[Megalospermatocytes: degeneration of spermatocytes in aged human testis]

Megalospermatocytes are very large primary spermatocytes, which show a meiotic disorder in form of an asynapsis of the chromosomes. They appear as localized cell populations within the normal seminiferous epithelium and represent one or several clones of synchronously degenerating germ cells. The spatial extension of these megalospermatocyte populations is spherical to elliptical, some of them look like a section of a spiral around the longitudinal axis of the seminiferous tubule. Neighbouring megalospermatocyte populations in a segment of a seminiferous tubule show characteristic relative positions to each other: Their centers of gravity succeed one another in the longitudinal course of the tubule by distances of 40 to 85 micron. They are displaced against each other by angles between 120 degrees and 240 degrees around the longitudinal axis of the tubule. The centers of gravity of several megalospermatocyte populations, which follow each other in a segment of a tubule, show different distances from the basement membrane to the lumen of the tubule. The topographic arrangement of the megalospermatocytes in the human seminiferous epithelium obviously corresponds to an organization pattern, which is based upon the geometry of spirals, as it has been postulated for the normally proliferating seminiferous epithelium.