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F Mínguez

Publications and source records attributed to F Mínguez.

10 recordsLinked to original sources
PubMed2002

Postantifungal effect and effects of sub-MIC concentrations on previously treated Candida sp. influence of growth phase.

OBJECTIVES: This study evaluates the influence of growth phase on the postantifungal effect (PAFE) and on the effect of sub-MIC concentrations (1/4x MIC) on Candida sp. in PAFE stage (PAFSE). METHODS: This stage was induced by pre-treatments of 1.5 h of C. albicans or C. glabrata in their exponential or stationary phase, with 1x, 4x or 8x MIC of four antifungal agents that are fundamental for modern candidiasis therapy. RESULTS: Ketoconazole and fluconazole induced longer PAFSEs on microorganisms in logarithmic growth phase. However, this influence did not exist in the case of PAFSEs induced by AmB and 5-Fc or with the postantifungal effect induced by the four antifungal agents. In any way, significant PAFEs were always observed for Amphotericin B and 5-fluorocytosine (0.8-4.8 and 0.5-3 h, respectively, depending on the treatment dose). These values were increased (2.3-3.6 and 1.4-3.2 h respectively, depending on the pre-treatment dose) by posterior exposition to 1/4x MIC of the respective antifungal agent. In the case of ketoconazole and fluconazole, both antimycotics were not able to induce significant PAFEs, but posterior treatments to 1/4x MIC of each of the two azoles led in both yeast species to significant PAFSE of up to 2.6 h duration with ketoconazole, and 0.8 h with fluconazole, depending on the pre-treatment concentration. CONCLUSION: The growth phase of microorganisms should be considered in the planning of dosage protocols with azoles, because if the concentration applied is not high enough, the sub-MIC effects could be no significant for fungi in stationary phase of large wounds. Amphotericin B and 5-fluorocytosine induced significant postantifungal effect onCandida sp. This effect was increased by posterior exposition to sub-MIC concentration of the antifungal agents. Ketoconazole and fuconazole were not able to induce significant PAFEs at the concentrations tested, but posterior treatments to sub-MIC concentrations led to significant PAFSE. The growth phase of the culture at the time of its pre-treatment did not influence the length of the PAFE induced in it. However, the effect of the sub-MIC concentrations of Kz or Flu in yeast in PAFE phase was greater on yeast in exponential phase than for cultures in stationary phase.

Antifungal Agents↗
PubMed2002

Post-antifungal effect and effects of sub-MIC concentrations on previously treated Candida spp.: influence of exposure time and concentration.

This study evaluates the influence of exposure time and concentration on the post-antifungal effect (PAFE) and the effect of sub-MIC concentrations (1/4 x MIC) on Candida albicans and C. glabrata in the PAFE stage (PAFSE). This stage was induced by pretreatment for 1.5, 3 or 12 h with 1 x, 4 x or 8 x MIC of 4 antifungal agents fundamental to modern candidiasis therapy. The length of the 2 effects studied was dependent on the concentration of the antifungal agent applied during pretreatment, as well as on the exposure time. An increase in the dose and/or longer pretreatment prolonged the duration of the PAFE and PAFSE in both species and with all the antifungal agents. Significant PAFEs were always observed for amphotericin B and 5-fluorocytosine (0.8-13 h and 0.6-10.8 h, respectively). These values were increased (by 2.3-8.7 h and 1.5-7.8 h, respectively) by posterior exposure to 1/4 x MIC of the respective antifungal agent. Neither ketoconazole nor fluconazole were able to induce significant PAFEs, even with exposures of up to 12 h duration and a dose of 8 x MIC. However, treatment with 1/4 x MIC of each of the 2 azoles led to significant PAFSEs in both yeast species, of up to 6.5 h duration with ketoconazole and 1.7 h with fluconazole, if the concentrations and/or exposure times were sufficiently high.

Amphotericin B↗
PubMed2000

Influence of pH and concentration on the postantifungal effect and on the effects of sub-MIC concentrations of 4 antifungal agents on previously treated Candida spp.

This study investigates the impact of different pH values (5.5 and 7.4) on the postantifungal effect (PAFE) and the effect of sub-MIC concentrations (1/4 x MIC) on C. albicans and C. glabrata in the PAFE stage (PAFSE). The PAFE stage was induced by a 1.5 h pretreatment with different doses (1, 4 and 8 x MIC) of 4 antifungal agents. An increase in the pH and/or an increase in the dose of the antimycotic prolonged the duration of the PAFE induced by amphotericin B or 5-fluorocytosine and the PAFSE induced by all 4 antifungal agents in both species. 5-Fluorocytosine and amphotericin B (except for treatment with 1 x MIC at pH 5.5) induced significant PAFEs (0.5-3.0 h and 1.4-4.8 h, respectively), which were increased (to 0.9-3.2 h and 0.8-3.4 h, respectively) by posterior (PLEASE EXPLAIN WHAT YOU MEAN BY THE WORD "POSTERIOR" HERE) exposure to 1/4 X MIC of the respective antifungal agent. Although ketoconazole and fluconazole were not able to induce significant PAFEs, posterior exposure to 1/4 x MIC of each of these 2 azoles led to significant PAFSEs of up to 2.6 h in both yeast species when the concentrations and pH were high enough.

Amphotericin B↗
PubMed1999

Activity of voriconazole: post-antifungal effect, effects of low concentrations and of pretreatment on the susceptibility of Candida albicans to leucocytes.

This study examined: (i) the post-antifungal effect (PAFE) of Voriconazole (UK 109,496) on Candida albicans, at 2 concentrations (MIC and 4 x MIC) in the presence or absence of 10% human serum; (ii) the activity of low concentrations of the drug (1/4 x MIC) on yeasts that had previously been exposed to Voriconazole (PAFSE) with or without 10% human serum; and (iii) the effect of Voriconazole pretreatment on the fungicidal activity of leucocytes and serum against C. albicans (PALE). Two concentrations (0.25 and 1 mg/l) of Voriconazole induced no PAFE against C. albicans between -4.3 and -1.4 h, but when the assays were performed in the presence of serum, positive and concentration-dependent PAFEs were obtained (0.2-4.1 h). Pretreated yeasts were more susceptible than untreated yeasts to low concentrations (0.0625 mg/l) of Voriconazole, so the drug showed positive PAFSE that was dependent on the concentration used in pretreatment without serum (0.3-1.9 h) or with 10% human serum (0.5-2.5 h). Pretreatment of the growing C. albicans cells with Voriconazole (0.25 mg/l) increased their vulnerability to killing by leucocytes during the last 2 h (p < 0.05), leading to PALE of 2 h. The results suggest that these effects might be used to evaluate the in vivo activity of an antifungal agent. The sum of the durations of these effects (PAFE, PAFSES and PALE) cause a considerable delay in yeast growth in treated cultures compared with control cultures.

Antifungal Agents↗
PubMed1998

[Descriptive study of complications caused by mediastinoscopy].

To analyze the surgical and non surgical complications of mediastinoscopy in a series of 200 consecutive patients. Retrospective study of all surgical patients between 1 January 1994 and 1 May 1997. Any complication presenting between time of surgery and patient release is analyzed. Complications were seen in 8 out of 200 cases (4%). In three cases, there were lesions in neighboring structures (recurrent nerve, bronchial artery and innominate artery). The rest were non surgical complications (3 cases of arrhythmia, 2 of prolonged mechanical ventilation). One male patient (0.5%) died from cerebral infarction, probably as a result of arterial occlusion needed to suture damage to the innominate artery. Superior win cava syndrome affected 20% (1 in 5) and morbidity was 60% (3 in 5). Morbidity involving both medical and surgical complications in this series is higher than that reported elsewhere in the literature, in series for which non surgical complications go unreported.

Aged↗
PubMed1996

Postantifungal effect and effects of low concentrations of amphotericin B and fluconazole on previously treated Candida albicans.

The objective of the study was to assess (a) the postantifungal effect (PAFE) of amphotericin B (AmB) and fluconazole (Flu) on two Candida albicans strains, and (b) the effect of low concentrations of AmB or Flu on yeasts previously exposed to AmB or Flu, respectively, in the presence or absence of 10% human serum. In the absence of serum, AmB exerted a positive effect (at 0.5-5.0 h) depending on the concentration and the strain used. Flu, however, produced negative effects (at -1.2 to -0.1 h). When the experiment was conducted in the presence of serum, the duration of all PAFEs increased significantly, especially those induced by Flu that became positive. Pretreated yeasts were more susceptible than untreated controls to the antifungal activity of low concentrations of the drugs. Growth delay was more pronounced with Flu (up to 5.2 h), whereas the greatest decrease in log10 at 12 h was slightly more pronounced for AmB. A knowledge of PAFEs and the effects of low drug concentrations on pretreated yeasts and the effects of serum on these is important in order to gain more insight into the in vivo activity of the study drugs.

Amphotericin B↗
PubMed1990

[Influence of bacterial combinations on the post-antibiotic effect].

A study of the post-antibiotic effect (PAE) and letality curves of different concentrations of clavulanic acid, amoxycillin, amoxycillin + clavulanic acid, netilmycin and ofloxacin on mixed cultures of S. aureus and E. coli. The post-antibiotic effect was measured after one hour of exposure of bacteria to antimicrobial and the elimination of the latter by the dilution method. Amoxycillin did not induce PAE on the association. PAE only appeared at high concentrations on S. aureus when evaluated alone. Clavulanic acid induced a greater PAE than amoxycillin. The association clavulanic acid + amoxycillin was synergistic and induced a greater PAE than its components. Netilmycin and ofloxacin were the drugs that induced the greatest PAE on the bacterial association and on its strains independently evaluated.

Amoxicillin↗
PubMedDate not supplied

Influence of temperature and concentration on the postantifungal effect and the effects of sub-MIC concentrations of four antifungal agents on previously treated Candida species.

BACKGROUND: The objective of this study was to investigate the impact of different temperatures (22, 35 and 37 degrees C) on the postantifungal effect (PAFE) and the effect of sub-MIC concentrations (1/4 x MIC) on Candida albicans and Candida glabrata in PAFE stage (PAFSE). METHODS: This stage was induced by a 1.5-hour pretreatment with different doses (1 x, 4 x and 8 x MIC) of four antifungal agents that are fundamental to modern candidiasis therapy. RESULTS: The temperature, as well as the dose of the antifungal agent that was applied during the pretreatment, determined the duration of the two studied effects. An increase in the temperature and/or the dose prolonged the duration of the PAFE and PAFSE in both species, independent of the applied antifungal agent. Amphotericin B and 5-fluorocytosine always induced significant PAFEs (0.5-4.8 h and 0.5-3.0 h, respectively), which were increased (0.7-3.4 h and 0.5-3. 2 h, respectively) by posterior exposure to 1/4 x MIC of the respective antifungal agent. In the case of ketoconazole and fluconazole, temperature and concentration were especially important. Although neither antimycotics was able to induce a significant PAFE, posterior exposure to 1/4 x MIC of each of the two azoles led in both yeast species to a significant PAFSE of up to 0.8 h (if the concentrations and/or the temperatures were high enough). CONCLUSION: Factors such as temperature and concentration could be important when choosing an antifungal agent.

Antifungal Agents↗
PubMedDate not supplied

Influence of human serum on the postantifungal effect of four antifungal agents on Candida albicans.

This study evaluates the influence of both fresh and heated human serum on the postantifungal effect (PAFE) induced by different concentrations of amphotericin B (AmB), 5-fluorocytosine (5-Fc), Ketoconazole (Kz) and fluconazole (Flu) on two strains of Candida albicans. The concentrations were selected in harmony with the pharmacokinetic properties and toxicity of the drugs. Without serum there was no delay in the growth of yeast cultures pretreated with Kz or Flu, leading to negative PAFEs, however with AmB and 5-Fc the PAFEs were positive. When assays were made in the presence of 10% fresh human serum, the duration of the PAFEs increased with all drugs tested, and those induced by azolic agents became positive. In the presence of 10% human serum heated at 56 degrees C for 30 min, the PAFEs of the antifungal agents were similar to those obtained in the absence of serum. Our results suggest that fresh serum positively influenced PAFE which may be an important factor in determining the dosing regimen for infection by yeasts.

Amphotericin B↗