Leishmanicidal activity of Echinaster (Othilia) echinophorus crude extract

In this study, a methanolic extract from Echinaster (Othilia) echinophorus was evaluated for activity against Leishmania amazonensis. The extract showed activity against the promastigote and amastigote forms with IC50 values of 62.9 and 37.5 μg.mL-1 respectively. This extract showed a moderate toxicity on macrophages from BALB/c mice. A dose of 100 mg/kg/day was effective when administered during 15 days by intraperitoneal route to BALB/c mice infected experimentally.

In vitro activity of the clinical pulmonary surfactant Surfacen® against Leishmania amazonensis

Surfacen® is an exogenous natural lung surfactant, composed by phospholipids and hydrophobic proteins, which is applied successfully in Newborn Respiratory Distress Syndrome. In this paper, in vitro activity of Surfacen® against Leishmania amazonensis is described. The product showed activity against the amastigote form found in peritoneal macrophages from BALB/c mice, with an IC50 value of 17.9 ± 3.0 µg/mL; while no toxic effect on host cell was observed up to 200 µg/mL. This is the first report about the antileishmanial activity of Surfacen®.

Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime

In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis.

Expression of TLR2 and TLR4 in lesions of patients with tegumentary american leishmaniasis

OBJECTIVES: The aim of this study was to describe the pattern of expression of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in skin biopsies of patients with American tegumentary leishmaniasis (ATL) caused by Leishmania braziliensis. METHODS: This prospective study evaluated 12 patients with ATL caused by Leishmania braziliensis confirmed by polymerase chain reaction. Immunohistochemistry was performed to determine the expression of TLR2 and TLR4. The number of NK cells, dendritic cells and macrophages in the tissue were calculated. The cytokine expression was determined using the anti-TNF-α, anti-IFN-Γ, anti-IL-1 and anti-IL-6. Double immunostaining reactions were used to determine the cell expressing TLR2 and TLR4. RESULTS: The numbers of cells expressing TLR2 and TLR4 were 145.48 ± 82.46 cell/mm² and 3.26 ± 4.11 cell/mm² respectively (p < 0.05). There was no correlation of TLR2 and TLR4 with the amount of cytokines and the number of NK cells, dendritic cells or macrophages. The double immunostaining revealed that TLR2 was expressed by macrophages. CONCLUSION: In human cutaneous leishmaniasis caused by Leishmania braziliensis, TLR2 is the most common TLR expressed during active disease, mainly by macrophages although without correlation with the amount of cytokines and number of cells.

DISTINCT CELLULAR MIGRATION INDUCED BY Leishmania infantum chagasi AND SALIVA FROM Lutzomyia longipalpis IN A HEMORRHAGIC POOL MODEL

Recruitment of a specific cell population after Leishmania infection can influence the outcome of the disease. Cellular migration in response to Leishmania or vector saliva has been reported in air pouch model, however, cellular migration induced by Leishmania associated with host's blood and vector saliva in this model has not been described. Herein we investigated cellular migration into air pouch of hamster after stimulation with combination of L. chagasi and host's blood and Lutzomyia longipalpis saliva. Migration induced by saliva was 3-fold more than those induced by L. chagasi alone. Additionally, L. chagasi associated with blood and saliva induced significantly even more leukocytes into air pouch than Leishmania alone. L. chagasi recruited a diverse cell population; however, most of these cells seem to have not migrated to the inflammatory exudate, remaining in the pouch lining tissue. These results indicate that L. chagasi can reduce leukocyte accumulation to the initial site of infection, and when associated with vector saliva in the presence of blood components, increase the influx of more neutrophils than macrophages, suggesting that the parasite has developed a strategy to minimize the initial inflammatory response, allowing an unlimited progression within the host. This work reinforces the importance of studies on the salivary components of sand fly vectors of leishmaniasis in the transmission process and the establishment of the infection.

THE RELEVANCE OF NUTRITIONAL STATUS AND HISTOPATHOLOGICAL FINDINGS ON THE INFECTIOUS PROCESS OF BALB/C MICE INOCULATED WITH Lacazia loboi

SUMMARY The aim of this study was to evaluate the effects of the protein-calorie malnutrition in BALB/c isogenic mice infected with Lacazia loboi, employing nutritional and histopathological parameters. Four groups were composed: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. Once malnutrition had been imposed, the animals were inoculated intradermally in the footpad and after four months, were sacrificed for the excision of the footpad, liver and spleen. The infection did not exert great influence on the body weight of the mice. The weight of the liver and spleen showed reduction in the undernourished groups when compared to the nourished groups. The macroscopic lesions, viability index and total number of fungi found in the footpads of the infected mice were increased in G3 when compared to G1. Regarding the histopathological analysis of the footpad, a global cellularity increase in the composition of the granuloma was observed in G3 when compared to G1, with large numbers of macrophages and multinucleated giant cells, discrete numbers of lymphocytes were present in G3 and an increase was observed in G1. The results suggest that there is considerable interaction between Jorge Lobo's disease and nutrition.

Effects of lethal and non-lethal malaria on the mononuclear phagocyte system

The effects ofone non-lethal species ofmalarialparasite, Plasmodium yoelii, and one lethal species, P. berghei, on the mononuclear phagocyte system (MPS) of BALB/c mice were studied. P. yoelii caused a greater and more sustained expansion and activation of the MPS, and the two major populations of spleen phagocytic cells-red pulp and marginal zone macrophages - exhibited a greater increase in numbers in this infection. During the course of P. berghei mataria, the spleen was progressively occupied by haematopoietic tissue and, at the terminal stage of infection, an extensive depletion of lymphocytes and macrophages was apparent. The possibility was suggested that the outcome of mataria may be inftuenced by the particular way the parasite interacts with the MPS.

Evolution of sarcoma 180 (ascitic tumor) in mice infected with Schistosoma mansoni

Mice infected with 60 cercariae of Schistosoma mansoni were more resistant to the sarcoma 180 ascites tumor. Tumor inoculation was performed 50 days after schistosoma infection and the animals were observed and weighed at 48 hours intervals for development and progression of malignancy. In infected mice the weight gain (ascites formation) started later and was shorter than in uninfected Controls. Also, the number of tumor cells into the peritoneal cavity 72h after tumor implantation was shorter in infected group than incontrols. This in creased resistance against a transplantable tumor probably is related to the effect of endotoxin on tumoricidal activity of macrophages activated by the infection. The immunodepression induced by Schistosoma mansoni infection enhances the proliferation of endogenous bacteria increasing the amount of endotoxin absorbed from the gut.

Kinetics of Trypanosoma cruzi destruction in the mouse spleen

Massive destruction of parasitized splenic macrophages was histologically observed at the height of a virulent infection caused by Trypanosoma cruzi (Y strain) in the mouse. This was coincident with a sudden drop in parasitemic curve. Most of the animals died at this point, probably due to the liberation of toxic products, such as TNF, following the massive destruction of parasitized cells. However, parasitized-cell destruction indicated the transition from susceptibility to resistance. Although it has been extensively studied in vitro, this study contributes with the morphological counterpart observed in vivo by optical and electron microscopy. When infected animals were specifically treated during early infection transition to chronic phase was immediately observed without splenic parasitism. Animals that apparently recovered from massive cell-destruction in the spleen showed evidences of a rapid restoration of splenic architecture.

Therapeutic trial in experimental tegumentary leishmaniasis caused by Leishmania (Leishmania) amazonensis. A comparative study between mefloquine and aminosidine

One hundred and eighty-two male inbred C57/BL/6 mice were infected with 3 x 106 Leishmania (Leishmania) amazonensis promastigotes of the MHOM/BR/PH8 strain by means of a subcutaneous injection in the right ear. The animals were separated in three groups: 1) oral mefloquine hydrochloride treatment (16mg/kg/day/10 days), 2) intramuscular aminosidine (Paromomycin®) treatment (20mg/kg/20 days) and 3) control. Twenty six mice of each treated group were sacrificed, one at the end of treatment (nine weeks after inoculation), and one six weeks later (fifteen weeks after inoculation). Control Group animals were sacrificed at weeks six, nine and fifteen after inoculation. There was no significant difference between Group 1 (mefloquine) and Group 3 (control) subjects. Group 2 animals (aminosidine) presented the smallest differences of all, both at the end of the treatment and six weeks later. The histopato-logical parameters have shown the following findings: a) there was no significant difference between the mefloquine treated group and the control group; the group treated with aminosidine showed fewer of vacuolated macrophages than the control group, at week 9 (end of treatment). b) both at the end of treatment and six weeks later, evaluation of tissue necrosis and tissue fibrosis revealed no differences between the treated groups. It was found that six weeks after the end of treatment, mice in the control group presented significantly more severe degrees of fibrosis than mice in the other groups. It can be concluded that mefloquine showed limited therapeutic effect in this experimental model, whereas aminosidine had a significant effect. Nevertheless, neither of them resulted in cure of the lesions.

Histological evaluation of the lesion induced by inoculation of Leishmania mexicana in the cheek pouch of the hamster

We have studied the role of the immune response in the morphology of the leishmaniotic granuloma induced in the cheek pouch of hamsters, an immunologically privileged site, after inoculation of 3 x 10(5) Leishmania mexicana. Animals were histologically and immunologically evaluated until 120 days after inoculation. Independent of the time of sacrifice, the animals were always non-reactors to the footpad test (FPT). At histology, the introduction of L. mexicana in the cheek pouch leads to an abscess that evolves to a granulomatous reaction rich in amastigote forms, and later it leads to resolution, even in the absence of immune response detectable by FPT. Our results demonstrate that the development of immune response is not preponderant for the control of infection induced by L. mexicana inoculated subcutaneously in the cheek pouch of the hamster. It also suggests that the macrophages present in the leishmaniotic granuloma are capable of eliminating this parasite, even in the absence of immune response evaluated by FPT.

Stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes by human monocytes

Monocytes/macrophages play a critical role in the defense mechanisms against malaria parasites, and are the main cells responsible for the elimination of malaria parasites from the blood circulation. We carried out a microscope-aided evaluation of the stages of in vitro phagocytosis of Plasmodium falciparum-infected erythrocytes, by human monocytes. These cells were obtained from healthy adult individuals by means of centrifugation through a cushion of Percoll density medium and were incubated with erythrocytes infected with Plasmodium falciparum that had previously been incubated with a pool of anti-plasmodial immune serum. We described the stages of phagocytosis, starting from adherence of infected erythrocytes to the phagocyte membrane and ending with their destruction within the phagolisosomes of the monocytes. We observed that the different erythrocytic forms of the parasite were ingested by monocytes, and that the process of phagocytosis may be completed in around 30 minutes. Furthermore, we showed that phagocytosis may occur continuously, such that different phases of the process were observed in the same phagocyte.

Cytokine expression in the duodenal mucosa of patients with visceral leishmaniasis

INTRODUCTION: Visceral leishmaniasis (VL) is a neglected tropical disease with a complex immune response in different organs. This pattern of organ-specific immune response has never been evaluated in the gastrointestinal tract. The aim of this study was to determine the in situ immune response in duodenal biopsies on patients with VL. METHODS: A case-control study was conducted on 13 patients with VL in comparison with nine controls. The immune response was evaluated using immunohistochemistry, for CD4, CD8, CD68, IL-4, IFN-γ, TNF-α and IL-10. Histological findings from the villi, crypts and inflammatory process were analyzed. RESULTS: All the cases of VL presented Leishmania antigens. No antigen was detected in the control group. The villus size was greater in the VL patients (p < 0.05). CD68 (macrophages) and CD4 levels were higher in the VL patients (p < 0.05). No differences in the expression of CD8, TNF-α, IL-10 or IL-4 were demonstrated. The number of cells expressing IFN-γ was lower in the VL patients (p < 0.05). CONCLUSIONS: Low levels of cytokines were found in the gastrointestinal tract of patients with VL. This pattern was not found in other organs affected by the disease. Immunotolerance of this tissue against Leishmania could explain these findings, as occurs with intestinal bacteria.

Clinical and laboratory findings in patients with dengue associated with hepatopathy

INTRODUCTION: Hepatic disorders caused by dengue infection may progress to severe manifestations, including mortality and morbidity. Cytokines are involved in it, such as the migration inhibitory factor of macrophages (MIF), tumor necrosis factor (TNF), natural killer cells (NK), B lymphocytes, and macrophages. METHODS: This study was carried out from January to April 2007 at a public hospital from the Federal University of Mato Grosso do Sul, Campo Grande, Brazil. Sixty-eight patients were studied concerning hepatic alterations, with 56 reported having classic dengue, 6 with hemorrhagic dengue grade I, and 6 with hemorrhagic dengue grade II. RESULTS: Among the 56 with classic dengue, 83.3% had aspartate aminotransferase (AST) alterations, and 69.6% had altered alanine aminotransferase (ALT). For those with hemorrhagic dengue grade I, 100% had AST alterations, and 83.3% had altered ALT. All the patients with hemorrhagic dengue grade II had AST and ALT alterations. AST variations reached 22.0 and 907.0, with an average value of 164.6. For ALT, we found variations between 25.0 and 867.0, with an average value of 166.07. There had been statistical significance between dengue clinical shapes and hepatic function markers. CONCLUSIONS: We conclude that the infection was predominant in adults, females, and in those with low income and education. The liver enzymes were of larger amount in hemorrhagic dengue, but there was weak statistical evidence of the clinical manifestations and transaminases. Major signs and clinical symptoms were fever, headache, myalgia, arthralgia, weakness, severe pain behind the eyes, and rashes.

Testicular schistosomiasis as differential diagnosis for testicular nodules: a case report

AbstractDespite its infrequent occurrence, testicular schistosomiasis forming pseudo-tumors can be considered in the differential diagnosis of testicular tumors, especially in areas where the parasitic disease is endemic. In this report, we present a case of testicular schistosomiasis caused by Schistosoma mansoni and mimicking a testicular neoplasm. We describe the patterns of a testicular nodule on ultrasonography and magnetic resonance images in a 46-year-old man. The nodule was removed after a pre-operative diagnosis of a non-malignant lesion. Histology demonstrated granulomas with epithelioid macrophages and eosinophils around S. mansoni eggs within a fibrous tissue that formed a nodular structure.