Primary particles and their agglomerate formation as modifying risk factors of nonfibrous nanosized dust.

The incidence of certain cancers correlates with the number of dust particles in the air. Nanosized particles differ from coarser particles by their increasing tendency to form agglomerates. The dissociation of biodurable agglomerates after deposition in the alveolar region resulted in a higher toxic potential. Biodurable dusts in the urban and workplace environment were analyzed to determine an effect-relevant exposure parameter. The characterization of the dusts relating to their number of primary particles (P(p)) and agglomerates and aggregates (A + A) was performed by electron microscopy. Diesel soot, toner material, and seven further dust samples in the workplace environment are composed of high numbers of nanosized primary particles (<100 nm) per unit mass occurring as larger agglomerates. Primary particles of rock, kaoline, and seven further dusts sampled in the workplace are not nanosized. In a multivariate analysis that predicted lung tumor risk, the mass, volume, and numbers of A + A and P(p) per milligram dust were shown to be relevant parameters. Dose-response relationships revealed an increased tumor risk in rats with higher numbers of P(p) in nanosized dust, which occurs unintentionally in the environment.

Widespread pulmonary granulomatosis following long time intravenous drug abuse--a case report.

Foreign body granulomas in the lungs following acute singular or long time intravenous drug abuse are frequent findings during microscopic investigation of the lungs. Most cases present single granulomas. Cases with multiple foreign body granulomas, already palpable during autopsy and leading to pulmonary granulomatosis with multiple granulomas are less frequent. We report the case of a 32-year old man, dying suddenly and unexpectedly after a well-known history of drug abuse for more than a decade. The granulomas are caused by foreign particle embolization immediately after intravenous injection of not only the drug itself but also of adulterants, e.g. cotton fibers, potato starch or microcrystalline cellulose. At the end, a reduction in the size of the pulmonary bed had occurred followed by pulmonary hypertension. For the first time, lung dust in such a case was characterised by energy dispersive X-ray (EDX).

Inorganic fibres in the lung tissue of Hungarian and German lung cancer patients.

OBJECTIVE: To ascertain the lung burden of asbestos fibres in Hungarian lung cancer patients in comparison with the cumulative asbestos exposure estimated from the occupational history. METHODS: For 25 Hungarian lung cancer patients, lung tissue fibre analysis was performed by scanning transmission electron microscopy (STEM) and counting of ferruginous bodies (FBs) by light microscopy. Cumulative asbestos exposure in fibre-years was assessed from a standardised occupational history using the report "fibre years" of the German Berufsgenossenschaften. RESULTS: Median and maximum concentrations of fibres longer 5 microns per gram dry lung tissue (g dry) were 0.03 and 7.38 million fibres/g dry for chrysotile, 0.00 and 0.21 million fibres/g dry for amphibole and 0.22 and 0.62 million fibres/g dry for other mineral fibres (OMFs). The maximum values were observed in one patient for whom a high asbestos exposure was evident in advance from the occupational history. CONCLUSIONS: In comparison with reference values obtained by the same method for German patients with no indication of workplace asbestos exposure, increased concentrations of more than 0.2 million chrysotile fibres/g dry were obtained for six of the 25 Hungarian patients (24%). For one of them, the second highest estimate of a workplace exposure of 60 fibre-years and the highest tissue concentration of 7.38 million chrysotile fibres/g dry substantiate a high probability of a causal relationship to asbestos. A further comparison can be made with the results for 66 German patients treated by surgical lung resection for a disorder other than mesothelioma, mainly lung cancer. For the Hungarian lung cancer patients, similar amounts of chrysotile but distinctly lower amounts of amphibole fibres and distinctly higher amounts of OMFs were observed. A correlation between exposure estimates from occupational history and concentration of fibres in the lung tissue was observed for amphibole (Spearman: R = 0.66, P < 0.001, Pearson: R = 0.50, P = 0.01) and for chrysotile (Pearson: R = 0.48, P = 0.02).

Pleural mesothelioma associated with indoor pollution of asbestos.

This case report concerns a 46-year-old woman, dying from histologically confirmed diffuse malignant mesothelioma after asbestos exposure, which was only caused by indoor pollution from crocidolite-containing spray asbestos in building materials. There was no other known occupational or environmental asbestos exposure during her life. The lung tissue fibre analysis by light microscopy showed significantly increased concentrations of ferruginous bodies (3162 FB per gram of wet lung tissue). By use of scanning transmission electron microscopy, clearly increased concentrations of amphibole fibres (8.6 x 10(6) fibres longer than 1 microm and 0.6 x 10(6) fibres longer than > or =5 microm per gram dry tissue), mainly classified as crocidolite, were observed. The disease was attributed to indoor exposure to sprayed asbestos, which occurred during her work as a decorator in the studio of a warehouse.

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.

Environmental exposure to tremolite asbestos: pleural mesothelioma in two Turkish workers in Germany.

This report concerns two Turkish immigrant workers, aged 50 and 59, who developed histologically confirmed diffuse malignant mesothelioma in the absence of obvious occupational exposure to asbestos in Germany. Both patients had spent their childhood in central Anatolia, Turkey, where the presence of tremolite asbestos in the environment has been described. In both patients, the lung-dust burden showed a high concentration of amphibole fibers (186 x 10(6) resp. 59 x 10(6) per gram dry tissue), mainly classified as actionolite/tremolite fibers in scanning transmission electron microscopy. In both patients, the disease was thus attributed to early environmental exposure to tremolite asbestos.

Evaluation and application of a plasma ashing method for STEM fiber analysis in human lung tissue.

A preparation technique for fiber analysis in human lung tissue has been developed that involves freeze-drying and low-temperature ashing. Analysis is made in the analytical scanning transmission electron microscope at a magnification of 10,000 x. With the use of a special counting method, the sensitivity is approximately 80,000 fibers per gram dry tissue with lengths less than 5 microns and 40,000 fibers per gram dry tissue with lengths greater than or equal to 5 microns. In spite of the leaching and contamination effects described in the literature--even for chrysotile fibrils taken from the lung, elemental spectra do not differ essentially from the asbestos standard. In order to carry out a complete check of the preparation method, a suspension of standard crocidolite fibers in water was gelatinated. No changes in length, diameter or aspect ratio distribution occurred. After preparation, at least 40% of the fibers were recovered. Compared to the wide range of fiber concentrations observed in human lung tissue, these recovery rates appear adequate for fiber analysis in lung dust for medical or legal purposes. To date, 70 lung dust specimens have been analyzed. These are discussed in the paper.

Potential health risks from the use of fibrous mineral absorption granulates.

Attapulgite (palygorskite) and sepiolite are fibrous clay minerals used commercially as components in a wide variety of products including oil and grease adsorbents, carriers for pharmaceuticals, cosmetics, and pesticides. They are also components of drilling muds and animal litter and they are used as paint thickeners. The current annual worldwide production of these minerals exceeds one million tons. Although fibrous in nature, the fibre length may vary greatly depending on the location of the geological deposits. American attapulgite is short (0.1-2.5 micron in length, median of 0.4 micron) but palygorskite from other parts of the world is much longer (30% longer than 5 micron). Several samples of these materials have been submitted to scanning transmission electron microscopy (STEM). This paper reports the results of microscopic evaluations and makes a comparison with the data from experimental carcinogenicity studies and it is concluded that fibre length is a most important carcinogenic property.

Asbestos dust exposure during brake repair.

About 10,000 tons of chrysotile per year are used in the Federal Republic of Germany for the production of friction materials. During brake repair an unknown number of approximately 300,000 mechanics in automobile service stations are exposed to asbestos dust. In a field study, asbestos fiber concentrations during brake repair were measured. Occupational histories and chest X-rays of brake service mechanics are being examined. Ninety dust measurements in 76 service stations were made by phase contrast microscopy and by scanning transmission electron microscopy. By electron microscopy, extremely fine chrysotile fibers with lengths less than 5 microns were identified in brake drum dust. Fibers with lengths greater than or equal to 5 microns constituted less than 1% of all chrysotile fibers counted in brake drum dust. Short-term asbestos dust exposures were measured by light microscopy in 101 personal samples during blowing out of brakes, and grinding and turning of brake linings. During blowing out of car brakes, as well as during grinding of brake linings, the product of fiber concentration with length greater than 5 microns and sampling time amounted to about 4-5 fibers/ml X min corresponding to a concentration of 10(6) fibers/m3 over 4-5 min. For trucks and buses higher amounts of 5-10 X 10(6) fibers/m3 X min were observed during these operations. From occupational histories of 210 vehicle mechanics, an average duration of employment of mean +/- s = 21 +/- 10 years and a mean cumulative fiber dose of mean +/- s = (0.54 +/- 1.1) X 10(6) fibers/m3 X years were calculated.