Andersen A.Z.,University of Southern Denmark |
Duelund L.,Memphys |
Brewer J.,Memphys |
Brewer J.,Membrane Biophysics and Biophotonics Group |
And 8 more authors.
Food Biophysics | Year: 2011
Traditionally, the effects and efficiency of food surface decontamination processes, such as chlorine washing, radiation, or heating, have been evaluated by sensoric analysis and colony-forming unit (CFU) counts of surface swabs or carcass rinses. These methods suffice when determining probable consumer responses or meeting legislative contamination limits. However, in the often very costly, optimization process of a new method, more quantitative and unbiased results are invaluable. In this study, we employed a biophysical approach for the investigation of qualitative and quantitative changes in both food surface and bacteria upon surface decontamination by SonoSteam ®. SonoSteam ® is a recently developed method of food surface decontamination, which employs steam and ultrasound for effective heat transfer and short treatment times, resulting in significant reduction in surface bacteria. We employ differential scanning calorimetry, second harmonics generation imaging microscopy, two-photon fluorescence microscopy, and green fluorescence protein-expressing bacteria and compare our results with those obtained by traditional methods of food quality and safety evaluations. Our results show that there are no contradictions between data obtained by either approach. However, the biophysical methods draw a much more nuanced picture of the effects and efficiency of the investigated decontamination method, revealing, e. g., an exponential dose/response relationship between SonoSteam ® treatment time and changes in collagen I, and a depth dependency in bacterial reduction, which points toward CFU counts overestimating total bacterial reduction. In conclusion, the biophysical methods provide a less biased, reproducible, and highly detailed system description, allowing for focused optimization and method validation. © 2011 Springer Science+Business Media, LLC.
Csonka A.,University of Szeged |
Spengler G.,University of Szeged |
Martins A.,University of Szeged |
Martins A.,New University of Lisbon |
And 7 more authors.
In Vivo | Year: 2013
Background: Cancer cells become refractory to chemotherapy as a consequence of their overexpression of multidrug transporters. Materials and Methods: The anticancer and multidrug resistance (MDR) reversal effects of the racemic form and the two enantiomers of thoridazine were investigated on a mouse T-lymphoma cell line overexpressing the ATP-binding cassette, subfamily-B (MDR/TAP), member 1 (ABCB1) transporter (also known as P-glycoprotein) and on human PC3 prostate cancer cell line by 3-(4.5-dimethylthiazolyl-2)-2.5-iphenyl tetrazolium bromide (MTT) assay. The modulation of ABCB1 transporter activity was studied by rhodamine123 accumulation, the apoptosis-inducing effect was investigated using fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide. Results: The thioridazine racemic and (+) and (-) enantiomers were similarly effective. Drug accumulation by MDR mouse T-lymphoma cells was moderately modified in the presence of thioridazine derivatives. Thioridazine induced apoptosis of the MDR cancer cell line, but there was no significant apoptotic effect on the PC3 cell line. Conclusion: Apparently, the chirality of thioridazine has no importance in the inhibition of MDR phenotype of cancer cells.