Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A flow cytometric assay has been developed to detect and quantitate human immunodeficiency virus (HIV)-infected peripheral blood mononuclear cells obtained from HIV-seropositive patients. Peripheral blood was obtained from patients attending an acquired immune deficiency syndrome clinic, and mononuclear cells were separated by centrifugation onto Ficoll-Hypaque. The cell layer at the interface was removed, washed in phosphate-buffered saline without Ca2+ and Mg2+, and fixed with 90% methanol, and intracellular HIV antigens were detected by indirect immunofluorescence with monoclonal antibodies to HIV antigens as the primary antibody and fluorescein isothiocyanate-conjugated goat anti-mouse immunoglobulin G F(ab')2 antibody as the secondary antibody. DNA content was determined by propidium diiodide staining after RNase treatment. These fluorochrome-treated cells were analyzed for two-color fluorescence by flow cytometry. The results showed that HIV-infected cells in peripheral blood that have been treated with monoclonal antibodies to the p24 or nef antigens of HIV can be detected and quantitated by flow cytometry. The percentage of p24 antigen-positive mononuclear cells had a significant correlation (P = 0.0001) with the clinical status of the patient, i.e., those with a high percentage of p24 antigen-positive cells had a poorer prognosis than those with a lower percentage of p24 antigen-positive mononuclear cells. In addition, for those in Centers for Disease Control groups III and IV, there was an inverse correlation between the percentage of p24 antigen-positive mononuclear cells and the number of T4 cells. However, cell-associated antigen detection by flow cytometry did not correlate with detection of antigen in sera of HIV-seropositive patients by the standard antigen capture enzyme-linked immunosorbent assay. This lack of correlation was probably due to the presence of immune complexes in the sera of HIV-seropositive patients. These results suggest that flow cytometry can be used as a rapid, sensitive, and quantitative assay system for the determination of the antigen status of HIV-seropositive patients and that it may be more useful as an indicator of disease progression than the currently used antigen detection methods.
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PMID:Detection and quantitation of human immunodeficiency virus-infected peripheral blood mononuclear cells by flow cytometry. 197 May 76

Cells of intraperitoneally transplanted murine leukaemias and sarcomas (L-1210, EL-4, MC-11 and SA-1), were found to be toxic for target cells usually employed for assaying NK cells (K-562, EL-4, YAC-1). The 3H-uridine-ribonuclease method used in our study, in contrast to the 51Cr assay, revealed not only cytotoxicity but also reversible damage to target cell membrane (membrane toxicity). This damage became irreversible if target cells had been pretreated with actinomycin D. To exclude the possible role of an admixture of NK, macrophages and T killer cells, contaminants were removed from suspensions of peritoneal tumour cells from syngeneic mice by adherence to plastic surfaces and separation on Hypaque-Ficoll, and from tumour cells grown in vivo or in vitro and then maintained in allogeneic animals by additional treatment with anti-H-2 sera and complement. The toxic effect depended directly on the dosage of tumour cells. Unlabelled target cells inhibited tumour cell toxicity. The medium used for incubating tumour cells was not toxic for target cells.
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PMID:Tumour cell toxicity for the targets of natural killer cells. 664 10

Glucocorticoid-specific binding macromolecules were measured and characterized in L2C cells, a B-lymphocyte guinea pig leukemia that is resistant to administered cortisol or adrenocorticotrophic hormone. L2C cells were harvested by cardiac puncture followed by Ficoll:Hypaque separation techniques. The cells were lysed by sonication, and the cytosol was obtained after centrifugation at 106,000 x g for 60 min at 0 degrees. Cytosol glucocorticoid receptor measurements were obtained by hydroxylapatite assay or column chromatography using Sephadex G-25. Maximal specifically bound [3H]triamcinolone acetonide in the cytosol fraction was 300 fmol/10(8) cells. Scatchard plot of specific L2C cytosol binding gave a Kd of 18 nM and an estimate of 2000 binding sites/cell. The specificity of binding in L2C cytosol was triamcinolone acetonide > dexamethasone > cortisol > progesterone > testosterone = estradiol. Binding of [3H]triamcinolone acetonide to cytosol glucocorticoid receptors was maximal at 22 hr of incubation at 19 degrees, and the receptor complex was stable for 48 hr. The receptor complex was not affected by DNase or RNase, but the receptor complex was lost with pronase or heat denaturation. Whole-cell binding assays were also performed, which resulted in similar quantities of maximally bound glucocorticoid receptor as well as the specificity of binding of various hormone analogs as found in the cytosol receptor assays. Transferring the whole cells from 0 to 22 degrees resulted in the appearance in nuclei of approximately 65% bound receptors. However, these translocated receptor complexes do not appear to affect the viability of the L2C cells as measured by trypan blue exclusion.
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PMID:Characterization of glucocorticoid-specific binding in the L2C leukemia. 693 47