A microgravimetry apparatus is described which utilizes osmotically-balanced Percoll gradients produced by a computer-driven low pressure gradient system. A plexiglass reservoir was designed to minimize parallax artifacts while allowing repeated measurements and easy retrieval of groups of 20 samples. This system provides inert and nontoxic gradients with profile flexibility, reproducibility, a...

A discontinuous gradient of Percoll was used to remove RBCs from polymorphonuclear leucocyte (PMN) preparations. The resulting red blood cell-free preparation was used to investigate the effect of ammonium chloride on the iodination response of human PMN. Treatment of PMN with ammonium chloride for five minutes at room temperature resulted in a statistically significant increase in the iodinati...

The isolation of Cowdria ruminantium by means of Percoll density gradient centrifugation permits the recovery of partially purified viable populations of the organism possessing distinctly different densities. These conclusions are based upon results of analyses of density fractions by intravenous inoculation into sheep, protein determination, electron microscopy and enzyme-linked immunosorbent...

Nuclei isolated from embryos of wheat (var. Yamil) incorporated I3HIUTP into a trichioroacetic acki-insoluble product linearly for 60 minutes. When the RNA synthesized in vitro was analyzed on a sucrose gradient, the amount of RNA in the 4S region increased with longer incubation times. These data and the absence of higher molecular weight RNA of specific size classes in our work (and previousl...

Nuclei isolated from embryos of wheat (var. Yamil) incorporated I3HIUTP into a trichioroacetic acki-insoluble product linearly for 60 minutes. When the RNA synthesized in vitro was analyzed on a sucrose gradient, the amount of RNA in the 4S region increased with longer incubation times. These data and the absence of higher molecular weight RNA of specific size classes in our work (and previousl...

The purpose of this work was to study the isolation and a light microscopy technique for cultured lymphocytes. Blood samples were obtained by venipuncture with an anticoagulant added and centrifuged in a Percoll density gradient to separate the leukocytes. Lymphocytes were placed in 25 cm tissue culture flasks at 37°C. After culturing, they were fixed and stained with the methods used for blood...

Human bone marrow was separated on continuous Percoll density gradients to analyze the distribution of cells of the megakaryocytic lineage. Megakaryocytes were identified by indirect immunofluorescence using a monoclonal antibody (LJP4) specific to the glycoprotein IIb/IIIa (GPIIb/IIIa) complex of platelets. Neither endothelial cells nor monocytes expressed the epitope identified by this antibo...