Lung cancer and exposure to man-made vitreous fibers: results from a pooled case-control study in Germany.

BACKGROUND: To investigate the association between lung cancer and occupational exposure to man-made vitreous fibers (MMVF), a pooled analysis of two case-control studies was conducted in the years 1988-1994. METHODS: The case series consisted of 3498 males who were histologically or cytologically verified primary lung cancer cases. 3541 male population controls were drawn at random from the general population and matched to cases by sex, age, and place of residence. To examine the relationship between MMVF and lung cancer we asked all study subjects who worked for at least 6 months as construction and installation workers whether they ever installed or removed insulations and what kind of insulation material they used. RESULTS: Some 304 (8.7%) cases and 170 (4.8%) controls reported to have insulated with glass wool or mineral wool mats. Coded as ever/never exposed, the odds ratio was 1.48 (95% CI: 1.17-1.88), adjusted for smoking and asbestos. To be sure to exclude any confounding effect of asbestos, we tried to identify those cases and controls who insulated with glass wool or mineral wool mats only and never reported any asbestos exposure. For this group we calculated an odds ratio of 1.56 (95% CI: 0.92-2.65), after adjustment for smoking. An elevated risk was also estimated on the basis of an expert rating which was done for a subgroup of cases and controls. Ever exposure to MMVF (but not to asbestos) in this subgroup yielded an odds ratio of 1.30 (95% CI: 0.82-2.07). CONCLUSIONS: Our study provides some indication for an excess risk of man-made vitreous fibers. This result also persists after adjustment for smoking and asbestos.

Dose-response relationship between amphibole fiber lung burden and mesothelioma.

In a mesothelioma case-control study, asbestos and other mineral fibers from lung burden were examined as causal factors. Diagnosis was confirmed by a panel of pathologists. For 66 cases and 66 controls from hospitals in five German towns, lung tissue fiber analysis by transmission electron microscopy was available. Control patients were treated by a surgical lung resection mostly because of lung cancer. For chrysotile and other mineral fibers a significantly increased odds ratio (OR) was not observed. A clear dose-response relationship was demonstrated for the concentration CA of amphibole fibers longer than 5 microm. Between 0.025 and 2.5 fibers/microg dry weight (f/microg) the relationship can be approximated as OR = CA/(0. 025 f/microg). Similar but less distinct dose-response relationships were found in a Canadian and an Australian study. It is concluded that among German mesothelioma patients factors not associated with amphibole fiber concentration are not predominating.

Measurement of inorganic fibrous particulates in ambient air and indoors with the scanning electron microscope.

In the Federal Republic of Germany, the concentration of inorganic fibrous particles in the ambient air is measured by scanning electron microscopy (SEM) in accordance with draft guideline VDI 3492. Fibres of length greater than or equal to 2.5 microns are counted at a magnification of X2000. The concentrations and fibre dimensions of asbestos fibres and other mineral fibres were determined for 231 ambient air samples, 219 indoor air samples taken during asbestos removal and 21 taken at workplaces. In the ambient air measurements in rural and urban areas, the average concentration of other inorganic fibres was greater than 1000 fibres of length greater than or equal to 5 microns per m3. On the average, only about 100 or fewer asbestos fibres of length greater than or equal to 5 microns per m3 were observed. These 'asbestos fibres' from ambient air had low aspect ratios. They differed substantially from asbestos fibres measured in the ambient air close to sources of asbestos emissions, indoors during asbestos removal or at workplaces. Furthermore, the size distribution of these 'asbestos fibres' was similar to that of 'other inorganic fibres'. We suggest, therefore, that a substantial portion of the 'asbestos fibres' observed by SEM analysis in ambient air samples from rural and urban areas should be classified instead as 'other mineral fibres'.

Malignant mesothelioma of tunica vaginalis testis.

A case of biphasic malignant mesothelioma of the tunica vaginalis occurring in a sixty-four-year-old man is described. The tumor metastasized widely and led to the patient's death two and one-half years after diagnosis. Review of the literature revealed 7 cases of malignant mesothelioma of tunica vaginalis. These tumors appeared highly aggressive with early onset of metastasis. Histologically, the tumors may be epithelial, fibrous, or biphasic. In contrast to the benign variants of mesotheliomas, these tumors often show significant nuclear atypia, mitotic activity, and invasion of the epididymis, spermatic cord, lymphatic spaces, or the fibrous tissue of the tunica.

Brenner tumor of the uterus.

Extraovarian Brenner tumors are extremely rare. Three paratesticular lesions have been observed in men. The only extraovarian Brenner tumor in a woman previously reported was located in the broad ligament. This paper describes a small tumor with histologic features of Brenner tumor within the wall of the uterus. The possible histogenesis is briefly discussed.

Morphologic alterations in sheep after implantation of the Akutsu total artificial heart.

The present report describes morphologic alterations produced in sheep after implantation of a four-chambered total artificial heart. Two groups of sheep were studied. The first group was given no special antishock therapy and had an average survival time of 25.8 hours. Major morphologic changes produced in the first group were focal infarction and massive hemorrhage of the large and small bowel, ascites, severely altered lungs and multiple infarcts in the kidneys. The second group of sheep was given antishock therapy and showed an average survival time of 35.4 hours. Severe morphologic alterations in this group were generally absent in all organs except the lungs, which showed varying degrees of congestion, hemorrhage, edema, pneumonitis and atelectasis. Death in both of the above groups was due to development of irreversible hypotension and respiratory failure.