Hyperthermia increases the metastatic potential of murine melanoma

Hyperthermia, either alone or combined with radio-, immuno- or chemotherapy, can control tumor growth, but its effect on metastasis is still controversial. In the present study, we investigated the influence of hyperthermia on the metastatic potential of B16-F10 murine melanoma cells. Incubation of melanoma cells at 43ºC for 30 min led to a significant decrease in cell viability. About half of the cells survived the acute exposure to heat. These thermoresistant cells displayed a longer lag phase as compared to control unheated B16-F10 melanoma cells. Other parameters of cell growth such as doubling time and saturation density were equivalent in both control and thermoresistant cells. Both control and treated cells were adherent, but thermoresistant cells failed to spread during the first 48 h after heat exposure. B16-F10 cells colonize the lungs of C57BL/6J mice when injected intravenously; the number of lung colonies is a measure of the metastatic potential of injected cells. Median values of 22, 10.5 and 31 colonies per injected mouse were observed for control cells, cells heated to 43ºC for 30 min and thermoresistant cells, respectively, with statistically significant differences between groups (Mann-Whitney test, P<0.02). Thus, despite its cytotoxic action, heat exposure induced the acquisition of a more metastatic phenotype in a subpopulation of B16-F10 cell

In vitro susceptibility of coliform and Pseudomonasspecie to some antibiotics by E-test strips

The aim of this study was to characterize the in vitro antimicrobial susceptibility profile of Coliform and Pseudomonas species strains to 10 antibiotics (Vancomycine, Ciprofloxine, Tetracyclin, Chloramphenicol , Erythromycin, Streptomycine, Gentamycine , Ampicilline, trimethoprimsulfamethoxazole and Clarithromycin) that could potentially be used in clinical therapy. MIC was determined for antibiotics in Mueller-Hinton (MH) agar plates, by using E-test strips (Liofilchem, Roseto degli Abruzzi, Italy). MIC was read after 24 h of incubation at 37°C. The both strains were more susceptible to Ciprofloxine (MIC values: Coliform, 0.002 μg/mL; and Pseudomonas, 0.047 μg/mL). No strain of Pseudomonas was found sensitive to Chloramphenicol, Erythromycin, Ampicilline, trimethoprim-sulfamethoxazole and Clarithromycin, contrary to coliform, which was found resistant to those antibiotics with MIC values ranged between 0.38 and 128 μg/mL . Gentamycine (MIC values: Coliform, 0.125μg/mL; and Pseudomonas, 0.50 μg/mL), Tetracyclin (MIC values: Coliform, 1.00 μg/mL; and Pseudomonas, 0.75 μg/mL) and Streptomycine (MIC values: Coliform, 0.75 μg/mL; and Pseudomonas, 2.5 μg/mL) were also active against Coliform and Pseudomonas strains, while resistance to Vancomycine (no inhibition) was observed in the two strains