The intragastric formation of nitrosodimethylamine (NDA) by bacteria existing in the gastrointestinal tract of monkey was examined by determining the in vitro formation of nitrosodimethylamine from nitrite and dimethylamine in the brain-heart-infusion (BHI) medium, adjusted to pH 6 with gastric juice containing 5000 ppm sodium nitrate and 1000 ppm dimethylamine. Nitrosodimethylamine formation depended on the activity of the nitrate-reducing bacteria in the stomach contents of the monkey, and the concn of nitrite was clearly related to the amount of nitrosodimethylamine. NDA was formed in the brain-heart-infusion medium alone at pH 5 and 6. The addition of gastric juice to the medium increased the formation of nitrosodimethylamine.
The extent of nitrosamine formation and the metabolism of the resultant nitrosamines in vivo were investigated by using (15)N-stable isotope labeling and by the determination of the isotope ratio in the expired N. (15)N-labeled dimethylamine (1.1 mmol/kg) and various doses of nonlabeled nitrile (0.55-2.2 mmol/kg) or labeled nitrile without dimethylamine administered to male rats, which were placed in an enclosed respiratory system. The system was flushed with a mixture containing 80% He and 20% O, and N content of the recirculating atmosphere was determined. When labeled dimethylamine and nonlabeled nitrile were administered, nitrile reacted with secondary amines, followed by enzymic alpha-hydroxylation and decomposition of the ensuing alkyldiazohydroxide to molecular N and an alkyl cation as ultimate carcinogen. When (15)N nitrile was administered, N was released (nitrile reacted with primary amines to release molecular N and formation of the corresponding alcohol or olefin).
Dimethylamine is the immediate precursor of dimethylnitrosamine, a known potent carcinogen in a wide variety of animal species. Although small amounts of dimethylamine are ingested directly, the major dietary source is believed to be via choline and related materials. Owing to quantitative recoveries following oral administration, urinary dimethylamine levels provide good overall measures of body exposure. The oral administration of equimolar amounts (1 mmol/kg body weight) of potential amine precursors to male Wistar rats produced only small increases in urinary dimethylamine after choline (+ 11%; 0.60 +/- 0.36% dose), dimethylaminopropanol (+ 32%; 1.49 +/- 0.30% dose), dimethylaminoethyl chloride (+ 110% 5.38 +/- 1.72% dose) and trimethylamine (+ 51%; 1.6 +/- 0.80% dose) input, whereas significantly larger increases were found following trimethylamine N-oxide ingestion (+ 355%; 12.93 +/- 1.13% dose; t-test, P < 0.001). These data suggest that trimethylamine N-oxide is a major dietary source of dimethylamine, by direct conversion and not by sequential reduction (to trimethylamine) and demethylation, and that in this respect it is of greater importance, on a molar basis, than choline.
Uremic toxins tend to accumulate in the blood either through dietary excess or through poor filtration by the kidneys. Most uremic toxins are metabolic waste products and are normally excreted in the urine or feces.
IDENTIFICATION AND USE: Dimethylamine (DMA) is a colorless gas. It is used as acid-gas absorbent, solvent antioxidants, manufacture of dimethylformamide and dimethylacetamide, dyes, flotation agent, gasoline stabilizers, pharmaceuticals, textile chemicals, rubber accelerators, electroplating, dehairing agent, missile fuels, pesticide propellant, rocket propellants, surfactants, reagent for magnesium. HUMAN STUDIES: Workers in a foundry complaining of breathlessness and choking were found to be exposed to 1-46 mg/cu m DMA in the air. Vision has become misty and halos have appeared several hours after workmen have been exposed to the vapors of DMA at concentration too low to cause discomfort or disability during several hours of exposure. The edema of the corneal epithelium, which is principally responsible for the disturbance of vision, clears spontaneously by the next day, but after exceptionally intense exposures the edema and blurring have taken several days to clear and have been accompanied by photophobia and discomfort from roughness of the corneal surface. ANIMAL STUDIES: A 6% solution of DMA, when applied to the skin of rabbits, caused reddening, then thickening and ulceration after a single treatment. A 3% solution produced similar effects after five treatments. A 5% DMA solution dropped once on rabbit eye caused hemorrhages in conjunctiva, corneal edema, and superficial opacities. A drop of undiluted DMA placed on rabbit's cornea, with the lids then closed and no irrigation performed, caused the cornea to become whitish blue and translucent within few sec, then white as sclera in a min. DMA was a skin sensitizer in the guinea pig closed epicutaneous test. Histopathologic evaluation of the respiratory tract of rats exposed by inhalation at single concentrations ranging from 600 to 6000 ppm for 6 hr revealed concentration-related changes ranging from ulceration and necrosis to rhinitis, tracheitis, and emphysema. Mice exposed at 813 to 1626 ppm DMA had ocular and respiratory irritation and that cyanosis, convulsions, and death occurred above 5420 ppm. Pathologic evaluation revealed massive hemorrhages near the periphery of the lungs and peripheral emphysema in those mice that died during exposure. Small hemorrhages were found in the lungs of mice sacrificed 20 days postexposure. In a repeated exposure study, mice were exposed by inhalation 6 hours/day for 5 days at 511 ppm of DMA. Body weight decreased by 10% to 25% in all animals, and 3 of 24 mice died during exposure. Nasal lesions were observed in these animals. DMA was not carcinogenic by the inhalation in mice and rats. DMA was weakly mutagenic in Salmonella typhimurium strain TA 1530 in the presence of metabolic activation. No mutagenic activity occurred without activation, and no activity was found in a host-mediated assay in mice.
Uremic toxins such as dimethylamine are actively transported into the kidneys via organic ion transporters (especially OAT3). Increased levels of uremic toxins can stimulate the production of reactive oxygen species. This seems to be mediated by the direct binding or inhibition by uremic toxins of the enzyme NADPH oxidase (especially NOX4 which is abundant in the kidneys and heart) (A7868). Reactive oxygen species can induce several different DNA methyltransferases (DNMTs) which are involved in the silencing of a protein known as KLOTHO. KLOTHO has been identified as having important roles in anti-aging, mineral metabolism, and vitamin D metabolism. A number of studies have indicated that KLOTHO mRNA and protein levels are reduced during acute or chronic kidney diseases in response to high local levels of reactive oxygen species (A7869)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌性证据
A4;不能归类为人类致癌物。
A4; Not classifiable as a human carcinogen.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌物分类
对人类无致癌性(未列入国际癌症研究机构IARC清单)。
No indication of carcinogenicity to humans (not listed by IARC).
来源:Toxin and Toxin Target Database (T3DB)
毒理性
健康影响
长期暴露于尿毒症毒素可能会导致多种疾病,包括肾脏损伤、慢性肾病和心血管疾病。
Chronic exposure to uremic toxins can lead to a number of conditions including renal damage, chronic kidney disease and cardiovascular disease.
The disposition and pharmacokinetics of [(14)C]dimethylamine [(14)C] DMA) following 6-hr inhalation of either 10 or 175 ppm were determined in male Fischer 344 rats. Seventy-two hours after termination of exposure, the disposition of recovered radioactivity was similar for each airborne concentration, with more than 90% in the urine and feces, 7 to 8% in selected tissues and the carcass, and 1.5% exhaled as (14)CO2. Over 98% of the radioactivity in the urine was unmetabolized DMA. Analysis of tissue radioactivity immediately after exposure to [(14)C]DMA showed that the respiratory nasal mucosa contained the highest concentration of (14)C, followed by the olfactory nasal mucosa; concentrations of (14)C in liver, lung, kidney, brain, and testes were approximately 2 orders of magnitude less than in the nasal mucosal tissues. Radioactivity in plasma of rats exposed by inhalation to 175 ppm of [(14)C]DMA decayed in a biphasic manner. The terminal half-life for plasma radioactivity was similar to the half-lives of some plasma proteins, suggesting incorporation of (14)C into proteins subsequent to metabolism of [(14)C]DMA. The results indicate that, while most of the inhaled DMA is excreted unchanged, a small amount of oxidative metabolism of DMA occurs.
1. The fate of [(14)C]-dimethylamine was investigated following oral administration to four male volunteers. 2. The major route of excretion was urine, with 94% of the administered radioactivity being voided over 3 days (87% during the first 24 hr). Small amounts (1-3%) of radioactivity were found in the faeces and expired air. 3. Metabolism was limited with only 5% being demethylated to methylamine. The remainder of the dose was excreted unchanged. 4. Pharmacokinetic studies indicated rapid (t1/2ab = 8 min) and extensive absorption (bioavailability = 82%) from the gastrointestinal tract followed by widespread distribution and a fairly prompt excretion (t1/2el = 6-7 hr) with a plasma clearance of 190 mL/min.
The urinary excretion of dimethylamine has been measured in 203 unrelated healthy volunteers (102 male) who maintained their normal diets. ... The average daily output was 17.43 +/- 11.80 mg (mean +/- SD) (21.21 +/- 14.78 male; 13.74 +/- 5.65 female) with values for the majority of the population lying within the 0.68-35.72 mg range. Four male outliers excreted up to 109.2 mg; these large amounts of dimethylamine were presumed to be of dietary origin. ...
In the gastro-intestinal tract of male Wistar rats fed a commercial diet containing 23.6 ppm dimethylamine (DMA), the concentration of DMA was highest (11.2 +/- 2.1 ppm) in the stomach and declined towards the lower regions. In contrast, the highest DMA concentration (6.6 +/- 2.5 ppm) was observed in the upper small intestine in rats fed a diet containing only 1.0 ppm DMA. DMA was absorbed in the intestines, and the disappearance curves were monoexponential. The t1/2 values for DMA in the ligated stomach, upper and lower small intestine, caecum and large intestine were 198, 8.3, 11.6, 31.5 and 11.0 min, respectively. The DMA concentration in the blood had increased to 3.0 +/- 1.0 ppm (from a pre-injection level of 0.28 +/- 0.06 ppm) 5 min after the injection of 250 micrograms DMA into the ligated upper small intestine. The disappearance curve for DMA in the blood was monoexponential and the t1/2 for the initial 15 min was 12.5 min when 250 micrograms DMA was injected into a femoral vein. The peak concentrations of DMA in the intestine and bile, respectively, were 15.6 +/- 12.6 ppm (at 15 min) and 3.7 +/- 1.9 ppm (at 30 min after the iv injection of DMA). In this 30-min period, urinary DMA increased from 17.3 +/- 9.4 to 139 +/- 23 ppm. These results show that, following ingestion, DMA is absorbed from the intestine into the blood, from which it disappears rapidly, the major part being excreted in the urine while a small proportion is excreted in the bile or secreted into the intestine, where it may be reabsorbed.
Application of the WATR Technique for Water Suppression in 1H NMR Spectroscopy in Determination of The Kinetics of Hydrolysis of Neostigmine Bromide in Aqueous Solution
medium. Dimethylchloramine prepared in a pure state undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N-methylmethanimine, 1,3,5-trimethylhexahydrotriazine, formaldehyde, and methylamine. The kinetics of this reaction was studied by UV, GC, and HPLC as a function of temperature, initial concentrations of sodium hydroxide, and chlorinated derivative. The reaction is of
[EN] IMIDAZOLE DERIVATIVES USEFUL AS INHIBITORS OF FAAH<br/>[FR] DÉRIVÉS IMIDAZOLE UTILES COMME INHIBITEURS DE LA FAAH
申请人:MERCK & CO INC
公开号:WO2009152025A1
公开(公告)日:2009-12-17
The present invention is directed to certain imidazole derivatives which are useful as inhibitors of Fatty Acid Amide Hydrolase (FAAH). The invention is also concerned with pharmaceutical formulations comprising these compounds as active ingredients and the use of the compounds and their formulations in the treatment of certain disorders, including osteoarthritis, rheumatoid arthritis, diabetic neuropathy, postherpetic neuralgia, skeletomuscular pain, and fibromyalgia, as well as acute pain, migraine, sleep disorder, Alzeimer Disease, and Parkinson's Disease.
Asymmetric Synthesis and Absolute Configuration Assignment of a New Type of Bedaquiline Analogue
作者:Chang-Jiang Qiao、Xiao-Kui Wang、Fei Xie、Wu Zhong、Song Li
DOI:10.3390/molecules201219846
日期:——
Bedaquiline is the first FDA-approved new chemical entity to fight multidrug-resistant tuberculosis in the last forty years. Our group replaced the quinoline ring with a naphthalene ring, leading to a new type of triarylbutanol skeleton. An asymmetric synthetic route was established for our bedaquiline analogues, and the goal of assigning their absolute configurations was achieved by comparison of experimental and calculated electronic circular dichroism spectra, and was confirmed by the combined use of circular dichroism and NMR spectroscopy.
Compositions for Treatment of Cystic Fibrosis and Other Chronic Diseases
申请人:Vertex Pharmaceuticals Incorporated
公开号:US20150231142A1
公开(公告)日:2015-08-20
The present invention relates to pharmaceutical compositions comprising an inhibitor of epithelial sodium channel activity in combination with at least one ABC Transporter modulator compound of Formula A, Formula B, Formula C, or Formula D. The invention also relates to pharmaceutical formulations thereof, and to methods of using such compositions in the treatment of CFTR mediated diseases, particularly cystic fibrosis using the pharmaceutical combination compositions.
Nucleic acid related compounds. 47. Synthesis and biological activities of pyrimidine and purine "acyclic" nucleoside analogs
作者:Morris J. Robins、Peter W. Hatfield、Jan Balzarini、Erik De Clercq
DOI:10.1021/jm00377a018
日期:1984.11
Various acyclic, i.e., (2-hydroxyethoxy)methyl and (2-acetoxyethoxy)methyl, analogues of pyrimidine and purinenucleosides have been prepared and evaluated for their antiviral, antimetabolic, and cytotoxic properties. All of the pyrimidine analogues, including (E)-5-(2-bromovinyl)-1-[(2-hydroxyethoxy)methyl]uracil (12) and its O-acetyl derivative (13), were virtually devoid of antiviral, cytotoxic