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Publication
Journal: ChemSusChem
March/31/2010
Abstract
5-hydroxymethyl-2-furfural is selectively converted into 2,5-furandicarboxylic acid (99 mol % yield) in water, under mild conditions (65-130 degrees C, 10 bar air) with gold nanoparticles supported on nanoparticulate ceria (Au-CeO(2)) and on titania (Au-TiO(2)); the former being more active and selective. A reaction mechanism is established and the rate-limiting step of the reaction is the alcohol oxidation of 5-hydroxymethyl-2-furancarboxylic acid into 2,5-furandicarboxylic acid. The effects of pressure, temperature, substrate-to-catalyst ratio, and amount of base are studied to find the most suitable reaction conditions. The absence of metal leaching is verified by chemical analysis of the reaction solution and by confirming that the reaction does not occur after catalyst removal by filtration in hot water. Substrate degradation is strongly diminished and the catalyst life increased by performing the reaction in two temperature steps.
Publication
Journal: Environmental Research
June/25/2012
Abstract
BACKGROUND
Cerium oxide (CeO(2)) nanoparticles improve the burning efficiency of fuel, however, little is known about health impacts of altered emissions from the vehicles.
METHODS
Atherosclerosis-prone apolipoprotein E knockout (ApoE(-/-)) mice were exposed by inhalation to diluted exhaust (1.7 mg/m(3), 20, 60 or 180 min, 5 day/week, for 4 weeks), from an engine using standard diesel fuel (DE) or the same diesel fuel containing 9 ppm cerium oxide nanoparticles (DCeE). Changes in hematological indices, clinical chemistry, atherosclerotic burden, tissue levels of inflammatory cytokines and pathology of the major organs were assessed.
RESULTS
Addition of CeO(2) to fuel resulted in a reduction of the number (30%) and surface area (10%) of the particles in the exhaust, whereas the gaseous co-pollutants were increased (6-8%). There was, however, a trend towards an increased size and complexity of the atherosclerotic plaques following DE exposure, which was not evident in the DCeE group. There were no clear signs of altered hematological or pathological changes induced by either treatment. However, levels of proinflammatory cytokines were modulated in a brain region and liver following DCeE exposure.
CONCLUSIONS
These results imply that addition of CeO(2) nanoparticles to fuel decreases the number of particles in exhaust and may reduce atherosclerotic burden associated with exposure to standard diesel fuel. From the extensive assessment of biological parameters performed, the only concerning effect of cerium addition was a slightly raised level of cytokines in a region of the central nervous system. Overall, the use of cerium as a fuel additive may be a potentially useful way to limit the health effects of vehicle exhaust. However, further testing is required to ensure that such an approach is not associated with a chronic inflammatory response which may eventually cause long-term health effects.
Publication
Journal: Journal of the American Chemical Society
August/31/2010
Abstract
CeO(2) is a catalytic material of exceptional technological importance, and the precise role of oxygen vacancies is crucial to the greater understanding of these oxide materials. In this work, two ceria nanorod samples with different types and distributions of oxygen vacancies were synthesized. A direct relationship between the concentration of the larger size oxygen vacancy clusters and the reducibility/reactivity of nanosized ceria was revealed. These results may be an important step in understanding and designing active sites at the surface of metal oxide catalytic materials.
Publication
Journal: Nanotechnology
March/8/2010
Abstract
There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO(2)) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 microg ml(-1) of CeO(2) nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.
Publication
Journal: Science of the Total Environment
August/8/2001
Abstract
Vinyl chloride (VC) is a trans-species carcinogen, producing tumors in a variety of tissues, from both inhalation and oral exposures, across a number of species. In particular, exposure to VC has been associated with a rare tumor, liver angiosarcoma, in a large number of studies in mice, rats, and humans. The mode of action for the carcinogenicity of VC appears to be a relatively straightforward example of DNA adduct formation by a reactive metabolite, leading to mutation, mistranscription, and neoplasia. The objective of the present analysis was to investigate the comparative potency of a classic genotoxic carcinogen across species, by performing a quantitative comparison of the carcinogenic potency of VC using data from inhalation and oral rodent bioassays as well as from human epidemiological studies. A physiologically-based pharmacokinetic (PBPK) model for VC was developed to support the target tissue dosimetry for the cancer risk assessment. Unlike previous models, the initial metabolism of VC was described as occurring via two saturable pathways, one representing low capacity-high affinity oxidation by CYP2E1 and the other (in the rodent) representing higher capacity-lower affinity oxidation by other isozymes of P450, producing in both cases chloroethylene oxide (CEO) and chloroacetaldehyde (CAA) as intermediate reactive products. Depletion of glutathione by reaction with CEO and CAA was also described. Animal-based risk estimates for human inhalation exposure to VC using total metabolism estimates from the PBPK model were consistent with risk estimates based on human epidemiological data, and were lower than those currently used in environmental decision-making by a factor of 80.
Publication
Journal: Implementation Science
December/30/2013
Abstract
BACKGROUND
Improving quality in children's mental health and social service settings will require implementation strategies capable of moving effective treatments and other innovations (e.g., assessment tools) into routine care. It is likely that efforts to identify, develop, and refine implementation strategies will be more successful if they are informed by relevant stakeholders and are responsive to the strengths and limitations of the contexts and implementation processes identified in usual care settings. This study will describe: the types of implementation strategies used; how organizational leaders make decisions about what to implement and how to approach the implementation process; organizational stakeholders' perceptions of different implementation strategies; and the potential influence of organizational culture and climate on implementation strategy selection, implementation decision-making, and stakeholders' perceptions of implementation strategies.
METHODS
This study is a mixed methods multiple case study of seven children's social service organizations in one Midwestern city in the United States that compose the control group of a larger randomized controlled trial. Qualitative data will include semi-structured interviews with organizational leaders (e.g., CEOs/directors, clinical directors, program managers) and a review of documents (e.g., implementation and quality improvement plans, program manuals, etc.) that will shed light on implementation decision-making and specific implementation strategies that are used to implement new programs and practices. Additionally, focus groups with clinicians will explore their perceptions of a range of implementation strategies. This qualitative work will inform the development of a Web-based survey that will assess the perceived effectiveness, relative importance, acceptability, feasibility, and appropriateness of implementation strategies from the perspective of both clinicians and organizational leaders. Finally, the Organizational Social Context measure will be used to assess organizational culture and climate. Qualitative, quantitative, and mixed methods data will be analyzed and interpreted at the case level as well as across cases in order to highlight meaningful similarities, differences, and site-specific experiences.
CONCLUSIONS
This study is designed to inform efforts to develop more effective implementation strategies by fully describing the implementation experiences of a sample of community-based organizations that provide mental health services to youth in one Midwestern city.
Publication
Journal: Academic Medicine
August/23/2006
Abstract
Identification of the drivers of change that hasten improvement of chronic illness care in resident practices serves as an effective strategy for transformative change. The Academic Chronic Care Collaborative (ACCC) is an ongoing network of 48 teams from 22 teaching hospitals and systems that have committed to implementation of the evidence-based Chronic Care Model in their residency practices. The teams track the results of their efforts by monthly reports of both clinical and educational outcomes. The authors' experience with these self-selected teams shows that the two most effective drivers of change have been organization-wide leadership -- from the CEO to the clinical manager -- and the academic culture, e.g., competitiveness, the aspiration for excellence, focus on the research mission, comfort with data, and commitment to the education mission. These ACCC teams and their sponsoring health systems have successfully harnessed these drivers for the implementation of evidence-based chronic illness care in resident practices.
Publication
Journal: Biology of Reproduction
December/6/1989
Abstract
Experiments were carried out to determine the specificity of growth factor action on maturation of the oocyte-cumulus cell complex in vitro. Cumulus cell-enclosed oocytes (CEO) from primed mice were maintained in meiotic arrest in vitro with hypoxanthine (HX) and treated with one of ten different growth-promoting factors. The percentage of germinal vesicle breakdown (GVB) in the HX controls ranged from 44 to 64.7% after 21-22 h. Oocytes responded to treatment with growth-promoting factors in one of three ways: (1) no response; (2) low response; or (3) high response. The nonresponding groups included transforming growth factor-beta, platelet-derived growth factor, bombesin, sodium orthovanadate, nerve growth factor, and insulin-like growth factors I and II, each of which had no statistically significant effect on GVB. Insulin and fibroblast growth factor were members of the low response group and stimulated increases in GVB of 21.2 24.9%. Epidermal growth factor (EGF) was the only factor that produced a high frequency of maturation in the CEO; 100% of the arrested CEO were stimulated to undergo GVB in response to EGF treatment (a 51% increase over controls). No interaction was observed when EGF was tested with follicle-stimulating hormone (FSH) on hormone-induced GVB. When tested for an action on cumulus cell expansion, EGF was the only growth-promoting factor that triggered this response and did so more effectively than FSH. Heparin suppressed cumulus expansion in both EGF- and FSH-treated CEO, but did not prevent GVB stimulated by either hormone.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors
Publication
Journal: Journal of Pediatrics
December/3/1996
Abstract
OBJECTIVE
To assess the incidence of microdeletions of chromosomal region 22q11 in a population of infants coming to a regional pediatric cardiac center with selected abnormalities of the ventricular outflow tracts and aortic arch and, further, to provide phenotypic/genetic correlations to determine whether patients with 22q11 deletions can be clinically recognized in infancy.
BACKGROUND
DiGeorge syndrome and velocardiofacial syndrome are frequently associated with malformations of the ventricular outflow tracts and aortic arch. Both are usually caused by microdeletions of chromosomal region 22q11. The overall importance of such deletions as a cause of these cardiac malformations remains to be established.
METHODS
All infants with the candidate cardiac phenotypes during a 34-month period were studied. Dysmorphic features, type of cardiac defect, serum calcium concentration, and thymic status were recorded. Cytogenetic studies, including high-resolution karyotyping and fluorescence in situ hybridization using cosmids (cEO or cH748) from the DiGeorge critical region, were performed after clinical assessment.
RESULTS
Fifty infants (including 36 with tetralogy of Fallot with or without pulmonary atresia) were seen during the study period. Twenty-six infants (52%) were dysmorphic, including 19 who were considered to have a phenotypic appearance consistent with 22q11 deletion. Genetic analysis confirmed hemizygosity for 22q11 in 8 of these 19 cases. Results of fluorescence in situ hybridization studies were normal in 22 infants without dysmorphic features and in 5 infants with dysmorphic features not suggestive of a 22q11 deletion.
CONCLUSIONS
Microdeletions of chromosomal region 22q11 are an important cause of selected malformations of the ventricular outflow tracts and aortic arch and account for about 15% to 20% of cases. These deletions may be clinically recognized in early infancy and can be rapidly confirmed by fluorescence in situ hybridization.
Publication
Journal: Global Public Health
April/30/2012
Abstract
Despite recent focus on health systems strengthening, few studies report large-scale efforts to improve hospital management capacity in low-income countries, a central component of improving health care delivery. We sought to assess the contributions of a systems-based approach, the Ethiopian Hospital Management Initiative (EHMI), which established hospital chief executive officers (CEOs) trained through a Masters of Healthcare and Hospital Administration (MHA) degree programme in Ethiopia. We conducted a pre-post study of 24 hospitals that are managed by CEOs in the MHA programme. We measured changes in hospital functioning based on adherence to a set of 86 hospital performance standards across 12 management domains published in the Standards for Hospital Management in Ethiopia. We found that adherence to hospital performance standards increased significantly during the one-year follow-up (27% compared with 51% of standards met at baseline and follow-up, respectively; P-value < 0.001); overall improvement was driven by improvement in seven of the 12 management domains. The EHMI is an example of health systems strengthening with focus on building hospital management capacity. Early evidence suggests that the establishment of hospital CEOs and MHA training to equip them with management skills may promote scalable improvements in health facility functioning.
Publication
Journal: Biology of Reproduction
June/25/1990
Abstract
We have used carbohydrate-binding proteins, or lectins, as tools to investigate the physiological phenomena associated with the preovulatory maturation of the oocyte-cumulus cell complex. Certain lectins are mitogens, and since other mitogenic agents such as growth factors are known to stimulate meiotic maturation and cumulus expansion, we tested the ability of lectins to provoke these physiological responses. Cumulus cell-enclosed oocytes (CEO) from primed mice were maintained in meiotic arrest in vitro with dibutyryl cyclic adenosine 3',5'-monophosphate (dbcAMP) and treated with one of eleven different lectins. With the exception of pokeweed mitogen (PWM), all of the mitogenic lectins tested were able to induce germinal vesicle breakdown (GVB) in meiotically arrested oocytes, and this action required the presence of the somatic cumulus cells; in fact, either there was no effect or maturation was suppressed when cumulus cell-free oocytes (denuded oocytes; DO) were treated with lectins. None of the nonmitogenic lectins stimulated meiotic maturation in either CEO or DO. The mitogenic lectin concanavalin A (Con A) also induced maturation in CEO when meiotic arrest was maintained with hypoxanthine, guanosine, or 3-isobutyl-1-methylxanthine. The kinetics of spontaneous oocyte maturation in inhibitor-free medium were not altered by Con A. Only the mitogenic lectins that induced meiotic maturation stimulated cumulus expansion, with Con A the most active lectin. The actions of Con A on the maturation of the oocyte-cumulus cell complex were inhibited by methyl-alpha-D-mannopyranoside as predicted by its sugar-binding specificity. These results demonstrate that (1) lectins can stimulate maturation of the mouse oocyte-cumulus cell complex; (2) mitogenicity is associated with the positive activity of the lectins; and (3) cumulus cells mediate the stimulatory action of lectins on oocyte maturation, while inhibition of GVB occurs at the oocyte level. These data support the idea that common signals mediate the mitogenic and maturation-inducing actions of lectins.
Publication
Journal: International Journal of Biological Macromolecules
October/12/2016
Abstract
In recent years, the unparalleled and functional properties of essential oils have been extensively reported, but the sensitivity of essential oils to environmental factors and their poor aqueous solubility have limited their applications in industries. Hence, we encapsulated CEO in chitosan nanoparticles by an emulsion-ionic gelation with pantasodium tripolyphosphate (TPP) and sodium hexametaphosphte (HMP), separately, as crosslinkers. The nanoparticles were analyzed by Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation efficiency (EE) and loading capacity (LC) of CEO in chitosan nanoparticles increased with the increase of initial CEO amount. The nanoparticles displayed an average size of 30-80nm with a spherical shape and regular distribution. In vitro release profiles exhibited an initial burst release and followed by a sustained CEO release at different pH conditions. The amount of CEO release from chitosan nanoparticles was higher in acidic pH to basic or neutral pH, respectively. The biological properties of CEO, before and after the encapsulation process were evaluated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and agar disk diffusion method, respectively. The results indicated the encapsulation of CEO in chitosan nanoparticles could be protected the quality.
Publication
Journal: Metallomics
January/22/2013
Abstract
Sustainable development of nanotechnology requires an understanding of the long term ecotoxicological impact of engineered nanomaterials on the environment. Cerium oxide nanoparticles (CeO₂-NPs) have great potential to accumulate and adversely affect the environment owing to their widespread applications in commercial products. This study documented the chronic phenotypic response of tomato plants to CeO₂-NPs (0.1-10 mg L⁻¹) and determined the effect of CeO₂-NPs on tomato yield. The results indicated that CeO₂-NPs at the concentrations applied in this study had either an inconsequential or a slightly positive effect on plant growth and tomato production. However, elevated cerium content was detected in plant tissues exposed to CeO₂-NPs, suggesting that CeO₂-NPs were taken up by tomato roots and translocated to shoots and edible tissues. In particular, substantially higher Ce concentrations were detected in the fruits exposed to 10 mg L⁻¹ CeO₂-NPs, compared with controls. This study sheds light on the long term impact of CeO₂-NPs on plant health and its implications for our food safety and security.
Publication
Journal: Journal of Hazardous Materials
January/22/2012
Abstract
The fate and behavior of nanomaterials (NMs) in environmental media has important consequences for toxicity. The majority of aquatic research to date has focused on NM behavior in freshwater systems. However, pH and salinity differences of seawater affect dissolution and aggregation of NMs. In this study, physical characteristics of metal oxide NMs in seawater were linked with their toxicity to developing sea urchins. The metal oxide NMs TiO(2) and CeO(2) up to 10mg/L were not toxic to the embryos of the white sea urchin (Lytechinus pictus). In contrast, ZnO NM was highly toxic to these embryos (EC(50) = 99.5 μg/L). The toxicity of ZnO NM was not significantly different from bulk ZnO or soluble Zn(2+) (from ZnSO(4) · 7H(2)O), suggesting that the toxicity of ZnO NM can be attributed to soluble Zn(2+). Furthermore, solubility data indicate that at the concentrations used in our sea urchin embryo experiments, ZnO NM was rapidly and completely solubilized in seawater. The present study also demonstrated that Fe-doped NMs were less soluble in seawater compared to pure ZnO NMs, but there was no concomitant reduction in toxicity.
Publication
Journal: Scientific Reports
March/14/2017
Abstract
PM2.5 is the main particulate air pollutant whose aerodynamic diameter is less than 2.5 micron. The inflammation of various respiratory diseases are associated with PM2.5 inhalation. Pro-inflammatory cytokine IL-1β generated from effected cells usually plays a crucial role in many kinds of lung inflammatory reactions. The exacerbation of Th immune responses are identified in some PM2.5 related diseases. To elucidate the underlying mechanism of PM2.5-induced acute lung inflammation, we exposed Balb/c mice to PM2.5 intratracheally and established a mice model. Acute lung inflammation and increased IL-1β expression was observed after PM2.5 instillation. Regulatory factors of IL-1β (TLR4/MyD88 signaling pathway and NLRP3 inflammasome) participated in this lung inflammatory response as well. Treatment with compound essential oils (CEOs) substantially attenuated PM2.5-induced acute lung inflammation. The decreased IL-1β and Th immune responses after CEOs treatment were significant. PM2.5 may increase the secretion of IL-1β through TLR4/MyD88 and NLRP3 pathway resulting in murine airway inflammation. CEOs could attenuate the lung inflammation by reducing IL-1β and Th immune responses in this model. This study describes a potentially important mechanism of PM2.5-induced acute lung inflammation and that may bring about novel therapies for the inflammatory diseases associated with PM2.5 inhalation.
Publication
Journal: Oncologist
April/10/2016
Abstract
BACKGROUND
In this paper, we provide background and context regarding the potential for a new data-sharing platform, the Project Data Sphere (PDS) initiative, funded by financial and in-kind contributions from the CEO Roundtable on Cancer, to transform cancer research and improve patient outcomes. Given the relatively modest decline in cancer death rates over the past several years, a new research paradigm is needed to accelerate therapeutic approaches for oncologic diseases. Phase III clinical trials generate large volumes of potentially usable information, often on hundreds of patients, including patients treated with standard of care therapies (i.e., controls). Both nationally and internationally, a variety of stakeholders have pursued data-sharing efforts to make individual patient-level clinical trial data available to the scientific research community.
UNASSIGNED
For researchers, shared data have the potential to foster a more collaborative environment, to answer research questions in a shorter time frame than traditional randomized control trials, to reduce duplication of effort, and to improve efficiency. For industry participants, use of trial data to answer additional clinical questions could increase research and development efficiency and guide future projects through validation of surrogate end points, development of prognostic or predictive models, selection of patients for phase II trials, stratification in phase III studies, and identification of patient subgroups for development of novel therapies. Data transparency also helps promote a public image of collaboration and altruism among industry participants. For patient participants, data sharing maximizes their contribution to public health and increases access to information that may be used to develop better treatments. Concerns about data-sharing efforts include protection of patient privacy and confidentiality. To alleviate these concerns, data sets are deidentified to maintain anonymity. To address industry concerns about protection of intellectual property and competitiveness, we illustrate several models for data sharing with varying levels of access to the data and varying relationships between trial sponsors and data access sponsors.
UNASSIGNED
PDS is an independent initiative of the CEO Roundtable on Cancer Life Sciences Consortium, built to voluntarily share, integrate, and analyze comparator arms of historical cancer clinical trial data sets to advance future cancer research. The aim is to provide a neutral, broad-access platform for industry and academia to share raw, deidentified data from late-phase oncology clinical trials using comparator-arm data sets. These data are likely to be hypothesis generating or hypothesis confirming but, notably, do not take the place of performing a well-designed trial to address a specific hypothesis. Prospective providers of data to PDS complete and sign a data sharing agreement that includes a description of the data they propose to upload, and then they follow easy instructions on the website for uploading their deidentified data. The SAS Institute has also collaborated with the initiative to provide intrinsic analytic tools accessible within the website itself. As of October 2014, the PDS website has available data from 14 cancer clinical trials covering 9,000 subjects, with hopes to further expand the database to include more than 25,000 subject accruals within the next year. PDS differentiates itself from other data-sharing initiatives by its degree of openness, requiring submission of only a brief application with background information of the individual requesting access and agreement to terms of use. Data from several different sponsors may be pooled to develop a comprehensive cohort for analysis. In order to protect patient privacy, data providers in the U.S. are responsible for deidentifying data according to standards set forth by the Privacy Rule of the U.S. Health Insurance Portability and Accountability Act of 1996. USING DATA SHARING TO IMPROVE OUTCOMES IN CANCER THE "PROSTATE CANCER CHALLENGE": Control-arm data of several studies among patients with metastatic castration-resistant prostate cancer (mCRPC) are currently available through PDS. These data sets have multiple potential uses. The "Prostate Cancer Challenge" will ask the cancer research community to use clinical trial data deposited in the PDS website to address key research questions regarding mCRPC. General themes that could be explored by the cancer community are described in this article: prognostic models evaluating the influence of pretreatment factors on survival and patient-reported outcomes; comparative effectiveness research evaluating the efficacy of standard of care therapies, as illustrated in our companion article comparing mitoxantrone plus prednisone with prednisone alone; effects of practice variation in dose, frequency, and duration of therapy; level of patient adherence to elements of trial protocols to inform the design of future clinical trials; and age of subjects, regional differences in health care, and other confounding factors that might affect outcomes.
UNASSIGNED
The number of data sets available and the lack of experimental-arm data limit the potential scope of research using the current PDS. The number of trials is expected to grow exponentially over the next year and may include multiple cancer settings, such as breast, colorectal, lung, hematologic malignancy, and bone marrow transplantation. Other potential limitations include the retrospective nature of the data analyses performed using PDS and its generalizability, given that clinical trials are often conducted among younger, healthier, and less racially diverse patient populations. Methodological challenges exist when combining individual patient data from multiple clinical trials; however, advancements in statistical methods for secondary database analysis offer many tools for reanalyzing data arising from disparate trials, such as propensity score matching. Despite these concerns, few if any comparable data sets include this level of detail across multiple clinical trials and populations.
CONCLUSIONS
Access to large, late-phase, cancer-trial data sets has the potential to transform cancer research by optimizing research efficiency and accelerating progress toward meaningful improvements in cancer care. This type of platform provides opportunities for unique research projects that can examine relatively neglected areas and that can construct models necessitating large amounts of detailed data. The full potential of PDS will be realized only when multiple tumor types and larger numbers of data sets are available through the website.
Publication
Journal: Mutagenesis
October/31/2012
Abstract
Reliable methods for evaluation of toxicity from particles, such as manufactured nanoparticles, are needed. One promising tool is the comet assay, often used to measure DNA breaks (strand breaks and alkali-labile sites) as well as oxidatively damaged DNA, the latter by addition of specific DNA repair enzymes such as formamidopyrimidine DNA glycosylase (FPG). The aim of this study was to investigate the use of the comet assay for analysis of DNA oxidation by a range of micro- and nanoparticles in the lung cell lines A549 and BEAS-2B and to test the hypothesis that nanoparticles present in the cells during the assay performance may interact with FPG. This was done by investigating the ability of micro- and nanoparticles (stainless steel, subway particles, MnO(2), Ag, CeO(2), Co(3)O(4), Fe(3)O(4), NiO and SiO(2)) to induce DNA breaks, oxidatively damaged DNA (FPG sites, dominantly 8-oxoguanine), intracellular production of reactive oxygen species (ROS) and non-cellular oxidation of the DNA base guanine, as well as by studying interactions of the particles and their released ions with FPG. Several particles caused DNA breaks, but low levels of FPG sites. The ability of FPG to detect DNA oxidation induced by a photosensitiser was however shown. An oxidative capacity of the particles was indicated by increased levels of intracellular ROS, and especially Ag and subway particles caused non-cellular oxidation of guanine. Incubation of FPG with the particles led to less FPG activity, particularly with nanoparticles of Ag but also with CeO(2), Co(3)O(4) and SiO(2). Further investigations of these particles revealed that for Ag, the decreased activity was mainly due to released Ag ions, whereas for CeO(2) and Co(3)O(4), FPG interactions were due to the particles. We conclude that measurement of oxidatively damaged DNA in cells exposed to nanoparticles may be underestimated in the comet assay due to interactions with FPG.
Publication
Journal: International Journal of Molecular Sciences
February/4/2013
Abstract
Owing to their radical scavenging and UV-filtering properties, ceria nanoparticles (CeO(2)-NPs) are currently used for various applications, including as catalysts in diesel particulate filters. Because of their ability to filter UV light, CeO(2)-NPs have garnered significant interest in the medical field and, consequently, are poised for use in various applications. The aim of this work was to investigate the effects of short-term (24 h) and long-term (10 days) CeO(2)-NP exposure to A549, CaCo2 and HepG2 cell lines. Cytotoxicity assays tested CeO(2)-NPs over a concentration range of 0.5 μg/mL to 5000 μg/mL, whereas genotoxicity assays tested CeO(2)-NPs over a concentration range of 0.5 μg/mL to 5000 μg/mL. In vitro assays showed almost no short-term exposure toxicity on any of the tested cell lines. Conversely, long-term CeO(2)-NP exposure proved toxic for all tested cell lines. NP genotoxicity was detectable even at 24-h exposure. HepG2 was the most sensitive cell line overall; however, the A549 line was most sensitive to the lowest concentration tested. Moreover, the results confirmed the ceria nanoparticles' capacity to protect cells when they are exposed to well-known oxidants such as H(2)O(2). A Comet assay was performed in the presence of both H(2)O(2) and CeO(2)-NPs. When hydrogen peroxide was maintained at 25 μM, NPs at 0.5 μg/mL, 50 μg/mL, and 500 μg/mL protected the cells from oxidative damage. Thus, the NPs prevented H(2)O(2)-induced genotoxic damage.
Publication
(16764658; CEO; 10.1111/j.1442-9071.2006.01224.x)
Journal: Clinical and Experimental Ophthalmology
August/7/2006
Abstract
The authors report a retinal branch artery occlusion occurring after facial injection of a dermal filler. The superior temporal artery showed occlusion due to a clearly visible long and fragmented embolus suggestive of gel and clearly distinguishable from calcific or cholesterol emboli. The authors suppose that hyaluronic acid gel was embolized in the patient. The embolized material is supposed to enter the ocular circulation through retrograde arteriolar flow after intra-arterial injection into one of the peripheral branches of the ophthalmic artery. If there is any evidence of a visual problem after facial injection of a dermal filler, prompt consultation of an ophthalmologist is recommended.
Publication
Journal: Food Chemistry
July/17/2016
Abstract
A novel antimicrobial packaging material was obtained by incorporating cinnamon essential oil/β-cyclodextrin inclusion complex (CEO/β-CD-IC) into polylacticacid (PLA) nanofibers via electrospinning technique. The CEO/β-CD-IC was prepared by the co-precipitation method and SEM and FT-IR spectroscopy analysis indicated the successful formation of CEO/β-CD-IC, which improved the thermal stability of CEO. The CEO/β-CD-IC was then incorporated into PLA nanofibers by electrospinning and the resulting PLA/CEO/β-CD nanofilm showed better antimicrobial activity compared to PLA/CEO nanofilm. The minimum inhibitory concentration (MIC) of PLA/CEO/β-CD nanofilm against Escherichia coli and Staphylococcus aureus was approximately 1 mg/ml (corresponding CEO concentration 11.35 μg/ml) and minimum bactericidal concentration (MBC) was approximately 7 mg/ml (corresponding CEO concentration 79.45 μg/ml). Furthermore, compared with the casting method, the mild electrospinning process was more favorable for maintaining greater CEO in the obtained film. The PLA/CEO/β-CD nanofilm can effectively prolong the shelf life of pork, suggesting it has potential application in active food packaging.
Publication
Journal: Human Reproduction
November/8/2011
Abstract
BACKGROUND
Highly reactive carbonyl compounds formed during glycolysis, such as methylglyoxal (MG), can lead to the formation of 'advanced glycation end products' (AGE) and carbonyl stress. Toxic AGEs are suspected to accumulate and play a role in reducing quality and developmental potential of mammalian oocytes of aged females and in PCOS and diabetic patients. Whether and how MG and AGE affect young and aged oocytes at the cellular level is unknown.
METHODS
The study consists of three parts. In Part A expression of MG-detoxifying enzymes glyoxalases 1 and 2 was analysed by RT-PCR at different stages of maturation in denuded oocytes (DO), cumulus-enclosed oocytes (CEO) and metaphase (M)II oocytes of the CD-1 mouse to obtain information on stage-specific susceptibility to carbonyl stress. DO and CEO from young and aged females and from stimulated cycles were exposed to MG during maturation in vitro to assess also age-related changes in sensitivity to carbonyl stress induced by MG. Induction of apoptosis by MG on in vitro maturing DO was assessed by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling test. In Part B of the study, DO from large antral follicles of ovaries of adult, young MF-1 mice in late diestrous were exposed to MG to assess direct influences of MG and AGEs formed during continuous exposure to MG on rate and kinetics of maturation to MII, on DNA integrity (by γ-H2AX staining) in the germinal vesicle (GV) stage, and on spindle formation and chromosome alignment (by tubulin and pericentrin immunofluorescence and polarization microscopy), and chromosome segregation (by C-banding) during in vitro maturation. Since MG and AGEs can affect functionality of mitochondria in Part C, mitochondrial distribution and membrane potential was studied using JC-1 probe. Expression of a redox-sensitive mito-Grx1-roGFP2 protein in mitochondria of maturing oocytes by confocal laser scanning microscopy was employed to determine the inner mitochondrial glutathion (GSH)/glutathion disulfide (GSSG)-dependent redox potential.
RESULTS
Part A revealed that mRNA for glyoxalases decreases during meiotic maturation. Importantly, cumulus from aged mice in CEO obtained from stimulated cycles does not protect oocytes efficiently from MG-induced meiotic arrest during in vitro maturation. Part B showed that the MG-induced meiotic delay or arrest is associated with significant rises in spindle aberrations, chromosome congression failure and aberrant telophase I in oocytes. MG exposure of meiotically arrested GV-stage oocytes significantly increases the numbers of γ-H2AX spots in the nucleus suggesting increased DNA damage, while MG exposure during maturation affects chromatin condensation and induces chromosome lagging at anaphase I. Moreover, Part C revealed that carbonyl stress by chronic exposure to MG is associated with delays in changes in mitochondrial distribution and altered inner-mitochondrial GSH/GSSG redox potential, which might be particularly relevant for cytoskeletal dynamics as well as processes after fertilization. Sensitivity to a meiotic block by MG appears dependent on the genetic background.
CONCLUSIONS
The sensitivity to carbonyl stress by MG appears to increase with maternal age. Since MG-exposure induces DNA damage, meiotic delay, spindle aberrations, anaphase I lagging and epimutation, aged oocytes are particularly at risk for such disturbances in the absence of efficient protection by cumulus. Furthermore, disturbances in mitochondrial distribution and redox regulation may be especially critical for fertilization and developmental competence of oocytes exposed to MG and carbonyl stress before or during maturation, for instance, in aged females, or in PCOS or diabetic patients, in agreement with recent suggestions of correlations between poor follicular and embryonic development, lower pregnancy rate and presence of toxic AGEs in serum, irrespective of age.
Publication
Journal: Nature Materials
March/25/2012
Abstract
Fuel cells, and in particular solid-oxide fuel cells (SOFCs), enable high-efficiency conversion of chemical fuels into useful electrical energy and, as such, are expected to play a major role in a sustainable-energy future. A key step in the fuel-cell energy-conversion process is the electro-oxidation of the fuel at the anode. There has been increasing evidence in recent years that the presence of CeO(2)-based oxides (ceria) in the anodes of SOFCs with oxygen-ion-conducting electrolytes significantly lowers the activation overpotential for hydrogen oxidation. Most of these studies, however, employ porous, composite electrode structures with ill-defined geometry and uncontrolled interfacial properties. Accordingly, the means by which electrocatalysis is enhanced has remained unclear. Here we demonstrate unambiguously, through the use of ceria-metal structures with well-defined geometries and interfaces, that the near-equilibrium H(2) oxidation reaction pathway is dominated by electrocatalysis at the oxide/gas interface with minimal contributions from the oxide/metal/gas triple-phase boundaries, even for structures with reaction-site densities approaching those of commercial SOFCs. This insight points towards ceria nanostructuring as a route to enhanced activity, rather than the traditional paradigm of metal-catalyst nanostructuring.
Publication
(16764648; CEO; 10.1111/j.1442-9071.2006.01212.x)
Journal: Clinical and Experimental Ophthalmology
August/7/2006
Abstract
BACKGROUND
To evaluate the systemic and thrombophilic risk factors for retinal vein occlusion (RVO) and to determine whether the elevated level of soluble endothelial protein C receptor (sEPCR) is a risk factor for thrombosis.
METHODS
In this case-control study, 56 patients with central RVO (CRVO), 26 patients with branch RVO (BRVO) and 78 healthy sex- and age-matched subjects were enrolled. Following ophthalmological examination, venous blood was analysed for glucose, lipid profile, lipoprotein (a), homocysteine, activated partial thromboplastin time, fibrinogen, factor VIII, protein C activity, protein S activity, activated protein C resistance, antithrombin III activity, lupus anticoagulant, anti-cardiolipin antibody, anti-phospholipid antibody, sEPCR, factor V Leiden mutation and prothrombin G20210A mutation.
RESULTS
Apart from hypertension, glaucoma, lipoprotein (a), homocysteine and factor VIII, elevated levels of sEPCR were found to be a risk factor for CRVO (odds ratio, 1.02; 95% confidence interval, 1.007-1.028; P = 0.001). Patients with CRVO had significantly higher levels of sEPCR than those with BRVO and controls (respectively, 160.1 +/- 83.8, 116.8 +/- 65.2 and 111.3 +/- 60.5; P = 0.005). Moreover, 39% of patients with CRVO had levels of sEPCR more than 200 ng/mL, and only 5% of controls and 11% of patients with BRVO had similar high levels.
CONCLUSIONS
Besides known classical risk factors, elevated levels of sEPCR seem to be an important candidate risk factor for especially CRVO.
Publication
Journal: Reproduction
June/15/2003
Abstract
The aim of this study was to investigate whether apoptosis occurs in cumulus cells during in vitro maturation (IVM) of bovine cumulus-enclosed oocytes (CEOs). The bovine CEOs obtained from ovaries from an abattoir were cultured for 24 h in IVM medium in the presence or absence of 10% (v/v) fetal bovine serum. The developmental competence of enclosed oocytes, as assessed by the development of the blastocyst after IVF, was significantly higher in the serum-treated group than in the control group. The morphological features of apoptosis that were analysed by orcein staining were hardly detectable in the cumulus cells at the start (0 h) of IVM, but were evident at the end (24 h) of IVM both in the control and serum-treated groups. Genomic DNA was extracted from CEOs at 0, 6, 12, 18 and 24 h of IVM and subjected to ligation-mediated PCR (LM-PCR) to detect apoptotic internucleosomal DNA fragmentation. DNA fragmentation was hardly detectable at the start of IVM, but increased in a time-dependent manner as the IVM culture proceeded. DNA fragmentation was not observed in the oocytes, indicating that fragmentation occurs in cumulus cells. The degree of fragmentation was lower in the serum-treated group compared with the control group. The LM-PCR analysis of DNA extracted from CEOs at 24 h of IVM, in which the DNA had been pretreated with Klenow enzyme or T4 DNA polymerase, revealed that the characteristic forms of the DNA ends generated during cumulus cell apoptosis were mainly 3'-overhangs and blunt ends. In conclusion, the results of the present study demonstrate that cumulus cells in bovine CEOs spontaneously undergo apoptosis during IVM. The degree of apoptosis may be correlated with the developmental competence of the enclosed oocytes.
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