Fast screening for diagnostic of heart ischemic episodes

Dissertação para obtenção do Grau de Doutor em Química Sustentável

Transitional dynamics of an endogenous growth model with an erosion effect

The convergence features of an Endogenous Growth model with Physical capital, Human Capital and R&D have been studied. We add an erosion effect (supported by empirical evidence) to this model, and fully characterize its convergence properties. The dynamics is described by a fourth-order system of differential equations. We show that the model converges along a one-dimensional stable manifold and that its equilibrium is saddle-path stable. We also argue that one of the implications of considering this “erosion effect” is the increase in the adherence of the model to data.

Serological screening and toxoplasmosis exposure factors among pregnant women in South of Brazil

Serological screening and evaluation of exposure factors for Toxoplasma gondii transmission were conducted in 2126 pregnant women from southern Brazil. Specific antibodies against Toxoplasma gondii were presented by 74.5% (n=1583) of the pregnant women evaluated. Contact with soil was found to be the major factor for infection.

Development of novel benzimidazole- based COX Inhibitors new synthetic strategies and screening of heterocyclic structures

Dissertação para obtenção do Grau de Doutor em Química, especialidade Química Orgânica

Dynamics and kinetics of natural killer cell cytotoxicity in human malaria as evaluated by a novel stepwise cytotoxicity assay

Malaria causes important functional alterations of the immune system, but several of them are poorly defined. To evaluate thoroughly the natural killer cell cytotoxicity in patients with malaria, we developed a technique capable to assess both the dynamics and the kinetics of the process. For the kinetics assay, human peripheral blood mononuclear cells were previously incubated with K562 cells and kept in agarose medium, while for the dynamics assay both cells were maintained in suspension. NK activity from patients with vivax malaria presented a kinetics profile faster than those with falciparum malaria. NK cytotoxicity positively correlated with parasitemia in falciparum malaria. The dynamics of NK cytotoxicity of healthy individuals was elevated at the beginning of the process and then significantly decreased. In contrast, malaria patients presented successive peaks of NK activity. Our results confirmed the occurrence of alteration in NK cell function during malaria, and added new data about the NK cytotoxicity process.

The dynamics of brand loyalty across a consumer’s lifetime

This project studies the Portuguese female fashion market. We intend to determine patterns of consumer brand loyalty across brands and ages. By interviewing 8 young adults and surveying 125 teens and 87 adults, we found that brands’ segmentation by usage per age segment is related with differentiation in brand loyalty and peer pressure. We also found that teens have higher attitudinal brand loyalty while adults have higher behavioral loyalty. Moreover, brand loyalty in teens is more susceptible to peer pressure. The results imply that customer relationship management strategies should be differentiated according to age segment. We also derive marketing implications with a focus on each brand’s loyalty profile.

Evaluation of the use of real-time PCR for human T cell lymphotropic virus 1 and 2 as a confirmatory test in screening for blood donors

INTRODUCTION: HTLV-1/2 screening among blood donors commonly utilizes an enzyme-linked immunosorbent assay (EIA), followed by a confirmatory method such as Western blot (WB) if the EIA is positive. However, this algorithm yields a high rate of inconclusive results, and is expensive. METHODS: Two qualitative real-time PCR assays were developed to detect HTLV-1 and 2, and a total of 318 samples were tested (152 blood donors, 108 asymptomatic carriers, 26 HAM/TSP patients and 30 seronegative individuals). RESULTS: The sensitivity and specificity of PCR in comparison with WB results were 99.4% and 98.5%, respectively. PCR tests were more efficient for identifying the virus type, detecting HTLV-2 infection and defining inconclusive cases. CONCLUSIONS: Because real-time PCR is sensitive and practical and costs much less than WB, this technique can be used as a confirmatory test for HTLV in blood banks, as a replacement for WB.

Standardization of an ELISA test using a recombinant nucleoprotein from the Junin virus as the antigen and serological screening for arenavirus among the population of Nova Xavantina, State of Mato Grosso

INTRODUCTION: Arenavirus hemorrhagic fever is a severe emerging disease. METHODS: Considering that the levels of antibodies against arenavirus in the Brazilian population are completely unknown, we have standardized an ELISA test for detecting IgG antibodies using a recombinant nucleoprotein from the Junin virus as the antigen. This protein was obtained by inserting the gene of the Junin virus nucleoprotein into the genome of Autographa californica nucleopolyhedrovirus, using the Bac-to-Bac baculovirus expression system. This recombinant baculovirus was used to infect S. frugiperda cells (SF9). RESULTS: The infection resulted in synthesis of high concentrations of recombinant protein. This protein was detected on 12.5% polyacrylamide gel and by means of Western blot. Using the standardized ELISA test, 343 samples from the population of Nova Xavantina were analyzed. We observed that 1.4% of the serum samples (five samples) presented antibody titers against arenavirus. CONCLUSIONS: These results show the population studied may present exposure to arenavirus infection.

Dynamics of Capillaria-hepatica-induced hepatic septal fibrosis in rats

INTRODUCTION: The pathogenesis of septal hepatic fibrosis, induced in rats by Capillaria hepatica infection, was studied with the aid of a large collection of stored paraffin blocks, representative of the different evolutive phases of fibrosis which appeared in 100% of infected rats. METHODS: Studies were conducted involving histology, immunohistochemistry, immunofluorescence and morphometric methods, in order to observe the dynamic behavior of the cellular and matrix components of fibrosis, over a one year period of evolution. RESULTS: Observation verified that septal fibrosis originates from several portal spaces simultaneously. Its origin and progression involve blood vessel proliferation (angiogenesis), multiplication of actin-positive cells (pericytes and myofibroblasts) and progressive collagen deposition. By the end of 4-5 months, a progressive decrease in all these components was observed, when signs of regression of septal fibrosis became more evident over time. CONCLUSIONS: Besides indicating the fundamental role played by angiogenesis in the pathogenesis of fibrosis, these morphological data concerning the dynamics of this C. hepatica experimental model proved to be adequate for future investigations regarding the functional aspects of fibrosis induction, progression and regression.

Learning new tricks: Corticostriatal dynamics during novel skill learning

Learning novel actions and skills is a prevalent ability across multiple species and a critical feature for survival and competence in a constantly changing world. Novel actions are generated and learned through a process of trial and error, where an animal explores the environment around itself, generates multiple patterns of behavior and selects the ones that increase the likelihood of positive outcomes. Proper adaptation and execution of the selected behavior requires the coordination of several biomechanical features by the animal. Cortico-basal ganglia circuits and loops are critically involved in the acquisition, learning and consolidation of motor skills.(...)

Firms and aggregate dynamics

We investigate the role of permanent and transitory shocks for firms and aggregate dynamics. We find that permanent shocks to productivity and permanent shifts in the composition of output explain at least four-fifths of firms’ dynamics. However, these permanent shocks are almost uncorrelated across firms and are therefore less relevant for aggregate dynamics. Transitory shocks, on the other hand, are not very important at the firm level,but they account for most of the volatility of aggregate hours and output, because they are significantly correlated across firms. Finally, we try to make some progress on the interpretation of the shocks.

Incidence of congenital toxoplasmosis in the city of Belém, state of Pará, northern Brazil, determined by a neonatal screening program: preliminary results

INTRODUCTION: The aim of this study was to determinate the incidence of congenital toxoplasmosis among a group of newborns (NBs) from Belém using neonatal screening. METHODS: Among the 6,000 newborns referred for investigation of genetic and metabolic diseases, 1,000 were selected for screening for congenital toxoplasmosis by determining the amount of IgM in the eluates of blood collected on filter paper. Positive tests were confirmed using paired serology of the NB and his mother. RESULTS: Out of the 1,000 NBs assessed, one had a positive screening result that was confirmed by paired serology. CONCLUSIONS: The incidence of congenital toxoplasmosis in Belém was 10/10,000 live NBs.

Spatial dynamics of urban populations of Lutzomyia longipalpis (Diptera: Psychodidae) in Caxias, State of Maranhão, Brazil

Introduction In this paper, we report the ecology of Lutzomyia longipalpis in Caxias City, located in the eastern part of State of Maranhão, Brazil and highlight its seasonal and geographical distribution by environment. In addition, we discuss natural Leishmania infection and its relationship with visceral leishmaniasis. Methods Between September 2007 and August 2009, the collection of sandflies was performed using Center for Disease Control (CDC) light traps from 15 houses in 5 selected neighborhoods. Results Lutzomyia longipalpis was present in all zones of the city. We also found that Lu. longipalpis was regularly detected both inside and around the house, predominantly in outdoor areas. In urban areas, Lu. longipalpis was present in both the dry and rainy seasons, with a higher density present in the latter. One female specimen of Lu. longipalpis was observed to have natural Leishmania infection. Conclusions The presence of Lu. longipalpis was observed throughout the year during 2 seasonal periods, with a predominance in the rainy season. A low rate of natural Leishmania infection was observed in urban areas during the rainy season.

Schistosomiasis mansoni in urban Northeast Brazil: influence of rainfall regime on the population dynamics of Biomphalaria sp.

Introduction Our objective was to evaluate the influence of rainfall regime on the population dynamics of Biomphalaria in a potential urban focus of schistosomiasis in Aracaju, Brazil, during 2009-2010. Methods Snails were collected monthly and were counted, measured and identified; the level of infection and fecal contamination at the sampling sites was determined; rainfall data were obtained. Results High levels of fecal contamination were observed, and the abundance of Biomphalaria glabrata increased during the rainy and post-rainy seasons. The snails' size was variable, and infected snails were identified independently of rainfall. Conclusions These results provide evidence of anthropogenic and climate interference in an urban focus of schistosomiasis in the Aracaju metropolitan area.