237 results on '"Jun-Jie Yin"'
Search Results
152. Disruption of microfilaments by cytochalasin B decreases accumulation of cisplatin in human epidermal carcinoma and liver carcinoma cell lines
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Jun-Jie Yin, Susan H. Garfield, Michael M. Gottesman, Barbara J. Taylor, Stephen M. Winkovitch, Ding-Wu Shen, Adorjan Aszalos, and Xing-Jie Liang
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Cancer Research ,Pathology ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,Cell Membrane Permeability ,Skin Neoplasms ,Cytochalasin B ,Membrane Fluidity ,Biology ,Toxicology ,Microfilament ,KB Cells ,Membrane Potentials ,chemistry.chemical_compound ,Cell Line, Tumor ,medicine ,Humans ,Pharmacology (medical) ,Cytochalasin ,Pharmacology ,Cisplatin ,Epidermis (botany) ,Carcinoma ,Liver Neoplasms ,Biological Transport ,In vitro ,Actin Cytoskeleton ,Oncology ,chemistry ,Cell culture ,Drug Resistance, Neoplasm ,Cancer cell ,Cancer research ,Cell Division ,medicine.drug - Abstract
Although cisplatin is a frequently used cancer chemotherapeutic drug, its effectiveness is hindered by the development of resistance in cancer cells. In order to understand the reason(s) for this resistance, the mechanism of uptake of cisplatin into cells must be characterized. While several previous studies showed structural differences between cisplatin-sensitive and resistant cells, the influence of microfilaments, known to affect transport of molecules into cells, and the influence of certain biophysical characteristics of the plasma membrane needed clarification.We show that resistant human epidermal carcinoma (KB-CP20) and liver carcinoma (BEL-7404-CP20) cells become relatively more resistant if their already weak microfilaments are degraded by cytochalasin B treatment (.5-2 microM). The sensitive counterparts of these cells with intact microfilaments are not significantly affected by this treatment. We also show that the "fluidity" of the plasma membrane and the membrane potential of the sensitive and resistant cells studied do not appear to influence the uptake of cisplatin into the cells.Our results suggest that the status of the microfilament system influences the mechanism of uptake of cisplatin into cells. more...
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- 2007
153. Photodecomposition of vitamin A and photobiological implications for the skin
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Peter P, Fu, Qingsu, Xia, Jun Jie, Yin, Shu-Hui, Cherng, Jian, Yan, Nan, Mei, Tao, Chen, Mary D, Boudreau, Paul C, Howard, and Wayne G, Wamer
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Retinoids ,Photochemistry ,Ultraviolet Rays ,Humans ,Spectrophotometry, Ultraviolet ,In Vitro Techniques ,Vitamin A ,Models, Biological ,Photobiology ,Skin - Abstract
Vitamin A (retinol), an essential human nutrient, plays an important role in cellular differentiation, regulation of epidermal cell growth and normal cell maintenance. In addition to these physiological roles, vitamin A has a rich photochemistry. Photoisomerization of vitamin A, involved in signal transduction for vision, has been extensively investigated. The biological effects of light-induced degradation of vitamin A and formation of reactive species are less understood and may be important for light-exposed tissues, such as the skin. Photochemical studies have demonstrated that excitation of retinol or its esters with UV light generates a number of reactive species including singlet oxygen and superoxide radical anion. These reactive oxygen species have been shown to damage a number of cellular targets, including lipids and DNA. Consistent with the potential for damaging DNA, retinyl palmitate has been shown to be photomutagenic in an in vitro test system. The results of mechanistic studies were consistent with mutagenesis through oxidative damage. Vitamin A in the skin resides in a complex environment that in many ways is very different from the chemical environment in solution and in in vitro test systems. Relevant clinical studies or studies in animal models are therefore needed to establish whether the pro-oxidant activity of photoexcited vitamin A is observed in vivo, and to assess the related risks. more...
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- 2007
154. Fatty acids in tea shoots (Camellia sinensis (L.) O. Kuntze) and their effects on the growth of retinal RF/6A endothelial cell lines
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Yao-kang Xiong, Shengrong Shen, Haining Yu, Ping Chen, and Jun-Jie Yin
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Antioxidant ,medicine.medical_treatment ,Linoleic acid ,Palmitic Acid ,Retina ,Cell Line ,Linoleic Acid ,chemistry.chemical_compound ,Oxygen Consumption ,medicine ,Cell Adhesion ,Animals ,MTT assay ,Camellia sinensis ,Theaceae ,Cell Proliferation ,biology ,Tea ,Fatty Acids ,Electron Spin Resonance Spectroscopy ,food and beverages ,Endothelial Cells ,alpha-Linolenic Acid ,Free Radical Scavengers ,biology.organism_classification ,Macaca mulatta ,Biochemistry ,chemistry ,Cell culture ,Apoptosis ,Shoot ,Food Science ,Biotechnology - Abstract
Chemo-protective effects of tea on ocular diseases were recorded in Chinese pharmacopoeia about 2000 years ago by eating tea. In the present study, contents of fatty acids (FAs) in tea shoots were determined by capillary GC; and the growth of RF/6A cells was also investigated by exposure to various representative FAs existing in tea shoots with pathologically relevant concentrations (40-500 microM) by ameliorated MTT assay and flow cytometry. Electron spin resonance (ESR) was used to measure oxygen consumption and investigate the free radical scavenging ability of linoleic acid (LA). Results showed that the most abundant long chain FAs were palmitic, linoleic, and alpha-linolenic acid in tea shoots; some RF/6A cells became suspended in culture medium treated by a high dose of both saturated and unsaturated FAs, but no apoptosis was observed. Moreover, it seemed that those FAs with different structure had various effects on the cell proliferation at their relatively low concentrations, LA expressed antioxidant activity in this study, which might be an important mechanism on the protection of eyes. more...
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- 2007
155. Comparative effects of flavonoids on oxidant scavenging and ischemia-reperfusion injury in cardiomyocytes
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Jun-Jie Yin, Lance B. Becker, Yimin Qin, Juan Li, Zuo-Hui Shao, Chun-Su Yuan, Sangeeta R. Mehendale, Wei-Tien Chang, Chong-Zhi Wang, Chiang Ting Chien, Terry L. Vanden Hoek, and Wen-Jone Chen
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Cell Survival ,Ischemia ,Chick Embryo ,Pharmacology ,Article ,chemistry.chemical_compound ,Wogonin ,Picrates ,Superoxides ,medicine ,Animals ,Myocytes, Cardiac ,Procyanidin B2 ,Cells, Cultured ,chemistry.chemical_classification ,Flavonoids ,Reactive oxygen species ,Hydroxyl Radical ,Biphenyl Compounds ,Electron Spin Resonance Spectroscopy ,Catechin ,Free Radical Scavengers ,medicine.disease ,Oxidants ,Baicalein ,Hydrazines ,chemistry ,Biochemistry ,Reperfusion Injury ,Reperfusion injury ,Baicalin - Abstract
Since flavonoids scavenge reactive oxygen species, they may potentially protect against ischemia/reperfusion injury. This study compared the scavenging capacity of specific flavonoids towards different reactive oxygen species. Whether the differential oxidant scavenging capacity correlated with their protective efficacy in ischemia/reperfusion injury of cardiomyocytes was determined. The free radical scavenging capacity of five flavonoids (wogonin, baicalin, baicalein, catechin and procyanidin B2) was analyzed using electron spin resonance spectrometry for 3 radicals: 1,1-diphenyl-2picrylhydrazyl (DPPH), superoxide and hydroxyl radical. A well-established chick cardiomyocyte model of ischemia (1 h)/reperfusion (3 h) was used to evaluate flavonoid-induced protection against ischemia/reperfusion injury in chronic treatment (pretreated 72 h and treated through ischemia/reperfusion) and acute treatment protocols (during ischemia/reperfusion or only at reperfusion). The cell viability was assessed by propidium iodide. The DPPH scavenging was most significant with catechin, followed by procyanidin B2, baicalein, baicalin, and wogonin. The superoxide scavenging was, similarly, most significant with catechin, followed by baicalein, procyanidin B2, and baicalin. For hydroxyl radical, only baicalein showed a significant scavenging capacity (> 50% reduction in ESR signal). For the cardiomyocyte studies, all flavonoids but wogonin showed protection against ischemia/reperfusion injury in the chronic treatment protocol. When flavonoids were administered only during ischemia/reperfusion, baicalein, procyanidin B2, and catechin significantly reduced cell death. If flavonoids were administered just at reperfusion, only baicalein and procyanidin B2 had protective effects, and the efficacy was less. Flavonoids possess specific but differential radical scavenging capacity, which, in conjunction with the timing of treatment, affects their protective efficacy in cardiomyocytes exposed to ischemia/reperfusion. more...
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- 2006
156. Antioxidative Activity of Conjugated Linoleic Acid Determined by ESR
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Martin P.Yurawecz, Jun-Jie Yin, Liangping Yu, John Kramer, Liangli Yu, John Roach, and Magdi Mossoba
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- 2006
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157. Effects of conjugated linoleic acid (CLA) isomers on oxygen diffusion-concentration products in liposomes and phospholipid solutions
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John K. G. Kramer, Liangli Yu, Magdi M. Mossoba, Jun-Jie Yin, A R Eynard, and Martin P. Yurawecz
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Cell Membrane Permeability ,Radical ,Conjugated linoleic acid ,Linoleic acid ,Lipid Bilayers ,Phospholipid ,Peroxide ,Phase Transition ,Lipid peroxidation ,Diffusion ,chemistry.chemical_compound ,Isomerism ,Organic chemistry ,Linoleic Acids, Conjugated ,Unsaturated fatty acid ,Phospholipids ,Liposome ,Chromatography ,food and beverages ,General Chemistry ,Oxygen ,Solutions ,chemistry ,Liposomes ,Phosphatidylcholines ,lipids (amino acids, peptides, and proteins) ,Lipid Peroxidation ,General Agricultural and Biological Sciences - Abstract
Conjugated linoleic acids (CLAs) are a group of octadecadienoic acids (18:2) that are naturally present in food products and may have beneficial health effects. Liposomes and ethanol solutions were prepared by mixing synthetic phosphatidylcholines (PCs) with c9,t11-CLA, t10,c12-CLA, and linoleic acid (LA) in the sn-2 position into natural PCs from soybean, egg yolk, rat brain, and rat heart at 5 mol %. The oxygen diffusion-concentration products were measured using electron spin resonance spin-label oximetry methods. Individual synthetic PCs, the phospholipid matrix, and the tested lipid systems all exhibited influence on oxygen diffusion-concentration products during lipid peroxidation. Incorporating 5 mol % PC(c9,t11-CLA) into soy and egg yolk PC increased oxygen consumption in liposome suspensions while it was decreased in rat heart and brain PCs. On the other hand, PC(t10,c12-CLA) increased oxygen consumption in mixtures with egg yolk and rat heart PC but decreased it in soybean and rat brain PC. By comparison, PC(LA) decreased oxygen consumption in every case. In ethanol solutions, all of the synthetic PCs suppressed the capacity to generate peroxide radicals in the order of LA > c9,t11-CLA > t10,c12-CLA. In addition, PCs containing individual CLA isomers and LA differed in their capacities to react with and quench DPPH radicals in both ethanol solution and liposome, suggesting differences between CLA isomers and LA in DPPH radical-fatty acid interactions. Incorporation of CLA isomers and LA into dimyristyl-PC reduced the phase transition temperature from 23.6 to 23.1 and 23.3 degrees C, respectively. The results of this study provide evidence that the behavior of CLA isomers differs in the microenvironment of membranes possibly due to structural differences that affect the permeability of membranes to oxygen and lipid peroxidation. more...
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- 2006
158. Effects of postharvest treatment and heat stress on availability of wheat antioxidants
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Jun-Jie Yin, Lan Su, Liangli Lucy Yu, Zhihong Cheng, Kequan Zhou, Marla Luther, and Jeffrey C. Moore
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Antioxidant ,ABTS ,Hot Temperature ,Bran ,DPPH ,Food Handling ,medicine.medical_treatment ,digestive, oral, and skin physiology ,food and beverages ,Agriculture ,General Chemistry ,Phenolic acid ,Antioxidants ,chemistry.chemical_compound ,chemistry ,Dry weight ,Botany ,Seeds ,medicine ,Postharvest ,Hydroxybenzoates ,Composition (visual arts) ,Food science ,General Agricultural and Biological Sciences ,Triticum - Abstract
This research evaluated the effects of postharvest treatment and heat stress on the availability of wheat antioxidants using Ankor and Trego wheat varieties. The grain, bran, and 40-mesh bran samples of both Ankor and Trego wheat were kept at 25, 60, and 100 degrees C for 9 days. Samples taken at day 0, 1, 2, 3, 5, and 9 were extracted with pure ethanol and examined for antioxidant properties including the scavenging activity against peroxyl (ORAC), cation ABTS, and 2,2-diphenyl-1-picryhydrazyl (DPPH.) radicals, as well as total phenolic content (TPC) and phenolic acid composition. Both heat stress and postharvest treatment significantly altered the antioxidant properties of wheat grain fractions. The ORAC values of Ankor bran and corresponding 40-mesh bran samples kept at 100 degrees C for 9 days reduced to 61 and 40% of that at day 0 on a per dry weight basis, respectively, while the ORAC values of the grain samples showed no significant change. The overall loss of DPPH. scavenging capacity was 38 and 100% for the bran and 40-mesh Ankor bran samples, respectively, and was 47 and 60% in the bran and 40-mesh Trego bran samples, respectively, whereas no reduction was detected in the grain samples under the same heat stress. Heat stress and postharvest treatment had similar effects on ABTS.+ scavenging capacities and TPC values of grain and fractions of both varieties. These data suggest that whole grain as opposed to its fractions is a preferred form of long-term storage for better preserving natural antioxidants and that the reduction of the particle size may accelerate the loss of natural antioxidants in wheat bran during storage and thermal processing but may enhance the releasable amount of wheat antioxidants from bran. more...
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- 2006
159. Role of Zn2+ in epigallocatechin gallate affecting the growth of PC-3 cells
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Shengrong Shen, Xun Chen, Jun-Jie Yin, and Haining Yu
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Male ,medicine.medical_specialty ,Cell Survival ,Prostate cancer cell ,Epigallocatechin gallate ,Inhibitory postsynaptic potential ,complex mixtures ,Biochemistry ,Catechin ,Inorganic Chemistry ,chemistry.chemical_compound ,Prostate cancer ,Internal medicine ,Cell Line, Tumor ,medicine ,Carcinoma ,Anticarcinogenic Agents ,Humans ,heterocyclic compounds ,Tea ,Cell growth ,Chemistry ,food and beverages ,Prostatic Neoplasms ,Green tea ,medicine.disease ,Zinc ,Endocrinology ,Cancer research ,Molecular Medicine ,sense organs ,Prostate gland - Abstract
Green tea has chemo-preventive effects to human carcinoma including prostate cancer. Epigallocatechin gallate (EGCG) is the major active component in green tea. Zn 2+ is indispensable to our health, and plays an important role in the normal function and pathology of the prostate gland, and might be a good marker for diagnosing prostate cancer. Effects of Zn 2+ , EGCG and their interactions on the growth of androgen-insensitive prostate cancer cell (PC-3) were investigated in the present paper. The results show that Zn 2+ and EGCG inhibited the growth of PC-3 cells in a time- and dose-dependent manner, but effects of interactions of EGCG with Zn 2+ were extremely dependent on their concentrations and added orders. Inhibitory effects of Zn 2+ were significantly decreased in the presence of EGCG on PC-3 cell growth. Therefore, we hypothesize that complexation of EGCG with Zn 2+ might be responsible for the observed decrease of the bioactivities of Zn 2+ against PC-3 cells. more...
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- 2006
160. Different roles for K+ channels in cisplatin-resistant cell lines argue against a critical role for these channels in cisplatin resistance
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Xing-Jie, Liang, Barbara, Taylor, Carol, Cardarelli, Jun-Jie, Yin, Jean-Philippe, Annereau, Susan, Garfield, Stephen, Wincovitch, Gergely, Szakács, Michael M, Gottesman, and Adorjan, Aszalos
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Cell Membrane ,Liver Neoplasms ,Gene Expression ,Antineoplastic Agents ,Cell Growth Processes ,Intracellular Membranes ,Ether-A-Go-Go Potassium Channels ,KB Cells ,Membrane Potentials ,Mitochondria ,Oxygen Consumption ,Drug Resistance, Neoplasm ,Cell Line, Tumor ,Potassium ,Potassium Channel Blockers ,Humans ,Cisplatin ,Omeprazole ,Oligonucleotide Array Sequence Analysis - Abstract
Cisplatin resistance has been associated with altered K+ fluxes. Here, we focused our investigations on the detection of K+ channels in a series of cisplatin-resistant (CP-r) cells with increasing resistance and on the functional relationship of these K+ channels to resistance. Microarray analysis and confocal microscopy indicated that there was overexpression of the ether-a-gogo gene (HERG) and the inwardly rectifying potassium channel gene (TWIK) in a human epidermal KB and human liver BEL-7404 carcinoma cell line series selected for cisplatin resistance. With increased resistance, the plasma membrane potential, but not the mitochondrial membrane potential, also increases in these two series. For these reasons, we conducted cell proliferation studies in the presence of either antibodies directed against the detected K+ channels, omeprazole (a H+ pump inhibitor) or a specific inhibitor of the HERG channel (WAY-123398-A-5). The antibodies and omeprazole influenced cell growth only very slightly. The specific K+ channel blocker did not alter cisplatin resistance. We also observed that manipulation of K+ fluxes with antibodies and the H+ pump with omeprazole resulted in opposite effects on cisplatin resistance in these two cell lines. We conclude that K+ and H+ homeostasis are not critical factors in cisplatin resistance since they affect cisplatin resistance differently in KB and BEL-7404 cells. more...
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- 2005
161. Spectroelectrochemical Reverse Engineering Demonstrates That Melanin's Redox and Radical Scavenging Activities Are Linked.
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Eunkyoung Kim, Mijeong Kang, Tschirhart, Tanya, Malo, Mackenzie, Dadachova, Ekaterina, Gaojuan Cao, Jun-Jie Yin, Bentley, William E., Zheng Wang, and Payne, Gregory F.
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- 2017
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162. Effects of P25 TiO2 Nanoparticles on the Free Radical-Scavenging Ability of Antioxidants upon Their Exposure to Simulated Sunlight.
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Meng Li, Yu Chong, Fu, Peter P., Qingsu Xia, Croley, Timothy R., Lo, Y. Martin, and Jun-Jie Yin
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- 2017
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163. UVA photoirradiation of retinyl palmitate--formation of singlet oxygen and superoxide, and their role in induction of lipid peroxidation
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Wayne G. Wamer, Qingsu Xia, Jun-Jie Yin, Paul C. Howard, Shu-Hui Cherng, Peter P. Fu, and Mary D. Boudreau
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Retinyl Esters ,Ultraviolet Rays ,chemistry.chemical_element ,Pyrroline ,Toxicology ,medicine.disease_cause ,Photochemistry ,Oxygen ,Antioxidants ,Lipid peroxidation ,chemistry.chemical_compound ,Superoxides ,Retinyl palmitate ,medicine ,Vitamin A ,chemistry.chemical_classification ,Reactive oxygen species ,Singlet Oxygen ,Singlet oxygen ,Superoxide ,Electron Spin Resonance Spectroscopy ,General Medicine ,chemistry ,Linoleic Acids ,Lipid Peroxidation ,Diterpenes ,Oxidative stress - Abstract
We have previously reported that photoirradiation of retinyl palmitate (RP) in ethanol with UVA light results in the formation of photodecomposition products, including 5,6-epoxy-RP and anhydroretinol (AR). Photoirradiation in the presence of a lipid, methyl linoleate, induced lipid peroxidation, suggesting that reactive oxygen species (ROS) are formed. In the present study, we employ an electron spin resonance (ESR) spin trap technique to provide direct evidence as to whether or not photoirradiation of RP by UVA light produces ROS. Photoirradiation of RP by UVA in the presence of 2,2,6,6-tetramethylpiperidine (TEMP), a specific probe for singlet oxygen, resulted in the formation of TEMPO, indicating that singlet oxygen was generated. Both 5,5-dimethyl N-oxide pyrroline (DMPO) and 5-tert-butoxycarbonyl 5-methyl-1-pyrroline N-oxide (BMPO) are specific probes for superoxide. When photoirradiation of RP was conducted in the presence of the DMPO or BMPO, ESR signals for DMPO- OOH or BMPO- OOH were obtained. These results unambiguously confirmed the formation of superoxide radical anion. Consistent with a free radical mechanism, there was a near complete and time-dependent photodecomposition of RP and its photodecomposition products. ESR studies on the photoirradiation of 5,6-epoxy-RP and AR indicate that these compounds exhibit similar photosensitizing activities as RP under UVA light. more...
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- 2005
164. Photodecomposition and Phototoxicity of Natural Retinoids
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Mary D. Boudreau, Shui-Hui Cherng, Paul C. Howard, Qingsu Xia, Wayne G. Wamer, Peter P. Fu, Hongtao Yu, Jun-Jie Yin, and William H. Tolleson
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medicine.drug_class ,Photochemistry ,Ultraviolet Rays ,Health, Toxicology and Mutagenesis ,Retinoic acid ,lcsh:Medicine ,Cosmetics ,Retinyl acetate ,Article ,vitamin A ,chemistry.chemical_compound ,Retinoids ,phototoxicity ,Retinyl palmitate ,medicine ,retinoic acid ,Animals ,Humans ,Retinoid ,Carcinogen ,integumentary system ,Retinol ,lcsh:R ,Public Health, Environmental and Occupational Health ,chemistry ,Biochemistry ,Toxicity ,retinyl palmitate ,photocarcinogenicity ,Lipid Peroxidation ,Phototoxicity ,Reactive Oxygen Species ,DNA Damage - Abstract
Sunlight is a known human carcinogen. Many cosmetics contain retinoid-based compounds, such as retinyl palmitate (RP), either to protect the skin or to stimulate skin responses that will correct skin damaged by sunlight. However, little is known about the photodecomposition of some retinoids and the toxicity of these retinoids and their sunlight-induced photodecomposition products on skin. Thus, studies are required to test whether topical application of retinoids enhances the phototoxicity and photocarcinogenicity of sunlight and UV light. Mechanistic studies are needed to provide insight into the disposition of retinoids in vitro and on the skin, and to test thoroughly whether genotoxic damage by UV-induced radicals may participate in any toxicity of topically applied retinoids in the presence of UV light. This paper reports the update information and our experimental results on photostability, photoreactions, and phototoxicity of the natural retinoids including retinol (ROH), retinal, retinoid acid (RA), retinyl acetate, and RP (Figure 1). more...
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- 2005
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165. Oral administration of Crataegus flavonoids protects against ischemia/reperfusion brain damage in gerbils
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De-Liang, Zhang, Yue-Ting, Zhang, Jun-Jie, Yin, and Bao-Lu, Zhao
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Male ,Free Radicals ,Administration, Oral ,Nitric Oxide Synthase Type II ,Hippocampus ,Thiobarbituric Acid Reactive Substances ,Antioxidants ,Animals ,RNA, Messenger ,Nitrites ,Brain Chemistry ,Cell Nucleus ,Flavonoids ,Crataegus ,Nitrates ,Dose-Response Relationship, Drug ,Plant Extracts ,Tumor Necrosis Factor-alpha ,Pyramidal Cells ,NF-kappa B ,Transcription Factor RelA ,Disease Models, Animal ,Neuroprotective Agents ,Ischemic Attack, Transient ,Reperfusion Injury ,Nitric Oxide Synthase ,Gerbillinae ,DNA Damage - Abstract
Stroke is the third leading cause of death as dementia is a main symptom of Alzheimer's disease. One of the important mechanisms in the pathogeny of stroke is free radical production during the reperfusion period, therefore the effects of a type of natural antioxidant, i.e. Crataegus flavonoids (CF), on brain ischemic insults were investigated in Mongolian gerbil stroke model. Results showed that pretreatment of the animals with CF decreased reactive oxygen species (ROS) production, thiobarbituric acid reactive substances content, and nitrite/nitrate concentration in brain homogenate, increased the brain homogenate-associated antioxidant level in a dose-dependent manner. CF pretreatment increased the amount of biologically available NO by scavenging of superoxide anion produced during reperfusion. At same time, in the process of ischemia/reperfusion brain damage, the content of nitrite/nitrate (the end product of NO) increased, and of NO detected by ESR decreased. Oral pretreatment with CF decreased the nitrite/nitrate content in the brain homogenate and increased the biologically available NO concentration in a dose-dependent manner. The increasing effect of antioxidant on NO might be due to its scavenging effect on superoxide anion, which could react with NO into peroxynitrite. iNOS was implied in delayed neuron death after brain ischemic damage and it was found that pretreatment with CF could decrease the protein level of tumor necrosis factor (TNF)-alpha and nuclear factor-kappa B (NF-kappaB), and increase the mRNA level of NOS estimated by western blotting and RT-PCR. More neurons survived and fewer cells suffered apoptosis in the hippocampal CA1 region of CF treated animal brain. These results suggest that oral administration of this antioxidant increases the antioxidant level in the brain and protects the brain against delayed cell death caused by ischemia/reperfusion injury. more...
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- 2004
166. Synergistic effect of Scutellaria baicalensis and grape seed proanthocyanidins on scavenging reactive oxygen species in vitro
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Kim Chan Chan, Paul T. Schumacker, Lance B. Becker, Yimin Qin, Jun-Jie Yin, Chang Qing Li, Zuo-Hui Shao, Chun-Su Yuan, and Terry L. Vanden Hoek
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food.ingredient ,Antioxidant ,Radical ,medicine.medical_treatment ,Iron ,complex mixtures ,Plant Roots ,law.invention ,chemistry.chemical_compound ,food ,law ,medicine ,Humans ,Proanthocyanidins ,Vitis ,Xanthine oxidase ,chemistry.chemical_classification ,Reactive oxygen species ,biology ,Traditional medicine ,Plant Extracts ,food and beverages ,Drug Synergism ,General Medicine ,Free Radical Scavengers ,Hydrogen Peroxide ,biology.organism_classification ,Xanthine ,Complementary and alternative medicine ,chemistry ,Herb ,Seeds ,Scutellaria baicalensis ,Phytotherapy ,Reactive Oxygen Species - Abstract
Scutellaria baicalensis (SbE) is a commonly used Chinese herb medicine and grape seed proanthocyanidins is a popular herbal supplement in the United States. Both herbs have been shown to possess potent antioxidant effects. Using an in vitro model to produce the reactive oxygen species (ROS) generation ( H 2 O 2/ FeSO 4 for hydroxyl radicals, xanthine/xanthine oxidase for suproxide), we observed that Scutellaria baicalensis and grape seed proanthocyanidins acted synergistically to scavenge ROS. Our data suggest that a combination of these two herbs can potentially enhance their antioxidant efficacy, allowing lower dosages of each drug to be used. This has the advantage of avoiding possible side effects that may arise when higher doses of a single herb are used in an attempt to achieve a maximum degree of antioxidant activity. more...
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- 2004
167. Growth inhibition of prostate cancer cells by epigallocatechin gallate in the presence of Cu2+
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Jun-Jie Yin, Hai-Ning Yu, and Sheng-Rong Shen
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Adenoma ,Male ,medicine.medical_specialty ,Free Radicals ,Cell Survival ,Epigallocatechin gallate ,urologic and male genital diseases ,complex mixtures ,Catechin ,Prostate cancer ,chemistry.chemical_compound ,Internal medicine ,medicine ,Tumor Cells, Cultured ,Humans ,heterocyclic compounds ,Chemistry ,food and beverages ,Cancer ,Prostatic Neoplasms ,Biological activity ,General Chemistry ,medicine.disease ,Endocrinology ,Apoptosis ,Luminescent Measurements ,Cancer research ,sense organs ,Growth inhibition ,General Agricultural and Biological Sciences ,Cell Division ,Copper - Abstract
Green tea is an effective chemopreventive agent to human prostate cancer adenoma (PCA). Epigallocatechin gallate (EGCG) inhibited the growth of PCA cells and induced apoptosis. Cu(2+) is a trace element necessary to our health. Many studies proved that bioactivity of EGCG is altered in the presence of Cu(2+). We investigated the effects of EGCG on PCA cells in the presence of Cu(2+). Also, we explored potential mechanisms via measurement of the relative chemiluminescence of growth medium for PCA cells. Chemiluminscence can be an indication of free radicals. Our test results showed that the addition of EGCG and Cu(2+) to the growth medium decreased the relative viability of androgen-sensitive and androgen-insensitive human prostate cancer cells. However, the effects of EGCG on PCA cells depended on (1) the relative concentrations of added EGCG and Cu(2+) and (2) their order of addition. Our results indicated that few free radicals may be generated in vitro. If so, free radicals generated intracellularly may be a major factor behind apoptosis and growth inhibition observed in the PCA cells. Thus, EGCG might exert its effects intracellularly. more...
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- 2004
168. Spin-label EPR $T_{1}$ values using saturation recovery from 2 to 35 GHz
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Theodore G. Camenisch, Wojciech Froncisz, Witold K. Subczynski, James S. Hyde, Joseph J. Ratke, and Jun-Jie Yin
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Spectrometer ,Chemistry ,Relaxation (NMR) ,Analytical chemistry ,Electron ,Surfaces, Coatings and Films ,law.invention ,Free induction decay ,Resonator ,law ,Materials Chemistry ,Physical and Theoretical Chemistry ,Atomic physics ,Electron paramagnetic resonance ,Spin (physics) ,Spin label - Abstract
EPR saturation-recovery (SR) measurements of the electron spin-lattice relaxation time, T 1, of nitroxideradical spin probes have been made from 2 to 35 GHz. T1 values of small water-soluble spin probes increase linearly with microwave frequency throughout the full range of available frequencies. T1 values of four commonly used hydrophobic probes in lipid bilayers also increase with frequency, but the dependence is weaker and complex. Contributions of dissolved molecular oxygen to relaxation rates were independent of microwave frequency. T1 values of 15 N-containing labels are always somewhat longer than for 14 N labels. Details of the Q-band SR spectrometer, which is based on frequency translation technology, are provided. A new way to suppress free induction decay signals in SR experiments has been found: pump and observing frequencies time-locked and separated by about 1 kHz in frequency. A novel three-loop-two-gap resonator with a sample volume of 30 nl was used for the Q-band measurements. It is concluded that Q-band is a favorable frequency for SR spin-label oximetry studies. more...
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- 2004
169. P-glycoprotein, expressed in multidrug resistant cells, is not responsible for alterations in membrane fluidity or membrane potential
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Claudina, Alemán, Jean-Philippe, Annereau, Xing-Jie, Liang, Carol O, Cardarelli, Barbara, Taylor, Jun Jie, Yin, Adorjan, Aszalos, and Michael M, Gottesman
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Membrane Fluidity ,Recombinant Fusion Proteins ,Electron Spin Resonance Spectroscopy ,Proton Pumps ,Tetracycline ,Transfection ,Drug Resistance, Multiple ,Membrane Potentials ,Neoplasm Proteins ,Gene Expression Regulation, Neoplastic ,Drug Resistance, Neoplasm ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,RNA, Messenger ,RNA, Neoplasm ,Half-Life ,HeLa Cells - Abstract
Expression of P-glycoprotein (P-gp), the multidrug resistance (MDR) 1 gene product, can lead to MDR in tumors. However, the physiological role of P-gp in normal tissues is not well understood. Previous studies on multidrug-resistant cells have suggested changes in membrane fluidity and membrane potential associated with P-gp expression, but interpretation of these studies is difficult, because most experimental cells have been selected for long periods in the presence of cytotoxic drugs and may have other host alterations. Therefore, we created two cell lines in which a transfected human MDR1 cDNA is repressed by tetracycline and induced in the absence of tetracycline. One cell line was derived from a mouse embryonic fibroblast cultured from a double (mdr1a/1b) knockout mouse, and the other was from a human HeLa cell line. Analysis of the kinetics of expression of P-gp showed that the mRNA had a half-life of approximately 4 h, and the protein had a half-life of approximately 16 h. P-gp cell surface expression (measured with monoclonal antibody MRK-16) and P-gp function (measured with a fluorescent substrate, rhodamine 123) was characterized by using fluorescence-activated cell sorting. No differences in membrane potential using the fluorescent probe oxonol or in membrane "fluidity" using fluorescent anisotropy probe or electron spin resonance probe were observed in the tet-repressible P-gp-expressing cells. In contrast, several drug-selected cells that express P-gp showed an increase in membrane fluidity and membrane potential. These results suggest that expression of P-gp per se has little effect on membrane fluidity or membrane potential, and it does not have H(+) pump activity. The changes in these parameters observed in drug-selected cells must reflect other host adaptations to drug selection. more...
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- 2003
170. Sodium tanshinone IIA sulfonate mediates electron transfer reaction in rat heart mitochondria
- Author
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Guangyin Zhou, Jun-Jie Yin, Baolu Zhao, Wenjuan Xin, Guang-En Ma, Yan Zhao, and Wen Jiang
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Male ,Antioxidant ,Semiquinone ,Stereochemistry ,medicine.medical_treatment ,Radical ,Respiratory chain ,Antimycin A ,Biochemistry ,Mitochondria, Heart ,Electron Transport ,Electron transfer ,chemistry.chemical_compound ,medicine ,Animals ,Rats, Wistar ,Pharmacology ,biology ,Hydroxyl Radical ,Cytochrome c ,Phenanthrenes ,NAD ,Rats ,chemistry ,Luminescent Measurements ,Biophysics ,biology.protein ,Ferricyanide ,Oxidation-Reduction ,Drugs, Chinese Herbal - Abstract
In this paper, an electron transfer reaction mediated by sodium tanshinone IIA sulfonate (STS) was studied in rat heart mitochondria. It was found that STS could stimulate mitochondrial NADH oxidation dose-dependently and partly restore NADH oxidation in the presence of respiratory inhibitor (rotenone or antimycin A or KCN). It was likely that STS could accept electrons from complex I similar to ferricyanide and could be converted to its semiquinone form that could then reduce oxygen molecule. The data also showed that cytochrome c (Cyt c) could be reduced by STS in the presence of KCN, or STS could transfer the electron to oxygen directly. Free radicals were involved in the process. The results suggest that STS may protect ischemia-reperfusion injury through an electron transfer reaction in mitochondria against forming reactive oxygen radicals. more...
- Published
- 2002
171. Pulse EPR detection of lipid exchange between protein-rich raft and bulk domains in the membrane : methodology development and its application to studies of influenza viral membrane
- Author
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Jun-Jie Yin, James S. Hyde, Akihiro Kusumi, Kazunori Kawasaki, and Witold K. Subczynski
- Subjects
Membrane lipids ,Biophysics ,Hemagglutinins, Viral ,Neuraminidase ,Models, Biological ,Biophysical Phenomena ,Membrane Lipids ,Viral Envelope Proteins ,Spin label ,biology ,Chemistry ,Pulsed EPR ,urogenital system ,Electron Spin Resonance Spectroscopy ,Oxygen transport ,Membrane Proteins ,Bacteriorhodopsin ,Raft ,Viral membrane ,Orthomyxoviridae ,Protein Structure, Tertiary ,Oxygen ,Crystallography ,Cholesterol ,Membrane ,biology.protein ,Research Article - Abstract
A pulse saturation-recovery electron paramagnetic resonance (EPR) method has been developed that allows estimation of the exchange rates of a spin-labeled lipid between the bulk domain and the protein-rich membrane domain, in which the rate of collision between the spin label and molecular oxygen is reduced (slow-oxygen transport domain, or SLOT domain). It is based on the measurements of saturation-recovery signals of a lipid spin label as a function of concentrations of both molecular oxygen and the spin label. Influenza viral membrane, one of the simplest paradigms for the study of biomembranes, showed the presence of two membrane domains with slow and fast collision rates with oxygen (a 16-fold difference) at 30 degrees C. The outbound rate from and the inbound rate into the SLOT domain (or possibly the rate of the domain disintegration and formation) were estimated to be 7.7 x 10(4) and 4.6 x 10(4) s(-1), (15 micros residency time), respectively, indicating that the SLOT domain is highly dynamic and that the entire SLOT domain represents about one-third of the membrane area. Because the oxygen transport rate in the SLOT domain is a factor of two smaller than that in purple membrane, where bacteriorhodopsin is aggregated, we propose that the SLOT domain in the viral membrane is the cholesterol-rich raft domain stabilized by the trimers of hemagglutinin and/or the tetramers of neuraminidase. more...
- Published
- 2001
172. Prussian Blue Nanoparticles as Multienzyme Mimetics and Reactive Oxygen Species Scavengers.
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Wei Zhang, Sunling Hu, Jun-Jie Yin, Weiwei He, Wei Lu, Ming Ma, Ning Gu, and Yu Zhang
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- 2016
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173. Intravenous administration of silver nanoparticles causes organ toxicity through intracellular ROS-related loss of interendothelial junction.
- Author
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Hua Guo, Jing Zhang, Mary Boudreau, Jie Meng, Jun-jie Yin, Jian Liu, and Haiyan Xu
- Subjects
SILVER nanoparticles ,ORGANS (Anatomy) ,INTRAVENOUS injections ,ENDOTHELIAL cells ,TOXICITY testing ,SILVER ions - Abstract
Background: Administration of silver nanoparticles (AgNPs) to mice could result in their distribution and accumulation in multiple organs, with notable prominence in liver, lungs, and kidneys. However, how AgNPs transport through blood vesicular system to reach the target organs is unclear, and the precise differences in the mechanisms of toxicity between AgNPs and silver ions still remain elusive. In the present research, the pathological changes on these target organs with a focus on inter-endothelial junction was investigated to gain a new insight of AgNPs toxicity by comparing the mechanisms of action of AgNPs and AgNO
3 . Methods: We investigated the in vitro cytotoxicity of either citrated-coated AgNPs (10, 75, and 110 nm) or silver nitrate (AgNO3) following 24 h incubations (1-40 µg/mL) in the presence of primary human umbilical vein endothelial cells (HUVEC). Meanwhile, we detected the effects of AgNPs on intercellular conjunction and intracellular ROS by VE-cadherin staining and 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay, respectively. To assess in vivo toxicity, we administered single or multiple intravenous injections (25 µg Ag for AgNPs and 2.5 µg Ag for AgNO3 per dose) to mice. Results: In the in vitro study, the TEM observation showed that AgNPs were taken up by endothelial cells while AgNO3 was taken up little. Meanwhile AgNPs incubation induced the elevation of intracellular ROS and down-regulation of VEcadherin between the endothelial cells and affected the cytoskeleton actin reorganization, which could be rescued by antioxidant N-acetylcysteine. In contrast, AgNO3 caused direct cell death when the concentration was higher than 20 µg/mL and without ROS induction at lower concentration. The release of AgNPs from leaking vessels induced peripheral inflammation in the liver, lungs, and kidneys, and the severity increased in proportion to the diameter of the AgNPs used. Conclusion: It is AgNPs but not AgNO3 that were taken up by vascular endothelial cells and induced intracellular ROS elevated, which was closely related to disruption of the integrity of endothelial layer. The AgNPs-induced leakiness of endothelial cells could mediate the common peripheral inflammation in liver, kidney and lung through intravenous exposure. [ABSTRACT FROM AUTHOR] more...- Published
- 2016
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174. Au@PtAg core/shell nanorods: tailoring enzyme-like activities via alloying
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Shuai Hou, Tao Wen, Xiaochun Wu, Jun-Jie Yin, Aditya Saran, Yinglu Ji, Xiaona Hu, Hui Zhang, Wenqi Liu, and Weiwei He
- Subjects
chemistry.chemical_classification ,Reactive oxygen species ,Antioxidant ,biology ,General Chemical Engineering ,medicine.medical_treatment ,Radical ,Substrate (chemistry) ,Nanotechnology ,General Chemistry ,Combinatorial chemistry ,Superoxide dismutase ,chemistry ,Catalase ,medicine ,biology.protein ,Enzyme kinetics ,Peroxidase - Abstract
Pt nanoparticles (NPs) have been reported to demonstrate four kinds of enzyme-like activity including superoxide dismutase (SOD), catalase, oxidase and peroxidase. Some of these activities interfere with each other. For instance, as antioxidant enzyme mimics, their SOD and catalase activities are very helpful in scavenging related reactive oxygen species (ROSs). However, their oxidase-like and/or peroxidase-like activities may simultaneously oxidize some natural antioxidants, thus compromising the final anti-oxidation efficacy. Fine tuning different enzyme-like activities is therefore very important to realize the optimization of their functions. In this paper, our effort is focused in this direction by tailoring the electronic structure of Pt NPs via alloying with Ag. All four enzyme-like activities are found to be weakened by an increased Ag percentage in the alloy, as witnessed by decreased values of Kcat. The variation in the electronic structure also changes the substrate affinity. Introducing silver into Pt weakens the affinity for H2O2, which affects the limit of detection (LOD) for H2O2 and products with H2O2 involved. In contrast to Fe3O4 MNPs, for peroxidase-like activity, hydroxyl radicals are not involved in the oxidation of chromogenic substrates for the alloy nanostructures. more...
- Published
- 2013
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175. Self-doping and surface plasmon modification induced visible light photocatalysis of BiOCl
- Author
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Jing Jiang, Hao Li, Lizhi Zhang, Weiwei He, and Jun-Jie Yin
- Subjects
Photocurrent ,Materials science ,business.industry ,Surface photovoltage ,Surface plasmon ,Physics::Optics ,Photochemistry ,X-ray photoelectron spectroscopy ,Photocatalysis ,Optoelectronics ,General Materials Science ,Surface plasmon resonance ,business ,Spectroscopy ,Plasmon - Abstract
In this study we demonstrate that self-doping and surface plasmon resonance could endow a wide-band-gap ternary semiconductor BiOCl with remarkable visible light driven photocatalytic activity on the degradation of organic pollutants and photocurrent generation properties. The self-doped BiOCl with plasmonic silver modification was synthesized by a facile one-pot nonaqueous approach and systematically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-visible diffuse reflectance spectra, electron spin resonance, and X-ray photoelectron spectroscopy. The photocurrent enhancement was found to be intimately dependent on the irradiation wavelength and matched well with the intensity of the absorption of the Ag nanoparticles. Reactive species trapping experiments and electron spin resonance spectroscopy with 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping adducts confirmed that more oxidative species could be generated from the photogenerated electrons due to the plasmon-excitation of the metallic Ag in the self-doped BiOCl with plasmonic silver modification, which is responsible for the great enhancement of photocatalytic activity and photocurrent. Surface photovoltage spectroscopy and time-resolved photoluminescence spectroscopy results revealed the transfer of plasmon-band-induced electrons from Ag nanoparticles into BiOCl and the acceleration effect of surface plasmon resonance-induced intense oscillating electric fields on this electron transfer. This study would not only provide direct evidence of plasmonic photocatalysis, but also shed light on the design of highly efficient metal-semiconductor composite photocatalysts. more...
- Published
- 2013
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176. Enzyme-mimetic effects of gold@platinum nanorods on the antioxidant activity of ascorbic acid
- Author
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Weiwei He, Jun-Jie Yin, Y. Martin Lo, Xiaochun Wu, Wayne G. Wamer, Xiaona Hu, and Yu-Ting Zhou
- Subjects
Antioxidant ,Macromolecular Substances ,Surface Properties ,Reducing agent ,DPPH ,medicine.medical_treatment ,Radical ,Molecular Conformation ,Metal Nanoparticles ,chemistry.chemical_element ,Ascorbic Acid ,Photochemistry ,Antioxidants ,chemistry.chemical_compound ,Materials Testing ,medicine ,General Materials Science ,Particle Size ,Platinum ,Chemistry ,Ascorbic acid ,Enzyme Activation ,Titanium dioxide ,Nanorod ,Gold ,Oxidoreductases - Abstract
Au@Pt nanorods were prepared by growing platinum nanodots on gold nanorods. Using electron spin resonance (ESR), we determined that the mechanisms for oxidation of ascorbic acid (AA) by Au@Pt nanorods and ascorbic acid oxidase (AAO) were kinetically similar and yielded similar products. In addition we observed that Au@Pt nanorods were stable with respect to temperature and pH. Using UV-VIS spectroscopy, the apparent kinetics of enzyme-mimetic activity of Au@Pt nanorods were studied and compared with the activity of AAO. With the help of ESR, we found that Au@Pt nanorods did not scavenge hydroxyl radicals but inhibited the antioxidant ability of AA for scavenging hydroxyl radicals produced by photoirradiating solutions containing titanium dioxide and zinc oxide. Moreover, the Au@Pt nanorods reduced the ability of AA to scavenge DPPH radicals and superoxide radicals. These results demonstrate that Au@Pt nanorods can reduce the antioxidant activity of AA. Therefore, it is necessary to consider the effects of using Pt nanoparticles together with other reducing agents or antioxidants such as AA due to the oxidase-like property of Au@Pt nanorods. more...
- Published
- 2013
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- View/download PDF
177. Effects of fumonisin B1 on oxygen transport in membranes
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Mitchell J. Smith, James A. Sphon, Robert M. Eppley, Samuel W. Page, and Jun-Jie Yin
- Subjects
Inorganic chemistry ,Lipid Bilayers ,Biophysics ,chemistry.chemical_element ,Biochemistry ,Oxygen ,Fumonisins ,law.invention ,Diffusion ,chemistry.chemical_compound ,law ,Phosphatidylcholine ,Mole ,Organic chemistry ,Electron paramagnetic resonance ,Molecular Biology ,chemistry.chemical_classification ,Fumonisin B1 ,Oxygen transport ,Electron Spin Resonance Spectroscopy ,Cell Biology ,Mycotoxins ,Carcinogens, Environmental ,Membrane ,Hydrocarbon ,chemistry ,Phosphatidylcholines ,Spin Labels ,Dimyristoylphosphatidylcholine - Abstract
Electron spin resonance (ESR) spin-label oximetry has been used to study the effects of fumonisin B1 (FB1), a sphingoid-like mycotoxin, on oxygen transport in phosphatidylcholine (PC) bilayers. Moreover, the use of spin labels attached to different carbons of fatty acids makes it possible to do structural and oximetric determinations with the same test sample. Specifically, the incorporation of 10 mol% FB1 increased the oxygen transport properties of both saturated and unsaturated membranes at 37 degrees C by ca. 30% and decreased the ordering of the hydrocarbon chains near the surface of the membranes; concomitantly, oxygen transport near the center of bilayers was diminished slightly, and the relative oxygen diffusion-concentration product profile curves were markedly flattened. more...
- Published
- 1996
178. Effects of lutein and cholesterol on alkyl chain bending in lipid bilayers: a pulse electron spin resonance spin labeling study
- Author
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Jun-Jie Yin and Witold K. Subczynski
- Subjects
Lutein ,Time Factors ,Lipid Bilayers ,Biophysics ,Analytical chemistry ,Molecular Conformation ,law.invention ,chemistry.chemical_compound ,law ,Phosphatidylcholine ,Electron paramagnetic resonance ,Lipid bilayer ,Alkyl ,chemistry.chemical_classification ,Electron Spin Resonance Spectroscopy ,food and beverages ,Site-directed spin labeling ,Egg Yolk ,Models, Structural ,Crystallography ,Kinetics ,Membrane ,Cholesterol ,chemistry ,Phosphatidylcholines ,lipids (amino acids, peptides, and proteins) ,Spin Labels ,Stearic acid ,Dimyristoylphosphatidylcholine ,Research Article - Abstract
A short pulse saturation recovery electron spin resonance technique has been used to study the effects of polar carotenoid-lutein and cholesterol on interactions of 14N:15N stearic acid spin-label pairs in fluid-phase phosphatidylcholine (PC) membranes. Bimolecular collisions for pairs consisting of various combinations of [14N]-16-, [14N]-10-, [14N]-7-, or [14N]-5-doxylstearate and [15N]-16-doxylstearate in dimyristoyl-PC (DMPC) or egg yolk PC (EYPC) membranes were measured at 27 degrees C. In the absence and presence of lutein or cholesterol for both lipid systems, the collision rates were ordered as 16:5 < 16:7 < 16:10 < 16:16. For all spin-label pairs studied, interaction frequencies were greater in DMPC than in EYPC. Polar carotenoid-lutein reduces the collision frequency for all spin-label pairs, whereas cholesterol reduces the collision frequency for 16:5 and 16:7 pairs and increases the collision frequency in the membrane center for 16:10 and 16:16 pairs. The presence of unsaturated alkyl chains greatly reduces the effect of lutein but magnifies the effect of cholesterol in the membrane center. The observed differences in the effects of these modifiers on alkyl chain bending result from differences in the structure of cholesterol and polar carotenoid and from their different localization within the lipid bilayer membrane. These studies further confirm the occurrence of vertical fluctuations of alkyl chain ends toward the bilayer surface. more...
- Published
- 1996
179. The contributions of metal impurities and tube structure to the toxicity of carbon nanotube materials
- Author
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Jun-Jie Yin, Yang Li, Yuliang Zhao, Liming Wang, Ying Liu, Chunying Chen, and Cuicui Ge
- Subjects
Nanotube ,Chemistry ,Metal impurities ,Inorganic chemistry ,Carbon nanotube ,Condensed Matter Physics ,law.invention ,Metal ,law ,Modeling and Simulation ,visual_art ,Toxicity ,visual_art.visual_art_medium ,General Materials Science ,Ceramic ,Metallic impurities ,Biosensor - Abstract
Carbon nanotubes (CNTs) are a class of materials that have stimulated a great deal of interest among researchers due to their unique chemical and electronic properties. However, the apparent toxicity of CNTs has raised concerns about their use in research and applications. Chunying Chen and Yuliang Zhao at the Chinese Academy of Sciences in Beijing and their co-workers have re-examined the safety profile of CNTs, highlighting the role that metallic impurities left over from nanotube synthesis play in their toxicity. The researchers found that these metallic particles readily leach out of the nanotubes, including into simulated biological fluids mimicking those found in the lung, stomach and intestines. Iron particles leached into acidic fluids caused particular safety concerns—electron-spin resonance analysis showed that leached iron particles were generating cytotoxic free radical species at levels much higher than the nanotubes themselves. Cell viability studies demonstrated a clear negative correlation between the amount of metal residue in the nanotube sample and the health of the cultured cells. more...
- Published
- 2012
- Full Text
- View/download PDF
180. Graphene: Unraveling Stress-Induced Toxicity Properties of Graphene Oxide and the Underlying Mechanism (Adv. Mater. 39/2012)
- Author
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Xingfa Gao, Jun-Jie Yin, Yiye Li, Ying Fang, Chi Wang, Guangjun Nie, Zhongjun Li, Yu-Ting Zhou, Wendi Zhang, Yuliang Zhao, and Zhenzhen Lu
- Subjects
Materials science ,Graphene ,Mechanical Engineering ,Stress induced ,Oxide ,Nanotechnology ,law.invention ,chemistry.chemical_compound ,Electron transfer ,chemistry ,Mechanics of Materials ,Nanotoxicology ,law ,Toxicity ,General Materials Science ,Mechanism (sociology) - Published
- 2012
- Full Text
- View/download PDF
181. Hydrophobic barriers of lipid bilayer membranes formed by reduction of water penetration by alkyl chain unsaturation and cholesterol
- Author
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Akihiro Kusumi, Jun-Jie Yin, Witold K. Subczynski, James S. Hyde, and Anna Wisniewska
- Subjects
Cell Membrane Permeability ,Alkylation ,Chemical Phenomena ,Lipid Bilayers ,Biochemistry ,Spin probe ,Cyclic N-Oxides ,chemistry.chemical_compound ,Structure-Activity Relationship ,Phosphatidylcholine ,Freezing ,Organic chemistry ,Lipid bilayer ,Hydrophobicity scales ,Alkyl ,chemistry.chemical_classification ,Degree of unsaturation ,Chemistry ,Chemistry, Physical ,Bilayer ,Electron Spin Resonance Spectroscopy ,Water ,Crystallography ,Membrane ,Cholesterol ,Liposomes ,Phosphatidylcholines ,Solvents ,lipids (amino acids, peptides, and proteins) ,Spin Labels - Abstract
The hydrophobicity profiles across phosphatidylcholine (PC)-cholesterol bilayer membranes were estimated in both frozen liposome suspensions and fluid-phase membranes as a function of alkyl chain length, unsaturation, and cholesterol mole fraction. A series of stearic acid spin labels, with the probe attached to various positions along the alkyl chain, cholesterol-type spin labels (cholestane and androstane spin labels), and Tempo-PC were used to examine depth-dependent changes in local hydrophobicity, which is determined by the extent of water penetration into the membrane. Local hydrophobicity was monitored primarily by observing the z component of the hyperfine interaction tensor (Az) of the nitroxide spin probe in a frozen suspension of the membrane at -150 degrees C and was further confirmed in the fluid phase by observing the rate of collision of Fe(CN)6(3-) with the spin probe in the membrane using saturation recovery ESR. Saturated-PC membranes show low hydrophobicity (high polarity) across the membrane, comparable to 2-propanol and 1-octanol, even at the membrane center where hydrophobicity is highest. Longer alkyl chains only make the central hydrophobic regions wider without increasing the level of hydrophobicity. Introduction of a double bond at C9-C10 decreases the level of water penetration at all locations in the membrane, and this effect is considerably greater than the cis configuration than with the trans configuration. Incorporation of cholesterol (30 mol %) dramatically changes the profiles; it decreases hydrophobicity (increases water penetration) from the polar headgroup region to a depth of approximately C7 and C9 for saturated- and unsaturated-PC membranes, respectively, which is about where the bulky rigid steroid ring structure of cholesterol reaches in the membrane. Membrane hydrophobicity sharply increases at these positions from the level of methanol to the level of pure hexane, and hydrophobicity is constant in the inner region of the membrane. Thus, formation of effective hydrophobic barriers to permeation of small polar molecules requires alkyl chain unsaturation and/or cholesterol. The thickness of this rectangular hydrophobic barrier is less than 50% of the thickness of the hydrocarbon regions. Results obtained in dioleoyl-PC-cholesterol membranes in the fluid phase are similar to those obtained in frozen membranes. These results correlate well with permeability data for water and amino acids in the literature. more...
- Published
- 1994
182. Using Hollow Carbon Nanospheres as a Light-Induced Free Radical Generator To Overcome Chemotherapy Resistance.
- Author
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Liming Wang, Qiang Sun, Xin Wang, Tao Wen, Jun-Jie Yin, Pengyang Wang, Ru Bai, Xiang-Qian Zhang, Lu-Hua Zhang, An-Hui Lu, and Chunying Chen
- Published
- 2015
- Full Text
- View/download PDF
183. ChemInform Abstract: Advances in Spin Label Oximetry
- Author
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Jun-Jie Yin, Jimmy B. Feix, W. L. Hubbell, and James S. Hyde
- Subjects
chemistry ,Oxygen transport ,chemistry.chemical_element ,Continuous wave ,General Medicine ,Electron ,Atomic physics ,Saturation (chemistry) ,Spin label ,Oxygen ,Resonance (particle physics) ,Spin-½ - Abstract
Spin label oximetry is defined as the use of nitroxide radical spin labels to monitor oxygen transport. Bimolecular collisions of oxygen with spin labels alter both the longitudinal and transverse relaxation times of the spin label. Various experimental approaches can be used to observe these effects. Two of these are discussed here. (1) Saturation-recovery time-domain ESR using high observing power, rather than, as is customary, a low value, is shown to improve the sensitivity to bimolecular collisions with oxygen. First results obtained with a recently constructed S-band saturation-recovery apparatus are presented. (2) The use of electron- electron double resonance (ELDOR) as an oxygen sensitive display is considered. It is found to have substantial advantages over continuous wave (CW) saturation studies. Because it is instrumentally a simpler technique than saturation recovery, it can be useful in laboratories where acquisition of pulse equipment is unrealistic. more...
- Published
- 1990
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184. FD&C Yellow No. 5 (Tartrazine) Degradation via Reactive Oxygen Species Triggered by TiO2 and Au/Ti2 Nanoparticles Exposed to Simulated Sunlight.
- Author
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Meng Li, Weiwei He, Yi Liu, Haohao Wu, Warner, Wayne G., Martin Lo, Y., and Jun-Jie Yin
- Published
- 2014
- Full Text
- View/download PDF
185. In situ fabrication of Cu2ZnSnS4 nanoflake thin films on both rigid and flexible substrates.
- Author
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Xuezhen Zhai, Huimin Jia, Yange Zhang, Yan Lei, Jie Wei, Yuanhao Gao, Junhao Chu, Weiwei He, Jun-Jie Yin, and Zhi Zheng
- Subjects
THIN film research ,SOLAR cells ,SULFUR ,SELENIUM ,STAINLESS steel - Abstract
Cu
2 ZnSnS4 (CZTS) thin film, a highly promising and low-cost absorber layer material for solar cells, has been in situ fabricated on stainless steel and FTO glass substrates for the first time, using a one-step solvothermal treatment of CuZnSn-alloyed film with sulphur or selenium powder. The resulting products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis-NIR spectroscopy. Raman spectroscopy was used to characterize and confirm the formation of CZTS. The effects of temperature, reaction time, the ratio of Cu/Zn/Sn, and non-elemental reactants on the formation of CZTS nanocrystal films were assessed, and we found that the reaction temperature was a key factor in determining the properties of the final products. Pure CZTS phase forms at a temperature of 250 °C or higher. Our method produces CZTS thin films at 250 °C, the lowest reaction temperature that can be used in the process and the lowest temperature of any current fabrication system. We also found that flexible substrates promote the growth of CZTS nanocrystals. Using flexible substrates in the in situ fabrication of nanocrystalline thin films may make it possible to use CZTS for industrial applications. [ABSTRACT FROM AUTHOR] more...- Published
- 2014
- Full Text
- View/download PDF
186. Mechanistic characterization of titanium dioxide nanoparticle-induced toxicity using electron spin resonance.
- Author
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Meng Li, Jun-Jie Yin, Wayne G. Wamer, and Martin Lo, Y.
- Subjects
- *
NUCLEAR magnetic resonance spectroscopy , *REACTIVE oxygen species , *LIPID peroxidation (Biology) , *MOLECULAR structure , *NANOSTRUCTURES , *NUCLEIC acids , *SUPEROXIDE dismutase , *TITANIUM , *TOXICITY testing - Abstract
Titanium dioxide nanoparticles (TiO2 NPs) are one of the most widely used nanomaterials that have been manufactured worldwide and applied in different commercial realms. The well-recognized ability of TiO2 to promote the formation of reactive oxygen species (ROS) has been extensively studied as one of the important mechanisms underlying TiO2 NPs toxicity. As the "gold standard" method to quantify and identify ROS, electron spin resonance (ESR) spectroscopy has been employed in many studies aimed at evaluating TiO2 NPs safety. This review aims to provide a thorough discussion of current studies using ESR as the primary method to unravel the mechanism of TiO2 NPs toxicity. ESR spin label oximetry and immune-spin trapping techniques are also briefly introduced, because the combination of spin trapping/labeling techniques offers a promising tool for studying the oxidative damage caused by TiO2 NPs. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
- Full Text
- View/download PDF
187. Photogenerated Charge Carriers and Reactive Oxygen Species in ZnO/Au Hybrid Nanostructures with Enhanced Photocatalytic and Antibacterial Activity.
- Author
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Weiwei He, Hyun-Kyung Kim, Wamer, Wayne G., Melka, David, Callahan, John H., and Jun-Jie Yin
- Published
- 2014
- Full Text
- View/download PDF
188. Surface Structure-Dependent Molecular Oxygen Activation of BiOCl Single-Crystalline Nanosheets.
- Author
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Kun Zhao, Lizhi Zhang, Jiajun Wang, Qunxiang Li, Weiwei He, and Jun Jie Yin
- Published
- 2013
- Full Text
- View/download PDF
189. Effect of Silver Nanomaterials on the Activity of Thiol-Containing Antioxidants.
- Author
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Yu-Ting Zhou, Weiwei He, Y. Martin Lo, Xiaona Hu, Xiaochun Wu, and Jun-Jie Yin
- Published
- 2013
- Full Text
- View/download PDF
190. Core–Shell Structure Dependent Reactivity of Fe@Fe2O3 Nanowires on Aerobic Degradation of 4-Chlorophenol.
- Author
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Zhihui Ai, Zhiting Gao, Lizhi Zhang, Weiwei He, and Jun Jie Yin
- Published
- 2013
- Full Text
- View/download PDF
191. UVA Photoirradiation of Nitro-Polycyclic Aromatic Hydrocarbons-Induction of Reactive Oxygen Species and Formation of Lipid Peroxides.
- Author
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Qingsu Xia, Jun-Jie Yin, Yuewei Zhao, Yuh-Sen Wu, Yu-Qui Wang, Liang Ma, Shoujun Chen, Xin Sun, Fu, Peter P., and Hongtao Yu
- Published
- 2013
- Full Text
- View/download PDF
192. Dual Role of Selected Antioxidants Found in Dietary Supplements: Crossover between Anti-and Pro-Oxidant Activities in the Presence of Copper.
- Author
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Jun-Jie Yin, Fu, Peter P., Lutterodt, Herman, Yu-Ting Zhou, Antholine, William E., and Warner, Wayne
- Published
- 2012
- Full Text
- View/download PDF
193. Formation of PdPt Alloy Nanodots on Gold Nanorods: Tuning Oxidase-like Activities via Composition.
- Author
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Ke Zhang, Xiaona Hu, Jianbo Liu, Jun-Jie Yin, Shuai Hou, Tao Wen, Weiwei He, Yinglu Ji, Yuting Guo, Qi Wang, and Xiaochun Wu
- Published
- 2011
- Full Text
- View/download PDF
194. Metallofullerene nanoparticles circumvent tumor resistance to cisplatin by reactivating endocytosis.
- Author
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Xing-Jie Liang, Huan Meng, Yingze Wang, Haiyong He, Jie Meng, Juan Lu, Wang, Paul C., Yuliang Zhao, Xueyun Gao, Baoyun Sun, Chunying Chen, Genmei Xing, Dingwu Shen, Gottesman, Michael M., Yan Wu, Jun-jie Yin, and Lee Jia more...
- Subjects
CISPLATIN ,ENDOCYTOSIS ,PHYSIOLOGICAL effects of nanoparticles ,DRUG resistance in cancer cells ,PROSTATE cancer ,NUDE mouse ,MAGNETIC resonance imaging - Abstract
Cisplatin is a chemotherapeutic drug commonly used in clinics. However, acquired resistance confines its application in chemo-therapeutics. To overcome the acquired resistance to cisplatin. it is reasoned, based on our previous findings of mediation of cellular responses by [Gd@C
82 (OH)22 )n nanoparticles, that [Gd@C82 (OH)22 )n may reverse tumor resistance to cisplatin by reactivating the impaired endocytosis of cisplatin-resistant human prostate cancer (CP-r) cells. Here we report that exposure of the CP-r PC-3-luc cells to cisplatin in the presence of nontoxic [Gd@C82 (OH)22 ]n not only decreased the number of surviving CP-r cells but also inhibited growth of the CP-r tumors in athymic nude mice as measured by both optical and MRI. Labeling the CP-r PC-3 cells with transferrin, an endocytotic marker, demonstrated that pretreatment of the CP-PC-3-luc cells with [Gd@C82 (OH)22 ]n enhanced intracellular accumulation of cisplatin and formation of cisplatin-DNA adducts by restoring the defective endocytosis of the CP-r cancer cells. The results suggest that [Gd@C82 (OH)22 ]n nanoparticles overcome tumor resistance to cisplatin by increasing its intracellular accumulation through the mechanism of restoring defective endocytosis. The technology can be extended to other challenges related to multidrug resistance often found in cancer treatments. [ABSTRACT FROM AUTHOR] more...- Published
- 2010
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- View/download PDF
195. Difference in Phototoxicity of Cyclodextrin Complexed Fullerene [(γ-CyD)2/C60] and Its Aggregated Derivatives toward Human Lens Epithelial Cells.
- Author
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Baozhong Zhao, Yu-Ying He, Colin F. Chignell, Jun-Jie Yin, Usha Andley, and Joan E. Roberts
- Published
- 2009
- Full Text
- View/download PDF
196. The scavenging of reactive oxygen species and the potential for cell protection by functionalized fullerene materials.
- Author
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Jun-Jie Yin, Fang Lao, Fu, Peter P., Wamer, Wayne G., Yuliang Zhao, Wang, Paul C., Yang Qiu, Baoyun Sun, Gengmei Xing, Jinquan Dong, Xing-Jie Liang, and Chunying Chen
- Subjects
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BIOMEDICAL materials , *REACTIVE oxygen species , *FULLERENES , *PRECIPITATION scavenging , *MITOCHONDRIAL membranes , *PEROXIDATION , *ETIOLOGY of diseases , *SURFACE chemistry - Abstract
We demonstrated that three different types of water-soluble fullerenes materials can intercept all of the major physiologically relevant ROS. C60(C(COOH)2)2, C60(OH)22, and Gd@C82(OH)22 can protect cells against H2O2-induced oxidative damage, stabilize the mitochondrial membrane potential and reduce intracellular ROS production with the following relative potencies: Gd@C82(OH)22 ≥ C60(OH)22 > C60(C(COOH)2)2. Consistent with their cytoprotective abilities, these derivatives can scavenge the stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH), and the reactive oxygen species (ROS) superoxide radical anion (O2−), singlet oxygen, and hydroxyl radical (HO.), and can also efficiently inhibit lipid peroxidation in vitro. The observed differences in free radical-scavenging capabilities support the hypothesis that both chemical properties, such as surface chemistry induced differences in electron affinity, and physical properties, such as degree of aggregation, influence the biological and biomedical activities of functionalized fullerenes. This represents the first report that different types of fullerene derivatives can scavenge all physiologically relevant ROS. The role of oxidative stress and damage in the etiology and progression of many diseases suggests that these fullerene derivatives may be valuable in vivo cytoprotective and therapeutic agents. [Copyright &y& Elsevier] more...
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- 2009
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197. Disruption of microfilaments by cytochalasin B decreases accumulation of cisplatin in human epidermal carcinoma and liver carcinoma cell lines.
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Xing-Jie Liang, Jun-Jie Yin, Barbara Taylor, Winkovitch, Stephen M., GarWeld, Susan H., Ding-Wu Shen, Gottesman, Michael M., and Aszalos, Adorjan
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CISPLATIN , *ALKYLATING agents , *ANTINEOPLASTIC agents , *CHLORIDES , *CANCER treatment - Abstract
Although cisplatin is a frequently used cancer chemotherapeutic drug, its effectiveness is hindered by the development of resistance in cancer cells. In order to understand the reason(s) for this resistance, the mechanism of uptake of cisplatin into cells must be characterized. While several previous studies showed structural differences between cisplatin-sensitive and resistant cells, the influence of microfilaments, known to affect transport of molecules into cells, and the influence of certain biophysical characteristics of the plasma membrane needed clarification. We show that resistant human epidermal carcinoma (KB-CP20) and liver carcinoma (BEL-7404-CP20) cells become relatively more resistant if their already weak microfilaments are degraded by cytochalasin B treatment (.5–2 μM). The sensitive counterparts of these cells with intact microfilaments are not significantly affected by this treatment. We also show that the “fluidity” of the plasma membrane and the membrane potential of the sensitive and resistant cells studied do not appear to influence the uptake of cisplatin into the cells. Our results suggest that the status of the microfilament system influences the mechanism of uptake of cisplatin into cells. [ABSTRACT FROM AUTHOR] more...
- Published
- 2008
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198. Effects of Metal Ions, Catechins, and Their Interactions on Prostate Cancer.
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Hai-Ning Yu, Sheng-Rong Shen, and Jun-Jie Yin
- Subjects
METAL ions ,CATECHIN ,PROSTATE cancer ,DISEASE risk factors ,DIET ,MEDICAL care ,GREEN tea ,BIOACTIVE compounds ,THERAPEUTICS - Abstract
Prostate cancer is threatening human health heavily, for its causes are related to diet, genetic factors, and lifestyle. Metal ions, which are necessary to our health, are important factors inducing many diseases including prostate cancer in the condition of absence or excess. Epidemiological and laboratory studies provide convincing evidence that green tea prevents and cures prostate cancer. Practically, interactions of catechins, which are the main bioactive components in green tea or GTP, with metal ions have a new aspect to investigate their mechanism in preventing and curing prostate cancer. In the present paper, we summarize some research about the effects of catechins with metal ions related to prostate cancer and their interactions on prostate cancer. [ABSTRACT FROM AUTHOR] more...
- Published
- 2007
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199. Total phenolic contents, chelating capacities, and radical-scavenging properties of black peppercorn, nutmeg, rosehip, cinnamon and oregano leaf
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Lan Su, Jun-Jie Yin, Charles, Denys, Kequan Zhou, Moore, Jeffrey, and Liangli (Lucy) Yu
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SPICES , *CONDIMENTS , *ETHANES , *ALCOHOLS (Chemical class) - Abstract
Black peppercorn, nutmeg, rosehip, cinnamon and oregano leaf were extracted with 50% acetone and 80% methanol, and evaluated for their radical-scavenging activities against cation (ABTS⠐+), DPPH⠐, peroxyl (ORAC) and hydroxyl (HO⠐) radicals. For each extract, total phenolic content (TPC) and chelating activity were also determined. The extracts of all botanical samples showed significant radical-scavenging capacities, TPC and chelating abilities. The 50% acetone extract of cinnamon had the highest ABTS⠐+-scavenging capacity of 1243 μmol TE/g and the greatest ORAC value of 1256 μmol TE/g on a per weight basis. The 50% acetone extracts of black peppercorn and cinnamon showed higher ABTS+-scavenging, ORAC, Fe+2 chelating ability and TPC value, but lower DPPH⠐ value than the corresponding 80% methanol extracts. The 80% methanol extract of nutmeg had greater ABTS+, ORAC and TPC values than the 50% acetone extract. Electronic spin resonance (ESR) measurements demonstrated that cinnamon had the strongest HO⠐-scavenging activities among all the tested botanical materials. These data indicate that black peppercorn, nutmeg, rosehip, cinnamon and oregano leaf may serve as potential dietary sources of natural antioxidants for improving human nutrition and health. The extracting solvent may alter the antioxidant activity measurement for selected botanicals, including spices and herbs. [Copyright &y& Elsevier] more...
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- 2007
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200. ESR determination of the reactions between selected phenolic acids and free radicals or transition metals
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Kequan Zhou, Jun-Jie Yin, and Liangli (Lucy) Yu
- Subjects
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PHENOLIC acids , *TRANSITION metals , *FREE radicals , *CATIONS - Abstract
Five phenolic acids commonly present in wheat grain and fractions were examined and compared for their radical-scavenging properties and chelating capacities. The free radical-scavenging properties were evaluated against 2,2-diphenyl-1-picryhydrazyl radical (DPPH˙), radical cation (ABTS˙+), peroxide radical anion (O2˙- and hydroxyl radical (HO˙), whereas the chelating properties were evaluated against Fe (II) and Cu (II) using spectrophotometric and electron spin resonance measurements. These phenolic acids differed in their abilities to react with and quench HO˙, O2˙-, ABTS˙+ and DPPH˙, as well as their capacities to form chelating complexes with transition metals. 4-Hydroxybenzoic acid had neither free radical-scavenging nor chelating activity under the experimental conditions. Strong structure–activity relationships were observed in the present study. Both substituents on the phenyl ring and the conjugated carbon skeleton may influence the antioxidant properties of phenolic acids. The presence of an additional methoxyl group in the ortho position of the hydroxyl group showed a strong influence on the chelating property of phenolic acids and their radical-scavenging capacity against O2˙-, ABTS˙+ and DPPH˙, but not on their HO˙-scavenging activity. [Copyright &y& Elsevier] more...
- Published
- 2006
- Full Text
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