101
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Lu J, Yu X, Chen G, Cheng D. Characterizing the Synchronizability of Small-World Dynamical Networks. ACTA ACUST UNITED AC 2004. [DOI: 10.1109/tcsi.2004.823672] [Citation(s) in RCA: 378] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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102
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Cheng D. Emergency Medicine Advertisement Paradox. Acad Emerg Med 2003. [DOI: 10.1197/s1069-6563(03)00548-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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103
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Davies P, Cheng D, Fox A, Lee L. Wafting does work. Arch Dis Child Fetal Neonatal Ed 2003; 88:F446. [PMID: 12937063 PMCID: PMC1721601 DOI: 10.1136/fn.88.5.f446-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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104
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Cheng D. Female Chairs and Female Faculty. Acad Emerg Med 2003. [DOI: 10.1197/aemj.10.5.459-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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105
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Waters WR, Rahner TE, Palmer MV, Cheng D, Nonnecke BJ, Whipple DL. Expression of L-Selectin (CD62L), CD44, and CD25 on activated bovine T cells. Infect Immun 2003; 71:317-26. [PMID: 12496181 PMCID: PMC143305 DOI: 10.1128/iai.71.1.317-326.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium bovis infection of cattle represents a natural host-pathogen interaction and, in addition to its economic and zoonotic impact, represents a model for human tuberculosis. Extravasation and trafficking of activated lymphocytes to inflammatory sites is modulated by differential expression of multiple surface adhesion molecules. However, effects of M. bovis infection on adhesion molecule expression have not been characterized. To determine these changes, peripheral blood mononuclear cells from M. bovis-infected cattle were stimulated with M. bovis purified protein derivative (PPD) or pokeweed mitogen (PWM) and evaluated concurrently for proliferation and activation marker expression. Stimulation with PPD or PWM increased CD25 and CD44 mean fluorescence intensity (MFI) and decreased CD62L MFI on CD4(+) cells from infected animals. CD62L MFI on PPD- and PWM-stimulated gammadelta T-cell receptor-positive (TCR(+)) and CD8(+) cells was also reduced compared to that of nonstimulated gammadelta TCR(+) and CD8(+) cells. Using a flow cytometry-based proliferation assay, it was determined that proliferating cells, regardless of lymphocyte subset, exhibited increased expression of CD25 and CD44 and decreased expression of CD62L compared to cells that had not proliferated. In contrast to proliferation, activation-induced apoptosis of CD4(+) cells resulted in a significant down regulation of CD44 expression. Lymphocytes obtained from lungs of M. bovis-infected cattle also had reduced expression of CD44 compared to lymphocytes from lungs of noninfected cattle. These alterations in surface molecule expression upon activation likely impact trafficking to sites of inflammation and the functional capacity of these cells within tuberculous granulomas.
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106
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Cheng D. An investigation on rural birthrates in Hubei Province. CHINESE SOCIOLOGY AND ANTHROPOLOGY 2002; 16:107-16. [PMID: 12314767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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107
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Addrizzo-Harris DJ, Harkin TJ, Tchou-Wong KM, McGuinness G, Goldring R, Cheng D, Rom DWN. Mechanisms of colchicine effect in the treatment of asbestosis and idiopathic pulmonary fibrosis. Lung 2002; 180:61-72. [PMID: 12172901 DOI: 10.1007/s004080000083] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2002] [Indexed: 10/27/2022]
Abstract
The objective of this study was to evaluate the mechanisms of colchicine action in pulmonary fibrosis. The study included 10 patients with pulmonary fibrosis (idiopathic pulmonary fibrosis 5, asbestosis 4, and scleroderma 1) who had been admitted to Bellevue Hospital Center, a tertiary care public hospital in New York City. We administered colchicine 0.6 mg orally for 12 weeks to patients with pulmonary fibrosis. Symptoms, high resolution CT scans, pulmonary function tests, and bronchoalveolar lavage parameters were compared prior to and after treatment. Results showed declines in dyspnea index, selective improvement in several CT scans, but no statistically significant change in BAL cells, cytokines, fibronectin, or hydroxyproline. However, there was a decline in hydroxyproline in the BAL fluid in 8/10 patients. We concluded that colchicine has a mild antifibrotic effect which may be in inhibiting collagen formation since there was no effect on the inflammation that accompanies fibrosis.
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108
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Hjelm NM, Lee JCK, Cheng D, Chui C. Wiring a medical school and teaching hospital for telemedicine. Int J Med Inform 2002; 65:161-6. [PMID: 12052428 DOI: 10.1016/s1386-5056(02)00010-2] [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: 10/27/2022]
Abstract
The planning and installation of a telemedicine system for communication within a teaching hospital and its academic and hospital units with a capacity for accommodation of up to 400 video-stations is described. The system is intended for improving the communication between patients and health professionals, and between the health professionals themselves. It also provides the basis for improving pre-graduate teaching, especially problem-based learning, and all aspects of postgraduate teaching.
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109
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Hjelm N, Lee J, Cheng D, Chui C. Erratum to “Wiring a medical school and teaching hospital for telemedicine”. Int J Med Inform 2002. [DOI: 10.1016/s1386-5056(02)00009-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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110
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Cheng D. 2000 Subway World Series Influence on Emergency Department Gender Census. Acad Emerg Med 2002. [DOI: 10.1197/aemj.9.5.388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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111
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Cheng D, Khan MA, Houser RP. Coordination polymers composed of copper(II), trimesic acid, and imidazole: 3D architecture stabilized by hydrogen bonding. Inorg Chem 2001; 40:6858-9. [PMID: 11754261 DOI: 10.1021/ic015609v] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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112
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Cheng D, Xiao X, Chen W. [The expression of tyrosine-kinase receptor flk-1 and hypoxic pulmonary vascular remodeling in the lung of rats exposed to hypoxia]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 2001; 32:489-91. [PMID: 12528527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To assess the role of tyrosine-kinase receptor flk-1 in the development of hypoxic pulmonary vascular remodeling. METHODS We divided 20 male Wistar rats into two groups(control vs hypoxia) and exposed them to normoxic condition and isobaric hypoxia for 3 weeks respectively. The pulmonary artery pressure was measured by right cardiac catheterization. The expression of flk-1 in lung tissues was measured by immunohistochemical staining. Histologic sections of the lungs were examined by a computerized image analyser. RESULTS In hypoxic rats, the pulmonary artery pressure was significantly raised to a higher level, P < 0.01; the cell number of vascular wall was significantly increased. The results also demonstrated that chronic hypoxia brought about the significant increment in thickness of wall with narrowing of lumen of pulmonary arterioles, and the increment in the percent of vascular wall thickness/vascular external diameter (WT%) and the percent of vascular wall area/total vascular area (WA%), P < 0.01. The positive staining of flk-1 in the wall of pulmonary arteriole of rats treated with hypoxia was significantly stronger than that of normal rats, P < 0.01. Positive correlations were seen between the increment of expression of flk-1 with WT% and WA% (r = 0.714, 0.738, P < 0.01). CONCLUSION Chronic hypoxia can induce an increasing expression of flk-1, and the flk-1 may play an important role in the pathogenesis of hypoxic pulmonary vascular remodeling.
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113
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Cheng D, Meegalla RL, He B, Cromley DA, Billheimer JT, Young PR. Human acyl-CoA:diacylglycerol acyltransferase is a tetrameric protein. Biochem J 2001; 359:707-14. [PMID: 11672446 PMCID: PMC1222193 DOI: 10.1042/0264-6021:3590707] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT) is an integral membrane enzyme that catalyses the last step of triacylglycerol synthesis from diacylglycerol and acyl-CoA. Here we provide experimental evidence that DGAT is a homotetramer. Although the predicted molecular mass of human DGAT protein is 55 kDa, CHAPS-solubilized recombinant human DGAT was eluted in fractions over 150 kDa on gel-filtration chromatography. Cross-linking of recombinant DGAT in membranes with disuccinimidyl suberate yielded bands corresponding to the dimer (108 kDa) and the tetramer (214 kDa) in SDS/PAGE. Finally, when two differently epitope-tagged forms of DGAT were co-transfected into mammalian cells, they could be co-immunoprecipitated. From a human adipose tissue cDNA library we cloned a cDNA encoding a novel splice variant of DGAT (designated DGATsv) that contained a 77 nt insert of unspliced intron with an in-frame stop codon. This resulted in a truncated form of DGAT that terminated at Arg-387, deleting 101 residues from the C-terminus containing the putative active site. DGATsv was enzymically inactive when transfected in HEK-293E cells but was still able to form dimer and tetramer on cross-linking, indicating that the ability to form tetramers resides in the N-terminal region. When co-expressed in HEK-293E cells, DGATsv did not inhibit the activity of full-length DGAT, suggesting that the subunits of DGAT catalyse triacylglycerol synthesis independently.
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114
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Huang G, Qian G, Cheng D. [The effect of monocarboxylate transporter gene on the regulation of pHi and growth character in cancer cells]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 2001; 24:666-70. [PMID: 16136905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVE To study the influence of the first subtype of monocarboxylate transporter (MCT1) gene on pHi regulation, lactate transport and cell growth in tumor cells. METHODS (1) With RT-PCR technique, MCT1 cDNA fragment was cloned from human lung cancer cells A549, and the cloned fragment MCT1 was reversely inserted into the vector pLXSN to acquire antisense expression recombinant vector pLXSN-MCT1. (2) pLXSN, pLXSN-MCT1 were respectively introduced into the A549 cells by electroporation. The transfected A549 cell resistant to G418 drug was selected as positive clones and proved by PCR. The changes of intracellular pH and lactate in the transfected A549 cells were detected by spectrophotometric method. Cell growth was studied by cell growth curve. RESULTS (1) The cloned fragment was in the length of 640 bp and successfully bound to pLXSN. It was also proved to be the objective one by DNA sequencing. (2) Intracellular pH and lactate were remarkably decreased in the cells transfected pLXSN-MCT1, comparing to A549 cells without transfection (P < 0.001). The growth of A549 cells transfected pLXSN-MCT1 was also inhibited remarkably. CONCLUSION MCT1 gene could play an important role in pHi regulation, lactate transport and cell growth in tumor cells.
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Zhang Z, Sobel RA, Cheng D, Steinberg GK, Yenari MA. Mild hypothermia increases Bcl-2 protein expression following global cerebral ischemia. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 95:75-85. [PMID: 11687278 DOI: 10.1016/s0169-328x(01)00247-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mild hypothermia protects the brain against experimental ischemia, but the reasons are not well known. We examined whether the protective effects of mild hypothermia could be correlated with alterations in expression of Bcl-2, an anti-apoptotic protein in a rat model of transient global ischemia. Following 10 min of forebrain ischemia, hippocampal neurons were examined 72 h later for survival, expression of Bcl-2 family proteins and apoptosis. Intraischemic mild hypothermia was applied for 3 h (33 degrees C, isch-33) or normal body temperature was maintained (37 degrees C, isch-37). Survival of CA1 neurons was significantly improved in the isch-33 group compared to the isch-37 group (90 vs. 53% survival; P<0.01). The proportion of Bcl-2-positive cells among surviving CA1 neurons in the isch-33 group was increased compared to that of sham and isch-37 groups (P<0.01). Bax expression in CA1 was no different between sham and isch-33 groups, but was significantly decreased in isch-37 (P<0.05). TUNEL staining was positive in many isch-37 CA1 neurons, but absent in isch-33. Utilizing electron microscopy, more cells meeting criteria for apoptosis were observed in the isch-37 than isch-33. These data suggest that mild hypothermia attenuates apoptotic death, and that this protection may be related to increases in Bcl-2.
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116
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Cheng D, Tellkamp VL, Lavernia CJ, Lavernia EJ. Corrosion properties of nanocrystalline Co-Cr coatings. Ann Biomed Eng 2001; 29:803-9. [PMID: 11599588 DOI: 10.1114/1.1397790] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nanocrystalline and conventional Co-Cr (ASTM F75) coatings were prepared by plasma spraying for possible orthopedic implant applications. Scanning electron microscopy and transmission electron microscopy were used to study the macrostructure and microstructure of the resultant sprayed coatings. The corrosion resistance was characterized by an in vitro potentiodynamic anodic polarization technique in a pseudophysiological solution. The nanocrystalline coating has higher porosity, lower corrosion current density, and less localized damage than that of the conventional one, demonstrating better application potential for orthopedic implants. A change in the atomic compositional difference between the grain interior and the grain boundary, the presence of residual strain in the grain interiors, and a change in the repassivation kinetics are discussed as possible explanations for the enhanced corrosion behavior observed.
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Li L, Liu J, Cheng D. Aerodynamic adsorption of permeable chemical protective suit. AIHAJ : A JOURNAL FOR THE SCIENCE OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH AND SAFETY 2001; 62:559-62. [PMID: 11669381 DOI: 10.1080/15298660108984654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A new laboratory apparatus and method were developed to test the protective ability of a permeable chemical protective suit (PCPS). The key features of this method are using a wind tunnel system and an aerodynamic model that could incorporate the complicated flow pattern around the protective clothing. This method illustrates the process of the PCPS system performance and can provide a system assessment through bench-scale experiments. A new aerodynamic adsorption equation for PCPS breakthrough curve calculation based on an aerodynamic model has been suggested, and the calculated breakthrough curves of benzene vapor on PCPS conform to the experiment curves.
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118
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Raju B, Tung CF, Cheng D, Yousefzadeh N, Condos R, Rom WN, Tse DB. In situ activation of helper T cells in the lung. Infect Immun 2001; 69:4790-8. [PMID: 11447152 PMCID: PMC98566 DOI: 10.1128/iai.69.8.4790-4798.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2000] [Accepted: 05/10/2001] [Indexed: 11/20/2022] Open
Abstract
To better understand the lung and systemic responses of helper T cells mediating memory immunity to Mycobacterium tuberculosis, we used three- and four-color flow cytometry to study the surface phenotype of CD4(+) lymphocytes. Bronchoalveolar lavage (BAL) fluid and peripheral blood (PB) samples were obtained from a total of 25 subjects, including 10 tuberculosis (TB)-infected subjects, 8 purified-protein-derivative-negative subjects, and 7 purified-protein-derivative-positive subjects. In marked contrast to CD4(+) lymphocytes from PB (9% +/- 5% expressing CD45RA and CD29), the majority (55% +/- 16%) of CD4(+) lymphocytes in BAL (ALs) simultaneously expressed CD45RA, a naïve T-cell marker, and CD29, members of the very late activation family. Further evaluation revealed that CD4(+) ALs expressed both CD45RA and CD45RO, a memory T-cell marker. In addition, the proportion of CD4(+) lymphocytes expressing CD69, an early activation marker, was drastically increased in BAL fluid (83% +/- 9%) compared to PB (1% +/- 1%), whereas no significant difference was seen in the expression of CD25, the low-affinity interleukin 2 receptor (34% +/- 15% versus 40% +/- 16%). More importantly, we identified a minor population of CD69(bright) CD25(bright) CD4(+) lymphocytes in BAL (10% +/- 6%) that were consistently absent from PB (1% +/- 1%). Thus, CD4(+) lymphocytes in the lung paradoxically coexpress surface molecules characteristic of naïve and memory helper T cells as well as surface molecules commonly associated with early and late stages of activation. No difference was observed for ALs obtained from TB-infected and uninfected lung segments in this regard. It remains to be determined if these surface molecules are induced by the alveolar environment or if CD4(+) lymphocytes coexpressing this unusual combination of surface molecules are selectively recruited from the circulation. Our data suggest that ex vivo experiments on helper T-cell subsets that display distinctive phenotypes may be pivotal to studies on the human immune response to potential TB vaccines.
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Krakow B, Hollifield M, Johnston L, Koss M, Schrader R, Warner TD, Tandberg D, Lauriello J, McBride L, Cutchen L, Cheng D, Emmons S, Germain A, Melendrez D, Sandoval D, Prince H. Imagery rehearsal therapy for chronic nightmares in sexual assault survivors with posttraumatic stress disorder: a randomized controlled trial. JAMA 2001; 286:537-45. [PMID: 11476655 DOI: 10.1001/jama.286.5.537] [Citation(s) in RCA: 302] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Chronic nightmares occur frequently in patients with posttraumatic stress disorder (PTSD) but are not usually a primary target of treatment. OBJECTIVE To determine if treating chronic nightmares with imagery rehearsal therapy (IRT) reduces the frequency of disturbing dreams, improves sleep quality, and decreases PTSD symptom severity. DESIGN, SETTING, AND PARTICIPANTS Randomized controlled trial conducted from 1995 to 1999 among 168 women in New Mexico; 95% had moderate-to-severe PTSD, 97% had experienced rape or other sexual assault, 77% reported life-threatening sexual assault, and 58% reported repeated exposure to sexual abuse in childhood or adolescence. INTERVENTION Participants were randomized to receive treatment (n = 88) or to the wait-list control group (n = 80). The treatment group received IRT in 3 sessions; controls received no additional intervention, but continued any ongoing treatment. MAIN OUTCOME MEASURES Scores on the Nightmare Frequency Questionnaire (NFQ), Pittsburgh Sleep Quality Index (PSQI), PTSD Symptom Scale (PSS), and Clinician-Administered PTSD Scale (CAPS) at 3- and 6-month follow-up. RESULTS A total of 114 participants completed follow-up at 3 and/or 6 months. Comparing baseline to follow-up (n = 97-114), treatment significantly reduced nights per week with nightmares (Cohen d = 1.24; P<.001) and number of nightmares per week (Cohen d = 0.85; P<.001) on the NFQ and improved sleep (on the PSQI, Cohen d = 0.67; P<.001) and PTSD symptoms (on the PSS, Cohen d = 1.00; P<.001 and on the CAPS, Cohen d = 1.53; P<.001). Control participants showed small, nonsignificant improvements for the same measures (mean Cohen d = 0.21). In a 3-point analysis (n = 66-77), improvements occurred in the treatment group at 3-month follow-up (treatment vs control group, Cohen d = 1.15 vs 0.07 for nights per week with nightmares; 0.95 vs -0.06 for nightmares per week; 0.77 vs 0.31 on the PSQI, and 1.06 vs 0.31 on the PSS) and were sustained without further intervention or contact between 3 and 6 months. An intent-to-treat analysis (n = 168) confirmed significant differences between treatment and control groups for nightmares, sleep, and PTSD (all P<.02) with moderate effect sizes for treatment (mean Cohen d = 0.60) and small effect sizes for controls (mean Cohen d = 0.14). Posttraumatic stress symptoms decreased by at least 1 level of clinical severity in 65% of the treatment group compared with symptoms worsening or not changing in 69% of controls (chi(2)(1) = 12.80; P<.001). CONCLUSIONS Imagery rehearsal therapy is a brief, well-tolerated treatment that appears to decrease chronic nightmares, improve sleep quality, and decrease PTSD symptom severity.
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Lee JE, Yenari MA, Sun GH, Xu L, Emond MR, Cheng D, Steinberg GK, Giffard RG. Differential neuroprotection from human heat shock protein 70 overexpression in in vitro and in vivo models of ischemia and ischemia-like conditions. Exp Neurol 2001; 170:129-39. [PMID: 11421590 DOI: 10.1006/exnr.2000.7614] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously showed that overexpressing the 70-kDa inducible heat shock protein in primary astrocyte cultures and in a rodent stroke model using viral vectors resulted in protection from ischemia and ischemia-like injury. However, viral transfection could potentially provoke a stress response itself; therefore, we examined whether transgenic mice constitutively expressing human heat shock protein 70 were protected from ischemic insults. Astrocyte cultures from brains of heat shock protein 70 transgenic mice were resistant to hydrogen peroxide injury in a dose-dependent fashion, but were less resistant to hypoglycemia and oxygen-glucose deprivation. Because hydrogen peroxide exposure and glucose deprivation are partially dependent on glutathione levels, we determined whether heat shock protein 70 transgenic cultures had altered glutathione levels under normal growth conditions. However, there was no significant difference in glutathione levels between heat shock protein 70 transgenic and wildtype astrocytes. Hippocampal, but not cortical neuron cultures from these same transgenic mice were also protected against oxygen-glucose deprivation and glutamate toxicity. In an in vivo model of permanent focal cerebral ischemia, there was no significant difference in infarct size assessed 24 h postinsult. These results suggest that heat shock protein 70 protects against some but not all kinds of central nervous system injury. The protective effects may be related to the nature and severity of the insults, as well as subpopulations of brain cells and dose-dependent effects of HSP70 overexpression.
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121
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Cheng D, Woo GC. The effect of conventional CR39 and Fresnel prisms on high and low contrast acuity. Ophthalmic Physiol Opt 2001; 21:312-6. [PMID: 11430625 DOI: 10.1046/j.1475-1313.2001.00570.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of conventional CR39 and Fresnel prisms on high and low contrast letter acuity was studied. Visual acuity of the fully corrected better eyes of 15 subjects was measured with the high (90%) and low (10%) contrast logMAR letter charts, while they wore prisms of varying power. The results showed that when the power of the conventional CR39 prism and the Fresnel prism reached 10 prism dioptres and 5 prism dioptres, respectively, significant reduction (1 tail t-test, p < 0.05) of the high and low contrast acuity occurred. The Fresnel prism caused a significantly greater acuity reduction than the conventional CR39 prism for powers ranging from 5 to 30 prism dioptres for both contrasts. The rate of acuity reduction with increasing prism power was greater with the low contrast targets than with the high contrast targets for both prisms. In addition, the rate of acuity reduction with increasing prism power was greater with the Fresnel prism than with the conventional CR39 prism for both contrasts. The conventional CR39 prism reduced acuity by a ratio of about 0.8-0.9 of that of the Fresnel prism for powers ranging from 5 to 20 prism dioptres and by about 0.7 for 30 prism dioptres. These ratios applied for both high and low contrast acuity, and therefore were independent of the level of contrast used.
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Cheng D, Kreethadumrongdat T, Cohen T. Allylic lithium oxyanionic directed and facilitated simmons-smith cyclopropanation: stereoselective synthesis of (+/-)-cis-sabinene hydrate and a novel ring expansion. Org Lett 2001; 3:2121-3. [PMID: 11418064 DOI: 10.1021/ol016086y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The lithium salts of acid-sensitive allyl alcohols, which themselves decompose during Simmons-Smith cyclopropanation, undergo smooth cyclopropanation in the usual stereocontrolled manner. This concept is applied to the most efficient synthesis of (+/-)-cis-sabinene hydrate and to the cyclopropanation of the anion of a nonisolable allyl alcohol resulting upon workup in a ring-expanded enone. The cyclopropanations are also faster for the lithium salts than for the allyl alcohols themselves.
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Grigoriev VA, Cheng D, Hill CL, Weinstock IA. Role of alkali metal cation size in the energy and rate of electron transfer to solvent-separated 1:1 [(M+)(acceptor)] (M+ = Li+, Na+, K+) ion pairs. J Am Chem Soc 2001; 123:5292-307. [PMID: 11457392 DOI: 10.1021/ja010074q] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of cation size on the rate and energy of electron transfer to [(M(+))(acceptor)] ion pairs is addressed by assigning key physicochemical properties (reactivity, relative energy, structure, and size) to an isoelectronic series of well-defined M(+)-acceptor pairs, M(+) = Li(+), Na(+), K(+). A 1e(-) acceptor anion, alpha-SiV(V)W(11)O(40)(5-) (1, a polyoxometalate of the Keggin structural class), was used in the 2e(-) oxidation of an organic electron donor, 3,3',5,5'-tetra-tert-butylbiphenyl-4,4'-diol (BPH(2)), to 3,3',5,5'-tetra-tert-butyldiphenoquinone (DPQ) in acetate-buffered 2:3 (v/v) H(2)O/t-BuOH at 60 degrees C (2 equiv of 1 are reduced by 1e(-) each to 1(red), alpha-SiV(IV)W(11)O(40)(6-)). Before an attempt was made to address the role of cation size, the mechanism and conditions necessary for kinetically well behaved electron transfer from BPH(2) to 1 were rigorously established by using GC-MS, (1)H, (7)Li, and (51)V NMR, and UV-vis spectroscopy. At constant [Li(+)] and [H(+)], the reaction rate is first order in [BPH(2)] and in [1] and zeroth order in [1(red)] and in [acetate] (base) and is independent of ionic strength, mu. The dependence of the reaction rate on [H(+)] is a function of the constant, K(a)1, for acid dissociation of BPH(2) to BPH(-) and H(+). Temperature dependence data provided activation parameters of DeltaH = 8.5 +/- 1.4 kcal mol(-1) and DeltaS = -39 +/- 5 cal mol(-1) K(-1). No evidence of preassociation between BPH(2) and 1 was observed by combined (1)H and (51)V NMR studies, while pH (pD)-dependent deuterium kinetic isotope data indicated that the O-H bond in BPH(2) remains intact during rate-limiting electron transfer from BPH(2) and 1. The formation of 1:1 ion pairs [(M(+))(SiVW(11)O(40)(5-))](4-) (M(+)1, M(+) = Li(+), Na(+), K(+)) was demonstrated, and the thermodynamic constants, K(M)(1), and rate constants, k(M)(1), associated with the formation and reactivity of each M(+)1 ion pair with BPH(2) were calculated by simultaneous nonlinear fitting of kinetic data (obtained by using all three cations) to an equation describing the rectangular hyperbolic functional dependence of k(obs) values on [M(+)]. Constants, K(M)(1)red, associated with the formation of 1:1 ion pairs between M(+) and 1(red) were obtained by using K(M)(1) values (from k(obs) data) to simultaneously fit reduction potential (E(1/2)) values (from cyclic voltammetry) of solutions of 1 containing varying concentrations of all three cations to a Nernstian equation describing the dependence of E(1/2) values on the ratio of thermodynamic constants K(M)(1) and K(M)(1)red. Formation constants, K(M)(1), and K(M)(1)red, and rate constants, k(M)(1), all increase with the size of M(+) in the order K(Li)(1) = 21 < K(Na)(1) = 54 < K(K)(1) = 65 M(-1), K(Li)(1)red = 130 < K(Na)(1)red = 570 < K(K)(1)red = 2000 M(-1), and k(Li)(1) = 0.065 < k(Na)(1) = 0.137 < k(K)(1) = 0.225 M(-1) s(-1). Changes in the chemical shifts of (7)Li NMR signals as functions of [Li(5)1] and [Li(6)1(red)] were used to establish that the complexes M(+)1 and M(+)1(red) exist as solvent-separated ion pairs. Finally, correlation between cation size and the rate and energy of electron transfer was established by consideration of K(M)(1), k(M)(1), and K(M)(1)red values along with the relative sizes of the three M(+)1 pairs (effective hydrodynamic radii, r(eff), obtained by single-potential step chronoamperometry). As M(+) increases in size, association constants, K(M)(1), become larger as smaller, more intimate solvent-separated ion pairs, M(+)1, possessing larger electron affinities (q/r), and associated with larger k(M)(1)() values, are formed. Moreover, as M(+)1 pairs are reduced to M(+)1(red) during electron transfer in the activated complexes, [BPH(2), M(+)1], contributions of ion pairing energy (proportional to -RT ln(K(M)(1)red/K(M)(1)) to the standard free energy change associated with electron transfer, DeltaG degrees (et), increase with cation size: -RT ln(K(M)(1)red/K(M)(1)) (in kcal mol(-1)) = -1.2 for Li(+), -1.5 for Na(+), and -2.3 for K(+).
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Cheng D, Yi X, Chen W. [Cardio-pulmonary pathology of sudden death in asthma]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 2001; 24:295-7. [PMID: 11802980] [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 elucidate the pathological characteristics of the heart and lung in asthmatics with sudden death. METHOD A detail analysis of pathological data was performed on 14 patients with sudden death in asthma. RESULTS There was no apparent gender difference among 14 patients. 9 patients were younger than 30 years old. Pathological examination showed that bronchial infiltration of eosinophils in 14 patient (100%), thickened basement membrane of the bronchial mucosa in 12 patients (85.7%), proliferation of smooth muscle cells in 11 patients (78.6%), proliferative mucous gland in 9 patients (64.3%), mucous plug in bronchiole in 8 patients (57.1%), and cicatvization of left ventricle in 10 patients (71.4%). CONCLUSION Severe nonspecific airway inflammation is demonstrated in asthmatic patients with sudden death. Lesions of the left ventricle and mucous plug in bronchiole may contribute to the main cause leading sudden death.
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Howie MB, Cheng D, Newman MF, Pierce ET, Hogue C, Hillel Z, Bowdle TA, Bukenya D. A randomized double-blinded multicenter comparison of remifentanil versus fentanyl when combined with isoflurane/propofol for early extubation in coronary artery bypass graft surgery. Anesth Analg 2001; 92:1084-93. [PMID: 11323327 DOI: 10.1097/00000539-200105000-00003] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED We compared a fentanyl/isoflurane/propofol regimen with a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in a prospective, randomized, double-blinded study on patients undergoing elective coronary artery bypass graft surgery. Anesthesia was induced with a 1-min infusion of 0.5 mg/kg propofol followed by 10-mg boluses of propofol every 30 s until loss of consciousness. After 0.2 mg/kg cisatracurium, a blinded continuous infusion of remifentanil at 1 microg. kg(-1). min(-1) or the equivalent volume rate of normal saline was then started. In addition, a blinded bolus syringe of 1 microg/kg remifentanil or 10 microg/kg fentanyl, respectively, was given over 3 min. Blinded remifentanil, 1 microg. kg(-1). min(-1) (or the equivalent volume rate of normal saline), together with 0.5% isoflurane, were used to maintain anesthesia. Significantly more patients (P < 0.01) in the fentanyl regimen experienced hypertension during skin incision and maximum sternal spread compared with patients in the remifentanil regimen. There were no differences between the groups in time until extubation, discharge from the surgical intensive care unit, ST segment and other electrocardiogram changes, catecholamine levels, or cardiac enzymes. The remifentanil-based anesthetic (consisting of a bolus followed by a continuous infusion) resulted in significantly less response to surgical stimulation and less need for anesthetic interventions compared with the fentanyl regimen (consisting of an initial bolus, and followed by subsequent boluses only to treat hemodynamic responses) with both drug regimens allowing early extubation. IMPLICATIONS Both fentanyl and the newer opioid remifentanil, when each is combined with isoflurane and propofol, allowed for fast-track cardiac anesthesia. The remifentanil regimen used in this study resulted in significantly less hemodynamic response to surgical stimulation.
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