Search results for "Methylamine"
showing 10 items of 97 documents
Diabetes is Associated with Higher Trimethylamine N-oxide Plasma Levels
2016
Recent studies have revealed strong associations between systemic trimethylamine N-oxide (TMAO) levels, atherosclerosis and cardiovascular risk. In addition, plasma L-carnitine levels in patients with high TMAO concentrations predicted an increased risk for cardiovascular disease and incident major adverse cardiac events. The aim of the present study was to investigate the relation between TMAO and L-carnitine plasma levels and diabetes. Blood plasma samples were collected from 12 and 20 weeks old db/db mice and patients undergoing percutaneous coronary intervention. Diabetic compared to non-diabetic db/L mice presented 10-fold higher TMAO, but lower L-carnitine plasma concentrations at 12 …
Plasma trimethylamine-N-oxide and related metabolites are associated with type 2 diabetes risk in the Prevención con Dieta Mediterránea (PREDIMED) tr…
2018
Background The role of trimethylamine-N-oxide (TMAO) in type 2 diabetes (T2D) is currently partially understood and controversial. Objective The aim of this study was to investigate associations between TMAO and related metabolites with T2D risk in subjects at high risk of cardiovascular disease. Design This is a case-cohort design study within the Prevencion con Dieta Mediterranea (PREDIMED) study, with 251 incident T2D cases and a random sample of 694 participants (641 noncases and 53 overlapping cases) without T2D at baseline (median follow-up: 3.8 y). We used liquid chromatography-tandem mass spectrometry to measure plasma TMAO, l-carnitine, betaine, lyso-phosphatidylcholine (LPC) and l…
Modulation of the gut microbiota impacts nonalcoholic fatty liver disease: A potential role for bile acids
2017
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, yet the pathogenesis of NAFLD is only partially understood. Here, we investigated the role of the gut bacteria in NAFLD by stimulating the gut bacteria via feeding mice the fermentable dietary fiber, guar gum (GG), and suppressing the gut bacteria via chronic oral administration of antibiotics. GG feeding profoundly altered the gut microbiota composition, in parallel with reduced diet-induced obesity and improved glucose tolerance. Strikingly, despite reducing adipose tissue mass and inflammation, GG enhanced hepatic inflammation and fibrosis, concurrent with markedly elevated plasma and hepatic bile acid l…
In vivo antigenotoxic effects of dietary allyl sulfides in the rat
1997
The effects of dietary administration of diallyl sulfide (DAS), diallyl disulfide (DADS) and allyl mercaptan (AM) on the genotoxicity of different chemicals were studied in two experimental systems: (i) measurement of hepatic DNA single-strand breaks induced in rats by aflatoxin B1 (AFB1), N-nitrosodimethylamine (NDMA) or methylnitrosourea (MNU); (ii) mutagenicity of AFB1 or NDMA on Salmonella typhimurium TA100 using hepatic S9 from rats fed allyl sulfides as the activation system. All compounds strongly reduced hepatic DNA breaks induced by AFB1 and NDMA but did not modify the genotoxicity of MNU. In the Ames test, the mutagenicity of NDMA was strongly inhibited by hepatic S9 from rats fed…
Choline Metabolism and Risk of Atrial Fibrillation and Heart Failure in the PREDIMED Study
2020
Abstract Background Few studies have examined the associations of trimethylamine-N-oxide (TMAO) and its precursors (choline, betaine, dimethylglycine, and L-carnitine) with the risk of atrial fibrillation (AF) and heart failure (HF). This study sought to investigate these associations. Methods Prospective associations of these metabolites with incident AF and HF were examined among participants at high cardiovascular risk in the PREDIMED study (PREvención con DIeta MEDiterránea) after follow-up for about 10 years. Two nested case-control studies were conducted, including 509 AF incident cases matched to 618 controls and 326 HF incident cases matched to 426 controls. Plasma levels of TMAO an…
Controllable coverage of chemically modified graphene sheets with gold nanoparticles by thermal treatment of graphite oxide with N,N-dimethylformamide
2013
Abstract We describe a simple chemical method to reduce and functionalize graphite oxide by reaction with dimethylformamide under controlled heating. Our experiments suggest that the reaction conditions assist the decomposition of the solvent to produce dimethylamine molecules that can react with the oxygen-rich functional groups covering the surface of the exfoliated layers of graphene, therefore generating chemically modified graphene (CMG). These N-functionalities have been next used as anchoring points for the grafting of Au nanoparticles. Given that the functionalization extent can be controlled with the temperature and reaction time, our approach can be considered as a straightforward…
Photoinduced functionalization of diterpenes: transformation of the C-20 methyl of atractyligenin into a carbomethoxymethyl or carbamoylmethyl group
2003
Abstract Irradiation of the nor-diterpene atractyligenin 1a and of its methyl ester 1b at λ=254 nm in methanol or in methanol in the presence of nitrogen nucleophiles such as ammonia or methylamine gave, besides the decarboxylation product 2, the ester 3a or the amides 3b, 3c, respectively, providing the transformation of the C-20 angular methyl into a carbomethoxymethyl or carbamoylmethyl group. A photochemical pathway involves formation of C-19/C-20 bond in the excited state, followed by a collapse into a ketene intermediate which will capture the nucleophilic reagent.
Preparation and reactivity of 1,2-bis(imino)ethylpalladium(II) complexes
1982
Abstract The 1,2-bis(imino)ethylpalladium complex, t r a n s − [ P d C I { C ( = N R ) ︹ C H = N R } ( P P h 3 ) 2 ] (R =p-C6H4OMe, DABI) can be prepared by treatment of [Pd(PPh3)4] with two equivalents of CNC6H4OMe-p followed by slow addition of HCl at −70° C. The σ-bonded 1,2-bis(imino) group can be easily monoprotonated and undergoes acid hydrolysis to give the α-aldehydoimidoyl derivative t r a n s − [ P d C I { C ( = N R ) ︹ C H = O } ( P P h 3 ) 2 ] . Condensation of the aldehydic carbonyl group with methylamine yields the product t r a n s − [ P d C I { C ( = N C 6 H 4 O M e − p ) ︹ C H = N M e } ( P P h 3 ) 2 ] , DABII, with different substituents on the N-imino atoms. Substitution …
On the reaction of some 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine: synthesis of fluorinated indazoles
2009
The reaction of 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine has been studied and the synthesis of fluorinated N-methylindazoles has been realized. Rearrangement reactions showed predominantly formation of N(1)-methylindazole regioisomers. Starting compounds were preliminarily functionalized at the polyfluoroaryl moiety through fluorine displacement with nucleophiles (methanol, methylamine, dimethylamine), allowing the obtainment of target indazoles substituted at the C(6) position.
Structure and Function of CutC Choline Lyase from Human Microbiota Bacterium Klebsiella pneumoniae.
2015
CutC choline trimethylamine-lyase is an anaerobic bacterial glycyl radical enzyme (GRE) that cleaves choline to produce trimethylamine (TMA) and acetaldehyde. In humans, TMA is produced exclusively by the intestinal microbiota, and its metabolite, trimethylamine oxide, has been associated with a higher risk of cardiovascular diseases. Therefore, information about the three-dimensional structures of TMA-producing enzymes is important for microbiota-targeted drug discovery. We have cloned, expressed, and purified the CutC GRE and the activating enzyme CutD from Klebsiella pneumoniae, a representative of the human microbiota. We have determined the first crystal structures of both the choline-…