Philip C. Pratt

Asbestos content of lung tissue in asbestos associated diseases: a study of 110 cases.

Diseases associated with asbestos exposure include asbestosis, malignant mesothelioma, carcinoma of the lung, and parietal pleural plaques. In this study the asbestos content of lung tissue was examined in groups of cases representing each of these diseases and in several cases with non-occupational idiopathic pulmonary fibrosis. Asbestos bodies (AB), which are the hallmark of asbestos exposure, were present in the lungs of virtually everyone in the general population and present at increased levels in individuals with asbestos associated diseases. The highest numbers of AB occurred in individuals with asbestosis, all of whom had levels greater than or equal to 2000 ABs/g wet lung tissue. Every case with a content of 100,000 ABs/g or higher had asbestosis. Intermediate levels occurred in individuals with malignant mesothelioma and the lowest levels in patients with parietal pleural plaques. There was no overlap between the asbestos content of lung tissue from patients with asbestosis and those with idiopathic pulmonary fibrosis. Lung cancer was present in half the patients with asbestosis, and the distribution of histological patterns did not differ from that in patients with lung cancer without asbestosis. The asbestos body content in patients with lung cancer was highly variable. Control cases had values within our previously established normal range (0-20 ABs/g). There was a significant correlation (p less than 0.001) between AB counted by light microscope and AB and uncoated fibres counted by scanning electron microscopy. The previous observation that the vast majority of asbestos bodies isolated from human tissues have an amphibole core was confirmed.

Role of conventional chest radiography in diagnosis and exclusion of emphysema

Although recognizing that the subject is controversial, most authors of textbooks about diagnostic radiology conclude that chest radiography is of little value for either confirmation or exclusion of the diagnosis of emphysema. Yet several reports in the literature show a high degree of accuracy in the interpretation of films for presence of this disease. Some of the controversy results from continuing confusion over the current definition of emphysema in terms of lung structure rather than symptoms or physiologic evidence relating to impaired ventilation. Many autopsy studies have shown that emphysema is often present at postmortem examination and can involve as much as 30 percent of the lung tissue, even in subjects with no respiratory symptoms or impairment during life. Since radiographs deal with structure rather than function, interpreters of chest films should have the intention to recognize the presence of structural emphysema. The correct recognition of emphysema is useful even in a patient without symptoms, and the ability to exclude this diagnosis in symptomatic patients is of equal, if not greater value. The degree of success reported in various studies depends upon the criteria used and the strictness applied by the authors in matching their interpretations to the presence or absence of structural emphysema. This review of existing literature deals solely with papers in which radiographic observations have been related to morphologic evidence of emphysema in inflation-fixed autopsy lung specimens. It identifies reasons for discrepancies among reports and emphasizes the very high predictive value of validated radiographic criteria. Applications of radiographic interpretation both for diagnosis and for exclusion of emphysema in clinical situations are described.

Numbers of asbestos bodies on iron-stained tissue sections in relation to asbestos body counts in lung tissue digests

Utilization of tissue digestion techniques has demonstrated the presence of large numbers of asbestos bodies within lungs of persons after occupational exposure to asbestos, and smaller numbers in the vast majority of persons with no identifiable exposure. Because of the wide variability in results of such studies among different observers, the presence of more than one asbestos body on light microscopy has been recommended recently as one of the morphologic requirements (together with peribronchiolar fibrosis) for the tissue diagnosis of asbestosis. However, data that correlate the occurrence of asbestos bodies in paraffin-embedded tissue sections with the quantification of asbestos bodies by tissue digestion techniques have not been available. The authors counted the asbestos bodies in multiple paraffin-embedded sections of lung tissues stained for iron, and compared those numbers with the asbestos body counts determined by hypochlorite digestion of wet formalin-fixed lung tissue in six cases of asbestosis or asbestos-associated neoplasia. When adjustments were made for asbestos body orientation in tissue sections, shrinkage of sections during processing, and conversion of lung volume to wet weight, the agreement between the two techniques was excellent (r = 0.98, P less than 0.001). An average of two asbestos bodies on 2 X 2 cm (4 cm2) iron-stained tissue sections 5 microns thick is equivalent to approximately 200 asbestos bodies per gram of wet fixed lung tissue.

Polysplenia with pulmonary arteriovenous malformations.

SummaryA patient with polysplenia syndrome, dextrocardia, left atrial isomerism, normal great vessel relationships, and no intracardiac shunts developed progressive cyanosis and clubbing. Pulmonary arteriovenous malformations (PAVMs) were diagnosed by angiography and confirmed by lung biopsy. Superior mesenteric arteriogram revealed hypoplasia of the intrahepatic portal vein branches and a portosystemic shunt. The possible etiologies of PAVMs are discussed.

A modern concept of the emphysemas based on correlations of structure and function

Abstract In this review of current concepts regarding the emphysemas, the basic alterations in pulmonary structure and their functional consequences are related to the clinical manifestations, largely on the basis of studies of inflated lungs, which permit orderly description and quantification of the emphysemas. These improvements in methods have led to agreement that emphysema should be defined by structural changes rather than by symptoms of obstruction to expiratory air flow. Because of their fundamental importance in studies of pulmonary structure, the methods for preparing inflated specimens of lung are briefly reviewed: fume fixation and drying, formalin steam fixation, fixation by intrabronchial liquid formalin with hydrostatic pressure maintained, and quick freezing in situ with examination in the frozen state. Topographic studies of the distribution and severity of lesions at the level of the eye or dissecting microscope are accomplished most readily on fume-fixed dried specimens. However, the histologic detail in such preparations is poor because of difficulty in preparing the sections and the poor quality of the staining reaction. Fixation by intrabronchial formalin provides excellent histologic detail but the gross topography is less clear. Examination in the frozen state has great value for certain specific purposes but is impractical for large scale studies.

Scanning Electron Microscopic Study of the Airways in Normal Children and in Patients with Cystic Fibrosis and Other Lung Diseases

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine pulmonary tissue from 9 patients with cystic fibrosis (CF), 12 patients with diseases other than CF, and from two surgically resected specimens with no known airways disease. A region of the human airways, the transition zone, was observed between the end of the terminal bronchiole and the type II alveolar cell lining of the respiratory bronchioles. This region was lined predominantly by nonciliated bronchiolar (NCB) cells. Patients with CF exhibited indistinct transition zones, epidermoid metaplasia, large dilated bronchial glands, copious surface mucus, alveolar destruction, and unusual microvilli; no single lesion specific for cystic fibrosis was identified.

Characterization of three types of chrysotile asbestos after aerosolization

Jeffrey Mine and Coalinga Mine chrysotile, two asbestos samples prepared for experimental research by the National Institute of Environmental Health Sciences, and the UICC B chrysotile reference sample have been characterized in the aerosolized state using gravimetric measurements, light microscopy, scanning electron microscopy, and x-ray energy spectrometry. These methods revealed (1) a greater respirable mass fraction in the Jeffrey and UICC B preparations compared to the Coalinga sample, (2) for fibers greater than 5 microns in length and less than 3 microns in diameter, Jeffrey Mine chrysotile contained a significantly greater fraction of fibers longer than 40 microns in length compared to the UICC B or Coalinga Mine chrysotiles, and (3) Jeffrey and UICC B chrysotile contained no fibers or fiber clusters which exceeded 2 microns in diameter while Coalinga chrysotile contained numerous fibers and fiber clusters which were greater than 2 microns in diameter. The characterization of these chrysotile preparations in the aerosolized state, in particular the Coalinga Mine chrysotile, demonstrated different fiber length and fiber width distributions when compared with previous characterizations of samples that had been dispersed in a liquid medium by ultrasonification. These observations emphasize the importance of determining size distribution of fibers in the aerosolized state for inhalation studies and the size distribution of fibers in a liquid suspension for oral ingestion, instillation, or injection studies. Because of differences in length-width distributions, each of the studied chrysotile preparations would be expected to have different patterns of deposition in the alveolar regions of the lung after an inhalation exposure.

Hyperimmunoglobulinemia E Syndrome: Radiographic Observations

Susceptibility to recurrent staphylococcal cutaneous and respiratory infections beginning in infancy associated with extreme hyperimmunoglobulinemia E is a recently described primary immunodeficiency syndrome. Other clinical features include depressed cellular immunity and deficient antibody formation. Recurrent pneumonia and cyst formation with variable persistence and expansion characterized the radiographic couse in 11 patients. Five cysts resolved with continuous antistaphylococcal therapy; 2 were resected without recurrence; and 4 persisted after surgery and/or antibiotics (2--8 years). The cysts had dense, necrotic surfaces with fibrous walls, eosinophilic and other inflammatory cell infiltrates, and frequent, persistent, bronchial connections. Sinusitis (9/9) and mastoiditis (3/4) were also observed radiographically.

Pathology of tuberculosis.

Most tuberculous infection results from the inhalation of airborne tubercle bacilli, usually in droplet nuclei disseminated by an individual with active pulmonary lesions. The nuclei must be small enough (3-5 CL) to penetrate beyond the ciliated epithelium of bronchi and bronchioles to alveolar ducts or alveoli. Rarely in the United States, but more commonly elsewhere, infection results from ingestion of milk or other material from tuberculous cattle and begins in the intestinal mucosa and mesenteric nodes. Still more rarely, cutaneous infection occurs, especially on the hands of butchers and pathologists. Infection during mouth-to-mouth resuscitation has been reported in recent years. There have been a few reports of infection by the genital route.

Response of pulmonary energy metabolism to phosgene.

Rats were exposed to phosgene at a concentration of 1.0 ppm for 4 hours in a Rochester-type chamber. At intervals thereafter over a 4 day period, lungs were obtained for histological and biochemical assessments. Edema was estimated by histological examination and by measurement of lung wet and dry weights. In parallel studies, pulmonary mitochondrial respiratory activity was measured using Clark oxygen electrodes. The significant reduction in respiratory control index (State 3 respiration/State 4 respiration)found immediately following phosgene exposure coincided with the highest level of % lung water. There was a concomitant decrease of A TP concentration that persisted on the third day after exposure. Na-K-A TPase activity was reduced 1 day after exposure, thus a lowered A TP level preceded a reduction in Na-K-ATPase or sodium pump activity. The reduction in A TP level and Na-K-A TPase activity may play a major role in damage to lung tissue following exposure to phosgene.