Trypanocidal activity and acute toxicity assessment of triterpene acids

The present study evaluates the in vitro and in vivo trypanocidal activity of ursolic acid and oleanolic acid against the Bolivia strain of Trypanosoma cruzi. Their acute toxicity is also assessed on the basis of median lethal dose (DL50) determination and quantification of biochemical parameters. Ursolic acid is the most active compound in vitro, furnishing IC50 of 25.5 mu M and displaying 77% of trypomastigote lysis at a concentration of 128 A mu M. In agreement with in vitro assays, the results obtained for the in vivo assay reveals that ursolic acid (at a dose of 20 mg/Kg/day) provides the most significant reduction in the number of parasites at the parasitemic peak. Results concerning the LD50 assay and the biochemical parameters evaluated in the present study demonstrate that these substances can be safely used on an experimental basis.

Experimental Chagas` disease in orchiectomized Calomys callosus infected with the CM strain of Trypanosoma cruzi

The incidence and progression of disorders associated with an unbalanced immune response has among many factors the gender as a contributory factor. The aims of this work were to evaluate the effects of orchiectomy and the immune response during the experimental Trypanosoma cruzi infection. Young adult, male Calomys callous were i.p. inoculated with 1 x 10(5) blood trypomastigotes of the CM strain of T. cruzi and divided in groups: Control, Sham and Castrated. Castrated group displayed significantly lower values for prostate and seminal vesicle weights indicating a drastic drop of testosterone plasmatic levels. Orchiectomized animals also displayed lesser number of blood parasites, enhanced lytic antibody percentage, splenocyte proliferation and NO concentration when compared to its sham and control counterparts, indicating that steroid gonadal ablation actually influences immune response triggering a more efficient cellular and humoral response which led animals to become more resistant against T cruzi infection. (C) 2009 Elsevier Inc. All rights reserved.

Influence of melatonin therapy and orchiectomy on T cell subsets in male Wistar rats infected with Trypanosoma cruzi

Gonadal steroids exert an important influence on the host immune response during infection. Changes resulting from the absence or replacement of gonadal hormones may represent a distinct evolution of a particular parasite. Taking into account the greater susceptibility of males to parasites, the magnitude of the immune response seems to depend on the interaction of many hormones that will act synergistically with other immune cells. The aims of this research were to evaluate the effects of the luck of male sex hormones due to orchiectomy, and the influence of oral administration of melatonin on the immune response of male Wistar rats infected with the Y strain of Trypanosoma cruzi. The percentage of CD3(+) CD4(+) and CD3(+) CD8(+) lymphocyte T cell subsets were evaluated using flow cytometry and the measurement of IL-2 and IL-12. For all parameters examined, a synergistic action of melatonin and orchiectomy on the host`s immune response was observed, promoting an effective response against the parasite during the acute phase of infection. These results offer insight into other possibilities for possibly controlling T. cruzi proliferation through melatonin therapy and also the stimulatory effects on host`s immune response triggered by the absence of male gonadal steroids during the acute phase of infection.

Counterregulation of Th2 immunity by interleukin 12 reduces host defenses against Strongyloides venezuelensis infection

The aim of this study was to investigate the role of interleukin 12 (IL-12) during Strongyloides venezuelensis infection. IL-12(-/-) and wildtype C57BL/6 mice were subcutaneously infected with 1500 larvae of S. venezuelensis. On days 7, 14, and 21 post-infection, we determined eosinophil and mononuclear cell numbers in the blood and broncoalveolar lavage fluid (BALF), Th2 cytokine secretion in the lung parenchyma, and serum antibody levels. The numbers of eggs in the feces and worm parasites in the duodena were also quantified. The eosinophil and mononuclear cell counts and the concentrations of IL-3, IL-5, IL-10, IL-13, and IgG1 and IgE antibodies increased significantly in infected IL-12(-/-) and wild-type mice as compared with uninfected controls. However, the number of eosinophils and mononuclear cells in the blood and BALF and the Th2 cytokine levels in the lungs of infected IL-12-/- mice were greater than in infected wild-type C57BL/6 mice. In addition, serum IgE and IgG1 levels were also significantly enhanced in the infected mice lacking IL-12. Meanwhile, parasite burden and fecal egg counts were significantly decreased in infected IL-12-/- mice. Together, our results showed that the absence of IL-12 upregulates the Th2 immune response, which is important for control of S. venezuelensis infection. (C) 2009 Elsevier Masson SAS. All rights reserved.

A new thrombospondin-related anonymous protein homologue in Neospora caninum (NcMIC2-like1)

Neospora caninum is an Apicomplexan protozoan that has the dog as a definitive host and cattle (among other animals) as intermediate hosts. It causes encephalopathy in dogs and abortion in cows, with significant loss in worldwide livestock. As any Apicomplexan, the parasite invades the cells using proteins contained in the phylum-specific organelles, like the micronemes, rhoptries and dense granules. The aim of this study was the characterization of a homologue (denominated NcMIC2-like1) of N. caninum thrombospondin-related anonymous protein (NcMIC2), a micronemal protein previously shown to be involved in the attachment and connection with the intracellular motor responsible for the active process of invasion. A polyclonal antiserum raised against the recombinant NcMIC2-like1 functional core (thrombospondin and integrin domains) recognized the native form of NcMIC2-like1, inhibited the in vitro invasion process and localized NcMIC2-like1 at the apical complex of the parasite by confocal immunofluorescence, indicating its micronemal localization. The new molecule, NcMIC2-like1, has features that differentiates it from NcMIC2 in a substantial way to be considered a homologue dagger.

Temporal dynamic of the relationship between the parasitic isopod Aporobopyrus curtatus (Crustacea: Isopoda: Bopyridae) and the anomuran crab Petrolisthes armatus (Crustacea: Decapoda: Porcellanidae) in southern Brazil

The prevalence of the parasite Aporobopyrus curtatus in Petrolisthes armatus from southern Brazil was determined, and the effect the parasite had on host reproduction was evaluated. Of all 775 crabs sampled in Araca region from March 2005 to July 2006, 3.2% presented bopyrid parasites. All the parasitized individuals had one branchial chamber occupied by two mature parasites, with no preference for the right or left chamber. Male and female hosts were infested in equal proportions. Parasitized juveniles, large individuals and ovigerous females were not found in our study. The absence of parasitized ovigerous females seems to be insufficient evidence to support the hypothesis of parasitic castration and would require a histological study to confirm their reproductive death. The percentage of infestation observed in our study (3.1%) is lower than the one found in other studies and it could indicate the existence of factor(s) regulating the density of A. curtatus in the Araca region. At least in this population, the low but constant presence of the bopyrid A. curtatus population did not appear to have a negative effect on the porcellanid population, and parasitized individuals did not play a significant role in the natural history of P. armatus.

Use of proteoliposome as a vaccine against Trypanosoma cruzi in mice

We have generated proteoliposomes carrying proteins of Topanosoma cruzi for use as immunogens in BALB/c mice. T cruzi trypomastigote and amastigote forms were sonicated and mixed with SDS, with 94% recovery of soluble proteins. To prepare proteoliposomes, we have used a protocol in which dipalmitoylphosphatidylcholine, dipalmitoyl-phosphatidylserine and cholesterol were incubated with the parasite proteins. BALB/c mice immunized with 20 mu g were able to generate antibodies which, in Western blotting, reacted with the proteins of T cruzi. We further investigated the ability of peritoneal cells from immunized mice to arrest the intracellular replication of trypomastigotes, in vitro. After 72h of culture, the number of intracellular parasites in immunized macrophages decreased significantly, as compared to controls. Despite the fact that exposure of mice to T cruzi proteins incorporated into proteoliposomes generate antibodies and activate macrophages, the immunized mice were not protected against T cruzi intraperitoneal challenge. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Characterization of rat behavior in the elevated plus-maze using a directed graph

The elevated plus-maze is a device widely used to assess rodent anxiety under the effect of several treatments, including pharmacological agents. The animal is placed at the center of the apparatus, which consists of two open arms and two arms enclosed by walls, and the number of entries and duration of stay in each arm are measured for a 5-min exposure period. The effect of an anxiolytic drug is to increase the percentage of time spent and number of entries into the open arms. In this work, we propose a new measure of anxiety levels in the rat submitted to the elevated plus-maze. We represented the spatial structure of the elevated plus-maze in terms of a directed graph and studied the statistics of the rat`s transitions between the nodes of the graph. By counting the number of times each transition is made and ordering them in descending frequency we represented the rat`s behavior in a rank-frequency plot. Our results suggest that the curves obtained under different pharmacological conditions can be well fitted by a power law with an exponent sensitive to both the drug type and the dose used. (C) 2009 Elsevier B.V. All rights reserved.

Identification of Plasmodium relictum causing mortality in penguins (Spheniscus magellanicus) from Sao Paulo Zoo, Brazil

This study reports avian malaria caused by Plasmodium relictum in Magellanic Penguins (Spheniscus magellanicus) from Sao Paulo Zoo. The disease was highly infective among the birds and was clinically characterized by its acute course and high mortality. The penguins of Sao Paulo Zoo were housed for at least 2 years without malaria; however, they had always been maintained in an enclosure protected from mosquito exposure during the night period. When they presented pododermatitis, they were freed at night for a short period. sao Paulo Zoo is located in one of the last forest remnants of the city, an area of original Atlantic forest. In the winter, the space destined for Zoo birds is shared with migratory species. Hence the possibility exists that the disease was transmitted to the penguins by mosquitoes that had previously bitten infected wild birds. Avian malaria parasites are transmitted mainly by mosquitoes of the genera Aedes and Culex, common vectors in the Atlantic forest. In this study, one Culex (Cux.) sp. was found, infected with P. relictum. There are diverse problems in housing distinct species of animals in captivity, principally when occupying the same enclosure, since it facilitates the transmission of diseases with indirect cycles, as is the case of Plasmodium spp., because certain species that cause discrete infections in some bird species can become a serious danger for others, especially penguins, which do not possess natural resistance. Thus, serious implications exist for periodically testing and administrating malaria therapy in captive penguins potentially exposed to mosquitoes during the night period, as well as other captive birds from Sao Paulo Zoo. (C) 2010 Elsevier B.V. All rights reserved.

Uveitis in celiac disease with an excellent response to gluten-free diet: third case described

To describe the case of a patient with celiac disease who achieved a complete response to a gluten-free diet. A 28-year-old woman presented with diarrhea, oral ulcers, and refractory uveitis of 2.5-years duration. She was treated with prednisone, mydriatic drops, and infliximab with no response. She was referred to our hospital at which point her previous diagnosis of uveitis was confirmed; she was also diagnosed with right-sided sacro-iliitis. The patient did not have arthritis or any skin conditions. Three tests for fecal parasites and a fecal leukocyte were negative. Endoscopy revealed atrophic appearance of the duodenal mucosa. Biopsy showed atrophy of the duodenal villi with intra-epithelial lymphocytes, hyperplasia of the crypts, and chronic inflammatory infiltrate. The search for antiendomysial antibody was > 1/1,280. The patient was started on a gluten-free diet and after 3 months demonstrated significant improvement of gastrointestinal symptoms and uveitis, as well as a reduction of antiendomysial antibodies (1/80). After 6 months, there was complete remission of gastrointestinal symptoms and total control of uveitis. The antiendomysial antibody was negative at that time. Clinical uveitis as a manifestation of celiac disease has been described in only two cases in the literature. This case study is the third to demonstrate that uveitis is a clinical symptom that can be addressed in patients with celiac disease.

Galectin-3 plays a modulatory role in the life span and activation of murine neutrophils during early Toxoplasma gondii infection

Galectins are beta-galactoside-binding lectins involved in several biological processes and galectin-3 (Gal-3) is related to modulation of immune and inflammatory responses. This study aimed to evaluate the role of Gal-3 in the life span and biological functions of murine neutrophils during in vitro infection by virulent Toxoplasma gondii RH strain. Inflammatory peritoneal neutrophils (N phi) from C57BL/6 wildtype (WT) and Gal-3 knockout (KO) mice were cultured in the presence or absence of parasites and analyzed for phosphatidylserine (PS) exposure and cell death using Annexin-V and propidium iodide staining, and cell viability by MU assay. Cell toxicities determined by lactate dehydrogenase (LDH), degranulation by lysozyme release, and cytokine production were measured in NO culture supernatants. Phorbol myristate acetate (PMA)- or zymosan-dependent reactive oxygen species (ROS) were measured in N phi cultures. Our results demonstrated that Gal-3 is involved in the increase of the viable Not. number and the decrease of PS exposure and cell death following T. gondii infection. We also observed that Gal-3 downmodulates gondii-induced N phi toxicity as well as N phi degranulation regardless of infection. Furthermore, Gal-3 expression by N phi was associated with increased levels of IL-10 in the beginning and decreased levels of TNF-alpha later on, regardless of parasite infection, as well as with decreased levels of IL-6 and increased IL-12 levels, following early parasite infection. Our results also showed that Gal-3 suppresses PMA- but not zymosan-induced ROS generation in N phi following T. gondii infection. In conclusion, Gal-3 plays an important modulatory role by interfering in N phi life span and activation during early T gondii infection. (C) 2009 Elsevier GmbH. All rights reserved.

Helminthic Diseases in the Abdomen: An Epidemiologic and Radiologic Overview

Helminthic diseases have a worldwide distribution. They affect billions of people in endemic areas and can result in serious clinical complications. Some parasites have a human gastrointestinal life cycle with resultant abdominal manifestations. However, the symptoms of helminthic diseases are usually nonspecific. Radiologic imaging, along with the identification of risk factors, may help narrow the differential diagnosis. To avoid diagnostic delays, radiologists should be familiar with the geographic distribution, transmission cycle, and characteristic and atypical manifestations of common helminthic diseases at abdominal imaging with radiography, computed tomography, magnetic resonance imaging, and ultrasonography. Awareness of the clinical, epidemiologic, and pathogenic characteristics of these diseases also may be helpful for narrowing the diagnosis when imaging features are nonspecific. (c) RSNA, 2010 . radiographics.rsna.org

Gastroduodenal opportunistic infections and dyspepsia in HIV-infected patients in the era of Highly Active Antiretroviral Therapy

Background and Aim: Dyspeptic symptoms are frequently reported by human immuno-defficiency virus (HIV)-infected patients under highly active antiretroviral therapy. Whether opportunistic infections are a cause of dyspepsia is still unknown. In this study we prospectively compare the prevalence of gastrointestinal opportunistic infections in dyspeptic versus non-dyspeptic HIV-infected patients with advanced immunodeficiency. Patients and Methods: Six hundred and ninety HIV-infected patients under highly active antiretroviral therapy underwent esophagogastroduodenoscopy with mucosal biopsies from the stomach and duodenum. Group 1: 500 patients (161 women, 339 men; mean age 38.8 years; mean CD4 count 154.3 cells/mm(3) with dyspeptic symptoms such as epigastric pain, nausea, vomiting and fullness. Group 2: 190 patients (169 men, 21 women; mean age 40.7 years; mean CD4 count 171.6 cell/mm(3)) with no dyspeptic symptoms. Results: Group 1: Gastrointestinal opportunistic infections were observed in eight (1.6%), and non-opportunistic parasites in two (0.4%), patients. They were: Cytomegalovirus (four patients), Cryptosporidium sp. (two patients), Schistosoma mansoni sp. (one patient), Strongyloides stercoralis (one patient) and Giardia sp. (two patients). In five patients esophagogastroduodenoscopy showed no mucosal lesions. Group 2: Giardia sp. was detected in two patients (1.1%: P = 0.07947). Conclusion: Gastrointestinal opportunistic infections were shown in a small number of HIV-infected patients under highly active antiretroviral therapy with advanced immunodeficiency. Although gastrointestinal opportunistic infections were detected exclusively in the dyspeptic patient group, they could not be related to these symptoms, since the number of infected patients was not statistically significant. To correctly diagnose opportunistic infections, multiple biopsy specimens may be necessary even from normal-appearing mucosa.

Identification and chromosomal localization of one locus of Leishmania (L.) major related with resistance to itraconazole

Ergosterol is an important compound responsible to maintain integrity and fluidity of Leishmania spp. membranes. Starting from an overexpression/selection method, our group has isolated and mapped nine different loci of Leishmania (L.) major related to resistance against two inhibitors of the ergosterol biosynthesis pathway, terbinafine (TBF) and itraconazole (ITZ). Individual functional analysis after overexpression induction of these loci in the presence of TBF and/or ITZ [or the ITZ analog ketoconazole (CTZ)] have shown low but significant levels of resistance after transfection into L. major wild-type parasites. In this work, we have shown the insert mapping and chromosomal identification of one of these loci (cosItz2). Functional analysis experiments associated with chromosomal localization by comparison at genomic database allowed us to identify two prospective gene-protein systems not related to the ergosterol biosynthesis and capable to confer wild-type cells resistance to ITZ-CTZ after transfection. We expected that this approach can open new insights for a better understanding of mechanisms of ITZ-CTZ action and resistance in Leishmania resulting in new strategies for the leishmaniasis treatment.

Usefulness of qualitative polymerase chain reaction for Trypanosoma cruzi DNA in endomyocardial biopsy specimens of chagasic heart transplant patients

BACKGROUND: Chagas` disease reactivation (CDR) after heart transplantation is characterized by relapse of the infectious disease, with direct detection of Trypanosoma cruzi parasites in blood, cerebrospinal fluid, or tissues. CDR affecting the myocardium induces lymphocytic myocarditis and should be distinguished from acute cellular rejection in endomyocardial biopsy (EMB) specimens. METHODS: We performed retrospectively qualitative polymerase chain reaction for T cruzi DNA using 2 sets of primers targeting nuclear DNA (nDNA) or kinetoplast DNA (kDNA) in 61 EMB specimens of 11 chagasic heart transplant recipients who presented with CDR. Thirty-five EMB specimens were obtained up to 6 months before (pre-CDR group) and 26 up to 2 years after the diagnosis of CDR. The control group consisted of 6 chagasic heart transplant recipients with 18 EMB specimens who never experienced CDR. RESULTS: Amplification of kDNA occurred in 8 of 35 (22.9%) EMB specimens of the pre-CDR group, in 5 of 18(27.8%) of the control group, and in 17 of 26(65.4%) EMB specimens obtained after the successful treatment of CDR. Amplification of nDNA occurred in 3 of 35 (8.6%) EMB specimens of the pre-CDR group, 0 of 18 (0%) of the control group, and 6 of 26 (23.1%) EMB specimens obtained after the successful treatment of CDR. CONCLUSIONS: Amplification of kDNA in EMB specimens is not specific for the diagnosis of CDR, occurring also in patients with no evidence of CDR (control group). However, amplification of nDNA occurred in a few EMB specimens obtained before CDR, but in none of the control group specimens. Qualitative PCR for T cruzi DNA in EMB specimens should not be used as a criterion for cure of CDR because it can persist positive despite favorable clinical evolution of the patients. J Heart Lung Transplant 2011;30:799-804 (C) 2011 International Society for Heart and Lung Transplantation. All rights reserved.