Tentativas de criação de triatomíneos em laboratório por meio de alimentação "in vitro"

Para simplificar a criação de triatomíneos em laboratório, necessária, por exemplo, à execução do xenodiagnóstico e em estudos de caráter biológico, foi tentada alimentação "in vitro", mediante emprego de sangue, citratado ou desfibrinado, de galinhas abatidas em matadouro avícola. Para avaliação da eficácia desse propósito, observações de duas naturezas, com Triatoma infestans, tiveram lugar, através das seguintes medidas; a) análise do encadeamento de estádios ninfais sucessivos e da exeqüibilidade de satisfatórios acasalamentos, oviposição fértil e adequada reprodução; b) apreciação da infectividade e da viabilidade do Trypanosoma cruzi nos insetos. Como conclusão, ficou evidente que, a despeito da facilitação operacional, o intuito não conduziu ao êxito desejado, já que o procedimento clássico, usado como controle, mostrou-se sempre superior.

Novo processo para triagem de medicamentos na infecção experimental pelo Trypanosoma cruzi

É proposto processo para a triagem da capacidade terapêutica de medicamentos na infecção experimental pelo Trypanosoma cruzi. O método tem base no emprego de triatomíneos parasitados que se alimentam, decorridos períodos diferentes para haver compatibilização com níveis sangüíneos, em camundongos aos quais foi administrado o fármaco sob apreciação; assim, o tubo digestivo do hemíptero participará como estrutura propícia à avaliação. Em observação inicial, ocorreu utilização do benzonidazol, que se mostrou apenas parcialmente ativo, pelo menos de acordo com a maneira de execução do novo procedimento.

Avaliação da atividade terapêutica do itraconazol nas infecções crônicas, experimental e humana, pelo Trypanosoma cruzi

Alguns pesquisadores demonstraram que o intraconzol, "in vitro" e na infecção aguda de animais, possui atividade antiparasitária referente ao Trypanosoma cruzi. Diante dessas observações, decidimos empreender estudo sobre e etapa crônica da parasitose devida a esse protozoário, considerando que ela é mais proeminente sob o ponto de vista médico-assistencial. A propósito, efetuamos apreciações baseadas em modelo composto por camundongos infectados e, também, relacionadas com indivíduos acometidos de doença de Chagas. Usamos 100 mg/kg/dia, por meio de sonda gástrica, durante três meses, e 100 ou 200 mg/dia, pela via oral, respectivamente, no decurso de igual período, sem evidenciarmos efeitos benéficos, pelo menos conforme a metodologia adotada

Exposure to acellular blood products and risk of HIV infection in hemophiliacs from Belo Horizonte, Brazil

Results of a HIV prevalence study conducted in hemophiliacs from Belo Horizonte, Brazil are presented. History of exposure to acellular blood components was determined for the five year period prior to entry in the study, which occurred during 1986 and 1987. Patients with coagulations disorders (hemophilia A = 132, hemophilia B = 16 and coagulation disorders other than hemophilia = 16) were transfused with liquid cryoprecipitate, locally produced, lyophilized cryoprecipitate, imported from São Paulo (Brazil) and factor VIII and IX, imported from Rio de Janeiro (Brazil), Europe, and United States. Thirty six (22%) tested HIV seropositive. The univariate and multivariate analysis (logistic model) demonstrated that the risk of HIV infection during the study period was associated with the total units of acellular blood components transfused. In addition, the proportional contribution of the individual components to the total acellular units transfused, namely a increase in factor VIII/IX and lyophilized cryoprecipitate proportions, were found to be associated with HIV seropositivity. This analysis suggest that not only the total amount of units was an important determinant of HIV infection, but that the risk was also associated with the specific component of blood transfused

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.

Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients

We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.

HYPOXIC STRESS, HEPATOCYTES AND CACO-2 VIABILITY AND SUSCEPTIBILITY TO Shigella flexneri INVASION

SUMMARY Inflammation due to Shigella flexneri can cause damage to the colonic mucosa and cell death by necrosis and apoptosis. This bacteria can reach the bloodstream in this way, and the liver through portal veins. Hypoxia is a condition present in many human diseases, and it may induce bacterial translocation from intestinal lumen. We studied the ability of S. flexneri to invade rat hepatocytes and Caco-2 cells both in normoxic and hypoxic microenvironments, as well as morphological and physiological alterations in these cells after infection under hypoxia. We used the primary culture of rat hepatocytes as a model of study. We analyzed the following parameters in normoxic and hypoxic conditions: morphology, cell viability, bacterial recovery and lactate dehydrogenase (LDH) released. The results showed that there were fewer bacteria within the Caco-2 cells than in hepatocytes in normoxic and hypoxic conditions. We observed that the higher the multiplicity of infection (MOI) the greater the bacterial recovery in hepatocytes. The hypoxic condition decreased the bacterial recovery in hepatocytes. The cytotoxicity evaluated by LDH released by cells was significantly higher in cells submitted to hypoxia than normoxia. Caco-2 cells in normoxia released 63% more LDH than hepatocytes. LDH increased 164% when hepatocytes were submitted to hypoxia and just 21% when Caco-2 cells were in the same condition. The apoptosis evaluated by Tunel was significantly higher in cells submitted to hypoxia than normoxia. When comparing hypoxic cells, we obtained more apoptotic hepatocytes than apoptotic Caco-2 cells. Concluding our results contribute to a better knowledge of interactions between studied cells and Shigella flexneri. These data may be useful in the future to define strategies to combat this virulent pathogen.

Entamoeba histolytica and Entamoeba dispar infections as detected by monoclonal antibody in an urban slum in Fortaleza, Northeastern Brazil

In this study the authors used the Elisa-based antigen detection tests that distinguish E. histolytica from E. dispar to examine the prevalence of E. histolytica infection in individuals from an urban slum in Fortaleza, Northeastern, Brazil. This test has a sensitivity and specificity that is comparable to PCR and isoenzyme analysis, which is the gold standard. Single stools samples were obtained from 735 individuals. The prevalence of E. histolytica infection was 14.9% (110/735) and 25.4%(187/735) for E. dispar-E. histolytica complex. The most affected age group for E. histolytica /E. histolytica-E. dispar infection was the 1-5 year olds but there was no remarkable decrease with age. There was no significant difference in colonization rates between males and females. The results from this survey demonstrate that E. histolytica is highly prevalent in the Community studied. Furthermore, it offers promise for the antigen detection test as a sensitive and technically simple tool for detecting E. histolytica infection in the field.

Chagas disease as a mechanistic model for testing a novel hypothesis

The association between depression and cardiovascular disease is well documented. Nevertheless, the process through which they are linked remains unknown, as does the direction of this relationship. Studies have suggested both that depression is a risk factor for heart disease and that heart disease is a risk factor for depression. A number of studies have established that a relationship exists between depression and inflammation, with alterations in the levels of inflammatory markers (IL-1, IL-6, TNF-alpha and others). Depressive symptoms have also been identified in many diseases characterized by inflammatory processes e.g. rheumatoid arthritis, bronchial asthma, diabetes, tuberculosis and cardiovascular diseases. In this brief viewpoint, we explain and propose how to use Chagas disease, a disorder characterized by inflammatory processes and leading to cardiovascular and autonomic problems, as a model for studying the directionality of the relationship between heart disease and depression.

Evolução da prevalência de parasitoses intestinais em escolares em Caxias do Sul, RS

Relatos da prevalência das parasitoses intestinais no Brasil são pontuais e têm sido descritos em diferentes populações, tornando difícil um diagnóstico abrangente. Visando estudar a variação em 35 anos da prevalência de enteroparasitoses em escolares de Caxias do Sul, RS, foram avaliados 9.787 exames parasitológicos de fezes realizados por centrífugo-sedimentação. Resultaram positivas 5.655 (58%) amostras sendo mais prevalente a infestação por Ascaris lumbricoides (47%), Trichuris trichiura (36%), Enterobius vermicularis (8%) e os protozoários: Giardia lamblia (24%) e Entamoeba coli (20%). A prevalência geral diminuiu de 89% para 37%, com um decréscimo médio de 1,4% ao ano. Houve redução na prevalência de Ascaris lumbricoides de 61 para 26% e de Trichuris trichiura de 38 a 18%. Para Giardia lamblia não houve alteração significativa. A prevalência de Entamoeba coli cresceu de 29 a 46%. Os decréscimos obtidos na prevalência dos helmintos são provavelmente devidos às melhorias da infra-estrutura e às ações formativas desenvolvidas nas escolas.

Outbreak of laboratory-acquired Brucella abortus in Brazil: a case report

Human brucellosis is an occupational disease affecting workers in slaughterhouses, butcher shops and the milk and dairy product industry as well as individuals who work in clinical or research laboratories. We report the first outbreak of a Brucella abortus infection in a Brazilian laboratory and compare the data obtained with reports available in the literature. Exposure was a result of damage to a biological safety cabinet and failure of the unidirectional airflow ventilation system. An epidemiological investigation identified 3 seroconverted individuals, 1 of whom had clinical manifestations and laboratory results compatible with infection at the time of exposure (n=11; attack rate=9.1%).

Toll-like receptor 3 gene polymorphisms are not associated with the risk of hepatitis B and hepatitis C virus infection

INTRODUCTION: The present study investigated the prevalence of two single-nucleotide polymorphisms (SNPs) in the Toll-like receptor 3 (TLR3) gene in patients infected with hepatitis B virus (HBV) and hepatitis C virus (HCV). METHODS: Samples collected from HCV (n = 74) and HBV (n = 35) carriers were subjected to quantitative real-time PCR (qPCR) to detect the presence of the SNPs rs5743305 and rs3775291 in TLR3 and to measure the following biomarkers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), and prothrombin time (PT). A healthy control group was investigated and consisted of 299 HCV- and HBV-seronegative individuals. RESULTS: No significant differences in allele, genotype and haplotype frequencies were observed between the investigated groups, and no association was observed between the polymorphisms and histopathological results. Nevertheless, genotypes TA/AA (rs5743305) and GG (rs3775291) appear to be associated with higher levels of ALT (p<0.01), AST (p<0.05) and PT (p<0.05). In addition, genotypes TT (rs5743305; p<0.05) and GG (rs3775291; p<0.05) were associated with higher GGT levels. CONCLUSIONS: This genetic analysis revealed the absence of an association between the polymorphisms investigated and susceptibility to HBV and HCV infection; however, these polymorphisms might be associated with a greater degree of biliary damage during the course of HCV infection.

Vocalizations of primary forest frog species in the Central Amazon.

The calls of 18 species of Amazonian forest frogs were recorded in 3 localities: the Tapajos National Park near Itaituba, the Reserva Ducke near Manaus, and the INPA-WWF reserves near Manaus. Structural and time parameters and sonographs of these calls including previously undescribed vocalization by 10 species are presented. Unlike open habitat species, several forest frong species characteriscally demonstrated one on more of the following temporal parameters: very low call rates, sporadic intervals, infrequent nights of calling and synchronized chorusing. It is hypothesized that predation has influenced the evolution of vocal behaviour in Amazonian forest frogs.

A NEW SPECIES OF Rhacodiaptomus Kiefer, 1936, FROM THE BRAZILIAN AMAZON (CRUSTACEA:COPEPODA: CALANOIDA)

A new species of Calanoid copepod, Rhacodiaptomus besti,is described from material collected in the Igarapé São Pedro, Rio Jamari, State of Rondônia, and Lago Amanã, Rio Japurá, State of Amazonas, in Western Amazonia. A detailed morphological analysis of the species was undertaken in order to provide a basis for future studies on inter and intrageneric relationships.