Figure 6: Three major groups of PVS cells revealed by various kinds of staining. (A and a) Unstained cross-sectional image of a PN slice with a thickness of 200 μm. Note the PN cells resembling a large round cell (arrow, 12.69 μm), a biconcave (flat)-shaped cell (open arrowhead, 7.42 μm), and a small round cell (arrowhead, 9.42 μm). (B–E) Typical cross-sectional images of the PN slice stained by H&E (B), Hemacolor (C), acridine orange (D), and toluidine blue (E). (b–e) Three groups of PN cells at a higher magnification displaying putative MCs (arrows), RBCs (open arrowheads), and WBC groups (arrowheads) which correspond to the neutrophils with lobulated nuclei. Note that the Hemacolor-stained PN slice clearly revealed the granules within putative MCs and isolated granules ((c), dotted circle). (D) and (d) are fluorescent microscopic images of acridine orange staining. (A)–(E) and (a)–(e) are images of different PVS tissues photographed at the same magnification. (F) Collection of three major groups of cells isolated from PVS tissue stained with Hemacolor. The individual PVS cells shown in ((F)-a1–a4) belong to the WBC group. WBC groups are composed of a plasma cell ((F)-a1)) with eccentrically placed nucleus, lymphocyte ((F)-a2)) with dense-staining nuclei and sparse cytoplasm, eosinophil ((F)-a3)) with eosinophilc cytoplasmic granules, and neutrophil ((F)-a4)) with multilobed nuclei and a lack of stained granules. The cells in ((F)-b) appeared in the group of normal mature RBCs. The cells shown in ((F)-c1–c3) are putative MCs (c1, typical (10–15 μm); c2, large (> 20 μm); and c3, elliptical type). (G) The cellular composition of the PVS. The PVS cells were counted from 25 fields (125 × 95 μm) in images of H&E staining of PVS ( ) at 1000x magnification.