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Dai G, Wang B, Huang J, Dong R, Deng S, Yu G. Occurrence and source apportionment of pharmaceuticals and personal care products in the Beiyun River of Beijing, China. CHEMOSPHERE 2015; 119:1033-1039. [PMID: 25303665 DOI: 10.1016/j.chemosphere.2014.08.056] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 08/16/2014] [Accepted: 08/23/2014] [Indexed: 05/08/2023]
Abstract
This work investigates, for the first time, the occurrence and sources of 15 pharmaceuticals and personal care products (PPCPs) in surface water of Beijing, one of most densely populated cities in the world, in three sampling events representing different seasonal flow conditions. The detection frequencies of most PPCPs were in the range of 50-100%. The median concentrations of the selected PPCPs ranged from not detected to 4200 ng L(-1) (caffeine). Generally, higher PPCP levels were observed in early spring, indicating both low flow condition and cold-water temperature might enhance their persistence. Source apportionment showed freshly discharged untreated sewage (67%) significantly contributed to the PPCP burden in the Beiyun River, which provides important information for environmental management.
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Dai G, Song X, Ma P, Liu N, Yao J. [MicroRNA-223-3p inhibits the angiogenesis of ischemic myocardial microvascular endothelial cells via modulating Rps6kb1/HIF-1α signal pathway]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 2014; 42:1039-1047. [PMID: 25623352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To explore the role of microRNA on the myocardial microvascular endothelial cells (CMECs) of ischemic heart rats in the process of angiogenesis and related regulation mechanism. METHODS Myocardial ischemic rats model was established by coronary ligation.Seven days after operation, the ischemic CMECs were cultured by the method of planting myocardium tissue and identified by immunocytochemistry to observe the biological characteristics of ischemic CMECs angiogenesis, to determine the window period of migration, proliferation, tube formation in the process of its angiogenesis. Dynamic expression changes of microRNA in the process of ischemic CMECs angiogenesis was detected using microRNA chip and further verified by real-time PCR, the core microRNA of the ischemic CMECs was defined and the predicted target genes of core microRNA were determined by bioinformatics methods and real-time PCR. At the same time, the protein expression of target gene and angiogenesis related genes of p38MAPK, PI3K,Akt,VEGF were measured by Western blot. RESULTS The CMECs of rats presented typical characteristics of microvascular endothelial cells, and factor VIII, CD31 related antigens were all positively stained by immunocytochemical analysis. The migration window period was on the first day, and the tube formation window period was on the second day of both control and ischemic groups, while the proliferation window period was on the third day for the normal group, and the sixth day for ischemic group. According to the expressional difference and their relationship with angiogenesis, miRNA-223-3p was ultimately determined as the core microRNA in the process of ischemic CMECs angiogenesis, real-time PCR verified this hypothesis. Bioinformatics methods predicted that Rps6kb1 is the target genes of miRNA-223-3p, the pathway analysis showed that Rps6kb1 could regulate angiogenesis via HIF-1α signal pathway. Moreover, the mRNA and protein expression of VEGF, p38MAPK, PI3K,Akt, which were the downstream molecules of Rps6kb1/HIF-1α signal pathway, were also significantly downregulated in ischemic CMECs from migration and proliferation stage. CONCLUSION Our results show that the miRNA-223-3p is the core microRNA of ischemic CMECs angiogenesis. MiRNA-223-3p could regulate Rps6kb1/HIF-1α signal pathway, inhibit the process of migration and proliferation of ischemic CMECs angiogenesis. MiRNA-223-3p is thus likely to be a core target for enhancing angiogenesis of ischemic heart disease.
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Shangguan JB, Li ZB, Li QH, Dai G, Ning YF. Screening and characterization of new microsatellite markers in Fenneropenaeus penicillatus. GENETICS AND MOLECULAR RESEARCH 2014; 13:6079-82. [PMID: 25117365 DOI: 10.4238/2014.august.7.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fenneropenaeus penicillatus, with high protein and low fat, is a commercially important aquatic product in China. Microsatellite loci were developed according to the protocol of fast isolation by amplified fragment length polymorphism of sequences containing repeats. Eight new polymorphic microsatellite markers for F. penicillatus were identified, and 32 wild individuals were used to evaluate the degree of polymorphism of these markers. The polymorphism information content ranged from 0.2703 to 0.7598, and the number of alleles per locus varied from 3 to 6. The observed and expected heterozygosities were 0.1613-0.5556 and 0.2347-0.7387, respectively. No significant deviations from Hardy-Weinberg equilibrium (P > 0.00625) were detected. These polymorphic microsatellite loci will be useful to study the genetic diversity and population structure of F. penicillatus.
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Zheng P, Liu J, Mai S, Yuan Y, Wang Y, Dai G. Regulation of signal transducer and activator of transcription 3 and apoptotic pathways by betaine attenuates isoproterenol-induced acute myocardial injury in rats. Hum Exp Toxicol 2014; 34:538-47. [PMID: 25080425 DOI: 10.1177/0960327114543936] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The present study was designed to investigate the cardioprotective effects of betaine on acute myocardial ischemia induced experimentally in rats focusing on regulation of signal transducer and activator of transcription 3 (STAT3) and apoptotic pathways as the potential mechanism underlying the drug effect. Male Sprague Dawley rats were treated with betaine (100, 200, and 400 mg/kg) orally for 40 days. Acute myocardial ischemic injury was induced in rats by subcutaneous injection of isoproterenol (85 mg/kg), for two consecutive days. Serum cardiac marker enzyme, histopathological variables and expression of protein levels were analyzed. Oral administration of betaine (200 and 400 mg/kg) significantly reduced the level of cardiac marker enzyme in the serum and prevented left ventricular remodeling. Western blot analysis showed that isoproterenol-induced phosphorylation of STAT3 was maintained or further enhanced by betaine treatment in myocardium. Furthermore, betaine (200 and 400 mg/kg) treatment increased the ventricular expression of Bcl-2 and reduced the level of Bax, therefore causing a significant increase in the ratio of Bcl-2/Bax. The protective role of betaine on myocardial damage was further confirmed by histopathological examination. In summary, our results showed that betaine pretreatment attenuated isoproterenol-induced acute myocardial ischemia via the regulation of STAT3 and apoptotic pathways.
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Dai G, Huang J, Chen W, Wang B, Yu G, Deng S. Major pharmaceuticals and personal care products (PPCPs) in wastewater treatment plant and receiving water in Beijing, China, and associated ecological risks. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2014; 92:655-61. [PMID: 24619361 DOI: 10.1007/s00128-014-1247-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 03/03/2014] [Indexed: 05/18/2023]
Abstract
The occurrence of 15 pharmaceuticals and personal care products in the influent and effluent from the wastewater treatment plant (WWTP) and its receiving water in Beijing, China were determined. Results from the present study confirmed that caffeine, N,N-diethyl-m-toluamide and chloramphenicol were removed at a high rate (>70 % efficiency). In contrast, removal efficiency of the other 12 compounds was quite poor (ranged from -40 % to 58 %). Some compounds in the receiving river were present at higher concentrations compared to those in the WWTP effluent, indicating that sources other than treated effluents are present. The risk to the aquatic environment was estimated by a ratio of measured environmental concentration and predicted no-effect concentration. For those compounds found in the effluent and surface water, mefenamic acid, trimethoprim and gemfibrozil may pose a medium risk to aquatic environment.
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Li QH, Li ZB, Dai G, Chen XJ, Chen LN, Cao YY, Shangguan JB, Ning YF. Characterization of new microsatellite markers of Siganus fuscescens (Siganidae). GENETICS AND MOLECULAR RESEARCH 2013; 12:2751-4. [PMID: 23979899 DOI: 10.4238/2013.july.30.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Siganus fuscescens, which is a small commercially important marine fish, is wildly distributed in shallow waters throughout the tropical and subtropical Indo-Pacific and Eastern Mediterranean regions. It is part of a group known as rabbitfish. Fifteen new polymorphic microsatellite markers for S. fuscescens were identified, and 32 wild individuals were used to evaluate the degree of polymorphism of these markers. The number of alleles per locus ranged from 2 to 12, and the polymorphism information content ranged from 0.210 to 0.849. The observed and expected heterozygosities were 0.142-0.808 and 0.225-0.853, respectively. Although significant deviations from Hardy-Weinberg equilibrium were detected at 2 loci (Sf1-37-2 and Sf1-47), no significant deviations were detected at the other 13 loci. These microsatellite markers will provide a useful tool for studies on genetic diversity and differentiation of S. fuscescens.
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Zhang L, Dai G. Blank Design and Fiber Orientation Distribution During Compression Molding of GMT. INT POLYM PROC 2013. [DOI: 10.3139/217.1541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Glass mat thermoplastics (GMT) have the superior property/price ratio, they can be used in many industrial aspects. In this paper, through a 100mm-deep mold, the glass mat distribution, fiber orientation and mechanical properties of the part were studied under different blank designs. In conclusion, (1) Blank design has effect on the mat distribution and fiber orientation, and finally on the mechanical properties of the part. To a part, there is an optimum blank design, which will not greatly decrease the mechanical properties of the sheets in the final part. (2) In compression molding, interlaminar slippage, blank ejection and resin solidification result in mat distribution and fiber orientation.
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Cao YY, Li ZB, Li QH, Chen XJ, Chen L, Dai G. Characterization of eight novel microsatellite markers in the green-lipped mussel Perna viridis (Mytilidae). GENETICS AND MOLECULAR RESEARCH 2013; 12:344-7. [PMID: 23420359 DOI: 10.4238/2013.february.7.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The green lipped mussel, also known as the Asian green mussel (Perna viridis) is a fast reproducing and valuable food source, but it is also considered an invasive species and can clog and damage pipes and marine equipment. Eight novel polymorphic microsatellite loci for P. viridis were isolated and characterized. Microsatellite polymorphism was evaluated in 30 individuals collected from Xiamen, China. The number of alleles per locus and the polymorphism information content ranged from 2 to 5 and from 0.3092 to 0.7031, respectively. The observed and expected heterozygosities were 0.1538-0.8400 and 0.1448-0.6833, respectively. The loci identified in this study could provide a useful tool for the genetic population structure analysis of P. viridis.
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Dai G, Liu X, Liang G, Gong W, Tao L, Cheng D. Evaluating the sediment-water exchange of hexachlorocyclohexanes (HCHs) in a major lake in North China. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2013; 15:423-432. [PMID: 25208707 DOI: 10.1039/c2em30794d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A large-scale sampling program was conducted to simultaneously collect surface water, overlying water, pore water and sediment samples at monthly intervals from March to December 2010 from the Baiyangdian Lake, North China to assess the distribution of hexachlorocyclohexanes (HCHs) and determine the net direction of sediment-water exchange. Total HCHs concentrations ranged from 6.30-53.90 ng L (-1), 16.59-148.48 ng L(-1), 247.93-459.07 ng L (-1) and 3.60-12.50 ng g(-1) in surface water, overlying water, pore water and sediments, respectively, which was at the intermediate level compared to those of other areas in China. Seasonal variations of HCHs were featured by lower concentrations in April, July and November due to the dilution of HCHs caused by a great deal of fresh water being allocated to the Baiyangdian Lake in these months. Sediment-water fugacity ratios of the HCH isomers were used to predict the direction of the sediment-water exchange of these isomers. The sediment-surface water and sediment-overlying water fugacity ratios of HCH isomers averaged 11.4 and 3.0, which is significantly greater than the equilibrium status (1.0), suggesting that the net flux directions were from the sediment to water and the sediment acted as a secondary source to the water. Sediment-pore water fugacity ratios indicated near equilibrium or escape from pore water to sediment, depending on the isomer and sampling time. The difference of HCH concentrations between sediment and water samples were found to be an important factor affecting the diffusion of HCH from the sediment to water.
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Hua R, Shi J, Wang X, Yang J, Zheng P, Cheng H, Li M, Dai G, An Y. Analysis of the causes and types of traumatic spinal cord injury based on 561 cases in China from 2001 to 2010. Spinal Cord 2012. [PMID: 23184031 DOI: 10.1038/sc.2012.133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES A remarkable increase in traumatic spinal cord injury (TSCI) morbidity has occurred in China from 2001 to 2010 due to rapid industrial and economic development; this increase seriously threatens public health. The current study investigated the major causes and severity of TSCI in 561 hospitalized TSCI patients who came from all over China to the General Hospital of Chinese People's Armed Police Forces. METHODS Information (including each patient's age, gender, time and cause of injury and severity of spinal cord injury (SCI, complete or incomplete)) regarding 561 hospitalized TSCI patients whose injuries occurred between 2001 and 2010 was retrospectively analyzed. RESULTS Among the 561 patients, the youngest was 9 months old and the oldest was 67 years old; the average patient age was 34.74 ± 12.24 years. The sex ratio was 4.1:1 (male:female). The injuries were primarily caused by transportation accidents (51.2%), falling from a height (23.9%), tamping (8.6%), stumbling (8.0%), stabbing (3.0%) and crushing (1.8%). Although no statistically significant associations were observed between the different injury causes and severity of the injury, a statistically significant association was observed between the different injury causes and levels of the lesion. CONCLUSION Transportation accidents, falling from a height, tamping, stumbling, stabbing and crushing are the most common causes of TSCI. No statistically significant relationships were observed between certain injury causes and either complete or incomplete injury. However, different injury causes usually led to different levels of the lesion. No statistical differences were observed between the levels of the lesion and either complete or incomplete injury.
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Hou D, Dai G, Wang J, Fan H, Zhang L, Luan Z. Preparation and characterization of PVDF/nonwoven fabric flat-sheet composite membranes for desalination through direct contact membrane distillation. Sep Purif Technol 2012. [DOI: 10.1016/j.seppur.2012.08.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Gong W, Liu X, He H, Wang L, Dai G. Quantitatively modeling soil-water distribution coefficients of three antibiotics using soil physicochemical properties. CHEMOSPHERE 2012; 89:825-831. [PMID: 22658476 DOI: 10.1016/j.chemosphere.2012.04.064] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 04/27/2012] [Accepted: 04/28/2012] [Indexed: 06/01/2023]
Abstract
Using 14 parameters featuring soil physicochemical properties and the partial least squares (PLSs) regression method, three quantitative models were respectively developed for the soil-water distribution coefficients (logK(d)) of oxytetracycline (OTC), sulfamethazine (SMZ) and norfloxacin (NOR) in 23 Chinese natural soil samples from cultivated lands in 19 provinces of China. The cross-validated correlation coefficients (Q(cum)(2)) of three models are 0.866, 0.765 and 0.868, and the standard deviations (SDs) are 0.16, 0.21 and 0.15 respectively. The high Q(cum)(2) and low SD values indicate that three models have high robustness and precise predictability. Six parameters including pH, clay content, free Fe oxides (DCB-Fe), free Al oxides (DCB-Al), Ca content and Al content are greatly significant in the OTC model, three ones including pH, clay content and DCB-Fe are greatly significant in the SMZ model, and five ones including pH, clay content, DCB-Fe, Ca content and organic matter (OM) are greatly significant in the NOR model. The high VIP values of pH (1.17-1.24), clay content (0.81-1.10) and DCB-Fe (0.90-0.99) show that the three sorts of soil physicochemical properties play dominant roles in governing the partition balance between soil and water of three antibiotics.
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Xie K, Jia L, Xu D, Guo H, Xie X, Huang Y, Chen X, Bao W, Dai G, Wang J. Simultaneous Determination of Amoxicillin and Ampicillin in Eggs by Reversed-Phase High-Performance Liquid Chromatography with Fluorescence Detection using Pre-Column Derivatization. J Chromatogr Sci 2012; 50:620-4. [DOI: 10.1093/chromsci/bms052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Li J, Dai G, Cheng YB, Qi X, Geng MY. Polysialylation promotes neural cell adhesion molecule-mediated cell migration in a fibroblast growth factor receptor-dependent manner, but independent of adhesion capability. Glycobiology 2011; 21:1010-8. [DOI: 10.1093/glycob/cwr020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Dai G, Liu X, Liang G, Han X, Shi L, Cheng D, Gong W. Distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface water and sediments from Baiyangdian Lake in North China. J Environ Sci (China) 2011; 23:1640-1649. [PMID: 22432259 DOI: 10.1016/s1001-0742(10)60633-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Persistent organochlorine compounds, including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and polychlorinated biphenyls (PCBs) were analyzed in surface water and sediments from Baiyangdian Lake, North China. Total concentrations of HCHs, DDTs and PCBs in surface water were in the range of 3.13-10.60, 4.05-20.59 and 19.46-131.62 ng/L, respectively, and total concentrations of HCHs, DDTs and PCBs in sediments were 1.75-5.70, 0.91-6.48 and 5.96-29.61 ng/g dry weight, respectively. Among the groups of HCHs (sum of alpha-HCH, beta-HCH, gamma-HCH and delta-HCH) and DDTs (sum of DDT, DDD and DDE), the predominance of beta-HCH, DDE and DDD in water and sediment samples was clearly observed. This observation suggested that beta-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD. For PCBs, penta-, hexa- and hepta-chlorinated congeners were the most abundant compounds in the both phases. Furthermore, the partitioning of chlorinated compounds between sediment and water was investigated to understand their transport and fates in aquatic ecosystems. The results indicated that average logs of organic carbon-normalized sediment-water partition coefficients (logK'(oc)) for OCPs varied between 3.20 and 5.53, and for PCBs, logK'(oc) values ranged from 3.19 to 5.57. The observed logK'(oc) was lower than their equilibrium logK(oc) predicted from linear model, which may be attributed to the solubility enhancement effect of colloidal matter in water phase and the disequilibrium between sediment and water.
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Liao XX, Lin JY, Wei HY, Li H, Li X, Liu R, Hu CL, Huang GQ, Dai G. e0225 Hydrogen sulfide inhabits neurons apoptosis in rats after cardiopulmonary resuscitation. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Freudenberger T, Dai G, Mayer P, Heim HK, Fischer J. P359 LENTIVIRAL OVEREXPRESSION OF HYALURONIC ACID SYNTHASES 1 AND 2 RESTORES ESTRADIOL-MEDIATED INHIBITION OF PDGF-INDUCED PROLIFERATION IN VASCULAR SMOOTH MUSCLE CELLS. ATHEROSCLEROSIS SUPP 2010. [DOI: 10.1016/s1567-5688(10)70426-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kim YR, Tejima E, Huang S, Atochin DN, Dai G, Lo EH, Huang PL, Bogdanov A, Rosen BR. In vivo quantification of transvascular water exchange during the acute phase of permanent stroke. Magn Reson Med 2009; 60:813-21. [PMID: 18816832 DOI: 10.1002/mrm.21708] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mechanisms that underlie early ischemic damages to the blood-brain-barrier (BBB) are not well understood. This study presents a novel magnetic resonance imaging (MRI) technique using a widely available pulse sequence and a long-circulating intravascular contrast agent to quantify water movements across the BBB at early stages of stroke progression. We characterized the integrity of the BBB by measuring the flip angle dependence of the water exchange-affected MRI signal intensity, to generate an efficient quantitative index of vascular permeability (WEI, or water exchange index). We performed in vivo MRI experiments to measure the transvascular WEI immediately after the permanent filament occlusion of the middle cerebral artery of mice (n = 5), in which we monitored changes in blood volume (V(b)), apparent diffusion coefficient (ADC), and intra-/extravascular WEI for 4 hours. Statistically significant elevations (P < 0.05) of WEI in the ischemic tissue were observed as early as 1 hour after ischemic onset. Initial reduction of the apparent blood volume (V(app)) in the infarct cortex was followed by a continuous increase of V(app) over time. Although the measured ADC in the ipsilesional cortex continuously decreased, the abnormally high intra-/extravascular WEI remained constant at a significantly elevated level, indicating apparent BBB injury at this early stage of stroke.
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Sazaki G, Dai G, Van Driessche A, Yoshizaki I, Matsui T, Otalora F, Tsukamoto K, Nakajima K. Single-molecule visualization on a protein crystal surface. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308092076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Wedeen VJ, Wang RP, Schmahmann JD, Benner T, Tseng WYI, Dai G, Pandya DN, Hagmann P, D'Arceuil H, de Crespigny AJ. Diffusion spectrum magnetic resonance imaging (DSI) tractography of crossing fibers. Neuroimage 2008; 41:1267-77. [PMID: 18495497 DOI: 10.1016/j.neuroimage.2008.03.036] [Citation(s) in RCA: 678] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 03/14/2008] [Accepted: 03/17/2008] [Indexed: 11/30/2022] Open
Abstract
MRI tractography is the mapping of neural fiber pathways based on diffusion MRI of tissue diffusion anisotropy. Tractography based on diffusion tensor imaging (DTI) cannot directly image multiple fiber orientations within a single voxel. To address this limitation, diffusion spectrum MRI (DSI) and related methods were developed to image complex distributions of intravoxel fiber orientation. Here we demonstrate that tractography based on DSI has the capacity to image crossing fibers in neural tissue. DSI was performed in formalin-fixed brains of adult macaque and in the brains of healthy human subjects. Fiber tract solutions were constructed by a streamline procedure, following directions of maximum diffusion at every point, and analyzed in an interactive visualization environment (TrackVis). We report that DSI tractography accurately shows the known anatomic fiber crossings in optic chiasm, centrum semiovale, and brainstem; fiber intersections in gray matter, including cerebellar folia and the caudate nucleus; and radial fiber architecture in cerebral cortex. In contrast, none of these examples of fiber crossing and complex structure was identified by DTI analysis of the same data sets. These findings indicate that DSI tractography is able to image crossing fibers in neural tissue, an essential step toward non-invasive imaging of connectional neuroanatomy.
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Guo X, Lu X, Tong S, Dai G. Influence of environment and substrate quality on the decomposition of wetland plant root in the Sanjiang Plain, Northeast China. J Environ Sci (China) 2008; 20:1445-1452. [PMID: 19209630 DOI: 10.1016/s1001-0742(08)62547-4] [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] [Indexed: 05/27/2023]
Abstract
The litterbag method was used to study the decomposition of wetland plant root in three wetlands along a water level gradient in the Sanjiang Plain, Northeast China. These wetlands are Calamagrostis angustifolia (C.aa), Carex meyeriana (C.ma) and Carex lasiocarpa (C.la). The objective of our study is to evaluate the influence of environment and substrate quality on decomposition rates in the three wetlands. Calico material was used as a standard substrate to evaluate environmental influences. Roots native to each wetland were used to evaluate decomposition dynamics and substrate quality influences. Calico mass loss was statistically different among the three wetlands in the upper soil profile (0-10 cm) and in the lower depth range (10-20 cm). Hydrology, temperature and pH all influence calico decomposition rates in different ways at different depths of the soil profiles. The decomposition rates of native roots declined differentially with the increase of depth in the soil profiles. The mass loss of native roots showed a statistical decrease among the three wetlands in the upper soil profile (0-10 cm) and in the lower depth range (10-20 cm) as C.ma wetland > C.aa wetland > C.la wetland. Both the C:P ratio and N:P ratio were positively interrelated with decomposition rates. Decomposition rates were negatively related to initial P concentration in all three wetlands, indicating that P concentration seems to be an important factor controlling the litter loss.
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Shen WG, Peng WX, Shao Y, Xu JF, Dai G, Zhang Y, Pan FY, Li CJ. Localization and activity of calmodulin is involved in cell–cell adhesion of tumor cells and endothelial cells in response to hypoxic stress. Cell Biol Toxicol 2007; 23:323-35. [PMID: 17351827 DOI: 10.1007/s10565-006-0157-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2006] [Accepted: 11/29/2006] [Indexed: 01/11/2023]
Abstract
Adhesion of tumor cells to endothelial cells is known to be involved in the hematogenous metastasis of cancer, which is regulated by hypoxia. Hypoxia is able to induce a significant increase in free intracellular Ca2+ levels in both tumor cells and endothelial cells. Here, we investigate the regulatory effects of calmodulin (CaM), an intracellular calcium mediator, on tumor cell-endothelial cell adhesion under hypoxic conditions. Hypoxia facilitates HeLa cell-ECV304 endothelial cell adhesion, and results in actin cytoskeleton rearrangement in both endothelial cells and tumor cells. Suppression of CaM activation by CaM inhibitor W-7 disrupts actin cytoskeleton organization and CaM distribution in the cell-cell contact region, and thus inhibits cell-cell adhesion. CaM inhibitor also downregulates hypoxia-induced HIF-1-dependent gene expression. These results suggest that the Ca2+ -CaM signaling pathway might be involved in tumor cell-endothelial cell adhesion, and that co-localization of CaM and actin at cell-cell contact regions might be essential for this process under hypoxic stress.
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Rider V, Potapova T, Dai G, Soares MJ. Stimulation of a rat uterine stromal cell line in culture reveals a molecular switch for endocrine-dependent differentiation. J Endocrinol 2005; 184:119-27. [PMID: 15642789 DOI: 10.1677/joe.1.05957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Differentiation of uterine stromal cells is critical for the establishment of pregnancy. This study had two purposes: (i) to validate the use of the UIII rat uterine stromal cell model for investigating mechanisms underlying decidual cell differentiation, and (ii) to use this cell model to identify a molecular switch for cellular entry into the decidual cell differentiation pathway. Quiescent rat uterine stromal cells were transfected with a 500 bp segment of the decidual prolactin-related protein (dPRP) promoter ligated to a luciferase reporter gene. Cells were incubated in low-serum medium, or in low-serum medium containing progesterone (1 microM), estradiol 17-beta (10 nM), cholera toxin (10 ng/ml) and interleukin-11 (10 ng/ml). Protein extracts were collected 48 h later and luciferase was measured in the cellular lysates. Cholera toxin and interleukin-11 stimulated luciferase expression (P< 0.05) and addition of sex steroids further increased (P< 0.05) dPRP promoter activity. Stromal cells did not proliferate (P< 0.05) under differentiation conditions. Deletion analysis of the dPRP promoter revealed maximal luciferase expression between -250 and -500 bp relative to the transcription start site. Comparison of cyclin E/Cdk2 activity between proliferating and differentiating cells showed a 3-fold increase (P< 0.05) at 12 h in differentiating cells. The results suggest that cyclin E/Cdk2 serves as a molecular switch for uterine stromal cell entry into the decidual cell differentiation pathway.
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Lehrer SB, Reish R, Fernandes J, Gaudry P, Dai G, Reese G. Enhancement of murine IgE antibody detection by IgG removal. J Immunol Methods 2004; 284:1-6. [PMID: 14736411 DOI: 10.1016/j.jim.2003.08.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE Although animal models for the study of allergic reactions are desirable, the use of mice has been hindered by the lack of sufficiently sensitive in vitro immunoglobulin epsilon (IgE) antibody assays. The aim of this study was to enhance IgE antibody measurements by immunoglobulin gamma (IgG) depletion. METHODS Seven- to eight-week-old female mice of four strains (C3H/HeJ, CBA/J, C57Bl/6J, and Balb/c) were immunized (20 mice/group) with shrimp or peanut extracts using Al(OH)(3) as adjuvant. Following immunization, animals were sacrificed by exsanguination and the sera of each group pooled. Initial measurements of IgE antibody levels by enzyme-linked immunosorbent assay (ELISA) were relatively low; IgG and IgE reactivity patterns by immunoblot were similar. Thus, sera from shrimp or peanut immunized mice were depleted of IgG (absorbed 3-6 times with immobilized protein G) and then tested for IgE antibody to shrimp or peanut allergen. RESULTS A 3- to 5-fold increase in IgE antibody reactivity as measured by ELISA was demonstrated when >80-90% of the IgG was removed. This increase in detection of allergen-specific IgE occurred in sera from all mouse strains and to all allergens tested. In addition, reactivity of IgE antibodies to peanut or shrimp allergens by immunoblot increased visually approximately 4- to 10-fold. CONCLUSIONS These studies indicate that allergen-specific IgG antibodies, which may be in more than 100-fold excess to IgE antibodies, interferes with detection of allergen-specific IgE, probably by competitive binding to allergenic epitopes. Substantial depletion of IgG antibodies (>80%) result in a significant increase in the sensitivity of the antibody measurements.
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Lehrer S, Fernandes J, Reisch R, Gaudry P, Dai G, Reese G. Murine IgE and IgG antibody responses to peanuts and shrimp allergens: Major food allergens in man. J Allergy Clin Immunol 2003. [DOI: 10.1016/s0091-6749(03)80875-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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