scholarly journals Effects of Different Phases of Cigarette Smoke on Lipid Peroxidation and Membrane Structure in Liposomes

2014 ◽  
Vol 67 (6) ◽  
pp. 858 ◽  
Author(s):  
Nadezhda P. Palmina ◽  
Elena L. Maltseva ◽  
Tatyana E. Chasovskaya ◽  
Valery V. Kasparov ◽  
Nataliya G. Bogdanova ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Double Bond ◽  
Gas Phase ◽  
Lipid Bilayer ◽  
Cigarette Smoke ◽  
Membrane Structure ◽  
Malonic Dialdehyde ◽  
Oxidation Products ◽  
Liposomal Membranes ◽  
First Time

This paper discloses for the first time the effects of the gas phase (GP) and the tar of cigarette smoke on lipid peroxidation (LPO) and on the structure of different lipid regions in liposomes. The LPO development was analysed in terms of the total unsaturation of lipids (double-bond, DB, content) and the formation of dienic conjugates (DC), ketodienes (KD), and malonic dialdehyde (MDA). As expected, the exposure of liposomes to either the GP or the tar led to a significant decrease in the DB content. However, the formation of oxidation products revealed different dynamics: MDA generation was inhibited, while the formation of DC and KD increased during the first few hours of the LPO development followed by its inhibition. The smoke constituents exhibited opposite effects on the structure of the lipid bilayer of liposomes: the GP markedly enhanced the microviscosity of liposomal membranes, whereas the tar caused a drastic lowering of microviscosity.

scholarly journals Atmospheric fate of two relevant unsaturated ketoethers: kinetics, products and mechanisms for the reaction of hydroxyl radicals with (<i>E</i>)-4-methoxy-3-buten-2-one and 1-(<i>E</i>)-1-methoxy-2-methyl-1-penten-3-one

2020 ◽  
Author(s):  
Rodrigo Gastón Gibilisco ◽  
Ian Barnes ◽  
Iustinian Gabriel Bejan ◽  
Peter Wiesen
Keyword(s):  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Relative Rate ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Ozone Formation Potential ◽  
Nitrogen Containing Compounds ◽  
First Time

Abstract. The kinetics of the gas-phase reactions of hydroxyl radicals with two unsaturated methoxy-ketones at (298 ± 3) K and 1 atm of synthetic air have been studied for the first time using the relative rate technique in an environmental reaction chamber by in situ FTIR spectrometry. The rate coefficients obtained using propene and isobutene as reference compounds were (in units of 10–10 cm3 molecule−1 s−1) as follows: k1(OH + (E)-4-methoxy-3-buten-2-one) = (1.42 ± 0.12), and k2(OH + 1-(E)-1-methoxy-2-methyl-1-penten-3-one) = (3.34 ± 0.43). In addition, quantification of the main oxidation products has been performed and degradation mechanisms for these reactions were developed. The formation products and kinetic data confirm that the reactions proceed mainly via an addition of the OH radical to the double bond. Gas phase products, identified and quantified from these reactions, are carbonyls like methyl formate, methyl glyoxal and 2,3-pentanedione and long-lived nitrogen containing compounds such as PAN and PPN. Atmospheric lifetimes and the ozone formation potential have been estimated and possible atmospheric implications assessed.

scholarly journals Gas phase oxidants of cigarette smoke induce lipid peroxidation and changes in lipoprotein properties in human blood plasma. Protective effects of ascorbic acid

1991 ◽  
Vol 277 (1) ◽  
pp. 133-138 ◽  
Author(s):  
B Frei ◽  
T M Forte ◽  
B N Ames ◽  
C E Cross
Keyword(s):  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Blood Plasma ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Human Blood ◽  
Biological Fluids ◽  
Human Blood Plasma ◽  
Lipid Hydroperoxides ◽  
Protein Thiols

Cigarette smoke (CS) is known to contain a large number of oxidants. In order to assess the oxidative effects of CS on biological fluids, we exposed human blood plasma to filtered (gas phase) and unfiltered (whole) CS, and determined the rate of utilization of endogenous antioxidants in relation to the appearance of lipid hydroperoxides. Lipid peroxidation was measured with a specific and sensitive assay that can detect lipid hydroperoxides at plasma levels as low as 10 nM. We found that exposure of plasma to the gas phase of CS, but not to whole CS, induces lipid peroxidation once endogenous ascorbic acid has been oxidized completely. In addition, CS exposure caused oxidation of plasma protein thiols and albumin-bound bilirubin, whereas uric acid and alpha-tocopherol were not consumed at significant rates. In plasma exposed to the gas phase of CS, low-density lipoprotein exhibited slightly increased electrophoretic mobility, but there was no apparent degradation of apolipoprotein B. Our results support the concept of an increased vitamin C utilization in smokers, and suggest that lipid peroxidation induced by oxidants present in the gas phase of CS leads to potentially atherogenic changes in lipoproteins.

scholarly journals Oxidation product characterization from ozonolysis of the diterpene ent-kaurene

2021 ◽  
Author(s):  
Yuanyuan Luo ◽  
Olga Garmash ◽  
Haiyan Li ◽  
Frans Graeffe ◽  
Arnaud P. Praplan ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Atmospheric Chemistry ◽  
Ambient Air ◽  
Proton Transfer Reaction ◽  
Oxidation Products ◽  
Ionization Mass ◽  
Product Characterization ◽  
First Time ◽  
Clustering Patterns

Abstract. Diterpenes (C20H32) are biogenically emitted volatile compounds that only recently have been observed in ambient air. They are expected to be highly reactive, and their oxidation is likely to form condensable vapors. However, until now, no studies have investigated gas-phase diterpene oxidation. In this paper, we explored the ozonolysis of a diterpene, ent-kaurene, in a simulation chamber. Using state-of-the-art mass spectrometry, we characterized diterpene oxidation products for the first time, and we identified several products with varying oxidation levels, including highly oxygenated organic molecules (HOM) monomers and dimers. The most abundant monomers measured using a nitrate chemical ionization mass spectrometer were C19H28O8 and C20H30O5, and dimers were C38H60O6 and C39H62O6. The exact molar yield of HOM from kaurene ozonolysis was hard to quantify due to uncertainties in both the kaurene and HOM concentrations, but our best estimate was a few percent, which is similar to values reported earlier for many monoterpenes. We also monitored the decrease of the gas-phase oxidation products in response to an increased condensation sink in the chamber to deduce their affinity to condense. The oxygen content was a critical parameter affecting the volatility of products, with 4–5 O-atoms needed for the main monomeric species to condense. Finally, we report on the observed fragmentation and clustering patterns of kaurene in a Vocus proton transfer reaction time-of-flight mass spectrometer. Our findings highlight similarities and differences between diterpenes and smaller terpenes during their atmospheric oxidation, but more studies on different diterpenes are needed for a broader view of their role in atmospheric chemistry.

A Novel Scheme for the Synthesis of 21-Acetoxypregna-1,4,9(11)-triene- 17α,21-diol-3,20-dione from 9α-Hydroxyandrostenedione

2020 ◽  
Vol 16 (5) ◽  
pp. 606-610
Author(s):  
Nguyen T. Diep ◽  
Luu D. Huy
Keyword(s):  
Double Bond ◽  
Chemical Synthesis ◽  
Economic Efficiency ◽  
Final Stage ◽  
Side Chain ◽  
Entire Process ◽  
Drug Synthesis ◽  
First Time

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.

CsOH and its Lighter Homologues – a Comparison

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1229-1236
Author(s):  
Matthias Wörsching ◽  
Constantin Hoch
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Structure Type ◽  
Alkali Metal Hydroxide ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Cesium Hydroxide ◽  
Free Ion ◽  
The One ◽  
First Time

Abstract Cesium hydroxide, CsOH, was for the first time characterised on the basis of single-crystal data. The structure is isotypic to the one of the room-temperature modification of NaOH and can be derived from the NaCl structure type thus allowing the comparison of all alkali metal hydroxide structures. Raman spectroscopic investigations show the hydroxide anion to behave almost as a free ion as in the gas phase. The X-ray investigations indicate possible H atom positions.

scholarly journals A Standardized Method for the Preparation of a Gas Phase Extract of Cigarette Smoke

2016 ◽  
Vol 39 (6) ◽  
pp. 898-902 ◽  
Author(s):  
Tsunehito Higashi ◽  
Yosuke Mai ◽  
Yuichi Mazaki ◽  
Takahiro Horinouchi ◽  
Soichi Miwa
Keyword(s):  
Gas Phase ◽  
Cigarette Smoke ◽  
Standardized Method

Ciliastatic Components in the Gas Phase of Cigarette Smoke

Science ◽  
1966 ◽  
Vol 153 (3741) ◽  
pp. 1248-1250 ◽  
Author(s):  
T. R. Walker ◽  
J. E. Kiefer
Keyword(s):  
Gas Phase ◽  
Cigarette Smoke

Analysis of chlorinated hydrocarbons in gas phase using a portable membrane inlet mass spectrometer

2016 ◽  
Vol 8 (36) ◽  
pp. 6607-6615 ◽  
Author(s):  
Stamatios Giannoukos ◽  
Boris Brkić ◽  
Stephen Taylor
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Gaseous Phase ◽  
Chlorinated Hydrocarbons ◽  
Volatile Chlorinated Hydrocarbons ◽  
First Time

A compact portable membrane inlet mass spectrometer (MIMS) has been used for the first time to detect and monitor, both qualitatively and quantitatively, volatile chlorinated hydrocarbons in the gaseous phase.

Kinetic study on the linalool ozonolysis reaction in the atmosphere

2012 ◽  
Vol 90 (4) ◽  
pp. 353-361 ◽  
Author(s):  
Xiaomin Sun ◽  
Chenxi Zhang ◽  
Yuyang Zhao ◽  
Jing Bai ◽  
Maoxia He
Keyword(s):  
Rate Constants ◽  
Transition State Theory ◽  
State Theory ◽  
Oxidation Products ◽  
Tunneling Effect ◽  
Total Rate ◽  
Variational Transition State Theory ◽  
Atmospheric Lifetime ◽  
Ozone Addition ◽  
First Time

In the atmosphere, linalool ozonolysis will generate a series of oxidation products and then form particles through nucleation. In this study, the linalool ozonolysis mechanisms were studied and some of the main products detected from experiment are verified. The Rice–Ramsperger–Kassel–Marcus (RRKM) theory and the canonical variational transition state theory (CVT) with small curvature tunneling effect (SCT) are used to calculate rate constants over the temperature range of 200∼800 K. The total rate constant for the reaction of ozone with linalool is 4.50 × 10−16 cm3 molecule–l s–l, and the addition of ozone to (CH3)2C=CH– is the main ozone addition position. Furthermore, the Arrhenius formulas are fitted and the lifetimes of reaction species in the troposphere are discussed for the first time. The total atmospheric lifetime of linalool relative to O3 is 2.30 h. The O3-initiated atmospheric lifetimes of P1, P3, and P6 are 2.64 months, 16.67 days, and 15.5 h, respectively.

Sign in / Sign up

Export Citation Format

Share Document