At p.n. Day 10 (stage II), although the FACS pattern seemed unchanged in both the FSC-H and the FL2 parameters, the constant portion of 4d cells (~3%)—despite thegreatlyre-duced frequency of mitotically dividing somatic cells—is consistent with cells of the first spermatogenic wave reaching the leptotene stage of prophase I. There are no R1 cells (in the first window) in this developmental stage, since lep-totene spermatocytes are small cells. As the developmental process progresses, more cells from the first spermatogenic wave enter prophase I. buy levaquin online

As a result, by p.n. Day 12 (stage III), when zygotene cells are first seen, a significant number of cells exhibit FSC-H values appropriate for the R1 subpopulation, although they do not appear as a discrete group. Additionally, a statistically significant increase in the proportion of 4d cells is observed. The progress of cells from the first spermatogenic wave to the early and late pachytene stages (stages IV and V) is characterized by a well-defined R1 group at p.n. Day 14 and acquisition of the R2 subpopulation at p.n. Days 17-18, respectively. Haploid round spermatids first appear (group R6) at p.n. Days 20-21 (stage VI) as expected, and elongating spermatids become apparent by p.n. Days 24-25 (R7, stage VII), whereas elongated condensed spermatids are apparent (R5) from p.n. Day 27-28 (stage VIII).