The major Thiobacillus ferrooxidans outer membrane protein forms low conductance ion channels in planar lipid bilayers

AbstractA protein isolated and purified from the outer membrane of the acidophilic, chemolithotrophic bacterium, Thiobacillus ferrooxidans with an oligomeric molecular weight of 90 000 Da (p9O) was incorporated into phosphatidylethanolamine planar lipid bilayers. The protein formed slightly anionic channels in KCl solutions, with a conductance of 25 pS in 100 mM KCl. The current—voltage relationship was linear between ±6O mV, and the conductance was a saturating function of the salt concentration. These channels fluctuated from a single open to closed state at low potentials, but present flickering activity at higher potentials

Longitudinal pathways of cerebrospinal fluid and positron emission tomography biomarkers of amyloid-β positivity.

peer reviewedMismatch between CSF and PET amyloid-β biomarkers occurs in up to ≈20% of preclinical/prodromal Alzheimer's disease individuals. Factors underlying mismatching results remain unclear. In this study we hypothesized that CSF/PET discordance provides unique biological/clinical information. To test this hypothesis, we investigated non-demented and demented participants with CSF amyloid-β(42) and [18F]Florbetapir PET assessments at baseline (n = 867) and at 2-year follow-up (n = 289). Longitudinal trajectories of amyloid-β positivity were tracked simultaneously for CSF and PET biomarkers. In the longitudinal cohort (n = 289), we found that participants with normal CSF/PET amyloid-β biomarkers progressed more frequently toward CSF/PET discordance than to full CSF/PET positivity (χ(2)((1)) = 5.40; p < 0.05). Progression to CSF+/PET+ status was ten times more frequent in cases with discordant biomarkers, as compared to csf-/pet- cases (χ(2)((1)) = 18.86; p < 0.001). Compared to the CSF+/pet- group, the csf-/PET+ group had lower APOE-ε4ε4 prevalence (χ(2)((6)) = 197; p < 0.001; n = 867) and slower rate of brain amyloid-β accumulation (F((3,600)) = 12.76; p < 0.001; n = 608). These results demonstrate that biomarker discordance is a typical stage in the natural history of amyloid-β accumulation, with CSF or PET becoming abnormal first and not concurrently. Therefore, biomarker discordance allows for identification of individuals with elevated risk of progression toward fully abnormal amyloid-β biomarkers, with subsequent risk of neurodegeneration and cognitive decline. Our results also suggest that there are two alternative pathways ("CSF-first" vs. "PET-first") toward established amyloid-β pathology, characterized by different genetic profiles and rates of amyloid-β accumulation. In conclusion, CSF and PET amyloid-β biomarkers provide distinct information, with potential implications for their use as biomarkers in clinical trials

Psychosocial correlates of eating behavior in children and adolescents: a review

<p>Abstract</p> <p>Background</p> <p>Understanding the correlates of dietary intake is necessary in order to effectively promote healthy dietary behavior among children and adolescents. A literature review was conducted on the correlates of the following categories of dietary intake in children and adolescents: Fruit, Juice and Vegetable Consumption, Fat in Diet, Total Energy Intake, Sugar Snacking, Sweetened Beverage Consumption, Dietary Fiber, Other Healthy Dietary Consumption, and Other Less Healthy Dietary Consumption in children and adolescents.</p> <p>Methods</p> <p>Cross-sectional and prospective studies were identified from PubMed, PsycINFO and PsycArticles by using a combination of search terms. Quantitative research examining determinants of dietary intake among children and adolescents aged 3–18 years were included. The selection and review process yielded information on country, study design, population, instrument used for measuring intake, and quality of research study.</p> <p>Results</p> <p>Seventy-seven articles were included. Many potential correlates have been studied among children and adolescents. However, for many hypothesized correlates substantial evidence is lacking due to a dearth of research. The correlates best supported by the literature are: perceived modeling, dietary intentions, norms, liking and preferences. Perceived modeling and dietary intentions have the most consistent and positive associations with eating behavior. Norms, liking, and preferences were also consistently and positively related to eating behavior in children and adolescents. Availability, knowledge, outcome expectations, self-efficacy and social support did not show consistent relationships across dietary outcomes.</p> <p>Conclusion</p> <p>This review examined the correlates of various dietary intake; Fruit, Juice and Vegetable Consumption, Fat in Diet, Total Energy Intake, Sugar Snacking, Sweetened Beverage Consumption, Dietary Fiber, Other Healthy Dietary Consumption, and Other Less Healthy Dietary Consumption in cross-sectional and prospective studies for children and adolescents. The correlates most consistently supported by evidence were perceived modeling, dietary intentions, norms, liking and preferences. More prospective studies on the psychosocial determinants of eating behavior using broader theoretical perspectives should be examined in future research.</p

Risk factors for incident dementia among older Cubans

Introduction: Little is known about risk factors of dementia in Latin American countries. We aimed to identify socio-demographic, health and lifestyle risk factors of incident dementia in Cuban older adults. Methods: Data were from 1,846 participants in the Cuban cohort of the 10/66 Dementia Research Group. Participants completed questionnaires, health examinations, and cognitive tests at baseline (2003-2006) and 4.5 years later (2007-2010). Associations between risk factors (baseline) and incident dementia (follow-up) were examined using logistic regression. Results: Just over 9% of participants developed dementia. Overall, older age and low physical activity were associated with incident dementia. In those 65-74 years of age, depression, stroke and low physical activity were associated with incident dementia. In those ≥75 years of age, low physical activity, never eating fish, and smoking were associated with incident dementia. Conclusions: Modifiable lifestyle factors play an important role in developing dementia in Cuban older adults. This knowledge opens up opportunities for preventive strategies

Mesenchymal stem cells protect sensory neurons, but not cortical neurons, from the chemotherapeutics-induced neurotoxicity

Mesenchymal stem cells (MSCs) have been often proposed for the therapy of several neurological diseases, due to their manifold peculiar properties. In particular, since it has been previously demonstrated that these cells are able to increase the survival of untreated sensory neurons [1], in this work we evaluated their possible protective effect on sensory neurons previously exposed to toxic agents. This could be particularly relevant to design a supportive therapy to counteract the peripheral neuropathy, a very common side effect of several chemotherapeutic agents, such as platinum and taxanes compounds, which often represents their dose limiting factor [2]. Several strategies have been suggested to reduce drug neurotoxicity without affecting the antineoplastic potential, but up to now results were not encouraging [3]. Here we demonstrated that Cisplatin (CDDP) and Paclitaxel-treated sensory neurons are protected by the co-culture with MSCs, but in two different manners: through a direct contact able to block apoptosis for CDDP-treated neurons, and by the release of trophic factors (including glutathione) for Paclitaxel-treated ones. In addition, the MSCs’ effectiveness was also verified on cortical neurons, since the recent advances in targeted drug delivery allowed to drive chemotherapeutic drugs also to the central nervous system. We verified that cortical neurons are more vulnerable to the toxic action of the drugs, and overall that MSCs fail at all to protect them. All these data demonstrated that MSCs are potentially useful to limit the peripheral neuropathy onset for their protective effect on injured-sensory neurons, but they also identified for the first time a different susceptibility of cortical and sensory neurons to MSC action

Detection, quantification and genetic variability of Mycoplasma hyopneumoniae from apparently healthy and pneumonic swine

Mycoplasma hyopneumoniae is the causative agent of the Porcine Enzootic Pneumonia. However, this mycoplasma can be detected in healthy and symptomatic pigs, that difficults the conclusion for the etiology of this disease. In the present study we aimed to detect, quantify and do molecular analyses of M. hyopneumoniae strains in respiratory clinical samples recovered from healthy pigs and from those with pneumonia or other respiratory symptoms. The analytical sensitivity and specificity of PCR assays directed to Mollicutes detection and porcine mycoplasmas identification in clinical samples were evaluated. The identification of M. hyopneumoniae in the samples was performed using different molecular approaches, Multiplex PCR, Real Time PCR and Multilocus Variable-Number Tandem-Repeat amplification. Molecular characterization of the strains was achieved by determining and comparing the VNTR copy number directly in the samples. The highest number of samples positive to M. hyopneumoniae was identified by the multilocus VNTR amplification assay using labeled primers, followed by capillary electrophoresis. The highest concentration of M. hyopneumoniae was detected in pneumonic lungs (2, 3 * 108 genome copies /mL). The VNTR copy number analysis demonstrated that despite the high genetic variability of the M. hyopneumoniae strains, predominant strains in the swine farms could be identified by means of the VNTR copy number analysis of P97R1 and P146R3. (English)Molecular differences among Mycoplasma hyopneumoniae strains present in pneumonic lungs of swine have been largely studied. However, no comparative studies concerning the strains present in apparently healthy pigs have been carried out. This study aimed to detect, quantify and perform molecular analysis of M. hyopneumoniae strains in pig lungs with and without pneumonic lesions. The detection of M. hyopneumoniae was performed using multiplex PCR (YAMAGUTI, 2008), real-time PCR (STRAIT et al., 2008) and multiple VNTR amplification (VRANCKX et al., 2011). Molecular characterization of the strains was achieved by analysis of the VNTR copy number in P97R1, P146R3, H2R1 and H4. M. hyopneumoniae was detected in samples from healthy and pneumonic pigs and the amount of M. hyopneumoniae positive samples detected varied with the type of assay. The greater number of positive samples was identified by the multiple VNTR amplification combined with capillary electrophoresis. Using real-time PCR, 4.9*104 M. hyopneumoniae genome copies/mL was detected in apparently healthy lungs. A mean quantity of 3.9*106 M. hyopneumoniae genome copies/mL was detected in pneumonic lungs. The analysis of VNTR copy number demonstrated a high genetic variability of the M. hyopneumoniae strains present in apparently healthy and pneumonic lungs. Strains having 3 VNTR copy number in P97R1, were detected only in pneumonic lungs and strains having 40 and 43 VNTR copy number in P146R3 were detected only in apparently healthy lungs. Despite the genetic variability of M. hyopneumoniae, predominant strains in the swine farms could be identified.As diferenças moleculares entre as estirpes de Mycoplasma hyopneumoniae presentes em pulmões de suínos com pneumonia tem sido estudadas. Porém, estudos comparativos relativos as estirpes presentes nos suínos aparentemente saudáveis não foram levados a cabo. O objetivo do estudo foi a detecção, quantificação e analise molecular de M. hyopneumoniae nos pulmões suínos com e sem lesões pneumônicas. Para a detecção de M. hyopneumoniae usaramse o PCR Multiplo (YAMAGUTI, 2008), o PCR a Tempo Real (STRAIT et al., 2008) e a amplificação de múltiplo VNTR (VRANCKX et al., 2011). A caracterização molecular das estirpes foi realizada mediante a análise do número de copias de VNTR em P97R1, P146R3, H2R1 e H4. O M. hyopneumoniae foi detectado em amostras de suínos saudáveis e pneumônicos e a quantidade de M. hyopneumoniae nas amostras positivas variou com o tipo de ensaio. O maior número de amostras positivas foi identificado pela amplificação de múltiplas VNTR combinado com a eletroforese de capilares. Usando o PCR a Tempo Real, 4.9*104 copias de genoma/mL de M. hyopneumoniae foram detectadas em pulmões aparentemente saudáveis. Uma quantidade média de 3.9*106 copias de genoma/mL de M. hyopneumoniae foi detectada em pulmões pneumônicos. A análise do número de copias de VNTR demonstrou uma elevada variabilidade

Classifying organisms and artefacts by their outline shapes

We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields, such as evolutionary biology, structural biology, image processing and archaeology. However, mathematical shape spaces are rather complicated and nonlinear. The most widely used methods of shape analysis, geometric morphometrics, treat the shapes as sets of points. Diffeomorphic methods consider the underlying curve rather than points, but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, based on square-root velocity functions (SRVFs), outperforms all others, including a standard geometric morphometric method (eigenshapes), and that it is also superior to human experts using shape alone. When the SRVF approach is constrained to take account of homologous landmarks it can accurately classify objects of very different shapes. The SRVF method identifies a shortest path between shapes, and we show that this can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences.</p

Making connections: gap junctions are pivotal for MSCinduced long lasting survival of sensory neurons

The direct contact of Mesenchymal Stem Cells (MSCs) with Dorsal Root Ganglia sensory neurons is pivotal to prolong the neuronal survival and to support their maturation (1). Here we further investigated the mechanisms underlying this direct contact-mediated positive effect, focusing our attention on the possible interaction between MSCs and neurons, and in particular on gap junction formation. We set up direct co-cultures of MSCs and sensory neurons, and after 30 days we analyzed them. The electron microscopy analysis evidenced the presence of junctions between MSCs and neurons only in direct co-cultures. Using a diffusible dye, Calcein, we demonstrated a direct interaction among cells, with a flow of dye from MSCs to neurons. To confirm the importance of such a connection we blocked it by using a gap junction blocker, the carbenoxolone (2). The use of gap junction blocker induced a decrease of neuronal survival in co-culture, thus demonstrating the important role of gap junctions for the positive effect of MSCs. We are now investigating the possible exchanged molecules, focusing our attention on some pro-survival miRNA, such as miRNA 29b and miRNA 142-5 (3), in order to identify the molecule able to positively affect the neuronal survival

Differentiation of Mesenchymal Stem Cells towards an insulin-releasing phenotype after co-culture with Pancreatic Islets

Transplantation of pancreatic islets has become a promising clinical option to treat patients with type 1 diabetes, alternative to the standard therapy with insulin injections. Islet transplantation is a minimally invasive therapeutic approach, and it allows a better metabolic control and a long-term insulin independence in more than 80% of patients (Ryan et al., 2002). However this therapeutic treatment has some side effects, such as the poor yield of pancreatic islet explants and even more the immune graft rejection, which have as a consequence the very limited lifespan of transplanted pancreatic islets. To avoid these side effects several strategies have been proposed and, besides the treatment with immunosuppressive drugs, promising results have been obtained with the use of Mesenchymal Stem cells (MSCs), already known in literature to be able to support the survival of many cell types (Scuteri et al., 2006). Several in vivo studies have demonstrated that the concurrent transplantation of pancreatic islets with MSCs reduces the number of islets required to achieve glycemic control in diabetic rats, but the mechanisms of these encouraging results are still unknown (Figliuzzi et al., 2009). For these reasons in this in vitro study we characterized the effect of co-culture of rat MSC on survival and functioning of rat pancreatic islets, by evaluating for 4 weeks: i) MSC adhesion to pancreatic islets; ii) viability of pancreatic islets co-cultured with MSCs; iii) the expression of insulin after co-culture; iv) the ability of co-cultured pancreatic islets to correctly adjust insulin release after variation of glucose concentration. Our results demonstrated that MSCs are able to adhere to pancreatic islets, but to increase only partly the pancreatic islet survival, which retain the ability to express and correctly release insulin after glucose variation in medium culture. Noteworthy that the insulin level in the medium of co-cultured pancreatic islets is always higher with respect to medium of pancreatic islets alone. The immunofluorescence analysis reveals that also MSCs (and not only pancreatic islets) are able to express insulin, but only in co-culture. These results, which justify the in vivo observation reported above, suggest that MSCs undergo to differentiation into a insulin-releasing phenotype after co-culture with pancreatic islets. We are now evaluating the molecular mechanisms which drive this effect, by analyzing the role of soluble factors and of proteins able to induce insulin expression. This study was granted by MIUR – FIRB Futuro in Ricerca 2008 RBFR08VSVI_001

Informe sobre la producción científica de Cuba y El Caribe en revistas iberoamericanas de acceso abierto en redalyc.org 2005-2011

Objetivo: Proporcionar información sobre el Perfil de Producción Científica de Cuba y El Caribe en revistas del acervo redalyc.org para el periodo 2005-2011, a fin de conocer cuáles son tanto las tendencias como el comportamiento de las estrategias de comunicación y de colaboración que registran los artículos producidos por los investigadores cubanos y caribeños.Método: Se estudia la producción científica de 800 revistas iberoamericanas de acceso abierto durante 2005-2011, a partir de un modelo de análisis centrado en entidades de producción y comunicación, las cuales permiten generar un Perfil de Producción Científica según los indicadores de: Producción (P), Producción en Colaboración (PC) y Colaboración (C), aplicados a un núcleo de 145,515 artículos científicos que forman parte del acervo redalyc.org.Resultados: La información que constituye la producción científica de Cuba y El Caribe durante 2005-2011, forma parte de un estudio más amplio realizado al acervo redalyc.org, el cual abarca a 13,414 instituciones de 146 países. La producción de la región caribeña asciende a 7,967 artículos que corresponden a una aportación de 5.4% del total analizado, de estos, 23.8% fue publicado en revistas del extranjero, en tanto, 13.5% corresponden a ciencias sociales, 79% a ciencias, así como artes y humanidades con 0.5% y multidisciplinarias con 6.9%.En tanto, las instituciones caribeñas con mayor aporte a la producción científica son la Universidad de Ciencias Médicas de la Habana, la Universidad de la Habana y el Instituto de Ciencia Animal; mientras que 81% de los trabajos firmados por autores nacionales se han realizado en colaboración principalmente interna de tipo institucional (52.8%), y donde la participación de autores extranjeros se vincula principalmente con México, España, Brasil y Colombia que en conjunto representan 63.6% de la producción de la región caribeña en colaboración con otros países