601
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Pohlmann R, Hasilik A, Cheng S, Pemble S, Winchester B, von Figura K. Synthesis of lysosomal alpha-mannosidase in normal and mannosidosis fibroblasts. Biochem Biophys Res Commun 1983; 115:1083-9. [PMID: 6626219 DOI: 10.1016/s0006-291x(83)80046-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The biosynthesis and secretion of lysosomal alpha-mannosidase was studied in metabolically labelled fibroblasts from controls and two patients with mannosidosis. Normal fibroblasts secrete alpha-mannosidase as a 110kDa polypeptide. Intracellularly alpha-mannosidase is represented by several polypeptides with apparent Mrs ranging from 40 to 67kDa. In two mannosidosis cell lines none of intra- and extracellular polypeptides of alpha-mannosidase were detectable. The mannosidosis fibroblasts secreted acid alpha-mannosidase activity at one third of the normal rate. In contrast to normal cells the secretion was not enhanced by NH4C1 and the secreted activity was not immunoprecipitable, indicating that the acid alpha-mannosidase activity secreted by mannosidosis fibroblasts is not related to the lysosomal alpha-mannosidase.
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602
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Friedman SJ, Cheng S, Skehan P. The occurrence of polysialogangliosides in a human trophoblast cell line. FEBS Lett 1983; 152:175-9. [PMID: 6681780 DOI: 10.1016/0014-5793(83)80373-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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603
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Cheng S, Merlino GT, Pastan IH. A versatile method for the coupling of protein to DNA: synthesis of alpha 2-macroglobulin-DNA conjugates. Nucleic Acids Res 1983; 11:659-69. [PMID: 6188106 PMCID: PMC325744 DOI: 10.1093/nar/11.3.659] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We describe a simple, general method to link proteins covalently to DNA. The method uses two reagents, N-acetyl-N'-(p-glyoxylylbenzoyl)cystamine and 2-iminothiolane. The former reacts specifically with nonpaired quanine residues and upon reduction generates a free sulfhydryl group. The latter reacts with a protein to provide another sulfhydryl group which is subsequently conjugated to DNA by an intermolecular disulfide interchange reaction. Using this method alpha 2-macroglobulin was conjugated to plasmid DNA encoding the Herpes simplex virus-1 thymidine kinase gene or a DNA fragment containing the E. coli chloramphenicol acetyltransferase gene. Up to 20% of the total DNA was conjugated to alpha 2-macroglobulin and the alpha 2-macroglobulin-DNA conjugate had a protein/DNA molar ratio of approximately two. The whole reaction takes place under very mild conditions in aqueous solution. The structure of DNA appears not to be significantly affected by the chemical modification. This method may prove useful in ligand directed gene transfer studies.
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604
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Hanover JA, Cheng S, Willingham MC, Pastan IH. alpha 2-Macroglobulin binding to cultured fibroblasts. Solubilization and partial purification of binding sites. J Biol Chem 1983; 258:370-7. [PMID: 6184373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Binding sites having the characteristics of receptors for "activated" alpha 2-macroglobulin (alpha 2M) have been solubilized with octyl-beta-D-glucoside from fibroblast membranes. When the detergent was removed by dialysis, the resulting insoluble extract was shown to bind 125I-alpha 2M specifically. Analysis of the binding data using a nonlinear curve-fitting program suggests that the solubilized preparation contains two classes of binding sites (KD = 0.34 nM and KD = 104 nM). Membranes or solubilized extracts from KB cells which lack alpha 2M binding sites did not specifically bind 125I-alpha 2M. The solubilized binding sites from fibroblasts were inactivated by boiling and trypsin treatment, and required Ca+2 for maximal binding. In addition, the high affinity binding of 125I-alpha 2M to the solubilized receptor was inhibited by bacitracin and by alpha-bromo-5-iodo-4-hydroxy-3-nitroacetophenone, two agents which interfere with the uptake of alpha 2M in cultured fibroblasts. Using a combination of ion exchange and gel permeation chromatography, we have purified the high affinity alpha 2M binding site approximately 100-fold from membrane derived from NIH-3T3 (spontaneously transformed) fibroblasts grown as tumors in mice. The receptor is apparently an acidic protein and the receptor octyl-beta-D-glucoside complex has a Stokes radius of 45-50 A as measured by gel filtration.
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605
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Hanover JA, Cheng S, Willingham MC, Pastan IH. alpha 2-Macroglobulin binding to cultured fibroblasts. Solubilization and partial purification of binding sites. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)33267-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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606
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North WG, Valtin H, Cheng S, Hardy GR. The neurophysins: production and turnover. PROGRESS IN BRAIN RESEARCH 1983; 60:217-25. [PMID: 6665139 DOI: 10.1016/s0079-6123(08)64389-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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607
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Horiuchi R, Johnson ML, Willingham MC, Pastan I, Cheng S. Affinity labeling of the plasma membrane 3,3',5-triiodo-L-thyronine receptor in GH3 cells. Proc Natl Acad Sci U S A 1982; 79:5527-31. [PMID: 6291049 PMCID: PMC346937 DOI: 10.1073/pnas.79.18.5527] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The binding of 3,3',5-triiodo-L-thyronine (T3) to GH3 rat pituitary tumor cells was studied at 15 degrees C and was shown to be saturable, reversible, and stereospecific. Least-squares analysis of the binding data showed two classes of binding sites with dissociation constants of 1.8 +/- 0.2 nM and 260 +/- 30 nM and binding capacities of (5.2 +/- 0.2) X 10(4) and (1.6 +/- 0.2) X 10(6) sites per cell, respectively. Affinity labeling of intact cells was carried out by incubation of cells with 0.3 nM N-bromoacetyl-[125I]T3 at 15 degrees C for 1 hr. Analysis of the cellular extracts by sodium dodecyl sulfate gel electrophoresis showed three labeled protein bands with apparent molecular masses of 55, 47, and 33 kilodaltons (kDal) in a ratio of 86:7:7. The labeling of only the 55-kDal protein band was selectively reduced to 50% by 20 microM unlabeled T3. Highly purified plasma membranes of GH3 cells were prepared and shown to be free of nuclei. Affinity labeling of the purified plasma membranes gave the same labeling pattern as with intact cells. Peptide mapping by Staphylococcus aureus V8 digestion of the 55-kDal protein from cells or plasma membranes gave the identical peptide fragments. Thus the 55-kDal protein labeled from intact cells is the same protein as that from purified plasma membranes. These results together with our earlier findings [Horiuchi, R., Cheng, S.-y., Willingham, M. & Pastan, I. (1982) J. Biol. Chem. 257, 3139-3144] suggest that the 55-kDal protein may be involved in mediating the uptake of T3 in GH3 cells.
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608
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Johnson SM, Chan C, Cheng S, Shimek JL, Nygard G, Khalil SK. Isocratic high-performance liquid chromatographic method for the determination of tricyclic antidepressants and metabolites in plasma. J Pharm Sci 1982; 71:1027-30. [PMID: 7131268 DOI: 10.1002/jps.2600710918] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An isocratic high-performance liquid chromatographic method for the determination of six tricyclic antidepressants and their major metabolites is presented. Hexane containing 0.5% diethylamine was used as an extraction solvent to minimize adsorption onto glass. A reversed-phase cyanopropylsilane column was used with a mobile phase consisting of 70% acetonitrile and 30% 0.03 M acetate buffer, pH 7.0. Good identification and quantitation were obtained by the use of both UV detection at 245 nm and spectrofluorometric detection with an excitation wavelength of 276 nm and an emission filter with a 370-nm cutoff. A minimum detectable limit of less than 5 ng/ml of plasma is possible with this system. The reproducibility and precision of the method are shown from the analysis of samples containing 20-400 ng/ml in plasma.
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609
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Marlin GE, Thompson PJ, Reddel HK, Chow CM, Cheng S. Bronchodilator activity of prazosin in patients with allergic rhinitis and asthma. Br J Clin Pharmacol 1982; 13:445-8. [PMID: 7059447 PMCID: PMC1402106 DOI: 10.1111/j.1365-2125.1982.tb01400.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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610
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Hunt PS, Davidson AJ, Alden J, Cheng S. Bile and serum levels of tinidazole after a single oral dose. Br J Clin Pharmacol 1982; 13:233-4. [PMID: 7059421 PMCID: PMC1402006 DOI: 10.1111/j.1365-2125.1982.tb01363.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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611
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Cheng S. [Electron-microscopic observations on platelet aggregation groups (author's transl)]. ZHONGHUA YI XUE ZA ZHI 1981; 61:523-6. [PMID: 6804059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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612
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Marlin GE, Cheng S, Thompson PJ. Sputum and plasma doxycycline concentrations after a single oral 600 mg doxycycline dose in patients with chronic bronchitis. EUROPEAN JOURNAL OF RESPIRATORY DISEASES 1981; 62:276-80. [PMID: 7308339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Plasma and sputum concentrations of doxycycline were measured in 10 patients with chronic bronchitis for a period of 96 h after a single oral 600 mg dose of doxycycline. The plasma doxycycline levels exceeded the minimal inhibitory concentrations (MIC) against common respiratory pathogens. Sputum doxycycline levels were detected in nine patients and these compared favourably with the above MICs for 24 h. The mean percent ratio of sputum/plasma doxycycline level reached a maximum of 28% at 48 h. There was a positive correlation between sputum and plasma doxycycline levels. This study provides pharmacokinetic support for a single oral 600 mg dose of doxycycline in the treatment of acute bronchial infection.
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613
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Goldknopf IL, Cheng S, Andersen MW, Busch H. Loss of endogenous nuclear protein A24 lyase activity during chicken erythropoiesis. Biochem Biophys Res Commun 1981; 100:1464-70. [PMID: 6271123 DOI: 10.1016/0006-291x(81)90683-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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614
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Cocks PS, Munro R, Norton B, Nutting J, Shanker S, Cheng S. Prospective comparative trial of tinidazole and metronidazole as prophylaxis for elective hysterectomy. Aust N Z J Obstet Gynaecol 1981; 21:116-20. [PMID: 6945849 DOI: 10.1111/j.1479-828x.1981.tb00795.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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615
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Nassar K, Cheng S, Levy D. The effect of diabetes on hepatocyte plasma membrane fluidity and concanavalin A-induced agglutination. Exp Cell Res 1981; 132:99-104. [PMID: 7202567 DOI: 10.1016/0014-4827(81)90087-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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616
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617
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Levy D, Cheng S. Photoaffinity labeling of anion transport components in hepatocyte plasma membranes. Ann N Y Acad Sci 1980; 346:232-43. [PMID: 6930184 DOI: 10.1111/j.1749-6632.1980.tb22102.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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618
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Cheng S, Levy D. Characterization of the anion transport system in hepatocyte plasma membranes. J Biol Chem 1980; 255:2637-40. [PMID: 7358691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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619
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Cheng S, Levy D. Characterization of the anion transport system in hepatocyte plasma membranes. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85779-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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620
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Cheng S, Morrone S, Robbins J. Effect of deglycosylation on the binding and immunoreactivity of human thyroxine-binding globulin. J Biol Chem 1979; 254:8830-5. [PMID: 113401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thyroxine-binding globulin (TBG), prepared from human serum by an improved purification method, was treated with a mixture of neuraminidase, beta-galactosidase, alpha-mannosidase, and beta-N-aectylglucosaminidase, which resulted in the removal of approximately 86% of saccharides. Purification by thyroxine-Sepharose affinity chromatography gave a homogeneous protein as shown by equilibrium sedimentation and sodium dodecylsulfate-polyacrylamide gel electrophoresis. Amino acid and NH2-terminal sequence analysis indicated that the protein moiety was intact. Deglycosylation had no effect on the stoichiometry of the binding of L-thyroxine as shown by tryptophanyl fluorescence quenching and equilibrium dialysis at pH 8.6 and 25 degrees C. However, the affinity constant for L-thyroxine was reduced from 1.6 X 10(9) M-1 to 0.58 X 10(9) M-1. Analysis of radioimmunoassay data revealed that deglycosylation resulted in a slight decrease of the affinity constant for anti-TBG antibody from 3.9 X 10(10) M-1 to 1.8 X 10(10) M-1. These results suggest that the polypeptide moiety, rather than the heterosaccharides, contains the antigenic determinants. Removal of the majority of the heterosaccharides of TBG has only a minor effect on its immunoreactivity and on the binding of thyroid hormone.
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621
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Cheng S, Levy D. The effects of cell proliferation on the lipid composition and fluidity of hepatocyte plasma membranes. Arch Biochem Biophys 1979; 196:424-9. [PMID: 485159 DOI: 10.1016/0003-9861(79)90293-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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622
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Cheng S, Morrone S, Robbins J. Effect of deglycosylation on the binding and immunoreactivity of human thyroxine-binding globulin. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86774-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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623
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Marlin GE, Cheng S. Pharmacokinetics and tolerability of a single oral 600-mg dose of doxycycline. Med J Aust 1979; 1:575-6. [PMID: 38382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pharmacokinetics of a single orally administered 600-mg dose of doxycycline (six 100-mg film-coated tablets) was studied in 18 healthy subjects. Plasma doxycycline levels remained above 1.35 mumol/L for 48 hours and compared favourably with the mean inhibitory concentrations of doxycycline against the common infecting organisms in chronic bronchitis. In a separate tolerability study in 37 healthy subjects, there was no significant difference between doxycycline and placebo in the incidence of adverse effects.
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624
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625
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Cheng S, Eberhardt NL, Robbins J, Baxter JD, Pastan I. Fluorescent rhodamine-labeled thyroid hormone derivatives: synthesis and binding to the thyroid hormone nuclear receptor. FEBS Lett 1979; 100:113-6. [PMID: 437091 DOI: 10.1016/0014-5793(79)81143-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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