Utilization of [15N]glutamate by cultured astrocytes.

The metabolism of 0.25 mM-[15N]glutamic acid in cultured astrocytes was studied with gas chromatography-mass spectrometry. Almost all 15N was found as [2-15N]glutamine, [2-15N]glutamine, [5-15N]glutamine and [15N]alanine after 210 min of incubation.

[15N] leucine as a source of [15N] glutamate in organotypic cerebellar explants.

Approximately 26.0% of the [15N] glutamate and [alpha 15N] glutamine formed in organotypic cerebellar explants was derived from [15N] leucine. Approximately 14.

Preservation of brush border transport systems for proline and alpha-methyl-D glucoside from rat, dog, and human kidney.

The effects of freezing renal tissue from rat, dog, and man on the time course of uptake of proline and alpha-methyl-D-glucoside by subsequently isolated brush border membrane vesicles was examined and compared with uptake patterns by membranes isolated from tissue that had never been frozen. The overshoot phenomenon was used as the critical criterion for viability of the transport systems. Membranes isolated from frozen rat and dog kidney possessed intact transport systems for proline and alpha-methyl-D-glucoside capable of producing normal or even enhanced overshoot patterns.

Neuronal properties of neuroectodermal tumors in vitro.

Cell lines of medulloblastoma, retinoblastoma, and neuroblastoma, three childhood tumors derived from neuroectoderm, have been compared with respect to their neuronal properties. Neuroblastoma, a neural crest derivative, has been shown to express specific neuronal enzymes and the action potential sodium ionophore. Cell lines of medulloblastoma and retinoblastoma also express neuronal specific enzymes and therefore are considered to be of neuroblastic origin.

Isolation and characterization of a neuroblastoma cell line from peripheral blood in a patient with disseminated disease.

Circulation in the blood stream of neuroblastoma cells was confirmed by establishment of a cell line from the peripheral blood of a child with disseminated disease. The morphologic, enzymatic, and chromosomal pattern of this cell line was similar to a cell line established from the primary tumor on a previous occasion. The peripheral blood smear did not demonstrate tumor cells but increased numbers of atypical monocytes; lymphoblasts were evident, which may have been unrecognized neuroblasts.

Glycopeptides from the surgace of human neuroblastoma cells.

Glycopeptides suggesting a complex oligosaccharide composition are present on the surface of cells from human neuroblastoma tumors and several cell lines derived from the tumors. The glycopeptides, labeled with radioactive L-fucose, were removed from the cell surface with trypsin, digested with Pronase, and examined by chromatography on Sephadex G-50. Human skin fibroblasts, brain cells, and a fibroblast line derived from neuroblastoma tumor tissue show less complex glycopeptides.

Establishment and characterization of human neuroblastoma cell lines.

Three new tissue culture cell lines, CHP-100, CHP-126, and CHP-134, have been established from explant cultures of human neuroblastoma. The cell lines have been characterized with respect to morphology, chromosomes constitution, growth, neural enzyme content, and their ability to grow in nude mice. The cells grow as dense masses comprised of fibroblast-or neuroblast-like cells with small processes.

Comparison of the lipids of intracellular and extracellular rabies viruses.

The lipid composition of both intracellular and extracellular forms of the ERA strain of rabies virus grown in BHK/21 cells was determined. The lipids from purified preparations of both intracellular and extracellular virus yielded 57 and 58% neutral lipid, respectively. The phospholipids of the intracellular and extracellular virus constituted 43 and 42%, respectively.

Studies on antibody-producing cells. IV. Ultrastructue of plaque-forming cells of rabbit lymph.

Efferent lymph of the popliteal lymph nodes of rabbits was collected 4 days after a single footpad injection of SRBC. Thin-layer agar plating was done to isolate plaque-forming cells of the lymph for electron microscope examination, and the numbers of plaque-forming cells (PFC) in cells from the lymph and lymph nodes were determined. Of 71 PFC of lymph isolated and examined, 93% were lymphocytes, most of them with signs of substantial levels of physiologic activity.

Studies on antibody-producing cells. 3. Identification of young plaque-forming cells by thymidine- 3 H labeling.

Mice injected with sheep RBC and then, 4 days later with thymidine-(3)H, were sacrificed on the day of thymidine-(3)H injection or 1 or 2 days later. Hemolytic antibody plaque preparations were made of cells from the draining lymph nodes by a thin-plating procedure permitting collection of isolated PFC for electron microscopic examination and radioautography. Of cells obtained on the day of thymidine-(3)H injections, 65% of the labeled PFC were in the lymphocytic category, in comparison with 13% found previously in the entire population of such cells.

Studies on antibody-producing cells. II. Appearance of 3 H-thymidine-labeled rosette-forming cells.

A study of the kinetics of antibody-producing cells has been carried out by the use of rosette formation for detection of individual antibody-producing cells, and labeling with tritiated thymidine, in cells obtained from mouse spleens at intervals after injection of SRBC. Following a primary injection of the antigen, the number of RFC per million cells was found to increase to a peak at 5 days, then, after a decrease, to a second peak at about the 10th day. The curve of tritium labeling of RFC was also biphasic, with peaks on the 3rd and 7th day.

Studies on antibody-producing cells. I. Ultrastructure of 19S and 7S antibody-producing cells.

Antibody-bearing cells of spleen and lymph node of the mouse and rabbit detected by rosette formation with the antigenic red blood cells were collected by micropipet and studied by electron microscopy. More than 300 such cells were examined. In the lymph nodes, rosette-forming cells were all in the lymphocytic and plasmacytic categories.

Morphogenesis of the nucleoprotein of vesicular stomatitis virus.

Accumulation of the nucleoprotein of vesicular stomatitis virus (VSV) in the cytoplasm of BHK-21 cells and in two of four human cell lines was demonstrated. Appearance and progression of the nucleoprotein inclusions paralleled development of virus-specific immunofluorescence and production of virus progeny. The inclusions appeared early as discrete foci of filamentous material which eventually increased in size to form large masses which replaced normal cytoplasmic constituents.

Morphological aspects of the uptake of simian virus 40 by permissive cells.

After exposure of permissive cells to simian virus 40 (SV40), single particles were engulfed by the cell membrane and transported to the nucleus. The cell membrane closed tightly around the particles, increasing their diameter from 40 to 55 nm. The cell membrane was lost during interaction with the nuclear membranes, and particles of the original size were found in the nucleus 1 hr after infection.

Human cystinosis: intracellular deposition of cystine.

Membrane-limited inclusions were found in the cytoplasm of cells of the rectal mucosa, leukocytes, and cultured fibroblasts from two humans with cystinosis. Most of the inclusions contained amorphous material, presumably cystine. In cells of the rectal mucosa the material appeared frequently crystallized.