Showing papers by "Oswaldo Cruz Foundation published in 1998"

Cryptococcus neoformans var. gattii--evidence for a natural habitat related to decaying wood in a pottery tree hollow.

Abstract: To study hollows of living trees as the natural habitat of Cryptococcus neoformans in an endemic area of cryptococcosis in the northeastern Brazilian region, samples of decaying wood were collected inside the hollows, plated on niger seed agar and inoculated into mice and hamsters. Identification of C. neoformans was based on morphological and physiological tests. Canavanine-glycine-bromothymol medium was used to screen the varieties and Crypto Check Iatron Kit to serotype the isolates. For a period of 29months C. neoformans var. gattii serotype B was isolated repeatedly from the hollow of a pottery tree (Moquilea tomentosa), pointing to the natural occurrence of C. neoformans var. gatti in decaying wood forming hollows in living trees. Evidence for anatural habitat of the variety gattii other than that related to Eucalyptus camaldulensis are discussed.

Mutagenicity testing of (±)-camphor, 1,8-cineole, citral, citronellal, (−)-menthol and terpineol with the Salmonella/microsome assay

Abstract: The essential oils and their monoterpenoid constituents have been widely used as fragrances in cosmetics, as flavouring food additives, as scenting agents in a variety of household products, as active ingredients in some old drugs, and as intermediates in the synthesis of perfume chemicals. The present study was undertaken to investigate the mutagenic potential of six monoterpenoid compounds: two aldehydes (citral and citronellal), a ketone ((+/-)-camphor), an oxide (1,8-cineole, also known as eucalyptol), and two alcohols (terpineol and (-)-menthol). It is part of a more comprehensive toxicological screening of monoterpenes under way at our laboratory. Mutagenicity was evaluated by the Salmonella/microsome assay (TA97a, TA98, TA100 and TA102 tester strains), without and with addition of an extrinsic metabolic activation system (lyophilized rat liver S9 fraction induced by Aroclor 1254). In all cases, the upper limit of the dose interval tested was either the highest non-toxic dose or the lowest dose of the monoterpene toxic to TA100 strain in the preliminary toxicity test. No mutagenic effect was found with (+/-) camphor, citral, citronellal, 1,8-cineole, and (-) menthol. Terpineol caused a slight but dose-related increase in the number of his+ revertants with TA102 tester strain both without and with addition of S9 mixture. The results from this study therefore suggest that, with the exception of terpineol, the monoterpenoid compounds tested are not mutagenic in the Ames test.

A complexidade das relações entre drogas, álcool e violência

Abstract: This article discuss the complex relations between drugs and violence. Drawing on empirical studies and current forms of discourse, it analyzes conceptual and methodological problems related to the establishment of causal nexuses, risks, and associations. By demonstrating the theoretical and practical difficulties in such associations, it also points to the need for a debate in the field of public health and social policies. The article expresses concern that programs and prevention not be contaminated by fallacies, contributing nothing to an understanding of (or action related to) the social issue of drugs.

Brazilian isolates of Trypanosoma cruzi from humans and triatomines classified into two lineages using mini-exon and ribosomal RNA sequences.

Abstract: Traditional molecular and biochemical methods, such as schizodeme analysis, karyotyping, DNA fingerprinting, and enzyme electrophoretic profiles, have shown a large variability among Trypanosoma cruzi isolates. In contrast to those results, polymerase chain reaction (PCR) amplification of sequences from the 24S alpha ribosomal RNA gene and from the mini-exon gene nontranscribed spacer indicated a dimorphism among T. cruzi isolates, which enabled the definition of two major parasite lineages. In the present study, 86 T. cruzi field stocks (68 isolated from humans with defined presentations of Chagas' disease and 18 from triatomines) derived from four Brazilian geographic areas were typed by the PCR assay based on the DNA sequences of the mini-exon and 24S alpha rRNA genes. These stocks were ordered into the two major T. cruzi lineages. Lineage 1 was associated mainly with human isolates and lineage 2 with the sylvatic cycle of the parasite.

Amamentação: um híbrido natureza-cultura

Abstract: Este articulo consiste en un ensayo cuyo objetivo es: a partir de una revision bibliografica, discutir la relacion entre la proposicion de Bruno Latour sobre naturaleza-civilizacion y amamantacion. En torno esta proposicion, teniendo como referencia una vision epistemologica, se busca establecer dialogo con diferentes trabajos en el sentido de aportar para profundizar el asunto en el ambito de la salud publica. Inicialmente, la paradoja para destetar queda en el encenario de los conocimentos y de las practicas de amamantacion. El analisis acompana las relaciones naturaleza-ciencia y civilizacion-sociedad presentes en el interior de la amamantacion. Para finalizar, la discusion se encamina para el lidiar con la amamantacion, mientras un hibrido entre la naturaleza y cultura, apuntando a un nuevo cuestionamiento para la continuidad del debate sobre la tematica en cuestion.

Sobre participação popular: uma questão de perspectiva

Abstract: The idea of popular participation is related to the distribution of public funds by government agencies and the popular classes' needs. Although the history of popular participation dates back to the late 19th century, it was during the 1980s that popular manifestations reached their peak in Brazil. The present context of globalization and neoliberalism have led to changes in the relationships between authorities and civil society, and an impasse has been created in negotiations. This context of impasse has fostered a reflection on the different forces acting within civil society and the various demands raised by them. The author's hypothesis is that the mediators in this process (middle-class and technical professionals), working together in popular participation with the popular classes, experience difficulties in perceiving the latter's interests and evaluations of reality. The popular classes' disbelief in Brazilian politics encourages them to solve their problems by forms of participation different than those practiced historically.

Mapping and Identification of the Major Cell Wall-Associated Components of Mycobacterium leprae

Abstract: Mycobacterium leprae, an obligate intracellular pathogen, can be derived only from host tissue and thus affords the opportunity to study in vivo-expressed products responsible for the particular pathogenesis of leprosy. Despite considerable progress in the characterization of the proteins and secondary gene products of M. leprae, there is little information on the nature of the proteins associated with the cell envelope. M. leprae has been fractionated into its major subcellular components, cell wall, cytoplasmic membrane, and soluble cytosol. A number of biochemical markers, including diaminopimelic acid content, monosaccharide composition, mycolic acid, and glycolipid distribution, were applied to their characterization, and two-dimensional gel electrophoresis was used to map the component proteins. A total of 391 major proteins spots were resolved, and 8 proteins were identified based on their reactivity to a panel of monoclonal antibodies and/or relative pI size. Microsequencing of six protein spots present in the cell wall fraction allowed identification of new proteins, including the protein elongation factor EF-Tu and a homolog for the Mycobacterium tuberculosis MtrA response regulator. These results, together with previous studies, contribute to the progressive knowledge of the composition of the in vivo-expressed proteins of M. leprae.

Maps of epidemiological rates: a Bayesian approach

Abstract: This article presents statistical methods recently developed for the analysis of maps of disease rates when the geographic units have small populations at risk. They adopt the Bayesian approach and use intensive computational methods for estimating risk in each area. The objective of the methods is to separate the variability of rates due to differences between regions from the background risk due to pure random fluctuation. Risk estimates have a total mean quadratic error smaller than usual estimates. We apply these new methods to estimate infant mortality risk in the municipalities of the State of Minas Gerais in 1994.

Macroscopic agglutination test for rapid diagnosis of human leptospirosis

Abstract: A commercially available slide agglutination test (SAT) for the diagnosis of human leptospirosis was evaluated by comparing it to an immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and to the microscopic agglutination test (MAT). For all 108 patients, leptospirosis was diagnosed on the basis of a fourfold or greater increase in titer by MAT (seroconversion), and all but 1 of 245 controls were MAT negative (titers, <1:100). Both SAT and the IgM ELISA failed to detect one case of infection (sensitivity, 99%). Only 3 of 145 blood donors and none of the 100 patients with other illnesses were SAT positive (specificity, 99%). The overall results were similar for the three tests; however, SAT and ELISA were statistically more sensitive as initial screening tests. For 22% of the patients, the diagnosis of leptospirosis was made earlier by SAT than by MAT. SAT detected 27 (44%) of 62 MAT-negative patients with the first serum sample. ELISA and SAT had very similar results. Follow-up of patients for 1 year after the onset of symptoms showed a decreasing rate of positivity by SAT from the third month on. The rate of positivity by ELISA decreased more slowly, to about 67% by the end of the study. By MAT all patients were persistently reactive. SAT and ELISA seem to be convenient methods for the rapid and early screening for leptospirosis and could replace the less sensitive MAT. ELISA gives less subjective results than SAT and provides information on IgM kinetics, but it can be performed only by the more sophisticated laboratories. SAT is inexpensive, can be performed more quickly and more easily than ELISA, and could be used by the less well equipped laboratories.

Cutaneous scars in American tegumentary leishmaniasis patients: a site of Leishmania (Viannia) braziliensis persistence and viability eleven years after antimonial therapy and clinical cure.

Abstract: Two former patients treated for the cutaneous form of American tegumentary leishmaniasis were reviewed eight and 11 years, respectively, following clinical cure. We were able to isolate Leishmania parasites in a culture of material from the two scar biopsies, and in one of them the parasite was characterized as Leishmania (Viannia) braziliensis. In both cases, the histopathology revealed discreet hyperceratosis and a slight infiltrate of mononuclear cells surrounding and on the walls of the surface and deep dermal vessels. No amastigotes were seen on immunohistochemical or histopathologic examination. The Montenegro skin test result and the in vitro lymphoproliferative response to Leishmania antigen were positive, but no specific IgG and IgM antibodies were detected. Otorhinolaryngologic examination showed no macroscopic alteration in the mucosae. These findings are important for the evaluation and criteria of post-treatment cure.

Absence of lysozyme (muramidase) in the intestinal Paneth cells of newborn infants with necrotising enterocolitis.

Abstract: AIM: To determine immunocytochemically whether preterm and newborn infants with necrotising enterocolitis (NEC) show differences in numbers of lysozyme positive Paneth cells compared with normal controls, and to relate the findings to the possibility that lysozyme deficiency may facilitate the bacterial infections thought to be associated with this condition. METHODS: Tissues from 10 infants with NEC and from 11 matched controls were sectioned and stained immunocytochemically for lysozyme. Differences in the numbers of Paneth cells and degree of lysozyme positivity in the tissues were assessed. RESULTS: Tissues from NEC patients showed no, or very few, lysozyme positive Paneth cells, whereas controls showed strong positive staining. CONCLUSIONS: A deficiency or developmental defect in Paneth cells, resulting in an absence of lysozyme, may render the intestine more susceptible to bacterial infection, allowing organisms to adhere and translocate across the mucosa. Such enhancement of infection may contribute to the pathogenesis of NEC.

Proposed Standardization of Neisseria meningitidis PorA Variable-Region Typing Nomenclature

Abstract: Neisseria meningitidis isolates are conventionally classified by serosubtyping, which characterizes the reactivities of the PorA outer membrane protein variable-region (VR) epitopes with monoclonal antibodies (MAbs). A newer method (PorA VR typing) uses predicted amino acid sequences derived from DNA sequence analysis. The resulting classification schemes are not standardized, offering conflicting and sometimes irreconcilable data from the two methods. In this paper, we propose a standardization of the PorA VR typing nomenclature that incorporates serologic information from traditional PorA serosubtyping with molecular data from predicted VR sequences. We performed a comprehensive literature and database search, generating a collection of strains and DNA sequences that reflects the diversity within PorA that exists to date. We have arranged this information in a comprehensive logical model that includes both serosubtype and PorA VR type assignments. Our data demonstrate that the current panel of serosubtype-defining MAbs underestimates PorA VR variability by at least 50%. Our proposal for VR typing is informative because amino acid sequence and serologic information, when serosubtype-defining MAbs are available, can be deduced simultaneously from the PorA VR designation. This scheme will be useful in future classification and applied epidemiologic studies of N. meningitidis, being a systematic way of selecting PorA vaccine candidates and analyzing vaccine coverage and failure.

Activation-induced T cell death exacerbates Trypanosoma cruzi replication in macrophages cocultured with CD4+ T lymphocytes from infected hosts.

Abstract: Activation-induced cell death (AICD) of CD4 + T lymphocytes was described in infection with Trypanosoma cruzi , but a role for AICD in modulating parasite spread in host cells has not been investigated. In this study, replication of T. cruzi in vitro in murine macrophage (Mφ) monolayers was investigated. Long term (5 to 13 day) replication of infective (trypomastigote) T. cruzi forms was blocked by supernatants from activated (anti-TCR) CD4 + T cells of infected mice or by rIFN-γ. However, when CD4 + T cells from infected mice were cocultured with Mφ and activated by anti-TCR, marked exacerbation of trypomastigote growth in Mφ ensued. The deleterious effect required contact between T cells and infected Mφ. Both anti-Fas and TCR activation killed a proportion of CD4 + T cells. Ly-6 activation did not induce AICD and did not exacerbate parasite growth. However, Fas-mediated killing of T cells before Ly-6 activation led to exacerbated parasite growth. Although a minor population, Fas-susceptible cells were the major source of IFN-γ production by activated T cells. Addition of a neutralizing anti-Fas ligand antibody blocked 50 to 60% of CD4 + T cell AICD and reduced trypomastigote growth in T/Mφ cocultures stimulated by anti-TCR. The results demonstrate that in CD4 + T cells from infected mice, the onset of AICD selectively ablates IFN-γ production and up-regulates parasite replication in Mφ in vitro. These findings suggest a deleterious role for AICD in T. cruzi infection.

Community participation and control of endemic diseases in Brazil: problems and possibilities

Abstract: Community participation (CP) is considered one of the most important elements for the control of endemic diseases in poor countries, particularly for prevention and epidemiological surveillance. Mainly affecting the poorest segments of the population, endemic diseases are costly and require specific government action aimed at efficient, egalitarian, universal health system, where CP acts in a guardian, monitoring capacity and entails other specific tasks. Despite its rationality, CP has not been encouraged in countries like Brazil, due to the highly centralized nature of political power and activity. Several examples and situations of CP in Brazilian endemic diseases are described and discussed in the article. CP for endemic disease control should be seen as an ongoing social process, a profound social exercise, and a great challenge for the country as a whole and the new Unified Health System now being implemented in Brazil.

Genetic Diversity in Natural Populations of New World Leishmania

Abstract: Our results have shown the wide diversity of parasites within New World Leishmania Biochemical and molecular characterization of species within the genus has revealed that much of the population heterogeneity has a genetic basis The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, although occasional bouts of sexual reproduction can not be ruled out Genetic variation is extensive with some clones widely distributed and others seemingly unique and localized to a particular endemic focus Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas Future research using molecular techniques should aim to identify and follow Leishmania types in nature and correlate genetic typing with important clinical characteristics such as virulence, pathogenicity, drug resistance and antigenic variation The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents

Direct assessment in vivo of the efficacy of combined single-dose ivermectin and diethylcarbamazine against adult Wuchereria bancrofti.

Abstract: When ivermectin and diethylcarbamazine (DEC) are given simultaneously in a single dose to persons with Wuchereria bancrofti infection, the resulting suppression of microfilaraemia is more profound and sustained than when either drug is given alone. To assess whether this effect is a result of enhanced macrofilaricidal efficacy, we used ultrasound to monitor the adult worms in the scrotal area of men with W. bancrofti microfilaraemia. Twenty-one men were treated simultaneously with DEC (6 mg/kg) and either 200 μg/kg or 400 μg/kg of ivermectin (11 and 10 men, respectively). Ten other men received a single 200 μg/kg dose of ivermectin followed 5 d later by a 6 mg/kg dose of DEC (sequential treatment). All men became amicrofilaraemic after treatment and all except one remained so for one year. Cessation of adult worm movement, indicative of death of all the adult worms in a given ‘nest’, was observed in none of 30 nests in men who received simultaneous treatment and in 3 of the 19 nests (16 %) in the men who received sequential treatment (P = 0.05). Scrotal nodules were detected in 5 of 21 men (24%) who received simultaneous treatment and in 8 men (80%) who received sequential treatment (P

Smoking in Latin America: a major public health problem

Abstract: Smoking has become a major public health problem in Latin America, and its scope varies from country to country. Despite difficulties in obtaining methodologically consistent data for the region, we analyzed the results from prevalence surveys in 14 Latin American countries. Smoking prevalence among men varied from 24.1% (Paraguay) to 66.3% (Dominican Republic) and among women from 5.5% (Paraguay) to 26,6% (Uruguay). By applying point prevalence data to the stage model of the tobacco epidemic in developed countries, we concluded that the Latin American countries are in stage 2, i.e., with a clearly rising prevalence among men, a prevalence for women that is beginning to increase, and mortality attributable to smoking among men still not reflecting peak prevalence. None of the countries analyzed appeared to have reached stage 3, in which one observes a downward trend in prevalence of smoking among men and peak prevalence among women, with broad impact on tobacco-related mortality. The only exception appears to be Paraguay, which is still emerging from stage 1, i.e., with low prevalence rates among men, too. Nevertheless, high lung cancer mortality rates in Uruguay and Argentina are comparable to those of the developed countries.

Associated anomalies in individuals with polydactyly.

Abstract: An epidemiological analysis of the association of polydactyly with other congenital anomalies was performed in 5,927 consecutively born polydactyly cases. They were grouped into three categories: duplicated fifth digit, duplicated first digit, and rare polydactylies; also into isolated or associated groups, if other birth defects were or were not observed in the same infant. Associated cases were further subdivided into: combined, if the other defect was a limb defect; syndromic, if a non-limb defect constituted a recognized causal or pathogenetic entity; and MCA, if a non-limb defect did not constitute a recognized entity. In 14.6% of the 5,927 polydactyly cases studied, polydactyly was not the only congenital anomaly. This associated proportion was minimal for postaxial (11.8%), intermediate for preaxial-I (20.0%), and maximal for rare polydactyly (54.9%). Duplication of the fifth toe plus syndactyly of fourth and fifth toes, as well as other syndactylies adjacent to the duplicated digit is the most frequent type. Syndactyly of fourth and fifth toes was also combined with a duplicated fifth finger, suggesting the existence of an arrested or amputated in utero sixth toe. Polydactylies are rarely associated with other congenital anomalies except in recognizable syndromes. When syndromes are excluded, most of the significant positive associations disappear. Trisomy 13, Meckel, and Down syndrome explained 255 of the 338 syndromic polydactyly cases. Down syndrome is strongly associated with first-digit duplication, and negatively associated with postaxial polydactyly. The latter could not be explained by maternal age differences among Black and non-Black case sub-sets.

Growth hormone and its receptor are expressed in human thymic cells.

Abstract: GH has been shown to modulate various functions of the thymus. We now demonstrate the production of human GH (hGH) by human thymic cells, and the expression of GH receptors in thymic epithelial cells (TEC) and in thymocytes at different stages of differentiation. The presence of hGH messenger RNA was shown by RT-PCR in both human thymocytes and in primary cultures of TEC. Moreover, immunoreactive hGH material was detected in culture media of thymocytes and TEC with the use of a sensitive immunoradiometric assay. GH receptor gene expression was shown in TEC in primary cultures and in fetal and postnatal TEC lines as well as in thymocytes. By immunocytochemistry, the presence of GH receptors in the various TEC preparations was confirmed. In cytofluorometric studies with the use of a biotinylated anti-GH receptor monoclonal antibody, we could show that GH receptors are predominantly expressed by immature thymocytes: over 90% of CD3− CD4− CD8− CD19− CD34+ CD2+ cells (a phenotype characterizing the most immatu...

Pentoxifylline decreases in vivo and in vitro tumour necrosis factor-alpha (TNF-alpha) production in lepromatous leprosy patients with erythema nodosum leprosum (ENL).

Abstract: Increasing evidence has implicated TNF-alpha as a pivotal molecule involved in the systemic inflammatory manifestations of ENL, an acute inflammatory complication that may occur in the chronic course of leprosy. In the present study, the mechanism of action of pentoxifylline (PTX) as an alternative therapy for management of leprosy reactions has been evaluated. The effect of PTX on TNF-alpha production was examined in leprosy patients at the protein level and at the transcriptional level as well. Treatment of ENL patients with PTX (1200 mg daily) ameliorated the systemic symptoms and favoured the evolution of reactional leprosy lesions. Serum TNF-alpha was assayed before and during treatment with PTX in 15 patients. The increased TNF-alpha levels seen in the circulation during the reaction were dramatically reduced within 3-7 days of therapy. No significant effect on serum IL-6 was noted. In vitro TNF-alpha production was assayed upon culture stimulation with Mycobacterium leprae. A reduction of inducible TNF-alpha in peripheral blood mononuclear cells (PBMC) was seen after 1-2 weeks of in vivo administration of PTX. Furthermore, no effect of the drug on IL-10 secretion was detected in these cultures. A kinetic analysis of the expression of TNF-alpha and IL-6 mRNA at the site of leprosy lesion was performed in six reactional patients by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The amount of TNF-alpha mRNA was increased in the tissue during ENL compared with before the reaction, and decreased thereafter following treatment for reaction (either PTX or thalidomide). These data suggest that PTX inhibits TNF-alpha production in ENL patients both in vivo and in vitro, and it may be useful in the treatment of leprosy patients undergoing ENL.

Ecotopes, Natural Infection and Trophic Resources of Triatoma brasiliensis (Hemiptera, Reduviidae, Triatominae)

Abstract: Triatoma brasiliensis is considered as one of the most important Chagas disease vectors in the northeastern Brazil. This species presents chromatic variations which led to descriptions of subspecies, synonymized by Lent and Wygodzinsky (1979). In order to broaden bionomic knowledge of these distinct colour patterns of T. brasiliensis, captures were performed at different sites, where the chromatic patterns were described: Caico, Rio Grande do Norte (T. brasiliensis brasiliensis Neiva, 1911), it will be called the "brasiliensis population"; Espinosa, Minas Gerais (T. brasiliensis melanica Neiva & Lent 1941), the "melanica population" and Petrolina, Pernambuco (T. brasiliensis macromelasoma, Galvao 1956), the "macromelasoma population". A fourth chromatic pattern was collected in Juazeiro, Bahia the darker one in overall cuticle coloration, the "Juazeiro population". At the sites of Caico, Petrolina and Juazeiro, specimens were captured in peridomiciliar ecotopes and in wilderness. In Espinosa the specimens were collected only in wilderness, even though several exhaustive captures have been performed in peridomicile at different sites of this municipality. A total of 298 specimens were captured. The average registered infection rate was 15% for "brasiliensis population" and of 6.6% for "melanica population". Specimens of "macromelasoma" and of "Juazeiro populations" did not present natural infection. Concerning trophic resources, evaluated by the precipitin test, feeding eclecticism for the different colour patterns studied was observed, with dominance of goat blood in household surroundings as well as in wilderness

Ifn-gamma in human chagas' disease : protection or pathology?

Abstract: An apparently paradoxical role for IFN-γ in human Chagasi disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with benznidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-γ were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-γ were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-γ in human Chagasi disease is discussed in terms of the possibility of a temporal difference in IFN-γ production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-γ production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.