The alveolar basal lamina, which defines the border between the original interstitium and the air space, can be conveniendy and specifically visualized for light microscopy by immunohistochemistry using antibodies directed to its constituent proteins, such as laminin and type IV collagen. It can also be identified by electron microscopy. Cells actively synthesizing connective-tissue proteins can…
Two elements are involved in the repair of tissue injury, the replacement of damaged cells and the filling of spaces that result from tissue loss. The lung, unlike other organs, has an abundance of empty spaces in its normal state and, of course, requires them to function. Many forms of lung injury eventuate in pulmonary…
Recently, a new method for conducting specific inhalation challenges with occupational allergens in particulate form has been described. The particle size of the allergen is first reduced in a cyclone sample mill. The allergen is then placed in a vibrating reservoir, which feeds the allergen onto a rotating disk. The speed with which the allergen…
For instance, it would be inappropriate to challenge a nurse with a drug (in powder form) to which she is exposed at work while measuring small quantities into beakers, by asking her to tip large quantities of the material from 1 container to another. The severity of the response that the subject describes occurring at…
In the tidal breathing method, 10 fold concentration increases are used. The challenge period at each concentration is 5 minutes. This 5-minute period is further divided into 1-, 2- and 2-minute challenges, with 10 minutes between each challenge. The FEV, is measured at the end of each 10-minute rest period before a further challenge is…
Dosimeter Method. The allergen is delivered via a dosimeter to deliver known amounts of allergen during each inspiratory maneuver. The number of inspirations is recorded. Tidal Breathinc Method. The allergen is expressed from a continuous-output nebulizer primed with a fixed volume of allergen solution and delivered via a 500-ml rebreathing bag linked to an oronasal…
Specific Bronchial Hyperresponsiveness Bronchial provocation studies are increasingly performed to establish specific causes of occupational asthma. Unlike the measurement of nonspecific hyperresponsiveness with histamine or methacholine, which is an exceptionally safe procedure, the measurement of specific bronchial responsiveness is potentially dangerous. There are 3 reasons for conducting such an investigation: to document a previously unrecognized…
The PC*, is then determined by logarithmic or linear interpolation between these 2 points. The interpolation may be performed using an algebraic formula or by manually graphing the log dose or dose versus response. These various methods of calculating PC*, have been compared. The differences between PC*, calculated logarithmically or linearly were small (0% to…
The various methods of aerosol generation and inhalation have been compared: the Chai method with the Cockcroft method, the Yan method with the Cockcroft and Chai methods. These studies indicate that bronchial responsiveness can be measured reliably with any of the 3 methods. There are significant differences in the time required to conduct these various…
Cockcroft Method. This method utilizes the same doubling dosage regimen of histamine and methacholine. The aerosol is generated using a Wrights nebulizer primed with 5 ml of test solution and an oxygen flow rate of 7 L/min. It is delivered direcdy into a face mask and inhaled through the mouth (the nose is closed by…
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