701
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Kristianpoller N, Weiss D, Chen R. Effects of photostimulation in natural zircon. RADIAT MEAS 2006. [DOI: 10.1016/j.radmeas.2006.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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702
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Pagonis V, Chen R, Lawless J. Nonmonotonic dose dependence of OSL intensity due to competition during irradiation and readout. RADIAT MEAS 2006. [DOI: 10.1016/j.radmeas.2006.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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703
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Lan T, Zhang S, Liu B, Li X, Chen R, Song W. Differentiating sex chromosomes of the dioecious Spinacia oleracea L. (spinach) by FISH of 45S rDNA. Cytogenet Genome Res 2006; 114:175-7. [PMID: 16825771 DOI: 10.1159/000093335] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 11/29/2005] [Indexed: 11/19/2022] Open
Abstract
Spinacia oleracea L. (spinach) is a dioecious species with both male and female plants having 2n = 2x = 12 chromosomes, consisting of two large metacentrics, two long subtelocentrics, two short subtelocentrics, two acrocentrics, and four submetacentrics. The location of 45S rDNA was investigated on metaphase chromosomes using fluorescence in situ hybridization (FISH). The numbers of 45S rDNA foci in diploid sets of chromosomes from females was six and from males was five. All the fluorescent foci lay in secondary constrictions and the satellites. Our results indicate that an XY-type sex chromosome system could be present in spinach where the Y chromosome lacks a 45S RNA focus.
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704
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Silasi D, Rutherford TJ, Schwartz PE, Chen R, Alvero A, Visintin I, Mor G. Novel method for predicting chemoresistance to paclitaxel in epithelial ovarian cancer patients. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.15007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
15007 Background: No available test exists to guide the selection of effective chemotherapeutic regimen in recurrent ovarian cancer. Preliminary studies in our lab have identified a protein, MyD88, a major component in the inflammatory pathway, to be highly expressed in epithelial ovarian cancer cells that exhibit primary or acquired Paclitaxel chemoresistance. The objective of this study was to develop a sensitive approach that can detect expression of MyD88 in ovarian cancer tissue. We report the development of a test based on Laser capture microdissection that allows detection of MyD88 in a 6000 cell sample. Methods: Tumor tissue was obtained at surgery from epithelial ovarian cancer patients and snap-frozen in liquid nitrogen. Eight micron sections were prepared on polyethylene covered glass slides and tumor cells were dissected with a Laser capture microdissection system. Protein expression was detected by Western blot analysis. Results: Protein expression was detected by Western blot analysis in 1000 microdissected cells. An inverse correlation was observed between MyD88 expression in tumor cells and clinical response to Paclitaxel. Furthermore, this method allows the isolation of CD-45 positive cells from the tumor and analysis of their protein expression. Conclusions: We describe for the first time a method that will allow us to predict chemoresistance. Laser capture microdissection is a powerful technique that can be used to study the protein profile of each of the cellular components present in the tumor microenvironment. This technique will facilitate our understanding of the proteins necessary for tumor growth and may help to identify novel markers or potential protein targets. No significant financial relationships to disclose.
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705
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Kulkarni PM, Chen R, Monberg M, Obasaju CK. Efficacy and safety of pemetrexed (P) in elderly cancer patients (pts). J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.8544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
8544 Background: P, a novel multitargeted antifolate, has demonstrated antitumor activity in a broad range of tumor types. Approximately 60% of all new cases of cancer and 70% of all cancer-related deaths occur in the elderly population. However, few studies have specifically analyzed the utility of chemotherapy in this population. The objective of this posthoc analysis was to understand the efficacy and tolerability of pemetrexed (alone or in combination) when used in the elderly cancer population. Methods: Data from three pemetrexed registration trials conducted between April 1999 and February 2003 were pooled together. Pts in these studies were diagnosed with malignant pleural mesothelioma, NSCLC, or advanced pancreatic cancer. Pts receiving P as monotherapy or in combination with another drug (gemcitabine or cisplatin) who received at least one cycle of therapy were included in this analysis (n=764). In all studies, P 500 mg/m2 was administered every 21 days. Demographics, efficacy, and safety data from pts receiving P were stratified by age ± 65 years. Kaplan-Meier method was used to estimate survival and time to PD. Cox regression model was also used to test the survival effect of pemetrexed on age after adjusting for disease stage, performance status, gender, and type of tumors, the prognostic factors considered to influence survival. Results: * P<.05 from fisher’s exact test. The adjusted hazard ratio of elderly patients over younger patients was 1.074 with p-value 0.42. Conclusions: P produced similar treatment effects in older and younger patients and appeared to be well tolerated in the elderly population. CTC grade 3/4 Lab and Non-Lab toxicity between two age groups were similar except, as expected, the elderly group had modestly higher myelosuppression. Non-hematologic toxicities were similar between the two age groups. [Table: see text] [Table: see text]
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706
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Treat J, Belani CP, Schiller J, Monberg MJ, Cunneen J, Chen R, Ye Z, Obasaju CK. Gemcitabine (G) plus carboplatin (C) at AUC 5 demonstrates reduced grade 4 thrombocytopenia rate compared to AUC 5.5 in first line therapy of patients with advanced stage NSCLC. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.7130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
7130 Background: GC is a commonly used regimen in first-line therapy of advanced stage NSCLC. Various dosing of carboplatin in the GC regimen produces different toxicity profiles. This report summarizes three recent large clinical trials, including the Coalition Trial, using GC regimens that had comparable efficacy to other modern doublets. Methods: Three trials using GC as first-line treatment for advanced NSCLC with recent best response and toxicity data were selected. Pt populations were similarly defined, including measurable or evaluable Stage IIIB (with pleural effusion) or IV disease. All utilized similar 21-d regimens of G 1000 mg/m2 d 1,8 and C AUC 5.5 or 5.0 d1. Results: Despite a grade 4-thrombocytopenia rate of 12% in Trial 1 (Coalition) there was no difference in serious bleeding events compared to the other arms (paclitaxel/carboplatin and paclitaxel/gemcitabine). Discussion: In these three trials, 1126 pts with advanced NSCLC were treated with first-line GC. This database of 743 patients assessed for safety suggests that GC AUC 5 results in a 4.7% (95% CI: 3.3–6.5%) grade 4-thrombocytopenia rate with similar anti-tumor efficacy. The regimen of G 1000 mg/m2 on d1, 8 with C AUC 5 on d1 of a 21-d cycle may be optimal for treatment of advanced NSCLC. [Table: see text] [Table: see text]
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707
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Hsieh TJ, Chen R, Zhang SL, Liu F, Brezniceanu ML, Whiteside CI, Fantus IG, Ingelfinger JR, Hamet P, Chan JSD. Upregulation of osteopontin gene expression in diabetic rat proximal tubular cells revealed by microarray profiling. Kidney Int 2006; 69:1005-15. [PMID: 16528250 DOI: 10.1038/sj.ki.5000206] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Progression of diabetic nephropathy appears directly related to renal tubulointerstitial injury, but the involved genes are incompletely delineated. To identify such genes, DNA microarray analysis was performed with RNA from renal proximal tubules (RPTs) of streptozotocin-induced diabetic Wistar rats, spontaneously diabetic BioBreeding rats, and rat immortalized renal proximal tubular cells (IRPTCs) exposed to high glucose (25 mM) medium for 2 weeks. Osteopontin (OPN) mRNA expression was quantified by real time-quantitative polymerase chain reaction (RT-qPCR) or conventional reverse transcriptase-polymerase chain reaction (RT-PCR). OPN mRNA expression was upregulated (5-70-fold increase) in diabetic rat RPTs and in IRPTCs chronically exposed to high glucose compared to control RPTs and IRPTCs. High glucose, angiotensin II, phorbol 12-myristate 13-acetate and transforming growth factor-beta 1 (TGF-beta1) stimulated OPN mRNA expression in IRPTCs in a dose- and time-dependent manner. This effect was inhibited by tiron, taurine, diphenylene iodinium, losartan, perindopril, calphostin C, or LY 379196 but not PD123319. IRPTCs overexpressing dominant-negative protein kinase C-beta 1 (PKC-beta1) cDNA or antisense TGF-beta1 cDNA prevented the high glucose effect on OPN mRNA expression. We concluded that high glucose-mediated increases in OPN gene expression in diabetic rat RPTs and IRPTCs are mediated, at least in part, via reactive oxygen species generation, intrarenal rennin-angiotensin system activation, TGF-beta1 expression, and PKC-beta1 signaling.
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708
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Chen JY, Zheng MF, Jing ZH, Wang YG, Zhu QK, Chen R. Case Report: A Left Donor Lung Implanted in the Recipient’s Right Thorax for the Therapy of Pulmonary Fibrosis. Transplant Proc 2006; 38:1535-7. [PMID: 16797352 DOI: 10.1016/j.transproceed.2006.03.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Indexed: 11/30/2022]
Abstract
A 68-year patient suffering from pulmonary fibrosis underwent single lung transplantation on April 4, 2005. Because the ipsilateral donor lung was severely damaged, we had to implant the contralateral lung--the left lung--to the right thorax, and finally this patient recovered.
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709
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Tan A, Chen R. PROSPECTIVE STUDY. BPH: GYRUS LOOP VS. CONVENTIONAL TURP - 2-YEARS' FOLLOW-UP. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1569-9056(06)61156-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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710
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Wu JL, Wu QP, Huang JM, Chen R, Cai M, Tan JB. Effects of L-malate on physical stamina and activities of enzymes related to the malate-aspartate shuttle in liver of mice. Physiol Res 2006; 56:213-220. [PMID: 16555951 DOI: 10.33549/physiolres.930937] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
L-malate, a tricarboxylic acid cycle (TCA) intermediate, plays an important role in transporting NADH from cytosol to mitochondria for energy production and may be involved in the beneficial effects of improving physical stamina. In the present study, we investigated the effects of L-malate on the performance of forced swimming time and blood biochemical parameters related to fatigue - blood urea nitrogen (BUN), glucose (Glc), creatine kinase (CK),total protein (TP) and lactic acid (LA). To investigate the effects of L-malate on the malate-aspartate shuttle and energy metabolism in mice, the activities of enzymes related to the malate-aspartate shuttle were measured. L-malate was orally administered to mice continuously for 30 days using a feeding atraumatic needle. The swimming time was increased by 26.1 % and 28.5 %, respectively, in the 0.210 g/kg and 0.630 g/kg L-malate-treated group compared with the control group. There were no differences in the concentrations of Glc, BUN and TP between the L-malate-treated groups and the control groups. However, the levels of CK were significantly decreased in the L-malate-treated groups. The results predict a potential benefit of L-malate for improving physical stamina and minimizing muscle damage during swimming exercise. The activities of cytosolic and mitochondrial malate dehydrogenase were significantly elevated in the L-malate-treated group compared with the control group. These enzymatic activities may be useful indicators for evaluating changes affecting the malate-aspartate shuttle and energy metabolism in the liver of mice.
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711
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Prabhuram J, Zhao TS, Tang ZK, Chen R, Liang ZX. Multiwalled Carbon Nanotube Supported PtRu for the Anode of Direct Methanol Fuel Cells. J Phys Chem B 2006; 110:5245-52. [PMID: 16539454 DOI: 10.1021/jp0567063] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The activity of the methanol oxidation reaction of a multiwalled carbon nanotube (MWCNT)-supported PtRu catalyst was investigated and compared with the Vulcan XC-72 carbon-supported catalyst. The PtRu nanoparticles with 1:1 and 7:3 atomic ratios (with similar PtRu loadings and morphological structures) were deposited both on the MWCNTs and on the carbon. Cyclicvoltammetry results demonstrated that the MWCNT-supported PtRu catalyst exhibited a higher mass activity (mA mg(-1) of PtRu) for the methanol oxidation reaction than the carbon-supported PtRu under the condition that both catalysts possess more or less the same PtRu loadings, particle sizes, dispersions, and electrochemical surface area. The direct methanol fuel cell performance test data showed that MWCNT-supported PtRu catalysts yielded about 35-39% higher power densities than the carbon-supported PtRu.
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712
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Molnar GF, Sailer A, Gunraj CA, Cunic DI, Wennberg RA, Lozano AM, Chen R. Changes in motor cortex excitability with stimulation of anterior thalamus in epilepsy. Neurology 2006; 66:566-71. [PMID: 16505313 DOI: 10.1212/01.wnl.0000198254.08581.6b] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Deep brain stimulation (DBS) is an effective treatment for movement disorders and pain. Recently, bilateral DBS of the anterior nucleus of thalamus (AN) was performed for the treatment of intractable epilepsy. This surgery reduced seizure frequency in an initial group of patients. However, its physiologic effects on the cortex and mechanisms of action remain poorly understood. Different classes of antiepileptic drugs (AEDs) have distinct effects on the excitatory and inhibitory circuits in the motor cortex, which can be studied noninvasively by transcranial magnetic stimulation (TMS). OBJECTIVE To examine the effects of bilateral AN DBS on motor cortex excitability in epilepsy and compare these to the known effects of AEDs. METHODS Cortical excitability was assessed in five medicated epilepsy patients with bilateral stimulators implanted in the anterior thalamus and nine healthy controls. Single and paired TMS were used to examine cortical inhibitory and facilitatory circuits. Electromyography was recorded from the dominant hand, and TMS was applied over the contralateral motor cortex. Patients were studied during DBS turned off (OFF condition), DBS with cycling stimulation mode (1 minute on, 5 minutes off; CYCLE), and DBS with continuous stimulation (CONTINUOUS) in random order on 3 consecutive days. RESULTS Motor thresholds were increased in the patients regardless of DBS condition. Active short-interval intracortical inhibition (SICI) was significantly reduced in the OFF and CYCLE conditions but returned toward normal levels in the CONTINUOUS condition. Rest SICI, long interval intracortical inhibition, and silent period duration were unchanged. CONCLUSIONS Increased short-interval intracortical inhibition with continuous deep brain stimulation (DBS) suggests that thalamic DBS might drive cortical inhibitory circuits, similar to antiepileptic drugs that enhance gamma-aminobutyric acid inhibition.
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713
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Palmer AJ, Chen R, Valentine WJ, Roze S, Bregman B, Mehin N, Gabriel S. Cost-consequence analysis in a French setting of screening and optimal treatment of nephropathy in hypertensive patients with type 2 diabetes. DIABETES & METABOLISM 2006; 32:69-76. [PMID: 16523189 DOI: 10.1016/s1262-3636(07)70249-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM Forty percent of hypertensive type 2 diabetes patients develop nephropathy (microalbuminuria/overt nephropathy), indicating end organ damage, increased risk of cardiovascular disease (CVD), and death. In France, screening rates and nephropathy treatment are suboptimal. We assessed the health economic impact of nephropathy screening in hypertensive patients with type 2 diabetes followed by optimal antihypertensive/nephroprotective therapy in those who have nephropathy in France. METHODS A Markov/Monte Carlo model simulated lifetime impacts of screening for albuminuria (microalbuminuria/overt nephropathy) using semi-quantitative urine dipsticks in a primary care setting, and subsequent addition of irbesartan 300 mg to conventional therapy in hypertensive type 2 diabetes patients identified as having nephropathy. Progression from no renal disease to end-stage renal disease (ESRD) was simulated. Probabilities, utilities and costs of CVD events, medications and ESRD treatment came from published sources. Cumulative incidence of ESRD, life expectancy, quality-adjusted life years (QALYs) and direct costs were projected. Second-order Monte Carlo simulation accounted for uncertainty in multiple parameters. Costs and QALYs were discounted at 3% annually. RESULTS Screening and optimized treatment led to a 42% reduction in the cumulative incidence of ESRD from 10.1 +/- 9.9% without screening to 5.8 +/- 5.7%, improvements in life expectancy of 0.38 +/- 0.59 years, improvements of 0.29 +/- 0.32 QALYs, and decreased costs of Euro 4,812 +/- 7,882/patient over 25 years. Sensitivity analysis showed that the results were robust. Screening was most beneficial when performed in younger patients. CONCLUSION In hypertensive patients with type 2 diabetes, screening for albuminuria followed by optimal antihypertensive/nephroprotective treatment improves patient outcomes and leads to cost savings in France.
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714
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Donohue K, Tang D, Chau D, Andrews H, Chen R, Yadavalli S, Perera F, Chanock S, Miller R. Ethnic Differences in Frequencies of Single Nucleotide Polymorphisms for Glutathione S-Transferase (GST) and IL13. J Allergy Clin Immunol 2006. [DOI: 10.1016/j.jaci.2005.12.648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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715
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Abstract
Previously, we reported that intracellular Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis were present within buccal epithelial cells from human subjects, as lesser components of a polymicrobial flora. In this study, we further characterized that intracellular flora by using the same double-labeling techniques to identify Fusobacterium nucleatum, Prevotella intermedia, oral Campylobacter species, Eikenella corrodens, Treponema denticola, Gemella haemolysans, Granulicatella adiacens, and total streptococci within buccal epithelial cells. All those species were found within buccal cells. In every case, species recognized by green-labeled species-specific probes were accompanied by other bacteria recognized only by a red-labeled universal probe. Streptococci appeared to be a major component of the polymicrobial intracellular flora, being present at a level from one to two logs greater than the next most common species (G. adiacens). This is similar to what is observed in oral biofilms, where diverse species interact in complex communities that often are dominated by streptococci.
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716
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Kristianpoller N, Weiss D, Chen R. Optical and dosimetric properties of zircon. RADIATION PROTECTION DOSIMETRY 2006; 119:267-70. [PMID: 16702245 DOI: 10.1093/rpd/nci570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Irradiation effects were investigated in zircon crystals by methods of optical absorption and luminescence. Special attention was given to the effects of vacuum ultraviolet (VUV) radiation. The same main thermoluminescence (TL) peaks with the same thermal activation energies appeared after VUV as after X- or beta irradiation, indicating that the same traps were induced by the different irradiations. TL excitation spectra in the VUV showed an increase <220 nm and maxima near 190 and 140 nm. Excitation spectra of phototransferred TL (PTTL) and optically stimulated luminescence (OSL) were also measured. Most TL emission bands also appeared in the X-luminescence, PTTL and OSL. Dosimetric properties such as the TL radiation sensitivity, thermal stability of radiation-induced defects and TL dose dependence were also investigated. The radiation sensitivity of zircon was by an order of magnitude lower than that of TLD-100. The 355 K TL peak showed linear dose dependence only up to approximately 500 Gy and the 520 K peak up to approximately 1800 Gy.
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717
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Hanajima R, Chen R, Ashby P, Lozano AM, Hutchison WD, Davis KD, Dostrovsky JO. Intraoperative recording of the very fast oscillatory activities evoked by median nerve stimulation in the human thalamus. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2006; 59:121-6. [PMID: 16893102 DOI: 10.1016/s1567-424x(09)70021-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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718
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Norja P, Hokynar K, Aaltonen LM, Chen R, Ranki A, Partio E, Kiviluoto O, Davidkin I, Leivo T, Eis-Hübinger A, Schneider B, Fischer HP, Tolba R, Vapalahti O, Vaheri A, Söderlund-Venermo M, Hedman K. Bioportfolio: lifelong tissue persistence of new and old parvoviruses. J Clin Virol 2006. [DOI: 10.1016/s1386-6532(06)80718-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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719
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Xu F, Ji J, Li L, Chen R, Hu W. Tu-P7:84 JE MRNA expression and monocyte chemoattractant protein-1 expression in the adventitial fibroblasts of aortic root in apolipoprotein gene knockout mice before the intimal lesion formation. ATHEROSCLEROSIS SUPP 2006. [DOI: 10.1016/s1567-5688(06)80791-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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720
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Lo D, Lawless JL, Chen R. Superlinear dose dependence of high temperature thermoluminescence peaks in Al2O3:C. RADIATION PROTECTION DOSIMETRY 2006; 119:71-4. [PMID: 16644951 DOI: 10.1093/rpd/nci642] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report on strong superlinearity of high temperature (300-700 degrees C) thermoluminescence (TL) peaks in alpha-Al2O3:C powder. The main dosimetric peak at approximately 200 degrees C, previously found to exhibit slight superlinearity, is now shown to yield a slope of approximately 1.15 on a log(intensity) vs. log(dose) curve. Higher temperature peaks at approximately 320, 450 and 650 degrees C, previously reported following UV and X-ray excitation, have now been observed after beta irradiation and showed stronger superlinearity. Using a blue filter, the weak peak at approximately 320 degrees C started about quadratically and the slope on the log-log scale decreased gradually from 2 to about unity at approximately 100 Gy. The two higher temperature peaks at approximately 450 and approximately 650 degrees C also exhibited a strong superlinear dose dependence in this dose range, with an average slope of approximately 2. Roughly similar behaviour has been found when a UV filter was used. The possible explanation of the strong superlinearity is discussed.
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721
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Chen R, Lo D, Lawless JL. Non-monotonic dose dependence of thermoluminescence. RADIATION PROTECTION DOSIMETRY 2006; 119:33-6. [PMID: 16644974 DOI: 10.1093/rpd/nci599] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The thermoluminescence (TL) intensity in different materials is usually a monotonic increasing function of the dose, which quite often reaches a saturation value. In several materials, however, non-monotonic dose dependence has been observed. The TL intensity reached a maximum at a certain dose and decreased at higher ones. Some authors refer to this effect as 'radiation damage'. In the present work, we show that the non-monotonic dependence can easily be demonstrated to result from competition between transitions model with two trapping states and two kinds of recombination centres. Two kinds of competition are considered. One in which competition during excitation dominates, the filling of the active luminescence centre is non-monotonic, and the resulting TL is non-monotonic. In the other, the filling of traps and centres is monotonically increasing, but the competition during heating causes TL intensity to reach a maximum and decline at higher doses.
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722
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Wang J, Ma R, Xu F, Li L, Chen R, Hu W. Tu-P7:79 Adventitial accumulation of inflammatory cells induces the formation and extending of atherosclerotic lesions in apolipoprotein E gene knockout mice. ATHEROSCLEROSIS SUPP 2006. [DOI: 10.1016/s1567-5688(06)80787-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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723
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Curran JM, Chen R, Hunt JA. Controlling the phenotype and function of mesenchymal stem cells in vitro by adhesion to silane-modified clean glass surfaces. Biomaterials 2005; 26:7057-67. [PMID: 16023712 DOI: 10.1016/j.biomaterials.2005.05.008] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Accepted: 05/06/2005] [Indexed: 11/21/2022]
Abstract
The behaviour of human mesenchymal stem cells (hMSC) when cultured in contact with a range of silane-modified surfaces was examined to determine if changing the surface chemistry affected the early differentiation potential of mesenchymal stem cells in vitro over a 7-day period. Cells were cultured for 1 and 7 days in direct contact with glass which had been functionalized by surface treatment to provide a range of different surfaces: -CH(3), -NH(2), -SH, -OH, and -COOH modified surfaces and a clean glass reference (TAAB). Viable cell adhesion was quantified by Lactate Dehydrogenase assay, and morphology and viability was qualitatively evaluated using calcein AM, ethidium homodimer, cytoskeletal (F Actin), extra-cellular matrix (fibronectin and vitronectin) and Hoechst staining (nucleus). The expression of selected differentiation markers, Collagen II (chondrocytes), CBFA1 (bone transcription factor), Collagen I (MSC marker) and TGF-beta3 (extra-cellular matrix production) was determined using real time polymerase chain reaction. The expression of ornithine decarboxylase was evaluated as a marker of proliferation. Surfaces of the -NH(2) group demonstrated the greatest level of cell adhesion by the 7-day period, and mRNA expression profiles indicated osteogenic differentiation, increased CBFA1 and decreased Collagen II expression. Cells cultured in contact with the -COOH surfaces displayed different cell morphologies, fibronectin and vitronectin spatial distributions compared with the cells in contact with the -NH(2) surfaces, in addition to an increase in Collagen II expression, indicative of chondrogenic differentiation. The modifications to the surface chemistry of glass did affect cell behaviour, both in terms of viable cell adhesion, morphology and profiles of mRNA expression, providing the means to alter the differentiation potential of the MSCs.
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724
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Guo J, Zhao T, Prabhuram J, Chen R, Wong C. Preparation and characterization of a PtRu/C nanocatalyst for direct methanol fuel cells. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2005.05.056] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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725
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Rudney JD, Chen R. The vital status of human buccal epithelial cells and the bacteria associated with them. Arch Oral Biol 2005; 51:291-8. [PMID: 16239000 DOI: 10.1016/j.archoralbio.2005.09.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 08/30/2005] [Accepted: 09/13/2005] [Indexed: 11/17/2022]
Abstract
OBJECTIVE We have shown that buccal epithelial cells (BEC) from humans can contain a polymicrobial intracellular flora. Members of that flora can induce proinflammatory responses. However, our subjects all had healthy oral mucosa. This might reflect tolerance of bacterial invasion by live BEC. Alternatively, inflammation might not occur if invaded cells were mostly dead, and thus unable to mount a response. This study addressed that issue, by determining the vital status of BEC and the bacteria associated with them. DESIGN Initial experiments indicated that BEC were anomalously permeable to the DNA stain propidium iodide. We used that property to develop a protocol that combined the DNA stains SYTO 9 and propidium iodide (indicators of bacterial viability) with the esterase substrate calcein blue AM (an indicator of BEC viability), and Annexin V Alexa Fluor 647 conjugate (an apoptosis marker). That protocol was applied to BEC collected from 36 human subjects. RESULTS On average, 70% of BEC displayed calcein blue staining, with no binding of Annexin V, 25% showed signs of apoptosis, and 5% did not stain with calcein blue. The mean percent of BEC with live cell-associated bacteria was 29%. Collectively, 25% of total BEC displayed calcein blue staining and live (SYTO 9 stained) bacteria. Only 1% of total BEC were negative for calcein blue and associated with live bacteria. CONCLUSIONS Our findings suggest that live BEC are tolerant of bacterial invasion. This may be due to complex interactions between members of the polymicrobial flora and their host BEC.
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