Role Of Carbon Monoxide Research Articles

Criteria and methods for evaluation of toxic hazard

Evaluating the toxic hazard of fire gases has been an area of recent interest. Units of measure for toxic hazard based on the concept of dose are presented. The role of carbon monoxide and hydrogen cyanide as principal toxicants in combustion products is reviewed. The importance of the time-related aspects of smoke transport and exposure to the toxicants is discussed.

Carbon Monoxide is Not Responsible for the Cigarette Smoke‐induced Changes in the Pulmonary Metabolism of Arachidonic Acid and Prostaglandin E2

Cigarette smoke is known to interfere with the pulmonary metabolism of arachidonic acid and prostaglandin E2 (PGE2). We investigated the possible role of carbon monoxide in these cigarette smoke-induced alterations. 14C-Arachidonic acid (50 nmol) was infused into the pulmonary circulation of isolated perfused hamster lungs, and the radioactive metabolites in the perfusion effluent, as well as the distribution of incorporated radioactive arachidonic acid within the lung lipids, were analysed. Carbon monoxide, added into the ventilatory air, had no effect on the oxidative metabolism of arachidonic acid or on the distribution of radioactive arachidonic acid within the lung. In addition, carbon monoxide had no effect on the metabolism of PGE2 following infusion of 100 nmol of 14C-PGE2 into the rat pulmonary circulation. The present study suggests that carbon monoxide is not responsible for the cigarette smoke-induced changes in the pulmonary metabolism of arachidonic acid and PGE2.

Carboxyhemoglobin: determination and significance in oxygen transport.

Apart from being the direct cause of quite a few cases of near-fatal poisoning, carbon monoxide is a very common noxious agent functioning as an additional factor in human disease. The extent of the possible role of carbon monoxide in human pathology is demonstrated by the following data from the Diakonessenhuis Groningen, a 400-bed private hospital1. During a five-month period the carboxyhemoglobin fraction (FHbCO) was measured in the blood of all pre-operative patients. In 64.4% of the 1358 cases FHbCO was < 1.5%, in 26.8% it was between 1.5 and 5.0%, in 8.5% between 5.0 and 10.0% and in 0.4% it was > 10%. The highest value measured in this series was 15.5%. Thus it appears that in a considerable number of patients HbCO fractions are present that are of possible pathophysiological significance. This shows the practical importance of the pathophysiology of carboxyhemoglobin and the need for easy and reliable methods for the determination of FHbCO in blood.KeywordsAbsorbance RatioOxygen AffinityTitrimetric MethodIsobestic PointOxygen Dissociation CurveThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Water loss on Venus: The role of carbon monoxide

The abundance of water on Venus is four to five orders of magnitude lower than on the Earth. This difference may reflect initial differences in the bulk volatile contents of the two planets, or may be the result of processes for massive water loss on Venus. A series of thermodynamic calculations are performed on the heterogeneous system C-O-H-N-S, varying C/H upward from its terrestrial value of 0.033 in order to evaluate the extent to which either of these two possibilities may account for the low water content on Venus. Relative abundances of 84 molecular gaseous species are computed as functions of temperature, total pressure, oxygen fugacity, and bulk C/H. As bulk C/H increases, the complement of atmospheric H 2O decreases, but C/H would have to be raised to an improbably high value to account for the low water abundance on Venus by initial deficiency alone. Increasing C/H also results in a rapid increase in CO/H 2O, however, and enhances water loss by the reaction CO + H 2O = CO 2 + H 2 or by reaction of carbon monoxide with the free oxygen liberated by photodissociation of water. Other water loss mechanisms have relied on crustal FeO as an oxygen sink. Such mechanisms, however, should have operated on both Venus and the Earth and may be insufficient to account for the major differences in present H 2O abundance between the two planets. Calculations performed in this study suggest that if the outgassed C/H on Venus was higher than on Earth by even less than a factor of 5, it would have been sufficient to make carbon monoxide competitive with FeO as a sink for oxygen. Together with the lower initial water abundance that follows from a higher C/H, water loss involving CO may have been a major factor in determining the present low abundance of water on Venus.

Cognitive effects of passive smoking.

The cognitive performance of 32 non-smoking subjects was tested on two separate occasions. In one condition subjects performed on a modified Wilkinson auditory detection task and attempted a modified Raven's progressive matrices test whilst sitting in a room with a confederate who was smoking cigarettes. In the second, non-smoky, condition the subjects undertook parallel forms of the two tests but were in a clean environment with the same confederate who did not smoke. The results indicated a significant reduction in performance on both tests in the smoky over the non-smoky condition. Furthermore, the data from the detection task indicated that the confederate had a significant influence on the level of this reduction. Implications of these results are discussed, particularly with respect to the roles of carbon monoxide and of social variables in mediating the performance reduction.

Carbon monoxide and smoking behavior

Abstract This paper reviews the health risks of carbon monoxide and its relationship to smoking behavior. Special emphasis is placed on behavioral determinants of carbon monoxide uptake. The role of carbon monoxide in measurement and modification of smoking risk is also discussed.

The effects of carbon monoxide on the development of atherosclerosis in the White Carneau pigeon

The effects on the extent and severity of atherosclerosis of intermittent exposure to carbon monoxide have been studied in normo- and hypercholesterolaemic White Carneau pigeons. Carbon monoxide had no enhancing effect in normocholesterolaemic birds. In hypercholesterolaemic birds (induced by adding 1% cholesterol to the diet), the severity of coronary artery atherosclerosis was significantly more in birds exposed to carbon monoxide than in nonexposed birds after 52 weeks exposure but not after 84 weeks. The severity of atherosclerosis was related to the degree of hypercholesterolaemia. It is suggested that, in the White Carneau pigeon, exposure to carbon monoxide has an aggravating effect on plasma cholesterol levels which in turn affects the development of the disease. The possible role of carbon monoxide in relation to the development of human arterial disease is discussed.

The role of carbon monoxide in cigarette smoking. I. Carbon monoxide yield from cigarettes.

The carbon monoxide deliveries of 20 major Canadian brands of cigarettes, determined by gas chromatography and using standard smoking conditions, were estimated and found to vary by a factor of about two. The CO yields were found to increase with puff volume and tobacco moisture, decrease with increased paper porosity, but remain essentially constant with puff duration. The data suggest that reduced CO deliveries can be achieved by increasing the cigarette paper porosity. Combustion temperature presumably also influences CO deliveries, but the relative role ascribed to dilution and combustion is not clear. It may be concluded that smokers can lower their CO exposure by reducing their puff volume, smoking cigarettes manufactured from high porosity paper, by taking fewer puffs, and decreasing their tendency to inhale. Since CO and tar deliveries are correlated, these measures would also tend to decrease a smoker's exposure to tar.

The role of carbon monoxide in the ecology of wood-decomposing Hymenomycetes

The role of carbon monoxide in the ecology of wood-decomposing Hymenomycetes

Role of carbon monoxide in coronary disorders.

Role of carbon monoxide in coronary disorders.

Role of carbon monoxide in tobacco poisoning

Nicotine absorbed into the body along with tobacco smoke is a slow-acting poison with late effects, while carbon monoxide produces more rapid effects and leads to asphyxiation.