Description of primordial germ cells, oogonia, oocytes and embryo-like growth in squash preparations of tissues from hematological malignancies.

This study evidences the presence of primordial germ cells, in tissue squash preparations and sections from hematological malignancies. Primordial germ cells were identified by their morphology, the intense PAS, PAS-D reaction and presence of calcium-activated neutral proteinase. Primordial germ cells gave rise to nuclear vlimata. Immature oogonia exhibited a nuclear envelope and a star-shaped nuclear core, arising from acellular globose bodies impregnated by a nuclear vlima of primordial germ cell. Bone marrow tissue oogonia were PAS and PAS-D positive, identical to fungal ones. Calcium-activated neutral proteinase was demonstrated in the plasma of the acellular globose bodies, the nuclear envelope and the conglomerated primordial germ cells. Immature bone marrow oogonia progressed into mature ones, leptotene, diplotene, dictyotene and mature oocytes. Nuclear vlimata fertilized primordial germ cells, oogonia and oocytes, giving rise to round embryos at the morula and hatching morula-like stages. Embryos consisted of a zonapellucida-like cortex, composed of glycosaminoglycans, glycoproteins, protease and diffuse nuclear material, enclosing developing cells. Primordial germ cells, oogonia and embryos were also demonstrated in squash preparations of adult rat testis and sections of normal rat bone marrow tissues. The observations document that primordial germ cells are the primary stem cells which give rise to nuclear vlimata and oogonia, which constitute the secondary stem germ cells. The results are discussed in terms of stem cell renewal according to the events: primordial germ cells-gametes-fertilization-embryos-primordial germ cells.