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The Relation Between Lung Dust and Lung Pathology in Pneumoconiosis
Abstract
Methods of isolation and analysis of dust from pneumoconiotic lungs are reviewed, and the results of lung dust analyses for different forms of pneumoconiosis are presented.A tentative classification separates beryllium, aluminium, abrasive fume, and asbestos, which cause interstitial or disseminated fibrosis from quartz, coal, haematite, talc, kaolin, and other dusts, which cause a nodular or focal fibrosis which may change to forms with massive lesions. The data suggest that in the first, but not in the second, group the dusts are relatively soluble; only in the second group do amounts of dust and severity of fibrosis go in parallel for a given form of pneumoconiosis. In classical silicosis the quartz percentage is higher and the amount of total dust much lower than in coal-miners' pneumoconiosis. Mixed forms of both groups occur, for instance, in diatomite workers. The need for more research, especially in the first group, is pointed out.
... 24 The cumulative dose of silica (respirable dust concentration multiplied by crystalline silica content and exposure duration) is the most important factor in development of silicosis. 16,[25][26][27][28] Nagelschmidt 28 summarised much of the historical data for the association between weight of silica retained in the lung and increasing pathological grades of silicosis. Positive correlations have also been reported between hydroxyproline (as an index of fi brosis), silica dust content, non-silica inorganic dust, radiographical category of pneumo coniosis, and pathological grade of silicosis in hard-rock miners in Ontario, Canada. ...
... 32 In gold miners or foundry workers exposed to fairly pure silica, total retained silica loads of 1-3 g are suffi cient to cause silicosis. 28 In coal or hematite miners with concomitant exposure to other dusts, the same weight of silica causes few cases of silicosis. 28 In China, tin and tungsten workers have a higher risk of silicosis than do pottery workers for a specifi c exposure level. ...
... 28 In coal or hematite miners with concomitant exposure to other dusts, the same weight of silica causes few cases of silicosis. 28 In China, tin and tungsten workers have a higher risk of silicosis than do pottery workers for a specifi c exposure level. 33 Much higher alumino-silicate occlusion of silica dusts was reported in pottery work sites, suggesting a potential eff ect of crystal surface characteristics. ...
Silicosis is a fibrotic lung disease caused by inhalation of free crystalline silicon dioxide or silica. Occupational exposure to respirable crystalline silica dust particles occurs in many industries. Phagocytosis of crystalline silica in the lung causes lysosomal damage, activating the NALP3 inflammasome and triggering the inflammatory cascade with subsequent fibrosis. Impairment of lung function increases with disease progression, even after the patient is no longer exposed. Diagnosis of silicosis needs carefully documented records of occupational exposure and radiological features, with exclusion of other competing diagnoses. Mycobacterial diseases, airway obstruction, and lung cancer are associated with silica dust exposure. As yet, no curative treatment exists, but comprehensive management strategies help to improve quality of life and slow deterioration. Further efforts are needed for recognition and control of silica hazards, especially in developing countries.
... Exposure to dusts with high content (>18% of the total dust deposited in lung) of free crystalline silica results in classic silicosis, while mixed dust fibrosis develops in the presence of low silica content (<18% of total dust deposited in lung). 42 MDF is seen in silicosis, CWP (coal mine dust lung disease), and other pneumoconioses. The pathology is classified as "mixed dust" when mixed dust lesions have a higher score than other lesions, and as "silicosis" when silicotic nodules have a higher score than other lesions. 2 Mixed dust pneumoconiosis (MDP) is defined pathologically as a pneumoconiosis showing dust macules and/or MDF, with or without silicotic nodules in an individual with a history of exposure to mixed dust. ...
... Irregular opacities seen on radiographic and CT images represented interstitial fibrotic or mixed dust fibrotic changes associated with the accumulation of birefringent particles and emphysematous change, as noted at histologic analysis. 42 In two autopsied cases of MDP studied by us, the common HRCT findings were centrilobular nodules, ground-glass opacities, interlobular septal lines, reticular opacities, emphysematous spaces, and honeycomb cysts. Pathologic examination obtained at autopsy showed macules, MDF, patchy interstitial fibrosis predominantly concentrated around respiratory bronchioles and brown pigmented macrophages, and severe interstitial fibrosis with honeycombing (Fig. 4a-e). ...
The radiological patterns of known pneumoconiosis have been changing in recent years. The basic pathology in pneumoconiosis is the presence of dust macules, mixed dust fibrosis, nodules, diffuse interstitial fibrosis, and progressive massive fibrosis. These pathologic changes can coexist in dust-exposed workers. High resolution CT reflects pathological findings in pneumoconiosis and is useful for the diagnosis. Pneumoconiosis such as silicosis, coal workers' pneumoconiosis, graphite pneumoconiosis, and welder's pneumoconiosis, has predominant nodular HRCT pattern. Diffuse interstitial pulmonary fibrosis is sometimes found in the lungs of this pneumoconiosis. In the early stages of metal lung, such as aluminosis and hard metal lung, centrilobular nodules are predominant findings, and in the advanced stages, reticular opacities are predominant findings. The clinician must understand the spectrum of expected imaging patterns related to known dust exposures and novel exposures. In this article, HRCT and pathologic findings of pneumoconiosis with predominant nodular opacities are shown.
... Occupational exposure to dust in agriculture is associated with numerous lung diseases, including chronic obstructive pulmonary disease, asthma, hypersensitivity pneumonia, cancer, and interstitial lung diseases due to exposures to organic and inorganic dust. Up to 15% of farm dust may be silica, and the majority of this is in respirable size [7,8]. MDP is due to exposure to low quantities of silica dust, and as the silica content of inhaled dust rises, lung findings resemble silicosis rather than MDP [5]. ...
... MDP is due to exposure to low quantities of silica dust, and as the silica content of inhaled dust rises, lung findings resemble silicosis rather than MDP [5]. MDP development is due to inhalation of 10-18% of free silica [7,8]. Most soils contain a large proportion of crystalline silica (quartz) and silicate minerals, and farmers' exposure to silica and silicates in agricultural dust has been linked to MDP [9,10]. ...
Pneumoconiosis is an occupational disease found in workers with environmental exposure to organic and inorganic dust, as in mining, sandblasting, pottery, stone masonry, and farming. The inflammatory response of the lung to respirable dust causes the formation of macules, nodules, and fibrosis, and higher silica content in inhaled dust is associated with increased fibrosis. Mixed dust pneumoconiosis (MDP) is characterized by exposure to dust containing 10-20% silica, and its lung imaging show irregular opacities. Histopathology plays a vital role in the diagnosis of MDP. Though it has a favorable outcome, it evolves slowly over many years of constant exposure and is characterized by worsening dyspnea and cough gradually progressing to cor pulmonale. The only effective treatment is removing exposure, which makes it essential to recognize the disease early for a favorable outcome. We present a case of mixed dust pneumoconiosis in a farmer from South America who had asthma. He presented with worsening dyspnea and multiple nodules in both lungs on imaging and cor pulmonale. An extensive workup was done, and it ruled out any malignancy and tuberculosis. Analysis of video-assisted thoracoscopic surgery (VATS) biopsy samples confirmed the diagnosis of mixed dust pneumoconiosis. He had a confluence of irregular nodes in the upper lobes of the lungs, and the largest was 2.1 cm. This fits the International Labour Organization (ILO) definition of progressive massive fibrosis. This, along with cor pulmonale present in him, gives it a poor prognosis even after he is removed from dust exposure. He received steroids, which led to symptomatic improvement, and he was discharged to follow up with the pulmonologist.
... Although dust exposures are frequently described as occurring "over a working lifetime," in many instances, exposures are intense, and the disease occurs within a shorter time. 35 Reports from the previous century that addressed the total dust burden in the lungs of miners with pneumoconiosis made no distinction of dust between the interstitium, the airway, and the alveolar space. In these reports, incinerating or "ashing" the lung after a sudden death (such as a mine accident) allowed a comparison of total dust to profusion category of pneumoconiosis. ...
... There was little correlation. 35 In these examples, dust in the airway and alveolus, and not in the interstitial space, may well affect the relationship between total dust and the presence and profusion of opacities (Appendix 3, http://links.lww. com/JOM/B165). ...
Objective:
Evaluate the role of whole lung lavage (WLL) in the treatment of pneumoconiosis and compare changes in lung function over time in treated and untreated miners.
Methods:
We systematically reviewed and identified eight controlled studies with a treated and comparison group with lung function tests before WLL and a year or more later. 292 patients were included in our meta-analysis.
Results:
Studies consistently showed a slowing of the rate of lung function decline with WLL at one, two, and four years. In some reports, details of the population under study, reliability of lung function tests, the adequacy of matching, technical aspects of the procedure and adverse effects associated with WLL were not available.
Conclusions:
Despite recognized weaknesses in the presentation of information, this procedure may show promise in altering the natural history of pneumoconiosis.
... Iron compounds are the most common mineral chemicals in nature, and they can be found in different forms, such as forms of Fe (II) and Fe (III) ions (Dahmann et al., 2008;Driscoll et al., 2005;Greenberg et al., 2007). Iron oxides are used as raw materials in metallurgical industries (Stefaniak et al., 2007), and magnetite as iron oxide is widely used in medical care and environmental purification facilities because of its magnetic properties (Basu et al., 2009a;Beamer et al., 2010;Dostert et al., 2008;González and Kamiński, 2011;Kumari et al., 2013;Nagelschmidt, 1960). Iron oxides can be made airborne through natural processes or industrial and mining activities (Harrison et al., 2005). ...
... Magnetite iron oxide is found in nature, industry, and medicine (Basu et al., 2009b;Gieré, 2016;Nagelschmidt, 1960), but its health effects are unclear and contradictory (El Mallakh, 2015; Bourgkard et al., 2008; Harrison et al., 2005;Moulin et al., 2000;Su et al., 2011). The results of this study showed that the nano-size and higher concentrations of magnetite iron oxide particles and the longer exposure durations are toxic factors for the A 549 cell line. ...
Introduction: Magnetite as iron oxide is widely used in industries and used for medical care due to its magnetic property. The environmental and occupational exposure to airborne nano and microparticles of iron oxides compounds are reported. Since there are some contradictory toxicological reports for the nano and micro sizes of the magnetite particles, the objective of this study was to investigate the effect of particle size in their toxicities.
Methods: The human cell line A549 was exposed with magnetite iron oxide in two size categories of micro (≥5µ) and nano(<100 nm), with four concentrations of 10, 50, 100 and 250 µg/ml in two time periods 24 and 72 hours. The cell viability, reactive oxygen species, potential changes of cellular membrane and incident of apoptosis were studied.
Results: Nano and micro magnetite particles demonstrated diverse toxicity effects on the A549 cell line for the 24 and 72 hour exposure periods, however, the effects produced were time and concentration dependent. Nano magnetite particles produced higher cellular toxicities in form of decreased viabilities in the concentration exposure higher than 50 µg/ml (p<0.05), along with increased ROS (p<0.05), decreased cellular potential membrane (p<0.05) and reduced rate of apoptosis (p<0.05).
Discussion: The results of this study demonstrated that magnetite iron in nano range sizes had increased absorbability for the A549 cell line than micro sizes and, the same time nanoparticles were more toxic than microparticles demonstrating higher production of ROS and decreased viabilities. Considering higher toxicity of nanoparticles of magnetite iron in this study, thorough precautionary control measures must be considered for their use in the industries.
... 2,3 While some others believed the trace metals found on silica dusts played the major role in silicosis pathogenesis. 4,5 Risk of lung cancer is 3 folds more in silicosis than in general population. 6 Patients with silicosis are 20-30 folds more susceptible to pulmonary tuberculosis. ...
... The interleukin-4 and the growth factors stimulate fibroblasts to proliferate and produce collagen around the silica particle, thus resulting in fibrosis and the formation of nodular lesions. 3,4 In this report, our patient with a typical occupational history of stone mining for a decade and chest imaging result was diagnosed silicosis by definite histopathology result. ...
PRESENTATION OF CASE
A 45 years old male who used to work as a stone miner in
Potka Block of East Singhbhum for 20 years complained of
dry cough, shortness of breath, dyspnoea and severe weight
loss for months and worsen 5 days before admission at MGM
Medical College. At the time of admission, patient was
dyspnoeic even at rest. He had also pedal oedema. Patient
reported a smoking history of 30 years. In the meantime,
patient died due to respiratory failure. For exact diagnosis,
the post-mortem of the patient was done under a board of
three doctors.
... Pathogenesis of silica deposits to the lung has been widely studied, however, with no conclusive mechanism being reached. Some believed the silica deposits could cause immune response which was responsible for silicosis progression [4,5] while some others believed the trace metals found on silica dusts played the major role in silicosis pathogenesis [6,7]. Later the detection of micro-organisms attached to the silica dust suggested another possibility that the onset and progression of silicosis might be determined by the micro-organisms [8][9][10]. ...
... Moreover, trace metals attached to the silica dusts may also influence the damage to lung tissue of the silica dusts and determine the onset and progression of silicosis. Previous reports showed that the gold or foundry miners needed less silica to get silicosis than those who exposed to pure silica [6] and the importance of trace metals in silicosis pathogenesis was later confirmed by studies in Chinese tin and tungsten workers [16]. In addition, micro-organisms such as tuberculosis bacilli attached to the silica dusts may also contribute to the pathogenesis and progression of silicosis, which was reported earlier [8][9][10]. ...
The working environment of stone miners has been believed to cause their susceptibility to respiratory diseases. Silicosis is an occupational disease caused by exposure to crystalline silica dust which is marked by inflammation and scarring in the lung. The immune system boosted after the silica invasion led to self-damage and lay the foundation of silicosis pathogenesis. Silicosis coexisting with other diseases in one patient has been reported, however, was not reported to coexist with constrictive pericarditis. We, for the first time, reported a patient with silicosis and constrictive pericarditis and thought the immune response was probably the link between the two.
A 59-year-old Chinese stone miner complained of chest distress was found to have lung nodules which were found to be silica deposits by biopsy. This patient was also found to have constrictive pericarditis at the same time. Later surgical decortication cured his symptoms.
We provided the first case having constrictive pericarditis concomitant with silicosis. A probable link between the two diseases was the immune response boosted by the silica deposits.
... The occupations of the patients were too various to statistically analyze. The occupations of the patients in the group of UIP were manufacturing industry worker (11), office worker (8), farmer (4), driver (3), teacher (1), merchant (1), guard (1), welder (1), construction industry worker (1), quarryman (1), housewife (12), and unknown (6). The occupations of the patients in the group of NSIP were housewife (12), manufacturing industry worker (2), office worker (1), merchant (1), and unknown (6). ...
... The occupations of the patients in the group of UIP were manufacturing industry worker (11), office worker (8), farmer (4), driver (3), teacher (1), merchant (1), guard (1), welder (1), construction industry worker (1), quarryman (1), housewife (12), and unknown (6). The occupations of the patients in the group of NSIP were housewife (12), manufacturing industry worker (2), office worker (1), merchant (1), and unknown (6). The occupations of the patients in the BOOP group were merchant (2), office worker (2), construction industry worker (2), housewife (2), and unknown (5). ...
Background and aim: Although there is increasing evidence that inhaled birefringent particles (BPs) cause pulmonary fibrotic reaction, the relationship between BPs and diffuse interstitial lung diseases (DILDs) remains unclear. Methods: We assessed 85 cases of interstitial lung diseases including 50 cases of usual interstitial pneumonia (UIP), 22 cases of nonspecific interstitial pneumonia (NSIP) and 13 cases of bronchiolitis obliterans-organizing pneumonia (BOOP) and 55 cases of normal lung tissue from control group. BPs were measured and counted by image analyzer under polarizing microscope. Results: The average BP count in all types of interstitial lung disease was 223.60/10 high power fields (HPF), significantly higher than the average of 116.80/10HPFs found in the control group (P= 0.01). Among individual disease entities, UIP showed significantly higher BP count than control (232.80/10HPFs, P= 0.01). Although statistically insignificant, NSIP and BOOP also revealed higher BP counts than the control (192.09/10HPFs and 241.54/10HPFs, respectively). Conclusions: Increased BPs in the lung might be related to the fibrogenic process of interstitial lung diseases.
... 53 Combining results from several studies of classical silicosis among miners, Nagelschmidt and colleagues showed a correlation between the mass of quartz in the lung (in grams) and the severity of fibrosis. 55 Quartz as a percentage of total lung dust ranged from 20% upward. The authors noted the quartz content associated with rapidly developing silicosis might be higher, above 30%, and total lung dust content higher than with classical silicosis. ...
Background
With increasing reports of accelerated and acute silicosis, PMF, and autoimmune disease among coal miners and silica‐exposed countertop workers, we present previously incompletely‐described pulmonary pathology of accelerated silicosis and correlations with mineralogy, radiography, and disease progression in 46 Texas oilfield pipe sandblasters who were biopsied between 1988 and 1995.
Methods
Worker examinations included pulmonary function tests, chest X‐ray (CXR), high‐resolution computed tomography (HRCT), and Gallium‐67 scans. Quantitative mineralogic analysis of pulmonary parenchymal burden of silica, silicates, and metal particles used scanning electron microscopy with energy dispersive x‐ray spectroscopy (SEM EDS).
Results
Workers had clinical deterioration after <10 years exposure in dusty workplaces. Although initial CXR was normal in 54%, Gallium‐67 scans were positive in 68% of those with normal CXR, indicating pulmonary inflammation. The histology of accelerated silicosis is diffuse interstitial infiltration of macrophages filled with weakly birefringent particles with or without silicotic nodules or alveolar proteinosis. Lung silica concentrations were among the highest in our database, showing a dose–response relationship with CXR, HRCT, and pathologic changes (macrophages, fibrosis, and silicotic nodules). Radiographic scores and diffusing capacity worsened during observation. Silica exposure was intensified, patients presented younger, with shorter exposure, more severe clinical abnormalities, higher lung particle burdens, and more rapid progression in a subset of patients exposed to recycled blasting sand.
Conclusions
Accelerated silicosis may present with a normal CXR despite significant histopathology. Multivariable analyses showed silica, and not other particles, is the driver of observed radiologic, physiologic, and histologic outcomes. Eliminating this preventable disease requires higher physician, public health, and societal awareness.
... In our The total dose of silica is the main risk factor for the development of silicosis [10]. Nagelschmidt [11] previously reported that a total retained silica dose of 1-3 g was sufficient to cause silicosis. Denim sandblasting, in unregistered facilities, using non-standardized materials, under poorly ventilated circumstances, and without personal protection will definitely cause silicosis. ...
Objective:
This study aimed to review the risk factors for silicosis together with survival analysis and a perspective for lung transplantation with data from a single center.
Material and methods:
We reviewed the medical records of denim sandblasters who were referred to our center between January 2006 and December 2011 and evaluated 219 patients with a history of denim sandblasting with a minimum follow-up period of 5 years until 2016. We analyzed several personal and occupational features, together with functional and radiologic data.
Results:
Of the 219 denim sandblasters, 107 (49%) had been diagnosed with silicosis. In the logistic regression analysis, the duration of exposure was the only independent risk factor for the development of silicosis, indicating a 9% increased risk of silicosis for every month of exposure (p<0.001; odds ratio 1.09; 95% confidence interval 1.050-1.132). Of the patients, 7 (3%) died. A forced expiratory volume in the first second of <44% and a forced vital capacity of <47% were associated with an increased risk of mortality. Mortality was significantly higher in the international labor office category 3 patients, and 5-year survival rates of patients with A, B, and C lung opacities were 88%, 67%, and 25%, respectively.
Conclusion:
Silicosis still kills young workers. Severe radiologic involvement and decreased lung volumes are related to mortality, and lung transplantation is the only therapeutic option.
... ② 화학적 구성 성분 콘크리트의 물질시료 분말에 대한 화학적 구성성 분을 파악하기 위하여 X-선 형광분광기(X-ray Fluorescence Spectrometer, XRF, Model PW2400, Philips, 9.7%, 규소 3.7% 등으로 이루어져 있었다 (Table 1). (Nagleschmidt, 1960;IARC, 1997 (Kim et al., 1998;Kim et al., 1999)도 수 행된 바 있지만 FTIR을 이용한 석영 농도에 대한 연 구가 대부분 이다 (Choi et al., 1987;Jeong et al., 1989;Song & Lee, 1994;Jeong et al., 1995;Phee et al., 1997;Ko et al., 2002 ...
This study was conducted to estimate quartz concentrations in the airborne respirable dust from concrete manufacturing
industries and to compare performance of two analytical methods, direct on filter(DOF) and the transfer methods in the
Fourier Transform Infrared Spectroscopy(FTIR).
Methods: Total 36 area samples were collected from 8 concrete manufacturing industries. Each respirable dust sample was collected
by a 25 mm cassette attached to a 10 mm Dorr-Oliver nylon cyclone. The quartz content was estimated using the intensity of the
absorption peak of quartz at 799 cm
-1
by FTIR.
Results: By the comparison of quartz content in respirable dust between the two methods, the results of using DOF method were higher
than that of transfer method. And the result of quartz concentrations in respirable dust estimated by DOF method were mostly
higher than those by transfer method. Statistically significant difference of quartz concentrations in respirable dust were not found in
shakeout, input, loading and transporting processes by two methods. But quartz concentrations in the molding process had the
statistically significant difference between DOF and transfer method.
Conclusions: The results of the study is suggested that, it be needed to correct the influence of the interferences in order to establish
the DOF method when interfering minerals have an effect on quantitative analysis of quartz in respirable dust by the direct on
filter method with FTIR.
... As the silica concentration increases, the histopathologic picture tends to mimic that of classical silicosis rather than MDP [19]. A component in the mixture of 10% free silica was first suggested as a threshold for the development of MDP [21]; this threshold was later revised to 18% [22]. ...
Background:
Mixed-dust pneumoconiosis (MDP) is a controversial disease with respect to diagnostic criteria. Usually, it is regarded as an occupational disease, but cases due to domestic exposure have been reported. In domestic settings, different dust sources may contribute individually or collectively to the pathogenesis.
Case presentation:
A 56-year-old woman presented with chest nodularity on chest X-ray examination that had not resolved after 6 months of tuberculosis (TB) treatment. Her history showed significant exposure to mixed dusts caused by grinding grains with stones and the use of biomass fuel.
Conclusion:
In residential settings, sufficient exposure to a variety of dusts, primarily silica-based dusts as well as those containing other less-fibrogenic materials, such as carbon, silicates and iron, have been shown to cause mixed-dust pneumoconiosis. In settings where the incidence of TB is very high, such as South Africa, the diagnosis of MDP might be overlooked due to the similarities of both diseases in their radiological presentations, especially when a detailed history of domestic exposure is omitted.
... Sin embargo, de forma simultánea a esta reducción, asistimos en los últimos años a la presentación de casos de silicosis en sectores distintos de los tradicionales y hasta ahora desconocidos, como el de los trabajadores con conglomerados artificiales de cuarzo 6,7 . Estos conglomerados están compuestos de elevadas concentraciones de sílice cristalina y al manipularlos inadecuadamente permiten suspensión de dióxido de silicio (SiO 2 ) en partículas respirables que penetran hasta los alvéolos pulmonares Los datos sobre la historia natural de la silicosis y la validez de las diferentes herramientas diagnósticas proceden en su mayoría de los estudios realizados en minería de interior, canteras de granito, pizarra y fundiciones 8,9 . Hasta la fecha, solo se han publicado series de un escaso número de casos en silicosis asociada a la manipulación de conglomerados de cuarzo 10 . ...
Resumen
Introducción
La silicosis es una enfermedad crónica progresiva producida por la inhalación de sílice cristalina. La mayoría de los casos aparecen en trabajadores de minería de interior y extracción de piedra natural (pizarra, granito). Ante la progresiva aparición de nuevos casos de silicosis en trabajadores con conglomerados artificiales de cuarzo (CAC), se planteó un estudio que tuvo como objetivo analizar las características de la silicosis producida por un nuevo agente en España.
Métodos
El estudio consistió en una serie de 96 casos diagnosticados de silicosis según criterios internacionales durante el periodo comprendido entre 2010 y 2017. Se analizaron las características clínicas, radiológicas, funcionales y patológicas.
Resultados
La edad media fue de 45 años, el 55% con silicosis simple y el 45% con silicosis complicada. En 10 pacientes se diagnosticó silicosis acelerada, con una media de 33 años de edad. El tiempo medio de exposición a los conglomerados fue de 15 años y en un 77% no se utilizaban medidas de protección adecuadas. La mitad de los pacientes estaban asintomáticos y presentaban diferentes formas clásicas en la radiografía de tórax y tomografía computarizada de alta resolución de tórax, así como imágenes de vidrio deslustrado. No se observaron alteraciones en la función pulmonar.
Conclusiones
La silicosis en los trabajadores con CAC se observa en personas jóvenes, en activo, en un considerable porcentaje de forma acelerada, con escasos síntomas y sin alteración funcional. Las medidas de protección son escasas. Es importante conocer estas características para el diagnóstico precoz y las necesarias medidas preventivas.
... For example, different admixtures in dust can alter the biological activity of the silica particles (1,(34)(35)(36)(37)(38). While crystalline structure has long been accepted as conferring toxicity on silica (39,40), recent research suggests that the number and distribution of silanol and siloxane groups rather than crystallinity feature as the primary toxic factors (41). ...
Exposure to silica and the consequent development of silicosis are well-known health problems in countries with mining and other dust producing industries. Apart from its direct fibrotic effect on lung tissue, chronic and immunomodulatory character of silica causes susceptibility to tuberculosis (TB) leading to a significantly higher TB incidence in silica-exposed populations. The presence of silica particles in the lung and silicosis may facilitate initiation of tuberculous infection and progression to active TB, and exacerbate the course and outcome of TB, including prognosis and survival. However, the exact mechanisms of the involvement of silica in the pathological processes during mycobacterial infection are not yet fully understood. In this review, we focus on the host's immunological response to both silica and Mycobacterium tuberculosis, on agents of innate and adaptive immunity, and particularly on silica-induced immunological modifications in co-exposure that influence disease pathogenesis. We review what is known about the impact of silica and Mycobacterium tuberculosis or their co-exposure on the host's immune system, especially an impact that goes beyond an exclusive focus on macrophages as the first line of the defense. In both silicosis and TB, acquired immunity plays a major role in the restriction and/or elimination of pathogenic agents. Further research is needed to determine the effects of silica in adaptive immunity and in the pathogenesis of TB.
... However, inhalation ofdust mixtures by rats led to fibrosis only when airborne and lung dusts contained 20% or more of quartz (3). Similarly, in humans, typical silicotic change with massive fibrosis was observed when the level of quartz in lung dust generally exceeded 18% (4). ...
... In our The total dose of silica is the main risk factor for the development of silicosis [10]. Nagelschmidt [11] previously reported that a total retained silica dose of 1-3 g was sufficient to cause silicosis. Denim sandblasting, in unregistered facilities, using non-standardized materials, under poorly ventilated circumstances, and without personal protection will definitely cause silicosis. ...
... Pneumoconiosis is a medical condition caused by dust in the lungs, for instance, as evidenced by X-ray, computerised tomography (CT) scan or histology, and may be for example due to exposure to silica, mixed dusts, metals [2][3][4], or organic matter. It is modulated by host factors such as genetics, the immune response and smoking [5]. ...
This paper summarises the increasing epidemiological and experimental evidence of the causal link between exposure to high concentrations of welding fume exposure for prolonged periods of time and the subsequent development of pulmonary fibrosis in a relatively small number of people. It is not yet clear which components of welding fume or gases are the cause but the most likely culprits are the soluble transition metals which may cause the formation of free radicals. The most likely work scenario leading to pulmonary fibrosis due to welding fume is of high fume exposure, without effective local extraction and respiratory protection, in confined spaces for long periods of time. Avoidance of high exposures for long periods of time is required to prevent this condition. For clarity the term “pulmonary fibrosis due to prolonged exposure to welding fume at high concentration” is suggested when there is shown to be a causal link in an individual and we recommend that the terms siderofibrosis and arc welder’s lung are abandoned.
http://link.springer.com/article/10.1007/s40194-015-0283-7?wt_mc=internal.event.1.SEM.ArticleAuthorOnlineFirst
... When studying silica dust retained in the lung, it is important to know whether the composition of the dust has been altered by the digestion method used to isolate it from lung tissue. Some studies suggest that lung tissue digestion methods, using acids, alkalis, or heat, alter the composition of silica dust retained in the lung [15,23,33,34]. ...
There is an association between exposure to silica dust and the development of silicosis. Studies have shown that the weight of silica dust retained in the lung is related to the presence and severity of silicosis. To study the dust retained in the lung a method of isolating it is required. Some studies suggest that lung tissue digestion methods, using acids, alkalis, or heat, alter the composition of silica dust retained in the lung. This study aimed to investigate whether methods used to digest lung tissue and isolate the retained dust are suitable for midsagittal sections of lung from deceased South African gold miners with silicosis. Ten methods were identified to digest lung tissue in the literature. Seven of these methods were carried out
on midsagittal lung sections from cases with either moderate or marked silicosis. Of these, four methods digested a substantial portion of the lung tissue. Digestion using 30 % H2O2 with the addition of chloroform lipid extraction yielded the most complete lung tissue digestion. The composition of standard silica (NIST 1878a) was not altered using 30 % H2O2 and chloroform, but minor changes to the background silver filter were noted using X-ray powder diffractometry (XRD). The use of 11.3N HCl, 25 % NaOH, and 40 % KOH altered the composition of NIST 1878a. The composition of three
NIST 1878a samples, placed in a muffle furnace at 380�C for 2 h was also compared to untreated NIST 1878a, and found to be unaltered. A method to rapidly digest a midsagittal section of lung has been developed. It has been shown that isolating dust using this method does not alter its composition.
... Although the radiographic characteristics of mixed dust fibrosis have not been a subject of interest in recent literature, this entity is frequently described in pathology textbooks and is of some clinical importance within the context of lung damage in silica-exposed workers (Gibbs and Wagner 1998;Weill et al. 1994). Exposure to high content (more than 18% of total dust deposited in lung) of free crystalline silica results in classic silicosis, while mixed dust fibrosis develops in the presence of low silica content (less than 18% of total dust deposited in lung) (Nagelschmidt 1960), particularly with simultaneous inhalation of other minerals such as non-fibrous silicate (mica, kaolin, coal, talc, fuller's earth, etc.). These non-fibrous silicates augment the strong fibrotic effect of crystalline silica (Gibbs and Wagner 1998). ...
... T here is a relationship between the content of crystalline silica in exposed dust and resultant pulmonary lesions in pneumoconiosis. 1 When the dust is mainly crystalline silica, the fibrotic lesions are typical silicotic nodules. However, when the dust contains crystalline silica and less fibrogenic nonfibrous silicate, both silicotic nodules and mixed-dust nodules coexist. 2 For this condition, the term mixeddust pneumoconiosis is proposed. ...
Increased prevalence of chronic interstitial pneumonia (CIP) is reported in dust-exposed subjects. We investigated the prevalence of CIP in silicosis and mixed-dust pneumoconiosis and sought morphologic differences of CIP between the pneumoconiosis and idiopathic pulmonary fibrosis (IPF).
We reviewed CT scans of 243 silicosis and mixed-dust pneumoconiosis patients to identify any cases of parenchymal lung lesions showing a CIP pattern, and compared the CT findings with those of 62 patients with IPF. Two observers independently scored CT images and classified the CT pattern as typical or not typical for IPF. Differences were sought between the groups using a nonparametric test, Fisher exact test, and a logistic regression analysis. A radiopathologic correlation was performed in 11 pneumoconiosis patients.
Twenty-eight patients (11.5%) showed CIP on CT. Seven patients (25%) showed a pattern not typical of IPF, while the remaining patients showed a pattern typical of IPF, 11 of which were confirmed pathologically. The extent of fibrosis did not differ between the groups; however, patients with pneumoconiosis showed less traction bronchiectasis (odds ratio [OR], 0.19; 95% confidence interval [CI], 0.08 to 0.48; p < 0.001), more subpleural homogeneous attenuation (OR, 2.56; 95% CI, 1.55 to 4.23; p < 0.001), and fibrosis was more randomly distributed (OR, 315.38; 95% CI, 4.68 to 21244.63; p = 0.007). Pathologically, subpleural homogeneous attenuation corresponded to dense fibrosis often with abundant silicotic nodules.
Prevalence of CIP in pneumoconiosis was approximately 12% on CT. One fourth of patients showed an atypical IPF pattern, and the others showed a typical IPF pattern.
... Exposure to cosmetic grade talc as used in cosmetic and health care products is infrequent and of short duration. Published cases of talc pneumoconiosis, therefore, primarily concern subjects engaged in the mining or processing of talc and usually refer to data obtained before modern mining and environmental standards were implemented (Dreessen, 1933; Dreessen and Dalla Valle, 1935; Porro, Patton, and Hobbs, 1942; Greenburg, 1947; Millman, 1947; Hogueand Mallette, 1949; McLaughlin, 1950; Jaques and Benirschke, 1952; Alivisatos, Pontikakis, and Terzis, 1955; Kleinfeld, Messite, and Tabershawe, 1955; Schepers and Durkan, 1955a; Hunt, 1956;Nagelschmidt, 1960; DeVilliers, 1961; Coscia et al., 1963; Gaido, Capellaro, and Delmastro, 1963; Scansetti, Rasetti, and Ghemi, 1963; Dettori, Scansetti, and Gribaudo, 1964; Kleinfeld et al., 1964a Kleinfeld et al., , b, 1965 Kleinfeld et al., , 1967 Kleinfeld et al., , 1973 Graham and Gaensler, 1965; Weiss and Boettner, 1967; Fristedt, Mattsson, and Schutz, 1968; ElGhawabi, El-Samra, and Mehasseb, 1970; Kleinfeld, 1970; Selikoff, 1973; Wegman et al., 1974). In people not employed in the talc industry, only isolated cases of pulmonary changes have been reported where there was either accidental exposure or excessive usage of talc (Jacobziner and Raybin, 1963; Jenkins, 1963; Gouvea et al., 1966; Zientara and Moore, 1970; Atlee, 1972; Nam and Gracey, 1972). ...
Data are presented on the effects on health of talc dusts from exposure in industry and use of talc-containing health products. The mineralogy of talc and the composition of cosmetic and industrial grade talc dusts are described. Studies in animals are reviewed, and epidemiological data are considered in relation to exposures that occur during industrial and consumer uses of talc dusts. Hamsters exposed to 8 mg/m3 of respirable cosmetic grade talc dust for up to 150 minutes a day for 300 consecutive days showed no difference in incidence or nature of pathological lesions from those observed in a group of untreated animals. A retrospective study of the causes of death of 227 talc mine millers exposed to cosmetic grade talc at the threshold limit value for talc (20 million parts per cubic foot) for an average of 15-8 years showed that the causes of death were no different from those in a control cohort not exposed to talc dust. The available data indicate that talc dust exposure in the modern mining of cosmetic grade talc does not appear to be injurious to health. The significantly lower dust exposure in the normal use of cosmetic grade talc dusts in talc-containing health and cosmetic products confirms that their use is not a hazard to health.
Clinical manifestations of interstitial lung diseases of occupational origin cover a wide spectrum. They change their epidemiology in response to occupational safety and health measures and new types of exposure requiring new diagnostic approaches. The incidence of well-known disorders like asbestosis is decreasing in countries which prohibited work with it, whereas in other regions the use of asbestosis ongoing with increase of associated diseases. On the other hand, newly identified exposure fields for beryllium lead to an increase of chronic beryllium disease which needs to be separated from chronic sarcoidosis, its perfect phenocopy. New techniques and new products cause new disorders like indium–tin oxide-lung and flock worker’s lung disease which are hard to diagnose since pathognomonic features are missing. For timely diagnoses an intense cooperation of pulmonary and occupational specialists is of high importance. New hazardous techniques and materials like nanoparticles are introduced and widely used even with exposures of consumers without an in-depth knowledge of their toxicological features. These new developments request surveillance measures which still are in their infancy.KeywordsChronic beryllium diseaseIndium–tin oxide-lungHard metal lungAsbestosisFlock worker’s lung diseaseNanoparticle induced-interstitial lung diseaseSiderofibrosisFlavoring-induced lung disease
Pneumokoniose ist eine Berufskrankheit, die bei Arbeitern auftritt, die organischen und anorganischen Stäuben in der Umwelt ausgesetzt sind, wie im Bergbau, beim Sandstrahlen und Töpfern, bei Steinmetzarbeiten und in der Landwirtschaft. Die entzündliche Reaktion der Lunge auf lungengängigen Staub verursacht die Bildung von Makulae, Knötchen und Fibrose, und ein höherer Kieselsäuregehalt im eingeatmeten Staub ist mit einer erhöhten Fibrosierung verbunden. Die Mischstaubpneumokoniose (MDP) entsteht durch die Exposition gegenüber Staub, der 10–20% Kieselsäure enthält, und in der Lungenbildgebung zeigen sich unregelmäßige Trübungen. Die Histopathologie spielt bei der Diagnose der MDP eine entscheidende Rolle. Günstige Behandlungsergebnisse sind möglich, doch die MDP entwickelt sich langsam über viele Jahre konstanter Exposition und ist durch eine Verschlechterung von Dyspnoe und Husten gekennzeichnet, die allmählich zum Cor pulmonale fortschreiten. Die einzig wirksame Behandlung besteht darin, die Exposition zu beenden, weshalb es für ein günstiges Outcome unerlässlich ist, die Krankheit frühzeitig zu erkennen. Wir stellen einen Fall von Mischstaubpneumokoniose bei einem Bauern aus Südamerika vor, der an Asthma litt. Er stellte sich mit sich verschlimmernder Dyspnoe und multiplen Knötchen in beiden Lungen in der Bildgebung und einem Cor pulmonale vor. Es wurde eine umfassende diagnostische Abklärung durchgeführt, die Malignität und Tuberkulose ausschloss. Die Analyse von Biopsieproben aus der videoassistierten thorakoskopischen Chirurgie (VATS) bestätigte die Diagnose einer Staubpneumokoniose. Er hatte einen Zusammenfluss von unregelmäßigen Knoten in den oberen Lungenlappen, und der größte war 2,1 cm groß. Dies passt zur Definition der progressiven massiven Fibrose der Internationalen Arbeitsorganisation (ILO). Dies, zusammen mit seinem Cor pulmonale, ergibt eine schlechte Prognose, selbst nachdem er von der Staubexposition befreit wurde. Er erhielt Steroide, was zu einer symptomatischen Besserung führte, und er wurde zur weiteren Nachsorge beim Pneumologen entlassen.
La neumoconiosis es una enfermedad profesional que afecta a trabajadores con exposición ambiental a polvo orgánico e inorgánico, como en la minería, el granallado, la alfarería, la cantería y la agricultura. La respuesta inflamatoria del pulmón al polvo respirable provoca la formación de máculas, nódulos y fibrosis, y un contenido mayor de sílice en el polvo inhalado se asocia con un aumento en la fibrosis. La neumoconiosis mixta por polvo (MDP) se caracteriza por la exposición a polvos que contienen 10–20% de sílice, con imágenes pulmonares que muestran opacidades irregulares. La histopatología desempeña un papel vital en el diagnóstico de la MDP. Aunque tiene un pronóstico favorable, la enfermedad evoluciona lentamente, a lo largo de muchos años de exposición constante, y se caracteriza por un agravamiento de la disnea y la tos, que progresa gradualmente hasta convertirse en cor pulmonale. El único tratamiento eficaz es eliminar la fuente de exposición, por lo que es esencial reconocer la enfermedad de forma temprana para lograr un resultado favorable. Presentamos un caso de neumoconiosis mixta por polvo en un agricultor de Sudamérica que padecía asma. El paciente se presentó con agravamiento de la disnea y múltiples nódulos en ambos pulmones en el diagnóstico por imagen, y cor pulmonale. Tras un amplio estudio, se descartó cualquier neoplasia maligna y tuberculosis. El análisis de las muestras de biopsia de cirugía toracoscópica asistida por video (VATS) confirmó el diagnóstico de neumoconiosis mixta por polvo. El paciente presentaba una confluencia de nódulos irregulares en los lóbulos superiores de los pulmones, y el mayor medía 2.1 cm. Esto coincide con la definición de la Organización Internacional del Trabajo (OIT) de fibrosis masiva progresiva. Este hallazgo, junto con el cor pulmonale, indica un mal pronóstico, incluso luego de eliminar la exposición al polvo. Se administraron corticoides, que produjeron una mejoría sintomática, y se dio de alta al paciente para seguimiento con el neumólogo.
Introduction
Silicosis is a chronic progressive disease caused by inhalation of crystalline silica. Most cases develop in underground mine workers and in subjects involved in the extraction of natural stone (slate and granite). In view of the progressive emergence of new cases of silicosis in artificial quartz conglomerate workers, we performed a study to analyze the characteristics of silicosis produced by this new agent in Spain.
Methods
The study consisted of a series of 96 cases of silicosis diagnosed according to international criteria during the period 2010–2017. We analyzed clinical, radiological, pathological and functional characteristics.
Results
Mean age of participants was 45 years; 55% had simple silicosis and 45% had complicated silicosis. Ten patients were diagnosed with accelerated silicosis, with a mean age of 33 years. Mean time of exposure to conglomerates was 15 years, and 77% had not used appropriate protection measures. Half of the patients were asymptomatic and presented different classic forms on chest X-ray and chest high-resolution computed tomography, along with ground-glass images. No lung function changes were recorded.
Conclusions
Silicosis in artificial quartz conglomerate workers occurs in a young, actively employed population, a considerable percentage of whom present an accelerated form. They have few symptoms and no functional limitations. Protection measures are scarce. It is important to characterize these features to provide early diagnosis and implement the necessary preventive measures.
Schon im 16. Jahrhundert hat Theophrastus Bombastus von Hohenheim, genannt Paracelsus, in einer Reisebeschreibung auf die „Bergsucht oder Bergkrankheiten“ hingewiesen, and bereits 1679 hat Diemerbroeck auf die Ansammlung von Steinstaub in Steinhauerlungen aufmerksam gemacht. Aber noch im 19. Jahrhundert haben Virchow and Henle die Behauptung Pearsons, daß das „Lungenschwarz“ inhalierter and im Lungengewebe eingelagerter Staub sei, bezweifelt, bis Kussmaul and Schmidt den Beweis erbringen konnten, daß in Lungen and Lymphknoten von erwachsenen Personen unterschiedliche SiO2-Mengen vorhanden sind. Der Begriff Pneumokoniosis, der heute noch im internationalen Schrifttum die Staublungenerkrankungen zusammenfaßt, wurde von Zenker geprägt and der Begriff Silikose von Visconti.
Dort, wo ein Arbeiter bei seiner beruflichen Tätigkeit einem Staub ausgesetzt ist, der Quarz (kristalline Kieselsäure) oder seine Modifikationen in lungengängiger Korngröße (< 5 µm) enthält, besteht die Gefahr, daß er an einer Pneumokoniose erkrankt mit einer für den Quarz spezifischen Gewebsveränderung. Scit der Johannesburger Konferenz im Jahre 1930 wird der Quarz als Ursache der spezifischen Silikosefibrose betrachtet. Der ursächliche Zusammenhang zwischen silikotischen Gewebsveränderungen und Quarz ist seither vielfach belegt worden, so daß an der Formulierung „ohne Quarz keine Silikose“ mit gewissen Einschränkungen auch heute noch festzuhalten ist. Jede feste freie Quarzmodifikation kann silikogen wirken. Es gibt jedoch Modifikationen, so Tridymit und Cristobalit (King, Mohanty
et al., 1953a), die stärker wirksam sind als der in der Natur am häufigsten vorkommende Quarz. Die amorphen Modifikationen, z.B. Quarzglas, sind in ihrer Wirkung dagegen weitaus schwächer (King, Mohanty
et al., 1953b; Stöber, 1967). Von Stöber wurden 1964 aus dem CoconinoSandstein des Arizonakraters zwei Hochdruckmodifikationen des Quarzes, das Coesit und das Stichowit, isoliert, von denen letzteres sich als inert erwies (Strecker, 1965a). Gewerbehygienisch spielen neben dem Quarz an sich nur das Cristobalit und Tridymit eine Rolle Einbrodt, 1965; Katsnelson, Babushkina
et al., 1967).
This paper will only consider the risk of non malignant pulmonary disease (“Silicatosis”) associated with the inhalation of phyllosilicate dust at the workplace. Other sources of exposure were dealt with by Drs BOUTIN and VIALLAT at this conference and evaluation for carcinogenicity is the role of the International Agency for Research on Cancer (IARC). Among the non fibrous phyllosilicates, only talc has been evaluated for carcinogenicity (World Health Organization 1978). According to IARC, there is inadequate evidence for the carcinogenicity to humans of talc not containing asbestiform fibres, while there is sufficient evidence for the carcinogenicity to humans of talc containing asbestiform fibres.
Pneumoconiosis offers fundamental understandings on the relationship between environment and human diseases. Toxicity of an inhaled dust is not only determined from both qualitative (chemical composition, physico-chemical properties etc.) and quantitative aspects of the dust, but also influenced greatly by patterns of dust exposure in that the same kind of dust does produce entirely different pathologies, e.g., acute silicosis and classical silicosis following inhalation of crystalline silica-rich dust. Specific pathogenicity of a dust is established, when a definite dose-response relationship exists between the dust and certain pathology. Crystalline silica and silicotic nodules with or without massive fibrosis (silicosis) represent the single specific combination of dust and pathology. Pathology of silicosis, however, entails a broad spectrum of lesions, which include non-specific but fairly common findings such as diffuse interstitial fibrosis. There is not dose-response between silicosis and lung cancer in terms of severity of disease. It is possible, however, to assume a confounding effect of fibrosis of silicotic type, which destroys epithelial cells in contrast to fibrosis of asbestosis type (diffuse interstitial fibrosis), where epithelial cells proliferate.
The aim of this review is to describe radiologic manifestation of silicosis. Predominant abnormality is multiple nodules in both upper lung zones, which often coalesce to form a large opacity over time. The nodular opacities are characteristically well defined in spite of their small size. Emphysema is often severe, especially when large opacity develops. Tuberculosis, lung cancer and collagen vascular diseases are well known complication.
Though, the incidence of silicotic patients has been decreased due to dust control in working places, mixed dust pneomoconiosis(MDP) caused by inhalation of silicate compound dust has noted in radiological (CXR and CT) and pathological characteristic findings. The item is focuced in MDP ans diffuse interstitial pulmonary fibrosis, and correlative studies between radiological and pathological findings of silicosis, MDP and asbestosis were performed.
OBJECTIVES
To evaluate the association between silica, silicosis and lung cancer, the mortality of 724 patients with silicosis, first diagnosed by standard chest x ray film between 1964 and 1970, has been analysed by a cohort study extended to 31 December 1997.
METHODS
Smoking and detailed occupational histories were available for each member of the cohort as well as the estimated lifetime exposure to respirable silica dust and radon daughters. Two independent readers blindly classified standard radiographs according to the 12 point International Labour Organisation (ILO) scale. Lung function tests meeting the American Thoracic Society's criteria were available for 665 patients. Standardised mortality ratios (SMRs) for selected causes of death were based on the age specific Sardinian regional death rates.
RESULTS
The mortality for all causes was significantly higher than expected (SMR 1.35, 95% confidence interval (95% CI) 1.24 to 1.46) mainly due to tuberculosis (SMR 22.0) and to non-malignant chronic respiratory diseases (NMCRD) (SMR 6.03). All cancer deaths were within the expected numbers (SMR 0.93; 95% CI 0.76 to 1.14). The SMR for lung cancer was 1.37 (95% CI 0.98 to 1.91, 34 observed), increasing to 1.65 (95% CI 0.98 to 2.77) allowing for 20 years of latency since the first diagnosis of silicosis. Although mortality from NMCRD was strongly associated to the severity of radiological silicosis and to the extent of the cumulative exposure to silica, SMR for lung cancer was weakly related to the ILO categories and to the cumulative exposure to silica dust only after 20 years of lag interval. A significant excess of deaths from lung cancer (SMR 2.35) was found among silicotic patients previously employed in underground metal mines characterised by a relatively high airborne concentration of radon daughters and among ever smokers who showed an airflow obstruction at the time of the first diagnosis of silicosis (SMR 3.29). Mortality for lung cancer related to exposure was evaluated with both the Cox's proportional hazards modelling within the entire cohort and a nested case-control study (34 cases of lung cancer and 136 matched controls). Both multivariate analyses did not show any significant association with cumulative exposure to silica or severity of silicosis, but confirmed the association between mortality for lung cancer and relatively high exposure to radon, smoking, and airflow obstruction as significant covariates.
CONCLUSIONS
The findings indicate that the slightly increased mortality for lung cancer in this cohort of silicotic patients was significantly associated with other risk factors—such as cigarette smoking, airflow obstruction, and estimated exposure to radon daughters in underground mines—rather than to the severity of radiological silicosis or to the cumulative exposure to crystalline silica dust itself.
The physiological and pathological changes associated with occupational exposure to mineral dusts (pneumoconioses) are briefly outlined. The minerals can be in the form of fumes, particulates, or fibres. Excessive exposure to mineral dusts results in scarring of the lung tissue and disturbance of the exchange of gases, leading to respiratory failure; in addition, this makes the lungs more sensitive to infections. The different patterns of scarring as a result of exposure to quartz, coal dust, or asbestos are described. Exposure to asbestos dust is associated with an excess of carcinoma of the lung and tumours of the pleura. There is epidemiological evidence from South Africa and Britain establishing that the pleural tumours (mesotheliomas) occur mainly in those exposed to crocidolite asbestos. -Author
Neutron activation analysis, using inelastic scattering, provides a quantitative, non-invasive technique of studying silica burdens and is potentially useful as a screening procedure for occupationally exposed workers. In this method, silicon is measured using the fast neutron inelastic scattering reaction28Si(n,n )28Si which emits 1779 keV -rays. The method requires a source of fast neutrons (> 2MeV). A 2MV Van de Graaff generator has been developed to produce a pulsed beam of 5.2 MeV neutrons. The pulsed beam has the advantage of improving measurement sensitivity by separating in Bone the inelastic scattering -rays from those due to thermal-neutron capture reactions. The incident neutron energy was chosen to maximise the silicon -ray count rate, while keeping the signal from the competing reaction31P(n,)28Al negligible.
Despite continuing efforts at environmental control, occupational lung disease continues to be a major health problem. Asbestiform and siliceous dusts commonly are implicated as causative factors in fibrotic and carcinogenic pulmonary diseases. The basic pathogenetic mechanisms leading to these conditions are poorly understood and have been approached in a limited fashion. With the increasing availability of electron and X‐ray microanalytical techniques, investigators have been able to determine important associations between inhaled particles and specific anatomic and cellular lesions. In attempts to phagocytize, package, digest, and export particles, pulmonary cells and other functional units put out a variety of proteolytic, elastolytic, and inflammatory products. The alveolar macrophage, as the first line of cellular defense in the lower respiratory tract, plays a major role in mediating the biologic activities of many inhaled particulates. This chapter details electron optical techniques currently used to study the distribution, fate, and biologic activity of inhaled particulates and describes the information available on the mechanisms of particle‐induced lung disease.
Over the last half century, there has been a sustained decline in the prevalence of silicosis in developed countries. This success has primarily been the result of an emphasis on engineering controls, with the capture of generated silica dust. This has allowed for adherence to exposure limits and the protection of the respiratory health of the worker. Yet sporadic cases continue to occur in developed countries and epidemics are still recognized in underdeveloped countries.
In this review, we address data describing the pathogenesis of silicosis. Although untried, much of this research suggests that pathways associated with the development and progression of silicosis may be altered by currently available interventions.
Following Na-hypochlorite digestion of lung tissue, mineral particles extracted in the chloroform layer were deposited directly on a pre-smoothed carbon planchet for combined scanning electron microscopy and X-ray energy dispersive spectrometry (SEM and XEDS). Total mineral particle counts were obtained, and detailed physical characteristics of the fibrous particles were documented at 600, 1,500, 4,500 and 9,000 x in three lungs without, and one lung with, histories of occupational exposure. This preparation method was simple, collected more than 99% of identifiable mineral particles in the chloroform layer, gave excellent object to background contrast without heavy metal coatings, and was suitable for XEDS. Comparable fibrous particles from the chloroform layer could also be studied by selected-area electron diffraction to complement the results of XEDS. By this method, we found particles or fibers larger than 0.1 μm were readily counted and measured at 4,500 x. At 600 x, ferruginous bodies were found to be more than twice in number than when sought for by light microscopy. It was determined that 4,500 x is the most efficient magnification to examine and diagnose this type of specimen. The present study illustrates the importance of determining the most efficient magnification to be utilized in particle counts.
Sera from 2421 coalminers, representing all the radiological categories of pneumoconiosis, and from 260 healthy blood donors, as controls, were examined for antinuclear factor and rheumatoid factor. Antinuclear factors were present in 21.5% of sera from the controls and in 23.1% from the coalminers' group. Rheumatoid factor was present in 5.3% of coalminers and as expected occurred particularly in the few men with progressive massive fibrosis who also had rheumatoid disease. The combined prevalence of both factors showed an increase with age at all disease levels and a significant association with pneumoconiosis category only in men older than 60 years. This study provides no evidence that autoantibodies are likely to be of value in detecting men predisposed to the development of massive fibrosis other than those with rheumatoid disease.
There has been increased public awareness of the potential danger from exposure to hazardous dust in various occupations. This study aims to validate the qualitative analysis of scanning electron microscopy (SEM) of lung samples by 1) correlation of induced sputum (IS) findings to clinical findings, 2) comparing hazardous particles in IS to those in biopsied lung specimens, and 3) assessing whether the particles present in the lungs of transplanted patients correlate with occupational history of dust exposure. Forty patients with occupational history were included; of whom 35 filled in questionnaires. Twenty-four of them had SEM analysis of their IS, and 11 of these 24 also had SEM analysis of their lung tissue. Another 11 lung biopsies from patients with occupational history were scanned by SEM and compared with 10 lung biopsies from patients with no occupational history. SEM analysis of IS was as efficient for detecting hazardous particles as was SEM analysis of lung tissue; silica was detected better in sputum. Exposure to silica was the main chemical element associated with a high likelihood to show abnormalities in IS (Odds ratio 19.41 CI = 0.270-1398.33). The average number of detected hazardous chemical elements in patients with an occupational history of exposure was 4 +/- 1.61 in IS and 3.55 +/- 2.02 in lung tissue (P = 0.57); it was 1.5 +/- 0.85 from transplanted occupationally exposed patients compared with 0.36 +/- 0.67 in transplanted non-exposed patients (P = 0.003). SEM analysis of particles in IS and lung tissue can elucidate the causative agent(s) of otherwise idiopathic interstitial lung disease among occupationally exposed workers.
Some species of minerals, when comminuted and aerosolized in the form of respirable-size particulate dusts, are recognized as capable of producing disease in man after their inhalation. Comprehensive listings of such agents are in the current literature (e.g. in Aponte, 1970; Langer & Mackler, 1972; Ehrenreich et al. 1973 a , b ) and many of these and their effects are well known and receive much attention. Asbestos fibres of all varieties, ampbibole and quartz contaminated talcum powders (see Rohl et al. 1976), fibrous amphiboles and their cleavage fragments which contaminate the ambient environment (e.g., the contamination of Lake Superior with cummingtonite-grunerite, as discussed in Bowes, Langer & Rohl, 1977), have been the subject of recent intensive investigations mostly due to their protential impact to large segments of the general population.
The prevalence of respiratory symptoms and chest radiographic and spirometric abnormalities was assessed among 397 employees of an activated carbon plant. Definite radiographic findings of pneumoconiosis, consisting of p-type, rounded opacities in the lower lung fields without firbosis or coalescence, were present in 9.6% of men and were related to cumulative dust exposure. Lesser degrees of radiographic abnormality suggesting pneumoconiosis were present in 11% of men and 2% of women. Spirometric values were substantially lower in blacks than in whites. However, cumulative dust exposure was not an important determinant of pulmonary function in either race. Review of lung biopsy speciments that had been obtained previously in two employees revealed extensive carbon depositiion but minimal associated fibrosis. Prolonged inhalation of activated carbon dust leads to pulmonary deposition of carbon and raciographic signs of pneumoconiosis; such deposition has little, if any, effect on respiratory symptoms or pulmonary function.
The mineral dust diseases, also called the pneumoconioses, comprise a wide spectrum of conditions ranging from diseases characterized by diffuse collagenous pulmonary reactions to relatively small lung burdens of bioactive dusts (e.g. silicosis, asbestosis) to diseases characterized by largely non-collagenous reactions in the face of heavy lung dust burdens (e.g. coal workers pneumoconiosis). According to information submitted to the International Labour Office, which is however incomplete, substantial numbers of individuals are still at risk for the mineral dust diseases in the workplaces of the world. An overview of their epidemiology in industrialized and industrializing countries reveals more commonalities than contrasts. Commonalities include the major determinants of disease (including exposure level, intensity and particle size distribution), their clinical manifestations and, probably, secular trends towards less clinically severe disease, at least in the larger, better controlled workplaces. Still a risk however, in both industrializing as well as industrialized countries, are the small, uncontrolled workplaces, often the source of mini-epidemics. Contrasts relate to the incidence and/or prevalence rates of tuberculosis amongst workforces at risk for the mineral dust diseases. Rates, which are invariably higher in industrializing than in industrialized economies, usually reflect the background tuberculosis rates in the populations which furnish the industrial workforces and they should be the target for control measures. Research in the industrialized countries should focus on disease mechanisms and on the bioactivity of workplace contaminants, old and new, and in the industrializing countries on the distribution and determinants of mineral dust diseases in their workplaces.(ABSTRACT TRUNCATED AT 250 WORDS)
Auf Grund physikalischer berlegungen wurde fr ein der menschlichen Lunge mglichst weitgehend angepates Lungenschema zahlenmig ausgerechnet, in welcher Menge sich in der eingeatmeten Luft suspendierte Teilchen verschiedenster Gre (Schwebstoffe) an den einzelnen Stellen des Bronchialbaumes absetzen. Die Ergebnisse zeigen, da grbere Teilchen (Radius grer als 10 @#@) bereits in der Trachea und in den greren Bronchien an die Schleimhute gelangen, kleinere (Radius etwa 1 @#@) hingegen zur Hauptsache im respiratorischen Teil der Lunge ausgefiltert werden; noch kleinere Teilchen (Radius zwischen 0,1 und 0,3) werden grtenteils wieder ausgeatmet, von den kleinsten in Betracht kommenden Teilchen setzt sich jedoch wieder eine grere Menge ab. Die Rechnungsergebnisse drfen auf Grund experimenteller Nachprfung als gesichert gelten. Sie knnen deshalb bei medizinischen Verfahren benutzt werden, wenn es sich um die Frage der Wahl einer gnstigsten Gre der Schwebeteilchen fr die Inhalationsbehandlung eines bestimmten Teiles des Bronchialbaumes handelt.
Ein 47 1/2 Jahre alter, früher gesund gewesener Mann arbeitete 25 Jahre lang in einer Portlandzementfabrik. Er war mindestens 17 Jahre lang einer starken Bestäubung teils durch Roh-, teils durch Fertigzement ausgesetzt gewesen. 12 Jahre vor seinem Tode traten röntgenologisch nachweisbare, dicht stehende Herdschatten in der Basis beider Lungenober- und den angrenzenden Abschnitten der Unterlappen auf. DieObduktion zeigte eineschwere Staublungenerkrankung mit Ausbildung von symmetrischen, schmetterlingsförmig angeordneten, sehr großen geballten Schwielen. Histologisch ließ das Narbengewebe eine eigenartig lockere Textur erkennen.
Auf Grund der pathologisch-anatomischen, der Untersuchung der nachKoppenhöfer behandelten veraschten Lungenschnittpräparate, sowie der staubanalytischen Untersuchungen durch das Silicoseforschungs-institut in Bochum (Dr.Landwehr) trägt der Fall unserer Staublunge durch Portlandzement die Züge sowohl einer Mischstaubsilicose als auch einer Silicatose.
Da es sich um die erste pathologisch-anatomische Beobachtung einer Zementstaublunge handelt, wurden die mutmaßlichen Entstehungsbedingungen genauer erörtert. Danach ist eswahrscheinlich, daß dispositionelle in der Konstitution des Verstorbenen begründete Voraussetzungen für die Ausbildung der besonders schweren Pneumonokoniose mitverantwortlich gewesen sein müssen.
A clinical evaluation of a new cephalosporin, cephazolin, in obstetric patients is presented. Sixteen cardiac patients received the drug prophylactically as antibiotic cover during labour. Eighteen patients with miscellaneous antenatal and puerperal infections received the drug as primary treatment. The data obtained indicate adequate serum and tissue levels with the dose used, and corresponding clinical response. The impression is of a safe and efficaceous drug in the described obstetric situations requiring antibiotic therapy. It may be given prophylactically and with confidence to the cardiac patient in labour.
Three volunteers were exposed via mouth inhalation to triphenyl phosphate (non-hygroscopic). Particle sizes tested ranged from 0.14 to 3.2 ..mu..m (6 homogenous steps). Deposition curves show minimum retention of 0.4 ..mu..m particle size. Brownian motion (random impact with gas) varies by d/sup -//sup 1/2; settling effect and impact effect vary by d/sup 2/ so minimum deposition is where these three processes counteract each other. Slower, deeper breathing resulted in greater deposition; differences were greater with larger particles, because settling and impaction vary with first power of time and Brownian varies with square root of time. Pneumoconiosis-producing dusts act on deep pulmonary tissues whereas major cancer producers act on the bronchi.
In the absence of adequate preventive measures the manufacture of carbon electrodes is attended by a considerable dust hazard. The present paper is based on a study of the clinical, radiological, and pathological changes resulting from inhalation of this dust, which is derived from crushed coke and anthracite.An account is given of the findings in a clinical survey of 15 men who had been employed for at least 10 years in manufacturing carbon electrodes. Four of these men were suffering from complicated and five from simple pneumoconiosis.In addition, the findings in three necropsied cases (two complicated and one simple) are recorded in detail. Bacteriological examination of the lungs and analysis of the lung dust was carried out in the two cases of complicated pneumoconiosis.It is shown that carbon electrode makers may develop simple pneumoconiosis with focal emphysema and that this may complicated by the development of massive fibrotic lesions. Both the simple and the complicated pneumoconiosis are indistinguishable from the corresponding conditions in other coalworkers.Quartz was almost entirely absent from the lung dust of the two necropsied cases with massive fibrosis and in one of these cases virulent tubercle bacilli were shown. The significance of these findings is discussed in relation to the aetiology of progressive massive fibrosis. While it is evident that they are incompatible with the “silica” theory they provide some limited support for the “tuberculosis” theory.
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