Determinants of mortality in oncology patients colonized or infected with Staphylococcus aureus

Oxacillin-resistant Staphylococcus aureus (ORSA) infection is an important cause of hospital morbidity and mortality. The objective of this study was to identify the main factors associated with death in patients colonized or infected with Staphylococcus aureus in a cancer center. A matched-pair case-control study enrolled all patients infected or colonized with ORSA (cases) admitted to the Hospital do Câncer in Rio de Janeiro from 01/01/1992 to 12/31/1994. A control was defined as a patient hospitalized during the same period as the case-patients and colonized or infected with oxacillin-susceptible Staphylococcus aureus (OSSA). The study enrolled 95 cases and 95 controls. Patient distribution was similar for the two groups (p > or = 0.05) with respect to gender, underlying diseases, hospital transfer, prior infection, age, temperature, heart and respiratory rates, neutrophil count, and duration of hospitalization. Univariate analysis of putative risk factors associated with mortality showed the following significant variables: admission to the intensive care unit (ICU), presence of bacteremia, use of central venous catheter (CVC), ORSA colonization or infection, pneumonia, use of urinary catheter, primary lung infection, prior use of antibiotics, mucositis, and absence of cutaneous abscesses. Multivariate analysis showed a strong association between mortality and the following independent variables: admission to ICU (OR [odds ratio]=7.2), presence of Staphylococcus bacteremia (OR=6.8), presence of CVC (OR=5.3), and isolation of ORSA (OR=2.7). The study suggests a higher virulence of ORSA in comparison to OSSA in cancer patients.

Helicobacter pylori genotyping from positive clotests in patients with duodenal ulcer

Even though the seroprevalence of H. pylori may be high in the normal population, a minority develops peptic ulcer. Colonization of the gastric mucosa by more pathogenic vacA strains of H. pylori seems to be associated with enhanced gastric inflammation and duodenal ulcer. H. pylori genotyping from positive CLOtests was developed to determine the vacA genotypes and cagA status in 40 duodenal ulcer patients and for routine use. The pathogenic s1b/ m1/ cagA genotype was the most frequently occurring strain (17/42.5%); only two (5%) patients presented the s2/ m2 genotype, the less virulent strain. Multiple strains were also detected in 17 (42.5%) patients. Multiple strains of H. pylori colonizing the human stomach have been underestimated, because genotyping has been performed from cultures of H. pylori. We concluded that genotyping of H. pylori from a positive CLOtest had the advantages of reducing the number of biopsies taken during endoscopy, eliminating the step of culturing H. pylori, and assuring the presence of H. pylori in the specimen being processed.

Necrotizing enterocolitis, pathogenesis and the protector effect of prenatal corticosteroids

Necrotizing enterocolitis is the most frequently occurring gastrointestinal disorder in premature neonates. Animal models of necrotizing enterocolitis and prenatal administration of cortisone have demonstrated that cortisone may accelerate maturation of the mucosal barrier, therefore reducing the incidence of this gastrointestinal disorder. The authors present a review of the literature of the most important risk factors associated with necrotizing enterocolitis, such as inflammatory gastrointestinal mediators, enteral feeding and bacterial colonization, and immaturity of the gastrointestinal barrier, and we emphasize the necessity for additional studies to explore the prenatal administration of cortisone as a preventive strategy for necrotizing enterocolitis.

Biofunctionalization of titanium surfaces for dental implants: osteogenic, anti-microbial and tribocorrosion resistant surfaces

PhD thesis in Biomedical Engineering

Changes in population and land use over time in the Ecuadorian Amazon

This paper draws upon a detailed longitudinal survey of households living on agricultural plots in the northern three provinces of the Ecuadorian Amazon, the principal region of colonization by migrants in Ecuador since the 1970s. Following the discovery of petroleum in 1967 near what has subsequently come to be the provincial capital and largest Amazonian city of Lago Agrio, oil companies built roads to lay pipelines to extract and pump oil across the Andes for export. As a result, for the past 30 years over half of both Ecuador's export earnings and government revenues have come from petroleum extracted from this region. But the roads also facilitated massive spontaneous in-migration of families from origin areas in the Ecuadorian Sierra, characterized by minifundia and rural poverty. This paper is about those migrants and their effects on the Amazonian landscape. We discuss the data collection methodology and summarize key results on settler characteristics and changes in population, land use, land ownership, technology, labor allocation, and living conditions, as well as the relationships between changes in population and changes in land use over time. The population in the study region has been growing rapidly due to both natural population growth (high fertility) and in-migration. This has led to a dramatic process of subdivision and fragmentation of plots in the 1990's, which contrasts with the consolidation of plots that has occurred in most of the mature frontier areas of the Brazilian Amazon. This fragmentation has led to important changes in land tenure and land use, deforestation, cattle raising, labor allocation, and settler welfare.

Da 'portugalidade' à lusofonia

Tese de Doutoramento em Ciências da Comunicação (Especialidade em Teoria da Cultura)

'Como seiva viva em tronco forte'. A agência noticiosa Lusitânia e o projeto imperial do Estado Novo

O presente estudo pretende descrever as condições políticas e sociais em que foi criada e se desenvolveu a Lusitânia, uma agência noticiosa portuguesa, destinada a contribuir para o fortalecimento do Império português através da difusão do noticiário colonial na metrópole e deste nas colónias. Apesar da escassez de estudos existentes e de não ser conhecido o paradeiro dos arquivos da agência, é possível ainda, através de fontes indiretas, avaliar da importância e do papel ideológico desta agência na construção de um Portugal uno do Minho a Timor, como pretendiam o regime e o fundador da agência, Luís Lupi.

Structural and successional variability of periphytic algal community in a Amazonian lake during the dry and rainy season (Rio Branco, Acre)

The colonization process and successional patterns of a periphytic algal community were evaluated in a Amazonian Viveiro Lake (Rio Branco, Acre, Brazil). Sampling was performed over a period of 35 days; at four-day intervals for 20 days, and then at five-day intervals. Water sampling for physical, chemical and biological analyses was done during the dry and rainy season. Glass slides were used as artificial substrates for periphyton colonization. The structural community was evaluated through population density, algae class, diversity indices and descriptive species. Species richness, diversity and evenness increased as succession progressed. While density of Bacillariophyceae, Euglenophyceae and Zygnemaphyceae increased with succession, Cyanobacteria remained dominant. Synechocystis aquatilis, Synechocystis diplococcus and Navicula pseudolanceolata were the main descriptive species in both the dry and rainy season. Cymbela tumida, Frustulia rhomboides, Trachelomonas lacustris and Closterium acicularis was correlated with an increase in hydrologic level during the rainy season. Conversely, the density of Chlamydomonas sp., Chroomonas nordstedtii, Trachelomonas volvocinopsis, Trachelomonas volvocina and Synechococcus linearis was correlated with an increase in water transparency during the dry season. In general, the periphytic algal community showed high diversity and species richness independent of season. Season also had little influence on representation of algae class and main descriptive species. However, successional patterns varied by season, and changes in hydrologic levels acted directly on the succession path of periphytic algae. More research on periphyton dynamics is needed to improve our understanding of tropical lake ecosystems, especially in Amazonian.

Spatial and temporal evolution of family-farming land use in the Tapajós region of the Brazilian Amazon

Pressures on the Brazilian Amazon forest have been accentuated by agricultural activities practiced by families encouraged to settle in this region in the 1970s by the colonization program of the government. The aims of this study were to analyze the temporal and spatial evolution of land cover and land use (LCLU) in the lower Tapajós region, in the state of Pará. We contrast 11 watersheds that are generally representative of the colonization dynamics in the region. For this purpose, Landsat satellite images from three different years, 1986, 2001, and 2009, were analyzed with Geographic Information Systems. Individual images were subject to an unsupervised classification using the Maximum Likelihood Classification algorithm available on GRASS. The classes retained for the representation of LCLU in this study were: (1) slightly altered old-growth forest, (2) succession forest, (3) crop land and pasture, and (4) bare soil. The analysis and observation of general trends in eleven watersheds shows that LCLU is changing very rapidly. The average deforestation of old-growth forest in all the watersheds was estimated at more than 30% for the period of 1986 to 2009. The local-scale analysis of watersheds reveals the complexity of LCLU, notably in relation to large changes in the temporal and spatial evolution of watersheds. Proximity to the sprawling city of Itaituba is related to the highest rate of deforestation in two watersheds. The opening of roads such as the Transamazonian highway is associated to the second highest rate of deforestation in three watersheds.

60,000 years of interactions between Central and Eastern Africa documented by major African mitochondrial haplogroup L2

Mitochondrial DNA (mtDNA) haplogroup L2 originated in Western Africa but is nowadays spread across the entire continent. L2 movements were previously postulated to be related to the Bantu expansion, but L2 expansions eastwards probably occurred much earlier. By reconstructing the phylogeny of L2 (44 new complete sequences) we provide insights on the complex net of within-African migrations in the last 60 thousand years (ka). Results show that lineages in Southern Africa cluster with Western/Central African lineages at a recent time scale, whereas, eastern lineages seem to be substantially more ancient. Three moments of expansion from a Central African source are associated to L2: (1) one migration at 70-50 ka into Eastern or Southern Africa, (2) postglacial movements (15-10 ka) into Eastern Africa; and (3) the southward Bantu Expansion in the last 5 ka. The complementary population and L0a phylogeography analyses indicate no strong evidence of mtDNA gene flow between eastern and southern populations during the later movement, suggesting low admixture between Eastern African populations and the Bantu migrants. This implies that, at least in the early stages, the Bantu expansion was mainly a demic diffusion with little incorporation of local populations.

Resolving the ancestry of Austronesian‑speaking populations

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The "out-of-Taiwan" model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion.

Effect of pH on Candida tropicalis virulence factors

Dissertação de mestrado em Bioengenharia

Influence of oxygen conditions on bacterial interactions within biofilms related with cystic fibrosis

Dissertação de mestrado em Bioengineering

Quantifying the legacy of the Chinese Neolithic on the maternal genetic heritage of Taiwan and Island Southeast Asia

There has been a long-standing debate concerning the extent to which the spread of Neolithic ceramics and Malay-Polynesian languages in Island Southeast Asia (ISEA) were coupled to an agriculturally driven demic dispersal out of Taiwan 4000 years ago (4 ka). We previously addressed this question using founder analysis of mitochondrial DNA (mtDNA) control-region sequences to identify major lineage clusters most likely to have dispersed from Taiwan into ISEA, proposing that the dispersal had a relatively minor impact on the extant genetic structure of ISEA, and that the role of agriculture in the expansion of the Austronesian languages was therefore likely to have been correspondingly minor. Here we test these conclusions by sequencing whole mtDNAs from across Taiwan and ISEA, using their higher chronological precision to resolve the overall proportion that participated in the "out-of-Taiwan" mid-Holocene dispersal as opposed to earlier, postglacial expansions in the Early Holocene. We show that, in total, about 20 % of mtDNA lineages in the modern ISEA pool result from the "out-of-Taiwan" dispersal, with most of the remainder signifying earlier processes, mainly due to sea-level rises after the Last Glacial Maximum. Notably, we show that every one of these founder clusters previously entered Taiwan from China, 6-7 ka, where rice-farming originated, and remained distinct from the indigenous Taiwanese population until after the subsequent dispersal into ISEA.

Insights into bacterial colony morphology evolution and diversification during infection development in cystic fibrosis

Tese de Doutoramento em Engenharia Biomédica.