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Oxygen Groups (oxygen + groups)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Influence of Dissolved Oxygen Concentration on the Pharmacokinetics of Alcohol in Humans

ALCOHOLISM, Issue 5 2010
In-hwan Baek
Background:, Ethanol oxidation by the microsomal ethanol oxidizing system requires oxygen for alcohol metabolism, and a higher oxygen uptake increases the rate of ethanol oxidation. We investigated the effect of dissolved oxygen on the pharmacokinetics of alcohol in healthy humans (n = 49). The concentrations of dissolved oxygen were 8, 20, and 25 ppm in alcoholic drinks of 240 and 360 ml (19.5% v/v). Methods:, Blood alcohol concentrations (BACs) were determined by converting breath alcohol concentrations. Breath samples were collected every 30 min when the BAC was higher than 0.015%, 20 min at BAC ,0.015%, 10 min at BAC ,0.010%, and 5 min at BAC ,0.006%. Results:, The high dissolved oxygen groups (20, 25 ppm) descended to 0.000% and 0.050% BAC faster than the normal dissolved oxygen groups (8 ppm; p < 0.05). In analyzing pharmacokinetic parameters, AUCinf and Kel of the high oxygen groups were lower than in the normal oxygen group, while Cmax and Tmax were not significantly affected. In a Monte Carlo simulation, the lognormal distribution of mean values of AUCinf and t1/2 was expected to be reduced in the high oxygen group compared to the normal oxygen group. Conclusions:, In conclusion, elevated dissolved oxygen concentrations in alcoholic drinks accelerate the metabolism and elimination of alcohol. Thus, enhanced dissolved oxygen concentrations in alcohol may have a role to play in reducing alcohol-related side effects and accidents. [source]

Effects of isoflurane on nitric oxide metabolism and oxidant status of guinea pig myocardium

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2001
. Durak
Background: Volatile anesthetics (VAs) have been shown to enhance myocardial recovery during reperfusion, the mechanism of which has not been clarified yet. It has been supposed that this effect of VAs may appear through antioxidative mechanisms. Methods: Thirty guinea pigs were used in the study. There were three groups with 10 animals in each: I , control, II , isoflurane+oxygen and III , oxygen. Isoflurane (2.0% v/v) and oxygen (100%) mixture was given to the animals via a face mask in the isoflurane+oxygen group at the rate of 2 l per min for 30 min a day for three consecutive days. In the oxygen group, oxygen alone (100%) was given under the same conditions as in the isoflurane+oxygen group. At the end of the experiments, the animals were killed and their hearts were removed. In the heart tissues, nitric oxide synthase (NOS) activity, nitric oxide (NO) pool (NO,+NO2,) and malondialdehyde (MDA) levels were measured. Results: NOS activity was found to be higher and the NO pool lower in the isoflurane+oxygen group compared with those of control and oxygen groups. In the oxygen group, MDA level was found to be higher compared to the other groups. There was, however, no significant difference between MDA levels of the control and isoflurane+oxygen groups. Conclusion: Our results suggest that isoflurane prevents peroxidation reactions in heart tissue, possibly by scavenging toxic oxygen radicals produced under hyperoxygenation conditions as occurs with general anesthesia. [source]

Alternative type I and I, turn conformations in the ,8/,9 ,-hairpin of human acidic fibroblast growth factor

PROTEIN SCIENCE, Issue 3 2002
Jaewon Kim
Abstract Human acidic fibroblast growth factor (FGF-1) has a ,-trefoil structure, one of the fundamental protein superfolds. The X-ray crystal structures of wild-type and various mutant forms of FGF-1 have been solved in five different space groups: C2, C2221, P21 (four molecules/asu), P21 (three molecules/asu), and P212121. These structures reveal two characteristically different conformations for the ,8/,9 ,-hairpin comprising residue positions 90,94. This region in the wild-type FGF-1 structure (P21, four molecules/asu), a his-tagged His93,Gly mutant (P21, three molecules/asu) and a his-tagged Asn106,Gly mutant (P212121) adopts a 3:5 ,-hairpin known as a type I (1,4) G1 ,-bulge (containing a type I turn). However, a his-tagged form of wild-type FGF-1 (C2221) and a his-tagged Leu44,Phe mutant (C2) adopt a 3:3 ,-hairpin (containing a type I, turn) for this same region. A feature that distinguishes these two types of ,-hairpin structures is the number and location of side chain positions with eclipsed C, and main-chain carbonyl oxygen groups (, , +60°). The effects of glycine mutations upon stability, at positions within the hairpin, have been used to identify the most likely structure in solution. Type I, turns in the structural data bank are quite rare, and a survey of these turns reveals that a large percentage exhibit crystal contacts within 3.0 Å. This suggests that many of the type I, turns in X-ray structures may be adopted due to crystal packing effects. [source]