151
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McSharry PE, He T, Smith LA, Tarassenko L. Linear and non-linear methods for automatic seizure detection in scalp electro-encephalogram recordings. Med Biol Eng Comput 2002; 40:447-61. [PMID: 12227632 DOI: 10.1007/bf02345078] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The electro-encephalogram is a time-varying signal that measures electrical activity in the brain. A conceptually intuitive non-linear technique, multi-dimensional probability evolution (MDPE), is introduced. It is based on the time evolution of the probability density function within a multi-dimensional state space. A synthetic recording is employed to illustrate why MDPE is capable of detecting changes in the underlying dynamics that are invisible to linear statistics. If a non-linear statistic cannot outperform a simple linear statistic such as variance, then there is no reason to advocate its use. Both variance and MDPE were able to detect the seizure in each of the ten scalp EEG recordings investigated. Although MDPE produced fewer false positives, there is no firm evidence to suggest that MDPE, or any other non-linear statistic considered, outperforms variance-based methods at identifying seizures.
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Affiliation(s)
- P E McSharry
- Department of Engineering Science, University of Oxford, UK.
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152
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Zhang F, Liu J, Huang H, Du B, He T. Branched crystal morphology of linear polyethylene crystallized in a two-dimensional diffusion-controlled growth field. Eur Phys J E Soft Matter 2002; 8:289-297. [PMID: 15010950 DOI: 10.1140/epje/i2002-10015-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The branched crystal morphology of linear polyethylene formed at various temperatures from thin films has been studied by atomic-force microscopy (AFM), transmission electron microscopy (TEM), electron diffraction (ED) pattern and polymer decoration technique. Two types of branched patterns, i.e. dendrite and seaweed patterns, have been visualized. The fractal dimension d(f) = 1.65 of both dendrite and some of seaweed patterns was obtained by using the box-counting method, although most of the seaweed patterns are compact. Selected-area ED patterns indicate that the fold stems tilt about 34.5( degrees ) around the b-axis and polymer decoration patterns show that the chain folding direction and regularity in two (200) regions are quite different from each other. Because of chain tilting, branched crystals show three striking features: 1) the lamella-like branches show two (200) regions with different thickness; 2) the crystals usually bend towards the thin region; 3) the thick region grows faster by developing branches, thus branches usually occur outside the thick region. The branched patterns show a characteristic width w, which gives a linear relationship with the crystallization temperature on a semilogarithmic plot.
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Affiliation(s)
- F Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun, Jilin, 130022, PRC
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153
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154
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Mustafa A, McKinnon J, Christensen D, He T. Effects of micronization of flaxseed on nutrient disappearance in the gastrointestinal tract of steers. Anim Feed Sci Technol 2002. [DOI: 10.1016/s0377-8401(01)00337-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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155
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Abstract
Normal macroscopic and roentgenographic features of the skull of the ferret (Mustela putorius furo) were examined and described. Data were based on a sample of 100 (50 male and 50 female) adult ferrets of known body weight and age. The skull was described macroscopically according to six standard views, i.e. dorsal, lateral, ventral, caudal, cranial and midsagittal. The mandible was described separately. The roentgenographic characteristics of the ferret skull were demonstrated only in lateral and dorsoventral projections. Furthermore, the skull length and width as well as the minimum frontal width were measured, and skull indices were derived from relevant measurements. Sexual dimorphism was examined both morphologically and craniometrically. Besides the common features of a carnivore skull, the ferret skull is relatively elongated and flat with a short facial region. The skulls of adult male ferrets are about 17% longer and 22% wider than those of the females. Significant sexual dimorphism also exists regarding certain skull indices. The general features and some dimensional parameters of the adult ferret skull support the contention that the ferret would be an interesting and workable alternative animal model in craniofacial research.
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Affiliation(s)
- T He
- Department of Orthodontics, Faculty of Odontology, Göteborg University, Sweden.
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156
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Singer PM, Imai T, He T, Hayward MA, Cava RJ. (13)C NMR investigation of the superconductor MgCNi(3) up to 800 K. Phys Rev Lett 2001; 87:257601. [PMID: 11736604 DOI: 10.1103/physrevlett.87.257601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2001] [Indexed: 05/23/2023]
Abstract
We report (13)C NMR characterization of the new superconductor MgCNi(3) [T. He et al., Nature (London) 411, 54 (2001)]. We found that both the uniform spin susceptibility and the spin fluctuations show a strong enhancement with decreasing temperature, and saturate below approximately 50 K and approximately 20 K, respectively. The nuclear spin-lattice relaxation rate 1/(13)T(1) exhibits typical behavior for isotropic s-wave superconductivity with a coherence peak below T(c) = 7.0 K that grows with decreasing magnetic field.
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Affiliation(s)
- P M Singer
- Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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157
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Sather PJ, Ikonomou MG, Addison RF, He T, Ross PS, Fowler B. Similarity of an Aroclor-based and a full congener-based method in determining total PCBs and a modeling approach to estimate Aroclor speciation from congener-specific PCB data. Environ Sci Technol 2001; 35:4874-4880. [PMID: 11775164 DOI: 10.1021/es010921p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Polychlorinated biphenyls (PCBs) have entered the environment in North America as Aroclor technical mixtures. Most methods used for the determination of total PCB levels in environmental samples visually match patterns of sample peaks to those in Aroclor standards. Concern over the accuracy of Aroclor-based measurements on compositionally modified samples coupled with advancements in analytical techniques have led to congener-specific PCB analysis. In this study, the PCB data from 27 tissue samples determined by an Aroclor-based method and a full congener method were compared in terms of total PCB concentration to assess the reliability of this Aroclor technique for total PCB determination. Our data show a strong correlation between the sum of Aroclors and the total PCBs obtained from the full congener determinations. We also developed a model using the compositional data from three Aroclors (1242, 1254, and 1260) to determine the amount of compositional alteration from original Aroclor patterns in environmental samples. Full congener data, from a variety of tissue types and trophic levels, examined using this method showed that compositional modification from original Aroclor patterns increases with trophic level, with the greatest modification observed in seal and killer whale samples. This result agrees both with expectation and with what has been found in other studies. Such techniques, which connect congener-specific PCB data to Aroclor contamination, may prove useful to investigations into environmental and metabolic fate and transfer processes.
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Affiliation(s)
- P J Sather
- Institute of Ocean Sciences, Sidney, British Columbia, Canada
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158
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Toivola DM, Nieminen MI, Hesse M, He T, Baribault H, Magin TM, Omary MB, Eriksson JE. Disturbances in hepatic cell-cycle regulation in mice with assembly-deficient keratins 8/18. Hepatology 2001; 34:1174-83. [PMID: 11732007 DOI: 10.1053/jhep.2001.29374] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Simple epithelial tissues such as liver and pancreas express keratins 8 (K8) and 18 (K18) as their major intermediate filament proteins. K8 and K18 null mice and transgenic mice that express mutant K18 (K18C) manifest several hepatocyte abnormalities and demonstrate that K8/18 are important in maintaining liver tissue and cell integrity, although other potential functions remain uncharacterized. Here, we report an additional abnormal liver phenotype, which is similar in K8 null, K18 null, and K18C mouse models. Liver histologic examination showed large polynuclear areas that lacked cell membranes, desmosomal structures, and filamentous actin. Similar, but less prominent, areas were observed in the pancreas. The parenchyma outside the polynuclear areas displayed irregular sinusoidal structures and markedly enlarged nuclei. Most K8 null hepatocytes were positive for the proliferating cell nuclear antigen (PCNA) with a doubled DNA content in comparison with the predominantly PCNA-negative wild-type hepatocytes. The distribution of the 14-3-3zeta protein was also altered in K8 null mice. Taken together, our results indicate that absence of keratin filaments causes disturbances in cell-cycle regulation, driving cells into the S-G2 phase and causing aberrant cytokinesis. These effects could stem from disturbed functions of K8/18-dependent cell-cycle regulators, such as the signaling integrator, 14-3-3.
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Affiliation(s)
- D M Toivola
- Department of Medicine, Palo Alto Veterans Affairs Medical Center and Stanford University, Palo Alto, CA, USA
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159
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Yuan Y, He T, Wang L, Zeng J, Luo Y. [A comparison between the effects of albuterol and isoproterenol in bronchodilation test]. Hua Xi Yi Ke Da Xue Xue Bao 2001; 32:551-4. [PMID: 12528546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To compare albuterol with isoproterenol as a bronchodilator in pulmonary function test and their value in the diagnosis and differential diagnosis of asthma. METHODS Two groups (59 patients with asthma and 37 patients with COPD) were included in this study, and the patients of each group were randomly divided into 2 subgroups. The patients in the 2 subgroups inspired the two drugs in a cross-over by odd or even days. The pulmonary functions were evaluated. RESULTS The changing rates of pulmonary functions induced by the two drugs in the two groups were positively correlated (P < 0.005), The changing rates of FEV1, MMEF, Raw, sGaw induced by albuterol were higher than the ones induced by isoproterenol in patients with asthma(P < 0.02), however the changing rates of FVC and PEF in asthma cases and all the above parameters in COPD cases were not significantly different between the two drugs(P > 0.10). The comparison of positive case number between asthma and COPD cases induced by both drugs showed significant difference(P < 0.005); especially, when the positive rate of sGaw induced by albuterol in asthma cases reached 98%, the positive rates in COPD cases was generally much lower. CONCLUSION Bronchodilation test is a valuable diagnostic method for asthma. In this study, albuterol was superior to isoproterenol. The most sensitive index in bronchodilation test was sGaw, then in order, FEV1(92%), MMEF and Raw; the FVC and PEF were relatively insensitive.
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Affiliation(s)
- Y Yuan
- Department of Internal Medicine, First Affiliated Hospital, WCUMS, Chengdu 610041, China
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160
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Chen X, Feng Y, Luo Y, Yuan Y, He T, Zeng J. [The effect of leukotriene antagonist on the parameters of dose-response curve obtained after methacholine challenge test]. Hua Xi Yi Ke Da Xue Xue Bao 2001; 32:543-6. [PMID: 12528544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To investigate the effect of leukotriene antagonist (zafirlucast) on the parameters of dose-response curve (DRC) obtained after methacholine challenge test. METHODS A therapy trial was conducted with the use of zafirlucast in 20 cases of cough variant asthma (CVA) and 20 cases of asthma. Placebo was used in 4 cases of CVA and 10 cases of asthma for comparison with the two therapy groups respectively. Before and after the zafirlucast treatment a series of parameters of DRC were obtained after the methacholine challenge test and were calculated. These included the response threshold (PC35sGaw), the dose-response slope (DRS), the ratio of the area under the curve to the logarithm of the maximal concentration (AUC/1 g[Cmax]), and the maximal response. RESULTS Zafirlucast significantly increased the PC35sGaw in the CVA and asthma groups. It conspicuously decreased all the parameters of DRS and AUC/1 g[Cmax] except for maximal response in the cases of CVA, and it had no significant effects on all the parameters of DRS and AUC/1 g[Cmax] except for PC35sGaw in the cases of asthma. CONCLUSION Short-term use of Zafirlucast in asthmatic patients could improve the parameters of dose-response curve obtained after the methacholine challenge test.
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Affiliation(s)
- X Chen
- Department of Internal Medicine, First Affiliated Hospital, WCUMS, Chengdu 610041, China
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161
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Zhang YH, Chen DM, He T, Liu FC. Reaction of metallotetraphenylporphyrins on hydroxyl-modified silver colloid and Ag2O colloid by surface-enhanced Raman scattering. Spectrochim Acta A Mol Biomol Spectrosc 2001; 57:2599-2605. [PMID: 11765787 DOI: 10.1016/s1386-1425(01)00432-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper reports a novel reaction of metallotetraphenylporphyrins on hydroxyl-modified silver colloid and Ag2O colloid. Surface-enhanced Raman spectra of Ag(II) and Cu(II) complexes of tetraphenylporphyrin (TPP) adsorbed on the hydroxyl-modified Ag colloid and Ag2O colloid have been studied. The time-dependent SERS spectra of MTPP (M = Ag, Cu) on hydroxyl-modified Ag colloid were recorded and dramatic change on SERS spectra was observed. The final spectra were found to be strikingly different from the corresponding normal Raman spectra (NRS), with the appearance of new Raman bands at 1614. 1417, 947, 674 and 292 cm(-1). The UV-visible absorption spectrum of MTPP on hydroxyl-modified Ag colloid exhibits a broad shoulder near 460 nm. Similar spectral phenomena were also observed for AgTPP and CuTPP adsorbed on Ag2O colloid. The observed spectral alterations were ascribed to new species formation due to the irreducible oxidation of MTPP on the colloids.
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Affiliation(s)
- Y H Zhang
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
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162
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He T. [A discussion on Xian Yao Jing of the Yi nationality] (Chi). Zhonghua Yi Shi Za Zhi 2001; 15:169-2. [PMID: 11621176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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163
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Dorros G, Jaff MR, Dorros AM, Mathiak LM, He T. Tibioperoneal (outflow lesion) angioplasty can be used as primary treatment in 235 patients with critical limb ischemia: five-year follow-up. Circulation 2001; 104:2057-62. [PMID: 11673346 DOI: 10.1161/hc4201.097943] [Citation(s) in RCA: 243] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND In a prospective, nonrandomized, consecutive series of tibioperoneal vessel angioplasty (TPVA), critical limb ischemia (CLI) patients' data were analyzed with regard to immediate and follow-up success. METHODS AND RESULTS TPVA was successful in 270 of 284 critically ischemic limbs (95%), with 167 limbs (59%) requiring dilatation of 333 ipsilateral inflow obstructions to access and successfully dilate 486 of 529 (92%) tibioperoneal lesions. A clinical success (relief of rest pain or improvement of lower-extremity blood flow) was attained in 270 limbs at risk (95%). Clinical 5-year follow-up of 215 of 221 successful CLI patients (97%) with 266 successfully revascularized limbs revealed that bypass surgery occurred in 8% and significant amputations in 9% of limbs; 91% of the limbs were salvaged. The cohort's probability of survival was 56%: 58% for Fontaine class III and 33% for class IV patients. Class III compared with class IV patients had significantly (P<0.05) fewer surgical bypasses (3% versus 16%) and amputations: above-knee, 1% versus 4%; below-knee, 3% versus 12%; and transmetatarsal, <1% versus 21%. CONCLUSIONS TPVA, often in combination with inflow lesions, is an effective primary treatment for critical limb ischemia. The poor cumulative survival reflects the existence of severe comorbidities, which could potentially be affected by aggressive and effective cardiovascular diagnostic and therapeutic strategies.
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Affiliation(s)
- G Dorros
- William Dorros-Isadore Feuer Interventional Cardiovascular Disease Foundation Ltd, Grafton, WI, USA.
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164
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Chen X, Feng Y, Luo Y, Yuan Y, He T, Zeng J. [Measurement of the parameters of dose-response curve obtained after the methacholine challenge test]. Hua Xi Yi Ke Da Xue Xue Bao 2001; 32:430-4. [PMID: 12536585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To investigate the clinical value in the measurement of parameters of the dose-response curve (DRC) obtained after the methacholine challenge test. METHODS Twenty-seven cases of cough variant asthma (CVA), 29 of mild asthma, 19 of moderate asthma, and 15 healthy volunteers underwent the methacholine challenge test. The dose-response curves were constructed. The following parameters were calculated: position (PC35sGaw), dose-response curve (DRS), ratio of the area under the curve to the logarithm of the maximal concentration (AUC/lg[Cmax]) and maximal response. RESULTS A plateau appeared in 11 cases among the healthy subjects, while a plateau appeared only in 2 cases of CVA and 2 of asthma. There were no significant differences among the asthmatic groups in the measurements of PC35sGaw and AUC/lg[Cmax] (geometric mean PC35sGaw: mild asthmatics = 0.369, moderate asthmatics = 0.251, cough variant asthmatics = 0.547), AUC/lg[Cmax] was significantly greater in the asthmatic groups than in the normal group [AUC/lg [Cmax](mean +/- s): mild asthmatics = 24.7 +/- 4.7, moderate asthmatics = 26.6 +/- 4.3, cough variant asthmatics = 25.6 +/- 3.7, normal subjects = 15.5 +/- 4.3, P < 0.01]. DRS of moderate asthmatics was significantly greater as compared with cough variant asthmatics (geometric mean DRS: mild asthmatics = 30.761, moderate asthma-tics = 59.020, cough variant asthmatics = 19.231, P < 0.05), but there was no difference between the other groups. PC35sGaw was negatively correlated with DRS (r = 0.866, P < 0.001) and with AUC/lg[Cmax] (r = 0.502, P < 0.001). CONCLUSION Four parameters of DRC obtained after the methacholine challenge represent airway sensitivity and reactivity respectively. The parameters of DRC of asthmatic patients are different from those of normal subjects. The sensitivity is related to the reactivity, but they are not completely parallel with each other.
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Affiliation(s)
- X Chen
- Department of Internal Medicine, First Affiliated Hospital, WCUMS, Chengdu 610041, China
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165
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Han Y, He T, Huang DR, Pardo CA, Ransohoff RM. TNF-alpha mediates SDF-1 alpha-induced NF-kappa B activation and cytotoxic effects in primary astrocytes. J Clin Invest 2001; 108:425-35. [PMID: 11489936 PMCID: PMC209361 DOI: 10.1172/jci12629] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Stromal-derived cell factor-1 alpha (SDF-1 alpha; CXCL12) and its receptor, CXCR4, are constitutively expressed on neuroepithelial cells and are believed to be involved in both development and pathological processes, such as AIDS-associated neurologic disorders. Here, we demonstrate that SDF-1 alpha activates NF-kappa B, stimulates production of chemokines and cytokines, and induces cell death in primary astrocytes, effects that depend on ongoing secretion of TNF-alpha. SDF-1 alpha upregulated TNF-alpha mRNA and protein secretion, as well as TNF receptor 2 expression. TNF-alpha treatment mimicked SDF-1 alpha induction of NF-kappa B, IL-1 alpha/beta, and RANTES, as well as cell death; neutralizing antibodies against TNF-alpha opposed these responses. We also found that SDF-1 alpha activated Erk1 and Erk2 (Erk1/2) MAPK in a biphasic fashion. Early Erk1/2 activation was stimulated directly by SDF-1 alpha and late activation was mediated by TNF-alpha. PD98059 suppression of early Erk1/2 activation correlated with reduction of SDF-1 alpha-induced TNF-alpha expression. Late Erk1/2 activation was involved in TNF-alpha-stimulated NF-kappa B activation and cytokine induction. SDF-1 alpha was induced in reactive CXCR4-positive astrocytes near axotomized spinal cord motor neurons, consistent with autocrine SDF-1/CXCR4 signaling in these cells. We propose that these novel effects of SDF-1 alpha are relevant to the pathogenic and developmental roles of SDF-1 alpha in the CNS.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Astrocytes/cytology
- Astrocytes/drug effects
- Astrocytes/physiology
- Cell Death/drug effects
- Cells, Cultured
- Chemokine CCL5/genetics
- Chemokine CXCL12
- Chemokines, CXC/genetics
- Chemokines, CXC/pharmacology
- Chemokines, CXC/physiology
- DNA-Binding Proteins/metabolism
- Enzyme Activation/drug effects
- Gene Expression/drug effects
- I-kappa B Proteins
- Interleukin-1/genetics
- Mice
- Mitogen-Activated Protein Kinases/metabolism
- NF-KappaB Inhibitor alpha
- NF-kappa B/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, CXCR4/metabolism
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor, Type II
- Recombinant Proteins/genetics
- Recombinant Proteins/pharmacology
- Signal Transduction
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/physiology
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Affiliation(s)
- Y Han
- Department of Neurosciences, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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166
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Yildirim T, Gülseren O, Lynn JW, Brown CM, Udovic TJ, Huang Q, Rogado N, Regan KA, Hayward MA, Slusky JS, He T, Haas MK, Khalifah P, Inumaru K, Cava RJ. Giant anharmonicity and nonlinear electron-phonon coupling in MgB2: a combined first-principles calculation and neutron scattering study. Phys Rev Lett 2001; 87:037001. [PMID: 11461581 DOI: 10.1103/physrevlett.87.037001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2001] [Indexed: 05/23/2023]
Abstract
First-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB (2) are carried out and found to be in excellent agreement with our inelastic neutron scattering measurements. The numerical results reveal that the E(2g) in-plane boron phonons near the zone center are very anharmonic and strongly coupled to the planar B sigma bands near the Fermi level. This giant anharmonicity and nonlinear electron-phonon coupling is key to quantitatively explaining the observed high T(c) and boron isotope effect in MgB (2).
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Affiliation(s)
- T Yildirim
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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167
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Quan T, He T, Voorhees JJ, Fisher GJ. Ultraviolet irradiation blocks cellular responses to transforming growth factor-beta by down-regulating its type-II receptor and inducing Smad7. J Biol Chem 2001; 276:26349-56. [PMID: 11320083 DOI: 10.1074/jbc.m010835200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) is a multi-functional cytokine that regulates cell growth and differentiation. Cellular responses to TGF-beta are mediated through its cell surface receptor complex, which activates transcription factors Smad2 and Smad3. Here we report that UV irradiation of mink lung epithelial cells causes near complete inhibition of TGF-beta-induced Smad2/3-mediated gene expression. UV irradiation inhibited TGF-beta-induced phosphorylation of Smad2 and subsequent nuclear translocation and DNA binding of Smad2/3. Specific cell surface binding of TGF-beta was substantially reduced after UV irradiation. This loss of TGF-beta binding resulted from UV-induced down-regulation of TGF-beta type II receptor (T beta RII) mRNA and protein. UV irradiation significantly inhibited T beta RII promoter reporter constructs, indicating that UV reduction of T beta RII expression involved transcriptional repression. In contrast to its effects on T beta RII, UV irradiation rapidly induced Smad7 mRNA and protein. Smad7 is known to antagonize activation of Smad2/3 and thereby block TGF-beta-dependent gene expression. UV irradiation stimulated Smad7 promoter reporter constructs, indicating that increased Smad7 expression resulted, at least in part, from increased transcription. Overexpression of Smad7 protein to the level induced by UV irradiation inhibited TGF-beta-induced gene expression 30%. Maintaining T beta RII levels by overexpression of T beta RII prevented UV inhibition of TGF-beta responsiveness. Taken together, these data indicate that UV irradiation blocks cellular responsiveness to TGF-beta through two mechanisms that impair TGF-beta receptor function. The primary mechanism is down-regulation of T beta RII, and the secondary mechanism is induction of Smad7.
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Affiliation(s)
- T Quan
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan, 48109-0609, USA
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168
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He T, Carpinello L, Baker R, Knippenberg S, Das A, Winston L, McClanahan S. Safety of three toothbrushes. Am J Dent 2001; 14:123-6. [PMID: 11572286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
PURPOSE To assess the oral soft tissue safety and tolerability of two electric toothbrushes, the Crest Spin Brush and Colgate ActiBrush, and one manual toothbrush, the Oral B 40. MATERIALS AND METHODS A total of 104 subjects were enrolled in this single center, randomized, examiner-blind parallel study over a 4-wk test period. Subjects were randomized to treatment and were instructed to brush in their normal manner, twice per day for 60 s. A detailed oral soft tissue examination and interview were conducted by a trained clinician at baseline, 3 days and 4 wks to assess clinical signs and symptoms associated with use of the toothbrushes. RESULTS Over the 4-wk period, a total of 19 subjects (18% of the study population) were observed for signs/symptoms. The adverse events were distributed across test groups with 12 subjects in the Oral B 40 group, 4 subjects in the Crest Spin Brush group, and 3 subjects in the Colgate ActiBrush group experiencing at least one adverse event. All adverse events were mild in severity indicating the general safety of all three toothbrushes. The most frequently encountered event was localized gingivitis. The Oral B 40 test group was observed with more adverse events when compared to the Crest Spin Brush and Colgate ActiBrush at 4 wks but not at 3 days. The proportion of subjects experiencing an adverse event in the Crest Spin Brush test group was similar to that of Colgate ActiBrush group. All three toothbrushes were generally well tolerated by subjects enrolled in the study with the Crest Spin Brush and Colgate ActiBrush being the best tolerated. CLINICAL SIGNIFICANCE The results of this study indicated that abnormal oral soft tissue findings were distributed among the treatment groups, indicating that daily use of an electric toothbrush is at least as safe as a manual toothbrush.
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Affiliation(s)
- T He
- The Procter & Gamble Company, Cincinnati, Ohio, USA.
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169
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Li B, He T, Li J, Qiu M. [The effects of quercetin and isorhamnetin on oxidative modification of VLDL induced by Cu2+]. Hua Xi Yi Ke Da Xue Xue Bao 2001; 32:281-2, 285. [PMID: 12600108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
OBJECTIVE To observe the effects of quercetin(Que) and isorhamnetin (Iso) on the oxidative modification of very low density lipoprotein (VLDL). METHODS Human VLDL was prepared by one-step ultracentrifuge and oxidized by Cu2+ in vitro; Que and Iso in different concentrations were added to VLDL before incubation with Cu2+. The MDA, vitamin E contents and the activity of superoxide dismutase(SOD) in ox-VLDL were determined. RESULTS Compared with ox-VLDL group, Que and Iso decreased MDA production in a dependent concentration-manner, Que and Iso also elevated Vit E level and SOD activity markedly. CONCLUSION This experiment indicates that Que and Iso have similar inhibitory effects on the oxidative modification of VLDL.
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Affiliation(s)
- B Li
- Department of Biochemistry, School of Basic Medical Sciences, WCUMS, Chengdu 610041, China
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170
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Eom CB, Lee MK, Choi JH, Belenky LJ, Song X, Cooley LD, Naus MT, Patnaik S, Jiang J, Rikel M, Polyanskii A, Gurevich A, Cai XY, Bu SD, Babcock SE, Hellstrom EE, Larbalestier DC, Rogado N, Regan KA, Hayward MA, He T, Slusky JS, Inumaru K, Haas MK, Cava RJ. High critical current density and enhanced irreversibility field in superconducting MgB2 thin films. Nature 2001; 411:558-60. [PMID: 11385563 DOI: 10.1038/35079018] [Citation(s) in RCA: 442] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.
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Affiliation(s)
- C B Eom
- Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
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171
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He T, Huang Q, Ramirez AP, Wang Y, Regan KA, Rogado N, Hayward MA, Haas MK, Slusky JS, Inumara K, Zandbergen HW, Ong NP, Cava RJ. Superconductivity in the non-oxide perovskite MgCNi3. Nature 2001; 411:54-6. [PMID: 11333973 DOI: 10.1038/35075014] [Citation(s) in RCA: 530] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The interplay of magnetic interactions, the dimensionality of the crystal structure and electronic correlations in producing superconductivity is one of the dominant themes in the study of the electronic properties of complex materials. Although magnetic interactions and two-dimensional structures were long thought to be detrimental to the formation of a superconducting state, they are actually common features of both the high transition-temperature (Tc) copper oxides and low-Tc material Sr2RuO4, where they appear to be essential contributors to the exotic electronic states of these materials. Here we report that the perovskite-structured compound MgCNi3 is superconducting with a critical temperature of 8 K. This material is the three-dimensional analogue of the LnNi2B2C family of superconductors, which have critical temperatures up to 16 K (ref. 2). The itinerant electrons in both families of materials arise from the partial filling of the nickel d-states, which generally leads to ferromagnetism as is the case in metallic Ni. The high relative proportion of Ni in MgCNi3 suggests that magnetic interactions are important, and the lower Tc of this three-dimensional compound-when compared to the LnNi2B2C family-contrasts with conventional ideas regarding the origins of superconductivity.
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Affiliation(s)
- T He
- Department of Chemistry and Princeton Materials Institute, Princeton, New Jersey, USA
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172
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Monteverde M, Núñez-Regueiro M, Rogado N, Regan KA, Hayward MA, He T, Loureiro SM, Cava RJ. Pressure dependence of the superconducting transition temperature of magnesium diboride. Science 2001; 292:75-7. [PMID: 11283353 DOI: 10.1126/science.1059775] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We studied the pressure and temperature dependence of the electrical resistivity of the superconducting compound magnesium diboride (MgB(2)). The superconducting transition temperature decreases monotonically with pressure, being parabolic or linear, depending on samples. The rate of decrease under pressure is higher than in conventional superconductors. We discuss our results in terms of the semimetallic character of the electronic band structure of MgB(2).
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Affiliation(s)
- M Monteverde
- Centre de Recherches sur les Très Basses Températures, CNRS, BP166 Cedex 09, 38042 Grenoble, France
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173
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He T, Rao G, You R, Ge S, Zhang D. Genetic structure and heterozygosity variation between generations of Ophiopogon xylorrhizus (Liliaceae s.l.), an endemic species in Yunnan, southwest China. Biochem Genet 2001; 39:93-8. [PMID: 11521510 DOI: 10.1023/a:1010274109307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- T He
- Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R. China.
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174
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Slusky JS, Rogado N, Regan KA, Hayward MA, Khalifah P, He T, Inumaru K, Loureiro SM, Haas MK, Zandbergen HW, Cava RJ. Loss of superconductivity with the addition of Al to MgB2 and a structural transition in Mg1-x AlxB2. Nature 2001; 410:343-5. [PMID: 11268204 DOI: 10.1038/35066528] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The basic magnetic and electronic properties of most binary compounds have been well known for decades. The recent discovery of superconductivity at 39 K in the simple binary ceramic compound magnesium diboride, MgB2, was therefore surprising. Indeed, this material has been known and structurally characterized since the mid 1950s (ref. 2), and is readily available from chemical suppliers (it is commonly used as a starting material for chemical metathesis reactions). Here we show that the addition of electrons to MgB2, through partial substitution of Al for Mg, results in the loss of superconductivity. Associated with the Al substitution is a subtle but distinct structural transition, reflected in the partial collapse of the spacing between boron layers near an Al content of 10 per cent. This indicates that superconducting MgB2 is poised very near a structural instability at slightly higher electron concentrations.
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Affiliation(s)
- J S Slusky
- Department of Chemistry and Princeton Materials Institute, Princeton University, New Jersey 08544, USA
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175
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Larbalestier DC, Cooley LD, Rikel MO, Polyanskii AA, Jiang J, Patnaik S, Cai XY, Feldmann DM, Gurevich A, Squitieri AA, Naus MT, Eom CB, Hellstrom EE, Cava RJ, Regan KA, Rogado N, Hayward MA, He T, Slusky JS, Khalifah P, Inumaru K, Haas M. Strongly linked current flow in polycrystalline forms of the superconductor MgB2. Nature 2001; 410:186-9. [PMID: 11242073 DOI: 10.1038/35065559] [Citation(s) in RCA: 820] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery of superconductivity at 39 K in magnesium diboride, MgB2, raises many issues, a critical one being whether this material resembles a high-temperature copper oxide superconductor or a low-temperature metallic superconductor in terms of its behaviour in strong magnetic fields. Although the copper oxides exhibit very high transition temperatures, their in-field performance is compromized by their large anisotropy, the result of which is to restrict high bulk current densities to a region much less than the full magnetic-field-temperature (H-T) space over which superconductivity is found. Moreover, the weak coupling across grain boundaries makes transport current densities in untextured polycrystalline samples low and strongly sensitive to magnetic field. Here we report that, despite the multiphase, untextured, microscale, subdivided nature of our MgB2 samples, supercurrents flow throughout the material without exhibiting strong sensitivity to weak magnetic fields. Our combined magnetization, magneto-optical, microscopy and X-ray investigations show that the supercurrent density is mostly determined by flux pinning, rather than by the grain boundary connectivity. Our results therefore suggest that this new superconductor class is not compromized by weak-link problems, a conclusion of significance for practical applications if higher temperature analogues of this compound can be discovered.
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Affiliation(s)
- D C Larbalestier
- Applied Superconductivity Center, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706, USA.
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176
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Li J, Liu C, Li N, He T, Li B. [Scaling the SF-36 in a Chinese population]. Hua Xi Yi Ke Da Xue Xue Bao 2001; 32:36-8, 47. [PMID: 12733350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
OBJECTIVE To facilitate the cross-cultural comparison, we employed the principles of fuzzy mathematics in scaling the SF-36 in a Chinese population. METHODS We stratified an urban population according to the age, sex, and occupation, and selected 650 people to participate in the study. A total of 646 valid questionnaires were returned. In the 8 domains of the SF-36, the interval estimation of the scores of different alternative answers of 6 domains which have more than 2 alternative answers were conducted. RESULTS The fuzzy degrees of most interval estimations were less than 0.5, except 4 estimations in the domain "physical functions". The ordering of the scores of 8 domains was more similar to the original assumption by our scaling criteria than by the US scaling criteria. CONCLUSION The scaling criteria set in this study is more suitable for use in Chinese population and we suggest that the alternative answers of the domain "physical functions" be simplified to "yes" and "no".
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Affiliation(s)
- J Li
- Department of Social Medicine, School of Public Health, WCUMS, Chengdu 610041, China
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177
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Abstract
CXC chemokine receptor 4 (CXCR4) is a co-receptor for human immunodeficiency virus (HIV) infection and is believed to be involved in the pathogenesis of AIDS-associated neurologic disorders and brain tumors. The physiological roles of CXCR4 in developmental patterning of the nervous and hematopoietic system; gastrointestinal angiogenesis; and cardiac organogenesis were established by studies in gene-targeted mice. Studies on CXCR4 expression and regulation in neuroepithelial cells are fundamental for understanding its physiopathologic roles in the central nervous system (CNS). We show here that CXCR4 expression by primary mouse astrocytes is suppressed by exposure to tumor necrosis factor-alpha (TNF-alpha). TNF-alpha caused a pronounced down-regulation of CXCR4 mRNA in a dose- and time-dependent manner. TNF-alpha-mediated decrease of CXCR4 mRNA accumulation resulted in decreased CXCR4 protein expression. As a result, the ability of stromal cell-derived factor-1alpha (SDF-1alpha) to induce activation of MAP kinases, Erk1/2 was impaired. The half life of CXCR4 mRNA in the presence and absence of TNF-alpha stimulation was comparable, suggesting that TNF-alpha down-regulated CXCR4 mRNA at the transcriptional level. These results suggest that TNF-alpha could modulate HIV and brain tumor pathogenesis and immune-mediated inflammation in the central nervous system (CNS) by regulation of CXCR4 expression.
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Affiliation(s)
- Y Han
- Department of Neurosciences, The Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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178
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Hu Z, Wang L, Ou Z, Huang L, Lai R, He T, Dong J, Chen G. Preparation of aerogel beryllium borate with supercritical carbon dioxide drying. POWDER TECHNOL 2001. [DOI: 10.1016/s0032-5910(00)00317-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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179
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Aref A, Thornton D, Youssef E, He T, Tekyi-Mensah S, Denton L, Ezzell G. Dosimetric improvements following 3D planning of tangential breast irradiation. Int J Radiat Oncol Biol Phys 2000; 48:1569-74. [PMID: 11121663 DOI: 10.1016/s0360-3016(00)00808-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate the dosimetric difference between a simple radiation therapy plan utilizing a single contour and a more complex three-dimensional (3D) plan utilizing multiple contours, lung inhomogeneity correction, and dose-based compensators. METHODS AND MATERIALS This is a study of the radiation therapy (RT) plans of 85 patients with early breast cancer. All patients were considered for breast-conserving management and treated by conventional tangential fields technique. Two plans were generated for each patient. The first RT plan was based on a single contour taken at the central axis and utilized two wedges. The second RT plan was generated by using the 3D planning system to design dose-based compensators after lung inhomogeneity correction had been made. The endpoints of the study were the comparison between the volumes receiving greater than 105% and greater than 110% of the reference dose, as well as the magnitude of the treated volume maximum dose. Dosimetric improvement was defined to be of significant value if the volume receiving > 105% of one plan was reduced by at least 50% with the absolute difference between the volumes being 5% or greater. The dosimetric improvements in 49 3D plans (58%) were considered of significant value. Patients' field separation and breast size did not predict the magnitude of improvement in dosimetry. CONCLUSION Dose-based compensator plans significantly reduced the volumes receiving > 105%, >110%, and volume maximum dose.
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Affiliation(s)
- A Aref
- Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA.
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180
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Gimenez-Bonafé P, Laszczak M, Kasinsky HE, Lemke MJ, Lewis JD, Iskandar M, He T, Ikonomou MG, White FM, Hunt DF, Chiva M, Ausió J. Characterization and evolutionary relevance of the sperm nuclear basic proteins from stickleback fish. Mol Reprod Dev 2000; 57:185-93. [PMID: 10984419 DOI: 10.1002/1098-2795(200010)57:2<185::aid-mrd10>3.0.co;2-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have characterized the sperm nuclear basic proteins (SNBPs) of the sticklebacks in the suborder Gasterosteoidei. The complete amino acid sequence of the protamines from Aulorhynchus flavidus, Pungitius pungitius, Gasterosteus aculeatus, (anadromous) and G. wheatlandi, as well as the sequences of the protamines of several species pairs of freshwater G. aculeatus, have been determined. Analysis of the primary structure of these proteins has shown that: a) despite the relatively low amino acid complexity and small molecular mass of these basic proteins, they are very good molecular markers at the generic level. The bootstrap parsimony analysis using their sequences provides a phylogenetic relationship for the old anadromous species of Gasterosteoidei which is identical to that obtained from morphological and behavioral analysis; b) the comparison of the sequences also suggests that protamines from the suborder Gasterosteoidei have most likely evolved from a common gene in the early Acanthopterygii by an extension of the carboxy terminal portion of the molecule; c) protamines are not good markers for recent postglacial freshwater isolates of G. aculeatus. However, in the unique case of Enos Lake (British Columbia), we have been able to detect an additional minor protamine component in the benthic forms of G. aculeatus that is not present in the limnetic forms. Thus, this new protamine must have appeared during the past 12,000 years concomitantly with the speciation of benthics and limnetics in this lake.
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Affiliation(s)
- P Gimenez-Bonafé
- Departament d'Enginyería Química, ETSEIB, Universitat Politécnica de Catalunya, Barcelona, Spain
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181
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Zhang L, Chung C, Hu BS, He T, Guo Y, Kim AJ, Skulsky E, Jin X, Hurley A, Ramratnam B, Markowitz M, Ho DD. Genetic characterization of rebounding HIV-1 after cessation of highly active antiretroviral therapy. J Clin Invest 2000; 106:839-45. [PMID: 11018071 PMCID: PMC517816 DOI: 10.1172/jci10565] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Despite prolonged treatment with highly active antiretroviral therapy (HAART), infectious HIV-1 continues to replicate and to reside latently in resting memory CD4(+) T lymphocytes, creating a major obstacle to HIV-1 eradication. It is therefore not surprising to observe a prompt viral rebound after discontinuation of HAART. The nature of the rebounding virus, however, remains undefined. We now report on the genetic characterization of rebounding viruses in eight patients in whom plasma viremia was undetectable throughout about 3 years of HAART. Taking advantage of the extensive length polymorphism in HIV-1 env, we found that in five patients who did not show HIV-1 replication during treatment, the rebound virus was identical to those isolated from the latent reservoir. In three other patients, two of whom had been free of plasma viremia but had showed some residual viral replication, the rebound virus was genetically different from the latent reservoir virus, corresponding instead to minor viral variants detected during the course of treatment in lymphoid tissues. We conclude that in cases with apparent complete HIV-1 suppression by HAART, viral rebound after cessation of therapy could have originated from the activation of virus from the latent reservoir. In patients with incomplete suppression by chemotherapy, however, the viral rebound is likely triggered by ongoing, low-level replication of HIV-1, perhaps occurring in lymphoid tissues.
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Affiliation(s)
- L Zhang
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016, USA
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182
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Maayan S, Zhang L, Shinar E, Ho J, He T, Manni N, Kostrikis LG, Neumann AU. Evidence for recent selection of the CCR5-delta 32 deletion from differences in its frequency between Ashkenazi and Sephardi Jews. Genes Immun 2000; 1:358-61. [PMID: 11196681 DOI: 10.1038/sj.gene.6363690] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have shown higher frequencies of the CCR5-delta 32 allele and the CCR5-delta 32/delta 32 genotype, which confers protection against HIV infection, in northern Europe as compared to Mediterranean countries. Here, we analyse the prevalence of CCR5-delta 32 in 922 HIV seronegative blood donors in Israel to verify its frequency in Jews of Ashkenazi and Sephardi origin. A significant difference (P < 0.001) was found between the CCR5-delta 32 allele frequency in Ashkenazi (13.8%) vs (4.9%) Jews. In contrast, no significant difference was observed in the frequency of the CCR2-641 mutation between Ashkenazi (9.2%) and Sephardi (13.4%) Jews. Using the Island model we calculate that a minimal genetic migration rate of 3% per generation would have been necessary if the higher CCR5-delta 32 prevalence in Ashkenazi is to be fully explained by mixing with the indigenous north-European populations. This putative migration rate is 20-fold higher than that currently estimated from other genes, and would correspond to a non-realistic minimal current admixture of 80%. Thus, our results suggest that a positive selection process for CCR5-delta 32 should have occurred in northern Europe at most a 1000 years ago, after the Ashkenazi Jews separated from their Sephardi kin and moved to north Europe.
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Affiliation(s)
- S Maayan
- Hadassah Hospital, Jerusalem 91000, Israel
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183
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Yano-Higuchi K, Takamatsu N, He T, Umeda M, Ishikawa I. Prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in subgingival microflora of Japanese patients with adult and rapidly progressive periodontitis. J Clin Periodontol 2000; 27:597-602. [PMID: 10959786 DOI: 10.1034/j.1600-051x.2000.027008597.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND, AIMS This study investigated the prevalence of Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans among various periodontitis patients and healthy individuals in Japan, and correlated it with clinical parameters. METHOD Subgingival plaque samples were collected from 21 patients with adult periodontitis (AP), 8 with rapidly progressive periodontitis (RPP) and 15 healthy individuals. RESULTS The frequency detected in culture was as follows: B. forsythus was found in 47.6% of AP sites and in 37.5% of RPP sites. P. gingivalis was identified in 64.3% of AP and 59.4% of RPP sites. A. actinomycetemcomitans was detected in 4.8% of AP and 3.1% of RPP sites. The 3 species were detected in only 2 of the healthy individuals. The proportion of B. forsythus in the total microflora in culture was 0.07% in the healthy group, 4.1% in AP and 2.4% in RPP. The proportions of P. gingivalis were 0% in the healthy group, 18.8% in AP and 16.2% in RPP. The proportion of A. actinomycetemcomitans was very low in all 3 groups. A DNA probe detected B. forsythus in 78.6% of AP and 65.6% of RPP sites, as well as P.gingivalis in 58.3% of AP and 59.4% of RPP sites. A. actinomycetemcomitans was detected in only 1.2% of AP sites. The 3 species were undetectable in the healthy group. CONCLUSIONS The prevalence and the proportion of B. forsythus and P. gingivalis were significantly correlated with clinical parameters, suggesting that B. forsythus and P. gingivalis are closely related to AP and RPP in the Japanese population.
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Affiliation(s)
- K Yano-Higuchi
- Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University, Japan.
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184
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He T, Lu G, Li J, Chen G. [Chaos in electroencephalogram]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2000; 17:209-13. [PMID: 12557782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The history and current situation of EEG study were reviewed in the paper, with an emphasis on the application and the latest developments of chaos in EEG analysis. The problems in present study and the proposals for future investigations were finally discussed.
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Affiliation(s)
- T He
- Department of Biomedical Engineering, First Military Medical University, Guangzhou 510515
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185
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Yuan Y, Wang Y, Zeng J, He T. [Application of model 4650 type I compressor atomizer in bronchial challenge test]. Hua Xi Yi Ke Da Xue Xue Bao 2000; 31:262-4. [PMID: 12515156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
This study was directed to the feasibility of applying a simple atomizer-model 4650 type I (abbrev. M)-to bronchial challenge test. 92 cases of asthma were divided into 3 groups randomly. All of them were subjected to the bronchial challenge test by M atomizer, and by standard Dosimeter atomizer (abbrev. D) as a comparison. In the test by M atomizer, the times for inspiring challenging medicine were 1, 1.5 and 2 minutes for the 3 groups respectively, while the time for D atomizer was 1 minute for all. The results showed no significant differences (P > 0.2-0.5) between the two atomizers in the 3 groups, their values were linear correlated. When the inspiring time was 1 minute for both M and D, the test needed a higher concentration of challenging medicine for M than for D, their coefficient of correlation (r = 0.285) was relatively low. When inspiring time postponed to 1.5 minute for M, the difference in medicine concentration between M and D was smallest (-0.075 g/L), r = 0.665. However, a further postponed inspiring time to 2 minute for M reversely broadened their difference. These results indicated that the efficiency of M atomizer was a little lower than that of D, postponing the inspiring time for M could make up this weakness. A 1.5 minute inspiring time for M atomizer was the suggestion. Some modifications on M atomizer were done by us for a better efficiency, and the cheap and popular M atomizer could be a good replacement in bronchial challenge test.
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Affiliation(s)
- Y Yuan
- Department of Internal Medicine, First Affiliated Hospital, WCUMS, Chengdu 610041
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186
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He T, Wei D, Fabris D, Fenselau C. Intracellular sequestration of anti-tumor drugs by metallothionein. Cell Mol Biol (Noisy-le-grand) 2000; 46:383-92. [PMID: 10774927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Acquired drug resistance is one of the most important problems in cancer chemotherapy. One of the mechanisms proposed to contribute to this phenomenon is the sequestration of alkylating agents by metallothionein (MT) in vivo. In this study cadmium-induced human bladder tumor T24 cells were exposed to the therapeutic agents chlorambucil and melphalan. MT-2a, was shown by capillary electrophoresis to comprise 56% of the MT isoforms in induced cells, and drug adducts of MT-2a were isolated and characterized by HPLC and electrospray ionization mass spectrometry. One to four equivalents of drug were found to be covalently adducted. Major binding sites on metallothionein were located in the C-terminal domain by peptide mapping, consistent with previous studies in vitro.
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Affiliation(s)
- T He
- Dept of Chemistry and Biochemistry, University of Maryland Baltimore County, 21250, USA
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187
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Yuan Y, Wang Y, Yang L, He T, Zeng J, Luo Y. [Comparison of efficiency and merits of two parameters for bronchial challenge test by use of a simple equation]. Hua Xi Yi Ke Da Xue Xue Bao 2000; 31:86-7, 97. [PMID: 12501623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The aim of this study was to investigate the relationship, merit and weakness of two parameters--the FEV1 and sGaw--for bronchial challenge test. The 36 cases of asthma patients were subjected to bronchial challenge test with FEV1 and sGaw as the test parameters simultaneously. A simple calculative equation was used. The Mch (challenge medicine) concentrations for a 20% decrease of FEV1(PC20FEV1) and for a 35% decrease of sGaw (PC35 sGaw) were figured out. The results showed that PC20 FEV1 and PC35 sGaw were 2.73 +/- 2.92 g/L and 1.50 +/- 2.03 g/L respectively. A significant difference between them was noted (P < 0.05), and their coefficient of correlation r = 0.738. The linear regression equation was PC35sGaw = 0.100 + 0.513 x PC20 FEV1. PC35sGaw was obviously lower than PC20 FEV1; the Mch amount for PC35sGaw was almost one half of that for PC20 FEV1, which indicated that sGaw was more sensitive than FEV1 as a parameter for bronchial challenge test. The FEV1, however, needs a relatively low standard of instrument, so it is more obtainable and popularized.
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Affiliation(s)
- Y Yuan
- Department of Internal Medicine, The First Affiliated Hospital, WCUMS, Chengdu 610041
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188
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Wang Y, Luo Y, Yuan Y, He T, Zeng J. [Measurement and clinical use of recoil pressure of the respiratory system]. Hua Xi Yi Ke Da Xue Xue Bao 1999; 30:422-3. [PMID: 11387958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Using the principle that the difference of MIP (maximal inspiratory mouth pressure) between RV (residual volume) and FRC (functional residual capacity) equals Prs (recoil pressure of the respiratory system) at RV, we performed the measurement of Prs at RV in 20 normal subjects, 90 patients with COPD (chronic obstructive pulmonary disease) and 15 patients with ILF (interstitial lung fibrosis). We also performed the correlation analysis of Prs at RV and RV/TLC (total lung capacity) %. The results indicated the Prs values at RV (-2.8 +/- 0.5 kPa) in normal subjects measured in this manner was in accord with the values reported by other authors abroad. The Prs in patients with emphysema decreased and it was highly and negatively correlated with RV/TLC% (r = -0.872), but the Prs in patients with ILF was increased. The results suggest that this method for measurement of Prs is simple, reliable, and clinically useful.
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Affiliation(s)
- Y Wang
- Department of Internal Medicine, WCUMS, Chengdu 610041
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189
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He T, Huang CY, Chen H, Hou YH. Effects of spinach powder fat-soluble extract on proliferation of human gastric adenocarcinoma cells. Biomed Environ Sci 1999; 12:247-252. [PMID: 10840580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Four kinds of assays were used to study the effect of a fat-soluble extract of spinach powder (SPFE) on the proliferation of human gastric adenocarcinoma cell line (SGC-7901) in vitro. These studies included: (i) cell growth assay, (ii) colony forming assay, (iii) MTT colorimetric assay, and (iv) 3H-TdR incorporation assay. The concentrations of SPFE expressed as the level of beta-carotene in the medium were 2 x 10(-8), 2 x 10(-7) and 2 x 10(-6) mol/L beta-carotene in assay (i)-(iii), but 4 x 10(-8), 4 x 10(-7) and 4 x 10(-6) mol/L beta-carotene in assay (iv) respectively. The results indicated that SPFE inhibited the proliferation and colony forming ability of SGC-7901 cells. And in MTT assay, SPFE inhibited the viability of SGC-7901 cells, but no inhibitory effect of SPFE was observed on the viability of lymphocytes in peripheral blood of healthy people. Finally, in the 3H-TdR incorporation test, both SPFE and beta-carotene showed significant inhibitory effects on DNA synthesis in SGC-7901 cells, but SPFE was more effective than beta-carotene.
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Affiliation(s)
- T He
- Department of Nutrition and Food Hygiene, School of Public Health, West China University of Medical Sciences (WCUMS), Chengdu, China
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190
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Affiliation(s)
- A. J. Hu
- The State Key Laboratory of Engineering Plastics, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - J. Y. Hao
- The State Key Laboratory of Engineering Plastics, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - T. He
- The State Key Laboratory of Engineering Plastics, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - S. Y. Yang
- The State Key Laboratory of Engineering Plastics, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
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191
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He T, Nishihara T, Demuth DR, Ishikawa I. A novel insertion sequence increases the expression of leukotoxicity in Actinobacillus actinomycetemcomitans clinical isolates. J Periodontol 1999; 70:1261-8. [PMID: 10588488 DOI: 10.1902/jop.1999.70.11.1261] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The expression of leukotoxin varies among Actinobacillus actinomycetemcomitans strains and is dependent in part on the structure of the ltx promoter region. Highly leukotoxic strains, characterized by a 530 base pair (bp) deletion within the ltx promoter, have been associated with juvenile periodontitis in the United States and Europe. In the present study, we analyzed the ltx promoter structure to elucidate whether A. actinomycetemcomitans from Japanese periodontitis patients exhibits the highly toxic phenotype. METHODS Forty-five A. actinomycetemcomitans strains, including 43 clinical isolates, the highly leukotoxic strain JP2, and a minimally leukotoxic strain 652 were used in the study. The ltx promoter structure was analyzed by polymerase chain reaction (PCR), with oligonucleotide primers focusing the ltx promoter region, and nucleotide sequencing. Leukotoxic activity was determined by trypan blue exclusion. Western blotting assay was performed to detect the level of leukotoxin polypeptide. RESULTS A 495 bp PCR product was amplified from JP2, a 1025 bp product from 652 and 41 of the clinical isolates, and a 1926 bp product from the remaining two clinical isolates (AaIS1, AaIS2). Sequencing of the 1926 bp PCR fragment showed that it was similar to that of strain 652 but contained an 886 bp region that was identified as an insertion sequence (IS). Both AaIs strains expressed high levels of leukotoxicity, similar to strain JP2. In addition, a mutant (AaIS-) that had lost the IS element expressed a significantly lower level of leukotoxicity compared with AaIS strains. Furthermore, the levels of leukotoxin polypeptide expressed by these strains were consistent with their whole cell leukotoxicity. CONCLUSIONS A. actinomycetemcomitans clinical strains which were isolated from Japanese periodontitis patients do not possess the 530 bp ltx promoter deletion. The results of this study suggest that a high level of leukotoxin expression correlates with the insertion of the transposable DNA element.
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Affiliation(s)
- T He
- Department of Periodontology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
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192
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Aref A, Thornton D, Youssef E, He T, Tekyi-Mensah S, Denton L, Ezzell G. Dosimetric imrovements following 3-D planning of tangential breast irradiation. Eur J Cancer 1999. [DOI: 10.1016/s0959-8049(99)80748-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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193
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Huang Y, He T, Domann FE. Decreased expression of manganese superoxide dismutase in transformed cells is associated with increased cytosine methylation of the SOD2 gene. DNA Cell Biol 1999; 18:643-52. [PMID: 10463060 DOI: 10.1089/104454999315051] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tumor cells express lower levels of manganese superoxide dismutase (MnSOD) than their normal counterparts. Enforced expression of MnSOD reverses the malignant phenotype of many transformed cells, suggesting that SOD2 is a tumor suppressor. The SOD2 gene contains a large CpG island spanning > 3.5 kb that starts near the 5' edge of the promoter and extends into intron 2. We hypothesized that the difference in SOD2 expression between tumor cells and their normal cell counterparts might be secondary to differences in their cytosine methylation patterns in this CpG island. To test this hypothesis, we analyzed the methylation status of the SOD2 gene in two cell line models that show differential MnSOD expression between normal and SV40-transformed cells: WI38 and MRC5 and their SV40-transformed variants, WI38-VA and MRC5-VA. We subdivided the SOD2 gene CpG island into 10 individual regions for analysis by bisulfite genomic sequencing. A region located in intron 2 displayed a significant increase in cytosine methylation in both transformed cell lines that expressed low levels of MnSOD mRNA compared with their normal cell counterparts. Recent studies by others have shown that SOD2 intron 2 is a potent transcriptional enhancer. The association between increased cytosine methylation of the SOD2 intron 2 region and decreased MnSOD expression in transformed cells compared with their normal counterparts suggests that an epigenetic mechanism contributes to the differential SOD2 gene expression between these normal and SV40-transformed cells.
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Affiliation(s)
- Y Huang
- Department of Radiology, College of Medicine, University of Iowa, Iowa City 52242, USA
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194
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He T, Chandramouli N, Fu E, Wu A, Wang YK. Analysis of reduced and oxidized forms of cytochrome c by capillary electrophoresis and capillary electrophoresis-mass spectrometry. Anal Biochem 1999; 271:189-92. [PMID: 10419636 DOI: 10.1006/abio.1999.4133] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- T He
- Core Technologies Area, Novartis Institute for Biomedical Research, Novartis Pharmaceuticals Corporation, Summit, New Jersey 07901, USA
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195
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Chen M, He T, Qiu M. [Application of enzyme-linked immunosorbent assay for cholecystokinin]. Hua Xi Yi Ke Da Xue Xue Bao 1999; 30:217-9. [PMID: 12212065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
An enzyme-linked immunosorbent assay for octapeptide cholecystokinin (CCK) has been developed. Using this method we distinguished two kinds of CCK-related peptides and is also useful for identified the compounds with CCK-like structure in tissue extracts, as well as different antipeptide antisera. The results showed that this method could be applied to preliminary structure analysis of CCK.
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Affiliation(s)
- M Chen
- Department of Biochemistry, School of Basic Medical Sciences, WCUMS, Chengdu 610041
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196
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Takamatsu N, Yano K, He T, Umeda M, Ishikawa I. Effect of initial periodontal therapy on the frequency of detecting Bacteroides forsythus, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans. J Periodontol 1999; 70:574-80. [PMID: 10397511 DOI: 10.1902/jop.1999.70.6.574] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans have been described as periodontopathic bacteria, and their presence in subgingival pockets can lead to development of periodontal disease. Until now, clinical parameters have been used to evaluate the effect of conventional periodontal treatment without microbiological parameters. The present study examined the microbiological effects of initial periodontal therapy using DNA probes and the polymerase chain reaction (PCR). METHODS Twenty-six patients with periodontitis, 10 males and 16 females, were given instructions regarding oral hygiene, then thoroughly treated by conventional scaling and root planing. Bacterial samples were collected on paper points from 4 sites per patient at baseline and after initial therapy (total: 104 sites). Clinical parameters including probing depth, attachment level, and bleeding on probing were also recorded for each site at baseline and after therapy. A DNA probe kit was used to monitor the frequency of B. forsythus, P. gingivalis, and A. actinomycetemcomitans, the last of which was identified by PCR. RESULTS At baseline, B. forsythus was the bacterium most frequently detected. DNA probe analysis also showed that more than half of the sites were colonized by both B. forsythus and P. gingivalis. Initial therapy resulted in significant clinical improvement such as significant reduction in the frequency of B. forsythus and P. gingivalis detected using the DNA probe. A. actinomycetemcomitans was difficult to detect using the DNA probe, but PCR indicated that levels of A. actinomycetemcomitans did not significantly decrease. CONCLUSIONS These results indicate that initial conventional therapy can eliminate B. forsythus and P. gingivalis, but not A. actinomycetemcomitans. When levels of these bacteria decreased to below-detectable levels, clinical improvement was significant. These results indicate that monitoring levels of these three periodontopathic bacteria may render periodontal therapy more effective and accurate.
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Affiliation(s)
- N Takamatsu
- Department of Periodontology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan
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197
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Abstract
We describe here a procedure by capillary electrophoresis-mass spectrometry (CE-MS) for the direct analysis of urine samples on diagnostic metabolites, which are present in patient urine with metabolic disorders. The method was demonstrated using urine samples spiked with diagnostic metabolites, including glutathione for gamma-glutamyl transpeptidase deficiency, pyroglutamate for generalized glutathione deficiency, adenylosuccinate for adenylosuccinase deficiency, omithine for gyrate atrophy, histidine for histidinemia, and homogentisic acid for alcaptonuria, at concentrations similar to those found in patients' urine. A coaxial sheath liquid flow was used for coupling CE and MS in electrospray ionization mode. Identification of the metabolites is based on their molecular weights and fragmentation patterns. The CE-MS method is highly specific and sensitive comparing to the previously reported method using migration time and UV absorption for identification. It should find broad application in clinical and pharmaceutical research and development.
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Affiliation(s)
- T He
- Core Technologies Area, Discovery Research, Novartis Pharmaceuticals Corporation, Summit, NJ 07901, USA
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198
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Zhao Y, Shi Y, He T, Zhang H, Chen S, Zhang B. [Direct intramuscular injection of pSV-VEGF(165) augments capillaries formation in a rabbit model of hindlimb ischemia]. Zhonghua Wai Ke Za Zhi 1999; 37:211-3. [PMID: 11829821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To investigate an easier and safer clinical method of gene therapy for treating arterial ischemic diseases in the lower extremity. METHODS Recombinant plasmid pSV-VEGF(165) constructed in vitro was directly injected into the ischemic hindlimb muscles in rabbit models. 30 days after gene transfer, the capillary density and the capillary to muscle fiber ratio were determined histochemically in the resected samples. RESULTS The capillary density and the capillary to muscle fiber ratio were significantly higher for pSV-VEGF(165) transfected group than for control group, particularly increased in the shank of the hindlimbs. CONCLUSIONS Direct intramuscular injection of pSV-VEGF(165) was an easier and efficient gene therapy method, and it significantly augmented the capillary formation in ischemic limbs.
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Affiliation(s)
- Y Zhao
- Department of Vascular Surgery, Renji Hospital, Shanghai Second Medical University, Shanghai 200001
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199
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Alecu R, Alecu M, Loomis T, Ochran T, He T. Traditional and MLC based dose compensator design for patients with hip prostheses undergoing pelvic radiation therapy. Med Dosim 1999; 24:33-7. [PMID: 10100163 DOI: 10.1016/s0958-3947(98)00044-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Perturbations in the dose distribution caused by a hip prosthesis when treating pelvic malignancies can result in unacceptable dose inhomogeneities within the target volume. Our results, obtained by in vivo exit dose measurements with diodes, showed a 55% reduction in the dose at the exit dmax of a lateral 15 MV photon beam after passing through a bilateral cobalt-chrome alloy hip prosthesis. Such an inhomogeneous dose distribution may decrease the curability. Solutions such as treatment techniques to avoid the prosthesis are often not the best choice as the dose to the rectum may be unacceptably high. In this work an alternative method of dose compensator is presented. Two types of dose compensators were designed based on a 3-D treatment planning system and CT images of a pelvic phantom containing a hip prosthesis: one was fabricated from a polyethylene-lead slab in the representation of step fringes and placed on a tray in the path of the beam while the other was produced by the use of several fields shaped with a multileaf collimator. The calculation procedures developed by the authors for generating the compensators are described. Results of film measurements performed in a phantom with and without the compensators in place are discussed.
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Affiliation(s)
- R Alecu
- Physician Reliance Network & Texas Oncology, P.A., Texas Cancer Center, Sherman 75090, USA
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200
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He Q, Wang W, Wu G, Wang J, Fen M, He T, Pan L, Zhao Y. [The mechanism of absorbance increase and decrease in liquid-core optical fiber spectrophotometry]. Guang Pu Xue Yu Guang Pu Fen Xi 1999; 19:95-97. [PMID: 15818930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this paper, the mechanism of absorbance increase and decrease in liquid-core optical fiber spectrophotometry is studied based on optical fiber theory and the results demonstrate that the absorbance increase and decrease result from the light scatter and propagation in optical fiber and depend on the scatter of samples and solvents. The experimental results are given.
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Affiliation(s)
- Q He
- Xinjiang Institute of Physics, Academia Sinica, 830011 Wulumuqi
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