ISSN:0098-4108    

DOI:10.1080/15287398409530491

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398409530492

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Ozone is one of the most toxic and ubiquitous air pollutants. This review focuses on the toxic effects of ozone in animals and on the similarities and disimilarities between the toxic effects in animals and humans. The molecular basis for the toxicity of ozone is discussed, based on the vigorous oxidizing properties of ozone. Despite the existence of anatomical differences between human, subhuman primate, and dog lungs versus common experimental rodent lungs, the anatomical lesion of ozone inhalation occurs at the functionally equivalent site of the junction between the conducting airway and the respiratory region. Ciliated cells of the upper airways and the type 1 cell of the centriacinar region are most affected. Type 2 cell proliferation is a hallmark of ozone toxicity. A wide variety of biochemical and physiological changes have been noted in several animal species and in humans. Considerable evidence for a free‐radical‐mediated or lipid peroxide‐mediated toxicity is evident, especially in the induction of the glutathione peroxidase system and the protective effects of vitamins C and E. Ozone appears to be a weak mutagen and to produce chromosomal abnormalities. Defects in defense against airborne infection are present in animals, which are more susceptible to airborne infection after ozone exposure. Epidemiological studies, however, fail to detect increased respiratory infections in humans due to ozone. Despite the variety of toxic effects, few qualitative differences between species are apparent; rather, quantitative differences do occur. Ozone may thus be an ideal compound for quantitative extrapolation of toxicity from animals to humans.

ISSN:0098-4108    

DOI:10.1080/15287398409530493

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This overview is based on experimental and epidemiological studies of NOxtoxicity during the past decade. Approximately 130 published studies are cited and about one‐fourth of these are discussed briefly under one of the following headings: acute and subacute studies, chronic low‐level studies, human studies, and special studies. The latter section examines a selection of comparatively unique investigations, including several devoted to the pulmonary uptake and retention of NO2, and several examining the potential tumorigenicity of NO2. For each major section of the overview, a critical evaluation is attempted in terms of the impact of the appropriate studies on the extant NOxtoxicoiogicai data base and on the current and planned air quality standards for NOX.

ISSN:0098-4108    

DOI:10.1080/15287398409530494

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398409530495

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The relationship between structure and function of the pulmonary gas‐exchange apparatus and its comparative aspects is demonstrated in four sections: (1) the lung as gas exchanger, (2) the gas‐exchange structures of the human lung, (3) comparative aspects of structure‐function correlation, and (4) analysis of structure‐function discordancy. Physical activity and body size are described to influence the structural dimensions of the pulmonary gas exchange apparatus in different ways. As far as the inhalation of toxic substances is concerned, different kinds of effects must therefore be taken into consideration, depending on an animal's size and metabolism; hence, experiments of comparative anatomy and physiology are desirable in order to find an appropriate animal model that permits extrapolation to humans.

ISSN:0098-4108    

DOI:10.1080/15287398409530496

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Comparative physiology of mass transport of gases in mammalian lungs is surveyed in terms of the use of experimental mammals in inhalation toxicology. Principles of similarity, scaling, and the relationship of metabolism to body size are touched on, with reference to the wide variability among mammals of similar size. Mechanisms that influence the magnitude and distribution of pulmonary ventilation are reviewed, including mechanical differences associated with variation in body size. More systematic and complete descriptions and understanding are needed. Recent advances in the understanding of gas mixing and transport in airways and in the pulmonary acinus have applications in comparative physiology and inhalation toxicology that are worth exploring.

ISSN:0098-4108    

DOI:10.1080/15287398409530497

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The major physical and chemical processes involved in the transport and absorption of O3or NO2In the lower respiratory tract are discussed. This includes the development of respiratory tract models, flow patterns, and transport in tube networks, the mucous, surfactant, and tissue layers, and chemical reactions and transport of O3or NO2within these layers. Descriptions of the individual processes are simplified and Integrated to illustrate the formulation of dosimetry models. Data from a dosimetry model, formulated from the concepts discussed, are used to illustrate the types of information obtained by modeling.

ISSN:0098-4108    

DOI:10.1080/15287398409530498

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287398409530499

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Morphometric and morphologic methods have been used to evaluate changes in rat lungs caused by the inhalation of a variety of oxidants. Exposure to 100% oxygen causes diffuse pulmonary injury and leads to death after 66–72 h of exposure. The primary insult leading to death in rats exposed to hyperoxia is injury to pulmonary capillary endothelium. Sublethal exposure to hyperoxia was found to cause diffuse injury to all major components of the alveolar septum and was associated with destruction of approximately 50% of the pulmonary capillary endothelial cells. A corresponding decrease in pulmonary capillary surface area and capillary lumen volume also occurred. Exposure to ozone and to nitrogen dioxide in low concentrations did not cause a diffuse injury throughout the alveolar region of the lung, but rather led predominantly to structural alterations in terminal bronchioles and in their adjacent alveoli. Morphometric evaluation of animals exposed to 0.25 ppm ozone and to 2 ppm NO2demonstrated quantitatively and qualitatively similar lesions. These lesions primarily involve Injury and remodelling of the alveolar epithelium. These changes in the alveolar epithelium were also associated with the recruitment of increased numbers of alveolar macrophages to the proximal alveolar region. The different types of lung injury caused by various oxidants are most likely to be related to differences in their reactivity with tissue components and to differences in concentration, distribution, and diffusion characteristics of the oxidant gases.

ISSN:0098-4108    

DOI:10.1080/15287398409530500

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor