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Yuan C, Acosta D. Effect of cocaine on mitochondrial electron transport chain evaluated in primary cultures of neonatal rat myocardial cells and in isolated mitochondrial preparations. Drug Chem Toxicol 2000; 23:339-48. [PMID: 10826100 DOI: 10.1081/dct-100100119] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cardiotoxicity is commonly associated with cocaine abuse. Previous studies have indicated that cocaine alters myocardial mitochondrial function. This study was undertaken to investigate the effect of cocaine on activity of the mitochondrial electron transport chain in cultures of neonatal rat cardiomyocytes and in isolated myocardial mitochondria. Cocaine concentrations (10(-5) to 10(-3) M) were used, and these concentrations have been reported in human cocaine users and are within a similar range of cocaine concentrations used in studies in vivo. After 24 hr treatment of cocaine, there was a slight increase in lactate dehydrogenase leakage in the cells treated with cocaine (10(-3) M). Reduction of tetrazolium compounds, neotetrazolium chloride (NTC) and triphenyltetrazolium chloride (TTC) was analyzed in intact cells to assess activity of the mitochondrial electron transport chain. Cocaine (10(-3) M) did not significantly change TTC and NTC reduction. In isolated mitochondria, cocaine (10(-3) M) significantly inhibited glutamate/malate-mediated respiration. These data suggest that cocaine at high concentrations may inhibit complex I of the mitochondrial electron transport chain of myocardial cells.
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Yuan C, Kadiiska M, Achanzar WE, Mason RP, Waalkes MP. Possible role of caspase-3 inhibition in cadmium-induced blockage of apoptosis. Toxicol Appl Pharmacol 2000; 164:321-9. [PMID: 10799343 DOI: 10.1006/taap.2000.8921] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cadmium (Cd) and chromium (Cr) are human carcinogens. Cr(VI) is taken up into cells and reduced by cellular reductants to the potential DNA damaging species Cr(V), (IV), and (III). Reactive oxygen species and carbon-based radicals may also be produced during Cr reduction. We previously found that Cd blocks Cr-induced apoptosis, which could allow a larger proportion of genetically damaged cells to escape and become transformed. This study helped define the mechanisms of Cd-induced suppression of apoptosis. Chinese hamster ovary (CHO K1-BH4) cells were treated with either Cd (5-20 microM), Cr(VI) (350 microM), or Cd (5-20 microM) plus Cr(VI) (350 microM) for 3 h and then cultured in metal-free media for an additional 48 h at which time DNA was extracted or nuclei were examined to determine apoptosis. Cd markedly reduced Cr-induced DNA fragmentation and reduced the number of Cr-induced apoptotic cell nuclei to control levels. Additional study investigated the biokinetics and cellular metabolism of Cr. Cd did not alter the cellular Cr accumulation and there were no differences in the levels of reduced glutathione, a compound possibly important in Cr reduction and reflective of the cellular reducing environment. The antiapoptotic effect of Cd was not due to diminished cellular reduction of Cr(VI) as assessed by electron-spin resonance determination of the levels of Cr(V). Thus, Cd suppression of Cr-induced apoptosis is not based on altered Cr toxicokinetics or metabolism. In addition to Cr, Cd also inhibited apoptosis induced by hygromycin B and actinomycin D. Cd was a very effective inhibitor of caspase-3 activity, a central mediator of apoptosis, with nontoxic levels of Cd resulting in up to approximately 60% inhibition. These results indicate that Cd may have a generalized inhibitory effect on apoptosis, possibly by inhibiting caspase-3. Inhibition of apoptosis by Cd may allow a greater portion of genetically damaged cells to survive, or give selective growth advantages, and has implications as a potential nongenotoxic mechanism of Cd carcinogenesis.
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Zhao J, Yuan C, Wang D, Li X. Mannitolum infusion on cirrhotic patients with tense ascites treated by paracentesis. Chin Med J (Engl) 2000; 113:27-30. [PMID: 11775204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
OBJECTIVE To investigate whether albumin can be substituted by mannitolum in cirrhotic patients with tense ascites treated by paracentesis. METHODS Sixty-eight patients admitted to this therapeutic procedure were randomly assigned to receive intravenous albumin (36 patients) and mannitolum (32 patients) infusion. In repeated large-volume paracentesis (3-6 L/day), intravenous albumin 20 g or intravenous 20% mannitolum 250 ml were added. RESULTS In 24 and 48 hours after paracentesis the mean value of electrolytes, liver and renal functions and various indicators of systemic circulation either in Group 1 or in Group 2 cases were found without changes (P > 0.05). As compared with that before paracentesis, the diameter of spleen vein was increased significantly (P < 0.05). The complications occurring after paracentesis were similar in both groups. CONCLUSIONS It was suggested that paracentesis with intravenous infusion of mannitolum is an effective and safe method in treating cirrhotic patients with tense ascites.
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Li X, Yuan C, Sun G, Lu Z. [Determination of 5-FU in serumand tissues after nebulization in patients with lung cancer.]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 1999; 2:93-94. [PMID: 20929639 DOI: 10.3779/j.issn.1009-3419.1999.02.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND To observe the distribution of 5-FU in serum and respiratory system after nebulization in patients with lung cancer. METHODS Ten patients with lung cancer were given 40 ml of 1. 25 % 5-FU by nebulization twice every day. At the same time , other 10 patients with lung cancer , chosen as control group , were given 0. 75g of 5-FU intravenously once every day. The concentration of 5-FU in serum and respiratory systemwas determined by chromatography. RESULTS The highest concentration of serum 5-FU was (4. 59 +/-1. 77)mg/L in nebulization group and (10. 46 +/-1. 46)mg/L in control group respectively ( P < 0. 001) . Compared with the control group , the 5-FU concentration for nebulization group was remarkably higher in main bronchi ( P < 0. 05) . The 5-FU concentration in peripheral lung and hilar lymph nodes and tumor tissue had no significant difference for both groups ( P > 0. 05) . CONCLUSIONS The 5-FU concentration was significantly higher in respiratory system and lower in serum by nebulization than by injection. Nebulization can lessen the toxic reaction and offer a safe and effective route for chemotherapy.
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He N, Kuang Y, Dai Q, Miao Y, Zhang A, Wang X, Song K, Lu Z, Yuan C. Growth of carbon nanotubules on Fe-loading zeolites and investigation of catalytic active center. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 1999. [DOI: 10.1016/s0928-4931(99)00017-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Yuan C, Tsai M. Pancreatic phospholipase A(2): new views on old issues. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1441:215-22. [PMID: 10570249 DOI: 10.1016/s1388-1981(99)00156-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The recent development in the structure-function relationship of pancreatic phospholipase A(2) is reviewed. The results of extensive studies by a combination of site-directed mutagenesis, X-ray crystallography, and NMR have provided new insight into several old issues. In particular, we summarize current views on the active site, the interfacial binding site, the mechanism of interfacial activation, the roles of the hydrogen-bonding network and the catalytic dyad, and the conformational stability of the structure.
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Yuan C, Li J, Selby TL, Byeon IJ, Tsai MD. Tumor suppressor INK4: comparisons of conformational properties between p16(INK4A) and p18(INK4C). J Mol Biol 1999; 294:201-11. [PMID: 10556039 DOI: 10.1006/jmbi.1999.3231] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The INK4 (inhibitor of cyclin-dependent kinase 4) family consists of four tumor-suppressor proteins: p15(INK4B), p16(INK4A), p18(INK4C), and p19(INK4D). While their sequences and structures are highly homologous, they show appreciable differences in conformational flexibility, stability, and aggregation tendency. Here, p16 and p18 were first compared directly by NMR for line broadening and disappearance, then investigated by three different approaches in search of the causes of these differences. From denaturation experiments it was found that both proteins are marginally stable with low denaturation stability (1.94 and 2.98 kcal/mol, respectively). Heteronuclear (1)H-(15)N nuclear Overhauser enhancement measurements revealed very limited conformational flexibility on the pico- to nanosecond time-scale for both p16 and p18. H/(2)H exchange of amide protons monitored by NMR on three proteins (p16, p18 as well as p15), however, revealed markedly different rates in the order p18<p16</=p15. A subset of very slowly exchanging residues (about 19 in total) was identified in p18, including 16 residues in the region of the fourth ankyrin repeat, probably as a result of a stabilizing effect by the extra ankyrin repeat. Thus, while INK4 proteins may have similar low thermodynamic stability as well as limited flexibility on the pico- to nanosecond time-scale, they display pronounced differences in the conformational flexibility on the time-scale of minutes to hours. Further analyses suggested that differences in H/(2)H exchange rates reflect differences in the kinetic stability of the INK4 proteins, which in turn is related to differences in the aggregation tendency.
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Liu X, Zhang Z, Yan L, Jiang J, Yuan C, Jin L, Huang Z, Hu W, Chen G, Li Q, Zhang G, Tian B, Wu H. [Clinical protocols for the treatment of severe acute pancreatitis]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1999; 37:660-2. [PMID: 11829919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To set up principles for the treatment of severe acute pancreatitis (SAP). METHODS The therapeutic principles and results of SAP in three periods were analyzed. Period I (1980 - 1990) was characterized by early surgical intervention supplemented with integrated traditional and western medical therapy, period II (1991 - 1993) by integrated traditional and western medical therapy supplemented with surgery for early complications, and period III (1994 - 1997) by integrated traditional and western medical therapy supplemented with surgery for local infectious complications only. RESULTS Because of the improvement of intensive care, the operation rates kept declining in the three periods. They were 77.59%, 54.55% and 29.55% with a mortality rate of 40.52%, 17.17% and 11.36%, respectively. CONCLUSIONS Integrated traditional and western medicine has been effective in most SAP patients, and surgery is indicated only for late complications such as necrotizing infection. Early surgery should be restricted.
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Guo Z, Yuan C, Wei-Lavery T, Fang Y, Garvin RA, Nishida HI, Nishida T. Secretion of phospholipid transfer protein by human hepatoma cell line, Hep G2, is enhanced by sodium butyrate. J Nutr 1999; 129:1984-91. [PMID: 10539773 DOI: 10.1093/jn/129.11.1984] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hep G2 cells were used to study the synthesis and secretion of phospholipid transfer protein (PLTP). Upon incubation of the cells at confluence with serum-free Dulbecco's modified Eagle's medium (DMEM), phosphatidylcholine (PC) transfer activity was found to accumulate in the culture media. The PC transfer activity in the media was effectively inhibited by rabbit anti-human PLTP immunoglobulin (Ig)G, thus indicating that the PC transfer activity was due to secreted PLTP. The molecular weight of Hep G2 PLTP was approximately 78 kDa by Western blot analysis, in agreement with the molecular weight obtained for purified human plasma PLTP. The PLTP secreted by Hep G2 also possessed an HDL conversion activity similar to that of human plasma PLTP. The addition of butyrate to the cell culture media resulted in a marked increase in the secretion of PLTP. After 24 h incubation with 4 mmol/L sodium butyrate, a more than twofold increase (P < 0.01) of PC transfer activity in the cell-conditioned media was obtained. The dose-dependent increase in the PC transfer activity in the media upon butyrate treatment was well correlated (r = 0.80, P < 0.01) with that of PLTP mass as determined by immuno-slot blot analysis of cell-conditioned media. The increased secretion of PLTP by Hep G2 treated with sodium butyrate was accompanied by a greater increase in the level of PLTP mRNA in the cells as determined by ribonuclease protection assay. In the presence of 4 mmol/L sodium butyrate, a fourfold increase (P < 0. 01) in mRNA level was obtained at 24 h. No stabilizing effect of butyrate on PLTP mRNA was apparent upon treatment of the cultured cells with the RNA synthesis inhibitor, actinomycin D. Thus, the up-regulatory effect of butyrate on PLTP gene expression seemed to have occurred at the transcriptional level.
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Su B, Zhu Q, Gao K, Yuan C, Jia Z. Lignan and phenylpropanoid glycosides from Lancea tibetica and their antitumor activity. PLANTA MEDICA 1999; 65:558-561. [PMID: 10483379 DOI: 10.1055/s-1999-14026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new lignan glucoside, the first 7,9'-monoepoxyte-trahydrofuran type lignan with the cis-relationship of H-7 and H-8, named tibeticoside (1), as well as ten known compounds have been isolated from the medicinal plant (roots, stems and leaves) Lancea tibetica. The structure of tibeticoside (1) has been elucidated on the basis of chemical and spectral evidence, especially by 2D-NMR (1H-1H COSY, HMQC, HMBC, NOESY). In addition, sylvatesmin (6) exhibited effective antitumor activity on B16 cells.
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Huang L, Wang M, Fu G, Yang B, Wang N, Yuan C. [RAPD analysis of germplasm in "baizhi"]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1999; 24:457-9, 509-10. [PMID: 12205862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
OBJECTIVE To analyse the germplasm in Baizhi. METHOD Using 12 random primers, over seventeen individuals' RAPD were detected in four populations from wild Baizhi (Angelica dahurica), Qi Baizhi and Hang Baizhi. RESULTS A total of 40 loci were amplified, 26 of which were polymorphism(65%). The PPS values of Hang Baizhi and Qi Baizhi indicate their low levels of genetic diversity. According to the RAPDinstance analysis, the genetic distance(0.16) between Qi Baizhi and Hang Baizhi is shorter than that of the individuals of the populations of Qi Baizhi and Hang Baizhi, and all of these genetic distances are shorter than those between wild Baizhi and Hang Baizhi(Qi Baizhi). CONCLUSION Hang Baizhi- and Qi Baizhi belong to the same taxon, which is different from the wild Baizhi.
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Yuan C, Kuwata O, Liang J, Misra S, Balashov SP, Ebrey TG. Chloride binding regulates the Schiff base pK in gecko P521 cone-type visual pigment. Biochemistry 1999; 38:4649-54. [PMID: 10194387 DOI: 10.1021/bi9828977] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The binding of chloride is known to shift the absorption spectrum of most long-wavelength-absorbing cone-type visual pigments roughly 30 nm to the red. We determined that the chloride binding constant for this color shift in the gecko P521 visual pigment is 0.4 mM at pH 6.0. We found an additional effect of chloride on the P521 pigment: the apparent pKa of the Schiff base in P521 is greatly increased as the chloride concentration is increased. The apparent Schiff base pKa shifts from 8.4 for the chloride-free form to >10.4 for the chloride-bound form. We show that this shift is due to chloride binding to the pigment, not to the screening of the membrane surface charges by chloride ions. We also found that at high pH, the absorption maximum of the chloride-free pigment shifts from 495 to 475 nm. We suggest that the chloride-dependent shift of the apparent Schiff base pKa is due to the deprotonation of a residue in the chloride binding site with a pKa of ca. 8.5, roughly that of the Schiff base in the absence of chloride. The deprotonation of this site results in the formation of the 475 nm pigment and a 100-fold decrease in the pigment's ability to bind chloride. Increasing the concentration of chloride results in the stabilization of the protonated state of this residue in the chloride binding site and thus increased chloride binding with an accompanying increase in the Schiff base pK.
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Yuan C, Byeon IJ, Li Y, Tsai MD. Structural analysis of phospholipase A2 from functional perspective. 1. Functionally relevant solution structure and roles of the hydrogen-bonding network. Biochemistry 1999; 38:2909-18. [PMID: 10074343 DOI: 10.1021/bi982211a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bovine pancreatic phospholipase A2 (PLA2), a small (13.8 kDa) Ca2+-dependent lipolytic enzyme, is rich in functional and structural character. In an effort to examine its detailed structure-function relationship, we determined its solution structure by multidimensional nuclear magnetic resonance (NMR) spectroscopy at a functionally relevant pH. An ensemble of 20 structures generated has an average root-mean-square deviation (RMSD) of 0.62 +/- 0.08 A for backbone (N, Calpha, C) atoms and 0.98 +/- 0.09 A for all heavy atoms. The overall structure shows several notable differences from the crystal structure: the first three residues at the N-terminus, the calcium-binding loop (Y25-T36), and the surface loop (V63-N72) appear to be flexible; the alpha-helical conformation of helix B (E17-F22) is absent; helix D appears to be shorter (D59-V63 instead of D59-D66); and the hydrogen-bonding network is less defined. These differences were analyzed in relation to the function of PLA2. We then further examined the H-bonding network, because its functional role or even its existence in solution has been in dispute recently. Our results show that part of the H-bonding network (the portion away from N-terminus) clearly exists in solution, as evidenced by direct observation (at 11.1 ppm) of a strong H-bond between Y73 and D99 and an implicated interaction between D99 and H48. Analyses of a series of mutants indicated that the existence of the Y73.D99 H-bond correlates directly with the conformational stability of the mutant. Loss of this H-bond results in a loss of 2-3 kcal/mol in the conformational stability of PLA2. The unequivocal identification and demonstration of the structural importance of a specific hydrogen bond, and the magnitude of its contribution to conformational stability, are uncommon to the best of our knowledge. Our results also suggest that, while the D99.H48 catalytic diad is the key catalytic machinery of PLA2, it also helps to maintain conformational integrity.
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Yuan C, Byeon IJ, Poi MJ, Tsai MD. Structural analysis of phospholipase A2 from functional perspective. 2. Characterization of a molten globule-like state induced by site-specific mutagenesis. Biochemistry 1999; 38:2919-29. [PMID: 10074344 DOI: 10.1021/bi9822123] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previous NMR studies have shown that many phospholipase A2 (PLA2, from bovine pancreas, overexpressed in Escherichia coli) mutants display some properties reminiscent of a molten globule state. Further NMR analyses for some of the mutants indicated that formation of the "molten globule-like state" is a pH-dependent phenomenon. The mutants I9Y and I9F showed perturbed NMR properties throughout the pH range studied, while the mutants H48A and C44A/C105A displayed native-like spectra at neutral pH but molten globule-like ones under acidic conditions, with a "transition pH" around 4. On the other hand, wild-type PLA2 exhibits exceptional pH stability and turns into a similar molten globule-like state only under highly acidic conditions such as 1 M HCl. The H48A mutant was used to rigorously establish the property of the molten globule-like state of PLA2 mutants. The results of far-UV CD, near-UV CD, and ANS-binding fluorescence suggest that H48A retains native-like secondary structures but loses tertiary structure during the conformational transition. However, the tertiary structure is not completely lost, as evidenced by the retention of some long-range NOEs in two-dimensional NOESY spectra. The conclusion was further substantiated by three-dimensional NOESY-HSQC experiments on a 15N-labeled H48A sample. It was revealed that the molten globule-like state at mildly acidic pH retained some rigid tertiary structure, which consisted of partial alpha-helix II (Y52-L58), alpha-helix III (D59-V63), beta-wing (S74-S85) and partial alpha-helix IV (A90-N97). These residual tertiary structures grouped in half of the protein could be attributed to stabilization by some of the disulfide bonds. The extreme sensitivity of the PLA2 structure to site-directed mutagenesis is unprecedented. It is interesting to note that most of the functional residues (the active site, the hydrophobic channel, the interfacial binding site, and the calcium-binding loop) are located in the remainder of the protein, which is well disrupted in tertiary interactions.
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Pessa JE, Zadoo VP, Yuan C, Ayedelotte JD, Cuellar FJ, Cochran CS, Mutimer KL, Garza JR. Concertina effect and facial aging: nonlinear aspects of youthfulness and skeletal remodeling, and why, perhaps, infants have jowls. Plast Reconstr Surg 1999; 103:635-44. [PMID: 9950555 DOI: 10.1097/00006534-199902000-00042] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of aging on the orbitomaxillary region is evaluated in the present study. The observation was made that infants look like aged individuals in terms of the midface soft-tissue contours of the midface. Because preliminary work has shown that the facial skeleton remodels throughout life, this observation led to the hypothesis that infants and older individuals appear similar because they have comparable skeletal dimensions, specifically in the orbitomaxillary region. The design is a retrospective analysis of three-dimensional computed tomographic scan data. Three groups of male subjects were studied: infant, ages 1 to 12 months (n = 5); youthful, ages 15 to 24 years (n = 13); and old, ages 53 to 76 years (n = 12). Orbital and zygomaticomaxillary vertical dimensions were measured in both medial and lateral planes between fixed anatomical landmarks. Results were compared by using analysis of variance, Student-Newman-Keuls, and Student's t tests. The findings show that skeletal remodeling is such that the ratio of the maxillary height to orbital height is greatest during youth; during infancy and old age, there is a short maxilla relative to a larger orbit. This finding is significant in the medial plane from orbital rim to pyriform aperture (p < 0.05). Furthermore, there is an actual decrease in vertical maxillary height in this medial plane (p < 0.01) from youth until old age, which occurs secondary to normal skeletal remodeling in the dentate individual. The combined effect of downward expansion of the orbital shelf and the upward migration of the pyriform effectively decreases the space available to support the overlying soft tissues of the midface. An accordion-like or "concertina" effect may lead to compression or restriction of the facial soft tissues over a relatively deficient bony platform. These results highlight the importance of skeletal remodeling in determining the soft-tissue contours of the aging face. The process of skeletal remodeling may also allow for a tentative definition of facial youthfulness. Infants are born with a short maxilla relative to a large orbit, and the maxillary wall is angled posteriorly. This ratio and angle change from infancy until youth, when there is a balance between the bony skeletal support and the overlying soft-tissue envelope, i.e., the skin, facial muscles, and adipose tissue. It is when skeletal remodeling continues past this point that a disharmony occurs. Because the ratio of maxilla/orbit, and the angle of the maxillary wall, in the older person reverts toward that of an infant, the attainment of youth occurs partly in a nonlinear or multimodal manner. This work is part of an emerging concept of facial aging, which we would term an integrated model of facial aging. This model allows facial aging to be viewed as a biological "system," in which there are primary and secondary factors that interact in the process of facial aging. Additional research such as this continues to suggest the importance of bony remodeling in facial aging.
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Yuan C, Lin E, Millard J, Hwang JN. Closed contour edge detection of blood vessel lumen and outer wall boundaries in black-blood MR images. Magn Reson Imaging 1999; 17:257-66. [PMID: 10215481 DOI: 10.1016/s0730-725x(98)00162-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Quantitative measurements of the blood vessel wall area may provide useful information of atherosclerotic plaque burden, progression and/or regression. Magnetic resonance imaging is a promising technique for identifying both luminal and outer wall boundaries of the human blood vessels. Currently these boundaries are primarily defined manually, a process viewed as labor intensive and subject to significant operator bias. Fully automated post-processing techniques used for identifying the lumen and wall boundaries, on the other hand, are also problematic due to the complexity of signal features in the vicinity of the blood vessels. The goals of this study were to develop a robust, automated closed contour edge detection algorithm, apply this algorithm to high resolution human carotid artery images, and assess its accuracy, and reproducibility. Our algorithm has proven to be sensitive to various contrast situations and is reasonably accurate and highly reproducible.
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Liu J, Cai X, Lin J, Yang G, Shen X, Fu Z, Shi F, Shen W, Li M, Yuan C, Li H, Cai Y, Wu X. [Expression of Schistosoma japonicun fatty acid binding protein gene in silkworm cells and larvae]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 1999; 17:218-21. [PMID: 12563767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
AIM To express the fatty acid binding protein (Sj14FABP) gene of Schistosoma japonicun in the silkworm cells and larvae. METHODS A 600 bp DNA fragment containing Sj14FABP gene was cloned into baculovirus transfer vector of pBacPAK His1 to construct recombinant transfer vector Sj14-pBac PAK His1. Coinfection was accomplished with this vector and Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA in BmN cells. The recombinant virus of Bm-Sj14 was screened using dot-blotting. The BmN cells and silkworm larvae were infected with Bm-Sj14 to express Sj14FABF gene. Western blotting and ELISA were used to identify the antigenicity of the recombinant protein. RESULTS Sj14FABP gene was successfully expressed in the BmN cells and silkworm larvae infected with Bm-Sj14. The product was a 18 kDa fusion protein. The yield in BmN cells was about 100 micrograms/1 x 10(6) cells and 33 micrograms/ml cell supernatant. In silkworm larvae, the product yield was 4 mg/ml haemolymph as well as 4.6 mg/g silkworm tissue. The recombinant protein could be recognized by Western blotting and ELISA using the sera from mice immunized with SWAP. CONCLUSION Sj14FABP gene has been successfully expressed in BmNPV system and the product has high antigenicity.
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Yuan C, Beach KW, Smith LH, Hatsukami TS. Measurement of atherosclerotic carotid plaque size in vivo using high resolution magnetic resonance imaging. Circulation 1998; 98:2666-71. [PMID: 9851951 DOI: 10.1161/01.cir.98.24.2666] [Citation(s) in RCA: 218] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Current imaging modalities, such as contrast angiography, accurately determine the degree of luminal narrowing but provide no direct information on plaque size. Magnetic resonance imaging (MRI), however, has potential for noninvasively determining arterial wall area (WA). This study was conducted to determine the accuracy of in vivo MRI for measuring the cross-sectional maximum wall area (MaxWA) of atherosclerotic carotid arteries in a group of patients undergoing carotid endarterectomy. METHODS AND RESULTS Fourteen patients scheduled for carotid endarterectomy underwent preoperative carotid MRI using a custom-made phased-array coil. The plaques were excised en bloc and scanned using similar imaging parameters. MaxWA measurements from the ex vivo MRI were used as the reference standard and compared with MaxWA measurements from the corresponding in vivo MR study. Agreement between the in vivo and ex vivo measurement was analyzed using the Bland-Altman method. The paired in vivo and ex vivo MaxWA measurements strongly agreed: the mean difference (in vivo minus ex vivo) in MaxWA was 13.1+/-6.5 mm2 for T1-weighted (T1W) imaging (mean MaxWA in vivo=94.7 mm2, ex vivo=81.6 mm2) and 14.1+/-11.7 mm2 for proton density-weighted (PDW) imaging (mean MaxWA in vivo=93.4 mm2, ex vivo=79.3 mm2). Intraobserver and interobserver variability was small, with intraclass correlation coefficients ranging from 0.90 to 0.98. CONCLUSIONS MRI is highly accurate for in vivo measurement of artery WA in atherosclerotic carotid lesions. This imaging technique has potential application monitoring lesion size in studies examining plaque progression and/or regression.
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Yuan C, Wang J, Liang Z, Xin N. [Determination of sisomicin in body fluid by high performance liquid chromatography-indirect photometric detection method]. Se Pu 1998; 16:445-7. [PMID: 11498926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
A high performance liquid chromatography-indirect photometric detection (HPLC-IPD) method for determination of sisomicin sulfate in body fluid (serum, urine, saliva, cerebrospinal fluid and fluid oozed out from wound) was established. The conditions in this method were a mobile phase solution of methyl alcohol-acetonitrile-water (20:10:70) containing nicotinamide 0.5 mmol/L, sodium 1-heptanesulfonate 5 mmol/L and phosphoric acid 0.05 mol/L, a Spherisorb C18 column (4.6 mm x 250 mm) and an UV detector with sensitivity of 0.05 Aufs (0.1 Aufs for urine). The detection wavelength was fixed at 268 nm. The average recovery for sisomicin in serum was 96.92% +/- 4.63% and the coefficients of variation were 4.75% and 5.65% for within-day and day-to-day tests respectively. The detectable limit was 0.1 ng. The concentration of sisomicin in body fluid of 4 patients was determined.
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Eubank WB, Schmiedl UP, Yuan C, Black CD, Kellar KE, Ladd DL, Nelson JA. Black blood magnetic resonance angiography with Dy-DTPA polymer: effect on arterial intraluminal signal intensity, lumen diameter, and wall thickness. J Magn Reson Imaging 1998; 8:1051-9. [PMID: 9786141 DOI: 10.1002/jmri.1880080508] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Four rabbits in which atherosclerotic disease was induced by diet and balloon angioplasty underwent conventional angiography and MR angiography (MRA) using a black blood pulse sequence before and 10 minutes after the i.v. injection of a macromolecular contrast agent, NC 100283 (1.0 mmol/kg), a dysprosium diethylenetriaminepentaacetic acid hexamethylenediamine copolymer (Dy-DTPA polymer). Intraluminal signal intensity, apparent wall thickness, and lumen size measurements of the aorta and proximal common iliac arteries on precontrast MRA images were compared with postcontrast images. Aortic lumen diameter measurements on the precontrast and postcontrast MRA studies were compared with lumen diameters from conventional angiograms. Intraluminal signal intensity decreased on postcontrast MRA images compared with precontrast images, with an average loss of signal equal to 29% (P < .05). Apparent wall thickness decreased by 24% (P < .05). Lumen diameter and area were generally larger (average of 15% and 33%, respectively) on postcontrast MRA images than on precontrast images. Aortic lumen diameter measurements from postcontrast MRA agreed closely (95% confidence interval of the mean difference was -.2 to .3 mm), and precontrast MRA images tended to underestimate aortic lumen diameter (95% confidence interval of the mean difference was .3 to .8 mm) compared with conventional angiography. Postcontrast MRA with NC 100283, a macromolecular Dy-DTPA contrast agent, provides more accurate assessment of aortic lumen diameter than precontrast MRA, using conventional angiography as the standard reference.
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Yuan C, Chen H, Anderson RE, Kuwata O, Ebrey TG. The unique lipid composition of gecko (Gekko Gekko) photoreceptor outer segment membranes. Comp Biochem Physiol B Biochem Mol Biol 1998; 120:785-9. [PMID: 9854823 DOI: 10.1016/s0305-0491(98)10079-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study investigated the lipid and fatty acid composition of gecko photoreceptor outer segment membranes which contain the P521 cone-type pigment. The lipids of gecko photoreceptor outer segment membranes were first extracted and separated by thin layer chromatography (TLC) and then analyzed by gas chromatography (GC). Our results show that gecko photoreceptor outer segment membranes contain less phosphatidylethanolamine (PE) and more phosphatidylcholine (PC) and phosphatidylserine (PS) compared with those of bovine and frog. The content of the polyunsaturated fatty acid, docosahexaenoic acid (DHA), in PC and PS is also the highest yet reported (55 and 63%, respectively). These lipid differences may provide some insight into the specific lipid requirements of cone-type pigments.
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Pessa JE, Zadoo VP, Mutimer KL, Haffner C, Yuan C, DeWitt AI, Garza JR. Relative maxillary retrusion as a natural consequence of aging: combining skeletal and soft-tissue changes into an integrated model of midfacial aging. Plast Reconstr Surg 1998; 102:205-12. [PMID: 9655429 DOI: 10.1097/00006534-199807000-00034] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The contribution of maxillary retrusion to the formation of the nasolabial fold is evaluated in the present study. Clinical observation of patients from the craniofacial unit with concomitant maxillary retrusion revealed prominent signs of midfacial aging: specifically these individuals displayed a prominent nasolabial fold at an early age. This observation led to the hypothesis that relative maxillary retrusion occurs as a normal feature of the aging process. Retrusion of the lower facial skeleton below the soft tissue of the nasolabial fold causes the nasolabial fold to appear more prominent. To test this hypothesis, computed tomographic data were assembled retrospectively and included both males and females, young and old. The age range of the males (n = 14) was 18 to 24 years (young) and 43 to 57 years (old); the age range of the females (n = 14) was 15 to 30 years (young) and 43 to 57 years (old). All individuals had complete upper dentition and had no bony facial injury. Computed tomographic data were reconstructed into three-dimensional images, and a technique was developed to create a standardized lateral view which eliminated rotational variance. Analysis of anterior-posterior changes showed that there is a tendency for the lower maxillary skeleton at pyriform to become retrusive with age relative to the upper face in individuals with complete dentition. Findings were very significant for both males and females (p = 0.0001 and p = 0.002, respectively). In both groups, a slight increase in vertical maxillary dimension was noted, consistent with previous studies. It is suggested that relative maxillary retrusion is a factor in the development of the nasolabial fold. The skeletal features of normal midfacial aging can be combined with the soft-tissue features such as ptosis and atrophy into an integrated model of midfacial aging. A model such as this has significance regarding both the timing and choice of procedure used to restore the aging midface.
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Pamnani MB, Chen S, Haddy FJ, Yuan C, Mo Z. Role of digitalis-like substance in the hypertension of streptozotocin-induced diabetes and simulated weightlessness in rats. Clin Exp Hypertens 1998; 20:509-21. [PMID: 9682907 DOI: 10.3109/10641969809053229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have examined the role of plasma Na+-K+ pump inhibitor (SPI) in the hypertension of streptozotocin induced insulin dependent diabetes (IDDM) in reduced renal mass rats. The increase in blood pressure (BP) was associated with an increase in extracellular fluid volume (ECFV), and SPI and a decrease in myocardial Na+,K+ATPase (NKA) activity, suggesting that increased SPI, which inhibits cardiovascular muscle (CVM) cell NKA activity, may be involved in the mechanism of IDDM-hypertension. In a second study, using prolonged suspension resulted in a decrease in cardiac NKA activity, suggesting that cardiovascular deconditioning following space flight might in part result from insufficient SPI.
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Williams RM, Yuan C, Lee VJ, Chamberland S. Synthesis and antimicrobial evaluation of TAN-1057A/B analogs. J Antibiot (Tokyo) 1998; 51:189-201. [PMID: 9544941 DOI: 10.7164/antibiotics.51.189] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
TAN-1057A-D, dipeptides isolated from bacteria Flexibacter sp. PK-74 and PK-176, are new antibiotics with potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). We describe, in detail, the synthesis of several TAN-1057A/B analogs by a convergent route featuring a new method to construct the cyclic amidinourea functional group. The biological activity of these substances against methicillin-resistant Staphylococcus aureus (MRSA) is reported.
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Winn WB, Schmiedl UP, Reichenbach DD, Beach KW, Nghiem H, Dimas C, Daniel E, Maravilla KR, Yuan C. Detection and characterization of atherosclerotic fibrous caps with T2-weighted MR. AJNR Am J Neuroradiol 1998; 19:129-34. [PMID: 9432170 PMCID: PMC8337332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE We assessed the performance of T2-weighted MR imaging in detecting atherosclerotic fibrous caps and in depicting their integrity. METHODS Twenty atherosclerotic lesions removed by carotid endarterectomy were imaged on a 1.5-T system using T2-weighted spin-echo sequences. The MR images were reviewed independently by four blinded interpreters for fibrous caps and ruptures. The results obtained from the observers were then graded against histologic findings by using receiver-operating characteristic (ROC) curve analysis. RESULTS The area under the ROC curve for fibrous cap detection was 0.80, indicating that T2-weighted MR imaging was a good but not definitively diagnostic test for detecting ex vivo fibrous caps. The ROC curve for fibrous cap characterization yielded an area of 0.75, indicating that T2-weighted MR imaging was a fair but not highly diagnostic test for depicting fibrous cap integrity. A definite reading for detection of fibrous caps or rupture was fairly specific (90% and 98%, respectively) but not very sensitive (37% and 12%, respectively). CONCLUSIONS T2-weighted MR imaging of ex vivo atherosclerotic plaques aided in the detection and evaluation of fibrous caps. In both cases, MR imaging proved more useful for ruling out disease than for confirming its presence.
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von Ingersleben G, Schmiedl UP, Hatsukami TS, Nelson JA, Subramaniam DS, Ferguson MS, Yuan C. Characterization of atherosclerotic plaques at the carotid bifurcation: correlation of high-resolution MR imaging with histologic analysis--preliminary study. Radiographics 1997; 17:1417-23. [PMID: 9397455 DOI: 10.1148/radiographics.17.6.9397455] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The clinical symptoms and morbidity that result from carotid artery disease, the primary cause of stroke, are mainly due to plaque ulceration, thrombosis, intraplaque hemorrhage, and thinned fibrous caps. The contents of atherosclerotic plaques of the carotid artery can be determined with in vivo high-resolution magnetic resonance imaging with flow suppression. Eight patients scheduled to undergo endarterectomy and four healthy volunteers were imaged with a 1.5-T imager and custom-made carotid phased-array coils. T1-weighted spin-echo images and cardiac-gated proton-density--weighted fast spin-echo images were acquired. In vivo imaging findings as determined by three radiologists were correlated with ex vivo imaging and histologic findings. Among the eight plaque specimens, regions of hemorrhage, calcium, lipid deposits, and fibrous plaques were identified on T1- and proton-density-weighted images. Calcium and lipid deposits were detectable on both T1- and proton-density--weighted images. Hemorrhage and fibrous plaques were better demonstrated on proton-density--weighted images.
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228
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Sun H, Wang X, Huang R, Yuan C. [Determination of arbutin in the herbs of Vaccinium vitis-idaea L. by RP-HPLC]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1997; 22:555 inside back cover. [PMID: 11038950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Determination of arbutin in the herbs of Vaccinium vitis-idaea has been carried out by RP-HPLC, using Inertsil-ODS column (4.6 mm x 250 mm) and mobile phase of methanol and water (15:85), and detecting at 280 nm wavelength. The average content of arbutin is 4.44%, RSD = 2.93%; the recovery rate is 100.7%, RSD = 2.85%.
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229
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Yuan C, Petty C, O'Brien KD, Hatsukami TS, Eary JF, Brown BG. In vitro and in situ magnetic resonance imaging signal features of atherosclerotic plaque-associated lipids. Arterioscler Thromb Vasc Biol 1997; 17:1496-503. [PMID: 9301626 DOI: 10.1161/01.atv.17.8.1496] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The goal of this study was to evaluate magnetic resonance imaging (MRI) signal features of the different types of lipids found in human atherosclerotic plaques. A 1.5-T SIGNA scanner was used to acquire T1-, T2-, and proton density-weighted data at four different temperatures for individual lipids and lipid mixtures designed to replicate the proportions of lipids found in plaques. Individual lipids and lipid mixtures were scanned both in a test tube and after implantation in the media of normal porcine aortas. Each of the three broad classes of lipids (triglycerides, unesterified and esterified cholesterol, and phospholipids) had different and distinct MR signal patterns, which allowed discrimination of these classes of lipids in vitro. Further, lipid implantation studies demonstrated that these distinct MR signal patterns could be used to readily distinguish each lipid type from surrounding porcine aortic media. MR signals from lipid mixtures demonstrated marked regional heterogeneity, similar to the heterogeneous lipid distribution characteristic of human atherosclerotic plaques. In summary, MR signals from lipid mixtures that mimic plaque lipid proportions can be detected at body temperature, especially in those mixtures with an increased percentage of cholesteryl esters. These studies raise the possibility that with further advances in technology, MRI may become a useful tool for determining the lipid content and composition of human atherosclerotic plaques in vivo.
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230
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Wang D, Sun H, Han Y, Wang X, Yuan C. [Chemical constituents of the stems and leaves of Trigonella foenum-graecum L]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1997; 22:486-7, 512. [PMID: 11038916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Two compounds were isolated from the leaves and stems of Trigonella foenum-graecum, and on the basis of spectral analysis, their structures were elucidated as gamma-schizandrin and scopoletin. They were isolated from T. foenum-grecum for the first time.
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231
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Yang B, Wu Q, Yuan C. [Extra-anatomical bypass for subclavian artery occlusion]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1997; 35:481-3. [PMID: 10678070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
20 patients with subclavian artery occlusion were treated by extra-anatomical bypass from 1989 to 1996. There were 9 men and 11 women, aged from 20 to 63 years with a duration of 1 month to 18 years. The main causes of illness were Takayasu's arteritis and atherosclerosis. Symptoms of upper extremity ischemia were present in 17 patients and vertebrobasilar insufficiency in 11. Carotid-subclavian/axillary bypass and axilloaxillary bypass were performed on 17 and 3 patients respectively. There were no operative deaths. Relief of symptomes was achieved in all the patients except one who had reocclusion of bypass graft due to rather poor outflow vessel. We stressed the surgiacal technique of extra-anatomical bypass in the treatment of subclavian artery occlusion. With few postoperative complications and high patency rate, we consider extra-anatomical bypass a safe, simple, well-tolerated and durable procedure for the treatment of subclavian artery occlusive disease in high-risk patients.
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Wei Y, Lu Z, Yuan C, Gan Q. Molecular electronics: strategies and progress in China. IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE : THE QUARTERLY MAGAZINE OF THE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY 1997; 16:53-61. [PMID: 9241521 DOI: 10.1109/51.603649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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233
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Posse S, Dager SR, Richards TL, Yuan C, Ogg R, Artru AA, Müller-Gärtner HW, Hayes C. In vivo measurement of regional brain metabolic response to hyperventilation using magnetic resonance: proton echo planar spectroscopic imaging (PEPSI). Magn Reson Med 1997; 37:858-65. [PMID: 9178236 DOI: 10.1002/mrm.1910370609] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A new rapid spectroscopic imaging technique with improved sensitivity and lipid suppression, referred to as Proton Echo Planar Spectroscopic Imaging (PEPSI), has been developed to measure the 2-dimensional distribution of brain lactate increases during hyperventilation on a conventional clinical scanner equipped with a head surface coil phased array. PEPSI images (nominal voxel size: 1.125 cm3) in five healthy subjects from an axial section approximately 20 mm inferior to the intercommissural line were obtained during an 8.5-min baseline period of normocapnia and during the final 8.5 min of a 10-min period of capnometry-controlled hyperventilation (end-tidal PCO2 of 20 mmHg). The lactate/N-acetyl aspartate signal increased significantly from baseline during hyperventilation for the insular cortex, temporal cortex, and occipital regions of both the right and left hemisphere, but not in the basal ganglia. Regional or hemispheric right-to-left differences were not found. The study extends previous work using single-voxel MR spectroscopy to dynamically study hyperventilation effects on brain metabolism.
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234
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Kaneko E, Yuan C, Skinner MP, Raines EW, Ross R. Serial magnetic resonance imaging of experimental atherosclerosis allows visualization of lesion characteristics and lesion progression in vivo. Ann N Y Acad Sci 1997; 811:245-52; discussion 252-4. [PMID: 9186602 DOI: 10.1111/j.1749-6632.1997.tb52006.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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235
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Beach KW, Comess KA, Primozich JF, Yuan C, Powell K, Phillips DJ, Dunmire B, Plett M, Brown K, Paun M, Strandness DE. Ultrasonic color flow mapping: the visualization of four-dimensional cardiac and vascular flow phenomena using two dimensions and "real time". ULTRASOUND IN MEDICINE & BIOLOGY 1997; 23:347-363. [PMID: 9160903 DOI: 10.1016/s0301-5629(96)00215-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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236
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Wildy KS, Yuan C, Tsuruda JS, Ferguson MS, Wen N, Subramaniam DS, Strandness DE. Atherosclerosis of the carotid artery: evaluation by magnetic resonance angiography. J Magn Reson Imaging 1996; 6:726-32. [PMID: 8890010 DOI: 10.1002/jmri.1880060505] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Carotid artery atherosclerotic plaques (APs) can lead to brain ischemia, an event shown to correlate with both the degree of stenosis and the composition of the AP. Currently, accurate estimates of stenosis can be obtained by either x-ray angiography or three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA). Our purpose was to determine whether three-dimensional TOF MRA images could also provide information on plaque location, morphology, and composition. Seven pre-endarterectomy patients underwent three-dimensional TOF MRA. After endarterectomy, plaque histology was evaluated. Three-dimensional TOF MRA images contained sufficient soft tissue contrast to differentiate the plaques from the surrounding tissues in all cases. Estimation of plaque morphology had 80% correlation with histology. Finally, intraplaque hemorrhage and calcification were deplicted as regions of moderately high and very low intensity, respectively. These preliminary results suggest that three-dimensional TOF MRA may be useful in studying the development and progression of carotid atherosclerosis.
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Yuan C, Mei Z, Liu S, Yi L. PSK protects macrophages from lipoperoxide accumulation and foam cell formation caused by oxidatively modified low-density lipoprotein. Atherosclerosis 1996; 124:171-81. [PMID: 8830930 DOI: 10.1016/0021-9150(96)05835-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In previous works, it has been evidenced that lipoperoxidative injury to macrophages caused by oxidatively modified low-density lipoprotein (O-LDL) plays an important role in foam cell formation, and that PSK, a protein bound polysaccharide extracted from the class Basidiomycetes Coriolus Versicolor, can protect macrophages from lipoperoxidative injury induced by tert-butyl hydroperoxide (tbOOH). In this paper PSK protection of macrophages from lipoperoxide (LPO) accumulation and foam cell formation caused by O-LDL and its action mechanism were further studied. The LPO accumulation was determined by using ACAS 570. Dynamic assay of the LPO level in eight single cells after adding O-LDL or determination of the average LPO content in a lot of cells incubated in advance with O-LDL for 12 h, both indicated that O-LDL might induce LPO accumulation in macrophages and the effects of O-LDL could be prevented by PSK. O-LDL might cause the changes of morphological structure in macrophages and the transformation of macrophages into foam cells, and the effects could also be prevented by PSK. The determination of selenium-dependent glutathione peroxidase (SeGSHPx) activities and mRNA contents of macrophages and changes of SeGSHPx activity and mRNA content after incubation with tbOOH showed that PSK might increase the SeGSHPx activity of macrophage and the enhanced SeGSHPx activity may occur at the level of gene transcription.
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238
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Stump DR, Wiest M, Yuan C. Detecting a light gravitino at a linear collider to probe the SUSY-breaking scale. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1996; 54:1936-1943. [PMID: 10020873 DOI: 10.1103/physrevd.54.1936] [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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239
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Abstract
Morphological alterations of cardiac mitochondria have been observed in rats chronically treated with cocaine. Whether cocaine directly causes heart mitochondrial dysfunction remains unclear. The present study was undertaken to investigate the effect of cocaine on mitochondrial function in cultured myocardial cells. Cells were incubated with cocaine (10(-5)-10(-3) M) for 3-72 h, using either a repeated or single exposure protocol. Cocaine (10(-3) M) produced severe cytotoxicity after repeated exposure (24-72 h), as elevated by leakage of lactate dehydrogenase. Treatment of the cultures with a single exposure protocol (10(-5)-10(-3) M for 24 h or less) produced a very modest cytotoxic effect, as shown by a small increase in LDH leakage. However, cellular ATP levels showed a time-dependent decline in cultures treated with the single exposure protocol. Experiments using a digitized fluorescence imaging system revealed that cocaine (single exposure protocol) caused a dose- and time-dependent decrease in mitochondrial membrane potential, and the decline in membrane potential occurred prior to manifestation of cytotoxicity shown with the repeated exposure protocol. Cytosolic and mitochondrial calcium levels, as determined by fura-2, were not affected during treatment with cocaine. Our results suggest that cocaine may compromise cardiac mitochondrial function and may lead to cardiotoxicity.
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240
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Schmiedl UP, Yuan C, Nghiem HV, Winter TC, Freeny PC. MR angiography of the peripheral vasculature. Semin Ultrasound CT MR 1996; 17:404-11. [PMID: 8858778 DOI: 10.1016/s0887-2171(96)90026-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
MR angiography (MRA) for the evaluation of peripheral arterial occlusive disease is a rapidly evolving technique. Recent prospective clinical trials have indicated that MRA may play an important role in the evaluation of patients with peripheral arterial disease. This article discusses the pertinent technical aspects and limitations of peripheral MRA as well as some of the clinical data available.
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241
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Yuan C, Wu Q, Wang S. [Surgical treatment of juxta-renal abdominal aortic occlusion: report of 27 cases]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1996; 34:388-90. [PMID: 9590785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Juxta-renal abdominal aortic occlusion is a relatively rare disease. We have treated 27 patients (25 males and 2 females) since 1984. Operations were performed on 25 patients, of whom 4 died and 84% improved. The main etiology was aorto-iliac stenosis or occlusion due to atherosclerosis and Takayasu's arteritis. Diagnostic basis included ischemia of lower limbs, pulselessness of abdominal aorta and both femoral arteries, sexual dysfunction, and positive result of angiography. Effective control of aorta below the left renal vein, aortotomy and retrograde endarterectomy were the main operative procedures. Axillo-bifemoral arterial bypass is recommended for patients associated with multiple diseases. The operative result is determined by associated diseases and the condition of run-off vessel. Associated diseases directly affect the mortality rate.
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242
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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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243
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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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244
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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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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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