| 18261. |
- Zhang, Yanwen, et al.
(författare)
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Evaluate scintillation response over a continuous energy region
- 2008
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 55:3, s. 1097-1101
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed fast analysis technique utilizing a time of flight (TOF) telescope is demonstrated to obtain relevant quantitative data on material scintillation response to energetic He particles. With the superior energy resolution and fast response of the TOF telescope, the energy of individual particles before impinging on a scintillator crystal can be determined with a high count rate, allowing quantitative study of material performance over a continuous energy range in a relatively short time. Scintillation performance in terms of light output, nonlinearity and energy resolution in bismuth germanate (BGO) and europium-doped calcium fluoride (CaF2:Eu) crystals is demonstrated, and the corresponding energy resolution is compared with gamma-ray tests on the same crystals.
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| 18262. |
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| 18263. |
- Zhang, Yaping, et al.
(författare)
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IL-1{beta} Induced Transcriptional Up-regulation of Bradykinin B1 and B2 Receptors in Murine Airways.
- 2007
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - 1535-4989 .- 1044-1549. ; 36:6, s. 697-705
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Tidskriftsartikel (refereegranskat)abstract
- Hyperresponsiveness to bronchoconstrictor stimuli is a major pathophysiologic feature of asthma, but the molecular mechanisms behind this are not fully understood. The release of TNF-alpha and IL-1 beta during the inflammatory process is believed to play an important role in airway hyperresponsiveness. We have previously demonstrated, using a murine in vitro model of chronic airway inflammation, that TNF-alpha up-regulated bradykinin B-1 and B-2 receptors in the airway smooth muscle. By using the same model, the present study was designed to investigate the effects of IL-1 beta and its interaction with TNF-alpha on the expression of bradykinin B-1 and B-2 receptors in mouse tracheal smooth muscle. IL-1 beta up-regulated bradykinin B-1 and B2 receptor expression and increased contractile response to bradykinin B-1 and B-2 receptor agonists (des-Argl-bradykinin and bradykinin, respectively) in the tracheal smooth muscle. Transcriptional inhibitor actinomycin D, c-Jun N-terminal kinase (INK) inhibitors SP600125 and TAT-TI-JIP(153-163), but not extracellular signal-regulated kinase 1 and 2 (ERK 1/2) inhibitor PD98059, significantly attenuated this up-regulation, indicating that a transcriptional mechanism and intracellular JNK signal transduction pathway were involved. In addition, IL-1 beta did not affect bradykinin B-1 and B-2 receptor mRNA stability. Remicade, an anti-TNF-a antibody, markedly suppressed IL-1 beta-incluced up-regulation of bradykinin B-1 and B-2 receptors, suggesting that TNF-alpha was involved in the up-regulation, which is further supported by the fact that IL-1 beta enhanced TNF-alpha mRNA expression in the tracheae. Intracellular INK pathway and TNF-alpha might provide key links between inflammatory mediators like IL-1 beta and airway hyperresponsiveness to bradykinin.
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| 18264. |
- Zhang, Yaping, et al.
(författare)
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IL-1 beta induces murine airway 5-HT2A receptor hyperresponsiveness via a non-transcriptional MAPK-dependent mechanism
- 2007
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Ingår i: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-9921 .- 1465-993X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Interleukin 1 beta ( IL- I beta) is found in bronchoalveolar lavage fluids from asthmatic patients and plays an important role in normal immunoregulatory processes but also in pathophysiological inflammatory responses. The present study was designed to investigate if IL- I beta could be involved in the development of airway hyperresponsiveness and if transcriptional mechanisms, epithelium contractile factors and mitogen-activated protein kinase ( MAPK) pathways are involved in IL- I beta effect. Methods: The effect of IL- I beta on 5-hydroxytryptamine ( 5- HT) induced bronchoconstriction was evaluated in an in-vitro model for assessment of long-term effects of inflammatory mediators on the airway smooth muscle. Murine tracheal segments were cultured up to 8 days in the absence or presence of IL- I beta with subsequent evaluation in a myograph system, along with mRNA quantification, focusing on the role of the epithelium, acetylcholine release, transcriptional mechanisms and MAPK activity. Results: During control conditions, 5- HT induced a relatively weak contraction. Presence of IL- I beta increased this response in a time-and concentration-dependent way. The increased concentration-effect curves could be shifted rightwards in a parallel manner by ketanserin, a selective 5- HT2A receptor antagonist, indicating that the responses are mediated by 5- HT2A receptors. The mRNA levels of 5- HT2A receptors were not changed as a consequence of the IL- I beta treatment and actinomycin D, a general transcriptional inhibitor, failed to affect the contractile response, suggesting a non-transcriptional mechanism behind this phenomenon. Neither the removal of the epithelium nor the addition of atropine affected the IL- I beta induced enhancement of 5- HT2A receptor-mediated contractile response. Application of inhibitors for c-Jun N-terminal kinase ( JNK), p38 and extracellular signal-regulated kinase 1 and 2 ( ERK1/2) showed that the signaling pathways for JNK and ERK1/2 dominated only in cultured segments ( control) whereas JNK and p38 dominated in segments treated with IL- I beta. Conclusion: IL- I beta induces murine airway hyperresponsiveness, via a non-transcriptional up-regulation of 5- HT2A receptor-mediated contractile response. The increase of 5- HT contraction is unrelated to epithelial and cholinergic factors, but is dependent on IL- I beta- induced changes of MAPK pathways. The fact that IL- I beta can alter airway responses to contractile agents such as 5- HT, via alteration of the intracellular MAPK signal transduction pathways, might provide a new concept for future treatment of asthma.
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| 18265. |
- Zhang, Yaping, et al.
(författare)
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Long-term exposure to IL-1beta enhances Toll-IL-1 receptor-mediated inflammatory signaling in murine airway hyperresponsiveness.
- 2009
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Ingår i: European Cytokine Network. - : John Libbey Eurotext. - 1952-4005 .- 1148-5493. ; 20:3, s. 148-156
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Tidskriftsartikel (refereegranskat)abstract
- Toll-interleukin-1 (Toll-IL-1) receptor signaling may play a key role in the development of airway hyperreactivity (AHR) and chronic airway inflammatory diseases such as asthma. Previously, we have demonstrated that pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), induce AHR. However, the underlying intracellular signaling mechanisms that lead to AHR remain elusive. In order to see if the Toll-IL-1 receptor-mediated inflammatory signal pathways are involved in the development of AHR, the present study was designed to use a real-time PCR array, a sensitive and powerful tool, consisting of 84 genes related to Toll-IL-1 receptor signal pathways. Murine tracheal segments were organ cultured for four days in the presence and absence of IL-1beta. The Toll-IL-1 receptor-mediated inflammatory signal gene profile was studied using the real-time PCR-based cDNA array. The key gene expressions that were altered were verified by immunohistochemistry using confocal microscopy. Tracheal ring segment contractile responsiveness to the inflammatory mediator bradykinin was monitored using a sensitive myograph system. The results showed that after exposed to IL-1beta for four days, the tracheal segments exhibited increased mRNA expression of 67 genes (out of the 84 genes in the array), although expression reached statistical significance for only 16 of these genes. There were 14 genes that showed only a tendency towards a decrease in mRNA expression following IL-1beta treatment. Immunohistochemistry confirmed that protein expression for CD14, RP105, MCP-1 and phosphorylated IkappaB-alpha were increased in both the airway epithelial and smooth muscle cells. In order to link the activation of Toll-IL-1 receptor-mediated inflammatory signal mechanisms to the AHR, the anti-inflammatory drug dexamethasone, was used. Dexamethasone not only completely abolished the IL-1beta-induced AHR to bradykinin, but also abrogated the increased mRNA expression for inflammatory mediators, IL-6, IFN-gamma and Cox-2. In conclusion, long-term exposure of murine airway to IL-1beta induces up- and down-regulation of mRNA expression for Toll-IL-1 receptor signal molecules, with a significant increase in the expression of 16 genes that contribute to the development of airway inflammation and AHR. Understanding cytokine-induced activation of the Toll-IL-1 receptor-mediated inflammatory signaling mechanisms may provide new options for the treatment of airway inflammation and AHR.
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| 18266. |
- Zhang, Y, et al.
(författare)
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Medial temporal lobe atrophy increases the specificity of cerebrospinal fluid biomarkers in Alzheimer disease with minor cerebrovascular changes.
- 2009
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Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 50:6, s. 674-81
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although cerebrospinal fluid (CSF) biomarkers and medial temporal lobe atrophy (MTA) contribute to the diagnosis of Alzheimer disease (AD), they may not be specific. Relatively little is known about how they correlate with each other. PURPOSE: To identify the validity of the radiological linear measurements of brain atrophy in AD diagnosis by examining the correlation with CSF biomarkers and by examining if specificity could be improved in classification of AD from controls, when the linear measurements are combined with the CSF biomarkers. MATERIAL AND METHODS: 59 controls (20 male/39 female, age 73+/-8 years), 162 pure AD patients (49/113, 74+/-7 years), and 86 AD patients with minor cerebrovascular changes (CVC) (31/55, 77+/-5 years), aged between 52 and 94 years, were recruited from the Malmo Alzheimer Study. AD patients were subgrouped into "pure AD" and "AD + CVC" in order to clarify the possible influence of CVC on atrophy or CSF biomarkers in AD patients. Abeta42, T-tau, and P-tau in CSF were examined. Computed tomography (CT) linear measurements were performed, which included temporal horn ratio and suprasellar cistern ratio that reflect MTA. RESULTS: Compared with the 14 significant correlations between the CT measurements and three CSF biomarkers in the pure AD group, there was only one significant correlation in the AD + CVC group and one in the control group. In particular, P-tau correlates with temporal horn ratio only in pure AD. When the CT measurements were added with CSF biomarkers as independent variables in discriminant analysis, the percentage of correct classification of AD + CVC from controls increased from 79.5% (only CSF biomarkers) to 84.6% (combined CT measurements with CSF biomarkers). However, little was changed in the pure AD group. CONCLUSION: P-tau correlates with the linear CT measure of MTA only in pure AD without CVC. Combined with the measure of MTA, the specificity of CSF biomarkers can be increased, but only in AD + CVC. The linear measurements of MTA are of value in AD diagnosis.
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| 18267. |
- Zhang, Yanwen, et al.
(författare)
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Radiation detector resolution over a continuous energy range
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
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Tidskriftsartikel (refereegranskat)abstract
- An ion approach is demonstrated to determine energy resolution in both semiconductor detectors and scintillators over a continuous energy range. For semiconductors, the energy resolution of a silicon detector was measured as a function of helium ion energy, and the values from extrapolation to high energies are in good agreement with the literature data from alpha measurements. For scintillators, benchmark crystals subject to He+ irradiation were investigated, and the agreement of energy resolution between the ion and gamma measurements indicates that the ion approach can be used to predict the energy resolution of the candidate materials in thin-film form or small crystals when large crystals necessary for gamma-ray measurements are unavailable.
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| 18268. |
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| 18269. |
- Zhang, Yi, et al.
(författare)
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Usefulness of computed tomography linear measurements in diagnosing Alzheimer's disease.
- 2008
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 49:1, s. 91-97
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Tidskriftsartikel (refereegranskat)abstract
- Background: Medial temporal lobe atrophy (MTA) is an early sign of Alzheimer's disease (AD). The current method of choice for measuring MTA is volumetric measurement based on 3D magnetic resonance imaging (MRI), but this complicated method has not been implemented clinically. Purpose: To investigate whether simple computed tomography (CT) linear measurements of the brain could be of value in AD workup. Material and Methods: Fifty-nine healthy control subjects and 248 AD subjects were recruited. They were evaluated using a comprehensive clinical workup. A series of linear CT measurements were obtained from brain CT. Results: In discriminant analysis, the temporal horn ratio and the suprasellar cistern ratio were the atrophy factors that contributed most significantly to the diagnoses. Combined with other clinical factors (apolipoprotein E4 genotype), a correct AD classification of 90.2% was achieved. Conclusion: CT linear measurements could be of value in the workup of AD patients, considering the inexpensiveness and availability of CT as well as the simplicity of linear measurements.
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| 18270. |
- Zhang, Zhong-Fa, et al.
(författare)
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Detection of submicroscopic constitutional chromosome aberrations in clinical diagnostics: a validation of the practical performance of different array platforms
- 2008
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1476-5438 .- 1018-4813. ; 16:7, s. 786-792
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Tidskriftsartikel (refereegranskat)abstract
- For several decades etiological diagnosis of patients with idiopathic mental retardation (MR) and multiple congenital anomalies (MCA) has relied on chromosome analysis by karyotyping. Conventional karyotyping allows a genome-wide detection of chromosomal abnormalities but has a limited resolution. Recently, array-based comparative genomic hybridization (array CGH) technologies have been developed to evaluate DNA copy-number alterations across the whole-genome at a much higher resolution. It has proven to be an effective tool for detection of submicroscopic chromosome abnormalities causing congenital disorders and has recently been adopted for clinical applications. Here, we investigated four high-density array platforms with a theoretical resolution <= 100 kb: 33K tiling path BAC array, 500K Affymetrix SNP array, 385K NimbleGen oligonucleotide array and 244K Agilent oligonucleotide array for their robustness and implementation in our diagnostic setting. We evaluated the practical performance based on the detection of 10 previously characterized abnormalities whose size ranged from 100 kb to 3 Mb. Furthermore, array data analysis was performed using four computer programs developed for each corresponding platform to test their effective ability of reliable copy-number detection and their user-friendliness. All tested platforms provided sensitive performances, but our experience showed that accurate and user-friendly computer programs are of crucial importance for reliable copy-number detection.
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