79 results on '"Stein, David A."'
Search Results
2. Quadrature by fundamental solutions: kernel-independent layer potential evaluation for large collections of simple objects.
- Author
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Stein, David B. and Barnett, Alex H.
- Abstract
Well-conditioned boundary integral methods for the solution of elliptic boundary value problems (BVPs) are powerful tools for static and dynamic physical simulations. When there are many close-to-touching boundaries (e.g., in complex fluids) or when the solution is needed in the bulk, nearly singular integrals must be evaluated at many targets. We show that precomputing a linear map from surface density to an effective source representation renders this task highly efficient, in the common case where each object is “simple”, i.e., its smooth boundary needs only moderately many nodes. We present a kernel-independent method needing only an upsampled smooth surface quadrature, and one dense factorization, for each distinct shape. No (near-)singular quadrature rules are needed. The resulting effective sources are drop-in compatible with fast algorithms, with no local corrections nor bookkeeping. Our extensive numerical tests include 2D FMM-based Helmholtz and Stokes BVPs with up to 1000 objects (281000 unknowns), and a 3D Laplace BVP with 10 ellipsoids separated by 1/30 of a diameter. We include a rigorous analysis for analytic data in 2D and 3D. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Structural signatures: a web server for exploring a database of and generating protein structural features from human cell lines and tissues.
- Author
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Zatorski, Nicole, Stein, David, Rahman, Rayees, Iyengar, Ravi, and Schlessinger, Avner
- Subjects
- *
INTERNET servers , *CYTOSKELETAL proteins , *CELL lines , *TISSUES , *DATABASES , *LUNG cancer - Abstract
Structural features of proteins provide powerful insights into biological function and similarity. Specifically, previous work has demonstrated that structural features of tissue and drug-treated cell line samples can be used to predict tissue type and characterize drug relationships, respectively. We have developed structural signatures, a web server for annotating and analyzing protein features from gene sets that are often found in transcriptomic and proteomic data. This platform provides access to a structural feature database derived from normal and disease human tissue samples. We show how analysis using this database can shed light on the relationship between states of single-cell RNA-sequencing lung cancer samples. These various structural feature signatures can be visualized on the server itself or downloaded for additional analysis. The structural signatures server tool is freely available at https://structural-server.kinametrix.com/. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Identification of discriminative gene-level and protein-level features associated with pathogenic gain-of-function and loss-of-function variants.
- Author
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Sevim Bayrak, Cigdem, Stein, David, Jain, Aayushee, Chaudhary, Kumardeep, Nadkarni, Girish N., Van Vleck, Tielman T., Puel, Anne, Boisson-Dupuis, Stephanie, Okada, Satoshi, Stenson, Peter D., Cooper, David N., Schlessinger, Avner, and Itan, Yuval
- Subjects
- *
GENETIC variation , *GENETIC mutation , *PHENOTYPES , *HEREDITY , *PROTEIN binding , *NATURAL language processing , *FEATURE selection - Abstract
Identifying whether a given genetic mutation results in a gene product with increased (gain-of-function; GOF) or diminished (loss-of-function; LOF) activity is an important step toward understanding disease mechanisms because they may result in markedly different clinical phenotypes. Here, we generated an extensive database of documented germline GOF and LOF pathogenic variants by employing natural language processing (NLP) on the available abstracts in the Human Gene Mutation Database. We then investigated various gene- and protein-level features of GOF and LOF variants and applied machine learning and statistical analyses to identify discriminative features. We found that GOF variants were enriched in essential genes, for autosomal-dominant inheritance, and in protein binding and interaction domains, whereas LOF variants were enriched in singleton genes, for protein-truncating variants, and in protein core regions. We developed a user-friendly web-based interface that enables the extraction of selected subsets from the GOF/LOF database by a broad set of annotated features and downloading of up-to-date versions. These results improve our understanding of how variants affect gene/protein function and may ultimately guide future treatment options. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Beyond the Carceral Imagination.
- Author
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Stein, David
- Subjects
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REFUGEE camps , *CRIMINAL justice personnel , *SOCIAL conflict , *LEGAL history , *POLITICAL persecution , *HOMICIDE rates - Published
- 2020
6. Ultrasound Imaging for Risk Assessment in Atherosclerosis.
- Author
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Stein, David C. and Kaufmann, Beat A.
- Subjects
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ATHEROSCLEROSIS , *DIAGNOSTIC ultrasonic imaging , *NEOVASCULARIZATION , *ATHEROSCLEROTIC plaque , *BIOMECHANICS , *BLOOD vessels , *PROGNOSIS - Abstract
Atherosclerosis and its consequences like acute myocardial infarction or stroke are highly prevalent in western countries, and the incidence of atherosclerosis is rapidly rising in developing countries. Atherosclerosis is a disease that progresses silently over several decades before it results in the aforementioned clinical consequences. Therefore, there is a clinical need for imaging methods to detect the early stages of atherosclerosis and to better risk stratify patients. In this review, we will discuss how ultrasound imaging can contribute to the detection and risk stratification of atherosclerosis by (a) detecting advanced and early plaques; (b) evaluating the biomechanical consequences of atherosclerosis in the vessel wall; (c) assessing plaque neovascularization and (d) imaging the expression of disease-relevant molecules using molecular imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
7. Inhibition of Dengue Virus Replication by a Class of Small-Molecule Compounds That Antagonize Dopamine Receptor D4 and Downstream Mitogen-Activated Protein Kinase Signaling.
- Author
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Smith, Jessica L., Stein, David A., Shum, David, Fischer, Matthew A., Radu, Constantin, Bhinder, Bhavneet, Djaballah, Hakim, Nelson, Jay A., Früh, Klaus, and Hirsch, Alec J.
- Subjects
- *
DENGUE viruses , *SMALL molecules , *DOPAMINE receptors , *MITOGEN-activated protein kinases , *WEST Nile virus , *SINDBIS virus , *EPIDERMAL growth factor receptors - Abstract
Dengue viruses (DENV) are endemic pathogens of tropical and subtropical regions that cause significant morbidity and mortality worldwide. To date, no vaccines or antiviral therapeutics have been approved for combating DENV-associated disease. In this paper, we describe a class of tricyclic small-molecule compounds-dihydrodibenzothiepines (DHBTs), identified through highthroughput screening-with potent inhibitory activity against DENV serotype 2. SKI-417616, a highly active representative of this class, displayed activity against all four serotypes of DENV, as well as against a related flavivirus, West Nile virus (WNV), and an alphavirus, Sindbis virus (SINV). This compound was characterized to determine its mechanism of antiviral activity. Investigation of the stage of the viral life cycle affected revealed that an early event in the life cycle is inhibited. Due to the structural similarity of the DHBTs to known antagonists of the dopamine and serotonin receptors, we explored the roles of two of these receptors, serotonin receptor 2A (5HTR2A) and the D4 dopamine receptor (DRD4), in DENV infection. Antagonism of DRD4 and subsequent downstream phosphorylation of epidermal growth factor receptor (EGFR)-related kinase (ERK) were found to impact DENV infection negatively, and blockade of signaling through this network was confirmed as the mechanism of anti- DENV activity for this class of compounds. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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8. Localized serine protease activity and the establishment of Drosophila embryonic dorsoventral polarity.
- Author
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Stein, David, Yong Suk Cho, and Stevens, Leslie M.
- Published
- 2013
- Full Text
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9. Antiviral effects of autologous CD4 T cells genetically modified with a conditionally replicating lentiviral vector expressing long antisense to HIV.
- Author
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Tebas, Pablo, Stein, David, Binder-Scholl, Gwendolyn, Mukherjee, Rithun, Brady, Troy, Rebello, Tessio, Humeau, Laurent, Kalos, Michael, Papasawas, Emmanouil, Montaner, Luis J., Schullery, Daniel, Shaheen, Farida, Brennan, Andrea L., Zhaohui Zheng, Cotte, Julio, Slepushkin, Vladimir, Veloso, Elizabeth, Mackley, Adonna, Wei-Ting Hwang, and Aberra, Faten
- Subjects
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T cells , *VIREMIA , *BLOODBORNE infections , *SEPSIS , *VIRUS diseases - Abstract
We report the safety and tolerability of 87 infusions of lentiviral vector-modified autologous CD4 T cells (VRX496-T; trade name, Lexgenleucel-T) in 17 HIV patients with well-controlled viremia. Antiviral effects were studied during analytic treatment interruption in a subset of 13 patients. VRX496-T was associated with a decrease in viral load set points in 6 of 8 subjects (P = .08). In addition, A→ G transitions were enriched in HIV sequences after infusion, which is consistent with a model in which transduced CD4 T cells exert antisense-mediated genetic pressure on HIV during infection. Engraftment of vector-modified CD4 T cells was measured in gut-associated lymphoid tissue and was correlated with engraftment in blood. The engraftment half-life in the blood was approximately 5 weeks, with stable persistence in some patients for up to 5 years. Conditional replication of VRX496 was detected periodically through 1 year after infusion. No evidence of clonal selection of lentiviral vector-transduced T cells or integration enrichment near oncogenes was detected. This is the first demonstration that gene-modified cells can exert genetic pressure on HIV. We conclude that gene-modified T cells have the potential to decrease the fitness of HIV-1 and conditionally replicative lentiviral vectors have a promising safety profile in T cells. This study is registered at www.clinicaltrials.gov as number NCT00295477. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
10. From ‘hello’ to higher-order thinking: The effect of coaching and feedback on online chats
- Author
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Stein, David S., Wanstreet, Constance E., Slagle, Paula, Trinko, Lynn A., and Lutz, Michelle
- Subjects
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ONLINE chat , *CRITICAL thinking , *TEACHING , *PSYCHOLOGICAL feedback , *CURRICULUM , *TEACHING aids , *COMPUTER network resources - Abstract
Abstract: This exploratory study examined the effect of a coaching and feedback intervention in teaching presence and social presence on higher-order thinking in an online community of inquiry. Coaching occurred before each chat, and feedback was provided immediately afterwards. The findings suggest that over time, the frequency of higher-order thinking will increase more in a group that receives coaching and feedback than in a group that does not receive coaching and feedback. In addition, the findings suggest that the Community of Inquiry framework has benefits beyond its use in course design, facilitation, and assessment to include serving as a guide to coaching. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
11. Inhibition of Influenza Virus Infection in Human Airway Cell Cultures by an Antisense Peptide-Conjugated Morpholino Oligomer Targeting the Hemagglutinin-Activating Protease TMPRSS2.
- Author
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Böttcher-Friebertshäuser, Eva, Stein, David A., Klenk, Hans-Dieter, and Garten, Wolfgang
- Subjects
- *
INFLUENZA , *VIRUS diseases , *CELL culture , *EPITHELIAL cells , *OLIGOMERS , *INFLUENZA A virus , *VIROLOGY - Abstract
Influenza A viruses constitute a major and ongoing global public health concern. Current antiviral strategies target viral gene products; however, the emergence of drug-resistant viruses highlights the need for novel antiviral approaches. Cleavage of the influenza virus hemagglutinin (HA) by host cell proteases is crucial for viral infectivity and therefore presents a potential drug target. Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMO) are single-stranded-DNA-like antisense agents that readily enter cells and can act as antisense agents by sterically blocking cRNA. Here, we evaluated the effect of PPMO targeted to regions of the pre-mRNA or mRNA of the HA-cleaving protease TMPRSS2 on proteolytic activation and spread of influenza viruses in human Calu-3 airway epithelial cells. We found that treatment of cells with a PPMO (T-ex5) designed to interfere with TMPRSS2 pre-mRNA splicing resulted in TMPRSS2 mRNA lacking exon 5 and consequently the expression of a truncated and enzymatically inactive form of TMPRSS2. Altered splicing of TMPRSS2 mRNA by the T-ex5 PPMO prevented HA cleavage in different human seasonal and pandemic influenza A viruses and suppressed viral titers by 2 to 3 log10 units, strongly suggesting that TMPRSS2 is responsible for HA cleavage in Calu-3 airway cells. The data indicate that PPMO provide a useful reagent for investigating HA-activating proteases and may represent a promising strategy for the development of novel therapeutics to address influenza infections. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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12. Localization and Activation of the Drosophila Protease Easter Require the ER-Resident Saposin-like Protein Seele
- Author
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Stein, David, Charatsi, Iphigenie, Cho, Yong Suk, Zhang, Zhenyu, Nguyen, Jesse, DeLotto, Robert, Luschnig, Stefan, and Moussian, Bernard
- Subjects
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PROTEOLYTIC enzymes , *ENZYME activation , *GASTRULATION , *SERINE proteinases , *GENETIC mutation , *DROSOPHILA - Abstract
Summary: Drosophila embryonic dorsal-ventral polarity is generated by a series of serine protease processing events in the egg perivitelline space. Gastrulation Defective processes Snake, which then cleaves Easter, which then processes Spätzle into the activating ligand for the Toll receptor []. seele was identified in a screen for mutations that, when homozygous in ovarian germline clones, lead to the formation of progeny embryos with altered embryonic patterning; maternal loss of seele function leads to the production of moderately dorsalized embryos []. By combining constitutively active versions of Gastrulation Defective, Snake, Easter, and Spätzle with loss-of-function alleles of seele, we find that Seele activity is dispensable for Spätzle-mediated activation of Toll but is required for Easter, Snake, and Gastrulation Defective to exert their effects on dorsal-ventral patterning. Moreover, Seele function is required specifically for secretion of Easter from the developing embryo into the perivitelline space and for Easter processing. Seele protein resides in the endoplasmic reticulum of blastoderm embryos, suggesting a role in the trafficking of Easter to the perivitelline space, prerequisite to its processing and function. Easter transport to the perivitelline space represents a previously unappreciated control point in the signal transduction pathway that controls Drosophila embryonic dorsal-ventral polarity. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
13. Anatole Petrovich Andriashev (1910-2009).
- Author
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Stein, David L. and Chernova, Natalia V.
- Subjects
- ANDRIASHEV, Anatole Petrovich
- Abstract
The article presents an obituary for Russian ichthyologist Anatole Petrovich Andriashev.
- Published
- 2009
- Full Text
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14. Severe Acute Respiratory Syndrome Coronavirus Triggers Apoptosis via Protein Kinase R but Is Resistant to Its Antiviral Activity.
- Author
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Krähling, Verena, Stein, David A., Spiegel, Martin, Weber, Friedemann, and Mühlberger, Elke
- Subjects
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APOPTOSIS , *ADULT respiratory distress syndrome , *CORONAVIRUSES , *PHOSPHORYLATION , *INTERFERONS - Abstract
In this study, infection of 293/ACE2 cells with severe acute respiratory syndrome coronavirus (SARS-CoV) activated several apoptosis-associated events, namely, cleavage of caspase-3, caspase-8, and poly(ADP-ribose) polymerase 1 (PARP), and chromatin condensation and the phosphorylation and hence inactivation of the eukaryotic translation initiation factor 2α (eIF2α). In addition, two of the three cellular eIF2α kinases known to be virus induced, protein kinase R (PKR) and PKR-like endoplasmic reticulum kinase (PERK), were activated by SARS-CoV. The third kinase, general control nonderepressible-2 kinase (GCN2), was not activated, but late in infection the level of GCN2 protein was significantly reduced. Reverse transcription-PCR analyses revealed that the reduction of GCN2 protein was not due to decreased transcription or stability of GCN2 mRNA. The specific reduction of PKR protein expression by antisense peptide-conjugated phosphorodiamidate morpholino oligomers strongly reduced cleavage of PARP in infected cells. Surprisingly, the knockdown of PKR neither enhanced SARS-CoV replication nor abrogated SARS-CoV-induced eIF2α phosphorylation. Pretreatment of cells with beta interferon prior to SARS-CoV infection led to a significant decrease in PERK activation, eIF2α phosphorylation, and SARS-CoV replication. The various effects of beta interferon treatment were found to function independently on the expression of PKR. Our results show that SARS-CoV infection activates PKR and PERK, leading to sustained eIF2α phosphorylation. However, virus replication was not impaired by these events, suggesting that SARS-CoV possesses a mechanism to overcome the inhibitory effects of phosphorylated eIF2α on viral mRNA translation. Furthermore, our data suggest that viral activation of PKR can lead to apoptosis via a pathway that is independent of eIF2α phosphorylation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
15. Inhibition of Respiratory Syncytial Virus Infections With Morpholino Oligomers in Cell Cultures and in Mice.
- Author
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Shen-Hao Lai, Stein, David A., Guerrero-Plata, Antonieta, Sui-Ling Liao, Ivanciuc, Teodora, Chao Hong, Iversen, Patrick L., Casola, Antonella, and Garofalo, Roberto P.
- Subjects
- *
RESPIRATORY syncytial virus , *PARAMYXOVIRUSES , *VIRUS diseases , *OLIGOMERS , *POLYMERS , *CELL culture , *MOUSE diseases - Abstract
Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in infants, young children, and high-risk adults. Currently, there is no vaccine to prevent RSV infection, and the available therapeutic agents are of limited utility. Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) are a class of antisense agents that can enter cells readily and interfere with viral protein expression through steric blocking of complementary RNA. Two antisense PPMOs, designed to target sequence that includes the 5′-terminal region and translation start-site region of RSV L mRNA, were tested for anti-RSV activity in cultures of two human-airway cell lines. Both PPMOs showed minimal cytotoxicity and one of them, (AUG-2), reduced viral titers by >2.0 log10. Intranasal (i.n.) treatment of BALB/c mice with AUG-2 PPMO before the RSV inoculation produced a reduction in viral titer of 1.2 log10 in lung tissue at day 5 postinfection (p.i.), and attenuated pulmonary inflammation at day 7 postinfection. These data show that the AUG-2 PPMO possesses potent anti-RSV activity and is worthy of further investigation as a candidate for potential therapeutic application.Molecular Therapy (2008) 16 6, 1120–1128 doi:10.1038/mt.2008.81 [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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16. ON BEYOND GENDER: REPRESENTATION OF GOD IN THE TORAH AND IN THREE RECENT RENDITIONS INTO ENGLISH.
- Author
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Stein, David E. S.
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TORAH (The Hebrew word) , *HEBREW etymology , *TRANSLATING & interpreting , *GOD in literature , *ENGLISH language - Abstract
Three recently published English translations of the Torah refer to God in unusual ways: They offer the reader the rare experience of encountering the biblical God as a persona who is "beyond" gender. The three renditions, which are of related provenance and presented as "gender accurate" or "gender sensitive," appear in The Torah: A Modern Commentary, revised edition (2005); The Contemporary Torah (2006); and The Torah: A Women's Commentary (2008). Having served as the central member on the translation teams that addressed gender issues, I review considerations for construing God's gender as represented in the Torah. The analysis, based on a reconstruction of ancient plain-sense reading conventions and concepts about deity, explains why a (mostly) gender-neutral translation produces the least distortion of the Torah's God-language. The article then characterizes the three new renditions and their God-language, including the representation of God's name and the rendering of ascriptive imagery. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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17. Creating shared understanding through chats in a community of inquiry
- Author
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Stein, David S., Wanstreet, Constance E., Glazer, Hilda R., Engle, Cheryl L., Harris, Ruth A., Johnston, Susan M., Simons, Mona R., and Trinko, Lynn A.
- Subjects
- *
INTERNET in education , *EDUCATIONAL technology , *TEACHING , *COMPUTERS in education - Abstract
Abstract: This study investigated the process by which shared understanding develops in a chat learning space. It used a practical inquiry model to assess the development of cognitive presence. The study also explored how the pattern of conversation in synchronous discussion supports cognitive presence and how cognitive presence changes over time. Results show that there is a pattern among group members that involves reacquainting themselves through social presence and orienting themselves to the cognitive task through teaching presence. Individual meaning contributed by each member of the group through triggering events and exploratory statements is transformed as members see the text on the screen and respond to it through questioning and collective exploration. This group exploration enables the transition to shared understanding. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
18. Inhibition of dengue virus translation and RNA synthesis by a morpholino oligomer targeted to the top of the terminal 3′ stem–loop structure
- Author
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Holden, Katherine Lynn, Stein, David A., Pierson, Theodore C., Ahmed, Asim A., Clyde, Karen, Iversen, Patrick L., and Harris, Eva
- Subjects
- *
NUCLEIC acids , *HUMAN services , *PUBLIC health , *MESSENGER RNA - Abstract
Abstract: Dengue virus (DEN) is a major public health problem worldwide and causes a spectrum of diseases, for which no antiviral treatments exist. Peptide-conjugated phosphorodiamidate morpholino oligomers (P-PMOs) complementary to the DEN 5′ stem–loop (5′SL) and to the DEN 3′ cyclization sequence (3′CS) inhibit DEN replication, presumably by blocking critical RNA–RNA or RNA–protein interactions involved in viral translation and/or RNA synthesis. Here, a third P-PMO, complementary to the top of the 3′ stem–loop (3′SLT), inhibited DEN replication in BHK cells. Using a novel DEN2 reporter replicon and a DEN2 reporter mRNA, we determined that the 5′SL P-PMO inhibited viral translation, the 3′CS P-PMO blocked viral RNA synthesis but not viral translation, and the 3′SLT P-PMO inhibited both viral translation and RNA synthesis. These results show that the 3′CS and the 3′SL domains regulate DEN translation and RNA synthesis and further demonstrate that P-PMOs are potentially useful as antiviral agents. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
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19. Inhibition, Escape, and Attenuated Growth of Severe Acute Respiratory Syndrome Coronavirus Treated with Antisense Morpholino Oligomers.
- Author
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Neuman, Benjamin W., Stein, David A., Kroeker, Andrew D., Churchill, Michael J., Kim, Alice M., Kuhn, Peter, Dawson, Philip, Moulton, Hong M., Bestwick, Richard K., Iversen, Patrick L., and Buchmeier, Michael J.
- Subjects
- *
SARS disease , *CORONAVIRUSES , *CORONAVIRUS diseases , *DISEASE management , *ANTISENSE nucleic acids , *OLIGOMERS , *VIRUS diseases - Abstract
The recently emerged severe acute respiratory syndrome coronavirus (SARS-CoV) is a potent pathogen of humans and is capable of rapid global spread. Peptide-conjugated antisense morpholino oligomers (P-PMO) were designed to bind by base pairing to specific sequences in the SARS-CoV (Tor2 strain) genome. The P-PMO were tested for their capacity to inhibit production of infectious virus as well as to probe the function of conserved viral RNA motifs and secondary structures. Several virus-targeted P-PMO and a random-sequence control P-PMO showed low inhibitory activity against SARS coronavirus. Certain other virus-targeted P-PMO reduced virus-induced cytopathology and cell-to-cell spread as a consequence of decreasing viral amplification. Active P-PMO were effective when administered at any time prior to peak viral synthesis and exerted sustained antiviral effects while present in culture medium. P-PMO showed low nonspecific inhibitory activity against translation of nontargeted RNA or growth of the arenavirus lymphocytic choriomeningitis virus. Two P-PMO targeting the viral transcription-regulatory sequence (TRS) region in the 5' untranslated region were the most effective inhibitors tested. After several viral passages in the presence of a TRS-targeted P-PMO, partially drug-resistant SARS-CoV mutants arose which contained three contiguous base point mutations at the binding site of a TRS-targeted P-PMO. Those partially resistant viruses grew more slowly and formed smaller plaques than wild-type SARS-CoV. These results suggest PMO compounds have powerful therapeutic and investigative potential toward coronavirus infection. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
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20. Summary Street: Interactive Computer Support for Writing.
- Author
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Wade-Stein, David and Kintsch, Eileen
- Subjects
- *
INTERACTIVE computer systems , *COMPUTER systems , *ONLINE data processing , *QUESTION answering systems , *INSTRUCTIONAL systems , *COMPUTER software , *COMPUTER software industry - Abstract
Summary Street is educational software based on latent semantic analysis (LSA), a computer method for representing the content of texts. The classroom trial described here demonstrates the power of LSA to support an educational goal by providing automatic feedback on the content of students' summaries. Summary Street provides this feedback in an easy-to-grasp, graphic display that helps students to improve their writing across multiple cycles of writing and revision on their own before receiving a teacher's final evaluation. The software thus has the potential to provide students with extensive writing practice without increasing the teacher's workload. In classroom trials 6th-grade students not only wrote better summaries when receiving content-based feedback from Summary Street, but also spent more than twice as long engaged in the writing task. Specifically, their summaries were characterized by a more balanced coverage of the content than summaries composed without this feedback. Greater improvement in content scores was observed with texts that were difficult to summarize. Classroom implementation of Summary Street is discussed, including suggestions for instructional activities beyond summary writing. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
21. Antisense Morpholino-Oligomers Directed against the 5′ End of the Genome Inhibit Coronavirus Proliferation and Growth.
- Author
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Neuman, Benjamin W., Stein, David A., Kroeker, Andrew D., Paulin, Amy D., Moulton, Hong M., Iversen, Patrick L., and Buchmeier, Michael J.
- Subjects
- *
ANTISENSE peptides , *OLIGOMERS , *GENOMES , *PEPTIDES , *VIRUS inactivation , *CORONAVIRUS diseases , *VIROLOGY - Abstract
Conjugation of a peplide related to the human immunodeficiency virus type l Tat represents a novel method for delivery, of antisense morpholino-oligomers. Conjugated and unconjugated oligomers were tested to determine sequence-specific antiviral efficacy against a member of the Coronaviridae, Mouse hepatitis virus (MHV). Specific anlisense activity designed to block translation of the viral replicase polyprotein was first confirmed by reduction of luciferase expression from a target sequence-containing reporter construct in both cell-free and transfected cell culture assays. Peptide-conjugated morpholino-oligomers exhibited low toxicity in DBT astrocytoma cells used for culturing MHV. Oligomer administered at micromolar concentrations was delivered to >80% of ceils and inhibited virus titers 10- to 100-fold in a sequence-specific and dose-responsive manner. In addition, targeted viral protein synthesis, plaque diameter, and cytopathic effect were significantly reduced. Inhibition of virus infectivity by peptide-conjugated morpholino was comparable to the antiviral activity of the aminoglycoside hygrumycin B used at a concentration fivefold higher than the oligomer. These results suggest that this composition of anlisense compound has therapeutic potential for control of coronavirus infection. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
22. A remarkable new species of Psednos (Teleostei: Liparidae) from the western North Atlantic Ocean.
- Author
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Chernova, Natalia V. and Stein, David L.
- Subjects
- *
LYMANTRIIDAE , *VERTEBRATES , *FISHES , *SPECIES , *AQUATIC animals - Abstract
Psednos rossi new species (Teleostei: Liparidae) is described from two specimens collected in the North Atlantic Ocean off Cape Hatteras, North Carolina, at depths of 500-674 m. Psednos rossi belongs to the P. christinae group, which includes six other species and is characterized by 46-47 vertebrae and the absence of a coronal pore. Psednos rossi differs from those six species by having characters unique within the genus: straight spine, body not humpbacked at the occiput, and a very large mouth with a vertical oral cleft. Other distinguishing characters include a notched pectoral fin with 15-16 rays, eye 17-19% SL, and color in life orange-rose. With P. rossi, the genus Psednos as currently known includes 26 described and five undescribed species of small meso- or bathypelagic liparids from the Atlantic, Pacific, and Indian Oceans. [ABSTRACT FROM AUTHOR]
- Published
- 2004
23. Liparis adiastolus (Teleostei, Liparidae): A New Snailfish Species from the Littoral Zone of the Northeastern Pacific, and Redescription of Liparis rutteri (Gilbert and Snyder, 1898).
- Author
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Stein, David L., Bond, Carl E., and Misitano, David
- Subjects
- *
LIPARIS (Fish) , *FISH anatomy , *VERTEBRAE - Abstract
Liparis adiastolus, a previously undescribed species from the coasts of Oregon and Washington, northwest United States, is described. The new species has probably been consistently confused with Liparis rutteri, which has a more northerly distribution. Liparis adiastolus is clearly distinguishable from all similar species in having 41-70 pyloric caeca, 35-39 vertebrae, 30-33 dorsal-fin rays, 32-35 pectoral-fin rays, disk 67-77% HL, and other distinctive characters. In addition to describing the new species, we select a lectotype of L. rutteri, provide an expanded diagnosis for that species, and discuss the confusion previously existing with regard to its identification. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
24. A Robust Exponential Mixture Detector Applied to Radar.
- Author
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Stein, David W. J.
- Subjects
- *
RADAR , *EXPONENTIAL generating functions - Abstract
Presents information on a study on exponential mixture probability density functions which proved to be useful models of radar sea clutter. Univariate models of sea clutter intensity; Detection algorithms; Evaluation of the performance of algorithms by using radar data.
- Published
- 1999
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25. Health Watch 2000: Community Health Assessment in South Central Ohio.
- Author
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Stanley, Sharon A.R. and Stein, David S.
- Subjects
- *
NURSING assessment , *COMMUNITY health nursing - Abstract
In Ohio, there has been a recent but concerted effort from the state health department down through the local health departments to complete community health assessment studies for the prioritization and delivery of health services in their respective communities. At the same time, the Joint Commission on Accreditation of Health Care Organizations has been actively encouraging hospitals to assess targeted communities prior to the delivery of community-based services. In a changing health care system that demands greater emphasis on health promotion and disease prevention, new alliances are born of necessity, with collaborative products and benefits to all involved. A local health department and a community hospital in south central Ohio that was jointly owned by the city and county, in consultation with a neighboring state university, embarked on a 1 1/2-year study to define, prioritize, and plan service delivery for the community through Health Watch 2000. Six priority health areas based on national health objectives were determined along with subsequent health planning recommendations, leading to the ultimate goal of healthy people in healthy communities. [ABSTRACT FROM AUTHOR]
- Published
- 1998
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26. Drosophila Myc is oncogenic in mammalian cells and plays a role in the diminutive phenotype.
- Author
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Schreiber, Nicole and Stein, David
- Subjects
- *
DROSOPHILA - Abstract
Presents a study indicating that Drosophila Myc is oncogenic in mammalian cells and plays a role in the diminutive phenotype. Hybrid screens and structural analysis of interacting proteins; REF cooperation assays and expression constructs; In situ hybridizations.
- Published
- 1997
- Full Text
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27. Scheduling Dial-a-Ride Transportation Systems.
- Author
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Stein, David M.
- Subjects
- *
PARATRANSIT services , *PRODUCTION scheduling , *TRANSPORTATION , *ALGORITHMS , *MATHEMATICAL models , *FOUNDATIONS of arithmetic , *URBAN transportation - Abstract
An analytic investigation into the fundamental aspects of scheduling "Dial-a-Ride" transportation systems is conducted. Based upon simple mathematical models that focus on the combinatorial nature of the problem, a class of algorithms is derived for which performance can be measured in a precise asymptotic probabilistic sense. The approach yields many qualitative insights and the resulting transportation schemes have many attractive practiced features. For example, they have modest computational requirements, are decentralized, and are early to visualize and implement. [ABSTRACT FROM AUTHOR]
- Published
- 1978
- Full Text
- View/download PDF
28. Profile of the 2016 dengue outbreak in Nepal.
- Author
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Khetan, Ramawatar Prasad, Stein, David A., Chaudhary, Santosh Kumar, Rauniyar, Ramanuj, Upadhyay, Bishnu Prasad, Gupta, Umesh Prasad, and Gupta, Birendra Prasad
- Subjects
- *
DENGUE viruses , *PUBLIC health , *DENGUE , *DISEASE outbreaks , *MOSQUITO vectors , *PATIENTS - Abstract
Objective: The objective of this study was to obtain clinical, virological and demographic data detailing the 2016 dengue outbreak in Nepal. Results: Dengue disease was first reported in Nepal in 2004 and several major outbreaks have occurred since then, with a significant impact on public health. An outbreak of dengue fever occurred in Nepal during June to November 2016, with a peak number of cases reported in September. 1473 patients with laboratory confirmed DENV infections visited or were admitted to hospitals during this period. The most common clinical symptoms included fever, headache, joint pain and thrombocytopenia. Serotyping of 75 serum samples from patients having fever for less than 4 days was carried out with a dengue virus (DENV) serotype-specific RT-PCR strategy. Our results indicate that the dengue outbreak in Nepal during 2016 was caused predominantly, if not exclusively, by DENV-1, representing a shift in the prevailing serotype from DENV-2, the dominant serotype characterizing the 2013 dengue epidemic in Nepal. Hopefully, this report will assist Nepalese public health agencies in developing improved dengue-related programs including mosquito-vector control, DENV surveillance, and diagnosis and treatment of dengue fever patients, in order to reduce the impact of future dengue epidemics. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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29. Monoclonal War: The Antibody Arsenal and Targets for Expanded Application.
- Author
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Rosenn, Eric H., Benhaim, Mickael, Siegel, Allison, Stein, David A., Leonard, Joseph S., Katcher, Erik, Halperin, Dania, and Mostel, Zachary
- Subjects
- *
MONOCLONAL antibodies , *MULTIDRUG resistance , *CANCER cells , *NEURODEGENERATION , *ARSENALS - Abstract
Advancements in sequencing and screening technology have made monoclonal antibodies more accessible, cost-effective, and precise. These drugs effectively target pathogens and cancer cells and even regulate metabolic pathways by focusing on specific intermediates. Monoclonal antibodies play a key role in mitigating a rise in occupation-related cancers, neurodegenerative disorders, and multidrug-resistant organisms. Here, we review the origins, mechanisms, and applications of this important drug class and explore future avenues for research. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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30. A Spectre Is Haunting Law and Society: Revisiting Radical Criminology at UC Berkeley.
- Author
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Stein, David
- Subjects
- *
CRIMINOLOGY education in universities & colleges - Abstract
The article describes a course designed by Jonathan Simon and Tony Platt titled "From Community Control to Mass Incarceration: Legacies of 1970s Criminology" they introduced at University of California Berkeley.
- Published
- 2013
31. Persistence of HIV Drug Resistance Mutations: More Clues from Clinical Observations.
- Author
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Jenny-Avital, Elizabeth R. and Stein, David K.
- Subjects
- *
LETTERS to the editor , *DRUG resistance - Abstract
Presents a letter to the editor about the persistence of HIV drug resistance mutations.
- Published
- 2004
- Full Text
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32. Reconstitution of Torso signaling in cultured cells suggests a role for both Trunk and Torso-like in receptor activation.
- Author
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Amarnath, Smita, Stevens, Leslie M., and Stein, David S.
- Subjects
- *
TORSO , *PROTEIN-tyrosine kinases , *DROSOPHILA - Abstract
Formation of the Drosophila embryonic termini is controlled by the localized activation of the receptor tyrosine kinase Torso. Both Torso and Torso's presumed ligand, Trunk, are expressed uniformly in the early embryo. Polar activation of Torso requires Torso-like, which is expressed by follicle cells adjacent to the ends of the developing oocyte. We find that Torso expressed at high levels in cultured Drosophila cells is activated by individual application of Trunk, Torsolike or another known Torso ligand, Prothoracicotropic Hormone. In addition to assays of downstream signaling activity, Torso dimerization was detected using bimolecular fluorescence complementation. Trunk and Torso-like were active when co-transfected with Torso and when presented to Torso-expressing cells in conditioned medium. Trunk and Torso-like were also taken up from conditioned medium specifically by cells expressing Torso. At low levels of Torso, similar to those present in the embryo, Trunk and Torso-like alone were ineffective but acted synergistically to stimulate Torso signaling. Our results suggest that Torso interacts with both Trunk and Torso-like, which cooperate to mediate dimerization and activation of Torso at the ends of the Drosophila embryo. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
33. Inhibition of Foot-and-Mouth Disease Virus Infections in Cell Cultures with Antisense Morpholino Oligomers.
- Author
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Vagnozzi, Ariel, Stein, David A., Iversen, Patrick L., and Rieder, Elizabeth
- Subjects
- *
FOOT & mouth disease virus , *FOOT & mouth disease prevention , *CELL culture , *OLIGOMERS , *ANTIVIRAL agents - Abstract
Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed ungulates that can lead to severe losses in the livestock production and export industries. Although vaccines have been extensively used to control FMD, there is no antiviral therapy available to treat ongoing infections with FMD virus (FMDV). Six peptide-conjugated morpholino oligomers (PPMOs) with sequences complementary to various 21-nucleotide segments of the 5' and 3' untranslated regions (UTRs) of the FMDV genome (strain A24 Cruzeiro/Brazil/1955 [A24Cru]) were evaluated in cell cultures. Three of the PPMOs, targeting domain 5 of the internal ribosome entry site (5D PPMO), and the two translation start codon regions (AUG1 and AUG2 PPMOs), showed high levels of anti-FMDV activity. A dose-dependent and sequence-specific reduction in viral titers of greater than 5 log10, with a concomitant reduction of viral protein and RNA expression, was achieved at low micromolar concentrations. Under identical conditions, three other PPMOs targeting the 5'-terminal region of the genome, the cis-acting replication element in the 5' UTR, and the 3' "ab" stem-loop showed less dramatic titer reductions of 1.5 log10 to 2 log10. Treatment with 5D PPMO reduced the titers of FMDV strains representing five different serotypes by 2 log10 to 4 log10 compared to those of the controls. A24Cru-infected BHK-21 cells treated repeatedly with 5D or AUG2 PPMO generated resistant viruses for which phenotypic and genotypic properties were defined. Notably, three passages with low concentrations of the AUG1 PPMO extinguished all traces of detectable virus. The results indicate that PPMOs have potential for treating FMDV infections and that they also represent useful tools for studying picornaviral translation and evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
34. Inhibition of Coxsackievirus B3 in Cell Cultures and in Mice by Peptide-Conjugated Morpholino Oligomers Targeting the Internal Ribosome Entry Site.
- Author
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Ji Yuan, Stein, David A., Lim, Travis, Dexin Qiu, Coughlin, Shaun, Zhen Liu, Yinjing Wang, Blouch, Robert, Moulton, Hong M., Iversen, Patrick L., and Decheng Yang
- Subjects
- *
COXSACKIEVIRUS diseases , *COXSACKIEVIRUSES , *MYOCARDITIS , *NUCLEIC acids , *OLIGOMERS , *HELA cells - Abstract
Coxsackievirus B3 (CVB3) is a primary cause of viral myocarditis, yet no effective therapeutic against CVB3 is available. Nucleic acid-based interventional strategies against various viruses, including CVB3, have shown promise experimentally, but limited stability and inefficient delivery in vivo remain as obstacles to their potential as therapeutics. We employed phosphorodiamidate morpholino oligomers (PMO) conjugated to a cell-penetrating arginine-rich peptide, P007 (to form PPMO), to address these issues. Eight CVB3-specific PPMO were evaluated with HeLa cells and HL-1 cardiomyocytes in culture and in a murine infection model. One of the PPMO (PPMO-6), designed to target a sequence in the 3′ portion of the CVB3 internal ribosomal entry site, was found to be especially potent against CVB3. Treatment of cells with PPMO-6 prior to CVB3 infection produced an approximately 3-log10 decrease in viral titer and largely protected cells from a virus-induced cytopathic effect. A similar antiviral effect was observed when PPMO-6 treatment began shortly after the virus infection period. A/J mice receiving intravenous administration of PPMO-6 once prior to and once after CVB3 infection showed an ∼ 2-log10-decreased viral titer in the myocardium at 7 days postinfection and a significantly decreased level of cardiac tissue damage, compared to the controls. Thus, PPMO-6 provided potent inhibition of CVB3 amplification both in cell cultures and in vivo and appears worthy of further evaluation as a candidate for clinical development. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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- View/download PDF
35. Drosophila Dok is required for embryonic dorsal closure.
- Author
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Biswas, Romi, Stein, David, and Stanley, E. Richard
- Subjects
- *
DROSOPHILA , *MORPHOGENESIS , *EMBRYOLOGY , *EPIDERMIS , *TYROSINE - Abstract
Embryonic dorsal closure (DC) in Drosophila is a series of morphogenetic movements involving the bilateral dorsal movement of the epidermis (cell stretching) and dorsal suturing of the leading edge (LE) cells to enclose the viscera. The Syk family tyrosine kinase Shark plays a crucial role in this Jun amino-terminal kinase (JNK)-dependent process, where it acts upstream of JNK in LE cells. Using a yeast two-hybrid screen, the unique Drosophila homolog of the downstream of kinase (Dok) family, Ddok, was identified by its ability to bind Shark SH2 domains in a tyrosine phosphorylation-dependent fashion. In cultured S2 embryonic cells, Ddok tyrosine phosphorylation is Src dependent; Shark associates with Ddok and Ddok localizes at the cell cortex, together with a portion of the Shark protein. The embryonic expression pattern of Ddok resembles the expression pattern of Shark. Ddok loss-of-function mutant (DdokPG155) germ-line clones possess DC defects, including the loss of JNK-dependent expression of dpp mRNA in LE cells, and decreased epidermal F-actin staining and LE actin cable formation. Epistatic analysis indicates that Ddok functions upstream of shark to activate JNK signaling during DC. Consistent with these observations, Ddok mutant embryos exhibit decreased levels of tyrosine phosphorylated Shark at the cell periphery of LE and epidermal cells. As there are six mammalian Dok family members that exhibit some functional redundancy, analysis of the regulation of DC by Ddok is expected to provide novel insights into the function of the Dok adapter proteins. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
36. Dorsoventral Patterning: A Direct Route from Ovary to Embryo
- Author
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Amiri, Anahita and Stein, David
- Subjects
- *
PATTERN formation (Biology) , *EPIDERMAL growth factor , *CELL receptors , *EMBRYOLOGY - Abstract
Recent data indicate that Gurken-mediated activation of the EGF receptor in the somatic follicle cells of the Drosophila ovary – required for dorsoventral patterning of the fly embryo – leads to cell-autonomous repression of pipe expression, suggesting that the EGF receptor signaling pathway acts directly to control pipe transcription. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
37. Rapid testing for CVDs: high-sensitivity troponin assays.
- Author
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Stein, David
- Subjects
- *
BIOMARKERS , *EMERGENCY medical services , *TIME , *CONTINUING education units , *EARLY diagnosis , *TROPONIN ,MYOCARDIAL infarction diagnosis - Abstract
The article discusses risk of cardiovascular diseases (CVDs) and states that high-sensitivity troponin assays improve diagnostic accuracy and rapid detection of myocardial infarction (MI). It also discusses the loss of cardiac troponins and necessity of serum troponin for establishing a diagnosis of ML. It also discusses advances in immunoassay technologies and the international adoption of traceable troponin calibration standards which have resulted in development of troponin.
- Published
- 2013
38. Pipe-Dependent Ventral Processing of Easter by Snake Is the Defining Step in Drosophila Embryo DV Axis Formation
- Author
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Cho, Yong Suk, Stevens, Leslie M., and Stein, David
- Subjects
- *
DROSOPHILA genetics , *EMBRYOLOGY , *CELL receptors , *LIGANDS (Biochemistry) , *SULFOTRANSFERASES , *PROTEINS , *PROTEOLYTIC enzymes , *PROTEOLYSIS - Abstract
Summary: The establishment of Drosophila embryonic dorsal-ventral (DV) polarity relies on serine proteolytic activity in the perivitelline space between the embryonic membrane and the eggshell []. Gastrulation Defective cleaves and activates Snake, which processes and activates Easter, which cleaves Spätzle to form the activating ligand for the Toll receptor. Ventral restriction of ligand formation depends on the Pipe sulfotransferase, which is expressed in ventral cells of the follicular epithelium surrounding the developing oocyte []. Pipe modifies components of the developing eggshell to produce a ventral cue embedded in the vitelline membrane []. This ventral cue is believed to promote one or more of the proteolysis steps in the perivitelline space. By examining the processing of transgenic, tagged versions of the perivitelline proteins during DV patterning, we find that the proteolysis of Easter by Snake is the first Pipe-dependent step and therefore the key ventrally restricted event in the protease cascade. We also find that Snake and Easter associate together in a complex in both wild-type and pipe mutant-derived embryos. This observation suggests a mechanism in which the sulfated target of Pipe promotes a productive interaction between Snake and Easter, perhaps by facilitating conformational changes in a complex containing the two proteins. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
39. Sulfation of Eggshell Components by Pipe Defines Dorsal-Ventral Polarity in the Drosophila Embryo
- Author
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Zhang, Zhenyu, Stevens, Leslie M., and Stein, David
- Subjects
- *
EGGSHELLS , *MOLECULAR biology , *EMBRYOS , *DROSOPHILA , *SULFOTRANSFERASES , *DEVELOPMENTAL biology - Abstract
Summary: Drosophila embryonic dorsal-ventral (DV) polarity is controlled by a group of sequentially acting serine proteases located in the fluid-filled perivitelline space between the embryonic membrane and the eggshell, which generate the ligand for the Toll receptor on the ventral side of the embryo . Spatial control of the protease cascade relies on the Pipe sulfotransferase, a fly homolog of vertebrate glycosaminoglycan-modifying enzymes , which is expressed in ventral cells of the follicular epithelium surrounding the developing oocyte. Here we show that the vitelline membrane-like (VML) protein undergoes Pipe-dependent sulfation and, consistent with a role in conveying positional information from the egg chamber to the embryo, becomes incorporated into the eggshell at a position corresponding to the location of the follicle cells from which it was secreted. Although VML influences embryonic DV pattern in a sensitized genetic background, VML is not essential for DV axis formation, suggesting that there is redundancy in the composition of the Pipe enzymatic target. Correspondingly, we find that additional structural components of the vitelline membrane undergo Pipe-dependent sulfation. In identifying the elusive targets of Pipe, this work points to the vitelline membrane as the source of signals that generate the Drosophila DV axis. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
40. Co-selection of West Nile virus nucleotides that confer resistance to an antisense oligomer while maintaining long-distance RNA/RNA base pairings
- Author
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Zhang, Bo, Dong, Hongping, Stein, David A., and Shi, Pei-Yong
- Subjects
- *
WEST Nile virus , *ANTISENSE peptides , *RNA viruses , *NUCLEOTIDES , *OLIGOMERS , *VIRAL genomes , *MUTAGENESIS - Abstract
Abstract: West Nile virus (WNV) genome cyclization is mediated by two pairs of long-distance RNA/RNA interactions: the 5′CS/3′CSI (conserved sequence) and the 5′UAR/3′UAR (upstream AUG region) base pairings. Antisense peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs), designed to interfere with the 5′CS/3′CSI or 5′UAR/3′UAR base pairings, were previously shown to inhibit WNV. In this study, we selected and characterized WNVs resistant to a PPMO targeting the 3′UAR (3′UAR-PPMO). All resistant viruses accumulated one-nucleotide mutations within the 3′UAR, leading to a single-nucleotide mismatch or a weakened base-pairing interaction with the 3′UAR-PPMO. Remarkably, a one-nucleotide mutation within the 5′UAR was correspondingly co-selected; the 5′UAR mutation restored the base pairing with the 3′UAR mutation. Mutagenesis of WNV demonstrated that the single-nucleotide change within the 3′UAR-PPMO-target site conferred the resistance. RNA binding analysis indicated that the single-nucleotide change reduced the ability of 3′UAR-PPMO to block the RNA/RNA interaction required for genome cyclization. The results suggest a mechanism by which WNV develops resistance to 3′UAR-PPMO, through co-selection of the 5′UAR and 3′UAR, to create a mismatch or a weakened base-pairing interaction with the PPMO, while maintaining the 5′UAR/3′UAR base pairings. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
41. Inhibition of alphavirus infection in cell culture and in mice with antisense morpholino oligomers
- Author
-
Paessler, Slobodan, Rijnbrand, Rene, Stein, David A., Ni, Haolin, Yun, Nadezhda E., Dziuba, Natallia, Borisevich, Viktoriya, Seregin, Alexey, Ma, Yinghong, Blouch, Robert, Iversen, Patrick L., and Zacks, Michele A.
- Subjects
- *
OLIGOMERS , *RNA , *GENOMES , *TISSUE culture - Abstract
Abstract: The genus Alphavirus contains members that threaten human health, both as natural pathogens and as potential biological weapons. Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMO) enter cells readily and can inhibit viral replication through sequence-specific steric blockade of viral RNA. Sindbis virus (SINV) has low pathogenicity in humans and is regularly utilized as a model alphavirus. PPMO targeting the 5′-terminal and AUG translation start site regions of the SINV genome blocked the production of infectious SINV in tissue culture. PPMO designed against corresponding regions in Venezuelan equine encephalitis virus (VEEV) were likewise found to be effective in vitro against several strains of VEEV. Mice treated with PPMO before and after VEEV infection were completely protected from lethal outcome while mice receiving only post-infection PPMO treatment were partially protected. Levels of virus in tissue samples correlated with animal survival. Uninfected mice suffered no apparent ill-effects from PPMO treatment. Thus, PPMO appear promising as candidates for therapeutic development against alphaviruses. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
42. West Nile virus genome cyclization and RNA replication require two pairs of long-distance RNA interactions
- Author
-
Zhang, Bo, Dong, Hongping, Stein, David A., Iversen, Patrick L., and Shi, Pei-Yong
- Subjects
- *
WEST Nile virus , *GENOMES , *NUCLEIC acids , *DNA replication - Abstract
Abstract: West Nile virus (WNV) genome cyclization and replication require two pairs of long-distance RNA interactions. Besides the previously reported 5′CS/3′CSI (conserved sequence) interaction, a 5′UAR/3′UAR (upstream AUG region) interaction also contributes to genome cyclization and replication. WNVs containing mutant 5′UARs capable of forming the 5′/3′ viral RNA interaction were replicative. In contrast, WNV containing a 5′UAR mutation that abolished the 5′/3′ viral RNA interaction was non-replicative; however, the replication defect could be rescued by a single-nucleotide adaptation that restored the 5′/3′ RNA interaction. The 5′UAR/3′UAR interaction is critical for RNA synthesis, but not for viral translation. Antisense oligomers targeting the 5′UAR/3′UAR interaction effectively inhibited WNV replication. Phylogenic analysis showed that the 3′UAR could alternate between pairing with the 5′UAR or with the 3′ end of the flaviviral genome. Therefore, the 5′UAR/3′UAR pairing may release the 3′ end of viral genome (as a template) during the initiation of minus-strand RNA synthesis. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
43. Putting the "e" in FDA'S Draft PRO Guidance.
- Author
-
Wenzel, Keith, Byrom, Bill, and Stein, David
- Subjects
- *
HEALTH outcome assessment , *EVALUATION of medical care , *CLINICAL prediction rules - Abstract
The article reports that the U.S. Food and Drug Administration's draft guidance, Patient-Reported Outcome Measures: Use in Medical Product Development to Support Labeling Claims, has marked the formal positioning of the agency's stance regarding patient reported outcomes (PROs) in clinical trials. The guidance is an important document in that it provides a single point of reference for the agency's thinking on the topic.
- Published
- 2007
44. Hemagglutinins of Avian Influenza Viruses Are Proteolytically Activated by TMPRSS2 in Human and Murine Airway Cells.
- Author
-
Bestle, Dorothea, Limburg, Hannah, Kruhl, Diana, Harbig, Anne, Stein, David A., Moulton, Hong, Matrosovich, Mikhail, Abdelwhab, Elsayed M., Stech, Jürgen, and Böttcher-Friebertshäuser, Eva
- Subjects
- *
AVIAN influenza A virus , *AVIAN influenza , *HEMAGGLUTININ , *INFLUENZA A virus , *INFLUENZA , *INFLUENZA viruses , *PROTEOLYTIC enzymes , *LUNGS - Abstract
Cleavage of the influenza A virus (IAV) hemagglutinin (HA) by host proteases is indispensable for virus replication. Most IAVs possess a monobasic HA cleavage site cleaved by trypsin-like proteases. Previously, the transmembrane protease TMPRSS2 was shown to be essential for proteolytic activation of IAV HA subtypes H1, H2, H7, and H10 in mice. In contrast, additional proteases are involved in activation of certain H3 IAVs, indicating that HAs with monobasic cleavage sites can differ in their sensitivity to host proteases. Here, we investigated the role of TMPRSS2 in proteolytic activation of avian HA subtypes H1 to H11 and H14 to H16 in human and mouse airway cell cultures. Using reassortant viruses carrying representative HAs, we analyzed HA cleavage and multicycle replication in (i) lung cells of TMPRSS2-deficient mice and (ii) Calu-3 cells and primary human bronchial cells subjected to morpholino oligomer-mediated knockdown of TMPRSS2 activity. TMPRSS2 was found to be crucial for activation of H1 to H11, H14, and H15 in airway cells of human and mouse. Only H9 with an R-S-S-R cleavage site and H16 were proteolytically activated in the absence of TMPRSS2 activity, albeit with reduced efficiency. Moreover, a TMPRSS2-orthologous protease from duck supported activation of H1 to H11, H15, and H16 in MDCK cells. Together, our data demonstrate that in human and murine respiratory cells, TMPRSS2 is the major activating protease of almost all IAV HA subtypes with monobasic cleavage sites. Furthermore, our results suggest that TMPRSS2 supports activation of IAV with a monobasic cleavage site in ducks. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
45. Light-dependent N-end rule-mediated disruption of protein function in Saccharomyces cerevisiae and Drosophila melanogaster.
- Author
-
Stevens, Leslie M., Kim, Goheun, Koromila, Theodora, Steele, John W., McGehee, James, Stathopoulos, Angelike, and Stein, David S.
- Subjects
- *
DROSOPHILA melanogaster , *SACCHAROMYCES cerevisiae , *TIME of death , *N-terminal residues , *PROTEOLYSIS , *UBIQUITIN ligases - Abstract
Here we describe the development and characterization of the photo-N-degron, a peptide tag that can be used in optogenetic studies of protein function in vivo. The photo-N-degron can be expressed as a genetic fusion to the amino termini of other proteins, where it undergoes a blue light-dependent conformational change that exposes a signal for the class of ubiquitin ligases, the N-recognins, which mediate the N-end rule mechanism of proteasomal degradation. We demonstrate that the photo-N-degron can be used to direct light-mediated degradation of proteins in Saccharomyces cerevisiae and Drosophila melanogaster with fine temporal control. In addition, we compare the effectiveness of the photo-N-degron with that of two other light-dependent degrons that have been developed in their abilities to mediate the loss of function of Cactus, a component of the dorsal-ventral patterning system in the Drosophila embryo. We find that like the photo-N-degron, the blue light-inducible degradation (B-LID) domain, a light-activated degron that must be placed at the carboxy terminus of targeted proteins, is also effective in eliciting light-dependent loss of Cactus function, as determined by embryonic dorsal-ventral patterning phenotypes. In contrast, another previously described photosensitive degron (psd), which also must be located at the carboxy terminus of associated proteins, has little effect on Cactus-dependent phenotypes in response to illumination of developing embryos. These and other observations indicate that care must be taken in the selection and application of light-dependent and other inducible degrons for use in studies of protein function in vivo, but importantly demonstrate that N- and C-terminal fusions to the photo-N-degron and the B-LID domain, respectively, support light-dependent degradation in vivo. Author summary: Much of what we know about biological processes has come from the analysis of mutants whose loss-of-function phenotypes provide insight into their normal functions. However, for genes that are required for viability and which have multiple functions in the life of a cell or organism one can only observe mutant phenotypes produced up to the time of death. Normal functions performed in wild-type individuals later than the time of death of mutants cannot be observed. In one approach to overcoming this limitation, a class of peptide degradation signals (degrons) have been developed, which when fused to proteins-of-interest, can target those proteins for degradation in response to various stimuli (temperature, chemical agents, co-expressed proteins, or light). Here we describe a new inducible degron (the photo-N-degron or PND), which when fused to the N-terminus of a protein, can induce N-end rule-mediated degradation in response to blue-light illumination and have validated its use in both yeast and Drosophila embryos. Moreover, using the Drosophila embryonic patterning protein Cactus, we show that like the PND, the previously-described B-LID domain, but not the previously-described photosensitive degron (psd), can produce detectable light-inducible phenotypes in Drosophila embryos that are consistent with the role of Cactus in dorsal-ventral patterning. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
46. Stoichiometric interactions explain spindle dynamics and scaling across 100 million years of nematode evolution.
- Author
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Farhadifar, Reza, Che-Hang Yu, Fabig, Gunar, Hai-Yin Wu, Stein, David B., Rockman, Matthew, Müller-Reichert, Thomas, Shelley, Michael J., and Needleman, Daniel J.
- Subjects
- *
SPINDLE apparatus , *CELL size , *QUANTITATIVE genetics , *BIOPHYSICS , *MICROTUBULES - Abstract
The spindle shows remarkable diversity, and changes in an integrated fashion, as cells vary over evolution. Here, we provide a mechanistic explanation for variations in the first mitotic spindle in nematodes. We used a combination of quantitative genetics and biophysics to rule out broad classes of models of the regulation of spindle length and dynamics, and to establish the importance of a balance of cortical pulling forces acting in different directions. These experiments led us to construct a model of cortical pulling forces in which the stoichiometric interactions of microtubules and force generators (each force generator can bind only one microtubule), is key to explaining the dynamics of spindle positioning and elongation, and spindle final length and scaling with cell size. This model accounts for variations in all the spindle traits we studied here, both within species and across nematode species spanning over 100 million years of evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
47. DESS deconstructed: Is EDTA solely responsible for protection of high molecular weight DNA in this common tissue preservative?
- Author
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Sharpe, Amy, Barrios, Sonia, Gayer, Sarah, Allan-Perkins, Elisha, Stein, David, Appiah-Madson, Hannah J., Falco, Rosalia, and Distel, Daniel L.
- Subjects
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MOLECULAR weights , *ETHYLENEDIAMINETETRAACETIC acid , *DNA , *MYTILUS edulis , *DIMETHYL sulfoxide , *SALT - Abstract
DESS is a formulation widely used to preserve DNA in biological tissue samples. Although it contains three ingredients, dimethyl sulfoxide (DMSO), ethylenediaminetetraacetic acid (EDTA) and sodium chloride (NaCl), it is frequently referred to as a DMSO-based preservative. The effectiveness of DESS has been confirmed for a variety of taxa and tissues, however, to our knowledge, the contributions of each component of DESS to DNA preservation have not been evaluated. To address this question, we stored tissues of three aquatic taxa, Mytilus edulis (blue mussel), Faxonius virilis (virile crayfish) and Alitta virens (clam worm) in DESS, each component of DESS individually and solutions containing all combinations of two components of DESS. After storage at room temperature for intervals ranging from one day to six months, we extracted DNA from each tissue and measured the percentage of high molecular weight (HMW) DNA recovered (%R) and normalized HMW DNA yield (nY). Here, HMW DNA is defined as fragments >10 kb. For comparison, we also measured the %R and nY of HMW DNA from extracts of fresh tissues and those stored in 95% EtOH over the same time intervals. We found that in cases where DESS performed most effectively (yielding ≥ 20%R of HMW DNA), all solutions containing EDTA were as or more effective than DESS. Conversely, in cases where DESS performed more poorly, none of the six DESS-variant storage solutions provided better protection of HMW DNA than DESS. Moreover, for all taxa and storage intervals longer than one day, tissues stored in solutions containing DMSO alone, NaCl alone or DMSO and NaCl in combination resulted in %R and nY of HMW DNA significantly lower than those of fresh tissues. These results indicate that for the taxa, solutions and time intervals examined, only EDTA contributed directly to preservation of high molecular weight DNA. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
48. TMPRSS2 Is the Major Activating Protease of Influenza A Virus in Primary Human Airway Cells and Influenza B Virus in Human Type II Pneumocytes.
- Author
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Limburg, Hannah, Harbig, Anne, Bestle, Dorothea, Stein, David A., Moulton, Hong M., Jaeger, Julia, Janga, Harshavardhan, Hardes, Kornelia, Koepke, Janine, Schulte, Leon, Koczulla, Andreas Rembert, Schmeck, Bernd, Klenk, Hans-Dieter, and Böttcher-Friebertshäuser, Eva
- Subjects
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INFLUENZA B virus , *INFLUENZA A virus , *NEURAMINIDASE , *HUMAN cell culture , *B cells , *EPITHELIAL cells - Abstract
Cleavage of influenza virus hemagglutinin (HA) by host cell proteases is essential for virus infectivity and spread. We previously demonstrated in vitro that the transmembrane protease TMPRSS2 cleaves influenza A virus (IAV) and influenza B virus (IBV) HA possessing a monobasic cleavage site. Subsequent studies revealed that TMPRSS2 is crucial for the activation and pathogenesis of H1N1pdm and H7N9 IAV in mice. In contrast, activation of H3N2 IAV and IBV was found to be independent of TMPRSS2 expression and supported by an as-yet-undetermined protease(s). Here, we investigated the role of TMPRSS2 in proteolytic activation of IAV and IBV in three human airway cell culture systems: primary human bronchial epithelial cells (HBEC), primary type II alveolar epithelial cells (AECII), and Calu-3 cells. Knockdown of TMPRSS2 expression was performed using a previously described antisense peptideconjugated phosphorodiamidate morpholino oligomer, T-ex5, that interferes with splicing of TMPRSS2 pre-mRNA, resulting in the expression of enzymatically inactive TMPRSS2. T-ex5 treatment produced efficient knockdown of active TMPRSS2 in all three airway cell culture models and prevented proteolytic activation and multiplication of H7N9 IAV in Calu-3 cells and H1N1pdm, H7N9, and H3N2 IAV in HBEC and AECII. T-ex5 treatment also inhibited the activation and spread of IBV in AECII but did not affect IBV activation in HBEC and Calu-3 cells. This study identifies TMPRSS2 as the major HA-activating protease of IAV in human airway cells and IBV in type II pneumocytes and as a potential target for the development of novel drugs to treat influenza infections. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. Isolation of secreted proteins from Drosophila ovaries and embryos through in vivo BirA-mediated biotinylation.
- Author
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Stevens, Leslie M., Zhang, Yuan, Volnov, Yuri, Chen, Geng, and Stein, David S.
- Subjects
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OVARIES , *DROSOPHILA , *CYTOSKELETAL proteins , *EMBRYOS , *OVARIAN follicle , *PROTEINS , *ENDOPLASMIC reticulum - Abstract
The extraordinarily strong non-covalent interaction between biotin and avidin (kD = 10−14–10−16) has permitted this interaction to be used in a wide variety of experimental contexts. The Biotin Acceptor Peptide (BAP), a 15 amino acid motif that can be biotinylated by the E. coli BirA protein, has been fused to proteins-of-interest, making them substrates for in vivo biotinylation. Here we report on the construction and characterization of a modified BirA bearing signals for secretion and endoplasmic reticulum (ER) retention, for use in experimental contexts requiring biotinylation of secreted proteins. When expressed in the Drosophila female germline or ovarian follicle cells under Gal4-mediated transcriptional control, the modified BirA protein could be detected and shown to be enzymatically active in ovaries and progeny embryos. Surprisingly, however, it was not efficiently retained in the ER, and instead appeared to be secreted. To determine whether this secreted protein, now designated secBirA, could biotinylate secreted proteins, we generated BAP-tagged versions of two secreted Drosophila proteins, Torsolike (Tsl) and Gastrulation Defective (GD), which are normally expressed maternally and participate in embryonic pattern formation. Both Tsl-BAP and GD-BAP were shown to exhibit normal patterning activity. Co-expression of Tsl-BAP together with secBirA in ovarian follicle cells resulted in its biotinylation, which permitted its isolation from both ovaries and progeny embryos using Avidin-coupled affinity matrix. In contrast, co-expression with secBirA in the female germline did not result in detectable biotinylation of GD-BAP, possibly because the C-terminal location of the BAP tag made it inaccessible to BirA in vivo. Our results indicate that secBirA directs biotinylation of proteins bound for secretion in vivo, providing access to powerful experimental approaches for secreted proteins-of-interest. However, efficient biotinylation of target proteins may vary depending upon the location of the BAP tag or other structural features of the protein. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
50. Cardiolipin mediates curcumin interactions with mitochondrial membranes.
- Author
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Ben-Zichri, Shani, Kolusheva, Sofiya, Danilenko, Michael, Ossikbayeva, Saniya, Stabbert, William J., Poggio, Juan L., Stein, David E., Orynbayeva, Zulfiya, and Jelinek, Raz
- Subjects
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CARDIOLIPIN , *CURCUMIN , *MITOCHONDRIAL membranes , *TARGETED drug delivery , *PROTEIN-protein interactions - Abstract
Abstract Curcumin, the main molecular ingredient of the turmeric spice, has been reported to exhibit therapeutic properties for varied diseases and pathological conditions. While curcumin appears to trigger multiple signaling pathways, the precise mechanisms accounting for its therapeutic activity have not been deciphered. Here we show that curcumin exhibits significant interactions with cardiolipin (CL), a lipid exclusively residing in the mitochondrial membrane. Specifically, we found that curcumin affected the structures and dynamics of CL-containing biomimetic and biological mitochondrial membranes. Application of several biophysical techniques reveals the CL-promoted association and internalization of curcumin into lipid bilayers. In parallel, curcumin association with CL containing bilayers increased their fluidity and reduced lipid ordering. These findings suggest that membrane modifications mediated by CL interactions may play a role in the therapeutic functions of curcumin, and that the inner mitochondrial membrane in general might constitute a potential drug target. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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