Evaluation of Different Techniques and Materials for Filling in 3-dimensional Printed Teeth Replicas with Perforating Internal Resorption by Means of Micro-Computed Tomography.

INTRODUCTION: The aim of this study was to evaluate the filling ability of 2 obturation techniques in 3-dimensional (3D) printed teeth with perforating internal resorption (PIR). METHODS: A maxillary central incisor was instrumented and scanned by micro-computed tomographic (micro-CT) imaging. The 3D model was exported in the stereolithographic format and, with the aid of OrtogOnBlender software (Cícero Moraes, Sinop, SP, Brazil), a PIR in the middle third of the root canal was designed. Thirty-two replicas were printed in surgical resin and distributed into 4 groups (n = 8) according to the obturation technique and the material used: 2 groups used the hybrid technique, 1 with Bio-C Sealer (BCS; Angelus, Londrina, PR, Brazil)/gutta-percha (GP; VDW GmbH, Munich, Germany) + Bio-C Repair (BCR; Angelus, Londrina, PR, Brazil) and the other with BioRoot (BR; Septodont, Saint Maur des Fosses, France)/gutta-percha (GP) + Biodentine (BD; Septodont, Saint Maur des Fosses, France), and 2 groups used the incremental technique, 1 with BCR and the other with BD. Postobturation micro-CT imaging was performed to measure the percentage volume of voids and laser confocal microscopy to measure the surface roughness (µm) of the repair cements. Data were compared using analysis of variance and Kruskal-Wallis tests. RESULTS: Regarding the filling volume in the apical third, the BCS/GP + BCR (89.70 ± 5.15), BR/GP + BD (87.70 ± 8.43), and BCR (84.20 ± 9.00) groups showed the highest percentages compared with the BD group (69.70 ± 6.88) (P < .05). In the area of internal resorption, the BCS/GP + BCR (96.00 ± 2.64) and BCR (95.30 ± 2.93) groups showed the highest percentages compared with the BR/GP + BD group (91.50 ± 1.35) (P < .05). The BD group showed intermediate values that were sometimes similar to the BCS/GP + BCR and BCR groups and similar to the BR/GP + BD group (P > .05). Regarding the quality of the filling in the perforation area, the BCR group showed better results compared with the BD group (P < .001). Regarding roughness, the BCR group (1.66 ± 0.65) showed lower surface roughness compared with the BD group (2.51 ± 0.89) (P < .05). CONCLUSIONS: The capacity and quality of the filling in teeth with PIR were superior with the incremental technique with BCR and the hybrid technique with BCS/GP + BCR.

Beyond ecology: ecosystem restoration as a process for social-ecological transformation.

Ecosystem restoration conventionally focuses on ecological targets. However, while ecological targets are crucial to mobilizing political, social, and financial capital, they do not encapsulate the need to: integrate social, economic, and ecological dimensions and systems approaches; reconcile global targets and local objectives; and measure the rate of progress toward multiple and synergistic goals. Restoration is better conceived as an inclusive social-ecological process that integrates diverse values, practices, knowledge, and restoration objectives across temporal and spatial scales and stakeholder groups. Taking a more process-based approach will ultimately enable greater social-ecological transformation, greater restoration effectiveness, and more long-lasting benefits to people and nature across time and place.

Can Carbodiimide (EDC) and Chitosan Cross-linking Agents Effect the Longevity of Fiberglass Posts Luted with Different Types of Composite Cements to Root Dentin?

PURPOSE: To evaluate the effect of carbodiimide (EDC) and chitosan (CHI) on the enzymatic activity (EA) and bond strength (BS) of different composite cements to root dentin. MATERIALS AND METHODS: Ninety (90) maxillary canines were sectioned, standardizing the length of the roots. The roots were endodontically treated, prepared, divided into 3 groups according to dentin treatment (distilled water [DW], CHI 0.2 wt%, or EDC 0.5M), and further subdivided into 3 subgroups according to composite cement (RelyX ARC [3M Oral Care], Panavia F 2.0 [Kuraray Noritaki], or RelyX U200 [3M Oral Care]). Of the slices obtained by sectioning, the most cervical of each third were subjected to a push-out test and the most apical were subjected to in-situ zymography. Half of the slices were analyzed immediately, and the other half after 6 months. The results were analyzed with ANOVA or the chi-squared test. RESULTS: RelyX ARC showed higher BS associated with CHI, while RelyX U200 showed higher BS associated with EDC (p = 0.044). For Panavia F 2.0, the treatment did not influence BS (p > 0.05). For the cervical and middle thirds, no differences were observed between the cements, while the apical third revealed higher BS for RelyX U200 (p < 0.001). The highest percentage of adhesive-to-dentin failures was observed for Panavia F 2.0. EDC showed the lowest percentage of adhesive-to-dentin failures. According to zymographic analysis, DW and CHI showed greater fluorescence for RelyX ARC, while EDC exhibited the lowest fluorescence of all cements (p > 0.05). CONCLUSION: The different mechanisms of action of solutions for pre-treatment of intraradicular dentin yielded different results depending on the adhesive used. EDC resulted in higher bond strength and higher enzyme inhibition for RelyX U200, while the treatment with chitosan resulted in higher bond strength and lower enzymatic activity for RelyX ARC. Although EDC and chitosan treatments did not influence the bond strength for Panavia F 2.0, both resulted in higher enzyme inhibition for this composite cement.

Operando Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy of the NO Reduction Reaction over Rhodium-Based Catalysts.

Operando shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) with on-line mass spectrometry (MS) has been used to investigate the surface species, such as NO, NOH, NO2 , N2 O, and reaction products of the NO reduction reaction with CO and H2 over supported Rh-based catalysts in the form of catalyst extrudates. By correlating surface intermediates and reaction products, new insights in the reaction mechanism could be obtained. Upon applying different reaction conditions (i. e., H2 or CO), the selectivity of the catalytic reaction could be tuned towards the formation of N2 . Furthermore, in the absence of Rh, no reaction products were detected. The importance of the operando SHINERS as a surface-sensitive characterization technique in the field of heterogeneous catalysis provides routes towards a better understanding of catalytic performance.

The glucoamylase from Aspergillus wentii: Purification and characterization.

This study describes for the first time the purification and characterization of a glucoamylase from Aspergillus wentii (strain PG18), a species of the Aspergillus genus Cremei section. Maximum enzyme production (∼3.5 U/ml) was obtained in submerged culture (72 h) with starch as the carbon source, at 25°C, and with orbital agitation (100 rpm). The enzyme was purified with one-step molecular exclusion chromatography. The 86 kDa purified enzyme hydrolyzed starch in a zymogram and had activity against p-nitrophenyl α- d-glucopyranoside. The optimal enzyme pH and temperature were 5.0 and 60°C (at pH 5.0), respectively. The Tm of the purified enzyme was 60°C, at pH 7.0. The purified glucoamylase had a KM for starch of 1.4 mg/ml and a Vmax of 0.057 mg/min of hydrolyzed starch. Molybdenum activated the purified enzyme, and sodium dodecyl sulfate inhibited it. A thin layer chromatography analysis revealed glucose as the enzyme's main starch hydrolysis product. An enzyme's peptide sequence was obtained by mass spectrometry and used to retrieve a glucoamylase within the annotated genome of A. wentii v1.0. An in silico structural model revealed a N-terminal glycosyl hydrolases family 15 (GH15) domain, which is ligated by a linker to a C-terminal carbohydrate-binding module (CBM) from the CBM20 family.

Bioactive Male-Produced Volatiles from Anastrepha obliqua and their Role in Attraction of Conspecific Females.

The study of insect semiochemicals, especially pheromones, is of fundamental importance for the development of strategies for controlling agricultural pests. In this study, volatile compounds involved in the communication between males and females of the fruit fly, Anastrepha obliqua (Diptera: Tephritidae), for mating purposes were characterized to develop attractant formulations for females of this species. Extracts containing volatile compounds released by males of A. obliqua were obtained by the dynamic headspace technique and analyzed by gas chromatography coupled with an electroantennographic detector (GC-EAD) and gas chromatography coupled with mass spectrometry (GC-MS). Twenty-one volatile compounds were identified in the aeration extracts of males. Five of them caused EAD responses from the antennae of females: 1-heptanol, linalool, (Z)-3-nonen-1-ol, (E,Z)-3,6-nonadien-1-ol, and (Z,E)-α-farnesene. Six synthetic mixtures of these compounds, including the five-component blend and all possible four-component blends, were formulated in a biopolymer and used in behavioral bioassays conducted in the laboratory arena with conspecific virgin females. One blend of 1-heptanol, linalool, (Z)-3-nonen-1-ol, and (Z,E)-α-farnesene attracted more females than the collection of volatiles from virgin males used as control. The other mixtures were as attractive to A. obliqua females as the control treatment. This study indicates potential for use of these compounds in monitoring and control strategies for this pest.

Addition of either gastric lipase or cholesterol esterase to improve both ß-cryptoxanthin ester hydrolysis and micellarization during in vitro digestion of fruit pulps.

Using the INFOGEST in vitro digestion protocol adapted to carotenoids, the impact of additional rabbit gastric lipase (RGL) on the hydrolysis extent of ß-cryptoxanthin esters was evaluated for the first time, and compared with the addition of porcine cholesterol esterase (CEL). Both the modifications increased the hydrolysis of (all-E)-ß-cryptoxanthin esters from mandarin and peach pulps, although the outcomes were different. Addition of RGL consistently increased the average hydrolysis extent from 55.2% to 59.5% in mandarin pulp and from 22.7% to 48.8% in peach pulp (p < 0.05). The addition of CEL produced lower hydrolysis extents, i.e., 58.5% in mandarin (not statistically significant) and 28.4% in peach (p < 0.05), compared to those obtained with RGL. The hydrolysis extent positively correlated with the carotenoid ester concentration in both matrices. Bioaccessibility values were higher in mandarin pulp (range 32-34%) compared to those in peach pulp (range 16-21%), and were associated with the hydrolysis extent of the carotenoid esters during digestion. Addition of RGL and CEL produced no significant (p < 0.05) effect on the overall carotenoid bioaccessibility values of mandarin, while positively affected those in peach. Altogether these results corroborate that the hydrolysis extent of xanthophyll esters limits bioaccessibility. Additionally, hydrophobicity of the carotenoid inversely correlates with micellarization, as free (all-E)-xanthophylls micellarized in a higher extent compared to (all-E)-ß-carotene and xanthophyll esters. The new information of our results is that the addition of rabbit gastric lipase substantially contributes to the hydrolysis of ß-cryptoxanthin esters from fruit pulps, and consequently, to increase carotenoid bioaccessibility, being even more effective than CEL.

HPLC-PDA-MS/MS as a strategy to characterize and quantify natural pigments from microalgae.

Interest in pigment composition of microalgae species is growing as new natural pigments sources are being sought. However, we still have a limited number of species of microalgae exploited to obtain these compounds. Considering these facts, the detailed composition of carotenoids and chlorophylls of two species of green microalgae (Chlorella sorokiniana and Scenedesmus bijuga) were determined for the first time by high-performance liquid chromatography coupled to diode array and mass spectrometry detectors (HPLC-PDA-MS/MS). A total of 17 different carotenoids were separated in all the extracts. Most of the carotenoids present in the two microalgae species are xanthophylls. C. sorokiniana presented 11 carotenoids (1408.46 µg g-1), and S. bijuga showed 16 carotenoids (1195.75 µg g-1). The main carotenoids detected in the two microalgae were all-trans-lutein and all-trans-ß-carotene. All-trans-lutein was substantially higher in C. sorokiniana (59.01%), whereas all-trans-ß-carotene was detected in higher quantitative values in S. bijuga (13.88%). Seven chlorophyll compounds were identified in both strains with different proportions in each species. Concentrations of chlorophyll representing 7.6% and 10.2% of the composition of the compounds present in the biomass of C. sorokiniana and S. bijuga, respectively. Relevant chlorophyll compounds are reported for the first time in these strains. The data obtained provide significant insights for microalgae pigment composition databases.

Carotenoid biosynthesis and quality characteristics of new hybrids between tangor (Citrus reticulata x C. sinensis) cv. 'Murcott' and sweet orange (C. sinensis) cv. 'Pêra'.

Phenotypic characteristics, as well as the relation between carotenoid accumulation and gene expression during ripening were determined in fruits of five new hybrids between tangor cv. 'Murcott' and sweet orange cv. 'Pêra'. The genotypes were classified into the orange-like group, showing mainly epoxycarotenoids, oval fruit shape and yellowish color, or in the mandarin-like group, showing mainly ß-cryptoxanthin, flattened shape and deep-orange coloration; although some hybrids presented intermediate characteristics. The diversity in carotenoid composition of hybrids and genitors were mostly explained by patterns of gene expression. High carotenoid (250-426 µg/g dry weight [dw]) and ß-cryptoxanthin (81-125 µg/g dw) contents, observed in the mandarin-like group, were generally associated with high expression of upstream genes (GGPPS1, PSY, PDS). On the other hand, low expression/repression of these genes and high expression of downstream genes (BCHX and ZEP) were associated with low carotenoid (~158 µg/g dw) and ß-cryptoxanthin (5-22 µg/g dw) contents and epoxycarotenoid accumulation, as occurred in the orange-like group. Breeding experiments resulted in hybrids with outstanding higher carotenoid contents than both genitors (up to 426 µg/g dw versus 158-250 µg/g dw in genitors), which was attributed to transgressive segregation. Differences among genotypes have great impact on commercial fruit quality and potential health benefits, such as the provitamin A content.

Carotenoid profile of three microalgae/cyanobacteria species with peroxyl radical scavenger capacity.

Carotenoids from cyanobacteria Aphanothece microscopica Nageli and green microalgae Chlorella vulgaris and Scenedesmus obliquus were identified. The total carotenoid content, based on dry weight of biomass, of A. microscopica Nägeli, C. vulgaris and S. obliquus were 1398.88µg/g, 1977.02µg/g and 2650.70µg/g, respectively. A total of 23 different carotenoids were separated in all the extracts, the major ones being all-trans-ß-carotene (29.3%) and all-trans-lutein (28.1%) in Scenedesmus; all-trans-echinenone (22.8%) and all-trans-ß-carotene (17.7%) in Chlorella; all-trans-echinenone (28.3%) and all-trans-ß-carotene (26.2%) in Aphanothece. The carotenoid extracts were shown to be a potent scavenger of peroxyl radical, with values of 31.1 (Chlorella), 14.0 (Scenedesmus) and 7.3 (Aphanothece) times more potent than α-tocopherol.

Synthesis and Charaterization of Silica-Based Aldehyde Chitosan Hybrid Material for Biodiesel Purification.

This study concerns the development and charaterization of Silica-based aldehyde Chitosan hybrid material as an adsorbent for biodiesel purification. This biocomposite was prepared by sol-gel route and oxidation with periodate, and then characterized. FTIR experiments showed that the hybrid formed presents absorption bands similar to those of Chitosan-Silica, with the exception of the vibrations at 1480 cm-1 and 1570 cm-1 attributed to the symmetrical angular deformation in the N-H plane, and possess large N2 Brunauer-Emmett-Teller (BET) surface areas. Thermogravimetric analysis (TG) and scanning electron microscopy (SEM) was also carried out. Adsorption studies of bioadsorbents involving the analysis of free glycerol, soap, acidity, diglycerides, triglycerides, and fluorescence spectroscopy showed that silica-based aldehyde chitosan has a good affinity for glycerol and a good purification process.

Carotenoid esters in foods - A review and practical directions on analysis and occurrence.

Carotenoids are naturally found in both free form and esterified with fatty acids in most fruits and some vegetables; however, up to now the great majority of studies presents data on carotenoid composition only after saponification. The reasons for this approach are that a single xanthophyll can be esterified with several different fatty acids, generating a great number of different compounds with similar chemical and structural characteristics, thus, increasing the complexity of analysis compared to the respective saponified extract. This means that since UV/Vis spectrum does not change due to esterification, differentiation between free and acylated xanthophylls is dependent at least on elution order and mass spectrometry (MS) features. The presence of interfering compounds, especially triacylglycerides (TAGs), in the non-saponified extract of carotenoids can also impair carotenoid ester analyses by MS due to high background noise and ionization suppression since TAGs can be present in much higher concentrations than the carotenoid esters. This leads to the need of development of new and effective clean-up procedures to remove the potential interferents. In addition, only few standards of xanthophyll esters are commercially available, making identification and quantification of such compounds even more difficult. Xanthophyll esterification may also alter some properties of these compounds, including solubility, thermostability and bioavailability. Considering that commonly consumed foods are dietary sources of xanthophyll esters and that it is the actual form of ingestion of such compounds, an increasing interest on the native carotenoid composition of foods is observed nowadays. This review presents a compilation of the current available information about xanthophyll ester analyses and occurrence and a practical guide for extraction, pre-chromatographic procedures, separation and identification by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Kinetic modeling to study the quality of tambaqui (Colossoma macropomum) sous vide during storage at different temperatures.

This study aimed to assess the changes in quality of tambaqui sous vide during refrigerated storage using degradation kinetics. Tambaqui sous vide was prepared and stored at three temperatures (1, 4, 10 °C). The microorganism counts and the physicochemical analyses were analyzed every three days. The results obtained were fitted to the Labuza models and by Arrhenius equation. The results of the microbiological and physicochemical analyses obtained better fits to the zero-order model. The Arrhenius equation better fit to the velocity constants of the zero-order model, which showed that the changes in the values of attributes are related to temperature. Higher Ea values were found for the microorganism counts than for the physicochemical parameters, which proves the greater dependency of microorganisms on variations in temperature. The assessment of changes in quality based on temperature allows the storage conditions to be optimized.

Hongos productores de micotoxinas asociados a hierbas medicinales en la Ciudad de São Paulo, Brasil / Mould and mycotoxins associated in medicinal plants in São Paulo, Brazil

Antecedentes: la fitoterapia es una de las más antiguas prácticas utilizadas por la humanidad. Hasta mediados del siglo XIX, cuando se introdujeron los medicamentos, la formulación de estos generalmente era basada en plantas medicinales. Objetivos: Determinar la micobiota y los niveles de aflatoxinas originadas de Aspergillus sección Flavi aislados de las 50 muestras de medicamentos fitoterápicos comercializados actualmente en la ciudad de São Paulo, Brasil. Métodos: Cincuenta (50) muestras de medicamentos fitoterápicos en la forma de hojas (té-25) y cápsulas (25) fueron colectadas de agosto de 2000 a julio de 2001. Los hongos filamentosos aislados fueron identificados al nivel de género de acuerdo con las características morfológicas y criterios taxonómicos. El análisis de aflatoxinas fue realizada por cromatografía de capa fina (TLC). Resultados: El análisis microbiológico mostró que 41 (82 por ciento) de los medicamentos fitoterápicos presentaron un crecimiento fúngico sobre las 100 UFC/g. Un total de 106 especies de seis diferentes géneros fueron aislados (Aspergillus, Penicillium, Mucor, Rhizopus y Alternaria). El género Aspergillus fue el predominante (60.5 por ciento) seguido por Penicillium (20,0 por ciento). Aspergillus niger (30 por ciento) A. flavus (22 por ciento), A. fumigatus (6,5 por ciento) y A. parasiticus fueron las especies de Aspergillus identificadas. Se observó que 13 (56,5 por ciento), de los 23 A. flavus aislados y dos aislados de A. parasiticus produjeron aflatoxinas. Conclusiones: La contaminación observada en la mayoría de los productos y el alto nivel de cepas productoras de aflatoxinas justifica un análisis más cuidadoso de los medicamentos fitoterápicos comercializados y la aplicación de leyes más rigurosas son necesarias para garantizar la calidad de los productos.

Background: phytotherapy is one of the most ancient practices used by humanity. In Antiquity until the middle of the XIX century, when chemotherapeutic drugs were introduced, formulation of medicines was usually based on medicinal plants. Objective: To determine mycobiota and levels of Aspergillus section Flavi aflatoxins isolated from 50 samples of phytotherapeutic remedies currently commercialized in São Paulo, Brazil. Methods: Fifty (50) samples of phytotherapeutic remedies in the form of leaves (teas-25) and powders (capsules-25) were collected from August 2000 to July 2001. Filamentous fungi isolates were identified at the genera level in accordance with morphological characteristics and taxonomic criteria. Aflatoxins were performed by Thin-layer chromatography (TLC). Results: The microbiological analysis showed that 41 (82 percent) of phytotherapeutic remedies presented a fungal growth over 100 CFU/g. A total of 106 species of six different genera were isolated (Aspergillus, Penicillium, Mucor, Rhizopus and Alternaria). The genus Aspergillus was the predominant (60.5 percent) followed by Penicillium genus (20.0 percent). Aspergillus niger (30 percent) A. flavus (22 percent), A. fumigatus (6.5 percent) and A. parasiticus were the species of Aspergillus identified. It was observed that 13 (56.5 percent) of 23 A. flavus isolates and two A. parasiticus isolates produced aflatoxins. Conclusions: The contamination observed in most products and the high level of aflatoxigenic strains justify the concern regarding the execution of more careful analyzes of the commercialized phytotherapeutic remedies and the application of more rigorous laws that may warrant the quality of these products.

Composition by LC-MS/MS of New Carotenoid Esters in Mango and Citrus.

Interest in the composition of carotenoid esters of fruits is growing because esterification may affect their bioavailability. Thus, the aim was to provide a detailed identification of carotenoid esters in citrus and mango. Orange cv. 'Valencia' and cv. 'Pera' presented 9 free carotenoids, 38 monoesters, and 60 diesters. Violaxanthin and luteoxanthin derivatives were the major ones, followed by antheraxanthin, lutein, zeaxanthin, ß-cryptoxanthin, and zeinoxanthin esters, many of them reported for the first time in orange pulp. The carotenoid ester composition of tangor cv. 'Murcott', reported for the first time, showed 8 free carotenoids, 34 monoesters, and 33 diesters, with ß-cryptoxanthin esters as major compounds, followed by violaxanthin and zeaxanthin esters. In citrus, carotenoids were acylated mainly with capric, lauric, myristic, myristoleic, palmitic, palmitoleic, and oleic acids. In mango, 5 free carotenoids, 2 monoesters, and 19 diesters were identified, from which many violaxanthin and neoxanthin esters were reported for the first time.

Evaluation of a Portable Microchip Electrophoresis Fluorescence Detection System for the Analysis of Amino Acid Neurotransmitters in Brain Dialysis Samples.

A portable fluorescence detection system for use with microchip electrophoresis was developed and compared to a benchtop system. Using this system, six neuroactive amines commonly found in brain dialysate (arginine, citrulline, taurine, histamine, glutamate, and aspartate) were derivatized offline with naphthalene-2,3-dicarboxaldehyde/cyanide, separated electrophoretically, and detected by fluorescence. The limits of detection for the analytes of interest were 50 - 250 nM for the benchtop system and 250 nM - 1.3 µM for the portable system, both of which were adequate for most analyte detection in brain microdialysis samples. The portable system was then demonstrated for the detection of the same six amines in a rat brain microdialysis sample.

Mesenchymal Hamartoma of the Liver in an Infant With Beckwith-Wiedemann Syndrome: A Rare Condition Mimicking Hepatoblastoma.

Patients with Beckwith-Wiedemann syndrome (BWS) are known to be at an increased risk for childhood malignancies, particularly Wilms tumor and hepatoblastoma. We report a case of genetically confirmed BWS in a 5-month-old girl who presented with a 9.5-cm abdominal mass associated with elevated α-fetoprotein levels. The clinical impression was strongly suggestive of hepatoblastoma. Histologic examination of the surgically excised mass revealed mesenchymal hamartoma of the liver (MHL), a benign hepatic neoplasm.

Evaluation of in-channel amperometric detection using a dual-channel microchip electrophoresis device and a two-electrode potentiostat for reverse polarity separations.

In-channel amperometric detection combined with dual-channel microchip electrophoresis is evaluated using a two-electrode isolated potentiostat for reverse polarity separations. The device consists of two separate channels with the working and reference electrodes placed at identical positions relative to the end of the channel, enabling noise subtraction. In previous reports of this configuration, normal polarity and a three-electrode detection system were used. In the two-electrode detection system described here, the electrode in the reference channel acts as both the counter and reference. The effect of electrode placement in the channels on noise and detector response was investigated using nitrite, tyrosine, and hydrogen peroxide as model compounds. The effects of electrode material and size and type of reference electrode on noise and the potential shift of hydrodynamic voltammograms for the model compounds were determined. In addition, the performance of two- and three-electrode configurations using Pt and Ag/AgCl reference electrodes was compared. Although the signal was attenuated with the Pt reference, the noise was also significantly reduced. It was found that lower LOD were obtained for all three compounds with the dual-channel configuration compared to single-channel, in-channel detection. The dual-channel method was then used for the detection of nitrite in a dermal microdialysis sample obtained from a sheep following nitroglycerin administration.

Molecular mechanism of action of 2-ferrocenyl-1,1-diphenylbut-1-ene on HL-60 leukemia cells.

The aim of this work was to investigate the mechanism of action of 2-ferrocenyl-1,1-diphenylbut-1-ene (1) on HL-60 human leukemia cells. While inactive against noncancerous cells, 1 provoked a concentration-dependent decrease in viable tumor cells, primarily via apoptosis, as evidenced by analysis of cell morphology, activation of caspases 3 and 7, increased DNA fragmentation, and externalization of phosphatidylserine. Necrosis was observed only at the highest tested concentration (4 µM). Compound 1 interfered with the cell cycle, causing an accumulation of cells in the G1 /G0 phase. Interaction of 1 with dsDNA and ssDNA was observed by differential pulse voltammetry and confirmed by hyperchromicity in the UV/Vis spectra of dsDNA, with an interaction constant of 2×10(4) M(-1). Both the organic analogue 1,1,2-triphenylbut-1-ene (2) and ferrocene were inactive against cancer and noncancer cell lines and did not react with DNA. These results reinforce the idea that the hybrid strategy of conjugating ferrocene to the structure of tamoxifen derivatives is advantageous in finding new substances with antineoplastic activity.