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SummaryObjective-Our objective was to compare the physiochemical properties and erosion potentials between beverages available in the UK and the US.Methods-The physiochemical properties (pH, titratable acidity and fluoride concentration) and erosion potential on enamel surfaces of beverages available in the UK were compared to similar beverages from the US. Enamel windows were exposed to beverages for 25 hours. Teeth were sectioned through the windows, and lesion depths were defined as the average distance between the original tooth structure and the base of demineralization.Results-The pH was lower in UK apple juice, orange juice, Diet Pepsi® and Sprite Zero® (p<0.05), and higher in UK orange soda and diet orange soda than in similar US beverages (p<0.05). Titratable acidities were higher in UK apple juice, orange juice, orange soda, diet orange soda and Sprite® (p<0.01), and lower in UK Sunny D® than in the US counterpart (p<0.001). Fluoride concentrations were lower in UK apple juice, orange juice, Coke®, and Diet Coke®, Sprite® and Sprite Zero® (p<0.001), and higher in UK orange soda, diet orange soda, Pepsi® and Diet Pepsi® than in their US counterparts (p<0.001). Lesion depths were higher in UK apple juice, orange juice, Diet Coke®, Sprite® and Sprite Zero® than in their US counterparts (p<0.05). Lesion depths were associated with pH (p=0.010) and country of origin (p=0.002).

A noninvasive method of prenatal genetic diagnosis requires fetal cell selection from the maternal circulation that allows efficient recovery for analysis by fluorescence in situ hybridization (FISH). We have solved several problems that negatively affect the isolation and FISH analysis of fetal nucleated red blood cells (nRBCs) in the maternal circulation. The use of glycophorin A (Gly A) antibodies (Abs) for selection is problematic because all five monoclonal antibodies (mAbs) tested caused agglutination of non‐nRBCs, thereby changing both light scatter and fluorescence properties of cells by flow cytometry. Because the number of non‐nRBCs is variable after Ficoll separation, isolation of nRBCs could be compromised severely by agglutination of nucleated cells with nonnucleated cells, causing them to shift light scatter and fluorescence properties. Several methods for the removal of unwanted maternal white blood cells with CD45 mAbs were also evaluated. Magnetic bead depletion was found to interfere with FISH detection because of residual bead debris after sorting. By contrast, removal of CD45+ cells by a panning technique eliminated this problem. Positive selection methods based on CD71, CD45, and LDS‐751 staining and detection of fetal cells by gamma globin expression were also analyzed. Fetal cells were detected by FISH in 11 of 19 (CD71 selection) and in 13 of 15 (gamma selection) random pregnancies. These data support the possibility of a noninvasive method for isolation and analysis of fetal cells for prenatal diagnosis. © 1996 Wiley‐Liss, Inc.

No abstract

A noninvasive method of prenatal genetic diagnosis requires fetal cell selection from the maternal circulation that allows efficient recovery for analysis by fluorescence in situ hybridization (FISH). We have solved several problems that negatively affect the isolation and FISH analysis of fetal nucleated red blood cells (nRBCs) in the maternal circulation. The use of glycophorin A (Gly A) antibodies (Abs) for selection is problematic because all five monoclonal antibodies (mAbs) tested caused agglutination of non-nRBCs, thereby changing both light scatter and fluorescence properties of cells by flow cytometry. Because the number of non-nRBCs is variable after Ficoll separation, isolation of nRBCs could be compromised severely by agglutination of nucleated cells with nonnucleated cells, causing them to shift light scatter and fluorescence properties. Several methods for the removal of unwanted maternal white blood cells with CD45 mAbs were also evaluated. Magnetic bead depletion was found to interfere with FISH detection because of residual bead debris after sorting. By contrast, removal of CD45+ cells by a panning technique eliminated this problem. Positive selection methods based on CD71, CD45, and LDS-751 staining and detection of fetal cells by gamma globin expression were also analyzed. Fetal cells were detected by FISH in 11 of 19 (CD71 selection) and in 13 of 15 (gamma selection) random pregnancies. These data support the possibility of a noninvasive method for isolation and analysis of fetal cells for prenatal diagnosis.