35 results on '"Chiu SP"'
Search Results
2. Effect of in vivo ozone exposure on in vitro pulmonary alveolar macrophage mobility
- Author
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McAllen, SJ, Chiu, SP, Phalen, RF, and Rasmussen, RE
- Abstract
The effect of in vivo 03exposure on the mobility of pulmonary alveolar macrophages (PAM) in vitro was investigated. Eight randomly selected rats were exposed for 4 h. Four rats were exposed to a dean air (sham) atmosphere, and four to an atmosphere containing 1 ppm 03. PAM were obtained by lung lavage and placed on gold-colloid coated covers!ips. The area cleared of gold particles by migrating PAM after 24, 48, and 72 h was used as an indicator of cell mobility. The number of PAM recoverable by lavage was simitar for both groups (2 X 10s), but the percentage of macrophages that made tracks was significantly smaller with 95% certainty in the 03 group. For sham-exposed and 0-¡-exposed groups, the area cleared by PAM increased as the length of incubation increased, with the area cleared by the sham-exposed group being about 50% greater during each time period. When the two groups were compared statistically at each time point, the probability that they differed was, in each case, greater than 95%. it was concluded that the in vitro mlgratlonal potential of PAM was most likely decreased by in vivo exposure to O © 1981 by Hemisphere Publishing Corporation.
- Published
- 1981
3. Relaxin Modulates the Genomic Actions and Biological Effects of Estrogen in the Myometrium.
- Author
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Tripathy S, Nagari A, Chiu SP, Nandu T, Camacho CV, Mahendroo M, and Kraus WL
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- Female, Animals, Humans, Mice, Receptors, G-Protein-Coupled metabolism, Receptors, G-Protein-Coupled genetics, Phosphorylation drug effects, Ovariectomy, Signal Transduction drug effects, Mice, Inbred C57BL, Myometrium metabolism, Myometrium drug effects, Relaxin pharmacology, Estrogen Receptor alpha metabolism, Estrogen Receptor alpha genetics, Estradiol pharmacology, Estrogens pharmacology
- Abstract
Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)
- Published
- 2024
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4. Development and characterization of recombinant ADP-ribose binding reagents that allow simultaneous detection of mono and poly ADP-ribose.
- Author
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Chiu SP, Camacho CV, and Kraus WL
- Subjects
- Animals, Mice, Rabbits, Poly Adenosine Diphosphate Ribose metabolism, Poly Adenosine Diphosphate Ribose chemistry, Recombinant Proteins metabolism, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins analysis, Goats, ADP-Ribosylation, Protein Processing, Post-Translational, Humans, Adenosine Diphosphate Ribose metabolism
- Abstract
ADP-ribosylation (ADPRylation) is a post-translational modification (PTM) of proteins mediated by the activity of a variety of ADP-ribosyltransferase (ART) enzymes, such as the Poly (ADP-ribose) Polymerase (PARP) family of proteins. This PTM is diverse in both form and biological functions, which makes it a highly interesting modification, but difficult to study due to limitations in reagents available to detect the diversity of ADPRylation. Recently we developed a set of recombinant antibody-like ADP-ribose (ADPR) binding proteins using naturally occurring ADPR binding domains (ARBDs), including macrodomains and WWE domains, functionalized by fusion to the constant "Fc" region of rabbit immunoglobulin. Herein, we present an expansion of this biological toolkit, where we have replaced the rabbit Fc sequence with the sequence from two other species, mouse and goat. These new reagents are based on a previously characterized set of naturally occurring ARBDs with known specificity. Characterization of the new reagents demonstrates that they can be detected in a species-dependent manner by secondary immunological tools, recognize specific ADPR moieties, and can be used for simultaneous detection of mono ADPR and poly ADPR at single-cell resolution in various antibody-based assays. The expansion of this toolkit will allow for more multiplexed assessments of the complexity of ADPRylation biology in many biological systems., Competing Interests: Conflict of interest W. L. Kraus is a founder, consultant, and Science Advisory Board member for ARase Therapeutics, Inc. W. L. Kraus is a co-holder of U.S. Patent 9,599,606 covering the ADPR detection reagents described herein. The rabbit ARBD-Fc fusions have been licensed to and are sold by EMD Millipore., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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5. The trajectory of smoking cessation after treatment and its related factors in Taiwan.
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Lin CH, Wang CY, Chen KF, Chiu SP, Huang WT, and Fan SY
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- Humans, Male, Taiwan epidemiology, Female, Middle Aged, Adult, Longitudinal Studies, Retrospective Studies, Smoking, Tobacco Use Disorder therapy, Tobacco Use Disorder epidemiology, Smoking Cessation Agents therapeutic use, Smoking Cessation methods, Smoking Cessation statistics & numerical data
- Abstract
Smoking has multiple negative effects on health; therefore, the Taiwanese government provides smoking cessation clinics to smokers. This study aimed to explore the trajectory of smoking cessation after smokers received treatment and the variables related to different trajectories. A retrospective longitudinal study was conducted, in which 735 adult smokers who received smoking cessation medications were recruited. The participants' demographic characteristics, chronic diseases, smoking characteristics, and cigarette dependence were collected from chart review. The amount of smoking was collected at baseline, and at 1 week, 1 month, 3 months, and 6 months after treatment. The Proc Traj procedure for group-based modeling and multinomial logistic regression were used for statistical analysis. Three trajectories were identified: early quitters (28.03%), late quitters (11.43%) and reducers (60.54%). Compared with early quitters, reducers were younger and had a higher probability of severe cigarette dependence. Compared with early quitters, late quitters had a higher number of taking smoking cessation medications. The findings revealed that approximately 60% of participants who received smoking cessation treatment could not completely quit smoking, and that age, number of medications taken, and cigarette dependence were significant predictors of different trajectories., (© 2024. The Author(s).)
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- 2024
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6. Determining the Electron Scattering from Interfacial Coulomb Scatterers in Two-Dimensional Transistors.
- Author
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Lee YT, Huang YT, Chiu SP, Wang RT, Taniguchi T, Watanabe K, Sankar R, Liang CT, Wang WH, Yeh SS, and Lin JJ
- Abstract
Two-dimensional (2D) transistors are promising for potential applications in next-generation semiconductor chips. Owing to the atomically thin thickness of 2D materials, the carrier scattering from interfacial Coulomb scatterers greatly suppresses the carrier mobility and hampers transistor performance. However, a feasible method to quantitatively determine relevant Coulomb scattering parameters from interfacial long-range scatterers is largely lacking. Here, we demonstrate a method to determine the Coulomb scattering strength and the density of Coulomb scattering centers in InSe transistors by comprehensively analyzing the low-frequency noise and transport characteristics. Moreover, the relative contributions from long-range and short-range scattering in the InSe transistors can be distinguished. This method is employed to make InSe transistors consisting of various interfaces a model system, revealing the profound effects of different scattering sources on transport characteristics and low-frequency noise. Quantitatively accessing the scattering parameters of 2D transistors provides valuable insight into engineering the interfaces of a wide spectrum of ultrathin-body transistors for high-performance electronics.
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- 2024
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7. Tuning interfacial two-component superconductivity in CoSi 2 /TiSi 2 heterojunctions via TiSi 2 diffusivity.
- Author
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Chiu SP, Mishra V, Li Y, Zhang FC, Kirchner S, and Lin JJ
- Abstract
We report the observation of enhanced interfacial two-component superconductivity possessing a dominant triplet component in nonmagnetic CoSi
2 /TiSi2 superconductor/normal-metal planar heterojunctions. This is accomplished through the detection of odd-frequency spin-triplet even-parity Cooper pairs in the diffusive normal-metal component of T-shaped proximity junctions. We show that by modifying the diffusivity of the normal-metal part, the transition temperature enhancement can be tuned by a factor of up to 2.3 while the upper critical field increases by up to a factor of 20. Our data suggest that the C49 phase of TiSi2 , which is stabilized in confined geometries, underlies this enhancement. These findings are addressed via a Ginzburg-Landau model and the quasi-classical theory. We also relate our findings to the enigmatic 3-K phase reported in Sr2 RuO4 .- Published
- 2023
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8. Perceptions about traditional Chinese medicine use among Chinese breast cancer survivors: A qualitative study.
- Author
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Hung YL, Leung SS, Chiu SP, Li PY, Kan AC, Lo CC, Wong SZ, Luk SL, Lai CC, El Helali A, and Chan WW
- Subjects
- Humans, Female, Medicine, Chinese Traditional psychology, Hong Kong, Survivors, Breast Neoplasms drug therapy, Cancer Survivors
- Abstract
Introduction: An increasing number of breast cancer survivors (BCS) use traditional Chinese medicine (TCM) throughout their cancer journey. There is emerging evidence that TCM is effective in the reducing side effects of chemotherapy. However, qualitative patient-centric and culturally relevant research into TCM use is scant. This qualitative study aimed to explore the use and perceptions of Chinese Hong Kong BCS using TCM., Methods: Participants were recruited from a university hospital and three breast cancer patient groups in Hong Kong. Questionnaires regarding the use of TCM were given to all participants, followed by individual semi-structured interviews on selected BCS to comprehensively understand TCM's use and perceptions. A greater emphasis was placed on the qualitative data., Results: About half of the participants (n = 67, 48.9%) used TCM during their cancer treatment journey, among which almost all (n = 64, 95.5%) had improved symptoms. Sleeping disturbances (n = 58, 86.6%) and fatigue (n = 53, 79.1%) were the two most common symptoms that improved after TCM. Interview data revealed that participants used TCM to satisfy unmet needs that mainstream conventional Western medicine could not fulfil. They wished for a sense of control and better well-being. They expressed improvements in physical and psychological well-being after the use of TCM. Despite existing barriers, including high cost, long duration of treatment, and disapproval from oncologists, most would still recommend TCM to fellow survivors., Conclusions: Chinese Hong Kong BCS who used TCM reported positive experiences. Understanding how BCS perceive and use TCM is important to integrating TCM into survivorship care in this population., (© 2022 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)
- Published
- 2023
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9. Low-defect-density WS 2 by hydroxide vapor phase deposition.
- Author
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Wan Y, Li E, Yu Z, Huang JK, Li MY, Chou AS, Lee YT, Lee CJ, Hsu HC, Zhan Q, Aljarb A, Fu JH, Chiu SP, Wang X, Lin JJ, Chiu YP, Chang WH, Wang H, Shi Y, Lin N, Cheng Y, Tung V, and Li LJ
- Abstract
Two-dimensional (2D) semiconducting monolayers such as transition metal dichalcogenides (TMDs) are promising channel materials to extend Moore's Law in advanced electronics. Synthetic TMD layers from chemical vapor deposition (CVD) are scalable for fabrication but notorious for their high defect densities. Therefore, innovative endeavors on growth reaction to enhance their quality are urgently needed. Here, we report that the hydroxide W species, an extremely pure vapor phase metal precursor form, is very efficient for sulfurization, leading to about one order of magnitude lower defect density compared to those from conventional CVD methods. The field-effect transistor (FET) devices based on the proposed growth reach a peak electron mobility ~200 cm
2 /Vs (~800 cm2 /Vs) at room temperature (15 K), comparable to those from exfoliated flakes. The FET device with a channel length of 100 nm displays a high on-state current of ~400 µA/µm, encouraging the industrialization of 2D materials., (© 2022. The Author(s).)- Published
- 2022
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10. Oncohistone Mutations Occur at Functional Sites of Regulatory ADP-Ribosylation.
- Author
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Huang D, Camacho CV, Martire S, Nagari A, Setlem R, Gong X, Edwards AD, Chiu SP, Banaszynski LA, and Kraus WL
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- ADP-Ribosylation genetics, Acetylation, Animals, Humans, Mice, Mutation, Proteomics, Histones metabolism, Neoplasms genetics
- Abstract
Recent studies have identified cancer-associated mutations in histone genes that lead to the expression of mutant versions of core histones called oncohistones. Many oncohistone mutations occur at Asp and Glu residues, two amino acids known to be ADP-ribosylated (ADPRylated) by PARP1. We screened 25 Glu or Asp oncohistone mutants for their effects on cell growth in breast and ovarian cancer cells. Ectopic expression of six mutants of three different core histones (H2B, H3, and H4) altered cell growth in at least two different cell lines. Two of these sites, H2B-D51 and H4-D68, were indeed sites of ADPRylation in wild-type (unmutated) histones, and mutation of these sites inhibited ADPRylation. Mutation of H2B-D51 dramatically altered chromatin accessibility at enhancers and promoters, as well as gene expression outcomes, whereas mutation of H4-D68 did not. Additional biochemical, cellular, proteomic, and genomic analyses demonstrated that ADPRylation of H2B-D51 inhibits p300-mediated acetylation of H2B at many Lys residues. In breast cancer cell xenografts in mice, H2B-D51A promoted tumor growth, but did not confer resistance to the cytotoxic effects of PARP inhibition. Collectively, these results demonstrate that functional Asp and Glu ADPRylation sites on histones are mutated in cancers, allowing cancer cells to escape the growth-regulating effects of post-translational modifications via distinct mechanisms., Significance: This study identifies cancer-driving mutations in histones as sites of PARP1-mediated ADP-ribosylation in breast and ovarian cancers, providing a molecular pathway by which cancers may subvert the growth-regulating effects of PARP1., (©2022 American Association for Cancer Research.)
- Published
- 2022
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11. Exploring Usability and Patient Attitude towards a Smart Hospital Service with the Technology Acceptance Model.
- Author
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Tu JC, Luo SC, Lee YL, Shih MF, and Chiu SP
- Subjects
- Humans, Public Health, Surveys and Questionnaires, Technology, Hospitals, Intention
- Abstract
The demand for health care has increased with the development of global technology and the rise of public health awareness, and smart service systems have also been introduced to medical care to relieve the pressure on hospital staff. However, the survey found that patients' willingness to use smart services at the time of consultation has not improved. The main research purpose of this study was to understand the willingness of patients from various groups to use smart medical service systems and to explore the influencing factors on patients' use of smart service systems in hospitals through the technology acceptance model. This study distributed questionnaires in the outpatient area of National Taiwan University Hospital Yunlin Branch, and a total of 202 valid questionnaires were obtained. After related research and regression analysis, it was found that patients paid more attention to the benefits and convenience brought by smart services. If patients believed that smart services were trustworthy and beneficial to themselves, their usage intention and attitude would be positive. The results of this study are summarized by the following four points: (1) Designed according to the cultural conditions of different regions; (2) think about design from the patient's perspective; (3) strengthen the explanation and promotion of smart services; and (4) add humanized care and design. This study could be used as a reference for hospitals to improve their service quality and systems in the future.
- Published
- 2022
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12. Observation of triplet superconductivity in CoSi 2 /TiSi 2 heterostructures.
- Author
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Chiu SP, Tsuei CC, Yeh SS, Zhang FC, Kirchner S, and Lin JJ
- Abstract
Unconventional superconductivity and, in particular, triplet superconductivity have been front and center of topological materials and quantum technology research. Here, we report our observation of triplet pairing in nonmagnetic CoSi
2 /TiSi2 heterostructures on silicon. CoSi2 undergoes a sharp superconducting transition at a critical temperature Tc ≃ 1.5 K, while TiSi2 is a normal metal. We investigate conductance spectra of both two-terminal CoSi2 /TiSi2 contact junctions and three-terminal T-shaped CoSi2 /TiSi2 superconducting proximity structures. Below Tc , we observe (i) a narrow zero-bias conductance peak on top of a broad hump, accompanied by two symmetric side dips in the contact junctions, (ii) a narrow zero-bias conductance peak in T-shaped structures, and (iii) hysteresis in the junction magnetoresistance. These three independent and complementary observations point to chiral p-wave pairing in CoSi2 /TiSi2 heterostructures. The excellent fabrication compatibility of CoSi2 and TiSi2 with present-day silicon-based integrated-circuit technology suggests their potential use in scalable quantum-computing devices., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)- Published
- 2021
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13. Detecting Effects of Low Levels of FCCP on Stem Cell Micromotion and Wound-Healing Migration by Time-Series Capacitance Measurement.
- Author
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Wang SH, Tung TH, Chiu SP, Chou HY, Hung YH, Lai YT, Lee YW, Lee SP, and Lo CM
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- Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone, Electric Impedance, Humans, Mitochondria, Stem Cells, Wound Healing
- Abstract
Electric cell-substrate impedance sensing (ECIS) has been used as a real-time impedance-based method to quantify cell behavior in tissue culture. The method is capable of measuring both the resistance and capacitance of a cell-covered microelectrode at various AC frequencies. In this study, we demonstrate the application of high-frequency capacitance measurement (f = 40 or 64 kHz) for the sensitive detection of both the micromotion and wound-healing migration of human mesenchymal stem cells (hMSCs). Impedance measurements of cell-covered electrodes upon the challenge of various concentrations of carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), from 0.1 to 30 μM, were conducted using ECIS. FCCP is an uncoupler of mitochondrial oxidative phosphorylation (OXPHOS), thereby reducing mitochondrial ATP production. By numerically analyzing the time-series capacitance data, a dose-dependent decrease in hMSC micromotion and wound-healing migration was observed, and the effect was significantly detected at levels as low as 0.1 μM. While most reported works with ECIS use the resistance/impedance time series, our results suggest the potential use of high-frequency capacitance time series for assessing migratory cell behavior such as micromotion and wound-healing migration.
- Published
- 2021
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14. Electrochemical Assessment of Anticancer Compounds on the Human Tongue Squamous Carcinoma Cells.
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Huang CC, Tung TH, Huang CC, Lin SY, Chao SC, Chiu SP, Lee SP, and Lo CM
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- Apoptosis, Cell Line, Tumor, Electrochemistry, Humans, Tongue, Antineoplastic Agents pharmacology, Carcinoma, Squamous Cell drug therapy, Cisplatin pharmacology, Mouth Neoplasms
- Abstract
The most common oral cancer is squamous cell carcinoma (SCC) and its highest occurrence is in the tongue. Almost 30% of patients with one primary head and neck tumor will have a second primary malignancy. In recent studies, two novel plant extracts, andrographolide and cannabidiol (CBD), have been exploited for their anticancer effects. Here, we investigated the cytotoxic effects of these two compounds on SCC-25 cells, a human tongue squamous carcinoma cell line, and compared the outcomes with two chemotherapeutic drugs, cisplatin and fluorouracil. Electric cell substrate impedance sensing (ECIS) system was applied to measure frequency- and time-dependent impedance of SCC-25 cell-covered electrodes and to further assess subtle changes in cell morphology and micromotion in response to different concentrations (0, 10, 30, 100, and 300 µM) of these compounds. AlamarBlue and Annexin V/7-AAD binding assays were used to measure the concentration dependent changes in viability and apoptosis of SCC-25 cells. Our results demonstrate that 24 hours after exposure to 30 µM CBD can significantly decrease the micromotion rate, damage the integrity of cell morphology, reduce cell viability, and induce higher apoptosis in treated SCC-25 cells, while the other three drugs attain similar effects at the concentration of 100 µM or higher. The apoptosis-induced changes in cell morphology and micromotion monitored by ECIS correlate well with biochemical assays. Thus, both frequency- and time-dependent impedance measurements using ECIS can be used to real-time follow cancer cell activities in response to anticancer drugs with different temporal cytotoxicity profiles.
- Published
- 2020
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15. Author Correction: Angiotensin-converting enzyme inhibitors or angiotensin receptor blocker monotherapy retard deterioration of renal function in Taiwanese chronic kidney disease population.
- Author
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Zheng CM, Wang JY, Chen TT, Wu YC, Wu YL, Lin HT, Chiu SP, Chang TJ, Zheng JQ, Chu NF, Lin YM, Su SL, Lu KC, Chen JS, Sung FC, Lee CT, Yang Y, Hwang SJ, Wang MC, Hsu YH, Chiou HY, Kao S, Wu MY, and Lin YF
- Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
- Published
- 2020
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16. The gene structure and hypervariability of the complete Penaeus monodon Dscam gene.
- Author
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Apitanyasai K, Huang SW, Ng TH, He ST, Huang YH, Chiu SP, Tseng KC, Lin SS, Chang WC, Baldwin-Brown JG, Long AD, Lo CF, Yu HT, and Wang HC
- Subjects
- Amino Acid Sequence, Animals, Hemocytes metabolism, Nerve Tissue metabolism, Phylogeny, Sequence Homology, Whole Genome Sequencing, Alternative Splicing, Arthropod Proteins genetics, Exons, Penaeidae genetics
- Abstract
Using two advanced sequencing approaches, Illumina and PacBio, we derive the entire Dscam gene from an M2 assembly of the complete Penaeus monodon genome. The P. monodon Dscam (PmDscam) gene is ~266 kbp, with a total of 44 exons, 5 of which are subject to alternative splicing. PmDscam has a conserved architectural structure consisting of an extracellular region with hypervariable Ig domains, a transmembrane domain, and a cytoplasmic tail. We show that, contrary to a previous report, there are in fact 26, 81 and 26 alternative exons in N-terminal Ig2, N-terminal Ig3 and the entirety of Ig7, respectively. We also identified two alternatively spliced exons in the cytoplasmic tail, with transmembrane domains in exon variants 32.1 and 32.2, and stop codons in exon variants 44.1 and 44.2. This means that alternative splicing is involved in the selection of the stop codon. There are also 7 non-constitutive cytoplasmic tail exons that can either be included or skipped. Alternative splicing and the non-constitutive exons together produce more than 21 million isoform combinations from one PmDscam locus in the P. monodon gene. A public-facing database that allows BLAST searches of all 175 exons in the PmDscam gene has been established at http://pmdscam.dbbs.ncku.edu.tw/ .
- Published
- 2019
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17. Selective expression of a "correct cloud" of Dscam in crayfish survivors after second exposure to the same pathogen.
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Ng TH, Kumar R, Apitanyasai K, He ST, Chiu SP, and Wang HC
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- Animals, Arthropod Proteins genetics, Astacoidea virology, Cell Adhesion Molecules genetics, Protein Isoforms genetics, Protein Isoforms immunology, Random Allocation, Arthropod Proteins immunology, Astacoidea physiology, Cell Adhesion Molecules immunology, White spot syndrome virus 1 physiology
- Abstract
Arthropod hypervariable Dscam (Down syndrome cell adhesion molecule) may be involved in adaptive-like immune characteristics, namely immune priming, enabling the host to "learn" and "remember" pathogens previously encountered in arthropods. However, expression of Dscam in immune-primed arthropods after a second challenge has apparently not been confirmed. Herein, working with Dscam of Australian freshwater crayfish (Cherax quadricarinatus, i.e. CqDscam), we further investigated whether immune priming is mediated by "clouds" of appropriate (or "correct") CqDscam isoforms. In crayfish that survived a first WSSV challenge (immune priming), long-lasting CqDscam expression remained higher after a second WSSV challenge. Selective CqDscam isoforms were also induced after both challenges. Based on pathogen binding assays, these WSSV-induced CqDscam isoforms had a higher WSSV binding ability, perhaps mainly mediated by Ig3-spliced variants. We therefore hypothesized that in these crayfish survivors, an unknown selection process was generating a "correct cloud" of CqDscam against a previously encountered pathogen., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2019
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18. Application of ECIS to Assess FCCP-Induced Changes of MSC Micromotion and Wound Healing Migration.
- Author
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Chiu SP, Lee YW, Wu LY, Tung TH, Gomez S, Lo CM, and Wang JY
- Subjects
- Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone pharmacology, Cell Adhesion drug effects, Cell Movement drug effects, Humans, Mitochondria drug effects, Cell Culture Techniques, Electric Impedance, Mesenchymal Stem Cells drug effects, Wound Healing drug effects
- Abstract
Electric cell-substrate impedance sensing (ECIS) is an emerging technique for sensitively monitoring morphological changes of adherent cells in tissue culture. In this study, human mesenchymal stem cells (hMSCs) were exposed to different concentrations of carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) for 20 h and their subsequent concentration-dependent responses in micromotion and wound healing migration were measured by ECIS. FCCP disrupts ATP synthesis and results in a decrease in cell migration rates. To detect the change of cell micromotion in response to FCCP challenge, time-series resistances of cell-covered electrodes were monitored and the values of variance were calculated to verify the difference. While Seahorse XF-24 extracellular flux analyzer can detect the effect of FCCP at 3 μM concentration, the variance calculation of the time-series resistances measured at 4 kHz can detect the effect of FCCP at concentrations as low as 1 μM. For wound healing migration, the recovery resistance curves were fitted by sigmoid curve and the hill slope showed a concentration-dependent decline from 0.3 μM to 3 μM, indicating a decrease in cell migration rate. Moreover, dose dependent incline of the inflection points from 0.3 μM to 3 μM FCCP implied the increase of the half time for wound recovery migration. Together, our results demonstrate that partial uncoupling of mitochondrial oxidative phosphorylation reduces micromotion and wound healing migration of hMSCs. The ECIS method used in this study offers a simple and sensitive approach to investigate stem cell migration and its regulation by mitochondrial dynamics.
- Published
- 2019
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19. Application of Electric Cell-Substrate Impedance Sensing to Investigate the Cytotoxic Effects of Andrographolide on U-87 MG Glioblastoma Cell Migration and Apoptosis.
- Author
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Chiu SP, Batsaikhan B, Huang HM, and Wang JY
- Subjects
- Apoptosis drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Diterpenes pharmacology, Electric Impedance, Gene Expression Regulation, Neoplastic drug effects, Glioblastoma pathology, Humans, Proto-Oncogene Proteins c-bcl-2 genetics, Temozolomide pharmacology, Vorinostat pharmacology, Biosensing Techniques, Cell Movement drug effects, Cell Survival drug effects, Glioblastoma drug therapy
- Abstract
Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults. In recent studies, the efficacy of suberoylanilide hydroxamic acid (SAHA) has been investigated for GBM. We explored the effects of two exploratory compounds, the histone deacetylase SAHA and the natural product andrographolide, on Uppsala 87 Malignant Glioma (U-87 MG) cell migration and viability in comparison with the clinically used therapeutic agent temozolomide (TMZ). We used the electric cell-substrate impedance sensing (ECIS) system to monitor the migration of U-87 MG cells after treatment with various concentrations of these compounds. Moreover, we used the Alamar blue assay and western blotting to observe the concentration-dependent changes in the viability and apoptosis of U-87 MG cells. Our results demonstrated that both SAHA and andrographolide (10-300 μM) significantly inhibited GBM cell migration in a concentration-dependent manner, and 10 μM SAHA and 56 μM andrographolide demonstrated remarkable inhibitory effects on U-87 MG migration. Western blotting indicated that compared with TMZ, both SAHA and andrographolide induced higher expression levels of apoptosis-related proteins, such as caspase-3, BAX, and PARP in U-87 MG cells. Furthermore, all three drugs downregulated the expression of the antiapoptotic protein Bcl-2. In conclusion, SAHA and andrographolide showed exceptional results in inhibiting cell migration and motility. The ECIS wound healing assay is a powerful technique to identify and screen potential therapeutic agents that can inhibit cancer cell migration., Competing Interests: The authors declare no conflict of interest.
- Published
- 2019
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20. Angiotensin-converting enzyme inhibitors or angiotensin receptor blocker monotherapy retard deterioration of renal function in Taiwanese chronic kidney disease population.
- Author
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Zheng CM, Wang JY, Chen TT, Wu YC, Wu YL, Lin HT, Chiu SP, Chang TJ, Zheng JQ, Chu NF, Lin YM, Su SL, Lu KC, Chen JS, Sung FC, Lee CT, Yang Y, Hwang SJ, Wang MC, Hsu YH, Chiou HY, Kao S, Wu MY, and Lin YF
- Subjects
- Aged, Female, Glomerular Filtration Rate drug effects, Humans, Hypertension blood, Hypertension drug therapy, Hypertension physiopathology, Kidney drug effects, Kidney metabolism, Longitudinal Studies, Male, Middle Aged, Odds Ratio, Phosphates blood, Prospective Studies, Renal Insufficiency, Chronic blood, Renal Insufficiency, Chronic physiopathology, Taiwan, Triglycerides blood, Angiotensin Receptor Antagonists therapeutic use, Angiotensin-Converting Enzyme Inhibitors therapeutic use, Renal Insufficiency, Chronic drug therapy
- Abstract
It remains unclear how different uses of angiotensin-converting inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) influence the progression of chronic kidney disease (CKD). This study explored CKD progression in a multicentre, longitudinal cohort study that included 2639 patients with CKD stage 1-5 and hypertension. Patients treated with ACEI or ARB for ≥90 days during a 6-mo period comprised the study group, or no treatment, comprised the control group. The study group was subdivided on the basis of treatment: ACEI monotherapy or ARB monotherapy. Progression of renal deterioration was defined by an average eGFR decline of more than 5 mL/min/1.73 m
2 /yr or the commencement of dialysis. With at least 1-year follow up, a progression of renal deterioration was demonstrated in 29.70% of the control group and 25.09% of the study group. Patients in the study group had significantly reduced progression of CKD with adjusted odds ratio 0.79 (95% confidence interval: 0.63-0.99). However, when ACEI monotherapy and ARB monotherapy were analyzed separately, none of their associations with CKD progression was statistically significant. In conclusion, ACEI or ARB monotherapy may retard the deterioration of renal function among patients with CKD and hypertension.- Published
- 2019
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21. Ultralow 1/f Noise in a Heterostructure of Superconducting Epitaxial Cobalt Disilicide Thin Film on Silicon.
- Author
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Chiu SP, Yeh SS, Chiou CJ, Chou YC, Lin JJ, and Tsuei CC
- Abstract
High-precision resistance noise measurements indicate that the epitaxial CoSi
2 /Si heterostructures at 150 and 2 K (slightly above its superconducting transition temperature Tc of 1.54 K) exhibit an unusually low 1/f noise level in the frequency range of 0.008-0.2 Hz. This corresponds to an upper limit of Hooge constant γ ≤ 3 × 10-6 , about 100 times lower than that of single-crystalline aluminum films on SiO2 capped Si substrates. Supported by high-resolution cross-sectional transmission electron microscopy studies, our analysis reveals that the 1/f noise is dominated by excess interfacial Si atoms and their dimer reconstruction induced fluctuators. Unbonded orbitals (i.e., dangling bonds) on excess Si atoms are intrinsically rare at the epitaxial CoSi2 /Si(100) interface, giving limited trapping-detrapping centers for localized charges. With its excellent normal-state properties, CoSi2 has been used in silicon-based integrated circuits for decades. The intrinsically low noise properties discovered in this work could be utilized for developing quiet qubits and scalable superconducting circuits for future quantum computing.- Published
- 2017
- Full Text
- View/download PDF
22. Edge-termination and core-modification effects of hexagonal nanosheet graphene.
- Author
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Deng JP, Chen WH, Chiu SP, Lin CH, and Wang BC
- Subjects
- Hydroxides chemistry, Models, Chemical, Oxides chemistry, Electrons, Graphite chemistry, Nanostructures chemistry
- Abstract
Optimized geometries and electronic structures of two different hexagonal grapheme nanosheets (HGNSs), with armchair (n-A-HGNS, n = 3-11) and zigzag (n-Z-HGNS, n = 1-8) edges have been calculated by using the GGA/PBE method implemented in the SIESTA package, with the DZP basis set, where n represents the number of peripheral rings. The computed HOMO-LUMO energy gap (Eg = ELUMO - EHOMO) decreases for fully H-terminated A- and Z-HGNSs with increasing n, i.e., with increasing nanosheet size and pπ-orbitals being widely delocalized over the sheet surface. The full terminations, calculated with various functional groups, including the electron-withdrawing (F-, Cl-, and CN-) and -donating (OH-, and SH-) substitutions, were addressed. Significant lowering of EHOMO and ELUMO was obtained for CN-terminated HGNS as compared to those for H-terminated ones due to the mesomeric effect. The calculated Eg value decreases with increasing n for all terminations, whereby for the SH-termination in HGNS, the termination effect becomes less significant with increasing n. Further, the calculation results for stabilities of HGNS oxides support the tendency toward the oxidative reactivity at the edge site of the sheet, which shows most pronounced C-C bond length alternation, by chemical modification. Physical properties of HGNSs with various numbers of the core-defects, which can be obtained by strong oxidation, were also investigated. Their structures can change drastically from planar to saddle-like shapes. These conformations could be used as stationary phases with controlled interaction in the separation methods such as HPLC and the other chemical analysis techniques.
- Published
- 2014
- Full Text
- View/download PDF
23. Neurotrophic action of 5-hydroxylated polymethoxyflavones: 5-demethylnobiletin and gardenin A stimulate neuritogenesis in PC12 cells.
- Author
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Chiu SP, Wu MJ, Chen PY, Ho YR, Tai MH, Ho CT, and Yen JH
- Subjects
- Animals, Biomarkers metabolism, Citrus chemistry, Fruit chemistry, Gene Expression Regulation drug effects, MAP Kinase Signaling System drug effects, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Neurites metabolism, Neurons metabolism, PC12 Cells, Rats, Flavones metabolism, Flavones pharmacology, Neurites drug effects, Neurogenesis drug effects, Neurons drug effects, Nootropic Agents pharmacology
- Abstract
Polymethoxyflavones (PMFs) exhibit a broad spectrum of biological properties, including anticancer, antiatherogenic, and neuroprotective effects. The aim of this study is to investigate the neurotrophic effects of 5-demethylnobiletin, a hydroxylated PMF found in citrus plants, and gardenin A, a synthetic PMF analogue, on neurite outgrowth and neuronal differentiation in PC12 cells. The results of this study showed that 5-demethylnobiletin and gardenin A (10-20 μM) potently induce neurite outgrowth in PC12 cells, accompanied by the expression of neuronal differentiation and synapse formation marker proteins, growth-associated protein-43 (GAP-43), and synaptophysin. We observed that the addition of K252a, a TrKA antagonist, significantly inhibited NGF-induced neurite outgrowth in PC12 cells, but 5-demethylnobiletin- or gardenin A-induced neurite outgrowth was not affected. Treatment with 5-demethylnobiletin and gardenin A markedly induced the phosphorylation of both cyclic AMP response element-binding protein (CREB) and CRE-mediated transcription, which was suppressed through the administration of the inhibitor 2-naphthol AS-E phosphate (KG-501) or using CREB siRNA. Furthermore, our results showed that MAPK/ERK kinase 1/2 (MEK1/2), protein kinase A (PKA), and protein kinase C (PKC) inhibitors blocked the CRE transcription activity and neurite outgrowth induced through 5-demethylnobiletin or gardenin A. Consistently, increased ERK phosphorylation and PKA and PKC activities were observed in PC12 cells treated with 5-demethylnobiletin or gardenin A. These results reveal for the first time that 5-demethylnobiletin and gardenin A promote neuritogenesis through the activation of MAPK/ERK-, PKC-, and PKA-dependent, but not TrkA-dependent, CREB signaling pathways in PC12 cells.
- Published
- 2013
- Full Text
- View/download PDF
24. The antecedents of buyers' perceived justice in online markets.
- Author
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Chiu SP, Chou HW, and Chiu CM
- Subjects
- Consumer Behavior statistics & numerical data, Cross-Sectional Studies, Female, Humans, Male, Surveys and Questionnaires, Trust psychology, Commerce standards, Internet standards, Social Justice psychology
- Abstract
The success of a business largely depends upon customers' intentions to continue to purchase, but this can be a challenge for vendors in online markets. This study proposes a model which identifies an initial set of justice antecedents and evaluates their relation to perceived justice, trust, and repurchase intention in online markets. The theoretical model is tested by using structural equation modeling on a data set of 424 buyers in Yahoo! Kimo online auction market. The results demonstrate that three dimensions of justice (distributive, procedural, and interactional) are positively and significantly related to trust, which in turn affects buyers' intention to repurchase. Moreover, among the three dimensions of justice judgments, distributive justice and interactional justice are relatively more important than procedural justice in predicting buyers' trust in sellers. In terms of the antecedents of justice, this study provides evidence that product quality and delivery performance are significantly related to distributive justice, while information quality and contact channel are important antecedents of procedural justice. This study also finds that responsiveness is important in enhancing buyers' judgments of interactional justice.
- Published
- 2013
- Full Text
- View/download PDF
25. Quantum-interference transport through surface layers of indium-doped ZnO nanowires.
- Author
-
Chiu SP, Lu JG, and Lin JJ
- Abstract
We have fabricated indium-doped ZnO (IZO) nanowires (NWs) and carried out four-probe electrical-transport measurements on two individual NWs with geometric diameters of ≈70 and ≈90 nm in a wide temperature T interval of 1-70 K. The NWs reveal overall charge conduction behavior characteristic of disordered metals. In addition to the T dependence of resistance R, we have measured the magnetoresistance (MR) in magnetic fields applied either perpendicular or parallel to the NW axis. Our R(T) and MR data in different T intervals are consistent with the theoretical predictions of the one- (1D), two- (2D) or three-dimensional (3D) weak-localization (WL) and the electron-electron interaction (EEI) effects. In particular, a few dimensionality crossovers in the two effects are observed. These crossover phenomena are consistent with the model of a 'core-shell-like structure' in individual IZO NWs, where an outer shell of thickness t (~15-17 nm) is responsible for the quantum-interference transport. In the WL effect, as the electron dephasing length Lφ gradually decreases with increasing T from the lowest measurement temperatures, a 1D-to-2D dimensionality crossover takes place around a characteristic temperature where Lφ approximately equals d, an effective NW diameter which is slightly smaller than the geometric diameter. As T further increases, a 2D-to-3D dimensionality crossover occurs around another characteristic temperature where Lφ approximately equals t (
- Published
- 2013
- Full Text
- View/download PDF
26. Luteolin induces microRNA-132 expression and modulates neurite outgrowth in PC12 cells.
- Author
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Lin LF, Chiu SP, Wu MJ, Chen PY, and Yen JH
- Subjects
- Animals, Cell Line, Cyclic AMP Response Element-Binding Protein metabolism, Enzyme Inhibitors pharmacology, Extracellular Signal-Regulated MAP Kinases metabolism, MicroRNAs genetics, Phosphorylation drug effects, Rats, Signal Transduction drug effects, Luteolin pharmacology, MicroRNAs metabolism, Neurites drug effects
- Abstract
Luteolin (3',4',5,7-tetrahydroxyflavone), a food-derived flavonoid, has been reported to exert neurotrophic properties that are associated with its capacity to promote neuronal survival and neurite outgrowth. In this study, we report for the first time that luteolin induces the persistent expression of microRNA-132 (miR-132) in PC12 cells. The correlation between miR-132 knockdown and a decrease in luteolin-mediated neurite outgrowth may indicate a mechanistic link by which miR-132 functions as a mediator for neuritogenesis. Furthermore, we find that luteolin led to the phosphorylation and activation of cAMP response element binding protein (CREB), which is associated with the up-regulation of miR-132 and neurite outgrowth. Moreover, luteolin-induced CREB activation, miR-132 expression and neurite outgrowth were inhibited by adenylate cyclase, protein kinase A (PKA) and MAPK/ERK kinase 1/2 (MEK1/2) inhibitors but not by protein kinase C (PKC) or calcium/calmodulin-dependent protein kinase II (CaMK II) inhibitors. Consistently, we find that luteolin treatment increases ERK phosphorylation and PKA activity in PC12 cells. These results show that luteolin induces the up-regulation of miR-132, which serves as an important regulator for neurotrophic actions, mainly acting through the activation of cAMP/PKA- and ERK-dependent CREB signaling pathways in PC12 cells.
- Published
- 2012
- Full Text
- View/download PDF
27. Acute intravenous injection toxicity of BMEDA in mice.
- Author
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Chang CH, Chiu SP, Chiang TC, and Lee TW
- Subjects
- Animals, Ethylenediamines administration & dosage, Female, Injections, Intravenous, Lethal Dose 50, Liposomes, Male, Mice, Mice, Inbred ICR, Organometallic Compounds administration & dosage, Radiopharmaceuticals administration & dosage, Toxicity Tests, Acute, Ethylenediamines toxicity, Organometallic Compounds toxicity, Radiopharmaceuticals toxicity
- Abstract
(188)Re/(186)Re-N,N-bis(2-mercaptoethyl)-N',N'-diethylethylenediamine-labeled pegylated liposome ((188)Re-BMEDA-liposome) has been proven as a promising candidate for cancer therapy in tumor-rodent models. (188)Re-BMEDA complexes should be prepared for the radiolabeling of liposomes. This article describes the acute toxicity of BMEDA in Imprinting Control Region (ICR) mice. Treated mice were administered with BMEDA at dose levels of 3, 6, 9, and 12 mg/kg, with a dose volume of 10 mL/kg. The control mice were administered 10 mL/kg of vehicle control. The mice were observed for 14 days. Observations included mortality, clinical signs, total body-weight gains, food consumption, and gross necropsy findings. BMEDA exerted no adverse toxic effects in ICR mice at dose levels 3 mg/kg, which are up to 360,000 times higher than the intended human dose. The lethal-dose (LD(50)) value of BMEDA was 8.13 and 8.68 mg/kg in male and female mice, respectively.
- Published
- 2011
- Full Text
- View/download PDF
28. Neurotrophic effect of citrus 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone: promotion of neurite outgrowth via cAMP/PKA/CREB pathway in PC12 cells.
- Author
-
Lai HC, Wu MJ, Chen PY, Sheu TT, Chiu SP, Lin MH, Ho CT, and Yen JH
- Subjects
- Animals, Cell Shape drug effects, Enzyme Activation drug effects, Flavones chemistry, GAP-43 Protein genetics, GAP-43 Protein metabolism, Gene Expression Regulation drug effects, Models, Biological, Naphthols pharmacology, Nerve Growth Factors chemistry, Neurites drug effects, Organophosphates pharmacology, PC12 Cells, Phosphorylation drug effects, RNA, Messenger genetics, RNA, Messenger metabolism, Rats, Receptor, trkA metabolism, Signal Transduction drug effects, Citrus chemistry, Cyclic AMP metabolism, Cyclic AMP Response Element-Binding Protein metabolism, Cyclic AMP-Dependent Protein Kinases metabolism, Flavones pharmacology, Nerve Growth Factors pharmacology, Neurites metabolism
- Abstract
5-Hydroxy-3,6,7,8,3',4'-hexamethoxyflavone (5-OH-HxMF), a hydroxylated polymethoxyflavone, is found exclusively in the Citrus genus, particularly in the peels of sweet orange. In this research, we report the first investigation of the neurotrophic effects and mechanism of 5-OH-HxMF in PC12 pheochromocytoma cells. We found that 5-OH-HxMF can effectively induce PC12 neurite outgrowth accompanied with the expression of neuronal differentiation marker protein growth-associated protein-43(GAP-43). 5-OH-HxMF caused the enhancement of cyclic AMP response element binding protein (CREB) phosphorylation, c-fos gene expression and CRE-mediated transcription, which was inhibited by 2-naphthol AS-E phosphate (KG-501), a specific antagonist for the CREB-CBP complex formation. Moreover, 5-OH-HxMF-induced both CRE transcription activity and neurite outgrowth were inhibited by adenylate cyclase and protein kinase A (PKA) inhibitor, but not MEK1/2, protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K) or calcium/calmodulin-dependent protein kinase (CaMK) inhibitor. Consistently, 5-OH-HxMF treatment increased the intracellular cAMP level and downstream component, PKA activity. We also found that addition of K252a, a TrKA antagonist, significantly inhibited NGF- but not 5-OH-HxMF-induced neurite outgrowth. These results reveal for the first time that 5-OH-HxMF is an effective neurotrophic agent and its effect is mainly through a cAMP/PKA-dependent, but TrKA-independent, signaling pathway coupling with CRE-mediated gene transcription. A PKC-dependent and CREB-independent pathway was also involved in its neurotrophic action.
- Published
- 2011
- Full Text
- View/download PDF
29. Multimodality imaging and preclinical evaluation of 177Lu-AMBA for human prostate tumours in a murine model.
- Author
-
Liu IH, Chang CH, Ho CL, Chiu SP, Lee WC, Chang TJ, Chen LC, Wu YH, Chuang CH, Fu YK, and Lee TW
- Subjects
- Animals, Cell Line, Tumor, Humans, Isotope Labeling, Luminescent Measurements methods, Lutetium, Male, Mice, Mice, SCID, Oligopeptides blood, Prostatic Neoplasms blood, Radioisotopes, Radiopharmaceuticals blood, Tissue Distribution, Tomography, Emission-Computed, Single-Photon methods, Transplantation, Heterologous, Oligopeptides pharmacokinetics, Prostatic Neoplasms diagnostic imaging, Prostatic Neoplasms metabolism, Radiopharmaceuticals pharmacokinetics
- Abstract
AMBA (DO3A-CH(2)CO-G-(4-aminobenzoyl)-QWAVGHLM-NH(2)) is a bombesin (BN)-like peptide having high affinity with gastrin-releasing peptide receptors (GRPr).(177)Lu-AMBA is currently undergoing clinical trial as a systemic radiotherapy for hormone refractory prostate cancer (HRPC) patients. This study evaluated the biodistribution, pharmacokinetics, bioluminescent imaging (BLI) and microSPECT/CT imaging of (177)Lu-AMBA in PC-3M-luc-C6 luciferase-expressing human prostate tumour-bearing mice. Plasma stability of (177)Lu-AMBA could be maintained up to 55.67±6.07% at 24 h in a protection buffer. High positive correlations of PC-3M luc-C6 tumour growth in SCID mice between caliper measurement and BLI were observed (R(2)=0.999). Both the biodistribution and microSPECT/CT imaging in PC-3M-luc-C6 bearing-tumour mice showed that (177)Lu-AMBA in tumour uptake could be retained for 24 h. The distribution half-life (t(1/2α)) and the elimination half-life (t(1/2β)) of (177) Lu-AMBA in mice were 0.52 h and 26.6 h, respectively. These results indicated that BLI could be used to monitor the growth of tumour. High uptake of (177)Lu-AMBA in PC-3M-luc-C6 tumour-bearing mice by microSPECT/CT imaging can further evaluate the potential of (177)Lu-AMBA therapy for PC-3M-luc-C6 tumours.
- Published
- 2010
30. Electrical conduction mechanisms in natively doped ZnO nanowires (II).
- Author
-
Tsai LT, Chiu SP, Lu JG, and Lin JJ
- Abstract
We have measured the intrinsic electrical resistivities, rho(T), of three individual single-crystalline ZnO nanowires (NWs) from 320 down to 1.3 K. The NWs were synthesized via carbon thermal chemical vapor deposition and the four-probe Pt contacting electrodes were made by the focused-ion-beam technique. Analysis of the overall temperature behavior of rho(T) confirms that the charge transport processes in natively doped ZnO NWs are due to a combination of the thermal activation conduction and the nearest-neighbor hopping conduction processes, as proposed and explained in a recent work (Chiu et al 2009 Nanotechnology 20 015203) where the ZnO NWs were grown by a different thermal evaporation method and the four-probe electrodes were made by the electron-beam lithography technique. Taken together, the observations of these two complementary studies firmly establish that the electrical conduction mechanisms in natively doped ZnO NWs are unique and now satisfactorily understood.
- Published
- 2010
- Full Text
- View/download PDF
31. Four-probe electrical-transport measurements on single indium tin oxide nanowires between 1.5 and 300 K.
- Author
-
Chiu SP, Chung HF, Lin YH, Kai JJ, Chen FR, and Lin JJ
- Subjects
- Electric Impedance, Electron Transport, Macromolecular Substances chemistry, Molecular Conformation, Nanostructures ultrastructure, Particle Size, Surface Properties, Temperature, Crystallization methods, Materials Testing methods, Nanostructures chemistry, Nanotechnology methods, Tin Compounds chemistry
- Abstract
Single-crystalline indium tin oxide (ITO) nanowires (NWs) were grown by the standard thermal evaporation method. The as-grown NWs were typically 100-300 nm in diameter and a few microm long. Four-probe submicron Ti/Au electrodes on individual NWs were fabricated by the electron-beam lithography technique. The resistivities of several single NWs have been measured from 300 down to 1.5 K. The results indicate that the as-grown ITO NWs are metallic, but disordered. The overall temperature behavior of resistivity can be described by the Bloch-Grüneisen law plus a low-temperature correction due to the scattering of electrons off dynamic point defects. This observation suggests the existence of numerous dynamic point defects in as-grown ITO NWs.
- Published
- 2009
- Full Text
- View/download PDF
32. Electrical conduction mechanisms in natively doped ZnO nanowires.
- Author
-
Chiu SP, Lin YH, and Lin JJ
- Abstract
Single-crystalline zinc oxide (ZnO) nanowires (NWs) with diameters of 90-200 nm were synthesized by the thermal evaporation method. Four-probe Ti/Au electrodes were made by the standard electron-beam lithography technique, and the intrinsic resistivities, rho(T), of individual NWs were measured over a wide range of temperature from 300 down to 0.25 K. The temperature behavior of rho(T) between 300 and 5 K reveals that the intrinsic electrical-transport mechanisms through individual ZnO NWs are due to a combination of the thermal activation conduction and the nearest-neighbor hopping conduction processes. Three distinct activation and hopping contributions with discrete characteristic activation energies are observed. Above about 100 K, the charge transport mechanism is dominated by the thermal activation of electrons from the Fermi level, mu, to the conduction band. Between approximately 20 and 100 K, the charge transport mechanism is due to the activation of electrons from mu to the upper impurity (D-) band. Between approximately 5 and 20 K, the charge transport mechanism arises from the nearest-neighbor hopping conduction within the lower impurity (D) band. Such unique electrical conduction behaviors can be explained in terms of the intricate material properties (in particular, the presence of moderately high concentrations of n-type defects accompanied with a slight self-compensation) in natively doped ZnO NWs. In one heavily doped NW, a surface-related conduction process manifesting the two-dimensional attributes of quantum-interference transport phenomena is observed. The carrier concentrations in our NWs have been estimated, and they were found to lie close to the critical concentration for the Mott metal-insulator transition.
- Published
- 2009
- Full Text
- View/download PDF
33. Thermal fluctuation-induced tunneling conduction through metal nanowire contacts.
- Author
-
Lin YH, Chiu SP, and Lin JJ
- Abstract
The temperature behavior of how electrons propagate through an insulating electronic contact formed at the interface between a submicron Cr/Au electrode and a metallic RuO(2) nanowire (NW) has been studied between 300 and 1 K. The NWs are typically of ∼70 nm in diameter and a few microns long. The submicron electrodes were fabricated by the standard electron-beam lithography technique. By employing the two-probe method, the electronic contact resistances, R(c)(T), have been determined. We found that, in general, R(c) increases rapidly with decreasing temperature but eventually saturates at liquid-helium temperatures. Such a temperature behavior can be well described by a thermal fluctuation-induced tunneling (FIT) conduction process which considers the crossover feature from thermal activation conduction at high temperatures to simple elastic tunneling conduction at low temperatures. The wide applicability of this FIT model has further been established by employing metallic IrO(2) and Sn-doped In(2)O(3-x) NWs. This work demonstrates that the underlying physics for the charge transport properties of an insulating electronic contact can be well understood.
- Published
- 2008
- Full Text
- View/download PDF
34. A pilot study on the effects of a Chinese herbal preparation on menopausal symptoms.
- Author
-
Chan CC, Lau WN, Chiu SP, Chen LC, Choi WK, and Tang GW
- Subjects
- Estradiol blood, Female, Follicle Stimulating Hormone blood, Hong Kong, Humans, Luteinizing Hormone blood, Menopause physiology, Middle Aged, Pilot Projects, Drugs, Chinese Herbal administration & dosage, Menopause drug effects
- Abstract
This study was conducted to determine whether a particular Chinese medicinal preparation is effective in alleviating menopausal symptoms. Chinese women with menopausal symptoms were recruited to receive treatment for 3 months followed by 3 months without treatment. The severity of menopausal symptoms and serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol levels were assessed at baseline, 3 and 6 months. Data from 97 women with a mean age of 52.3 years were analyzed. Sixty women (62%) were postmenopausal. The serum FSH level (interquartile range) was 58.0 (39.5-72.4) IU/l at baseline and rose significantly 3 months after treatment. The difference remained significant in the postmenopausal group while there was no significant difference in the perimenopausal women. The changes in serum LH and estradiol levels remained unchanged. The baseline menopausal symptom score was 8.9 +/- 6.0. The menopausal symptom score improved markedly after treatment and remained at the same level at 6 months. All individual menopausal symptoms improved significantly after 3 months of treatment except dry eye. Most of these symptoms remained significantly improved at 6 months compared with the pre-treatment assessment. We observed that the Chinese medicinal preparation used in this study is effective in improving menopausal symptoms in healthy Chinese women. Further randomized controlled trial will be needed to confirm this observation.
- Published
- 2006
- Full Text
- View/download PDF
35. Effect of in vivo ozone exposure on in vitro pulmonary alveolar macrophage mobility.
- Author
-
McAllen SJ, Chiu SP, Phalen RF, and Rasmussen RE
- Subjects
- Animals, Cell Movement drug effects, Gold metabolism, In Vitro Techniques, Macrophages metabolism, Male, Rats, Rats, Inbred Strains, Macrophages drug effects, Ozone toxicity, Pulmonary Alveoli drug effects
- Abstract
The effect of in vivo O3 exposure on the mobility of pulmonary alveolar macrophages (PAM) in vitro was investigated. Eight randomly selected rats were exposed for 4 h. Four rats were exposed to a clean air (sham) atmosphere, and four to an atmosphere containing 1ppm O3. PAM were obtained by lung lavage and placed on gold-colloid coated coverslips. The area cleared of gold particles by migrating PAM after 24, 48, and 72 h was used as an indicator of cell mobility. The number of PAM recoverable by lavage was similar for both groups (2 x 10(5)), but the percentage of macrophages that made tracks was significantly smaller with 95% certainty in the O3 group. For sham-exposed and O3-exposed groups, the area cleared by PAM increased as the length of incubation increased, with the area cleared by the sham-exposed group being about 50% greater during each time period. When the two groups were compared statistically at each time point, the probability that they differed was, in each case, greater than 95%. It was concluded that the in vitro migrational potential of PAM was most likely decreased by in vivo exposure to O3.
- Published
- 1981
- Full Text
- View/download PDF
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