Single histogram method

Fig. 9.4.7 Electron microscopic images of Mg small particles prepared by different methods and their size histograms. (A) Mg fine powders produced by a conventional gas-evaporation method with Ar at 4 kPa. (B) Mg fine particles produced by a matrix isolation method with Ar at 300 Pa in tetrahydrofuran. (C) Mg ultrafine particles produced by a matrix isolation method with He at 1.3 kPa in tetrahydrofuran. The scale bar for (C) is the same as for (B). Abscissa at top (n) is a rough estimate of the number of Mg atoms in a single particle whose diameter is represented by logarithm of diameter (nm) in the bottom scale. Ordinate (N ) is a normalized number of particles in a unit size width. (From Ref. 4.)...

It is possible to permeabilize the outer membrane of normal cells (with detergent or alcohol) in order to allow propidium iodide to enter the nuclei. If we then treat the normal cells with RNase in order to ensure that any fluorescence results from their DNA content (without a contribution from double-stranded RNA), we find that the nuclei fluoresce red with an intensity that is more or less proportional to their DNA content. By the use of a red filter and a linear amplifier on the photomultiplier tube, we can detect that red fluorescence. The channel number of the fluorescence intensity will be proportional to the DNA content of the cells. The method is simple and takes about 10 minutes. Flow cytometric analysis of the red fluorescence from the particles in this preparation of nuclei from normal, nondividing cells will result in a histogram with a single, narrow peak (see the first histogram in Fig. 8.1) all the particles emit very nearly the same amount of red fluorescence. This supports our knowledge that all... 

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