Quantum chemical study of properties and reactivity of quartz dust. I. Electronic structure of alpha-quartz.
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Crystallography↗
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Studies on the effect of quartz, bentonite and coal dust mixtures on macrophages in vitro.
The effect of quartz, bentonite and coal dusts as well as the effect of the artificial mixture of these dusts on TTC reduction and extra-and intra-cellular lactate dehydrogenase activity in peritoneal rat macrophages was determined in vitro. The cell-membrane-damaging effect of quartz caused a significant extracellular release of lactate dehydrogenase. Bentonite caused no extracellular enzyme release, which leads us to believe that the biological effect of this dust is shown by decrease in intra-cellular lactate dehydrogenase activity. TTC reduction was inhibited equally by quartz and qentonite. In mixtures of quartz (60%)-bentonite (40%) dust the specific effect of quartz was inhibited by bentonite in vitro and also in vivo. We obtained the same results with coal-quartz-bentonite dust mixtures in vitro. Our experiments show that comparison of the biological effects of artificial dust mixtures and airborne dust samples is justified, and prove that performing various examinations simultaneously give fuller particulars on the probable biological effect of mineral dusts.
Animals↗
Quartz fibers as templates for biopolymers.
The polymerization of silica in water solution to form quartz fibers proceeds by a dehydration process, analogous to condensation polymerization in organic high-polymers, in which monomeric Si(OH)4 groups unite through Si--O--Si bonds with the elimination of H2O. The resulting fibers are structurally polar along the direction of elongation, are enantiomorphous, and generally show stereospecific twisting around the direction of elongation. In these regards the fibers are analogues of biopolymers such as RNA and DNA. Quartz also possesses specific adsorptive relations to a wide range of organic substances including monomer amino acids, short-chain polypeptides, and proteins. These involve hydrogen-bonding between (OH) or silanol groups on the surface of the quartz with active side-groups on the organic molecules, and in part are epitaxial through dimensional coincidences in the interface. Geochemical evidence indicates that quartz was deposited in the early Precambrian ocean either by direct crystallization from seawater or by recrystallization of amorphous silica. What is of interest is the possible role of quartz fibers as a template and co-polymer in the passage of biomonomers in the pre-biotic ocean to the long-chain biopolymers such as nucleic acids and proteins that are involved in life processes.
Adsorption↗
Asymmetric adsorption by quartz: a model for the prebiotic origin of optical activity.
One mechanism previously proposed for the abiotic accumulation of molecules of one chirality in nature is asymmetric adsorption on the chiral surfaces of optically active quartz crystals. Earlier literature in this field is reviewed, with the conclusion that previous investigations of this phenomenon, using optical rotation criteria, have afforded ambiguous results. We now have studied the adsorption of radioactive D- and L-alanine on powdered d- and l-quartz, using change in radioactivity level as a criterion for both gross and differential adsorption. d-Quartz preferentially adsorbed D-alanine from anhydrous dimethyl-formamide solution, and l-quartz L-alanine. The differential adsorption varied between 1.0 and 1.8%. The implications of these observations are discussed from the viewpoint of early chemical evolution and the origin of optically active organic compounds in nature.
Alanine↗
Determination of quartz on membrane filters by X-ray diffraction.
An X-ray diffraction method is described for the quantitative determination of quartz in dust samples. The analysis was done directly on a collecting cellulose ester membrane filter of the type used in an air sampler. Quantitation was achieved by the measurement of the quartz line intensities with a digital integrator and by the comparison of these values with those measured from calibration standards prepared on similar filters with water suspensions. The overall precision of the procedure was 8%. When the method was applied to foundry dusts, the accuracy of the quartz analysis was fou,d to be within 10% at the 1- to 10-mg level of total loading. The detection limit for quartz was below 0.1 mg.
Air Pollutants↗
In vitro action of quartz on alveolar macrophage lipid peroxides.
The in vitro effects of quartz particles on the lipid peroxide rate were measured on guinea pig pulmonary alveolar macrophages (PAMs). As controls, either PAMs alone or exposed to inert dust were used. The amount of lipid peroxide resulting after one-hour incubation was determined by means of the thiobarbituric acid test (TBA). The results showed that quartz induced a substantial increase of lipid peroxide in PAMs compared with both samples (dust-free or exposed to corundum). The influence of pretreatment of quartz by polyvinylpyridine-N-oxide (PVPNO) and by mineral water containing carbonate and chloride ions was also studied.
Adult↗
[Surface tension in rat lungs after quartz dust inhalation (author's transl)].
The influence of quartz dust (1000mg/m3) on surface tension in rat lungs was investigated. The exposure-times were 5, 15 and 30 hours. The animals were killed, 1, 7, 14, 28 and 90 days after quartz dust exposure and the surface tension was measured in a Wilhelmy balance. There was no significant difference between control animals and quartz dust animals in gammamax, gammamin and S. But there were significant differences in the same groups in hysteresis shape index and compressibility-coefficient.
Animals↗
[Experimental silicosis. I. Fibrogenic activity of quartz material used in the ceramic industry].
A high concentration of silica dust in the air many workstands in ceramic plants is a serious risk for the health of exposed workers. It can cause the development of silicosis. The aim of this paper is to evaluate a fibrogenic activity of dusts containing 98% crystalline silica. The ceramic masses have about 25% of Quartz. The samples of 2 lode quartz and 4 sand quartz originated from different mines in Poland were used for the experiment. Their physical properties were analysed by X-ray diffraction and SiO2 content was determined by colorimetry. Their biological aggresiveness was characterised by wet weight, hydroxyproline content, lipid level in the lungs and wet weight of mediastinal lymph nodes of rats which were intratracheally given of the dusts. The results show that the tested dusts have a moderated fibrogenic activity. At short time (3 months) after their administration the fibrogenic changes in lungs were different depending on the kind of dusts, but at the 6th month of the experiment they did not differ at all. The exposition of workers to silica dusts is a great occupational hazard.
Air Pollutants↗
[Water content in thin films of nucleic acid nitrogen bases. Ultramicroquantitative determination by means of a quartz resonator].
A method of quartz resonator is proposed for accurate micro- and ultramicroquantitative analysis of water in various biological systems. Sensitivity of this method may be about 10(-9) g. Some advantages and specific applications of quartz resonator are shown by "weighing" water rigidly bound to homogenous dry films of cytosine at great changes of their mass. It is suggested to use the quartz resonator with a specific sorbent applied to it as an efficient detector of small quantities of gases and microadmixtures of solved substances.
Chemical Phenomena↗
Ultrastructure of the lung in the rat following exposure to crocidolite asbestos and quartz.
Lung tissue from rats that had inhaled U.I.C.C. crocidolite asbestos or quartz particles showed thickening of the interstitial tissue and the presence of collagen fibres. Aggregates of macrophages in the alveolar spaces were a dominant feature of all the sections examined from asbestos exposed rats. According to the ultrastructural studies described here, all the macrophages were mature cells, indicating that the ingested crocidolite asbestos was non-toxic. Lung sections of rats exposed to quartz particles were significantly different. Single cells were found in the alveolar spaces and many macrophages showed a characteristic pattern of vacuole formation. Other cells contained intracellular membranous lamellated bodies, similar to those found in Type II pneumocytes. Cells containing lamellated bodies were also found in the interstitial tissue. These findings suggest that the two mineral dusts have quite different biological effects on the macrophage and that the development of pulmonary fibrosis may, to some extent, be caused by a different mechanism in each instance.
Animals↗
Atypical quartz dust-induced pneumoconiosis in SPF rats. Aspects of the role of the lymphatic system in the pathogenesis of silicosis.
Experimental exposure to quartz dust for 100 days (= 700 h) induces in SPF rats histologic changes of the lungs, which have such striking similarities with human cases of pulmonary alveolar proteinosis that they may represent an animal model of human disease. Conventional stock rats, the standard model of experimental silicosis research, react upon the same dosage of quartz dust by the formation or an increase in size of perivascular lymphatic sheaths, in which epitheloid cell granulomas can arise. In SPF rats such granulomas can only be developed in the sparse pre-existent lymphatic tissue, mostly in hilar lymph nodes. The reaction of SPF rats opens an interesting aspect on the significance of the phenomenon of lymphatic "drainage," as comparable reactions are only known in conventional rats following extreme dosage and in human pathology as so-called acute silicoproteinosis.
Animals↗
X-ray diffraction from micrograms of quartz on filters using a rotating anode.
X-ray diffraction data from samples of 20, 60 and 100 mug quartz on poly-vinyl chloride membrane filters have been collected using a rotating anode x-ray source. These data suggest that 17 mug of quartz or possibly less could be measured directly on 35 mm diameter filters without any type of pretreatment.
Dust↗
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↗
The effect of quartz and other non-coal dusts in coalworkers' pneumoconiosis. Part II. Lung autopsy study.
Preliminary pathological and mineralogical studies are reported on seventy-four sets of lungs from British coal miners who have been employed at the collieries included in the National Coal Boards's Pneumoconiosis Field Research. The degree of lung damage was considered in relation to the lung dust content and to the known dust exposures of the men concerned. Lungs were classified as having soft macules, fibrotic nodules or PMF. Those with soft macules had the lowest dust content but there was no significant difference between the dust contents of the lungs with fibrotic lesions and those with PMF. The percentage of non-coal minerals in the lung dust appeared to increase with the pathological classification from soft macules to PMF, and comparisons with the exposure data indicated a preferential retention of non-coal minerals, and especially of quartz, in the cases with the more severe lesions. Histological examination of the lesions showed the packing of dust was less close and the cellular response more vigorous with the lungs with the highest quartz content.
Aged↗
Effect of quartz dust on the lungs of mice.
Intratracheal inoculations of quartz dust (250 mg/kg body weight) of a particle size less than 5 mum were given in mice and pulmonary tissue reactions studied over a period of 210 days. Acute inflammatory reaction in the lung parenchyma was observed at early periods and later the aggregates of dust laden macrophages encountered around bronchi and blood vessels. Towards the termination of the experiment at 210 days the fibrotic reaction comprised chiefly of thick compactly arranged reticulin fibers with few collagen fibers which remained restricted to the peribronchial and perivascular areas. There was no silicotic nodule formation in the parenchyma of the lung. The atypical pulmonary tissue response to quartz dust in mice has been attributed to different tissue reactivity.
Animals↗
The asymmetric adsorption of alpha-aminopropionitrile on D-quartz.
alpha-Aminopropionitrile was adsorbed on the powdered D-quartz, recovered as N-trifluoro-acetylalanyl-(+)-secondarybutyl ester, and analyzed by means of gas chromatography. The asymmetric result supporting the preferential adsorption of L-antipode was obtained and its significance in chemical evolution has been discussed.
Adsorption↗
Dissolution of silicic acid from amosite and quartz dusts under physiological conditions.
The dissolution of silica from amosite dust in human serum and in Ringer buffer at 37 degrees C was found to be significantly higher than that from quartz. The significance of this finding in relation to their fibrogenic effects has been discussed.
Asbestos↗
[The effect of asbestos cement, UICC asbestos samples and quartz on the peritoneum of the mouse].
Aqueous suspensions of asbestos cement powder injected experimentally into the peritoneal cavity of mice act as a fibrogenic agent, as do chrysotile asbestos or chrysotile asbestos-containing soil samples. The fibrotic nodules caused by the dust resemble morphologically silicosis granulomas. In addition, asbestos cement has a characteristically strong cytotoxic effect during the first 2 weeks of the experiment. It is suggested that this is due to the chrysotile asbestos and/or the calcite component of the powder. Amosite and crocidolite, on the other hand, induce a diffuse peritoneal fibrosis with the appearance of numerous foreign body giant cells and asbestos bodies. Dust particles displaced to the regional lymph nodes are frequent in the animals treated with quartz, asbestos cement and asbestos-containing soil samples. A spindle cell type sarcoma arising from the visceral peritoneum is observed in animals injected with crocidolite or asbestos cement. In addition, dusts containing chrysotile asbestos induce considerable amyloidosis of the liver and spleen.
Amyloidosis↗