| One interesting study is called, "Approaches to | | | | contrasted with the unexposed population. The |
| prevention of asbestos-induced lung disease using | | | | prevalence in the group with direct or indirect asbestos |
| polyethylene glycol (PEG)-conjugated catalase" - | | | | exposure was 5.3, 5.8, 3.5%; whereas in the |
| Journal of Free Radicals in Biology & Medicine - | | | | unexposed population it was 0.34%. These results |
| Volume 2, Issues 5-6, 1986, Pages 335-338 by Brooke | | | | indicate that asbestos is primarily responsible for pleural |
| T. Mossman, Joanne P. Marsh, David Hardwick, | | | | findings, but that some pleural disease may be the |
| Rhonda Gilbert, Scot Hill, Ann Sesko, Marie Shatos, | | | | result of the other factors, still not known. The |
| Jacqueline Doherty, Ann Weller and Michael | | | | identification of other causes is hampered by the long |
| Bergeron. Here is an excerpt: "Abstract - | | | | period which need elapse from the onset of the |
| Asbestos-associated damage to cells of the | | | | process to the radiological appearance of the pleural |
| respiratory tract in vitro can be prevented by the | | | | change." |
| simultaneous addition of scavengers of active oxygen | | | | Another study is called, "Malignant pleural mesothelioma |
| species to cultures. To determine if administration of | | | | caused by environmental exposure to asbestos or |
| scavenger enzymes to animals and humans is a | | | | erionite in rural Turkey: CT findings in 84 patients" by |
| plausible approach to the prevention of | | | | AA Sahin, L Coplu, ZT Selcuk, M Eryilmaz, S Emri, O |
| asbestos-induced lung disease, osmotic pumps were | | | | Akhan and YI Baris Department of Chest Diseases, |
| filled with various concentrations of PEG-coupled | | | | Hacettepe University, School of Medicine, Ankara, |
| catalase and implanted subcutaneously into Fischer | | | | Turkey. - American Journal of Roentgenology, Vol 161, |
| 344 rats over a 28-day period. At 3, 14, and 28 days | | | | 533-537. Here is an excerpt: "OBJECTIVE Malignant |
| after implantation of the pumps, the animals were | | | | pleural mesothelioma in rural Turkey frequently results |
| evaluated for levels of catalase in serum and lung. In | | | | from environmental exposure to tremolite asbestos or |
| addition, lung tissue and lavage fluids were examined | | | | fibrous zeolite (erionite). The aim of this study was to |
| at 28 days for biochemical and morphologic indications | | | | determine the CT features of malignant pleural |
| of cell injury, inflammation, and fibrotic lung disease. At | | | | mesothelioma in patients exposed to asbestos or |
| all time points examined, the administration of | | | | erionite. MATERIALS AND METHODS. The CT scans |
| PEG-catalase caused a dosage-dependent increase in | | | | of 84 patients with proved malignant pleural |
| serum levels of catalase. The levels of lung catalase | | | | mesothelioma were retrospectively evaluated. Twenty |
| were evaluated at 28 days but not at earlier time | | | | patients (24%) had been exposed to erionite and 64 |
| periods. In comparison to control rats, the amounts of | | | | patients (76%) had been exposed to asbestos. The |
| enzymes (lactic dehydrogenase, alkaline phosphatase), | | | | CT scans were interpreted by seven observers who |
| protein, and cells in lavage fluids from treated animals | | | | did not know the clinical or pathologic findings. |
| were unaltered. Moreover, the lungs showed no | | | | RESULTS. CT scans showed either unilateral pleural |
| evidence of inflammation or fibrotic disease as | | | | thickening or pleural nodules/masses in all patients. |
| determined by differential cell counts in lavage and | | | | Pleural nodules were present in 25 patients (30%) and |
| measurement of hydroxyproline. These studies | | | | pleural masses in 44 patients (52%). Pleural effusion |
| suggest that administration of PEG-catalase does not | | | | was found in 61 patients (73%), mediastinal pleural |
| cause injury or other alterations in lung tissue and can | | | | involvement in 78 (93%), pleural calcifications in 52 |
| be pursued as a feasible approach to prevention of | | | | (62%), involvement of the interlobar fissures in 64 |
| asbestosis." | | | | (76%), and volume contraction in 61 (73%). Reduced |
| Another study is called, "Prevalence of pleural | | | | size of the hemithorax was significantly correlated with |
| calcification in persons exposed to asbestos dust, and | | | | chest wall involvement. On the basis of CT findings, |
| in the general population in the same district" - | | | | the preassigned staging was changed in 21 patients |
| Environmental Research - Volume 5, Issue 2, June | | | | (25%), including 44% of the patients with disease that |
| 1972, Pages 210-216 by M. Navrátilb, a and F. | | | | had been classified as stage I. CT findings were not |
| Trippéb, a – Here is an excerpt: "Abstract - It is | | | | significantly different between the patients exposed to |
| of interest whether pleural calcification is primarily the | | | | erionite and those exposed to asbestos. |
| result of long years of exposure to asbestos dust or | | | | CONCLUSION. The most common CT findings in |
| whether there are factors other than exposure to | | | | cases of malignant pleural mesothelioma were |
| dust. We have investigated persons working for a long | | | | unilateral pleural thickening or pleural nodules/masses |
| period in a plant processing asbestos products | | | | with or without effusion. CT provided valuable |
| (chrysotile), persons without occupational exposure to | | | | information on the extent of the disease, which was |
| dust but living in the vicinity of the plant, and | | | | important for staging. Although the CT features are |
| consanguineous relations of patients with pleural | | | | not pathognomonic, they provide valuable clues to the |
| calcifications. We have also studied a large population | | | | diagnosis in patients who have been exposed to |
| above the age of 40, in the district in which the plant is | | | | mineral fibers." |
| situated. Comparison of the groups disclosed that | | | | |
| prevalence of pleural calcifications was closely related | | | | If you found any of these excerpts interesting, please |
| to opportunity for exposure to asbestos dust either | | | | read the studies in their entirety. We all owe a debt |
| occupationally or by family or neighborhood contact, as | | | | of gratitude to these fine researchers. |