Biomedical subjects
M L Warnock
Publications and source records attributed to M L Warnock.
Analysis of the cores of asbestos bodies from members of the general population: patients with probable low-degree exposure to asbestos.
Asbestos bodies were isolated from the lungs of 21 patients who had 300 to 9,000 of such bodies/g of lung tissue, a concentration frequently found in manual laborers in the general population who are not primary asbestos workers. All of the 123 bodies examined by electron diffraction produced diffraction patterns consistent with amphibole varieties of asbestos. Electron microprobe analysis (energy dispersive x-ray spectroscopy) of 46 bodies revealed that 38 of the cores were composed of the commercial amphiboles, amosite and crocidolite, whereas only 8 were composed of the noncommercial amphiboles, anthophyllite and tremolite. Review of the occupations of these patients revealed that all but one had blue-collar jobs. For many of these persons, putative sources of asbestos exposure such as construction work could be defined, but for some, the source could not be determined. One woman was apparently exposed to asbestos in the practice of her hobby of ceramics, in which she used anthophyllite-contaminated clay. We concluded that commercial amosite/crocidolite asbestos forms the cores of most asbestos bodies in manual laborers in the general population and that the source is usually occupational.
Numbers of asbestos bodies in urban patients with lung cancer and gastrointestinal cancer and in matched controls.
We compared the numbers of asbestos bodies extracted from the lungs of 103 patients with lung cancer and 50 patients with gastrointestinal malignant neoplasms to the numbers of bodies extracted from lungs of control patients matched for age, sex, smoking habits, and, in some cases, occupation. All patients were urban dwellers over the age of 40 years, and none was a primary asbestos worker. No differences in the counts of asbestos bodies were observed between the tested and control populations. The numbers of asbestos bodies did correlate well with occupation; the highest counts were found in male manual laborers. We conclude that in the urban population studied herein, the numbers of asbestos bodies alone do not correlate with the presence of pulmonary or gastrointestinal carcinoma; however, uncoated asbestos fibers are also known to be present in the lung, and the possibility that such tumors may be related to the numbers of these fibers in lungs remains to be explored.
Analysis of the cores of ferruginous (asbestos) bodies from the general population. III. Patients with environmental exposure.
Typical asbestos bodies visible by light microscopy were isolated from the lungs of 29 persons with fewer than 100 such bodies per gram of lung, a level that is considered indicative of environmental rather than occupational asbestos exposure. Of 144 bodies examined by electron diffraction, 143 contained an amphibole asbestos core and one contained a chrysotile asbestos core. Thirty-five bodies from 21 patients were also analyzed by electron microprobe. Of these, 21 were chemically consistent with amosite or crocidolite asbestos, 13 with anthophyllite asbestos, and one with tremolite asbestos. Certain differences in chemical fiber types between men and women became apparent. Although cores of amosite and crocidolite predominated in men (12 of 14, 86 per cent), anthophyllite and tremolite comprised 57 per cent (12 of 21) of the cores found in women, a statistically significant difference. These differences suggest that the major commerical varieties of amphibole asbestos (amosite and crocidolite) are the source of the fibers in men, whereas in women a major source may be cosmetic talc, which is often contaminated with anthophyllite and tremolite. On the basis of this study and our previous studies, we conclude that almost all typical asbestos bodies from the lungs of the general population contain an amphibole asbestos core.
Analysis of the cores of ferruginous (asbestos) bodies from the general population. II. True asbestos bodies and pseudoasbestos bodies.
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Malignant mesothelioma arising after direct application of asbestos and fiber glass to the pericardium.
A case of mesothelioma, apparently arising in the pericardium, is reported in a patient who, 15 years previously, had been treated for angina pectoris by dusting of the pericardial cavity with a mixture of fibrous dusts. At autopsy, transparent fibers and ferruginous bodies were present within the pericardium. Electron diffraction and microprobe analysis indicated that approximately two thirds of the fibers were tremolite and anthophyllite asbestos, and the remainder, fiber glass. Development of mesothelioma in laboratory animals has been reported after intrapleural deposition of asbestos and other fibers, but in humans, the link between exposure to asbestos and mesothelioma has always been based on epidemiologic data and the retrospective finding of asbestos in tissues. To our knowledge, this is the first example of a malignant mesothelioma in a human associated with direct mesothelial contact with fibrous dusts.
A simple method for preparing ferruginous bodies for electron microscopic examination.
A new method of preparing ferruginous (asbestos) bodies for electron-optical examination is described. Pulmonary tissue is dissolved in bleach and the residue collected on a Millipore filter. The ferruginous bodies are localized by light microscopy, and a portion of the filter containing a body is cut out and mounted on a coated electron microscope grid. The filter is dissolved in acetone vapor in a condensation washer, leaving the bodies, as well as uncoated submicroscopic fibers, on the grid. This method can be used to obtain bodies from the lungs of individuals after all degress of asbestos exposure, but it is particularly useful when dealing with minimally exposed or non-exposed individuals whose lungs contain very few bodies. The procedure allows easy identification of body cores by electron diffraction or electron microprobe analysis.
The significance of pulmonary changes associated with cerebral perfusion with hypoxic blood in monkeys.
Parameters of cerebral and pulmonary function were studied in ten animals whose brains were perfused with hypoxic right atrial blood according to the Moss method. All animals died as a result of cerebral hypoxia at about 95 minutes after the onset of perfusion. Gross pulmonary congestion, edema, and leukocyte plugs occurred in the seven animals breathing spontaneously, but positive pressure ventilation prevented these changes in three. The resumption of cerebral perfusion with oxygenated blood after 30 minutes of the Moss procedure did not prevent the pulmonary changes and, of more importance, did not prevent cerebral swelling and death at about the same time as that of all the other animals. There were no changes in oxygen uptake or in arterial oxygen tension to indicate that progressive pulmonary failure contributed to death. It is concluded that this model produces brain swelling and brain death with incidental pulmonary pathological changes indistinguishable from early findings in hemorrhagic shock models and that the cerebral hypoxic perfusion model in monkeys is not suitable for studying the effects of "shock lung" therapy.
Changes with age in muscular pulmonary arteries.
The mean wall thickness, in relation to the external diameter, of 100 muscular arteries distended by barium gelatin at 100cm H2O pressure was calculated in "normal" lungs from patients who ranged in age from 3 to 79 years. For normal vessels less than 2 mm in diameter the mean was 2.4% of the external diameter. The mean for vessels in the five persons under 40 years was 1.8% but it was 2.8% for the five older individuals. Although this difference may reflect some increased muscularity with age, some of the increment may be related to a reduced distensibility of vessels caused by the accumulation of interstitial fluid, as manifested by increased weight in the older lungs. Intimal fibrosis was found to increase with age but occurred in less than 50% of the vessels measured.
Muscular pulmonary arteries in chronic obstructive lung disease.
The small muscular pulmonary arteries are thought to be normal in obstructive pulmonary disease despite prolonged hypoxic stimulation to medial thickening. Because measurements on nondistended vessels have considerable variability, we reinvestigated the problem by studying the percentage of wall thickness of distended arteries in lungs taken post mortem from 5 asymptomatic emphysematous patients and 11 symptomatic patients with obstructive pulmonary disease. Vessels in the former patients had normal medial thicknesses. In contrast, we found an elevated mean percentage of wall thickness for vessels between 0.3 and 2.0 mm in diameter of 4.46% +/-1.44% (mean +/-SD) for patients with obstructive airways disease. Obstructive pulmonary disease, therefore, produced medial hypertrophy in small muscular arteries similar to that seen in other conditions associated with chronic hypoxia.
Correlation of quantitative asbestos body counts and occupation in urban patients.
Asbestos bodies were quantified in digests of lung from 252 urban patients who were over 40 years of age. Patients were assigned to six occupational categories that had been determined without knowledge of asbestos body counts. Asbestos bodies were present in the lungs of 96% of the total population. Fewer than 12% of the white-collar men and the blue- and white-collar women had more than 100 asbestos bodies per gram of lung, whereas 32% of the blue-collar men not working in steel mills or construction, 45% of steelworkers, and 65% of construction workers had more than 100 asbestos bodies per gram lung. This distribution suggests that almost everyone in our population has some exposure to asbestos, and certain persons are subject to an additional occupational exposure. Whether asbestos bodies in low concentration are related to disease remains to be determined.
Analysis of the cores of ferruginous (asbestos) bodies from the general population. I. Patients with and without lung cancer.
Ferruginous (asbestos) bodies may be found in the lungs of almost everyone in the population, but little information is available as to whether such bodies are nucleated on asbestos or on some other fibrous dust. In this study morphologically "typical" ferruginous bodies were isolated from the lungs of 23 autopsy and surgical patients, none of whom had primary asbestos exposure. Eleven patients had carcinoma of the lung. To determine the nature of the core, 328 bodies were examined by electron diffraction. Of these, 264 (80%) showed the diffraction patterns of amphibole asbestos, whereas six showed the pattern of chrysotile asbestos. No amorphous cores or crystalline nonasbestos cores were identified. Fifty-eight (18%) bodies could not be diffracted because of the thickness of the iron-protein coat. No differences were seen between patients with and without lung cancer. We conclude that typical ferruginous bodies have asbestos cores, which are usually amphibole type. The findings suggest widespread exposure to asbestos dust; occupational histories appeared to indicate the source of exposure in some but not all patients.
Pulmonary tumorlet. A form of peripheral carcinoid.
Twenty cases of pulmonary tumorlet are presented. Approximately one-third of the tumors occurred in lungs severely scarred by bronchiectasis or other inflammatory processes; the other two-thirds were found in lungs with little to no scarring. In the former instances, tumorlets were found in large scars in which identifying architectural features had been destroyed. In the latter, the tumorlets were seen in minute fibrous nodules, surrounding or obliterating small bronchi or bronchioles. Argyrophilic granules were demonstrated in 14 of 15 cases; in the electron microscope these were consistent with neurosecretory granules. Their location, silver staining properties, and ultrastructure suggest that pulmonary tumorlets are minute peripheral carcinoid tumors.
So-called "minute pulmonary chemodectoma": a tumor not related to paragangliomas.
Twenty-six cases of so-called "minute pulmonary chemodectoma" are presented. The patient population showed a marked female preponderance, and there appeared to be an association of the lesion with pulmonary injury from a variety of causes including cardiac failure, chronic bronchitis and emphysema, and thromboemboli. Half the cases had multiple tumors. Microscopically, the tumors consisted of nests of cells in the interstitial tissue near small veins. Argentaffin and argyrophil stains failed to demonstrate cytoplasmic granules in any case. By electron microscopy, the nests were composed of large cells with broadly interdigitating processes connected by many well-formed desmosomes. The cytoplasm was filled with numerous 60-A filaments. The Golgi apparatus was prominent, while other organelles were sparse. No secretory granules were identified. It is concluded that the fine structure and lack of silver-positive granules are inconsistent with the morphology of previously reported paragangliomas, but that there is a resemblance at the light and electron microscopic level to meningeal arachnoed cells and the cells of meningiomas.
Association of asbestos and bronchogenic carcinoma in a population with low asbestos exposure.
Quantitative counts of ferruginous bodies were performed on digests of lungs from 100 control and 30 lung cancer patients. It was found that the lung cancer group had significantly higher levels, although only 1 patient was known to be occupationally exposed to asbestos. It is suggested that even extremely low levels of asbestos exposure may have a carcinogenic effect.
Chronic eosinophilic pneumonia, a manifestation of allergic aspergillosis.
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Primary malignant lymphoma of mandible: report of case.
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Pulmonary complication of heroin intoxication. Aspiration pneumonia and diffuse bronchiectasis.
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