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A case of silicosis associated with Crohn's disease. Diagnostic and pathogenetic considerations.

A case of silicosis associated with Crohn's disease is reported. Symptoms, radiological and endoscopical findings suggested Crohn's disease in a man, who had worked as ceramist and in whom silicosis was diagnosed four years earlier. The authors, after presenting the clinical and diagnostic features of the patient, discuss the similarity of some pathogenetic features of the two diseases. They hypothesize a common pathogenetic immunological defect in the two diseases, probably caused by inhalation of silica.

Crohn Disease↗

Aluminium inhalation in sheep silicosis.

In prior studies, we and others have documented a significant reduction by surface chemistry modification in the biological activity of quartz. We further documented that aluminium lactate inhalation one month after quartz exposure significantly suppressed the silica-induced alveolitis, reduced the pathological process and decreased the retention of quartz in the lung tissue. In the present study, we evaluated the efficacy of aluminium inhalation in altering the silicosis process after disease was recognized by standard chest radiography. Twenty-four sheep were enrolled in the study. The 14 silica exposed sheep had an abnormal chest radiograph of the ILO category 1 or above after 3 years of 100 mg Minusil-5 in 100-ml saline intratracheal injections. Ten control sheep were exposed to saline intratracheal injections. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage. At month 36 of the study, all 14 sheep had an abnormal chest radiograph while the radiographs of controls remained normal. The sheep with silicosis had significantly reduced lung functions and increased cellularity, phospholipids and hyaluronan. These changes persisted during the next 12 months without exposure or treatment. At month 48 and at monthly intervals after, for 12 months, aerosol inhalations were carried out with saline alone for control and seven silicotic sheep and with 100 mg of aluminium lactate in 10 ml saline generated with a Bird Mark 8 pressure ventilator for the other seven silicotic sheep. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

The role of certain immunologic parameters in silicosis.

The paper presents some possibilities of estimating the immunologic aggression in silicosis in a group of 68 patients divided into three subgroups according to the evolutive stage of disease. The results were compared with the data obtained in a control group of 35 clinically healthy subjects not subjected to respiratory noxae. Parameters such as the immunogram (IgG, IgA IgM, IgD), the C3 complement, the circulating immune complexes (CIC) and the C reactive protein (CRP) were investigated using classical immunochemical methods. It was observed that the immunoglobulin titer presented a polyclonal increase. The mean values of C3 complement decreased in stages I and II of disease. The CIC level presented high mean values unrelated to the stage of the disease. The incidence of CRP was found high in stage III. It was demonstrated that there is no significant correlation between the humoral immunologic abnormalities and the radiologic changes or the depression of the pulmonary functional test. These changes suggest that the humoral immunologic abnormalities are not directly responsible for the lung changes in silicosis and cannot be used as a predictive indicator of the severity of the disease or of its progress. The data obtained showed a hyperreactivity of the humoral mediated immunity over the whole course of the disease thus supporting the assumption of an immunopathogenic mechanism in this disease.

Adult↗

Peritoneal silicosis.

A 73-year-old man with a clinical diagnosis of pulmonary silicosis (long-standing exposure to silica, pulmonary infiltrates, and flu-like symptoms) presented to the emergency room with fever, acute biliary colic, and cholelithiasis. The patient had a 2-year status postchemotherapy with complete remission of hepatic and splenic malignant lymphoma. At laparotomy we found studding of the undersurface of the diaphragm with multiple small dark nodules. Owing to the patient's history of previously treated abdominal malignant lymphoma, the lesions were grossly interpreted as abdominal lymphomatosis. The microscopic appearance of the lesions suggested silicotic nodules, which were confirmed by digital scanning electron microscopy and roentgenographic microanalysis performed on formalin-fixed, paraffin-embedded tissue. This is an unusual extrapulmonary pattern of peritoneal seeding in silicosis.

Aged↗

Study of lung antibodies in patients with silicosis.

The presence of lung antibodies was determined in a group of 68 patients with silicosis in various stages of evolution and in a control group of 35 healthy subjects, by the standard indirect immunofluorescent technique with fluorescent conjugate anti human gammaglobulin and monospecific fluorescent conjugates anti human IgG, IgA and IgM. In the group of patients investigated, lung antibodies were detected by means of fluorescent conjugate anti human gammaglobulin, in 47 cases of the 68 examined. As regards the investigations using monospecific fluorescent conjugates it was observed that all the 47 patients presented lung antibodies of the IgG class, 32 presented lung antibodies of the IgA class and 15 presented lung antibodies of the IgM class. The presence of lung antibodies in silicotic patients suggests the participation of acquired humoral immunity in the pathogeny of disease without, however, being directly responsible for the evolution of disease. The association of silicosis with various other autoimmune diseases pleads for the existence of an immune component in the evolution of this pneumoconiosis.

Autoantibodies↗

[Bronchoscopic diagnosis of central peribronchial lung cancer in silicosis and silicotuberculosis].

Examination of 315 lung cancer patients with silicosis or silicotuberculosis gave grounds for recognition of 3 variants of bronchial stenosis. The efficacy of bronchoscopic techniques was related both to anatomic variant of the tumor and primary tumor position against the involved bronchus lumen. Central peribronchial cancer in silicosis and silicotuberculosis has specific features: combination of true tumor stenosis with false rigidity of the trachea and large bronchi, advanced scar anthracotic deformity of the bronchi and diffuse atrophy of bronchial mucosa, distinctive pattern of metastatic spreading.

Adult↗

[Characteristics of the progression of silicosis under alpine conditions].

Siliceous dust during hypobaric hypoxia under the conditions of high mountains causes a rapid onset of silicosis in miners. Nodular silicosis types are prevalent. Lower activity of antioxidative protective enzymes and activated free radical oxidation and autoimmune responses are detectable.

Altitude↗

[The effect of anti basic fibroblast growth factor on the development of experimental silicosis bacillus].

Anti-bFGF serum was used to treat rabbit experimental silicosis. At 90 days, when experimental group was compared with control group, the number and size of the nodules in experimental group were much less and smaller than those in control group. Nodules in control group were mainly consist of fibroblast mixed with a small amount of collagen fiber, whereas nodules in experimental group were made up of macrophages. At 180 days, in addition to fibroblasts, there was II to III degree of collagen fiber in nodules of control group. Most of nodules in experimental group mainly contained macrophages. Fibroblasts of lung in fetal mice were cultured in vitro. The results showed that bFGF stimulated proliferation of fibroblast, whereas anti-bFGF serum inhibited fibroblast growth. It appeared that anti-bFGF serum actually blocked proliferation of fibroblast and fibrosis in rabbit experimental silicosis.

Animals↗

On the relationship between activation and breakdown of macrophages in the pathogenesis of silicosis (an overview).

Silica particles cause considerable damage to macrophages resulting in their eventual breakdown. At the same time, the development of silicosis involves a number of mechanisms associated with the activation of macrophages. In suggesting schemes for the pathogenesis of this disease many authors associate the central part with activation, completely neglecting damage to cells. Our experiments have shown, however, that much of the activation phenomena could be reproduced in vitro or in vivo by exposing macrophages to macrophage breakdown products. Alternatively, the secondary character of activation is demonstrated by the fact that it reveals itself only at silica doses which cause part of the cells to lose their viability in the same culture. Our data show that the range of macrophage activation phenomena which could be considered as secondary with respect to the breakdown of cells includes the production of neutrophil attractants, enhanced co-operation with T lymphocytes, increase in phagocytic activity, enhancement of cellular O2 consumption and peroxidation, an increase in the activity of dehydrogenases, reduction in the activity of 5'-nucleotidase, and some other effects. Although not denying that small silica doses may be able to exert a direct activating influence upon the macrophage we do, however, believe that the most important and primary role in the pathogenesis of silicosis is played by the damage to and the breakdown of this cell.

Animals↗

Mortality among persons with silicosis reported to disease surveillance systems in Michigan and New Jersey in the United States.

Michigan and New Jersey in the United States maintain silicosis disease registers. In 1988-1992, 372 cases of silicosis were confirmed in Michigan, and, in 1979-1992, 288 were confirmed in New Jersey. A proportionate mortality ratio (PMR) analysis was performed on data from 292 deceased silicotics. Increases in PMR values were found for nonmalignant respiratory disease (NMRD) and lung cancer. The PMR values for NMRD were statistically elevated in all the analyses. The overall proportionate cancer mortality ratio (PCMR) for lung cancer was 1.78 [95% confidence interval (95% CI) 1.22-2.61]. For patients having ever smoked cigarettes, the PCMR for lung cancer was 1.82 (95% CI 1.8-2.81). Never smoking silicotics had a lung cancer PCMR of 1.48 (95% CI 0.43-2.86). For those who had never applied for workers' compensation the corresponding PCMR was higher, 2.10 (95% CI 1.21-3.69), than for those who had applied, 1.45 (95% CI 0.70-2.99).

Confidence Intervals↗

Silica, silicosis and cancer in Finland.

Approximately 100 000 Finnish workers are currently employed in jobs and tasks that may involve exposure to airborne silica dust. The major industries involved are mining and quarrying; production of glass, ceramics, bricks and other building materials; metal industry, particularly iron and steel founding; and construction. Over 1500 cases of silicosis have occurred in Finland since 1935. Tuberculosis has been a frequent complication of silicosis. Results of studies from several countries strongly suggest that silica dust also causes lung cancer. The results of the relevant Finnish epidemiologic and industrial hygiene studies addressing cancer risk and exposure to quartz dust are summarized.

Confidence Intervals↗

[Histiocytosis X falsely diagnosed as silicosis].

The observation concerns a patient who was professionally exposed to silica dust. Radiologically he presented a diffuse interstitial infiltrate and clinically an obstructive syndrome with emphysem. The diagnosis of silicosis was made. The development was followed during 12 years without important modification of the X-ray or the respiratory functions. The patient died of a ruptured aortic aneurysm. At the autopsy the examination of the lungs permitted to exclude the initial diagnosis of silicosis and to conclude to an histiocytosis X. This diagnostic mistake allows to get on some radiological, clinical and epidemiological aspects, characteristic or these both pathologies.

Aged↗

[Genetic aspects of silicosis: polymorphic gene distribution frequency].

Electrophoresis and isoelectrofocusing were used to study polymorphism by 7 genetic loci: haptoglobin (Hp), proteinase inhibitor (PI), transferrin (TF), Vitamin D-transporting protein (GC), complement 3 (C3), phosphoglucomutase 1 (PGM1) and glyoxalase (GLO1) in 60 patients with silicosis and in 70 apparently healthy workers of the Dynamo plant. Comparison of the study groups by significant differences in the summary of the genetic information obtained suggests that 5 (Hp, C3, TF, PI, PGM1) of the 7 studied systems showed the hereditary features of silicosis. The gene carriers Hp*2, C3*F, PGM1*2-, PI*M1, TF*C1, TF*C16 TF*D, GC*R due to peculiar biochemical processes appear to have less adaptive potentialities and a greater likelihood of the disease on exposure to industrial factors.

Adult↗

The reawakening of national concern about silicosis.

From West Texas to West Virginia, from California to New York, in industries from oil refining to coal mining and work settings from foundries to shipyards, the United States is experiencing an epidemic of silicosis, a preventable disease. Silica sand has been linked to cancer, and the International Agency for Research on Cancer has named silica as a probable human carcinogen. This article analyzes the reawakening of national concern about silicosis and the social, economic, and epidemiologic factors that have led scientists, policy makers, industrial hygienist, and labor and industry representatives to reassess the danger that silica sand poses to the health of an estimated two million workers in this country.

History, 20th Century↗

[Acute silicosis. Clinical, radiologic, functional, and cytologic characteristics of the broncho-alveolar fluids. Observations of 6 cases].

We describe six cases of acute silicosis which were characterised by an intense exposure to pure silica; there was a rapid onset with diffuse abnormalities on the radiological image and severe respiratory abnormalities. The duration of occupational exposure to silica was four to eighteen years. Three patients presented with a cough associated with disabling dyspnoea (stage III and IV). The physical examination showed finger clubbing in three patients and rales and crepitations on auscultation in two patients. There was general debility in four of the cases with weight loss. The chest x-ray showed a rapid progress with confluence of the diffuse nodular opacities. Respiratory function tests showed a restrictive ventilatory defect (mean +/- standard error of mean: TLC 67 +/- 5%, Vital Capacity +/- 7%, FEV1 63.5 +/- 6%) and alteration in the transfer factor for carbon monoxide (DLCO: 49.5 +/- 5%). The initial broncho-alveolar lavage showed a lymphocytosis (23.6 +/- 4.2%) associated with an alveolar neutrophilia (7 +/- 2.5%). A lung biopsy was carried out in three patients and a transbronchial biopsy in one patient confirming the diagnosis of silicosis in three cases and of silicoproteinosis in one case. After a period of eighteen months to 14 years, four patients died either due to cardiopulmonary complications of their disease (two cases) or to intercurrent disorders (two cases). The last two patients are currently stable.

Adult↗

Scanning electron microscopy of the bronchial mucosa in some lung diseases using bronchoscopy specimens. A pilot study including cases of bronchial carcinoma, sarcoidosis, silicosis and tuberculosis.

In order to study the lung defence mechanisms and the mucociliary transport system scanning electron microscopy was performed on biopsy specimens obtained at bronchoscopy under local anaesthesia. There were great variations in the appearance of the cilitated epithelium from the large bronchi in 40 patients with bronchial carcinoma, sarcoidosis, silicosis, tuberculosis and other lung diseases. Areas with a low frequency of cilia were observed mainly in granulomatous disorders, and in silicosis, atypical cilia occurred abundantly. Squamous metaplasia with a complete loss of cilia was found in chronic bronchitis, bronchial carcinoma, after radiotherapy and in two of seven cases of sarcoidosis. Scanning electron microscopy seems to be an excellent method for studying the surface of the bronchial epithelium in many lung diseases, and may prove to be helpful in occupational medicine.

Adult↗

Subclinical signs of kidney dysfunction following short exposure to silica in the absence of silicosis.

Signs of kidney dysfunction detectable in urinary protein excretion were searched for in a group of 86 silica-exposed workers who were compared to 86 control subjects matched for age, smoking status and body mass index. No worker had any clinical, spirometric or radiographic sign of silicosis, and exposure duration averaged 15.2 months (range: 11-20). An increase in the urinary excretion of albumin, transferrin, retinol-binding protein and N-acetyl-beta-D-glucosaminidase was found in the exposed group, and the prevalences of pathological values were also elevated in this group. By contrast, both groups had similar serum levels of creatinine and beta 2-microglobulin. These results strongly suggest that occupational exposure to silica may lead to subclinical renal effects after less than 2 years and in the absence of silicosis.

Adult↗