silicon and Lung-Diseases

Epidemiological studies suggest strong association of lung disorders with occupational exposure to asbestos, silicon and arsenic. The chronic occupational exposure primarily through inhalation results in adverse outcome on the respiratory tract which may also be fatal. Although several mechanisms have attributed towards these diseases; the molecular pathogenesis is still unknown.. In this review, we investigated the plausible molecular mechanism based on current research that may identify the genetic and epigenetic susceptibility of respiratory disorders upon such occupational exposures in humans.. We considered genetic variants and epigenetic alterations associated with pulmonary exposure hazards leading to asbestosis, silicosis and arsenicosis. Our review is stringently based on the literatures available through peer-reviewed articles mostly published in the last 10 years. Relevant search were conducted using keywords like "occupational lung disorders" along with "asbestos", "silicon" and "arsenic".. Till September 2015, pubmed search yielded approximately 780 articles relating to asbestos exposure; 240 articles for silicon exposure and 60 articles for arsenic exposure. Extensive screening for genetic and epigenetic factors identified certain genes and related pathways that are important to determine the susceptibility of an individual towards such occupational exposure.. The link between genotype and phenotype and its association with disease susceptibility is very complex in nature due to several factors like person's environment, lifestyle and nutritional status. The epigenome is dynamic as well as reversible and can be reshaped further by certain dietary components throughout its life. In the present review, we have addressed the role of molecular pathogenesis of occupational lung diseases based on the genetic variability and epigenetic alterations and also attempted to highlight the promising aspect of dietary interventions to counter toxic outcomes upon occupational exposure to asbestos, silicon or arsenic.

Topics: Animals; Arsenic; Asbestos; Genetic Predisposition to Disease; Humans; Lung Diseases; Occupational Exposure; Silicon

The article presents the influence of silicon carbide upon an organism, on the basis of the publications which, according to Chemical Abstracts, appeared on this subject from 1944 until 1987. The insolubility of silicon carbide, in the liquids of an organism and its indigestibility are indicated. A connection is presented between the size and shape of micrograins and the probability of tumor formation in rats; and the difference between silicon carbide and other dusts in the absorption of x-rays, inhibition of the TTC-dehydrogenase activity, collagenisation of lesions, carcinogenicity are also presented. The problem of interpretation of radiological images of lungs in people exposed to the influence of carborundum dust is dealt with. The biological inertness of silicon carbide is questioned.

Topics: Animals; Carbon; Carbon Compounds, Inorganic; Humans; Lung Diseases; Neoplasms; Neoplasms, Experimental; Occupational Diseases; Silicon; Silicon Compounds

A 44-year-old woman was admitted to hospital with end-stage renal failure, productive cough, and decreased exercise tolerance. She had owned nine cats, which resulted in long-term exposure (18 years) to silica-containing bentonite cat litter. High-resolution computed tomography of the chest showed micronodular lesions in the lungs, and mild mediastinal lymphadenopathy. A lung biopsy revealed multinucleated giant cells, some of which had birefringent material and Schaumann bodies. X-ray photoelectron spectroscopy revealed the presence of silicon in the lung biopsy specimen, as well as in the patient's cat litter. The pulmonary condition was suggestive of sarcoid-like lung disease, rather than silicosis, sarcoidosis, or hypersensitivity pneumonitis, according to the clinicopathological findings. Renal failure appeared to be a result of chronic hypercalcemia due to extrarenal calcitriol overproduction in activated alveolar macrophages. Ultimately, the patient was diagnosed with sarcoid-like lung disease complicated by end-stage renal failure from exposure to bentonite cat litter. Therapy with steroids, in addition to elimination of the bentonite cat litter exposure, resulted in a significant improvement in the health condition. At a follow-up visit after 4 months, an almost complete resolution of the lung lesions and a significant improvement in renal function were observed.

Topics: Bentonite; Calcitriol; Female; Humans; Kidney Failure, Chronic; Lung Diseases; Sarcoidosis; Silicon; Silicon Dioxide; Skin Diseases

There is an urgent need for new materials to treat bacterial infections. In order to improve antibacterial delivery, an anti-infective nanomaterial is developed that utilizes two strategies for localization: i) a biodegradable nanoparticle carrier to localize therapeutics within the tissue, and ii) a novel tandem peptide cargo to localize payload to bacterial membranes. First, a library of antibacterial peptides is screened that combines a membrane-localizing peptide with a toxic peptide cargo and discovers a tandem peptide that displays synergy between the two domains and is able to kill Pseudomonas aeruginosa at sub-micromolar concentrations. To apply this material to the lung, the tandem peptide is loaded into porous silicon nanoparticles (pSiNPs). Charged peptide payloads are loaded into the pores of the pSiNP at ≈30% mass loading and ≈90% loading efficiency using phosphonate surface chemistry. When delivered to the lungs of mice, this anti-infective nanomaterial exhibits improved safety profiles over free peptides. Moreover, treatment of a lung infection of P. aeruginosa results in a large reduction in bacterial numbers and markedly improves survival compared to untreated mice. Collectively, this study presents the selection of a bifunctional peptide-based anti-infective agent and its delivery via biodegradable nanoparticles for application to an animal model of lung infection.

Topics: Animals; Anti-Bacterial Agents; Lung Diseases; Mice; Nanoparticles; Peptides; Porosity; Pseudomonas aeruginosa; Pseudomonas Infections; Silicon

Two of the biggest challenges in medicine today are the need to detect diseases in a noninvasive manner and to differentiate between patients using a single diagnostic tool. The current study targets these two challenges by developing a molecularly modified silicon nanowire field effect transistor (SiNW FET) and showing its use in the detection and classification of many disease breathprints (lung cancer, gastric cancer, asthma, and chronic obstructive pulmonary disease). The fabricated SiNW FETs are characterized and optimized based on a training set that correlate their sensitivity and selectivity toward volatile organic compounds (VOCs) linked with the various disease breathprints. The best sensors obtained in the training set are then examined under real-world clinical conditions, using breath samples from 374 subjects. Analysis of the clinical samples show that the optimized SiNW FETs can detect and discriminate between almost all binary comparisons of the diseases under examination with >80% accuracy. Overall, this approach has the potential to support detection of many diseases in a direct harmless way, which can reassure patients and prevent numerous unpleasant investigations.

Topics: Asthma; Breath Tests; Humans; Lung Diseases; Nanowires; Silicon; Volatile Organic Compounds

Exposure to ambient particulate matter (PM) has been associated with reduced lung function. Elemental components of PM have been suggested to have critical roles in PM toxicity, but their contribution to respiratory effects remains under-investigated. We evaluated the effects of traffic-related PM(2.5) and its elemental components on lung function in two highly exposed groups of healthy adults in Beijing, China.. The Beijing Truck Driver Air Pollution Study (BTDAS) included 60 truck drivers and 60 office workers evaluated in 2008. On two days separated by 1-2 weeks, we measured lung function at the end of the work day, personal PM(2.5), and nine elemental components of PM(2.5) during eight hours of work, i.e., elemental carbon (EC), potassium (K), sulfur (S), iron (Fe), silicon (Si), aluminum (Al), zinc (Zn), calcium (Ca), and titanium (Ti). We used covariate-adjusted mixed-effects models including PM(2.5) as a covariate to estimate the percentage change in lung function associated with an inter-quartile range (IQR) exposure increase.. The two groups had high and overlapping exposure distributions with mean personal PM(2.5) of 94.6 μg/m³ (IQR: 48.5-126.6) in office workers and 126.8 μg/m³ (IQR: 73.9-160.5) in truck drivers. The distributions of the nine elements showed group-specific profiles and generally higher levels in truck drivers. In all subjects combined, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) did not significantly correlate with PM(2.5). However, FEV1 showed negative associations with concentrations of four elements: Si (-3.07%, 95% CI: -5.00; -1.11, IQR: 1.54), Al (-2.88%, 95% CI: -4.91; -0.81, IQR: 0.86), Ca (-1.86%, 95% CI: -2.95; -0.76, IQR: 1.33), and Ti (-2.58%, 95% CI: -4.44; -0.68, IQR: 0.03), and FVC showed negative associations with concentrations of three elements: Si (-3.23%, 95% CI: -5.61; -0.79), Al (-3.26%, 95% CI: -5.73; -0.72), and Ca (-1.86%, 95% CI: -3.23; -0.47). In stratified analysis, Si, Al, Ca, and Ti showed associations with lung function only among truck drivers, and no significant association among office workers.. Selected elemental components of PM(2.5) showed effects on lung function that were not found in analyses of particle levels alone.

Topics: Adult; Air Pollution; Aluminum; Calcium; China; Environmental Illness; Female; Forced Expiratory Volume; Humans; Inhalation Exposure; Lung; Lung Diseases; Male; Occupations; Particulate Matter; Respiratory Mucosa; Silicon; Statistics as Topic; Titanium; Urban Health; Vehicle Emissions; Vital Capacity

To investigate the relationship between dust exposure and annual change in lung function among employees in Norwegian silicon carbide (SiC) plants using a quantitative job exposure matrix (JEM) regarding total dust.. All employees, 20-55 years of age by inclusion (n=456), were examined annually for up to 5 years (1499 examinations). Spirometry was performed at each examination, and a questionnaire encompassing questions of respiratory symptoms, smoking status, job and smoking history, and present job held was completed. A JEM was constructed based on 1970 personal total dust exposure measurements collected during the study period. The association between lung function and total dust exposure was investigated using linear mixed models.. The annual change in forced expiratory volume (FEV) in one second per squared height, FEV1/height(2), per mg/m(3) increase in dust exposure was -2.3 (95% CI -3.8 to -0.79) (mL/m(2))×year(-1). In an employee of average height (1.79 m) and exposure (1.4 mg/m(3)) the estimated contribution to the annual change in FEV1 associated with dust was 10.4 mL/year. The annual change in FEV1/height(2) in current, compared with non-smokers was -1.9 (-7.2 to 3.4) (mL/m(2))×year(-1). The estimated overall annual decline in FEV1 among current and non-smokers in the highest exposed group was -91.2 (-124.3 to -58.1) (mL/m(2))×year(-1) and -49.0 (-80.2 to -17.8) (mL/m(2))×year(-1), respectively.. Dust exposure, expressed by a quantitative JEM, was found to be associated with an increased yearly decline in FEV1 in employees of Norwegian SiC plants.

Topics: Adult; Carbon Compounds, Inorganic; Dust; Female; Forced Expiratory Volume; Humans; Industry; Inhalation Exposure; Lung; Lung Diseases; Male; Middle Aged; Norway; Occupational Diseases; Occupational Exposure; Particulate Matter; Silicon; Silicon Compounds; Smoking; Spirometry; Surveys and Questionnaires

To evaluate a large area, cesium iodide amorphous silicon flat-panel detector (CsI/a-Si) at 3 tube voltages to detect simulated interstitial lung disease, nodules, and catheters.. Simulated interstitial lung disease, nodules, and catheters were superimposed over a chest phantom. Images were generated at 125 kVp, 90 kVp, and 70 kVp at the same surface dose and reduced effective dose equivalent for 90 kVp and 70 kVp and printed on hard copies. Fifty-four thousand observations were analyzed by receiver operating characteristic (ROC).. Detectability of linear, miliary, reticular pattern, and nodules over lucent lung as well as of catheters and nodules over obscured chest areas increased at 90 and/or 70 kVp with higher Az values; however, only it was statistically significant for reticular pattern at 70 kVp and nodules at 90 kVp compared with 125 kVp (P < 0.05). The detection of ground-glass pattern was worse at lower kVp (P > 0.05).. For most simulated patterns, differences in diagnostic performance at 70 kVp/90 kVp and 125 kVp were not significant, except for reticular pattern and nodules over lucent lung.

Topics: Cesium; Humans; Iodides; Lung; Lung Diseases; Phantoms, Imaging; Radiation Dosage; Radiographic Image Enhancement; Silicon; X-Ray Intensifying Screens

To compare observer performance by using soft-copy images produced by an amorphous silicon flat-panel-detector system and a storage-phosphor system for the detection of simulated chest lesions.. To test the diagnostic performance of these two systems, four types of simulated lesions (nodules, micronodules, lines, and reticular opacities) were superimposed over an anthropomorphic chest phantom. Digital chest radiographs were acquired with amorphous silicon flat-panel-detector (3-K [K = 1,000] matrix, 12 bits) and storage-phosphor radiography (4-K matrix, 10 bits). Six board-certified radiologists evaluated soft-copy images on a high-resolution video monitor (2,048 x 2,560 x 8 bits). A total of 14,400 observations were analyzed in terms of receiver operating characteristics.. Average performance in terms of nodule detection was significantly better (P <.05) with the flat-panel-detector system than with the storage-phosphor system. For micronodules, lines, and reticular opacities, no significant detection differences in averaged performance were found between the two detector systems.. In the evaluation of soft-copy images, the amorphous silicon detector system appears to be superior to the storage-phosphor system for the detection of pulmonary nodules.

Topics: Lung Diseases; Phantoms, Imaging; Radiography; Radiology Information Systems; Silicon

The objective of this study was to compare the diagnostic performance of a digital large-area silicon flat-panel detector with that of a conventional screen-film system in clinical chest imaging using abnormal findings documented by CT as the reference standard.. Eighty patients (46 men and 34 women; age range,18-91 years; mean age, 63 years) who underwent CT of the chest were examined with the new digital radiography system, which is based on a 43 x 43 cm silicon flat-panel detector, and with a conventional screen-film system, which is used routinely in clinical practice. Posteroanterior and lateral radiographs were obtained. Four radiologists analyzed the digital and conventional images separately for chest abnormalities and rated the images using a five-level scale of confidence; CT was used as the reference standard. Diagnostic value was assessed using receiver operating characteristic curves for each abnormality.. No significant differences were found between the area under the receiver operating characteristic curve of the digital and that of the conventional radiography method for almost all investigated criteria. The only exception was mediastinal abnormalities, for which the digital method provided better results than the conventional method (p < 0.05).. The diagnostic performance of the new large-area silicon flat-panel detector is equivalent or superior to that of the conventional screen-film system for clinical chest imaging and can replace conventional radiography systems. This new technology offers transmission and storage possibilities inherent to digital radiology that would facilitate daily practice and reduce the initial high costs in the long-term.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Female; Humans; Lung Diseases; Male; Middle Aged; Observer Variation; Radiographic Image Enhancement; Radiography, Thoracic; ROC Curve; Silicon; Tomography, X-Ray Computed; X-Ray Intensifying Screens

Experimental and clinical evaluation of a digital flat-panel X-ray system based on cesium iodide (CsI) and amorphous silicon (a-Si).. Performance of a prototype detector was compared with conventional screen-film radiography (SFR) using several phantom studies. Foreign bodies, fractures, osteolyses, and pulmonary lesions were analyzed. Additionally, 120 patients were studied prospectively, resulting in 400 comparative X-ray studies. The flat-panel detector was exposed with standard dose and with a dose reduction of up to 75%. Detector size was 15 x 15 cm, pixel matrix was 1 x 1 k with a pixel size of 143 microns. Modulation-transfer function was determined to be 18% at the maximum spatial resolution of 3.5 lp/mm.. The diagnostic results achieved with the digital detector were similar to those of conventional SFR, even at reduced radiation exposure. A potential for dose reduction was observed: 50% with respect to osteoarthrosis and fractures, and 75% for determining bony alignment.. This new technology can be used in thoracic and skeletal radiography. A significant dose reduction is possible, depending on the suspected disease.

Topics: Animals; Bone Diseases; Cesium; Foreign Bodies; Humans; Iodides; Lung Diseases; Phantoms, Imaging; Radiation Dosage; Radiographic Image Enhancement; Silicon; Swine; X-Ray Intensifying Screens

Topics: Dust; Lung Diseases; Silicon

A 70-year-old man with a 10-year history of seal engraving presented with exertional dyspnea and dry coughing. Chest roentgenograms showed an interstitial shadow and bilateral progressively enlarging bullae. Open lung biopsy led to the diagnosis of idiopathic interstitial pneumonia (Type B). The size of bullae usually does not change, so cases such as this are rare because the bullae continued to expand subacutely. Persistent stimulation by the inhaled A1 and Si may have played a role in the pathogenesis of this condition.

Topics: Aged; Aluminum; Cysts; Humans; Lung Diseases; Lung Diseases, Interstitial; Male; Occupational Diseases; Occupational Exposure; Pneumothorax; Silicon

When rat (female Wistar) lungs were lavaged (bronchoalveolar lavage, BAL) six times with physiological saline, approximately the same number of alveolar macrophages (AM) were found in the first and second BAL, whereas in the third fourth, fifth, and sixth BAL, the number of AM decreased exponentially. Morphometric counting of the number of AM in histological sections of lung tissue showed that only 14% of the AM population had been recovered by BAL. Although additives to the BAL fluid such as lidocaine and/or fetal calf serum increased the AM count in the first washing considerably, the total number of AM washed out remained unaltered. Addition of the phagocytosis stimulant zymosan increased the AM count in BAL by a factor of more than 2. On stimulation of the lungs with an inert dust (silicon carbide), the AM count in the BAL and the lung was only slightly increased 8 weeks after intratracheal instillation. In contrast, after exposure to fibrogenic and cytotoxic quartz, the AM count in BAL and lung was significantly increased, and the recovery of AM had also increased by a factor of approximately 2. The experiments show that it is the micromilieu of the alveoli and the condition of the AM (certain physiological activation states, such as phagocytic activity) that essentially determine the degree of recovery.

Topics: Animals; Bronchoalveolar Lavage Fluid; Carbon; Carbon Compounds, Inorganic; Cell Count; Female; Lidocaine; Lung Diseases; Macrophages, Alveolar; Quartz; Rats; Rats, Wistar; Serum Albumin, Bovine; Silicon; Silicon Compounds; Sodium Chloride; Zymosan

Topics: Aluminum; Cobalt; Electron Probe Microanalysis; Humans; Lung; Lung Diseases; Occupational Diseases; Silicon

A comparative study was made of the action of 5 intratracheally introduced dusts (of manganese, silicon, potassium, natrium, calcium, fluorine, and iron) on the cardio-respiratory system. A more marked biologic activity of the hard component of welding aerosols with a high content of fluorine, potassium and soluble manganese compounds was established. This was proved by structural damages, such as atelectasis, emphysema, bronchiectasis in the lungs, dystrophic developments in the contractual myocardium, a sharp decrease in the luminescent intensity of the adrenergic terminals in the myocardium. All the welding dust samples did not display a fibrogenous activity in any degree.

Topics: Aerosols; Animals; Bronchial Diseases; Dust; Fluorine; Heart Diseases; Iron; Lung Diseases; Male; Manganese; Occupational Exposure; Potassium; Rats; Silicon; Sodium; Welding

An animal inhalation study was initiated to study the chronic biological effects of inhalation of short chrysotile asbestos fibers. Rats and monkeys were exposed for 18 months, 7 hr/day, 5 days/week to a specially prepared, chrysotile asbestos aerosol. Based upon daily chamber measurements, the mean concentration of fibers in the chamber air was 1.0 mg/m3. By phase contrast microscopy, the number of fibers greater than 5 micron in length was determined to be 0.79 fiber per cubic centimeter. Rats were autopsied for pathological and histochemical examination at 1, 3, 6, 12, 18, and 24 months after initiating exposures. No significant differences in the histochemical data were seen between the exposed and control groups. Gross and histopathologic examination of exposed and control groups of rats indicated no compound-related lesions, including fibrosis. Open lung biopsies were performed on the chrysotile-exposed and the control monkeys 28 months after initiating exposures. Histopathologic evaluation of the lung biopsy tissue showed the presence of asbestos bodies adjacent to the terminal bronchioles of the asbestos-exposed monkeys. There was no observed fibrosis in pulmonary tissue. All monkeys are being maintained for an indefinite period and observed for signs of latent pulmonary disease.

Topics: Aerosols; Animals; Asbestos; Asbestos, Serpentine; Body Weight; Dust; Lung; Lung Diseases; Macaca fascicularis; Male; Microscopy, Electron, Scanning; Organ Size; Particle Size; Rats; Rats, Inbred Strains; Silicon; Species Specificity; Time Factors

An infant dying with pulmonary hypertension had a pulmonary vessel foreign body vasculitis as identified by light microscopy and characterized ultrastructurally by scanning electron microscopy and energy-dispersive x-ray analysis. The inclusions were of two distinct types: those containing silicon and titanium, and others consisting of talc. The possible sources of these inclusions and the importance of considering foreign body vasculitis in the pathogenesis of clinically idiopathic pulmonary hypertension are discussed.

Topics: Humans; Hypertension, Pulmonary; Infant, Newborn; Infant, Newborn, Diseases; Lung Diseases; Male; Silicon; Talc; Titanium; Vasculitis

Topics: Adult; Bronchial Arteries; Embolization, Therapeutic; Female; Hemoptysis; Humans; Lung Diseases; Male; Rubber; Silicon

Topics: Animals; Heart Diseases; Humans; Lung Diseases; Occupational Diseases; Rats; Silanes; Silicon

Topics: Arsenic; Chemistry Techniques, Analytical; Humans; Lung; Lung Diseases; Neutron Activation Analysis; Neutrons; Radioisotopes; Radiometry; Silicon

Topics: Antifoaming Agents; Edema; Ethanol; Lung Diseases; Pulmonary Edema; Silicon

Topics: Aerosols; Edema; Lung Diseases; Pulmonary Edema; Silicon; Silicones