Extracts did not contain the monochlorinated phenols, 2-chlorophenol and 4-chlorophenol. None of these chlorophenols were detected in eggs. 2,4-DCP is comparable in efficacy to 2,6-DCP as an attractant sex pheromone, prompting attraction, arrestment and feeding posture behavior by fed males. It is also present in the female adult.     

The A,M, N,and P1 Blood Group Substances in Butanol Extracts of Human Erythrocytes

Aqueous phase and butanol phase extracts of group A₁, O, M. N, P₁ and P₂ human erythrocytes prepared by extraction of red cell stromata with n-butanol were examined for the presence of blood group substances in inhibition of agglutination experiments using antisera and test cells of human origin. Group A substance was recovered in both aqueous phase and butanol phase extracts, M and N substances in aqueous phase extracts only, and P₁ substance only in butanol phase extracts. Use of high concentrations of extract resulted in detection of P₁ activity in aqueous phase extracts and of N specific inhibition in the aqueous phase extracts of group M erythrocytes. Distilled water appeared to be superior to digitonin and hypotonic phosphate buffer solutions for preparation of stromata for the reccvery of group A and M substances in the butanol extracts but not for group N and P₁ substances.     

Enhanced excretion of intermediates of aromatic amino acid catabolism during chlorophenol degradation due to nutrient limitation in the yeast Candida maltosa

Incubation of phenol-induced cells of the yeast Candida maltosa SBUG 700 with mono- and dichlorophenols resulted in the formation of metabolites of the substrates and of further metabolites not related to the degradation pathway of the substrates. These additional compounds, identified as 4-hydroxyphenylacetic acid (4-HPA), phenylacetic acid (PA), indolylacetic acid (IA) and indolylethanol (IE) by means of HPLC and GC/MS, were not excreted in incubation experiments with glucose. The excretion of these metabolites of aromatic amino acid metabolism is not caused by toxic effects of the phenol derivatives, but seems to be a result of carbon and nitrogen starvation of yeast cells.     

FiltekTM Z 350纳米流动树脂微创修复细小窝沟龋

背景：传统的细小窝沟龋修复需要按Ⅰ类洞形进行预备,对牙体组织破坏较多。 目的：评价流动纳米树脂微创修复细小窝沟龋的临床效果。 方法：选择14~30岁磨牙有窝沟龋且对侧同名牙或邻牙也有窝沟龋患者167例,在一侧磨牙牙合面窝沟龋去除龋坏牙体组织后,采用Adper Single Bond 2全酸蚀黏结技术,用Filtek ^TM Z350流动纳米树脂充填整个微创窝洞作为实验组,对侧同名牙或邻牙窝沟龋用同一公司生产的Filtek ^TM Z350纳米树脂充填作对照。 结果与结论：随访2年后发现实验组Z350流动纳米树脂填充体保留率高,边缘完整性好,边缘着色率低,树脂保留率、边缘完整性及边缘着色率高于对照组(P < 0.05)。提示Filtek ^TM Z350流动纳米树脂微创窝沟充填可有效修复细小窝沟龋。