Cytology of oomycetes

Evidence is presented for gametangial meiosis in six Oomycetes. Particular attention is drawn to late meiotic prophase stages (pachytene-diplotene) in which chromomeres and paired homologues can be seen. One of these Oomycetes has been shown to have an abortive meiosis. Multiple chromosome associations (quadrivalent configurations, with some trivalent and univalent configurations) at first metaphase with unequal divisions at first telophase or second metaphase suggest that autopolyploidy is to be found in several species. Allopolyploidy is suspected at intermediate levels of ploidy. Basic chromosome numbers of n=3 for Achlya and n=10 for Pythium are proposed.     

Cytology of hemangioendothelioma

The cytologic appearance is described of hemangioendothelioma in fine needle aspiration smears from a young male who presented with recurring bilateral lesions within two years. The cytomorphologic pattern was extremely cellular, with a monomorphic population of cells, some of which showed a tendency to form rosettelike or pseudoacinar formations.