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Biomedical subjects

B Gylseth

Publications and source records attributed to B Gylseth.

At least 19 recordsLinked to original sources
PubMed1990

Subacute inhalation toxicity of mineral oils, C15-C20 alkylbenzenes, and polybutene in male rats.

Male Wistar rats were exposed to mist and vapor of two mineral oils, two C15-C20 alkylbenzenes, and one polybutene at aerosol concentrations of 70 mg.m-3 and 700 mg.m-3 for 2 weeks. Of oil mist particles, 82-97 wt% were respirable (less than 4.7 microns). High-level exposure to polybutene was lethal to three of four animals, due to pulmonary edema. Elevated numbers of pulmonary macrophages and increased macrophage vacuolization were observed after exposure to the polybutene, both mineral oils, and one alkylbenzene. The same alkylbenzene produced body weight loss. Deposition analysis was performed for one mineral oil. No oil was detected in brain tissue, while retroperitoneal fat tissue contained 541 (401-702) micrograms oil/g tissue, half of this still present after an exposure-free period of 2 weeks. It is concluded that inhalation of the polybutene and one of the mineral cable oils tested here produces toxic effects in lung.

Adipose Tissue↗
PubMed1986

Occupational exposure and regional variation of malignant mesothelioma in Norway, 1970-79.

This investigation is based on a study of 117 men and 24 women with malignant mesothelioma registered by the Cancer Registry of Norway, 1970-79. The age-adjusted incidence rate in men for each county varied from 1.7 to 13.3 per million per year. Eighty-two percent of the men revealed possible occupational asbestos exposure. They were evenly distributed between counties with high and low mesothelioma incidence. Only 17% of the women had possible occupational asbestos exposure. Total lung fiber concentration was analyzed with scanning electron microscopy in 65 men and 13 women. The median lung fiber concentration in men was 2.4 million per gram of dried tissue (range less than 0.4-490), in women 1.0 million per gram (range less than 0.4-41), and in male controls less than 0.4 million per gram (range less than 0.4-4.8). The median year of first exposure was 1937 (range 1909-60) for men from counties with a high incidence rate and 1945 (range 1938-59) for men from counties with a low incidence rate. The counties with a high compared to a low incidence rate of malignant mesothelioma, 1970-79, showed an apparent difference in the percentage of population employed in industry in 1946. The regional variation in the incidence of malignant mesothelioma in men is mainly attributable to the proportion of population exposed to asbestos in industry per county prior the 1950s and the time since exposure started.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Relation between pathological grading and lung fibre concentration in a patient with asbestosis.

The fibre concentration and extent and severity of fibrosis have been analysed in 48 specimens from the left lung of a patient with asbestosis. Two different methods of fibre analysis were used. The results obtained by transmission electron microscopy were 2-2.5 times higher than those obtained by scanning electron microscopy. Low temperature ashed samples showed on average twice the number of fibres obtained after wet digestion of the samples. The transmission electron microscope detected considerably shorter fibres than the scanning electron microscope. Low temperature ashing produced also shorter fibres compared with the wet digestion procedure. A statistically significant correlation between fibre concentration and the grade of fibrosis was found only for low temperature ashed samples analysed in the transmission electron microscope. When dividing the lung into nine anatomical compartments and pooling the grade of fibrosis and the fibre concentration data within each compartment, an even better correlation was obtained.

Aged↗
PubMed1985

Fiber concentration in lung tissue of patients with malignant mesothelioma. A case-control study.

The risk of malignant mesothelioma associated with low-level asbestos exposure is an important unresolved issue today. We have analyzed the asbestos fiber concentration in lung tissue from 14 cases of malignant mesothelioma and 28 case-matched controls by scanning electron microscopy. The cases represent 86% of all mesotheliomas recorded by the Cancer Registry of Norway from the county of Hordaland between 1970 and 1979. Based on 1 million fibers per g of dried tissue as an indicator of cumulated asbestos exposure, the odds ratio (relative risk) was 8.5 (95% confidence limits, 2.3-31.1). Assuming that the risk of malignant mesothelioma is related to mineral fiber concentration in lung tissue, it is concluded that a fiber concentration exceeding 1 million fibers per g of dried tissue is associated with an increased risk of malignant mesothelioma. Furthermore, the results are consistent with a no-threshold response.

Adult↗
PubMed1985

Analysis of asbestos fibers and asbestos bodies in tissue samples from human lung. An international interlaboratory trial.

In order to compare methods of counting asbestos fibers in lung tissue, seven laboratories participated in an interlaboratory trial in which tissue samples from five human lungs were analyzed. In some laboratories, fiber concentrations were assessed with the light microscope and, in others, with either scanning or transmission electron microscopes. Within each laboratory the ranking of the results was similar, but there were marked differences in the absolute values obtained by the different laboratories. It is concluded that the laboratories participating in this trial appear to produce internally consistent results, but there is difficulty in directly comparing results from one laboratory to the next.

Aged↗
PubMed1985

Mica pneumoconiosis--a literature review.

Sixty-six cases of mica pneumoconiosis have been reported in the literature. Twenty-six of the cases suggest that pneumoconiosis may be caused by pure mica alone. In only six cases the diagnosis was based on clinical examination, radiography, and lung biopsy or autopsy results. In one of these six, doubt was raised by the authors about the purity of the mica exposure. Seven epidemiologic studies have been performed among mica-processing workers, and these studies are all cross-sectional. In addition 30 experimental investigations have been carried out. However, there are no controlled inhalation studies among them. The results from the intratracheal instillation studies do not give a unanimous conclusion as to whether pure mica is fibrogenic or not. Present knowledge suggests that pure mica is moderately toxic and may induce pneumoconiosis. Exposure to mica is usually associated with exposure to other minerals such as quartz and feldspar.

Aluminum Silicates↗
PubMed1984

A striking deposition of mineral particles in the lungs of a farmer: a case report.

The object of this study was to analyze mineral particles in lung tissue from a farmer who underwent lobectomy due to a lung tumor and relate these analytical findings to occupational exposure and histopathological and clinical diagnoses. Despite no clear evidence of previous occupational dust exposure, heavy deposits of birefringent particles and slight pulmonary fibrosis were found during histopathological examination. Extracts from the lung tissue were analyzed by electron microscopy and X-ray microanalysis for mineral particles. The major components of the dust were identified as mica, talc, and silica. Minor components included asbestos fibers and rutile fibers. Some of these fibers were coated by ferroproteins. Mica, quartz, feldspars (plagioclase), and rutile fibers were found in the soil from the farmer's potato storehouse. Based on these findings it is assumed that the slight pulmonary fibrosis is probably caused by the different mineral particles deposited.

Humans↗
PubMed1984

Silicotic lesions of the bone marrow: histopathology and microanalysis.

Silica deposition and characteristic nodular silicotic lesions of the bone marrow, virtually unknown features of silicosis, are described in a case of severe lung silicosis with silicotic granulomas of the liver and spleen. Scanning electron microscopy and X-ray microanalysis confirmed the presence of quartz and feld-spars. The bone marrow lesions included inconspicuous accumulations of silica-containing macrophages, free silica, slight lymphocyte and plasma cell infiltration, and reticulin fibre formation; and development of slightly larger partly fibrous silicotic nodules, comparable to those of the lung, liver, and spleen. Silicosis must therefore be considered in the differential diagnosis of bone marrow granulomas.

Aged↗
PubMed1984

In vitro macrophage cytotoxicity of five calcium silicates.

Five calcium silicate minerals (two naturally occurring and three synthetic compounds) with defined morphology and chemical composition were compared for their cytotoxic and lysosomal enzyme releasing effects on unstimulated mouse peritoneal macrophages in vitro. One synthetic material, a fibrous tobermorite, was cytotoxic towards the cells, and two naturally occurring wollastonites induced selective release of beta-glucuronidase from the cells.

Animals↗
PubMed1984

In vitro cytotoxicity and quantitative silica analysis of diatomaceous earth products.

Mouse peritoneal macrophages were used to evaluate the relative cytotoxicity of a series of diatomaceous earth products in vitro. The amorphous and crystalline silica content of the products was determined by a combination of infrared spectroscopy and x ray powder diffraction techniques. The cytotoxicities of the high cristobalite content flux calcined materials were similar to that of the standard cristobalite ; both the natural and straight calcined materials had significantly greater activities than the flux calcined materials. Thus within the limitations of the macrophage cytotoxicity test the hypothesis that crystalline content is the only determinant of fibrogenicity of diatomaceous earth is not supported.

Animals↗
PubMed1984

Medico-legal aspects of malignant mesothelioma.

The object of this investigation was to discuss medico-legal aspects of malignant mesothelioma in relation to social insurance legislation for occupational injuries and diseases in Norway. During the period 1960-79 the Cancer Registry of Norway recorded a total of 155 men and 35 women with malignant mesothelioma. However, only 21 men and no women were notified to the National Insurance Institution as occupational disease cases before 31 December 1979, in spite of the well established causal association between occupational asbestos exposure and the disease. The investigation is based on these 21 patients. The long latency period from first asbestos exposure until appearance of the disease and the short survival were evident in this study. Furthermore, the legislation and provisions for occupational injuries and diseases in Norway are obviously intended for occupational accidents, and consequently the legal assessment of patients with malignant mesothelioma was complicated. For those notified, the delay in notification was considerable, and only 50% were notified before death. Delay in the claim procedure was also substantial, and few patients survived the claim procedure period. The decisions were not consistent, particularly decisions regarding "the year of injury" and appeared to have been more restrictive during recent years. One of the 21 cases was not accepted as occupational disease, because domestic exposure was considered more probable than occupational exposure.

Aged↗
PubMed1984

Occupational asbestos exposure, lung-fiber concentration and latency time in malignant mesothelioma.

Mineral fiber concentration in lung tissue was analyzed by scanning electron microscopy in 73 males with malignant mesothelioma and in 36 referents who died of cardio- or cerebrovascular diseases. The investigation showed apparent differences in the median lung-fiber concentration between occupational groups with different levels of asbestos exposure, as judged from their occupational history. Thus the mineral fiber content in human lung tissue provides a useful indicator of cumulative asbestos exposure. There was also a statistically significant difference between the median lung-fiber concentration among mesothelioma cases with unlikely or unknown occupational asbestos exposure and the reference group. The latency times in 42 of the cases with definite or probable occupational asbestos exposure showed a log-normal distribution with a median of 37 years and a range of 19-68 years. No statistically significant correlation was found between the logarithm of the latency time and the logarithm of the lung-fiber concentration.

Aged↗
PubMed1984

Occurrence of fibrous sodium aluminumtetrafluoride particles in potrooms of the primary aluminum industry.

Inorganic fibrous particles have been found in the work environment of the primary aluminum industry. Based on scanning electron microscopic analysis, the concentrations ranged from 9 to 720 fibers/cc. The fibers were generally thinner than 0.1 micron in diameter and shorter than 5 microns. By electron microscopy, energy dispersive X-ray microanalysis, and selected area electron diffraction the fibers were identified as sodium aluminumtetrafluoride.

Air Pollutants, Occupational↗
PubMed1983

Fibre type and concentration in the lungs of workers in an asbestos cement factory.

The predominant asbestos fibre type used in the production of asbestos cement is chrysotile. The use of asbestos in relation to fibre type in a Norwegian asbestos cement plant during 1942-80 was 91.7% chrysotile, 3.1% amosite, 4.1% crocidolite, and 1.1% anthophyllite respectively. Electron microscopy and x ray microanalysis of lung tissue samples of asbestos cement workers who had died of malignant pleural mesothelioma or bronchogenic carcinoma showed a completely inverse ratio with regard to fibre type. The percentage of chrysotile asbestos in lung tissue varied between 0% and 9% whereas the corresponding numbers for the amphiboles were 76% and 99%. These differences are discussed with respect to the behaviour of different fibre types in the human body and to the occurrence of malignant mesothelioma in this asbestos cement factory.

Aged↗
PubMed1983

Hemolytic activity of five different calcium silicates.

Mineral characteristics and the in vitro hemolytic activity of three synthetic and two natural calcium silicates (CaSi) are compared. Hemolysis is higher for the synthetic compounds than for the natural ones. The difference is accentuated by weak ultrasonication of the minerals. No variation was observed within the two groups, including both acicular and fibrous forms. Calcium was released from the minerals during storage in Tris-buffered saline. At the same time, hemolysis decreased, and crystallographic alterations occurred in the leached minerals. Treatment of the CaSi with calcium chelators (EGTA and EDTA) did not change hemolytic activity. An increase was observed when 30 mM calcium was added. Hemolysis is related to specific surface areas and the crystalline structure of the minerals. Calcium may also be a contributing factor.

Calcium Chloride↗