Leishmania major: anti-leishmanial activity of Nuphar lutea extract mediated by the activation of transcription factor NF-κB.

Here we report the effect of a partially purified alkaloid fraction (NUP) of Nuphar lutea on nuclear factor kappa B (NF-κB) expression and studied its mechanism of toxicity against Leishmania major in C3H mice peritoneal macrophages. NUP was found to be a mixture of thermo-stable dimeric sesquiterpene thioalkaloids containing mainly thionupharidines. The anti-leishmanial activity was shown to be mediated through the activation of NF-κB and increased iNOS production. Additionally, the nitric oxide inhibitor, N(G)-monomethyl-L-arginine (0.5mM) totally reverted the anti-leishmanial effect of NUP (0.25 and 0.5µg/ml). NUP was also shown to act as an anti-oxidant, almost completely inhibiting the macrophage respiratory burst activity. However, no elevated lysozyme (EC3.2.1.17) or ß-galactosidase (EC3.2.1.23) activities were demonstrated in macrophages treated with NUP. This study suggests, that the activity of NUP is mediated by NF-κB activation and the production of nitric oxide which is dependent on the L-arginine:NO pathway.

IL-1-induced inflammation promotes development of leishmaniasis in susceptible BALB/c mice.

The role of host-derived IL-1 on the course of Leishmania major infection in susceptible BALB/c mice was assessed. Manifestations of the disease were more severe in mice deficient in the physiological inhibitor of IL-1, the IL-1 receptor antagonist (IL-1Ra) in comparison with control mice. In mice lacking one of the IL-1 genes (IL-1alpha or IL-1beta), there was delayed development of the disease and more attenuated systemic inflammatory responses. IL-1alpha-deficient mice were slightly more resistant to L. major infection compared with IL-1beta-knockout mice. During disease progression in IL-1Ra KO and control mice, myeloid-derived suppressor cells invaded the spleen, concomitant to suppression of T cell-mediated immunity and expression of systemic high levels of pro-inflammatory cytokines. In IL-1-deficient mice, T(h)1 responses were still apparent, even at late stages of the disease. Thus, dose-dependent effects of IL-1 were shown to influence the pathogenesis of murine leishamaniasis in susceptible BALB/c mice. Physiological and supra-physiological levels of IL-1 in the microenvironment promoted an exacerbated form of disease, whereas sub-physiological doses of IL-1 induced a less progressive disease. Thus, manipulation of IL-1 levels in the host, using the IL-1Ra or specific antibodies, has the potential to alleviate symptoms of visceral manifestations of leishmaniasis.

The immunomodulatory effect of Sambucol on leishmanial and malarial infections.

A nontoxic dose of Sambucol, an immunomodulator commercially sold as an immune stimulator, was examined in murine models of leishmaniasis and malaria. Sambucol causes a shift in the immune response, as demonstrated in human monocyte cultures, to Th1 (inflammation-associated) responses. Treatment of leishmania-infected mice with Sambucol delayed the development of the disease. As there was no direct IN VITRO anti-leishmanial effect, the observed partial protection IN VIVO is most likely related to immune modulation. Although increased Th1 responses are associated with protection from leishmaniasis, they are considered to be the main immunopathological processes leading to cerebral malaria. Administration of Sambucol to mice prior to and following infection with Plasmodium berghei ANKA increased the incidence of cerebral malaria, while administration of Sambucol after infection had no effect on the disease. The results demonstrate how an inflammatory-like response may alleviate or exacerbate clinical symptoms of disease and hint at the importance of administration timing. The overall effect of immunomodulator administration depends on the ongoing immune response and the Th1/Th2 balance determined by both host and parasite defense mechanisms.

Current status and perspectives of the immunotherapy of leishmaniasis.

There is still a need for innovative and alternative therapies against leishmaniasis. Despite recent advances in immunology, effective immunotherapy against the disease has not yet been proven. Live, attenuated and dead parasites, purified and recombinant specific antigens, DNA vaccines as well as DC-based immunization that have been employed in the development of protective vaccine have not yet been adopted as immunotherapeutic agents. Recently, a commercially prophylactic vaccine (Leish-110f) was developed by BioPharm International, by constructing a recombinant fusion protein consisting of TSA (thiol-specific antioxidant), LmSTI1 (L. major stress-inducible protein 1) and LeIF (Leishmania elongation initiation factor). This vaccine, when administered together with the adjuvant monophosphoryl lipid A (MPL), either alone or plus squalene (MPL-SE) or AdjuPrime, protected mice against L. major and L. infantum infections. Also, Leishvacin (Leishvacin, Biobrs, Montes Carlos, State of Minas Gerais, Brazil), a commercial non-living promastigote polyvalent Leishmania vaccine administered either alone or combined with BCG, was found to be highly immunogenic against American CL in humans. Leishvacin alone was also found to be effective as a prophylactic vaccine, sensitizing lymphocytes from normal uninfected humans, which was further accelerated by recombinant GM-CSF. Standardization and additional carefully controlled studies in animals and humans, using these new vaccines and other immunomodulators in conjunction with various chemotherapeutic agents, are still required to determine the optimal conditions for the development of a potent anti-leishmanial immunotherapy and immunochemotherapy.

Taenia multiceps: a rare human cestode infection in Israel.

Brain infestation caused by the metacestode of Taenia multiceps is a rare phenomenon in humans, but is fairly common among sheep in Mediterranean countries. No more than 150 human cases have been reported. In this present study, we report an unusual case of a huge intra-parenchymal cyst in a four-year-old girl caused by T. multiceps. No cross-reactivity between Echinococcus granulosus and T. multiceps antigens was demonstrated. After surgical removal of the cyst, followed by chemotherapeutic treatment with albendazole combined with praziquantel, the child recovered completely.

Huge hemispheric intraparenchymal cyst caused by Taenia multiceps in a child. Case report.

The authors report an unusual case of a huge intraparenchymal cyst in a 4-year-old girl caused by Taenia multiceps infection. After surgical removal of the cyst, the child recovered completely. Brain infestation by coenurus is a rare disease, mainly reported in Africa, with a few case reports from patients in developed countries. Humans, especially young children, become intermediate hosts by ingesting eggs passed in the excrement of a definitive host, usually carnivores. In such cases, high mortality and morbidity rates have been reported. These rates decreased after the introduction of the modem neuroradiological techniques of computed tomography and magnetic resonance imaging.

Anti-amebic antibody activity in patients, determined with antigens prepared from virulent parasites (indirect hemagglutination assay and enzyme-linked immunosorbent assay).

BACKGROUND: The serology of amebiasis is affected by low sensitivity and specificity. OBJECTIVES: To evaluate the advantage of the indirect hemagglutination assay and enzyme-linked immunosorbent assay in the diagnosis of amebiasis, using Entamoeba histolytica soluble antigen (macerated amebic antigens) prepared from four different virulent isolates, continuously cultivated in the presence of the original enteric bacteria. METHODS: Using IHA and ELISA with MAA antigen we examined 147 sera samples from patients with gastrointestinal symptoms, and 11 sera from amebiasis cases (confirmed by microscopy and copro-antigen ELISA). RESULTS: Of 104 of the 147 (70.7%) symptomatic cases that were amebiasis positive by IHA, 81 (55.1%) were positive by MAA-ELISA. In addition, of 11 amebiasis cases confirmed by microscopy and copro-antigen ELISA, 7 (64%) were amebiasis positive by both tests. Four species of bacteria were isolated from the ameba cultures: Escherichia coli, Morganella morganii, Proteus mirabilis, and Streptococcus lactis. Elimination of the bacteria from the cultures by an antibiotics cocktail containing gentamicin, imipenem, piperacillin-tazobactam and vancomycin was the preferred method. Absorption of patients' sera to bacterial antigen prior to serological analysis had only a marginal effect. CONCLUSIONS: These results indicate a correlation of 61% between the ELISA developed in this study and the IHA tests in the diagnosis of amebiasis.

Leishmania major: in vitro and in vivo anti-leishmanial activity of paromomycin ointment (Leshcutan) combined with the immunomodulator Imiquimod.

Paromomycin at 25, 50 and 100 microg/ml, inhibited the growth of Leishmania major amastigotes by 34.5%, 61.2%, 74.9% and 85.4%, 89.9%, 95.7% on the 2nd and the 4th day of treatment in culture, respectively. Methylbenzethonium chloride at 0.1 and 0.5 microg/ml and Imiquimod at 5 and 10 microg/ml, administered separately, inhibited the parasite development by 39.5% and 65.2% and 31.5% and 47.7%, respectively. Imiquimod (5-10 microg/ml) combined with either paromomycin (25, 50 and 100 microg/ml) or methylbenzethonium chloride (0.1 and 0.5 microg/ml) showed an anti-leishmanial additive effect. A 10 day topical treatment, twice daily, with an ointment containing 15% paromomycin and 12% methylbenzethonium chloride (Leshcutan), either undiluted or diluted 1:5 in soft white paraffin combined with 5% Imiquimod cream (Aldara), was as effective as Leshcutan given alone. The present study suggests that a combination of Aldara and Leshcutan is as effective as Leshcutan given alone in the topical treatment of CL caused by L. major.

Repeated treatment of cystic echinococcosis in patients with a long-term immunological response after successful surgical cyst removal.

Six cystic echinococcosis patients underwent surgery for the removal of echinococcal cysts. All were treated with albendazole prior to and following treatment. After surgery, no cysts were detected in five of the six patients examined. Both ELISA and immunoblot analysis have been used to determine specific IgG, IgG4 and IgE activities. Total elimination of IgG and IgG4 was not achieved in any of the patients studied. Prior to the first surgery/treatment, specific IgG, IgG4 and IgE antibodies were demonstrated in all patients, except one who did not show any IgE activity. The first treatment was followed by highly elevated IgE in two patients; in one of them it was further combined with an apparent decrease in IgG activity. Repeated treatment with albendazole given 0.8-8.5 years after the first treatment/surgery was followed by either moderate or highly reduced IgE activity in two patients, respectively, and a slight increase in IgG4 in another patient. A third course of treatment, given 2-2.5 years after the second treatment, barely affected the antibody activities. The present study suggests that anti-echinoccocal antibody activity may remain high many years after successful cyst removal. Determination of IgG, IgG4 and IgE responses is preferable for the assessment of treatment results. The presence of anti-echinococcal antibodies after surgery with no cyst detection does not necessarily indicate an active echinococcal infection.

Immunological responses and the pattern of disease in mice infected with transfected Leishmania major constitutively expressing active IL-1alpha.

Immunity against leishmaniasis is mediated mainly by CD4+ T lymphocytes, which function by secreting cytokines, which in turn activate various effector mechanisms. Interleukin 1 (IL-1) represents one of the most pleiotropic proinflammatory cytokines and is required for normal regulation of Th1/Th2 responses. The aim of this study was to induce the expression of the inflammatory cytokine IL-1alpha by Leishmania parasites and to determine its effect on the parasite development. Leishmania constitutively producing IL-1alpha was engineered, using the pX63Hyg-IL-1alpha vector. IL-1alpha was produced by both promastigotes and amastigotes, and remained unchanged after transformation and development in mice. The protection against the disease achieved in BALB/c mice by the transfected parasites was superior to that obtained with the wild type. One month after infection a nodule was demonstrated in 22% and 60% of the mice inoculated with transfected parasites and the wild type, respectively. This tendency continued for an additional 2.5 months, after which the rate of infection increased to 90% and 100% in these two groups, respectively. The present study suggests that, during initial infection, the pathway of IL-1alpha production and its accessibility to the immunological cells might be important in the outcome of leishmanial infection.

[Toxoplasma and toxoplasmosis].

Toxoplasmosis is a zoonotic protozoal disease, caused by an obligatory intracellular parasite of the genus Toxoplasma. The disease is widely distributed affecting more than a billion milliard people, worldwide. Raising sheep and cattle, handling and eating raw meat, interaction with domestic cats and climate conditions play an important role in the distribution of the disease. Both Toxoplasma and Plasmodium belong to the Phylum Apicomplexa, and are, therefore, almost similarly sensitive to anti-malarial drugs. Toxoplasmosis is considered to be viscerotropic in adults and children and neurotropic in fetal and newborn children. An accurate and fast diagnosis of the disease is highly important, particularly in pregnant women, since the results may affect both the mother and her fetus. The present study summarizes the old and new techniques available and their importance in the diagnosis of the disease.

Benzimidazole treatment of cystic echinococcosis.

Hydatidosis (cystic echinococcosis, CE) constitutes a serious public health problem worldwide. Total surgical removal of a hydatid cyst is still considered the gold standard treatment for CE. Percutaneous treatment (PAIR), using either hypertonic saline or alcohol as a larvacidal agent, appears to be an additional effective form of treatment. Benzimidazoles (albendazole, ABZ; mebendazole, MBZ), given either alone or combined with praziquantel (PZ) are currently used for the treatment of non-surgical cases and as a supplementary treatment prior and post-surgery. Combined chemotherapy was found to be more effective than either of the agents given alone. ABZ is easily absorbed and more effective than MBZ. ABZ (12-15 mg/kg/day) and MBZ (30-70 mg/kg/day) given for 14-20 days prior to surgery and continued for an additional 3-24 months in a cyclic monthly form were found effective against the disease. Either increased or decreased circulating antigen levels, which consequently cause changes in the humoral (IgG, IgG1, IgG4, IgE) immune responses, have a prognostic value in successfully treated CE cases. However, although the cellular immune response to echinococcal antigens decreased in improved or cured CE patients, it was not considered of practical use in determining treatment efficacy. In certain cases successful treatment was also followed by elevated eosinophilia and erythrocyte sedimentation rates. In the present article, the mechanism of drug activities as well as the development of resistance against the drugs available are further discussed.

Tropical treatment of new world cutaneous leishmaniasis in Belize: a clinical study

BACKGROUND: Many studies have been performed during the past decade to find an effective topical therapy for cutaneous leishmaniasis (CL). OBJECTIVE: Our purpose was to evaluate the effect of paromomycin ointment (P-ointment) containing 15 percent paromomycin sulfate and 12 percent methylbenzethonium chloride on Belizean patients with New World CL. METHODS: Fifty-three patients were treated twice daily for 14 to 21 days with P-ointment. RESULTS: Sixty-eight percent of the patients healed, 6 percent had a delayed cure, and 26 percent did not respond. No toxic effects from the ointment were observed. CONCLUSION: Topical paromomycin is as efficacious in the treatment of New World CL as other currently accepted modalities that are potentially more toxic (AU)