Human papovavirus in Papanicolaou smears of urinary sediment detected by transmission electron microscopy.

A technique is described whereby inclusion-bearing cells identified by light microscopy in stained smears of urinary sediment were reprocessed for examination in the electron microscope. The nuclei of the abnormal cells were found to contain numerous virus particles, 35 nm in diameter, which morphologically resembled papovaviruses. The technique was applied in this case to identify further the virus producing the cytopathic changes in the Papanicolaou smear. It could be particularly valuable for retrospective studies of mounted cytological or histological material when suitable specimens are no longer available for virological investigation.