Retinoid-sensitive cells and cell lines.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
B Amos
Publications and source records attributed to B Amos.
DNA fingerprinting: a new dimension.
Explore the source record for details and available documents.
Alleles↗
Modulation by all-trans retinoic acid of glycoprotein glycosylation in murine melanoma cells: enhancement of fucosyl- and galactosyltransferase activities.
beta-All-trans retinoic acid (RA) treatment of murine S91-C2 melanoma cells decreases in vitro growth and modulates the glycosylation of specific cellular and cell-surface glycoproteins. The effect of RA treatment on [3H]fucose, [3H]galactose, and [3H]glucosamine incorporation was investigated by metabolic labeling followed by analysis of labeled cellular glycoproteins using polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS-PAGE) and fluorography. RA treatment dramatically increased the incorporation of the labeled monosaccharides into one glycoprotein of Mr 160,000 (gp160), which has been previously implicated in the growth-inhibitory effect of RA on these cells. Following RA treatment, cell-surface sialic acid residues on gp160 were also more intensely labeled by NaIO4 oxidation and subsequent NaB[3H]4 reduction than were those on gp160 of untreated cells. The activities of fucosyl- and galactosyltransferase increased about 1.5 to 1.9 times after RA treatment. These results suggest that the increased activities of the two glycosyltransferases is responsible for the increased incorporation of fucose and galactose into gp160.
Animals↗
Modulation of growth, differentiation and glycoprotein synthesis by beta-all-trans retinoic acid in a multicellular tumor spheroid model for squamous carcinoma of the head and neck.
Cell line MDA 886Ln was established from a laryngeal lymph node metastasis. When grown as a multicellular tumor spheroid (MTS), it exhibits squamous differentiation. We studied the effects of beta-all-trans retinoic acid (RA) on the growth, differentiation and glycoprotein content of this MTS model for squamous carcinomas of the head and neck. The growth of MTSs was inhibited in a dose-dependent manner by 10(-6) to 10(-10) M RA. Growth inhibition occurred between 3 and 5 days of RA treatment (10(-6)M). Immunohistochemical and electrophoretic analyses revealed that RA suppressed the morphological markers of squamous differentiation (squames), involucrin expression, and keratin expression. Gly-coprotein expression was examined by metabolic labelling using 3H-glucosamine, in situ labelling of polyacrylamide gels with 125I-labelled wheat-germ agglutinin (WGA), localization of fluorescein isothionate-WGA in frozen sections, and determination of sialyltransferase activity. Treatment using 10(-6) M RA altered glycoprotein expression both biochemically and morphologically, and WGA was shown to bind preferentially to sialic acid residues. The sensitivity of this MTS model to RA treatment and its ability to be analyzed through morphological, immunohistochemical and biochemical techniques suggest that it will prove useful in studying the relationships between growth, differentiation and RA-induced alterations in squamous carcinomas.
Carcinoma, Squamous Cell↗
Enhancement of sialyltransferase in two melanoma cell lines that are growth-inhibited by retinoic acid results in increased sialylation of different cell-surface glycoproteins.
Previous studies have demonstrated the ability of retinoic acid (RA) to inhibit the growth of two spontaneous murine melanoma cell lines (B16-F1 and S91-C2) and to augment both sialyltransferase activity and the sialylation of an Mr 160,000 cell-surface glycoprotein. The present study examined the effects of RA on an ultraviolet irradiation-induced murine melanoma cell line K-1735P. Like the two spontaneous melanomas, the uv-induced melanoma exhibited susceptibility to the growth-inhibitory action of RA. Both the anchorage-dependent and the anchorage-independent growths of the K-1735P cells were suppressed by RA, with IC50 values of 5 X 10(-9) and 3 X 10(-12) M, respectively. Sialyltransferase activity in both S91-C2 and K-1735P cells treated with 10(-6) or 10(-5) M RA increased two- and three-fold, respectively, as compared with untreated cells. In contrast, cell-surface sialo- and galactoglycoproteins, revealed by labeling with periodate and tritiated borohydrate or with neuraminidase, galactose oxidase, and tritiated borohydrate, respectively, varied between the S91-C2 and the K-1735P cells, and each cell line's modulation by RA was also distinct. These findings suggest that although RA can increase the activity of sialyltransferase in different melanoma cells, this increased activity may, in turn, result in an increased sialylation of distinct cell-surface glycoproteins.
Animals↗
Heparin-binding properties of human serum spreading factor.
Human serum spreading factor (SF) is a blood glycoprotein that promotes attachment and spreading and influences growth, migration, and differentiation of a variety of animal cells in culture. SF purified from human plasma or serum by chromatographic methods reported previously (Barnes, D. W., and Silnutzer, J. (1983) J. Biol. Chem. 258, 12548-12552) does not bind to heparin-Sepharose under conditions of physiological ionic strength and pH. In a further examination of the heparin-binding properties of human serum SF, we found that exposure of purified SF to 8 M urea altered several properties of the protein, including heparin affinity, and these alterations remained after removal of the urea from SF solutions. Urea-treated SF bound to heparin under physiological conditions, and salt concentrations of 0.4 M or higher were required for elution of urea-treated SF from heparin-Sepharose at pH 7.0. The alteration of heparin-binding properties of SF also was observed upon exposure of the protein to heat or acid. Treatment of SF with urea, heat, or acid resulted additionally in greatly decreased cell spreading-promoting activity of the molecule. The decreased biological activity was associated with a reduced ability of the treated SF to bind to the cell culture substratum, a prerequisite for the attachment-promoting activity of the molecule. Experiments examining the heparin-binding properties of native SF in unfractionated human plasma indicated that the major portion of SF in blood did not bind to heparin under conditions of physiological ionic strength and pH.
Blood Proteins↗
Glass-bead affinity chromatography of cell attachment and spreading-promoting factors of human serum.
The glass-binding properties of a number of purified glycoproteins capable of promoting attachment and spreading of a variety of types of animal cells in culture have been examined. Two such factors in human serum, fibronectin and serum spreading factor, exhibited strong affinities for glass beads and could be eluted from glass-bead columns under similar conditions. A number of other glycoproteins of human serum that do not promote cell adhesion did not bind to glass beads under conditions that resulted in binding of serum spreading factor or fibronectin. At a sufficiently low ratio of serum volume to glass-bead volume, human serum could be simultaneously depleted of serum spreading factor, fibronectin, and cell spreading-promoting activity by glass-bead affinity chromatography. Laminin, another cell spreading-promoting glycoprotein, possessed glass-binding properties similar to those of serum spreading factor and fibronectin while chondronectin, a fourth cell spreading-promoting factor of more limited specificity of biological activity and distribution in vivo, did not exhibit a strong interaction with glass beads under the same conditions. These observations suggest that glass-bead column affinity chromatography may prove useful as a general method for isolation and study of glycoprotein factors promoting attachment and spreading of cells in culture.
Animals↗
HLA in two islands of French Polynesia.
The HLA-A, B, and C antigens of 243 individuals from two Polynesian islands, Maiao and Hiva Oa, have been characterized. 328 haplotypes were defined by family analysis. Most frequent antigens were A2, A11, Aw24, A26 , Aw34 ; Bw38, Bw39 , Bw48 , Bw55 , Bw56 , Bw60 ; Cwl, Cw3, and Cw4. Several other antigens were present at low frequency or were present on only one island. New variants of Bw22 and B40 were found. Despite an overall similarity in antigens of the two islands, the combination of HLA-A, B and C antigens on the haplotype were distinctive. Of 328 total haplotypes identified, 65 were unique. Thirteen of these (20%) were present on both islands. Twenty-eight (43%) were unique to Hiva Oa and 24 (37%) were unique to Maiao . Significant, positive linkage disequilibrium values (delta) for HLA-A, B and HLA-B, C antigens were also different for the two populations.
Alleles↗
Quantitative determination of naproxen in formulated rat feed by gas chromatography-mass spectrometry and gas chromatography-flame-ionization detection.
Explore the source record for details and available documents.
Animal Feed↗
High-performance liquid chromatographic measurement of cloprednol in human plasma.
A rapid and specific high-performance liquid chromatographic method for the quantitative determination of cloprednol in human plasma is described. Samples were extracted using methylene chloride-ether (40:60) and then purified further by solvent and pH partitioning techniques. Cloprednol was analyzed using normal-phase chromatography and UV detection at 254 nm. The final recovery after losses during the cleanup procedure for cloprednol from human plasma was 80.8%. The lowest concentration that could be measured with confidence was 8 ng/ml.
Chromatography, High Pressure Liquid↗
Genetic studies on the Ticuna, an enigmatic tribe of Central Amazonas.
The Ticuna are an Amerindian tribe of Central Amazonas, a key location in theories of the peopling of eastern South America. The results of typing some 1760 members of the tribe with respect to 37 different genetic systems are reported, as are the results of HLA typings on a subsample of 129 persons. Salient findings include the following. (1) Except for a high frequency of LMs allele and an unusual combination of HLA allele frequencies, there are no notable findings with respect to the commonly studied polymorphic systems. A multivariate treatment of six of the most commonly studied genetic polymorphisms accords the Ticuna an 'average' position among Amerindian tribes. (2) There is much less intervillage heterogenicity than usually encountered in Amerindian tribes; this is attributed to recent high rates of intervillage migration due to religious developments. (3) A thus-far unique polymorphism of ACP1 was identified, the responsible allele having a frequency of 0.111. (4) In proportion to the size of the tribe, there was a relative paucity of 'private' genetic variants, the ACP1 allele being the only one. This discrepancy is attributed to a relatively recent numerical expansion of the tribe; effective population size over the past several thousand years is thought to have been well below what present numbers would suggest. (5) The thesis is again advanced that 'private variants' (alleles not occurring as polymorphisms of wide distribution) are more common in Amerindian than in Caucasian or Japanese populations.
Alleles↗
Genetic linkage between hereditary hemochromatosis and HLA.
A large Mormon pedigree of a proband with hemochromatosis was studied, using transferrin saturation as the quantitative phenotypic trait. The analysis indicated that the inheritance of hemochromatosis was recessive, with partial expression in some heterozygotes. The lod score of 6.88 (theta = .0) was strongly indicative of linkage between the hemochromatosis locus and the human major histocompatibility (HLA) loci.
Chromosome Mapping↗
Quantitative determination of prednisone and prednisolone in human plasma using GLC and chemical-ionization mass spectrometry.
A method for the quantitative determination of prednisolone and prednisone in human plasma utilizing GLC and chemical-ionization mass spectrometry is described. Corticosteroids are extracted from plasma into ether, and the extract is purified either by passing through a magnesium silicate column or by solvent partitioning. Interference from endogenous hydrocortisone is removed by selective derivatization with Girard Reagent T. Following derivatization, prednisolone can be quantitatively separated from the water-soluble hydrocortisone derivative by simple solvent partitioning. The extracted prednisone and prednisolone are converted to their corresponding methoxyimino trimethylsilyl derivatives, and subjected to GLC-mass spectrometry. Prednisone and prednisolone plasma profiles following a 15-mg oral dose of prednisone in a human volunteer are presented. The method can measure prednisone and prednisolone in plasma at the nanogram per milliliter level.
Chromatography, Gas↗
Subdivisions of the HLA-B5 and Bw35 complex.
Population studies in 579 individuals, previously phenotyped to be B5 or Bw35, were carried out with 23 HLA antisera defining the B5-Bw35 complex. The inheritance of five subdivisions in this complex, B5.1, B5.2, B5.y, Bw35 and BHR were tested in 23 families. Differing frequencies of these specificities were observed in American Indians, Blacks, Caucasians, Chinese, Filipinos, Japanese and Mexican Americans.
Epitopes↗
Bile salts of the lungfishes Lepidosiren, Neoceratodus and Protopterus and those of the coelacanth Latimeria chalumnae Smith.
1. Bile salts of the coelacanth Latimeria chalumnae Smith (five specimens) and of the three living genera of lungfish (Dipnoi) were examined as completely as possible and compared. 2. The small 'bile acid' fractions include no more than traces of well-known C27 or C24 acids (free or conjugated) and the functioning bile salts must be regarded as alcohol sulphates. 3. Comparison of the alcohols suggest that (a) Latimeria stands biochemically outside the animal group which includes the Dipnoi, (b) Protopterus and Lepidosiren are more closely related to one another than either is to Neoceratodus, (c) all four primitive osteiychtheans have some amphibian affinities, (d) there are affinities between Latimeria and Dipnoi and ostariophysan families (especially Cyprinidae and Catostomidae) and (e) there are biochemical links between Dipnoi and lampreys.
Amphibians↗
A more detailed study of bile salt evolution, including techniques for small-scale identification and their application to amphibian biles.
1. Methods have been developed for the isolation and identification of small amounts of bile salts and of bile acids and alcohols obtained by solvolysis. These methods involve preparative and analytical t.l.c., purification on columns of protonated Al(2)O(3) and Sephadex LH-20 and also g.l.c.-mass spectroscopy of solvolysis products. 2. Application to 29 species of frogs and toads has confirmed the constancy of bile salt patterns in a single species, including colour phases in two instances, and has revealed great variations between different species in some genera (e.g. Rana, Ptychadena) and little difference between widely distributed species in others (e.g. Bufo). 3. Taxonomic deductions should be made with caution and with regard to the physiological significance of the biochemical character considered. The molecular differences found might be interpreted as indicating variations in the rate of evolution.
Amphibians↗
Induction of cell-mediated immunity against leukemia EL4 in C57BL mice.
Explore the source record for details and available documents.
Animals↗
Rejection of ascites tumor allografts. II. A pathway for cell-mediated tumor destruction in vitro by peritoneal exudate lymphoid cells.
A pathway for cell-mediated tumor destruction in vitro by immune peritoneal exudate lymphoid cells has been proposed. The union of lymphocytes and tumor cells precedes the formation of an intermediate phase leading to lysis. The initial interaction is only partially temperature dependent. The cytolytic process per se is highly temperature dependent, being negligible at 25 degrees C but proceeding rapidly at 37 degrees C. (51)Cr release from tumor cells is demonstrable within 10 min at 37 degrees C and can be reversibly arrested by cooling. Once initiated, lysis is largely independent of additional interactions and continues at almost full rate for 30 min. The effector cells are not lysed and appear to be free to enter into further effector cycles.
Animals↗