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Effects of quartz, airborne particulates and fly ash fractions from a waste incinerator on elastase release by activated and nonactivated rabbit alveolar macrophages.

Elastase release from cultured, activated and nonactivated rabbit alveolar macrophages (AM) was investigated after stimulation by different environmentally related mineral dusts (50-1000 micrograms/10(6) cells). Eight different dusts were analyzed for element contents and grain size: one rural and three urban airborne dusts, a coarse and a fine fraction of a sieved waste incinerator fly ash, a sonicated coarse fly ash fraction, and the standard quartz dust DQ 12. The fine fly ash fraction, the sonicated coarse fly ash fraction, and the quartz dust DQ 12 enhanced elastase release by activated AM. Only one of the tested airborne dusts effected a comparable elastase release. The untreated coarse fraction of the fly ash did not cause a significant increase of extracellular elastase activities. Elastase release was dependent on particle numbers and chemical composition and correlated best with barium and tin contents. Nonactivated AM released higher elastase activities than activated AM at low-dose levels. The possible role of dust-induced elastase secretion in the pathogenesis of emphysema is discussed.

Air Pollutants↗

PubMed2002

Time course of quartz and TiO(2) particle-induced pulmonary inflammation and neutrophil apoptotic responses in rats.

Apoptosis, or programmed cell death, has been reported to play an important role in the resolution of pulmonary inflammation. This study was undertaken to investigate the role of apoptosis in resolving particle-induced lung inflammatory responses in exposed rats, using a dose-response / time course experimental design. Groups of rats were exposed via intratracheal instillation to 0, 0.5, 1, 5, 10, or 50 mg/kg body weight of quartz (i.e., crystalline silica) particles or to 0, 0.5, 1, 5, 10, 20, or 50 mg/kg of pigment-grade titanium dioxide (TiO(2)) particles and evaluated for lung inflammation parameters and evidence of apoptosis of inflammatory cells at 24, 48, 72, or 168 hours post exposure. At each post exposure evaluation period, bronchoalveolar lavage (BAL)-recovered cells from control and particle-exposed rats were assessed for apoptosis using 4 different techniques. The results in silica-exposed rats demonstrated a significant dose-related increase in inflammation concomitant with apoptosis of pulmonary inflammatory cells at 24 to 48 hours post exposure. At later postexposure time points, both the silica-induced inflammatory responses and apoptotic levels of inflammatory cells at higher doses (i.e., >or= 5 mg/kg) were reduced but persisted through 1 week. TUNEL (TdT-mediated dUTP nick end-labeling) assay studies confirmed that the vast majority of apoptotic cells were neutrophils. In contrast, titanium dioxide particle exposures produced transient pulmonary inflammation but only small measurable and nonsignificant apoptotic responses at higher exposure concentrations. These results suggest that the sustained lung inflammatory response in rats exposed to >or= 5 mg/kg silica may be related to the ineffectiveness of the normal apoptotic mechanisms associated with resolution of inflammation. However, because quartz particles are known to be cytotoxic to alveolar macrophages and other lung cells, normal apoptotic mechanisms may have limited utility for resolving particle-induced inflammation, particularly because silica may not be representative of other particle-types. Alternatively, it seems unlikely that apoptosis served to promote silica-induced lung inflammatory responses because the initial increase of apoptosis in inflammatory cells was subsequently correlated with a reduction of the pulmonary inflammatory response in silica-exposed rats. The findings from this in vivo study demonstrate that the neutrophil, and not the alveolar macrophage, is the primary inflammatory cell-type that undergoes apoptosis in response to particles. Furthermore, at doses causing similar degrees of inflammation at 24 hours post exposure, the magnitude of apoptosis induced by silica is significantly larger than that induced by TiO(2), indicating that there are potency differences in lung inflammation as well as apoptotic responses among different particle-types.

Animals↗

PubMed1988

ESR evidence for the hydroxyl radical formation in aqueous suspension of quartz particles and its possible significance to lipid peroxidation in silicosis.

Electron spin resonance (ESR) spectrum of the hydroxyl (.OH) radical spin adduct with the spin trap 5,5-dimethyl-1-pyrroline-N-oxide has been obtained in suspensions of freshly ground quartz particles. The concentration of the spin adduct (and hence of the .OH radicals) increases with the amount of grinding. The dust's potential for the generation of the .OH radicals is maximum when fresh (i.e., immediately after grinding) and decreases to 50% in about a day on storage in air. Studies involving metal chelates indicate that the .OH radical formation involves mainly the silica surface and H2O rather than the Fenton reaction. The results suggest that hydroxyl radical reaction(s) could be important in the lipid peroxidation and fibrogenicity by quartz dust, particularly in acute silicosis.

Electron Spin Resonance Spectroscopy↗

PubMed1993

Visual safety of quartz linear lamps.

A quartz linear lamp (QLL) is a compact infra-red (i.r.) heating lamp. It consists of a tungsten filament in a quartz envelope, which for space heating purposes is surrounded by a ruby coloured filter. The filament runs at about 2400 K and produces i.r. radiation with a peak output at 1200 nm. The lamps are widely used for space heating and are normally fitted with a parabolic reflector. There are no statutory criteria for potential visual hazards resulting from the use of such lamps in the U.K. The ACGIH has produced a provisional set of rules on light and near i.r. This paper reviews potential hazards to the eye in the context of the ACGIH rules and the output of QLL heaters. The heaters produce no u.v. or blue light hazards. The brightness and heat of the lamp is sufficient to produce an aversion response which will prevent retinal thermal damage from inadvertent viewing. The probability of retinal thermal injury from an i.r.-A image focused on the retina is examined and it is shown that there is no risk at normal viewing distances. To prevent any risk of cataractogenesis, the rules provide for an upper limit of irradiance (TLV) at the eye of 100 W m-2 in the i.r.-A band; the paper examines the potential hazard from longer wavelengths and concludes that they do not present a hazard with this type of heating. The conclusion is that QLL heaters used for space heating in accordance with manufacturer's instructions present no hazard to the eye.

Eye↗

PubMed2002

Estimating the quartz exposure of South African gold miners.

The possibility that dust and silica exposure estimates in epidemiological studies of South African gold miners have been underestimated has been postulated for some years. These exposure estimates were obtained by converting particle number concentrations measured with konimeters and thermal precipitators to respirable mass concentrations, primarily on theoretical considerations. A detailed review of the methodology has revealed that the theoretically based dust and silica estimates were probably underestimated. In the absence of systematic side-by-side thermal precipitator and modern respirable mass measurements in the South African gold mines, the true relationship between the respirable mass concentrations and the theoretically derived concentrations cannot be known. However, with many uncertainties, we estimate that the quartz exposures of South African miners derived from past theoretically based conversions from particle number to respirable mass underestimate the actual quartz exposures by a factor of about 2.

Dust↗

PubMed2005

Comparison of direct (X-ray diffraction and infrared spectrophotometry) and indirect (infrared spectrophotometry) methods for the analysis of alpha-quartz in airborne dusts.

In this study, the alpha-quartz contents measured by different analytical techniques (X-ray diffraction, direct method; and infrared spectrophotometry, direct and indirect methods) were compared. The analyses were carried out on filters sampled in an industrial setting by means of a Dorr-Oliver cyclone. To verify the methodology used, filters loaded with pure alpha-quartz were also analysed. By and large, the agreement between the two direct methods was close on average, but on the basis of a comparison of the individual results, considerable differences exist. In absolute value, the mean relative deviation between the two techniques was <25% in only 47.8% of the cases. The results obtained by the indirect method (infrared) were on average 13% lower than the results obtained by the two direct methods with a more important difference (23%) for samples where calcite was identified by X-ray diffraction in comparison with those where it was not (8%). This underestimation, which was not owing to dust losses during preparation, is probably explained by the elimination of organic compounds during dust calcinations or by the transformation of mineral compounds. The indirect method introduces additional sample handling operations with more risk of material loss. When the quantity of calcined material was <0.4 mg, the weighing operations necessary to correct any losses of material resulted in considerable variability. In terms of overall uncertainty, it would be better in this case not to carry out correction and to employ an operating mode favouring the recovery of a maximum of material while accepting a bias of about 5-7%.

Air Pollutants↗

PubMed1991

Graphitized carbon black in quartz tubes for the sampling of indoor air nicotine and analysis by microwave thermal desorption-capillary gas chromatography.

Nicotine in a smoky indoor air environment can be determined using graphitized carbon black as a solid sorbent in quartz tubes. The temperature stability, high purity, and heat absorption characteristics of the sorbent, as well as the permeability of the quartz tubes to microwaves, enable the thermal desorption by means of microwaves after active sampling. Permeation and dynamic dilution procedures for the generation of nicotine in the vapor phase at low and high concentrations are used to evaluate the performances of the sampler. Tube preparation is described and the microwave desorption temperature is measured. Breakthrough volume is determined to allow sampling at 0.1-1 L/min for definite periods of time. The procedure is tested for the determination of gas and paticulate phase nicotine in sidestream smoke produced in an experimental chamber.

Air Pollutants↗

PubMed2001

Evaluation of environmental dose at JCO using luminescence from quartz stimulated by blue light.

The environmental dose due to the recent nuclear accident at JCO, Japan, was estimated using luminescence optically stimulated from unheated quartz. Two methods originally developed for dating analysis, the single aliquot additive dose method and the single aliquot regeneration added dose method, were employed to confirm the dose rate. Consistent results were obtained from both methods and from thermoluminescence measurements. Although the dose rate values had lower precision than can be obtained from heated materials, it is suggested that luminescence from sedimentary quartz can usefully be employed in retrosepective dosimetry.

Humans↗

PubMed2002

Mechanical effects of electrodes on the vibrations of quartz crystal plates.

A system of approximate first-order equations is extracted from an infinite system of 2-D equations for piezoelectric crystal plates with thickness-graded material properties, which is deduced from the 3-D equations of linear piezoelectricity. These equations are used to study mechanical effects on the thickness-shear (TS), flexural (F), and face-shear (FS) vibrations of an AT-cut quartz plated with two identical electrodes. Dispersion curves are calculated from the present 2-D equations as well as the 3-D equations. The comparison of these curves shows that the agreement is very close for all three frequency branches of TS, F, and FS modes in a range up to the 1.5 times the fundamental TS frequency and for gold and aluminum electrodes with R, the ratio of the mass of the electrodes to that of the plate, equal to 0.05. without introducing any correction factors. In order to assess electrode effects, spectra of omega vs. a/bq (length-to-thickness ratio of the quartz) are computed for plates with gold and aluminum electrodes and different R ratios. And the spectrum of omega vs. R is computed for plates with aluminum electrodes and a given a/bq ratio. For a plate with gold electrodes, the frequencies of predominant TS, F, and FS modes are decreasing as R increases, but the amount of frequency changes for the TS mode is much greater than those for the other two modes. However, for a plate with aluminum electrodes, the frequencies of the TS and FS modes are decreasing, but those of the F modes are increasing as R increases.

Aluminum↗

PubMed2002

Metasomatic origin of quartz-pyroxene rock, Akilia, Greenland, and implications for Earth's earliest life.

A quartz-pyroxene rock interpreted as a banded iron formation (BIF) from the island of Akilia, southwest Greenland, contains (13)C-depleted graphite that has been claimed as evidence for the oldest (>3850 million years ago) life on Earth. Field relationships on Akilia document multiple intense deformation events that have resulted in parallel transposition of Early Archean rocks and significant boudinage, the tails of which commonly form the banding in the quartz-pyroxene rock. Geochemical data possess distinct characteristics consistent with an ultramafic igneous, not BIF, protolith for this lithology and the adjacent schists. Later metasomatic silica and iron introduction have merely resulted in a rock that superficially resembles a BIF. An ultramafic igneous origin invalidates claims that the carbon isotopic composition of graphite inclusions represents evidence for life at the time of crystallization.

Carbon Isotopes↗

PubMed1999

Effect of ionic strength on initial interactions of Escherichia coli with surfaces, studied on-line by a novel quartz crystal microbalance technique.

A novel quartz crystal microbalance (QCM) technique was used to study the adhesion of nonfimbriated and fimbriated Escherichia coli mutant strains to hydrophilic and hydrophobic surfaces at different ionic strengths. This technique enabled us to measure both frequency shifts (Deltaf), i.e., the increase in mass on the surface, and dissipation shifts (DeltaD), i.e., the viscoelastic energy losses on the surface. Changes in the parameters measured by the extended QCM technique reflect the dynamic character of the adhesion process. We were able to show clear differences in the viscoelastic behavior of fimbriated and nonfimbriated cells attached to surfaces. The interactions between bacterial cells and quartz crystal surfaces at various ionic strengths followed different trends, depending on the cell surface structures in direct contact with the surface. While Deltaf and DeltaD per attached cell increased for nonfimbriated cells with increasing ionic strengths (particularly on hydrophobic surfaces), the adhesion of the fimbriated strain caused only low-level frequency and dissipation shifts on both kinds of surfaces at all ionic strengths tested. We propose that nonfimbriated cells may get better contact with increasing ionic strengths due to an increased area of contact between the cell and the surface, whereas fimbriated cells seem to have a flexible contact with the surface at all ionic strengths tested. The area of contact between fimbriated cells and the surface does not increase with increasing ionic strengths, but on hydrophobic surfaces each contact point seems to contribute relatively more to the total energy loss. Independent of ionic strength, attached cells undergo time-dependent interactions with the surface leading to increased contact area and viscoelastic losses per cell, which may be due to the establishment of a more intimate contact between the cell and the surface. Hence, the extended QCM technique provides new qualitative information about the direct contact of bacterial cells to surfaces and the adhesion mechanisms involved.

Bacterial Adhesion↗

PubMed1975

Adsorption of syndiotactic and isotactic poly(2-vinylpyridine 1-oxide) on quartz surface.

Poly(2-vinylpyridine 1-oxide) inhibits the cytotoxic effects of quartz in cell cultures but the syndiotactic polymer behaves differently from the isotactic and atactic polymers. In each case approximately 1-0 mg/m2 of the polymer represents the adsorption maximum. No difference has been found between the adsorption isotherms of the stereoisomeric polymers or the stability of the adsorbed layers. The layers are not removed by repeated washing. The observations do not support the theory that the poly(2-vinylpyridine 1-oxide) is active because it coats the quartz surface.

Adsorption↗

PubMed1985

A spin label study of the effects of asbestos, quartz, and titanium dioxide dusts on the bovine erythrocyte membrane.

The effects of five UICC asbestos samples, titanium dioxide, and quartz on the bovine red cell membrane have been studied in erythrocyte ghosts by the spin labelling technique. Analysis of the electron paramagnetic resonance (EPR) spectra of two sulphydryl reactive spin labels and one fatty acid spin label in red cell ghosts showed modifications in membrane protein after asbestos treatment but no alterations in membrane lipids. In experiments with quartz no membrane changes were noted but titanium dioxide altered the proteins bound with the protein reactive spin label used in the present study. The possible mechanism for these effects is discussed.

Animals↗

PubMed1991

Extracellular matrix components in bronchoalveolar lavage fluid in quartz exposed rats.

To investigate the long term effects of quartz, bronchoalveolar lavage (BAL) and analysis of lung silica were performed in rats (n = 20) one, four, and 12 months after exposure to intratracheally instilled crystalline silica. Total and relative concentrations of silica in the lungs were highest one month after exposure. At this time BAL fluid concentrations of total cells, macrophages, and lymphocytes increased five to 10-fold compared with saline instilled controls (n = 19). The number of polymorphonuclear cells (PMNs) increased about 200-fold. The increased number of PMNs persisted during the year. Furthermore, albumin and fibronectin concentrations increased continually during the year, about two to fivefold the values of controls. Hyaluronan, by contrast, increased during the four month period (about eightfold) but decreased after one year to the one month concentration. Phospholipids in BAL fluid, raised already after one month, remained high at one year. The findings suggest progressive damage of the alveolar and interstitial tissues. Moreover, the increases in components of the extracellular matrix capable of building fibrotic networks are in agreement with the microscopical findings of fibrosis. Because only total cells, macrophages, and albumin concentrations correlated weakly with the silica contents of the lung, it is unlikely that the relation between quartz burden and the reaction in the lung is simple.

Animals↗

PubMed2004

Competitive plasma protein adsorption on modified polymer surfaces monitored by quartz crystal microbalance technique.

This paper describes the effects of photochemical modifications of polymer surfaces on the competitive adsorption of serum proteins and cell adhesion (hepatoma cell line HepG2, L929 fibroblasts and others). The UV modification of polystyrene, poly(methylmethacrylate) and polycarbonate alters the physico-chemical properties of these polymers in a way that allows the formation of micrometer scaled cellular patterns in vitro by controlling the composition and properties of the protein adsorbate. Using a quartz microbalance technique, capable to extract viscoelastic data in addition to the mass load of the polymer coated sensor, we have demonstrated the importance of the thickness and the viscosity of an albumin adsorbate for the observed cell adhesion in vitro. The quantity and viscosity of surface bound albumin on polystyrene, being a cell repellent material in its native state, is lowered when the surface is exposed to UV of lambda = 185 nm in air prior to the contact with albumin solutions or cell culture media. This promotes the deposition of cell adhesion proteins and explains the observed cell patterns. Apart from this special application the described quartz microbalance with dissipation monitoring provides a useful tool for general biocompatibility studies based on surface phenomena of biomaterials.

Adsorption↗

PubMed1983

Evidence for a dose-dependent inflammatory response to quartz in the rat lung and its significance in early changes in collagen metabolism.

The response of the rat lung to a range of doses of quartz at 50 and 100 days after its administration by intratracheal instillation has been assessed by bronchopulmonary lavage. The effects on the number of polymorphonuclear leukocytes (PMN), lymphocytes and macrophages are described. In addition the concentrations of soluble protein and hydroxyproline and the activities of lactate dehydrogenase, PZ peptidase and collagenase in lavage fluid supernatants were measured and an assessment of the hydroxyproline content of recovered cells was made. Finally PZ peptidase and collagenase were assayed in PMN-enriched cell fractions and in samples obtained from short-term culture of recovered macrophages. There was a dose-dependent increase in the recovery of all three cell types, and in the amounts of lactate dehydrogenase, protein and hydroxyproline in lavage fluids, which showed no signs of resolution over the 100-day period studied. Measurements of PZ peptidase and collagenase suggested that the PMN, not the macrophages, are the major source of these degradative enzymes. The relevance of these findings with regard to the importance of PMN in quartz-induced fibrosis is discussed.

Animals↗

PubMed2006

Rapid and simultaneous quantification of 4 urinary proteins by piezoelectric quartz crystal microbalance immunosensor array.

BACKGROUND: Urinary proteins are predictive and prognostic markers for diabetes nephropathy. Conventional methods for the quantification of urinary proteins, however, are time-consuming, and most require radioactive labeling. We designed a label-free piezoelectric quartz crystal microbalance (QCM) immunosensor array to simultaneously quantify 4 urinary proteins. METHODS: We constructed a 2 x 5 model piezoelectric immunosensor array fabricated with disposable quartz crystals for quantification of microalbumin, alpha1-microglobulin, beta2-microglobulin, and IgG in urine. We made calibration curves after immobilization of antibodies at an optimal concentration and then evaluated the performance characteristics of the immunosensor with a series of tests. In addition, we measured 124 urine samples with both QCM immunosensor array and immunonephelometry to assess the correlation between the 2 methods. RESULTS: With the QCM immunosensor array, we were able to quantify 4 urinary proteins within 15 min. This method had an analytical interval of 0.01-60 mg/L. The intraassay and interassay imprecisions (CVs) were <10%, and the relative recovery rates were 90.3%-109.1%. Nonspecificity of the immunosensor was insignificant (frequency shifts <20 Hz). ROC analyses indicated sensitivities were > or =95.8% and, specificities were > or =76.3%. Bland-Altman difference plots showed the immunosensor array to be highly comparable to immunonephelometry. CONCLUSIONS: The QCM system we designed has the advantages of being rapid, label free, and highly sensitive and thus can be a useful supplement to commercial assay methods in clinical chemistry.

Alpha-Globulins↗

PubMed2001

The quartz crystal microbalance as a novel means to study cell-substrate interactions in situ.

The quartz crystal microbalance (QCM) was first introduced as a mass sensor in gas phase and in vacuum. Since oscillator circuits capable of exciting shear vibrations of quartz resonators under liquid loading have been developed, the QCM became accepted as a new, powerful technique to follow adsorption processes at solid-liquid interfaces in chemical and biological research. Lately, the QCM technique has attracted considerable interest as a novel means to monitor cell-substrate interactions of mammalian cells in vitro. Because the establishment and modulation of cell-substrate contacts is important for many physiological processes, and potent techniques to measure these interactions noninvasively are rare, the present review highlights applications of the QCM technique in this field. The suitability of the QCM device to monitor attachment and spreading of mammalian cells in real time has been well established. The QCM response is dependent on the individual cell type that is examined. In order to identify the sources for these cell-type-specific results of QCM readings, and to understand the information content of the signal, attempts have been made to decompose the overall QCM response into subcellular contributions. The aforementioned subjects, together with a condensed introduction into the QCM technology, are included in this article.

Adsorption↗