Study of behavioural and neural bases of visuo-spatial working memory with an fMRI paradigm based on an n-back task

The goal of this study was to propose a new functional magnetic resonance imaging (fMRI) paradigm using a language-free adaptation of a 2-back working memory task to avoid cultural and educational bias. We additionally provide an index of the validity of the proposed paradigm and test whether the experimental task discriminates the behavioural performances of healthy participants from those of individuals with working memory deficits. Ten healthy participants and nine patients presenting working memory (WM) deficits due to acquired brain injury (ABI) performed the developed task. To inspect whether the paradigm activates brain areas typically involved in visual working memory (VWM), brain activation of the healthy participants was assessed with fMRIs. To examine the task's capacity to discriminate behavioural data, performances of the healthy participants in the task were compared with those of ABI patients. Data were analysed with GLM-based random effects procedures and t-tests. We found an increase of the BOLD signal in the specialized areas of VWM. Concerning behavioural performances, healthy participants showed the predicted pattern of more hits, less omissions and a tendency for fewer false alarms, more self-corrected responses, and faster reaction times, when compared with subjects presenting WM impairments. The results suggest that this task activates brain areas involved in VWM and discriminates behavioural performances of clinical and non-clinical groups. It can thus be used as a research methodology for behavioural and neuroimaging studies of VWM in block-design paradigms.

Analysis of proteins from membrane and soluble fractions of Giardia duodenalis trophozoites of two Brazilian axenic strains

In the present study, we have analyzed by sodium docecyl sulphate - polyacrilamide gel electrophoresis (SDS-PAGE), immunoblotting and Concanavalin A blotting (Con A blotting) proteins of membrane fractions and soluble fractions obtained from Giardia duodenalis trophozoites of two axenic strains isolated in Brazil from a symptomatic (BTU-11) and an asymptomatic patient (BTU-10), as compared to the reference strain Portland 1. Both Brazilian strains showed a complex and homogeneous electrophoretic pattern of proteins, but some differences could be observed. Several glycoproteins were detected, particularly the proteins of 81, 72, 59 kDa and the protein of 62 kDa in the membrane proteins and cytosol, respectively. Many antigenic components were revealed by anti-Giardia rabbit IgG antibodies in the immunoblotting analysis. Among these components, the membrane protein of 32 kDa and the cytosol protein of 30 kDa could be related to giardin, as previously demonstrated.

Analysis of genetic relatedness between populations of Aedes aegypti from different geographic regions of São Paulo state, Brazil

RAPD markers have been used for the analysis of genetic differentiation of Aedes aegypti, because they allow the study of genetic relationships among populations. The aim of this study was to identify populations in different geographic regions of the São Paulo State in order to understand the infestation pattern of A. aegypti. The dendrogram constructed with the combined data set of the RAPD patterns showed that the mosquitoes were segregated into two major clusters. Mosquitoes from the Western region of the São Paulo State constituted one cluster and the other was composed of mosquitoes from a laboratory strain and from a coastal city, where the largest Latin American port is located. These data are in agreement with the report on the infestation in the São Paulo State. The genetic proximity was greater between mosquitoes whose geographic origin was closer. However, mosquitoes from the coastal city were genetically closer to laboratory-reared mosquitoes than to field-collected mosquitoes from the São Paulo State. The origin of the infestation in this place remains unclear, but certainly it is related to mosquitoes of origins different from those that infested the West and North region of the State in the 80's.

Molecular and seroepidemiologic studies of Enterovirus 71 infection in the State of Pará, Brazil

In many countries, the Enterovirus 71 (EV-71) Picornaviridae family is associated to hand, foot and mouth disease in addition to acute neurological diseases while in Brazil these viruses are more closely associated to the latter group. The aim of this research was to use the first EV-71 isolate of the Northern region of Brazil in molecular and seroepidemiologic studies. Two (2.2%) out of 88 stool samples (44 cases of AFP), collected from January 1998 to December 2000 were positive for EV-71 isolation (73442/PA/99). Nucleotide sequence of the gen that codifies the VP1 protein showed that isolate 73442/PA/99 was similar to the EV-71 strains belonging to genotype B - more closely identified with EV-71 from North America. Neutralization test with 389 sera samples collected from January 1998 to November 2001, from individuals ranging from 0 to 15 years of age living in the city of Belém, State of Pará showed the following results in relation to isolate 73442/PA/99 and prototype BrCr: a total of 207 individuals (53.2%) had neutralization antibodies to both viruses, 167 (42.9%) had no antibodies and 15 showed the presence of neutralizing antibodies to one of the two viruses. Only 20.2% of the children aged 0 to 3 had neutralizing antibodies to EV-71, indicating that these children were more susceptible to the infection. Both the seroprevalence study and VP1 sequencing were important to demonstrate the spread and the molecular pattern of the EV-71 circulating in the Northern Region of Brazil.

Antifungal susceptibilities of clinical and environmental isolates of Cryptococcus neoformans in goiânia city, Goiás, Brasil

We evaluated the antifungal activities of amphotericin B, fluconazole, itraconazole and voriconazole in 70 Cryptococcus neoformans strains obtained from cerebrospinal fluid from AIDS patients and 40 C. neoformans strains isolated from the environment. Four clinical isolates were identified as C. neoformans var. gattii. The susceptibility test was done using a broth microdilution method according to NCCLS M27-A2. Range minimal inhibitory concentrations (MICs) for C. neoformans clinical isolates were 0.06-1.0 µg/mL for amphotericin B, 0.125-8 µg/mL for fluconazole, 0.03-0.5 µg/mL for itraconazole and 0.03-0.25 µg/mL for voriconazole. C. neoformans environmental isolates showed range MICs 0.015-0.125 µg/mL, 0.25-2.0 µg/mL, 0.007-0.125 µg/mL and 0.03-0.25 µg/mL for amphotericin B, fluconazole, itraconazole and voriconazole respectively. The MICs results obtained from clinical and environmental isolates showed similar pattern of susceptibility and no resistance has been found in our isolates.

High prevalence of malaria infection in Amazonas state, Venezuela

This study was carried out to determine the incidence of malaria in an endemic region of Amazonas State, Venezuela. For this, 200 random samples were collected from symptomatic and asymptomatic individuals from San Fernando de Atabapo and Santa Barbara. Epidemiological factors were related to malaria infection, which was diagnosed by microscopy observation and amplification of the 18S rDNA sequence by PCR. Malaria prevalence in these populations was 28.5%, whilst P. vivax and P. falciparum prevalences were 12 and 17%, respectively. No infection by P. malariae was found. A mixed infection was found on an asymptomatic individual. Prevalence patterns differed between age groups depending on the Plasmodium species. We found that 34.8% of the P. vivax and 15.2% of the P. falciparum infections were asymptomatic. The use of nets was helpful to prevent P. vivax infection, but did not protect against P. falciparum infection. The results suggest the presence of more than one mosquito vector in the area, displaying a differential pattern of infection for each Plasmodium species. There appear to be risk factors associated with malaria infections in some individuals. The population based approach and PCR diagnosis improved the accuracy of the statistical analysis in the study.

Inflammatory and Cardiometabolic Risk on Obesity: Role of Environmental Xenoestrogens

Context: Some chemicals used in consumer products or manufacturing (eg, plastics, pesticides) have estrogenic activities; these xenoestrogens (XEs) may affect immune responses and have recently emerged as a new risk factors for obesity and cardiovascular disease. However, the extent and impact on health of chronic exposure of the general population to XEs are still unknown. Objective: The objective of the study was to investigate the levels of XEs in plasma and adipose tissue (AT) depots in a sample of pre- and postmenopausal obese women undergoing bariatric surgery and their cardiometabolic impact in an obese state. Design and Participants: We evaluated XE levels in plasma and visceral and subcutaneous AT samples of Portuguese obese (body mass index ≥ 35 kg/m2) women undergoing bariatric surgery. Association with metabolic parameters and 10-year cardiovascular disease risk was assessed, according to menopausal status (73 pre- and 48 postmenopausal). Levels of XEs were determined by gas chromatography with electron-capture detection. Anthropometric and biochemical data were collected prior to surgery. Adipocyte size was determined on tissue sections obtained during surgery. Results: Our data show that XEs are pervasive in this obese population. Distribution of individual and concentration of total XEs differed between plasma, visceral AT, and subcutaneous AT, and the pattern of accumulation was different between pre- and postmenopausal women. Significant associations between XE levels and metabolic and inflammatory parameters were found. In premenopausal women, XEs in plasma seem to be a predictor of 10-year cardiovascular disease risk. Conclusions: Our findings point toward a different distribution of XE between plasma and AT in pre- and postmenopausal women, and reveal the association between XEs on the development of metabolic abnormalities in obese premenopausal women

Slipped Capital Femoral Epiphysis. A Report of 4 Cases Occurring in One Family

We describe slipped capital femoral epiphysis in 4 members of a black, obese family, who were all first-degree relatives. The aetiology of slipped capital femoral epiphysis is unknown, although it is thought to be multifactorial. Genetic predisposition and environmental factors have been associated with the condition. A familial incidence with at least two cases in the same family has been reported. In epidemiological studies, this incidence ranges from 3% to 35%. Our cases were investigated in an attempt to find a possible aetiological genetic factor. A genetic predisposition with an autosomal dominant pattern of transmission is suggested, although environmental variables must be considered as provocative factors.

Effectiveness of the Brazilian influenza vaccination policy, a systematic review

Since 1999, Brazil has undertaken annual influenza vaccine campaigns, free of charge, targeting the elderly population, health professionals, and immune-deficient patients. We conducted a systematic review of literature in order to evaluate the effectiveness of the initiative. We used the keywords influenza, vaccine, Brazil and effectiveness to search the main databases. Thirty-one studies matched our inclusion and exclusion criteria. Influenza vaccine coverage among the elderly is high, though not as high as suggested by the official figures. Estimates on effectiveness are scarce. The majority come from ecological studies that show a modest reduction in mortality and hospital admissions due to influenza-related causes. Such reduction is not evident in the North and Northeastern states of Brazil, a finding that is probably related to the different seasonal pattern of influenza in equatorial and tropical regions. Brazilian epidemiologists still owe society better-designed studies addressing the effectiveness of influenza vaccine campaigns.

Ankylosing spondylitis: genomic and functional characterization of candidate genes and their repercussion in clinical practice

RESUMO: Introdução: A espondilite anquilosante (EA) é uma doença inflamatória crónica caracterizada pela inflamação das articulações sacroilíacas e da coluna. A anquilose progressiva motiva uma deterioração gradual da função física e da qualidade de vida. O diagnóstico e o tratamento precoces podem contribuir para um melhor prognóstico. Neste contexto, a identificação de biomarcadores, assume-se como sendo muito útil para a prática clínica e representa hoje um grande desafio para a comunidade científica. Objetivos: Este estudo teve como objetivos: 1 - caracterizar a EA em Portugal; 2 - investigar possíveis associações entre genes, MHC e não-MHC, com a suscetibilidade e as características fenotípicas da EA; 3 - identificar genes candidatos associados a EA através da tecnologia de microarray. Material e Métodos: Foram recrutados doentes com EA, de acordo com os critérios modificados de Nova Iorque, nas consultas de Reumatologia dos diferentes hospitais participantes. Colecionaram-se dados demográficos, clínicos e radiológicos e colhidas amostras de sangue periférico. Selecionaram-se de forma aleatória, doentes HLA-B27 positivos, os quais foram tipados em termos de HLA classe I e II por PCR-rSSOP. Os haplótipos HLA estendidos foram estimados pelo algoritmo Expectation Maximization com recurso ao software Arlequin v3.11. As variantes alélicas dos genes IL23R, ERAP1 e ANKH foram estudadas através de ensaios de discriminação alélica TaqMan. A análise de associação foi realizada utilizando testes da Cochrane-Armitage e de regressão linear, tal como implementado pelo PLINK, para variáveis qualitativas e quantitativas, respetivamente. O estudo de expressão génica foi realizado por Illumina HT-12 Whole-Genome Expression BeadChips. Os genes candidatos foram validados usando qPCR-based TaqMan Low Density Arrays (TLDAs). Resultados: Foram incluídos 369 doentes (62,3% do sexo masculino, com idade média de 45,4 ± 13,2 anos, duração média da doença de 11,4 ± 10,5 anos). No momento da avaliação, 49,9% tinham doença axial, 2,4% periférica, 40,9% mista e 7,1% entesopática. A uveíte anterior aguda (33,6%) foi a manifestação extra-articular mais comum. Foram positivos para o HLA-B27, 80,3% dos doentes. Os haplótipo A*02/B*27/Cw*02/DRB1*01/DQB1*05 parece conferir suscetibilidade para a EA, e o A*02/B*27/Cw*01/DRB1*08/DQB1*04 parece conferir proteção em termos de atividade, repercussão funcional e radiológica da doença. Três variantes (2 para IL23R e 1 para ERAP1) mostraram significativa associação com a doença, confirmando a associação destes genes com a EA na população Portuguesa. O mesmo não se verificou com as variantes estudadas do ANKH. Não se verificou associação entre as variantes génicas não-MHC e as manifestações clínicas da EA. Foi identificado um perfil de expressão génica para a EA, tendo sido validados catorze genes - alguns têm um papel bem documentado em termos de inflamação, outros no metabolismo da cartilagem e do osso. Conclusões: Foi estabelecido um perfil demográfico e clínico dos doentes com EA em Portugal. A identificação de variantes génicas e de um perfil de expressão contribuem para uma melhor compreensão da sua fisiopatologia e podem ser úteis para estabelecer modelos com relevância em termos de diagnóstico, prognóstico e orientação terapêutica dos doentes. -----------ABSTRACT: Background: Ankylosing Spondylitis (AS) is a chronic inflammatory disorder characterized by inflammation in the spine and sacroiliac joints leading to progressive joint ankylosis and in progressive deterioration of physical function and quality of life. An early diagnosis and early therapy may contribute to a better prognosis. The identification of biomarkers would be helpful and represents a great challenge for the scientific community. Objectives: The present study had the following aims: 1- to characterize the pattern of AS in Portuguese patients; 2- to investigate MHC and non-MHC gene associations with susceptibility and phenotypic features of AS and; 3- to identify candidate genes associated with AS by means of whole-genome microarray. Material and Methods: AS was defined in accordance to the modified New York criteria and AS cases were recruited from hospital outcares patient clinics. Demographic and clinical data were recorded and blood samples collected. A random group of HLA-B27 positive patients and controls were selected and typed for HLA class I and II by PCR-rSSOP. The extended HLA haplotypes were estimated by Expectation Maximization Algorithm using Arlequin v3.11 software. Genotyping of IL23R, ERAP1 and ANKH allelic variants was carried out with TaqMan allelic discrimination assays. Association analysis was performed using the Cochrane-Armitage and linear regression tests as implemented in PLINK, for dichotomous and quantitative variables, respectively. Gene expression profile was carried out using Illumina HT-12 Whole-Genome Expression BeadChips and candidate genes were validated using qPCR-based TaqMan Low Density Arrays (TLDAs). Results: A total of 369 patients (62.3% male; mean age 45.4±13.2 years; mean disease duration 11.4±10.5 years), were included. Regarding clinical disease pattern, at the time of assessment, 49.9% had axial disease, 2.4% peripheral disease, 40.9% mixed disease and 7.1% isolated enthesopathic disease. Acute anterior uveitis (33.6%) was the most common extra-articular manifestation. 80.3% of AS patients were HLA-B27 positive. The haplotype A*02/B*27/Cw*02/DRB1*01/DQB1*05 seems to confer susceptibility to AS, whereas A*02/B*27/Cw*01/DRB1*08/DQB1*04 seems to provide protection in terms of disease activity, functional and radiological repercussion. Three markers (two for IL23R and one for ERAP1) showed significant single-locus disease associations. Association of these genes with AS in the Portuguese population was confirmed, whereas ANKH markers studied did not show an association with AS. No association was seen between non-MHC genes and clinical manifestations of AS. A gene expression signature for AS was established; among the fourteen validated genes, a number of them have a well-documented inflammatory role or in modulation of cartilage and bone metabolism. Conclusions: A demographic and clinical profile of patients with AS in Portugal was established. Identification of genetic variants of target genes as well as gene expression signatures could provide a better understanding of AS pathophysiology and could be useful to establish models with relevance in terms of susceptibility, prognosis, and potential therapeutic guidance.

Microbiological quality of drinking rainwater in the inland region of Pajeú, Pernambuco, Northeast Brazil

Despite all efforts to store and reduce its consumption, water is becoming less inexhaustible and its quality is falling faster. Considering that water is essential to animal life, it is necessary to adopt measures to ensure its sanitary conditions in order to be fit for consumption. The aim of this study was to analyze the microbiological quality of drinking rainwater used by rural communities of Tuparetama, a small town located in Northeast Brazil. The study covered seven rural communities, totaling 66 households. In each household two samples were collected, one from a tank and the other from a clay pot located inside the home, resulting in 132 samples (tank plus clay pot). Approximately 90% of samples were below the standard recommended by the current legislation, being considered unfit for human consumption. Part of this high microbiological contamination of drinking rainwater could be related to the lack of sanitary education and of an adequate sewerage sanitation system.

Isolation of yellow fever virus (YFV) from naturally infectied Haemagogus (Conopostegus) leucocelaenus (diptera, cukicudae) in São Paulo State, Brazil, 2009

After detecting the death of Howlers monkeys (genus Alouatta) and isolation of yellow fever virus (YFV) in Buri county, São Paulo, Brazil, an entomological research study in the field was started. A YFV strain was isolated from newborn Swiss mice and cultured cells of Aedes albopictus - C6/36, from a pool of six Haemagogus (Conopostegus) leucocelaenus (Hg. leucocelaenus) mosquitoes (Dyar & Shannon) collected at the study site. Virus RNA fragment was amplified by RT-PCR and sequenced. The MCC Tree generated showed that the isolated strain is related to the South American I genotype, in a monophyletic clade containing isolates from recent 2008-2010 epidemics and epizootics in Brazil. Statistical analysis commonly used were calculated to characterize the sample in relation to diversity and dominance and indicated a pattern of dominance of one or a few species. Hg. leucocelaenus was found infected in Rio Grande do Sul State as well. In São Paulo State, this is the first detection of YFV in Hg. leucocelaenus.

Stochastic simulation of the morphology of fluvial sand channels reservoirs

Dissertação para obtenção do Grau de Mestre em Engenharia Geológica (Georrecursos)

Expression of TLR2 and TLR4 in lesions of patients with tegumentary american leishmaniasis

OBJECTIVES: The aim of this study was to describe the pattern of expression of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in skin biopsies of patients with American tegumentary leishmaniasis (ATL) caused by Leishmania braziliensis. METHODS: This prospective study evaluated 12 patients with ATL caused by Leishmania braziliensis confirmed by polymerase chain reaction. Immunohistochemistry was performed to determine the expression of TLR2 and TLR4. The number of NK cells, dendritic cells and macrophages in the tissue were calculated. The cytokine expression was determined using the anti-TNF-α, anti-IFN-Γ, anti-IL-1 and anti-IL-6. Double immunostaining reactions were used to determine the cell expressing TLR2 and TLR4. RESULTS: The numbers of cells expressing TLR2 and TLR4 were 145.48 ± 82.46 cell/mm² and 3.26 ± 4.11 cell/mm² respectively (p < 0.05). There was no correlation of TLR2 and TLR4 with the amount of cytokines and the number of NK cells, dendritic cells or macrophages. The double immunostaining revealed that TLR2 was expressed by macrophages. CONCLUSION: In human cutaneous leishmaniasis caused by Leishmania braziliensis, TLR2 is the most common TLR expressed during active disease, mainly by macrophages although without correlation with the amount of cytokines and number of cells.

FREQUENCY, URINALYSIS AND SUSCEPTIBILITY PROFILE OF PATHOGENS CAUSING URINARY TRACT INFECTIONS IN ENUGU STATE, SOUTHEAST NIGERIA

Objective: This study was designed to determine the frequency and causative agent(s) of urinary tract infections (UTIs) in individuals with symptoms of urinary tract infections in Enugu State of Southeast Nigeria, and to determine the antibiotic susceptibility pattern of microbial agents isolated from urine culture.Methods: The study involved 211 individuals (149 females and 62 males) clinically suspected for UTI. Urine samples were collected by the mid-stream ‘clean catch’ method and tested using standard procedures. Antibiotic susceptibility of the isolated pathogens was tested using the Kirby-Bauer technique according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.Results: Microscopy of centrifuged urine samples showed 16 patients had pyuria while 54 had pus cells. Calcium oxalate crystals were found in 14 samples. Urinalysis performed with urine samples showed 17 had protein; seven were nitrite positive and three had moderate to high glucose concentration. Fifty-four urine samples (36.2%) from females and 12 (19.4%) from males showed significant growth upon culture. Gram stain and biochemical tests identified nine different organisms with Escherichia coli as the most common isolated species. Forty three randomly selected strains were further tested for their susceptibility against a panel of antibiotics. Thirty isolates (81.08%) were resistant to four or more antibiotics with the highest resistance shown by E. coli (76.67%). All the Gram- negative isolates were resistant to Ampicilox, Cefuroxime and Amoxicillin.Conclusion: Urinary tract infections were found more in females in the area under study. As found in other studies, E. coli was the most predominant isolate, although other organisms seem to be on the increase.