UCI Authors in PubMed
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Schriner SE,Lee K,Truong S,Salvadora KT,Maler S,Nam A,Lee T,Jafari M Department of Pharmaceutical Sciences, University of California Irvine, Irvine, California, United States of America. |
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Extension of Drosophila Lifespan by Rhodiola rosea through a Mechanism Independent from Dietary Restriction. PLoS One. 2013;8(5):e63886 Rhodiola rosea has been extensively used to improve physical and mental performance and to protect against stress. We, and others, have reported that R. rosea can extend lifespan in flies, worms, and yeast. However, its molecular mechanism is currently unknown. Here, we tested whether R. rosea might act through a pathway related to dietary restriction (DR) that can extend lifespan in a range of model organisms. While the mechanism of DR itself is also unknown, three molecular pathways have been associated with it: the silent information regulator 2 (SIR2) proteins, insulin and insulin-like growth factor signaling (IIS), and the target of rapamycin (TOR). In flies, DR is implemented through a reduction in dietary yeast content. We found that R. rosea extract extended lifespan in both sexes independent of the yeast content in the diet. We also found that the extract extended lifespan when the SIR2, IIS, or TOR pathways were genetically perturbed. Upon examination of water and fat content, we found that R. rosea decreased water content and elevated fat content in both sexes, but did not sensitize flies to desiccation or protect them against starvation. There were some sex-specific differences in response to R. rosea. In female flies, the expression levels of glycolytic genes and dSir2 were down-regulated, and NADH levels were decreased. In males however, R. rosea provided no protection against heat stress and had no effect on the major heat shock protein HSP70 and actually down-regulated the mitochondrial HSP22. Our findings largely rule out an elevated general resistance to stress and DR-related pathways as mechanistic candidates. The latter conclusion is especially relevant given the limited potential for DR to improve human health and lifespan, and presents R. rosea as a potential viable candidate to treat aging and age-related diseases in humans. PMID: 23704949 |
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Flombaum P,Gallegos JL,Gordillo RA,Rincón J,Zabala LL,Jiao N,Karl DM,Li WK,Lomas MW,Veneziano D,Vera CS,Vrugt JA,Martiny AC Departments of Earth System Science, Civil Engineering, and Ecology and Evolutionary Biology, University of California, Irvine, CA 92697. |
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Present and future global distributions of the marine Cyanobacteria Prochlorococcus and Synechococcus. Proc Natl Acad Sci U S A. 2013 May 23;: The Cyanobacteria Prochlorococcus and Synechococcus account for a substantial fraction of marine primary production. Here, we present quantitative niche models for these lineages that assess present and future global abundances and distributions. These niche models are the result of neural network, nonparametric, and parametric analyses, and they rely on >35,000 discrete observations from all major ocean regions. The models assess cell abundance based on temperature and photosynthetically active radiation, but the individual responses to these environmental variables differ for each lineage. The models estimate global biogeographic patterns and seasonal variability of cell abundance, with maxima in the warm oligotrophic gyres of the Indian and the western Pacific Oceans and minima at higher latitudes. The annual mean global abundances of Prochlorococcus and Synechococcus are 2.9 ± 0.1 × 10(27) and 7.0 ± 0.3 × 10(26) cells, respectively. Using projections of sea surface temperature as a result of increased concentration of greenhouse gases at the end of the 21st century, our niche models projected increases in cell numbers of 29% and 14% for Prochlorococcus and Synechococcus, respectively. The changes are geographically uneven but include an increase in area. Thus, our global niche models suggest that oceanic microbial communities will experience complex changes as a result of projected future climate conditions. Because of the high abundances and contributions to primary production of Prochlorococcus and Synechococcus, these changes may have large impacts on ocean ecosystems and biogeochemical cycles. PMID: 23703908 |
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Sakai AK,Weller SG,Campbell DR,Culley TM,Dunbar-Wallis AK,Andres AM Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697 USA. |
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Measure for measure: Comparing morphological and biomass traits for sex allocation in two gynodioecious species. Am J Bot. 2013 May 22;: • Premise of the study: Sex allocation models assume male and female traits are measured in a common currency, allocation traits show heritability, and tradeoffs between investment in the two sexual functions occur. The potential for model predictions and genetic parameters to depend on the currency used is not well understood, despite frequent use of measures not in a common currency.• Methods: We analyzed the relationship between common currency (biomass of carpels, seeds, and stamens) measures and morphological measures (numbers of ovules, seeds, and pollen) in Schiedea salicaria (12-13% females) and S. adamantis (39% females), two closely related gynodioecious species. Additionally, we compared heritabilities and genetic correlations for male and female allocation between these two types of measures.• Key results: Ovule, seed, and pollen number show greater sexual dimorphism in S. adamantis than in S. salicaria. Most but not all morphological traits and analogous biomass traits are highly correlated with a linear relationship. Narrow-sense heritabilities based on the two methods are often similar, but higher for ovule number than carpel mass and lower for anther number than stamen mass in S. adamantis. Neither trait type shows negative genetic correlations between male and female function.• Conclusions: Both trait types show greater sexual dimorphism in S. adamantis, and significant heritabilities suggest that morphological traits will continue to evolve with breeding system changes. Although most relationships between morphological and biomass traits are linear, curvilinear relationships for two traits suggest that caution is warranted if morphological and common currency traits are used interchangeably in fitness gain curves. PMID: 23703857 |
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Lee CS,Ho DV,Chan JY Department of Laboratory Medicine and Pathology, University of California Irvine, D440 Medical Sciences, Irvine, California, 92697, USA. |
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Nuclear factor-erythroid 2-related factor 1 regulates expression of proteasome genes in hepatocytes and protects against endoplasmic reticulum stress and steatosis in mice. FEBS J. 2013 May 22;: The ubiquitin proteasome system (UPS) is important in maintaining protein homeostasis. NFE2-related factor 1 (Nrf1), a transcription factor in the cap "n" collar (CNC) basic leucine zipper family, regulates expression of cytoprotective genes. It was previously shown that liver-specific knockout of Nrf1 (Nrf1LKO) leads to hepatic cell death, steatohepatitis and cancer. However, the mechanisms underlying these pathologies are not clear. Here, we report that Nrf1 is critical for proteasome gene expression in the liver. Liver-specific knockout of Nrf1 results in impaired basal and induced expression of proteasome genes, and diminished proteasome activity in hepatocytes. In addition, our findings demonstrated that ER stress signaling pathway was also activated in Nrf1LKO livers. Inhibition of proteasome activity leads to ER stress in Nrf1-deficient hepatocytes, prompting the development of steatosis in the liver. Our results indicate that Nrf1 plays an integral role in the maintenance of proteasome function in hepatocytes and in the prevention of liver steatosis development. Moreover, these results highlight an association between proteasome dysfunction, ER stress and steatosis. This article is protected by copyright. All rights reserved. PMID: 23702335 |
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Sohn W,Shreim S,Yoon R,Huynh VB,Dash A,Clayman R,Lee HJ University of California, Irvine, Urology, Orange, California, United States, Orange, California, United States ; wsohn@uci.edu. |
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EndockscopeTM: Using Mobile Technology to Create Global Point of Service Endoscopy. J Endourol. 2013 May 24;: Background and purpose: Recent advances and the widespread availability of smartphones have ushered in a new wave of innovations in healthcare. Herein, we present our initial experience with EndockscopeTM, a new docking system that optimizes the coupling of the iPhone 4S with modern endoscopes. Materials and Methods: Using the USAF resolution target, we compared the image resolution (line pairs/mm) of a flexible cystoscope coupled to the EndockscopeTM+iPhone to the Storz HD camera (H3-Z Versatile). We then utilized the Munsell ColorChecker chart, to compare the color resolution with a 0o laparoscope. Furthermore, 12 expert endoscopists blindly compared and evaluated images from a porcine model using a cystoscope and ureteroscope for both systems. Finally, we also compared the cost (average of two company listed prices) and weight (lbs) of the two systems. Results: Overall, the image resolution allowed by the EndockscopeTM was identical to the traditional HD camera (4.49 vs. 4.49 lp/mm). Red (∆E = 9.26 vs. 9.69) demonstrated better color resolution for iPhone, but green (∆E = 7.76 vs. 10.95), and blue (∆E = 12.35 vs. 14.66) revealed better color resolution with the Storz HD camera. Expert reviews of cystoscopic images acquired with the HD camera were superior in image, color and overall quality (p= 0.002, 0.042, and 0.003). In contrast, the ureteroscopic reviews yielded no statistical difference in image, color and overall (p=1, 0.203 and 0.120) quality. The overall cost of the EndockscopeTM+ iPhone was $154 compared to $46,623 for a standard HD system. The weight of the mobile-coupled system was 0.47 lbs and 1.01 lbs for the Storz HD camera. Conclusion: EndockscopeTM demonstrated feasibility of coupling endoscopes to a smartphone. The lighter and inexpensive EndockscopeTM acquired images of same resolution and acceptable color resolution. When evaluated by expert endoscopists, the quality of the images overall were equivalent for flexible ureteroscopy and somewhat inferior, but still acceptable for flexible cystoscopy. PMID: 23701228 |
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Liu Z,Antalek M,Nguyen L,Li X,Tian X,Le A,Zi X a Department of Urology , University of California , Irvine , Orange , California , USA. |
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The Effect of Gartanin, a Naturally Occurring Xanthone in Mangosteen Juice, on the mTOR Pathway, Autophagy, Apoptosis, and the Growth of Human Urinary Bladder Cancer Cell Lines. Nutr Cancer. 2013;65 Suppl 1:68-77 Garcinia mangostana, often referred to as mangosteen, is a fruit grown in Southeast Asia and has been used for centuries as a local beverage and natural medicine. Its bioactive compounds, xanthones (i.e., gartanin, α-mangostin, etc), have reported effects on ailments ranging from skin infections and inflammation to urinary tract infections. We demonstrate that mangosteen xanthones (i.e., gartanin and α-mangostin) at pharmacologically achievable concentrations inhibit the growth of cancer cell lines from different stages of human urinary bladder cancer. The growth inhibitory effects of gartanin in mouse embryonic fibroblasts are at least in part dependent on the existence of p53 or TSC1. Indeed, further studies have shown that gartanin treatment of bladder cancer cell lines T24 and RT4 resulted in a marked suppression of p70S6 and 4E-BP1 expression and induction of autophagy, suggesting the inhibition of the mTOR pathway. In addition, gartanin downregulated the expression of Bcl-2 and activated the p53 pathway leading to apoptosis induction. Together, these results suggested that gartanin is a multiple targeting agent that is suitable for further study into its chemopreventive properties for human urinary bladder cancer. PMID: 23682785 |
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Murphy CR,Quan V,Kim D,Peterson E,Whealon M,Tan G,Evans K,Meyers H,Cheung M,Lee BY,Mukamel DB,Huang SS Division of Infectious Diseases and Health Policy Research Institute, University of California-Irvine School of Medicine, Irvine, CA, USA. courtner@uci.edu |
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Nursing home characteristics associated with methicillin-resistant Staphylococcus aureus (MRSA) Burden and Transmission. BMC Infect Dis. 2012;12:269 MRSA prevalence in nursing homes often exceeds that in hospitals, but reasons for this are not well understood. We sought to measure MRSA burden in a large number of nursing homes and identify facility characteristics associated with high MRSA burden. PMID: 23095678 |
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Allen-Sharpley MR,Cramer KS Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA. |
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Coordinated Eph-ephrin signaling guides migration and axon targeting in the avian auditory system. Neural Dev. 2012;7:29 In the avian sound localization circuit, nucleus magnocellularis (NM) projects bilaterally to nucleus laminaris (NL), with ipsilateral and contralateral NM axon branches directed to dorsal and ventral NL dendrites, respectively. We previously showed that the Eph receptor EphB2 is expressed in NL neuropil and NM axons during development. Here we tested whether EphB2 contributes to NM-NL circuit formation. PMID: 22908944 |
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Ravel VA,Molnar MZ,Streja E,Kim JC,Victoroff A,Jing J,Benner D,Norris KC,Kovesdy CP,Kopple JD,Kalantar-Zadeh K Harold Simmons Center for Chronic Disease Research & Epidemiology, University of California Irvine Medical Center, Irvine, CA. |
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Low Protein Nitrogen Appearance as a Surrogate of Low Dietary Protein Intake Is Associated with All-Cause Mortality in Maintenance Hemodialysis Patients. J Nutr. 2013 May 22;: To determine the association between all-cause mortality and dietary protein intake in patients with chronic kidney disease, we performed a large-scale, 8-y prospective cohort study in 98,489 maintenance hemodialysis patients from a multicenter dialysis care provider. Compared with the reference level (60 to PMID: 23700345 |
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Fu H,Cooray A,Feruglio C,Ivison RJ,Riechers DA,Gurwell M,Bussmann RS,Harris AI,Altieri B,Aussel H,Baker AJ,Bock J,Boylan-Kolchin M,Bridge C,Calanog JA,Casey CM,Cava A,Chapman SC,Clements DL,Conley A,Cox P,Farrah D,Frayer D,Hopwood R,Jia J,Magdis G,Marsden G,Martínez-Navajas P,Negrello M,Neri R,Oliver SJ,Omont A,Page MJ,Pérez-Fournon I,Schulz B,Scott D,Smith A,Vaccari M,Valtchanov I,Vieira JD,Viero M,Wang L,Wardlow JL,Zemcov M Department of Physics and Astronomy, University of California, Irvine, California 92697, USA. |
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The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3. Nature. 2013 May 22;: Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5 × 10(10) solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies that already have stellar masses above 2 × 10(11) solar masses at z ≈ 2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at z = 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19 kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4 × 10(11) solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by z ≈ 1.5. PMID: 23698363 |
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Macdonald MR,Bates JE,Ziller JW,Furche F,Evans WJ Department of Chemistry, University of California , Irvine, California 92697-2025, United States. |
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Completing the Series of +2 Ions for the Lanthanide Elements: Synthesis of Molecular Complexes of Pr(2+), Gd(2+), Tb(2+), and Lu(2+) J Am Chem Soc. 2013 May 22;: The first examples of crystallographically characterizable complexes of Tb(2+), Pr(2+), Gd(2+), and Lu(2+) have been isolated, which demonstrate that Ln(2+) ions are accessible in soluble molecules for all of the lanthanides except radioactive promethium. The first molecular Tb(2+) complexes have been obtained from the reaction of Cp'3Ln (Cp' = C5H4SiMe3, Ln = rare earth) with potassium in the presence of 18-crown-6 in Et2O at -35 °C under argon: [(18-crown-6)K][Cp'3Tb], {[(18-crown-6)K][Cp'3Tb]}n, and {[K(18-crown-6)]2(μ-Cp')}{Cp'3Tb}. The first complex is analogous to previously isolated Y(2+), Ho(2+), and Er(2+) complexes, the second complex shows an isomeric structural form of these Ln(2+) complexes, and the third complex shows that [(18-crown-6)K](1+) alone is not the only cation that will stabilize these reactive Ln(2+) species, a result that led to further exploration of cation variants. With 2.2.2-cryptand in place of 18-crown-6 in the Cp'3Ln/K reaction, a more stable complex of Tb(2+) was produced as well as more stable Y(2+), Ho(2+), and Er(2+) analogs: [K(2.2.2-cryptand)][Cp'3Ln]. Exploration of this 2.2.2-cryptand-based reaction with the remaining lanthanides for which Ln(2+) had not been observed in molecular species provided crystalline Pr(2+), Gd(2+), and Lu(2+) complexes. These Ln(2+) complexes, [K(2.2.2-cryptand)][Cp'3Ln] (Ln = Y, Pr, Gd, Tb, Ho, Er, Lu), all have similar UV-vis spectra and exhibit Ln-C(Cp') bond distances that are ∼0.03 Å longer than those in the Ln(3+) precursors, Cp'3Ln. These data, as well as density functional theory calculations and EPR spectra, suggest that a 4f(n)5d(1) description of the electron configuration in these Ln(2+) ions is more appropriate than 4f(n+1). PMID: 23697603 |
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Lee B,Dai X Department of Biological Chemistry, School of Medicine, University of California, D250 Med Sci I, Irvine, 92697-1700, CA, USA. |
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Transcriptional control of epidermal stem cells. Adv Exp Med Biol. 2013;786:157-73 Transcriptional regulation is fundamentally important for the progression of tissue stem cells through different stages of development and differentiation. Mammalian skin epidermis is an excellent model system to study such regulatory mechanisms due to its easy accessibility, stereotypic spatial arrangement, and availability of well-established cell type/lineage differentiation markers. Moreover, epidermis is one of the few mammalian tissues the stem cells of which can be maintained and propagated in culture to generate mature cell types and a functional tissue (reviewed in [1]), offering in vitro and ex vivo platforms to probe deep into the underlying cell and molecular mechanisms of biological functions. PMID: 23696356 |
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Wong BG,Paz A,Corrado MA,Ramos BR,Cinquin A,Cinquin O,Hui EE Department of Biomedical Engineering, University of California, Irvine, CA 92697-2715, USA. eehui@uci.edu. |
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Live imaging reveals active infiltration of mitotic zone by its stem cell niche. Integr Biol (Camb). 2013 May 22;: Stem cells niches are increasingly recognized as dynamic environments that play a key role in transducing signals that allow an organism to exert control on its stem cells. Live imaging of stem cell niches in their in vivo setting is thus of high interest to dissect stem cell controls. Here we report a new microfluidic design that is highly amenable to dissemination in biology laboratories that have no microfluidics expertise. This design has allowed us to perform the first time lapse imaging of the C. elegans germline stem cell niche. Our results show that this niche is strikingly dynamic, and that morphological changes that take place during development are the result of a highly active process. These results lay the foundation for future studies to dissect molecular mechanisms by which stem cell niche morphology is modulated, and by which niche morphology controls stem cell behavior. PMID: 23695198 |
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Pedram A,Razandi M,O'Mahony F,Harvey H,Harvey BJ,Levin ER 1Department of Medicine, University of California, Irvine, Irvine, CA 92717, USA. |
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Estrogen reduces lipid content in the liver exclusively from membrane receptor signaling. Sci Signal. 2013;6(276):ra36 Estrogen induces signal transduction through estrogen receptor α (ERα), which localizes to both the plasma membrane and nucleus. Using wild-type mice, ERα knockout (ERKO) mice, or transgenic mice expressing only the ligand-binding domain of ERα exclusively at the plasma membrane (MOER), we compared the transcriptional profiles of liver tissue extracts after mice were injected with the ERα agonist propyl-pyrazole-triol (PPT). The expression of many lipid synthesis-related genes was comparably decreased in livers from MOER or wild-type mice but was not suppressed in ERKO mice, indicating that only membrane-localized ERα was necessary for their suppression. Cholesterol, triglyceride, and fatty acid content was decreased only in livers from wild-type and MOER mice exposed to PPT, but not in the livers from the ERKO mice, validating the membrane-driven signaling pathway on a physiological level. PPT-triggered activation of ERα at the membrane induced adenosine monophosphate-activated protein kinase to phosphorylate sterol regulatory element-binding factor 1 (Srebf1), preventing its association with and therefore its proteolytic cleavage by site-1 protease. Consequently, Srebf1 was sequestered in the cytoplasm, preventing the expression of cholesterol synthesis-associated genes. Thus, we showed that inhibition of gene expression mediated by membrane-localized ERα caused a metabolic phenotype that did not require nuclear ERα. PMID: 23695162 |
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Quigley RJ,Robicheaux GW,Lee TQ Orthopaedic Biomechanics Laboratory, VA Long Beach Healthcare System, CA, and University of California, Irvine, USA. |
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The proximal and distal position of the radius relative to the ulna through a full range of elbow flexion and forearm rotation. J Hand Surg Eur Vol. 2013 May 21;: The purpose of this study was to measure the position of the radius relative to the ulna through a complete range of elbow flexion and forearm rotation. Twenty cadaveric upper extremities were mounted on a testing jig that allowed simultaneous control of elbow flexion and forearm rotation. The longitudinal position of the radius relative to the ulna was measured using a three-dimensional digitizer at full pronation, mid-pronation (45°), neutral (0°), mid-supination (45°) and full supination at 10°, 30°, 60°, 90° and 120° of elbow flexion. Our results showed that the radius is located distally when in supination and is located more proximally as it is rotated into pronation. The longitudinal position of the radius changes over 9 mm when moving through a complete arc of forearm rotation. The angle of elbow flexion had a secondary effect on the longitudinal position of the radius, causing changes of less than 0.8 mm. PMID: 23695153 |
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Cannesson M,Le Manach Y *School of Medicine, University of California, Irvine, California. mcanness@uci.edu. |
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In reply. Anesthesiology. 2013 Jun;118(6):1481 PMID: 23695094 |
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Potkin S,Bugarski-Kirola D,Edgar C,Le Scouiller S,Kunovac J,Velasco EM,Berardo C,Garibaldi GM University of California-Irvine, Irvine, CA, USA. |
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Development of the readiness for work questionnaire in schizophrenia. Value Health. 2013 May;16(3):A32 PMID: 23694296 |
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Boicey C University of California, Irvine, Orange, California, USA. |
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Innovations in social media: the MappyHealth experience. Nurs Manage. 2013 Mar;44(3):10-1 PMID: 23435102 |
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Kimball S,Angert AL,Huxman TE,Venable DL Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA. skimball@uci.edu |
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Differences in the timing of germination and reproduction relate to growth physiology and population dynamics of Sonoran Desert winter annuals. Am J Bot. 2011 Nov;98(11):1773-81 Trait differences can promote distinct survival and fecundity responses to environmental fluctuations. In a Sonoran Desert winter annual plant community, we have identified a tradeoff between relative growth rate (RGR) and water-use efficiency (WUE) that predicts interannual variation in reproductive success. Here we test the hypothesis that traits underlying RGR and WUE differences are linked to seasonal phenology. PMID: 22003177 |
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Skarecky DW Department of Urology, University of California, Irvine, CA 92697, USA. |
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Robotic-Assisted Radical Prostatectomy after the First Decade: Surgical Evolution or New Paradigm. ISRN Urol. 2013;2013:157379 Early studies indicate that robotic-assisted radical prostatectomy (RARP) has promising short-term outcomes; however, RARP is beyond its infancy, and the long-term report cards are now beginning. The important paradigm shift introduced by RARP is the reevaluation of the entire open radical prostatectomy experience in surgical technique by minimizing blood loss and complications, maximizing cancer free outcomes, and a renewed assault in preserving quality of life outcomes by many novel mechanisms. RARP provides a new technical "canvas" for surgical masters to create upon, and in ten years, has reinvigorated a 100-year-old "gold standard" surgery. PMID: 23691367 |
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Qi X,Vargas E,Larsen L,Knapp W,Hatfield GW,Lathrop R,Sandmeyer S Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America. |
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Directed DNA Shuffling of Retrovirus and Retrotransposon Integrase Protein Domains. PLoS One. 2013;8(5):e63957 Chimeric proteins are used to study protein domain functions and to recombine protein domains for novel or optimal functions. We used a library of chimeric integrase proteins to study DNA integration specificity. The library was constructed using a directed shuffling method that we adapted from fusion PCR. This method easily and accurately shuffles multiple DNA gene sequences simultaneously at specific base-pair positions, such as protein domain boundaries. It produced all 27 properly-ordered combinations of the amino-terminal, catalytic core, and carboxyl-terminal domains of the integrase gene from human immunodeficiency virus, prototype foamy virus, and Saccharomyces cerevisiae retrotransposon Ty3. Retrotransposons can display dramatic position-specific integration specificity compared to retroviruses. The yeast retrotransposon Ty3 integrase interacts with RNA polymerase III transcription factors to target integration at the transcription initiation site. In vitro assays of the native and chimeric proteins showed that human immunodeficiency virus integrase was active with heterologous substrates, whereas prototype foamy virus and Ty3 integrases were not. This observation was consistent with a lower substrate specificity for human immunodeficiency virus integrase than for other retrovirus integrases. All eight chimeras containing the Ty3 integrase carboxyl-terminal domain, a candidate targeting domain, failed to target strand transfer in the presence of the targeting protein, suggesting that multiple domains of the Ty3 integrase cooperate in this function. PMID: 23691126 |
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Vaziri ND,Yuan J,Khazaeli M,Masuda Y,Ichii H,Liu S Division of Nephrology and Hypertension, University of California, Irvine, Calif., USA. |
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Oral Activated Charcoal Adsorbent (AST-120) Ameliorates Chronic Kidney Disease-Induced Intestinal Epithelial Barrier Disruption. Am J Nephrol. 2013 May 15;37(6):518-525 Background: Chronic kidney disease (CKD) impairs intestinal barrier function which by allowing influx of noxious products causes systemic inflammation. We have recently shown that intestinal barrier dysfunction in CKD is due to degradation of epithelial tight junction (TJ) which is, in part, mediated by influx of urea and its conversion to ammonia by microbial urease. We hypothesized that by adsorbing urea and urea-derived ammonia, oral activated charcoal (AST-120) may ameliorate CKD-induced intestinal epithelial barrier disruption and systemic inflammation. Methods: Rats were randomized to the CKD or control groups. The CKD group was fed a chow containing 0.7% adenine for 2 weeks. They were then randomized to receive a chow with or without AST-120 (4 g/kg/day) for 2 weeks. Rats consuming regular diet served as controls. Animals were then euthanized, colons were removed and processed for Western blot and immunohistology, and plasma was used to measure endotoxin and oxidative and inflammatory markers. Results: Compared with the controls, the untreated CKD rats showed elevated plasma endotoxin, IL-6, TNF-α, MCP-1, CINC-3, L-selectin, ICAM-1, and malondialdehyde, and depletions of colonic epithelial TJ proteins, claudin-1, occludin, and ZO1. Administration of AST-120 resulted in partial restoration of the epithelial TJ proteins and reduction in plasma endotoxin and markers of oxidative stress and inflammation. Conclusions : CKD animals exhibited depletion of the key protein constituents of the colonic epithelial TJ which was associated with systemic inflammation, oxidative stress and endotoxemia. Administration of AST-120 attenuated uremia-induced disruption of colonic epithelial TJ and the associated endotoxemia, oxidative stress and inflammation. PMID: 23689670 |
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Phillips LF Chemistry Department, University of California at Irvine, USA. |
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Atmospheric reactions on electrically charged surfaces. Phys Chem Chem Phys. 2013 May 20;: It is proposed that tropospheric NO2 at concentrations in the parts-per-billion range can be efficiently converted to HONO in a dust storm, by a process that is initiated by electron capture by NO2 from a negatively-charged dust particle. The electron capture is visualized as a harpoon-type process that does not require the NO2 to be adsorbed on the particle. The resulting electronically excited [NO2(-)]* ion reacts with water to form an HONO molecule plus an OH(-)·(H2O)n cluster ion. It is suggested that analogous processes can occur on other atmospheric aerosol particles with both positive and negative charges, with other molecules of high electron affinity such as SO2, and also, because the earth's surface is effectively the negative plate of a planet-sized capacitor, at the surfaces of terrestrial solids, lakes and oceans. PMID: 23689618 |
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Allison SD,Lu Y,Weihe C,Goulden ML,Martiny AC,Treseder KK,Martiny JB Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697, USA. allisons@uci.edu |
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Microbial abundance and composition influence litter decomposition response to environmental change. Ecology. 2013 Mar;94(3):714-25 Rates of ecosystem processes such as decomposition are likely to change as a result of human impacts on the environment. In southern California, climate change and nitrogen (N) deposition in particular may alter biological communities and ecosystem processes. These drivers may affect decomposition directly, through changes in abiotic conditions, and indirectly through changes in plant and decomposer communities. To assess indirect effects on litter decomposition, we reciprocally transplanted microbial communities and plant litter among control and treatment plots (either drought or N addition) in a grassland ecosystem. We hypothesized that drought would reduce decomposition rates through moisture limitation of decomposers and reductions in plant litter quality before and during decomposition. In contrast, we predicted that N deposition would stimulate decomposition by relieving N limitation of decomposers and improving plant litter quality. We also hypothesized that adaptive mechanisms would allow microbes to decompose litter more effectively in their native plot and litter environments. Consistent with our first hypothesis, we found that drought treatment reduced litter mass loss from 20.9% to 15.3% after six months. There was a similar decline in mass loss of litter inoculated with microbes transplanted from the drought treatment, suggesting a legacy effect of drought driven by declines in microbial abundance and possible changes in microbial community composition. Bacterial cell densities were up to 86% lower in drought plots and at least 50% lower on litter derived from the drought treatment, whereas fungal hyphal lengths increased by 13-14% in the drought treatment. Nitrogen effects on decomposition rates and microbial abundances were weaker than drought effects, although N addition significantly altered initial plant litter chemistry and litter chemistry during decomposition. However, we did find support for microbial adaptation to N addition with N-derived microbes facilitating greater mass loss in N plots than in control plots. Our results show that environmental changes can affect rates of ecosystem processes directly through abiotic changes and indirectly through microbial abundances and communities. Therefore models of ecosystem response to global change may need to represent microbial biomass and community composition to make accurate predictions. PMID: 23687897 |
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Samarasena JB,Nguyen NT,Lee JG Division of Gastroenterology, University of California-Irvine, Orange, California. |
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Endoscopic retrograde cholangiopancreatography in patients with roux-en-Y anatomy. J Interv Gastroenterol. 2012 4;2(2):78-83 PMID: 23687591 |
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