Validation of a Method for the Determination of Total Chromium in Rat Feces by Inductively Coupled Plasma Optical Emission Spectrometry

Levine, Keith; Stout, Matthew D.; Ross, Gordon D.; Essader, Amal; Perlmutter, Jason; Grohse, Peter; Fernando, Reshan; Lang, Michelle; Collins, Bradley J.

doi:10.1080/00032710902721931

Cited by 6 publications

(5 citation statements)

References 16 publications

(12 reference statements)

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“…The sample preparation and analysis procedures used to determine the concentration of chromium in tissues (Levine et al, 2010) and excreta (Levine et al, 2009) in support of this investigation are presented in detail elsewhere and are summarized here. Neither of these procedures could differentiate between chromium oxidation states, so data reported are for total chromium, irrespective of oxidation state administered.…”

Section: Analysis Of Total Chromium In Tissues and Excretamentioning

confidence: 99%

Exposure to Hexavalent Chromium Resulted in Significantly Higher Tissue Chromium Burden Compared With Trivalent Chromium Following Similar Oral Doses to Male F344/N Rats and Female B6C3F1 Mice

Collins

Stout

Levine

et al. 2010

Toxicological Sciences

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In National Toxicology Program 2-year studies, hexavalent chromium [Cr(VI)] administered in drinking water was clearly carcinogenic in male and female rats and mice, resulting in small intestine epithelial neoplasms in mice at a dose equivalent to or within an order of magnitude of human doses that could result from consumption of chromium-contaminated drinking water, assuming that dose scales by body weight(3/4) (body weight raised to the 3/4 power). In contrast, exposure to trivalent chromium [Cr(III)] at much higher concentrations may have been carcinogenic in male rats but was not carcinogenic in mice or female rats. As part of these studies, total chromium was measured in tissues and excreta of additional groups of male rats and female mice. These data were used to infer the uptake and distribution of Cr(VI) because Cr(VI) is reduced to Cr(III) in vivo, and no methods are available to speciate tissue chromium. Comparable external doses resulted in much higher tissue chromium concentrations following exposure to Cr(VI) compared with Cr(III), indicating that a portion of the Cr(VI) escaped gastric reduction and was distributed systemically. Linear or supralinear dose responses of total chromium in tissues were observed following exposure to Cr(VI), indicating that these exposures did not saturate gastric reduction capacity. When Cr(VI) exposure was normalized to ingested dose, chromium concentrations in the liver and glandular stomach were higher in mice, whereas kidney concentrations were higher in rats. In vitro studies demonstrated that Cr(VI), but not Cr(III), is a substrate of the sodium/sulfate cotransporter, providing a partial explanation for the greater absorption of Cr(VI).

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Section: Analysis Of Total Chromium In Tissues and Excretamentioning

confidence: 99%

Exposure to Hexavalent Chromium Resulted in Significantly Higher Tissue Chromium Burden Compared With Trivalent Chromium Following Similar Oral Doses to Male F344/N Rats and Female B6C3F1 Mice

Collins

Stout

Levine

et al. 2010

Toxicological Sciences

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“…In response to the CrVI nomination, NTP conducted short-term and long-term toxicity and carcinogenicity studies on sodium dichromate dihydrate, a compound that contains hexavalent chromium. NTP’s products on CrVI included one toxicity report (TOX 72) ( Bucher 2007 ), one technical report (TR 546) ( NTP 2008 ), and five journal articles ( Figure 2 ) ( Collins et al 2010 ; Levine et al 2009 , 2010 ; Stout et al 2009 ; Witt et al 2013 ). TOX 72 described NTP’s 3-month studies of CrVI in drinking water in rodents and concluded that sodium dichromate dihydrate caused hyperplasia and ulceration of the stomach in rats, and anemia and lesions of the small intestine in rats and mice.…”

Section: Resultsmentioning

confidence: 99%

“…Intermediate outcomes, or citation metrics of NTP publications (reports and journal articles), were used as a metric of informing science in stakeholder groups. For NTP journal articles ( Collins et al 2010 ; Levine et al 2009 , 2010 ; Stout et al 2009 ; Witt et al 2013 ) citations in other journal articles (reviews, original research articles, and meta analysis) and book chapters were obtained from Web of Science ( Thomson Reuters 2016 ) and Scopus (2016) , which are online, subscription-based, scientific citation indexing services, through October 2014. NTP technical reports and toxicity reports are not fully indexed in Web of Science or Scopus.…”

Section: Methodsmentioning

confidence: 99%

Evaluating the Impact of the U.S. National Toxicology Program: A Case Study on Hexavalent Chromium

Yun¹,

Holmgren

Andrews³

et al. 2017

Environ Health Perspect

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Background:Evaluating the impact of federally funded research with a broad, methodical, and objective approach is important to ensure that public funds advance the mission of federal agencies.Objectives:We aimed to develop a methodical approach that would yield a broad assessment of National Toxicology Program’s (NTP’s) effectiveness across multiple sectors and demonstrate the utility of the approach through a case study.Methods:A conceptual model was developed with defined activities, outputs (products), and outcomes (proximal, intermediate, distal) and applied retrospectively to NTP’s research on hexavalent chromium (CrVI). Proximal outcomes were measured by counting views of and requests for NTP’s products by external stakeholders. Intermediate outcomes were measured by bibliometric analysis. Distal outcomes were assessed through Web and LexisNexis searches for documents related to legislation or regulation changes.Results:The approach identified awareness of NTP’s work on CrVI by external stakeholders (proximal outcome) and citations of NTP’s research in scientific publications, reports, congressional testimonies, and legal and policy documents (intermediate outcome). NTP’s research was key to the nation’s first-ever drinking water standard for CrVI adopted by California in 2014 (distal outcome). By applying this approach to a case study, the utility and limitations of the approach were identified, including challenges to evaluating the outcomes of a research program.Conclusions:This study identified a broad and objective approach for assessing NTP’s effectiveness, including methodological needs for more thorough and efficient impact assessments in the future.Citation:Xie Y, Holmgren S, Andrews DMK, Wolfe MS. 2017. Evaluating the impact of the U.S. National Toxicology Program: a case study on hexavalent chromium. Environ Health Perspect 125:181–188; http://dx.doi.org/10.1289/EHP21

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“…Several methods of feces analysis involve the lyophilization of the sample prior to digestion. [37] The amount of moisture lost during lyophilization may be related to the physical and chemical characteristics of the sample, suggesting that there could potentially be a link between the amount of moisture lost during sample preparation and the ability to obtain consistent recoveries of AgNPs. During this investigation, observed feces mass lost during lyophilization varied widely, ranging from 19.7-51.0%, while recoveries of AgNPs from those feces samples were found to range from 79.3-95.9%.…”

Section: Resultsmentioning

confidence: 99%

Development of an Analytical Method for Assessment of Silver Nanoparticle Content in Biological Matrices by Inductively Coupled Plasma Mass Spectrometry

Poitras

Levine

Harrington

et al. 2014

Biol Trace Elem Res

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Silver nanoparticles (AgNPs) are a broad class of synthetic nanoparticles that are utilized in a wide variety of consumer products as antimicrobial agents. Despite their widespread use, a detailed understanding of their toxicological characteristics and biological and environmental hazards is not available. To support research into the biodistribution and toxicology of AgNPs, it is necessary to develop a suitable method for the assessment of AgNP content in biological samples. Two methods were developed and validated to analyze citrate-coated AgNP content that utilize acid digestion of rodent feces and liver tissue samples and a third method was developed for the dilution and direct analysis of rodent urine samples. Following sample preparation, the silver content of each sample was determined by ICP-MS to quantify the silver and AgNP levels present. Analysis of rat feces matrix yielded analytical recoveries ranging from 82-93%. Liver tissue spiked with a formulation of AgNPs over a range of concentrations yielded analytical recoveries between 88 and 90%, providing acceptable accuracy results. The analysis of silver in urine samples exhibited recovery values ranging from 80-85% for AgNP formulations and 62-84% for standard silver ion solutions. All determinations exhibited a high degree of analytical precision. The results obtained here suggest that matrix interference plays a minimal role in AgNP recovery in feces and liver tissue, while the urine matrix can exhibit a significant effect on the determination of silver content.

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Validation of a Method for the Determination of Total Chromium in Rat Feces by Inductively Coupled Plasma Optical Emission Spectrometry

Cited by 6 publications

References 16 publications

Exposure to Hexavalent Chromium Resulted in Significantly Higher Tissue Chromium Burden Compared With Trivalent Chromium Following Similar Oral Doses to Male F344/N Rats and Female B6C3F1 Mice

Exposure to Hexavalent Chromium Resulted in Significantly Higher Tissue Chromium Burden Compared With Trivalent Chromium Following Similar Oral Doses to Male F344/N Rats and Female B6C3F1 Mice

Evaluating the Impact of the U.S. National Toxicology Program: A Case Study on Hexavalent Chromium

Development of an Analytical Method for Assessment of Silver Nanoparticle Content in Biological Matrices by Inductively Coupled Plasma Mass Spectrometry

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