Showing papers by "Federal University of Rio de Janeiro published in 2004"

Dynamic control of positional information in the early Drosophila embryo

Abstract: Morphogen gradients contribute to pattern formation by determining positional information in morphogenetic fields. Interpretation of positional information is thought to rely on direct, concentration-threshold-dependent mechanisms for establishing multiple differential domains of target gene expression. In Drosophila, maternal gradients establish the initial position of boundaries for zygotic gap gene expression, which in turn convey positional information to pair-rule and segment-polarity genes, the latter forming a segmental pre-pattern by the onset of gastrulation. Here we report, on the basis of quantitative gene expression data, substantial anterior shifts in the position of gap domains after their initial establishment. Using a data-driven mathematical modelling approach, we show that these shifts are based on a regulatory mechanism that relies on asymmetric gap-gap cross-repression and does not require the diffusion of gap proteins. Our analysis implies that the threshold-dependent interpretation of maternal morphogen concentration is not sufficient to determine shifting gap domain boundary positions, and suggests that establishing and interpreting positional information are not independent processes in the Drosophila blastoderm.

Interferon regulatory factor 6 (IRF6) gene variants and the risk of isolated cleft lip or palate.

Abstract: Background Cleft lip or palate (or the two in combination) is a common birth defect that results from a mixture of genetic and environmental factors. We searched for a specific genetic factor contributing to this complex trait by examining large numbers of affected patients and families and evaluating a specific candidate gene. Methods We identified the gene that encodes interferon regulatory factor 6 (IRF6) as a candidate gene on the basis of its involvement in an autosomal dominant form of cleft lip and palate, Van der Woude's syndrome. A single-nucleotide polymorphism in this gene results in either a valine or an isoleucine at amino acid position 274 (V274I). We carried out transmission-disequilibrium testing for V274I in 8003 individual subjects in 1968 families derived from 10 populations with ancestry in Asia, Europe, and South America, haplotype and linkage analyses, and case–control analyses, and determined the risk of cleft lip or palate that is associated with genetic variation in IRF6. Results ...

Prevalence of intra-abdominal hypertension in critically ill patients: a multicentre epidemiological study.

Abstract: Although intra-abdominal hypertension (IAH) can cause dysfunction of several organs and raise mortality, little information is available on the incidence and risk factors for IAH in critically ill patients This study assessed the prevalence of IAH and its risk factors in a mixed population of intensive care patients A multicentre, prospective 1-day point-prevalence epidemiological study conducted in 13 ICUs of six countries None Ninety-seven patients admitted for more than 24 h to one of the ICUs during the 1-day study period Intra-abdominal pressure (IAP) was measured four times (every 6 h) by the bladder pressure method Data included the demographics, medical or surgical type of admission, SOFA score, etiological factors such as abdominal surgery, haemoperitoneum, abdominal infection, massive fluid resuscitation, and ileus and predisposing conditions such as hypothermia, acidosis, polytransfusion, coagulopathy, sepsis, liver dysfunction, pneumonia and bacteraemia We enrolled 97 patients, mean age 64±15 years, 57 (59%) medical and 40 (41%) surgical admission, SOFA score of 65±40 Mean IAP was 98±47 mmHg The prevalence of IAH (defined as IAP 12 mmHg or more) was 505 and 82% had abdominal compartment syndrome (defined as IAP 20 mmHg or more) The only risk factor significantly associated with IAH was the body mass index, while massive fluid resuscitation, renal and coagulation impairment were at limit of significance Although we found a quite high prevalence of IAH, no risk factors were reliably associated with IAH; consequently, to get valid information about IAH, IAP needs to be measured

Toll‐like receptor 2‐dependent bacterial sensing does not occur via peptidoglycan recognition

Abstract: Toll-like receptor 2 (TLR2) has been shown to recognize several classes of pathogen-associated molecular patterns including peptidoglycan (PG). However, studies linking PG with TLR2 recognition have relied mainly on the use of commercial Staphylococcus aureus PG and have not addressed TLR2 recognition of other PG types. Using highly purified PGs from eight bacteria (Escherichia coli, Pseudomonas aeruginosa, Yersinia pseudotuberculosis, Helicobacter pylori, Bacillus subtilis, Listeria monocytogenes, Streptococcus pneumoniae and S. aureus), we show that these PGs are not sensed through TLR2, TLR2/1 or TLR2/6. PG sensing is lost after removal of lipoproteins or lipoteichoic acids (LTAs) from Gram-negative and Gram-positive cell walls, respectively. Accordingly, purified LTAs are sensed synergistically through TLR2/1. Finally, we show that elicited peritoneal murine macrophages do not produce tumour necrosis factor-alpha or interleukin-6 in response to purified PGs, suggesting that PG detection is more likely to occur intracellularly (through Nod1/Nod2) rather than from the extracellular compartment.

Treatment for adult HIV infection: 2004 recommendations of the International AIDS Society-USA Panel.

Abstract: ContextSubstantial changes in the field of human immunodeficiency virus (HIV) treatment have occurred in the last 2 years, prompting revision of the guidelines for antiretroviral management of adults with established HIV infection.ObjectiveTo update recommendations for physicians who provide HIV care regarding when to start antiretroviral therapy, what drugs to start with, when to change drug regimens, and what drug regimens to switch to after therapy fails.Data SourcesEvidence was identified and reviewed by a 16-member noncompensated panel of physicians with expertise in HIV-related basic science and clinical research, antiretroviral therapy, and HIV patient care. The panel was designed to have broad US and international representation for areas with adequate access to antiretroviral management.Study SelectionEvidence considered included published basic science, clinical research, and epidemiological data (identified by experts in the field or extracted through MEDLINE searches using terms relevant to antiretroviral therapy) and abstracts from HIV-oriented scientific conferences between July 2002 and May 2004.Data ExtractionData were reviewed to identify any information that might change previous guidelines. Based on panel discussion, guidelines were drafted by a writing committee and discussed by the panel until consensus was reached.Data SynthesisFour antiretroviral drugs recently have been made available and have broadened the options for initial and subsequent regimens. New data allow more definitive recommendations for specific drugs or regimens to include or avoid, particularly with regard to initial therapy. Recommendations are rated according to 7 evidence categories, ranging from I (data from prospective randomized clinical trials) to VII (expert opinion of the panel).ConclusionFurther insights into the roles of drug toxic effects, drug resistance, and pharmacological interactions have resulted in additional guidance for strategic approaches to antiretroviral management.

Polymerase chain reaction–based analysis of microorganisms associated with failed endodontic treatment

Abstract: Objective In this study, we aimed to investigate the occurrence of several microbial species in cases of failed endodontic therapy by means of the polymerase chain reaction (PCR). Study design Root canal samples were taken from 22 root-filled teeth with persistent periradicular lesions selected for re-treatment. DNA was extracted from the samples and analyzed for the presence of 19 microbial taxa by using the polymerase chain reaction. Results All samples were positive for at least 1 of the target microbial species. Enterococcus faecalis was the most prevalent species—detected in 77% of the cases. The other most prevalent species were Pseudoramibacter alactolyticus (52%), Propionibacterium propionicum (52%), Dialister pneumosintes (48%), and Filifactor alocis (48%). Candida albicans was found in 9% of the samples. The mean number of species in samples filled up to 2 mm short of the radiographic apex was 3 (range, 1-5), whereas cases in which the filling was greater than 2 mm from the apex yielded a mean of 5 species (range, 2-11). This difference was statistically significant (P Conclusions Microorganisms occurred in all cases of root-filled teeth associated with periradicular lesions, which lends strong support to the assertion that treatment failures are rather of infectious etiology, caused by persistent or secondary intraradicular infections. E faecalis was the most prevalent species, followed by 4 other anaerobic species: P alactolyticus, P propionicum, D pneumosintes, and F alocis. All examined samples harbored at least 1 of the following gram-positive bacterial species: E faecalis, P alactolyticus, or P propionicum.

Strategic Management of Technological Innovation

Abstract: Chapter 1 - Introduction Part One - Industry Dynamics of Technological Innovation Chapter 2 - Sources of Innovation Chapter 3 - Types and Patterns of Innovation Chapter 4 - Standards Battles and Design Dominance Chapter 5 - Timing of Entry Part Two - Formulating Technological Innovation Strategy Chapter 6 - Defining the Organization's Strategic Direction Chapter 7 - Choosing Innovation Projects Chapter 8 - Collaboration Strategies Chapter 9 - Protecting Innovation Part Three - Implementing Technological Innovation Strategy Chapter 10 - Organizing for Innovation Chapter 11 - Managing the New Product Development Process Chapter 12 - Managing New Product Development Teams Chapter 13 - Crafting a Deployment Strategy

The end of unified dark matter

Abstract: Despite the interest in dark matter and dark energy, it has never been shown that they are in fact two separate substances. We provide the first strong evidence that they are separate by ruling out a broad class of so-called unified dark matter models that have attracted much recent interest. We find that they produce oscillations or exponential blowup of the dark matter power spectrum inconsistent with observation. For the particular case of generalized Chaplygin gas models, 99.999% of the previously allowed parameter space is excluded, leaving essentially only the standard $\ensuremath{\Lambda}\mathrm{CDM}$ limit allowed.

Nonstationary Multivariate Process Modeling through Spatially Varying Coregionalization

Abstract: Models for the analysis of multivariate spatial data are receiving increased attention these days. In many applications it will be preferable to work with multivariate spatial processes to specify such models. A critical specification in providing these models is the cross covariance function. Constructive approaches for developing valid cross-covariance functions offer the most practical strategy for doing this. These approaches include separability, kernel convolution or moving average methods, and convolution of covariance functions. We review these approaches but take as our main focus the computationally manageable class referred to as the linear model of coregionalization (LMC). We introduce a fully Bayesian development of the LMC. We offer clarification of the connection between joint and conditional approaches to fitting such models including prior specifications. However, to substantially enhance the usefulness of such modelling we propose the notion of a spatially varying LMC (SVLMC) providing a very rich class of multivariate nonstationary processes with simple interpretation. We illustrate the use of our proposed SVLMC with application to more than 600 commercial property transactions in three quite different real estate markets, Chicago, Dallas and San Diego. Bivariate nonstationary process models are developed for income from and selling price of the property.

Support vector machines for transient stability analysis of large-scale power systems

Abstract: The pattern recognition approach to transient stability analysis (TSA) has been presented as a promising tool for online application. This paper applies a recently introduced learning-based nonlinear classifier, the support vector machine (SVM), showing its suitability for TSA. It can be seen as a different approach to cope with the problem of high dimensionality. The high dimensionality of power systems has led to the development and implementation of feature selection techniques to make the application feasible in practice. SVMs' theoretical motivation is conceptually explained and they are tested with a 2684-bus Brazilian system. Aspects of model adequacy, training time, classification accuracy, and dimensionality reduction are discussed and compared to stability classifications provided by multilayer perceptrons.

Motor activation prior to observation of a predicted movement.

Abstract: Previous research has shown that some of the same motor regions are activated both when performing and when observing a movement. Here we demonstrate in human subjects that such motor activity also occurs prior to observing someone else's action. This suggests that the mere knowledge of an upcoming movement is sufficient to excite one's own motor system, enabling people to anticipate, rather than react to, others' actions.

Versão resumida da "job stress scale": adaptação para o português

Abstract: OBJETIVO: Descrever o processo de adaptacao, para o portugues, da versao resumida da "job stress scale", originalmente elaborada em ingles. METODOS: Foram avaliados seis aspectos de equivalencia entre a escala original e a versao para o portugues: as equivalencias conceitual, semântica, operacional, de itens, de medidas e funcional. Tomou-se por base um estudo de confiabilidade teste-reteste com 94 individuos selecionados. RESULTADOS: O estudo de confiabilidade teste-reteste entre 94 individuos permitiu estimativas de reprodutibilidade (coeficientes de correlacao intraclasse) para as dimensoes de "demanda", "controle" e "apoio social" da escala de 0,88, 0,87 e 0,85, respectivamente. Para as mesmas dimensoes, as estimativas de consistencia interna (alpha de Cronbach) foram, respectivamente, 0,79, 0,67 e 0,85. CONCLUSOES: Os resultados sugerem que o processo de adaptacao da escala foi bem sucedido, indicando que seu uso no contexto sociocultural da populacao de estudo (Estudo Pro-Saude) e apropriado.

Gas physics, disk fragmentation, and bulge formation in young galaxies

Abstract: We investigate the evolution of star-forming gas-rich disks, using a 3D chemodynamical model including a dark halo, stars, and a two-phase interstellar medium with feedback processes from the stars. We show that galaxy evolution proceeds along very different routes depending on whether it is the gas disk or the stellar disk which first becomes unstable, as measured by the respective Q-parameters. This in turn depends on the uncertain efficiency of energy dissipation of the cold cloud component from which stars form. When the cold gas cools efficiently and drives the instability, the galactic disk fragments and forms a number of massive clumps of stars and gas. The clumps spiral to the center of the galaxy in a few dynamical times and merge there to form a central bulge component in a strong starburst. When the kinetic energy of the cold clouds is dissipated at a lower rate, stars form from the gas in a more quiescent mode, and an instability only sets in at later times, when the surface density of the stellar disk has grown sufficiently high. The system then forms a stellar bar, which channels gas into the center, evolves, and forms a bulge whose stars are the result of a more extended star formation history. We investigate the stability of the gas-stellar disks in both regimes, as well as the star formation rates and element enrichment. We study the morphology of the evolving disks, calculating spatially resolved colours from the distribution of stars in age and metallicity, including dust absorption. We then discuss morphological observations such as clumpy structures and chain galaxies at high redshift as possible signatures of fragmenting, gas-rich disks. Finally, we investigate abundance ratio distributions as a means to distinguish the different scenarios of bulge formation.

Conventional taxonomy obscures deep divergence between Pacific and Atlantic corals

Abstract: Only 17% of 111 reef-building coral genera and none of the 18 coral families with reef-builders are considered endemic to the Atlantic, whereas the corresponding percentages for the Indo-west Pacific are 76% and 39%1,2. These figures depend on the assumption that genera and families spanning the two provinces belong to the same lineages (that is, they are monophyletic). Here we show that this assumption is incorrect on the basis of analyses of mitochondrial and nuclear genes. Pervasive morphological convergence at the family level has obscured the evolutionary distinctiveness of Atlantic corals. Some Atlantic genera conventionally assigned to different families are more closely related to each other than they are to their respective Pacific ‘congeners’. Nine of the 27 genera of reef-building Atlantic corals belong to this previously unrecognized lineage, which probably diverged over 34 million years ago. Although Pacific reefs have larger numbers of more narrowly distributed species, and therefore rank higher in biodiversity hotspot analyses3, the deep evolutionary distinctiveness of many Atlantic corals should also be considered when setting conservation priorities.

Fusarium Infection in Hematopoietic Stem Cell Transplant Recipients

Abstract: To characterize the epidemiology and prognostic factors of invasive fusariosis in hematopoietic stem cell transplant (HSCT) recipients, the records of HSCT recipients from 9 hospitals (7 in Brazil and 2 in the United States) were retrospectively reviewed. Sixty-one cases were identified: 54 in allogeneic HSCT recipients and 7 in autologous HSCT recipients. The incidence of fusariosis among allogeneic HSCT recipients varied between a range of 4.21-5.0 cases per 1000 in human leukocyte antigen (HLA)--matched related transplant recipients to 20.19 cases per 1000 in HLA-mismatched transplant recipients. The median time period between transplantation and diagnosis of fusariosis was 48 days. Among allogeneic HSCT recipients, a trimodal distribution was observed: a first peak before engraftment, a second peak at a median of 62 days after transplantation, and a third peak >1 year after transplantation. The actuarial survival was 13% (median, 13 days). Persistent neutropenia was the single prognostic factor for death identified by multivariate analysis.

Programmed cell deaths

Abstract: Programmed cell death is a major component of both normal development and disease. The roles of cell death during either embryogenesis or pathogenesis, the signals that modulate this event, and the mechanisms of cell demise are the major subjects that drive research in this field. Increasing evidence obtained both in vitro and in vivo supports the hypothesis that a variety of cell death programs may be triggered in distinct circumstances. Contrary to the view that caspase-mediated apoptosis represents the standard programmed cell death, recent studies indicate that an apoptotic morphology can be produced independent of caspases, that autophagic execution pathways of cell death may be engaged without either the involvement of caspases or morphological signs of apoptosis, and that even the necrotic morphology of cell death may be consistently produced in some cases, including certain plants. Alternative cell death programs may imply novel therapeutic targets, with important consequences for attempts to treat diseases associated with disregulated programmed cell death.

ECLAMC: The Latin-American Collaborative Study of Congenital Malformations

Abstract: Definition: ECLAMC (‘Estudio Colaborativo Latino Americano de Malformaciones Congenitas’) is a program for the clinical and epidemiological investigation of risk factors in the etio

The homeotic protein AGAMOUS controls microsporogenesis by regulation of SPOROCYTELESS

Abstract: The Arabidopsis homeotic gene AGAMOUS (AG) is necessary for the specification of reproductive organs (stamens and carpels) during the early steps of flower development. AG encodes a transcription factor of the MADS-box family that is expressed in stamen and carpel primordia. At later stages of development, AG is expressed in distinct regions of the reproductive organs. This suggests that AG might function during the maturation of stamens and carpels, as well as in their early development. However, the developmental processes that AG might control during organogenesis and the genes that are regulated by this factor are largely unknown. Here we show that microsporogenesis, the process leading to pollen formation, is induced by AG through activation of the SPOROCYTELESS gene (SPL, also known as NOZZLE,NZZ), a regulator of sporogenesis. Furthermore, we demonstrate that SPL can induce microsporogenesis in the absence of AG function, suggesting that AG controls a specific process during organogenesis by activating another regulator that performs a subset of its functions.

Cat-Transmitted Sporotrichosis Epidemic in Rio de Janeiro, Brazil: Description of a Series of Cases

Abstract: Sporotrichosis is the most common subcutaneous mycosis in South America. Classic infection is associated with traumatic inoculation of soil, vegetables, and organic matter contaminated with Sporothrix schenckii. Zoonotic transmission has been described in isolated cases or in small outbreaks. Since 1998, we have been observing an increasing number of cases of sporotrichosis in persons from the city of Rio de Janeiro, Brazil, and surroundings. From 1998 to 2001, 178 cases of culture-proven sporotrichosis had been diagnosed. Female patients predominated, and the median age was 39 years. The most frequent clinical presentation was lymphocutaneous disease. Of the 178 patients, 156 reported domiciliary or professional contact with cats with sporotrichosis, and 97 of these patients had a history of receipt of cat scratch or bite. The patients received itraconazole as first-line treatment. This study suggests that feline transmission of sporotrichosis was associated with a large and long-lasting outbreak of the disease in Rio de Janeiro.

Dynamical analysis of regulatory interactions in the gap gene system of Drosophila melanogaster.

Abstract: Genetic studies have revealed that segment determination in Drosophila melanogaster is based on hierarchical regulatory interactions among maternal coordinate and zygotic segmentation genes. The gap gene system constitutes the most upstream zygotic layer of this regulatory hierarchy, responsible for the initial interpretation of positional information encoded by maternal gradients. We present a detailed analysis of regulatory interactions involved in gap gene regulation based on gap gene circuits, which are mathematical gene network models used to infer regulatory interactions from quantitative gene expression data. Our models reproduce gap gene expression at high accuracy and temporal resolution. Regulatory interactions found in gap gene circuits provide consistent and sufficient mechanisms for gap gene expression, which largely agree with mechanisms previously inferred from qualitative studies of mutant gene expression patterns. Our models predict activation of Kr by Cad and clarify several other regulatory interactions. Our analysis suggests a central role for repressive feedback loops between complementary gap genes. We observe that repressive interactions among overlapping gap genes show anteroposterior asymmetry with posterior dominance. Finally, our models suggest a correlation between timing of gap domain boundary formation and regulatory contributions from the terminal maternal system.

Greenhouse Gas Emissions from Hydroelectric Reservoirs in Tropical Regions

Abstract: This paper discusses emissions by power-dams in the tropics. Greenhouse gas emissions from tropical power-dams are produced underwater through biomass decomposition by bacteria. The gases produced in these dams are mainly nitrogen, carbon dioxide and methane. A methodology was established for measuring greenhouse gases emitted by various power-dams in Brazil. Experimental measurements of gas emissions by dams were made to determine accurately their emissions of methane (CH4) and carbon dioxide (CO2) gases through bubbles formed on the lake bottom by decomposing organic matter, as well as rising up the lake gradient by molecular diffusion.The main source of gas in power-dams reservoirs is the bacterial decomposition (aerobic and anaerobic) of autochthonous and allochthonous organic matter that basically produces CO2 and CH4. The types and modes of gas production and release in the tropics are reviewed.

Macrophage Interactions with Neutrophils Regulate Leishmania major Infection

Abstract: Macrophages are host cells for the pathogenic parasite Leishmania major . Neutrophils die and are ingested by macrophages in the tissues. We investigated the role of macrophage interactions with inflammatory neutrophils in control of L. major infection. Coculture of dead exudate neutrophils exacerbated parasite growth in infected macrophages from susceptible BALB, but killed intracellular L. major in resistant B6 mice. Coinjection of dead neutrophils amplified L. major replication in vivo in BALB, but prevented parasite growth in B6 mice. Neutrophil depletion reduced parasite load in infected BALB, but exacerbated infection in B6 mice. Exacerbated growth of L. major required PGE2 and TGF-β production by macrophages, while parasite killing depended on neutrophil elastase and TNF-α production. These results indicate that macrophage interactions with dead neutrophils play a previously unrecognized role in host responses to L. major infection.

Catalytic Conversion of Terpenes into Fine Chemicals

Abstract: This work reviews the use of terpenes available from renewable resources in the fine chemicals industry. Different products and processes are discussed. Transformations of terpenes involving isomerization, hydration, condensation, hydroformylation, hydrogenation, cyclization, oxidation, rearrangement, and ring contraction/enlargement are routes to produce a variety of compounds of interest to the pharmaceutical, agrochemical, and flavors and fragrances industries.