Carlos Eduardo Blanco Linares

Enzymatic and hemolytic activities of Candida dubliniensis strains

Candida dubliniensis is an opportunistic yeast that has been recovered from several body sites in many populations; it is most often recovered from the oral cavities of human immunodeficiency virus-infected patients. Although extensive studies on epidemiology and phylogeny of C. dubliniensis have been performed, little is known about virulence factors such as exoenzymatic and hemolytic activities. In this study we compared proteinase, hyaluronidase, chondroitin sulphatase and hemolytic activities in 18 C. dubliniensis and 30 C. albicans strains isolated from AIDS patients. C. albicans isolates produced higher amounts of proteinase than C. dubliniensis (p < 0.05). All the tested C. dubliniensis strains expressed hyaluronidase and chondroitin sulphatase activities, but none of them were significantly different from those observed with C. albicans (p > 0.05). Hemolytic activity was affected by CaCl2; when this component was absent, we did not notice any significant difference between C. albicans and C. dubliniensis hemolytic activities. On the contrary, when we added 2.5 g% CaCl2, the hemolytic activity was reduced on C. dubliniensis and stimulated on C. albicans tested strains (p < 0.05).

Comparison among tomato juice agar with other three media for differentiation of Candida dubliniensis from Candida albicans

The purpose of the present study is to compare the tomato juice agar, a well known medium employed to observe ascospore formation, with niger seed agar, casein agar and sunflower seed agar, applied to a differentiation between C. dubliniensis and C. albicans. After 48 hours of incubation at 30 degrees C all 26 (100%) C. dubliniensis isolates tested produced chlamydospores on tomato juice agar as well as in the other three media evaluated. However, when we inoculated all media with C. albicans, the absence of chlamydospores became resulting in the following percents: tomato juice agar (92.47%), niger seed agar (96.7%), casein agar (91.39%), and sunflower seed agar (96.7%). These results indicate that tomato juice agar is another medium which can also be used in the first phenotypic differentiation between C. dubliniensis and C. albicans.

CHIRAL ANALYSIS OF MONOTERPENES IN VOLATILE OILS FROM PROPOLIS

The essential oils obtained by hydrodistillation from samples of propolis manufactured in three regions of Rio Grande do Sul State at Brazil, were analyzed through CG, CG-MS and chiral phase gas chromatography (CPGC). These analyses display the presence of samples with elevated essential oil purport, when compared with plants. The yields obtained were until 3.8%. The samples exhibited similar composition, with predominance of the monoterpenes a-pinene (5763%), b-pinene (12.5-30.8%) and limonene (1.5-11.2%). In chiral analysis of these constituents were observed modifications in the enantiomeric excess of isomers of a-pinene and limonene in relation with source location of the sample, already in the chiral analysis of b-pinene were detected only elevated excess of the enantiomer with the (-) configuration. The antimicrobial activity of the crude essential oil was assayed against five bacteria. The best result was obtained against Staphylococcus aureus.

Utilização do ágar suco de tomate (ágar V8) na identificação presuntiva de Candida dubliniensis

We evaluated the capacity of tomato juice agar (V8 agar) to differentiate Candida dubliniensis from Candida albicans based on chlamydospore production. Candida albicans (n= 93) and Candida dubliniensis (n= 26) were studied; 100% of Candida dubliniensis showed chlamydospores and in 92.5% of Candida albicans isolates these elements were absent. These results suggest this medium as an alternative tool for presumptive differentiation between these species.

Different culture media applied to the study of Cryptococcus neoformans susceptibility to amphotericin B and fluconazole

This study compared the performance of three culture media used for the determination of minimal inhibitory concentration (MIC) of amphotericin B and fluconazole against 48 Cryptococcus neoformans strains. For amphotericin B the media employed were RPMI 1640 medium, as indicated by NCCLS as reference, Yeast Nitrogen Base (YNB) as proposed by Ghannoum et al. (YNB-1), Antibiotic medium 3 (AM3) indicated by others, and YNB as proposed by us (YNB-2). In YNB-1, amphotericin B showed broader MIC ranges, varying from 0.125 µg/ml to 1.0 µg/ml; in RPMI 1640 medium and YNB-2 the MICs were similar and in AM3 the MIC ranges were narrower. The same pattern was observed for MIC 90%. For fluconazole the media employed were RPMI 1640 and YNB-1. The MIC ranges were broader and elevated when YNB-1 was employed. MIC 50% were 2.0 µg/ml in RPMI 1640 medium and 4.0 µg/ml in YNB-1. Our results indicate that RPMI 1640 supplemented with 2% glucose allowed a good growth at 48h; YNB as recommended by Ghannoum et al. provided a broader MIC range, AM3 provided a narrow MIC range for amphotericin B, and YNB-2 was very similar to RPMI 1640 medium.

ESTUDO EPIDEMIOLÓGICO E PERFIL DA SUSCETIBILIDADE DE AMOSTRAS DE CANDIDA ISOLADAS DE MULHERES COM CANDIDIASE VULVOVAGINAL EM FREDERICO WESTPHALEN – RS

As infeccoes causadas por Candida sao micoses oportunistas reconhecidas desde o seculo V a.C.O genero Candida e caracterizado como fungo leveduriforme, saprofita e oportunista, que sob determinadas condicoes multiplica-se, tornando-se patogenico. Celulas de Candida sao encontradas navagina em 20% de mulheres sadias e assintomaticas. A candidiase vaginal ocorre, principalmente,nas mulheres que estao entre a puberdade e a menopausa, sugerindo dependencia hormonal nainfeccao. No periodo de agosto de 2004 a junho de 2005 foram realizadas coletas de amostras desecrecoes vaginais de mulheres com sintomatologia de infeccao vulvovaginal atendidas em tresestabelecimentos de saude de Frederico Westphalen – RS. As amostras positivas foram identificadase a sensibilidade frente os antifungicos fluconazol e anfotericina B foi avaliada. Os resultados obtidos demonstram que Candida spp. ocupou o quarto lugar dentre todas as especies isoladas causando infeccoes vulvovaginais, sendo que a identificacao apontou Candida albicans como especiemais prevalentemente isolada. Os testes de suscetibilidade revelaram que Candida glabrata foimais sensivel do que Candida albicans e Candida tropicalis a anfotericina B. Frente ao fluconazolCandida albicans e Candida tropicalis foram consideradas sensiveis. De acordo com as normas doNCCLS os isolados foram considerados sensiveis a anfotericina B e fluconazol.

NÍVEIS BASAIS DE ACETILCOLINESTERASE E BUTIRILCOLINESTERASE EM AGRICULTORES DA REGIÃO DE FREDERICO WESTPHALEN – RS

A elevada utilizacao de agrotoxicos, sem os devidos cuidados, tem contribuido em muito para oaumento das intoxicacoes ocupacionais, sendo hoje, um dos principais problemas de saude publica no meio rural brasileiro. Entre os pesticidas mais utilizados estao os compostos pertencentes acategoria dos organofosforados que sao inibidores da acetilcolinesterase e butirilcolinesterase comvariado grau de toxicidade em seres humanos. Intoxicacoes por esses compostos podem acarretardiversas alteracoes sendo a principal e de maior risco ao homem a alteracao neuropsicologica. Osdados referentes a utilizacao de compostos dessa categoria ainda sao uma realidade extra-oficial;todavia, motivaram a realizacao deste estudo. Neste contexto, o objetivo deste trabalho foi avaliar aexposicao dos agricultores da area rural de Frederico Westphalen – RS a agrotoxicos inibidores dascolinesterases, valendo-se de dados nao oficiais quanto ao uso indiscriminado de organofosforadosnessa regiao. As atividades enzimaticas foram avaliadas segundo metodo de Ellman (1961) modificado. Apos a determinacao individual das atividades da butirilcolinesterase plasmaticas eacetilcolinesterase eritrocitaria de 60 agricultores, verificou-se que 15 (25%) agricultores apresentaram valores de butirilcolinesterase abaixo dos valores de referencia obtidos para o grupo controle, aopasso que, todos os agricultores apresentaram valores de acetilcolinesterase inferiores aos valoresde referencia. Estes resultados sao indicadores seguros de uma exposicao e/ou intoxicacao porpesticidas inibidores de colinesterases.