Grand canonical Brownian dynamics simulations of adsorption and self-assembly of SAS-6 rings on a surface.

The Spindle Assembly Abnormal Protein 6 (SAS-6) forms dimers, which then self-assemble into rings that are critical for the nine-fold symmetry of the centriole organelle. It has recently been shown experimentally that the self-assembly of SAS-6 rings is strongly facilitated on a surface, shifting the reaction equilibrium by four orders of magnitude compared to the bulk. Moreover, a fraction of non-canonical symmetries (i.e., different from nine) was observed. In order to understand which aspects of the system are relevant to ensure efficient self-assembly and selection of the nine-fold symmetry, we have performed Brownian dynamics computer simulation with patchy particles and then compared our results with the experimental ones. Adsorption onto the surface was simulated by a grand canonical Monte Carlo procedure and random sequential adsorption kinetics. Furthermore, self-assembly was described by Langevin equations with hydrodynamic mobility matrices. We find that as long as the interaction energies are weak, the assembly kinetics can be described well by coagulation-fragmentation equations in the reaction-limited approximation. By contrast, larger interaction energies lead to kinetic trapping and diffusion-limited assembly. We find that the selection of nine-fold symmetry requires a small value for the angular interaction range. These predictions are confirmed by the experimentally observed reaction constant and angle fluctuations. Overall, our simulations suggest that the SAS-6 system works at the crossover between a relatively weak binding energy that avoids kinetic trapping and a small angular range that favors the nine-fold symmetry.

Genotypic variation of flavonols and antioxidant capacity in broccoli.

Flavonols are gaining increasing interests due to their diverse health benefits for humans. Broccoli is a main flavonol source in our diet, but the genetic variation of flavonols and their correlation with antioxidant capacity remain to be understood. Here, we examined variations of the two major flavonols kaempferol and quercetin in florets and leaves of 15 diverse broccoli accessions by ultra-performance liquid chromatography. Broccoli accumulated more kaempferol than quercetin in most of the accessions tested, with the ratios varying from 4.4 to 27.9 in leaves and 0.4 to 4.4 in florets. Total flavonoids showed 2.5-fold and 3.3-fold differences in leaves and florets of these accessions, respectively. Principle component analysis revealed that flavonols, along with the key biosynthetic pathway genes, correlated with antioxidant capacity related indicators. This study provides important information for broccoli flavonol genotypic variations and correlation with antioxidant capacity, and will facilitate the development of flavonol enriched cultivars in broccoli.

Quiste óseo aneurismático en el húmero distal. Reporte de un caso y tratamiento actual / Aneurysmal bone cyst in distal humerus. Case report and current treatment

El quiste óseo aneurismático es una lesión ósea benigna que se presenta a edad temprana; su comportamiento suele ser agresivo por lo cual, la resección quirúrgica y la prevención de su recidiva son los pilares fundamentales de el tratamiento. Presentamos el caso de una paciente de 6 años de edad residente en Gualaceo, Ecuador, con masa de crecimiento progresivo y deformante en el codo izquierdo. Por las características de los exámenes de imagen y el cuadro sintomático se dignostica quiste óseo aneurismático que fue tratado con cirugía de resección intralesional y terapia adyuvante (fresado de alta velocidad, coagulación térmica y crioterapia). Se confirmó el diagnostico mediante el estudio histopatológico posquirúrgico

The aneurysmal bone cyst is a benign osseous lesion of presentation at an early age whose behavior is usually aggressive, so its surgical resection and the prevention of its recurrence is the fundamental pillar for the treatment. We present the case of a girl of 6 years of age living in Gualaceo, Ecuador, with a mass of progressive and deforming growth in the left elbow. By characteristics in the imaging tests and clinical picture it was considered as an aneurysmal bone cyst which was treated with intralesional resection surgery and adjuvant therapy (high speed burr, thermal coagulation and cryotherapy). The diagnosis was confirmed with postoperative histopathological study

Effect of subinihibitory and inhibitory concentrations of Plectranthus amboinicus (Lour.) Spreng essential oil on Klebsiella pneumoniae.

We evaluated the antimicrobial activity and some mechanisms used by subinhibitory and inhibitory concentrations of the essential oil, obtained from leaves of Plectranthus amboinicus, against a standard strain of Klebsiella pneumoniae and 5 multiresistant clinical isolates of the bacteria. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), the rate of kill and the pH sensitivity of the essential oil were determined by microdilution tests performed in 96-well plates. Subinhibitory and inhibitory concentrations of the essential oil were tested in order to check its action on K. pneumoniae membrane permeability, capsule expression, urease activity and cell morphology. The MIC and MBC of the essential oil were 0.09±0.01%. A complete inhibition of the bacterial growth was observed after 2 h of incubation with twice the MIC of the essential oil. A better MIC was found when neutral or alkaline pH broth was used. Alteration in membrane permeability was found by the increase of crystal violet uptake when the bacteria were incubated with twice the MIC levels of the essential oil. The urease activity could be prevented when all the subinhibitory concentrations were tested in comparison to the untreated group (p<0.001). Alteration of the bacterial morphology besides inhibition of the capsule expression was verified by atomic force microscopy, and Anthony's stain method, respectively. Our data allow us to conclude that the essential oil of P. amboinicus can be a good candidate for future research.

Risk-factors for non-adherence to antiretroviral therapy.

Cross-sectional study analyzed as case-control to identify risk factors for non-adherence to antiretroviral therapy. We studied 412 out-clinics HIV infected subjects of three public hospitals of Recife, Pernambuco. The objective was to examine the association between non-adherence to the antiretroviral therapy and biological, social-behavior and demographics and economic factors, factors related to the disease and/or treatment, factors related to life habits and depression symptoms. Variables significantly associated with non-adherence to antiretroviral therapy were: time elapsed since HIV diagnosis (p = 0.002), daily dose (p = 0.046), use of alcohol (p = 0.030) and past drug use (p = 0.048), and borderline p-values were found for educational level (p = 0.093) and family monthly income (p = 0.08). In the multivariable analysis, the factors that remained in the final model were family monthly income, time period with HIV infection and use of alcohol. No association was observed between non-adherence to antiretroviral therapy and gender, age, sexual orientation, marital status, educational level and place of residence. Based on our results and the local situation we suggest: assessment of social needs; training of partners and/or families on supporting adherence, creation of 'adherence groups' to motivate and to reassure patients on the benefits of treatment; counseling and/or psychotherapy for alcohol drinkers.

Risk-factors for non-adherence to antiretroviral therapy / Fatores preditivos de não-adesão à terapia antiretroviral

Cross-sectional study analyzed as case-control to identify risk factors for non-adherence to antiretroviral therapy. We studied 412 out-clinics HIV infected subjects of three public hospitals of Recife, Pernambuco. The objective was to examine the association between non-adherence to the antiretroviral therapy and biological, social-behavior and demographics and economic factors, factors related to the disease and/or treatment, factors related to life habits and depression symptoms. Variables significantly associated with non-adherence to antiretroviral therapy were: time elapsed since HIV diagnosis (p = 0.002), daily dose (p = 0.046), use of alcohol (p = 0.030) and past drug use (p = 0.048), and borderline p-values were found for educational level (p = 0.093) and family monthly income (p = 0.08). In the multivariable analysis, the factors that remained in the final model were family monthly income, time period with HIV infection and use of alcohol. No association was observed between non-adherence to antiretroviral therapy and gender, age, sexual orientation, marital status, educational level and place of residence. Based on our results and the local situation we suggest: assessment of social needs; training of partners and/or families on supporting adherence, creation of "adherence groups" to motivate and to reassure patients on the benefits of treatment; counseling and/or psychotherapy for alcohol drinkers.

Estudo transversal com análise tipo caso-controle, que avaliou 412 pacientes de hospitais públicos do Recife - PE, com o objetivo de identificar fatores preditivos de não adesão à terapia antiretroviral. Verificou-se associação entre não adesão à terapia antiretroviral e aspectos biológicos, sócio-comportamentais e demográficos, econômicos, relacionados à doença e ao tratamento, aos hábitos de vida e aos distúrbios do humor. Variáveis com associação estatisticamente significante com não adesão na análise univariada foram: tempo de diagnóstico (p = 0,002), maior número diário de comprimidos (p = 0,046), uso de álcool (p = 0,030) e uso de drogas no passado (p = 0,048). Observou-se associação limítrofe com grau de instrução (p = 0,093) e renda mensal familiar (p = 0,08). Após análise multivariada, permaneceram no modelo final: renda mensal familiar, tempo de diagnóstico e uso de álcool. Não houve associação entre gênero, idade, comportamento sexual, estado civil, grau de instrução, município de residência e não adesão à terapia antiretroviral. Baseados nos nossos resultados e nas características da população estudada sugerimos: valorização das necessidades sociais, sensibilização de parceiros e/ou familiares para estimular a adesão, criação de grupos de adesão para motivar e persuadir os pacientes sobre os benefícios do tratamento, aconselhamento e/ou psicoterapia para alcoolistas.

The role of magnetic resonance imaging in the postoperative management of cholesteatomas.

UNLABELLED: Conventional CT and MRI scans have low specificity when it comes to differentiating granulation tissue from relapsing cholesteatoma. AIM: this paper aims to analyze the use of DWI and delayed post-contrast T1-weighed imaging in the detection of recurring cholesteatomas. MATERIALS AND METHOD: this is a cross-sectional prospective study that looked at 17 cholesteatoma patients postoperatively. All patients underwent diffusion magnetic resonance imaging at 1.5T, T1, T2, and delayed post-contrast T1 and images were produced from both coronal and axial planes. Two radiologists assessed the images and decided consensually that the presence of hyperintensive signal in DWI on T2, iso/hypointensive signal on T1, and absence of contrast uptake were indicative of relapsing cholesteatoma. Surgical review findings were compared to DWI scans. RESULTS: eleven of the twelve cases of recurring cholesteatoma presented hyperintensive signal in the DWI scans. None of the patients with granulation tissue in the surgical wound presented hyperintensive signal in the DWI scans. A patient with an abscess in the internal acoustic meatus also presented a hyperintensive signal in the DWI scans. Sensibility, specificity, positive predictive value and negative predictive value were 91.6%, 60.0%, 84.6%, and 75.0%, respectively. CONCLUSION: DWI combined with delayed post-contrast T1 SE sequence proved to be useful in the differential diagnosis of granulation tissue and recurring cholesteatoma.

Aplicação da ressonância magnética no acompanhamento da cirurgia do colesteatoma / The role of magnetic resonance imaging in the postoperative management of cholesteatomas

A tomografia computadorizada e ressonância magnética (RM) com seqüências convencionais têm baixa especificidade para a diferenciação entre tecido de granulação e recidiva de colesteatoma. OBJETIVO: Avaliar a aplicação da RM com sequência de difusão e pós-contraste T1 tardio na detecção de recidiva de colesteatoma. MATERIAL E MÉTODO: Realizado estudo transversal prospectivo de dezessete pacientes estudados no pós-operatório de colesteatoma utilizando RM de 1.5 T com seqüência difusão, T1, T2 e pós-contraste T1 tardio nos planos coronal e axial. Dois radiologistas avaliaram e decidiram em consenso a presença de foco de hipersinal na difusão e T2, iso/hipossinal em T1 e ausência de impregnação pelo contraste como suspeitos de recidiva de colesteatoma. Os achados da revisão cirúrgica foram comparados com o resultado da RM. RESULTADOS: Onze dos doze casos de recidiva de colesteatoma apresentaram hipersinal na difusão. Todos os pacientes com tecido de granulação na cavidade cirúrgica não apresentaram alteração de sinal na difusão. Um paciente com abscesso no conduto auditivo interno também apresentou hipersinal na difusão. A sensibilidade, especificidade, valor preditivo positivo e negativo foram respectivamente 91,6 por cento, 60 por cento, 84,6 por cento e 75 por cento. CONCLUSÃO: A seqüência de difusão combinada com pós-contraste tardio pode ser útil na diferenciação entre tecido de granulação e recidiva de colesteatoma.

Conventional CT and MRI scans have low specificity when it comes to differentiating granulation tissue from relapsing cholesteatoma. AIM: this paper aims to analyze the use of DWI and delayed post-contrast T1-weighed imaging in the detection of recurring cholesteatomas. MATERIALS AND METHOD: this is a cross-sectional prospective study that looked at 17 cholesteatoma patients postoperatively. All patients underwent diffusion magnetic resonance imaging at 1.5T, T1, T2, and delayed post-contrast T1 and images were produced from both coronal and axial planes. Two radiologists assessed the images and decided consensually that the presence of hyperintensive signal in DWI on T2, iso/hypointensive signal on T1, and absence of contrast uptake were indicative of relapsing cholesteatoma. Surgical review findings were compared to DWI scans. RESULTS: eleven of the twelve cases of recurring cholesteatoma presented hyperintensive signal in the DWI scans. None of the patients with granulation tissue in the surgical wound presented hyperintensive signal in the DWI scans. A patient with an abscess in the internal acoustic meatus also presented a hyperintensive signal in the DWI scans. Sensibility, specificity, positive predictive value and negative predictive value were 91.6 percent, 60.0 percent, 84.6 percent, and 75.0 percent, respectively. CONCLUSION: DWI combined with delayed post-contrast T1 SE sequence proved to be useful in the differential diagnosis of granulation tissue and recurring cholesteatoma.

CAMBIOS EN LA ESTRUCTURA DE LA POBLACIÓN DE Boeckella gracilis (CRUSTACEA, CENTROPAGIDAE) EN EL PLANCTON DEL LAGO DE TOTA, BOYACÁ - COLOMBIA / Changes Of The Population Structure Of Boeckella gracilis (Crustacea, Centropagidae) In The Plankton From Lago de Tota, Boyaca - Colombia

Se realizó un seguimiento a la población de Boeckella gracilis Daday, 1902 en el lago de Tota, Boyacá, Colombia , durante seis meses con periodicidad quincenal a partir de mayo de 2004. La densidad poblacional fue de 11.968 Ind.m-3 en promedio y expresó un incremento progresivo hasta el final del estudio que corresponde a época de fuertes lluvias en la zona y aguas altas en el lago. Los machos adultos dominaron en densidad y biomasa, constituyendo el 32,5% y el 35,8% de la población, respectivamente. La fecundidad promedio se estimó en 0,32 huevos por hembra. En la época de aguas altas se presentó un aumento de la actividad reproductiva evidenciado por el incremento de la fecundidad y el mayor número de copepoditos. Con base en el análisis de componentes principales, la transparencia, el pH y el oxígeno disuelto fueron las variables determinantes de la expresión temporal del hábitat. El comportamiento de la biomasa de la población se asoció positivamente con la variación de la densidad de los adultos y copepoditos y negativamente con la concentración de oxígeno disuelto en el lago.

The population of Boeckella gracilis Daday, 1902 of the lago de Tota, Boyacá, Colombia , was studied during a period of six months forthnightly starting in May 2004. The population density with a mean of 11.968 nd.m-3 showed a progressive increase to the end of the period of study corresponding to high values of rain intensity in the region and high water level of the lake. Mature males dominated in density and biomass, achieving 32.5% and 35.8% respectively. Fecundity indicated a mean of 0.32 eggs for female. In the period of high water level an increase of the reproductive activity occured and was evidenced by the increment on fecundity and the highest copepodite density. The analysis of main components showed that transparency, pH and dissolved oxygen were the decisive variables for the temporal expression of the habitat. Biomass variation was positively associated to adult and copepodit density variation and negatively related to oxygen dissolved concentration in the lake.