1
|
Virk RK, Garla R, Kaushal N, Bansal MP, Garg ML, Mohanty BP. The relevance of arsenic speciation analysis in health & medicine. CHEMOSPHERE 2023; 316:137735. [PMID: 36603678 DOI: 10.1016/j.chemosphere.2023.137735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/24/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
Long term exposure to arsenic through consumption of contaminated groundwater has been a global issue since the last five decades; while from an alternate standpoint, arsenic compounds have emerged as unparallel chemotherapeutic drugs. This review highlights the contribution from arsenic speciation studies that have played a pivotal role in the progression of our understanding of the biological behaviour of arsenic in humans. We also discuss the limitations of the speciation studies and their association with the interpretation of arsenic metabolism. Chromatographic separation followed by spectroscopic detection as well as the utilization of biotinylated pull-down assays, protein microarray and radiolabelled arsenic have been instrumental in identifying hundreds of metabolic arsenic conjugates, while, computational modelling has predicted thousands of them. However, these species exhibit a variegated pattern, which supports more than one hypothesis for the metabolic pathway of arsenic. Thus, the arsenic species are yet to be integrated into a coherent mechanistic pathway depicting its chemicobiological fate. Novel biorelevant arsenic species have been identified due to significant evolution in experimental methodologies. However, these methods are specific for the identification of only a group of arsenicals sharing similar physiochemical properties; and may not be applicable to other constituents of the vast spectrum of arsenic species. Consequently, the identity of arsenic binding partners in vivo and the sequence of events in arsenic metabolism are still elusive. This resonates the need for additional focus on the extraction and characterization of both low and high molecular weight arsenicals in a combinative manner.
Collapse
Affiliation(s)
- Rajbinder K Virk
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| | - Roobee Garla
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| | - Naveen Kaushal
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| | - Mohinder P Bansal
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| | - Mohan L Garg
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| | - Biraja P Mohanty
- Department of Biophysics, Panjab University, Chandigarh, 160014, India.
| |
Collapse
|
2
|
Hirano S. Biotransformation of arsenic and toxicological implication of arsenic metabolites. Arch Toxicol 2020; 94:2587-2601. [PMID: 32435915 DOI: 10.1007/s00204-020-02772-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/04/2020] [Indexed: 12/13/2022]
Abstract
Arsenic is a well-known environmental carcinogen and chronic exposure to arsenic through drinking water has been reported to cause skin, bladder and lung cancers, with arsenic metabolites being implicated in the pathogenesis. In contrast, arsenic trioxide (As2O3) is an effective therapeutic agent for the treatment of acute promyelocytic leukemia, in which the binding of arsenite (iAsIII) to promyelocytic leukemia (PML) protein is the proposed initial step. These findings on the two-edged sword characteristics of arsenic suggest that after entry into cells, arsenic reaches the nucleus and triggers various nuclear events. Arsenic is reduced, conjugated with glutathione, and methylated in the cytosol. These biotransformations, including the production of reactive metabolic intermediates, appear to determine the intracellular dynamics, target organs, and biological functions of arsenic.
Collapse
Affiliation(s)
- Seishiro Hirano
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
| |
Collapse
|
3
|
Liamtsau V, Fan C, Liu G, McGoron AJ, Cai Y. Speciation of thioarsenicals through application of coffee ring effect on gold nanofilm and surface-enhanced Raman spectroscopy. Anal Chim Acta 2020; 1106:88-95. [PMID: 32145859 DOI: 10.1016/j.aca.2020.01.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 01/15/2020] [Accepted: 01/18/2020] [Indexed: 10/25/2022]
Abstract
Thioarsenicals, such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), have been increasingly discovered as important arsenic metabolites, yet analysis of these unstable arsenic species remains a challenging task. A method based on surface-enhanced Raman spectroscopy (SERS) detection in combination with the coffee ringeffect for separation is expected to be particularly useful for analysis of thioarsenicals, thanks to minimal sample pretreatment and unique fingerprint Raman identification. Such a method would offer an alternative approach that overcomes limitations of conventional arsenic speciation techniques based on high performance liquid chromatography separation and mass spectrometry detection. A novel analytical method based on combination of the coffee ringeffect and SERS was developed for the speciation of thiolated arsenicals. A gold nanofilm (AuNF) was employed not only as a SERS substrate, but also as a platform for the separation of thioarsenicals. Once a drop of the thioarsenicals solution was placed onto the AuNF and evaporation of the solvent and the ring stamp formation onto AuNF began, the SERS signal intensity substantially increased from center to edge regions of the evaporated droplet due to the presence of the coffee ring effect. Through calculating the pKa's of DMMTAV and DMDTAV and accordingly manipulating the chemical environment, separation of these thioarsenicals was realized as they travelled different distances during the development of the coffee ring. The migration distances of individual species were influenced by a radial outward flow of a solute, the thioarsenicals-AuNF interactions and a thermally induced Marangoni flow. The separation of DMMTAV (center) and DMDTAV (edge) on the coffee ring, in combination with fingerprint SERS spectra, enables the identification of these thioarsenicals by this AuNF-based coffee ring effect-SERS method.
Collapse
Affiliation(s)
- Valery Liamtsau
- Department of Chemistry and Biochemistry, Florida International University, Miami, 11200 SW 8th ST, Miami, FL, 33199, USA
| | - Changjun Fan
- Department of Chemistry and Biochemistry, Florida International University, Miami, 11200 SW 8th ST, Miami, FL, 33199, USA
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, 11200 SW 8th ST, Miami, FL, 33199, USA
| | - Anthony J McGoron
- Biomedical Engineering Department, Florida International University, 10555 West Flagler Street, EC 2442, Miami, FL, 33174, USA
| | - Yong Cai
- Department of Chemistry and Biochemistry, Florida International University, Miami, 11200 SW 8th ST, Miami, FL, 33199, USA; Southwest Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL, 33199, USA.
| |
Collapse
|
4
|
Yang M, Liamtsau V, Fan C, Sylvers KL, McGoron AJ, Liu G, Fu F, Cai Y. Arsenic Speciation on Silver Nanofilms by Surface-Enhanced Raman Spectroscopy. Anal Chem 2019; 91:8280-8288. [PMID: 31199622 DOI: 10.1021/acs.analchem.9b00999] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Surface-enhanced Raman spectroscopy (SERS), as a nondestructive and fast detection technique, is a promising alternative approach for arsenic detection, particularly for in situ applications. SERS-based speciation analysis according to the fingerprint SERS signals of different arsenicals has the potential to provide a superior technique in species preservation over the conventional chromatographic separation methods, albeit with some difficulties due to the similarity in SERS patterns. In this study, we explored a novel SERS method for arsenic speciation by using the separation potential of the coffee ring effect on negatively charged silver nanofilms (AgNFs). Four arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), were measured for fingerprint SERS signals in solution and on the films. Significant enhancement of SERS signals on the dried coffee ring stains by the AgNFs were observed except for AsIII, and more importantly, arsenicals migrated varying distances during coffee ring development, promoting better speciation. Sodium dodecyl sulfate was then introduced into the droplet to reduce the droplet surface tension, facilitating the migration of solution into the peripheral region. Under the combined interactions of arsenicals with the AgNFs, solvent, and surfactant, enhanced separation between arsenicals was observed as a result of the formation of two concentric rings. Combining the SERS fingerprint signals and physical separation of arsenicals on the surface, arsenic speciation was achieved using the AgNFs substrate-based SERS technology, demonstrating the potential of the coffee ring effect for rapid separation and analysis of small molecules by SERS.
Collapse
Affiliation(s)
| | | | | | - Kelli L Sylvers
- Department of Chemistry and Physical Sciences , The College of St. Scholastica , 1200 Kenwood Avenue , Duluth , Minnesota 55811 , United States
| | - Anthony J McGoron
- Biomedical Engineering Department , Florida International University , 10555 West Flagler Street , Miami , Florida 33174 , United States
| | | | - Fengfu Fu
- College of Chemistry , Fuzhou University , Fuzhou , Fujian 350116 , China
| | | |
Collapse
|
5
|
Herath I, Vithanage M, Seneweera S, Bundschuh J. Thiolated arsenic in natural systems: What is current, what is new and what needs to be known. ENVIRONMENT INTERNATIONAL 2018; 115:370-386. [PMID: 29705693 DOI: 10.1016/j.envint.2018.03.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/15/2018] [Accepted: 03/18/2018] [Indexed: 06/08/2023]
Abstract
Thiolated arsenic compounds are the sulfur analogous substructures of oxo-arsenicals as the arsinoyl (As = O) is substituted by an arsinothioyl (As = S) group. Relatively brief history of thioarsenic research, mostly in the current decade has endeavored to understand their consequences in the natural environment. However, thioarsenic related aspects have by far not attached much research concern on global scale compared to other arsenic species. This review attempts to provide a critical overview for the first time on formation mechanisms of thioarsenicals, their chemistry, speciation and analytical methodologies in order to provide a rational assessment of what is new, what is current, what needs to be known or what should be done in future research. Thioarsenic compounds play a vital role in determining the biogeochemistry of arsenic in sulfidic environments under reducing conditions. Thioarsenic species are widely immobilized by naturally occurring processes such as the adsorption on iron (oxyhydr)oxides and precipitation on iron sulfide minerals. Accurate measurement of thioarsenic species is a challenging task due to their instability upon pH, temperature, redox potential, and concentrations of oxygen, sulfur and iron. Assessment of direct and indirect effects of toxic thioarsenic species on global population those who frequently get exposed to high levels of arsenic is an urgent necessity. Dimethylmonothioarsinic acid (DMMTAV) is the most cytotoxic arsenic metabolite having similar toxicological effects as dimethylarsinous acid (DMAIII) in human and animal tissues. The formation and chemical analysis of thioarsenicals in soil and sediments are highly unknown. Therefore, future research needs to be more inclined towards in determining the molecular structure of unknown thioarsenic complexes in various environmental suites. Contemporary approaches hyphenated to existing technologies would pave the way to overcome critical challenges of thioarsenic speciation such as standards synthesis, structural determination, quantification and sample preservation in future research.
Collapse
Affiliation(s)
- Indika Herath
- School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, 4350 Toowoomba, Queensland, Australia
| | - Meththika Vithanage
- International Centre for Applied Climate Science, University of Southern Queensland, West Street, Toowoomba, 4350, Queensland, Australia; Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda 10250, Sri Lanka
| | - Saman Seneweera
- Plant Stress Biology Research Group, Centre for Crop Health, University of Southern Queensland, West Street, Toowoomba, 4350, Queensland, Australia
| | - Jochen Bundschuh
- School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, 4350 Toowoomba, Queensland, Australia; UNESCO Chair on Groundwater Arsenic within the 2030 Agenda for Sustainable Development, University of Southern Queensland, West Street, 4350 Toowoomba, Queensland, Australia.
| |
Collapse
|
6
|
Yang M, Sun Y, Zhang X, McCord B, McGoron AJ, Mebel A, Cai Y. Raman spectra of thiolated arsenicals with biological importance. Talanta 2018; 179:520-530. [DOI: 10.1016/j.talanta.2017.11.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 12/01/2022]
|
7
|
Potential application of SERS for arsenic speciation in biological matrices. Anal Bioanal Chem 2017; 409:4683-4695. [DOI: 10.1007/s00216-017-0434-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/30/2017] [Accepted: 05/26/2017] [Indexed: 01/01/2023]
|
8
|
Sun Y, Liu G, Cai Y. Thiolated arsenicals in arsenic metabolism: Occurrence, formation, and biological implications. J Environ Sci (China) 2016; 49:59-73. [PMID: 28007180 DOI: 10.1016/j.jes.2016.08.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
Arsenic (As) is a notoriously toxic pollutant of health concern worldwide with potential risk of cancer induction, but meanwhile it is used as medicines for the treatment of different conditions including hematological cancers. Arsenic can undergo extensive metabolism in biological systems, and both toxicological and therapeutic effects of arsenic compounds are closely related to their metabolism. Recent studies have identified methylated thioarsenicals as a new class of arsenic metabolites in biological systems after exposure of inorganic and organic arsenicals, including arsenite, dimethylarsinic acid (DMAV), dimethylarsinous glutathione (DMAIIIGS), and arsenosugars. The increasing detection of thiolated arsenicals, including monomethylmonothioarsonic acid (MMMTAV), dimethylmonothioarsinic acid (DMMTAV) and its glutathione conjugate (DMMTAVGS), and dimethyldithioarsinic acid (DMDTAV) suggests that thioarsenicals may be important metabolites and play important roles in arsenic toxicity and therapeutic effects. Here we summarized the reported occurrence of thioarsenicals in biological systems, the possible formation pathways of thioarsenicals, and their toxicity, and discussed the biological implications of thioarsenicals on arsenic metabolism, toxicity, and therapeutic effects.
Collapse
Affiliation(s)
- Yuzhen Sun
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Guangliang Liu
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yong Cai
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China; Department of Chemistry and Biochemistry&Southeast Environmental Research Center, Florida International University, Miami, FL 33199, USA.
| |
Collapse
|
9
|
Stice S, Liu G, Matulis S, Boise LH, Cai Y. Determination of multiple human arsenic metabolites employing high performance liquid chromatography inductively coupled plasma mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1009-1010:55-65. [PMID: 26708625 PMCID: PMC4748725 DOI: 10.1016/j.jchromb.2015.12.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 12/05/2015] [Indexed: 02/01/2023]
Abstract
During the metabolism of different arsenic-containing compounds in human, a variety of metabolites are produced with significantly varying toxicities. Currently available analytical methods can only detect a limited number of human metabolites in biological samples during one run due to their diverse characteristics. In addition, co-elution of species is often unnoticeable with most detection techniques leading to inaccurate metabolic profiles and assessment of toxicity. A high performance liquid chromatography inductively coupled mass spectrometry (HPLC-ICP-MS) method was developed that can identify thirteen common arsenic metabolites possibly present in human with special attention dedicated to thiolated or thiol conjugated arsenicals. The thirteen species included in this study are arsenite (As(III)), arsino-glutathione (As(GS)3), arsenate (As(V)), monomethylarsonous acid (MMA(III)), monomethylarsino-glutathione (MMA(III)(GS) 2), monomethylarsonic acid (MMA(V)), dimethylarsinous acid (DMA(III) (from DMA(III)I)), S-(dimethylarsinic)cysteine (DMA(III) (Cys)), dimethylarsino-glutathione (DMA(III)(GS)), dimethylarsinic acid (DMA(V)), dimethylmonothioarsinic acid (DMMTA(V)), dimethyldithioarsinic acid (DMDTA(V)), dimethylarsinothioyl glutathione (DMMTA(V)(GS)). The developed method was applied for the analysis of cancer cells that were incubated with darinaparsin (DMA(III)(GS)), a novel chemotherapeutic agent for refractory malignancies, and the arsenic metabolic profile obtained was compared to results using a previously developed method. This method provides a useful analytical tool which is much needed in unequivocally identifying the arsenicals formed during the metabolism of environmental arsenic exposure or therapeutic arsenic administration.
Collapse
Affiliation(s)
- Szabina Stice
- Department of Chemistry & Biochemistry, FL International University, 11200 SW 8th St., Miami, FL 33199, United States
| | - Guangliang Liu
- Department of Chemistry & Biochemistry, FL International University, 11200 SW 8th St., Miami, FL 33199, United States
| | - Shannon Matulis
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States
| | - Lawrence H Boise
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States
| | - Yong Cai
- Department of Chemistry & Biochemistry, FL International University, 11200 SW 8th St., Miami, FL 33199, United States; Southeast Environmental Research Center, FL International University, Miami, FL 33199, United States.
| |
Collapse
|
10
|
Yehiayan L, Stice S, Liu G, Matulis S, Boise LH, Cai Y. Dimethylarsinothioyl glutathione as a metabolite in human multiple myeloma cell lines upon exposure to Darinaparsin. Chem Res Toxicol 2014; 27:754-64. [PMID: 24624948 PMCID: PMC4027956 DOI: 10.1021/tx400386c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Here, we report the identification
of dimethylarsinothioyl glutathione
(DMMTAV(GS)) as a metabolite in cellular extracts of dimethyarsinous
glutathione (Darinaparsin, DMAIII(GS)) treated human multiple
myeloma (MM) cell lines. Co-elution of sulfur and arsenic on the inductively
coupled plasma mass spectrometer (ICP-MS) indicated the presence of
sulfur along with arsenic in the newly observed unidentified molecule
on the speciation chromatograms of cell lines treated with DMAIII(GS). Liquid chromatography–electrospray ionization–mass
spectrometry of the unknown peak in the MS and tandem MS modes revealed
molecular ion peaks at m/z = 443.9
and 466.0, corresponding to [DMMTAV(GS) + H]+ and [DMMTAV(GS) + Na]+, as well as peaks at
314.8 for the loss of glutamic acid and 231.1 for the loss of glycine.
In addition, peaks were observed at 176.9 corresponding to cysteine
and glycine adducts and at 137.1 for the [C2H6AsS]+ ion. An increase in the peak area of the unidentified
peak was observed upon spiking the cell extracts with a standard of
DMMTAV(GS). Heat deactivation of MM cells prevented the
formation of DMMTAV(GS) raising the possibility of its
formation via an enzymatic reaction. Formation studies in DMAIII(GS) treated MM cells revealed the dependence of DMMTAV(GS) formation on the depletion of DMAIII(GS).
The presence of 5 mM glutathione prevented its formation, indicating
that DMAIII, a dissociation product of DMAIII(GS), is likely a precursor for the formation of DMMTAV(GS). DMMTAV(GS) was observed to form under acidic and
neutral pH conditions (pH 3.0–7.4). In addition, DMMTAV(GS) was found to be stable in cell extracts at both acidic
and neutral pH conditions. When assessing the toxicity by exposing
multiple myeloma cells to arsenicals externally, DMMTAV(GS) was found to be much less toxic than DMAIII(GS) and
DMMTAV, potentially due to its limited uptake in the cells
(10 and 16% of the uptakes of DMAIII(GS) and DMMTAV, respectively).
Collapse
Affiliation(s)
- Lucy Yehiayan
- Department of Chemistry & Biochemistry, Florida International University , 11200 SW Eighth Street, Miami, Florida 33199, United States
| | | | | | | | | | | |
Collapse
|
11
|
Watanabe T, Hirano S. Metabolism of arsenic and its toxicological relevance. Arch Toxicol 2012; 87:969-79. [PMID: 22811022 DOI: 10.1007/s00204-012-0904-5] [Citation(s) in RCA: 196] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 07/02/2012] [Indexed: 10/28/2022]
Abstract
Arsenic is a worldwide environmental pollutant and a human carcinogen. It is well recognized that the toxicity of arsenicals largely depends on the oxidoreduction states (trivalent or pentavalent) and methylation levels (monomethyl, dimethyl, and trimethyl) that are present during the process of metabolism in mammals. However, presently, the specifics of the metabolic pathway of inorganic arsenicals have yet to be confirmed. In mammals, there are two possible mechanisms that have been proposed for the metabolic pathway of inorganic arsenicals, oxidative methylation, and glutathione conjugation. Oxidative methylation, which was originally proposed in fungi, is based on findings that arsenite (iAs(III)) is sequentially converted to monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) in both humans and in laboratory animals such as mice and rats. However, recent in vitro observations have demonstrated that arsenic is only methylated in the presence of glutathione (GSH) or other thiol compounds, which strongly suggests that arsenic is methylated in trivalent forms. The glutathione conjugation mechanism is supported by findings that have shown that most intracellular arsenicals are trivalent and excreted from cells as GSH conjugates. Since non-conjugated trivalent arsenicals are highly reactive with thiol compounds and are easily converted to less toxic corresponding pentavalent arsenicals, the arsenic-glutathione conjugate stability may be the most important factor for determining the toxicity of arsenicals. In addition, "being a non-anionic form" also appears to be a determinant of the toxicity of oxo-arsenicals or thioarsenicals. The present review discusses both the metabolism of arsenic and the toxicity of arsenic metabolites.
Collapse
Affiliation(s)
- Takayuki Watanabe
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo, Chiba 260-0856, Japan
| | | |
Collapse
|