Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam

BACKGROUND: Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. METHODS: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed : Polyα, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. RESULTS: The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country. CONCLUSION: Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages

Detec??o autom?tica de exsudatos e microaneurismas em imagens de retinopatia diab?tica utilizando o algoritmo bioinspirado na col?nia artificial de abelhas e processamento digital de imagens

O diagn?stico da retinopatia diab?tica, em imagens do fundo do olho, impulsionou o desenvolvimento de algoritmos de processamento que fossem capazes de identificar e classificar patologias automaticamente. As t?cnicas de processamento digital de imagens, aplicadas a medicina, facilitam a visualiza??o e identifica??o de patologias a partir de minimiza??o de artefatos indesej?veis nas imagens. O objetivo do presente trabalho consiste em implementar pelo m?todo baseado na col?nia artificial de abelhas (Artificial Bee Colony - ABC), para adetec??o de exsudatos, e o uso de t?cnicas de processamento digital de imagens para facilitar nos processos de detec??o e classifica??o das microaneurismas. Como sinais de entrada para os algoritmos, foram utilizadas as imagens do banco de dados da Diaretdb1. T?cnicas de pr?-processamento foram utilizadas para realizar a exclus?o do disco ?ptico (proje??o luminosa decorrente dos exames de fundoscopia), e uma m?scara foi proposta para encontrar nas imagens a patologia, com base na forma e tamanho da mesma. Para a avalia??o dos algoritmos desenvolvidos foram utilizadas as taxas de sensibilidade, especificidade e acur?cia das imagens. Na detec??o dos exsudatos os valores coletados ap?s o pos-processamento foram 85% de sensibilidade, 92% de especificidade e 96% de acur?cia. Na detec??o e classifica ??o das microaneurismas, os testes retornaram 75% de sensibilidade, 99% de especificidade e 98% de acur?cia. Conforme as imagens resultantes dos processos de detec??o, foram identificados 52 pacientes com a presen?a de exsudatos em compara??o com o banco de dados que diagnosticaram 48 pacientes com a doen?a. O algoritmo de classifica??o detectou a evid?ncia de microaneurismas em 75 pacientes e o banco de dados diagnosticou a patologia em 71

Passado, presente e futuro da Engenharia Biológica

Textos e apresentações da sessão "Passado, Presente e Futuro da Engenharia Biológica", no âmbito do programa comemorativo dos 20 anos da Licenciatura em Engenharia Biológica da Universidade do Minho

Intercentre reproducibility of cardiac apparent diffusion coefficient and fractional anisotropy in healthy volunteers

BACKGROUND: Diffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in-vivo diffusion measures using the sequence. METHODS AND RESULTS: A stimulated-echo, cardiac-gated DT-CMR sequence with a reduced-field-of-view, single-shot EPI readout was used at two centres with 3 T MRI scanners. Four alkane phantoms with known diffusivities were scanned at a single centre using a stimulated echo sequence and a spin-echo Stejskal-Tanner diffusion sequence. The median (maximum, minimum) difference between the DT-CMR sequence and Stejskal-Tanner sequence was 0.01 (0.04, 0.0006) × 10(-3) mm(2)/s (2%), and between the DT-CMR sequence and literature diffusivities was 0.02 (0.05, 0.006) × 10(-3) mm(2)/s (4%). The same ten healthy volunteers were scanned using the DT-CMR sequence at the two centres less than seven days apart. Average ADC and FA were calculated in a single mid-ventricular, short axis slice. Intercentre differences were tested for statistical significance at the p < 0.05 level using paired t-tests. The mean ADC ± standard deviation for all subjects averaged over both centres was 1.10 ± 0.06 × 10(-3) mm(2)/s in systole and 1.20 ± 0.09 × 10(-3) mm(2)/s in diastole; FA was 0.41 ± 0.04 in systole and 0.54 ± 0.03 in diastole. With similarly-drawn regions-of-interest, systolic ADC (difference 0.05 × 10(-3) mm(2)/s), systolic FA (difference 0.003) and diastolic FA (difference 0.01) were not statistically significantly different between centres (p > 0.05), and only the diastolic ADC showed a statistically significant, but numerically small, difference of 0.07 × 10(-3) mm(2)/s (p = 0.047). The intercentre, intrasubject coefficients of variance were: systolic ADC 7%, FA 6%; diastolic ADC 7%, FA 3%. CONCLUSIONS: This is the first study to demonstrate the accuracy of a stimulated-echo DT-CMR sequence in phantoms, and demonstrates the feasibility of obtaining reproducible ADC and FA in healthy volunteers at separate centres with well-matched sequences and processing

Pressure effects on the structural and superconducting transitions in La₃Co₄Sn₁₃

La3Co4Sn13 is a superconducting material with transition temperature at Tc = 2.70 K, which presents a superlattice structural transition at T ∗ ≃ 150 K, a common feature for this class of compounds. However, for this material, it is not clear that at T ∗ the lattice distortions arise from a charge density wave (CDW) or from a distinct microscopic origin. Interestingly, it has been suggested in isostructural non-magnetic intermetallic compounds that T ∗ can be suppressed to zero temperature, by combining chemical and external pressure, and a quantum critical point is argued to be observed near these critical doping/pressure. Our study shows that application of pressure on single-crystalline La3Co4Sn13 enhances Tc and decreases T ∗ . We observe thermal hysteresis loops for cooling/heating cycles around T ∗ for P & 0.6 GPa, in electrical resistivity measurements, which are not seen in x-ray diffraction data. The hysteresis in electrical measurements may be due to the pinning of the CDW phase to impurities/defects, while the superlattice structural transition maintains its ambient pressure second-order transition nature under pressure. From our experiments we estimate that T ∗ vanishes at around 5.5 GPa, though no quantum critical behavior is observed up to 2.53 GPa

Characterisation of the bacterial and fungal communities associated with different lesion sizes of Dark Spot Syndrome occurring in the Coral Stephanocoenia intersepta

The number and prevalence of coral diseases/syndromes are increasing worldwide. Dark Spot Syndrome (DSS) afflicts numerous coral species and is widespread throughout the Caribbean, yet there are no known causal agents. In this study we aimed to characterise the microbial communities (bacteria and fungi) associated with DSS lesions affecting the coral Stephanocoenia intersepta using nonculture molecular techniques. Bacterial diversity of healthy tissues (H), those in advance of the lesion interface (apparently healthy AH), and three sizes of disease lesions (small, medium, and large) varied significantly (ANOSIM R = 0.052 p,0.001), apart from the medium and large lesions, which were similar in their community profile. Four bacteria fitted into the pattern expected from potential pathogens; namely absent from H, increasing in abundance within AH, and dominant in the lesions themselves. These included ribotypes related to Corynebacterium (KC190237), Acinetobacter (KC190251), Parvularculaceae (KC19027), and Oscillatoria (KC190271). Furthermore, two Vibrio species, a genus including many proposed coral pathogens, dominated the disease lesion and were absent from H and AH tissues, making them candidates as potential pathogens for DSS. In contrast, other members of bacteria from the same genus, such as V. harveyii were present throughout all sample types, supporting previous studies where potential coral pathogens exist in healthy tissues. Fungal diversity varied significantly as well, however the main difference between diseased and healthy tissues was the dominance of one ribotype, closely related to the plant pathogen, Rhytisma acerinum, a known causal agent of tar spot on tree leaves. As the corals’ symbiotic algae have been shown to turn to a darker pigmented state in DSS (giving rise to the syndromes name), the two most likely pathogens are R. acerinum and the bacterium Oscillatoria, which has been identified as the causal agent of the colouration in Black Band Disease, another widespread coral disease

CD45RA, CD8β, and IFNγ Are Potential Immune Biomarkers of Human Cognitive Function

There is increasing evidence that in humans the adaptive immunological system can influence cognitive functions of the brain. We have undertaken a comprehensive immunological analysis of lymphocyte and monocyte populations as well as of HLA molecules expression in a cohort of elderly volunteers (age range, 64-101) differing in their cognitive status. Hereby, we report on the identification of a novel signature in cognitively impaired elderly characterized by: (1) elevated percentages of CD8+ T effector-memory cells expressing high levels of the CD45RA phosphate receptor (Temra hi); (2) high percentages of CD8+ T cells expressing high levels of the CD8β chain (CD8βhi); (3) augmented production of IFNγ by in vitro activated CD4+ T cells. Noteworthy, CD3+CD8+ Temra hi and CD3+CD8βhi cells were associated with impaired cognition. Cytomegalovirus seroprevalence showed that all volunteers studied but one were CMV positive. Finally, we show that some of these phenotypic and functional features are associated with an increased frequency of the HLA-B8 serotype, which belongs to the ancestral haplotype HLA-A1, Cw7, B8, DR3, DQ2, among cognitively impaired volunteers. To our knowledge, this is the first proof in humans linking the amount of cell surface CD45RA and CD8β chain expressed by CD8+ Temra cells, and the amount of IFNγ produced by in vitro activated CD4+ T cells, with impaired cognitive function in the elderly.info:eu-repo/semantics/publishedVersio

Predictors of goal achievement in an intervention program among Japanese-Brazilians

The aim of this study was to identify baseline factors associated with achieving goals after a 12-month lifestyle intervention program in a Japanese-Brazilian population, using adjusted logistic regression models. In 2005, 321 participants were overweight. The odds [OR (IC95%)] of reaching the goals after 12 months of intervention were directly related to female gender [2.35 (1.34, 4.13)] and older age [1.03 (1.00, 1.06)] and inversely related to baseline morbidity [0.33 (0.14, 0.77)]. Of the 261 sedentary individuals, achieving the goal for physical activity was inversely related to working [0.44 (0.17, 0.95)]. No baseline predictors were found for reaching the goal of fruit and vegetable consumption or saturated fat intake after 12 months. At baseline, women, older individuals, and individuals without diseases or not working showed increased odds of achieving the goals after 12 months of the lifestyle intervention.Identificar fatores da linha de base preditores do alcance das metas do programa de intervenção no estilo de vida após 12 meses em população de nipo-brasileiros, empregando-se modelos de regressão logística ajustados. Em 2005, 321 participantes eram portadores de excesso de peso e houve maior chance [OR (IC95%)] de alcance da meta de perda de peso após 12 meses entre mulheres [2,45 (1,33; 4,13)], indivíduos de maior idade [1,03 (1,00; 1,06)] e menor chance entre portadores de morbidades no início do estudo [0,33 (0,14; 0,77)]. Dos 261 indivíduos sedentários, o alcance da meta de atividades físicas foi inversamente relacionado ao exercício de atividades profissionais [0,40 (0,17; 0,95)]. Não se verificou fatores da linha de base associados ao alcance das metas do consumo de legumes, verduras e frutas e gorduras saturadas da dieta após 12 meses. Indivíduos de maior idade, mulheres, não portadores de morbidades e sem exercício de atividades profissionais na linha de base apresentaram maior chance de alcance das metas após 12 meses de intervenção no estilo de vida.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade de São Paulo Faculdade de Medicina de Ribeirão PretoUniversidade Federal de São Paulo (UNIFESP) Departamento de Medicina PreventivaUniversidade de São Paulo Faculdade de Saúde PúblicaUNIFESP, Depto. de Medicina PreventivaSciEL