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Among the crystal forms of calcium carbonate, aragonite has needle-like shape. Although materials with needle-shaped crystals are associated with pulmonary toxicity, the toxic activity of aragonite is unclear. Therefore, proinflammatory potential of aragonite, neutralized aragonite and potassium titanate whisker was evaluated. The cellular effects of aragonite were weaker than those of potassium titanate whisker. Aragonite treatment induced the expression of chemokines in A549 cells and macrophages. Although aragonite exhibited proinflammatory effects in vitro, pulmonary inflammation was not observed in vivo after intratracheal administration of aragonite in mice. We did not observe the induction of inflammatory cytokine secretion or tissue lesion in the lungs of mice after administration of aragonite. Potassium titanate whisker treatment induced chemokine secretion in vitro. An increase in the number of neutrophils was observed in the mice lung tissue after administration of potassium titanate whisker. Aragonite and neutralized aragonite both induced an increase in the levels of intracellular calcium, but the levels were significantly higher in cells treated with aragonite than in cells treated with neutralized aragonite. These results suggested that intracellular calcium release mediates the cellular effects of aragonite. The toxicity of aragonite based on its needle-like structure was also not observed.

Calcium carbonate rock dust (RD) is used in mining to reduce the explosivity of aerosolized coal. During the dusting procedures, potential for human exposure occurs, raising health concerns. To improve RD aerosolization, several types of anti-caking surface treatments exist. The aim of the study was to evaluate cytotoxicity of four respirable RD samples: untreated/treated limestone (UL/TL), untreated/treated marble (UM/TM), and crystalline silica (SiO 2 ) as a positive control in A549 and THP-1 transformed human cell lines. Respirable fractions were generated and collected using FSP10 high flow-rate cyclone samplers. THP-1 cells were differentiated with phorbol-12-myristate-13-acetate (20 ng/ml, 48 h). Cells were exposed to seven different concentrations of RD and SiO 2 (0-0.2 mg/ml). RD caused a slight decrease in viability at 24 or 72 h post-exposure and were able to induce inflammatory cytokine production in A549 cells, however, with considerably less potency than SiO 2 . In THP-1 cells at 24 h, there was significant dose-dependent lactate dehydrogenase, inflammatory cytokine and chemokine release. Caspase-1 activity was increased in SiO 2 - and, on a lesser scale, in TM- exposed cells. To test if the increased toxicity of TM was uptake-related, THP-1 cells were pretreated with Cytochalasin D (CytD) or Bafilomycin A (BafA), followed by exposure to RD or SiO 2 for 6 h. CytD blocked the uptake and significantly decreased cytotoxicity of all particles, while BafA prevented caspase-1 activation but not cytotoxic effects of TM. Only TM was able to induce an inflammatory response in THP-1 cells, however it was much less pronounced compared to silica., (Published by Elsevier Inc.)

Calcium carbonate nanomaterials (nano-CaCO 3 ) are widely used in both manufacturing and consumer products, but their potential health hazards remain unclear. The objective of this study was to survey workplace exposure levels and health effects of workers exposed to nano-CaCO 3 . Personal and area sampling, as well as real-time and dust monitoring, were performed to characterize mass exposure, particle size distribution, and particle number exposure. A total of 56 workers (28 exposed workers and 28 unexposed controls) were studied in a cross-sectional study. They completed physical examinations, spirometry, and digital radiography. The results showed that the gravimetric nano-CaCO 3 concentration was 5.264 ± 6.987 mg/m 3 (0.037-22.192 mg/m 3 ) at the workplace, and 3.577 ± 2.065 mg/m 3 (2.042-8.161 mg/m 3 ) in the breathing zone of the exposed workers. The particle number concentrations ranged from 8193 to 39 621 particles/cm 3 with a size range of 30-150 nm. The process of packing had the highest gravimetric and particle number concentrations. The particle number concentration positively correlated with gravimetric concentrations of nano-CaCO 3 . The levels of hemoglobin, creatine phosphokinase (CK), lactate dehydrogenase, and high-density lipoprotein cholesterol (HDL-C) in the nano-CaCO 3 exposure group increased significantly, but the white blood cell count (WBC), Complement 3 (C3), total protein (TP), uric acid, and creatinine (CREA) all decreased significantly. The prevalence rate of pulmonary hypofunction was significantly higher (p = 0.037), and the levels of vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, peak expiratory flow and forced expiratory flow 25% (FEF 25%), FEF 25-75% were negatively correlated with gravimetric concentrations of nano-CaCO 3 (p < 0.05). Logistic analysis showed that nano-CaCO 3 exposure level was associated with pulmonary hypofunction (p = 0.005). Meanwhile, a dose-effect relationship was found between the accumulated gravimetric concentrations of nano-CaCO 3 and the prevalence rate of pulmonary hypofunction (p = 0.048). In conclusion, long-term and high-level nano-CaCO 3 exposure can induce pulmonary hypofunction in workers. Thus, lung function examination is suggested for occupational populations with nano-CaCO 3 exposure. Furthermore, future health protection efforts should focus on senior workers with accumulation effects of nano-CaCO 3 exposure.

Chalk teaching is widely used in the world due to low cost, especially in some developing countries. During teaching with chalks, a large amount of fine chalk dust is produced. Although exposure to chalk dust is associated with respiratory diseases, the mechanism underlying the correlation between chalk dust exposure and adverse effects has not fully been elucidated. In this study, inflammation and its signal pathway in rat lungs exposed to fine chalk dust were examined through histopathology analyses; pro-inflammatory gene transcription; and protein levels measured by HE staining, RT-PCR, and western blot analysis. The results demonstrated that fine chalk dust increased neutrophils and up-regulated inflammatory gene mRNA levels (TNF-α, IL-6, TGF-β1, iNOS, and ICAM-1), and oxidative stress marker (HO-1) level, leading to the increase of inflammatory cell infiltration and inflammatory injury on the lungs. These inflammation responses were mediated, at least in part, via p38 and extracellular regulated proteinase (ERK) mitogen-activated protein kinase (MAPK) signaling mechanisms. In contrast, N-acetyl-L-cysteine (NAC) supplement significantly ameliorated these changes in inflammatory responses. Our results support the hypothesis that fine chalk dust can damage rat lungs and the NAC supplement may attenuate fine chalk dust-associated lung inflammation.

Pterospermum kingtungense C.Y.Wu ex Hsue is a typical tree species living in the relatively adverse limestone habitat. Due to its excellent wood quality and big size, it is an important timber resource which caused its endangered. We firstly provide the data resources by reporting an annotated transcriptome assembly. 203 million unique Illumina RNA-seq reads were produced with totally 50,333 transcripts, among which 48,778 transcripts were annotated. By a global comparison of homology between P. kingtungense and cacao, we identified 9,507 single copy orthologues and 990 P. kingtungense specific genes. GO enrichment analyses indicate that P. kingtungense specific genes are enriched in defense response, implying potential adaptation to limestone environment. As to cell compartment, the genes are enriched in thylakoid component. Consistently, KEGG enrichment indicates that genes are enriched in photosynthesis. In addition, we identified two genes under positive selection in P. kingtungense species. These results suggest that P. kingtungense have strong photosynthetic capacity, which related to vegetation growth. Our work provides the genomic resources of a limestone specific tree with economic importance to local society and suggests possible mechanism on its characteristics on the limestone adaption and excellent wood properties, which will be important for its conservation and sustainable utilization.

Pulmonary alveolar proteinosis (PAP) is a rarely seen disease of the alveoli, characterized by accumulation of proteinous material, which stains positive with periodic acid Schiff, in the alveoli. Secondary PAP may develop as a result of occupational exposure to materials such as silica and indium. In the paper, together with a review of the relevant literature, we present an uncommon case of a 47-year old male, marble worker who was diagnosed with PAP associated with a 12-year history of exposure to marble dust. Int J Occup Med Environ Health 2016;29(5):871-876., (This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.)

Background: Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern about the contribution of calcium supplementation to cardiovascular risk. A proposed mechanism is through the acceleration of coronary artery calcification. Determining causality between calcium intake and coronary artery calcification has been hindered by a lack of sensitive methodology to monitor early vascular calcium accumulation. The primary study aim was to assess the impact of high calcium intake on coronary artery calcification using innovative calcium tracer kinetic modeling in Ossabaw swine with diet-induced metabolic syndrome. Secondary end points (in vitro wire myography, histopathology, intravascular ultrasound) assessed coronary disease., Methods and Results: Pigs (n=24; aged ≈15 months) were fed an atherogenic diet with adequate calcium (0.33% by weight) or high calcium (1.90% from calcium carbonate or dairy) for 6 months. Following 5 months of feeding, all pigs were dosed intravenously with (41)Ca, a rare isotope that can be measured in serum and tissues at a sensitivity of 10(-18) mol/L by accelerator mass spectrometry. Kinetic modeling evaluated early coronary artery calcification using (41)Ca values measured in serial blood samples (collected over 27 days) and coronary artery samples obtained at sacrifice. Serum disappearance of (41)Ca and total coronary artery (41)Ca accumulation did not differ among groups. Secondary end points demonstrated no treatment differences in coronary artery disease or function., Conclusion: There was no detectable effect of high calcium diets (from dairy or calcium carbonate) on coronary artery calcium deposition in metabolic syndrome swine., (© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

The main aim of the present study was to examine in vitro responses of rat alveolar macrophages (AMs) exposed to coarse chalk dust particles (particulate matter in the size range 2.5-10 μm, PM(coarse)) by respiratory burst and oxidative stress. Chalk PM(coarse)-induced respiratory burst in AMs was measured by using a luminol-dependent chemiluminescence (CL) method. Also, the cell viability; lactate dehydrogenase (LDH) release; levels of cellular superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), malondialdehyde (MDA), and acid phosphatase (ACP); plasma membrane ATPase; and extracellular nitric oxide (NO) level were determined 4 h following the treatment with the different dosages of chalk PM(coarse). The results showed that chalk PM(coarse) initiated the respiratory burst of AMs as indicated by strong CL, which was inhibited by diphenyleneiodonium chloride and L-N-nitro-L-arginine methyl ester hydrochloride. It suggested that chalk PM(coarse) induced the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in AMs. This hypothesis was confirmed by the fact that chalk PM(coarse) resulted in a significant decrease of intracellular SOD, GSH, ACP, and ATPase levels and a notable increase of intracellular CAT, MDA content, and extracellular NO level, consequently leading to a decrease of the cell viability and a increase of LDH release. It was concluded that AMs exposed to chalk PM(coarse) can suffer from cytotoxicity which may be mediated by generation of excessive ROS/RNS. Graphical Abstract The possible mechanism of coarse chalk particles-induced adverse effects in AMs.

Dolomite is a natural mineral of great industrial and commercial importance. With the advent of nanotechnology, natural minerals including dolomite in the form of nanoparticles (NPs) are being utilized in various applications to improve the quality of products. However, safety or toxicity information of dolomite NPs is largely lacking. This study evaluated the cytotoxicity of dolomite NPs in two widely used in vitro cell culture models: human airway epithelial (HEp2) and human liver (HepG2) cells. Concentration-dependent decreased cell viability and damaged cell membrane integrity revealed the cytotoxicity of dolomite NPs. We further observed that dolomite NPs induce oxidative stress in a concentration-dependent manner, as indicated by depletion of glutathione and induction of reactive oxygen species (ROS) and lipid peroxidation. Quantitative real-time PCR data demonstrated that the mRNA level of tumor suppressor gene p53 and apoptotic genes (bax, CASP3 and CASP9) were up-regulated whereas the anti-apoptotic gene bcl-2 was down-regulated in HEp2 and HepG2 cells exposed to dolomite NPs. Moreover, the activity of apoptotic enzymes (caspase-3 and caspase-9) was also higher in both kinds of cells treated with dolomite NPs. It is also worth mentioning that HEp2 cells seem to be marginally more susceptible to dolomite NPs exposure than HepG2 cells. Cytotoxicity induced by dolomite NPs was efficiently prevented by N-acetyl cysteine treatment, which suggests that oxidative stress is primarily responsible for the cytotoxicity of dolomite NPs in both HEp2 and HepG2 cells. Toxicity mechanisms of dolomite NPs warrant further investigations at the in vivo level., (Copyright © 2015 John Wiley & Sons, Ltd.)

Objective: To describe the prehospital management and safety of search and rescue (SAR) teams involved in a large-scale rockfall disaster and monitor the acute and chronic health effects on personnel with severe dolomitic dust exposure., Methods: SAR personnel underwent on-site medical screening and lung function testing 3 months and 3 years after the event., Results: The emergency dispatch center was responsible for central coordination of resources. One hundred fifty SAR members from multidisciplinary air- and ground-based teams as well as geotechnical experts were dispatched to a provisionary operation center. Acute exposure to dolomite dust with detectable silicon and magnesium concentrations was not associated with (sub)acute or chronic sequelae or a clinically significant impairment in lung function in exposed personnel., Conclusions: The risk for personnel involved in mountain SAR operations is rarely reported and not easily investigated or quantified. This case exemplifies the importance of a multiskilled team and additional considerations for prehospital management during natural hazard events. Safety plans should include compulsory protective measures and medical monitoring of personnel., (Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)

The aim of the study is to investigate chemical compositions of fine chalk dust particles (chalk PM2.5) and examine their adverse effects on alveolar macrophages (AMs) in vitro. Morphologies and element concentrations of individual chalk particles were analyzed by using the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). The oxidative response of AMs and the potential to generate nitric oxide (NO) by luminol-dependent chemiluminescence (CL) and nitrate reductase method were assessed 4h following the treatment of AMs with differing dosages of fine chalk particles, respectively. Oxidative stress and cytotoxicity elicited by chalk PM2.5 were also examined. The results showed that fine chalk particles were mainly composed of gypsum, calcite, dolomite and a little amount of organic adhesives. Exposure to chalk PM2.5 at 100 μg mL(-1) or 300 μg mL(-1) significantly increased intracellular catalase, malondialdehyde, and NO levels and decreased superoxide dismutase level in AMs, leading to leakage of lactate dehydrogenase (LDH) and reduction of the cell viability. Furthermore, luminol-dependent CL from respiratory burst in AMs was enhanced. It was suggested that chalk PM2.5 could make oxidative damages on AMs and result in cytotoxicity, being likely attributed to excessive reactive oxygen species or reactive nitrogen species induced by mixture of fine gypsum and calcite/dolomite particles., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In our previous studies of nanocalcium carbonate, in which we performed physicochemical analysis, genotoxicity, acute single-dose and repeated-dose 14-day oral toxicity testings in Sprague-Dawley (SD) rats, nanocalcium carbonate did not show a difference in toxicity compared to vehicle control. Here, we provide the first report of a repeated-dose 90-day oral toxicity test of nanocalcium carbonate in Sprague-Dawley rats, with physicochemical comparison of micro and nanocalcium carbonate. We find that the two particles differ in size, hydrodynamic size, and specific surface area, with no differences in components, crystalline structure and radical production. In terms of ionization ability, nanocalcium carbonate was slightly more ionized within 1% than microcalcium carbonate at pH 5 and pH 7. In the repeated-dose 90-day oral toxicity test of nanocalcium carbonate, there was no significant toxicity, and similar blood concentrations of Ca(2+) compared to the vehicle control group. Based on our results, although nanocalcium carbonate has different physicochemical properties, nanocalcium carbonate does not differ from microcalcium carbonate in terms of toxicity. Based on the results, we suggest that the no-observed-adverse-effect level (NOAEL) of nanocalcium carbonate is 1000 mg kg(-1) day(-1) in SD rats according to the maximum dose (OECD guideline 408). However, the NOAEL might be higher than 1000 mg kg(-1) day(-1) because there were no adverse effects revealed by consistent pathological findings or biochemical parameter changes. To justify a safe concentration of nanocalcium carbonate, which is a low toxicity chemical, more data is required on dose levels above 1000 mg kg(-1). Our findings may be useful for creating safety guidelines for the use nanocalcium carbonate.

The purposes of this article were to investigate the influences of synthesis strategy on the CaCO(3) crystals on the cellulose substrate. In this study, CaCO(3) crystals were synthesized using cellulose as matrix by the microwave-assisted method and ultrasound agitation method, respectively. The CaCO(3) crystals on the cellulose substrate were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Experimental results demonstrated that the synthesis strategy had a dramatically influences on the phase, microstructure, morphology, thermal stability, and biological activity of the CaCO(3) crystals. The pure phase of vaterite spheres with the diameter of about 320-600nm were obtained by ultrasound agitation method, meanwhile, the mixed phases of calcite and vaterite with the diameter of about 0.82-1.24μm were observed by microwave-assisted method. In view of experimental results, one can conclude that the ultrasound agitation method do more favors to the synthesis of CaCO(3) crystals with uniform morphology and size, compared with microwave-assisted method. Furthermore, cytotoxicity experiments indicated that the CaCO(3) crystals on the cellulose substrate had good biocompatibility and could be a candidate for the biomedical applications., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Dolomite is a natural mineral of great industrial importance and used worldwide, thus millions of workers are at risk of occupational exposure. Its toxicity is however, meagerly documented. In the present investigation, a dolomite powder obtained from its milling unit was analyzed by some standard methods namely, optical microscopy, transmission electron microscopy and dynamic light scattering. Results showed that dolomite powder contained particles of different shapes and size both microparticles (MPs) and nanoparticles (NPs), suggesting potential occupational exposure of these particles. An attempt was therefore, made to investigate dolomite toxicity in a particle size-dependent manner in human lung epithelial cells A(549). The comparative toxicity evaluation of MPs and NPs was carried out by assessing their effects on cell viability, membrane damage, glutathione, reactive oxygen species (ROS), lipid peroxidation (LPO), micronucleus (MN) and proinflammatory cytokines, namely tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). These markers of cytotoxicity, genotoxicity and inflammation were assayed in cells exposed to MPs and NPs in a dose-and time-dependent manner. Invariably, their toxic effects were dose-and time-dependent while NPs in general were significantly more toxic. Notably, NPs caused oxidative stress, genotoxicity and inflammatory responses, as seen by significant induction of ROS, LPO, MN, TNF-α, IL-1β and IL-6. Thus, the study tends to suggest that separate health safety standards would be required for micrometer and nanometer scale particles of dolomite., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Unlabelled: Outdoor particulate matter (PM(10)) is associated with detrimental health effects. However, individual PM(10) exposure occurs mostly indoors. We therefore compared the toxic effects of classroom, outdoor, and residential PM(10). Indoor and outdoor PM(10) was collected from six schools in Munich during teaching hours and in six homes. Particles were analyzed by scanning electron microscopy and X-ray spectroscopy (EDX). Toxicity was evaluated in human primary keratinocytes, lung epithelial cells and after metabolic activation by several human cytochromes P450. We found that PM(10) concentrations during teaching hours were 5.6-times higher than outdoors (117 ± 48 μg/m(3) vs. 21 ± 15 μg/m(3), P < 0.001). Compared to outdoors, indoor PM contained more silicate (36% of particle number), organic (29%, probably originating from human skin), and Ca-carbonate particles (12%, probably originating from paper). Outdoor PM contained more Ca-sulfate particles (38%). Indoor PM at 6 μg/cm(2) (10 μg/ml) caused toxicity in keratinocytes and in cells expressing CYP2B6 and CYP3A4. Toxicity by CYP2B6 was abolished with the reactive oxygen species scavenger N-acetylcysteine. We concluded that outdoor PM(10) and indoor PM(10) from homes were devoid of toxicity. Indoor PM(10) was elevated, chemically different and toxicologically more active than outdoor PM(10). Whether the effects translate into a significant health risk needs to be determined. Until then, we suggest better ventilation as a sensible option., Practical Implications: Indoor air PM(10) on an equal weight base is toxicologically more active than outdoor PM(10). In addition, indoor PM(10) concentrations are about six times higher than outdoor air. Thus, ventilation of classrooms with outdoor air will improve air quality and is likely to provide a health benefit. It is also easier than cleaning PM(10) from indoor air, which has proven to be tedious., (© 2011 John Wiley & Sons A/S.)

Marble workers are occupationally exposed to intense environmental marble dust in their workplace. We aimed to investigate the effect of occupational marble dust exposure on nasal mucociliary transport rate (NMTR). Seventeen marble workers and 18 healthy controls were studied. In all subjects, NMTRs were measured by (99m)Tc-MAA rhinoscintigraphy. NMTRs of workers and control groups were compared by statistically. Mean NMTR was found as 9 ± 1.8 mm/min in marble workers whereas mean NMTR of healthy controls was 9.6 ± 2.2 mm/min. There was no statistically significant difference between NMTRs of workers and control groups (p > 0.05). This study has shown that occupationally exposured marble dusts may not cause functional impairment on NMTR in marble workshop workers.

Six limestone samples were picked from three different points at the Obajana and Mfamosing limestone deposits. The limestone samples were subjected to elemental analysis by Proton-Induced X-Ray Emission (PIXE) analysis. The samples were irradiated by a 4mm diameter beam of protons with energy of 2.5 MeV and beam current of 0.2nA for 0.9 ms. The analysis was carried out with the 1.7MV Tandem accelerator at the Centre for Energy Research and Development (CERD), Ile-Ife, Osun State, Nigeria. The NIST geology standard NIST 278 was analysed for quality assurance. The elemental composition and concentration of 14 elements were determined in the two locations. Ten elements were found at the Obajana deposit while 13 elements were found at the Mfamosing deposits. The elements: Mg, Al, Ca and Mn do not differ much at both deposits while others differ. The major elements (Ca, Fe, Al, Si and K) present in the limestones were also found in airborne particulate matter studied by earlier researchers. These observations suggest that all particulate emissions and wastes from the Limestone deposit should be closely monitored to reduce their cumulative effects on both health and the environment., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The risk of occupational exposure to dolomite, an important mineral exists both in organized as well as unorganized sectors. Toxicological profiles of bulk dolomite are meagerly known in general and its nanotoxicity in particular. Effects of micro- and nano particles on cell viability, LDH leakage and markers of oxidative stress were observed. The study indicated that cytotoxicity of dolomite nanoparticles is significantly higher than the microparticles. The study thus suggests for the prescription of exposure limit for nanodolomite in the best interest of health of workers at risk of exposure under mining, milling and industrial environment.

Limestone processing is a global industry, but few studies have assessed respiratory health among limestone workers. At a limestone factory in Zambia, the authors studied 70 high-exposed workers from the production department, 40 medium-exposed from engineering, and 30 low-exposed from administration. A modified British Medical Research Council respiratory questionnaire was used for recording chronic respiratory symptoms. The prevalence of symptoms was highest among the production workers. After adjusting for age, smoking, previous jobs, and past respiratory diseases, the production workers still had a significantly increased relative risk for cough day and night, cough 4 to 6 times daily in a month, and cough with sputum. The results indicate that exposure to limestone dust is associated with increased prevalence of respiratory symptoms. Until newer technology is installed, proper use of personal protective equipments should be emphasized., (Copyright © 2011 Taylor & Francis Group, LLC)

Objective: The purpose of this article is to describe the high-resolution CT (HRCT) features of uncommon occupational lung diseases., Conclusion: HRCT plays an increasing role in the evaluation of occupational lung diseases. We present several cases of unusual occupational lung diseases and their HRCT findings. The diseases studied were siderosis, talcosis, berylliosis, calcicosis, hypersensitivity pneumonitis (due to wheat flour and isocyanates), and Ardystil syndrome. The characteristic HRCT findings together with clinical features and related occupational history improve the diagnostic accuracy of these diseases.

Exposure to cement dust, a specifically alkaline and irritant dust, is one of the most common occupational dust exposures worldwide. Although several adverse respiratory health effects have been associated with cement dust exposure, the evidence is not conclusive. In the current study, cytotoxic and pro-inflammatory effects as well as oxidative stress elicited by a number of cement dusts, including a limestone and cement clinker sample, were tested using the NR8383 rat alveolar macrophage cell line and primary rat alveolar macrophages. DQ12 quartz and TiO(2) were included as positive and negative controls, respectively. Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay and the lactate dehydrogenase assay, oxidative stress was determined by measurement of the depletion of total cellular glutathione, and electron spin resonance was applied to determine reactive oxygen species (ROS) generation. The release of the cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1 beta (IL-1 beta), and macrophage inflammatory protein-2 (MIP-2) was determined by enzyme-linked immunosorbent assay. None of the dust samples were found to cause toxicity to the macrophages or notable glutathione depletion when compared to DQ12. The cement samples also failed to activate macrophages for the generation of ROS and the production of inflammatory cytokines IL-1 beta and MIP-2. In contrast, however, most of the cement dusts were found to activate macrophage TNFalpha production, and this was significantly associated with their content of CaO. Further research is needed to determine the relevance of these in vitro observations for occupational cement dust exposure settings.

The potential of oral exposure to dolomite, a natural product that contains calcium and magnesium, to initiate teratogenesis was analyzed in Wistar rats. Animals received dolomite oral dosages of 500 and 1500mg/kg during the period of gestation from day 6-15 post conceptionem (p.c.). Maternal, embryo and fetal toxicity were evaluated. Dolomite exposure did not produce maternal toxicity assessed by clinical observations, body weight gain, hematology parameters and relative organs weight. Signs of embryo-fetal toxicity were not observed. Skeletal malformations and visceral variations were similar in control and dolomite-treated groups. On the other hand, slight increase was observed in fetal body weight in the dolomite-treated group. Treatment with dolomite resulted in significantly decreased incidences of unossified xiphisternum, incomplete ossification of xiphisternum and sternebrae. These effects could be caused by a beneficial influence of calcium and magnesium salts present in dolomite on ossification process. In conclusion, in this study we found that the oral exposure to rats of up to 1500mg/kg of dolomite during organogenesis did not induce significant maternal and embryo-fetal toxicity.

The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cement set and hardened within 2h at 37 degrees C in an atmosphere saturated with water and the final composition of the cement consisted mostly of aragonite. The hardened cement was microporous and showed poor mechanical properties. Cytotoxicity tests revealed excellent cytocompatibility of calcium carbonate cement compositions. Calcium carbonates with a higher solubility than the apatite formed for most of the marketed calcium phosphate cements might be of interest to increase biomedical cement resorption rates and to favour its replacement by bone tissue.

Although quarrying is often cited as a potential threat to wetland systems, there is a lack of relevant, quantitative case studies in the literature. The impact of pumped groundwater discharged from a quarry into a wetland area was assessed relative to reference conditions in an adjacent fen wetland that receives only natural runoff. Analysis of vegetation patterns at the quarry wetland site, using Detrended Correspondence Analysis and the species indicator values of Ellenberg, revealed a clear disparity between community transitions in the quarry wetland and the reference site. Limited establishment of moisture-sensitive taxa, the preferential proliferation of robust wetland species and an overall shift towards lower species diversity in the quarry wetland were explicable primarily by the physico-chemical environment created by quarry dewatering. This encompassed high pH (up to 12.8), sediment-rich effluent creating a nutrient-poor substrate with poor moisture retention in the quarry wetland, and large fluctuations in water levels.

In the present study, a hypothesis was tested that the addition of calcite into the Pennsylvania coals may reduce levels of bioavailable iron (BAI), an important component in the mixed coal dust that may contribute to coal workers' lung diseases. Predetermined proportions of calcite (0, 1, 2, 5, 10% w/w) were added into three PA coals. After suspending the mixtures in an aqueous phosphate solution (10 mM, pH 4.5), which mimics the phagolysosomal conditions of the cells, levels of pH as well as calcium ions (Ca2+) in the coals were increased in a calcite concentration-dependent manner. In contrast, levels of BAI (both Fe2+ and Fe3+) were decreased. The inhibitory effects of calcite on the bioavailability of iron in human lung epithelial A549 cells and primary rat alveolar macrophages (AMs) were also examined. It was found that levels of low-molecular-weight (LMW) iron were significantly decreased in both A549 cells and AMs treated with the 10% calcite-PA coal mixture compared to those treated with the PA coal alone, while calcite itself had no effect on intracellular LMW iron. Calcite also showed a significant inhibitory effect on PA coal-induced ferritin synthesis in A549 cells. Reverse-transcription polymerase chain reaction (RT-PCR) studies revealed that the iron-containing PA coal downregulated levels of transferrin receptor (TfR) mRNA in A549 cells, which was partially restored by the addition of calcite. Our results indicate that calcite can inhibit the bioavailability of iron in the iron-containing PA coals.

The two-dimensional distribution of flow patterns and their dynamic change due to microbial activity were investigated in naturally fractured chalk cores. Long-term biodegradation experiments were conducted in two cores ( approximately 20 cm diameter, 31 and 44 cm long), intersected by a natural fracture. 2,4,6-tribromophenol (TBP) was used as a model contaminant and as the sole carbon source for aerobic microbial activity. The transmissivity of the fractures was continuously reduced due to biomass accumulation in the fracture concurrent with TBP biodegradation. From multi-tracer experiments conducted prior to and following the microbial activity, it was found that biomass accumulation causes redistribution of the preferential flow channels. Zones of slow flow near the fracture inlet were clogged, thus further diverting the flow through zones of fast flow, which were also partially clogged. Quantitative evaluation of biodegradation and bacterial counts supported the results of the multi-tracer tests, indicating that most of the bacterial activity occurs close to the inlet. The changing flow patterns, which control the nutrient supply, resulted in variations in the concentrations of the chemical constituents (TBP, bromide and oxygen), used as indicators of biodegradation.

We compared the urothelial injury to the bladder caused by four agents capable of dissolving calcium salts. The solutions were administrated in an antegrade way through left ureterostomies in 54 rabbits for periods of 24, 48 and 72 h. The bladders were then removed and three routine histological sections were made for each. The following six solutions were used: physiological sodium chloride solution (Phys), artificial urine (Art), 0.03 M disodium EDTA buffered to pH 8.5 with triethanolamine (EDTA), 10% Renacidin (R), test solution 2 (S2, using D-gluconic acid-lactone and other compounds that differ from R in terms of ingredients or quantity), and test solution 1 (S1, using D-gluconic-acid instead of D-gluconic acid-lactone in S2 but keeping the other ingredients the same) for irrigation. At 24 h there was no observable urothelial damage caused by perfusion with Phys or Art; solutions R, S1 and S2 caused approximately the same level of injury to the rabbit bladder mucosa; however, irrigation with disodium-EDTA caused more serious urothelial injury than R, S1 and S2 (P<0.05, chi2-test) and may be unacceptable. The damage to bladder tissues treated with S1 and S2 was less than that caused by R, but this was not significant (P>0.05, chi2-test). Following a prolonged irrigation time, all of these solutions cause further urothelial damage, but EDTA caused the most, followed by R, S1, S2, Phys or Art, respectively, at 48 and 72 h. In view of the better solubility effect of solutions S1 and S2 compared with R, it might be justified in accepting the more pronounced urothelial irritation caused these solutions, but in order to enhance their effectiveness and reduce urothelial injury further study will be needed.

The aim of this study was to evaluate the in vitro cytotoxicity of biomaterials; Hydroxyapatite (HA), Natural coral (NC) and Polyhydroxybutarate (PHB). Three different materials used in this study; HA (Ca10(PO4)6(OH)2), NC (CaCO3) and PHB (Polymer) were locally produced by the groups of researcher from Universiti Sains Malaysia. The materials were separately extracted in the complete culture medium (100mg/ml) for 72h and introduced to the osteoblast cells CRL-1543. The viability of osteoblast CRL-1543 cultivated with these extraction materials after 72h incubation period was compared to negative control with neutral red assay by using spectrophotometer at 540nm. The results showed the non-cytotoxicity of the materials. After 72h of incubation period, HA showed 123% viable cells, NC was 99.43% and PHB was 176.75%. In this study, cytotoxicity test dealt mainly with the substances that leached out from the biomaterial. The results obtained showed that the materials were not toxic and also promoted cells growth in the sense of biofunctionality.

Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.

In this report, we have identified oxalic acid as an important metabolite elaborated in the response of wood-rotting fungi to toxic metal stress. The formation of oxalate crystals by white rot fungi (Bjerkandera fumosa, Phlebia radiata and Trametes versicolor) and the brown rot fungus Fomitopsis pinicola, grown on media containing high levels of toxic metal ions has been visualized using scanning electron microscopy (SEM) with energy-dispersive X-ray micro-analysis (EDXA) and HPLC. There were no significant differences between the growth of controls (metal-free) and on the 0.5% CaCO(3), Co(3)(PO(4))(2) or Zn(3)(PO(4))(2)-amended plates. ZnO inhibited the growth of all strains. Crystals were not detected in Zn(3)(PO(4))(2)-amended plates. The four examined strains displayed the formation of crystals on ZnO, Co(3)(PO(4))(2) and CaCO(3)-amended plates.

The toxicity of many chemicals depends on the physical conditions of the test environment, and any change or adjustment made to the tests can alter the results. Therefore it is important to establish the sensitivity of the test organism over a range of test conditions to determine when it is necessary to make adjustment and to what extent. In this study, we established the tolerance range of the nematode Caenorhabditis elegans for pH, salinity and hardness using 24- (without food source) and 96-h (with food source) aquatic toxicity tests. The tests were performed in two media: K-medium and moderately hard reconstituted water (MHRW). C.elegans has high tolerance under these test conditions. In K-medium worms survived a pH range of 3.1 to 11.9 for 24 h and 3.2 to 11.8 for 96 h without significant (p > 0.05) lethality. In MHRW the pH range was 3. 4 to 11.9 for 24 h and 3.4 to 11.7 for 96 h. Salinity tolerance tests were approximated with NaCl and KCl individually. Up to 15.46 g/L NaCl and 11.51 g/L KCl were tolerated by C. elegans in K-medium without significant lethality (p> 0.05). In MHRW higher salt concentrations were tolerated; about 20.5 g/L NaCl and 18.85 g/L KCl did not show any adverse effect compared to control. Hardness tolerance was tested by adding NaHCO3. The nematode could tolerate 0. 236 to 0.246 g/L of NaHCO3. The high tolerance of C. elegans to these test conditions (pH, salinity, and hardness) allows more versatility than other organisms commonly used in aquatic toxicity tests. It also allows the monitoring of effluents and receiving waters from freshwater or estuarine sources without dilution or adjustment.

This study was designed to evaluate the developmental effects of moderate dietary calcium increases in rats fed nutritionally adequate diets. Female Charles River CD/VAF Plus rats were given 0.50 (control), 0.75, 1.00 or 1.25% dietary calcium as calcium carbonate in AIN-76A diets for 6 wk before mating, during mating and for 20 days of gestation. On gestation day 20, the animals were killed and caesarean sections were performed. Both the non-pregnant and pregnant rats in the 0.75, 1.00 and 1.25% groups ate slightly more than did the control group during most of the intervals measured, but not all the increases were statistically significant. There was no consistent pattern of increase or decrease in weight gain. No dose-related changes were found in maternal clinical findings, the average number of implantations, resorptions and viable foetuses, or foetal length or weight. Under the conditions of the study, there were no statistically significant increases as compared with the control group in the litter incidence regarding specific external, visceral or skeletal variations of the foetuses. Dietary calcium was neither foetotoxic nor teratogenic at the concentrations used.

Sodium saccharin and sodium ascorbate are known to promote urinary bladder carcinogenesis in rats following initiation with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) or N-butyl-N-(4-hydroxybutyl) nitrosamine. Sodium salts of other organic acids have also been shown to be bladder tumor promoters. In addition, these substances increase urothelial proliferation in short term assays in rats when fed at high doses. When they have been tested, the acid forms of these salts are without either promoting or cell proliferative inducing activity. The following experiment was designed to compare the tumor promoting activity of various forms of saccharin and to evaluate the role in promotion of urinary sodium, calcium, and pH as well as other factors. Twenty groups of 40 male F344 rats, 5 weeks of age, were fed either FANFT or control diet during a 6-week initiation phase followed by feeding of a test compound for 72 weeks in the second phase. The chemicals were administered to the first 18 groups in Agway Prolab 3200 diet and the last 2 groups were fed NIH-07 diet. The treatments were as follows: (a) FANFT----5% sodium saccharin (NaS); (b) FANFT----3% NaS; (c) FANFT----5.2% calcium saccharin (CaS); (d) FANFT----3.12% CaS; (e) FANFT----4.21% acid saccharin (S); (f) FANFT----2.53% S; (g) FANFT----5% sodium ascorbate; (h) FANFT----4.44% ascorbic acid; (i) FANFT----5% NaS plus 1.15% CaCO3; (j) FANFT----5.2% CaS plus 1.34% NaCl; (k) FANFT----5% NaS plus 1.23% NH4Cl; (l) FANFT----1.15% CaCO3; (m) FANFT----1.34% NaCl; (n) FANFT----control; (o) control----5% NaS; (p) control----5.2% CaS; (q) control----4.21% S; (r) Control----control; (s) FANFT----5% NaS (NIH-07 diet); (t) FANFT----control (NIH-07 diet). NaS, CaS and S without prior FANFT administration were without tumorigenic activity. NaS was found to have tumor promoting activity, showing a positive response at the 5 and 3% dose levels, with significantly greater activity at the higher dose. CaS had slight tumor promoting activity but without a dose response, and S showed no tumor promoting activity. In addition, NaCl showed weak tumor promoting activity, but CaCO3 was without activity. NH4Cl completely inhibited the tumor promoting activity of NaS when concurrently administered with it. NaCl administered with CaS or CaCO3 administered with NaS showed activity similar to that of NaS. Sodium ascorbate was also shown to have tumor promoting activity, with slightly less activity than NaS. Ascorbic acid showed no tumor promoting activity.(ABSTRACT TRUNCATED AT 400 WORDS)

It has been shown that Polycar prepared from sodium carbonate byproducts, intended for the treatment of potatoes before its storage, makes for an increase in solanine content, and a decrease in the level of ascorbic acid in potato. Such potato produces a toxic effect on the rat body. A conclusion has been made that Polycar could not be used as an agent for potato treatment.

It is well known that infection-induced stones (apatite, struvite), uric acid and cystine calculi in the urinary tract can be managed by the use of certain chemical solutions. We investigated the effects of various acidic and alkaline solutions on the rabbit urothelium. Acidic solutions (pH: 4.2) caused more urothelial injury as compared to alkaline solutions (pH: 7.6). Ureteral injury was more severe than the bladder injury. Magnesium-containing solutions caused less injury to the urothelium.

Large amounts of dolomite and bonemeal are being consumed, especially by nutrition-conscious persons. The mineral content of commercial samples has been analyzed by different laboratories, and significant amounts of lead, arsenic, mercury, and other potentially toxic metals, which also exist in conventional vitamin-mineral and calcium supplements, were detected. Physicians must consider the possibility of unrecognized self-poisoning from the consumption of such substances, especially in the context of unexplained neurologic, gastrointestinal, cutaneous, and hematologic disorders. The use of dolomite and bonemeal by pregnant women, children with suspected milk allergy, and elderly persons requires careful evaluation.

The use of the V79-4 system as a primary screen for fiber carcinogenicity is dependent on the observed correlation between cytotoxicity of the test material in the system and mesothelioma following intrapleural injection in animals. This correlation has been established for relatively pure samples of fibrous minerals. The wider application of the system as a screen for industrial dusts may depend on the ability of the system to show an unequivocal response to small yet significant percentages of fibrous dust in the presence of a large excess of nonfibrous material. Some materials tested, including platy minerals, show a response in the test which, while clearly less than that from UICC asbestos samples, could be construed as a positive result. Some, though not all, of these minerals show a nonlinear dose response in the test. This anomalous dose response may aid in the identification of some false positive results but the variety of responses to nonfibrous minerals places a limit on the predictive value of the test mixtures. Results obtained from mixtures of "standard" dust samples suggest this limit is reached at or above 10% fibrous content. Such levels would be significant in terms of human exposure. Extension of the concentration range tested does not improve the predictive value of the test.

Following implantation of 50-mg samples of a starch powder used for glove lubrication, or of talc or calcium carbonate mould-release agents for gloves, in the peritoneal cavity of rats, the treated animals were killed in groups of ten after 2, 4, 8, 13, 26 and 52 wk and were examined. Groups of sham-operated animals were used as controls. Within each treatment group the frequency of peritoneal adhesions remained constant throughout the study. Talc produced significantly more adhesions than the other treatments and caused a more severe granulomatous reaction, which persisted. Calcium carbonate and starch powder produced similar numbers of adhesions and in both cases the residues became invested by a thin fibrous capsule. Calcium carbonate appeared a safer material than talc.

'Shamma', also known as Yemeni snuff, is frequently used as a chewing material in Yemen and some parts of Saudi Arabia. Preliminary clinical observations indicated that long-term users of 'shamma' may develop oral cancer. A battery of in vitro bioassays were, therefore, used to test genotoxicity of this substance. The test systems included the histidine reversion assay in Ames' Salmonella strains, induction of aberrant colonies and tryptophan gene conversion in the D7 diploid strain of Saccharomyces cerevisiae, and oncogenic transformation of C3H mouse embryo 10T1/2 cells. Data indicated that direct-acting mutagen(s) were present in a chloroform extract of the powdered 'shamma' resulting in positive effects in all of the test systems used. Using high-performance liquid chromatography (HPLC), three major fractions were separated from the extract, of which two were found to be mutagenic.

Continuing the research--started in 1973--on the influence of wounds contamination by copper ore minerals upon the living organism the authors conducted experiments on 30 animals. The experiments covered: phagocytic and metabolic activity of peripheral blood phagocytes, oxidoreductase activity of granulocytes, lysosyme level in sera of the examined animals and total hemolytic activity of the complement. The experiments demonstrated--since the 20th day after their start--a considerable decrease in phagocytic and metabolic activity of peripheral blood granulocytes in the animals with wounds contaminated by copper ore minerals. Those disturbances may decrease nonspecific cellular immunity of the organism, which entails organism's susceptibility to infections.