Potential infectivity of blood from HBsAG asymptomatic carriers due to the presence of HBV-DNA and comparison with other markers of hbv infection

Serum samples from 356 HBsAg positive asymptomatic carriers, which were titrated by reverse passive hemagglutination, were analysed for the presence of HBV-DNA, HBsAg and IgM anti-HBc. The samples were divided in three classes, according to the titers of HBsAg and IgM anti-HBc and the distribution of HBV-DNA and HBsAg among these classes was studied. In the high titer class of HBsAg, 65% of samples have one or both markers against only 19% in the low titer class. From the total of 356 samples, 121 gave positive results for IgM anti-HBc (33.9%). From these, 38.9% of HBV-DNA and 47.9% of HBeAg were observed, whereas in samples with absence of IgM anti-HBc, 18.3% and 16.6% were respectively found. A higher frequency of agreement between all these markers was found in the class of high titers of HBsAg; however, HBV-DNA was detected in the low titer class of HBsAg and little or no IgM anti-HBc, showing potential blood infectivity even in HBsAg positive borderline samples.

Comparative studies of Yersinia pestis outer membrane isolation techniques and their potential use in plague epidemiology

In the present study three techniques for obtaining outer membrane enriched fractions from Yersinia pestis were evaluated. The techniques analysed were: differential solubilization of the cytoplasmic membrane with Sarkosyl or Triton X-100, and centrifugation in sucrose density gradients. The sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of outer membrane isolated by the different methods resulted in similar protein patterns. The measurement of NADH-dehydrogenase and succinate dehydrogenase (inner membrane enzymes) indicated that the outer membrane preparations obtained by the three methods were pure enough for analytical studies. In addition, preliminary evidences on the potential use of outer membrane proteins for the identification of geographic variants of Y. pestis wild isolates are presented.

Potential dementia biomarkers based on the time-varying microstructure of sleep EEG spindles

Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France August 23-26, 2007

Commercial squids: Characterization, assessment of potential health benefits/risks and discrimination based on mineral, lipid and vitamin E concentrations

The most consumed squid species worldwide were characterized regarding their concentrations of minerals, fatty acids, cholesterol and vitamin E. Interspecific comparisons were assessed among species and geographical origin. The health benefits derived from squid consumption were assessed based on daily minerals intake and on nutritional lipid quality indexes. Squids contribute significantly to daily intake of several macro (Na, K, Mg and P) and micronutrients (Cu, Zn and Ni). Despite their low fat concentration, they are rich in long-chain omega-3 fatty acids, particularly docosahexaenoic (DHA) and eicosapentanoic (EPA) acids, with highly favorable ω-3/ω-6 ratios (from 5.7 to 17.7), reducing the significance of their high cholesterol concentration (140–549 mg/100 g ww). Assessment of potential health risks based on minerals intake, non-carcinogenic and carcinogenic risks indicated that Loligo gahi (from Atlantic Ocean), Loligo opalescens (from Pacific Ocean) and Loligo duvaucelii (from Indic Ocean) should be eaten with moderation due to the high concentrations of Cu and/or Cd. Canonical discriminant analysis identified the major fatty acids (C14:0, C18:0, C18:1, C18:3ω-3, C20:4ω-6 and C22:5ω-6), P, K, Cu and vitamin E as chemical discriminators for the selected species. These elements and compounds exhibited the potential to prove authenticity of the commercially relevant squid species.

Riesz potential versus fractional Laplacian

This paper starts by introducing the Grünwald–Letnikov derivative, the Riesz potential and the problem of generalizing the Laplacian. Based on these ideas, the generalizations of the Laplacian for 1D and 2D cases are studied. It is presented as a fractional version of the Cauchy–Riemann conditions and, finally, it is discussed with the n-dimensional Laplacian.

Chicken as potential contamination source of Campylocacter lari in Iquitos, Peru

In order to know the importance of chicken as natural reservoir of Campylobacter lari in Iquitos, Peru; samples were obtained by cloacal swabs from 200 chickens and immediately placed into a semisolid enrichment medium; these were streaked on modified Skirrow Agar. The organism was isolated from 21 (10.5%) samples, corresponding 58.8% to biovar I and 41.2% to biovar II (Lior scheme). The results provide evidence that chicken appear to be prominent reservoirs of Campylobacter lari in Iquitos.

Mycobacterium avium complex (MAC): an unusual potential pathogen in cerebrospinal fluid of AIDS patients

Mycobacterium avium complex (MAC) is frequently isolated from patients with late complications of Acquired Immunodeficiency Syndrome (AIDS), especially in North America and Europe. However, its isolation from the central nervous system (CNS) has been seldom reported in these countries. MAC infections in AIDS patients in African and Latin American countries are believed to be uncommon. We report the isolation of MAC from cerebrospinal fluid (CSF) of 11 AIDS patients out of 1723 (0.63%) seen at "Centro de Referência e Treinamento - AIDS", São Paulo and discuss the significance of its isolation.

Estudo eletroquímico do dano oxidativo promovido por RNOS e PAH e o efeito protetor de antioxidantes no ADN

No dia-a-dia, os organismos vivos estão sujeitos a vários tipos de agressões de origem endógena e exógena. A produção endógena exagerada de agentes oxidantes que ocorre nos processos metabólicos dos seres vivos está intimamente associada ao aparecimento e desenvolvimento de várias patologias. Por outro lado, e devido às atividades antropogénicas, muitos agentes oxidantes de origem ambiental e alimentar entram por via exógena no organismo dos seres vivos provocando igualmente danos a nível celular. De modo a protegerem-se dos efeitos pejorativos provocados por estes compostos, os organismos vivos desenvolveram mecanismos complexos de defesa antioxidante. Este trabalho consistiu no estudo eletroquímico do dano oxidativo induzido por agentes oxidantes (PAH (hidrocarbonetos aromáticos policíclicos), H2O2, NO• e HClO) e do efeito protetor, ao dano oxidativo, promovido por antioxidantes no material baseado no ADN recorrendo à utilização de um biossensor de bases púricas, adenina-EPC (elétrodo pasta de carbono) e dA20-EPC, utilizando a voltametria de onda quadrada (VOQ) como técnica de deteção. A aplicação da eletroquímica apresenta várias vantagens para a quantificação da capacidade antioxidante total (CAT) pois, permite a redução da quantidade de reagentes e amostra em análise, elimina a etapa de remoção de cor (a cor é um interferente nos métodos óticos) e não requer equipamentos dispendiosos. Foram seguidas diferentes abordagens para a construção dos biossensores. A primeira consistiu na construção de um adenina-EPC em três etapas: i) condicionamento do EPC, ii) eletrodeposição da adenina no EPC e iii) leitura do sinal eletroquímico. Assim, foram otimizados diversos parâmetros: concentração de adenina (150,0 mg/L), potencial de condicionamento (Ec) (+ 1,80 V), potencial de deposição (Ed) (+ 0,40 V), tempo de condicionamento (tc) (180 s) e tempo de deposição (td) (240 s). Foi aplicado o adenina-EPC no estudo do dano oxidativo provocado por PAH (benzo (g,h,i) perileno) e constatou-se que era necessário transformar o benzo (g,h,i) perileno num radical para se possível observar danos oxidativos induzidos no biossensor. A nova estratégia consistiu na construção de um dA20-EPC, através da adsorção física de uma gota de dA20 na superfície do EPC, com posterior secagem e leitura do sinal eletroquímico. Neste procedimento foi otimizada a concentração de dA20 (100,0 mg/L). O dano oxidativo provocado pelo H2O2, NO• e HClO foi estudado sobre o dA20-EPC e verificou-se que os três agentes oxidantes induziam dano oxidativo no dA20-EPC. Confirmou-se a capacidade do ácido ascórbico (AA) em proteger o dA20-EPC do dano oxidativo induzido por H2O2 e NO•. O biossensor desenvolvido (dA20-EPC) foi aplicado na avaliação da CAT de diferentes amostras reais (café, sumo de laranja e água aromatizada de laranja) usando-se como agentes oxidantes o H2O2 e NO•. Todas as amostras analisadas apresentaram ter capacidade antioxidante. Quando se utilizou o dA20-EPC na presença de H2O2, verificou-se que as amostras de café apresentam valores mais elevados de CAT (1130-1488 mg AAE/L) do que as amostras de bebidas (110 mg AAE/L em água aromatizada e 775 mg AAE/L em sumo). Os valores de CAT obtidos para amostras de sumo e água aromatizada na presença de NO• indicam que a amostra de sumo possui maior teor de CAT (871 mg AAE/L) conforme era esperado, do que a amostra de água aromatizada (172 mg AAE/L). Na presença de HClO, o valor de CAT mais elevado pertence a uma amostra de sumo (513 mg AAE/L) mas, o valor de CAT da amostra de sumo natural é muito mais baixa do que o esperado (17 mg AAE/L). Foram estudados outros antioxidantes para além do AA (ácido cumárico, ácido gálico e ácido cafeico), e constatou-se que cada um deles promove proteção ao dA20-EPC na presença de cada um dos diferentes contaminantes (H2O2, NO• e HClO).

Rapid Characterization of S. mansoni Expression Library Clones of Potential Interest

A S. mansoni adult worm cDNA expression library was screened with sera from baboons in a early phase after infection. The clones that were positive with the early infection sera were examined for reactivity with pre-infection sera and heterologous infection sera. In order to discriminate a positive antibody reaction from the reactivity due to residual anti-E. coli antibodies, an unrelated cDNA clone was plated with the positive clone. The unrelated clone provided the negative background and the contrast necessary to discern a positive antibody reaction. In this way, we were able to eliminate selected clones that were positive with the pre-infection sera or heterologous infection sera. This characterization of the expression library clones enabled us to quickly target only clones with the desired pattern of antibody reactivity for sequencing, subcloning, and expressing

Massive shift in the pneumococcal nasopharyngeal flora after the 7-valent conjugate vaccine: epidemiological studies and testing pathogenic potential in animal models

Dissertation presented to obtain the PhD degree in Biology/Molecular Biology by Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica

Picocyanobacteria From a Clade Of Marine Cyanobium Revealed Bioactive Potential Against Microalgae, Bacteria, And Marine

The production of bioactive compounds either toxic or with pharmacological applications by cyanobacteria is well established. However, picoplanktonic forms within this group of organisms have rarely been studied in this context. In this study, the toxicological potential of picocyanobacteria from a clade of marine Cyanobium strains isolated from the Portuguese coast was examined using different biological models. First, strains were identified by applying morphological and molecular approaches and cultured under lab conditions. A crude extract and three fractions reflecting a preliminary segregation of lipophilic metabolites were tested for toxicity with the marine microalga Nannochloropsis sp., the bacteria Pseudomonas sp., the brine shrimp Artemia salina, and fertilized eggs of the sea urchin Paracentrotus lividus. No significant apparent adverse effects were noted against Artemia salina. However, significant adverse effects were found in all other assays, with an inhibition of Nannochloropsis sp. and Pseudomonas sp. growth and marked reduction in Paracentrotus lividus larvae length. The results obtained indicated that Cyanobium genus may serve as a potential source of interesting bioactive compounds and emphasize the importance of also studying smaller picoplanktonic fractions of marine cyanobacteria.

PCR with Paracoccidioides brasiliensis specific primers: potential use in ecological studies

The precise microenvironment of Paracoccidioides brasiliensis has not yet been discovered perhaps because the methods used are not sensitive enough. We applied to this purpose the polymerase chain reaction (PCR) using three sets of specific primers corresponding to two P. brasiliensis genes. This fungus as well as several other fungi, were grown and their DNA obtained by mechanical disruption and a phenol chloroform isoamylalcohol-based purification method. The DNA served for a PCR reaction that employed specific primers from two P. brasiliensis genes that codify for antigenic proteins, namely, the 27 kDa and the 43 kDa. The lowest detection range for the 27 kDa gene was 3 pg. The amplification for both genes was positive only with DNA from P. brasiliensis; additionally, the mRNA for the 27 kDa gene was present only in P. brasiliensis, as indicated by the Northern analysis. The standardization of PCR technology permitted the amplification of P. brasiliensis DNA in artificially contaminated soils and in tissues of armadillos naturally infected with the fungus. These results indicate that PCR technology could play an important role in the search for P. brasiliensis’ habitat and could also be used in other ecological studies.