[Karyotype analysis during development of chronic myelocytic leukemia].

We report cytogenetic data concerning 9 patients with chronica granulocytic leukemia and eosinophilia at the onset and during the chronic phase of the disease before the blastic crisis. The cariotype analises in the intermediate phases allowed to determine the first changes which could be involved in the evolutionary events of the disease up to the moment in which the typical markers of the blastic crisis can be found.

Effect of phosphatidylcholine vesicles on the activity of DNA polymerase-alpha.

Phosphatidylcholine vesicles stimulate the activity of the DNA polymerase-alpha from calf thymus. This effect is dependent upon the way of addition to the Mg ions, and the extent of the 3H-dTTP incorporation is closely related to the concentration of the vesicles. A role of phospholipids on the activity of the DNA-related enzymes is suggested.

H2B nucleohistone-phospholipid interactions. Thermal denaturation and ultrastructural analysis.

Sphingomyelin, phosphatidylserine, bovine lecithin and phosphatidylethanolamine modify the thermal stabilization of H2B-DNA complexes, by inducing stabilization at 0.3 and 0.6 H2B : DNA weight ratios and destabilify the arrangement of nucleohistone is confirmed by ultrastructural analysis which indicates a competitive action of these molecules during the nucleoprotein assembly.

Fine structure of the rabbit submandibular gland during the embryonic development.

The development of the submandibular gland has been examined in rabbit embryos from the 22nd day to the birth. The 2 main types of secretory cells, which synthetize dense serous granules or large pale mucous granules can be identified from the 24th day of development. A third type of cells, characterized by granules having different densities, has been identified in the preterminal tracts.

Mitochondrial and cytoplasmic ribosomes from mammalian tissues. Further characterization of ribosomal subunits and validity of buoyant-density methods for determination of the chemical composition and partial specific volume of ribonucleoprotein particles.

1. At 0-4 degrees C mitochondrial ribosomes (55S) dissociate into 39S and 29S subunits after exposure to 300mm-K(+) in the presence of 3.0mm-Mg(2+).

Chromatin phospholipids in normal and chronic lymphocytic leukemia lymphocytes.

Certain phospholipids are associated with the nonhistone chromosomal proteins extracted from normal B- and chronic lymphocytic leukemia lymphocytes. The ratio of phospholipids to nonhistone chromosomal proteins was constant with the different methods used for isolating nuclei and extracting the chromatin, although the various methods allowed a different recovery of total lipids from chromatin. Three phospholipids were extractable from the nonhistone protein fraction, but their respective ratios varied in chronic lymphocytic leukemia compared to normal B-lymphocytes.

Phospholipids bound to acidic nuclear proteins in human B and T lymphocytes.

Chromatin fractions (DNA, histones and non-histone chromosomal proteins NHCP) have been isolated from human peripheral B and T lymphocytes using different methods and analyzed in order to identify their lipid content. While DNA and histone fractions do not reveal the presence of lipids, a 2% of phospholipids is present in the NHCP fraction. The phospholipids associated with NHCP present a constant relative ratio among sphingomyelin, phosphatidyl-choline and phosphatidyl-ethanolamine both in B and T lymphocytes, whichever are the extraction procedures employed.

Chromosomal proteins in human B and T lymphocytes.

Histones and non-histone chromosomal proteins were characterized in B and T human lymphocytes by means of polyacrylamide disc gel electrophoresis. It was found that while histones do not present appreciable differences in the two examined populations, non-histone chromosomal proteins exhibit distinct electrophoretic profiles. Low molecular weight proteins predominate in B lymphocytes whereas high and intermediate proteins are largely represented in T lymphocytes.

The ultrastructure of the rabbit submandibular gland.

The secretory granules of the terminal and pre-terminal tracts of the rabbit submandibular gland display distinct features, while the cell morphology is quite similar. Among these cells, some smaller ones presenting an highly dilated endoplasmic reticulum have been identified in the pre-terminal tracts. Some hypothesis have been formulated concerning the function of these cells.

Ultrastructural aspects of BK virus uptake and replication in human fibroblasts.

After exposure of human embryonic fibroblasts to BK virus, virus particles adsorbed to the plasma membrane were engulfed by pinocytosis or captured by vesicles, possibly originating from the endoplasmic reticulum, within 2 h after infection. Most of the virus particles were then transported into lysosomes or into the nucleus, while a small amount of virus was found free in the cytoplasm. Virus particles entered the nucleus between 2 and 12 h after infection, were still detectable in the nucleus at 24 h after infectionand becamse morphologically undiscernible at 30 h after infection, suggesting that a nuclear uncoating mechanism was active between 24 and 30 h after infection.