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https://www.readbyqxmd.com/read/28077650/melanin-or-melanin-like-substance-interacts-with-the-n-terminal-portion-of-prion-protein-and-inhibits-abnormal-prion-protein-formation-in-prion-infected-cells
#1
Taichi Hamanaka, Keiko Nishizawa, Yuji Sakasegawa, Ayumi Oguma, Kenta Teruya, Hiroshi Kurahashi, Hideyuki Hara, Suehiro Sakaguchi, Katsumi Doh-Ura
Prion diseases are progressive fatal neurodegenerative illnesses caused by the accumulation of transmissible abnormal prion protein (PrP). To find treatments for prion diseases, we searched for substances from natural resources that inhibit abnormal PrP formation in prion-infected cells. We found that high-molecular-weight components from insect cuticle extracts reduced abnormal PrP levels. The chemical nature of these components was consistent with that of melanin. In fact, synthetic melanin produced from tyrosine or 3-hydroxy-l-tyrosine inhibited abnormal PrP formation...
January 11, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28064504/development-of-l-tyrosine-based-enzyme-responsive-amphiphilic-poly-ester-urethane-nanocarriers-for-multiple-drug-delivery-to-cancer-cells
#2
Rajendra Aluri, Manickam Jayakannan
New classes of enzymatic-biodegradable amphiphilic poly(ester-urethane)s were designed and developed from l-tyrosine amino acid resources and their self-assembled nanoparticles were employed as multiple drug delivery vehicles in cancer therapy. The amine and carboxylic acid functional groups in l-tyrosine were converted into dual functional ester-urethane monomers and they were subjected to solvent free melt polycondensation with hydrophilic polyethylene glycols to produce comb-type poly(ester-urethane)s. The phenolic unit in the l-tyrosine was anchored with hydrophobic alkyl side chain to bring appropriate amphiphilicity in the polymer geometry to self-assemble them as stable nanoscaffolds in aqueous medium...
January 9, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28045730/neurosarcoidosis-on-fet-and-fdg-pet-ct
#3
Mico Chan, Edward Hsiao
O-(2-fluoroethyl)-L-tyrosine (FET) PET/CT is a promising imaging modality for brain tumor imaging because of its reported high sensitivity for biologically active tumor tissue. We present a case of biopsy-proven neurosarcoidosis showing FET uptake. It is an important cause of false-positive uptake on FET PET/CT.
December 30, 2016: Clinical Nuclear Medicine
https://www.readbyqxmd.com/read/28039366/the-use-of-o-2-18f-fluoroethyl-l-tyrosine-pet-in-the-diagnosis-of-gliomas-located-in-the-brainstem-and-spinal-cord
#4
Caroline Tscherpel, Veronika Dunkl, Garry Ceccon, Gabriele Stoffels, Natalie Judov, Marion Rapp, Philipp T Meyer, Elena Rota Kops, Johannes Ermert, Gereon R Fink, Nadim J Shah, Karl-Josef Langen, Norbert Galldiks
BACKGROUND: Despite an increasing number of O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) PET studies in supratentorial gliomas, studies regarding the usefulness of (18)F-FET PET in brainstem and spinal cord gliomas to date remain scarce. METHODS: Thirty-six (18)F-FET PET scans were performed in 29 patients with brainstem (n = 29 scans) or spinal cord glioma (n = 7 scans). In 32 of 36 PET scans, a dynamic acquisition was performed. Fifteen scans in 15 patients were performed to assess newly diagnosed lesions, and 21 scans were obtained during follow-up: for diagnosing tumor progression (n = 15 scans in 14 patients) as well as for treatment monitoring (n = 6 scans in 3 patients)...
December 29, 2016: Neuro-oncology
https://www.readbyqxmd.com/read/28030820/unsupervised-consensus-cluster-analysis-of-18f-fluoroethyl-l-tyrosine-positron-emission-tomography-identified-textural-features-for-the-diagnosis-of-pseudoprogression-in-high-grade-glioma
#5
Sied Kebir, Zain Khurshid, Florian C Gaertner, Markus Essler, Elke Hattingen, Rolf Fimmers, Björn Scheffler, Ulrich Herrlinger, Ralph A Bundschuh, Martin Glas
RATIONALE: Timely detection of pseudoprogression (PSP) is crucial for the management of patients with high-grade glioma (HGG) but remains difficult. Textural features of O-(2-[18F]fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) mirror tumor uptake heterogeneity; some of them may be associated with tumor progression. METHODS: Fourteen patients with HGG and suspected of PSP underwent FET-PET imaging. A set of 19 conventional and textural FET-PET features were evaluated and subjected to unsupervised consensus clustering...
December 24, 2016: Oncotarget
https://www.readbyqxmd.com/read/28028844/improved-tlc-bioautographic-assay-for-qualitative-and-quantitative-estimation-of-tyrosinase-inhibitors-in-natural-products
#6
Jinge Zhou, Qingjiu Tang, Tao Wu, Zhihong Cheng
INTRODUCTION: TLC bioautography for tyrosinase inhibitors has made recent progress; however, an assay with a relative low consumption of enzyme and quantitative capability would greatly advance the efficacy of related TLC bioautographic assays. OBJECTIVE: An improved TLC bioautographic assay for detecting tyrosinase inhibitors was developed and validated in this study. METHODS: L-DOPA (better water-solubility than L-tyrosine) was used as the substrate instead of reported L-tyrosine...
December 28, 2016: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/28025081/biochemical-characterization-of-tyra-enzymes-from-ignicoccus-hospitalis-and-haemophilus-influenzae-a-comparative-study-of-the-bifunctional-and-monofunctional-dehydrogenase-forms
#7
Irina Shlaifer, Peter Kojo Quashie, Hyun Young Kim, Joanne L Turnbull
Biosynthesis of l-tyrosine (l-Tyr) is directed by the interplay of two enzymes. Chorismate mutase (CM) catalyzes the rearrangement of chorismate to prephenate, which is then converted to hydroxyphenylpyruvate by prephenate dehydrogenase (PD). This work reports the first characterization of the independently expressed PD domain of bifunctional CM-PD from the crenarchaeon Ignicoccus hospitalis and the first functional studies of both full-length CM-PD and the PD domain from the bacterium Haemophilus influenzae...
December 24, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28007948/genome-metabolite-associations-revealed-low-heritability-high-genetic-complexity-and-causal-relations-for-leaf-metabolites-in-winter-wheat-triticum-aestivum
#8
Andrea Matros, Guozheng Liu, Anja Hartmann, Yong Jiang, Yusheng Zhao, Huange Wang, Erhard Ebmeyer, Viktor Korzun, Ralf Schachschneider, Ebrahim Kazman, Johannes Schacht, Friedrich Longin, Jochen Christoph Reif, Hans-Peter Mock
We investigated associations between the metabolic phenotype, consisting of quantitative data of 76 metabolites from 135 contrasting winter wheat (Triticum aestivum) lines, and 17 372 single nucleotide polymorphism (SNP) markers. Metabolite profiles were generated from flag leaves of plants from three different environments, with average repeatabilities of 0.5-0.6. The average heritability of 0.25 was unaffected by the heading date. Correlations among metabolites reflected their functional grouping, highlighting the strict coordination of various routes of the citric acid cycle...
December 22, 2016: Journal of Experimental Botany
https://www.readbyqxmd.com/read/27978642/synthesis-of-the-bioherbicidal-fungus-metabolite-macrocidin-a
#9
Robert G Haase, Rainer Schobert
The second total synthesis of macrocidin A afforded the bioherbicidal fungal metabolite in 16 steps starting from doubly protected l-tyrosine. The 3-octanoyl side chain with the α-methyl group and an ω-bromo epoxide already in place was attached to the tetramic acid via a Yoshii-Yoda acylation, and the macrocycle was eventually closed in 55% yield by a Williamson etherification between the phenolate and the epoxy bromide.
December 16, 2016: Organic Letters
https://www.readbyqxmd.com/read/27924409/antioxidants-reverse-the-changes-in-energy-metabolism-of-rat-brain-after-chronic-administration-of-l-tyrosine
#10
Brena P Teodorak, Giselli Scaini, Milena Carvalho-Silva, Lara M Gomes, Letícia J Teixeira, Joyce Rebelo, Samira D T De Prá, Neila Zeni, Patrícia F Schuck, Gustavo C Ferreira, Emilio L Streck
Tyrosinemia type II is a rare autosomal recessive disease caused by deficiency of hepatic tyrosine aminotransferase and is associated with neurologic and development difficulties in numerous patients. Considering that the mechanisms underlying the neurological dysfunction in hypertyrosinemic patients are poorly known and that high concentrations of tyrosine provoke mitochondrial dysfunction and oxidative stress, in the present study we investigated the in vivo influence of antioxidants (N-acetylcysteine, NAC; and deferoxamine, DFX) administration on the inhibitory effects on parameters of energy metabolism in cerebral cortex, hippocampus and striatum of rats, provoked by chronic administration of L...
December 6, 2016: Metabolic Brain Disease
https://www.readbyqxmd.com/read/27910199/reverse-phase-compatible-tlc-bioautography-for-detection-of-tyrosinase-inhibitors
#11
Paula García, I Ayelen Ramallo, Ricardo L E Furlan
INTRODUCTION: Reverse phase chromatography and bioautographic assays are key tools for natural product bioguided isolation; however, their direct coupling has not been fully achieved. OBJECTIVES: To develop a bioautographic assay to detect tyrosinase inhibitors present in complex matrices sorbed on reverse phase (RP) TLC-plates that can be used for bioguided isolation of bioactive compounds. METHODS: Enzyme gel entrapment with an amphiphilic copolymer was used for assay development...
December 2, 2016: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/27908494/simultaneous-microextraction-of-inorganic-iodine-and-iodinated-amino-acids-by-miniaturized-matrix-solid-phase-dispersion-with-molecular-sieves-and-ionic-liquids
#12
Jun Cao, Li-Qing Peng, Jing-Jing Xu, Li-Jing Du, Qi-Dong Zhang
This study presents an effective method of using miniaturized matrix solid phase dispersion (MSPD) for the microextraction of inorganic iodine and iodinated amino acids from seaweed samples. Quantification of the target analytes was performed by ultrahigh performance liquid chromatography with UV detection. Molecular sieve (SBA-15) was chosen as the dispersing adsorbent with an ionic liquid (1-dodecyl-3-methylimidazolium bromide) as the elution solvent. The experimental conditions for the MSPD, such as the type of sorbent, ratio of sorbent to sample, type and concentration of the elution solvent, and grinding time were evaluated and optimized...
December 16, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27871872/biotechnological-production-of-aromatic-compounds-of-the-extended-shikimate-pathway-from-renewable-biomass
#13
Jin-Ho Lee, Volker F Wendisch
Aromatic chemicals that contain an unsaturated ring with alternating double and single bonds find numerous applications in a wide range of industries, e.g. paper and dye manufacture, as fuel additives, electrical insulation, resins, pharmaceuticals, agrochemicals, in food, feed and cosmetics. Their chemical production is based on petroleum (BTX; benzene, toluene, and xylene), but they can also be obtained from plants by extraction. Due to petroleum depletion, health compliance, or environmental issues such as global warming, the biotechnological production of aromatics from renewable biomass came more and more into focus...
November 18, 2016: Journal of Biotechnology
https://www.readbyqxmd.com/read/27864137/intergenomic-evolution-and-metabolic-cross-talk-between-rumen-and-thermophilic-autotrophic-methanogenic-archaea
#14
M Bharathi, P Chellapandi
Methanobrevibacter ruminantium M1 (MRU) is a rumen methanogenic archaean that can be able to utilize formate and CO2/H2 as growth substrates. Extensive analysis on the evolutionary genomic contexts considered herein to unravel its intergenomic relationship and metabolic adjustment acquired from the genomic content of Methanothermobacter thermautotrophicus ΔH. We demonstrated its intergenomic distance, genome function, synteny homologs and gene families, origin of replication, and methanogenesis to reveal the evolutionary relationships between Methanobrevibacter and Methanothermobacter...
November 15, 2016: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/27864061/melanogenesis-inhibits-respiration-in-b16-f10-melanoma-cells-whereas-enhances-mitochondrial-cell-content
#15
Willian Vanderlei Meira, Tassiele Andréa Heinrich, Silvia Maria Suter Correia Cadena, Glaucia Regina Martinez
Melanoma is a rare and aggressive skin tumor; the survival of patients diagnosed late is fairly low. This high mortality rate is due to the characteristics of the cells that allow them to be resistant to radiotherapy and conventional chemotherapy, besides of being able to evade the immune system. Melanin, the pigment responsible for skin, hair and eye color, seems to be involved in this resistance. The main function of melanin is to protect the cells against ultraviolet (UV) light by absorbing this radiation and reactive oxygen species (ROS) scavenging...
January 1, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/27853813/radiation-injury-vs-recurrent-brain-metastasis-combining-textural-feature-radiomics-analysis-and-standard-parameters-may-increase-18-f-fet-pet-accuracy-without-dynamic-scans
#16
Philipp Lohmann, Gabriele Stoffels, Garry Ceccon, Marion Rapp, Michael Sabel, Christian P Filss, Marcel A Kamp, Carina Stegmayr, Bernd Neumaier, Nadim J Shah, Karl-Josef Langen, Norbert Galldiks
OBJECTIVES: We investigated the potential of textural feature analysis of O-(2-[(18)F]fluoroethyl)-L-tyrosine ((18)F-FET) PET to differentiate radiation injury from brain metastasis recurrence. METHODS: Forty-seven patients with contrast-enhancing brain lesions (n = 54) on MRI after radiotherapy of brain metastases underwent dynamic (18)F-FET PET. Tumour-to-brain ratios (TBRs) of (18)F-FET uptake and 62 textural parameters were determined on summed images 20-40 min post-injection...
November 16, 2016: European Radiology
https://www.readbyqxmd.com/read/27822460/the-transcriptome-of-exophiala-dermatitidis-during-ex-vivo-skin-model-infection
#17
Caroline Poyntner, Barbara Blasi, Elsa Arcalis, Ursula Mirastschijski, Katja Sterflinger, Hakim Tafer
The black yeast Exophiala dermatitidis is a widespread polyextremophile and human pathogen, that is found in extreme natural habitats and man-made environments such as dishwashers. It can cause various diseases ranging from phaeohyphomycosis and systemic infections, with fatality rates reaching 40%. While the number of cases in immunocompromised patients are increasing, knowledge of the infections, virulence factors and host response is still scarce. In this study, for the first time, an artificial infection of an ex-vivo skin model with Exophiala dermatitidis was monitored microscopically and transcriptomically...
2016: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/27817203/chemical-composition-and-biological-activities-of-the-essential-oil-from-rubus-pungens-var-oldhamii
#18
Yaojie Zhang, Jiajing Chen, Lizhi Wang, Jingjing Cao, Lishan Xu
This paper presents a study on chemical composition, antimicrobial, antioxidant and tyrosinase inhibitory properties of the essential oil from leaves of Rubus pungens var. oldhamii (REO). The major component of the REO is sesquiterpenes (36.04%), which consists of 1,5-Cyclooctadiene,3-(1-me thylallyl)-(8CI)(17.66%), 5,6-Diethenyl-1-methylcyclohexene (12%), (+) - γ-Elemene (10.48%) and β-Caryophyllene (8.39%).The REO is shown to be moderately active against Staphylococcus aureus, Aspergillus niger and Penicillium glaucum, and has weak antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay...
November 6, 2016: Natural Product Research
https://www.readbyqxmd.com/read/27780313/synthesis-carbonic-anhydrase-i-and-ii-isoenzymes-inhibition-properties-and-antibacterial-activities-of-novel-tetralone-based-1-4-benzothiazepine-derivatives
#19
Mustafa Ceylan, Umit M Kocyigit, Necibe Canan Usta, Belma Gürbüzlü, Yusuf Temel, Saleh H Alwasel, İlhami Gülçin
Benzothiazepine compounds have a wide range of applications such as antibacterial, antidepressants, anticonvulsants, antihypertensives, antibiotics, antifungal, hypnotic, enzyme inhibitors, antitumor, anticancer and anti-HIV agents. In this study, the synthesis of novel tetralone-based benzothiazepine derivatives (1-16) and their in vitro antibacterial activity and human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibitory effects were investigated. Both isoenzymes were purified by sepharose-4B-l-tyrosine-sulfanilamide affinity chromatography from fresh human red blood cells...
October 25, 2016: Journal of Biochemical and Molecular Toxicology
https://www.readbyqxmd.com/read/27769279/suspected-recurrence-of-brain-metastases-after-focused-high-dose-radiotherapy-can-18-f-fet-pet-overcome-diagnostic-uncertainties
#20
Alexander Romagna, Marcus Unterrainer, Christine Schmid-Tannwald, Matthias Brendel, Jörg-Christian Tonn, Silke Birgit Nachbichler, Alexander Muacevic, Peter Bartenstein, Friedrich-Wilhelm Kreth, Nathalie Lisa Albert
BACKGROUND: After focused high dose radiotherapy of brain metastases, differentiation between tumor recurrence and radiation-induced lesions by conventional MRI is challenging. This study investigates the usefulness of dynamic O-(2-(18)F-Fluoroethyl)-L-Tyrosine positron emission tomography ((18)F-FET PET) in patients with MRI-based suspicion of tumor recurrence after focused high dose radiotherapy of brain metastases. METHODS: Twenty-two patients with 34 brain metastases (median age 61...
October 21, 2016: Radiation Oncology
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