The indeterminate form of human chronic Chagas' disease: a clinical epidemological review

Data on the epidemiology and the natural history of the indeterminate form of human chronic Chagas' disease (IFCCD) are discussed, revealing its great importance in endemic areas of Brazil. The work shows that IFCCD presents a gradual and very slow course, causing a benign picture in the studied patients. Evolution patterns, prognostic and anatomopathological features are also discussed. For practical purposes, the classical concept of IFCCD proved to be simple, operational and consistent, It is defined by the absence of symptoms and clinical findings in chronic infected patients with positive serology and/or parasitological examinations for Trypanosoma cruzi coupled with normal electrocardiographic and radiological exams (heart, oesophagus and colon X-Rays). If a patient is submitted to more rigorous and sophisticated tests, these can reveal some alterations, generally small ones and unable to interfere with the prognosis of the infection. It is suggested that research lines specially related to the evolution ary factors and immunological involvement during this phase be adopted.

Acute mesenteric vein thrombosis: factors associated with evolution to chronic mesenteric vein thrombosis

OBJECTIVE. Acute mesenteric venous thrombosis signs at MDCT are well described, but the literature lacks studies assessing their evolution. We aimed to describe the radiologic evolution of isolated acute mesenteric venous thrombosis and associated prognostic factors. MATERIALS AND METHODS. Patients with isolated acute mesenteric venous thrombosis with follow-up for a minimum of 1 month with MDCT were selected. Images at the acute phase and on follow-up were reviewed in consensus reading. For acute mesenteric venous thrombosis, we searched for low-attenuated intraluminal filling defect. For chronic mesenteric venous thrombosis, we searched for vessel stenosis or occlusion associated with collateral mesenteric veins. Treatment, thrombosis risk factor, symptoms, location, and length and diameter of mesenteric venous thrombosis were reported and correlated with evolution over time. RESULTS. Twenty patients (nine women and 11 men; mean age, 52 years) were selected. Four patients recovered without radiologic sequelae, and 16 developed chronic mesenteric venous thrombosis signs. Anticoagulation did not influence recovery (p = 1). Patients with recovery compared with patients with chronic mesenteric venous thrombosis showed more frequent central lesions (p = 0.03). At diagnosis, the thrombosed segment was shorter and larger in the complete radiologic recovery group compared with the chronic mesenteric venous thrombosis signs group: mean length (± SD) 6.25 ± 3.21 cm and 12.81 ± 5.96 cm, respectively (p = 0.01); mean transverse diameter 1.82 ± 0.42 cm and 1.12 ± 0.34 cm, respectively (p = 0.01). Mesenteric fat infiltration at diagnosis was more frequent in the chronic mesenteric venous thrombosis signs group than in the complete recovery group (p = 0.03). CONCLUSION. Most cases of acute mesenteric venous thrombosis evolve toward the chronic form with vein stenosis or occlusion and development of collateral veins. Location, length of mesenteric venous thrombosis, transverse diameter of the vein, and mesenteric fat infiltration at diagnosis are determinant factors for mesenteric venous thrombosis evolution.

Factors that determine the evolution of high-growth businesses

The study herein discusses research aimed at elucidating the factors that contribute to a business' ability to maintain high growth. The database from the Iberian Balance Sheet Analysis System (SABI, from its initials in Spanish) was used to identify 250 industrial Catalonian businesses with high growth during 2004-2007. These companies participated in a survey on strategies and management practices; in 2013, they were re-analyzed to investigate the factors that contributed to continued growth for certain companies. Through diverse statistical techniques, business policies related to quality, innovation, internationalization and finance were shown to influence business growth and sustainability over time. High-growth businesses have been studied throughout the world, but this is the first study to investigate the evolution of businesses after a high-growth phase.

Evolution of the epithelial sodium channel and the sodium pump as limiting factors of aldosterone action on sodium transport.

Despite large changes in salt intake, the mammalian kidney is able to maintain the extracellular sodium concentration and osmolarity within very narrow margins, thereby controlling blood volume and blood pressure. In the aldosterone-sensitive distal nephron (ASDN), aldosterone tightly controls the activities of epithelial sodium channel (ENaC) and Na,K-ATPase, the two limiting factors in establishing transepithelial sodium transport. It has been proposed that the ENaC/degenerin gene family is restricted to Metazoans, whereas the α- and β-subunits of Na,K-ATPase have homologous genes in prokaryotes. This raises the question of the emergence of osmolarity control. By exploring recent genomic data of diverse organisms, we found that: 1) ENaC/degenerin exists in all of the Metazoans screened, including nonbilaterians and, by extension, was already present in ancestors of Metazoa; 2) ENaC/degenerin is also present in Naegleria gruberi, an eukaryotic microbe, consistent with either a vertical inheritance from the last common ancestor of Eukaryotes or a lateral transfer between Naegleria and Metazoan ancestors; and 3) The Na,K-ATPase β-subunit is restricted to Holozoa, the taxon that includes animals and their closest single-cell relatives. Since the β-subunit of Na,K-ATPase plays a key role in targeting the α-subunit to the plasma membrane and has an additional function in the formation of cell junctions, we propose that the emergence of Na,K-ATPase, together with ENaC/degenerin, is linked to the development of multicellularity in the Metazoan kingdom. The establishment of multicellularity and the associated extracellular compartment ("internal milieu") precedes the emergence of other key elements of the aldosterone signaling pathway.

Evolution of the Helvetic shelf (Switzerland) during the Barremian-early Aptian : paleoenvironmental, paleogeographic and paleoceanographic controlling factors

The Early Cretaceous has experienced the development of large shallow-water carbonate platform in tropical and subtropical regions, favoured by exceptionally warm climatic conditions, optimal trophic conditions and a suitable tectonic and paleogeographic context. This period was also characterized by shorter intervals, in which the widespread deposition of marine sediments enriched in organic matter occurred ("oceanic anoxic episodes": OAE). This study focuses on the Barremian- Aptian interval, during which the Urgonian platform developed throughout the northern Tethyan passive margin. Due to the Alpine orogeny, sediments belonging to this platform - named locally Schrattenkalk Formation, are presently outcropping in the Helvetic Alps. This study aims to reconstruct the paleogeographic evolution of the Helvetic platform, and to define the environmental and oceanographic factors, which influenced its development. Several key episodes in the life of this platform have been identified: - The installation of the platform, covering hemipelagic sediments of the Drusberg Member, near the limit between the early and late Barremian. - The temporary change of carbonate production type during the basal Aptian, with the deposition of the Rawil Member. - And finally the definitive interruption of photozoan carbonate platform sedimentation in the study area, during the early Aptian. The sedimentological, biostratigraphical and chemostratigraphic (8I3C) data lead to the sequential subdivision of eleven sections and one core, located throughout the different Helvetic nappes of Switzerland. The sequence stratigraphie framework, initially defined for the Urgonian carbonate platform of the Vercors area (SE France), is confirmed in the Helvetic nappes, where the same number of sequences was observed. Many similarities between these two areas are put forward in this work. The sequence stratigraphie framework helped to highlight the installation of a bioclastic body, included in the Schrattenkalk Formation, since the middle Early Barremian (sequence B2). The age of the installation of the rudist-rich limestone, which corresponds to the Urgonian facies sensu stricto, is attributed to the late Barremian (maximum flooding surface of the sequence B3). This age coincides with the one determined in other northern Tethyan areas for the installation of the Urgonian platform. The results of this study show a strong tectonic control of the platform architecture, with the presence of syn-sedimentary faults in a perpendicular position to the progradation direction of the platform. The presence of these faults was highlighted by the study of the evolution of the microfacies distribution and by thickness variations in different areas. Sea level fluctuations also played an important role in the various life phases of the platform. Three major falls in sea level have been identified. A significant emersion of the proximal domain has been observed, involving an important drop of the relative sea level, leading to the exposure of the Drusberg Member hemipelagic series. A second major drop in sea level is identified near the Barremian-Aptian boundary, and a third is registered on the top of the Upper Schrattenkalk Member on the whole platform; it is associated with a karst affecting the underlying limestones to a depth of over 20 meters. This observation sheds new light on the conditions linked to the demise of Urgonian platform, which was strongly influenced by this phase of emersion.

Factors influencing the evolution of e-commerce : an empirical analysis in a developed market economy

Peer-reviewed

Molecular Evolution of Metazoan Hypoxia-inducing Factors

Most metazoans rely on aerobic energy production, which is dependent on adequate oxygen supply. In the case of reduced oxygen supply (hypoxia), the most profound changes in gene expression are mediated by transcription factors named hypoxia-inducible factors (HIF alpha). These proteins are post-translationally regulated by prolyl-4-hydroxylase (PHD) enzymes that are direct “sensors” of cellular oxygen levels. This thesis examines the molecular evolution of metazoan HIF systems. In early metazoans the HIF system emerged from pre-existing PHD oxygen sensors and early bHLH-PAS transcription factors. In invertebrates our analysis revealed an unexpected diversity of PHD genes and HIF alpha sequence characteristics. An early branching vertebrate, the epaulette shark (Hemiscyllium ocellatum) was chosen for sequencing and hypoxia preconditioning studies of HIF alpha and PHD genes. As no quantitative PCR reference genes were available, this thesis includes the first study of reference genes in cartilaginous fish species. Applying multiple statistical analysis we also discoveredthat commonly used reference gene software may perform poorly with some data sets. Novel reference genes allowed accurate measurements of the mRNAlevels of the studied target genes. Cartilaginous fishes have three genomic duplicates of both HIF alpha and PHD genes like mammals and teleost fishes. Combining functional divergence and selection analyses it was possible to describe how sequence changes in both HIF alpha and PHD duplicates may have contributed to the differential oxygen sensitivityof HIF alphas. Additionally, novel teleost HIF-1 alpha sequences were produced and used to reveal the molecular evolution of HIF-1 alpha in this lineage rich with hypoxia tolerant species.

The role of biotic and abiotic factors in evolution of ant dispersal in the milkwort family (Polygalaceae)

A phylogenetic approach was taken to investigate the evolutionary history of seed appendages in the plant family Polygalaceae (Fabales) and determine which factors might be associated with evolution of elaiosomes through comparisons to abiotic (climate) and biotic (ant species number and abundance) timelines. Molecular datasets from three plastid regions representing 160 species were used to reconstruct a phylogenetic tree of the order Fabales, focusing on Polygalaceae. Bayesian dating methods were used to estimate the age of the appearance of ant-dispersed elaiosomes in Polygalaceae, shown by likelihood optimizations to have a single origin in the family. Topology-based tests indicated a diversification rate shift associated with appearance of caruncular elaiosomes. We show that evolution of the caruncular elaiosome type currently associated with ant dispersal occurred 54.0-50.5 million year ago. This is long after an estimated increase in ant lineages in the Late Cretaceous based on molecular studies, but broadly concomitant with increasing global temperatures culminating in the Late Paleocene-Early Eocene thermal maxima. These results suggest that although most major ant clades were present when elaiosomes appeared, the environmental significance of elaiosomes may have been an important factor in success of elaiosome-bearing lineages. Ecological abundance of ants is perhaps more important than lineage numbers in determining significance of ant dispersal. Thus, our observation that elaiosomes predate increased ecological abundance of ants inferred from amber deposits could be indicative of an initial abiotic environmental function.

Multimodel assessment of the factors driving stratospheric ozone evolution over the 21st century

The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from 14 chemistry‐climate models, driven by prescribed levels of halogens and greenhouse gases. There is general agreement among the models that total column ozone reached a minimum around year 2000 at all latitudes, projected to be followed by an increase over the first half of the 21st century. In the second half of the 21st century, ozone is projected to continue increasing, level off, or even decrease depending on the latitude. Separation into partial columns above and below 20 hPa reveals that these latitudinal differences are almost completely caused by differences in the model projections of ozone in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and is projected to return to 1960 levels well before the end of the century, although there is a spread among models in the dates that ozone returns to specific historical values. We find decreasing halogens and declining upper atmospheric temperatures, driven by increasing greenhouse gases, contribute almost equally to increases in upper stratospheric ozone. In the tropical lower stratosphere, an increase in upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in most of the models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century, returning to 1960 levels well before the end of the century in most models.

The evolution of international output differences (1960-2000): From factors to productivity

This article presents a group of exercises of level and growth decomposition of output per worker using cross-country data from 1960 to 2000. It is shown that at least until 1975 factors of production (capital and education) were the main source of output dispersion across economies and that productivity variance was considerably smaller than in late years. Only after this date the prominence of productivity started to show up in the data, as the majority of the literature has found. The growth decomposition exercises showed that the reversal of relative importance of productivity vis-a-vis factors is explained by the very good (bad) performance of productivity of fast (slow) growing economies. Although growth in the period, on average, is mostly due to factors accumulation, its variance is explained by productivity.

Sociodemographic and clinical characteristics, causal factors and evolution of a group of patients with chronic urticaria-angioedema

CONTEXTO E OBJETIVO: Urticária-angioedema crônico é enfermidade freqüente, complexa e multicausal. O objetivo foi estudar as características sociodemográficas, clínicas, os fatores causais, agravantes e a evolução da enfermidade. TIPO DE ESTUDO E LOCAL: Descritivo e prospectivo, realizado no ambulatório de Dermatologia da Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (Unesp). MÉTODOS: Foram avaliados pacientes com diagnóstico de urticária-angioedema crônico através de dados sociodemográficos, anamnese, exames dermatológico, clínico e laboratorial, com ênfase nos fatores causais, agravantes e na evolução da enfermidade. RESULTADOS: 125 pacientes foram incluídos, 95 mulheres e 30 homens. Predominaram mulheres de 30 a 40 anos e homens de 10 a 20 anos. A idade média foi de 35 anos para as mulheres e 32 anos para os homens. Predominaram pacientes de raça branca, residentes em zona urbana e casados. O tempo médio de doença foi de 45,6 meses e de cada lesão foi de 5,6 horas. A metade dos casos tinha surtos diariamente e associação de urticária com angioedema. Não houve horário preferencial de aparecimento dos surtos, mas o noturno foi o horário de piora mais citado. A causa foi esclarecida em 37,6%, predominando as infecções. O estresse foi o agravante mais referido. O tempo médio de acompanhamento foi de 11,7 meses e 60% evoluíram para o controle, 32% melhoraram, 9% mantiveram-se inalterados e um caso piorou. CONCLUSÕES: Urticária-angioedema ocorreu mais em mulheres de meia-idade. A causa foi esclarecida em um terço dos pacientes e metade deles teve controle da doença em aproximadamente um ano.

Factors related to the evolution of poverty in the Greater Buenos Aires, 1991-1997

Includes bibliography