Antigenic differences among Leishmania amazonensis isolates and their relationship with distinct clinical forms of the disease

Immunoblot analysis was used to investigate antigenic differences among clinical isolates of Leishmania amazonensis and their role in the etiology of the diseases. Western blots of promastigote homogenates were analyzed with either monoclonal antibodies (MAbs) specific for the L. mexicana complex (M-4, M-6, M-9 and M-11) or polyclonal sera from L. amazonensis infected patients with the various forms of clinical disease. In the case of the MAbs, no significant variation was observed among the strains of L. amazonensis, isolated from cases of cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), diffuse cutaneous leishmaniasis (DCL), visceral leishmaniasis (VL) or post kala-azar dermal leishmaniasis (PKDL), in either the relative morbility (Mr) or the quantitative amount (intensity) of the antigenic determinats. In the case of the sera of the infected patients, the patterns of antigenic reactivity of these strains revealed that, despite showing the presence of shared antigens, differences were observed between some of the antigenic components of the various isolates of L. amazonensis that were recognized by a single serum. Differences were also demonstrated between the antigenic determinants of a single isolate of L. amazonensis that were recognized by the different patient's sera. No apparent association was consistently found, however, between the Mr components identified in these isolates and clinical form of the disease or the geographical area of isolation. In addition, the spectrum of antigens recognized by the sera from patients with the same clinical form were not identical; although in some instances, similar Mr antigens were shared. These results indicate that isolates of L. amazonensis are not antigenically identical (homogeneous) and that the immune responses (antibodies) observed among infected patients are heterogeneous.

Evaluation of some organic compounds on bloodstream forms of Trypanosoma cruzi

Accidental transmission of Chagas' disease to man by blood transfusion is a serious problem in Latin-America. This paper describes the testing of several synthetic, semi-synthetic, and natural compounds for their activity against blood trypomastigotes in vitro at 4-C. The compounds embody several types of chemical structures: benzoquinone, naphthoquinone, anthracenequinone, phenanthrenequinone, imidazole, piperazine, quinoline, xanthene, and simple benzenic and naphthalenic derivates. Some of them are for the first time tested against Trypanosoma cruzi. The toxic effect these compounds on this parasite was done by two quite distinct sets of experiments. In one set, the compounds were added to infected blood as ethanolic solution. In this situation the most active one was a furan-1, 2-naphthoquinone, in the same range as gentian violet, a new fact to be considered in the assessment of structure-activity relationships in this class of compounds. In other set, we tentatively evaluated the biological activity of water insoluble compounds by adding them in a pure form without solvent into infected blood. In this way some appear to be very active and it was postulated that the effectiveness of such compounds must result from interactions between them and specific blood components.

Pharmacokinetic profile of two different pharmaceutical forms of theophylline (a slow release tablet and a syrup) after multiple dose administration to healthy human volunteers

Due to the narrow therapeutic range of theophyline, plasma concentrations of this drug are monitored in patients undergoing chronic therapy. Slow-release preparations avoid the fluctuations in plasma levels and improve patient compliance. In this study, we have compared the pharmacokinetic profiles of a theophylline slow-release tablet and a syrup form, when administered in multiple doses to healthy adult volunteers. The classification based upon releasing patterns is confirmed.

Immunogold labeling and cerium cytochemistry of the enzyme ecto-5'-nucleotidase in promastigote forms of Leishmania species

We have applied both enzyme cytochemistry and immunological labeling techniques to characterize the enzyme 5'-nucleotidase (5'-Nase), at the ultrastructural level, in promastigote forms of four Leishmania species: Leishmania amazonensis, Leishmania mexicana, Leishmania donovani and Leishmania chagasi. The cerium phosphate staining was localized at the surface of the cell body, the flagellum and the flagellar pocket membranes of all the parasites studied. The immunogold labelling technique confirmed these results. In this report we localized 5'-Nase in L. chagasi and L. amazonensis which have been implicated respectively in visceral and cutaneous forms of leishmaniasis. In addition, we confirmed the localization of this phosphomonoesterase in the other two species studied. The superior quality of the images, obtained with both methodologies, confirms that these parasites possess mechanisms capable of hydrolyzing nucleotide monophosphates, and that the expression of 5'-Nase is associated with the outer surface of the plasma membrane.

Adobe Forms

La tramitació de les Ajudes i Subvencions es considera un dels procediments claus sobre els quals s'ha d'implementar iniciatives d'Administració Electrònica i d'optimització de la gestió. L'objectiu d'aquest projecte és desenvolupar un pilot amb la tecnologia Adobe Forms que implementi el servei de Formularis Electrònics.

Coefficients of Drinfeld modular forms and Hecke operators

"Vegeu el resum a l'inici del document del fitxer adjunt."

Morphological Studies on the Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae, Triatominae) Genital Structures and Eggs of Different Chromatic Forms

Triatoma brasiliensis is considered one of the most important Chagas disease vectors being a widespread species in semiarid areas of northeastern Brazil. The species displays distinct chromatic patterns of the cuticle in different localities. Four populations were analyzed in this study: 1-Caicó, Rio Grande do Norte, it will be called the brasiliensis population; 2-Espinosa, Minas Gerais, the melanica population; 3-Petrolina, Pernambuco, the macromelasoma population, and 4-Juazeiro, Bahia, the darker one in overall cuticle coloration, the Juazeiro population. In order to differentiate the four populations of T. brasiliensis, a comparative morphological analysis of external genital structures and of eggs were carried out. The analysis of the male genital structures evidenced minor individual structural variations that did not correlate with chromatic differences or the geographical origins, emphasizing the importance of examining sufficiently large and representative samples before using minor genital variations for taxonomic diagnosis. By scanning electron microscopy of the egg exochorion, each chromatic population presented a distinct ornamentation pattern. The melanica population differed mainly from the other populations studied since it had about 40.6%, 69.6% and 76.6% more perforations, on each cell exochorion, than the brasiliensis, the Juazeiro and the macromelasoma populations respectively. In the melanica population the perforation layout is also peculiar, with densely distributed perforations over all the egg surface. Morphometric measures of the eggs showed statistically significant differences: the macromelasoma population presented the longest length (2.43 mm) while the shortest was recorded in the brasiliensis population (2.29 mm).

Role of Immune Complexes from Pacients with Different Clinical Forms of Schistosomiasis in the Modulation of In Vitro Granuloma Reaction

Schistosomiasis is a disease whose pathology is strongly related to the granulomatous reaction formed around parasite eggs trapped in host tissues. Studies have shown that the chronic intestinal form (INT) of this infection is associated with a variety of immunoregulatory mechanisms which lead to a diminished granulomatous reaction. Using an in vitro model of granuloma reaction, we show that immune complexes (IC) isolated from sera of INT patients are able to reduce granulomatous reaction developed by peripheral blood mononuclear cells (PBMC) from acute (AC), INT and hepatosplenic (HE) patients to soluble egg antigen (SEA)-conjugated polyacrylamide beads (PB-SEA). This inhibitory activity is also observed in cell proliferation assay of PBMC from INT and HE patients stimulated with SEA and adult worm antigen (SWAP). Furthermore, IC isolated from sera of patients with different clinical forms of the disease are also able to suppress INT patients PBMC reactivity. Therefore, our results show that circulating IC present in sera of patients with different clinical forms of schistosomiasis may down-regulate PBMC reactivity to parasite antigens resulting in a diminished granuloma reaction to parasite eggs

Explicit methods for Hilbert modular forms

We exhibit algorithms to compute systems of Hecke eigenvalues for spaces of Hilbert modular forms over a totally real field. We provide many explicit examples as well as applications to modularity and Galois representations.

Circulating Antigens Levels in Different Clinical Forms of the Schistosoma mansoni Infection

With the aim to evaluate the circulating cathodic antigen (CCA) levels in relation to the different clinical phases of Schistosoma sp. infection a sandwich ELISA using monoclonal antibody 5H11 was performed. The sera of three groups of 25 Brazilian patients with acute, intestinal and hepatosplenic forms of S. mansoni infection were tested and compared to a non-infected control group. Patients and control groups were matched for age and sex and the number of eggs per gram of feces was equally distributed among the three patient groups. Sensitivity of 100%, 72%, 52% of the assay was observed for the intestinal, hepatosplenic and acute toxemic groups respectively. The specificity was 100%. Intestinal and hepatosplenic groups presented CCA levels significantly higher in comparison to those observed for acute patients (F-ratio = 2,524; p = 0.000 and F-ratio = 6,314; p = 0.015 respectively). There was no significant difference of CCA serum levels between hepatosplenic and intestinal groups (F-ratio = 1,026; p = 0.316).

Features of host cell invasion by different infective forms of Trypanosoma cruzi

Through its life cycle from the insect vector to mammalian hosts Trypanosoma cruzi has developed clever strategies to reach the intracellular milieu where it grows sheltered from the hosts' immune system. We have been interested in several aspects of in vitro interactions of different infective forms of the parasite with cultured mammalian cells. We have observed that not only the classically infective trypomastigotes but also amastigotes, originated from the extracellular differentiation of trypomastigotes, can infect cultured cells. Interestingly, the process of invasion of different parasite infective forms is remarkably distinct and also highly dependent on the host cell type.

Age-dependent gain of alternative splice forms and biased duplication explain the relation between splicing and duplication.

We analyze here the relation between alternative splicing and gene duplication in light of recent genomic data, with a focus on the human genome. We show that the previously reported negative correlation between level of alternative splicing and family size no longer holds true. We clarify this pattern and show that it is sufficiently explained by two factors. First, genes progressively gain new splice variants with time. The gain is consistent with a selectively relaxed regime, until purifying selection slows it down as aging genes accumulate a large number of variants. Second, we show that duplication does not lead to a loss of splice forms, but rather that genes with low levels of alternative splicing tend to duplicate more frequently. This leads us to reconsider the role of alternative splicing in duplicate retention.