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Yuan C, Acosta D. Dissociation of the cytotoxicity of cocaine from its local anaesthetic effect: A comparison with lidocaine. Toxicol In Vitro 1996; 10:195-204. [DOI: 10.1016/0887-2333(95)00108-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/1995] [Indexed: 10/18/2022]
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252
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Mrenna S, Yuan C. High-pT Higgs boson production at hadron colliders to O( alpha sGF3). PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 53:3547-3554. [PMID: 10020348 DOI: 10.1103/physrevd.53.3547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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253
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Yuan C, Skinner MP, Kaneko E, Mitsumori LM, Hayes CE, Raines EW, Nelson JA, Ross R. Magnetic resonance imaging to study lesions of atherosclerosis in the hyperlipidemic rabbit aorta. Magn Reson Imaging 1996; 14:93-102. [PMID: 8656993 DOI: 10.1016/0730-725x(95)02049-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have developed a high resolution magnetic resonance (MR) imaging technique to serially assess lesions of atherosclerosis in a rabbit model. A volume phased array coil was designed and used to image the abdominal aortas of six atherosclerotic rabbits and two age-, sex-, and weight-matched controls. Lesions of atherosclerosis were induced by a combination of repeat balloon injury and a hyperlipidemic diet. All animals were imaged on at least two occasions 9-16 months after initiation of atherosclerosis. In addition, animals were imaged immediately after sacrifice. Anatomic dissection and histology were performed to verify the MR findings. The volume phased array coil improves the image signal-to-noise ratio over existing extremity coils and resulted in higher resolution images of the abdominal aorta. Proton density-weighted images acquired with 2D/3D fast spin-echo are the most useful sequence to outline the vessel wall and to differentiate wall from lumen and background. Progressive wall thickening and lumen stenosis were observed in the serial images of the diseased rabbits. Wall thickness and lumen area derived noninvasively from the in vivo MR images correlate with postmortem MR images and sections of aorta examined by dissection microscopy and histology. Spin-echo and fast spin-echo imaging with a phased array body coil can be used to accurately assess plaque dimensions, and potentially can be used to image intraplaque features and to monitor lesion progression or regression. It should also be possible to adapt these techniques to assess human disease, especially for peripheral vascular problems.
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Hayes CE, Mathis CM, Yuan C. Surface coil phased arrays for high-resolution imaging of the carotid arteries. J Magn Reson Imaging 1996; 6:109-12. [PMID: 8851414 DOI: 10.1002/jmri.1880060121] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
An MR phased-array coil assembly was developed to obtain high-resolution images of atherosclerotic plaques in the carotid artery. Images of volunteers and patients obtained by using alternative coil designs provided a subjective assessment of the coils' performance, field of view, ease of use, and susceptibility to motion artifacts. A quantitative measurement performed on a phantom indicated that a two-coil phased-array design should produce a 37% better signal-to-noise ratio at the carotids than would a conventional single 3-inch surface coil.
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Kondic L, Gersten JI, Yuan C. Theoretical studies of sonoluminescence radiation: Radiative transfer and parametric dependence. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:4976-4990. [PMID: 9963993 DOI: 10.1103/physreve.52.4976] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
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256
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Bagger J, Barger V, Cheung K, Gunion J, Han T, Ladinsky GA, Rosenfeld R, Yuan C. CERN LHC analysis of the strongly interacting WW system: Gold-plated modes. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 52:3878-3889. [PMID: 10019615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Yuan C, Murakami JW, Hayes CE, Tsuruda JS, Hatsukami TS, Wildy KS, Ferguson MS, Strandness DE. Phased-array magnetic resonance imaging of the carotid artery bifurcation: preliminary results in healthy volunteers and a patient with atherosclerotic disease. J Magn Reson Imaging 1995; 5:561-5. [PMID: 8574042 DOI: 10.1002/jmri.1880050515] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A high resolution MR imaging technique using a custom designed flexible phased-array surface coil was developed to examine the wall of the carotid artery bifurcation in vivo. The phased-array consisted of two overlapping coils which increased the image signal-to-noise ratio at the depth of the carotid artery by approximately 70%, relative to a similarly sized single loop coil. The imaging protocol included a 2D T1-weighted (T1W) spin-echo scan and cardiac gated T2-weighted and proton density-weighted (PDW) fast spin-echo (FSE) scans. Images were obtained of six healthy volunteers and of one patient with known atherosclerotic disease several days before carotid endarterectomy. On T1W and PDW images of the healthy volunteers, the carotid arterial wall appeared to be comprised of two concentric rings; a high signal inner ring and a lower signal outer ring. The MR images of the patient revealed a calcified carotid bifurcation plaque which was confirmed during surgery. The endarterectomy specimen was imaged in vitro with MR and then sectioned histologically for correlation with the patients in vivo images. Our preliminary findings indicate that a high resolution technique may provide a noninvasive technique to study atherosclerosis of the carotid bifurcation.
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Weinberger E, Murakami JW, Shaw DW, White KS, Radvilas MK, Yuan C. Three-dimensional fast spin echo T1-weighted imaging of the pediatric spine. J Comput Assist Tomogr 1995; 19:721-5. [PMID: 7560316 DOI: 10.1097/00004728-199509000-00006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE We evaluated the feasibility of using a three-dimensional (3D) fast SE (FSE) pulse sequence to acquire T1-weighted (T1W) images of the pediatric spine. MATERIALS AND METHODS The 3D FSE T1W images were acquired in nine pediatric patients undergoing spine MRI for different clinical indications. The 3D FSE images were compared with our standard 2D SE T1W images. RESULTS Image contrast was comparable between the two sequences. The 3D FSE sequence produced contiguous thin sections that allowed multiplanar reformations not possible with the 2D SE sequence. CONCLUSION 3D T1W spine imaging with conventional SE-like contrast is feasible with 3D FSE.
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Wiest M, Stump DR, Carlson DO, Yuan C. Studying anomalous WW gamma and WWZ couplings with polarized pp-bar collisions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 52:2724-2736. [PMID: 10019490 DOI: 10.1103/physrevd.52.2724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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261
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Shibata DK, Schmiedl UP, Yuan C, Nelson JA. Two prototype blood-pool agents for contrast-enhanced magnetic resonance angiography of the portal vein in pigs. Acad Radiol 1995; 2:705-8. [PMID: 9419628 DOI: 10.1016/s1076-6332(05)80439-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
RATIONALE AND OBJECTIVES Macromolecular "blood-pool" agents such as polylysine-gadopentetate dimeglumine or albumin-gadopentetate dimeglumine, which provide prolonged intravascular enhancement, were tested as magnetic resonance (MR) angiography contrast agents for the portal vein in pigs. METHODS Phase-contrast MR angiography of the portal veins was performed on six pigs before and after intravenous administration of polylysine-gadopentetate dimeglumine (n = 3) or albumin-gadopentetate dimeglumine (n = 3). RESULTS The contrast-to-noise ratio of the portal veins was improved by 74% and 52%, respectively, using polylysine-gadopentetate dimeglumine or albumin-gadopentetate dimeglumine. More branches of the intrahepatic portal veins were visualized on postcontrast images. CONCLUSION Blood-pool paramagnetic contrast agents improved the visualization of hepatic vasculature using phase-contrast MR angiography in our experimental model.
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Sullivan C, Yuan C. Workplace assaults on minority health and mental health care workers in Los Angeles. Am J Public Health 1995; 85:1011-4. [PMID: 7604900 PMCID: PMC1615521 DOI: 10.2105/ajph.85.7.1011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Workplace violence is becoming increasingly recognized as a serious problem in health care settings. All 628 workers' compensation assaults claimed by minority Los Angeles County health care workers from 1986 through 1990 were abstracted. Population-at-risk data from county personnel computer tapes provided denominators by age, sex, race, job classification, and type of facility. Rates varied by type of facility (rate ratio = 38 for psychiatric hospitals vs public health facilities) and varied by job, with inpatient nursing attendants having the highest rate for caregivers. Most assaults were committed by patients (86%), followed by coworkers (8%). The average cost of an assault ($4879) was relatively low but related to the costlier problem of work-related emotional illness.
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263
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Malkawi E, Yuan C. Effects of a heavy top quark on low energy data using the electroweak chiral Lagrangian. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 52:472-483. [PMID: 10019058 DOI: 10.1103/physrevd.52.472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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264
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He HJ, Kuang YP, Yuan C. Equivalence theorem and probing the electroweak symmetry-breaking sector. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 51:6463-6473. [PMID: 10018409 DOI: 10.1103/physrevd.51.6463] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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265
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Murakami JW, Weinberger E, Tsuruda JS, Mitchell JD, Yuan C. Multislab three-dimensional T2-weighted fast spin-echo imaging of the hippocampus: sequence optimization. J Magn Reson Imaging 1995; 5:309-15. [PMID: 7633108 DOI: 10.1002/jmri.1880050315] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Three-dimensional (3D) fast spin-echo (FSE) imaging can produce contiguous thin sections for high-quality multiplanar reconstructions. Such reformatted images may be useful in the evaluation of three-dimensionally complex, curvilinear anatomic structures such as the hippocampus. The authors describe a 3D FSE protocol for T2-weighted imaging of the hippocampus. The protocol uses an overlapping-multiple-slab imaging strategy to decrease imaging times and a modified refocusing radio-frequency pulse train to improve the reformatted images. The authors describe their parameter optimization, discuss the benefits and limitations of the new sequence, and present representative images of healthy volunteers.
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266
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Nghiem HV, Winter TC, Mountford MC, Mack LA, Yuan C, Coldwell DM, Althaus SJ, Carithers RL, McVicar JP, Freeny PC. Evaluation of the portal venous system before liver transplantation: value of phase-contrast MR angiography. AJR Am J Roentgenol 1995; 164:871-8. [PMID: 7726039 DOI: 10.2214/ajr.164.4.7726039] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE The purpose of this study was to assess the accuracy of phase-contrast MR angiography with gadolinium in evaluating the patency and blood flow direction of the portal venous system; the presence, extent, and type of varices; and the patency of surgical decompressive shunts in patients before liver transplantation. This information is essential in management and care of patients with chronic liver disease and portal hypertension and those who are candidates for liver transplantation. SUBJECTS AND METHODS Twenty-four patients with portal venous hypertension were evaluated with phase-contrast MR angiography. Two patients had surgical splenorenal shunts and one had a mesocaval shunt. Phase-contrast angiograms were acquired as a series of two-dimensional sequential coronal sections during breath-holding and after IV administration of gadopentetate dimeglumine. Correlative findings from color flow Doppler sonography, contrast-enhanced CT scanning, and conventional angiography were available in 23, 20, and 10 patients, respectively, and were used as standards. The images from each technique were analyzed independently for patency of and flow direction in the portal vein, splenic vein, superior mesenteric vein, and surgically created shunts, and for detection, distribution, and extent of five variceal groups. RESULTS Findings from phase-contrast MR angiography completely agreed with those of sonography, CT scanning, and conventional angiography. The main portal vein was patent in 18 patients, stenosed in one, partially thrombosed in one, and occluded in four. Phase-contrast MR angiography correctly showed hepatofugal flow in three patients and hepatopetal flow in 17 patients. Both the splenic and superior mesenteric veins were patent in 20, partially thrombosed in one, and occluded in three cases. Phase-contrast MR angiograms showed 85% of the variceal groups, and MR rating of variceal size was not significantly different from that of CT rating. Phase-contrast MR angiography correctly showed the patency of all three surgical decompressive shunts. CONCLUSION Phase-contrast MR angiography is accurate for evaluating the patency and flow direction of the portal venous system, detecting and determining the distribution and extent of varices, and assessing the patency of surgically created shunts. Therefore, it is a reliable and noninvasive technique that can provide crucial information in the preoperative workup of liver transplant recipients.
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267
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Skinner MP, Yuan C, Mitsumori L, Hayes CE, Raines EW, Nelson JA, Ross R. Serial magnetic resonance imaging of experimental atherosclerosis detects lesion fine structure, progression and complications in vivo. Nat Med 1995; 1:69-73. [PMID: 7584956 DOI: 10.1038/nm0195-69] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A major problem in the study of lesions of atherosclerosis is the difficulty of imaging noninvasively the lesions and following their progression in vivo. To address this problem, we have developed advanced magnetic resonance techniques to noninvasively and serially image advanced lesions of atherosclerosis in the rabbit abdominal aorta. Both lumen and wall were imaged with high resolution. Progression of disease, resulting in increase in lesion mass, decrease in arterial lumen, or stenosis, and intralesion complications, can be detected. Images acquired in vivo correlate with the fine structure of the lesions of atherosclerosis, including the fibrous cap, necrotic core, and lesion fissures, as verified by gross examination, dissection microscopy, and histology. The ability to noninvasively identify the features of atherosclerotic plaques, has significant implications for determining risks and benefits associated with different therapeutic approaches.
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268
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Jonas RE, Yuan C, Ebrey TG. Improved large-scale purification of transducin, and its alpha and beta gamma subunits from frozen retinas. PREPARATIVE BIOCHEMISTRY 1994; 24:279-88. [PMID: 7831208 DOI: 10.1080/10826069408010099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The transducin heterotrimer and its alpha- and beta gamma-subunits have been purified from frozen bovine rod outer segments by modifying existing procedures. The methods described here are relatively simple and fast. The yield (ca. 8 mgs/100 retinas) and purity of the transducin heterotrimer and subunits from frozen retinas is equal to or larger than those previously obtained from fresh or frozen retinas.
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Abstract
Cocaine can produce both positive and negative inotropy. The mechanism of cocaine-induced negative inotropy is poorly understood. In order to evaluate the inhibitory effect of cocaine on myocardial contractility, its action on potassium chloride-induced depolarization, release of calcium from sarcoplasmic reticulum, and sarcolemmal sodium-calcium exchange were studied. At a relatively high concentration (10(-3) M), cocaine significantly blocked an elevation of cytosolic calcium during potassium chloride-induced depolarization and significantly inhibited the release of calcium from sarcoplasmic reticulum by caffeine. In contrast, a much lower concentration of cocaine (10(-7) M) significantly reduced sarcolemmal sodium-calcium exchange. Our results suggest that the negative inotropic action of cocaine may be related to a concentration-dependent effect: higher concentrations may inhibit calcium release from sarcoplasmic reticulum and block calcium influx across the sarcolemma. In contrast, lower concentrations would lead to a positive inotropic effect because of an impaired sarcolemmal sodium-calcium exchanger.
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Malkawi E, Yuan C. Global analysis of the top quark couplings to gauge bosons. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 50:4462-4477. [PMID: 10018085 DOI: 10.1103/physrevd.50.4462] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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271
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Ladinsky GA, Yuan C. Nonperturbative regime in QCD resummation for gauge boson production at hadron colliders. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 50:R4239-R4243. [PMID: 10018119 DOI: 10.1103/physrevd.50.r4239] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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272
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Nghiem HV, Freeny PC, Winter TC, Mack LA, Yuan C. Phase-contrast MR angiography of the portal venous system: preoperative findings in liver transplant recipients. AJR Am J Roentgenol 1994; 163:445-50. [PMID: 8037047 DOI: 10.2214/ajr.163.2.8037047] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Sequential two-dimensional phase-contrast MR angiography can be used to accurately evaluate the anatomy, patency, and flow direction of the portal venous system and the presence, extent, and distribution of portosystemic collaterals. Its large field of view, insensitivity to the patient's body habitus, and graphic display format make this MR technique extremely useful for preoperative evaluation of patients with chronic liver disease and portal hypertension. This pictorial essay illustrates the spectrum of abnormalities seen on phase-contrast MR angiography of the portal venous system in patients with endstage liver diseases and portal hypertension.
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Ladinsky GA, Yuan C. Probe of new physics in top-quark pair production at e-e+ colliders. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 49:4415-4426. [PMID: 10017444 DOI: 10.1103/physrevd.49.4415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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274
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Bagger J, Barger V, Cheung K, Gunion J, Han T, Ladinsky GA, Rosenfeld R, Yuan C. Strongly interacting WW system: Gold-plated modes. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1994; 49:1246-1264. [PMID: 10017096 DOI: 10.1103/physrevd.49.1246] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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275
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Yuan C, Tsuruda JS, Beach KN, Hayes CE, Ferguson MS, Alpers CE, Foo TK, Strandness DE. Techniques for high-resolution MR imaging of atherosclerotic plaque. J Magn Reson Imaging 1994; 4:43-9. [PMID: 8148555 DOI: 10.1002/jmri.1880040111] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.
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276
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Yuan C, Schmiedl UP, Weinberger E, Krueck WR, Rand SD. Three-dimensional fast spin-echo imaging: pulse sequence and in vivo image evaluation. J Magn Reson Imaging 1993; 3:894-9. [PMID: 8280980 DOI: 10.1002/jmri.1880030617] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Three-dimensional (3D) magnetic resonance imaging allows thin-section acquisition and therefore more accurate multiplanar reconstruction than conventional two-dimensional spin-echo imaging. Unfortunately, addition of a third acquisition plane extends imaging time greatly. With gradient-echo techniques, 3D acquisitions have become clinically useful. These techniques are limited, however, by susceptibility and other field inhomogeneity artifacts and decreased signal-to-noise ratios compared with spin-echo techniques. The authors describe implementation of a true spin-echo 3D technique that, by using fast spin-echo parameters, reduces acquisition time to a clinically useful level. Potential applications of the technique are demonstrated.
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Naculich SG, Yuan C. Inelastic channels in WW scattering. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1993; 48:1097-1103. [PMID: 10016343 DOI: 10.1103/physrevd.48.1097] [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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278
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Chen S, Yuan C, Clough D, Schooley J, Haddy FJ, Pamnani MB. Role of digitalis-like substance in the hypertension of streptozotocin-induced diabetes in reduced renal mass rats. Am J Hypertens 1993; 6:397-406. [PMID: 8390268 DOI: 10.1093/ajh/6.5.397] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We have previously reported that chronic hypertension develops consistently in Wistar rats with a 25% reduction in renal mass (RRM) following the induction of insulin dependent diabetes mellitus (IDDM) with streptozotocin (STZ, 65 mg/kg body weight, intravenously). In this study, we examined the role of the endogenous digitalis-like substance in the development of hypertension. Four groups of rats were studied: 1) 25% RRM rats with STZ-induced IDDM (25-DM), 2) normal rats with STZ-induced IDDM (2K-DM), 3) 25% RRM rats with vehicle treatment (25-V), and 4) normal rats with vehicle treatment (2K-V). In 25-DM rats, blood pressure progressively increased during the 3 weeks after STZ treatment and was associated with microalbuminuria, low plasma renin activity, and extracellular volume expansion. In contrast, the 2K-DM, 25-V, and 2K-V rats remained normotensive. Furthermore, the plasma and urine levels of digoxin-like immunoreactive factor (DIF), determined by digoxin radioimmunoassay (Baxter), were significantly higher in hypertensive 25-DM rats than in their controls. The same was the case for plasma digitalis-like substance (DLS), determined by exposing canine Na+,K(+)-ATPase to plasma fractions and observing the percent inhibition. Increased DIF and DLS in hypertensive 25-DM rats was associated with a significant decrease in Na+,K(+)-ATPase activity of microsomes prepared from the left and right ventricles, when compared with microsomes from normotensive 2K-DM animals. Microsomal 5'-nucleotidase, a plasma membrane marker, was unchanged. The DIF and DLS correlated significantly with each other and with myocardial Na+,K(+)-ATPase activity and mean blood pressure. These results suggest that increased endogenous digitalis-like substance, which inhibits cardiovascular muscle cell Na(+)-K(+)-pump activity, may be involved in the mechanism of hypertension associated with IDDM in 25% RRM rats.
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Liu S, Wnuk SF, Yuan C, Robins MJ, Borchardt RT. Adenosine-5'-carboxaldehyde: a potent inhibitor of S-adenosyl-L-homocysteine hydrolase. J Med Chem 1993; 36:883-7. [PMID: 8464042 DOI: 10.1021/jm00059a013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Adenosine-5'-carboxaldehyde (3) and its 4'-epimer (4) were synthesized and shown to be potent type I mechanism-based inhibitors of recombinant rat liver AdoHcy hydrolase with k2/KI values of 16.7 x 10(-3) and 5.5 x 10(-3) nM-1 min-1, respectively. The observation that 3 and 4 are potent inhibitors of AdoHcy hydrolase supports the hypothesis that they function as key intermediates in the mechanism by which the (Z)- and (E)-4',5'-didehydro-5'-deoxy-5'-fluoroadenosines 1 and 2 inactivate this enzyme.
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Jun L, Mei Z, Yuan C. Reversal of inhibition of reactive oxygen species on respiratory burst of macrophages by polysaccharide from Coriolus versicolor. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 1993; 15:429-33. [PMID: 8505152 DOI: 10.1016/0192-0561(93)90055-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Using a luminol-dependent, chemiluminescence assay we found tert-butylhydroperoxide to be a strong inhibitor of the respiratory burst of mouse peritoneal macrophages. However, the inhibition of respiratory burst induced by tert-butylhydroperoxide could be prevented after the interperitoneal injection of polysaccharide from Coriolus versicolor (PSK). Further investigation showed that glutathione peroxidase activity was markedly elevated in PSK-treated macrophages. After incubation with tert-butylhydroperoxide, higher activity of glutathione peroxidase was maintained in PSK-treated macrophages. These results suggest that the immunological function of macrophages is related to the activity of glutathione peroxidase. The non-specific immunopolysaccharide might protect macrophages from the damage induced by reactive oxygen species by enhancing antioxidative capacity.
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Yuan C, Manunta P, Chen S, Hamlyn JM, Haddy FJ, Pamnani MB. Role of ouabain-like factors in hypertension: effects of ouabain and certain endogenous ouabain-like factors in hypertension. J Cardiovasc Pharmacol 1993; 22 Suppl 2:S10-2. [PMID: 7508010 DOI: 10.1097/00005344-199322002-00005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Several reports suggest the presence of sodium-potassium pump inhibitor in plasma and various tissues, particularly during volume-expanded state and low-renin hypertension. It has been hypothesized that by inhibiting the cardiovascular muscle-cell Na(+)-K+ pump, this inhibitor can constrict blood vessels, enhance vasoconstriction, and increase cardiac contractility, thereby raising blood pressure. Only two such endogenous inhibitors have been chemically characterized: the bufodienolide derivative, resibufogenin, obtained from toad skin and plasma; and a factor with the same structure (based on mass spectral analysis) as ouabain, from human plasma. However, unlike bufalin (aglycone), which is almost structurally identical to resibufogenin, neither ouabain nor ouabagenin (aglycone of ouabain) caused a sustained increase in blood pressure when infused in equimolar doses during a 30-min period in rats. Because the rat is 10(4)-fold less sensitive to ouabain than the human is, we wondered whether the absence of a response to ouabain was due to the short infusion time. Therefore, in new experiments ouabain was administered chronically during a 6- to 7-week period to two-kidney normal rats and rats with 70, 60, and 25% reduced renal mass. Reduced renal mass rats were used because these rats have decreased sodium excretion capacity, and thus we hoped the action of exogenous ouabain would be potentiated in these volume-expanded rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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282
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Atkins JL, Yuan C, Chen S, Pamnani M. Renal lymphatic obstruction in diabetic rats induces systemic hypotension. Ren Fail 1993; 15:33-6. [PMID: 8441834 DOI: 10.3109/08860229309065569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We obstructed renal lymph drainage from a single kidney in diabetic rats who had received 65 mg/kg streptozotocin 6 months prior to the study. Lymphatic obstruction led to a progressive fall in systematic blood pressure from a mean arterial pressure of 101 +/- 5 (SEM) mm Hg (n = 7) to 62 +/- 4 mm Hg (n = 5) (p < .02) after 1.5 h. No change was seen in a sham-operated animal. Despite the decline in systemic blood pressure there was no significant change in the GFR of either kidney. Sodium excretion increased significantly in the experimental kidney. There was no change in the urinary excretion of cyclic GMP from either kidney, and plasma levels of atrial natriuretic peptide (ANP) did not change (55 +/- 21 pg/mL pre- to 64 +/- 18 postobstruction). The results are consistent with a systemic vasodilatation after lymphatic obstruction. The mechanism of this response is still under investigation, but apparently it does not involve ANP.
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283
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Chen S, Yuan C, Clough D, Haddy FJ, Pamnani MB. Role of digitalis-like substance in experimental insulin-dependent diabetes mellitus hypertension. J Cardiovasc Pharmacol 1993; 22 Suppl 2:S20-1. [PMID: 7508018 DOI: 10.1097/00005344-199322002-00008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hypertension is frequently associated with insulin-dependent diabetes mellitus, but the mechanism of the hypertension is unknown. An animal model of insulin-dependent diabetes mellitus hypertension could be helpful in determining the mechanism, but experimental insulin-dependent diabetes mellitus has been infrequently and irregularly associated with hypertension. In an attempt to develop a dependable model of insulin-dependent diabetes mellitus hypertension, we studied seven series of rats receiving either streptozotocin, surgical reduction of renal mass, or both. We found that superimposing streptozotocin 65 mg/kg body weight on 25% reduced renal mass regularly produced insulin-dependent diabetes mellitus and low-renin volume-expanded hypertension and that the animals remained healthy and hypertensive for as long as followed (13 weeks). Microalbuminuria correlated temporally with blood pressure. We used this dependable model to examine the role of endogenous digitalis-like substance in the development of hypertension in insulin-dependent diabetes mellitus. Plasma levels of digoxin-like immunoreactive factor (DIF), determined with a digoxin radioimmunoassay, were significantly higher in these hypertensive rats than in normotensive control rats (two-kidney diabetic rats, 25% reduced renal mass rats receiving vehicle for streptozotocin). This increase in plasma DIF was associated with a decrease in Na+, K(+)-ATPase activity in microsomes prepared from left or right ventricle. Microsomal 5'-nucleotidase, a plasma membrane marker, was unchanged. The plasma DIF level correlated inversely with myocardial Na+, K(+)-ATPase activity and positively with systolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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284
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Tang X, Yuan C, Zhang Z, Zhou M. [Chemical constituents of Bauhinia hupehara Craib]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:613-5, 640. [PMID: 1294179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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285
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Chen S, Yuan C, Schooley JF, Haddy FJ, Pamnani MB. A consistent model of insulin-dependent diabetes mellitus hypertension. Am J Hypertens 1992; 5:671-80. [PMID: 1418828 DOI: 10.1093/ajh/5.10.671] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Hypertension is frequently seen in insulin-dependent diabetes mellitus (IDDM), but the mechanism of the hypertension is unknown. An animal model of IDDM hypertension could be helpful in determining the mechanism, but experimental IDDM has been infrequently and irregularly associated with hypertension. In an attempt to develop a consistent model of IDDM hypertension, we superimposed streptozotocin (STZ)-induced IDDM on surgical reduction of renal mass (RRM) in Wistar rats. Seven groups of rats were studied: 1) 60% RRM receiving 65 mg/kg body weight (BW) STZ; 2) 60% RRM receiving 40 mg/kg BW STZ; 3) 25% RRM receiving 65 mg/kg BW STZ; 4) two kidney normal rats receiving 65 mg/kg BW STZ; 5) 60% RRM receiving vehicle (control for group 1); 6) 60% RRM receiving vehicle (control for group 2); and 7) 25% RRM receiving vehicle. STZ produced diabetes and hypertension within 1 to 2 weeks in all three groups of RRM rats but blood pressure was unaffected by 60% or 25% RRM alone. STZ alone had no effect on blood pressure until the 5th week when the blood pressure increased slightly. Progressive weight loss resulted from 65 mg/kg BW STZ combined with 60% RRM; the animals had to be terminated after 5 weeks. In only 60% of animals with 40 mg/kg BW STZ plus 60% RRM was IDDM produced. On the other hand, 65 mg/kg BW STZ in rats with 25% RRM regularly produced IDDM and hypertension without excessive loss of body weight. In these rats, albuminuria developed in 2 weeks. Extracellular fluid volume was elevated and plasma renin activity was depressed. The animals were healthy and hypertensive when killed at the 13th week. We suggest that the 25% RRM rat receiving 65 mg/kg BW STZ is a consistent model of IDDM hypertension, which may be useful in probing the mechanism of this type of hypertension.
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286
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Mrenna S, Yuan C. QCD radiative decay of the top quark produced in hadron collisions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 46:1007-1021. [PMID: 10015016 DOI: 10.1103/physrevd.46.1007] [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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287
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Yuan C. [Analysis of factors influencing on the surgical results of arterial embolism in the lower extremities]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1992; 30:427-30, 445. [PMID: 1301348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
130 patients with arterial embolism in the lower extremities underwent surgical treatment. The curative rate was 66.9%, amputation rate-19.2% and the mortality rate-13.8%. Statistical study showed that sex, age and recurrent embolism had few effects on the surgical results (P < 0.05). One of the influencing factors was the ischemic time of the lower extremities. The mortality rate was 33.3% in the distal abdomen with aortic embolism and 8.7% in the lower extremities (P < 0.005). The mortality rate and amputation rate were significantly higher in embolic patients with atherosclerotic stenosis and occlusion (9% and 17%). The mortality rate and amputation rate were 2.3% and 3.4% in patients with good blood flow and were 42.1% and 57.9% in patients without good blood flow uspectively. Reembolectomies showed no satisfactory effect. The results indicated that embolectomy combined with other necessary operations did not increase the mortality rate and amputation rate (P < 0.05). Postoperative anticoagulation therapy is extremely important.
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288
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Xue Y, Zhang H, Wang N, Yuan C. [Chemical constituents of the roots of Ostericum grosseserratum (Maxim.) Kitag]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:354-6, 383. [PMID: 1418580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This paper reports the isolation of eleven compounds from the roots of Ostericum grosseserratum, of which nine compounds were elucidated as myristic acid, palmitic acid, stearic acid, octacosanoic acid, succinic acid, beta-sitosterol, sitosterol-beta-D-glucoside, isoscopletin and sucrose. The results are helpful in the study of plant taxonomy.
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289
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He S, Wen T, Ding H, Huang X, Yuan C, Zhang X, Chen D, Yang C. [Hepatic segmentectomy using microwave tissue coagulator]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1992; 23:209-12. [PMID: 1452161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hepatic segmentectomy using a microwave tissue coagulator guided by intraoperative ultrasonography is a new operative procedure, which our research unit was the first to start using from 1990. Up to now we have performed this kind of operation with success in 26 cases. Our results suggested that the new procedure simplified the original operation and greatly reduced the risk of hemorrhage and iatrogenic spread of the cancer cells during operation. Besides, this operation as a kind of definite anatomic hepatectomy can minimally resect the tumor bearing tissue in a radical fashion, while maximally preserve the tumor-free tissue of the liver.
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290
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Yuan C, Yue J, Wang N, Lu Y, Guo K. [Evaluation of rare and endangered conservational medicinal plants in Jiangsu Province]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:130-3, 191. [PMID: 1418535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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291
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Wang N, Yuan C, Lu Y, Yue J, Guo K. [Discussion on criteria for appraising the endanger threatening rare medicinal plants]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:67-70, 125. [PMID: 1418527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This paper deals with the criteria for appraising the endanger threatening rare medicinal plants. A preliminary evaluating method is presented.
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292
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Yuan C. Top-quark polarization at e-e+ colliders. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 45:782-793. [PMID: 10014436 DOI: 10.1103/physrevd.45.782] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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293
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Yuan C, Wang N, Lu Y. [Imperativeness of strengthening conservation and management of resources of Chinese medicinal materials]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1992; 17:3-5, 62. [PMID: 1524662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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294
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Kim CS, Rosner JL, Yuan C. Erratum: Impact of new ||Vub/Vcb|| and epsilon '/ epsilon measurements on weak mixing angles. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 45:389. [PMID: 10014225 DOI: 10.1103/physrevd.45.389] [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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295
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Kane GL, Ladinsky GA, Yuan C. Using the top quark for testing standard-model polarization and CP predictions. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1992; 45:124-141. [PMID: 10014197 DOI: 10.1103/physrevd.45.124] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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296
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Guo Y, Cha M, Chao A, Yuan C. [Determination of aucubin in Plantago asiatica L., P. major L. and P. depressa Willd. by HPLC]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:743-4, 763. [PMID: 1811672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A HPLC method for the determination of aucubin in P. asiatica, P. major and P. depressa was established. The mobile phase is MeOH-H2O (17:83). Good in producibility and high in rate of recovery, this method provides an effective way for the study of Plantago.
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297
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Yuan C, Yuan TC. Leading electroweak radiative corrections to t-->W++b. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1991; 44:3603-3609. [PMID: 10013822 DOI: 10.1103/physrevd.44.3603] [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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298
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Zhang Y, Sha D, Sha M, Yuan C. [Determination of glaucocalyxin A in the leaves of Plectranthus japonicus (Burm.) Koidz. var. glaucocalyx (Maxim.) Koidz. by HPLC]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:679-80, 704. [PMID: 1804175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This paper reports the quantitative analysis of glaucocalyxin A in the leaves of Plectranthus japonicus var. glaucocalyx by HPLC. The chromatographic conditions were as follows: column: Shim-pack CLC-ODS; mobile phase: methanol-water (70:30). The average content of glaucocalyxin A in the leaves is 1.30%.
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299
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Zhao Y, Yuan C, Lu H. [Isolation and identification of 20(R)-ginsenoside-Rh2 (an anti-cancer constituent) from the fruits of Panax ginseng. C.A. Meyer]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:678-9, 704. [PMID: 1804174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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300
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Chen R, Yuan C. [Experimental anti-arrhythmic effects of zhigancao (prepared licorice) injection]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1991; 16:617-9, inside back cover. [PMID: 1820795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Zhigancao injection can antagonise the arrhythmia induced by chloroform, adrenaline, aconitine, strophanthine K and barium chloride, slow the heart rate, prolong P-R and Q-T intervals and antagonise the positive chronotropic response induced by isoprenaline. The LD50 of zhigancao injection is 41.2g/kg in nice by intraperitoneal.
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