Fibrous minerals in the lungs of mesothelioma patients: Comparison between data on SEM, TEM, and personal interview information

Abstract

To determine and compare the fiber types and size distributions in the lung tissue of mesothelioma patients in Finland, samples from 29 patients with known work history were analyzed with transmission electron microscopy (TEM) and X-ray microanalysis. Compared with the earlier results using scanning electron microscopy (SEM), the fiber concentrations were about three times as high and ranged from 0.1 million to 5,200 million fibers per gram of dry tissue. In 15 patients (52%), crocidolite/amosite were the dominating fiber types, representing more than 70% of all fibers. Anthophyllite asbestos was the most prevalent fiber type in eight patients (28%), and it was found in the samples of 13 patients (45%). One-half of the anthophyllite fibers were longer than 5 microns, whereas other fiber types were somewhat smaller.

Retention of asbestos fibers in the human body.

“…Anthophyllite fibers (39 x 10' f/g) detected in the lungs of the asbestos product worker were somewhat thicker (median diameter 0.35 pm) and longer (median length 5.4 Pm). The fiber dimensions of the two cases were similar to those of crocidolite and anthophyllite fibers found in larger series of mesothelioma and lung cancer cases (12)(13)(14). The percentage of fibers >5 pm in length was 20% for crocidolite and about 50% for anthophyllite.…”

“…The main storage compartment of fibers in the human body appears to be the lung parenchyma, but high levels of asbestos fibers are also found in pleura, lymph nodes and kidney (1,(9)(10)(11) (12)(13)(14). The selection criteria of known exposures were met for a series of cancer cases who had been heavily exposed to amphibole asbestos several decades ago.…”

Asbestos exposure and pulmonary fiber concentrations of 300 Finnish urban men.

“…The results of the present study support this view. By comparison, chrysotile fibers have accounted for 10% or less of all pulmonary asbestos fibers detected with transmission electron microscopy in studie s of Finnish lung cancer and mesothelioma patients (3,8). The highest concentration of asbestos fibers (163· 10 6 f· g-I for crocidolite) was found in the lungs of a 54-year-old construction worker, who had a history of about 30 years as a shipyard worker (latency time about 30 years from the start of employment).…”

“…Such national reference values are important in Finland, as 40% of the asbestos used during the past several decades consisted of anthophyllite (2), a variety of asbestos of only minor importance in other industrialized countries. There is increasing knowledge on the pulmonary fiber concentrations of Finnish lung cancer and mesothelioma patients, but the number of reference cases representing the general population is small (3)(4)(5).…”

Relative risk of mesothelioma associated with different levels of exposure to asbestos.

“…Fibers were counted both by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the asbestos minerals were identified with X-ray microanalysis (12,16).…”