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Introduction to dermatological treatment
Published in Richard Ashton, Barbara Leppard, Differential Diagnosis in Dermatology, 2021
Richard Ashton, Barbara Leppard
A photosensitising chemical, 5-amino-levulinic acid (ALA), is converted to protoporphyrin-9 when irradiated with red light (630 nm). The porphyrin accumulates in the abnormal cells and in the presence of oxygen releases singlet oxygen which causes cell death. Topical ALA is available as the methyl ester (methyl aminolevulinate, Metvix cream). The methyl ester has the advantage of being taken up preferentially into neoplastic cells (due to their defective stratum corneum).
Critical Review of Evidence for Neonatal Cocaine Intoxication and Withdrawal
Published in Richard J. Konkol, George D. Olsen, Prenatal Cocaine Exposure, 2020
Delia A. Dempsey, Donna M. Ferriero, Sarah N. Jacobson
Ecgonine methyl ester is the second most abundant metabolite of cocaine found in the urine.77 Plasma pseudocholinesterases and liver esterase catalyze the conversion of cocaine to ecgonine methyl ester.40,83 Neonatal pseudocholinesterase activities are not significantly different than in adults, but they cluster in the low normal adult range and there is great individual variation.3,84 Based on urinary data, the half-life of ecgonine methyl ester is 4.2 hours.7 For a review of the pharmacologic activity of ecgonine methyl ester see Chapters 5 and 6.
Gas Chromatography
Published in Joseph Chamberlain, The Analysis of Drugs in Biological Fluids, 2018
In cases where poor volatility is due to intermolecular hydrogen bonding, the volatility can be increased by masking such bonding groups by forming appropriate derivatives, such as acylation of amines or hydroxy groups and esterification of organic acids. For esterification the classical methylation procedure using diazomethane has largely been replaced by the less hazardous boron trifluoridemethanol reagent. For esters other than methyl esters, other alcohols can be used which is particularly useful if the methyl ester may be present naturally in the sample. Barbiturates can be N-methylated using diazomethane,472 dimethylsulfate,473 or trimethyl phenylammonium hydroxide.474
Fatty acids, esters, and biogenic oil disinfectants: novel agents against bacteria
Published in Baylor University Medical Center Proceedings, 2023
Aruna Lamba, Jonathan Kopel, David Westenberg, Shubhender Kapila
A recent study by Westenberg et al showed that aerosols/vapors obtained from mineral oil or vegetable oil ester under proper conditions can serve as an excellent antibacterial disinfectant.40 It was determined that vegetable oil esters had greater antibacterial activity than FOG oil. The presence of unsaturated fatty acids, which are easily converted to aldehydes and ketones, may be the cause of this. The most effective antibacterial compounds were methyl soyate and olive oil fumes from methyl ester aerosol.40 Westenberg et al argued that the primary mode of action is the destruction of the bacterial cell wall and membrane, although other mechanisms may also contribute to the oil’s antibacterial activity. The study demonstrated the potential use of volatile biogenic oils as novel antimicrobials and disinfectants for future investigation and clinical application. Subsequently, the volatile and semivolatile organics were characterized with gas chromatography–mass spectroscopy, and several candidate compounds responsible for the antibacterial activity were identified.41
Protective Effect of Tunisian Flaxseed Oil against Bleomycin-Induced Pulmonary Fibrosis in Rats
Published in Nutrition and Cancer, 2020
Anouar Abidi, Nadia Kourda, Moncef Feki, Saloua Ben Khamsa
Chromatographic separation and identification of components of FO, lung tissue and reds blood cells were performed on a gas chromatography apparatus (6890 N, Agilent Technologies, Santa Clara, CA) equipped with a flame ionization detector and capillary column HP-Innowax (30 m × 0.32 mm × 0.25 m). The amount of each sample injected was 1 mL. Nitrogen, at a constant flow 1.0 mL/min, was used as the carrier gas, and a split/splitless injector was used with a split ratio of 50:1. The injector temperature was 230 °C, and the detector temperature was 280 °C. The column temperature was programed according to the following: initial temperature was 150 °C for 1 min and then increased 15 °C/min to 210 °C and maintained for 5 min before being readjusted again 5 °C/min to 250 °C and then maintained until the end of the analysis, which takes 25 min. Fatty acid methyl esters were identified by comparison with the standard fatty acid methyl esters (Sigma, USA) and were quantified as percentages of the total methyl ester peak areas.
Co-Culture Probiotic Fermentation of Protein-Enriched Cereal Medium (Boza)
Published in Journal of the American College of Nutrition, 2020
Sultan Arslan-Tontul, Mustafa Erbas
The main VOCs, detected during cereal fermentation, were reported to be formed as a result of carbohydrate and amino acid metabolisms (33). During fermentation, the most abundant compounds were 9,12-octadecadienoic acid, 9-octadecenoic acid, hexadecanoic acid, and hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester. These findings are in agreement with Salmeron, Fucinos, Charalampopoulos, and Pandiella (3), who determined that the major VOCs were oleic and linoleic acid after fermentation of cereals by Lactobacillus plantarum. Also, Ogunremi, Agrawal, and Sanni (38) determined 9,12-octadecadienoic acid methyl ester as the major aromatic compounds in a substrate mix fermented with a probiotic strain of Pichia kudriavzevii. In addition, esters were attributed to major aromatic and flavor compounds formed during LAB and yeast fermentation (39). 9,12-octadecadienoic acid and 9-octadecenoic acid can act as precursors for flavor compounds such as methyl ketones, alcohols, and lactones, but these acids could be attributed to yeast activity more than LAB due to their low lypolitic activities (33).