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https://www.readbyqxmd.com/read/29036186/the-mgmt-promoter-single-nucleotide-polymorphism-rs1625649-had-prognostic-impact-on-patients-with-mgmt-methylated-glioblastoma
#1
Chih-Yi Hsu, Hsiang-Ling Ho, Shih-Chieh Lin, Tiffany Dai-Hwa Ho, Donald Ming-Tak Ho
Promoter methylation is the most significant mechanism to regulate O6-methylguanine-DNA-methyltransferase (MGMT) expression. Single-nucleotide polymorphisms (SNPs) in the MGMT promoter region may also play a role. The aim of this study was to evaluate the clinical significance of SNPs in the MGMT promoter region of glioblastoma. Genomic DNAs from 118 glioblastomas were collected for polymerase chain reaction (PCR) amplification. Sanger sequencing was used to sequence the MGMT promoter region to detect SNPs...
2017: PloS One
https://www.readbyqxmd.com/read/29034863/the-o-antigen-structure-of-bacterium-comamonas-aquatica-cjg
#2
Xiqian Wang, Anna N Kondakova, Yutong Zhu, Yuriy A Knirel, Aidong Han
Genus Comamonas is a group of bacteria that are able to degrade a variety of environmental waste. Comamonas aquatica CJG (C. aquatica) in this genus is able to absorb low-density lipoprotein but not high-density lipoprotein of human serum. Using (1)H and (13)C NMR spectroscopy, we found that the O-polysaccharide (O-antigen) of this bacterium is comprised of a disaccharide repeat (O-unit) of d-glucose and 2-O-acetyl-l-rhamnose, which is shared by Serratia marcescens O6. The O-antigen gene cluster of C. aquatica, which is located between coaX and tnp4 genes, contains rhamnose synthesis genes, glycosyl and acetyl transferase genes, and ATP-binding cassette transporter genes, and therefore is consistent with the O-antigen structure determined here...
October 16, 2017: Microbiology
https://www.readbyqxmd.com/read/29033608/is-the-prognostic-significance-of-o6-methylguanine-dna-methyltransferase-promoter-methylation-equally-important-in-glioblastomas-of-patients-from-different-continents-a-systematic-review-with-meta-analysis
#3
REVIEW
Wei Meng, Yangyang Jiang, Jie Ma
BACKGROUND: O6-methylguanine-DNA methyltransferase (MGMT) is an independent predictor of therapeutic response and potential prognosis in patients with glioblastoma multiforme (GBM). However, its significance of clinical prognosis in different continents still needs to be explored. PATIENTS AND METHODS: To explore the effects of MGMT promoter methylation on both progression-free survival (PFS) and overall survival (OS) among GBM patients from different continents, a systematic review of published studies was conducted...
2017: Cancer Management and Research
https://www.readbyqxmd.com/read/29031038/isocitrate-dehydrogenase-mutations-are-better-prognostic-marker-than-o6-methylguanine-dna-methyltransferase-promoter-methylation-in-glioblastomas-a-retrospective-single-centre-molecular-genetics-study-of-gliomas
#4
M Houdova Megova, J Drábek, Z Dwight, R Trojanec, V Koudeláková, J Vrbková, O Kalita, S Mlcochova, M Rabcanova, M Hajdúch
BACKGROUND: Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) are a promising prognostic biomarker of gliomas. The purpose of our study was to examine the clinical prognostic properties of IDH1/2 mutations in a glioma patient cohort from the Czech Republic using an improved platform for simple and reliable IDH genotyping. MATERIAL AND METHODS: We retrospectively analyzed a group of 145 glioma patients by testing for the three most frequent IDH mutations, IDH1 R132H, IDH1 R132C, and IDH2 R172K, through the competitive amplification of differentially melting amplicons (CADMA) polymerase chain reaction (PCR)...
2017: Klinická Onkologie: Casopis Ceské a Slovenské Onkologické Spolecnosti
https://www.readbyqxmd.com/read/29016943/radiologic-progression-of-glioblastoma-under-therapy-an-exploratory-analysis-of-avaglio
#5
Martha Nowosielski, Benjamin M Ellingson, Olivier L Chinot, Josep Garcia, Cedric Revil, Alexander Radbruch, Ryo Nishikawa, Warren P Mason, Roger Henriksson, Frank Saran, Philipp Kickingereder, Michael Platten, Thomas Sandmann, Lauren E Abrey, Timothy F Cloughesy, Martin Bendszus, Wolfgang Wick
Background: In this exploratory analysis of AVAglio, a randomized phase III clinical study that investigated the addition of bevacizumab (Bev) to radiotherapy/temozolomide in newly diagnosed glioblastoma, we aim to radiologically characterize glioblastoma on therapy until progression and investigate whether the type of radiologic progression differs between treatment arms and is related to survival and molecular data. Methods: Five progression types (PTs) were categorized using an adapted algorithm according to MRI contrast enhancement behavior in T1 and T2-weighted images in 621 patients (Bev, n= 299; placebo, n=322)...
September 1, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/29016925/divergent-evolution-of-temozolomide-resistance-in-glioblastoma-stem-cells-is-reflected-in-extracellular-vesicles-and-coupled-with-radiosensitization
#6
Delphine Garnier, Brian Meehan, Thomas Kislinger, Paul Daniel, Ankit Sinha, Bassam Abdulkarim, Ichiro Nakano, Janusz Rak
Background: Glioblastoma (GBM) is almost invariably fatal due to failure of standard therapy. The relapse of GBM following surgery, radiation and systemic temozolomide (TMZ) is attributed to the ability of glioma stem cells (GSCs) to survive, evolve and repopulate the tumor mass, events on which therapy exerts a poorly understood influence. Methods: Here we explore the molecular and cellular evolution of TMZ resistance as it emerges in vivo (xenograft models) in a series of human GSCs with either proneural (PN) or mesenchymal (MES) molecular characteristics...
July 28, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/29016808/molecular-differences-in-idh-wildtype-glioblastoma-according-to-mgmt-promoter-methylation
#7
Tobias Kessler, Felix Sahm, Ahmed Sadik, Damian Stichel, Anne Hertenstein, Guido Reifenberger, Angela Zacher, Michael Sabel, Ghazaleh Tabatabai, Joachim Steinbach, Ulrich Sure, Dietmar Krex, Anca-L Grosu, Melanie Bewerunge-Hudler, David Jones, Stefan M Pfister, Michael Weller, Christiane Opitz, Martin Bendszus, Andreas von Deimling, Michael Platten, Wolfgang Wick
Background: O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status is a predictive biomarker in glioblastoma. We investigated whether this marker furthermore defines a molecularly distinct tumor subtype with clinically different outcome. Methods: We analyzed copy number alteration (CNV) and methylation profiles of 1095 primary and 92 progressive Isocitrate dehydrogenase (IDH) wildtype glioblastomas, including paired samples from 49 patients. DNA mutation data from 182 glioblastoma samples of The Cancer Genome Atlas (TCGA) and RNA expression from 107 TCGA and 55 Chinese Glioma Genome Atlas samples were analyzed...
August 24, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/28990795/postprogression-survival-in-patients-with-glioblastoma-treated-with-concurrent-chemoradiotherapy-a-routine-care-cohort-study
#8
Paulina Majewska, Stefanos Ioannidis, Muhammad Hasan Raza, Nikhil Tanna, Helen Bulbeck, Mathew Williams
Glioblastoma is the commonest malignant brain tumor in adults. Most patients develop progressive disease before they die. However, survival after developing progressive disease is infrequently reported. We identified patients with histologically proven disease who were treated with concurrent chemoradiotherapy during 2006-2013. We analyzed overall survival (OS), progression-free survival and postprogression survival (PPS) in relation to age, O6-methylguanine-DNA methyltransferase promoter methylation and extent of surgical resection...
October 9, 2017: CNS Oncology
https://www.readbyqxmd.com/read/28980757/agt-activity-towards-intrastrand-cross-linked-dna-is-modulated-by-the-alkylene-linker
#9
Derek K O'Flaherty, Christopher James Wilds
DNA oligomers containing dimethylene and trimethylene intrastrand cross-links (IaCL) between the O4- and O6-atoms of neighboring thymidine (T) and 2´-deoxyguanosine (dG) residues have been prepared by solid-phase synthesis. UV thermal denaturing (Tm) experiments revealed that these IaCL had a destabilizing effect on the DNA duplex relative to the control. Circular dichroism spectroscopy suggested these IaCL induced minimal structural distortions. Susceptibility to dealkylation by reaction with various O6-alkylguanine DNA alkyltransferases (AGTs) from human and E...
October 5, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28943892/comparative-genomic-analysis-and-characteristics-of-nccp15740-the-major-type-of-enterotoxigenic-escherichia-coli-in-korea
#10
Taesoo Kwon, Si-Yun Chung, Young-Hee Jung, Su-Jin Jung, Sang-Gyun Roh, Je-Seop Park, Cheorl-Ho Kim, Won Kim, Young-Seok Bak, Seung-Hak Cho
BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) cause infectious diarrhea and diarrheal death. However, the genetic properties of pathogenic strains vary spatially and temporally, making prevention and treatment difficult. In this study, the genomic features of the major type of ETEC in Korea from 2003 to 2011 were examined by whole-genome sequencing of strain NCCP15740, and a comparative genomic analysis was performed with O6 reference strains. RESULTS: The assembled genome size of NCCP15740 was 4,795,873 bp with 50...
2017: Gut Pathogens
https://www.readbyqxmd.com/read/28940243/novel-contaminants-identified-in-fish-kills-in-the-red-river-watershed-2011-2013
#11
Tammy L Jones-Lepp, Vince Taguchi, Wayne Sovocool, Don Betowski, Patrick Dearmond, Brian Schumacher, Witold Winnik, Rick Mcmillin, Chris Armstrong
Provisional molecular weights and chemical formulas were assigned to four significant previously unidentified contaminants present during active fish kills in the Red River region of Oklahoma. The provisional identifications of these contaminants were determined using high-resolution liquid chromatography-time-of-flight mass spectrometry (LC-TOFMS), LC-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICRMS), and LC-ion trap mass spectrometry (LC-ITMS). Environmental water samples were extracted using a solid-phase extraction (SPE) method, and sediment samples were extracted using a modified sonication liquid extraction method...
September 21, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28933158/first-principles-fe-l2-3-edge-and-o-k-edge-xanes-and-xmcd-spectra-for-iron-oxides
#12
Michel Sassi, Carolyn I Pearce, Paul S Bagus, Elke Arenholz, Kevin M Rosso
X-ray absorption near-edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) spectroscopies are tools in widespread use for providing detailed local atomic structure, oxidation state, and magnetic structure information for materials and organometallic complexes. The analysis of these spectra for transition-metal L-edges is routinely performed on the basis of ligand-field multiplet theory because one- and two-particle mean-field ab initio methods typically cannot describe the multiplet structure...
October 2, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28914533/m%C3%A3-ssbauer-spectroscopic-characterization-of-iron-iii-polysaccharide-coordination-complexes-photochemistry-biological-and-photoresponsive-materials-implications
#13
Hendrik Auerbach, Giuseppe E Giammanco, Volker Schünemann, Alexis D Ostrowski, Carl J Carrano
While polycarboxylates and hydroxyl-acid complexes have long been known to be photoactive, simple carboxylate complexes which lack a significant LMCT band are not typically strongly photoactive. Hence, it was somewhat surprising that a series of reports demonstrated that materials synthesized from iron(III) and polysaccharides such as alginate (poly[guluronan-co-mannuronan]) or pectate (poly[galacturonan]) formed photoresponsive materials that convert from hydrogels to sols under the influence of visible light...
October 2, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28910418/the-effect-of-s-substitution-at-the-o6-guanine-site-on-the-structure-and-dynamics-of-a-dna-oligomer-containing-a-g-t-mismatch
#14
Elaine Ann Moore, Yao-Zhong Xu
The effect of S-substitution on the O6 guanine site of a 13-mer DNA duplex containing a G:T mismatch is studied using molecular dynamics. The structure, dynamic evolution and hydration of the S-substituted duplex are compared with those of a normal duplex, a duplex with S-substitution on guanine, but no mismatch and a duplex with just a G:T mismatch. The S-substituted mismatch leads to cell death rather than repair. One suggestion is that the G:T mismatch recognition protein recognises the S-substituted mismatch (GS:T) as G:T...
2017: PloS One
https://www.readbyqxmd.com/read/28903131/association-of-o6-methylguanine-dna-methyltransferase-protein-expression-with-postoperative-prognosis-and-adjuvant-chemotherapeutic-benefits-among-patients-with-stage-ii-or-iii-gastric-cancer
#15
Yifan Cao, Hao Liu, He Li, Chao Lin, Ruochen Li, Songyang Wu, Heng Zhang, Hongyong He, Weijuan Zhang, Jiejie Xu
Importance: Loss of O6-methylguanine-DNA methyltransferase (MGMT) protein expression has been reported in several malignant tumors and predicts dismal survival outcomes. In gastric cancer, existing studies on this topic are limited and the association between MGMT and fluorouracil-based adjuvant chemotherapy remains obscure. Objective: To investigate the postoperative prognostic significance of MGMT in patients with resectable gastric cancer and its responsiveness to fluorouracil-based adjuvant chemotherapy...
September 13, 2017: JAMA Surgery
https://www.readbyqxmd.com/read/28900805/mgmt-and-msh6-immunoexpression-for-functioning-pituitary-macroadenomas
#16
Alexander S G Micko, Adelheid Wöhrer, Romana Höftberger, Greisa Vila, Christine Marosi, Engelbert Knosp, Stefan Wolfsberger
PURPOSE: Knowledge of biological behavior is crucial for clinical management of functioning pituitary macroadenomas. For recurrent cases unresponsive to standard treatment, temozolomide (TMZ) has been used as a therapeutic alternative. MGMT (O6-methyl-guanine-DNA methyltransferase) and MSH6 (mutS homolog 6) immunoexpression have been linked to the response to TMZ treatment and MGMT immunoexpression has been additionally linked to early recurrence of non-functioning pituitary adenomas...
September 12, 2017: Pituitary
https://www.readbyqxmd.com/read/28898762/crystal-structure-of-a-novel-rna-motif-that-allows-for-precise-positioning-of-a-single-metal-ion
#17
Hiroki Kanazawa, Jiro Kondo
We have determined a crystal structure of an RNA duplex containing a novel metal-binding motif. The motif is composed of two sheared G○A base pairs, two unpaired A residues and four phosphate groups in close proximity. Four A residues make an A-A-A-A stacking column at the minor groove side and two G bases are highly inclined, thereby forming the pocket-shaped motif at the major groove side. In the present structure, a hydrated Sr(2+) ion exists in the pocket and binds to the O6 and N7 atoms of the two G bases and four phosphate groups...
November 2017: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/28862813/polyamine-is-a-critical-determinant-of-pseudomonas-chlororaphis-o6-for-gacs-dependent-bacterial-cell-growth-and-biocontrol-capacity
#18
Ju Yeon Park, Beom Ryong Kang, Choong-Min Ryu, Anne J Anderson, Young Cheol Kim
The Gac/Rsm network regulates at the transcriptional level many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays followed by specific growth studies and mutational analysis to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate, Pseudomonas chlororaphis O6. Growth of a gacS mutant was decreased significantly compared to that of the wild-type on ornithine and arginine, and the precursor of these amino acids, N-acetyl-l-glutamic acid...
September 1, 2017: Molecular Plant Pathology
https://www.readbyqxmd.com/read/28853558/mn3-single-molecule-magnets-and-mn6-mn9-clusters-from-the-use-of-methyl-2-pyridyl-ketone-oxime-in-manganese-phosphinate-and-phosphonate-chemistry
#19
Olajuyigbe A Adebayo, Khalil A Abboud, George Christou
The syntheses, structures, and magnetochemical properties are reported for five new Mn clusters: [Mn(III)3O(O2PPh2)3(mpko)3](ClO4) (1), [Mn(III)3O(O2PPh2)3(ppko)3](ClO4) (2) [Mn(III)6O2(OMe)4(O2PPh2)4(mpko)4](ClO4)2 (3), [Mn(III)8Mn(II)O6(O2CMe)7(O3PPh)2(mpko)3(H2O)] (4), and [Mn(III)2Mn(II)O(mpko)3(H2O)4(ClO4)2](ClO4) (5), where mpko(-) (or ppko(-)) is the anion of methyl (or phenyl) 2-pyridyl ketone oxime. 1 was obtained by carboxylate substitution on [Mn(III)3O(O2CMe)3(mpko)3](ClO4) by treatment with diphenylphosphinic acid (Ph2PO2H)...
August 30, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28834127/successful-treatment-of-metastatic-alveolar-rhabdomyosarcoma-with-mgmt-gene-promoter-methylation-by-temozolomide-based-combination-chemotherapy
#20
Mariko Kinoshita, Ai Yamada, Daisuke Sawa, Sachiyo Kamimura, Mitsuru Miyachi, Hiroshi Moritake
A 3-year-old male presented with a large retroperitoneal mass and multiple metastases. Biopsy results suggested alveolar rhabdomyosarcoma bearing a methylated O6-methylguanine-DNA methyltransferase (MGMT) gene promoter. Serum microRNA-206 levels were elevated and remained high after three cycles of vincristine, dactinomycin, and cyclophosphamide (VAC). Replacement of vincristine, irinotecan, and temozolomide (VIT) for VAC induced a marked tumor reduction and normalization of the miR-206 levels. The patient completed 14 cycles of VIT with local radiotherapy and has been in remission for 31 months...
August 17, 2017: Pediatric Blood & Cancer
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