Penetrability of AH plus and MTA fillapex after endodontic treatment and retreatment: A confocal laser scanning microscopy study

The aim of the study was to assess the penetrability of two endodontic sealers (AH Plus and MTA Fillapex) into dentinal tubules, submitted to endodontic treatment and subsequently to endodontic retreatment. Thirty ex vivo incisors were prepared using ProTaper rotary system up to F3 instrument and divided in three groups according to the endodontic sealer used for root canal filling: AH Plus (AHP), MTA Fillapex (MTAF), and control group (CG) without using EDTA previously to the root canal filling. Rhodamine B dye (red) was incorporated to the sealers in order to provide the fluorescence which will enable confocal laser scanning microscopy (CLSM) assessment. All specimens were filled with gutta‐percha cones using the lateral compaction technique. The specimens were submitted to endodontic retreatment using ProTaper Retreatment system, re‐prepared up to F5 instruments and filled with gutta‐percha cones and the same sealer used during endodontic retreatment. Fluorescein dye (green) was incorporated to the sealer in order to distinguish from the first filling. The roots were sectioned 2 mm from the apex and assessed by CLSM. No difference was found between the two experimental groups (P > 0.05). On the other hand, in the control group the sealers were not capable to penetrate into dentinal tubules after endodontic treatment (P > 0.05). In retreatment cases, none of the sealers were able to penetrate into dentin tubules. It can be concluded that sealer penetrability is high during endodontic treatment. However, MTA Fillapex and AH Plus do not penetrate into dentinal tubules after endodontic retreatment. Microsc. Res. Tech. 77:467–471, 2014. © 2014 Wiley Periodicals, Inc.     

Crystallization and microstructure of metastable water quenched nanostructured 8 mol% yttria-stabilized zirconia using the solution precursor plasma spray method

A t′ tetragonally structured metastable 8 mol% yttria-stabilized zirconia (8 mol% YSZ) nanomaterial was synthesized by means of solution thermal plasma spray with water quenching of reacted species. Synthesis of the 8 mol% YSZ powder involved vaporization of a liquid precursor injected into a plasma jet where individual droplets, depending on their trajectory within the plasma, experienced varied thermal histories. Thus, not all the material produced underwent a complete gel → glass → nanocrystalline transformation sequence. Consequently, the collected powder contained a proportion of gel and glass (amorphous) state material. Additionally, the powder contained nano-scale and small micron-scale rapidly solidified 8 mol% YSZ particles. Following thermal treatment, the gel and the amorphous content transformed to produce (i) densely packed nanograin and (ii) chain-like nanograin aggregates. The nanograin aggregates are suggestive of a strong, yet short-range intergranular attraction, as predicted in computer simulation studies presented in the literature. Interestingly, this mixed morphology powder, after compaction and heat treatment at 1400 °C for 2 h, transformed into 98 % dense material with a homogeneous 200–500 nm grain size. For generating 8 mol% YSZ, the solution precursor plasma spray method offers a high synthesis rate using a low-cost precursor to produce powder that can be consolidated into morphologically homogeneous bulk nanomaterial.     

CRKL,AIFM3, AIF,BCL2, and UBASH3A during Human Kidney Development

We aimed to investigate the spatio-temporal expression of possible CAKUT candidate genes CRKL, AIFM3, and UBASH3A, as well as AIF and BCL2 during human kidney development. Human fetal kidney tissue was stained with antibodies and analyzed by fluorescence microscopy and RT-PCR. Quantification of positive cells was assessed by calculation of area percentage and counting cells in nephron structures. Results showed statistically significant differences in the temporal expression patterns of the examined markers, depending on the investigated developmental stage. Limited but strong expression of CRKL was seen in developing kidneys, with increasing expression up to the period where the majority of nephrons are formed. Results also lead us to conclude that AIFM3 and AIF are important for promoting cell survival, but only AIFM3 is considered a CAKUT candidate gene due to the lack of AIF in nephron developmental structures. Our findings imply great importance of AIFM3 in energy production in nephrogenesis and tubular maturation. UBASH3A raw scores showed greater immunoreactivity in developing structures than mature ones which would point to a meaningful role in nephrogenesis. The fact that mRNA and proteins of CRKL, UBASH3A, and AIFM3 were detected in all phases of kidney development implies their role as renal development control genes.     

The Expression of Connexin 37, 40, 43, 45 and Pannexin 1 in the Early Human Retina and Choroid Development and Tumorigenesis

The expression pattern of Connexins (Cx) 37, 40, 43, 45 and Pannexin 1 (Pnx1) was analyzed immunohistochemically, as well as semi-quantitatively and quantitatively in histological sections of developing 8th- to 12th-week human eyes and postnatal healthy eye, in retinoblastoma and different uveal melanomas. Expressions of both Cx37 and Cx43 increased during development but diminished in the postnatal period, being higher in the retina than in the choroid. Cx37 was highly expressed in the choroid of retinoblastoma, and Cx43 in epitheloid melanoma, while they were both increasingly expressed in mixoid melanoma. In contrast, mild retinal Cx40 expression during development increased to strong in postnatal period, while it was significantly higher in the choroid of mixoid melanoma. Cx45 showed significantly higher expression in the developing retina compared to other samples, while it became low postnatally and in all types of melanoma. Pnx1 was increasingly expressed in developing choroid but became lower in the postnatal eye. It was strongly expressed in epithelial and spindle melanoma, and particularly in retinoblastoma. Our results indicate importance of Cx37 and Cx40 expression in normal and pathological vascularization, and Cx43 expression in inflammatory response. Whereas Cx45 is involved in early stages of eye development, Pnx1might influence cell metabolism. Additionally, Cx43 might be a potential biomarker of tumor prognosis.     

Molecular Allergen-Specific IgE Recognition Profiles and Cumulative Specific IgE Levels Associated with Phenotypes of Cat Allergy

Cat allergy is a major trigger factor for respiratory reactions (asthma and rhinitis) in patients with immunoglobulin E (IgE) sensitization. In this study, we used a comprehensive panel of purified cat allergen molecules (rFel d 1, nFel d 2, rFel d 3, rFel d 4, rFel d 7, and rFel d 8) that were obtained by recombinant expression in Escherichia coli or by purification as natural proteins to study possible associations with different phenotypes of cat allergy (i.e., rhinitis, conjunctivitis, asthma, and dermatitis) by analyzing molecular IgE recognition profiles in a representative cohort of clinically well-characterized adult cat allergic subjects (n = 84). IgE levels specific to each of the allergen molecules and to natural cat allergen extract were quantified by ImmunoCAP measurements. Cumulative IgE levels specific to the cat allergen molecules correlated significantly with IgE levels specific to the cat allergen extract, indicating that the panel of allergen molecules resembled IgE epitopes of the natural allergen source. rFel d 1 represented the major cat allergen, which was recognized by 97.2% of cat allergic patients; however, rFel d 3, rFel d 4, and rFel d 7 each showed IgE reactivity in more than 50% of cat allergic patients, indicating the importance of additional allergens in cat allergy. Patients with cat-related skin symptoms showed a trend toward higher IgE levels and/or frequencies of sensitization to each of the tested allergen molecules compared with patients suffering only from rhinitis or asthma, while there were no such differences between patients with rhinitis and asthma. The IgE levels specific to allergen molecules, the IgE levels specific to cat allergen extract, and the IgE levels specific to rFel d 1 were significantly higher in patients with four different symptoms compared with patients with 1–2 symptoms. This difference was more pronounced for the sum of IgE levels specific to the allergen molecules and to cat extract than for IgE levels specific for rFel d 1 alone. Our study indicates that, in addition to rFel d 1, rFel d 3, rFel d 4, and rFel d 7 must be considered as important cat allergens. Furthermore, the cumulative sum of IgE levels specific to cat allergen molecules seems to be a biomarker for identifying patients with complex phenotypes of cat allergy. These findings are important for the diagnosis of IgE sensitization to cats and for the design of allergen-specific immunotherapies for the treatment and prevention of cat allergy.     

QbD for pediatric oral lyophilisates development: risk assessment followed by screening and optimization

Objective: This study proposed the development of oral lyophilisates with respect to pediatric medicine development guidelines, by applying risk management strategies and DoE as an integrated QbD approach.

Methods: Product critical quality attributes were overviewed by generating Ishikawa diagrams for risk assessment purposes, considering process, formulation and methodology related parameters. Failure Mode Effect Analysis was applied to highlight critical formulation and process parameters with an increased probability of occurrence and with a high impact on the product performance. To investigate the effect of qualitative and quantitative formulation variables D-optimal designs were used for screening and optimization purposes.

Results: Process parameters related to suspension preparation and lyophilization were classified as significant factors, and were controlled by implementing risk mitigation strategies. Both quantitative and qualitative formulation variables introduced in the experimental design influenced the product’s disintegration time, mechanical resistance and dissolution properties selected as CQAs. The optimum formulation selected through Design Space presented ultra-fast disintegration time (5?seconds), a good dissolution rate (above 90%) combined with a high mechanical resistance (above 600?g load).

Conclusions: Combining FMEA and DoE allowed the science based development of a product with respect to the defined quality target profile by providing better insights on the relevant parameters throughout development process. The utility of risk management tools in pharmaceutical development was demonstrated.     

Can Mean‐Curvature Flow be Modified to be Non‐singular?

This work considers the question of whether mean‐curvature flow can be modified to avoid the formation of singularities. We analyze the finite‐elements discretization and demonstrate why the original flow can result in numerical instability due to division by zero. We propose a variation on the flow that removes the numerical instability in the discretization and show that this modification results in a simpler expression for both the discretized and continuous formulations. We discuss the properties of the modified flow and present empirical evidence that not only does it define a stable surface evolution for genus‐zero surfaces, but that the evolution converges to a conformal parameterization of the surface onto the sphere.     

Connecting Polygonizations via Stretches and Twangs

We show that the space of polygonizations of a fixed planar point set S of n points is connected by O(n ²) “moves” between simple polygons. Each move is composed of a sequence of atomic moves called “stretches” and “twangs,” which walk between weakly simple “polygonal wraps” of S. These moves show promise to serve as a basis for generating random polygons.