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Biomedical subjects

G L Nicolson

Publications and source records attributed to G L Nicolson.

At least 19 recordsLinked to original sources
PubMed1979

Lectin-mediated agglutination of murine lymphoma cells. Cell surface deformability and reversibility of agglutination by saccharides.

Agglutination of S49 mouse lymphoma cells by Ricinus communis I agglutinin can be reversed by the competing haptenic saccharide, lactose, soon after agglutination, but after further incubation in the absence of lectin the agglutination reaction could not be reversed by lactose and the cells remained as multicell aggregates. The irreversibility of S49 cell agglutination was time, temperature and lectin concentration dependent and its onset correlated with ultrastructurally observed deformation of adjacent cell surfaces and an increase in the proportion of adjacent cell surface areas in close apposition within multicell aggregates. Pretreatment of S49 cells with cytochalasin B or cytochalasin B plus vinblastine enhanced R. communis I agglutinin-mediated agglutination, while vinblastine alone and fluoride plus azide had essentially no effect. When drug-treated cells were agglutinated and then incubated in lectin-free drug-containing media for various times prior to lactose addition, the drug effects were more pronounced. Cytochalasin B alone or with vinblastine inhibited lactose reversal of S49 cell agglutination compared to the drug-free controls, while fluoride plus azide enhanced hapten reversibility. Electron microscopic analysis revealed that the onset of agglutination irreversibility correlated with cell surface deformation in the drug-treated cells. Cell aggregates that were more readily reversible by lactose (fluoride plus azide) were unchanged or less deformed, while S49 aggregates treated with cytochalasin B plus vinblastine were more deformed compared to controls without drugs. These experiments suggest a role for cell surface deformability as an important secondary effect during lectin-mediated cell agglutination of S49 lymphoma cells.

Agglutination↗
PubMed1979

Selection of malignant melanoma variant cell lines for ovary colonization.

Murine melanoma line B16-F1, which shows some specificity for metastatic organ colonization of lung but rarely metastasizes to ovary, was used to select variant cell lines with increased preference for experimental ovary metastasis. Ovary-colonizing melanoma cell lines were sequentially selected in syngeneic C57BL/6 mice by repeated intravenous administration and surgical recovery of ovarian melanoma tumors for tissue culture. After ten selections for experimental ovary metastasis, line B16-010 was established which formed experimental metastatic ovary tumors in almost every test animal. In tissue culture B16-010 cells grew in circular colonies with rounded, smooth cell peripheries compared to B16-F1 cells which were flatter, grew in irregular patterns, and exhibited long cellular projections. Ovary-selected B16 lines contained less melanin pigment (B16-010 less than B16-05 less than B16-01 approximately equal to B16-F1) compared to the parental melanoma line. Together with previous cloning and selection data, these results are consistent with the preexistence of highly malignant cells in the parental tumor population that possess the ability to metastasize to specific organs.

Animals↗
PubMed1979

Retention of biologic characteristics of zona pellucida in highly concentrated salt solution: the use of salt-stored eggs for assessing the fertilizing capacity of spermatozoa.

When unfertilized hamster eggs are placed in highly concentrated solutions of neutral salts (e.g., 2 M ammonium sulfate), the egg proper, or vitellus, shrinks, creating a large perivitelline space; the zona pellucida remains unchanged in appearance under the light microscope. When these eggs are inseminated, many spermatozoa attach to and penetrate the zona. The specificity as well as several physical and chemical characteristics of the zona seem to remain unchanged during storage of the eggs in salt solutions. The properties of the human zona pellucida which allow the attachment and penetration of human spermatozoa are also retained in concentrated salt solutions. Shipment of salt-stored human eggs at ambient temperature to any part of the world is feasible and inexpensive. The present study suggests that salt-stored eggs can be used as substitutes for fresh living eggs in the preliminary assessment of fertilizing capacity of spermatozoa when collection of a large number of fresh unfertilized eggs, particularly in humans, is not practical.

Animals↗
PubMed1979

Interactions of tumor cells with vascular endothelial cell monolayers: a model for metastatic invasion.

The interactions of tumorigenic and nontumorigenic human and rodent cells with vascular endothelial cells and their underlying extracellular matrix were studied in culture. The abilities of various cells to attach to endothelial monolayers and cause morphologic changes, such as rupture of endothelial-endothelial cell interactions leading to retraction of endothelial cells and exposure of extracellular matrix, as well as their propensities to invade and underlap retracted endothelial monolayers and continue migration were assessed by time-lapse and phase-contrast microscopy as well as scanning and transmission electron microscopy. In general, highly malignant or highly invasive cells in vivo were capable of attachment, invasion, and migration under endothelial cells in vitro. This system may be useful for elucidating mechanisms of tumor cell arrest and extravasation.

Animals↗
PubMed1978

Lipopolysaccharide effects on sensitive and resistant variant Chinese hamster ovary cell lines.

Chinese hamster ovary (CHO . K1 . PRO) cell growth was inhibited by addition of a gram-negative bacterial lipopolysaccharide (LPS) to the cell culture medium. Growth inhibition began after three or four days of incubation, was dose-dependent up to a maximum at an LPS concentration of 500 microgram/ml and was accompanied by cell shape changes and enhanced cytoplasmic vacuolization. Formation of bizarre CHO . K1 . PRO cell shapes and vacuole formation were most pronounced after seven days of incubation with LPS and could be observed by light and electron microscopy. An LPS-resistant cell population was obtained by intermittent in vitro exposure to high levels of LPS; these variant cells or clones derived from them failed to display growth inhibition in the presence of LPS. A clone from the LPS-resistant variant population showed altered cell properties compared to the parental cell line which included changes in cell morphology, adhesion, and endocytosis. Parental cells was markedly density-inhibited, whereas the cariant clone exhibited considerable growth after confluency. The LPS-resistant variant cells showed a more elongated morphology than the parental line. No significant differences were observed between rates of detachment of parental and variant cells when sparse cultures of either line were removed from tissue culture dishes by ethylenediaminetetracetate (EDTA). However, at confluency approximately 100% of the variant cells versus 35% of the parental cells were removed by EDTA in one hour. Measurements of 125I-ferritin uptake by parental and variant cells showed approximately twenty-fold and twofold increases, respectively, in uptake induced by LPS when compared to untreated control cultures.

Animals↗
PubMed1978

Identification, localization, and role of fibronectin in cultured bovine endothelial cells.

We have examined bovine aortic endothelial cell cultures for the presence of fibronectin, a high molecular weight cell-surface glycoprotein. Sparse cultures contain fibronectin only on dorsal cell surfaces at regions of cell-cell contact, as detected by immunofluorescence. In contrast, when the endothelial cells reached confluence as a highly contact-inhibited monolayer, fibronectin was detected in an extracellular matrix underneath the cell monolayer but not on top of the monolayer. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis of isolated extracellular matrix revealed that a predominant component of the matrix is a protein of approximately 2.3 X 10(5) molecular weight, which has been identified as fibronectin.

Basement Membrane↗
PubMed1978

Dynamics of toxin and lectin receptors on a lymphoma cell line and its toxin-resistant variant using ferritin-conjugated, 125I-labeled ligand.

The dynamics of the toxin Ricinus communis agglutinin II (RCAII or ricin) on cells of a murine lymphoma line (BW5147) and a toxin-resistant variant line (BW5147RicR.3) that is 200 times more resistant than the parent to direct RCAII cytotoxicity were examined using ferritin-conjugated, affinity purified, 125I-labeled RCAII (ferritin-125I-RCAII). Ferritin-125I-RCAII was indistinguishable from native RCAII in quantitative binding and cytotoxicity experiments. When RCAII-sensitive BW5147 and -resistant BW5147RicR.3 cells were labeled with ferritin-125I-RCAII at various toxin concentrations (1--10 microgram/ml), no differences in toxin binding were observed. These same cells were examined by electron microscopy. At low ferritin-125I-RCAII concentrations (1-3 microgram/ml RCAII) where only the parental BW5147 cells were significantly more sensitive to RCAII, toxin receptors were internalized by ferritin-125I-RCAII-induced endocytosis. In parallel experiments, ferritin-125I-RCAII that bound to the resistant BW5147RicR.3 cells remained relatively dispersed or clustered, and there was little evidence of transport into cells via endocytosis. At higher ferritin-125I-RCAII concentrations (greater than 7 microgram/ml RCAII) where both parental and resistant variant cells are sensitive to the cytotoxic effects of RCAII, more ferritin-conjugated toxin was bound, and subsequent endocytosis occurred to a similar degree in both cell types. Endocytosis of ferritin-conjugated concanavalin A was indistinguishable on RCAII-sensitive parental and resistant variant cells at all concentrations tested. The results suggest that a specific defect on the selected BW5147RicR.3 cells prevents RCAII entry into these cells a low toxin concentrations, rendering them more resistant to the cytotoxic effects of RCAII.

Animals↗
PubMed1978

Characterization of the inhibitory effects of retinoids on the in vitro growth of two malignant murine melanomas.

The in vitro proliferation of murine melanoma cell lines S91 and B16 was inhibited by retinoic acid and retinyl acetate. The inhibitory effects were dependent on retinoid concentration and increased from 55 and 30% at 10(-9) M retinoic acid to 85 and 82% at 10(-5) M retinoic acid for S91 and B16 melanoma cells, respectively. S91 melanoma cells were more sensitive than B16 melanoma cells to inhibition by either retinoid, and both cell lines were more sensitive to retinoic acid than to retinyl acetate. When exposed to 10(-5) M retinoic acid, the two cell types grew at the same rate as did control cells for 48 hours, whereupon the growth rates of retinoid-treated cells decreased. After 6 days, the number of cells in control cultures increased 140 times (S91 melanoma cells) and 265 times (B16 melanoma cells), whereas retinoic acid-treated cells increased only 14 times (S91 melanoma cells) and 40 times (B16 melanoma cells). The degree of growth inhibition by retinoic acid was not dependent on initial cell density. Cortisone and hydrocortisone failed to prevent or reduce the inhibitory effect of retinoic acid; the release of lysosomal acid phosphatase was not increased and the intracellular level of 3',5'-cyclic AMP in cells grown for 5 days in the presence of 10(-5) M retinoic acid was not elevated. Viability of S91 and B16 cells after 8 days' exposure to 10(-5) M retinoic acid was similar to that in control cultures. The reduced growth rate of retinoic acid-treated cells reversed to the control rate 48-72 hours after removal of retinoic acid from the growth medium.

Animals↗
PubMed1978

Selection and biologic properties of malignant variants of a murine lymphosarcoma.

A syngeneic tumor model system with the RAW117 lymphosarcoma cell line was developed for use in investigations of host and tumor cell properties associated with an enhanced state of malignancy. This BALB/c mouse model was found to be similar to human lymphosarcoma in that liver and spleen were the major organs involved. Sequential in vivo selections were performed by iv tumor cell inoculation, removal of resulting solid liver tumor nodules for growth in vitro, and reinjection of the cultured cells iv. After ten such sequential selections for implantation, invasion, survival, and growth in liver, a lymphosarcoma cell line was obtained (RAW 117-H10) that formed approximately 200-fold more gross liver tumor nodules than did the parental tumor cell line in comparative biologic assays and displayed enhanced malignant properties when monitored by time of host death. Very few lung nodules or tumors were present at other sites with either the parental or any of the selected RAW117 lines, which confirms previous reports in which in vivo sequential selection yielded stable cell lines with preferential tumor colonization at specific sites.

Animals↗
PubMed1978

Specificity of arrest, survival, and growth of selected metastatic variant cell lines.

Animal tumor models for blood-borne metastasis have been developed by in vitro cloning or in vivo selection of malignant tumor cell populations to obtain organ-preferring variant tumor cell lines with altered arrest, survival, invasion, and growth properties. Selection and some tumor cell characteristics of lung-, brain-, and ovary-colonizing metastatic B16 melanoma, liver-colonizing RAW114 lymphosarcoma, and lung-colonizing MSV3T3 vasoformative sarcoma variant lines will be discussed along with additional data, suggesting that tumor cells of varying malignant potential preeexist in the unselected tumor population.

Animals↗
PubMed1978

Tumor cell and host properties affecting the implantation and survival of blood-borne metastatic variants of B16 melanoma.

The organ distribution, arrest and survival of [125I]5-iodo-2'-deoxyuridine-labeled B16 melanoma cells with low (B16-F1) or high (B16-F10) metastatic potential were studied in a variety of normal and immunosuppressed syngeneic C57BL/6 mice, allogeneic A mice, and athymic nude NIH Swiss mice and their immunocompetent littermates. In addition, the in vitro aggregation properties of these tumor cells with various host organ cells in suspension were examined. Tumor cell arrest and survival following i.v. injection occurred at significantly higher rates in normal mice than in immune-depressed animals irrespective of strain, and, two weeks later, significantly more tumor colonies were found in the normal animals. In syngeneic or allogeneic animals, B16-F10 cells were arrested, survived and formed significantly more gross pulmonary tumors than B16-F1 cells. B16-F10 cells also aggregated in vitro with purified organ cells in suspension obtained from either syngeneic or allogeneic mice at a greater rate than B16-F1 cells. These results indicate that although host properties can affect the arrest and survival of circulating tumor emboli, they do not diminish or abolish the biological differences between the high and low metastatic variant B16 lines.

Animals↗
PubMed1977

Activities of lectins and their immobilized derivatives in detergent solutions. Implications on the use of lectin affinity chromatography for the purification of membrane glycoproteins.

The effects of several commonly used detergents on the saccharide-binding activities of lectins were investigated using lectin-mediated agglutination of formalin-fixed erythrocytes and affinity chromatography of glycoproteins on columns of lectins immobilized on polyacrylic hydrazide-Sepharose. In the hemagglutination assays, Ricinus communis I (RCA1) and II (RCAII), concanavalin A (Con A), and the agglutinins from peanut (PNA), soybean (SBA), wheat germ (WGA), and Limulus polyphemus (LPA) were tested with several concentrations of switterionic, cationic, anionic, and nonionic detergents. It was found that increasing detergent concentrations eventually affected hemagglutination titers in both test and control samples, and the highest detergent concentrations not affecting lectin hemagglutinating activities were determined. The effects of detergents on specific binding of [3H]fetuin and asialo[3H]fetuin to and elution from columns of immobilized lectins were less severe when compared with lectins in solution, suggesting that the lectins are stabilized by covalent attachment to agarose beads. Nonionic detergents did not affect the binding efficiency of the immobilized lectins tested at concentrations used for membrane solubilization while cationic and zwitterionic detergents caused significant inhibition of Con A- and SBA-Sepharose activities. In sodium deoxycholate (greater than 1%) only RCAI-Sepharose retained its activity, whereas the activities of the other lectins were reduced dramatically. Low concentrations of sodium dodecyl sulfate (0.05%) inhibited only the activity of immobilized SBA, but at higher concentration (0.1%) and prolonged periods of incubation (16 h, 23 degrees C) most of the lectins were inactivated. These data are compared with previous reports on the use of detergents in lectin affinity chromatography, and the conditions for the optimal use of detergents are detailed.

Chromatography, Affinity↗