Microspectrophotometric estimation of the desoxyribonucleic acid (DNA) content of individual normal and leukemic human lymphocytes.

photometry, a relationiship betweens nucleic acids and protein synthesis has l)een demonstrated, particularly with respect to rihonsucleic acid amid the myeloma plasma cell.’ . 2 Recently au important correlations between the chromosome usumber anid the 1)NA contenst of the cell nsucleus has been established.38 Th cellular DNA appears to be coisfined to the chromosomes, amid this quantity of DNA is believed to be a constant value in the insterphase diploid somatic nuclei of all tissues withins a species and is twice the amount of DNA presenst ins the haploid germ cell nuclei. Since the DNA constenst of the isucleus ins nonmitotic cells parallels the chromosome number, it gives ins practice a physicochemical measure of the chromosome isumber ins nsonmitotic, nionpolytense nuclei,9 especially when compared with the I)NA contenst of spermatids of the same species. While chemical determinations of the average DNA content per cell might be adequate ins tissues with a very low rate of mitosis and ins the absensce of nsuclear polyploidy, the true distributions of the DNA ins insdividual cells calsnsot be thus determined in mixed populationss of cells characterized by probable varyinsg rates of mitosis and abberations of mitosis as have been reported in the leukemias.’#{176} In the present study, microspectrophotometric determinsatiouss of Fetnlgens dye were employed to estimate the relative I)XA conteust of individual lymphocytes in smears from the blood, lymph nsodes, ausd boise marrow of nsormal subjects and patieists with acute aisd chronic forms of lymphocytic leukemia. Ins addition, impriusts from testes were made ins order to compare the DNA content of lymphocyte nuclei with that of haploid spermatid usuclei. Au evaluations was made of the significance of the findings in terms of receust advansces in cytogenetics.