Modulated Raman spectroscopy for enhanced identification of bladder tumor cells in urine samples.

Standard Raman spectroscopy (SRS) is a noninvasive technique that is used in the biomedical field to discriminate between normal and cancer cells. However, the presence of a strong fluorescence background detracts from the use of SRS in real-time clinical applications. Recently, we have reported a novel modulated Raman spectroscopy (MRS) technique to extract the Raman spectra from the background. In this paper, we present the first application of MRS to the identification of human urothelial cells (SV-HUC-1) and bladder cancer cells (MGH) in urine samples. These results are compared to those obtained by SRS. Classification using the principal component analysis clearly shows that MRS allows discrimination between Raman spectra of SV-HUC-1 and MGH cells with high sensitivity (98%) and specificity (95%). MRS is also used to distinguish between SV-HUC-1 and MGH cells after exposure to urine for up to 6 h. We observe a marked change in the MRS of SV-HUC-1 and MGH cells with time in urine, indicating that the conditions of sample collection will be important for the application of this methodology to clinical urine samples.

Strawberry polyphenols are equally cytotoxic to tumourigenic and normal human breast and prostate cell lines.

The cytotoxic effects of strawberry polyphenols were investigated on normal cells and tumour cells derived from the same patient. A human prostate epithelial cell line (P21) and two tumour cell lines (P21 tumour cell line 1 and 2) derived from the same patient, and a normal human breast epithelial cell line (B42) and a tumour line derived from it (B42 clone 16) were used. A polyphenol-rich extract derived from strawberry or anthocyanin or tannin-rich sub-fractions were applied to the cell lines in doses varying from 50 to 1.5 microg/ml. The strawberry extract was cytotoxic with doses of approximately 5 microg/ml causing a 50% reduction in cell survival in both the normal and the tumour lines. The extracts were also cytotoxic to peripheral blood human lymphocytes stimulated with phytohaemagglutinin but higher levels (>20 microg/ml for 50% reduction in cell survival) were required. After fractionation of the strawberry sample, the cytotoxicity was retained in the tannin-rich fraction and this fraction was considerably more toxic to all cells (normal or tumour cell lines or lymphocytes) than the anthocyanin-rich fraction. Established prostate (LNCaP and PC-3) and breast (MCF-7) tumour cell lines were more resistant to the strawberry extract with concentrations of 50 microg/ml required for 50% reduction in cell survival, which is similar to levels in previous studies on the antiproliferative effects of berry extracts. Although these concentrations are much greater than possible physiological levels, they are comparable to those reported in other studies. From these findings, we conclude that there is little evidence to assume that polyphenols from strawberry have a differential cytotoxic effect on tumour cells relative to comparable normal cells from the same tissue derived from the same patient.

Passive optical separation within a 'nondiffracting' light beam.

A passive, optical cell sorter is created using the light pattern of a 'nondiffracting' beam-the Bessel beam. As a precursor to cell sorting studies, microspheres are used to test the resolution of the sorter on the basis of particle size and refractive index. Variations in size and, more noticeably, refractive index, lead to a marked difference in the migration time of spheres in the Bessel beam. Intrinsic differences (size, refractive index) between native (unlabeled) cell populations are utilized for cell sorting. The large difference in size between erythrocytes and lymphocytes results in their successful separation in this beam pattern. The intrinsic differences in size and refractive index of other cells in the study (HL60 human promyelocytic leukaemic cells, murine bone marrow, and murine stem/progenitor cells) are not large enough to induce passive optical separation. Silica microsphere tags are attached to cells of interest to modify their size and refractive index, resulting in the separation of labeled cells. Cells collected after separation are viable, as evidenced by trypan blue dye exclusion, their ability to clone in vitro, continued growth in culture, and lack of expression of Caspase 3, a marker of apoptosis.