Effects of ethyl-cyanoacrylate and octyl-cyanoacrylate on experimental corneal lesions in rabbits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fixation of autogenous bone grafts with ethyl-cyanoacrylate glue or titanium screws in the calvaria of rabbits

This study compared the fixation of autogenous onlay bone grafts with cyanoacrylate glue (Super Bonder) and with titanium screws. Twenty rabbits underwent bilateral parietal ostectomies. Bone segments were fixed anteriorly to the resulting bone defect. In group I, the grafts were fixed with 4 min long, 1.5 mm diameter screws; in group II, adhesive was used. The animals were killed after 5, 15, 30, 60 and 120 days. Histomorphometric analysis was used to quantify the maintenance of the graft area. Discrete areas of inflammatory reaction were seen in both groups after 5 days and for group II after 15 days. After 30 days, new bone formation was seen at the interface of the grafts. After 120 days, the graft was incorporated into the host bed in group I and partially incorporated in group II. There was a significant statistical difference regarding the mean graft areas between 15 and 120 days (p < 0.001) and between fixation methods (p < 0.002). Fixation with adhesive promoted a significantly greater area of bone graft than screw fixation, independent of time period. The adhesive was biocompatible, presented similar stability to the screw and maintained the bone area, although there was a delay in graft incorporation.

Utilization of Ethyl Cyanoacrylate and 2-Octyl Cyanoacrylate Adhesives for Autogenous Bone Graft Fixation: Histomorphometric Study in Rats

The present study analyzes the repair process of autogenous bone graft in a block fixed with ethyl cyanoacrylate and 2-octyl cyanoacrylate adhesives in rat calvaria. Forty-eight rats, divided into 3 groups, received round osteotomies at the right parietal bone for the attainment of autogenous bone graft fragment, which was fixed at the opposite side to the donor site with ethyl cyanoacrylate (ethyl group) and 2-octyl cyanoacrylate (octyl group) adhesives. In the control group, bone fragment was only juxtaposed at the parietal bone surface without any fixation material. The animals were euthanized after 10 and 60 postoperative days. The calvariae were processed in a laboratory for the attainment of slides stained through the hematoxylin and eosin technique for histological and histometric analysis. The qualitative analysis showed a discrete inflammatory infiltrate in the control group and moderate inflammatory infiltrate in the ethyl and octyl groups at the 10-day period, which remained at the 60-day period, mainly in the octyl group. The bone fragment remained bonded to the recipient site through the adhesive, but graft incorporation was not observed in any of the specimens. Resorption was higher in the octyl group followed by the ethyl and control groups, both at the 10-and 60-day periods, but with no statistical significance (P < .05). Although promoting graft fixation and its maintenance at the recipient site, both studied adhesives did not allow the graft incorporation, producing a localized and discrete inflammatory reaction, which persisted at 60 days, being more intense in the octyl cyanoacrylate group.

Histomorphometric analysis of the repair process of autogenous bone grafts fixed at rat calvaria with cyanoacrylate

Objective: The purpose of this study was to perform histological and histometric analyses of the repair process of autogenous bone grafts fixed at rat calvaria with ethyl-cyanoacrylate adhesive. Material and Methods: Thirty-two rats were divided into two groups (n=16), Group I - Control and Group II - Adhesive. Osteotomies were made at the right parietal bone for graft obtainment using a 4-mm-diameter trephine drill. Then, the bone segments were fixed with the adhesive in the parietal region of the opposite side to the donor site. After 10 and 30 days, 8 animals of each group were euthanized and the calvarias were laboratorially processed for obtaining hematoxylin and eosin-stained slides for histological and histometric analyses. Results: An intense inflammatory reaction was observed at the 10-day period. At 30 days, this reaction was less intense, despite the presence of adhesive at the recipient-site/graft interface. Graft incorporation to the recipient site was observed only at the control group, which maintained the highest graft size at 10 and 30 days. Conclusions: Although the fragment was stable, the presence of adhesive in Group II did not allow graft incorporation to the recipient site, determining a localized, discrete and persistent inflammatory reaction.

Emprego do etil-cianoacrilato ou do octil-cianoacrilato no preenchimento de lesões corneais, após ceratectomia lamelar em coelhos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fixação do enxerto ósseo autógeno em bloco com adesivos a base de cianoacrilato ou parafuso de titânio: estudo histológico em coelhos

Pós-graduação em Odontologia - FOA

Estudo do processo de reparo de enxerto ósseo em bloco submetido ao recobrimento com etil-cianoacrilato: análise histométrica e imunoistoquímica em ratos

Pós-graduação em Odontologia - FOA

Influence of apical foramen lateral opening and file size on cemental canal instrumentation

Since instrumentation of the apical foramen has been suggested for cleaning and disinfection of the cemental canal, selection of the file size and position of the apical foramen have challenging steps. This study analyzed the influence of apical foramen lateral opening and file size can exert on cemental canal instrumentation. Thirty-four human maxillary central incisors were divided in two groups: Group 1 (n=17), without flaring, and Group 2 (n=17), with flaring with LA Axxess burs. K-files of increasing diameters were progressively inserted into the canal until binding at the apical foramen was achieved and tips were visible and bonded with ethyl cyanoacrylate adhesive. Roots/files set were cross-sectioned 5 mm from the apex. Apices were examined by scanning electron microscopy at ×140 and digital images were captured. Data were analyzed statistically by Student’s t test and Fisher’s exact test at 5% significance level. SEM micrographs showed that 19 (56%) apical foramina emerged laterally to the root apex, whereas 15 (44%) coincided with it. Significantly more difficulty to reach the apical foramen was noted in Group 2. Results suggest that the larger the foraminal file size, the more difficult the apical foramen instrumentation may be in laterally emerged cemental canals.

Ethyl-eicosapentaenoic acid in first-episode psychosis : a 1H-MRS study

Ethyl-eicosapentaenoic acid (E-EPA) is an omega-3 fatty acid that has been used in a range of neuropsychiatric conditions with some benefits. However, its mechanism of action is unknown. Here, we investigate its effects on in vivo brain metabolism in first-episode psychosis (FEP). Proton magnetic resonance spectroscopy at 3 T was performed in the temporal lobes of 24 FEP patients before and after 12 weeks of treatment in the context of a larger double-blind, placebo-controlled E-EPA augmentation study. Treatment group effects for glutathione (F1,12=6.1, p=0.03), and a hemisphere-by-group interaction for glutamine/glutamate (F1,20=4.4, p=0.049) were found. Glutathione increased bilaterally and glutamate/glutamine increased in the left hemisphere following E-EPA administration. Improvement in negative symptoms correlated with metabolic brain changes, particularly glutathione (r=-0.57). These results suggest that E-EPA augmentation alters glutathione availability and modulates the glutamine/glutamate cycle in early psychosis, with some of the metabolic brain changes being correlated with negative symptom improvement. Larger confirmatory studies of these postulated metabolic brain effects of E-EPA are warranted.

Simultaneous kinetic-spectrophotometric determination of maltol and ethyl maltol in food samples by using chemometrics

A fast and accurate procedure has been researched and developed for the simultaneous determination of maltol and ethyl maltol, based on their reaction with iron(III) in the presence of o-phenanthroline in sulfuric acid medium. This reaction was the basis for an indirect kinetic spectrophotometric method, which followed the development of the pink ferroin product (λmax = 524 nm). The kinetic data were collected in the 370–900 nm range over 0–30 s. The optimized method indicates that individual analytes followed Beer’s law in the concentration range of 4.0–76.0 mg L−1 for both maltol and ethyl maltol. The LOD values of 1.6 mg L−1 for maltol and 1.4 mg L−1 for ethyl maltol agree well with those obtained by the alternative high performance liquid chromatography with ultraviolet detection (HPLC-UV). Three chemometrics methods, principal component regression (PCR), partial least squares (PLS) and principal component analysis–radial basis function–artificial neural networks (PC–RBF–ANN), were used to resolve the measured data with small kinetic differences between the two analytes as reflected by the development of the pink ferroin product. All three performed satisfactorily in the case of the synthetic verification samples, and in their application for the prediction of the analytes in several food products. The figures of merit for the analytes based on the multivariate models agreed well with those from the alternative HPLC-UV method involving the same samples.

Hydrogen bonding in the water stabilized structure of the modified unsymmetrically substituted viologen chromophore, N-ethyl-N'-(2-phosphonomethyl)-4,4'-bipyridylium dichloride

The crystal structure of the modified unsymmetrically N, N'-substituted viologen chromophore, N-ethyl- N'-(2-phosphonoethyl)-4, 4'-bipyridinium dichloride 0.75 hydrate. (1) has been determined. Crystals are triclinic, space group P-1 with Z = 2 in a cell with a = 7.2550(1), b = 13.2038(5), c = 18.5752(7) Å, α = 86.495(3), β = 83.527(2), γ = 88.921(2)o. The two independent but pseudo-symmetrically related cations in the asymmetric unit form one-dimensional hydrogen-bonded chains through short homomeric phosphonic acid O-H...O links [2.455(4), 2.464(4)A] while two of the chloride anions are similarly strongly linked to phosphonic acid groups [O-H…Cl, 2.889(4), 2.896(4)Å]. The other two chloride anions together with the two water molecules of solvation (one with partial occupancy) form unusual cyclic hydrogen-bonded bis(Cl...water) dianion units which lie between the layers of bipyridylium rings of the cation chain structures with which they are weakly associated.

The undesirable acetylation of cellulose by the acetate ion of 1-ethyl-3-methylimidazolium acetate

The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc) is considered to be an inert solvent of cellulose and lignocellulosic biomass. Acetylation (1.7 % mol, or DS 0.017) of cellulose after dissolution in [C2mim]OAc (150 °C for 20 min), is demonstrated by compositional analysis, FTIR analysis and 13C NMR spectroscopy (in [C2min]OAc with 13C enriched acetate). This acetylation, in the absence of added acylating agents, has not been reported before and may limit [C2mim]OAc utility in industrial scale biomass processing, even at this low extent. For example, cellulose acetylation may contribute to IL loss in processes where the IL is recovered and reused and inhibit enzyme saccharification of cellulose in lignocellulosic biofuel production processes based on saccharification and fermentation.

Cyanoacrylate glue as an alternative mounting medium for resin-embedded semithin sections

Commercially available generic Superglue (cyanoacrylate glue) can be used as an alternative mounting medium for stained resin-embedded semithin sections. It is colourless and contains a volatile, quick-setting solvent that produces permanent mounts of semithin sections for immediate inspection under the light microscope. Here, we compare the use of cyanoacrylate glue for mounting semithin sections with classical dibutyl phthalate xylene (DPX) in terms of practical usefulness, effectiveness and the quality of the final microscopic image.