Meiosis in hematological malignancies.  In situ cytogenetic morphology. 
This is the first study on the in situ cytogenetic morphology and analysis of malignant bone marrow cells, growing attached on a culture vessel surface.  It was documented that bone marrow cells, in different types of hematological malignancies, divide by meiosis giving rise to a non-repetitive aneuploidy.  Male and female gametes are formed by meiosis and fertilization occurs in a life cycle of: [sequence see text] Immature and mature somatic oocytes were evidenced by prophase stages of the first and diploid or hypodiploid or haploid metaphases identical to those of the second human, ovarian oocytic meiotic division, showing "XX" or "XY" sex chromosomes in female or male patients respectively.  Nuclear vlimata were the male gametes showing a condensed head with tail morphology.  Metaphases of nuclear vlimata were aneuploid, keeping the head with tail shape, carrying chromosomes identical to those of human spermatogonia.  Somatic metaphases identical to those of human spermatocytes in meiosis II and spermatogonia were demonstrated.  The process of fertilization was documented by nuclear vlima invasion into host cell metaphases, by metaphases of fertilized oocyte showing both the female chromosome "0" and the male chromatids "s" and hybrid metaphases of oocytic with somatic chromosomes.  Meiosis was characterized by nuclear extrusion of chromosomes, meiotic, condensed chromosomes, nuclear vlimata, metaphase and nuclear fusion, hybrid metaphases, nuclear budding, nuclear conglomerates, nuclear bridges, chromosomal fusion substance, transfer of chromosomes and non-repetitive aneuploidy.  Meiotic, Double Minute, ring and minute chromosomes extruded by nuclei were loaded with glycoproteins, glycosaminoglycans and calcium-activated neutral proteinase, distinguishing them from mitotic chromosomes.  The main characteristic events of meiosis, observed in malignant bone marrow cells, were also demonstrated in fungal and rat testicular cells, known to divide by meiosis.