From all sudden traumatic deaths in each area, wre selected only 93 victims based on a prospective protocol to assure that lungs were collected in a consistent and unbiased manner in low and high exposure areas. They differ from those not studied in the following aspects: (1) only lungs of young or middle-aged adults were selected; (2) in all of them, it was possible to interview the closest relative and to fill in a standard questionnaire, including information about agriculture-specific work exposures and occupational exposure; (3) drug abuse or other self-destructive behavior was absent; and (4) the lifetime exposure (residence) history was more than the last 5 years before death and coincidence of the residence of the 5 last years of life with the previous residence would be high in polluted and nonpolluted areas (Table 2).
Morphologic Analysis: The obtained lungs were fixed in 10% neutral buffered formaldehyde solution. After that, they were cut into about 1-em parasagittal slices and carefully examined for the presence of gross abnormalities. To avoid suspicion of widespread exposure to respiratory hazards other than outdoor air pollution, 9 of the 93 lungs collected were excluded because macroscopic and microscopic examinations of fixed lung slides indicated severe chronic bronchitis and/or emphysema and were obtained from older patients who were smokers (median age, 54 years). A section of one of the main bronchi and another sample of distal parenchyma (right middle lobe) were embedded in paraffin and processed according to conventional histologic procedures for optical microscopy. In fact, compared with the entire lung, the middle lobe was chosen, because it is prone to receive high levels of deposition because of its peculiar anatomic features. canadian health&care mall
Slides, 5 μm thick, were taken and stained with hematoxylin-eosin. All slides were coded, randomized, and then evaluated by a single observer who did not have access to the code.
Measurements of Proximal Parenchyma (Main Bronchus): Morphometric evaluation of proximal parenchyma was done for the determination of the volume ratio of main bronchus submucosal glands, based on a point-counting procedure, using a reticulated eyepiece containing 100 points attached to an optical microscope. This procedure has been used previously to quantify the degree of secretory hypertrophy-hyperplasia that occurs after chronic inhalational injury. For this purpose, the number of points hitting glands at the level of the main bronchi was determined in eight microscopic fields at a magnification of 40 X.
Table 2—Summary Information on Individuals Included in the Study
|Age, yr at death Mean||31 (1.8)||26(1.6)|
|Time of residence in the study place, yr||17.5||20.0|
|Mean pack-yr smoked (for smokers only)||6.0||8.7|
|% Occupationally exposed||59||46|
|Anthracosis (mean score)||2.33 (0.37)||3.20 (0.32)’|
|Inflammation (mean score)||1.25 (0.11)||1.69 (0.09)!|
|Wall thickness (mean score)||1.37(0.14)||1.81 (0.07)*|
|Hypersecretion (mean score)||0.10 (0.04)||0.23 (0.05)®|
|Gland/wall ratio (mean score)||0.22 (0.01)||0.25 (0.01)|
Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.