Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-30 (of 34 Records) |
Query Trace: Sargent W[original query] |
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Implementation and adaptation of clinical quality improvement opioid measures
Hersey C , Shoemaker-Hunt S , Parchman M , Childs E , Le J , Sargent W . Healthc (Amst) 2024 12 (4) 100753 |
Potent lung tumor promotion by inhaled MWCNT
Porter DW , Orandle MS , Hubbs A , Staska LM , Lowry D , Kashon M , Wolfarth MG , McKinney W , Sargent LM . Nanotoxicology 2024 1-18 In the lung, carcinogenesis is a multi-stage process that includes initiation by a genotoxic agent, promotion that expands the population of cells with damaged DNA to form a tumor, and progression from benign to malignant neoplasms. We have previously shown that Mitsui-7, a long and rigid multi-walled carbon nanotube (MWCNT), promotes pulmonary carcinogenesis in a mouse model. To investigate the potential exposure threshold and dose-response for tumor promotion by this MWCNT, 3-methylcholanthrene (MC) initiated (10 μg/g, i.p., once) or vehicle (corn oil) treated B6C3F1 mice were exposed by inhalation to filtered air or MWCNT (5 mg/m(3)) for 5 h/day for 0, 2, 5, or 10 days and were followed for 17 months post-exposure for evidence of lung tumors. Pulmonary neoplasia incidence in MC-initiated mice significantly increased with each MWCNT exposure duration. Exposure to either MC or MWCNT alone did not affect pulmonary neoplasia incidence compared with vehicle controls. Lung tumor multiplicity in MC-initiated mice also significantly increased with each MWCNT exposure duration. Thus, a significantly higher lung tumor multiplicity was observed after a 10-day MWCNT exposure than following a 2-day exposure. Both bronchioloalveolar adenoma and bronchioloalveolar adenocarcinoma multiplicity in MC-initiated mice were significantly increased following 5- and 10-day MWCNT exposure, while a 2-day MWCNT exposure in MC-initiated mice significantly increased the multiplicity of adenomas but not adenocarcinomas. In this study, even the lowest MWCNT exposure promoted lung tumors in MC-initiated mice. Our findings indicate that exposure to this MWCNT strongly promotes pulmonary carcinogenesis. |
Supporting evidence-based care through informatics innovation to address the overdose epidemic
Sargent WM Jr , Mikosz CA , Baker EL . J Public Health Manag Pract 2023 29 (4) 598-600 The drug overdose crisis in the United States continues to evolve, driven by overdose deaths involving synthetic opioids, often in combination with other substances, highlighting the need for adapting and innovating evidence-based prevention and response strategies.1 The Centers for Disease Control and Prevention (CDC) reports that 106 699 Americans died of drug overdoses in 2021, an increase of nearly 14% from 93 655 deaths in 2020.2 As public health leaders engage in the complex process of prevention on a population and individual basis, close strategic partnerships between public health and health care delivery systems have become increasingly important. Informatics innovation offers a timely and practical avenue to enhance these partnerships. For example, a recent publication3 on the West Virginia Prescription Drug Monitoring Program (PDMP) demonstrated the benefit of informatics innovation to support clinical decision-making and surveillance as vital components of that state's strategic partnerships that focus on the opioid overdose epidemic. |
Achieving reductions in opioid dispensing: A qualitative comparative analysis of state-level efforts to improve prescribing
Underwood NL , Kane H , Cance J , Emery K , Elek E , Zule W , Rooks-Peck C , Sargent W , Mells J . J Public Health Manag Pract 2022 29 (2) 262-270 OBJECTIVE: To determine whether any combinations of state-level public health activities were necessary or sufficient to reduce prescription opioid dispensing. DESIGN: We examined 2016-2019 annual progress reports, 2014-2019 national opioid dispensing data (IQVIA), and interview data from states to categorize activities. We used crisp-set Qualitative Comparative Analysis to determine which program activities, individually or in combination, were necessary or sufficient for a better than average decrease in morphine milligram equivalent (MME) per capita. SETTING: Twenty-nine US state health departments. PARTICIPANTS: State health departments implementing the Centers for Disease Control and Prevention's Prevention for States (PfS) program. MAIN OUTCOME: Combinations of prevention activities related to changes in the rate of prescription opioid MME per capita dispensing from 2014 to 2019. RESULTS: Three combinations were sufficient for greater than average state-level reductions in MME per capita: (1) expanding and improving proactive reporting in combination with enhancing the uptake of evidence-based opioid prescribing guidelines and not moving toward a real-time Prescription Drug Monitoring Program; (2) implementing or improving prescribing interventions for insurers, health systems, or pharmacy benefit managers in combination with enhancing the uptake of evidence-based opioid prescribing guidelines; and (3) not implementing or improving prescribing interventions for insurers, health systems, or pharmacy benefit managers in combination with not enhancing the uptake of evidence-based opioid prescribing guidelines. Interview data suggested that the 3 combinations indicate how state contexts and history with addressing opioid overdose shaped programming and the ability to reduce MME per capita. CONCLUSIONS: States successful in reducing opioid dispensing selected activities that built upon existing policies and interventions, which may indicate thoughtful use of resources. To maximize impact in addressing the opioid overdose epidemic, states and agencies may benefit from building on existing policies and interventions. |
Prognostic indicators and outcomes of hospitalised COVID-19 patients with neurological disease: An individual patient data meta-analysis.
Singh B , Lant S , Cividini S , Cattrall JWS , Goodwin LC , Benjamin L , Michael BD , Khawaja A , Matos AMB , Alkeridy W , Pilotto A , Lahiri D , Rawlinson R , Mhlanga S , Lopez EC , Sargent BF , Somasundaran A , Tamborska A , Webb G , Younas K , Al Sami Y , Babu H , Banks T , Cavallieri F , Cohen M , Davies E , Dhar S , Fajardo Modol A , Farooq H , Harte J , Hey S , Joseph A , Karthikappallil D , Kassahun D , Lipunga G , Mason R , Minton T , Mond G , Poxon J , Rabas S , Soothill G , Zedde M , Yenkoyan K , Brew B , Contini E , Cysique L , Zhang X , Maggi P , van Pesch V , Lechien J , Saussez S , Heyse A , Brito Ferreira ML , Soares CN , Elicer I , Eugenín-von Bernhardi L , Ñancupil Reyes W , Yin R , Azab MA , Abd-Allah F , Elkady A , Escalard S , Corvol JC , Delorme C , Tattevin P , Bigaut K , Lorenz N , Hornuss D , Hosp J , Rieg S , Wagner D , Knier B , Lingor P , Winkler AS , Sharifi-Razavi A , Moein ST , SeyedAlinaghi S , JamaliMoghadamSiahkali S , Morassi M , Padovani A , Giunta M , Libri I , Beretta S , Ravaglia S , Foschi M , Calabresi P , Primiano G , Servidei S , Biagio Mercuri N , Liguori C , Pierantozzi M , Sarmati L , Boso F , Garazzino S , Mariotto S , Patrick KN , Costache O , Pincherle A , Klok FA , Meza R , Cabreira V , Valdoleiros SR , Oliveira V , Kaimovsky I , Guekht A , Koh J , Fernández Díaz E , Barrios-López JM , Guijarro-Castro C , Beltrán-Corbellini Á , Martínez-Poles J , Diezma-Martín AM , Morales-Casado MI , García García S , Breville G , Coen M , Uginet M , Bernard-Valnet R , Du Pasquier R , Kaya Y , Abdelnour LH , Rice C , Morrison H , Defres S , Huda S , Enright N , Hassell J , D'Anna L , Benger M , Sztriha L , Raith E , Chinthapalli K , Nortley R , Paterson R , Chandratheva A , Werring DJ , Dervisevic S , Harkness K , Pinto A , Jillella D , Beach S , Gunasekaran K , Rocha Ferreira Da Silva I , Nalleballe K , Santoro J , Scullen T , Kahn L , Kim CY , Thakur KT , Jain R , Umapathi T , Nicholson TR , Sejvar JJ , Hodel EM , Tudur Smith C , Solomon T . PLoS One 2022 17 (6) e0263595 BACKGROUND: Neurological COVID-19 disease has been reported widely, but published studies often lack information on neurological outcomes and prognostic risk factors. We aimed to describe the spectrum of neurological disease in hospitalised COVID-19 patients; characterise clinical outcomes; and investigate factors associated with a poor outcome. METHODS: We conducted an individual patient data (IPD) meta-analysis of hospitalised patients with neurological COVID-19 disease, using standard case definitions. We invited authors of studies from the first pandemic wave, plus clinicians in the Global COVID-Neuro Network with unpublished data, to contribute. We analysed features associated with poor outcome (moderate to severe disability or death, 3 to 6 on the modified Rankin Scale) using multivariable models. RESULTS: We included 83 studies (31 unpublished) providing IPD for 1979 patients with COVID-19 and acute new-onset neurological disease. Encephalopathy (978 [49%] patients) and cerebrovascular events (506 [26%]) were the most common diagnoses. Respiratory and systemic symptoms preceded neurological features in 93% of patients; one third developed neurological disease after hospital admission. A poor outcome was more common in patients with cerebrovascular events (76% [95% CI 67-82]), than encephalopathy (54% [42-65]). Intensive care use was high (38% [35-41]) overall, and also greater in the cerebrovascular patients. In the cerebrovascular, but not encephalopathic patients, risk factors for poor outcome included breathlessness on admission and elevated D-dimer. Overall, 30-day mortality was 30% [27-32]. The hazard of death was comparatively lower for patients in the WHO European region. INTERPRETATION: Neurological COVID-19 disease poses a considerable burden in terms of disease outcomes and use of hospital resources from prolonged intensive care and inpatient admission; preliminary data suggest these may differ according to WHO regions and country income levels. The different risk factors for encephalopathy and stroke suggest different disease mechanisms which may be amenable to intervention, especially in those who develop neurological symptoms after hospital admission. |
How effective are Fatigue Risk Management Systems (FRMS) A review
Sprajcer M , Thomas MJW , Sargent C , Crowther ME , Boivin DB , Wong IS , Smiley A , Dawson D . Accid Anal Prev 2021 165 106398 OBJECTIVE: Fatigue Risk Management Systems (FRMS) are a data-driven set of management practices for identifying and managing fatigue-related safety risks. This approach also considers sleep and work time, and is based on ongoing risk assessment and monitoring. This narrative review addresses the effectiveness of FRMS, as well as barriers and enablers in the implementation of FRMS. Furthermore, this review draws on the literature to provide evidence-based policy guidance regarding FRMS implementation. METHODS: Seven databases were drawn on to identify relevant peer-reviewed literature. Relevant grey literature was also reviewed based on the authors' experience in the area. In total, 2129 records were screened based on the search strategy, with 231 included in the final review. RESULTS: Few studies provide an evidence-base for the effectiveness of FRMS as a whole. However, FRMS components (e.g., bio-mathematical models, self-report measures, performance monitoring) have improved key safety and fatigue metrics. This suggests FRMS as a whole are likely to have positive safety outcomes. Key enablers of successful implementation of FRMS include organisational and worker commitment, workplace culture, and training. CONCLUSIONS: While FRMS are likely to be effective, in organisations where safety cultures are insufficiently mature and resources are less available, these systems may be challenging to implement successfully. We propose regulatory bodies consider a hybrid model of FRMS, where organisations could choose to align with tight hours of work (compliance) controls. Alternatively, where organisational flexibility is desired, a risk-based approach to fatigue management could be implemented. |
Physicochemical characterization and genotoxicity of the broad class of carbon nanotubes and nanofibers used or produced in U.S. facilities.
Fraser K , Kodali V , Yanamala N , Birch ME , Cena L , Casuccio G , Bunker K , Lersch TL , Evans DE , Stefaniak A , Hammer MA , Kashon ML , Boots T , Eye T , Hubczak J , Friend SA , Dahm M , Schubauer-Berigan MK , Siegrist K , Lowry D , Bauer AK , Sargent LM , Erdely A . Part Fibre Toxicol 2020 17 (1) 62 ![]() BACKGROUND: Carbon nanotubes and nanofibers (CNT/F) have known toxicity but simultaneous comparative studies of the broad material class, especially those with a larger diameter, with computational analyses linking toxicity to their fundamental material characteristics was lacking. It was unclear if all CNT/F confer similar toxicity, in particular, genotoxicity. Nine CNT/F (MW #1-7 and CNF #1-2), commonly found in exposure assessment studies of U.S. facilities, were evaluated with reported diameters ranging from 6 to 150 nm. All materials were extensively characterized to include distributions of physical dimensions and prevalence of bundled agglomerates. Human bronchial epithelial cells were exposed to the nine CNT/F (0-24 μg/ml) to determine cell viability, inflammation, cellular oxidative stress, micronuclei formation, and DNA double-strand breakage. Computational modeling was used to understand various permutations of physicochemical characteristics and toxicity outcomes. RESULTS: Analyses of the CNT/F physicochemical characteristics illustrate that using detailed distributions of physical dimensions provided a more consistent grouping of CNT/F compared to using particle dimension means alone. In fact, analysis of binning of nominal tube physical dimensions alone produced a similar grouping as all characterization parameters together. All materials induced epithelial cell toxicity and micronuclei formation within the dose range tested. Cellular oxidative stress, DNA double strand breaks, and micronuclei formation consistently clustered together and with larger physical CNT/F dimensions and agglomerate characteristics but were distinct from inflammatory protein changes. Larger nominal tube diameters, greater lengths, and bundled agglomerate characteristics were associated with greater severity of effect. The portion of tubes with greater nominal length and larger diameters within a sample was not the majority in number, meaning a smaller percentage of tubes with these characteristics was sufficient to increase toxicity. Many of the traditional physicochemical characteristics including surface area, density, impurities, and dustiness did not cluster with the toxicity outcomes. CONCLUSION: Distributions of physical dimensions provided more consistent grouping of CNT/F with respect to toxicity outcomes compared to means only. All CNT/F induced some level of genotoxicity in human epithelial cells. The severity of toxicity was dependent on the sample containing a proportion of tubes with greater nominal lengths and diameters. |
Developing clinical quality improvement measures aligned with the CDC Guideline for Prescribing Opioids for Chronic Pain: An important strategy to support safer prescribing in primary care
Shoemaker-Hunt S , Sargent WJr , Swan H , Mikosz C , Cobb K , McDonald D , Keane N , von Korff M , Parchman M , Losby J . Am J Med Qual 2020 36 (2) 125-128 In 2018, opioids were involved in 46 802 overdose deaths.1 To help address the opioid overdose epidemic, the Centers for Disease Control and Prevention (CDC) released its Guideline for Prescribing Opioids for Chronic Pain (CDC Prescribing Guideline) in March 2016. To support providers in implementing the guideline, a set of 16 quality improvement (QI) measures were developed that align with the CDC Prescribing Guideline. The goal of these QI measures is to provide health care systems with the means to track their progress in implementing recommended practices to improve care over time. As the QI adage states, “You cannot improve what you cannot measure.” |
Mitsui-7, heat-treated, and nitrogen-doped multi-walled carbon nanotubes elicit genotoxicity in human lung epithelial cells
Siegrist KJ , Reynolds SH , Porter DW , Mercer RR , Bauer AK , Lowry D , Cena L , Stueckle TA , Kashon ML , Wiley J , Salisbury JL , Mastovich J , Bunker K , Sparrow M , Lupoi JS , Stefaniak AB , Keane MJ , Tsuruoka S , Terrones M , McCawley M , Sargent LM . Part Fibre Toxicol 2019 16 (1) 36 BACKGROUND: The unique physicochemical properties of multi-walled carbon nanotubes (MWCNT) have led to many industrial applications. Due to their low density and small size, MWCNT are easily aerosolized in the workplace making respiratory exposures likely in workers. The International Agency for Research on Cancer designated the pristine Mitsui-7 MWCNT (MWCNT-7) as a Group 2B carcinogen, but there was insufficient data to classify all other MWCNT. Previously, MWCNT exposed to high temperature (MWCNT-HT) or synthesized with nitrogen (MWCNT-ND) have been found to elicit attenuated toxicity; however, their genotoxic and carcinogenic potential are not known. Our aim was to measure the genotoxicity of MWCNT-7 compared to these two physicochemically-altered MWCNTs in human lung epithelial cells (BEAS-2B & SAEC). RESULTS: Dose-dependent partitioning of individual nanotubes in the cell nuclei was observed for each MWCNT material and was greatest for MWCNT-7. Exposure to each MWCNT led to significantly increased mitotic aberrations with multi- and monopolar spindle morphologies and fragmented centrosomes. Quantitative analysis of the spindle pole demonstrated significantly increased centrosome fragmentation from 0.024-2.4 mug/mL of each MWCNT. Significant aneuploidy was measured in a dose-response from each MWCNT-7, HT, and ND; the highest dose of 24 mug/mL produced 67, 61, and 55%, respectively. Chromosome analysis demonstrated significantly increased centromere fragmentation and translocations from each MWCNT at each dose. Following 24 h of exposure to MWCNT-7, ND and/or HT in BEAS-2B a significant arrest in the G1/S phase in the cell cycle occurred, whereas the MWCNT-ND also induced a G2 arrest. Primary SAEC exposed for 24 h to each MWCNT elicited a significantly greater arrest in the G1 and G2 phases. However, SAEC arrested in the G1/S phase after 72 h of exposure. Lastly, a significant increase in clonal growth was observed one month after exposure to 0.024 mug/mL MWCNT-HT & ND. CONCLUSIONS: Although MWCNT-HT & ND cause a lower incidence of genotoxicity, all three MWCNTs cause the same type of mitotic and chromosomal disruptions. Chromosomal fragmentation and translocations have not been observed with other nanomaterials. Because in vitro genotoxicity is correlated with in vivo genotoxic response, these studies in primary human lung cells may predict the genotoxic potency in exposed human populations. |
An examination of concurrent opioid and benzodiazepine prescribing in 9 states, 2015
Guy GPJr , Zhang K , Halpin J , Sargent W . Am J Prev Med 2019 57 (5) 629-636 INTRODUCTION: Concurrent prescribing of opioids and benzodiazepines is discouraged by evidence-based clinical guidelines because of the known risks of taking these medications in combination. METHODS: This study analyzed concurrent opioid and benzodiazepine prescribing in 9 states using the 2015 Prescription Behavior Surveillance System, a multistate database of de-identified prescription drug monitoring program data. Concurrent prescribing rates were examined among individuals with both an opioid and a benzodiazepine prescription. Among patients with concurrent prescribing, total days of opioid supply, daily dosage of opioids, and total days of concurrent prescriptions were examined. Analyses were stratified by whether concurrent prescribing was from a single prescriber or multiple prescribers. Opioid prescribing and concurrent opioid and benzodiazepine prescribing rates were examined by age and sex. Analyses were conducted in 2018. RESULTS: Among 19,977,642 patients that were prescribed an opioid, 21.6% (4,324,092) were also prescribed a benzodiazepine, of which 54.9% (2,375,219) had concurrent prescriptions. More than half of patients with concurrent opioids and benzodiazepines received prescriptions from 2 or more distinct prescribers. Mean total opioid days, daily opioid dosage, and days of concurrent prescribing were higher among patients when multiple prescribers were involved compared with concurrent prescriptions from the same prescriber. Concurrent prescribing was more common among adults aged >/=50 years and female patients. CONCLUSIONS: Public health interventions are needed to reduce concurrent prescribing of opioids and benzodiazepines. Evidence-based guidelines can help reduce concurrent prescribing when one prescriber is involved, and utilization of prescription drug monitoring programs and improved care coordination could help address concurrent prescribing when multiple prescribers are involved. |
Role of p53 in the chronic pulmonary immune response to tangled or rod-like multi-walled carbon nanotubes
Duke KS , Thompson EA , Ihrie MD , Taylor-Just AJ , Ash EA , Shipkowski KA , Hall JR , Tokarz DA , Cesta MF , Hubbs AF , Porter DW , Sargent LM , Bonner JC . Nanotoxicology 2018 12 (9) 1-17 The fiber-like shape of multi-walled carbon nanotubes (MWCNTs) is reminiscent of asbestos, suggesting they pose similar health hazards when inhaled, including pulmonary fibrosis and mesothelioma. Mice deficient in the tumor suppressor p53 are susceptible to carcinogenesis. However, the chronic pathologic effect of MWCNTs delivered to the lungs of p53 heterozygous (p53(+/-)) mice has not been investigated. We hypothesized that p53(+/-) mice would be susceptible to lung tumor development after exposure to either tangled (t-) or rod-like (r-) MWCNTs. Wild-type (p53(+/+)) or p53(+/-) mice were exposed to MWCNTs (1 mg/kg) via oropharyngeal aspiration weekly over four consecutive weeks and evaluated for cellular and pathologic outcomes 11-months post-initial exposure. No lung or pleural tumors were observed in p53(+/+) or p53(+/-) mice exposed to either t- or rMWCNTs. In comparison to tMWCNTs, the rMWCNTs induced the formation of larger granulomas, a greater number of lymphoid aggregates and greater epithelial cell hyperplasia in terminal bronchioles in both p53(+/-) and p53(+/+) mice. A constitutively larger area of CD45R(+)/CD3(+) lymphoid tissue was observed in p53(+/-) mice compared to p53(+/+) mice. Importantly, p53(+/-) mice had larger granulomas induced by rMWCNTs as compared to p53(+/+) mice. These findings indicate that a combination of p53 deficiency and physicochemical characteristics including nanotube geometry are factors in susceptibility to MWCNT-induced lymphoid infiltration and granuloma formation. |
Capillary electrophoresis analysis of affinity to assess carboxylation of multi-walled carbon nanotubes
Davis TA , Patberg SM , Sargent LM , Stefaniak AB , Holland LA . Anal Chim Acta 2018 1027 149-157 Surface oxidation improves the dispersion of carbon nanotubes in aqueous solutions and plays a key role in the development of biosensors, electrochemical detectors and polymer composites. Accurate characterization of the carbon nanotube surface is important because the development of these nano-based applications depends on the degree of functionalization, in particular the amount of carboxylation. Affinity capillary electrophoresis is used to characterize the oxidation of multi-walled carbon nanotubes. A polytryptophan peptide that contains a single arginine residue (WRWWWW) serves as a receptor in affinity capillary electrophoresis to assess the degree of carboxylation. The formation of peptide-nanotube receptor-ligand complex was detected with a UV absorbance detector. Apparent dissociation constants (KD) are obtained by observing the migration shift of the WRWWWW peptide through background electrolyte at increasing concentrations of multi-walled carbon nanotubes. A 20% relative standard deviation in method reproducibility and repeatability is determined with triplicate analysis within a single sample preparation and across multiple sample preparations for a commercially available carbon nanotube. Affinity capillary electrophoresis is applied to assess differences in degree of carboxylation across two manufacturers and to analyze acid treated carbon nanotubes. The results of these studies are compared to X-ray photoelectron spectroscopy and zeta potential. Affinity capillary electrophoresis comparisons of carbon nanotube samples prepared by varying acid treatment time from 30 min to 3 h yielded significant differences in degree of carboxylation. X-ray photoelectron spectroscopy analysis was inconclusive due to potential acid contamination, while zeta potential showed no change based on surface charge. This work is significant to research involving carbon nanotube-based applications because it provides a new metric to rapidly characterize carbon nanotubes obtained from different vendors, or synthesized in laboratories using different procedures. |
In Vivo Toxicity Assessment of Occupational Components of the Carbon Nanotube Life Cycle To Provide Context to Potential Health Effects
Bishop L , Cena L , Orandle M , Yanamala N , Dahm MM , Birch ME , Evans DE , Kodali VK , Eye T , Battelli L , Zeidler-Erdely PC , Casuccio G , Bunker K , Lupoi JS , Lersch TL , Stefaniak AB , Sager T , Afshari A , Schwegler-Berry D , Friend S , Kang J , Siegrist KJ , Mitchell CA , Lowry DT , Kashon ML , Mercer RR , Geraci CL , Schubauer-Berigan MK , Sargent LM , Erdely A . ACS Nano 2017 11 (9) 8849-8863 Pulmonary toxicity studies on carbon nanotubes focus primarily on as-produced materials and rarely are guided by a life cycle perspective or integration with exposure assessment. Understanding toxicity beyond the as-produced, or pure native material, is critical, due to modifications needed to overcome barriers to commercialization of applications. In the first series of studies, the toxicity of as-produced carbon nanotubes and their polymer-coated counterparts was evaluated in reference to exposure assessment, material characterization, and stability of the polymer coating in biological fluids. The second series of studies examined the toxicity of aerosols generated from sanding polymer-coated carbon-nanotube-embedded or neat composites. Postproduction modification by polymer coating did not enhance pulmonary injury, inflammation, and pathology or in vitro genotoxicity of as-produced carbon nanotubes, and for a particular coating, toxicity was significantly attenuated. The aerosols generated from sanding composites embedded with polymer-coated carbon nanotubes contained no evidence of free nanotubes. The percent weight incorporation of polymer-coated carbon nanotubes, 0.15% or 3% by mass, and composite matrix utilized altered the particle size distribution and, in certain circumstances, influenced acute in vivo toxicity. Our study provides perspective that, while the number of workers and consumers increases along the life cycle, toxicity and/or potential for exposure to the as-produced material may greatly diminish. |
Accumulation of ubiquitin and sequestosome-1 implicate protein damage in diacetyl-induced cytotoxicity
Hubbs AF , Fluharty KL , Edwards RJ , Barnabei JL , Grantham JT , Palmer SM , Kelly F , Sargent LM , Reynolds SH , Mercer RR , Goravanahally MP , Kashon ML , Honaker JC , Jackson MC , Cumpston AM , Goldsmith WT , McKinney W , Fedan JS , Battelli LA , Munro T , Bucklew-Moyers W , McKinstry K , Schwegler-Berry D , Friend S , Knepp AK , Smith SL , Sriram K . Am J Pathol 2016 186 (11) 2887-2908 Inhaled diacetyl vapors are associated with flavorings-related lung disease, a potentially fatal airway disease. The reactive alpha-dicarbonyl group in diacetyl causes protein damage in vitro. Dicarbonyl/l-xylulose reductase (DCXR) metabolizes diacetyl into acetoin, which lacks this alpha-dicarbonyl group. To investigate the hypothesis that flavorings-related lung disease is caused by in vivo protein damage, we correlated diacetyl-induced airway damage in mice with immunofluorescence for markers of protein turnover and autophagy. Western immunoblots identified shifts in ubiquitin pools. Diacetyl inhalation caused dose-dependent increases in bronchial epithelial cells with puncta of both total ubiquitin and K63-ubiquitin, central mediators of protein turnover. This response was greater in Dcxr-knockout mice than in wild-type controls inhaling 200 ppm diacetyl, further implicating the alpha-dicarbonyl group in the protein damage. Western immunoblots demonstrated decreased free ubiquitin in airway-enriched fractions. Transmission electron microscopy and colocalization of ubiquitin-positive puncta with lysosomal markers lysosomal-associated membrane protein 1 and 2 and with the multifunctional scaffolding protein sequestosome-1 (SQSTM1/p62) confirmed autophagy. Surprisingly, immunoreactive SQSTM1 also accumulated in the olfactory bulb of the brain. Olfactory bulb SQSTM1 often congregated in activated microglial cells that also contained olfactory marker protein, indicating neuronophagia within the olfactory bulb. This suggests the possibility that SQSTM1 or damaged proteins may be transported from the nose to the brain. Together, these findings strongly implicate widespread protein damage in the etiology of flavorings-related lung disease. |
Evaluating the mechanistic evidence and key data gaps in assessing the potential carcinogenicity of carbon nanotubes and nanofibers in humans
Kuempel ED , Jaurand MC , Moller P , Morimoto Y , Kobayashi N , Pinkerton KE , Sargent LM , Vermeulen RC , Fubini B , Kane AB . Crit Rev Toxicol 2016 47 (1) 1-58 In an evaluation of carbon nanotubes (CNTs) for the IARC Monograph 111, the Mechanisms Subgroup was tasked with assessing the strength of evidence on the potential carcinogenicity of CNTs in humans. The mechanistic evidence was considered to be not strong enough to alter the evaluations based on the animal data. In this paper, we provide an extended, in-depth examination of the in vivo and in vitro experimental studies according to current hypotheses on the carcinogenicity of inhaled particles and fibers. We cite additional studies of CNTs that were not available at the time of the IARC meeting in October 2014, and extend our evaluation to include carbon nanofibers (CNFs). Finally, we identify key data gaps and suggest research needs to reduce uncertainty. The focus of this review is on the cancer risk to workers exposed to airborne CNT or CNF during the production and use of these materials. The findings of this review, in general, affirm those of the original evaluation on the inadequate or limited evidence of carcinogenicity for most types of CNTs and CNFs at this time, and possible carcinogenicity of one type of CNT (MWCNT-7). The key evidence gaps to be filled by research include: investigation of possible associations between in vitro and early-stage in vivo events that may be predictive of lung cancer or mesothelioma, and systematic analysis of dose-response relationships across materials, including evaluation of the influence of physico-chemical properties and experimental factors on the observation of nonmalignant and malignant endpoints. |
Design and methods of the Population Assessment of Tobacco and Health (PATH) Study
Hyland A , Ambrose BK , Conway KP , Borek N , Lambert E , Carusi C , Taylor K , Crosse S , Fong GT , Cummings KM , Abrams D , Pierce JP , Sargent J , Messer K , Bansal-Travers M , Niaura R , Vallone D , Hammond D , Hilmi N , Kwan J , Piesse A , Kalton G , Lohr S , Pharris-Ciurej N , Castleman V , Green VR , Tessman G , Kaufman A , Lawrence C , van Bemmel DM , Kimmel HL , Blount B , Yang L , O'Brien B , Tworek C , Alberding D , Hull LC , Cheng YC , Maklan D , Backinger CL , Compton WM . Tob Control 2016 26 (4) 371-378 BACKGROUND: This paper describes the methods and conceptual framework for Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study data collection. The National Institutes of Health, through the National Institute on Drug Abuse, is partnering with the Food and Drug Administration's (FDA) Center for Tobacco Products to conduct the PATH Study under a contract with Westat. METHODS: The PATH Study is a nationally representative, longitudinal cohort study of 45 971 adults and youth in the USA, aged 12 years and older. Wave 1 was conducted from 12 September 2013 to 15 December 2014 using Audio Computer-Assisted Self-Interviewing to collect information on tobacco-use patterns, risk perceptions and attitudes towards current and newly emerging tobacco products, tobacco initiation, cessation, relapse behaviours and health outcomes. The PATH Study's design allows for the longitudinal assessment of patterns of use of a spectrum of tobacco products, including initiation, cessation, relapse and transitions between products, as well as factors associated with use patterns. Additionally, the PATH Study collects biospecimens from consenting adults aged 18 years and older and measures biomarkers of exposure and potential harm related to tobacco use. CONCLUSIONS: The cumulative, population-based data generated over time by the PATH Study will contribute to the evidence base to inform FDA's regulatory mission under the Family Smoking Prevention and Tobacco Control Act and efforts to reduce the Nation's burden of tobacco-related death and disease. |
Reducing global diabetes burden by implementing solutions and identifying gaps: a Lancet Commission
Chan JC , Gregg EW , Sargent J , Horton R . Lancet 2016 387 (10027) 1494-5 Diabetes is a silent killer that affects men and women, young and old, rich and poor. According to the International Diabetes Federation, in 2016, one in 11 adults has diabetes worldwide, one person dies with diabetes every 6 s, and US$1 in $9 of health-care expenditure is spent on diabetes and its complications.1 More than 80% of people with diabetes live in low-income and middle-income countries, and most of them have type 2 diabetes.1 In many of these places, the rising prevalence in both type 12 and type 2 diabetes highlights the potential effects of rapid urbanisation on health and disease development, especially among individuals with genetic predisposition and underserved communities.3 | Between 1990 and 2000, the rates of diabetes-related comorbidities, such as myocardial infarction, stroke, amputation, end-stage renal disease, and hyperglycaemia crisis, declined in the USA.4 With increased life expectancy and a decline in the prevalence of cardiovascular disease, the burden of other comorbidities, such as renal disease, cancer, frailty, and dementia, is a growing concern.4, 5 However, rigorous epidemiological data on diabetes-related morbidity and cost are limited to only about a dozen countries, leaving the true worldwide impact unclear. Further, the high burden of diabetes among adolescents and young adults in low-income and middle-income countries, partly driven by gestational diabetes and childhood obesity, might be fuelling new cases of premature cardiovascular-renal disease.3 |
Carbon nanotube uptake changes the biomechanical properties of human lung epithelial cells in a time-dependent manner
Dong C , Eldawud R , Sargent LM , Kashon ML , Lowry D , Rojanasakul Y , Zoica Dinu C . J Mater Chem B 2015 3 (19) 3983-3992 The toxicity of engineered nanomaterials in biological systems depends on both the nanomaterial's properties and the exposure duration. Herein we used a multi-tier strategy to investigate the relationship between user-characterized multi-walled carbon nanotubes (MWCNTs) exposure duration and their induced biochemical and biomechanical effects on model human lung epithelial cells (BEAS-2B). Our results showed that exposure to MWCNTs leads to time-dependent intracellular uptake and generation of reactive oxygen species (ROS), along with time-dependent gradual changes in cellular biomechanical properties. In particular, the amount of internalized MWCNTs followed a sigmoidal curve with the majority of the MWCNTs being internalized within 6 h of exposure; further, the sigmoidal uptake correlated with the changes in the oxidative levels and cellular biomechanical properties respectively. Our study provides new insights into the time-dependent induced toxicity caused by exposure to occupationally relevant doses of MWCNTs and could potentially help establish bases for early risk assessments of other nanomaterials' toxicological profiles. |
mRNAs and miRNAs in whole blood associated with lung hyperplasia, fibrosis, and bronchiolo-alveolar adenoma and adenocarcinoma after multi-walled carbon nanotube inhalation exposure in mice
Snyder-Talkington BN , Dong C , Sargent LM , Porter DW , Staska LM , Hubbs AF , Raese R , McKinney W , Chen BT , Battelli L , Lowry DT , Reynolds SH , Castranova V , Qian Y , Guo NL . J Appl Toxicol 2015 36 (1) 161-74 Inhalation exposure to multi-walled carbon nanotubes (MWCNT) in mice results in inflammation, fibrosis and the promotion of lung adenocarcinoma; however, the molecular basis behind these pathologies is unknown. This study determined global mRNA and miRNA profiles in whole blood from mice exposed by inhalation to MWCNT that correlated with the presence of lung hyperplasia, fibrosis, and bronchiolo-alveolar adenoma and adenocarcinoma. Six-week-old, male, B6C3F1 mice received a single intraperitoneal injection of either the DNA-damaging agent methylcholanthrene (MCA, 10 microg g-1 body weight) or vehicle (corn oil). One week after injections, mice were exposed by inhalation to MWCNT (5 mg m-3 , 5 hours per day, 5 days per week) or filtered air (control) for a total of 15 days. At 17 months post-exposure, mice were euthanized and examined for the development of pathological changes in the lung, and whole blood was collected and analyzed using microarray analysis for global mRNA and miRNA expression. Numerous mRNAs and miRNAs in the blood were significantly up- or down-regulated in animals developing pathological changes in the lung after MCA/corn oil administration followed by MWCNT/air inhalation, including fcrl5 and miR-122-5p in the presence of hyperplasia, mthfd2 and miR-206-3p in the presence of fibrosis, fam178a and miR-130a-3p in the presence of bronchiolo-alveolar adenoma, and il7r and miR-210-3p in the presence of bronchiolo-alveolar adenocarcinoma, among others. The changes in miRNA and mRNA expression, and their respective regulatory networks, identified in this study may potentially serve as blood biomarkers for MWCNT-induced lung pathological changes. |
Carcinogenicity of fluoro-edenite, silicon carbide fibres and whiskers, and carbon nanotubes
Grosse Y , Loomis D , Guyton KZ , Lauby-Secretan B , El Ghissassi F , Bouvard V , Benbrahim-Tallaa L , Guha N , Scoccianti C , Mattock H , Straif K , Kane AB , Debia M , Dion C , Moller P , Savolainen K , Canu IG , Jaurand MC , Comba P , Kobayashi N , Morimoto Y , Tsuda H , Yu IJ , Vermeulen R , Bugge MD , Bateson TF , Kuempel ED , Morgan DL , Pinkerton KE , Sargent LM , Stayner L . Lancet Oncol 2014 15 (13) 1427-8 In October, 2014, 21 experts from ten countries met at the International Agency for Research on Cancer (IARC; Lyon, France) to assess the carcinogenicity of fluoro-edenite, silicon carbide (SiC) fibres and whiskers, and carbon nanotubes (CNTs) including single-walled (SWCNTs) and multi-walled (MWCNTs) types. These assessments will be published as Volume 111 of the IARC Monographs.1 | Fluoro-edenite was first identified around the Etna volcano near Biancavilla, Italy; a similar mineral was also reported from the Kimpo volcano in Japan. Fluoro-edenite can occur as asbestiform fibres. Unpaved roads made from local quarry products from Biancavilla, used since the 1950s, are a source for airborne fluoro-edenite fibres; additionally indoor air was also contaminated from the use of the quarry's products in building materials. Several surveillance studies reported an excess of mesothelioma incidence and mortality in the regional population of Biancavilla.2 Since the rate ratios for mesothelioma were large and stable, chance was unlikely to explain these findings. The excess was similar in men and women, and most prominent in young adults, suggesting an environmental rather than occupational cause. Moreover, most of the cases had no history of occupational exposure to asbestos. Fluoro-edenite fibrous amphibole was classified as carcinogenic to humans (Group 1) on the basis of sufficient evidence in humans that exposure to fluoro-edenite causes mesothelioma. Sufficient evidence of carcinogenicity was also reported in experimental animals, with increased incidences of mesotheliomas observed in one study in male and female rats given fibrous fluoro-edenite by intraperitoneal or intrapleural injection.3 The results of the few available mechanistic studies were consistent with proposed mechanisms of fibre carcinogenicity.4 |
Towards elucidating the effects of purified MWCNTs on human lung epithelial cells
Dong C , EIdawud R , Sargent LM , Kashon ML , Lowry D , Rojanasakul Y , Dinu CZ . Environ Sci Nano 2014 1 (6) 95-603 Toxicity of engineered nanomaterials is associated with their inherent properties, both physical and chemical. Recent studies have shown that exposure to multi-walled carbon nanotubes (MWCNTs) promotes tumors and tumor-associated pathologies and lead to carcinogenesis in model in vivo systems. Here in we examined the potential of purified MWCNTs used at occupationally relevant exposure doses for particles not otherwise regulated to affect human lung epithelial cells. The uptake of the purified MWCNTs was evaluated using fluorescence activated cell sorting (FACS), while the effects on cell fate were assessed using 2- (4-iodophenyl) - 3- (4-nitrophenyl) - 5-(2, 4-disulfophenyl) -2H-tetrazolium salt colorimetric assay, cell cycle and nanoindentation. Our results showed that exposure to MWCNTs reduced cell metabolic activity and induced cell cycle arrest. Our analysis further emphasized that MWCNTs-induced cellular fate results from multiple types of interactions that could be analyzed by means of intracellular biomechanical changes and are pivotal in understanding the underlying MWCNTs-induced cell transformation. |
Genotoxicity of multi-walled carbon nanotubes at occupationally relevant doses
Siegrist KJ , Reynolds SH , Kashon ML , Lowry DT , Dong C , Hubbs AF , Young SH , Salisbury JL , Porter DW , Benkovic SA , McCawley M , Keane MJ , Mastovich JT , Bunker KL , Cena LG , Sparrow MC , Sturgeon JL , Dinu CZ , Sargent LM . Part Fibre Toxicol 2014 11 6 ![]() Carbon nanotubes are commercially-important products of nanotechnology; however, their low density and small size makes carbon nanotube respiratory exposures likely during their production or processing. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to single-walled carbon nanotubes (SWCNT). In this study, we examined whether multi-walled carbon nanotubes (MWCNT) cause mitotic spindle damage in cultured cells at doses equivalent to 34 years of exposure at the NIOSH Recommended Exposure Limit (REL). MWCNT induced a dose responsive increase in disrupted centrosomes, abnormal mitotic spindles and aneuploid chromosome number 24 hours after exposure to 0.024, 0.24, 2.4 and 24 mug/cm(2) MWCNT. Monopolar mitotic spindles comprised 95% of disrupted mitoses. Three-dimensional reconstructions of 0.1 mum optical sections showed carbon nanotubes integrated with microtubules, DNA and within the centrosome structure. Cell cycle analysis demonstrated a greater number of cells in S-phase and fewer cells in the G2 phase in MWCNT-treated compared to diluent control, indicating a G1/S block in the cell cycle. The monopolar phenotype of the disrupted mitotic spindles and the G1/S block in the cell cycle is in sharp contrast to the multi-polar spindle and G2 block in the cell cycle previously observed following exposure to SWCNT. One month following exposure to MWCNT there was a dramatic increase in both size and number of colonies compared to diluent control cultures, indicating a potential to pass the genetic damage to daughter cells. Our results demonstrate significant disruption of the mitotic spindle by MWCNT at occupationally relevant exposure levels. |
Promotion of lung adenocarcinoma following inhalation exposure to multi-walled carbon nanotubes
Sargent LM , Porter DW , Staska LM , Hubbs AF , Lowry DT , Battelli L , Siegrist KJ , Kashon ML , Mercer RR , Bauer AK , Chen BT , Salisbury JL , Frazer D , McKinney W , Andrew M , Tsuruoka S , Endo M , Fluharty KL , Castranova V , Reynolds SH . Part Fibre Toxicol 2014 11 (1) 3 BACKGROUND: Engineered carbon nanotubes are currently used in many consumer and industrial products such as paints, sunscreens, cosmetics, toiletries, electronic processes and industrial lubricants. Carbon nanotubes are among the more widely used nanoparticles and come in two major commercial forms, single-walled carbon nanotubes (SWCNT) and the more rigid, multi-walled carbon nanotubes (MWCNT). The low density and small size of these particles makes respiratory exposures likely. Many of the potential health hazards have not been investigated, including their potential for carcinogenicity. We, therefore, utilized a two stage initiation/promotion protocol to determine whether inhaled MWCNT act as a complete carcinogen and/or promote the growth of cells with existing DNA damage. Six week old, male, B6C3F1 mice received a single intraperitoneal (ip) injection of either the initiator methylcholanthrene(MCA, 10 mug/g BW, i.p.), or vehicle (corn oil). One week after i.p. injections, mice were exposed by inhalation to MWCNT (5 mg/m3, 5 hours/day, 5 days/week) or filtered air (controls) for a total of 15 days. At 17 months post-exposure, mice were euthanized and examined for lung tumor formation. RESULTS: Twenty-three percent of the filtered air controls, 26.5% of the MWCNT-exposed, and 51.9% of the MCA-exposed mice, had lung bronchiolo-alveolar adenomas and lung adenocarcinomas. The average number of tumors per mouse was 0.25, 0.81 and 0.38 respectively. By contrast, 90.5% of the mice which received MCA followed by MWCNT had bronchiolo-alveolar adenomas and adenocarcinomas with an average of 2.9 tumors per mouse 17months after exposure. Indeed, 62% of the mice exposed to MCA followed by MWCNT had bronchiolo-alveolar adenocarcinomas compared to 13% of the mice that received filtered air, 22% of the MCA-exposed, or 14% of the MWCNT-exposed. Mice with early morbidity resulting in euthanasia had the highest rate of metastatic disease. Three mice exposed to both MCA and MWCNT that were euthanized early had lung adenocarcinoma with evidence of metastasis (5.5%). Five mice (9%) exposed to MCA and MWCNT and 1 (1.6%) exposed to MCA developed serosal tumors morphologically consistent with sarcomatous mesotheliomas, whereas mice administered MWCNT or air alone did not develop similar neoplasms. CONCLUSIONS: These data demonstrate that some MWCNT exposures promote the growth and neoplastic progression of initiated lung cells in B6C3F1 mice. In this study, the mouse MWCNT lung burden of 31.2 mug/mouse approximates feasible human occupational exposures. Therefore, the results of this study indicate that caution should be used to limit human exposures to MWCNT. |
Exposure to carbon nanotubes leads to changes in the cellular biomechanics
Dong C , Kashon ML , Lowry D , Dordick JS , Reynolds SH , Rojanasakul Y , Sargent LM , Dinu CZ . Adv Healthc Mater 2013 2 (7) 945-51 ![]() Exposure to carbon nanotubes induces significant changes in cellular biomechanics. Using nanoindentation, it is observed that the exposed cells have significantly higher stiffness when compared to controls, especially at the nuclear region, and significant increases in surface area. |
Nanotechnology: toxicologic pathology
Hubbs AF , Sargent LM , Porter DW , Sager TM , Chen BT , Frazer DG , Castranova V , Sriram K , Nurkiewicz TR , Reynolds SH , Battelli LA , Schwegler-Berry D , McKinney W , Fluharty KL , Mercer RR . Toxicol Pathol 2013 41 (2) 395-409 Nanotechnology involves technology, science, and engineering in dimensions less than 100 nm. A virtually infinite number of potential nanoscale products can be produced from many different molecules and their combinations. The exponentially increasing number of nanoscale products will solve critical needs in engineering, science, and medicine. However, the virtually infinite number of potential nanotechnology products is a challenge for toxicologic pathologists. Because of their size, nanoparticulates can have therapeutic and toxic effects distinct from micron-sized particulates of the same composition. In the nanoscale, distinct intercellular and intracellular translocation pathways may provide a different distribution than that obtained by micron-sized particulates. Nanoparticulates interact with subcellular structures including microtubules, actin filaments, centrosomes, and chromatin; interactions that may be facilitated in the nanoscale. Features that distinguish nanoparticulates from fine particulates include increased surface area per unit mass and quantum effects. In addition, some nanotechnology products, including the fullerenes, have a novel and reactive surface. Augmented microscopic procedures including enhanced dark-field imaging, immunofluorescence, field-emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy are useful when evaluating nanoparticulate toxicologic pathology. Thus, the pathology assessment is facilitated by understanding the unique features at the nanoscale and the tools that can assist in evaluating nanotoxicology studies. |
Single-walled carbon nanotube-induced mitotic disruption.
Sargent LM , Hubbs AF , Young SH , Kashon ML , Dinu CZ , Salisbury JL , Benkovic SA , Lowry DT , Murray AR , Kisin ER , Siegrist KJ , Battelli L , Mastovich J , Sturgeon JL , Bunker KL , Shvedova AA , Reynolds SH . Mutat Res 2011 745 28-37 ![]() Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96mcg/cm(2) single-walled carbon nanotubes (SWCNT). To investigate mitotic spindle aberrations at concentrations anticipated in exposed workers, primary and immortalized human airway epithelial cells were exposed to SWCNT for 24-72h at doses equivalent to 20 weeks of exposure at the Permissible Exposure Limit for particulates not otherwise regulated. We have now demonstrated fragmented centrosomes, disrupted mitotic spindles and aneuploid chromosome number at those doses. The data further demonstrated multipolar mitotic spindles comprised 95% of the disrupted mitoses. The increased multipolar mitotic spindles were associated with an increased number of cells in the G2 phase of mitosis, indicating a mitotic checkpoint response. Nanotubes were observed in association with mitotic spindle microtubules, the centrosomes and condensed chromatin in cells exposed to 0.024, 0.24, 2.4 and 24mcg/cm(2) SWCNT. Three-dimensional reconstructions showed carbon nanotubes within the centrosome structure. The lower doses did not cause cytotoxicity or reduction in colony formation after 24h; however, after three days, significant cytotoxicity was observed in the SWCNT-exposed cells. Colony formation assays showed an increased proliferation seven days after exposure. Our results show significant disruption of the mitotic spindle by SWCNT at occupationally relevant doses. The increased proliferation that was observed in carbon nanotube-exposed cells indicates a greater potential to pass the genetic damage to daughter cells. Disruption of the centrosome is common in many solid tumors including lung cancer. The resulting aneuploidy is an early event in the progression of many cancers, suggesting that it may play a role in both tumorigenesis and tumor progression. These results suggest caution should be used in the handling and processing of carbon nanotubes. |
Digitoxin and a synthetic monosaccharide analog inhibit cell viability in lung cancer cells
Elbaz HA , Stueckle TA , Wang HY , O'Doherty G , Lowry DT , Sargent LM , Wang L , Dinu CZ , Rojanasakul Y . Toxicol Appl Pharmacol 2011 258 (1) 51-60 Mechanisms of digitoxin-inhibited cell growth and induced apoptosis in human non-small cell lung cancer (NCI-H460) cells remain unclear. Understanding how digitoxin or derivate analogs induce their cytotoxic effect below therapeutically relevant concentrations will help in designing and developing novel, safer and more effective anti-cancer drugs. In this study, NCI-H460 cells were treated with digitoxin and a synthetic analog D6-MA to determine their anti-cancer activity. Different concentrations of digitoxin and D6-MA were used and the subsequent changes in cell morphology, viability, cell cycle, and protein expressions were determined. Digitoxin and D6-MA induced dose-dependent apoptotic morphologic changes in NCI-H460 cells via caspase-9 cleavage, with D6-MA possessing 5-fold greater potency than digitoxin. In comparison, non-tumorigenic immortalized bronchial and small airway epithelial cells displayed significantly less apoptotic sensitivity compared to NCI-H460 cells suggesting that both digitoxin and D6-MA were selective for NSCLC. Furthermore, NCI-H460 cells arrested in G(2)/M phase following digitoxin and D6-MA treatment. Post-treatment evaluation of key G2/M checkpoint regulatory proteins identified down-regulation of cyclin B1/cdc2 complex and survivin. Additionally, Chk1/2 and p53 related proteins experienced down-regulation suggesting a p53-independent cell cycle arrest mechanism. In summary, digitoxin and D6-MA exert anti-cancer effects on NCI-H460 cells through apoptosis or cell cycle arrest, with D6-MA showing at least 5-fold greater potency relative to digitoxin. |
Microscale exoglycosidase processing and lectin capture of glycans with phospholipid assisted capillary electrophoresis separations
Archer-Hartmann SA , Sargent LM , Lowry DT , Holland LA . Anal Chem 2011 83 (7) 2740-7 Capillary electrophoresis separations of glycans labeled with 1-aminopyrene-3,6,8-trisulfonic acid were achieved with separation efficiencies ranging from 480,000 to 640,000 theoretical plates in a 60.2 cm, 25 micrometer inner diameter fused silica capillary. Under these separation conditions, the coefficient of variation in peak area is 10%, and if labeling efficiency is estimated at 100%, the limit of detection is 15 fM. The capillary electrophoresis method incorporated phospholipid additives to enhance the separation of glycans with slight differences in hydrodynamic volume. In addition, the phospholipid additives supported the integration of the lectin concanavalin A as well as the enzymes alpha1-2,3 mannosidase or beta1-4 galactosidase to provide structural and compositional information about the glycans subject to separation. The use of in-capillary cleavage of terminal glycan residues with exoglycosidases offers a number of advantages over benchtop enzymatic sequencing, including reduced consumption of analyte, as well as enzyme. These methods were used to evaluate glycans derived from the glycoproteins alpha1-acid glycoprotein, fetuin, and ribonuclease B, as well as from glycoproteins collected from MCF7 cells. |
Nanotoxicology--a pathologist's perspective
Hubbs AF , Mercer RR , Benkovic SA , Harkema J , Sriram K , Schwegler-Berry D , Goravanahally MP , Nurkiewicz TR , Castranova V , Sargent LM . Toxicol Pathol 2011 39 (2) 301-24 Advances in chemistry and engineering have created a new technology, nanotechnology, involving the tiniest known manufactured products. These products have a rapidly increasing market share and appear poised to revolutionize engineering, cosmetics, and medicine. Unfortunately, nanotoxicology, the study of nanoparticulate health effects, lags behind advances in nanotechnology. Over the past decade, existing literature on ultrafine particles and respirable durable fibers has been supplemented by studies of first-generation nanotechnology products. These studies suggest that nanosizing increases the toxicity of many particulates. First, as size decreases, surface area increases, thereby speeding up dissolution of soluble particulates and exposing more of the reactive surface of durable but reactive particulates. Second, nanosizing facilitates movement of particulates across cellular and intracellular barriers. Third, nanosizing allows particulates to interact with, and sometimes even hybridize with, subcellular structures, including in some cases microtubules and DNA. Finally, nanosizing of some particulates, increases pathologic and physiologic responses, including inflammation, fibrosis, allergic responses, genotoxicity, and carcinogenicity, and may alter cardiovascular and lymphatic function. Knowing how the size and physiochemical properties of nanoparticulates affect bioactivity is important in assuring that the exciting new products of nanotechnology are used safely. This review provides an introduction to the pathology and toxicology of nanoparticulates. |
Genotoxicity of carbon nanofibers: are they potentially more or less dangerous than carbon nanotubes or asbestos?
Kisin ER , Murray AR , Sargent L , Lowry D , Chirila M , Siegrist KJ , Schwegler-Berry D , Leonard S , Castranova V , Fadeel B , Kagan VE , Shvedova AA . Toxicol Appl Pharmacol 2011 252 (1) 1-10 ![]() The production of carbon nanofibers and nanotubes (CNF/CNT) and their composite products is increasing globally. CNF are generating great interest in industrial sectors such as energy production and electronics, where alternative materials may have limited performance or are produced at a much higher cost. However, despite the increasing industrial use of carbon nanofibers, information on their potential adverse health effects is limited. In the current study, we examine the cytotoxic and genotoxic potential of carbon-based nanofibers (Pyrograf ((R))-III) and compare this material with the effects of asbestos fibers (crocidolite) or single-walled carbon nanotubes (SWCNT). The genotoxic effects in the lung fibroblast (V79) cell line were examined using two complementary assays: the comet assay and micronucleus (MN) test. In addition, we utilized fluorescence in situ hybridization to detect the chromatin pan-centromeric signals within the MN indicating their origin by aneugenic (chromosomal malsegregation) or clastogenic (chromosome breakage) mechanisms. Cytotoxicity tests revealed a concentration- and time-dependent loss of V79 cell viability after exposure to all tested materials in the following sequence: asbestos>CNF>SWCNT. Additionally, cellular uptake and generation of oxygen radicals was seen in the murine RAW264.7 macrophages following exposure to CNF or asbestos but not after administration of SWCNT. DNA damage and MN induction were found after exposure to all tested materials with the strongest effect seen for CNF. Finally, we demonstrated that CNF induced predominately centromere-positive MN in primary human small airway epithelial cells (SAEC) indicating aneugenic events. Further investigations are warranted to elucidate the possible mechanisms involved in CNF-induced genotoxicity. |
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