Publications by authors named "Sheng D"

Background: Chronic obstructive airway diseases (COAD), characterized by mucus hypersecretion, lead to exercise intolerance. Incentive spirometry has been used to prevent postoperative pulmonary atelectasis.

Methods: To compare the efficacy of two incentive spirometers, Coach (volume-oriented) and Triflo (flow-oriented), in the work of breathing in COAD patients, 22 patients were randomized in this study: 12 patients (Triflo-II group) initially used Triflo-II for 10 minutes and then Coach for the same period.

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The mechanism of lignin peroxidase (LiP) was examined using bovine pancreatic ribonuclease A (RNase) as a polymeric lignin model substrate. SDS/PAGE analysis demonstrates that an RNase dimer is the major product of the LiP-catalyzed oxidation of this protein. Fluorescence spectroscopy and amino acid analyses indicate that RNase dimer formation is due to the LiP-catalyzed oxidation of Tyr residues to Tyr radicals, followed by intermolecular radical coupling.

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2-Chloro-1,4-dimethoxybenzene (2Cl-1,4-DMB) oxidation by lignin peroxidase (LiP) proceeds via the formation of the 2Cl-1,4-DMB cation radical as indicated by ESR and UV/vis spectroscopy. The products of the LiP-catalyzed oxidation of 2Cl-1,4-DMB were identified as 2-chloro-1,4-benzoquinone and the dimers dichlorotetramethoxybiphenyl and chloro(chlorodimethoxyphenyl)benzoquinone. The addition of anisyl alcohol (AA) rapidly quenched the 2Cl-1,4-DMB cation radical optical absorption bands, suggesting that the cation radical directly mediates the oxidation of AA.

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Lignin peroxidase (LiP), from Phanerochaete chrysosporium, in the presence of H2O2 and tetranitromethane (TNM), oxidizes veratryl (3,4-dimethoxybenzyl) alcohol (VA) (I) to veratraldehyde (IV), 4,5-dimethoxy-2-nitrobenzyl alcohol (V), and 3,4-dimethoxy-nitrobenzene (VI). The formation of these products is explained by a mechanism involving the one-electron oxidation of VA by LiP to produce the corresponding cation radical, which loses a proton to generate the benzylic radical. The latter reduces TNM to generate the trinitromethane anion (VIII) and the nitrogen dioxide radical (.

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Lignin peroxidase (LiP) from Phanerochaete chrysosporium catalyzes irreversible oxidative damage to ferricytochrome c (Cc3+) in the presence of H2O2 and 3,4-dimethoxybenzyl (veratryl) alcohol (VA). Atomic absorption analysis and UV/vis spectroscopy indicate that the oxidation of Cc3+ is accompanied by a loss of heme iron from the protein and probably oxidation of the porphyrin ring. At H2O2 concentrations of 7.

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Manganese peroxidase (MnP) from Phanerochaete chrysosporium exhibits haloperoxidase activity at low pH. In the presence of hydrogen peroxide, MnP oxidizes bromide and iodide as measured by the formation of tribromide and triiodide complexes and the halogenation of various organic substrates. The optimum pHs for bromide and iodide oxidation are 2.

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Two manganese peroxidase isozymes, MnP1 and MnP2, were purified from the extracellular medium of ligninolytic cultures of Dichomitus squalens. The proteins were purified to homogeneity using DEAE-Sepharose chromatography and Mono Q fast protein liquid chromatography. MnP1 and MnP2 have molecular masses of 48000 and 48900 Da, respectively, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

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Recurrent hemorrhage has been reported in humans as a result of acquired antibody inhibitors which interfere with the crosslinking of fibrin by factor XIII. One type of these inhibitors (Type III) prevents activated factor XIII from acting on fibrin. We have generated an antifibrin monoclonal antibody, called mAb 4A5, which binds to a peptide sequence at the carboxyl-terminus of human fibrinogen gamma-chains.

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Efforts to develop an improved assay for plasma and tissue transglutaminase have led us to a convenient, sensitive microtiter plate assay for coagulation factor XIII using human fibrinogen as an immobilized substrate. Factor XIII was activated in the presence of calcium, thrombin, and immobilized fibrinogen and then assayed by adding biotinylcadaverine. The reaction was terminated by adding EDTA and the level of incorporated biotin was measured with streptavidin-beta-galactosidase.

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We demonstrate direct oxidation of ferrocytochrome c by lignin peroxidase (LiP) from the lignin-degrading basidiomycete, Phanerochaete chrysosporium. Steady-state kinetic data fit a peroxidase ping-pong mechanism rather than an ordered bi-bi ping-pong mechanism, suggesting that the reductions of LiP compounds I and II by ferrocytochrome c are irreversible. The pH dependence of the overall reaction apparently is controlled by two factors, the pH dependence of the electron-transfer rate and the pH dependence of enzyme inactivation in the presence of H2O2.

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By deriving an anti-peptide monoclonal antibody, mAb 7A4, we characterized the relatively unstudied carboxyl-terminal end of the a-chain of human factor XIII, the plasma transglutaminase. MAb 7A4 was directed against the last eight amino acids (Gln-Ile-Gln-Arg-Arg-Pro-Ser-Met) and bound with a dissociation constant of 3.4 x 10(-8)M.

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Plasma levels of the renin-angiotensin-aldosterone system (RAAS) and atrial natriuretic peptide (ANP) were studied in healthy male pilots, and in a ground crew control group. Plasma concentrations of angiotensin I (A I), angiotensin II (A II) and aldosterone (Aldo) were measured in the pilots before and after flight by radioimmunoassay. Results showed that the plasma concentrations of A I, A II, and Aldo were much higher after flight than before flight, and were different from samples taken from the control group (p less than 0.

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