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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
Marcus Unterrainer, Norbert Galldiks, Bogdana Suchorska, Lara-Caroline Kowalew, Vera Wenter, Christine Schmid-Tannwald, Maximilian Niyazi, Peter Bartenstein, Karl-Josef Langen, Nathalie L Albert
PURPOSE: In patients with brain metastasis, PET using labeled amino acids has gained clinical importance, mainly regarding the differentiation of viable tumor tissue from treatment-related effects. However, there is still limited knowledge concerning the uptake characteristics in patients with newly diagnosed and untreated brain metastases. Hence, we evaluated the uptake characteristics in these patients using dynamic O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) positron-emission-tomography (PET)...
October 6, 2016: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Manuel M Neidhardt, Manpreet Wolfrum, Stuart Beardsworth, Tobias Wöhrle, Wolfgang Frey, Angelika Baro, Cosima Stubenrauch, Frank Giesselmann, Sabine Laschat
Synthetic strategies were developed to prepare l-tyrosine-based ionic liquid crystals with structural variations at the carboxylic and phenolic OH groups as well as the amino functionality. Salt metathesis additionally led to counterion variation. The liquid-crystalline properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS, SAXS). The symmetrical ILC chlorides bearing the same alkyl chain at both the ester and ether but either an acyclic or cyclic guanidinium group displayed enantiotropic SmA2 mesophases with phase widths of 31-88 K irrespective of the head group...
October 13, 2016: Chemistry: a European Journal
Minmin Wang, Kyoko Toda, Hiroshi A Maeda
Plants produce various L-tyrosine (Tyr)-derived compounds that are of pharmaceutical or nutritional importance to humans. Tyr aminotransferase (TAT) catalyzes the reversible transamination between Tyr and 4-hydroxyphenylpyruvate (HPP), the initial step in the biosynthesis of many Tyr-derived plant natural products. Herein reported is the biochemical characterization and subcellular localization of TAT enzymes from the model plant Arabidopsis thaliana. Phylogenetic analysis showed that Arabidopsis has at least two homologous TAT genes, At5g53970 (AtTAT1) and At5g36160 (AtTAT2)...
October 7, 2016: Phytochemistry
Cheryl Chung, Thananunt Rojanasasithara, William Mutilangi, David Julian McClements
Anthocyanins are prone to chemical degradation and color fading in the presence of vitamin C. The potential of three amino acids (l-phenylalanine, l-tyrosine, l-tryptophan) and a polypeptide (ε-poly-l-lysine) in prolonging the color stability of purple carrot anthocyanins (0.025%) in model beverages (0.05% l-ascorbic acid, citric acid, pH 3.0) stored at elevated temperature (40°C/7 days) was examined. In the absence of amino acids or peptides, anthocyanin degraded at first-order reaction rate. Addition of amino acids or peptide (0...
March 1, 2017: Food Chemistry
Katrin Luck, Jan Jirschitzka, Sandra Irmisch, Meret Huber, Jonathan Gershenzon, Tobias G Köllner
BACKGROUND: Amino acid-derived aldoximes and nitriles play important roles in plant defence. They are well-known as precursors for constitutive defence compounds such as cyanogenic glucosides and glucosinolates, but are also released as volatiles after insect feeding. Cytochrome P450 monooxygenases (CYP) of the CYP79 family catalyze the formation of aldoximes from the corresponding amino acids. However, the majority of CYP79s characterized so far are involved in cyanogenic glucoside or glucosinolate biosynthesis and only a few have been reported to be responsible for nitrogenous volatile production...
October 4, 2016: BMC Plant Biology
Munmun Maiti, Ling-Jie Gao, Chunsheng Huang, Roger G Ptak, Michael G Murray, Steven De Jonghe, Piet Herdewijn
In an attempt to identify novel nucleoside phosphoramidate analogues for improving the anti-HCV activity of 2'-C-Me-uridine, we have synthesized for the first time a series of l-glutamic acid, l-serine, l-threonine and l-tyrosine containing aryloxyphosphoramidate prodrugs of 2'-C-Me-uridine. Evaluation of their activity against HCV revealed that they displayed very potent anti-HCV activity, with EC50 values that are in the same range as of Sofosbuvir.
September 21, 2016: Organic & Biomolecular Chemistry
Małgorzata Cieńska, Karolina Labus, Marcin Lewańczuk, Tomasz Koźlecki, Jolanta Liesiene, Jolanta Bryjak
Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis...
2016: PloS One
Ivano Alessandri, Irene Vassalini, Michela Bertuzzi, Nicolò Bontempi, Maurizio Memo, Alessandra Gianoncelli
SiO2/TiO2 core/shell (T-rex) beads were exploited as "all-in-one" building-block materials to create analytical assays that combine plasmon-free surface enhanced Raman scattering (SERS) and surface assisted laser desorption/ionization (SALDI) mass spectrometry (RaMassays). Such a multi-modal approach relies on the unique optical properties of T-rex beads, which are able to harvest and manage light in both UV and Vis range, making ionization and Raman scattering more efficient. RaMassays were successfully applied to the detection of small (molecular weight, M...
October 4, 2016: Scientific Reports
Jean-Yves Winum
The present patent discloses the identification of small-molecule fluorescent probes constituted by pteroic acid moiety connected to near-infrared (NIR) dye via amino acids. These folate receptor (FR) targeted conjugates were shown to have high affinity for tumors that overexpress FRs. A selected compound from this new class, pteroyl-L-tyrosine-S0456 (OTL-0038), displays high affinity and specificity for FRs and was shown (i) to accumulate in vivo in tumor cells expressing FRs, and (ii) to be non-toxic in mice at clinical dose x 1000...
October 4, 2016: Expert Opinion on Therapeutic Patents
Jose Rodríguez-Morató, Patricia Robledo, Julie-Anne Tanner, Anna Boronat, Clara Pérez-Mañá, C-Y Oliver Chen, Rachel F Tyndale, Rafael de la Torre
The dietary phenol tyrosol has been reported to be endogenously transformed into hydroxytyrosol, a potent antioxidant with multiple health benefits. In this work, we evaluated whether tyrosine hydroxylase (TH) and cytochrome P450s (CYPs) catalyzed this process. To assess TH involvement, Wistar rats were treated with α-methyl-L-tyrosine and tyrosol. Tyrosol was converted into hydroxytyrosol whilst α-methyl-L-tyrosine did not inhibit the biotransformation. The role of CYP was assessed in human liver microsomes (HLM) and tyrosol-to-hydroxytyrosol conversion was observed...
February 15, 2017: Food Chemistry
Abdelrahman Alabsi, Adel Charbel Khoudary, Wassim Abdelwahed
BACKGROUND: Depression has been linked to disruption in the cerebral levels of specific neurotransmitters. L-tyrosine is a precursor of more than one of the neurotransmitters affected by depression. Even though setbacks of monoamines precursors include high doses and low efficiency, many studies have suggested using L-tyrosine as antidepressant. PURPOSE: The purpose of this study was to explore the possible antidepressant effect of L-tyrosine loaded in a nanoparticle-designed formula, using behavioral tests in acute and chronic mild stress (CMS) models of depression in rats...
July 2016: Annals of Neurosciences
Suzan Mansourian, Jacob Corcoran, Anders Enjin, Christer Löfstedt, Marie Dacke, Marcus C Stensmyr
Feces is an abundant, rich source of energy, utilized by a myriad of organisms, not least by members of the order Diptera, i.e., flies. How Drosophila melanogaster reacts to fecal matter remains unclear. Here, we examined oviposition behavior toward a range of fecal samples from mammals native to the putative Southeast African homeland of the fly. We show that D. melanogaster display a strong oviposition aversion toward feces from carnivorous mammals but indifference or even attraction toward herbivore dung...
September 9, 2016: Current Biology: CB
Bettina Wingelhofer, Katharina Kreis, Severin Mairinger, Viktoria Muchitsch, Johann Stanek, Thomas Wanek, Oliver Langer, Claudia Kuntner
Aim of this study was to investigate if cellular [(18)F]FBPA uptake can be increased upon preloading with amino acids. [(18)F]FBPA uptake was assessed in HuH-7, CaCo-2 and B16-F1 cells pretreated with different concentrations or incubation times of L-BPA, L-tyrosine or L-DOPA. Without preloading, highest uptake of [(18)F]FBPA was observed in B16-F1 cells, followed by CaCo-2 cells and HuH-7 cells. In all cell lines higher [(18)F]FBPA accumulation (up to 1.65-fold) was obtained with increasing L-BPA, L-DOPA and L-tyrosine concentrations...
September 1, 2016: Applied Radiation and Isotopes
Kousuke Moriyama, Shono Naito, Rie Wakabayashi, Masahiro Goto, Noriho Kamiya
Cellular spheroids have been received much attention in the biological and biomedical fields, especially as a base material for drug assays, regenerative medicine, and tissue engineering. Hydrogels have potential for scalable preparation of spheroids because they provide a three-dimensional environment suitable for three-dimensional cell cultivation. Herein, we report the potential use of a redox-responsive hydrogel as a scaffold for preparation and recovery of spheroids. A hydrogel composed of poly(ethylene glycol) (PEG), which can be degraded using cysteine as a reducing agent under mild conditions, was prepared by mixing an octa-thiolated PEG derivative (8-arm PEG-SH), horseradish peroxidase and a small phenolic compound (Glycyl-L-tyrosine)...
September 12, 2016: Biotechnology Journal
Vladyslav O Kravchuk, Oleksandr V Savytskyi, Konstantin O Odynets, Vasyl V Mykuliak, Alexander I Kornelyuk
Cytoplasmic tyrosyl-tRNA synthetase (TyrRS) is one of the key enzymes of protein biosynthesis. TyrRSs of pathogenic organisms have gained attention as potential targets for drug development. Identifying structural differences between various TyrRSs will facilitate the development of specific inhibitors for the TyrRSs of pathogenic organisms. However, there is a deficiency in structural data for mammalian cytoplasmic TyrRS in complexes with substrates. In this work, we constructed spatial structure of full-length Bos taurus TyrRS (BtTyrRS) and its complexes with substrates by using the set of computational modeling techniques...
September 11, 2016: Journal of Biomolecular Structure & Dynamics
Carina Stegmayr, Ulrike Bandelow, Dennis Oliveira, Philipp Lohmann, Antje Willuweit, Christian Filss, Norbert Galldiks, Joachim H R Lübke, N Jon Shah, Johannes Ermert, Karl-Josef Langen
PURPOSE: O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) is an established tracer for the diagnosis of brain tumors with PET. This study investigates the influence of blood-brain barrier (BBB) permeability on (18)F-FET uptake in two rat glioma models and one human xenograft model. METHODS: F98 glioma, 9L gliosarcoma or human U87 glioblastoma cells were implanted into the striatum of 56 Fischer or RNU rats. Thereafter, animals were divided into a control group and a group receiving injections of the glucocorticoid dexamethasone (Dex)...
September 9, 2016: European Journal of Nuclear Medicine and Molecular Imaging
Mohammad Hasanzadeh, Sattar Sadeghi, Leyla Bageri, Ahad Mokhtarzadeh, Ayub Karimzadeh, Nasrin Shadjou, Soltanali Mahboob
A novel nanobiopolymer film was electrodeposited on the surface of glassy carbon through cyclic voltammetry from dopamine, β-cyclodextrin, and phosphate buffer solution in physiological pH (7.40). The electrochemical behavior of polydopamine-Beta-cyclodextrin modified glassy carbon electrode was investigated for electro-oxidation and determination of some amino acids (l-Cysteine, l-Tyrosine, l-Glycine, and l-Phenylalanine). The modified electrode was applied for selected amino acid detection at physiological pH using cyclic voltammetry, differential pulse voltammetry and chronoamperometry, chronocoulometery...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Sidsel Højklint Poulsen, Thomas Urup, Kirsten Grunnet, Ib Jarle Christensen, Vibeke Andrée Larsen, Michael Lundemann Jensen, Per Munck Af Rosenschöld, Hans Skovgaard Poulsen, Ian Law
BACKGROUND: Glioblastoma patients show a great variability in progression free survival (PFS) and overall survival (OS). To gain additional pretherapeutic information, we explored the potential of O-(2-(18)F-fluoroethyl)-L-tyrosine (FET) PET as an independent prognostic biomarker. METHODS: We retrospectively analyzed 146 consecutively treated, newly diagnosed glioblastoma patients. All patients were treated with temozolomide and radiation therapy (RT). CT/MR and FET PET scans were obtained postoperatively for RT planning...
August 23, 2016: European Journal of Nuclear Medicine and Molecular Imaging
Henry S Nzioki, Florence Oyosi, Cindy E Morris, Eylul Kaya, Alice L Pilgeram, Claire S Baker, David C Sands
Striga hermonthica (witchweed) is a parasitic weed that attacks and significantly reduces the yields of maize, sorghum, millet, and sugarcane throughout sub-Saharan Africa. Low cost management methods such as hand weeding, short crop rotations, trap cropping, or conventional biocontrol have not been effective. Likewise, Striga-tolerant or herbicide-resistant maize cultivars are higher yielding, but are often beyond the economic means of sustenance farmers. The fungal pathogen, Fusarium oxysporum f.sp. strigae, has been the object of numerous studies to develop Striga biocontrol...
2016: Frontiers in Plant Science
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