Efficacy of a single 6 mg/kg versus two 3 mg/kg caspofungin doses for treatment of disseminated candidiasis caused by Candida albicans in a neutropenic mouse model.

We compared the efficacy of single six mg/kg and 2x3 mg/kg caspofungin doses to the traditional one mg/kg daily against C. albicans in a neutropenic murine model. In lethality experiments, all regimens improved survival (p<0.0014 for all three isolates); differences among the treated groups were not statistically significant. We calculated kidney fungal burdens on each study day for six days postinfection using two isolates in two experiments. In the first three days, only the six mg/kg dose produced significant decrease on all study days (p<0.05-0.001), but differences between the three treatment arms disappeared by 4-6 days postinfection (p<0.05 for all isolates on all days).

In vitro efficacy of amphotericin B, 5-fluorocytosine, fluconazole, voriconazole and posaconazole against Candida dubliniensis isolates using time-kill methodology.

Candida dubliniensis is a recently described yeast that causes infections in mucosal surfaces as well as sterile body sites. Candida dubliniensis develops resistance to fluconazole (FLC) more rapidly than the closely related species C. albicans. The killing activity of amphotericin B (AMB), 5-fluorocytosine (5FC), FLC, voriconazole (VRC) and posaconazole (POS) was determined against six C. dubliniensis clinical isolates, identified using molecular biological methods and C. dubliniensis CD36 reference strain. Minimum inhibitory concentrations (MICs) were determined using the Clinical and Laboratory Standards Institute standard procedure. Time-kill assays were performed using RPMI-1640 as test media over a 48-h period. AMB proved to be fungicidal at >or=0.5 microg ml(-1) against all clinical isolates after 48 h. 5FC was only fungicidal at 32-64x MIC (4-8 microg ml(-1)) against all C. dubliniensis isolates. FLC, VRC and POS were fungistatic; decrease in colony number was observed only at the highest concentrations tested (8, 4 and 4 microg ml(-1), respectively). Triazoles invariably showed fungistatic effect at concentrations attainable in the serum. In clinical situations when a fungicidal antifungal is desirable, AMB may be used.

Difference in killing activity of caspofungin and paradoxical growth between Candida albicans and C. krusei clinical isolates in different media.

Minimum fungicidal concentration (mFC) of caspofungin was determined against 16 Candida albicans and 16 C. krusei in Rpmi-1640 and antibiotic medium 3 (Am3). time-kill tests were performed on six C. albicans and four C. krusei strains at 0.06-16 mg/l caspofungin. mFC ranges after 48 h were 0.5-1 and 1-2 mg/l for C. albicans and C. krusei, respectively; one C. albicans and the C. krusei reference strain showed paradoxical growth (pG) in Rpmi-1640, respectively. in killing experiments, after 48 h caspofugin was fungicidal against two and four C. albicans in Rpmi-1640 (at 16 mg/l) and in Am3 (at >0.5 mg/l), respectively; pG was noted in three and two cases, respectively. Caspofungin at >2 and 0.5 mg/l was fungicidal against all tested C. krusei strains even after 24 h in Rpmi-1640 and Am3, respectively. Killing activity of caspofungin against C. albicans and C. krusei could be exactly measured only by killing curves.

Antiproliferative effect of 4-thiouridylate on OCM-1 uveal melanoma cells.

PURPOSE: Brachytherapy is a well-established, effective treatment for uveal melanoma with a failure rate of 15%. The fatal consequence of unsuccessful treatments offers reason for improvement of the method. The authors propose using an apoptosis inducing agent locally, concomitantly with the well-established therapy, to sensitize the tumor cells. The authors propose a new nontoxic moderately active apoptosis inducing agent, 4-thio-uridylate (s4UMP), for this purpose. METHODS: OCM-1 uveal melanoma cells were treated with various concentrations of s4UMP and its effect was monitored by measuring the cell viability (MTT assay). The following apoptosis detecting methods were performed to reveal the mechanism of decreased cell viability: light microscopy, DNA fragmentation assay, determination of caspase 9 activity, and FACS analysis. RESULTS: The viability of uveal melanoma cells was decreased by 32%, 40%, and 9% after 24, 48, and 72 hours of treatment with 10 microg/mL (30 microM) s4UMP. The effect was not dose dependent; it rather followed a saturation-type inhibition and the cells at lower drug concentration recovered after 72 hours. Characteristic apoptotic cell morphology and DNA fragmentation was detected in treated cells. The caspase-9 was activated upon treatment showing maximal activity at 48 hours suggesting the induction of apoptosis. The annexin binding activity further verified the apoptogenic activity of s4UMP. CONCLUSIONS: Uveal melanoma, more than other solid tumors, is resistant to most of the chemotherapeutic protocols as indicated by the high mortality rate of metastatic disease. The authors showed that s4UMP, a naturally occurring nucleotide, could induce apoptosis in uveal melanoma cells, suggesting a potential supplementary therapeutic application of the compound.

Antiproliferative effect of 4-thiouridylate on OCM-1 uveal melanoma cells.

PURPOSE: Brachytherapy is a well-established, effective treatment for uveal melanoma with a failure rate of 15%. The fatal consequence of unsuccessful treatments offers reason for improvement of the method. The authors propose using an apoptosis inducing agent locally, concomitantly with the well-established therapy, to sensitize the tumor cells. The authors propose a new nontoxic moderately active apoptosis inducing agent, 4-thio-uridylate (s4UMP), for this purpose. METHODS: OCM-1 uveal melanoma cells were treated with various concentrations of s4UMP and its effect was monitored by measuring the cell viability (MTT assay). The following apoptosis detecting methods were performed to reveal the mechanism of decreased cell viability: light microscopy, DNA fragmentation assay, determination of caspase 9 activity, and FACS analysis. RESULTS: The viability of uveal melanoma cells was decreased by 32%, 40%, and 9% after 24, 48, and 72 hours of treatment with 10 g/mL (30 M) s4UMP. The effect was not dose dependent; it rather followed a saturation-type inhibition and the cells at lower drug concentration recovered after 72 hours. Characteristic apoptotic cell morphology and DNA fragmentation was detected in treated cells. The caspase-9 was activated upon treatment showing maximal activity at 48 hours suggesting the induction of apoptosis. The annexin binding activity further verified the apoptogenic activity of s4UMP. CONCLUSIONS: Uveal melanoma, more than other solid tumors, is resistant to most of the chemotherapeutic protocols as indicated by the high mortality rate of metastatic disease. The authors showed that s4UMP, a naturally occurring nucleotide, could induce apoptosis in uveal melanoma cells, suggesting a potential supplementary therapeutic application of the compound.