Quercetin in lyotropic liquid crystalline formulations: Physical, chemical and functional stability

The purpose of this study was to develop a lyotropic liquid crystalline formulation using the emulsifier vitamin E TPGS and evaluate its behavior after incorporation of a flavonoid, quercetin. The physical (macro and microscopic), chemical (determination of quercetin content by the HPLC method) and functional (determination of quercetin antioxidant activity by DPPH center dot assay) stability of the lamellar liquid crystalline formulation containing flavonoid was evaluated when stored at 4+/-2 degrees C; 30+/-2 degrees C/70+/-5% RH (relative humidity) and 40+/-2 degrees C/70+/-5% RH during 12 months. The lamellar liquid crystalline structure of the formulation was maintained during the experiment, however chemical and functional stability results showed a great influence of the storage period in all conditions tested. A significant decrease in quercetin content (approximately 40%) was detected during the first month of storage and a similar significant loss in antioxidant activity was detected after 6 months. The remaining flavonoid content was unchanged during the final 6 months of the experimental period. The results suggest possible interactions between quercetin and the liquid crystalline formulation, which could inhibit or reduce the quercetin activity incorporated in the system. In conclusion, the present study demonstrated that incorporation of quercetin (1%) did not affect the liquid crystalline structure composed of vitamin E TPGS/IPM/PG-H2O (1:1) at 63.75/21.25/15 (w/w/w). Nevertheless, of the total quercetin incorporated in the system only 60% was free to act as an antioxidant.

The relationship between knee strength and functional stability before and after anterior cruciate ligament reconstruction

Functional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre- and post-operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons. Isokinetic strength assessment of quadriceps and hamstring muscles was performed at a rate of movement of 60% and 120degrees/s. Functional stability was determined by performance during five functional stability tests that included the shuttle run, side step, carioca, single and triple hop tests. Pearson's correlation coefficient statistics were applied to pre-operative and post-operative data respectively. These analyses demonstrated a significant positive correlation between quadriceps strength indices at both testing speeds and the two hop tests pre-operatively (p's < 0.007) and between quadriceps strength indices at both speeds and all five functional tests post-operatively (p's < 0.01). Assessed using Steiger's formula, there was a significant increase in the correlation between quadriceps strength indices and three functional tests post-operatively compared to pre-operatively (p < 0.05). No significant correlation between hamstring strength indices and functional scores existed pre- or post-operatively. This study has shown a significant correlation exists between quadriceps strength indices and functional stability both before and after surgery, this relationship does not reach significance between hamstring strength indices and functional stability. (C) 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Characterization and stability study of a water-in-oil microemulsion incorporating quercetin

Background: The effectiveness of a water/oil (w/o) microemulsion containing quercetin against ultraviolet B radiation (UVB) induced damage was recently demonstrated by our group. However, during the development of new pharmaceutical products, the evaluation of percutaneous absorption and in vivo effectiveness should be accompanied by evaluation of stability parameters as an integral part of the process. Objective: The aim was to investigate the stability of the final microemulsion formulation considering the temperature ranges of storage and application. Methods: The physical, chemical, and functional stability of this formulation under different conditions of storage during 12 months and the photostability of quercetin incorporated into this system over UVB exposure for 7 days were evaluated. Results: Although the results indicated a notable physical stability of the w/o microemulsions during the experimental period under all employed conditions, in both, the chemical and functional studies, a significant loss of quercetin content and antioxidant activity was found after 6 months of storage at 30 degrees C/70% relative humidity and after 2 months at 40 degrees C/70% relative humidity. The photostability study results demonstrated that the incorporation of quercetin into the w/o microemulsion maintained the previously demonstrated photostability of this flavonoid under forced exposure to UVB irradiation. Conclusion: Thus, this work demonstrates that special storage conditions (at 4 +/- 2 degrees C) are necessary to maintain the functionality of the w/o microemulsion containing quercetin and mainly emphasizes the importance of studying physical, chemical, and functional parameters at the same time during stability evaluation of active principles.

Taxonomical vs. functional responses of bee communities to fire in two contrasting climatic regions

Valuable insights into mechanisms of community responses to environmental change can be gained by analysing in tandem the variation in functional and taxonomic composition along environmental gradients. We assess the changes in species and functional trait composition (i.e. dominant traits and functional diversity) of diverse bee communities in contrasting fire-driven systems in two climatic regions: Mediterranean (scrub habitats in Israel) and temperate (chestnut forests in southern Switzerland). In both climatic regions, there were shifts in species diversity and composition related to post-fire age. In the temperate region, functional composition responded markedly to fire; however, in the Mediterranean, the taxonomic response to fire was not matched by functional replacement. These results suggest that greater functional stability to fire in the Mediterranean is achieved by replacement of functionally similar species (i.e. functional redundancy) which dominate under different environmental conditions in the heterogeneous landscapes of the region. In contrast, the greater functional response in the temperate region was attributed to a more rapid post-fire vegetation recovery and shorter time-window when favourable habitat was available relative to the Mediterranean. Bee traits can be used to predict the functional responses of bee communities to environmental changes in habitats of conservation importance in different regions with distinct disturbance regimes. However, predictions cannot be generalized from one climatic region to another where distinct habitat configurations occur.

Structural and functional analysis of centromeric chromatin

Animal neocentromeres are defined as ectopic centromeres that have formed in non-centromeric locations and avoid some of the features, like the DNA satellite sequence, that normally characterize canonical centromeres. Despite this, they are stable functional centromeres inherited through generations. The only existence of neocentromeres provide convincing evidence that centromere specification is determined by epigenetic rather than sequence-specific mechanisms. For all this reasons, we used them as simplified models to investigate the molecular mechanisms that underlay the formation and the maintenance of functional centromeres. We collected human cell lines carrying neocentromeres in different positions. To investigate the region involved in the process at the DNA sequence level we applied a recent technology that integrates Chromatin Immuno-Precipitation and DNA microarrays (ChIP-on-chip) using rabbit polyclonal antibodies directed against CENP-A or CENP-C human centromeric proteins. These DNA binding-proteins are required for kinetochore function and are exclusively targeted to functional centromeres. Thus, the immunoprecipitation of DNA bound by these proteins allows the isolation of centromeric sequences, including those of the neocentromeres. Neocentromeres arise even in protein-coding genes region. We further analyzed if the increased scaffold attachment sites and the corresponding tighter chromatin of the region involved in the neocentromerization process still were permissive or not to transcription of within encoded genes. Centromere repositioning is a phenomenon in which a neocentromere arisen without altering the gene order, followed by the inactivation of the canonical centromere, becomes fixed in population. It is a process of chromosome rearrangement fundamental in evolution, at the bases of speciation. The repeat-free region where the neocentromere initially forms, progressively acquires extended arrays of satellite tandem repeats that may contribute to its functional stability. In this view our attention focalized to the repositioned horse ECA11 centromere. ChIP-on-chip analysis was used to define the region involved and SNPs studies, mapping within the region involved into neocentromerization, were carried on. We have been able to describe the structural polymorphism of the chromosome 11 centromeric domain of Caballus population. That polymorphism was seen even between homologues chromosome of the same cells. That discovery was the first described ever. Genomic plasticity had a fundamental role in evolution. Centromeres are not static packaged region of genomes. The key question that fascinates biologists is to understand how that centromere plasticity could be combined to the stability and maintenance of centromeric function. Starting from the epigenetic point of view that underlies centromere formation, we decided to analyze the RNA content of centromeric chromatin. RNA, as well as secondary chemically modifications that involve both histones and DNA, represents a good candidate to guide somehow the centromere formation and maintenance. Many observations suggest that transcription of centromeric DNA or of other non-coding RNAs could affect centromere formation. To date has been no thorough investigation addressing the identity of the chromatin-associated RNAs (CARs) on a global scale. This prompted us to develop techniques to identify CARs in a genome-wide approach using high-throughput genomic platforms. The future goal of this study will be to focalize the attention on what strictly happens specifically inside centromere chromatin.

The thermodynamic origin of the stability of a thermophilic ribozyme

Understanding the mechanism of thermodynamic stability of an RNA structure has significant implications for the function and design of RNA. We investigated the equilibrium folding of a thermophilic ribozyme and its mesophilic homologue by using hydroxyl radical protection, small-angle x-ray scattering, and circular dichroism. Both RNAs require Mg2+ to fold to their native structures that are very similar. The stability is measured as a function of Mg2+ and urea concentrations at different temperatures. The enhanced stability of the thermophilic ribozyme primarily is derived from a tremendous increase in the amount of structure formed in the ultimate folding transition. This increase in structure formation and cooperativity arises because the penultimate and the ultimate folding transitions in the mesophilic ribozyme become linked into a single transition in the folding of the thermophilic ribozyme. Therefore, the starting point, or reference state, for the transition to the native, functional thermophilic ribozyme is significantly less structured. The shift in the reference state, and the resulting increase in folding cooperativity, is likely due to the stabilization of selected native interactions that only form in the ultimate transition. This mechanism of using a less structured intermediate and increased cooperativity to achieve higher functional stability for tertiary RNAs is fundamentally different from that commonly proposed to explain the increased stability of thermophilic proteins.

Exhaled nitric oxide for monitoring childhood asthma inflammation compared to sputum analysis, serum interleukins and pulmonary function

The level of fractional exhaled nitric oxide (FENO) is significantly elevated in uncontrolled asthma and decreases after anti-inflammatory therapy The aim of this prospective study was to analyze the behavior of FENO in the follow-up and management of the inflammation in asthmatic pediatric patients treated with inhaled corticosteroids (ICS), compared to sputum cellularity, serum interleukins (IL), and pulmonary function. Twenty-six clinically stable asthmatic children aged from 6 to 18 years, previously treated or not with ICS were included. Following an international consensus (GINA), the patients were submitted to standard treatment with inhaled fluticasone for 3 months according to the severity of the disease. During this period, each patient underwent three assessments at intervals of approximately 6 weeks: Each evaluation consisted of the measurement of FENO, determination of serum interleukins IL-5, IL-10, IL-13, and interferon gamma (INF-gamma), spirometry and cytological analysis of spontaneous or induced sputum. A significant reduction in mean FENO and IL-5, without concomitant changes in FEV1, was observed along the study. There was no significant correlation between FeNO and FEV1 in the three assessments. A significant correlation between FeNO and IL-5 levels was only observed in the third assessment (r = 0.499, P=0.025). In most patients, serum IL-10, IL-13, and INF-gamma concentrations were undetectable throughout the study Sputum samples were obtained spontaneously in 11 occasions and in 56 by induction with 3% hypertonic saline solution (success rate: 50.8%), with 39 (69.9%) of them adequate for analysis. Only two of the 26 patients produced adequate samples in the three consecutive evaluations, which impaired the determination of a potential association between sputum cellularity and FeNO levels throughout the study. In conclusion, among the parameters of this study, it was difficult to perform and to interpret the serial analysis of spontaneous or induced sputum. Serum interleukins, which remained at very low or undetectable levels in most patients, were not found to be useful for therapeutic monitoring, except for IL-5 that seems to present some correlation with levels of FeNO exhaled. Monitoring of the mean FEV1 indicated no significant variations during the treatment, demonstrating that functional stability or the absence of obstruction may not reflect the adequate management of asthma. Serial measurement of FeNO seemed to best reflect the progressive anti-inflammatory action of ICS in asthma.

Tibial plato leveling osteotomy

The tibial plateau leveling osteotomy (TPLO) is a relatively new and innovative surgical treatment for the cranial cruciate ligament rupture in the canine species. The real intent of the procedure is to provide functional stability to the stifle joint by eliminating or neutralizing the cranial tibial thrust during weight bearing instead to restore the cranial cruciate ligament function. The proposal of this study is to report a review of the TPLO procedure, emphasizing procedure, surgical technique, post operative care and complications. The TPLO procedure consists in a radial osteotomy in the tibial plato and rotation of the caudal plateau in order to obtain a desired angle, After the leveling of the tibial plateau, a bone plate and screws are used to stabilize the osteotomy until bone is healed up. The complications that have been associated with the procedure include tibial tuberosity fracture and patellar tendon tendinosis. This procedure has become increasingly more popular for surgical treatment of cranial cruciate ligament injuries in large breed dog. The long term clinical results have not been completely elucidated yet. It has been showed that this technique doesn`t halt the degenerative joint disease.

Characterization of an antioxidant surfactant-free topical formulation containing Castanea sativa leaf extract

Context: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer. Objective: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation. Materials and methods: Physical, microbiological and functional stability were evaluated during 6 months storage at 20 °C and 40 °C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed. Results and discussion: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20 °C for 6 months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610 ± 70 µgh−0.5) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4 h after product’s application. Conclusion: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.

The role of fungi and bacteria on the organic matter decomposition process in streams: interaction and relevance in biofilms

L'objectiu d'aquest estudi és el d'investigar sobre l'ús de matèria orgànica per part dels fongs i bacteris que colonitzen diferents substrats bentònics en rius Mediterranis i analitzar l'efecte dels factors ambientals i antròpics sobre l'estabilitat estructural i funcional de les comunitats del biofilm. La metodologia emprada en aquest estudi consisteix en: i) anàlisi de la biomassa bacteriana i fúngica, ii) anàlisi de la composició de les comunitats bentòniques (identificació d'hifomicets aquàtics i anàlisi del 16S rDNA bacterià), i iii) anàlisi de l'activitat enzimàtica extracel·lular relacionada amb el reciclatge de matèria orgànica en rius.

Influência de substâncias bioativas na estabilidade fisico-química e funcional de emulsões fotoprotetoras

Autilização de filtros ultravioletas isolados em formulações fotoprotetoras, origina produtos com proteção limitada contra as radiações solares, o que evidencia a necessidade de associar compostos bioativos. Estudos anteriores demonstraram que a rutina, um composto bioativo, interage sinergicamente com filtros solares incorporados em preparações fotoprotetoras. Portanto, este trabalho teve como objetivo avaliar a influência da rutina sobre a estabilidade físico-química e funcional de emulsões fotoprotetoras. 16 formulações foram desenvolvidas, submetidas ao teste de estabilidade preliminar e caracterizadas de acordo com o pH, perfil reológico e eficácia fotoprotetora in vitro . A formulação com o melhor desempenho e a formulação correspondente, sem rutina, foram submetidos ao teste de estabilidade normal. Todas as formulações apresentaram valores de pH compatível com a pele e comportamento reológico semelhante. A formulação F16 e a mesma formulação, sem rutina, foram submetidas ao teste de estabilidade normal e apresentaram valores de pH semelhantes e perfis reológicos que foram mantidos ao longo dos dias de análise. Aatividade antirradicalar foi estável apenas para formulações armazenadas a 5,0 ± 0,5°C. A eficácia fotoprotetora demonstrou resultados semelhantes entre ambas as formulações, que também foi observado em todos os dias de análise. Em conclusão, rutina não influenciou a fotoestabilidade da formulação sob as condições adotadas.

Towards pain-free diagnosis of skin diseases through multiplexed microneedles: biomarker extraction and detection using a highly sensitive blotting method

Immunodiagnostic microneedles provide a novel way to extract protein biomarkers from the skin in a minimally invasive manner for analysis in vitro. The technology could overcome challenges in biomarker analysis specifically in solid tissue, which currently often involves invasive biopsies. This study describes the development of a multiplex immunodiagnostic device incorporating mechanisms to detect multiple antigens simultaneously, as well as internal assay controls for result validation. A novel detection method is also proposed. It enables signal detection specifically at microneedle tips and therefore may aid the construction of depth profiles of skin biomarkers. The detection method can be coupled with computerised densitometry for signal quantitation. The antigen specificity, sensitivity and functional stability of the device were assessed against a number of model biomarkers. Detection and analysis of endogenous antigens (interleukins 1α and 6) from the skin using the device was demonstrated. The results were verified using conventional enzyme-linked immunosorbent assays. The detection limit of the microneedle device, at ≤10 pg/mL, was at least comparable to conventional plate-based solid-phase enzyme immunoassays.

O contrato psicológico e o comprometimento organizacional de servidores públicos de agências reguladoras brasileiras

Este estudo versa sobre contrato psicológico e comprometimento organizacional, no contexto das agências reguladoras, autarquias da administração pública brasileira. Os contratos psicológicos são as expectativas e crenças dos indivíduos a respeito das obrigações recíprocas entre eles e suas organizações. O contrato psicológico é criado de forma espontânea e não faz parte do acordo formal entre empregado e empregador. O comprometimento organizacional refere-se à forma como cada pessoa percebe a motivação de seu vínculo com a organização, que pode ser de cunho afetivo, que reflete um desejo, instrumental, que reflete uma necessidade ou normativo, que reflete uma obrigação. A pesquisa realizada objetivou identificar se existe alguma relação e qual seria esta relação, entre os quatros tipos de contrato psicológico: relacional, equilibrado, transacional e transitório, com os três tipos de comprometimento organizacional, dos servidores públicos de agências reguladoras, que têm direito à estabilidade funcional, o que significa direito de manter o emprego permanentemente. O resultado da pesquisa demonstrou as relações existentes entre as variações de contrato psicológico e comprometimento organizacional dos servidores, apontando para a predominância do contrato transitório e do comprometimento instrumental.

Conservative condylectomy for management of osteochondroma of the mandibular condyle

Osteochondroma is one of the most common benign tumors of the skeleton. This tumor is rare in the craniofacial region, with the most common sites of occurrence being the coronoid process of the mandible and the mandibular condyle. Traditionally, the treatments of these lesions include total condylectomy or local resection of the lesion. Conservative condylectomy procedure with reshaping of the remaining condylar neck and repositioning of the articular disk has been suggested. This article aimed to describe a 35-year-old woman with osteochondroma in the left mandibular condyle who was treated by conservative condylectomy. The patient has been free of recurrence for 2 years, showing good aesthetic and functional stability. Copyright © 2013 by Mutaz B. Habal, MD.