The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Emphysema is an abnormal, permanent enlargement of the airways responsible for gas-exchange in the lungs. Primary emphysema is commonly linked to a genetic deficiency of the enzyme &agr;1-antitrypsin which is a major component of &agr;1-globulin, a plasma protein. Under normal conditions &agr;1-antitrypsin inhibits the activity of many proteolytic enzymes which breakdown proteins. This results in the increased likelihood of developing emphysema as a result of proteolysis (breakdown) of the lung tissues.
Emphysema begins with destruction of the alveolar septa. This results in "air hunger" characterized by labored or difficult breathing, sometimes accompanied by pain. Although emphysema is genetically linked to deficiency in certain enzymes, the onset and severity of asthmatic symptoms has been definitively linked to irritants and pollutants in the environment. A significantly greater proportion of the individuals manifesting emphysemic symptoms is observed in smokers, populations clustered around industrial complexes, and coal miners.