Oxime@Zirconium-Metal-Organic Framework Hybrid Material as a Potential Antidote for Organophosphate Poisoning.

A novel material with dual activity toward organophosphate (OP) poisoning, based on Zr-MOF-808 and neutral oxime RS69N, has been prepared. The hybrid material has a significant drug payload (5.2 ± 0.9 oxime to MOF-808 molar ratio) and shows a sustained oxime release in simulated physiological media, leading to the successful reactivation of OP-inhibited acetylcholinesterase. At the same time, the hybrid system presents an efficient and moderately fast removal rate of a toxic organophosphorus model compound (diisopropylfluorophosphate) from simulated physiological media (t1/2 = 183 min; 95% removal rate after 24 h).

Effect of 30 % hydrogen peroxide on mineral chemical composition and surface morphology of bovine enamel.

A combination of atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), and gas adsorption techniques was used to characterize the effect of 30 % hydrogen peroxide (HP) on enamel surface. To perform the analyses of AAS, 1 ml of 30 % HP was added to 30 mg of a bovine enamel powder sample (150-200 µm fractions) for times of 5, 20, 60, 90, and 120 min; then 5 ml of the solution was withdrawn after each time period to measure [Ca(2+)] ions. The remaining powder was recovered and analyzed by FTIR. For SEM and gas adsorption tests, 4 × 4 mm(2) enamel sectioned samples were polished and 30 % HP was applied on the surface for the same time periods. AAS data show that 30 % HP treatment mobilized calcium from the enamel at all times studied. FTIR spectra showed that the total amount of phosphate and carbonate mineral contents such as amide I decreased significantly. SEM revealed that randomly distributed areas throughout the smooth enamel surface treatment became rougher and more irregular. These alterations indicate that surface damage increases with increasing durations of HP treatment. Gas adsorption analysis proved that bleached enamel is a typically non-porous material with a small specific surface area which decreases slightly with the 30 % HP treatment. In sum, 30 % HP induced a significant alteration of the organic and mineral part of the enamel, leading to the release of calcium and a rougher, more irregular enamel surface on randomly distributed areas.

Influence of microstructure on optical properties of CAD-CAM lithium disilicate glass-ceramics.

OBJECTIVES: To evaluate the influence of microstructure and chemical composition on the optical properties of CAD-CAM lithium disilicate glass-ceramics. METHODS: Samples (n = 5; 1.0 mm thickness) of shades A1, A2, and A3 were fabricated from CAD-CAM ceramic blocks (Ivoclar Vivadent): IPS e.max® CAD LT (emLT) and HT (emHT). Samples were polished to 1.0 ± 0.01 mm in thickness. The optical properties (R- reflectance; T- transmittance; µs'- reduced scattering and µa- absorption coefficients) from the post-crystallized samples were determined using the inverse adding-doubling (IAD) method based on integrating-sphere measurements. Additionally, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to evaluate the microstructural properties. Energy-dispersive X-ray (EDX) was employed to analyze the chemical composition. The chemical and structural characterization were performed before and after crystallization of the ceramic samples. RESULTS: emLT showed higher values of µs'and lower values of µa and T than emHT for each shade in all wavelengths (p < 0.003). Considering T for emHT, there were no statistical differences for shades A1 and A2 at 488 nm and 514.5 nm (p > 0.003) and shades A1 and A3 at 457.9 nm (p > 0.003). emLT showed particle length ranging from 0.74 to 2.78 µm (mean = 1.57 µm and RF-relative frequency = 28 %) and particle width ranging from 0.21 to 0.74 µm (mean = 0.30 µm and RF = 31 %). emHT showed particle length ranging from 0.83 to 3.08 µm (mean = 1.86 µm and RF = 21 %) and particle width ranging from 0.24 to 1.12 µm (mean = 0.56 µm and RF = 28 %). In comparison with emHT, emLT showed greater vol% for C, K, and Zr and lower vol% for O and Al. SIGNIFICANCE: The optical properties of CAD-CAM lithium disilicate glass-ceramics are influenced by the chemical composition and, consequently, by the material microstructure.

Percentage exposure of root dentin collagen after application of two irrigation protocols with manual or rotary instrumentation and two methacrylate resin-based sealers.

PURPOSE: To compare the percentage of collagen exposed in dentin root thirds after two irrigation protocols with manual or rotary instrumentation using two methacrylate resin-based sealers. MATERIALS AND METHODS: Forty-eight single-root human teeth were prepared with manual (n = 24) or nickeltitanium ProFile rotary (n = 24) instrumentation, using 5% NaOCl between instruments and 5 ml 17% EDTA as final irrigant or 20% citric acid + 2% chlorhexidine (CHX) between instruments and as the final irrigant. RealSeal or EndoREZ were used as filling materials. One 1-mm slice per third was abraded and stained with Masson's trichrome method. Mean exposed collagen values were obtained in four areas from each section (at 60X magnification) and a complete factorial ANOVA was used to analyze the influence of the study variables. Non-parametric Mann-Whitney's test was used to compare groups. Differences with p < 0.05 were considered significant. RESULTS: A significantly higher percentage of collagen was exposed in all thirds with the use of the 20% citric acid + 2% CHX protocol with rotary vs manual instrumentation, but percent collagen exposed did not differ as a function of the filling material. After the 5% NaOCl + 17% EDTA protocol, the percentage of collagen exposed did not differ between rotary and manual instrumentation but was higher with the use of RealSeal. CONCLUSION: The highest percentage exposure of collagen was with 20% citric acid + 2% CHX using rotary instrumentation, regardless of the filling material.

Selective removal of mineral and organic components of bovine enamel by phosphoric acid.

PURPOSE: To follow the chemical composition of bovine enamel during phosphoric acid-induced demineralization. MATERIALS AND METHODS: Enamel samples were ground into a fine powder, selecting the 150- and 200-µm fractions in order to obtain a more homogeneous study material. They were immersed in diluted phosphoric acid (0.1%) for increasing durations ranging from 1 to 1440 min. The chemical composition of the solution and enamel powder was determined after each sequential treatment by means of atomic absorption (AA) and Fourier transform infrared (FTIR) spectroscopy. RESULTS: AA data revealed that the amount of calcium mobilized to the solution by the acid treatment was higher at shorter exposure times. However, FTIR data showed that the degree of mineralization of the enamel remained constant during the treatment, indicating that the mineral and organic components were lost at the same rate. Interestingly, poorly crystalline phosphate and carbonate-rich mineral components were preferentially removed and were presumably the main source of calcium released by the acid exposure. FTIR results also demonstrated that organic components rich in hydrophobic groups were preferentially removed during acid treatment. CONCLUSION: Etching with phosphoric acid produces a nonhomogeneous demineralization of bovine enamel, with the selective removal of poorly crystalline mineral and hydrophobic organic components.

Demineralization effects of phosphoric acid on surface and subsurface bovine enamel bleached with in-office hydrogen peroxide.

PURPOSE: To measure the demineralization capacity of 37% phosphoric acid on surface and subsurface bovine enamel after bleaching with hydrogen peroxide (H2O2). MATERIALS AND METHODS: Three equally-sized sections with 16 mm2 of exposed enamel surface were obtained from the enamel of 10 bovine incisors. One specimen sample from each crown was assigned to one of three groups (n = 10): group I, no bleaching agent; group II, bleached with 38% H202 for 20 min; or group III, 30% H202 for 60 min. After 24 h, the thickness of specimens was measured and they were immersed in 37% phosphoric acid solution, of which 5-ml aliquots were collected at 30 s and 60 s. Specimens were then ground to a depth of 25 µm and again immersed in 37% phosphoric acid solution. This procedure was repeated for enamel depths of 50 and 100 µm. Ca2+ concentrations in the phosphoric acid aliquots were measured by atomic absorption spectroscopy. RESULTS: No significant differences were found in the total amounts of extracted Ca2+ between bleached and unbleached specimens (F = 0.142; p = 0.869). The amount of Ca2+ extracted was similar among the four depth levels in the unbleached and in the 30% H202 bleached specimens. A significantly larger amount of Ca2+ was obtained at 25 µm depth (subsurface) from specimens treated with 38% H202. CONCLUSIONS: Pre-bleaching with 38% H202 significantly increased the decalcifying effect of phosphoric acid on subsurface enamel at a depth of 25 µm compared to 100 µm, whereas pre-bleaching with 30% H202 did not modify this effect at any level.

Skin and Arterial Wall Deposits of 18F-NaF and Severity of Disease in Patients with Pseudoxanthoma Elasticum.

Pseudoxanthoma elasticum (PXE) is a genetic disease characterized by the calcification of elastin fibers. Our aim was to quantify vascular calcification in the arteries and the deposition of 18F-sodium-fluoride (18F-NaF) in the skin and vessel walls with positron emission tomography/computed tomography. This was an observational study including 18 patients with PXE. Vascular calcification was measured in Agatston units, and deposition in the skin and vessel walls was shown using target-to-background ratio (TBR). Severity of the disease was scored by Phenodex. We found higher vascular calcification in the popliteal, femoral, and aortic arch vessels compared to other vascular regions; however, the uptake of radiotracer was the highest in the aorta and femoral arteries. In the skin, the highest uptake was observed in the neck and the axillae. There was no significant association between 18F-NaF deposition in the arteries or skin and the global Phenodex score. In contrast, the Phenodex score was significantly associated in univariate analyses with the averaged vascular calcium score (p < 0.01). In the neck, patients with higher skin Phenodex scores exhibited higher radiotracer uptake. As a conclusion, because vascular calcification is physiological, our data suggested that the detection of cutaneous (neck) 18F-NaF deposits might serve to monitor the calcification process in the short-term for patients with PXE.

Demineralization effects of hydrogen peroxide on bovine enamel and relation to shear bond strength of brackets.

PURPOSE: To measure the demineralization capacity of 37% phosphoric acid and shear bond strength (SBS) of brackets attached on bovine enamel at different times after bleaching with 30% hydrogen peroxide. MATERIALS AND METHODS: Four equally-sized pieces of each crown from 18 bovine incisors were randomly distributed among 7 groups (n = 10). After bleaching with 30% hydrogen peroxide for 1 h, specimens were stored in artificial saliva for 0 h, 24 h, or 1, 2, 3, or 4 weeks before bonding specimens to brackets. An unbleached group of specimens served as controls. Shear bond strength (SBS in MPa) was measured with a universal testing machine. Adhesive Remnant Index (ARI) scores were determined after failure of bracket bonds. To measure demineralized Ca2+, four 4 x 4 mm sections from each of 15 bovine incisors were randomly distributed among 4 groups (n = 15). Specimens were stored in artificial saliva for 0 h, 24 h or 7 days after bleaching and then immersed in 37% phosphoric acid solution. After 15 s, 30 s, and 60 s, 5-ml aliquots of solution were removed for spectrophotometry. Unbleached specimens served as controls. RESULTS: Larger amounts of Ca2+ were extracted from the enamel by phosphoric acid up to 24 h after application of hydrogen peroxide, when there was also a significant decrease in bracket-enamel SBS. After 1 week, there were no changes in amounts of Ca2+ extracted, and SBS values returned towards unbleached values. CONCLUSION: Lower bracket-enamel SBS values at 24 h after bleaching are closely correlated with the larger amounts of Ca2+ extracted from the enamel.

Effects of phosphoric acid on bovine enamel bleached with carbamide peroxide.

The aim of this study was to measure the demineralization capacity of 37% phosphoric acid on bovine enamel at different time-points after bleaching with 30% carbamide peroxide. Five, 4 x 4-mm sections were obtained from the enamel of 10 bovine incisors. After applying 30% carbamide peroxide (Vivastyle) for 90 min, specimens were stored in artificial saliva for 0, 24, 72 h, or 7 d and then immersed in 37% phosphoric solution. At 15, 30, 60, 90, and 120 s, 5-ml aliquots were extracted. A control group of specimens was not bleached. Ca(2+) concentrations were measured by atomic absorption spectrophotometry. A larger amount of Ca(2+) was extracted from enamel by phosphoric acid after the application of 30% carbamide peroxide. Twenty-four hours after bleaching, significantly more Ca(2+) was extracted from bleached than from control specimens at all time-points, and this greater susceptibility to the action of the acid persisted for at least 1 wk after bleaching.

Effects on estrogen-dependent and triple negative breast cancer cells growth of Ni(II), Zn(II) and Cd(II) complexes with the Schiff base derived from pyridine-2-carboxaldehyde and 5,6-diamino-1,3-dimethyluracil explored through the renin-angiotensin system (RAS)-regulating aminopeptidases.

A series of Ni(II), Zn(II) and Cd(II) complexes with the Schiff base derived from the condensation 1:1 from pyridine-2-carboxaldehyde and 5,6-diamino-1,3-dimethyluracil (6-amino-1,3-dimethyl-5-[(pyridin-2-ylmethylidene)-amino]pyrimidine-2,4(1H,3H)-dione, DAAUPic) were synthesized and subsequently characterized by means of elemental analysis, FT-IR, NMR and nine of them by X-ray diffraction. Except the [Zn(µ-O,O'-AcO)(N5,N6,N1F-DAAUPicH-1)]2 and [Cd(O,O'-NO3)(µ-O4,(N5,N6,N1F)-DAAUPicH-1)(H2O)]2·2H2O dimers and the [Cd(µ-S,N-SCN)(N5,N6,N1F-DAAUPicH-1)]n chain-like polymer, all of them display monomeric molecular structures. The anticancer activity of compounds was also explored studying their effects on renin-angiotensin system (RAS)-regulating aminopeptidases on estrogen-dependent and triple negative breast cancer cell lines. At the concentrations used, some of the complexes showed different effects on (RAS) peptidases, which support the idea that their effects on cell growth/proliferation could be related to autocrine/paracrine regulatory functions of their corresponding peptide substrates.

A combined experimental and DFT investigation on the structure and CO-releasing properties of mono and binuclear fac-ReI(CO)3 complexes with 5-pyridin-2-ylmethylene-amino uracils.

The synthesis, structure and CO-releasing properties of a number of new tricarbonyl rhenium(i) complexes with 5-substituted-6-amino-1,3-dimethyluracils are reported and their structural features discussed on the basis of both spectral and X-ray crystallographic analyses. The 5-substituent library includes -N[double bond, length as m-dash]CH-2py (DAAUPic) and -CH[double bond, length as m-dash]N-N[double bond, length as m-dash]CH-2py (FDUHzPic) as additional metal binding components and chloride, acetonitrile or pyridine acting as ancillary ligands. The compounds have been identified by elemental analysis, NMR, MS and IR spectroscopy. In addition, [ReCl(CO)3(DAAUPic)], [Re(CO)3(FDUHzPic)py]ClO4, [Re(CO)3(FDUHzPic)py]PF6, [Re2Cl2(CO)6(FDUHzPic)] and [Re2Cl(CO)6(FDUHzPicH-1)(H2O)] structures have been solved by X-ray diffraction methods. These studies have clearly shown that the preferred coordination mode to rhenium takes place through the (N1F,N52)-pyridin-2-yl-methyleneamine moiety, the uracil coordinative availability (O4-N51 or N6-N51) being used only to bind the second metal center. The CO-releasing ability of these rhenium compounds has been investigated by the reaction with myoglobin; the corresponding studies have revealed that two of the mononuclear complexes and their related binuclear analogues are able to release CO to a moderate extent. This ability has also been theoretically assessed through a QTAIM analysis. The results, although non-conclusive, may explain somehow possible different preferences in CO releasing power after a comparison between the nature of Re-CO links in mononuclear and binuclear compounds.

Influence of the bracket on bonding and physical behavior of orthodontic resin cements.

The aim of the study is to determine the influence of the type of bracket, on bond strength, microhardness and conversion degree (CD) of four resin orthodontic cements. Micro-tensile bond strength (µTBS) test between the bracket base and the cement was carried out on glass-hour-shaped specimens (n=20). Vickers Hardness Number (VHN) and micro-Raman spectra were recorded in situ under the bracket base. Weibull distribution, ANOVA and non-parametric test were applied for data analysis (p<0.05). The highest values of ή as well as the ß Weibull parameter were obtained for metallic brackets with Transbond™ plastic brackets with the self-curing cement showing the worst performance. The CD was from 80% to 62.5%.

Silver(I)/6-hydroxyiminolumazine compounds differently modify renin-angiotensin system-regulating aminopeptidases A and N in human neuroblastoma and glioma cells.

We have described that local tissue renin-angiotensin-system (RAS) is involved in tumor growth in a rat model of experimental glioma in vivo, through the modification of their corresponding local proteolytic regulatory enzymes. Thus, we have found a time-dependent significant decrease in aminopeptidase N (APN) and a significant increase in aminopeptidase A (APA) activities concomitantly with tumor growth in tumor tissue whereas no changes were found in circulating aminopeptidase activities; we suggested that angiotensin peptides may play an essential step in both tumor infiltration and associated angiogenesis. Here we analyze in vitro the antiproliferative efficacy, apoptotic properties and effects of three new disilver complexes containing E-6-(hydroxyimino)ethyl-1,3,7-trimethyllumazine (lumazine=pteridine-2,4(1H,3H)-dione) on RAS-regulating APA and APN specific activities in human neuroblastoma and glioma cell lines NB69 and U373-MG. Disilver compounds showed cytotoxicity against both cell lines, although their potency was different for each cell type. Furthermore, NB69 cells need higher concentrations of silver complexes than U373-MG cells to obtain a 50% growth inhibition. All compounds showed apoptotic effects, with U373-MG cells being more susceptible. The three silver complexes tested also show a dose-dependent inhibitory effect on APA activity in NB69 and U373-MG cells, although U373-MG cells are more sensitive. On the contrary, none of them showed effects on APN activity in NB69 neuroblastoma cells whereas the three compounds showed a dose-dependent stimulatory effect on APN activity in U373-MG glioma cells with a similar potency. Disilver complexes show specific antitumor activity against brain tumor cells acting through the paracrine regulating system mediated by local tissue RAS.

Pilomatrix carcinoma with lymph node and pulmonary metastasis: report of a case arising on the knee.

A 58-year-old woman presented with a pilomatrix carcinoma on the right knee. The tumor developed at the site of a previous lesion that had been present since she was 30 years old. Histologic study showed the presence of basaloid cells with numerous atypical mitoses, shadow cells, and calcification. After several surgical excisions, the tumor mass infiltrated the subcutaneous tissue, muscle, and bone, resulting in inguinal lymph node and pulmonary metastasis. We also review the literature and comment on the histopathologic differences from other cutaneous tumors.