Description: Segment 1 Prof. Pepys introduces the subject and explains that asthma caused by extrinsic agents provides researchers with examples for the immunological analysis of allergic reactions in the bronchi. He says he will consider two types of asthmatic reaction: one mediated by the reaginic antibody IgE and one slow-developing. He begins by discussing the first type of immediate allergy in which reaginic Ig antibody is involved. He shows the most accurate method of skin testing for this allergic reaction on a man in the studio (only the back of the man's head and his arm are seen). Photographs of patients' arms are seen the patients have been skin tested for allergies. Pepys points out raised weals on the skin that mean an allergic reaction has taken place and explains the relevance of the IgE antibody. He also describes another allergy test - the bronchial provocation test. He shows the nebulising equipment and explains how to perform the test. Time start: 00:00:00:00 Time end: 00:04:56:17 Length: 00:04:56:17 Segment 2 A graph showing the results of a bronchial provocation test is seen. The results of the same test performed on a patient who has inhaled disodium cromoglycate are seen Pepys explains the results. Next, he shows how to elicit a precipitin-mediated type of allergic reaction. He carries out the intracutaneous procedure on a test subject (again, with back to camera). He explains the reaction to this test, seen in photographs, and discusses the kind of bronchial reaction that occurs to immunological mechanisms of this sort. A chart shows the results of an inhalation test in a subject with pigeon serum preparation. Another chart shows the same test but with the patient inhaling disodium cromoglycate beforehand. There is no bronchial reaction. Time start: 00:04:56:17 Time end: 00:09:47:00 Length: 00:04:50:08 Segment 3 Pepys discusses another patient who has both IgE antibody and precipitating antibody against extracts of Aspergillus fumigatus. Results of an inhalation test are seen. The results of the same test but with the patient having taken corticosteroid drugs are seen. The case study of a patient allergic to house dust and the house dust mite is discussed, the patient having been given corticosteroid drugs as treatment. Results are seen in charts. Allergic reactions to substances such as chemicals, vapours and fumes are then discussed. Pepys describes a patient tested to the salts of platinum, another to fumes from aluminium solder and a third to fumes of toluene diisocyanate. Time start: 00:09:47:00 Time end: 00:14:51:00 Length: 00:05:04:00 Segment 4 Pepys talks about the clinical significance of these findings, explaining that determining the type of asthmatic reaction is important when treating patients. He then says that these findings are pointers as to how researchers must try and examine the role of immunological mechanisms in asthma. Time start: 00:14:51:00 Time end: 00:18:13:19 Length: 00:03:22:19