title: Karyometric and cytophotometric studies on nucleic acids in the culture of human lymphocytes with phytohemagglutinin.
abstract: Lymphocyte transformation with phytohemagglutinin (PHA) was analyzed by karyometry and cytophotometry of single cells. The former showed the distribution of various-sized transforming cells, and the latter the increase of DNA and RNA. Two different types of karyograms were obtained; one with three peaks corresponding to 2c, 4c, and 8c, and the other with only a 2c peak. Although small in number (8%), karyometry showed that DNA synthesis took place in the extremely early stage of transformation, 1 h after stimulation with PHA, which was proved by cytophotometry and ultrastructural findings. An increasing curve of DNA and RNA revealed that a lymphocyte continued to enlarge from 2c to 4c and divide again through the normal cell cycle in a suitable condition. The largest blast cell, a polyploid cell, may be induced by the lack of a sufficient amount of RNA and protein in need of cell division, and may be a degenerative cell in the strict sense. Among the large cells with blastlike appearance, there were a considerable number of so-called degenerative cells with a low amount of DNA. The ratio of RNA to DNA increased steeply in the actively DNA synthesizing S phase, which supports the morphologic findings of blast cell, the appearance of basophilic cytoplasm, and active-looking nucleoli.
mesh_terms: D000293:Adolescent; D000328:Adult; D002455:Cell Division; D002466:Cell Nucleolus; D006801:Humans; D007620:Karyometry; D037102:Lectins / Q000494:pharmacology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000032:analysis / Q000187:drug effects*; D008297:Male; D009696:Nucleic Acids / Q000032:analysis*; D010783:Photometry; D013997:Time Factors
chemical_list: D037102:Lectins; D009696:Nucleic Acids