Anti-Leishmania amazonensis activity of the marine sponge Dercitus (Stoeba) latex (Porifera) from São Pedro and São Paulo Archipelago, Pernambuco, Brazil.

The search for new therapeutic strategies for leishmaniasis treatment is essential due to the side effects of available drugs and the increasing incidence of resistance to them. Marine sponges use chemical compounds as a defense mechanism, and several of them present interesting pharmacological properties. The aim of this study was to evaluate the in vitro activity of the aqueous extract of the marine sponge Dercitus (Stoeba) latex against Leishmania amazonensis. MIC and toxicity against mammal cells were evaluated through broth microdilution assays. Transmission electron microscopy analysis was performed to assess possible effects on L. amazonensis ultrastructure. Arginase and proteolytic activities were measured by spectrometric methodologies. The extract of Dercitus (Stoeba) latex displayed antileishmanial activity and moderate toxicity against peritonial macrophages. Ultrastructural changes were observed after the growth of L. amazonensis promastigotes in the presence of the extract at 150 µg.ml-1 (IC50), mainly on acidocalcysomes. The extract was able to inhibit the activity of arginase and serine proteases. This study shows that Dercitus (Stoeba) latex aqueous extract may be a novel potential source of protozoa protease inhibitors and drugs that are less toxic to be used in the treatment of L. amazonensis infections.

Histatin 5 and human lactoferrin inhibit biofilm formation of a fluconazole resistant Candida albicans clinical isolate.

Candida albicans is the most important fungal pathogen that causes infections in humans. Biofilms are hard-to-treat structures due to their high antifungal resistance. Saliva is a fluid that contains antimicrobial substances acting as the first-line of defense against pathogens, and its immune components may be potential tools for the discovery of new treatments against candidiasis. To evaluate the activity of histatin 5 and human lactoferrin against biofilm formation. A fluconazole-resistant Candida albicans clinical isolate was used as the model microorganism. Morphogenesis was evaluated by differential counting. Biofilm quantification was performed by XTT reduction assay. Thickness and topography of biofilms were assessed through confocal laser scanning microscopy (CLSM). Histatin 5 inhibited yeast-to-hyphae transition in a dose-dependent manner, while the effect of human lactoferrin on this process was inversely proportional to its concentration. Both compounds were able to significantly inhibit biofilm metabolic activity. Histatin 5 reduced biofilm thickness. Histatin 5 and human lactoferrin exhibited in vitro cytotoxicity against a fluconazole-resistant Candida albicans biofilm, which points to the potential application of these compounds in the treatment of biofilms formed by this fungus, especially in resistant infections.

Effect of serine-type protease of Candida spp. isolated from linear gingival erythema of HIV-positive children: critical factors in the colonization.

BACKGROUND: There are several kinds of oral soft tissue lesions that are common manifestations observed in human immunodeficiency virus (HIV)-infected children; for example, linear gingival erythema (LGE) that is a distinctive fiery red band along the margin of the gingivae. The etiology and pathogenesis of LGE are questionable, but a candidal origin has been suggested. Proteases are key virulence attributes produced by a variety of pathogenic fungi, including Candida. The objective of the present study is to identify the protease production in Candida species including, C. albicans (n=5), C. dubliniensis (n=1) and C. tropicalis (n=1), isolated directly from typical LGE lesions observed in six HIV-positive children, and also to test the effect of a serine protease inhibitor on the interaction of Candida spp. and epithelial cells in vitro. METHODS: The ability of Candida strains to release proteases in the culture supernatant fluids was visualized by gelatin-SDS-PAGE. Gel strips containing 30-fold concentrated supernatant (1.5×10(8) yeasts) were incubated at 37°C for 48 h in 50 mM sodium phosphate buffer, pH 5.5. The concentrated supernatants were also incubated with fibronectin, laminin, immunoglobulin G, bovine serum albumin and human serum albumin. The effect of serine protease inhibitor on the interaction of Candida spp. and epithelial cells (MA 104) was measured after pre-treatment of fungi with the inhibitor (phenylmethylsulphonyl fluoride, PMSF). RESULTS: All the extracellular proteases were completely inhibited by PMSF, identifying these activities as serine-type proteases. Interestingly, a common 62-kDa serine protease was observed in all Candida strains. The culture supernatants, rich in serine protease activities, cleaved several soluble proteinaceous substrates. Additionally, we demonstrated that pre-treatment of C. albicans, C. dubliniensis and C. tropicalis with PMSF diminished the interaction with epithelial cells. CONCLUSIONS: Collectively, our results show that Candida spp. isolated from LGE lesions produced and secreted serine proteases and these enzymes may be involved in the initial colonization events.

Resins-based denture soft lining materials modified by chlorhexidine salt incorporation: an in vitro analysis of antifungal activity, drug release and hardness.

OBJECTIVES: To evaluate the in vitro growth inhibition of Candida albicans, the rate of chlorhexidine release and shore A hardness from resins-based denture soft lining materials modified by chlorhexidine diacetate (CDA) or chlorhexidine hydrochloride (CHC) incorporation. METHODS: Resin discs were prepared from soft denture liners based on poly (methyl methacrylate) (PMMA) or poly (ethyl methacrylate) (PEMA) containing 0.5, 1.0 and 2.0 wt.% of CDA or CHC. For antifungal activity resin discs were placed on agar plates inoculated with C. albicans, after 48 h at 37°C the diameters of inhibition zones were measured. For the chlorhexidine release, discs were immersed into distilled water at 37°C, and spectral measurements were made after 48 h. Shore A hardness was evaluated at the baseline, 2 and 7 days, using 6mm thick rectangular specimens also immersed into distilled water at 37°C. Data were statistically processed by SigmaStat software using ANOVA and all pairwise multiple comparison procedures was done using the Holm-Sidak method, with α=0.05 (p<0.001). RESULTS: CDA added to PMMA soft liner and PEMA soft liner had a dose-related inhibitory effect on C. albicans and on chlorhexidine release rate (p<0.001). The PMMA and PEMA hardness increased statistically by time but not for the different CDA concentrations. CHC had no inhibitory effect on C. albicans. SIGNIFICANCE: Chlorhexidine diacetate released from resins-based soft lining materials can be convenient to reduce the biofilm development on the material surface and treat denture stomatitis, without depending on patient compliance.

Infecção pelo HIV em crianças e suas manifestações bucais: revisão de literatura / Pediatric HIV infection and its oral manifestations: a review

O conhecimento dos profissionais da área de Odontologia sobre a infecção pelo HIV e suas manifestações bucais, bem como a realização de uma correta anamnese e exame clínico são fatores muito importantes para o diagnóstico e tratamento precoce de crianças infectadas pelo HIV. O objetivo deste artigo é veicular as informações que irão contribuir para o enriquecimento teórico de clínicos e odontopediatras acerca deste assunto

Infecção pelo HIV em crianças e suas manifestações bucais: revisão de literatura / Pediatric HIV infection and its oral manifestations: a literature review

O conhecimento dos profissionais da área de Odontologia sobre a infecção pelo HIV e suas manifestações bucais, bem como a realização de uma correta anamnese e exame clínico, são fatores muito importantes para o diagnóstico e tratamento precoce de crianças infectadas pelo HIV. O objetivo deste artigo é veicular informações que irão contribuir para o enriquecimento teórico de clínicos e odontopediatras acerca do assunto