151
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Chen ZM, Pettitt BM, Reiter G, Moss SC, Karim OA. Comparison of structural theories for graphite intercalation compounds. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:10476-10478. [PMID: 10002897 DOI: 10.1103/physrevb.46.10476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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152
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153
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Chen ZM, Pettitt BM. Diatomic intercalation in lamellar graphite compounds. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:8173-8178. [PMID: 9994988 DOI: 10.1103/physrevb.42.8173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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154
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Del Maschio A, Bazzoni G, Zatta A, Chen ZM, Dejana E, Prosdocimi M. Cloricromene inhibits the activation of human platelets by ADP alone or in combination with adrenaline. Eur J Pharmacol 1990; 187:541-5. [PMID: 2073928 DOI: 10.1016/0014-2999(90)90384-i] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cloricromene may inhibit platelet activation induced by several agonists. In this study we report that ADP and adrenaline synergistically promote platelet aggregation and cytoplasmic Ca2+ movements in aequorin-loaded platelets. Cloricromene caused dose-dependent reduction in platelet aggregation and cytoplasmic Ca2+ movements after exposure of the cells to a low concentration of ADP (2 microM) or to a combination of ADP (2 microM) and adrenaline (10 microM). Cloricromene's inhibitory action may be of considerable pharmacological interest since platelet activation by a combination of agonists may mimic the conditions under which thrombosis occurs in vivo.
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Del Maschio A, Evangelista V, Rajtar G, Chen ZM, Cerletti C, De Gaetano G. Platelet activation by polymorphonuclear leukocytes exposed to chemotactic agents. THE AMERICAN JOURNAL OF PHYSIOLOGY 1990; 258:H870-9. [PMID: 2156456 DOI: 10.1152/ajpheart.1990.258.3.h870] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human platelets were loaded with aequorin, a Ca2(+)-sensitive photoprotein, and tested in the platelet-ionized calcium aggregometer for simultaneous recording of platelet aggregation and intraplatelet Ca2+ levels both in the presence and in the absence of autologous polymorphonuclear leukocytes. Cells were exposed to one of three chemotactic stimuli: platelet-activating factor (PAF), N-formyl-methionyl-leucyl-phenylalanine (FMLP), or leukotriene B4 (LTB4). Platelets alone aggregated and showed intracellular Ca2+ movement only when exposed to PAF. Amplification of both platelet aggregation and intraplatelet Ca2+ movement was induced by PAF in the presence of leukocytes. Aggregation and intraplatelet Ca2+ mobilization were also observed in the presence of leukocytes activated by either FMLP or LTB4. Both parameters increased with the concentration of the stimuli and/or the number of leukocytes. Platelet thromboxane B2 production was also significantly increased in the presence of leukocytes. Addition of platelets at different times after leukocyte activation resulted in progressively reduced cytoplasmic Ca2+ increase. Cell-free supernatants prepared from FMLP-stimulated leukocytes were able to induce platelet aggregation, thromboxane B2 generation, and Ca2+ mobilization, although at a reduced degree as compared with intact leukocyte addition. The activity of leukocyte supernatants was stable at 37 degrees C for up to 30 min and was suppressed by trypsin inhibitor. Our study indicates that stimulated leukocytes release a soluble enzymatic activity able to activate platelets; cell-to-cell interaction may also play a role in this phenomenon. Platelet-leukocyte interaction could have physiopathological relevance and constitutes a new model for studying old and new platelet inhibitory drugs.
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Herrera-Estrella A, Chen ZM, Van Montagu M, Wang K. VirD proteins of Agrobacterium tumefaciens are required for the formation of a covalent DNA-protein complex at the 5′ terminus of T-strand molecules. EMBO J 1988; 7:4055-62. [PMID: 3243272 PMCID: PMC455113 DOI: 10.1002/j.1460-2075.1988.tb03299.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The T-DNA transfer process of Agrobacterium tumefaciens is activated by the induction of the Ti plasmid virulence (vir) loci by plant signal molecules such as acetosyringone. Upon initiation of the T-DNA transfer process, site-specific nicks occur at the 25-bp border sequences. This cleavage leads to the generation of a free, linear ssT-DNA molecule which is bound by sequence non-specific VirE proteins. Here we present evidence for the involvement of other acetosyringone-induced proteins in the formation of a covalent complex between the T-strand and protein, designated the T-complex. Alkaline gel-electrophoretic analysis showed that proteins specifically bind to the 5' termini of nicked T-DNA molecules. The T-complex can be formed in Escherichia coli when the VirD1 and VirD2 proteins are expressed.
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157
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Tornow W, Howell CR, Roberts ML, Felsher PD, Chen ZM, Walter RL, Mertens G, Slaus I. Low-energy neutron-proton analyzing power and the new Bonn potential and Paris potential predictions. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1988; 37:2326-2331. [PMID: 9954713 DOI: 10.1103/physrevc.37.2326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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158
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Gambino MC, Passaghe S, Chen ZM, Bucchi F, Gori G, Latini R, de Gaetano G, Cerletti C. Selectivity of oral aspirin as an inhibitor of platelet vs. vascular cyclooxygenase activity is reduced by portacaval shunt in rats. J Pharmacol Exp Ther 1988; 245:287-90. [PMID: 3129553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Oral aspirin can be extensively hydrolyzed to salicylate in the stomach and liver before it enters the systemic circulation. "Presystemic" acetylation of platelets may thus occur during aspirin absorption. This may result in concomitant sparing of peripheral vascular cyclooxygenase mainly exposed to salicylate. We tested whether the "biochemical selectivity" of p.o. aspirin as an inhibitor of platelet rather than vascular cyclooxygenase was reduced by elimination of the "first-pass" hepatic metabolism. A portacaval shunt was inserted in anesthetized rats by connecting the portal vein to the inferior vena cava through a heparinized polyethylene "Y" cannula. Sham-operated rats acted as controls. Ninety minutes after recovery from anesthesia rats were given aspirin p.o. (10 mg/kg) and 45 min later serum thromboxane B2 and 6-keto-prostaglandin F1 alpha formation by vascular rings was evaluated by radioimmunoassay. Serum thromboxane B2 was almost suppressed completely in all animals; vascular 6-ketoprostaglandin F1 alpha was reduced significantly (by 40-60% in aorta and vena cava) in rats with the portacaval shunt but not in sham-operated animals. The results in rats with the shunt were similar to those obtained previously after i.v. aspirin. Fifteen minutes after aspirin, plasma levels of unmetabolized drug measured by high-pressure liquid chromatography were significantly higher in rats with portacaval shunt (0.56 +/- 0.16 micrograms/ml; n = 5) than in sham-operated controls (0.16 +/- 0.02 micrograms/ml; n = 5). These findings support directly the role of first-pass hepatic metabolism in the "biochemical selectivity" of p.o. aspirin.
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Latini R, Sica A, Marchi S, Chen ZM, Gavinelli M, Benfenati E. High-performance liquid chromatographic separation and mass spectrometric identification of propafenone, 5-hydroxypropafenone and N-depropylpropafenone. JOURNAL OF CHROMATOGRAPHY 1988; 424:211-4. [PMID: 3366834 DOI: 10.1016/s0378-4347(00)81097-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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160
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Chen ZM, Cerletti C, de Gaetano G, Bertelé V. Response of human platelets exposed to arachidonate upon stimulation with other agonists: possible role of Ca2+i movement. Biochem Biophys Res Commun 1987; 149:1193-9. [PMID: 3122746 DOI: 10.1016/0006-291x(87)90534-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Arachidonate (25 microM) induced only 20% maximal platelet aggregation but 80% maximal cytoplasmic ionized calcium movement (as measured by the photoprotein aequorin). Preincubation with 25 microM arachidonate prevented platelet aggregation and cytoplasmic ionized calcium movement induced by threshold concentrations of the thromboxane A2 analogue U-46619, but did not prevent platelet aggregation induced by threshold concentrations of thrombin, despite a marked reduction of cytoplasmic ionized calcium movement. These findings suggest that thrombin may employ pools of cytoplasmic ionized calcium and/or mechanisms to mobilize it different from those utilized by arachidonate and its metabolites.
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161
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Chen ZM, Colombo T, Conforti L, Grazia Donelli M, Fiedorowicz RJ, Marchi S, Paolini A, Riva E, Zuanetti G, Latini R. Effects of three new anthracyclines and doxorubicin on the rat isolated heart. J Pharm Pharmacol 1987; 39:947-50. [PMID: 2892924 DOI: 10.1111/j.2042-7158.1987.tb03137.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The acute cardiac toxicity of three second-generation anthracycline analogues and doxorubicin was compared in a model of the rat isolated Langendorff perfused heart. The drugs, doxorubicin (DX), 4-epi-doxorubicin (4'EDX), 4-demethoxy-daunorubicin (4DMDR) and 4'-deoxy-doxorubicin (4'dxDX) were infused for 40 min at a concentration of 26 microM into the isolated hearts. All four compounds significantly reduced cardiac work and its first derivative. The time to 50% decrease in work (TW50) was respectively 36, 23, 9 and 7 min for DX, 4'EDX, 4'dxDX and 4DMDR. The three anthracycline derivatives, but not DX, significantly increased coronary resistance. Heart rate was reduced by all compounds compared with baseline, but not compared with controls. Rhythm disturbances were seen with all five hearts perfused with 4DMDR, which stopped beating before 40 min; 2/5 hearts in the 4'EDX group and 1/5 hearts in the 4'dxDX group also stopped before the end of perfusion. All the compounds reached concentrations in the myocardium 8 to 50 times higher than in the perfusing medium. The more cardiotoxic the compound, the higher was its myocardial concentration; a significant correlation was found for all four agents. Noradrenaline was never measurable in the perfusate of control and DX hearts; perfusion with the three anthracycline derivatives caused some release, but the pattern was not clearcut and the maximum concentrations attained in the perfusate were relatively low (less than or equal to 1.6 X 10(-9) M). In conclusion, in the rat isolated perfused heart, the early cardiotoxicity induced by equimolar concentrations of the three anthracycline compounds was greater than that induced by DX and was directly related to drug accumulation in the myocardium. Catecholamines do not seem to have a major role in the development of toxicity in this model.
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162
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Chen ZM, Yang ZD, Zhu YG. [Treatment of retrohepatic vena cava obstruction by prehepatic cavoatrial shunt]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1987; 25:425-7, 446. [PMID: 3677950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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163
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Wells JC, Johnson NR, Baktash C, Lee IY, McGowan FK, Rao MN, Riedinger LL, Janzen V, Ma WC, Wen S, Chen ZM, Semmes PB, Leander GA, Chen YS. Low-frequency anomaly in 172Os moment of inertia. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1987; 36:431-434. [PMID: 9954090 DOI: 10.1103/physrevc.36.431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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164
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Chen ZM, Li WX. [Blood pressure and mortality rates in some rural communities of Shanghai]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1987; 8:80-3. [PMID: 3621332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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165
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Tornow W, Howell CR, Pfützner HG, Roberts ML, Felsher PD, Chen ZM, Walter RL. Search for a purported resonance in 13C at 20 MeV via analyzing power measurements of 12C(n,n). PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1987; 35:1578-1580. [PMID: 9953937 DOI: 10.1103/physrevc.35.1578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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166
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Chen ZM, Li WX. [Hypocholesterolemia and cancer]. ZHONGHUA YI XUE ZA ZHI 1986; 66:631-3. [PMID: 3098371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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167
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Chen ZM. [The relationship between gastric acid secretory function and differential syndrome treatment--gastric fluid analysis of 70 cases with atrophic gastritis]. ZHONG XI YI JIE HE ZA ZHI = CHINESE JOURNAL OF MODERN DEVELOPMENTS IN TRADITIONAL MEDICINE 1984; 4:224-226. [PMID: 6235968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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168
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Chen ZM. [Homogenic orthotopic transplantation of liver in animal experiment (author's transl)]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1981; 19:280-2. [PMID: 7021095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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