43 results on '"Tom T. Lee"'
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2. Dual antigen–targeted off-the-shelf NK cells show durable response and prevent antigen escape in lymphoma and leukemia
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Frank Cichocki, Jodie P. Goodridge, Ryan Bjordahl, Sajid Mahmood, Zachary B. Davis, Svetlana Gaidarova, Ramzey Abujarour, Brian Groff, Alec Witty, Hongbo Wang, Katie Tuininga, Behiye Kodal, Martin Felices, Greg Bonello, Janel Huffman, Thomas Dailey, Tom T. Lee, Bruce Walcheck, Bahram Valamehr, and Jeffrey S. Miller
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Killer Cells, Natural ,Leukemia ,Neoplasms ,Immunology ,Humans ,Cell Biology ,Hematology ,Antigenic Drift and Shift ,Biochemistry - Abstract
Substantial numbers of B cell leukemia and lymphoma patients relapse due to antigen loss or heterogeneity after anti-CD19 chimeric antigen receptor (CAR) T cell therapy. To overcome antigen escape and address antigen heterogeneity, we engineered induced pluripotent stem cell-derived NK cells to express both an NK cell-optimized anti-CD19 CAR for direct targeting and a high affinity, non-cleavable CD16 to augment antibody-dependent cellular cytotoxicity. In addition, we introduced a membrane-bound IL-15/IL-15R fusion protein to promote in vivo persistence. These engineered cells, termed iDuo NK cells, displayed robust CAR-mediated cytotoxic activity that could be further enhanced with therapeutic antibodies targeting B cell malignancies. In multiple in vitro and xenogeneic adoptive transfer models, iDuo NK cells exhibited robust anti-lymphoma activity. Furthermore, iDuo NK cells effectively eliminated both CD19+ and CD19− lymphoma cells and displayed a unique propensity for targeting malignant cells over healthy cells that expressed CD19, features not achievable with anti-CAR19 T cells. iDuo NK cells combined with therapeutic antibodies represent a promising approach to prevent relapse due to antigen loss and tumor heterogeneity in patients with B cell malignancies.
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- 2022
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3. A chimeric antigen receptor uniquely recognizing MICA/B stress proteins provides an effective approach to target solid tumors
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John Goulding, Wen-I Yeh, Bryan Hancock, Robert Blum, Tianhao Xu, Bi-Huei Yang, Chia-Wei Chang, Brian Groff, Earl Avramis, Mochtar Pribadi, Yijia Pan, Hui-Yi Chu, Shohreh Sikaroodi, Lauren Fong, Nicholas Brookhouser, Thomas Dailey, Miguel Meza, Matthew Denholtz, Evelyn Diaz, Judy Martin, Peter Szabo, Sarah Cooley, Lucas Ferrari de Andrade, Tom T. Lee, Ryan Bjordahl, Kai W. Wucherpfennig, and Bahram Valamehr
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General Medicine - Published
- 2023
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4. Abstract 1138: Detection of genetically engineered iPSC-derived natural killer cells in blood and tissue
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Cara E. Bickers, Judy L. Martin, Steven Castro, Jason Zhang, Thomas Dailey, Eric Sung, Suzanna Gasparian, Jason O'Rourke, Moyar Ge, Tom T. Lee, Janel Huffman, Jode Goodridge, Ryan Bjordahl, Bahram Valamehr, Peter M. Szabo, Lilly Wong, and Sarah Cooley
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Cancer Research ,Oncology - Abstract
Immune cell therapies derived from induced pluripotent stem cells (iPSC) provide a novel opportunity for the treatment of multiple cancer types. Assessment of the persistence and biodistribution of these product candidates requires specific and sensitive methods to detect engineered cells in both liquid and solid biopsies. Here, we present the development and validation of two complimentary nucleic acid-based detection assays for iPSC-derived natural killer (iNK) cell product candidates containing Fate’s proprietary high-affinity, non-cleavable CD16 transgene (hnCD16). The first assay is a droplet digital PCR (ddPCR) method to detect and quantify hnCD16 transgene copies present in a pool of genomic DNA (gDNA). The primers and probe were designed to recognize the optimized codons of hnCD16. Assay linearity and accuracy were assessed through titration studies using 0.024 to 1 ng of hnCD16-containing DNA spiked into different amounts of hnCD16-negative gDNA. Precision was determined through multiple assay runs by different operators on two instruments. The second assay is an in situ hybridization based method utilizing RNAscope࣪ technology to detect cells expressing hnCD16 in fixed tissue. Probes targeting hnCD16 were used to optimize signal specificity. Cells expressing hnCD16 and tissues from in vivo studies treated with iNK products served as positive controls. For the ddPCR assay, absolute limit of detection (aLoD) was determined to be 4.9 copies of hnCD16 per 20 µL reaction, regardless of total genomic mass input. Absolute limit of quantification (aLoQ) was 12 copies per 20 µL reaction with a %CV ≤30. Relative limit of quantification (rLoQ), assessing transgene to total DNA ratio, is affected by the background gDNA input and is less sensitive with lower input mass. rLoQ for total mass of 70 - 250 ng was 97 - 22 copies/µg gDNA (0.064% - 0.015%) with a %CV ≤30. The sensitivity of this input range allows evaluation of clinical samples with low cellularity. While ddPCR provides robust quantification of the hnCD16 transcript, the RNAscope࣪ assay informs localization of the iNK product. Specificity of the probe was established by confirming its lack of affinity for endogenous CD16 using a variety of human normal and tumor tissues and by staining hnCD16-positive fixed cell pellets and tissues from in vivo studies. In cell pellets, positive RNAscope࣪ signal correlated with the known ratio of transgene positive cells. In murine tissues previously confirmed to contain iNK cell product, the RNAscope࣪ positive staining correlated with NKG2A immunohistochemistry staining, confirming the presence of product NK cells. The combined use of both the ddPCR and RNAscope࣪ assays targeted to hnCD16 allows for detection and quantification of transgene-bearing iNK cells in a wide variety of patient samples including tumor biopsies. Both assays are being utilized for cell detection and quantification in our ongoing clinical trials. Citation Format: Cara E. Bickers, Judy L. Martin, Steven Castro, Jason Zhang, Thomas Dailey, Eric Sung, Suzanna Gasparian, Jason O'Rourke, Moyar Ge, Tom T. Lee, Janel Huffman, Jode Goodridge, Ryan Bjordahl, Bahram Valamehr, Peter M. Szabo, Lilly Wong, Sarah Cooley. Detection of genetically engineered iPSC-derived natural killer cells in blood and tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1138.
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- 2022
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5. A Single Mutation Traps a Half-Sites Reactive Enzyme in Midstream, Explaining Asymmetry in Hydride Transfer
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Janet Finer-Moore, Robert M. Stroud, and Tom T. Lee
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Models, Molecular ,0301 basic medicine ,Biochemistry & Molecular Biology ,Protein Conformation ,Stereochemistry ,Medical Biochemistry and Metabolomics ,Crystallography, X-Ray ,010402 general chemistry ,medicine.disease_cause ,01 natural sciences ,Biochemistry ,Article ,Cofactor ,Substrate Specificity ,Adduct ,Medicinal and Biomolecular Chemistry ,03 medical and health sciences ,Folic Acid ,Models ,Catalytic Domain ,Escherichia coli ,medicine ,Transferase ,Tetrahydrofolates ,chemistry.chemical_classification ,Crystallography ,Binding Sites ,biology ,Hydride ,Molecular ,Active site ,Substrate (chemistry) ,Thymidylate Synthase ,0104 chemical sciences ,030104 developmental biology ,Enzyme ,chemistry ,Mutation ,X-Ray ,Quinazolines ,biology.protein ,Biochemistry and Cell Biology ,Hydrogen - Abstract
In Escherichia coli thymidylate synthase (EcTS), rate-determining hydride transfer from the cofactor 5,10-methylene-5,6,7,8-tetrahydrofolate to the intermediate 5-methylene-2'-deoxyuridine 5'-monophosphate occurs by hydrogen tunneling, requiring precise alignment of reactants and a closed binding cavity, sealed by the C-terminal carboxyl group. Mutations that destabilize the closed conformation of the binding cavity allow small molecules such as β-mercaptoethanol (β-ME) to enter the active site and compete with hydride for addition to the 5-methylene group of the intermediate. The C-terminal deletion mutant of EcTS produced the β-ME adduct in proportions that varied dramatically with cofactor concentration, from 50% at low cofactor concentrations to 0% at saturating cofactor conditions, suggesting communication between active sites. We report the 2.4 Å X-ray structure of the C-terminal deletion mutant of E. coli TS in complex with a substrate and a cofactor analogue, CB3717. The structure is asymmetric, with reactants aligned in a manner consistent with hydride transfer in only one active site. In the second site, CB3717 has shifted to a site where the normal cofactor would be unlikely to form 5-methylene-2'-deoxyuridine 5'-monophosphate, consistent with no formation of the β-ME adduct. The structure shows how the binding of the cofactor at one site triggers hydride transfer and borrows needed stabilization from substrate binding at the second site. It indicates pathways through the dimer interface that contribute to allostery relevant to half-sites reactivity.
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- 2018
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6. The Role of Protein Dynamics in Thymidylate Synthase Catalysis: Variants of Conserved 2‘-Deoxyuridine 5‘-Monophosphate (dUMP)-Binding Tyr-261
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Daniel V. Santi, Tom T. Lee, Prasanna Venkatraman, Zachary E R Newby, Yaoquan Liu, Richard J. Morse, Lu Liu, Janet Finer-Moore, and Robert M. Stroud
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chemistry.chemical_classification ,Mutation ,biology ,Stereochemistry ,Plasma protein binding ,medicine.disease_cause ,Biochemistry ,Thymidylate synthase ,Enzyme ,Protein structure ,chemistry ,medicine ,biology.protein ,Transferase ,Binding site ,Tyrosine - Abstract
The enzyme thymidylate synthase (TS) catalyzes the reductive methylation of 2‘-deoxyuridine 5‘-monophosphate (dUMP) to 2‘-deoxythymidine 5‘-monophosphate. Using kinetic and X-ray crystallography ex...
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- 2006
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7. A Unique RNA Fold in the RumA-RNA-Cofactor Ternary Complex Contributes to Substrate Selectivity and Enzymatic Function
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Tom T. Lee, Robert M. Stroud, and Sanjay Agarwalla
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Models, Molecular ,Macromolecular Substances ,Stereochemistry ,Molecular Conformation ,Crystallography, X-Ray ,Methylation ,General Biochemistry, Genetics and Molecular Biology ,Cofactor ,Substrate Specificity ,Bacterial Proteins ,23S ribosomal RNA ,Catalytic Domain ,Escherichia coli ,Nucleotide ,Base Pairing ,Ternary complex ,chemistry.chemical_classification ,Binding Sites ,Molecular Structure ,biology ,Biochemistry, Genetics and Molecular Biology(all) ,Nucleotides ,Active site ,Substrate (chemistry) ,RNA ,S-Adenosylhomocysteine ,Enzyme ,chemistry ,Biochemistry ,RNA, Ribosomal ,biology.protein ,Nucleic Acid Conformation - Abstract
SummaryA single base (U1939) within E. coli 23S ribosomal RNA is methylated by its dedicated enzyme, RumA. The structure of RumA/RNA/S-adenosylhomocysteine uncovers the mechanism for achieving unique selectivity. The single-stranded substrate is “refolded” on the enzyme into a compact conformation with six key intra-RNA interactions. The RNA substrate contributes directly to catalysis. In addition to the target base, a second base is “flipped out” from the core loop to stack against the adenine of the cofactor S-adenosylhomocysteine. Nucleotides in permuted sequence order are stacked into the site vacated by the everted target U1939 and compensate for the energetic penalty of base eversion. The 3′ hairpin segment of the RNA binds distal to the active site and provides binding energy that contributes to enhanced catalytic efficiency. Active collaboration of RNA in catalysis leads us to conclude that RumA and its substrate RNA may reflect features from the earliest RNA-protein era.
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- 2005
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8. Crystal Structure of RumA, an Iron-Sulfur Cluster Containing E. coli Ribosomal RNA 5-Methyluridine Methyltransferase
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Sanjay Agarwalla, Robert M. Stroud, and Tom T. Lee
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Methyltransferase ,Stereochemistry ,Amino Acid Motifs ,Molecular Sequence Data ,Iron–sulfur cluster ,Biology ,Crystallography, X-Ray ,Protein Structure, Secondary ,chemistry.chemical_compound ,Bacterial Proteins ,23S ribosomal RNA ,Structural Biology ,Escherichia coli ,Transferase ,Amino Acid Sequence ,Molecular Biology ,Oligonucleotide ,RNA ,Methyltransferases ,Ribosomal RNA ,Protein Structure, Tertiary ,Biochemistry ,chemistry ,RNA, Ribosomal ,DNA ,Protein Binding - Abstract
RumA catalyzes transfer of a methyl group from S -adenosylmethionine (SAM) specifically to uridine 1939 of 23S ribosomal RNA in Escherichia coli to yield 5-methyluridine. We determined the crystal structure of RumA at 1.95 A resolution. The protein is organized into three structural domains: The N-terminal domain contains sequence homology to the conserved TRAM motif and displays a five-stranded β barrel architecture characteristic of an oligosaccharide/oligonucleotide binding fold. The central domain contains a [Fe 4 S 4 ] cluster coordinated by four conserved cysteine residues. The C-terminal domain displays the typical SAM-dependent methyltransferase fold. The catalytic nucleophile Cys389 lies in a motif different from that in DNA 5-methylcytosine methyltransferases. The electrostatic potential surface reveals a predominately positively charged area that covers the concave surface of the first two domains and suggests an RNA binding mode. The iron-sulfur cluster may be involved in the correct folding of the protein or may have a role in RNA binding.
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- 2004
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9. His68 and His141 Are Critical Contributors to the Intersubunit Catalytic Site of Adenylosuccinate Lyase of Bacillus subtilis
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Carolyn A. Worby, Roberta F. Colman, Jack E. Dixon, Tom T. Lee, and Zhao-Qin Bao
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Models, Molecular ,Molecular Sequence Data ,Mutant ,Bacillus subtilis ,Biochemistry ,Catalysis ,chemistry.chemical_compound ,Animals ,Humans ,Histidine ,Amino Acid Sequence ,Adenylosuccinate lyase ,chemistry.chemical_classification ,Binding Sites ,Affinity labeling ,biology ,Chemistry ,Circular Dichroism ,Genetic Complementation Test ,Adenylosuccinate Lyase ,Active site ,Substrate (chemistry) ,Hydrogen-Ion Concentration ,biology.organism_classification ,Adenosine Monophosphate ,Recombinant Proteins ,Kinetics ,Enzyme ,Amino Acid Substitution ,Adenylosuccinate ,Chromatography, Gel ,Mutagenesis, Site-Directed ,biology.protein ,Sequence Alignment - Abstract
Mutant adenylosuccinate lyases of Bacillus subtilis were prepared by site-directed mutagenesis with replacements for His141, previously identified by affinity labeling as being in the active site [Lee, T. T., Worby, C., Dixon, J. E., and Colman, R. F. (1997) J. Biol. Chem. 272, 458-465]. Four substitutions (A, L, E, Q) yield mutant enzyme with no detectable catalytic activity, while the H141R mutant is about 10(-)5 as active as the wild-type enzyme. Kinetic studies show, for the H141R enzyme, a Km that is only 3 times that of the wild-type enzyme. Minimal activity was also observed for mutant enzymes with replacements for His68 [Lee, T. T., Worby, C., Bao, Z. -Q., Dixon, J. E., and Colman, R. F. (1998) Biochemistry 37, 8481-8489]. Measurement of the reversible binding of radioactive adenylosuccinate by inactive mutant enzymes with substitutions at either position 68 or 141 shows that their affinities for substrate are decreased by only 10-40-fold. These results suggest that His141, like His68, plays an important role in catalysis, but not in substrate binding. Evidence is consistent with the hypothesis that His141 and His68 function, respectively, as the catalytic base and acid. Circular dichroism spectroscopy and gel filtration chromatography conducted on wild-type and all His141 and His68 mutants reveal that none of the mutant enzymes exhibits major structural changes and that all the enzymes are tetramers. Mixing inactive His141 with inactive His68 mutant enzymes leads to striking increases in catalytic activity. This complementation of mutant enzymes indicates that His141 and His68 come from different subunits to form the active site. A tetrameric structure of adenylosuccinate lyase was constructed by homology modeling based on the known structures in the fumarase superfamily, including argininosuccinate lyase, delta-crystallin, fumarase, and aspartase. The model suggests that each active site is constituted by residues from three subunits, and that His141 and His68 come from two different subunits.
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- 1998
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10. Implication of His68 in the Substrate Site of Bacillus subtilis Adenylosuccinate Lyase by Mutagenesis and Affinity Labeling with 2-[(4-Bromo-2,3-dioxobutyl)thio]adenosine 5‘-monophosphate
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Zhao-Qin Bao, Jack E. Dixon, Tom T. Lee, Carolyn A. Worby, and Roberta F. Colman
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Adenosine monophosphate ,Molecular Sequence Data ,Bacillus subtilis ,Arginine ,Peptide Mapping ,Biochemistry ,Substrate Specificity ,chemistry.chemical_compound ,Cyclic AMP ,Histidine ,Amino Acid Sequence ,Carbon Radioisotopes ,Adenylosuccinate lyase ,chemistry.chemical_classification ,Binding Sites ,Affinity labeling ,biology ,Adenylosuccinate Lyase ,Proteolytic enzymes ,Substrate (chemistry) ,Affinity Labels ,Thionucleotides ,biology.organism_classification ,Enzyme Activation ,Enzyme ,Amino Acid Substitution ,chemistry ,Adenylosuccinate ,Mutagenesis, Site-Directed - Abstract
Adenylosuccinate lyase of Bacillus subtilis is inactivated by 2-[(4-bromo-2,3-dioxobutyl)thio]adenosine 5'-monophosphate (2-BDB-TAMP) at pH 7.0. As the reagent concentration is increased, a maximum rate constant is approached, indicative of reversible enzyme-reagent complex formation (KR = 68 +/- 9 microM) prior to irreversible modification (kmax = 0.081 +/- 0.004 min-1). Complete inactivation occurs concomitant with about 1 mol of 2-BDB-[14C]TAMP incorporated/mol of enzyme subunit. Adenylosuccinate, or a combination of AMP and fumarate, decreases the inactivation rate and reduces incorporation of [14C] reagent, whereas either AMP or fumarate alone is much less effective. These observations suggest that 2-BDB-TAMP attacks the adenylosuccinate binding site. Proteolytic digestion of inactivated enzyme, followed by purification of the digest by HPLC, yields the radioactive peptide Ile62-Ala72, in which Arg67 and His68 are the most likely targets. Thus 2-BDB-TAMP reacts with adenylosuccinate lyase at a site distinct from the His141 attacked by 6-BDB-TAMP (Lee, Worby, Dixon, and Colman (1997) J. Biol. Chem. 272, 458-465). Site-directed mutagenesis was used to construct mutant enzymes with replacements for both Arg67 and His68, and either Arg67 or His68. The R67M mutant enzyme has almost the same specific activity as the wild-type enzyme under standard assay conditions, whereas the single mutant H68Q and double mutant R67M-H68Q enzymes exhibit specific activities that are decreased more than 100-fold. These results indicate that while Arg67 and His68 may both be in the region of the substrate site, only His68 is important for the catalytic activity of B. subtilis adenylosuccinate lyase. A role is proposed for His68 as a general acid-base catalyst.
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- 1998
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11. Identification of His141 in the Active Site of Bacillus subtilis Adenylosuccinate Lyase by Affinity Labeling with 6-(4-Bromo2,3-dioxobutyl)thioadenosine 5′-Monophosphate
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Tom T. Lee, Carolyn A. Worby, Roberta F. Colman, and Jack E. Dixon
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chemistry.chemical_classification ,Affinity labeling ,biology ,Active site ,Peptide ,Cell Biology ,Bacillus subtilis ,biology.organism_classification ,Biochemistry ,body regions ,chemistry.chemical_compound ,Enzyme ,Reaction rate constant ,chemistry ,Adenylosuccinate ,biology.protein ,Adenylosuccinate lyase ,Molecular Biology - Abstract
Adenylosuccinate lyase of Bacillus subtilis is inactivated by 25-400 μM 6-(4-bromo-2,3-dioxobutyl)thioadenosine 5′-monophosphate (6-BDB-TAMP) at pH 7.0 and 25°C. The initial inactivation rate constant exhibits nonlinear dependence on the concentration of 6-BDB-TAMP, implying there is reversible formation of enzyme-reagent complex (KI = 30 ± 4 μM) prior to irreversible modification (kmax = 0.139 ± 0.005 min−1). The tetrameric enzyme incorporates about 1 mol of 6-BDB-[32P]TAMP per mol of enzyme subunit concomitant with complete inactivation. Protection against inactivation and incorporation of [32P]reagent is provided by adenylosuccinate or a combination of AMP and fumarate, whereas either AMP or fumarate alone is much less effective. These observations suggest that 6-BDB-TAMP targets the adenylosuccinate-binding site. Hydrolyzed 6-BDB-TAMP is a competitive inhibitor with respect to adenylosuccinate in the catalytic reaction and also decreases the rate of inactivation by 6-BDB-TAMP. These results account for the decrease in the inactivation rate as the reaction of 6-BDB-TAMP with the enzyme proceeds. Purification by chromatography on dihydroxyboryl-agarose and high performance liquid chromatography of the tryptic digest of inactivated enzyme yields a single radioactive peptide, Thr140-Phe150, as determined by gas-phase sequencing. Modified His141 is the reaction product of 6-BDB-TAMP and adenylosuccinate lyase. We conclude that 6-BDB-TAMP functions as a reactive adenylosuccinate analog in modifying His141 in the substrate-binding site of adenylosuccinate lyase, where it may serve as a general base accepting a proton from the succinyl group during catalysis.
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- 1997
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12. Structure of a TrmA-RNA complex: A consensus RNA fold contributes to substrate selectivity and catalysis in m5U methyltransferases
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Akram Alian, Tom T. Lee, Robert M. Stroud, Janet Finer-Moore, and Sarah L. Griner
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Models, Molecular ,Protein Folding ,Base pair ,Stereochemistry ,Molecular Sequence Data ,Models, Biological ,Catalysis ,Protein Structure, Secondary ,Substrate Specificity ,Bacterial Proteins ,RNA, Transfer ,Consensus sequence ,Escherichia coli ,Amino Acid Sequence ,Conserved Sequence ,tRNA Methyltransferases ,Multidisciplinary ,biology ,Escherichia coli Proteins ,TRNA Methyltransferase ,RNA ,Active site ,Biological Sciences ,TRNA Methyltransferases ,RNA, Bacterial ,Biochemistry ,Amino Acid Substitution ,Transfer RNA ,biology.protein ,Nucleic Acid Conformation ,Mutant Proteins ,T arm ,Sequence Alignment - Abstract
TrmA catalyzes S -adenosylmethionine (AdoMet)-dependent methylation of U54 in most tRNAs. We solved the structure of the Escherichia coli 5-methyluridine (m 5 U) 54 tRNA methyltransferase (MTase) TrmA in a covalent complex with a 19-nt T arm analog to 2.4-Å resolution. Mutation of the TrmA catalytic base Glu-358 to Gln arrested catalysis and allowed isolation of the covalent TrmA–RNA complex for crystallization. The protein–RNA interface includes 6 nt of the T loop and two proximal base pairs of the stem. U54 is flipped out of the loop into the active site. A58 occupies the space of the everted U54 and is part of a collinear base stack G53–A58–G57–C56–U55. The RNA fold is different from T loop conformations in unbound tRNA or T arm analogs, but nearly identical to the fold of the RNA loop bound at the active site of the m 5 U MTase RumA. In both enzymes, this consensus fold presents the target U and the following two bases to a conserved binding groove on the protein. Outside of this fold, the RumA and TrmA substrates have completely different structures and protein interfaces. Loop residues other than the target U54 make more than half of their hydrogen bonds to the protein via sugar-phosphate moieties, accounting, in part, for the broad consensus sequence for TrmA substrates.
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- 2008
13. Assessment of ternary model for the binding of agonists to neurohumoral receptors
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Michael J. Sole, James W. Wells, and Tom T. Lee
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chemistry.chemical_classification ,Neurotransmitter Agents ,Hill differential equation ,Binding Sites ,G protein ,Binding protein ,Receptors, Cell Surface ,Models, Biological ,Biochemistry ,Kinetics ,symbols.namesake ,chemistry ,GTP-Binding Proteins ,Dopamine receptor ,symbols ,Biophysics ,Muscarinic cholinergic ,Animals ,Nucleotide ,Receptor ,Ternary operation ,Mathematics ,Protein Binding - Abstract
A frequently cited variant of the "mobile receptor" hypothesis has been examined for its ability to describe the binding of agonists at neurohumoral receptors that operate via a guanylyl nucleotide binding protein. The model involves a reversible association between the receptor (R) and the G protein (G). Agonists (A) bind with different affinity to R and to the RG complex; similarly, G differentiates between R and the AR complex. Theoretical binding curves calculated according to the model have been analyzed in terms of the Hill equation and as a mixture of independent and noninteracting sites. The model is shown to be compatible in some respects with reported data on the binding of agonists to the beta-adrenergic receptor but not to the muscarinic cholinergic or D2 dopaminergic receptors. It is difficult to reconcile with the reported effects of guanylyl nucleotides, magnesium, and N-ethylmaleimide on the binding of agonists at any neurohumoral receptor.
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- 1986
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14. Author Correction: Generation of T-cell-receptor-negative CD8αβ-positive CAR T cells from T-cell-derived induced pluripotent stem cells.
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van der Stegen SJC, Lindenbergh PL, Petrovic RM, Xie H, Diop MP, Alexeeva V, Shi Y, Mansilla-Soto J, Hamieh M, Eyquem J, Cabriolu A, Wang X, Abujarour R, Lee T, Clarke R, Valamehr B, Themeli M, Riviere I, and Sadelain M
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- 2024
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15. Scrapping the two child benefit cap would immediately reduce poverty while investing in the future.
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Lee T
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Competing Interests: Competing interests: None declared.
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- 2024
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16. Genetic ablation of adhesion ligands mitigates rejection of allogeneic cellular immunotherapies.
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Hammer Q, Perica K, Mbofung RM, van Ooijen H, Martin KE, Momayyezi P, Varady E, Pan Y, Jelcic M, Groff B, Abujarour R, Krokeide SZ, Lee T, Williams A, Goodridge JP, Valamehr B, Önfelt B, Sadelain M, and Malmberg KJ
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- Animals, Mice, Ligands, Induced Pluripotent Stem Cells metabolism, Mice, Inbred C57BL, Graft Rejection immunology, Immunotherapy methods, CD58 Antigens metabolism, CD58 Antigens genetics, Humans, beta 2-Microglobulin genetics, beta 2-Microglobulin metabolism, Receptors, Chimeric Antigen metabolism, Receptors, Chimeric Antigen immunology, Intercellular Adhesion Molecule-1 metabolism, Killer Cells, Natural immunology
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Allogeneic cellular immunotherapies hold promise for broad clinical implementation but face limitations due to potential rejection of donor cells by the host immune system. Silencing of beta-2 microglobulin (B2M) expression is commonly employed to evade T cell-mediated rejection by the host, although the absence of B2M is expected to trigger missing-self responses by host natural killer (NK) cells. Here, we demonstrate that genetic deletion of the adhesion ligands CD54 and CD58 in B2M-deficient chimeric antigen receptor (CAR) T cells and multi-edited induced pluripotent stem cell (iPSC)-derived CAR NK cells reduces their susceptibility to rejection by host NK cells in vitro and in vivo. The absence of adhesion ligands limits rejection in a unidirectional manner in B2M-deficient and B2M-sufficient settings without affecting the antitumor functionality of the engineered donor cells. Thus, these data suggest that genetic ablation of adhesion ligands effectively alleviates rejection by host immune cells, facilitating the implementation of universal immunotherapy., Competing Interests: Declaration of interests K.-J.M. is a consultant and has research support from Fate Therapeutics. K.-J.M. has research support from Oncopeptides. K.-J.M. and Q.H. are consultants at Vycellix. All relationships have been approved by Oslo University Hospital, the University of Oslo, and the Karolinska Institute. R.M.M., E.V., Y.P., M.J., B.G., R.A., T.L., A.W., J.P.G., and B.V. are employees at Fate Therapeutics. Memorial Sloan Kettering has licensed IP (unrelated to this study) to Fate Therapeutics, and M.S. receives research support (for unrelated studies) from Fate Therapeutics., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2024
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17. Quantifying the cost savings and health impacts of improving colonoscopy quality: an economic evaluation.
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McCarthy S, Rutter MD, McMeekin P, Catlow J, Sharp L, Brookes M, Valori R, Bhardwaj-Gosling R, Lee T, McNally R, McCarthy A, and Gray J
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Objective: To estimate and quantify the cost implications and health impacts of improving the performance of English endoscopy services to the optimum quality as defined by postcolonoscopy colorectal cancer (PCCRC) rates., Design: A semi-Markov state-transition model was constructed, following the logical treatment pathway of individuals who could potentially undergo a diagnostic colonoscopy. The model consisted of three identical arms, each representing a high, middle or low-performing trust's endoscopy service, defined by PCCRC rates. A cohort of 40-year-old individuals was simulated in each arm of the model. The model's time horizon was when the cohort reached 90 years of age and the total costs and quality-adjusted life-years (QALYs) were calculated for all trusts. Scenario and sensitivity analyses were also conducted., Results: A 40-year-old individual gains 0.0006 QALYs and savings of £6.75 over the model lifetime by attending a high-performing trust compared with attending a middle-performing trust and gains 0.0012 QALYs and savings of £14.64 compared with attending a low-performing trust. For the population of England aged between 40 and 86, if all low and middle-performing trusts were improved to the level of a high-performing trust, QALY gains of 14 044 and cost savings of £249 311 295 are possible. Higher quality trusts dominated lower quality trusts; any improvement in the PCCRC rate was cost-effective., Conclusion: Improving the quality of endoscopy services would lead to QALY gains among the population, in addition to cost savings to the healthcare provider. If all middle and low-performing trusts were improved to the level of a high-performing trust, our results estimate that the English National Health Service would save approximately £5 million per year., Competing Interests: Competing interests: MDR reports paid leadership or fiduciary roles in other board, society, committee or advocacy group for UK National Endoscopy Database committee, UK Joint Advisory Group for GI Endoscopy and NHS England. LS reports research funding from Medtronic and 3D-Matrix. MB reports research funding from NIHR Health Technology Assessment, support for attending meeting and/or travel from Janssen Pharma and participation on a Data Safety Monitoring Board or Advisory Board for Norgine Pharma, Vifor Pharma and GE Healthcare., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2024
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18. Genetic ablation of adhesion ligands averts rejection of allogeneic immune cells.
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Hammer Q, Perica K, van Ooijen H, Mbofung R, Momayyezi P, Varady E, Martin KE, Pan Y, Jelcic M, Groff B, Abujarour R, Krokeide S, Lee T, Williams A, Goodridge JP, Valamehr B, Önfelt B, Sadelain M, and Malmberg KJ
- Abstract
Allogeneic cell therapies hold promise for broad clinical implementation, but face limitations due to potential rejection by the recipient immune system. Silencing of beta-2-microglobulin ( B2M ) expression is commonly employed to evade T cell-mediated rejection, although absence of B2M triggers missing-self responses by recipient natural killer (NK) cells. Here, we demonstrate that deletion of the adhesion ligands CD54 and CD58 on targets cells robustly dampens NK cell reactivity across all sub-populations. Genetic deletion of CD54 and CD58 in B2M -deficient allogeneic chimeric antigen receptor (CAR) T and multi-edited induced pluripotent stem cell (iPSC)-derived NK cells reduces their susceptibility to rejection by NK cells in vitro and in vivo without affecting their anti-tumor effector potential. Thus, these data suggest that genetic ablation of adhesion ligands effectively alleviates rejection of allogeneic immune cells for immunotherapy.
- Published
- 2023
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19. Atomic-scale origin of the low grain-boundary resistance in perovskite solid electrolyte Li 0.375 Sr 0.4375 Ta 0.75 Zr 0.25 O 3 .
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Lee T, Qi J, Gadre CA, Huyan H, Ko ST, Zuo Y, Du C, Li J, Aoki T, Wu R, Luo J, Ong SP, and Pan X
- Abstract
Oxide solid electrolytes (OSEs) have the potential to achieve improved safety and energy density for lithium-ion batteries, but their high grain-boundary (GB) resistance generally is a bottleneck. In the well-studied perovskite oxide solid electrolyte, Li
3x La2/3-x TiO3 (LLTO), the ionic conductivity of grain boundaries is about three orders of magnitude lower than that of the bulk. In contrast, the related Li0.375 Sr0.4375 Ta0.75 Zr0.25 O3 (LSTZ0.75) perovskite exhibits low grain boundary resistance for reasons yet unknown. Here, we use aberration-corrected scanning transmission electron microscopy and spectroscopy, along with an active learning moment tensor potential, to reveal the atomic scale structure and composition of LSTZ0.75 grain boundaries. Vibrational electron energy loss spectroscopy is applied for the first time to reveal atomically resolved vibrations at grain boundaries of LSTZ0.75 and to characterize the otherwise unmeasurable Li distribution therein. We find that Li depletion, which is a major reason for the low grain boundary ionic conductivity of LLTO, is absent for the grain boundaries of LSTZ0.75. Instead, the low grain boundary resistivity of LSTZ0.75 is attributed to the formation of a nanoscale defective cubic perovskite interfacial structure that contained abundant vacancies. Our study provides new insights into the atomic scale mechanisms of low grain boundary resistivity., (© 2023. The Author(s).)- Published
- 2023
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20. Generation of T-cell-receptor-negative CD8αβ-positive CAR T cells from T-cell-derived induced pluripotent stem cells.
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van der Stegen SJC, Lindenbergh PL, Petrovic RM, Xie H, Diop MP, Alexeeva V, Shi Y, Mansilla-Soto J, Hamieh M, Eyquem J, Cabriolu A, Wang X, Abujarour R, Lee T, Clarke R, Valamehr B, Themeli M, Riviere I, and Sadelain M
- Subjects
- Mice, Animals, Humans, T-Lymphocytes, Receptors, Antigen, T-Cell, CD8 Antigens metabolism, Induced Pluripotent Stem Cells metabolism, Receptors, Chimeric Antigen metabolism
- Abstract
The production of autologous T cells expressing a chimaeric antigen receptor (CAR) is time-consuming, costly and occasionally unsuccessful. T-cell-derived induced pluripotent stem cells (TiPS) are a promising source for the generation of 'off-the-shelf' CAR T cells, but the in vitro differentiation of TiPS often yields T cells with suboptimal features. Here we show that the premature expression of the T-cell receptor (TCR) or a constitutively expressed CAR in TiPS promotes the acquisition of an innate phenotype, which can be averted by disabling the TCR and relying on the CAR to drive differentiation. Delaying CAR expression and calibrating its signalling strength in TiPS enabled the generation of human TCR
- CD8αβ+ CAR T cells that perform similarly to CD8αβ+ CAR T cells from peripheral blood, achieving effective tumour control on systemic administration in a mouse model of leukaemia and without causing graft-versus-host disease. Driving T-cell maturation in TiPS in the absence of a TCR by taking advantage of a CAR may facilitate the large-scale development of potent allogeneic CD8αβ+ T cells for a broad range of immunotherapies., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2022
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21. Detection of Microsatellite Instability in Colonoscopic Biopsies and Postal Urine Samples from Lynch Syndrome Cancer Patients Using a Multiplex PCR Assay.
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Phelps R, Gallon R, Hayes C, Glover E, Gibson P, Edidi I, Lee T, Mills S, Shaw A, Heer R, Ralte A, McAnulty C, Santibanez-Koref M, Burn J, and Jackson MS
- Abstract
Identification of mismatch repair (MMR)-deficient colorectal cancers (CRCs) is recommended for Lynch syndrome (LS) screening, and supports targeting of immune checkpoint inhibitors. Microsatellite instability (MSI) analysis is commonly used to test for MMR deficiency. Testing biopsies prior to tumour resection can inform surgical and therapeutic decisions, but can be limited by DNA quantity. MSI analysis of voided urine could also provide much needed surveillance for genitourinary tract cancers in LS. Here, we reconfigure an existing molecular inversion probe-based MSI and BRAF c.1799T > A assay to a multiplex PCR (mPCR) format, and demonstrate that it can sample >140 unique molecules per marker from <1 ng of DNA and classify CRCs with 96−100% sensitivity and specificity. We also show that it can detect increased MSI within individual and composite CRC biopsies from LS patients, and within preoperative urine cell free DNA (cfDNA) from two LS patients, one with an upper tract urothelial cancer, the other an undiagnosed endometrial cancer. Approximately 60−70% of the urine cfDNAs were tumour-derived. Our results suggest that mPCR sequence-based analysis of MSI and mutation hotspots in CRC biopsies could facilitate presurgery decision making, and could enable postal-based screening for urinary tract and endometrial tumours in LS patients.
- Published
- 2022
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22. Use of Capillary Aerosol Generator in Continuous Production of Controlled Aerosol for Non-Clinical Studies.
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Goedertier D, Weber SS, Lucci F, Lee T, Tan WT, Radtke F, Krishnan S, Vanscheeuwijck P, Kuczaj AK, and Hoeng J
- Subjects
- Aerosols, Particle Size, Reproducibility of Results, Veins, Electronic Nicotine Delivery Systems
- Abstract
The capillary aerosol generator (CAG) is operated with the principal of thermal liquid evaporation through heating of e-liquid in the initial phase, followed by nucleation and condensation regulated through a mixture of airflow to generate aerosols, such as in an electronic cigarette (EC). The CAG is particularly useful in generating aerosols of large volumes in a continuous manner, for instances such as in vivo inhalation toxicology studies, where usage of ECs is not feasible. The thermal effects of generating aerosol from the CAG are similar in terms of temperature applied in an EC, thus allowing investigators to assess the vapors of e-liquids at scale and reproducibility. As the operation of the CAG allows users to control critical parameters such as the flow rate of e-liquid, heating temperatures and dilution air flows, it allows investigators to test various e-liquid formulations in a well-controlled device. Properties, such as aerosol particle size, are demonstrated to be regulated with the air flow rate with respect to the e-liquid flow and e-liquid composition. The CAG, however, is limited in assessing common EC-related issues, such as overheating of its elements. We seek to demonstrate that the CAG can generate aerosol that is reproducible and continuous, by assessing the chemical and physical aerosol characteristics with a chosen e-liquid formulation. The protocol describes the operating parameters of liquid flow rate, dilution air-flow rates and operating procedures needing to optimize the aerosol concentration and particle size required for an in vivo toxicology study. Presenting the representative results from the protocol and discussing the challenges and applications of working with a CAG, we demonstrate that CAG can be used in a reproducible fashion. The technology and protocol, that has been developed from prior work, serve as a foundation for future innovations for laboratory-controlled aerosol generation investigations.
- Published
- 2022
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23. Anti-NKG2C/IL-15/anti-CD33 killer engager directs primary and iPSC-derived NKG2C + NK cells to target myeloid leukemia.
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Chiu E, Felices M, Cichocki F, Davis Z, Wang H, Tuninga K, Vallera DA, Lee T, Bjordahl R, Malmberg KJ, Valamehr B, and Miller JS
- Subjects
- Cytomegalovirus, Humans, Interleukin-15, Killer Cells, Natural, Induced Pluripotent Stem Cells, Leukemia, Myeloid, Acute genetics, Leukemia, Myeloid, Acute therapy
- Abstract
Natural killer (NK) cells mediate the cytolysis of transformed cells and are currently used as an adoptive cellular therapy to treat cancer. Infection with human cytomegalovirus has been shown to expand a subset of "adaptive" NK cells expressing the activation receptor NKG2C that have preferred functional attributes distinct from conventional NK cells. Because NKG2C delivers a strong activating signal to NK cells, we hypothesized that NKG2C could specifically trigger NK-cell-mediated antitumor responses. To elicit a tumor-directed response from NKG2C
+ NK cells, we created an anti-NKG2C/IL-15/anti-CD33 killer engager called NKG2C-KE that directs NKG2C+ cells to target CD33+ cells and tumor-associated antigen expressed by acute myelogenous leukemia cells. The NKG2C-KE induced specific degranulation, interferon-γ production, and proliferation of NKG2C-expressing NK cells from patients who reactivated cytomegalovirus after allogeneic transplantation. The NKG2C-KE was also tested in a more homogeneous system using induced pluripotent stem cell (iPSC)-derived NK (iNK) cells that have been engineered to express NKG2C at high levels. The NKG2C-KE triggered iNK-cell-mediated cytotoxicity against CD33+ cells and primary AML blasts. The NKG2C-KE-specific interaction with adaptive NK and NKG2C+ iNK cells represents a new immunotherapeutic paradigm that uniquely engages highly active NK cells to induce cytotoxicity against AML through redirected targeting., (Copyright © 2021 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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24. Decision making in the management of adults with malignant colorectal polyps: An exploration of the experiences of patients and clinicians.
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Westwood C, Lee T, McSherry R, Bettany-Saltikov J, and Catlow J
- Subjects
- Adult, Decision Making, England, Humans, Qualitative Research, Colonic Polyps surgery
- Abstract
Aim: A diagnosis of colorectal polyp cancer presents a treatment dilemma. The decision between segmental resection versus endoscopic surveillance is difficult due to a lack of good quality clinical evidence for either option. The aim of this study was to understand the decision making experiences of both clinicians and patients when faced with such a diagnosis., Methods: Qualitative, semi-structured interviews were undertaken with 10 clinicians involved in the care of patients diagnosed with polyp cancer and five patients who had experience of a diagnosis of polyp cancer. All clinicians and patients were from four hospital trusts across the north of England. Interviews were audio-recorded, transcribed verbatim and analysed using the principles of interpretative phenomenological analysis., Results: Analysis of the interview transcripts evidenced that clinicians and patients were supportive of a shared approach to treatment decision making in the context of a diagnosis of colorectal polyp cancer. Uncertainty, influences and information were among the themes identified to be preventing this happening at present. This study identified themes which were common to both groups. These were complexity of the risk information, lack of patient information resources, and system factors and time., Conclusion: This research study has evidenced several factors such as uncertainty, complexity of risk information and influences on decisions which are preventing patients being involved in treatment decisions following a diagnosis of colorectal polyp cancer. Recommendations for improvements in practice, including a framework to assist treatment decision making in the future, are highlighted., (© 2021 The Association of Coloproctology of Great Britain and Ireland.)
- Published
- 2021
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25. A 6-month inhalation toxicology study in Apoe -/- mice demonstrates substantially lower effects of e-vapor aerosol compared with cigarette smoke in the respiratory tract.
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Wong ET, Szostak J, Titz B, Lee T, Wong SK, Lavrynenko O, Merg C, Corciulo M, Simicevic J, Auberson M, Peric D, Dulize R, Bornand D, Loh GJ, Lee KM, Zhang J, Miller JH 4th, Schlage WK, Guedj E, Schneider T, Phillips B, Leroy P, Choukrallah MA, Sierro N, Buettner A, Xiang Y, Kuczaj A, Ivanov NV, Luettich K, Vanscheeuwijck P, Peitsch MC, and Hoeng J
- Subjects
- Aerosols, Animals, Apolipoproteins E metabolism, Female, Inhalation Exposure, Lung, Mice, Nicotine, Respiratory Function Tests, Smoking, Tobacco Products, Transcriptome, Electronic Nicotine Delivery Systems, Smoke
- Abstract
Cigarette smoking is the major cause of chronic obstructive pulmonary disease. Considerable attention has been paid to the reduced harm potential of nicotine-containing inhalable products such as electronic cigarettes (e-cigarettes). We investigated the effects of mainstream cigarette smoke (CS) and e-vapor aerosols (containing nicotine and flavor) generated by a capillary aerosol generator on emphysematous changes, lung function, and molecular alterations in the respiratory system of female Apoe
-/- mice. Mice were exposed daily (3 h/day, 5 days/week) for 6 months to aerosols from three different e-vapor formulations-(1) carrier (propylene glycol and vegetable glycerol), (2) base (carrier and nicotine), or (3) test (base and flavor)-or to CS from 3R4F reference cigarettes. The CS and base/test aerosol concentrations were matched at 35 µg nicotine/L. CS exposure, but not e-vapor exposure, led to impairment of lung function (pressure-volume loop area, A and K parameters, quasi-static elastance and compliance) and caused marked lung inflammation and emphysematous changes, which were confirmed histopathologically and morphometrically. CS exposure caused lung transcriptome (activation of oxidative stress and inflammatory responses), lipidome, and proteome dysregulation and changes in DNA methylation; in contrast, these effects were substantially reduced in response to the e-vapor aerosol exposure. Compared with sham, aerosol exposure (carrier, base, and test) caused a slight impact on lung inflammation and epithelia irritation. Our results demonstrated that, in comparison with CS, e-vapor aerosols induced substantially lower biological and pathological changes in the respiratory tract associated with chronic inflammation and emphysema.- Published
- 2021
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26. The National Endoscopy Database (NED) Automated Performance Reports to Improve Quality Outcomes Trial (APRIQOT) randomized controlled trial design.
- Author
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Catlow J, Sharp L, Kasim A, Lu L, Brookes M, Lee T, McCarthy S, Gray J, Sniehotta F, Deane J, and Rutter M
- Abstract
Background and study aims Colonoscopists with low polyp detection have higher post colonoscopy colorectal cancer incidence and mortality rates. The United Kingdom's National Endoscopy Database (NED) automatically captures patient level data in real time and provides endoscopy key performance indicators (KPI) at a national, endoscopy center, and individual level. Using an electronic behavior change intervention, the primary objective of this study is to assess if automated feedback of endoscopist and endoscopy center-level optimal procedure-adjusted detection KPI (opadKPI) improves polyp detection performance. Methods This multicenter, prospective, cluster-randomized controlled trial is randomizing NHS endoscopy centres to either intervention or control. The intervention is targeted at independent colonoscopists and each center's endoscopy lead. The intervention reports are evidence-based from endoscopist qualitative interviews and informed by psychological theories of behavior. NED automatically creates monthly reports providing an opadKPI, using mean number of polyps, and an action plan. The primary outcome is opadKPI comparing endoscopists in intervention and control centers at 9 months. Secondary outcomes include other KPI and proximal detection measures at 9 and 12 months. A nested histological validation study will correlate opadKPI to adenoma detection rate at the center level. A cost-effectiveness and budget impact analysis will be undertaken. Conclusion If the intervention is efficacious and cost-effective, we will showcase the potential of this learning health system, which can be implemented at local and national levels to improve colonoscopy quality, and demonstrate that an automated system that collects, analyses, and disseminates real-time clinical data can deliver evidence- and theory-informed feedback., Competing Interests: Competing interests The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)
- Published
- 2020
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27. Evaluation of toxicity of aerosols from flavored e-liquids in Sprague-Dawley rats in a 90-day OECD inhalation study, complemented by transcriptomics analysis.
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Ho J, Sciuscio D, Kogel U, Titz B, Leroy P, Vuillaume G, Talikka M, Martin E, Pospisil P, Lebrun S, Xia W, Lee T, Chng YX, Phillips BW, Veljkovic E, Guedj E, Xiang Y, Ivanov NV, Peitsch MC, Hoeng J, and Vanscheeuwijck P
- Subjects
- Animals, Biomarkers blood, Consumer Product Safety, Female, Inhalation Exposure, Liver metabolism, Liver pathology, Male, Rats, Sprague-Dawley, Respiratory System immunology, Respiratory System metabolism, Respiratory System pathology, Risk Assessment, Time Factors, Toxicity Tests, E-Cigarette Vapor toxicity, Electronic Nicotine Delivery Systems, Flavoring Agents toxicity, Gene Expression Profiling, Liver drug effects, Respiratory System drug effects, Transcriptome drug effects, Vaping adverse effects
- Abstract
The use of flavoring substances is an important element in the development of reduced-risk products for adult smokers to increase product acceptance and encourage switching from cigarettes. In a first step towards characterizing the sub-chronic inhalation toxicity of neat flavoring substances, a study was conducted using a mixture of the substances in a base solution of e-liquid, where the standard toxicological endpoints of the nebulized aerosols were supplemented with transcriptomics analysis. The flavor mixture was produced by grouping 178 flavors into 26 distinct chemical groups based on structural similarities and potential metabolic and biological effects. Flavoring substances predicted to show the highest toxicological effect from each group were selected as the flavor group representatives (FGR). Following Organization for Economic Cooperation and Development Testing Guideline 413, rats were exposed to three concentrations of the FGR mixture in an e-liquid composed of nicotine (23 µg/L), propylene glycol (1520 µg/L), and vegetable glycerin (1890 µg/L), while non-flavored and no-nicotine mixtures were included as references to identify potential additive or synergistic effects between nicotine and the flavoring substances. The results indicated that the inhalation of an e-liquid containing the mixture of FGRs caused very minimal local and systemic toxic effects. In particular, there were no remarkable clinical (in-life) observations in flavored e-liquid-exposed rats. The biological effects related to exposure to the mixture of neat FGRs were limited and mainly nicotine-mediated, including changes in hematological and blood chemistry parameters and organ weight. These results indicate no significant additive biological changes following inhalation exposure to the nebulized FGR mixture above the nicotine effects measured in this sub-chronic inhalation study. In a subsequent study, e-liquids with FGR mixtures will be aerosolized by thermal treatment and assessed for toxicity.
- Published
- 2020
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28. Characterization of Antineovascularization Activity and Ocular Pharmacokinetics of Phosphoinositide 3-Kinase/Mammalian Target of Rapamycin Inhibitor GNE-947.
- Author
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Liu X, Liang X, LeCouter J, Ubhayakar S, Chen J, Cheng J, Lee T, Lubach J, Nonomiya J, Shahidi-Latham S, Quiason C, Solon E, Wright M, Hop CECA, and Heffron TP
- Subjects
- Angiogenesis Inhibitors chemistry, Angiogenesis Inhibitors therapeutic use, Animals, Choroidal Neovascularization etiology, Choroidal Neovascularization pathology, Disease Models, Animal, Half-Life, Human Umbilical Vein Endothelial Cells, Humans, Injections, Intravenous, Intravitreal Injections, Male, Models, Biological, Ophthalmic Solutions pharmacology, Ophthalmic Solutions therapeutic use, Phosphoinositide-3 Kinase Inhibitors chemistry, Phosphoinositide-3 Kinase Inhibitors therapeutic use, Rabbits, Rats, Solubility, TOR Serine-Threonine Kinases metabolism, Tissue Distribution, Angiogenesis Inhibitors pharmacology, Choroidal Neovascularization drug therapy, Phosphoinositide-3 Kinase Inhibitors pharmacology, TOR Serine-Threonine Kinases antagonists & inhibitors
- Abstract
The objectives of the present study were to characterize GNE-947 for its phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitory activities, in vitro anti-cell migration activity in human umbilical vein endothelial cells (HUVECs), in vivo antineovascularization activity in laser-induced rat choroidal neovascular (CNV) eyes, pharmacokinetics in rabbit plasma and eyes, and ocular distribution using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) and autoradioluminography. Its PI3K and mTOR K
i were 0.0005 and 0.045 µM, respectively, and its HUVEC IC50 was 0.093 µM. GNE-947 prevented neovascularization in the rat CNV model at 50 or 100 µg per eye with repeat dosing. After a single intravenous injection at 2.5 and 500 μg/kg in rabbits, its plasma terminal half-lives ( t1/2 ) were 9.11 and 9.59 hours, respectively. After a single intravitreal injection of a solution at 2.5 μg per eye in rabbits, its apparent t1/2 values were 14.4, 16.3, and 23.2 hours in the plasma, vitreous humor, and aqueous humor, respectively. After a single intravitreal injection of a suspension at 33.5, 100, 200 μg per eye in rabbits, the t1/2 were 29, 74, and 219 days in the plasma and 46, 143, and 191 days in the eyes, respectively. MALDI-IMS and autoradioluminography images show that GNE-947 did not homogenously distribute in the vitreous humor and aggregated at the injection sites after injection of the suspension, which was responsible for the long t1/2 of the suspension because of the slow dissolution process. This hypothesis was supported by pharmacokinetic modeling analyses. In conclusion, the PI3K/mTOR inhibitor GNE-947 prevented neovascularization in a rat CNV model, with t1/2 up to approximately 6 months after a single intravitreal injection of the suspension in rabbit eyes. SIGNIFICANCE STATEMENT: GNE-947 is a potent phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor and exhibits anti-choroidal neovascular activity in rat eyes. The duration of GNE-947 in the rabbit eyes after intravitreal injection in a solution is short, with a half-life ( t1/2 ) of less than a day. However, the duration after intravitreal dose of a suspension is long, with t1/2 up to 6 months due to low solubility and slow dissolution. These results indicate that intravitreal injection of a suspension for low-solubility drugs can be used to achieve long-term drug exposure., (Copyright © 2020 by The American Society for Pharmacology and Experimental Therapeutics.)- Published
- 2020
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29. A 6-month systems toxicology inhalation study in ApoE -/- mice demonstrates reduced cardiovascular effects of E-vapor aerosols compared with cigarette smoke.
- Author
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Szostak J, Wong ET, Titz B, Lee T, Wong SK, Low T, Lee KM, Zhang J, Kumar A, Schlage WK, Guedj E, Phillips B, Leroy P, Buettner A, Xiang Y, Martin F, Sewer A, Kuczaj A, Ivanov NV, Luettich K, Vanscheeuwijck P, Peitsch MC, and Hoeng J
- Subjects
- Animals, Apolipoproteins E genetics, Atherosclerosis metabolism, Atherosclerosis pathology, Cardiovascular Diseases metabolism, Cardiovascular Diseases pathology, Disease Progression, Female, Inhalation Exposure, Mice, Mice, Knockout, Myocardium metabolism, Myocardium pathology, Oxidative Stress drug effects, Aerosols toxicity, Atherosclerosis etiology, Cardiovascular Diseases etiology, E-Cigarette Vapor toxicity, Heart drug effects, Smoke adverse effects
- Abstract
Smoking cigarettes is harmful to the cardiovascular system. Considerable attention has been paid to the reduced harm potential of alternative nicotine-containing inhalable products such as e-cigarettes. We investigated the effects of E-vapor aerosols or cigarette smoke (CS) on atherosclerosis progression, cardiovascular function, and molecular changes in the heart and aorta of female apolipoprotein E-deficient (ApoE
-/- ) mice. The mice were exposed to aerosols from three different E-vapor formulations: 1 ) carrier (propylene glycol and vegetable glycerol), 2 ) base (carrier and nicotine), or 3 ) test (base and flavor) or to CS from 3R4F reference cigarettes for up to 6 mo. Concentrations of CS and base or test aerosols were matched at 35 µg nicotine/L. Exposure to CS, compared with sham-exposed fresh air controls, accelerated atherosclerotic plaque formation, whereas no such effect was seen for any of the three E-vapor aerosols. Molecular changes indicated disease mechanisms related to oxidative stress and inflammation in general, plus changes in calcium regulation, and altered cytoskeletal organization and microtubule dynamics in the left ventricle. While ejection fraction, fractional shortening, cardiac output, and isovolumic contraction time remained unchanged following E-vapor aerosols exposure, the nicotine-containing base and test aerosols caused an increase in isovolumic relaxation time similar to CS. A nicotine-related increase in pulse wave velocity and arterial stiffness was also observed, but it was significantly lower for base and test aerosols than for CS. These results demonstrate that in comparison with CS, E-vapor aerosols induce substantially lower biological responses associated with smoking-related cardiovascular diseases. NEW & NOTEWORTHY Analysis of key urinary oxidative stress markers and proinflammatory cytokines showed an absence of oxidative stress and inflammation in the animals exposed to E-vapor aerosols. Conversely, animals exposed to conventional cigarette smoke had high urinary levels of these markers. When compared with conventional cigarette smoke, E-vapor aerosols induced smaller atherosclerotic plaque surface area and volume. Systolic and diastolic cardiac function, as well as endothelial function, were further significantly less affected by electronic cigarette aerosols than conventional cigarette smoke. Molecular analysis demonstrated that E-vapor aerosols induce significantly smaller transcriptomic dysregulation in the heart and aorta compared with conventional cigarette smoke.- Published
- 2020
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30. Defects in the Neuroendocrine Axis Contribute to Global Development Delay in a Drosophila Model of NGLY1 Deficiency.
- Author
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Rodriguez TP, Mast JD, Hartl T, Lee T, Sand P, and Perlstein EO
- Subjects
- Alleles, Animals, Animals, Genetically Modified, Congenital Disorders of Glycosylation metabolism, Disease Models, Animal, Drosophila metabolism, Female, Genes, Lethal, Genotype, Humans, Larva, Mutation, Neurodevelopmental Disorders metabolism, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase genetics, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase metabolism, Phenotype, Proteasome Endopeptidase Complex genetics, Proteasome Endopeptidase Complex metabolism, Proteasome Inhibitors pharmacology, Congenital Disorders of Glycosylation genetics, Drosophila genetics, Genetic Association Studies, Neurodevelopmental Disorders genetics, Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase deficiency
- Abstract
N-glycanase 1 (NGLY1) Deficiency is a rare monogenic multi-system disorder first described in 2014. NGLY1 is evolutionarily conserved in model organisms. Here we conducted a natural history study and chemical-modifier screen on the Drosophila melanogaster NGLY1 homolog, Pngl We generated a new fly model of NGLY1 Deficiency, engineered with a nonsense mutation in Pngl at codon 420 that results in a truncation of the C-terminal carbohydrate-binding PAW domain. Homozygous mutant animals exhibit global development delay, pupal lethality and small body size as adults. We developed a 96-well-plate, image-based, quantitative assay of Drosophila larval size for use in a screen of the 2,650-member Microsource Spectrum compound library of FDA approved drugs, bioactive tool compounds, and natural products. We found that the cholesterol-derived ecdysteroid molting hormone 20-hydroxyecdysone (20E) partially rescued the global developmental delay in mutant homozygotes. Targeted expression of a human NGLY1 transgene to tissues involved in ecdysteroidogenesis, e.g. , prothoracic gland, also partially rescues global developmental delay in mutant homozygotes. Finally, the proteasome inhibitor bortezomib is a potent enhancer of global developmental delay in our fly model, evidence of a defective proteasome "bounce-back" response that is also observed in nematode and cellular models of NGLY1 Deficiency. Together, these results demonstrate the therapeutic relevance of a new fly model of NGLY1 Deficiency for drug discovery and gene modifier screens., (Copyright © 2018 Rodriguez et al.)
- Published
- 2018
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31. A 90-day OECD TG 413 rat inhalation study with systems toxicology endpoints demonstrates reduced exposure effects of the aerosol from the carbon heated tobacco product version 1.2 (CHTP1.2) compared with cigarette smoke. I. Inhalation exposure, clinical pathology and histopathology.
- Author
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Phillips BW, Schlage WK, Titz B, Kogel U, Sciuscio D, Martin F, Leroy P, Vuillaume G, Krishnan S, Lee T, Veljkovic E, Elamin A, Merg C, Ivanov NV, Peitsch MC, Hoeng J, and Vanscheeuwijck P
- Subjects
- Animals, Biomarkers blood, Biomarkers urine, Body Weight drug effects, Bronchoalveolar Lavage Fluid, Clinical Chemistry Tests, Feeding Behavior drug effects, Female, Hematologic Tests, Hot Temperature, Male, Nasal Mucosa drug effects, Nasal Mucosa pathology, Organ Size drug effects, Rats, Sprague-Dawley, Respiratory System pathology, Respiratory System physiopathology, Toxicity Tests, Aerosols toxicity, Carbon, Inhalation Exposure, Respiratory System drug effects, Smoke adverse effects
- Abstract
Within the framework of a systems toxicology approach, the inhalation toxicity of aerosol from a novel tobacco-heating potentially modified risk tobacco product (MRTP), the carbon-heated tobacco product (CHTP) 1.2, was characterized and compared with that of mainstream smoke (CS) from the 3R4F reference cigarette in a 90-day nose-only rat inhalation study in general accordance with OECD TG 413. CHTP1.2 is a heat-not-burn product using a carbon heat source to produce an aerosol that contains nicotine and tobacco flavor. At equal or twice the nicotine concentration in the test atmospheres, inhalation of CHTP1.2 aerosol led to a significantly lower exposure to harmful constituents and induced less respiratory tract irritation, systemic, and pathological effects compared with CS. Nasal epithelial changes were less pronounced in the CHTP1.2- than in the CS-exposed groups and reverted in the nicotine concentration-matched group after a recovery period. Lung inflammation was minimal in the CHTP1.2-treated groups compared with the moderate extent seen in the 3R4F groups. Many other toxicological endpoints evaluated did not show CHTP1.2 aerosol exposure-related effects, and no effects not seen for 3R4F were observed. These observations were consistent with findings from previous studies in which rats were exposed to MRTP aerosols containing similar nicotine concentrations., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2018
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32. Correction to Imprinted NanoVelcro Microchips for Isolation and Characterization of Circulating Fetal Trophoblasts: Toward Noninvasive Prenatal Diagnostics.
- Author
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Hou S, Chen JF, Song M, Zhu Y, Jan YJ, Chen SH, Weng TH, Ling DA, Chen SF, Ro T, Liang AJ, Lee T, Jin H, Li M, Liu L, Hsiao YS, Chen P, Yu HH, Tsai MS, Pisarska MD, Chen A, Chen LC, and Tseng HR
- Published
- 2017
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33. Imprinted NanoVelcro Microchips for Isolation and Characterization of Circulating Fetal Trophoblasts: Toward Noninvasive Prenatal Diagnostics.
- Author
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Hou S, Chen JF, Song M, Zhu Y, Jan YJ, Chen SH, Weng TH, Ling DA, Chen SF, Ro T, Liang AJ, Lee T, Jin H, Li M, Liu L, Hsiao YS, Chen P, Yu HH, Tsai MS, Pisarska MD, Chen A, Chen LC, and Tseng HR
- Subjects
- Adolescent, Adult, Female, Genetic Testing, Humans, Immunohistochemistry, Male, Trisomy genetics, Trophoblasts metabolism, Young Adult, Comparative Genomic Hybridization methods, DNA chemistry
- Abstract
Circulating fetal nucleated cells (CFNCs) in maternal blood offer an ideal source of fetal genomic DNA for noninvasive prenatal diagnostics (NIPD). We developed a class of nanoVelcro microchips to effectively enrich a subcategory of CFNCs, i.e., circulating trophoblasts (cTBs) from maternal blood, which can then be isolated with single-cell resolution by a laser capture microdissection (LCM) technique for downstream genetic testing. We first established a nanoimprinting fabrication process to prepare the LCM-compatible nanoVelcro substrates. Using an optimized cTB-capture condition and an immunocytochemistry protocol, we were able to identify and isolate single cTBs (Hoechst+/CK7+/HLA-G+/CD45-, 20 μm > sizes > 12 μm) on the imprinted nanoVelcro microchips. Three cTBs were polled to ensure reproducible whole genome amplification on the cTB-derived DNA, paving the way for cTB-based array comparative genomic hybridization (aCGH) and short tandem repeats analysis. Using maternal blood samples collected from expectant mothers carrying a single fetus, the cTB-derived aCGH data were able to detect fetal genders and chromosomal aberrations, which had been confirmed by standard clinical practice. Our results support the use of nanoVelcro microchips for cTB-based noninvasive prenatal genetic testing, which holds potential for further development toward future NIPD solution.
- Published
- 2017
- Full Text
- View/download PDF
34. Linear topology in amorphous metal oxide electrochromic networks obtained via low-temperature solution processing.
- Author
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Llordés A, Wang Y, Fernandez-Martinez A, Xiao P, Lee T, Poulain A, Zandi O, Saez Cabezas CA, Henkelman G, and Milliron DJ
- Abstract
Amorphous transition metal oxides are recognized as leading candidates for electrochromic window coatings that can dynamically modulate solar irradiation and improve building energy efficiency. However, their thin films are normally prepared by energy-intensive sputtering techniques or high-temperature solution methods, which increase manufacturing cost and complexity. Here, we report on a room-temperature solution process to fabricate electrochromic films of niobium oxide glass (NbO
x ) and 'nanocrystal-in-glass' composites (that is, tin-doped indium oxide (ITO) nanocrystals embedded in NbOx glass) via acid-catalysed condensation of polyniobate clusters. A combination of X-ray scattering and spectroscopic characterization with complementary simulations reveals that this strategy leads to a unique one-dimensional chain-like NbOx structure, which significantly enhances the electrochromic performance, compared to a typical three-dimensional NbOx network obtained from conventional high-temperature thermal processing. In addition, we show how self-assembled ITO-in-NbOx composite films can be successfully integrated into high-performance flexible electrochromic devices.- Published
- 2016
- Full Text
- View/download PDF
35. The Value of Pre- and Intraoperative Adjuncts on the Extent of Resection of Hemispheric Low-Grade Gliomas: A Retrospective Analysis.
- Author
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Incekara F, Olubiyi O, Ozdemir A, Lee T, Rigolo L, and Golby A
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Brain Neoplasms diagnostic imaging, Diffusion Tensor Imaging methods, Female, Glioma diagnostic imaging, Humans, Magnetic Resonance Imaging methods, Male, Middle Aged, Retrospective Studies, Treatment Outcome, Young Adult, Brain Neoplasms surgery, Craniotomy methods, Glioma surgery, Monitoring, Intraoperative methods, Neuronavigation methods, Neurosurgical Procedures methods
- Abstract
Background: To achieve maximal resection with minimal risk of postoperative neurologic morbidity, different neurosurgical adjuncts are being used during low-grade glioma (LGG) surgery., Objectives: To investigate the effect of pre- and intraoperative adjuncts on the extent of resection (EOR) of hemispheric LGGs., Methods: Medical records were reviewed to identify patients of any sex, ≥ 18 years of age, who underwent LGG surgery at X Hospital between January 2005 and July 2013. Patients were divided into eight subgroups based on the use of various combinations of a neuronavigation system alone (NN), functional MRI-diffusion tensor imaging (fMRI-DTI) guided neuronavigation (FD), intraoperative MRI (MR), and direct electrical stimulation (DES). Initial and residual tumors were measured, and mean EOR was compared between groups., Results: Of all 128 patients, gross total resection was achieved in 23.4%. Overall mean EOR was 81.3% ± 20.5%. Using DES in combination with fMRI-DTI (mean EOR: 86.7% ± 12.4%) on eloquent tumors improved mean EOR significantly after adjustment for potential confounders when compared with NN alone (mean EOR: 76.4% ± 25.5%; p = 0.001)., Conclusions: Using DES in combination with fMRI and DTI significantly improves EOR when LGGs are located in eloquent areas compared with craniotomies in which only NN was used., (Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2016
- Full Text
- View/download PDF
36. A comparison of isolated circulating tumor cells and tissue biopsies using whole-genome sequencing in prostate cancer.
- Author
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Jiang R, Lu YT, Ho H, Li B, Chen JF, Lin M, Li F, Wu K, Wu H, Lichterman J, Wan H, Lu CL, OuYang W, Ni M, Wang L, Li G, Lee T, Zhang X, Yang J, Rettig M, Chung LW, Yang H, Li KC, Hou Y, Tseng HR, Hou S, Xu X, Wang J, and Posadas EM
- Subjects
- Base Sequence, Biopsy, Cell Separation, Chromosomes, Human, DNA Mutational Analysis, Gene Expression Regulation, Neoplastic, Gene Rearrangement, Genetic Predisposition to Disease, Genome-Wide Association Study, Humans, Laser Capture Microdissection, Liver Neoplasms genetics, Liver Neoplasms secondary, Male, Molecular Sequence Data, Mutation, Nanotechnology, Neoplastic Cells, Circulating pathology, Oligonucleotide Array Sequence Analysis, Phenotype, Polymorphism, Single Nucleotide, Predictive Value of Tests, Prostatic Neoplasms blood, Prostatic Neoplasms pathology, Prostatic Neoplasms therapy, Time Factors, Biomarkers, Tumor genetics, Gene Expression Profiling methods, Genomics methods, Neoplastic Cells, Circulating chemistry, Prostatic Neoplasms genetics
- Abstract
Previous studies have demonstrated focal but limited molecular similarities between circulating tumor cells (CTCs) and biopsies using isolated genetic assays. We hypothesized that molecular similarity between CTCs and tissue exists at the single cell level when characterized by whole genome sequencing (WGS). By combining the NanoVelcro CTC Chip with laser capture microdissection (LCM), we developed a platform for single-CTC WGS. We performed this procedure on CTCs and tissue samples from a patient with advanced prostate cancer who had serial biopsies over the course of his clinical history. We achieved 30X depth and ≥ 95% coverage. Twenty-nine percent of the somatic single nucleotide variations (SSNVs) identified were founder mutations that were also identified in CTCs. In addition, 86% of the clonal mutations identified in CTCs could be traced back to either the primary or metastatic tumors. In this patient, we identified structural variations (SVs) including an intrachromosomal rearrangement in chr3 and an interchromosomal rearrangement between chr13 and chr15. These rearrangements were shared between tumor tissues and CTCs. At the same time, highly heterogeneous short structural variants were discovered in PTEN, RB1, and BRCA2 in all tumor and CTC samples. Using high-quality WGS on single-CTCs, we identified the shared genomic alterations between CTCs and tumor tissues. This approach yielded insight into the heterogeneity of the mutational landscape of SSNVs and SVs. It may be possible to use this approach to study heterogeneity and characterize the biological evolution of a cancer during the course of its natural history.
- Published
- 2015
- Full Text
- View/download PDF
37. Programming thermoresponsiveness of NanoVelcro substrates enables effective purification of circulating tumor cells in lung cancer patients.
- Author
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Ke Z, Lin M, Chen JF, Choi JS, Zhang Y, Fong A, Liang AJ, Chen SF, Li Q, Fang W, Zhang P, Garcia MA, Lee T, Song M, Lin HA, Zhao H, Luo SC, Hou S, Yu HH, and Tseng HR
- Subjects
- Adult, Aged, Antibodies chemistry, Antibodies immunology, Antigens, Neoplasm immunology, Base Sequence, Cell Adhesion Molecules immunology, Cell Line, Tumor, Epithelial Cell Adhesion Molecule, Female, Humans, Male, Middle Aged, Carcinoma, Non-Small-Cell Lung pathology, Cell Separation methods, Lung Neoplasms pathology, Nanostructures chemistry, Nanotechnology methods, Neoplastic Cells, Circulating pathology, Temperature
- Abstract
Unlike tumor biopsies that can be constrained by problems such as sampling bias, circulating tumor cells (CTCs) are regarded as the "liquid biopsy" of the tumor, providing convenient access to all disease sites, including primary tumor and fatal metastases. Although enumerating CTCs is of prognostic significance in solid tumors, it is conceivable that performing molecular and functional analyses on CTCs will reveal much significant insight into tumor biology to guide proper therapeutic intervention. We developed the Thermoresponsive NanoVelcro CTC purification system that can be digitally programmed to achieve an optimal performance for purifying CTCs from non-small cell lung cancer (NSCLC) patients. The performance of this unique CTC purification system was optimized by systematically modulating surface chemistry, flow rates, and heating/cooling cycles. By applying a physiologically endurable stimulation (i.e., temperature between 4 and 37 °C), the mild operational parameters allow minimum disruption to CTCs' viability and molecular integrity. Subsequently, we were able to successfully demonstrate culture expansion and mutational analysis of the CTCs purified by this CTC purification system. Most excitingly, we adopted the combined use of the Thermoresponsive NanoVelcro system with downstream mutational analysis to monitor the disease evolution of an index NSCLC patient, highlighting its translational value in managing NSCLC.
- Published
- 2015
- Full Text
- View/download PDF
38. High-purity prostate circulating tumor cell isolation by a polymer nanofiber-embedded microchip for whole exome sequencing.
- Author
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Zhao L, Lu YT, Li F, Wu K, Hou S, Yu J, Shen Q, Wu D, Song M, OuYang WH, Luo Z, Lee T, Fang X, Shao C, Xu X, Garcia MA, Chung LW, Rettig M, Tseng HR, and Posadas EM
- Subjects
- Cell Line, Tumor, Genomics, Humans, Lactic Acid chemistry, Male, Neoplastic Cells, Circulating metabolism, Polyglycolic Acid chemistry, Polylactic Acid-Polyglycolic Acid Copolymer, Prostatic Neoplasms genetics, Cell Separation methods, Exome genetics, Microchip Analytical Procedures methods, Nanofibers, Neoplastic Cells, Circulating pathology, Prostatic Neoplasms pathology, Sequence Analysis, DNA
- Abstract
Handpick single cancer cells: a modified NanoVelcro Chip is coupled with ArcturusXT laser capture microdissection (LCM) technology to enable the detection and isolation of single circulating tumor cells (CTCs) from patients with prostate cancer (PC). This new approach paves the way for conducting next-generation sequencing (NGS) on single CTCs., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
- Full Text
- View/download PDF
39. Specific capture and release of circulating tumor cells using aptamer-modified nanosubstrates.
- Author
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Shen Q, Xu L, Zhao L, Wu D, Fan Y, Zhou Y, Ouyang WH, Xu X, Zhang Z, Song M, Lee T, Garcia MA, Xiong B, Hou S, Tseng HR, and Fang X
- Subjects
- Cell Line, Tumor, Humans, Aptamers, Nucleotide chemistry, Aptamers, Nucleotide metabolism, Cell Separation methods, Nanostructures, Neoplastic Cells, Circulating pathology
- Published
- 2013
- Full Text
- View/download PDF
40. Capture and stimulated release of circulating tumor cells on polymer-grafted silicon nanostructures.
- Author
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Hou S, Zhao H, Zhao L, Shen Q, Wei KS, Suh DY, Nakao A, Garcia MA, Song M, Lee T, Xiong B, Luo SC, Tseng HR, and Yu HH
- Subjects
- Acrylic Resins chemistry, Antibodies chemistry, Antibodies immunology, Antigens, Neoplasm chemistry, Antigens, Neoplasm immunology, Biotin chemistry, Biotin metabolism, Cell Adhesion Molecules chemistry, Cell Adhesion Molecules immunology, Cell Line, Tumor, Cell Separation instrumentation, Epithelial Cell Adhesion Molecule, Humans, MCF-7 Cells, Polymers chemistry, Streptavidin chemistry, Streptavidin metabolism, Cell Separation methods, Nanowires chemistry, Neoplastic Cells, Circulating, Silicon chemistry
- Abstract
A platform for capture and release of circulating tumor cells is demonstrated by utilizing polymer grafted silicon nanowires. In this platform, integration of ligand-receptor recognition, nanostructure amplification, and thermal responsive polymers enables a highly efficient and selective capture of cancer cells. Subsequently, these captured cells are released upon a physical stimulation with outstanding cell viability., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
- Full Text
- View/download PDF
41. Polymer nanofiber-embedded microchips for detection, isolation, and molecular analysis of single circulating melanoma cells.
- Author
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Hou S, Zhao L, Shen Q, Yu J, Ng C, Kong X, Wu D, Song M, Shi X, Xu X, OuYang WH, He R, Zhao XZ, Lee T, Brunicardi FC, Garcia MA, Ribas A, Lo RS, and Tseng HR
- Subjects
- Cell Line, Tumor, Cell Separation, Erythrocytes cytology, Humans, Lactic Acid chemistry, Melanoma diagnosis, Melanoma metabolism, Microfluidic Analytical Techniques, Mutation, Neoplastic Cells, Circulating chemistry, Polyglycolic Acid chemistry, Polylactic Acid-Polyglycolic Acid Copolymer, Proto-Oncogene Proteins B-raf genetics, Proto-Oncogene Proteins B-raf metabolism, Single-Cell Analysis, Nanofibers chemistry, Neoplastic Cells, Circulating metabolism, Polymers chemistry
- Published
- 2013
- Full Text
- View/download PDF
42. Highly efficient capture of circulating tumor cells by using nanostructured silicon substrates with integrated chaotic micromixers.
- Author
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Wang S, Liu K, Liu J, Yu ZT, Xu X, Zhao L, Lee T, Lee EK, Reiss J, Lee YK, Chung LW, Huang J, Rettig M, Seligson D, Duraiswamy KN, Shen CK, and Tseng HR
- Subjects
- Breast Neoplasms blood, Breast Neoplasms pathology, Equipment Design, Female, Humans, Male, Microfluidics methods, Molecular Imaging, Neoplastic Cells, Circulating pathology, Prostatic Neoplasms blood, Prostatic Neoplasms pathology, Surface Properties, Breast Neoplasms chemistry, Complex Mixtures chemistry, Microfluidics instrumentation, Nanostructures chemistry, Neoplastic Cells, Circulating chemistry, Prostatic Neoplasms chemistry, Silicon chemistry
- Published
- 2011
- Full Text
- View/download PDF
43. Combined hypertension and orthostatic hypotension in older patients: a treatment dilemma for clinicians.
- Author
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Lee T, Donegan C, and Moore A
- Subjects
- Aged, Humans, Hypertension complications, Hypertension therapy, Hypotension, Orthostatic complications, Hypotension, Orthostatic therapy
- Abstract
The combination of hypertension and orthostatic hypotension in older individuals is becoming increasingly recognized. Managing this combination of disorders presents a treatment dilemma -- how to lower blood pressure to provide cardiovascular risk protection without predisposing to syncope. At present, there is no specific evidence base available with regard to managing such patients. Some antihypertensive drug classes (e.g., alpha-blockers) appear more problematic in this regard than others. In the absence of controlled-trial evidence, use of antihypertensives with a more gradual onset of effect commenced at lower doses and use of lower-limb compression hosiery appears to be a reasonable approach. Abdominal compression devices and elevating the head of the bed may also help to combat orthostatic hypotenstion in older patients with hypertension and warrant future research.
- Published
- 2005
- Full Text
- View/download PDF
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