Fibrous ferrierite from Lovelock, Nevada, USA

2020 ◽  
Author(s):  
Alessandro Gualtieri ◽  
Alessandro Zoboli ◽  
Dario Di Giuseppe ◽  
Cecilia Baraldi ◽  
Maria Cristina Gamberini ◽  
...  
Keyword(s):  
Thermal Analyses ◽  
Crystal Habit ◽  
International Agency ◽  
Mining Operations ◽  
Transmission Electron ◽  
Mineral Fibre ◽  
Microscopy Techniques ◽  
Different Content

<p>Ferrierite is the name of a family of zeolite minerals that includes three species with the same topological framework (FER) but with different content of extra-framework cations. In Nevada (USA), the zeolite-rich tuff deposit of Lovelock is the largest occurrence of diagenetic ferrierite-Mg, one of the member of the family. Recent studies have shown that Lovelock ferrierite can exhibit fibrous-asbestiform crystal habit and may possess the same physical-chemical and crystallographic properties of carcinogenic fibrous erionite, Nevertheless, it has not yet been classified by the International Agency for Research on Cancer (IARC). Nowadays, outcrops hosting fibrous ferrierite are being mined in Nevada for commercial purposes. Dust generated by these excavation activities may expose workforces and general public to this potential natural hazard. The main goal of this study was to perform a mineralogical and morphometric characterisation of the tuff deposit at Lovelock and evaluate the distribution of fibrous ferrierite in the outcrop. For this purpose, a multi-analytical approach including X-ray powder diffraction, scanning and transmission electron microscopy techniques, micro-Raman spectroscopy, thermal analyses, and surface-area determination was applied. The results indicate that fibrous ferrierite is widespread in the deposit and intermixed with mordenite and feldspar, although there are variations in the spatial distribution in the bedrock. The crystal habit of the ferrierite ranges from prismatic to asbestiform (elongated, thin and slightly flexible) and fibres are aggregated in bundles. According to the WHO counting criteria, most of the ferrierite fibres can be classified as breathable. While waiting for confirmatory in vitro and in vivo tests to assess the actual toxicity/pathogenicity potential of this mineral fibre, it is recommended to adopt a precautionary approach for mining operations in this area to reduce the risk of exposure.</p>

Characterisation of fibrous ferrierite in the rhyolitic tuffs at Lovelock, Nevada, USA

2019 ◽  
Vol 83 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Alessandro Zoboli ◽  
Dario Di Giuseppe ◽  
Cecilia Baraldi ◽  
Maria Cristina Gamberini ◽  
Daniele Malferrari ◽  
...  
Keyword(s):  
Thermal Analyses ◽  
Local Population ◽  
Crystal Habit ◽  
X Ray Diffraction ◽  
Mining Operations ◽  
Precautionary Approach ◽  
Mineral Fibre ◽  
Fibrous Morphology

AbstractFerrierite is the name for a series of zeolite-group of minerals which includes three species with the same ferrierite framework (FER) crystal structure but different extra-framework cations. Recent studies have shown that ferrierite can exhibit a fibrous-asbestiform crystal habit and may possess the same properties as carcinogenic fibrous erionite. Characterisation of the ferrierite in and around a mine location will be helpful in assessing the potential for toxic outcomes of exposure in the mine and any local population.The zeolite-rich tuff deposit of Lovelock, Nevada, USA is the largest occurrence of diagenetic ferrierite-Mg. A previous survey reported that ferrierite hosted in these rocks displays a fibrous morphology. However, these observations concerned a limited number of samples and until now there has been little evidence of widespread occurrence of fibrous ferrierite in the Lovelock deposit.The main goal of this study was to perform a mineralogical and morphometric characterisation of the tuff deposit at Lovelock and evaluate the distribution of fibrous ferrierite in the outcrop. For this purpose, a multi-analytical approach including powder X-ray diffraction, scanning and transmission microscopies, micro-Raman spectroscopy, thermal analyses, and surface-area determination was applied.The results prove fibrous ferrierite is widespread and intermixed with mordenite and orthoclase, although there are variations in the spatial distribution in the bedrock. The crystal habit of the ferrierite ranges from prismatic to asbestiform (elongated, thin and slightly flexible) and fibres are aggregated in bundles. According to the WHO counting criteria, most of the ferrierite fibres can be classified as breathable. While waiting for confirmatory in vitro and in vivo tests to assess the actual toxicity/pathogenicity potential of this mineral fibre, it is recommended to adopt a precautionary approach for mining operations in this area to reduce the risk of exposure.

Assessment of the potential health hazard of fibrous glaucophane

2020 ◽  
Author(s):  
Dario Di Giuseppe ◽  
Alessandro Gualtieri ◽  
Alessandro Zoboli ◽  
Monica Filaferro ◽  
Giovanni Vitale ◽  
...  
Keyword(s):  
Health Hazard ◽  
Toxicity Tests ◽  
International Agency ◽  
Potential Toxicity ◽  
Potential Health ◽  
Franciscan Complex ◽  
Mineral Fibre ◽  
Potential Health Hazard

<p>The widespread concern on the environmental hazards and public health issues related to exposure to respirable dusts from naturally occurring asbestos (NOA) in principle should also apply to deposits of mineral fibres other than the currently regulated six asbestos minerals. Recent studies highlight that glaucophane can assume a fibrous habit resembling the regulated amphibole asbestos minerals. Glaucophane, sometimes occurring in a fibrous habit, is a major mineral component of blueschist rocks of the Franciscan Complex, USA. Recently, fibrous blueschist occurrences within the Franciscan Complex were being excavated in California for construction purposes (<em>e.g.</em>, the Calaveras Dam Replacement Project) and concern existed that the dust generated by the excavation activities might potentially expose workers and the general public to health risks. For this reason, fibrous glaucophane (Gla) was considered to represent a potential health hazard as NOA by the dam owner, the San Francisco Public Utilities Commission, though an evaluation of the potential health hazard of this mineral fibre was not mandatory per local state and federal regulations. To fill this gap, the potential toxicity/pathogenicity of Gla from the Franciscan Complex has been assessed using the fibre potential toxicity model (FPTI) model and specific <em>in vitro</em> toxicity tests. FPTI is an analytical tool to predict the toxicity/pathogenicity of minerals fibers, based on physical/chemical and morphological parameters that induce biochemical mechanisms responsible for <em>in vivo</em> adverse effects. This model delivers an FPTI index aimed at ranking the toxicity and pathogenicity of a mineral fibre. Compared to asbestos minerals, the FPTI of Gla is considerably higher than that of chrysotile, comparable to that of tremolite and lower than that of crocidolite. Biological responses of cultured human lung cells (THP-1 and Met-5A) following 24 and 48h of exposure to different doses of Gla (25, 50 and 100 µg/mL), have been determined by Alamar Blue viability, Extra-cellular lactate dehydrogenase (LDH) and Comet assays. Generation of reactive oxygen species (ROS) has been evaluated performing the luminescent ROS-Glo™ assay. Crocidolite UICC asbestos (100 µg/mL) was also tested for comparison. Results of in vitro tests showed that Gla may induce a decrease in cell viability and an increase in LDH release in tested cell cultures in a concentration dependent mode. Overall, the rank of the investigated fibres in increasing order of cytotoxicity is: Gla (25 μg/mL) < Gla (50 μg/mL) < crocidolite (50 μg/mL) < Gla (100 μg/mL). For both the cells lines, Gla was able to induce DNA damage. Moreover, it was found that Gla can induce the formation of ROS. The chemical-structural features and biological reactivity of Gla confirm that this mineral fibre is a toxic agent. Although Gla induced lower toxic effects compared to the carcinogenic crocidolite, the inhalation of its fibres may be hypothetically responsible for the development of lung diseases. For a conclusive understanding of the mechanisms of the cellular/tissues responses to fibrous glaucophane, <em>in vivo</em> animal tests should be performed and compared to our outcome to stimulate a critical evaluation and a classification by the International Agency for Research on Cancer (IARC).</p>

scholarly journals Cemp1-p3 Peptide Promotes the Transformation of Octacalcium Phosphate into Hydroxyapatite Crystals

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1131
Author(s):  
Maricela Santana ◽  
Gonzalo Montoya ◽  
Raúl Herrera ◽  
Lía Hoz ◽  
Enrique Romo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Octacalcium Phosphate ◽  
Sequence Motifs ◽  
Simple Method ◽  
Transmission Electron ◽  
Precursor Phase ◽  
Mineralized Tissues ◽  
Potent Growth

Dental cementum contains unique molecules that regulate the mineralization process in vitro and in vivo, such as cementum protein 1 (CEMP1). This protein possesses amino acid sequence motifs like the human recombinant CEMP1 with biological activity. This novel cementum protein 1-derived peptide (CEMP1-p3, from the CEMP1’s N-terminal domain: (QPLPKGCAAVKAEVGIPAPH), consists of 20 amino acids. Hydroxyapatite (HA) crystals could be obtained through the combination of the amorphous precursor phase and macromolecules such as proteins and peptides. We used a simple method to synthesize peptide/hydroxyapatite nanocomposites using OCP and CEMP1-p3. The characterization of the crystals through scanning electron microscopy (SEM), powder X-ray diffraction (XRD), high--resolution transmission electron microscopy (HRTEM), and Raman spectroscopy revealed that CEMP1-p3 transformed OCP into hydroxyapatite (HA) under constant ionic strength and in a buffered solution. CEMP1-p3 binds and highly adsorbs to OCP and is a potent growth stimulator of OCP crystals. CEMP1-p3 fosters the transformation of OCP into HA crystals with crystalline planes (300) and (004) that correspond to the cell of hexagonal HA. Octacalcium phosphate crystals treated with CEMP1-p3 grown in simulated physiological buffer acquired hexagonal arrangement corresponding to HA. These findings provide new insights into the potential application of CEMP1-p3 on possible biomimetic approaches to generate materials for the repair and regeneration of mineralized tissues, or restorative materials in the orthopedic field.

Abstract 531: Tie-2/Cre--Mediated Conditional Deletion of Lipid Phosphate Phosphatase-3 Reveals Its Role in Endothelial Cell Apoptosis

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Ishita Chatterjee ◽  
Kishore K Wary
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Genome Wide Association Study ◽  
Vascular Endothelial Cell ◽  
Protein Levels ◽  
Conditional Deletion ◽  
Transmission Electron ◽  
Increased Risk

Rationale: A recent genome-wide association study (GWAS) has linked a frequently occurring variation in the LPP3 (also known as PPAP2b) loci to increased risk of coronary heart disease (CAD). However, the in vivo function of LPP3 in vascular endothelial cell is incompletely understood. Goal: To address the endothelial cell (EC) specific function of Lpp3 in mice. Results: Tie-2/Cre mediated Lpp3 deletion did not affect normal vasculogenesis in early embryonic development, in contrast, in late embryonic stages it led to impaired angiogenesis associated with hemorrhage, edema and late embryonic lethal phenotype. Immunohistochemical staining followed by microscopic analyses of mutant embryos revealed reduced fibronectin and VE-cadherin expression throughout different vascular bed, and increased apoptosis in CD31+ vascular structures. Transmission electron microscopy (TEM) showed the presence of apoptotic endothelial cells and disruption of adherens junctions in mutant embryos. LPP3-knockdown in vitro showed an increase in p53 and p21 protein levels, with concomitant decrease in cell proliferation. LPP3-knockdown also decreased transendothelial electrical resistance (TER), interestingly re-expression of ß-catenin cDNA into LPP3-depleted endothelial cells partially restored the effect of loss of LPP3. Conclusion: These results suggest the ability of LPP3 to regulate survival and apoptotic activities of endothelial cells during patho/physiological angiogenesis.

scholarly journals Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

2010 ◽  
Vol 10 ◽  
pp. 879-893 ◽  
Author(s):  
Nathaniel G. N. Milton ◽  
J. Robin Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Islet Amyloid Polypeptide ◽  
Amyloid Β ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide ◽  
Transmission Electron

The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrilsin vitroandin vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KDof 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

scholarly journals Ivermectin induces autophagy-mediated cell death through the AKT/mTOR signaling pathway in glioma cells

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Jingjing Liu ◽  
Hongsheng Liang ◽  
Chen Chen ◽  
Xiaoxing Wang ◽  
Faling Qu ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Anticancer Agent ◽  
Glioma Cells ◽  
Mtor Signaling ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Transmission Electron ◽  
Diphenyltetrazolium Bromide

Abstract Glioma is one of the most common types of primary brain tumors. Ivermectin (IVM), a broad-spectrum antiparasitic drug, has been identified as a novel anticancer agent due to its inhibitory effects on the proliferation of glioma cells in vitro and in vivo. However, the ability of IVM to induce autophagy and its role in glioma cell death remains unclear. The main objective of the present study was to explore autophagy induced by IVM in glioma U251 and C6 cells, and the deep underlying molecular mechanisms. In addition, we examined the effects of autophagy on apoptosis in glioma cells. In the present study, transmission electron microscopy (TEM), immunofluorescence, Western blot and immunohistochemistry were used to evaluate autophagy activated by IVM. Cell viability was measured by 3-(4,5-dimethylthiazol2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and colony formation assay. The apoptosis rate was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Meanwhile, autophagy inhibition was achieved by using chloroquine (CQ). U251-derived xenografts were established for examination of IVM-induced autophagy on glioma in vivo. Taken together, the results of the present study showed that autophagy induced by IVM has a protective effect on cell apoptosis in vitro and in vivo. Mechanistically, IVM induced autophagy through AKT/mTOR signaling and induced energy impairment. Our findings show that IVM is a promising anticancer agent and may be a potential effective treatment for glioma cancers.

A Comparative Study of Bioceramics In Vitro and In Vivo

2005 ◽  
Vol 284-286 ◽  
pp. 11-14 ◽  
Author(s):  
Yang Leng ◽  
Ren Long Xin ◽  
Ji Yong Chen
Keyword(s):  
Calcium Phosphates ◽  
Glass Ceramics ◽  
Octacalcium Phosphate ◽  
Rabbit Muscle ◽  
In Vivo Experiments ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Dental Applications

Bioactive calcium phosphate (Ca-P) formation in bioceramics surfaces in simulated body fluid (SBF) and in rabbit muscle sites was investigated. The examined bioceamics included most commonly used bioglass®, A-W glass-ceramics and calcium phosphates in orthopedic and dental applications. The Ca-P cyrstal structures were examined with single crystal diffraction patterns in transmission electron microscopy, which reduced possibility of misidentifying Ca-P phases. The experimental results show that capability of Ca-P formation considerably varied among bioceramics, particularly in vivo. Octacalcium phosphate (OCP) was revealed on the all types of bioceramics in vitro and in vivo experiments. This work leads us to rethink how to evaluate bioactivity of bioceramics and other orthopedic materials which exhibit capability of osteoconduction by forming direct bonding with bone.

scholarly journals Autophagy Is Independent of the Chondroprotection Induced by Platelet-Rich Plasma Releasate

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Fan Yang ◽  
Haoran Hu ◽  
Wenjing Yin ◽  
Guangyi Li ◽  
Ting Yuan ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Interleukin 1 ◽  
Cartilage Degeneration ◽  
Inflammatory Stress ◽  
Catabolic Genes ◽  
Transmission Electron ◽  
Similar Expression Pattern ◽  
Vehicle Treatment

Background. Platelet-rich plasma (PRP) has been shown to be a promising therapeutic agent against osteoarthritis (OA), whereas its chondroprotection mechanism is not fully elucidated. Autophagy is considered an important biological process throughout the development of OA. Therefore, the objective of the present study is to investigate the role of autophagy in the chondroprotection and compare the effects of releasate between L-PRP and P-PRP. Methods. PRP were prepared from rat blood. Rat chondrocytes pretreated in the presence or absence of interleukin-1 beta (IL-1β) were incubated with PRP releasate. The expressions of OA-related genes and autophagy-related genes were determined by RT-PCR and western blot, respectively. Autophagic bodies were assessed by transmission electron microscopy and the autophagy flux was monitored under the confocal microscopy. The effect of PRP on autophagy was further investigated in the milieu of autophagy activator, rapamycin, or autophagy inhibition by downregulation of Atg5. The effect of PRP on cartilage repair and autophagy was also evaluated in an OA rat model. Results. In vitro, PRP releasate increased the expression of the anabolic genes, COL2 and Aggrecan, and decreased the expression of the catabolic genes, whereas the expression of autophage markers, Atg5 and Beclin-1, as well as the ratio of LC3 II/LC3 I, was not significantly altered in normal or IL-1β-treated chondrocytes. Similar expression pattern was found following the activation (rapamycin) or inhibition (Atg5 silencing) of autophagy. In vivo, PRP releasate ameliorated posttraumatic cartilage degeneration while the expression of LC3 was comparable to that in the vehicle treatment group. Conclusions. PRP releasate promoted the anabolic gene expression, relieved inflammatory stress in chondrocytes, and ameliorated cartilage degeneration, but autophagy was independent of these processes.

scholarly journals Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 263 ◽  
Author(s):  
Maria Letizia Manca ◽  
Iris Usach ◽  
José Esteban Peris ◽  
Antonella Ibba ◽  
Germano Orrù ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Yeast Cells ◽  
Unilamellar Vesicles ◽  
Transmission Electron ◽  
Physico Chemical

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

Yolk platelet degradation in preemergence Artemia embryos: response to protons in vivo and in vitro

1987 ◽  
Vol 252 (4) ◽  
pp. R774-R781 ◽  
Author(s):  
P. J. Utterback ◽  
S. C. Hand
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dry Weight ◽  
Platelet Protein ◽  
Transmission Electron ◽  
Structural Differences ◽  
Alkaline Conditions ◽  
Yolk Platelet

Alteration of intracellular pH (pHi) influences yolk platelet degradation during preemergence development in Artemia embryos. Cysts incubated for 10 h under conditions of aerobic development (aqueous medium equilibrated with 60% N2-40% O2, pHi greater than or equal to 7.9) exhibit a significant decrease in numbers of yolk platelets and platelet protein. In contrast, cysts incubated for 10 h under aerobic acidosis (60% CO2-40% O2, pHi = 6.8) show no significant decrease in numbers of yolk platelets or platelet protein. When subjected to alkaline conditions in vitro, yolk platelets release protein exponentially as a function of time. The process is essentially complete in 40 min. The extent of protein and lipid release from platelets increases markedly as pH of the medium is raised in increments from 6.3 to 8.0. Concomitant with these changes are reduction (50%) in platelet dry weight and reduction (21%) in platelet diameter. Transmission electron microscopy does not reveal major structural differences between isolated yolk platelets and those contained in hydrated embryos. The proton effects on platelet composition and size detected in vitro may explain in part the mechanism of platelet degradation observed during aerobic development and its suppression under conditions of acidic pHi.

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