International journal of paediatric dentistry, Jan 4, 2018
Fungal infections are a serious problem among haemodialysis patients. The aims of this study were... more Fungal infections are a serious problem among haemodialysis patients. The aims of this study were to estimate the frequency of oral Candida species among children and adolescents undergoing haemodialysis (HD), to identify the isolated species, and to study the relationship between haemodialysis duration, amounts of colony-forming units, and salivary pH. A matched sample of 52 patients undergoing HD and 52 healthy individuals were selected. The samples were obtained from the dorsum of the tongue, and the colonies were identified through a substrate assimilation test. Stimulated whole saliva was collected from each patient for evaluation of salivary pH. The frequency of oral Candida species was 34.6% (18/52) and 46.20% (24/52) in the HD and control groups (P = 0.23), respectively. Candida parapsilosis complex was the most frequently isolated fungi species in the HD group (P = 0.03). A HD therapy duration of more than 1 year was statistically correlated with a higher number of colony-f...
The effects of platelet-activating factor (PAF) on the infection of peritoneal mouse macrophages ... more The effects of platelet-activating factor (PAF) on the infection of peritoneal mouse macrophages by Leishmania amazonensis were investigated. Prior to the infection, the parasites and/or the macrophages were treated with PAF and/or one of the following modulators: WEB 2086 (PAF antagonist), and the modulators of protein kinase C, phorbol-12-myristate-13-acetate (PMA), and sphingosine. The infection was inhibited when the macrophages or both the parasites and the macrophages were treated with PAF, but stimulated by PAF-treated parasites. WEB 2086 abrogated PAF effects in both systems. The infection was stimulated when the macrophages were treated with sphingosine plus PAF, but inhibited when the macrophages were treated with sphingosine and the parasites with sphingosine plus PAF. The infection was inhibited by sphingosine-treated parasites, either in the presence or in the absence of PAF. Leishmania amazonensis-macrophage infection was inhibited by PMA in all systems tested.
Candida glabrata ranks second in epidemiological surveillance studies, and is considered one of t... more Candida glabrata ranks second in epidemiological surveillance studies, and is considered one of the main human yeast pathogens. Treatment of Candida infections represents a contemporary public health problem due to the limited availability of an antifungal arsenal, toxicity effects and increasing cases of resistance. C. glabrata presents intrinsic fluconazole resistance and is a significant concern in clinical practice and in hospital environments. The aim of this study was to characterise the azole resistance mechanism presented by a C. glabrata clinical isolate from a Brazilian university hospital. Azole susceptibility assays, chemosensitisation, flow cytometry and mass spectrometry were performed. Our study demonstrated extremely high resistance to all azoles tested: fluconazole, voriconazole, posaconazole and itraconazole. This isolate was chemosensitised by FK506, a classical inhibitor of ABC transporters related to azole resistance, and Rhodamine 6G extrusion was observed. A m...
Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. ... more Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis.
Anais da Academia Brasileira de Ciencias, Jan 11, 2017
Casearia genus (Salicaceae) is found in sub-tropical and tropical regions of the world and compri... more Casearia genus (Salicaceae) is found in sub-tropical and tropical regions of the world and comprises about 160-200 species. It is a medicinal plant used in South America, also known as "guaçatonga", "erva-de-tiú", "cafezinho-do-mato". In Brazil, there are about 48 species and 12 are registered in the State of Rio de Janeiro, including Casearia sylvestris Sw. There are many studies related to the chemical profile and cytotoxic activities of extracts from these plants, although few studies about the antifungal potential of the essential oil have been reported. In this work, we have studied the antifungal properties of the essential oil of C. sylvestris leaves, as well as of their fractions, against four yeasts (Saccharomyces cerevisae, Candida albicans, C. glabrata and C. krusei) for the first time. The chemical analysis of the essential oil revealed a very diversified (n = 21 compounds) volatile fraction composed mainly of non-oxygenated sesquiterpenes (...
Visceral leishmaniasis is a neglected disease caused by Leishmania protozoa parasites transmitted... more Visceral leishmaniasis is a neglected disease caused by Leishmania protozoa parasites transmitted by infected sand fly vectors. This disease represents the second in mortality among tropical infections and is associated to a profound immunosuppression state of the host. The hallmark of this infection-induced host immunodeviation is the characteristic high levels of the regulatory interleukin-10 (IL-10) cytokine. In the present study, we investigated the role of B-1 cells in the maintenance of splenic IL-10 levels that could interfere with resistance to parasite infection. Using an experimental murine infection model with Leishmania (L.) infantum chagasi we demonstrated an improved resistance of B-1 deficient BALB/XID mice to infection. BALB/XID mice developed a reduced splenomegaly with diminished splenic parasite burden and lower levels of IL-10 secretion of purified splenocytes at 30 days post-infection, as compared to BALB/c wild-type control mice. Interestingly, we found that resident peritoneal macrophages isolated from BALB/XID mice were more effective to control the parasite load in comparison to cells isolated from BALB/c wild-type mice. Our findings point to a role of B-1 cells in the host susceptibility to visceral leishmaniasis.
Calcineurin inhibitors - such as the clinically used drug tacrolimus - are active against importa... more Calcineurin inhibitors - such as the clinically used drug tacrolimus - are active against important fungal pathogens, particularly when combined with azoles. However, tacrolimus has not been tested against sporotrichosis, an endemic subcutaneous mycosis with worldwide distribution. Here, we evaluated the activity of tacrolimus and cyclosporine A in vitro - as monotherapy and in combination with itraconazole or fluconazole - against yeasts of Sporothrix brasiliensis and S. schenckii, the main sporotrichosis agents in Brazil. We also analyzed the effect of tacrolimus treatment on intracellular neutral lipid levels, which typically increase after azole treatment. Tacrolimus inhibited the growth of yeasts from S. brasiliensis and S. schenckii reference isolates, with minimum inhibitory concentration (MIC) values (required for ≥50% growth inhibition) of 1 and 2 mg/L, respectively. Importantly, the combination of tacrolimus and azoles exhibited high synergy toward reference Sporothrix isolates. Tacrolimus combined with itraconazole significantly increased neutral lipid accumulation in S. brasiliensis, but not in S. schenckii. Clinical isolates of S. brasiliensis and S. schenckii were more sensitive to tacrolimus as monotherapy than feline-borne isolates, however, synergy between tacrolimus and azoles was only observed for feline-borne isolates. Cyclosporine A was effective against S. brasiliensis and S. schenckii as monotherapy (MIC = 1 mg/L), but exhibited no synergy with itraconazole and fluconazole. We conclude that tacrolimus has promising antifungal activity against sporotrichosis agents, and also increases the activity of the current anti-sporotrichosis therapy (itraconazole and fluconazole) in combination assays against S. brasiliensis feline-borne isolates.
Candidaemia is a public health problem mainly in hospitalized individuals worldwide. In Brazil, C... more Candidaemia is a public health problem mainly in hospitalized individuals worldwide. In Brazil, Candida albicans is the most prevalent species that causes candidaemia, followed by Candida tropicalis and Candida parapsilosis . Few data on the abundance of antifungal resistance are available for Latin America. We analysed the frequency of azole and echinocandin resistance in Candida isolates ( n = 75) collected between 2012 and 2014 at the University Hospital of Federal University of Juiz de Fora (Brazil). The primary targets erg11 (azoles) and fks1 (echinocandins) were sequenced and modelled at the protein level. Antifungal susceptibility testing was performed according to CLSI (M27-A3 and M27-S4) and according to EUCAST. The three most frequent species were C. albicans (38.0%), C. tropicalis (30.0%) and Candida glabrata (17.0%). Azole resistance was observed in 27.0% of all Candida isolates, while 20.0% of all isolates were echinocandin resistant. A novel mutation in erg11 at location K143R was found to be associated with phenotypically pan-azole-resistant C. tropicalis isolates. This mutation maps near the active binding site of erg11 and is likely to confer pan-azole resistance to C. tropicalis . A novel point mutation (K143R) located in the erg11 gene of C. tropicalis was found in pan-azole-resistant strains. According to our protein homology model, it is very likely that the mutation K143R causes pan-azole resistance in C. tropicalis . Moreover, an up-regulation of ABC transporters was observed, which can add up to a pan-azole-resistant phenotype.
Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. ... more Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis.
Candidiasis has become an important concern for clinical practice, especially with the increasing... more Candidiasis has become an important concern for clinical practice, especially with the increasing incidence of immunocompromised patients. In this scenario, the development resistance to fluconazole presents a challenge for treating these opportunistic infections. The aim of this study was to evaluate some epidemiology features of Candidainfections in a Brazilian University Hospital using data, previously unavailable. We observed that 44% of the 93 clinical isolates tested, belonged to Candida albicansspecies and 56% belonged to non-Candida albicansspecies (mainly Candida tropicalis and Candida glabrata). Most strains were isolated from urine samples where C. albicans was predominantly detected. 29 strains presented a fluconazole resistance phenotype and of these, 22 were chemosensitised by FK506, a classical inhibitor of ABC transporters related to azoles resistance. These data suggest the probable role of efflux pumps in this resistance phenotype. Our study highlights the need for...
Candidiasis has become an important concern for clinical practice, especially with the increasing... more Candidiasis has become an important concern for clinical practice, especially with the increasing incidence of immunocompromised patients. In this scenario, the development resistance to fluconazole presents a challenge for treating these opportunistic infections. The aim of this study was to evaluate some epidemiology features of Candidainfections in a Brazilian University Hospital using data, previously unavailable. We observed that 44% of the 93 clinical isolates tested, belonged to Candida albicansspecies and 56% belonged to non-Candida albicansspecies (mainly Candida tropicalis and Candida glabrata). Most strains were isolated from urine samples where C. albicans was predominantly detected. 29 strains presented a fluconazole resistance phenotype and of these, 22 were chemosensitised by FK506, a classical inhibitor of ABC transporters related to azoles resistance. These data suggest the probable role of efflux pumps in this resistance phenotype. Our study highlights the need for...
Este livro é o resultado das atividades de ensino dos autores na Universidade Federal do Rio de J... more Este livro é o resultado das atividades de ensino dos autores na Universidade Federal do Rio de Janeiro, no Instituto de Microbiologia Prof. Paulo de Góes, no Departamento de Microbiologia Geral. Reúne as aulas práticas de Microbiologia que formam o curso básico que é oferecido a todos os alunos da área de Ciências da Saúde. Estas práticas são fundamentais para a compreensão da Microbiologia e englobam a apresentação dos materiais e técnicas básicas usados em Microbiologia, o treinamento de manobras assépticas e os métodos físicos e químicos de controle do crescimento microbiano. Microscopia de microrganismos com exames a fresco e com colorações diferenciais, técnicas de isolamento e contagem de microrganismos, obtenção de cultura pura, provas bioquímicas usadas na identificação de microrganismos e antibiogramas também são abordadas. Esses assuntos estão agrupados em 7 capítulos, incluindo os fundamentos teóricos específicos de cada prática.
The H(+)-ATPase from Schizosaccharomyces pombe belongs to the group of transport ATPases which di... more The H(+)-ATPase from Schizosaccharomyces pombe belongs to the group of transport ATPases which displays two main conformational states, E1 and E2 (P-type ATPase). In this report, we show that, as in the case of other P-type ATPase, the purified enzyme exhibits a p-nitrophenylphosphatase activity which can be completely inhibited by vanadate. In aqueous medium, p-nitrophenyl phosphate hydrolysis proceeds at only 0.5% of the rate of ATP hydrolysis, and both activities can be stimulated 3- to 4-fold by decreasing the pH from 7.5 to 6.5. Addition of the organic solvent dimethyl sulfoxide (10-40%), which has been shown to favor the E2 conformation, stimulates the p-nitrophenylphosphatase activity but inhibits the ATPase activity. At pH 7.5, the Km for p-nitrophenyl phosphate decreases when dimethyl sulfoxide is present. In the presence of 30% (v/v) dimethyl sulfoxide, the phosphatase activity can be inhibited by ATP (K(i) 300 microM) or by P(i) (K(i) 1 mM). The H(+)-ATPase incorporated i...
The aims of this study were to investigate the caries experience, periodontal status, oral hygien... more The aims of this study were to investigate the caries experience, periodontal status, oral hygiene habits, and salivary parameters of children and adolescents undergoing hemodialysis (HD) and to compare them with their healthy counterparts. Fifty-two HD patients were matched for age, sex, ethnicity, and social class with 52 healthy subjects for analysis of the number of decayed, missing and filled teeth, plaque and gingival index, dental calculus accumulation, measurements of pocket depth, clinical attachment level, gingival recession, and bleeding on probing. Stimulated saliva samples were collected to assess salivary flow rate, pH and buffer capacity, and salivary concentrations of calcium, phosphate, and urea by colorimetric method. HD patients had lower dental caries (p = 0.004), greater plaque and calculus accumulation (p = 0.001), and reported flossing less often than the controls (p = 0.013). Regarding salivary analysis, HD patients showed significantly higher values of pH, buffer capacity, and salivary urea concentration when compared to the controls (p = 0.001). HD patients had lower caries experience, higher accumulation of dental plaque, and calculus deposition than their healthy counterparts, probably due to the differences found in their salivary biochemical parameters. A significant number of children and adolescents undergoing hemodialysis are candidates for kidney transplantation and should receive complete pre-transplant dental exams and dental treatment. Our results open the way for the development of an individualized dental protocol for these patients with preventive measures and treatment of the poor oral health in HD patients.
In the current study, we tested the effect of 27 plant extracts and fractions from different bota... more In the current study, we tested the effect of 27 plant extracts and fractions from different botanical families on the activity of Pdr5p from yeast plasma membrane, responsible for the multidrug resistance phenotype in yeast cells. Some of the extracts were able to produce a ...
International journal of paediatric dentistry, Jan 4, 2018
Fungal infections are a serious problem among haemodialysis patients. The aims of this study were... more Fungal infections are a serious problem among haemodialysis patients. The aims of this study were to estimate the frequency of oral Candida species among children and adolescents undergoing haemodialysis (HD), to identify the isolated species, and to study the relationship between haemodialysis duration, amounts of colony-forming units, and salivary pH. A matched sample of 52 patients undergoing HD and 52 healthy individuals were selected. The samples were obtained from the dorsum of the tongue, and the colonies were identified through a substrate assimilation test. Stimulated whole saliva was collected from each patient for evaluation of salivary pH. The frequency of oral Candida species was 34.6% (18/52) and 46.20% (24/52) in the HD and control groups (P = 0.23), respectively. Candida parapsilosis complex was the most frequently isolated fungi species in the HD group (P = 0.03). A HD therapy duration of more than 1 year was statistically correlated with a higher number of colony-f...
The effects of platelet-activating factor (PAF) on the infection of peritoneal mouse macrophages ... more The effects of platelet-activating factor (PAF) on the infection of peritoneal mouse macrophages by Leishmania amazonensis were investigated. Prior to the infection, the parasites and/or the macrophages were treated with PAF and/or one of the following modulators: WEB 2086 (PAF antagonist), and the modulators of protein kinase C, phorbol-12-myristate-13-acetate (PMA), and sphingosine. The infection was inhibited when the macrophages or both the parasites and the macrophages were treated with PAF, but stimulated by PAF-treated parasites. WEB 2086 abrogated PAF effects in both systems. The infection was stimulated when the macrophages were treated with sphingosine plus PAF, but inhibited when the macrophages were treated with sphingosine and the parasites with sphingosine plus PAF. The infection was inhibited by sphingosine-treated parasites, either in the presence or in the absence of PAF. Leishmania amazonensis-macrophage infection was inhibited by PMA in all systems tested.
Candida glabrata ranks second in epidemiological surveillance studies, and is considered one of t... more Candida glabrata ranks second in epidemiological surveillance studies, and is considered one of the main human yeast pathogens. Treatment of Candida infections represents a contemporary public health problem due to the limited availability of an antifungal arsenal, toxicity effects and increasing cases of resistance. C. glabrata presents intrinsic fluconazole resistance and is a significant concern in clinical practice and in hospital environments. The aim of this study was to characterise the azole resistance mechanism presented by a C. glabrata clinical isolate from a Brazilian university hospital. Azole susceptibility assays, chemosensitisation, flow cytometry and mass spectrometry were performed. Our study demonstrated extremely high resistance to all azoles tested: fluconazole, voriconazole, posaconazole and itraconazole. This isolate was chemosensitised by FK506, a classical inhibitor of ABC transporters related to azole resistance, and Rhodamine 6G extrusion was observed. A m...
Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. ... more Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis.
Anais da Academia Brasileira de Ciencias, Jan 11, 2017
Casearia genus (Salicaceae) is found in sub-tropical and tropical regions of the world and compri... more Casearia genus (Salicaceae) is found in sub-tropical and tropical regions of the world and comprises about 160-200 species. It is a medicinal plant used in South America, also known as "guaçatonga", "erva-de-tiú", "cafezinho-do-mato". In Brazil, there are about 48 species and 12 are registered in the State of Rio de Janeiro, including Casearia sylvestris Sw. There are many studies related to the chemical profile and cytotoxic activities of extracts from these plants, although few studies about the antifungal potential of the essential oil have been reported. In this work, we have studied the antifungal properties of the essential oil of C. sylvestris leaves, as well as of their fractions, against four yeasts (Saccharomyces cerevisae, Candida albicans, C. glabrata and C. krusei) for the first time. The chemical analysis of the essential oil revealed a very diversified (n = 21 compounds) volatile fraction composed mainly of non-oxygenated sesquiterpenes (...
Visceral leishmaniasis is a neglected disease caused by Leishmania protozoa parasites transmitted... more Visceral leishmaniasis is a neglected disease caused by Leishmania protozoa parasites transmitted by infected sand fly vectors. This disease represents the second in mortality among tropical infections and is associated to a profound immunosuppression state of the host. The hallmark of this infection-induced host immunodeviation is the characteristic high levels of the regulatory interleukin-10 (IL-10) cytokine. In the present study, we investigated the role of B-1 cells in the maintenance of splenic IL-10 levels that could interfere with resistance to parasite infection. Using an experimental murine infection model with Leishmania (L.) infantum chagasi we demonstrated an improved resistance of B-1 deficient BALB/XID mice to infection. BALB/XID mice developed a reduced splenomegaly with diminished splenic parasite burden and lower levels of IL-10 secretion of purified splenocytes at 30 days post-infection, as compared to BALB/c wild-type control mice. Interestingly, we found that resident peritoneal macrophages isolated from BALB/XID mice were more effective to control the parasite load in comparison to cells isolated from BALB/c wild-type mice. Our findings point to a role of B-1 cells in the host susceptibility to visceral leishmaniasis.
Calcineurin inhibitors - such as the clinically used drug tacrolimus - are active against importa... more Calcineurin inhibitors - such as the clinically used drug tacrolimus - are active against important fungal pathogens, particularly when combined with azoles. However, tacrolimus has not been tested against sporotrichosis, an endemic subcutaneous mycosis with worldwide distribution. Here, we evaluated the activity of tacrolimus and cyclosporine A in vitro - as monotherapy and in combination with itraconazole or fluconazole - against yeasts of Sporothrix brasiliensis and S. schenckii, the main sporotrichosis agents in Brazil. We also analyzed the effect of tacrolimus treatment on intracellular neutral lipid levels, which typically increase after azole treatment. Tacrolimus inhibited the growth of yeasts from S. brasiliensis and S. schenckii reference isolates, with minimum inhibitory concentration (MIC) values (required for ≥50% growth inhibition) of 1 and 2 mg/L, respectively. Importantly, the combination of tacrolimus and azoles exhibited high synergy toward reference Sporothrix isolates. Tacrolimus combined with itraconazole significantly increased neutral lipid accumulation in S. brasiliensis, but not in S. schenckii. Clinical isolates of S. brasiliensis and S. schenckii were more sensitive to tacrolimus as monotherapy than feline-borne isolates, however, synergy between tacrolimus and azoles was only observed for feline-borne isolates. Cyclosporine A was effective against S. brasiliensis and S. schenckii as monotherapy (MIC = 1 mg/L), but exhibited no synergy with itraconazole and fluconazole. We conclude that tacrolimus has promising antifungal activity against sporotrichosis agents, and also increases the activity of the current anti-sporotrichosis therapy (itraconazole and fluconazole) in combination assays against S. brasiliensis feline-borne isolates.
Candidaemia is a public health problem mainly in hospitalized individuals worldwide. In Brazil, C... more Candidaemia is a public health problem mainly in hospitalized individuals worldwide. In Brazil, Candida albicans is the most prevalent species that causes candidaemia, followed by Candida tropicalis and Candida parapsilosis . Few data on the abundance of antifungal resistance are available for Latin America. We analysed the frequency of azole and echinocandin resistance in Candida isolates ( n = 75) collected between 2012 and 2014 at the University Hospital of Federal University of Juiz de Fora (Brazil). The primary targets erg11 (azoles) and fks1 (echinocandins) were sequenced and modelled at the protein level. Antifungal susceptibility testing was performed according to CLSI (M27-A3 and M27-S4) and according to EUCAST. The three most frequent species were C. albicans (38.0%), C. tropicalis (30.0%) and Candida glabrata (17.0%). Azole resistance was observed in 27.0% of all Candida isolates, while 20.0% of all isolates were echinocandin resistant. A novel mutation in erg11 at location K143R was found to be associated with phenotypically pan-azole-resistant C. tropicalis isolates. This mutation maps near the active binding site of erg11 and is likely to confer pan-azole resistance to C. tropicalis . A novel point mutation (K143R) located in the erg11 gene of C. tropicalis was found in pan-azole-resistant strains. According to our protein homology model, it is very likely that the mutation K143R causes pan-azole resistance in C. tropicalis . Moreover, an up-regulation of ABC transporters was observed, which can add up to a pan-azole-resistant phenotype.
Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. ... more Leishmania (Leishmania) infantum chagasi is one of the agents that cause visceral leishmaniasis. This disease occurs more frequently in third world countries, such as Brazil. The treatment is arduous, and is dependent on just a few drugs like the antimonial derivatives and amphotericin B. Moreover, these drugs are not only expensive, but they can also cause severe side effects and require long-term treatment. Therefore, it is very important to find new compounds that are effective against leishmaniasis. In the present work we evaluated a new group of synthetic amides against the promastigote and amastigote forms of L. infantum chagasi. The results showed that one of these amides in particular, presented very effective activity against the promastigotes and amastigotes of L. infantum chagasi at low concentrations and it also presented low toxicity for mammal cells, which makes this synthetic amide a promising drug for combating leishmaniasis.
Candidiasis has become an important concern for clinical practice, especially with the increasing... more Candidiasis has become an important concern for clinical practice, especially with the increasing incidence of immunocompromised patients. In this scenario, the development resistance to fluconazole presents a challenge for treating these opportunistic infections. The aim of this study was to evaluate some epidemiology features of Candidainfections in a Brazilian University Hospital using data, previously unavailable. We observed that 44% of the 93 clinical isolates tested, belonged to Candida albicansspecies and 56% belonged to non-Candida albicansspecies (mainly Candida tropicalis and Candida glabrata). Most strains were isolated from urine samples where C. albicans was predominantly detected. 29 strains presented a fluconazole resistance phenotype and of these, 22 were chemosensitised by FK506, a classical inhibitor of ABC transporters related to azoles resistance. These data suggest the probable role of efflux pumps in this resistance phenotype. Our study highlights the need for...
Candidiasis has become an important concern for clinical practice, especially with the increasing... more Candidiasis has become an important concern for clinical practice, especially with the increasing incidence of immunocompromised patients. In this scenario, the development resistance to fluconazole presents a challenge for treating these opportunistic infections. The aim of this study was to evaluate some epidemiology features of Candidainfections in a Brazilian University Hospital using data, previously unavailable. We observed that 44% of the 93 clinical isolates tested, belonged to Candida albicansspecies and 56% belonged to non-Candida albicansspecies (mainly Candida tropicalis and Candida glabrata). Most strains were isolated from urine samples where C. albicans was predominantly detected. 29 strains presented a fluconazole resistance phenotype and of these, 22 were chemosensitised by FK506, a classical inhibitor of ABC transporters related to azoles resistance. These data suggest the probable role of efflux pumps in this resistance phenotype. Our study highlights the need for...
Este livro é o resultado das atividades de ensino dos autores na Universidade Federal do Rio de J... more Este livro é o resultado das atividades de ensino dos autores na Universidade Federal do Rio de Janeiro, no Instituto de Microbiologia Prof. Paulo de Góes, no Departamento de Microbiologia Geral. Reúne as aulas práticas de Microbiologia que formam o curso básico que é oferecido a todos os alunos da área de Ciências da Saúde. Estas práticas são fundamentais para a compreensão da Microbiologia e englobam a apresentação dos materiais e técnicas básicas usados em Microbiologia, o treinamento de manobras assépticas e os métodos físicos e químicos de controle do crescimento microbiano. Microscopia de microrganismos com exames a fresco e com colorações diferenciais, técnicas de isolamento e contagem de microrganismos, obtenção de cultura pura, provas bioquímicas usadas na identificação de microrganismos e antibiogramas também são abordadas. Esses assuntos estão agrupados em 7 capítulos, incluindo os fundamentos teóricos específicos de cada prática.
The H(+)-ATPase from Schizosaccharomyces pombe belongs to the group of transport ATPases which di... more The H(+)-ATPase from Schizosaccharomyces pombe belongs to the group of transport ATPases which displays two main conformational states, E1 and E2 (P-type ATPase). In this report, we show that, as in the case of other P-type ATPase, the purified enzyme exhibits a p-nitrophenylphosphatase activity which can be completely inhibited by vanadate. In aqueous medium, p-nitrophenyl phosphate hydrolysis proceeds at only 0.5% of the rate of ATP hydrolysis, and both activities can be stimulated 3- to 4-fold by decreasing the pH from 7.5 to 6.5. Addition of the organic solvent dimethyl sulfoxide (10-40%), which has been shown to favor the E2 conformation, stimulates the p-nitrophenylphosphatase activity but inhibits the ATPase activity. At pH 7.5, the Km for p-nitrophenyl phosphate decreases when dimethyl sulfoxide is present. In the presence of 30% (v/v) dimethyl sulfoxide, the phosphatase activity can be inhibited by ATP (K(i) 300 microM) or by P(i) (K(i) 1 mM). The H(+)-ATPase incorporated i...
The aims of this study were to investigate the caries experience, periodontal status, oral hygien... more The aims of this study were to investigate the caries experience, periodontal status, oral hygiene habits, and salivary parameters of children and adolescents undergoing hemodialysis (HD) and to compare them with their healthy counterparts. Fifty-two HD patients were matched for age, sex, ethnicity, and social class with 52 healthy subjects for analysis of the number of decayed, missing and filled teeth, plaque and gingival index, dental calculus accumulation, measurements of pocket depth, clinical attachment level, gingival recession, and bleeding on probing. Stimulated saliva samples were collected to assess salivary flow rate, pH and buffer capacity, and salivary concentrations of calcium, phosphate, and urea by colorimetric method. HD patients had lower dental caries (p = 0.004), greater plaque and calculus accumulation (p = 0.001), and reported flossing less often than the controls (p = 0.013). Regarding salivary analysis, HD patients showed significantly higher values of pH, buffer capacity, and salivary urea concentration when compared to the controls (p = 0.001). HD patients had lower caries experience, higher accumulation of dental plaque, and calculus deposition than their healthy counterparts, probably due to the differences found in their salivary biochemical parameters. A significant number of children and adolescents undergoing hemodialysis are candidates for kidney transplantation and should receive complete pre-transplant dental exams and dental treatment. Our results open the way for the development of an individualized dental protocol for these patients with preventive measures and treatment of the poor oral health in HD patients.
In the current study, we tested the effect of 27 plant extracts and fractions from different bota... more In the current study, we tested the effect of 27 plant extracts and fractions from different botanical families on the activity of Pdr5p from yeast plasma membrane, responsible for the multidrug resistance phenotype in yeast cells. Some of the extracts were able to produce a ...
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