SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
An enameler with dysphagia was found to have extrinsic compression of the esophagus by enlarged mediastinal lymph nodes. Scalene lymph node biopsy revealed silicosis, and tissue cultures grew Mycobacterium intracellulare. We believe our patient is the first reported to have dysphagia due to silicotic adenopathy complicated by an atypical mycobacteriosis.
In order to evaluate low serum alpha-1-antitrypsin level as a contributory factor of combined emphysema in silicotic patients, serum alpha-1-antitrypsin analysis was carried out in 80 patients with silicosis. Low serum alpha-1-antitrypsin level was found in 5 patients. Large opacities were observed roentgenologically in only 1 out of these 5 cases in contrast to 31 of the other 75 cases. Also the suggestive findings for the emphysema were showed in 4 of these 5 cases while such findings were found on their chest X-ray films in only 43 of the other 75 cases. FEV 1.0% below 50 were calculated in 3 of the 5 cases, on the contrary in 22 of the 75 cases. RV above 50% predicted value was showed by all the 5 low antitrypsin patients, in contrast to only 25 of other 74 cases. The silicotic patients with low serum alpha-1-antitrypsin concentration are most likely to have an association with a high incidence of complicated emphysema.
A patient with hereditary spherocytosis and silicosis who developed an IgA(lambda) monoclonal gammopathy is reported. It was thought that a combination of hereditary factors, a chronic hemolytic stimulus to the reticuloendothelial system and an adjuvant effect provided by presence of diffuse silica might have contributed to the development of monoclonal gammopathy.
Previous experiments with the sheep model of silicosis have demonstrated a reduction of the pathological activity of quartz after treatments with aluminum lactate (Al-lac), such as Al-lac pretreatment of intratracheally injected quartz or Al-lac inhalation of quartz-exposed animals. Preliminary data also suggested a more effective alveolar clearance of quartz treated with Al-lac. The present study was undertaken to fully document the effect of Al-lac treatments on the pulmonary retention of quartz. Sheep (on average, 27 per group) received a single injection in the tracheal lobe of either 100 mg/100 mL of alpha-quartz, 100 mg/100 mL of alpha-quartz followed by Al-lac inhalations at 1-month intervals, or 100 mg/100 mL of alpha-quartz Al-lac pretreated in vitro. Samples of lung parenchyma were analyzed at 2, 6, and 10 months after the injection. The quartz concentration in each sample was measured using the X-ray diffraction method. The concentrations were expressed in micrograms of quartz per milligram of dry lung parenchyma. The geometric mean concentrations in each of the three groups at 2 months were statistically different (ANOVA of the log values; p = .016) as well as at 6 months (ANOVA of the log values; p = .001). Al-lac clearly reduced the pulmonary retention of quartz. Both modalities of Al delivery were equally effective in clearing quartz up to 2 months, which may explain the documented reduction in pathological activities after in both forms of therapy. However, quartz soaked in Al-Lac solution was more effective than inhalation of Al-lac after quartz exposure. The half-life of both native quartz and quartz Al-lactate inhaled was 5.05 and 4.99 months, respectively, while it was 3.1 months for Al-treated quartz. Al-lac inhalations after the second month of exposure do not significantly affect the rate of clearance of deposited quartz.
Electron spin resonance (ESR) measurements show that grinding of quartz particles in air produces silicon-based (Si. and SiO.) radicals which decay with aging in air. ESR spin trapping measurements provide evidence for the generation of hydroxyl and possibly superoxide radicals from a suspension of fresh quartz particles. The hydroxyl radical generation potential of the fresh quartz particles decreases on storing in ambient air and on the addition of catalase, superoxide dismutase, desferroxamine, or DMSO. Silica-induced lipid peroxidation also decreases on storing the fresh particles in ambient air. These findings suggest that oxygenated radicals play a role in the biochemical mechanism of pneumoconiosis in general and acute silicosis in particular.
Silicosis, which acquired great significance during the period of increase in mining and construction, continues to be a pathology with a high morbidity and mortality within pneumoconiosis. Exposure to silica produces pathological, clinical and radiological alterations that together with compatible personal antecedents suggests its diagnosis in a simple way. The associated complications as well as its differential diagnosis from other types of pneumopathy mean that a review of this entity is needed.
A case is reported of rapidly progressive silicosis in a 30-year-old male who developed symptoms two years after first exposure and died 30 months later. The causative agent was silica powder. This case serves to highlight the fact that this potentially dangerous material is currently being used in industry and that adequate precautions are not always taken.
The authors verify whether in silicosis the accumulation of silicon dioxide (SiO2) particles in the lung can induce changes of the activated T lymphocytes in the peripheral blood. The lymphoblastic transformation of lymphocytes stimulated with phytohemagglutinin (PHA), concanavalin A (Con A), Mycobacterium tuberculosis (Mt) and purified protein derivative (PPD) was studied using the classical methods. It was observed that in patients exposed to SiO2 lymphocyte reactivity to the above stimulants decreases. Significant differences between patients and controls were observed only in the response to PHA (p < 0.001).
Three adult female North American river otters (Lutra canadensis) demonstrated severe anesthetic complications shortly after being immobilized for dental procedures. Two of the animals died shortly after anesthesia, and the third otter died 2 mo after immobilization. All three animals were diagnosed with pulmonary silicosis on the basis of histopathology, polarized light microscopy, and mass spectrometry. One animal also had primary pulmonary bronchoalveolar carcinoma. Significant concurrent disease was not found in other organs. Analysis of the lung tissue by laser microbe mass spectrometry confirmed the presence of an aluminum silicate in the lung tissue associated with insulation material used in nest box construction.
An accelerated silicosis case made our Occupational Health Unit focus on a pathology thought dropping so far to die out. Furthermore this event occurred in a manufacturing (lost-wax process in jewelry casting) regarded as a low-risk exposure. Besides unsuitable procedures, the user had underestimated the specific risk of that raw material (talcum-like powder at 60-80% silica crystalline level), commonly called "gypsum", inappropriately labelled since not yet adequately classified by the hazardous substances list. The widespreading of this manufacture in our area (Vicenza district) and the recent inclusion of Silica Crystalline in the Class 1 made by IARC (Jan 1997) have urged this Unit to take action in industrial hygiene investigations, instructions to the workers, mandatory directions to dealers concerning the proper hazard labelling for products containing silica crystalline and circulation of information among other Occupational Health Units involved.
The clinical observation, the work history, the analysis of pulmonary function tests and, mainly, the conventional x-ray chest radiograms have represented, til now, the diagnostic basis for pneumoconiosis (silicosis, mixed dust pneumoconiosis, asbestosis). Recently, the high resolution chest tomography (HRCT) has been introduced into the diagnostic procedures: such method seems to have its main application in the assessment of incipient clinical pictures of pneumoconiosis, particularly when characterized by normal pulmonary function tests. 75 silica- and mixed dust exposed workers were submitted to both radiologic methods. The great majority of them had already been recognized to be affected by asbestosis. The statistical analysis (Cohen K) showed a satisfactory agreement between radiographic and tomographic I.L.O. classes. However, high resolution tomography appeared to be more accurate in the assessment of less severe clinical pictures. In conclusion, we underline the importance of high resolution chest tomography in the evaluation of individual clinical cases, particularly when forensic problems are involved.
In November 1997, a 61-year-old man was admitted to our hospital complaining of dyspnea. He had worked as a miner for 10 years and had received medical treatment based on a diagnosis of idiopathic interstitial pneumonia at our hospital since 1984. In conjunction with the progression of interstitial pneumonia, the patient's serum CA 19-9 had gradually increased since 1992, reaching 9,920 U/ml in 1997. Though cancer of the pancreas or other organs was suspected, an extensive examination revealed no malignancy. In April 1998, the patient died of bacterial pneumonia. Lung autopsy specimens disclosed severe interstitial fibrosis with prominent silicotic nodules. Based on these findings, silicosis was diagnosed. In immunohistochemical staining for CA 19-9, the lumina of severely fibrotic lesions covered with epithelial cells stained positively with anti-CA 19-9 antibody. These findings suggested that serum CA 19-9 may have been produced in the epithelial cells. We speculated that increased serum CA 19-9 levels in patients with interstitial pneumonia may occasionally be more indicative of the magnitude of destruction of lung architecture than the degree of disease activity.
We present a case of progressive multifocal leukoencephalopathy (PML) diagnosed at autopsy, in which JC virus infection of the central nervous system was confirmed by means of electron microscopy and immunohistochemistry. The patient had been receiving steroid hormones due to suspected sarcoidosis or pneumoconiosis. Diffuse silicosis in lungs and in hilar and mediastinal lymph nodes was diagnosed at autopsy. Intranuclear inclusions, ultrastructurally typical of JC virus were found in some oligodendrocytes in the white matter. However the strongest immunopositive viral deposits were found in the cerebellar cortex, also within Purkinje cells. Numerous apparently apoptotic cells seen in white matter suggest that this mechanism of cell elimination plays an important role in PML pathogenesis and hence anti-apoptotic treatment may alleviate the symptoms and prolong survival.
BACKGROUND: In 1997 a Working Group of the International Agency for Research on Cancer changed an earlier classification of crystalline silica as a human carcinogen from Group 2A to Group 1, though commenting that the carcinogenicity might vary with industrial circumstances and depend on additional factors affecting biological activity, including the distribution of its polymorphs. OBJECTIVE: We aimed to determine whether pure quartz exposure uncomplicated by the presence of other contaminating carcinogens, as experienced by workers in the production of high-grade industrial sand, was causally related to an increased risk of lung cancer. METHODS: A cohort of 2670 men employed before 1980 for 3 years or more in one of nine North American sand-producing plants and a large associated office complex was selected for study. Of the cohort, 2644 (99%) were traced through 1994, and certificated cause of death ascertained for 1025 (99%) of the 1039 men known to have died. Standardised mortality ratios (SMRs) were calculated for the main causes of death, using both US and state or provincial male mortality rates for reference. FINDINGS: The main analyses of deaths, 20 or more years after first employment against regional rates, gave the following SMRs: all causes 109, lung cancer 139, other malignancies 98, non-malignant respiratory disease 161, and nephritis/nephrosis 244. There were, in total, 37 deaths from silicosis or silico-tuberculosis, with one or more death at least in all nine production plants. Analyses failed to show any relation between lung cancer risk and duration of employment. The increased SMR for lung cancer was wholly due to high rates in four plants in two states, whereas no increase was found in the remainder of the cohort. CONCLUSION: In the absence of information on smoking histories and risk in relation to estimated exposure, the increased SMR for lung cancer (139), although statistically significant, cannot be attributed confidently to crystalline silica. An answer to the question of attributability must await the findings of the nested case-control study, in which level of exposure and smoking habits were ascertained for cases and matched controls. The strong indication in this cohort of excess mortality from non-malignant renal disease deserves further investigation.
The amino acid composition of lung, serum and liver in silicotic rats was studied in order to assess the availability of precursors in lung for fibrogenesis. It was observed that the pool of ornithine, arginine, alanine, leucine, valine, glutamic acid, lysine, proline and glycine underwent marked alterations. Free arginine, proline and leucine were only detectable in silicotic lung, while free glycine, glutamic acid and glutamine pools decreased significantly in liver. Changes in amino acid metabolism as a result of silicosis are discussed.
To study changes in liquid crystal structure of blood serum, the authors used intratracheal model of experimental silicosis in rats exposed to DQ12 quartz dust. Early stages of disease demonstrated changes in blood serum structurization, seen in polarized light. Morphology of those changes could serve as a characteristic of silicotic process intensity.
Evaluation of diagnostic possibilities of high definition computerized tomography was performed on the material of 38 patients with recognized silicosis of small opacities on the bases of long lasting exposition, clinical and radiographic picture. Special usefulness of HRCT was shown in revealing early, scanty, radiographically imperceptible nodular changes. The presence of the so-called air traps was shown on expiratory sections.
In March 1985, two cases of silicosis in former employees of a sanitary-ware pottery (i.e., a manufacturer of china plumbing fixtures) were identified from death certificates by the New Jersey State Department of Health (NJSDH). A site visit to the pottery in January 1987 revealed potential overexposure of employees to crystalline silica throughout the plant. This report summarizes the investigation of employee exposure to silica.