Incidence of WHO stage 3 and 4 conditions following initiation of Anti-Retroviral Therapy in resource limited settings

To determine the incidence of WHO clinical stage 3 and 4 conditions during early anti-retroviral therapy (ART) in resource limited settings (RLS)

Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death

The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201

Risk factors associated with default from multi- and extensively drug-resistant tuberculosis treatment, uzbekistan: a retrospective cohort analysis.

The Médecins Sans Frontières project of Uzbekistan has provided multidrug-resistant tuberculosis treatment in the Karakalpakstan region since 2003. Rates of default from treatment have been high, despite psychosocial support, increasing particularly since programme scale-up in 2007. We aimed to determine factors associated with default in multi- and extensively drug-resistant tuberculosis patients who started treatment between 2003 and 2008 and thus had finished approximately 2 years of treatment by the end of 2010

Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

Optimal-Foraging Predator Favors Commensalistic Batesian Mimicry

BACKGROUND:Mimicry, in which one prey species (the Mimic) imitates the aposematic signals of another prey (the Model) to deceive their predators, has attracted the general interest of evolutionary biologists. Predator psychology, especially how the predator learns and forgets, has recently been recognized as an important factor in a predator-prey system. This idea is supported by both theoretical and experimental evidence, but is also the source of a good deal of controversy because of its novel prediction that in a Model/Mimic relationship even a moderately unpalatable Mimic increases the risk of the Model (quasi-Batesian mimicry). METHODOLOGY/PRINCIPAL FINDINGS:We developed a psychology-based Monte Carlo model simulation of mimicry that incorporates a "Pavlovian" predator that practices an optimal foraging strategy, and examined how various ecological and psychological factors affect the relationships between a Model prey species and its Mimic. The behavior of the predator in our model is consistent with that reported by experimental studies, but our simulation's predictions differed markedly from those of previous models of mimicry because a more abundant Mimic did not increase the predation risk of the Model when alternative prey were abundant. Moreover, a quasi-Batesian relationship emerges only when no or very few alternative prey items were available. Therefore, the availability of alternative prey rather than the precise method of predator learning critically determines the relationship between Model and Mimic. Moreover, the predation risk to the Model and Mimic is determined by the absolute density of the Model rather than by its density relative to that of the Mimic. CONCLUSIONS/SIGNIFICANCE:Although these predictions are counterintuitive, they can explain various kinds of data that have been offered in support of competitive theories. Our model results suggest that to understand mimicry in nature it is important to consider the likely presence of alternative prey and the possibility that predation pressure is not constant

Age-related decline in associative learning in healthy Chinese adults

10.1371/journal.pone.0080648PLoS ONE811-POLN

Prion protein interaction with soil humic substances: environmental implications

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative disorders caused by prions. Animal TSE include scrapie in sheep and goats, and chronic wasting disease (CWD) in cervids. Effective management of scrapie in many parts of the world, and of CWD in North American deer population is complicated by the persistence of prions in the environment. After shedding from diseased animals, prions persist in soil, withstanding biotic and abiotic degradation. As soil is a complex, multi-component system of both mineral and organic components, it is important to understand which soil compounds may interact with prions and thus contribute to disease transmission. Several studies have investigated the role of different soil minerals in prion adsorption and infectivity; we focused our attention on the interaction of soil organic components, the humic substances (HS), with recombinant prion protein (recPrP) material. We evaluated the kinetics of recPrP adsorption, providing a structural and biochemical characterization of chemical adducts using different experimental approaches. Here we show that HS act as potent anti-prion agents in prion infected neuronal cells and in the amyloid seeding assays: HS adsorb both recPrP and prions, thus sequestering them from the prion replication process. We interpreted our findings as highly relevant from an environmental point of view, as the adsorption of prions in HS may affect their availability and consequently hinder the environmental transmission of prion diseases in ruminants

Half-Time Strategies to Enhance Second-Half Performance in Team-Sports Players: A Review and Recommendations

The competitive demands of numerous intermittent team sports require that two consecutive periods of play are separated by a half-time break. Typically, half-time allows players to: return to the changing rooms, temporarily relax from the cognitive demands of the first half of match-play, rehydrate, re-fuel, attend to injury or equipment concerns, and to receive tactical instruction and coach feedback in preparation for the second half. These passive practices have been associated with physiological changes which impair physical and cognitive performance in the initial stages of the second half. An increased risk of injury has also been observed following half-time. On the day of competition, modification of half-time practices may therefore provide Sports Scientists and Strength and Conditioning Coaches with an opportunity to optimise second half performance. An overview of strategies that may benefit team sports athletes is presented; specifically, the efficacy of: heat maintenance strategies (including passive and active methods), hormonal priming (through video feedback), post-activation potentiation, and modified hydro-nutritional practices are discussed. A theoretical model of applying these strategies in a manner that compliments current practice is also presented

Effects of dietary Na+ deprivation on epithelial Na+ channel (ENaC), BDNF, and TrkB mRNA expression in the rat tongue

<p>Abstract</p> <p>Background</p> <p>In rodents, dietary Na⁺deprivation reduces gustatory responses of primary taste fibers and central taste neurons to lingual Na⁺stimulation. However, in the rat taste bud cells Na⁺deprivation increases the number of amiloride sensitive epithelial Na⁺channels (ENaC), which are considered as the "receptor" of the Na⁺component of salt taste. To explore the mechanisms, the expression of the three ENaC subunits (α, β and γ) in taste buds were observed from rats fed with diets containing either 0.03% (Na⁺deprivation) or 1% (control) NaCl for 15 days, by using <it>in situ </it>hybridization and real-time quantitative RT-PCR (qRT-PCR). Since BDNF/TrkB signaling is involved in the neural innervation of taste buds, the effects of Na⁺deprivation on BDNF and its receptor TrkB expression in the rat taste buds were also examined.</p> <p>Results</p> <p><it>In situ </it>hybridization analysis showed that all three ENaC subunit mRNAs were found in the rat fungiform taste buds and lingual epithelia, but in the vallate and foliate taste buds, only α ENaC mRNA was easily detected, while β and γ ENaC mRNAs were much less than those in the fungiform taste buds. Between control and low Na⁺fed animals, the numbers of taste bud cells expressing α, β and γ ENaC subunits were not significantly different in the fungiform, vallate and foliate taste buds, respectively. Similarly, qRT-PCR also indicated that Na⁺deprivation had no effect on any ENaC subunit expression in the three types of taste buds. However, Na⁺deprivation reduced BDNF mRNA expression by 50% in the fungiform taste buds, but not in the vallate and foliate taste buds. The expression of TrkB was not different between control and Na⁺deprived rats, irrespective of the taste papillae type.</p> <p>Conclusion</p> <p>The findings demonstrate that dietary Na⁺deprivation does not change ENaC mRNA expression in rat taste buds, but reduces BDNF mRNA expression in the fungiform taste buds. Given the roles of BDNF in survival of cells and target innervation, our results suggest that dietary Na⁺deprivation might lead to a loss of gustatory innervation in the mouse fungiform taste buds.</p

Rutas tróficas en macrozooplancton del Lago de Tota - Boyacá, Colombia

1 recurso en línea (56 páginas) : ilustraciones, figuras, tablas.In aquatic ecosystems inputs of matter and energy present in greater or lesser extent depending on the basin, given the origin and quality of these resources, you can alter the balance in metabolism or interactions in the food web. Using stable isotopes of carbon and nitrogen, the link between potential sources of funds and use established by macrozooplankton species in Lake Big and Lake Fellow the Lake Tota sectors. Trophic possible ways the role of each species in the proposed network, as well. In general, most of this study, most species have a bond with the autotrophic pathway, being the phytoplankton the food resource base for the food web, commonly found impoverished carbon signals. Particularly, the analysis showed a variation in the source or resource for two species (Daphnia laevis and Bosmina (Bosmina) cf. longirostris), with an enrichment in its signal to 19.92 ‰ -20.34 ‰ δ13C, which can be given by plasticity in their food supply, and even if Boeckella gracilis having a signal indicating a specialization in its appeal with carbon impoverished -30 to -26 ‰ values δ13C while nitrogen values are enriched with an average value 20.21 ‰ in δ15N. To set the trophic fractionation means establishing three groups, the first (herbivores) consisting of (D. laevis, B. (Bosmina) and Ceriodaphnia pulchella cf. longirostris), the second (omnivore) which is (Daphnia pulex, Macrocyclops sp. and Cyclopoida), and a third group (secondary consumer) where is the only calanoido B. gracilis. In comparing the temporal variation is observed that there is a significant change in signals δ13C and δ15N of some species in relation to the influence of sources and allochthonous or autochthonous origin, spatial variation was not significant. It is concluded that the macrozooplanton Lake Tota, has a strong link with the autotrophic pathway and pelagic trophic levels have 3 sections, plus the primary producers and the food web in general tends to have an amplitude of trophic niche.En los ecosistemas acuáticos se presentan aportes de materia y energía, en mayor o menor proporción dependiendo de su cuenca, dado el origen y calidad de estos recursos, se puede alterar el balance en el metabolismo o las interacciones en la red trófica. Utilizando los isotopos estables de Carbono y Nitrógeno, se estableció el vínculo entre fuentes potenciales de recursos y el uso por las especies del macrozooplancton en los sectores Lago grande y Lago chico del lago de Tota (Boyacá). Así, se propusieron las posibles vías tróficas y el rol de cada especie en la red. En general, en la mayor parte de este estudio, las especies tuvieron un vínculo marcado con la vía autotrófica, siendo el fitoplancton el recurso alimenticio base para la red trófica, encontrando comúnmente señales empobrecidas de carbono. Particularmente, el análisis mostró una variación en la fuente o recurso para dos especies (Daphnia laevis y Bosmina (Bosmina) cf. longirostris), con un enriquecimiento en su señal de 19.92‰ δ13C a -20.34‰ δ13C, lo que se puede dar por una plasticidad en su fuente alimenticia, e incluso el caso de Boeckella gracilis que tiene una señal que indica una especialización en su recurso con valores empobrecidos de carbono -30 a -26‰ δ13C mientras que los valores de nitrógeno son enriquecidos con un valor promedio de 20.21‰ en δ15N. Para establecer el fraccionamiento trófico medio se formaron tres grupos, el primero (herbívoros) conformado por (D. laevis, B. (Bosmina) cf. longirostris y Ceriodaphnia pulchella), el segundo (omnívoro) en el que se encuentra (Daphnia pulex, Macrocyclops sp. y Cyclopoida), y un tercer grupo (Consumidor secundario) donde esta B. gracilis el único calanoido. En la comparación de la variación temporal, se observa que hay un cambio significativo en las señales de δ13C y δ15N de algunas especies en relación a la influencia de las fuentes y su origen alóctono o autóctono, la variación espacial no fue significativa. Se concluye que el macrozooplanton del lago de Tota, tiene un fuerte vínculo con la vía autotrófica y que los niveles tróficos pelágicos tienen 3 eslabones, más los productores primarios, y la red trófica en general tiende a tener una amplitud del nicho trófico. En los ecosistemas acuáticos se presentan aportes de materia y energía, en mayor o menor proporción dependiendo de su cuenca, dado el origen y calidad de estos recursos, se puede alterar el balance en el metabolismo o las interacciones en la red trófica. Utilizando los isotopos estables de Carbono y Nitrógeno, se estableció el vínculo entre fuentes potenciales de recursos y el uso por las especies del macrozooplancton en los sectores Lago grande y Lago chico del lago de Tota (Boyacá). Así, se propusieron las posibles vías tróficas y el rol de cada especie en la red. En general, en la mayor parte de este estudio, las especies tuvieron un vínculo marcado con la vía autotrófica, siendo el fitoplancton el recurso alimenticio base para la red trófica, encontrando comúnmente señales empobrecidas de carbono. Particularmente, el análisis mostró una variación en la fuente o recurso para dos especies (Daphnia laevis y Bosmina (Bosmina) cf. longirostris), con un enriquecimiento en su señal de 19.92‰ δ13C a -20.34‰ δ13C, lo que se puede dar por una plasticidad en su fuente alimenticia, e incluso el caso de Boeckella gracilis que tiene una señal que indica una especialización en su recurso con valores empobrecidos de carbono -30 a -26‰ δ13C mientras que los valores de nitrógeno son enriquecidos con un valor promedio de 20.21‰ en δ15N. Para establecer el fraccionamiento trófico medio se formaron tres grupos, el primero (herbívoros) conformado por (D. laevis, B. (Bosmina) cf. longirostris y Ceriodaphnia pulchella), el segundo (omnívoro) en el que se encuentra (Daphnia pulex, Macrocyclops sp. y Cyclopoida), y un tercer grupo (Consumidor secundario) donde esta B. gracilis el único calanoido. En la comparación de la variación temporal, se observa que hay un cambio significativo en las señales de δ13C y δ15N de algunas especies en relación a la influencia de las fuentes y su origen alóctono o autóctono, la variación espacial no fue significativa. Se concluye que el macrozooplanton del lago de Tota, tiene un fuerte vínculo con la vía autotrófica y que los niveles tróficos pelágicos tienen 3 eslabones, más los productores primarios, y la red trófica en general tiende a tener una amplitud del nicho trófico.Bibliografía: páginas 46-56.MaestríaMagíster en Ciencias Biológica