title: Megalospermatocytes: indicators of disturbed meiosis in man.
abstract: Megalospermatocytes are degenerating primary spermatocytes which do not develop any further than to leptotene stage of the prophase of meiosis. In histological sections they are prominent because of their size (approximately 24 microns in diameter). The nucleus of a megalospermatocyte presents single strands of chromosomes only. The cytoplasm contains extremely widened vesicles and cisternae of the ER which are filled with a finely granular electron dense material. Megalospermatocytes may appear singular in small groups in the testis tissue of young men with varying fertility disturbances. They are relatively frequent in testis tissue of men older than 65 years. Here they represent a special form of a rest of spermatogenetic activity in the germinal epithelium.
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008540:Meiosis; D008854:Microscopy, Electron; D012671:Seminiferous Tubules / Q000473:pathology; D013094:Spermatozoa / Q000002:abnormalities* / Q000166:cytology / Q000648:ultrastructure