Efeito da incorporação de agentes antifúngicos na resistência à tração e porosidade de materiais resilientes temporários para base de próteses / Effect of incorporation of antifungal agents on the ultimate tensile strength and porosity of temporary soft denture liners

Este estudo investigou a resistência à tração (ou limite de resistência à tração- LRT) e a porosidade de reembasadores resilientes temporários modificados por concentrações inibitórias mínimas (CIMs) de agentes antifúngicos para o biofilme Candida albicans (SC5314). Para os testes de LRT, corpos de prova em forma de halteres (n=7) com uma área transversal de 33 mm x 6 mm x 3 mm foram produzidos para os materiais resilientes (Trusoft e Softone) sem (controle) ou com incorporação de cinco fármacos em suas CIMs: nistatina- 0,032 g; diacetato de clorexidina- 0,064; cetoconazol- 0,128 g; miconazol- 0,256 g; itraconazol-0,256 g (grama de fármaco por grama de pó de material resiliente). Após a plastificação, as amostras foram imersas em água destilada a 37°C durante 24 h, 7 e 14 dias e, então, testadas em tensão em uma máquina universal de ensaios (EMIC DL-500 MF) a 40 mm/min. A porosidade foi mensurada por absorção de água, com base na exclusão do efeito plastificante. Inicialmente, determinou-se por isotermas de sorção, que a solução de armazenagem adequada para os corpos de prova (65 mm x 10 mm x 3,3 mm) de ambos os materiais foi o cloreto de cálcio anidro a 50% (S50). Assim, o fator de porosidade (FP) foi calculado para os grupos de estudo (n=10) formados por espécimes sem (controle) ou com incorporação de fármaco em suas CIMs (nistatina, clorexidina ou cetoconazol) após a armazenagem em água destilada ou S50 por 24 h, 7 e 14 dias. Os dados de resistência à tração (MPa) e percentagem de alongamento (%) foram submetidos à ANOVA de 3 fatores seguida pelo teste de Tukey (=0,05). Os dados de porosidade foram analisados estatisticamente por ANOVA de medidas repetidas para 4 fatores e teste de Tukey (=0,05). Ao final de 14 dias, a resistência à tração para ambos os materiais foi significativamente menor nos grupos modificados pelo miconazol e itraconazol em relação aos outros grupos (P<0,0001), que não mostraram diferenças significativas entre si (P>0,05). Após 7 e 14 dias em água, o miconazol e itraconazol adicionados a ambos os materiais resultaram em percentagens significativamente menores de alongamento em comparação com os outros fármacos e ao controle (P<0,0001), que foram semelhantes entre si (P>0,05). O cetoconazol não resultou em alterações significativas no FP para ambos os materiais resilientes em água ao longo de 14 dias (P>0,05). Em comparação aos controles, houve aumento dos FPs do Softone e Trusoft aos 14 dias de imersão em água somente após a adição de nistatina e clorexidina e de clorexidina, respectivamente (P<0,05). Ambos os materiais não apresentaram alterações significativas no FP em até 14 dias de imersão na S50, em comparação aos controles (P>0,05). Em todas as condições experimentais, os FPs do Softone e Trusoft foram significativamente menores quando imersos em S50 em comparação com a água destilada (P<0,05). Concluiu-se que a adição de nistatina, clorexidina e cetoconazol nas CIMs para o biofilme de C. albicans não resultou em efeitos deletérios na resistência à tração e na percentagem de alongamento dos materiais resilientes temporários para base de prótese até o período de 14 dias. A adição de antifúngicos nas CIMs não resultou em efeitos adversos à porosidade de ambos os materiais resilientes temporários em diferentes períodos de imersão em água, com exceção da clorexidina e nistatina no Softone e clorexidina no Trusoft aos 14 dias. Não foram observados efeitos deletérios para a porosidade de ambos os materiais resilientes modificados com as CIMs dos fármacos durante os 14 dias de imersão na S50.(AU)

This study investigated the tensile strength (ultimate tensile strength- UTS) and porosity of temporary soft denture liners modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm (SC5314). For UTS tests, dumbbell-shaped specimens (n=7) with a central cross-sectional area of 33 mm x 6 mm x 3 mm were produced by resilient materials (Trusoft and Softone) without (control) or with incorporation of five drugs at MICs: nystatin- 0.032 g; chlorhexidine diacetate-0.064 g; ketoconazole- 0.128 g; miconazole- 0.256 g; itraconazole- 0.256 g (each per gram of soft liner powder). After plasticization, specimens were immersed in distilled water at 37°C for 24 h, 7 and 14 days, and then tested in tension in a universal testing machine (EMIC DL-500 MF) at 40 mm/min. The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65 mm x 10 mm x 3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin, chlorhexidine or ketoconazole) after storage in distilled water or S50 for 24 h, 7 and 14 days. Data of tensile strength (MPa) and elongation percentage (%) were submitted to 3-way ANOVA followed by Tukey's test (=0.05). Data of porosity were statistically analyzed by 4-way repeated measures ANOVA and Tukeys test (=0.05). At the end of 14 days, the tensile strength for both materials was significantly lower in the groups modified by miconazole and itraconazole compared to the other groups (P<0.0001), which showed no significant difference between them (P>0.05). After 7 and 14 days in water, miconazole and itraconazole added into both materials result in significant lower elongation percentages compared to the other drugs and control (P<.0001), which were similar to each other (P>0.05). Ketoconazole resulted in no significant changes in PF for both liners in water over 14 days (P>0.05). Compared to the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of nystatin and chlorhexidine, and chlorhexidine, respectively (P<0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared to the controls (P>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared to distilled water (P<0.05). It was concluded that the addition of the nystatin, chlorhexidine and ketoconazole at MICs for C. albicans biofilm resulted in no harmful effects on the ultimate tensile strength and elongation percentage of the temporary soft denture liners up to 14-day period. The addition of antifungals at MICs resulted in no detrimental effects for the porosity of both temporary soft liners in different periods of water immersion, except for chlorhexidine and nystatin in Softone and chlorhexidine in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.(AU)

Comparison of the Minimum Fungicidal Concentration of Clotrimazole, Ketoconazole, Miconazole and Terbinafine Against Clinical Isolates of Dermatophytes.

Superficial fungal infections affect millions of people worldwide. Earlier most dermatophyte strains had relatively restricted geographical distribution. But currently, dermatophytosis has become one of the most common human infectious diseases worldwide. Fungal infections are common in hot and humid climate of tropical countries like India. Topical and systemic therapies are commonly used to treat dermatophyte infections.Clotrimazole is one of the most commonly used topical antifungal drugs. This study compared the minimum fungicidal concentration (MFC) of Clotrimazole with Miconazole, Ketoconazole and Terbinafine in skin dermatophytes. The study demonstrated that Clotrimazole had lower MFCs as compared to Ketoconazole and Miconazole against Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. Clotrimazole had comparable MFCs versus Terbinafine against Trichophyton rubrum but it had lower MFCs against Trichophyton mentagrophytes and Microsporum canis. Thus, Clotrimazole is an effective antifungal agent for dermatophytosis even today.The efficacy of Clotrimazole even against strains with intermediate resistance or resistance to the older azole anti fungal drugs reiterate the current decisions of empirical treatment with topical Clotrimazole for the management of superficial dermatophyte infections.

Antifúngicos de uso tópico no tratamento de micoses cutâneas ecaspa / Topical antifungals in the treatment of cutaneous mycosis and dandruff

As micoses superficiais estão entre os principais motivos de consultas dermatológicas e a caspa é uma queixa comum à grande parte dos indivíduos em algum momento da vida. Tais problemas são causados e/ou agravados por fungos. Com o objetivo de verificar qual a demanda e quais os principais antifúngicos utilizados em produtos dermatológicos, foram avaliadas, neste estudo, todas as formulações de uso externo produzidas em uma farmácia de manipulação na cidade de Londrina, Estado do Paraná, no primeiro semestre de 2006. Dentre os diferentes produtos, os antifúngicos foram os mais solicitados, compreendendo 17,19% da produção, sendo os ativos mais utilizados: cetoconazol, piritionato de zinco, violeta de genciana e miconazol. Foi observado aumento significativo na demanda, nos meses de fevereiro e março, em especial dos que contém cetoconazol e miconazol, sugerindo no verão, provavelmente, pelo calor e a maior frequência das pessoas nas piscinas e praias, a ocorrência de micoses é favorecida e por isso os cuidados higiênicos devem ser redobrados. O aumento na incidência de infecções fúngicas verificado nas últimas décadas deve servir de incentivo na busca de novos agentes antifúngicos eficazes, com menores efeitos adversos e de baixo custo, que auxiliem no tratamento de tais alterações cutâneas.

Superficial mycoses are among the main reasons for dermatological consultations, and dandruff is a common complaint of the majority of individuals at a given moment in life; such problems are caused and aggravated by fungi. With the objective of verifying what the demand is and which main antifungal drugs are used in dermatological products, all external use formulations produced at a prescription pharmacy in Londrina, Paraná State, during the first semester of 2006, were evaluated in this study. Among the different products, antifungals were the most requested, representing 17.19% of production.The most used active principles were: ketoconazole, zinc pyrithione, miconazole and gentian violet. During the months of February and March, a significant increase in demand was observed, especially on those products containing ketoconazole and miconazole. This suggests that in the summer, probably due to the heat and to the great frequency of people in swimming pools and beaches, the occurrence of mycoses is favored and, therefore, hygienic care should be redoubled. The increase in the incidence of fungal infections verified in the last decades should be a stimulus to search for new effective antifungal agent with fewer adverse effects and with low cost to help in the treatment of such cutaneous alterations.

Suction clearance and 2% topical miconazole versus the same combination with acidic drops in the treatment of otomycosis.

From April 2003 to September 2004, 59 ears from 55 patients received suction clearance and topical miconazole 2% (regimen 1) and in September 2004 to December 2005, 64 ears from 58 patients received the same combinations plus acidic drops [acetic acid 3% (v/ v) in 97% ethanol]. The mean age of patients treated with regimen 1 was 35.76+/-16 years and in regimen 2 was 37.98+/-15 years. Aspergilus sp and Candida sp were seen in 35 (59.3%) and 24 (40.7%) cases treated with regimen 1 and in 43 (67.2%) and 21 (32.8%) cases treated in regimen 2, respectively. Relapse occurred in 2 (3.4%) ears treated with regimen 1, but none in cases treated with regimen 2 (p=0.228). The findings reveal that there were no statistically significant differences between the two regimens and both may be used for the treatment of otomycosis.

The use of the antifungal agent miconazole as an inhibitor of Blastocystis hominis growth in Entamoeba histolytica/E. dispar cultures

In regions with high prevalence, Blastocystis hominis is frequently found in association with Entamoeba histolytica/E. dispar in xenic cultures. Its exacerbated growth is often superimposed on the growth of amebas, thus impeding the continuation of the amebas in the culture, within a few generations. The present study reports on the excellent efficacy (100 percent) of the antifungal agent miconazole in eliminating B. hominis from cultures of E. histolytica/E. dispar, thereby maintaining the integrity of the trophozoites of the amebas. Nystatin presented low efficacy (33.3 percent).

Em regiões de alta prevalência, Blastocystis hominis é freqüentemente encontrado em associação com Entamoeba histolytica/E. dispar em cultivos xênicos. Seu crescimento exacerbado se sobrepõe muitas vezes ao das amebas, impedindo a manutenção destas em cultura, dentro de poucas gerações. O presente estudo relata a excelente eficácia (100 por cento) do antifúngico miconazol na eliminação de B. hominis dos cultivos de E. histolytica/E. dispar, mantendo-se a integridade dos trofozoítos das amebas. A nistatina apresentou eficácia baixa (33,3 por cento).

Minimum inhibitory concentration of adherence of Punica granatum Linn (pomegranate) gel against S. mutans, S. mitis and C. albicans

The purpose of this study was to investigate the antimicrobial effect of a Punica granatum Linn (pomegranate) phytotherapeutic gel and miconazole (Daktarin® oral gel) against three standard streptococci strains (mutans ATCC 25175, sanguis ATCC 10577 and mitis ATCC 9811), S. mutans clinically isolated and Candida albicans either alone or in association. The effect of minimum inhibitory concentrations of the gels on the adherence of these microorganisms to glass was assessed in the presence of 5 percent sucrose, using increasing and doubled concentrations of the diluted solution of the gels ranging from 1:1 to 1:1024. The minimum inhibitory concentrations of adherence of Punica granatum L. gel against the test organisms were: 1:16 for S. mutans (ATCC), S. mutans (CI) and S. sanguis; 1:128 for S. mitis and 1:64 for C. albicans. The minimum inhibitory concentrations of adherence of miconazole against the same organisms were: 1:512, 1:64, 1:4, 1:128 and 1:16, respectively. In experiments with three and four associated microorganisms, the Punica granatum L. gel had greater efficiency in inhibiting microbial adherence than the miconazole. The results of this study suggest that this phytotherapeutic agent might be used in the control of adherence of different microorganisms in the oral cavity.

O propósito deste estudo foi investigar a concentração inibitória mínima de aderência (CIMA) de três linhagens de estreptococos (mutans ATCC 25175, sanguis ATCC 10557 e mitis ATCC 9811), S. mutans isolado clinicamente e de cepas de Candida albicans, separadamente ou associadas, frente a um gel fitoterápico obtido da Punica granatum Linn. (romã) e ao agente antifúngico miconazol (Daktarin® gel oral). A concentração inibitória mínima de aderência das bactérias ao vidro foi determinada na presença de sacarose a 5 por cento, usando-se concentrações crescentes e dobradas da solução diluída do gel variando de 1:1 a 1:1024. Os valores de inibição do gel fitoterápico foram de 1:16 para S mutans (ATCC), S. mutans (IC) e S. sanguis; 1:128 para S. mitis e 1:64 para C. albicans. Sobre as mesmas linhagens, as concentrações inibitórias mínimas de aderência do miconazol foram: 1:512, 1:64, 1:4, 1:128, 1:16 respectivamente. O gel da romã apresentou maior eficácia sobre associações de três e quatro microrganismos do que o gel do miconazol. Os achados deste estudo sugerem o emprego desse agente fitoterápico pode ser uma opção no controle da aderência dos microrganismos testados na cavidade bucal.

In vitro antifungal susceptibility of Candida spp. isolates from patients with chronic periodontitis and from control patients

Em certas situações, tal como em pacientes imunocomprometidos, superinfecção por Candida pode ocorrer e ser refratária ao tratamento periodontal convencional. Nesses casos, a terapia sistêmica com antifúngicos pode ser indicada. O objetivo deste trabalho foi estudar a suscetibilidade aos antifúngicos de cepas de leveduras do gênero Candida isoladas de pacientes com periodontite crônica e de indivíduos controle. Um total de 39 isolados de C. albicans, 9 de C. tropicalis, 2 de C. glabrata e 5 de Candida spp. provenientes de indivíduos controle e 30 de C. albicans, 3 de C. tropicalis e 2 de C. glabrata de pacientes com periodontite foram testados. No grupo controle, uma amostra de C. glabrata foi resistente ao cetoconazol e uma de Candida spp. mostrou-se resistente a anfotericina B, cetoconazol e miconazol. Dentre as amostras do grupo com periodontite, uma (3,33%) amostra de C. albicans foi resistente à 5-fluorocitosina e ao cetoconazol. A partir dos resultados obtidos, concluiu-se que fluconazol foi o fármaco mais eficaz contra as várias espécies de Candida estudadas. Não foram observadas diferenças expressivas na sensibilidade de isolados de pacientes com periodontite e de indivíduos controle.

A study of dermatophytes and their in-vitro antifungal sensitivity.

Of the 150 clinically suspected cases of Dermatophytosis studied, majority of the cases were from age group 11-20 and 21-30 (51.4%), Tinea corporis (48.7%) and Tinea capitis (18%) were the commonest clinical types. The isolation rate was 24% (36) of which 19 (52.7%) were Trichophyton rubrum, 11 (30.55%) were Trichophyton mentagrophytes and 4 (11.1%) were Trichophyton violaceum. One isolate each of Microsporum gypseum & Epidermophyton floccosum were obtained. Griseofulvin proved to be the best drug with a sensitivity of 94.4% followed by Miconazole (75% sensitive). Tolnaftate showed a sensitivity of 47.22%. For Clotrimazole only 30.55% of the isolates were sensitive.

Mechanism of cAMP-induced H(+)-efflux of Dictyostelium cells: a role for fatty acids.

Aggregating Dictyostelium cells release protons when stimulated with cAMP. To find out whether the protons are generated by acidic vesicles or in the cytosol, we permeabilized the cells and found that this did not alter the cAMP-response. Proton efflux in intact cells was inhibited by preincubation with the V-type H(+) ATPase inhibitor concanamycin A and with the plasma membrane H(+) ATPase blocker miconazole. Surprisingly, miconazole also inhibited efflux in permeabilized cells, indicating that this type of H(+) ATPase is present on intracellular vesicles as well. Vesicular acidification was inhibited by miconazole and by concanamycin A, suggesting that the acidic vesicles contain both V-type and P-type H(+) ATPases. Moreover, concanamycin A and miconazole acted in concert, both in intact cells and in vesicles. The mechanism of cAMP-induced Ca2(+)-fluxes involves phospholipase A2 activity. Fatty acids circumvent the plasma membrane and stimulate vesicular Ca2(+)-efflux. Here we show that arachidonic acid elicited H(+)-efflux not only from intact cells but also from acidic vesicles. The target of regulation by arachidonic acid seemed to be the vesicular Ca2(+)-release channel.

Interações entre vesículas catiônicas e superfícies biológicas: lipossomos de brometo de dioctadecildimetilamônio (DODAB) como agentes antimicrobianos / Interactions between cationic vesicles and biological surfaces: dioctadecyldimethylammonium bromide (DODAB) vesicles such as antimicrobial agents

Lipossomos são vesículas microscópicas compostas de uma ou mais membranas lipídicas envolvendo um compartimento aquoso, e podem ser constituídos de moléculas naturais ou sintéticas, como o brometo de dioctadecildimetilamônio (DODAB), um composto de amônio quaternário. Este trabalho mostra: 1) susceptibilidade de quatro espécies bacterianas à ação bactericida de DODAB; 2) verificação da ação antifúngica de DODAB; 3) solubilização de duas drogas antifúngicas (anfotericina B e miconazol) nos lipossomos de DODAB; 4) verificação da eficiência das drogas incorporadas aos lipossomos, como agentes antifúngicos. A susceptibilidade das espécies ao DODAB foi avaliada através de curvas de viabilidade celular para 2,5 x `10 POT. 7' UFC/mL. A bactéria mais resistente foi Escherichia coli, seguida de S. Typhimurium, P. aeruginosa, e S. aureus...

Changes in the cellular composition of Candida albicans resistant to miconazole.

Biochemical changes that accompany acquisition of miconazole resistance in a single step mutant of C. albicans 3153 were analyzed. Experiments show that resistance to this drug was associated with decrease in total lipids, phospholipids and sterol content. Fluorescence polarization studies with 1,6-diphenyl-1,3,5-hexatriene (DPH) showed decrease in polarization value (p) in resistant cells, thus indicating changes in membrane fluidity. Uptake of [3H] proline by intact cells revealed decrease in K(m) and Vmax of high affinity system (S1) of proline transport in cells resistant to miconazole. Results of this study suggest that membrane sensitivity of miconazole is determined by overall membrane organisation rather than by affinity of antifungal drug(s) for a single membrane component.

Disk diffusion susceptibility testing of dermatophytes with imidazoles.

In vitro susceptibility testing of 43 isolates of dermatophytes was carried out against imidazoles-ketoconazole, miconazole and econazole and griseofulvin by agar dilution and disk diffusion methods. Econazole was the most effective drug inhibiting all the isolates at a concentration of 0.1 microgram ml-1. The MIC 50s and MIC 90s for ketoconazole and miconazole were 1 and 2.5 mg ml-1 whereas the values for griseofulvin were 1 and 5 micrograms ml-1. Good correlation was seen between the MIC and sizes of zones of inhibition around the disks. Regression analysis was used to measure the degree of correlation between the MIC values and matched averaged zones of inhibition and the correlation coefficients for econazole, ketoconazole, miconazole and griseofulvin were -0.5554, -0.5886, -0.8558 and -0.8268 (p < 0.001) respectively.

In vitro evaluation of three topical antimycotics against ring-worm fungi singly and in combination.

Three antimycotic drugs, viz., Miconazole nitrate, Econazole nitrate and ciclopirox olamine were tested singly and in combination of miconazole nitrate and Econazole nitrate, Miconazole nitrate and Ciclopirox olamine, and Econazole nitrate and Ciclopirox olamine to evaluate in vitro efficacy against Trichophyton mentagrophytes and Macrosporum nanum. The best efficacy was shown by Ciclopirox olamine (MIC 0.78 microgram/ml) and a combination of Miconazole nitrate and Econazole nitrate (MIC 0.78 microgram/ml).

Effect of supplementation of ergosterol on miconazole action in vivo and in vitro in Candida albicans.

Ergosterol was observed to alter the lipid composition of C. albicans 3153 selectively, resulting in steep rise in ergosterol content with marginal changes in other lipids content. Supplementation of ergosterol in presence or absence of cerulenin made cells more protective towards the miconazole drug. However, when the same experiments were carried out with liposomes prepared from the lipid extracts of control and supplemented cells, the pattern obtained show a little deviation from the in vivo experiments thus indicating that in addition to lipids, other cell components like proteins also affect interaction of miconazole with C. albicans.

Structure to antimycotic activity of benzylid enechromanones against 6 miconazole-resistant pathogenic yeasts in vitro

Fifty-five new compounds belonging to the naturally occurring benzylidene chromanones were synthesised and their activity against the important human pathogenic yeasts Cryptococcus neoformans, Candida spp., Trichosporon cutaneum and Torulopsisgh brata was assessed in vitro using a microtitre technique. These yeasts had already been found resistant to miconazole, at a minimum inhibitory concentration [MIC] of 100 micro g/ml or more The structural differences between the molecules of the new compounds, such as their three dimensional shape, the presence of oxygen or sulphur hetero-atoms, or a cyclic bridge, were studied to establish models for their structure-to-antimycotic activity. Twenty-eight of the compounds were found active against the tested yeasts and had an MIC of 6 micro g/ml. There was a heterogeneity in the response of the yeasts to the active compounds, which could be linked to structural factors in C. neoformans

Susceptibilidad "in vitro" de cepas de Cryptococcus a 5 drogas antifúngicas / In vitro susceptibility of Cryptococcus strains to 5 antifungal drugs

Se estudió la susceptibilidad "in vitro" de 24 cepas de 3 espécies del género Cryptococcus a 5 drogas antifúngicas (antrotericina B, 5 fluorocitosina, ketoconazol, itraconazol y miconazol). Las mismas se agruparon según su especie, variedad y origen de aislamiento. Para determinar la concentración inhibitoria mínima (C.I.M.) de cada droga se empleó el método de dilución en agar con el medio básico nitrogenado para levaduras, adicionado de glucosa. Se obtuvo además la media geométrica de estos valores para cada grupo y se comparó cada uno de ellos. Los resultados obtenido fueron homogéneos con la sola excepción de las cepas de Cryptococcus sp (no neoformans), en las cuales se detectaron elevados valores de C.I.M. para la 5 fluorocitosina

Evaluación de la actividad tripanicida in vitro de tres agentes antimicóticos sobre plasmas frescos infectados con T. Cruzi / Evaluation of the tripanicidad activity in vitro of 3 antimycotical agentes on fresh plasma infected with T. Cruzi

Siendo la incidencia de Chagas aún elevada en nuestros donantes de sangre y debido a que con frecuencia existe escasez de plasma y crioprecipitado para el tratamiento de los pacientes hemofílicos, se diseñó el siguiente trabajo con el fin de determinar si era posible usar estos hemoderivados infectados y debidamente pre-tratados profilácticamente, sin ningún riesgo para el receptor. Para este estudio se tomó plasma fresco Chagas negativo, el cual se inoculó con concentraciones conocidaas de Tripanosoma cruzi (Tc) y se incubó con los siguientes antimicóticos: Anfotericina B, Candicidina y Miconazol. El efecto de las drogas sobre el parásito se evaluó en placas de microtítulo de fondo plano, en las cuales se incubaron: 1.10 6 Tc/pozo con diluciones seriadas de los antimicóticos (Anfotericina B de 10 a 0,07 *g/ml, Candicidina de 0,6 a 0,01 *g/ml y Miconazol de 5.10-5 a 1.10-6 *g/ml). Se determinó la concentración que producía la muerte de los parásitos, puesta en evidencia por la pérdida de su movilidad, observada en el microscopio invertido cada 30 minutos, durante 3 horas. Para definir más precisamente la viabilidad de los parásitos se incubaron 2.10 5 y 2.10 6 Tc/ml de plasma con Anfotericina B a razón de 1 *g/ml, Candicidina a 1,2 *g/ml y Miconazol a 1.10 4 *g/ml por 3 horas a 4-C y luego se incubaron en cámaras de microcultivo de células por quintuplicado. Después de 14 días a 37-C se procesaron las cámaras y se determinó por observación microscópica la presencia de células infectadas. En base a este estudio se concluyó que la Anfotericina B tiene mayor capacidad tripanicida sobre el plasma...

Susceptibilidad "in vitro" de cepas de dermatófitos frente a drogas utilizadas en micoticoterapia: método cuantitativo para hongos filamentosos / In vitro susceptibility of dermatophyte strains to drugs used in mycosis therapy: quantitative method for filamentos fungi

Teniendo en cuenta las diversas técnicas que se emplean para determinar el poder antimicótico de algunas drogas sobre hongos filamentosos, se realizó un modelo experimental que permitió evaluar cuantitativamente la acción fungicida de distintos quimioterápicos en diferentes cepas de dermatofitos (aislados de dermatomicosis). Para determinar cuantitativamente el desarrollo de un hongo filamentoso se lo disgregó en solución fisiológica estéril con cidrio molido o utilizando un homogeneizador de tejidos. En el caso de dermatofitos los inóculos fueron llevados a concentración final de 400 macroconidias/ml para las distintas cepas de Microsporum, 44 macroconidias/ml en las cepas de Epidermophyton y 125 microconidias/ml en las cepas de Trichophyton, utilizando para tal fin una cámara de Neubauer. Con los inóculos obtenidos de esta manera se realizaron las diluciones apropiadas para contar en placas con Sabourad-dextrosa 160-180 unidades formadoras de colonias (UFC) para las cepas pertenecientes al género Microsporum, 100-150 UFC para las pertenecientes al género Epidermophyton y 160 UFC en las cepas de Trichophyton, al cabo de 7 días de incubación a 28-C. Al utilizar este modelo experimental con concentraciones crecientes de diferentes antifúngicos se puede determinar cuantitativamente la acción de éstos "in vitro", de acuerdo a la disminución del número de UFC de las cepas de dermatofitos estudiadas. Para evaluar esta metodología de cuantificación se utilizaron los dermatofitos. Puede ser aplicable a otros hongos filamentosos inclusive a los productores de micoses sistémicas