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1
Rivenc, François. "Mai, Mao, Milner." Critique 749, no. 10 (2009): 916. http://dx.doi.org/10.3917/criti.749.0916.
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Yan, Bing, Hongxia Zhu, and Lei Zhou. "Novel Molecular Precursor of Lanthanide Complexes with LongChain Mono Cis-Butene Dicarboxylate to the Controlled Synthesis of Y2O3:Eu3+ Phosphors." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1191–98. http://dx.doi.org/10.1166/jnn.2008.18170.
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Maleic anhydride was modified with long chain alcohols (1-hexadecanol, 1-octadecanol, 1-eicosanol and docosyl) to their corresponding amphiphilic mono-L cis-butene dicarboxylates (L = hexadecyl, octadecyl, eicosyl and docosyl). Subsequently, corresponding amphiphilic lanthanide (Y3+, Eu3+) complexes with these four mono-L cis-butene dicarboxylate ligands [Ln(L′)3, Ln = Eu, Y; L′ = MAH, MAO, MAE, MAD] were synthesized. Then, under heating at various temperatures (700, 800, 900, 1000, and 1,100 °C), twenty kinds of nanosized Y2O3:Eu3+ phosphors were prepared using these four as-derived amphiphilic lanthanide (Y3+, Eu3+) complexes as precursors. All four complexes can form nanosized micelle-like aggregates by special self-assembly. Results show that, under heating at 1,000 °C, the four Y2O3:Eu3+ phosphors present more regular dispersion particle-like morphology, and the particle size is in the range of 30–80 nm. They exhibit an especially strong emission at 609 nm, and the luminescence intensity of the sample derived from MAD at 1,000 °C is best.
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Meiyasa, F., N. Taringan, K. U. Henggu, Y. R. Tega, S. Ndahawali, K. E. Zulfamy, M. N. B. Saputro, and I. Priyastiti. "Biological activities of macroalgae in the Moudulung waters: bioactive compounds and antioxidant activity." Food Research 8, no. 1 (January 13, 2024): 82–91. http://dx.doi.org/10.26656/fr.2017.8(1).050.
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This study aimed to determine the bioactive compounds and antioxidant activity of macroalgae in Moudolung Waters. The bioactive compounds in seven samples of macroalgae were extracted with methanol. Analysis of macroalgae bioactive compounds was carried out qualitatively by determining the presence of bioactive compounds including alkaloids, flavonoids, saponins, tannins, phenol hydroquinone, and steroids/ terpenoids. antioxidant activity was carried out using the DPPH (2,2-diphenyl-1-picrylhydrazyl-hydrate) method. Data were analyzed descriptively using Microsoft Excel and all data are expressed as mean. The results showed that these seven macroalgae species have bioactive compounds such as alkaloids, flavonoids, saponins, tannins, phenol hydroquinone, and steroids/terpenoids which function as antioxidants. The highest antioxidant activity was the MA6 (Turbinaria ornate) followed by MA1 (Hormopysa triquetra), MA4 (Ulva flexuosa syn. Enteromorpha flexuosa), MA5 (Eucheuma spinosum), MA2 (Sargassum muticum), MA3 (Gracilaria corticate), and MA7 (Ulva reticulata) were 75.25 mg/mL, 90.31 mg/mL, 134.52 mg/mL, 200.22 mg/mL, 216.91 mg/mL, 259.16 mg/mL, and 270.42 mg/mL, respectively. The results suggested that Turbinaria ornate and Hormopysa triquetra could be used as an important substitute for functional ingredients in foods and pharmaceuticals or nutraceuticals.
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Zedong, Mao. "Mao on Mao." Chinese Sociology & Anthropology 28, no. 1 (October 1995): 33. http://dx.doi.org/10.2753/csa0009-4625280133.
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Limandal, Hüsnü Kamil, and Taha Özkara. "FACTORS AFFECTING MAJOR ADVERSE EFFECTS AFTER CORONARY ARTERY BYPASS SURGERY." Kocatepe Tıp Dergisi 25, no. 2 (September 26, 2023): 221–26. http://dx.doi.org/10.18229/kocatepetip.1315953.
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OBJECTIVE: The present study aimed to evaluate the patient population who underwent coronary artery bypass grafting (CABG) operation in terms of mortality and major adverse effects (MAE) incidence and examine the factors affecting MAE incidence. MATERIAL AND METHODS: 169 consecutive patients who underwent CABG surgery between January 2017 and December 2019 were retrospectively analyzed. Mortality, myocardial infarction, reoperation, cardiac tamponade, stroke, renal failure, sternal infection, need for extracorporeal membrane oxygenator and cardio pulmonary resuscitation were defined as MAO. RESULTS: The mean age of the patients was 63.19 ±0.72 years, the mean duration of cardiopulmonary bypass (CPB) was 106.95 ±27 minutes, and the mean duration of aortic cross-clamp was 44.87 ±1.05 minutes. Extracorporeal membrane oxygenator support was provided to 11 (6.5%) patients, 7 (4.1%) patients underwent reoperation, 5 (3%) patients experienced a postoperative stroke, 5 (3%) patients required cardiopulmonary resuscitation, and postoperative myocardial infarction was observed in 1 (0.6%) patient. In total, MAE was determined in 28 (16.6%) patients. Mortality occurred in 9 (5.3%) patients. In the univariate analysis, Euroscore, mean arterial pressure during CPB, and ultrafiltration volume were associated with MAE (p=0.004, p=0.026, and p=0.037, respectively). However, in multivariate analysis, only Euroscore (odds ratio: 1.453, 95% CI 1.166-1.811 p=0.001) and ultrafiltration volume (odds ratio:-0.002, 95% CI 0.996-1 p=0.04) were correlated to MAE. CONCLUSIONS: In our study, we observed that high Euroscore levels increased not only mortality but also the incidence of MAO, and increased ultrafiltration volumes reduced the incidence of MAO. We believe that it should be kept in mind during CABG surgery that appropriate ultrafiltration and CPB strategy can reduce the incidence of MAO.
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Liu, Liyan. "The Man Who Molded Mao." Modern China 32, no. 4 (October 2006): 483–512. http://dx.doi.org/10.1177/0097700406290790.
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YIN, ZHI-LONG, and BEN-YONG MAO. "A review of Caryanda viridis - species group (Orthoptera: Acrididae) with a new species." Zootaxa 5263, no. 4 (April 11, 2023): 505–19. http://dx.doi.org/10.11646/zootaxa.5263.4.2.
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A new species of Caryanda viridis- species group, i.e. Caryanda biserrata Mao et Yin sp. nov. is described and illustrated. C. xinpingensis Mao, 2017 is included into C. viridis- species group, and C. viridoides Mao, Ren & Ou, 2011 is removed from it. C. viridis- species group presently contains six species: C. viridis (Zheng & Mao, 1996), C. dehongensis Mao, Xu & Yang, 2003, C. albomaculata Mao, Ren & Ou, 2007, C. eshana Mao, 2015, C. xinpingensis Mao, 2017 and C. biserrata Mao et Yin sp. nov.. The key to the six species of C. viridis- species group is updatad.
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Hubálek, Frantisek, Claudia Binda, Ashraf Khalil, Min Li, Andrea Mattevi, Neal Castagnoli, and Dale E. Edmondson. "Demonstration of Isoleucine 199 as a Structural Determinant for the Selective Inhibition of Human Monoamine Oxidase B by Specific Reversible Inhibitors." Journal of Biological Chemistry 280, no. 16 (February 14, 2005): 15761–66. http://dx.doi.org/10.1074/jbc.m500949200.
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Several reversible inhibitors selective for human monoamine oxidase B (MAO B) that do not inhibit MAO A have been described in the literature. The following compounds: 8-(3-chlorostyryl)caffeine, 1,4-diphenyl-2-butene, andtrans,trans-farnesol are shown to inhibit competitively human, horse, rat, and mouse MAO B withKivalues in the low micromolar range but are without effect on either bovine or sheep MAO B or human MAO A. In contrast, the reversible competitive inhibitor isatin binds to all known MAO B and MAO A with similar affinities. Sequence alignments and the crystal structures of human MAO B in complex with 1,4-diphenyl-2-butene or withtrans,trans-farnesol provide molecular insights into these specificities. These inhibitors span the substrate and entrance cavities with the side chain of Ile-199 rotated out of its normal conformation suggesting that Ile-199 is gating the substrate cavity. Ile-199 is conserved in all known MAO B sequences except bovine MAO B, which has Phe in this position (the sequence of sheep MAO B is unknown). Phe is conserved in the analogous position in MAO A sequences. The human MAO B I199F mutant protein of MAO B binds to isatin (Ki= 3 μm) but not to the three inhibitors listed above. The crystal structure of this mutant demonstrates that the side chain of Phe-199 interferes with the binding of those compounds. This suggests that the Ile-199 “gate” is a determinant for the specificity of these MAO B inhibitors and provides a molecular basis for the development of MAO B-specific reversible inhibitors without interference with MAO A function in neurotransmitter metabolism.
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Cho, Hyun-U., Sunpil Kim, Jeongeun Sim, Seulkee Yang, Heeyoung An, Min-Ho Nam, Dong-Pyo Jang, and C. Justin Lee. "Redefining differential roles of MAO-A in dopamine degradation and MAO-B in tonic GABA synthesis." Experimental & Molecular Medicine 53, no. 7 (July 2021): 1148–58. http://dx.doi.org/10.1038/s12276-021-00646-3.
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AbstractMonoamine oxidase (MAO) is believed to mediate the degradation of monoamine neurotransmitters, including dopamine, in the brain. Between the two types of MAO, MAO-B has been believed to be involved in dopamine degradation, which supports the idea that the therapeutic efficacy of MAO-B inhibitors in Parkinson’s disease can be attributed to an increase in extracellular dopamine concentration. However, this belief has been controversial. Here, by utilizing in vivo phasic and basal electrochemical monitoring of extracellular dopamine with fast-scan cyclic voltammetry and multiple-cyclic square wave voltammetry and ex vivo fluorescence imaging of dopamine with GRABDA2m, we demonstrate that MAO-A, but not MAO-B, mainly contributes to striatal dopamine degradation. In contrast, our whole-cell patch-clamp results demonstrated that MAO-B, but not MAO-A, was responsible for astrocytic GABA-mediated tonic inhibitory currents in the rat striatum. We conclude that, in contrast to the traditional belief, MAO-A and MAO-B have profoundly different roles: MAO-A regulates dopamine levels, whereas MAO-B controls tonic GABA levels.
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Prinsloo, Denise, Sandra van Dyk, Anél Petzer, and Jacobus P. Petzer. "Monoamine Oxidase Inhibition by Kavalactones from Kava (Piper Methysticum)." Planta Medica 85, no. 14/15 (September 20, 2019): 1136–42. http://dx.doi.org/10.1055/a-1008-9491.
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AbstractMonoamine oxidases (MAOs) are key metabolic enzymes for neurotransmitter and dietary amines and are targets for the treatment of neuropsychiatric and neurodegenerative disorders. This study examined the MAO inhibition potential of kavain and other kavalactones from the roots of kava (Piper methysticum), a plant that has been used for its anxiolytic properties. (±)-Kavain was found to be a good potency in vitro inhibitor of human MAO-B with an IC50 of 5.34 µM. (±)-Kavain is a weaker MAO-A inhibitor with an IC50 of 19.0 µM. Under the same experimental conditions, the reference MAO inhibitor, curcumin, displays IC50 values of 5.01 µM and 2.55 µM for the inhibition of MAO-A and MAO-B, respectively. It was further established that (±)-kavain interacts reversibly and competitively with MAO-A and MAO-B with enzyme-inhibitor dissociation constants (Ki) of 7.72 and 5.10 µM, respectively. Curcumin in turn, displays a Ki value of 3.08 µM for the inhibition of MAO-A. Based on these findings, other kavalactones (dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin) were also evaluated as MAO inhibitors in this study. Yangonin proved to be the most potent MAO inhibitor with IC50 values of 1.29 and 0.085 µM for MAO-A and MAO-B, respectively. It may be concluded that some of the central effects (e.g., anxiolytic) of kava may be mediated by MAO inhibition.
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Soni, Shivani, Hui Ju Tseng, Yan Yang, Goar Smbatayan, Unnati Hemant Shah, Jae Ho Lo, Joshua Millstein, et al. "Abstract 4671: MAO A, MAO B inhibitors and NMI for colon cancer therapy." Cancer Research 83, no. 7_Supplement (April 4, 2023): 4671. http://dx.doi.org/10.1158/1538-7445.am2023-4671.
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Abstract Background: Mitochondrial MAO A and MAO B isoenzymes catalyze oxidative deamination of neuroactive and vasoactive monoamines in CNS and peripheral tissues. MAO A inhibitors have been used as antidepressants; MAO B inhibitors have been used for Parkinson’s disease. Recently, we and others have shown MAO inhibitors can be repurposed for cancer therapy. This study focused on the MAO inhibitors as a novel therapeutic strategy for CRC utilizing patient derived xenograft (PDX) platform which recapitulates the patient’s molecular characteristics. Methods and Results: CRC PDX models were selected from our repository based on MAO A and B expression and activity. To establish two PDX models with high or low MAO A/B activity we implanted patient’s tumor samples (F0 generation) with high MAO A/B activity (MAO high) or low MAO A/B activity (MAO low) in 8 weeks NSG mice (F1 generation). F1 MAO low PDX model showed substantially slower tumor growth rates as compared to MAO high PDX model (200 days vs 65 days), suggesting the role of MAOs in CRC growth. For each PDX model trial, tumors were pooled from 6 F1 PDX mice and implanted in 30 NSG mice (F2 generation). There were five mice in each of experimental groups: one control arm (vehicle: 67% PEG 400, 33% saline) and treatment arms (i.p. for 21 days): 1. MAO A inhibitors: clorygyline: 50mg/kg; 2. Near infrared dye conjugated MAO A inhibitor (NMI): 5 mg/kg; 3. MAO B inhibitor: deprenyl 10mg/kg;4. MAO A & B inhibitor: phenelzine (30mg/kg). MAO high PDX cohort showed significant reduction in tumor volume in mice treated with MAO A inhibitors clorygyline (p=0.009); NMI (p=0.053) and MAO B inhibitor deprenyl (p=0.022), phenelzine (p= 0.097) when compared to control. Angiogenesis marker CD31 staining of tumor tissues showed significant reduction in mice treated with clorygyline and NMI. Additionally, Ki 67 staining demonstrated considerable decrease in cell proliferation and TUNEL assay exhibited increase in apoptosis in tumor treated with clorygyline and NMI. RNA sequencing revealed 50 differentially expressed genes (DEGs) between clorygyline treated tumors and control, 171 between NMI treated and control group (padj <0.05, |fold change| >=1.5). Ingenuity Pathway Analysis showed alterations in pathways including oxidative phosphorylation, sirtuin pathway, estrogen receptor signaling, and mitochondrial dysfunction. NMI showed same efficacy with no toxicity compared to clorygyline even at 10 times lower dose in MAO high PDX model. No significant difference in tumor size was found among treatment groups in MAO low PDX cohort. Conclusion: Our CRC PDX studies showed both MAO A and B are important for tumor growth and are potential target for therapy. Both MAO A and B inhibitors and NMI (NIR-conjugated MAO an inhibitor, clorgyline) reduced tumor growth. IHC and RNA seq data shows MAO A inhibitor and NMI has similar mechanisms, though NMI is more effective than clorygyline and also can be used for diagnosis. Citation Format: Shivani Soni, Hui Ju Tseng, Yan Yang, Goar Smbatayan, Unnati Hemant Shah, Jae Ho Lo, Joshua Millstein, Francesca Battaglin, Pooja Mittal, Lesly Torres Gonzalez, Wu Zhang, Jean Chen Shih, Heinz Josef Lenz. MAO A, MAO B inhibitors and NMI for colon cancer therapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4671.
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Chaurasiya, Narayan, Jianping Zhao, Pankaj Pandey, Robert Doerksen, Ilias Muhammad, and Babu Tekwani. "Selective Inhibition of Human Monoamine Oxidase B by Acacetin 7-Methyl Ether Isolated from Turnera diffusa (Damiana)." Molecules 24, no. 4 (February 23, 2019): 810. http://dx.doi.org/10.3390/molecules24040810.
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The investigation of the constituents that were isolated from Turnera diffusa (damiana) for their inhibitory activities against recombinant human monoamine oxidases (MAO-A and MAO-B) in vitro identified acacetin 7-methyl ether as a potent selective inhibitor of MAO-B (IC50 = 198 nM). Acacetin 7-methyl ether (also known as 5-hydroxy-4′, 7-dimethoxyflavone) is a naturally occurring flavone that is present in many plants and vegetables. Acacetin 7-methyl ether was four-fold less potent as an inhibitor of MAO-B when compared to acacetin (IC50 = 50 nM). However, acacetin 7-methyl ether was >500-fold selective against MAO-B over MAO-A as compared to only two-fold selectivity shown by acacetin. Even though the IC50 for inhibition of MAO-B by acacetin 7-methyl ether was ~four-fold higher than that of the standard drug deprenyl (i.e., SelegilineTM or ZelaparTM, a selective MAO-B inhibitor), acacetin 7-methyl ether’s selectivity for MAO-B over MAO-A inhibition was greater than that of deprenyl (>500- vs. 450-fold). The binding of acacetin 7-methyl ether to MAO-B was reversible and time-independent, as revealed by enzyme-inhibitor complex equilibrium dialysis assays. The investigation on the enzyme inhibition-kinetics analysis with varying concentrations of acacetin 7-methyl ether and the substrate (kynuramine) suggested a competitive mechanism of inhibition of MAO-B by acacetin 7-methyl ether with Ki value of 45 nM. The docking scores and binding-free energies of acacetin 7-methyl ether to the X-ray crystal structures of MAO-A and MAO-B confirmed the selectivity of binding of this molecule to MAO-B over MAO-A. In addition, molecular dynamics results also revealed that acacetin 7-methyl ether formed a stable and strong complex with MAO-B. The selective inhibition of MAO-B suggests further investigations on acacetin 7-methyl as a potential new drug lead for the treatment of neurodegenerative disorders, including Parkinson’s disease.
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Durdu, Salih. "Characterization, Bioactivity and Antibacterial Properties of Copper-Based TiO2 Bioceramic Coatings Fabricated on Titanium." Coatings 9, no. 1 (December 20, 2018): 1. http://dx.doi.org/10.3390/coatings9010001.
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The bioactive and anti-bacterial Cu-based bioceramic TiO2 coatings have been fabricated on cp-Ti (Grade 2) by two-steps. These two-steps combine micro-arc oxidation (MAO) and physical vapor deposition–thermal evaporation (PVD-TE) techniques for dental implant applications. As a first step, all surfaces of cp-Ti substrate were coated by MAO technique in an alkaline electrolyte, consisting of Na3PO4 and KOH in de-ionized water. Then, as a second step, a copper (Cu) nano-layer with 5 nm thickness was deposited on the MAO by PVD-TE technique. Phase structure, morphology, elemental amounts, thickness, roughness and wettability of the MAO and Cu-based MAO coating surfaces were characterized by XRD (powder- and TF-XRD), SEM, EDS, eddy current device, surface profilometer and contact angle goniometer, respectively. The powder- and TF-XRD spectral analyses showed that Ti, TiO2, anatase-TiO2 and rutile-TiO2 existed on the MAO and Cu-based MAO coatings’ surfaces. All coatings’ surfaces were porous and rough, owing to the presence of micro sparks through MAO. Furthermore, the surface morphology of Cu-based MAO was not changed. Also, the Cu-based MAO coating has more hydrophilic properties than the MAO coating. In vitro bioactivity and in vitro antibacterial properties of the coatings have been investigated by immersion in simulated body fluid (SBF) at 36.5 °C for 28 days and bacterial adhesion for gram-positive (S. aureus) and gram-negative (E. coli) bacteria, respectively. The apatite layer was formed on the MAO and Cu-based MAO surfaces at post-immersion in SBF and therefore, the bioactivity of Cu-based MAO surface was increased to the MAO surface. Also, for S. aureus and E. coli, the antibacterial properties of Cu-based MAO coatings were significantly improved compared to one of the uncoated MAO surfaces. These results suggested that Cu-based MAO coatings on cp-Ti could be a promising candidate for biomedical dental implant applications.
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Yao, Yuhong, Wei Yang, Dongjie Liu, Wei Gao, and Jian Chen. "Preparation and Corrosion Behavior in Marine Environment of MAO Coatings on Magnesium Alloy." Materials 13, no. 2 (January 12, 2020): 345. http://dx.doi.org/10.3390/ma13020345.
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To improve the corrosion performance of magnesium alloys in the marine environment, the MAO, MAO–Cu2CO3(OH)2·H2O and MAO–Cu2P2O7 ceramic coatings were deposited on AZ91D magnesium alloys in basic electrolyte and the discoloration mechanism of the Cu-doped MAO coatings and the corrosion behavior of the three MAO coatings in the artificial seawater solution were investigated by SEM, EDS and XPS. The results indicated that the formation and discoloration mechanism of the brown MAO ceramic coatings were attributable to the formation of Cu2O in the coatings. Though the three MAO coatings had a certain protective effect against the corrosion of AZ91D substrate in the artificial seawater, the distinctive stratification phenomenon was found on the MAO–Cu2P2O7 coated sample and the corrosion model of the MAO–Cu2P2O7 coatings in the immersion experiment was established. Therefore, the brown Cu-doped MAO coatings were speculated to significantly reduce the risk of the magnesium parts in marine environments.
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Cao, Huihui, Wangtu Huo, Shufang Ma, Yusheng Zhang, and Lian Zhou. "Microstructure and Corrosion Behavior of Composite Coating on Pure Mg Acquired by Sliding Friction Treatment and Micro-Arc Oxidation." Materials 11, no. 7 (July 18, 2018): 1232. http://dx.doi.org/10.3390/ma11071232.
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For the purpose of detecting the influence of grain structure of a Mg matrix on the microstructure and corrosion resistance of micro-arc oxidation (MAO) coating, prior to MAO processing, sliding friction treatment (SFT) was adopted to generate a fine-grained (FG) layer on coarse-grained (CG) pure Mg surface. It showed that the FG layer had superior corrosion resistance, as compared to the CG matrix, owing to the grain refinement; furthermore, it successfully survived after MAO treatment. Thus, an excellent FG-MAO coating was gained by combining SFT and MAO. The surface morphology and element composition of FG-MAO and CG-MAO samples did not show significant changes. However, the FG layer favorably facilitated the formation of an excellent MAO coating, which possessed a superior bonding property and greater thickness. Consequently, the modified FG-MAO sample possessed enhanced corrosion resistance, since a lower hydrogen evolution rate, a larger impedance modulus and a lower corrosion current were observed on the FG-MAO sample.
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Yu, Jie, Shi Chun Di, Yan Wang, Peng Xiang Lv, and Jun Jie Yang. "Densification Behavior and Microstructure Evolution of Laser Surface Melting Processed Silicon-Containing Micro Arc Oxidation Coating." Advanced Materials Research 941-944 (June 2014): 1650–53. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1650.
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The present work investigated the effect of laser surface melting (LSM) process on micro arc oxidation (MAO) coating prepared in silicate electrolytes (Si-MAO) and aluminate electrolytes (Al-MAO). Plasma intensity of laser spots, element content and phase constituents of coatings were analyzed. During LSM remelting process, the formation of heat sources and micro molten pools on the surface of MAO coating were discussed. The results showed that the moderate plasma was formed more easily on the Si-MAO than Al-MAO coating, owing to the temperature threshold of melting oxide layer was decreased for silicon-containing MAO coating during LSM treatment. Besides, the Si-MAO coating of laser-treated had low porosity and smooth surface.
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Chaurasiya, Narayan D., Jacob Midiwo, Pankaj Pandey, Regina N. Bwire, Robert J. Doerksen, Ilias Muhammad, and Babu L. Tekwani. "Selective Interactions of O-Methylated Flavonoid Natural Products with Human Monoamine Oxidase-A and -B." Molecules 25, no. 22 (November 17, 2020): 5358. http://dx.doi.org/10.3390/molecules25225358.
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A set of structurally related O-methylated flavonoid natural products isolated from Senecio roseiflorus (1), Polygonum senegalense (2 and 3), Bhaphia macrocalyx (4), Gardenia ternifolia (5), and Psiadia punctulata (6) plant species were characterized for their interaction with human monoamine oxidases (MAO-A and -B) in vitro. Compounds 1, 2, and 5 showed selective inhibition of MAO-A, while 4 and 6 showed selective inhibition of MAO-B. Compound 3 showed ~2-fold selectivity towards inhibition of MAO-A. Binding of compounds 1–3 and 5 with MAO-A, and compounds 3 and 6 with MAO-B was reversible and not time-independent. The analysis of enzyme-inhibition kinetics suggested a reversible-competitive mechanism for inhibition of MAO-A by 1 and 3, while a partially-reversible mixed-type inhibition by 5. Similarly, enzyme inhibition-kinetics analysis with compounds 3, 4, and 6, suggested a competitive reversible inhibition of MAO-B. The molecular docking study suggested that 1 selectively interacts with the active-site of human MAO-A near N5 of FAD. The calculated binding free energies of the O-methylated flavonoids (1 and 4–6) and chalcones (2 and 3) to MAO-A matched closely with the trend in the experimental IC50′s. Analysis of the binding free-energies suggested better interaction of 4 and 6 with MAO-B than with MAO-A. The natural O-methylated flavonoid (1) with highly potent inhibition (IC50 33 nM; Ki 37.9 nM) and >292 fold selectivity against human MAO-A (vs. MAO-B) provides a new drug lead for the treatment of neurological disorders.
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Alkhawaldeh, Aseel, and Sanaa Bardaweel. "Molecular Investigation of the Antitumor Effects of Monoamine Oxidase Inhibitors in Breast Cancer Cells." BioMed Research International 2023 (October 5, 2023): 1–12. http://dx.doi.org/10.1155/2023/2592691.
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The catalytic activity of monoamine oxidase A (MAO-A) has been linked to tumorigenesis due to the production of reactive oxygen species (ROS) and the resulting oxidative stress. MAO-A inhibition revealed a beneficial role in prostate and lung cancer treatment. This study is aimed at evaluating the effect of different monoamine oxidase A inhibitors (MAO-AIs) on the proliferation and progression of breast cancer cell lines. The cell viability assay was used to evaluate the antiproliferative and combined effects of MAO-AIs. Cell migration was evaluated using wound healing, invasion, and colony formation assays. The underlying mechanism of cell death was studied using flow cytometry. The real-time polymerase chain reaction was used to determine the relative gene expression. Finally, MAO-A activity in breast cancer cells was evaluated using an MAO-A activity assay. According to the results, the examined MAO-AIs significantly inhibited the proliferation of breast cancer cells in a dose-dependent manner. In breast cancer cells, the combination of anticancer drugs (doxorubicin or raloxifene) with MAO-AIs resulted in a synergistic effect. MAO-AIs significantly reduced wound closure and invasion ability in breast cancer cells. Also, MAO-AIs reduced the colony count and size of breast cancer cells. MAO-AIs resulted in significant proapoptotic activity in breast cancer cells. Finally, the MAO-AIs suppressed MAO-A, Bcl-2, and VEGF gene expressions in breast cancer cells relative to untreated cells. This study provides solid evidence supporting the anticancer effect of MAO-A inhibitors in breast cancer cells.
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SHAO, ZHONGCAI, FEIFEI ZHANG, RUIQIANG ZHAO, and XIAOYI SHEN. "PREPARATION OF COMPOSITE COATING ON AZ91D MAGNESIUM ALLOY BY SILICA SOL-MICRO-ARC OXIDATION." Surface Review and Letters 23, no. 04 (June 15, 2016): 1650029. http://dx.doi.org/10.1142/s0218625x16500293.
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Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol–gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO2 gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.
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Huang, CC, HM Li, DH Li, and SY Lin. "The performance of titanium composite coatings obtained through thermal spraying and microarc oxidation." Composites and Advanced Materials 30 (January 1, 2021): 2633366X2097468. http://dx.doi.org/10.1177/2633366x20974686.
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The development of composite coatings essential to improve the wear and corrosion resistances of the materials employed in numerous applications, such as automobile, chemical, medicine, construction, aerospace, and biomedical industries. In this study, we presented a double-layer coating technique, which consisted of a thermal-sprayed titanium (Ti) layer and a micro-arc oxidation (MAO) film on AISI 1020 steel. The effect of the composite coatings (Ti/MAO) on wear and corrosion resistance was investigated. To obtain a coating thickness from 250 µm to 450 µm, the prepared specimens were coated with Ti (99.9% pure) by arc spraying. Then, the Ti/MAO films were deposited on Ti coatings. The current density of MAO was fixed at 35 A/dm2, the voltages were 250, 300, 350, 400, and 450 V, and the duration of the MAO process was 10 min, Measurements of film thickness, microstructure, microhardness, X-ray diffractometry analysis, and scanning electron microscopic observation were performed for determining the characteristics of the composite coatings (Ti/MAO). Potentiodynamic polarization curves were used to compare the corrosion resistance of these composite coatings. A ball-on-disc wear test, using an oscillation friction wear tester, was carried out at room temperature according to the ASTM G99 standard to determine the wear resistance. Among all the specimens, Ti/MAO (400 V) had the greatest hardness, lowest friction coefficient, least weight loss, and longest sliding distance. The sliding distance of Ti/MAO (400 V) was about 1.7 times higher than those of Ti. The open-circuit potential of Ti/MAO (400 V) was about 1.7 times better than those of Ti. The corrosion currents of Ti/MAO (250 V) and Ti/MAO (400 V) were decreased by MAO about 95% and 92%, respectively. Although the corrosion current of Ti/MAO (400 V) was higher than that of Ti/MAO (250 V), Ti/MAO (400 V) had better effects in other tests. According to the results, Ti/MAO (400 V) presented the best performance among all the specimens and provided improved protection to both Ti and substrate.
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Billett, E. E., and R. J. Mayer. "Monoclonal antibodies to monoamine oxidase B and another mitochondrial protein from human liver." Biochemical Journal 235, no. 1 (April 1, 1986): 257–63. http://dx.doi.org/10.1042/bj2350257.
Full textAbstract:
A monoclonal antibody has been generated to human liver monoamine oxidase (MAO) B by fusion of mouse myeloma cells with spleen cells from a mouse immunized with a mixture of semi-purified MAO A and MAO B. The antibody, 3F12/G10, an immunoglobulin G1, reacts with its antigen in cryostat sections of human liver, showing an intracellular particulate distribution as demonstrated by immunoperoxidase staining. The antibody indirectly precipitates [3H]pargyline-labelled human MAO B both from liver and platelet extracts but fails to precipitate MAO A from liver extracts. The antibody does not recognise rat liver MAO B, showing that the determinant is not universally expressed on MAO B. The antibody has no effect on the catalytic activity of MAO B. Other monoclonal antibodies were generated but they are directed to a protein with a subunit Mr of 54 000, a contaminant of the MAO preparation. One of these antibodies, A8/C2, an IgG2a, reacts with the same protein in both rat and human liver extracts.
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Chaurasiya, Narayan D., Francisco León, Yuanqing Ding, Isabel Gómez-Betancur, Dora Benjumea, Larry A. Walker, Stephen J. Cutler, and Babu L. Tekwani. "Interactions of Desmethoxyyangonin, a Secondary Metabolite fromRenealmia alpinia, with Human Monoamine Oxidase-A and Oxidase-B." Evidence-Based Complementary and Alternative Medicine 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4018724.
Full textAbstract:
Renealmia alpinia(Zingiberaceae), a medicinal plant of tropical rainforests, is used to treat snakebites and other injuries and also as a febrifuge, analgesic, antiemetic, antiulcer, and anticonvulsant. The dichloromethane extract ofR. alpinialeaves showed potent inhibition of human monoamine oxidases- (MAOs-) A and B. Phytochemical studies yielded six known compounds, including pinostrobin1, 4′-methyl ether sakuranetin2, sakuranetin3, pinostrobin chalcone4, yashabushidiol A5, and desmethoxyyangonin6. Compound6displayed about 30-fold higher affinity for MAO-B than MAO-A, with Ki values of 31 and 922 nM, respectively. Kinetic analysis of inhibition and equilibrium-dialysis dissociation assay of the enzyme-inhibitor complex showed reversible binding of desmethoxyyangonin6with MAO-A and MAO-B. The binding interactions of compound6in the active site of the MAO-A and MAO-B isoenzymes, investigated through molecular modeling algorithms, confirmed preferential binding of desmethoxyyangonin6with MAO-B compared to MAO-A. Selective reversible inhibitors of MAO-B, like desmethoxyyangonin6,may have important therapeutic significance for the treatment of neurodegenerative disorders, such as Parkinson’s disease and Alzheimer’s disease.
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Thorpe, L. W., K. N. Westlund, L. M. Kochersperger, C. W. Abell, and R. M. Denney. "Immunocytochemical localization of monoamine oxidases A and B in human peripheral tissues and brain." Journal of Histochemistry & Cytochemistry 35, no. 1 (January 1987): 23–32. http://dx.doi.org/10.1177/35.1.3025289.
Full textAbstract:
Monoamine oxidases (MAO; EC 1.4.3.4.) A and B occur in the outer mitochondrial membrane and oxidize a number of important biogenic and xenobiotic amines. Monoclonal antibodies specific for human MAO A or B and immunocytochemical techniques were used to visualize the respective enzymes in human placenta, platelets, lymphocytes, liver, brain, and a human hepatoma cell line. MAO A was observed in the syncytiotrophoblast layer of term placenta, liver, and a subset of neurons in brain, but was not observed in platelets or lymphocytes, which are known to lack type A enzyme. MAO B was observed in platelets, lymphocytes, and liver, but not in placenta, which contains little or no MAO B. MAO B was also observed in a subset of neurons in the brain that was distinct from that which contained MAO A. MAO A and MAO B were also observed in some glia. Unlike most tissues examined, liver cells appeared to contain both forms of the enzyme. These studies show that MAO A and MAO B can be specifically visualized by immunocytochemical means in a variety of human cells and tissues and can provide a graphic demonstration of the high degree of cell specificity of expression of the two forms of the enzyme.
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Lighezan, Rodica, Adrian Sturza, Oana M. Duicu, Raluca A. Ceausu, Adrian Vaduva, Marian Gaspar, Horea Feier, et al. "Monoamine oxidase inhibition improves vascular function in mammary arteries from nondiabetic and diabetic patients with coronary heart disease." Canadian Journal of Physiology and Pharmacology 94, no. 10 (October 2016): 1040–47. http://dx.doi.org/10.1139/cjpp-2015-0580.
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Monoamine oxidases (MAOs) are mitochondrial enzymes with 2 isoforms that have emerged as important contributors to cardiovascular oxidative stress via the constant generation of hydrogen peroxide. The present study was purported to assess whether MAO-derived H2O2 contributes to the endothelial dysfunction in mammary arteries harvested from coronary heart disease patients with and without diabetes mellitus subjected to coronary artery bypass grafting. To this aim, the effects of MAO inhibition on vascular contractility to phenylephrine and endothelial-dependent relaxation (EDR) in response to acetylcholine were studied in vascular segments. Clorgyline (irreversible MAO-A inhibitor), selegiline (irreversible MAO-B inhibitor), and moclobemide (reversible MAO-A inhibitor) were applied in the organ bath (10 μmol/L). MAO expression was assessed by immunohistochemistry. We found a constant impairment of EDR that has been significantly attenuated in the presence of the MAO-A and MAO-B inhibitors in both groups of coronary heart disease patients. MAO-B was the dominant isoform in all human diseased vessels. In conclusion, in vitro inhibition of MAO significantly improved EDR in human mammary arteries, regardless of the presence of diabetes. These data suggest that MAO inhibitors might be useful in restoring endothelial response in clinical conditions associated with increased oxidative stress, such as coronary artery disease and diabetes.
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Chaurasiya, Narayan D., Haining Liu, Robert J. Doerksen, N. P. Dhammika Nanayakkara, Larry A. Walker, and Babu L. Tekwani. "Enantioselective Interactions of Anti-Infective 8-Aminoquinoline Therapeutics with Human Monoamine Oxidases A and B." Pharmaceuticals 14, no. 5 (April 22, 2021): 398. http://dx.doi.org/10.3390/ph14050398.
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8-Aminoquinolines (8-AQs) are an important class of anti-infective therapeutics. The monoamine oxidases (MAOs) play a key role in metabolism of 8-AQs. A major role for MAO-A in metabolism of primaquine (PQ), the prototypical 8-AQ antimalarial, has been demonstrated. These investigations were further extended to characterize the enantioselective interactions of PQ and NPC1161 (8-[(4-amino-1-methylbutyl) amino]-5-[3, 4-dichlorophenoxy]-6-methoxy-4-methylquinoline) with human MAO-A and -B. NPC1161B, the (R)-(−) enantiomer with outstanding potential for malaria radical cure, treatment of visceral leishmaniasis and pneumocystis pneumonia infections is poised for clinical development. PQ showed moderate inhibition of human MAO-A and -B. Racemic PQ and (R)-(−)-PQ both showed marginally greater (1.2- and 1.6-fold, respectively) inhibition of MAO-A as compared to MAO-B. However, (S)-(+)-PQ showed a reverse selectivity with greater inhibition of MAO-B than MAO-A. Racemic NPC1161 was a strong inhibitor of MAOs with 3.7-fold selectivity against MAO-B compared to MAO-A. The (S)-(+) enantiomer (NPC1161A) was a better inhibitor of MAO-A and -B compared to the (R)-(−) enantiomer (NPC1161B), with more than 10-fold selectivity for inhibition of MAO-B over MAO-A. The enantioselective interaction of NPC1161 and strong binding of NPC1161A with MAO-B was further confirmed by enzyme-inhibitor binding and computational docking analyses. Differential interactions of PQ and NPC1161 enantiomers with human MAOs may contribute to the enantioselective pharmacodynamics and toxicity of anti-infective 8-AQs therapeutics.
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WHITFIELD, J. B., D. PANG, K. K. BUCHOLZ, P. A. F. MADDEN, A. C. HEATH, D. J. STATHAM, and N. G. MARTIN. "Monoamine oxidase: associations with alcohol dependence, smoking and other measures of psychopathology." Psychological Medicine 30, no. 2 (March 2000): 443–54. http://dx.doi.org/10.1017/s0033291799001798.
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Background. Many reports have appeared on associations between platelet monoamine oxidase (MAO) activity and susceptibility to psychiatric conditions; principally alcohol dependence but also conduct disorder, other drug use and depression. Recently, it has become apparent that MAO activity is inhibited by some component of cigarette smoke, and smokers have low platelet MAO activity. Since the prevalence of smoking is higher in many of the conditions in which MAO has been implicated, the MAO susceptibility associations may be partly, or entirely, false.Methods. We have measured platelet MAO in 1551 subjects, recruited from the Australian NHMRC Twin Registry, who have provided information on alcohol use and dependence, smoking, conduct disorder, depression, attempted suicide, panic disorder and social phobia.Results. Current smoking reduced platelet MAO activity in a significant and dose-related manner, with no evidence of lower MAO in ex-smokers or in non-smoking subjects with co-twins who smoked. Alcohol use and lifetime DSM-III-R alcohol dependence history were not associated with MAO activity when smoking was taken into account. Depression, panic disorder and social phobia showed no significant associations with platelet MAO activity. Subjects with a history of serious attempts at suicide had low platelet MAO activity; but although the difference from controls was as great as the reduction associated with smoking it was not significant after correction for smoking effects.Conclusions. Although synaptic MAO activity undoubtedly plays a role in psychopathology, the concept that platelet MAO activity is a direct genetic marker of vulnerability to alcohol dependence cannot be sustained.
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Sa’adah, N. L., M. F. B. Darmawan, M. B. Dewantari, K. U. Haq, and H. Suwito. "EXPLORATION OF PYRAZOLINE AND AMINO CHALCONE DERIVATIVES AS MONOAMINE OXIDASE INHIBITORS: AN IN-SILICO APPROACH." RASAYAN Journal of Chemistry 16, no. 02 (2023): 588–95. http://dx.doi.org/10.31788/rjc.2023.1628184.
Full textAbstract:
Monoamine oxidase (MAO) is an enzyme involved in neurotransmitter monoamine metabolism through an oxidative deamination reaction that produces a nerve-damaging substance, H2O2. Two isoforms of MAO that are MAO-A, and MAO-B, are known by their specific substrates, serotonin, and dopamine, respectively. Overexpression of MAO-A causes depression and anxiety disorder, whereas MAO-B causes neurodegenerative disorders such as Parkinson’s and Alzheimer’s. Infections and diseases caused by the activity of these two enzymes are known to affect millions of people worldwide every year. Various drugs for both disorders are available on the market. However, side effects such as dizziness, sore throat, insomnia, obesity, and heart disorder are registered. Therefore, developing new compounds acting as MAO inhibitors with lower side effects but higher selectivity than available drugs is in need. Pyrazolines and amino chalcone derivatives are well known to exhibit inhibition of MAO activity and used as research objects. Virtual screening of molecular docking using DOCK6 of six compounds of each pyrazoline (1a-f) (both R and S configuration) and amino chalcone (2a-f) was conducted to study their inhibition activity to MAO-A (PDB: 2Z5X) and MAO-B (PDB: 6FW0) and selectivity based on comparison of grid score value of Harmin as control positive for MAO-A and E92 ligand for MAO-B. The results showed that the most potent compound as a selective inhibitor of MAO is (R)-3-(4-aminophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carboxamide of pyrazoline derivative and (1- (4-cinnamoyl phenyl) thiourea) of amino chalcone derivative.
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Zhang, Zhenxian, Hiroki Hamada, and Phillip M. Gerk. "Selectivity of Dietary Phenolics for Inhibition of Human Monoamine Oxidases A and B." BioMed Research International 2019 (January 23, 2019): 1–12. http://dx.doi.org/10.1155/2019/8361858.
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Monoamine oxidases (MAOs) regulate local levels of neurotransmitters such as dopamine, norepinephrine, and serotonin and thus have been targeted by drugs for the treatment of certain CNS disorders. However, recent studies have shown that these enzymes are upregulated with age in nervous and cardiac tissues and may be involved in degeneration of these tissues, since their metabolic mechanism releases hydrogen peroxide leading to oxidative stress. Thus, targeting these enzymes may be a potential anti-aging strategy. The purpose of this study was to compare the MAO inhibition and selectivity of selected dietary phenolic compounds, using a previously validated assay that would avoid interference from the compounds. Kynuramine metabolism by human recombinant MAO-A and MAO-B leads to formation of 4-hydroxyquinoline, with Vmax values of 10.2±0.2 and 7.35±0.69 nmol/mg/min, respectively, and Km values of 23.1±0.8 μM and 18.0±2.3 μM, respectively. For oral dosing and interactions with the gastrointestinal tract, curcumin, guaiacol, isoeugenol, pterostilbene, resveratrol, and zingerone were tested at their highest expected luminal concentrations from an oral dose. Each of these significantly inhibited both enzymes except for zingerone, which only inhibited MAO-A. The IC50 values were determined, and selectivity indices (MAO-A/MAO-B IC50 ratios) were calculated. Resveratrol and isoeugenol were selective for MAO-A, with IC50 values of 0.313±0.008 and 3.72±0.20 μM and selectivity indices of 50.5 and 27.4, respectively. Pterostilbene was selective for MAO-B, with IC50 of 0.138±0.013 μM and selectivity index of 0.0103. The inhibition of resveratrol (MAO-A) and pterostilbene (MAO-B) was consistent with competitive time-independent mechanisms. Resveratrol 4’-glucoside was the only compound which inhibited MAO-A, but itself, resveratrol 3-glucoside, and pterostilbene 4’-glucoside failed to inhibit MAO-B. Additional studies are needed to establish the effects of these compounds on MAO-A and/or MAO-B in humans.
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Oh, Jong Min, Yaren Nur Zenni, Zeynep Özdemir, Sunil Kumar, Semanur Kılıç, Mevlüt Akdağ, Azime Berna Özçelik, Hoon Kim, and Bijo Mathew. "Inhibition of Monoamine Oxidases by Pyridazinobenzylpiperidine Derivatives." Molecules 29, no. 13 (June 28, 2024): 3097. http://dx.doi.org/10.3390/molecules29133097.
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Monoamine oxidase inhibitors (MAOIs) have been crucial in the search for anti-neurodegenerative medications and continued to be a vital source of molecular and mechanistic diversity. Therefore, the search for selective MAOIs is one of the main areas of current drug development. To increase the effectiveness and safety of treating Parkinson’s disease, new scaffolds for reversible MAO-B inhibitors are being developed. A total of 24 pyridazinobenzylpiperidine derivatives were synthesized and evaluated for MAO. Most of the compounds showed a higher inhibition of MAO-B than of MAO-A. Compound S5 most potently inhibited MAO-B with an IC50 value of 0.203 μM, followed by S16 (IC50 = 0.979 μM). In contrast, all compounds showed weak MAO-A inhibition. Among them, S15 most potently inhibited MAO-A with an IC50 value of 3.691 μM, followed by S5 (IC50 = 3.857 μM). Compound S5 had the highest selectivity index (SI) value of 19.04 for MAO-B compared with MAO-A. Compound S5 (3-Cl) showed greater MAO-B inhibition than the other derivatives with substituents of -Cl > -OCH3 > -F > -CN > -CH3 > -Br at the 3-position. However, the 2- and 4-position showed low MAO-B inhibition, except S16 (2-CN). In addition, compounds containing two or more substituents exhibited low MAO-B inhibition. In the kinetic study, the Ki values of S5 and S16 for MAO-B were 0.155 ± 0.050 and 0.721 ± 0.074 μM, respectively, with competitive reversible-type inhibition. Additionally, in the PAMPA, both lead compounds demonstrated blood–brain barrier penetration. Furthermore, stability was demonstrated by the 2V5Z-S5 complex by pi–pi stacking with Tyr398 and Tyr326. These results suggest that S5 and S16 are potent, reversible, selective MAO-B inhibitors that can be used as potential agents for the treatment of neurological disorders.
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Yang, Kaidi, and Rainer Glaser. "Transition Metal-Catalyzed and MAO-Assisted Olefin Polymerization; Cyclic Isomers of Sinn’s Dimer Are Excellent Ligands in Iron Complexes and Great Methylating Reagents." Catalysts 12, no. 3 (March 9, 2022): 312. http://dx.doi.org/10.3390/catal12030312.
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Methylaluminoxane (MAO) is the most commonly used co-catalyst for transition metal-catalyzed olefin polymerization, but the structures of MAO species and their catalytic functions remain topics of intensive study. We are interested in MAO-assisted polymerization with catalysts L(R2)FeCl2 (L = tridentate pyridine-2,6-diyldimethanimine; imine-R = Me, Ph). It is our hypothesis that the MAO species is not merely enabling Fe–Me bond formation but functions as an integral part of the active catalyst, a MAO adduct of the Fe-precatalyst [L(R2)FeCl]+. In this paper, we explored the possible structures of acyclic and cyclic MAO species and their complexation with pre-catalysts [L(R2)FeCl]+ using quantum chemical approaches (MP2 and DFT). We report absolute and relative oxophilicities associated with the Fe ← O(MAO) adduct formation and provide compelling evidence that oxygen of an acyclic MAO species (i.e., O(AlMe2)2, 4) cannot compete with the O-donor in cyclic MAO species (i.e., (MeAlO)2, 7; MeAl(OAlMe2)2, cyclic 5). Significantly, our work demonstrates that intramolecular O → Al dative bonding results in cyclic isomers of MAO species (i.e., cyclic 5) with high oxophilicities. The stabilities of the [L(R2)FeClax(MAO)eq]+ species demonstrate that 5 provides for the ligating benefits of the cyclic MAO species 4 without the thermodynamically costly elimination of TMA. Mechanistic implications are discussed for the involvement of such Fe–O–Al bridged catalyst in olefin polymerization.
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Cabanillas, A. M., A. M. Masini-Repiso, M. E. Costamagna, C. Pellizas, and A. H. Coleoni. "Thyroid iodide transport is reduced by administration of monoamine oxidase A inhibitors to rats." Journal of Endocrinology 143, no. 2 (November 1994): 303–8. http://dx.doi.org/10.1677/joe.0.1430303.
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Abstract The present work was addressed to study a possible relationship between monoamine oxidase (MAO) and the thyroid iodide transport mechanism. Normal rats treated with clorgyline (a selective MAO-A inhibitor) or tranylcypromine (a non-selective MAO inhibitor) showed a significantly diminished thyroid MAO activity, while deprenyl and pargyline (MAO-B inhibitors) did not modify the thyroidal enzyme activity with respect to the control group. Under these conditions, in vivo iodide transport was reduced both by clorgyline and tranylcypromine administration whereas it remained unchanged after treatment with MAO-B inhibitors. The effect of MAO inhibitors on thyroid MAO activity and in vivo iodide transport was also evaluated in rats treated with exogenous thyrotrophin (TSH) after endogenous TSH secretion blockade produced by T4 administration. In this condition, thyroid MAO activity was significantly lowered by clorgyline and was not modified by deprenyl. In contrast to the results observed in normal rats, in vivo iodide transport in TSH-treated rats remained unaltered after treatment either with clorgyline or deprenyl. MAO activity evaluated in bovine thyroid follicles in primary culture was highly sensitive to low concentrations of clorgyline (<10 nmol/l) and relatively insensitive to deprenyl, a finding that indicates a predominance of the MAO-A isoform in the follicular cells in culture. When clorgyline (0·1 and 1 μmol/l) or deprenyl (1 μmol/l) were added to the culture medium, no modifications in the active transport of iodide were observed. These results indicate the absence of a direct linkage between thyroid MAO activity and the active iodide transport. MAO inhibitors (particularly MAO-A inhibitors) do not appear to be responsible for an in vivo diminished thyroid iodide uptake through a direct action on the iodide transport mechanism. An indirect effect of MAO-A inhibitors on thyroid iodide transport mediated by the accumulation of monoamines in neuroendocrine areas involved in TSH regulation is suggested. Journal of Endocrinology (1994) 143, 303–308
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Bardaweel, Sanaa, Reem Aljanabi, Dima Sabbah, and Kamal Sweidan. "Design, Synthesis, and Biological Evaluation of Novel MAO-A Inhibitors Targeting Lung Cancer." Molecules 27, no. 9 (April 30, 2022): 2887. http://dx.doi.org/10.3390/molecules27092887.
Full textAbstract:
Lung cancer is one of the most common causes of cancer-related deaths worldwide. Monoamine Oxidase-A (MAO-A) enzyme mediates the production of reactive oxygen species (ROS) that trigger DNA damage and oxidative injury of cells resulting in tumor initiation and progression. Available MAO-A inhibitors are used as antidepressants, however, their role as anticancer agents is still under investigation. Ligand- and structure-based drug design approaches guided the discovery and development of novel MAO-A inhibitors. A series of 1H indole-2-carboxamide derivatives was prepared and characterized using 1H-NMR, 13C-NMR, and IR. The antiproliferative effects of MAO-A inhibitors were evaluated using the cell viability assay (MTT), and MAO-A activity was evaluated using MAO-A activity assay. The presumed inhibitors significantly inhibited the growth of lung cell lines in a dose- and time dependent manner. The half maximal inhibitory concentration (IC50) values of MAO-A inhibitors (S1, S2, S4, S7, and S10) were 33.37, 146.1, 208.99, 307.7, and 147.2 µM, respectively, in A549. Glide docking against MAO-A showed that the derivatives accommodate MAO-A binding cleft and engage with key binding residues. MAO-A inhibitors provide significant and consistent evidence on MAO-A activity in lung cancer and present a potential target for the development of new chemotherapeutic agents.
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Çeçen, Muhammed, Jong Min Oh, Zeynep Özdemir, Saliha Ebru Büyüktuncel, Mehtap Uysal, Mohamed A. Abdelgawad, Arafa Musa, et al. "Design, Synthesis, and Biological Evaluation of Pyridazinones Containing the (2-Fluorophenyl) Piperazine Moiety as Selective MAO-B Inhibitors." Molecules 25, no. 22 (November 17, 2020): 5371. http://dx.doi.org/10.3390/molecules25225371.
Full textAbstract:
Twelve pyridazinones (T1–T12) containing the (2-fluorophenyl) piperazine moiety were designed, synthesized, and evaluated for monoamine oxidase (MAO) -A and -B inhibitory activities. T6 was found to be the most potent MAO-B inhibitor with an IC50 value of 0.013 µM, followed by T3 (IC50 = 0.039 µM). Inhibitory potency for MAO-B was more enhanced by meta bromo substitution (T6) than by para bromo substitution (T7). For para substitution, inhibitory potencies for MAO-B were as follows: -Cl (T3) > -N(CH3)2 (T12) > -OCH3 (T9) > Br (T7) > F (T5) > -CH3 (T11) > -H (T1). T6 and T3 efficiently inhibited MAO-A with IC50 values of 1.57 and 4.19 µM and had the highest selectivity indices (SIs) for MAO-B (120.8 and 107.4, respectively). T3 and T6 were found to be reversible and competitive inhibitors of MAO-B with Ki values of 0.014 and 0.0071, respectively. Moreover, T6 was less toxic to healthy fibroblast cells (L929) than T3. Molecular docking simulations with MAO binding sites returned higher docking scores for T6 and T3 with MAO-B than with MAO-A. These results suggest that T3 and T6 are selective, reversible, and competitive inhibitors of MAO-B and should be considered lead candidates for the treatment of neurodegenerative disorders like Alzheimer’s disease.
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Zarmouh, Najla O., Samia S. Messeha, Nelly Mateeva, Madhavi Gangapuram, Kacy Flowers, Suresh V. K. Eyunni, Wang Zhang, Kinfe K. Redda, and Karam F. A. Soliman. "The Antiproliferative Effects of Flavonoid MAO Inhibitors on Prostate Cancer Cells." Molecules 25, no. 9 (May 11, 2020): 2257. http://dx.doi.org/10.3390/molecules25092257.
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Prostate cancer (PCa) patients commonly experience clinical depression. Recent reports indicated that monoamine oxidase-A (MAO-A) levels elevate in PCa, and antidepressant MAO-Is show anti-PCa properties. In this work, we aimed to find potential drugs for PCa patients suffering from depression by establishing novel anti-PCa reversible monoamine oxidase-A inhibitors (MAO-AIs/RIMA); with an endeavor to understand their mechanism of action. In this investigation, twenty synthesized flavonoid derivatives, defined as KKR compounds were screened for their inhibitory potentials against human MAO-A and MAO-B isozymes. Meanwhile, the cytotoxic and antiproliferative effects were determined in three human PCa cell lines. MAO-A-kinetics, molecular docking, SAR, cell morphology, and cell migration were investigated for the most potent compounds. The screened KKRs inhibited MAO-A more potently than MAO-B, and non-toxically inhibited LNCaP cell proliferation more than the DU145 and PC3 cell lines, respectively. The results showed that the three top MAO-AI KKRs compounds (KKR11, KKR20, and KKR7 (IC50s 0.02–16 μM) overlapped with the top six antiproliferative KKRs against LNCaP (IC50s ~9.4 μM). While KKR21 (MAO-AI) and KKR2A (MAO-I) were ineffective against the PCa cells. Furthermore, KKR21 and KKR11 inhibited MAO-A competitively (Kis ≤ 7.4 nM). Molecular docking of the two compounds predicted shared hydrophobic and distinctive hydrophilic interactions—between the KKR molecule and MAO-A amino acid residues—to be responsible for their reversibility. The combined results and SAR observations indicated that the presence of specific active groups—such as chlorine and hydroxyl groups—are essential in certain MAO-AIs with anti-PCa effects. Additionally, MAO-A inhibition was found to be associated more with anti-PCa property than MAO-B. Distinctively, KKR11 [(E)-3-(3,4-dichlorophenyl)-1-(2-hydroxy-4,6-dimethoxyphenyl)prop-2-en-1-one] exhibited anti-metastatic effects on the DU145 cell line. The chlorine substitution groups might play vital roles in the KKR11 multiple actions. The obtained results indicated that the flavonoid derivative KKR11 could present a novel candidate for PCa patients with depression, through safe non-selective potent inhibition of MAOs.
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Manni, Maria Elena, Stefania Rigacci, Elisabetta Borchi, Valentina Bargelli, Caterina Miceli, Carla Giordano, Laura Raimondi, and Chiara Nediani. "Monoamine Oxidase Is Overactivated in Left and Right Ventricles from Ischemic Hearts: An Intriguing Therapeutic Target." Oxidative Medicine and Cellular Longevity 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/4375418.
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Growing evidence indicates that reactive oxygen species (ROS) may play a key role in human heart failure (HF). Monoamine oxidase (MAO) is emerging as a major ROS source in several cardiomyopathies. However, little is known about MAO activity in human failing heart and its relationship with redox imbalance. Therefore, we measured MAO activity in the left (LV) and in the right (RV) ventricle of human nonfailing (NF) and in end-stage ischemic (IHD) and nonischemic failing hearts. We found that both MAO isoforms (MAO-A/B) significantly increased in terms of activity and expression levels only in IHD ventricles. Catalase and aldehyde dehydrogenase-2 activities (ALDH-2), both implicated in MAO-catalyzed catecholamine catabolism, were significantly elevated in the failing LV, whereas, in the RV, statistical significance was observed only for ALDH-2. Oxidative stress markers levels were significantly increased only in the failing RV. Actin oxidation was significantly elevated in both failing ventricles and related to MAO-A activity and to functional parameters. These data suggest a close association between MAO-A-dependent ROS generation, actin oxidation, and ventricular dysfunction. This latter finding points to a possible pathogenic role of MAO-A in human myocardial failure supporting the idea that MAO-A could be a new therapeutic target in HF.
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Jia, Zhao, Huiyun Wen, Saipeng Huang, Yane Luo, Juanjuan Gao, Ruijie Wang, Kaikai Wan, and Weiming Xue. "“Click” assembly of novel dual inhibitors of AChE and MAO-B from pyridoxine derivatives for the treatment of Alzheimer’s disease." Heterocyclic Communications 28, no. 1 (January 1, 2022): 18–25. http://dx.doi.org/10.1515/hc-2022-0002.
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Abstract This study fast synthesizes numerous functionalized pyridoxines using click chemistry and assayed in vitro as inhibitors of the acetylcholinesterase (AChE), butyrylcholinesterase, and two monoamine oxidase (MAO) isoforms, MAO-A and MAO-B. Most of the obtained compounds demonstrate good AChE and selective MAO-B inhibitory activities in the micromolar range, especially one compound, called 4k5, exhibits excellent inhibitory performance against AChE (IC50 = 0.0816 ± 0.075 μM) and MAO-B (IC50 = 0.039 ± 0.003 μM). Finally, a docking study is carried out, demonstrating potential binding orientations and interactions of the compounds in terms of the AChE and MAO-B active sites.
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Heger, Jacqueline, Tamara Szabados, Paulin Brosinsky, Péter Bencsik, Péter Ferdinandy, and Rainer Schulz. "Sex Difference in Cardioprotection against Acute Myocardial Infarction in MAO-B Knockout Mice In Vivo." International Journal of Molecular Sciences 24, no. 7 (March 29, 2023): 6443. http://dx.doi.org/10.3390/ijms24076443.
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The cardiomyocyte-specific knockout (KO) of monoamine oxidase (MAO)-B, an enzyme involved in the formation of reactive oxygen species (ROS), reduced myocardial ischemia/reperfusion (I/R) injury in vitro. Because sex hormones have a strong impact on MAO metabolic pathways, we analyzed the myocardial infarct size (IS) following I/R in female and male MAO-B KO mice in vivo. Method and Results: To induce the deletion of MAO-B, MAO-B KO mice (Myh6 Cre+/MAO-Bfl/fl) and wild-type (WT, Cre-negative MAO-Bfl/fl littermates) were fed with tamoxifen for 2 weeks followed by 10 weeks of normal mice chow. Myocardial infarction (assessed by TTC staining and expressed as a percentage of the area at risk as determined by Evans blue staining)) was induced by 45 min coronary occlusion followed by 120 min of reperfusion. Results: The mortality following I/R was higher in male compared to female mice, with the lowest mortality found in MAO-B KO female mice. IS was significantly higher in male WT mice compared to female WT mice. MAO-B KO reduced IS in male mice but had no further impact on IS in female MAO-B KO mice. Interestingly, there was no difference in the plasma estradiol levels among the groups. Conclusion: The cardiomyocyte-specific knockout of MAO-B protects male mice against acute myocardial infarction but had no effect on the infarct size in female mice.
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Veselovsky, A. V., A. S. Ivanov, and A. E. Medvedev. "Computer modelling of monoaminoxidases." Biomeditsinskaya Khimiya 61, no. 2 (2015): 265–71. http://dx.doi.org/10.18097/pbmc20156102265.
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The article summarized results of studies on active site structures of monoamine oxidases (MAO) performed in the Institute of Biomedical Chemistry (Russia) by computer modelling approaches. MAO, catalyzing the reaction of oxidative deamination of major neurotransmitter monoamines, exists in two highly homologous forms, MAO A and MAO B, distinguished by substrate specificity and inhibitor selectivity. The development of approaches for active site modelling of these enzymes (with unknown three-dimensional structures) started from analysis of relationship between the geometrical sizes of rigid indole and isatin derivatives and their inhibitory activity. These studies resulted in molding of the active site structures of MAO A and MAO B. These molds reflect the sizes and shapes of active sites of these enzymes. These mold models have been used for virtual screening of molecular databases for new inhibitors. The models obtained at different stages ofMAO investigations have been compared with recently appeared three-dimensional structures of MAO A and MAO B.
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Arrojo, Manuel, Enrique Baca-Garcia, Maria Mercedes Perez-Rodriguez, Helen Dolengevich-Segal, Mercedes Navio-Acosta, Beatriz Rodriguez-Salgado, and Jeronimo Saiz-Ruiz. "Platelet monoamine oxidase activity in obsessive-compulsive disorder." European Psychiatry 22, no. 8 (November 2007): 525–29. http://dx.doi.org/10.1016/j.eurpsy.2007.06.006.
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AbstractResponse to SSRIs suggests the implication of the serotonergic system in obsessive-compulsive disorder (OCD). However, biological studies on serotonergic function in OCD have yielded contradictory results. Platelet monoamine oxidase (MAO) activity has been proposed as an index of cerebral serotonin activity.The aim of this study was to examine platelet MAO activity in 29 OCD patients and 29 healthy controls matched by age, sex and tobacco use. We also explored the relationship between platelet MAO activity and aggressive obsessions in OCD patients.There were no differences in platelet MAO activity between OCD patients and healthy controls. We found a significant correlation between platelet MAO activity and Y-BOCS scores in the group of patients with Y-BOCS scores >15.OCD patients with aggressive obsessions had significantly lower levels of platelet MAO activity than patients without aggressive obsessions.Our results suggest that platelet MAO activity may be a marker of OCD severity, and that low platelet MAO activity may be associated with aggressive obsessions in OCD patients.
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Reem aljanabi, Mahmood salih, and Dawood aljanabi. "Comparison between Monoamine Oxidase A and B: role and effect in human diseases: A review." International Journal of Research in Pharmaceutical Sciences 11, SPL4 (December 21, 2020): 2870–77. http://dx.doi.org/10.26452/ijrps.v11ispl4.4573.
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MAOs are isoenzymes that occur in two isoforms Monoamine oxidases A and B. They are flavoproteins found in mitochondria and their role is to catalyze the oxidative deamination of monoamine neurotransmitters to their corresponding aldehydes. Both MAOs play a major role in the human body as they contribute to many illnesses. MAO plays an essential role in both peripheral; and central nervous system through affecting the levels of MAO neurotransmitters. MAO-A is generally concentrated in dopaminergic and norepinephrinergic neurons. Contrary to MAO-B, which is predominantly concentrated in serotoninergic neurons. By-product of MAOs which are aldehyde, ammonia, and H2O2 (which is considered reactive oxygen species) that is toxic at high concentration or it may lead to the generation of free Radicals. Free radicals considered as a starting signal in the generation of cancers. Also, MAO inhibition showed to decrease pressure overload and heart failure. This action is mainly related to the prevention of oxidative stress mainly (H2O2) apoptosis in cardiac muscle and improved bioavailability of Norepinephrine. MAO-A plays a totally different role from MAO—B in renal carcinoma. Ranging from Alzheimer disease, depression to cardiac myopathy, diabetes, kidney diseases, and cancers, MAO-A participates differently from MAO-B in these diseases. Therefore it is necessary to study their separate effect in human diseases and the consequences of their inhibition. In this review, we compare between MAO-A and MAO-B effect from many aspects that includes heart failure, renal carcinoma, breast cancer, esophageal cancer, prostate cancer, bladder cancer, glioma and diabetes. And finally, the role of MAO inhibitors and their effects also have been discussed.
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Oh, Jong Min, T. M. Rangarajan, Reeta Chaudhary, Rishi Pal Singh, Manjula Singh, Raj Pal Singh, Anna Rita Tondo, et al. "Novel Class of Chalcone Oxime Ethers as Potent Monoamine Oxidase-B and Acetylcholinesterase Inhibitors." Molecules 25, no. 10 (May 18, 2020): 2356. http://dx.doi.org/10.3390/molecules25102356.
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Previously synthesized novel chalcone oxime ethers (COEs) were evaluated for inhibitory activities against monoamine oxidases (MAOs) and acetylcholinesterase (AChE). Twenty-two of the 24 COEs synthesized, except COE-17 and COE-24, had potent and/or significant selective inhibitory effects on MAO-B. COE-6 potently inhibited MAO-B with an IC50 value of 0.018 µM, which was 105, 2.3, and 1.1 times more potent than clorgyline, lazabemide, and pargyline (reference drugs), respectively. COE-7, and COE-22 were also active against MAO-B, both had an IC50 value of 0.028 µM, which was 67 and 1.5 times lower than those of clorgyline and lazabemide, respectively. Most of the COEs exhibited weak inhibitory effects on MAO-A and AChE. COE-13 most potently inhibited MAO-A (IC50 = 0.88 µM) and also significantly inhibited MAO-B (IC50 = 0.13 µM), and it could be considered as a potential nonselective MAO inhibitor. COE-19 and COE-22 inhibited AChE with IC50 values of 5.35 and 4.39 µM, respectively. The selectivity index (SI) of COE-22 for MAO-B was higher than that of COE-6 (SI = 778.6 vs. 222.2), but the IC50 value (0.028 µM) was slightly lower than that of COE-6 (0.018 µM). In reversibility experiments, inhibitions of MAO-B by COE-6 and COE-22 were recovered to the levels of reference reversible inhibitors and both competitively inhibited MAO-B, with Ki values of 0.0075 and 0.010 µM, respectively. Our results show that COE-6 and COE-22 are potent, selective MAO-B inhibitors, and COE-22 is a candidate of dual-targeting molecule for MAO-B and AChE.
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Komarova, E. G., E. A. Kazantseva, V. S. Ripenko, A. Zharin, and Y. P. Sharkeev. "Effect of ultraviolet irradiation or diffuse discharge plasma on structure and surface electrical charge of micro-arc calcium phosphate coatings." Journal of Physics: Conference Series 2064, no. 1 (November 1, 2021): 012077. http://dx.doi.org/10.1088/1742-6596/2064/1/012077.
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Abstract The studies of the effect of ultraviolet (UV) irradiation and plasma of a runaway electron preionized diffuse discharge (REP DD) post-treatments on the surface structure and electrical charge of the micro-arc oxidation (MAO) coatings were performed. The UV irradiation and plasma treatment did not effect on the morphology, roughness and thickness of the MAO coatings. However, these post-treatments led to formation of the small fraction of the crystalline CaHPO4phase in the X-ray amorphous structure of the coatings. Moreover, the UV and REP DD plasma treatments increased the electrostatic potential (EP) negative values from –85 mV to –126 mV of the coatings in the following order: MAO < MAO/UV (for 5 min) < MAO/Plasma (with 10,000 pulses) < MAO/UV (for 20 min) < MAO/Plasma (with 80,000 pulses).
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Yun, Liyuan, Conglin Han, Xiaoqing He, Qian Li, Viktor Fersht, and Min Zhang. "Structure Characterization and Immunomodulatory Activity of Misgurnus anguillicaudatus Carbohydrates." Molecules 28, no. 15 (July 31, 2023): 5771. http://dx.doi.org/10.3390/molecules28155771.
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Misgurnus anguillicaudatus, also known as oriental weather loach, is widely consumed and favored in East Asia due to its superior nutritional values and excellent flavor. In this study, a crude Misgurnus anguillicaudatus carbohydrates (MAC) was isolated from Misgurnus anguillicaudatus. Subsequently, two parts, which were named MAO and MAP, respectively, were separated from MAC, and their primary structures and immunomodulatory activity were investigated. The results showed that MAO had a molecular weight of 2854 Da, and principally consisted of arabinose (77.11%) and rhamnose (21.97%), together with minor levels of fucose (0.92%); MAP, with a molecular weight of 3873 Da, was mainly composed of fucose (87.55%) and a small amount of rhamnose (8.86%) and galactose (3.59%). The in vitro assay showed that MAC could significantly enhance the proliferation of macrophages without cytotoxicity and increase the production of immune substances (TNF-α, IL-6). Together with Western blot results, we speculated that MAC could stimulate RAW264.7 murine macrophage cells to secrete TNF-α and IL-6 through up-regulating TLR4-MAPK-p38 signaling pathways. The results indicated that MAC could be a potential immune agent and might provide meaningful information for further chain conformation and immune mechanism research.
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Geng, Xue, Qiangsheng Dong, and Xiaobo Zhang. "Improved Corrosion Properties of Mg-Gd-Zn-Zr Alloy by Micro-Arc Oxidation." Metals 14, no. 2 (February 15, 2024): 236. http://dx.doi.org/10.3390/met14020236.
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In order to improve the corrosion resistance of Mg-3Gd-1Zn-0.4Zr (GZ31K) alloys for biomedical application, the alloy was micro-arc oxidation (MAO)-treated using silicate electrolyte system under various voltages (400 V, 425 V, 450 V, 475 V). The effects of voltage on the microstructure and corrosion properties of MAO coating were investigated via X-ray diffraction (XRD) and a scanning electron microscope (SEM) combined with an energy-dispersive spectrometer (EDS), X-ray photoelectron spectroscope (XPS), and electrochemical experiments. The results showed that, with the increase in voltage, the MAO coatings became thicker and the micropores on the MAO coating increased in diameter. The main phase compositions of the MAO coatings were MgO and Mg2SiO4. Potentiodynamic polarization curve results showed that MAO coatings could enhance corrosion resistances, where the corrosion current density decreased by six orders of magnitude and the corrosion potential of the specimens increased by 300 mV for the voltage of 450 V in the MAO treatment; nevertheless, the corrosion resistance rapidly deteriorated due to the creation of large micropores in the MAO coating, which provide a pathway for corrosive media when the voltage is 475 V. The electrochemical impedance spectroscopy results showed that MAO treatments could increase low-frequency modulus resistance and increase the corrosion resistance of Mg alloys. In addition, MAO-treated GZ31K alloys still exhibited uniform corrosion, which is desirable for biomedical applications.
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Resta, Jessica, Yohan Santin, Mathieu Roumiguié, Elodie Riant, Alexandre Lucas, Bettina Couderc, Claudia Binda, Philippe Lluel, Angelo Parini, and Jeanne Mialet-Perez. "Monoamine Oxidase Inhibitors Prevent Glucose-Dependent Energy Production, Proliferation and Migration of Bladder Carcinoma Cells." International Journal of Molecular Sciences 23, no. 19 (October 4, 2022): 11747. http://dx.doi.org/10.3390/ijms231911747.
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Bladder cancer is the 10th most common cancer in the world and has a high risk of recurrence and metastasis. In order to sustain high energetic needs, cancer cells undergo complex metabolic adaptations, such as a switch toward aerobic glycolysis, that can be exploited therapeutically. Reactive oxygen species (ROS) act as key regulators of cancer metabolic reprogramming and tumorigenesis, but the sources of ROS remain unidentified. Monoamine oxidases (MAOs) are mitochondrial enzymes that generate H2O2 during the breakdown of catecholamines and serotonin. These enzymes are particularly important in neurological disorders, but recently, a new link between MAOs and cancer has been uncovered, involving their production of ROS. At present, the putative role of MAOs in bladder cancer has never been evaluated. We observed that human urothelial tumor explants and the bladder cancer cell line AY27 expressed both MAO-A and MAO-B isoforms. Selective inhibition of MAO-A or MAO-B limited mitochondrial ROS accumulation, cell cycle progression and proliferation of bladder cancer cells, while only MAO-A inhibition prevented cell motility. To test whether ROS contributed to MAO-induced tumorigenesis, we used a mutated form of MAO-A which was unable to produce H2O2. Adenoviral transduction of the WT MAO-A stimulated the proliferation and migration of AY27 cells while the Lys305Met MAO-A mutant was inactive. This was consistent with the fact that the antioxidant Trolox strongly impaired proliferation and cell cycle progression. Most interestingly, AY27 cells were highly dependent on glucose metabolism to sustain their growth, and MAO inhibitors potently reduced glycolysis and oxidative phosphorylation, due to pyruvate depletion. Accordingly, MAO inhibitors decreased the expression of proteins involved in glucose transport (GLUT1) and transformation (HK2). In conclusion, urothelial cancer cells are characterized by a metabolic shift toward glucose-dependent metabolism, which is important for cell growth and is under the regulation of MAO-dependent oxidative stress.
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Cabanillas, A. M., A. M. Masini-Repiso, and A. H. Coleoni. "Rat thyroid monoamine oxidase (MAO) is regulated by thyrotrophin: evidence that the main form of the enzyme (MAO-A) is not directly involved in iodide organification." Journal of Endocrinology 131, no. 1 (October 1991): 25–31. http://dx.doi.org/10.1677/joe.0.1310025.
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ABSTRACT The characteristics and regulation of monoamine oxidase (MAO) were studied in rat thyroid tissue. A measured Michaelis constant (Km) value of 102 μmol/l was similar to the Km values found in other tissues. Maximal velocity (Vmax) was 1·028 nmol/mg protein per min. It is known that MAO is present as two isoenzymes, A and B, which are sensitive to clorgyline and deprenyl respectively. The in-vitro effect of graded concentrations of these selective MAO inhibitors was used to estimate the relative proportion of A and B isoenzymes. Clorgyline strongly decreased thyroid MAO activity at concentrations as low as 1 pmol/l while the effect of deprenyl was observed only at concentrations higher than 10 μmol/l. These results indicated that MAO-A is the main form of the enzyme in the rat thyroid. In-vivo administration of l-thyroxine (5·6–224 nmol/kg) significantly reduced thyroid MAO activity at doses equal to or greater than those which have been reported to inhibit iodine output from the thyroid. Increased TSH levels, induced either by exogenous TSH or methimazole administration, resulted in a significant increase in thyroid MAO activity. Theophylline, a phosphodiesterase inhibitor and dibutyryl cyclic AMP were also able to stimulate MAO activity when administered in vivo. Iodide organification (protein-bound 131I) in vivo as well as the relative proportion of the different thyroid iodocompounds were not affected in animals with reduced or increased thyroid MAO activity induced by clorgyline or theophylline respectively. It was concluded that rat thyroid MAO activity is under the influence of TSH. The adenylcyclase–cyclic AMP system participates in the regulation of enzyme activity as one of the intracellular mediators. An important effect of MAO on thyroid hormone biosynthesis is unlikely since changes in MAO activity did not affect the iodine organification process. Journal of Endocrinology (1991) 131, 25–31
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Zhang, Zhiping, Kevin Chen, Jean C. Shih, and Christina T. Teng. "Estrogen-Related Receptors-Stimulated Monoamine Oxidase B Promoter Activity Is Down-Regulated by Estrogen Receptors." Molecular Endocrinology 20, no. 7 (July 1, 2006): 1547–61. http://dx.doi.org/10.1210/me.2005-0252.
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Abstract Although there are studies published about the neuroprotective effect of estrogen, little is known about the mechanisms and cellular targets of the hormone. Recent reports demonstrate that estrogen down-regulates the expression of monoamine oxidase A and B (MAO-A and MAO-B) in the hypothalamus of the Macaques monkey, both of which are key isoenzymes in the neurotransmitter degradation pathway. Additionally, estrogen-related receptor α (ERRα) up-regulates MAO-B gene expression in breast cancer cells. ERRα recognizes a variety of estrogen response elements and shares many target genes and coactivators with estrogen receptor α (ERα). In this study, we investigate the interplay of ERs and ERRs in the regulation of MAO-B promoter activity. We demonstrate that ERRα and ERRγ up-regulate MAO-B gene activity, whereas ERα and ERβ decrease stimulation in both a ligand-dependent and -independent manner. Ectopically expressed ERRα and ERRγ stimulate the expression of MAO-B mRNA and protein as well as increase the MAO-B enzymatic activity in ER-negative HeLa cells. The ability of ERRs to stimulate MAO-B promoter activity was reduced in ER-positive MCF-7 and T47D cells. Several AGGTCA motifs of the MAO-B promoter are responsible for up-regulation by ERRs. Interestingly, ERα or ERβ alone have no effect on MAO-B promoter activity but can down-regulate the activation function of ERRs, whereas glucocorticoid receptor does not. By using chromatin immunoprecipitation assay, we demonstrate that ERs compete with ERRs for binding to the MAO-B promoter at selective AGGTCA motifs, thereby changing the chromatin status and cofactor recruitment to a repressed state. These studies provide new insight into the relationship between ERα, ERβ, ERRα, and ERRγ in modulation of MAO-B gene activity.
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Riordan, Matt M., and Sándor J. Kovács. "Absence of diastolic mitral annular oscillations is a marker for relaxation-related diastolic dysfunction." American Journal of Physiology-Heart and Circulatory Physiology 292, no. 6 (June 2007): H2952—H2958. http://dx.doi.org/10.1152/ajpheart.01356.2006.
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Although Doppler tissue imaging frequently indicates the presence of mitral annular oscillations (MAO) following the E′ wave (E″ wave, etc.), only recently was it shown that annular “ringing” follows the rules of damped harmonic oscillatory motion. Oscillatory model-based analysis of E′ and E″ waves provides longitudinal left ventricular (LV) stiffness ( k′), relaxation/viscoelasticity ( c′), and stored elastic strain ( xo′) parameters. We tested the hypothesis that presence (MAO+) vs. absence (MAO−) of diastolic MAO is an index of superior LV relaxation by analyzing simultaneous echocardiographic-hemodynamic data from 35 MAO+ and 20 MAO− normal ejection fraction (EF) subjects undergoing cardiac catheterization. Echocardiographic annular motion and transmitral flow data were analyzed with a previously validated kinematic model of filling. Invasive and noninvasive diastolic function (DF) indexes differentiated between MAO+ and MAO− groups. Specifically, the MAO+ group had a shorter time constant of isovolumic relaxation [τ; 51 (SD 13) vs. 67 (SD 27) ms; P < 0.01] and isovolumic relaxation time [63 (SD 16) vs. 82 (SD 17) ms; P < 0.001] and greater ratio of peak E-wave to peak A-wave velocity [1.19 (SD 0.31) vs. 0.97 (SD 0.31); P < 0.05]. The MAO+ group had greater peak lateral mitral annulus velocity [E′; 17.5 (SD 3.1) vs. 13.5 (SD 3.8) cm/s; P < 0.001] and LVEF [71.2 (SD 7.5)% vs. 65.4 (SD 9.1)%; P < 0.05] and lower heart rate [65 (SD 9) vs. 74 (SD 9) beats/min, P < 0.001]. Additional conventional and kinematic modeling-derived indexes were highly concordant with these findings. We conclude that absence of early diastolic MAO is an easily discernible marker for relaxation-related diastolic dysfunction. Quantitation of MAO via stiffness and relaxation/viscoelasticity parameters facilitates quantitative assessment of regional (i.e., longitudinal) DF and may improve diagnosis of diastolic dysfunction.
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Zhang, Rongfa, Sheng Zhong, Lilan Zeng, Hongyu Li, Rongfang Zhao, Shufang Zhang, Xinting Duan, Jingsong Huang, and Ying Zhao. "Novel Mg-Incorporated Micro-Arc Oxidation Coatings for Orthopedic Implants Application." Materials 14, no. 19 (September 30, 2021): 5710. http://dx.doi.org/10.3390/ma14195710.
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In this study, Ti-6Al-4V alloy samples were processed by micro-arc oxidation (MAO) in phytic acid (H12Phy) electrolytes with the addition of different concentrations of EDTA-MgNa2 (Na2MgY) and potassium hydroxide (KOH). The surface characterization and cytocompatibility of MAO-treated samples were evaluated systematically. H12Phy is a necessary agent for MAO coating formation, and the addition of Na2MgY and KOH into the electrolytes increases the surface roughness, micropore size and Mg contents in the coatings. The MAO coatings are primarily composed of anatase, rutile, MgO and Mg3(PO4)2. Magnesium (Mg) ions in the electrolytes enter into MAO coatings by diffusion and electromigration. The MAO coatings containing 2.97 at% Mg show excellent cell viability, adhesion, proliferation, alkaline phosphatase activity, extracellular matrix (ECM) mineralization and collagen secretion, but the cytocompatibility of the MAO coatings containing 6.82 at% Mg was the worst due to the excessively high Mg content. Our results revealed that MAO coatings with proper Mg contents improve the cytocompatibility of the Ti-6Al-4V alloys and have large potential in orthopedic applications.
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Soufi, W., M. Merad, F. BOUKLI Hacene, and S. Ghalem. "Study of Monoamine Oxidase-B and Indole Derivatives Using Two Molecular Docking Programs: Molegro and MOE." International Journal of Scientific Research and Management 8, no. 09 (September 30, 2020): 25–31. http://dx.doi.org/10.18535/ijsrm/v8i09.c01.
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Inhibition of the enzyme Monoamine oxidase (MAO) is an important approach in the treatment of Parkinson’s disease. A series of indole derivatives were synthesised and evaluated as inhibitors of MAO-B may give insight to develop new ways of antiparkinson drug, In general, the derivatives were found to be selective MAO-B inhibitors with IC50 values . MAO-B inhibitors, are considered useful in the therapy of Parkinson’s disease since oxidation by MAO-B represents a major catabolic pathway of dopamine in the central nervous system .
Our goal of research is to study the inhibition of MAO-B by molecular modeling methods. Different molecular modeling tools are used to perform this work (molecular mechanics, molecular dynamics and molecular docking by two programms MDV ( molegro virtual docker) and MOE (modelling Opering Environment. The results obtained from this work, into which the inhibition of MAO-B by molecular modeling methods was elucidated, allow us to conclude that indole derivatives are promising reversible MAO-B inhibitors with a possible role in the treatment of neurodegenerative diseases such as Parkinson’s disease (PD).