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Richardson LC, Bazaco MC, Parker CC, Dewey-Mattia D, Golden N, Jones K, Klontz K, Travis C, Kufel JZ, Cole D. An Updated Scheme for Categorizing Foods Implicated in Foodborne Disease Outbreaks: A Tri-Agency Collaboration. Foodborne Pathog Dis 2017; 14:701-710. [PMID: 28926300 DOI: 10.1089/fpd.2017.2324] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Foodborne disease data collected during outbreak investigations are used to estimate the percentage of foodborne illnesses attributable to specific food categories. Current food categories do not reflect whether or how the food has been processed and exclude many multiple-ingredient foods. MATERIALS AND METHODS Representatives from three federal agencies worked collaboratively in the Interagency Food Safety Analytics Collaboration (IFSAC) to develop a hierarchical scheme for categorizing foods implicated in outbreaks, which accounts for the type of processing and provides more specific food categories for regulatory purposes. IFSAC also developed standard assumptions for assigning foods to specific food categories, including some multiple-ingredient foods. The number and percentage of outbreaks assignable to each level of the hierarchy were summarized. RESULTS The IFSAC scheme is a five-level hierarchy for categorizing implicated foods with increasingly specific subcategories at each level, resulting in a total of 234 food categories. Subcategories allow distinguishing features of implicated foods to be reported, such as pasteurized versus unpasteurized fluid milk, shell eggs versus liquid egg products, ready-to-eat versus raw meats, and five different varieties of fruit categories. Twenty-four aggregate food categories contained a sufficient number of outbreaks for source attribution analyses. Among 9791 outbreaks reported from 1998 to 2014 with an identified food vehicle, 4607 (47%) were assignable to food categories using this scheme. Among these, 4218 (92%) were assigned to one of the 24 aggregate food categories, and 840 (18%) were assigned to the most specific category possible. CONCLUSIONS Updates to the food categorization scheme and new methods for assigning implicated foods to specific food categories can help increase the number of outbreaks attributed to a single food category. The increased specificity of food categories in this scheme may help improve source attribution analyses, eventually leading to improved foodborne illness source attribution estimates and enhanced food safety and regulatory efforts.
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Affiliation(s)
- LaTonia Clay Richardson
- 1 U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) , Division of Foodborne, Waterborne, and Environmental Diseases, Atlanta, Georgia
| | - Michael C Bazaco
- 2 U.S. Department of Health and Human Services, Food and Drug Administration (FDA) , College Park, Maryland
| | - Cary Chen Parker
- 2 U.S. Department of Health and Human Services, Food and Drug Administration (FDA) , College Park, Maryland
| | - Daniel Dewey-Mattia
- 1 U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) , Division of Foodborne, Waterborne, and Environmental Diseases, Atlanta, Georgia
| | - Neal Golden
- 3 U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) , Washington, District of Columbia
| | - Karen Jones
- 4 Arnold School of Public Health, University of South Carolina , Columbia, South Carolina
| | - Karl Klontz
- 2 U.S. Department of Health and Human Services, Food and Drug Administration (FDA) , College Park, Maryland
| | - Curtis Travis
- 3 U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) , Washington, District of Columbia
| | - Joanna Zablotsky Kufel
- 3 U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) , Washington, District of Columbia
| | - Dana Cole
- 5 U.S. Department of Agriculture, Animal and Plant Health Inspection Service , Fort Collins, Colorado
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Trägårdh J, Macrae K, Travis C, Amor R, Norris G, Wilson SH, Oppo GL, McConnell G. A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope. J Microsc 2015; 259:66-73. [PMID: 25864964 PMCID: PMC4975716 DOI: 10.1111/jmi.12249] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/24/2015] [Indexed: 12/03/2022]
Abstract
We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic‐scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light‐collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife‐edge method has several advantages over alternative knife‐edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited.
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Affiliation(s)
- J Trägårdh
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - K Macrae
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K.,Department of Physics, University of Strathclyde, Glasgow, U.K
| | - C Travis
- Department of Physics, University of Strathclyde, Glasgow, U.K
| | - R Amor
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - G Norris
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
| | - S H Wilson
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K.,Department of Physics, University of Strathclyde, Glasgow, U.K
| | - G-L Oppo
- Department of Physics, University of Strathclyde, Glasgow, U.K
| | - G McConnell
- Centre for Biophotonics, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, U.K
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Travis C, Norris G, McConnell G, Oppo GL. Energy shedding during nonlinear self-focusing of optical beams. Opt Express 2013; 21:23459-23470. [PMID: 24104260 DOI: 10.1364/oe.21.023459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Self-focusing of intense laser beams and pulses of light in real nonlinear media is in general accompanied by material losses that require corrections to the conservative Nonlinear Schrödinger equations describing their propagation. Here we examine loss mechanisms that exist even in lossless media and are caused by shedding of energy away from the self-trapping beam making it to relax to an exact solution of lower energy. Using the conservative NLS equations with absorbing boundary conditions we show that energy shedding not only occurs during the initial reshaping process but also during oscillatory propagation induced by saturation of the nonlinear effect. For pulsed input we also show that, depending on the sign and magnitude of dispersion, pulse splitting, energy shedding, collapse or stable self-focusing may result.
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Travis C, Obenshain KR, Gunter JT, Regens JL, Whipple C. Using multimedia modeling to expedite site characterization. Environ Sci Pollut Res Int 2004; 11:302-306. [PMID: 15506632 DOI: 10.1007/bf02979643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
GOAL, SCOPE AND BACKGROUND This paper uses two case studies of U.S. Department of Energy nuclear weapons complex installations to illustrate the integration of expedited site characterization (ESC) and multimedia modeling in the remedial action decision making process. CONCEPTUAL SITE MODELS, MULTIMEDIA MODELS, AND EXPEDITED SITE CHARACTERIZATION: Conceptual site models outline assumptions about contaminates and the spatial/temporal distribution of potential receptors. Multimedia models simulate contaminant transport and fate through multiple environmental media, estimate potential human exposure via specific exposure pathways, and estimate the risk of cancer and non-cancer health outcomes. ESC relies on using monitoring data to quantify the key components of an initial conceptual site model that is modified iteratively using the multimedia model. CASE STUDIES Two case studies are presented that used the ESC approach: Los Alamos National Laboratory (LANL) and Pantex. LANL released radionuclides, metals, and organic compounds, into canyons surrounding the facility. The Pantex Plant has past waste management operations which included burning chemical wastes in unlined pits, burying wastes in unlined landfills, and discharging plant wastewaters into on-site surface waters. CONCLUSIONS The case studies indicate that using multimedia models with the ESC approach can inform assessors about what, where, and how much site characterization data needs to be collected to reduce the uncertainty associated with risk assessment. Lowering the degree of uncertainty reduces the time and cost associated with assessing potential risk and increases the confidence that decision makers have in the assessments performed.
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Albertini R, Clewell H, Himmelstein MW, Morinello E, Olin S, Preston J, Scarano L, Smith MT, Swenberg J, Tice R, Travis C. The use of non-tumor data in cancer risk assessment: reflections on butadiene, vinyl chloride, and benzene. Regul Toxicol Pharmacol 2003; 37:105-32. [PMID: 12662914 DOI: 10.1016/s0273-2300(02)00019-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The estimation and characterization of a cancer risk is grounded in the observation of tumors in humans and/or experimental animals. Increasingly, however, other kinds of data (non-tumor data) are finding application in cancer risk assessment. Metabolism and kinetics, adduct formation, genetic damage, mode of action, and biomarkers of exposure, susceptibility, and effects are examples. While these and other parameters have been studied for many important chemicals over the past 30-40 years, their use in risk assessments is more recent, and new insights and opportunities are continuing to unfold. To provide some perspective on this field, the ILSI Risk Science Institute asked a select working group to characterize the pertinent non-tumor data available for 1,3-butadiene, benzene, and vinyl chloride and to comment on the utility of these data in characterizing cancer risks. This paper presents the findings of that working group and concludes with 15 simple principles for the use of non-tumor data in cancer risk assessment.
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Travis C. Risk analysis: an overview. Folia Histochem Cytobiol 2002; 39 Suppl 2:17-9. [PMID: 11820591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Risk analysis increasingly is considered as an integral part of the environmental management decision-making process. Risk, defined as the probability of occurrence of a particular adverse effect on human health or the environment, should not be confounded with hazard, defined as a source of potential injury independent of occurrence. Risk analysis has to be followed by risk management. Some opponents of risk analysis make the reproach that the science used in risk analysis is immature and consequently that the entire process in laden with hidden value judgments. Attempts to overcome these critics are increasingly based on the use of robust biologic data the final considered values system being efficacy-based, efficiency-based or equity-based. Globalization has brought with it new problems, and there is an urgent need to improve risk analysts; to increase its public acceptability and to establish consensus regarding solutions to global environmental problems. In this context biologic-based models and biomarkers hold, the greatest promise for improving risk assessment. These considerations are illustrated by a few examples, also pertaining to low-dose extrapolation and to the problem of thresholds for carcinogenesis. Future directions for development are evoked.
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Travis C, Taylor CA, Mayhew HE. Evaluating residency applicants: stable values in a changing market. Fam Med 1999; 31:252-6. [PMID: 10212766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND AND OBJECTIVES A 1994 study found significant differences in the way family practice and OB-GYN residency directors ranked the importance of components of the residency application package. Family practice residency directors favored qualitative measures (dean's letter, personal statement), and OB-GYN residency directors favored quantitative measures (transcripts, National Board of Medical Examiners score). The authors of the 1994 study hypothesized that the differences could be attributed to specialty competitiveness and philosophy. Our study reexamined family practice rankings of these same application components to determine if the programs, with increased competition for residency positions, had changed their values. METHODS We surveyed all Accreditation Council for Graduate Medical Education-approved residency directors, using the core questions from the 1994 study, plus 2 additional questions. RESULTS The component rankings in 1997 were virtually identical to the rankings in 1994. The new variables, computed to identify competitiveness, failed to elicit any meaningful or consistent differences. CONCLUSIONS Program directors have remained relatively stable in favoring the qualitative aspects of the application package, ranking the dean's letter and personal statement consistently in the top 3 positions. This stability is found across time and independent of success in the National Resident Matching Program and number of US graduate applicants. Residency directors have not increased their reliance on quantitative measures.
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Affiliation(s)
- C Travis
- Department of Family Medicine, Medical College of Ohio, Toledo, USA
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Abstract
Rat liver epithelial cells (RLE) are suspected to be pluripotent hepatic stem cells that give rise to a diverse variety of liver tumors. The molecular events responsible for transformation of these cells and the diversity of the tumor phenotypes remains to be fully elucidated. We examined the genotype and phenotype of RLE cells infected with retroviral shuttle vectors carrying a neomycin resistance (neor) Ha-ras or a lacZ gene. WBneoIII, WBrasIII and WBlacZ cell lines were examined for evidence of a transformed phenotype by comparing their behavior with the parental strain (WB-344) and with WBneo-C-II and WBrasII cells. Confluent cultures of WBneo-C-II and WBrasII cells were found to contain significantly higher numbers of total cells than the other cell lines. The growth rate of WBneo-C-II and WBrasII cells were faster than that of the parental cell line. Addition of epidermal growth factor (EGF) to the medium was found to stimulate the growth rate of WBneo-C-II cells and to induce anchorage independent growth (AIG). No cell line produced tumors in nude mice (nu/nu) except WBrasII cells. Radioimmunoprecipitation studies and sequencing of the p53 exons 5-8 indicate WBneo-C-II, and WBrasII cells produce a mutant p53. Northern blot analysis showed an increased expression of c-myc mRNA in WBneo-C-II and WBrasII cells. These results demonstrate that alterations in critical growth and differentiation controlling genes have occurred in WBrasII cells which may, independent of or in conjunction with ras insertion, cause the transformed phenotype.
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Affiliation(s)
- C Dees
- Risk Analysis Section, Oak Ridge National Laboratory, TN 37831-6109, USA
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Dees C, Garrett S, Henley D, Travis C. Effects of 60-Hz fields, estradiol and xenoestrogens on human breast cancer cells. Radiat Res 1996; 146:444-52. [PMID: 8927716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
If exposure to xenoestrogens or electromagnetic fields (EMFs) such as 60 Hz contributes to the etiology of breast cancer, it is likely that they must stimulate the growth of breast cells, damage genetic material or enhance the effects of other mitogenic or mutagenic agents (co-promotion). Therefore, the ability of xenoestrogens or exposure to 60-Hz fields to stimulate the entry of growth-arrested human breast cancer cells into the cell cycle was determined using cyclin-dependent kinase 2 (Cdk2) activity, synthesis of cyclin D1 and cdc2 activity. Exposure of estrogen receptor-positive MCF-7 or T-47D cells to estrogen and xenoestrogens (DDT and Red No. 3) increased Cdk2 and cyclin B1-cdc2 activity and cyclin D1 synthesis. Exposure of breast cancer cells to 12 mG or 1 or 9 G electromagnetic fields at 60 Hz failed to stimulate Cdk2 or cyclin B1-cdc2 activity or cyclin D1 synthesis. Simultaneous co-exposure of cells to 60-Hz fields and chemical promoters did not enhance Cdk2 activation above the levels produced by the chemical promoter alone. Estrogen and xenoestrogens also stimulated binding of the estrogen receptor to the estrogen receptor element but the EMF did not. Phorbol 12-myristate 13-acetate (PMA) induced phosphorylation of p53 and pRb1O5 in MCF-7 cells, but EMF exposure had no effect. DNA-damaging chemotherapeutic agents and Red Dye No. 3 were found to increase p53 site-specific DNA binding in breast cancer cells, but EMF exposure did not. Differential display analysis failed to detect any effect of EMF exposure on gene expression in MCF-7 cells, whereas the effects of estradiol were detected. These studies suggest that estrogen and xenoestrogens stimulate growth-arrested breast cancer cells to enter the growth cycle, but EMF exposure does not. Site-specific p53-DNA binding was increased in MC F-7 cells treated with DNA-damaging agents, but not by EMF exposure. EMF exposure does not appear to act as a promoter or DNA-damaging agent for human breast cancer cells in vitro.
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Affiliation(s)
- C Dees
- Health Sciences Research Division, Oak Ridge National Laboratory, Tennessee 37831-6109, USA
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Yen A, Williams M, Platko JD, Der C, Hisaka M, Feigin AM, Wang C, Stiles CD, Cavalcanti TC, Guimaraesr F, Gumerato HF, Tahinc QS, Ratnan AV, Su HJ, Bxrle DD, Basson MD, Hong F, Bianchi-Santamaria A, Santamaria L, Bianchi-Santamaria A, Fedeli S, Santamaria L, Coral A, Lamartiniere P, Pence BC, Butler MJ, Dunn DM, Miller MF, Wickramasinghe NSMD, Jo H, McDonald JM, Hardy RW, Fernandes G, Chandrasekar B, Venkatraman JT, Kuratko CN, Pence BC, Bhatia M, Kirkland JB, Meckling-Gill KA, Sarkar NH, Li H, Zhao W, Atkinson TG, Martin D, de Salis H, Meckling-Gill KA, Teixeira C, Pratt C, Kulkarni AA, Sajan M, Datta K, Roy P, Kulkarni AP, Gopalakrishna R, Chen ZH, Gundimeda U, Braunhut SJ, Medeiros D, Freeman MR, Moses MA, Yang GY, Shamsuddin AM, Vucenik I, Yang GY, Shamsuddin AM, Paisley EA, Kaput J, Mangian HJ, Visek WJ, Hohl RJ, Lewis K, Chung KT, Chen W, Zhou Y, Fu PP, Hart RW, Chou MW, Kagan VE, Yalowich JC, Tyurina JY, Tyurin VA, Ritov VB, Goldman R, Stoyanovsky DA, Menshikova EV, Kagan VE, Zugmaier G, Jäger R, Gottardis M, Havemann K, Knabbe C, Hagerman RA, Fischer SM, Locniskar MF, Black HS, Okotie-Eboh G, Gerguis J, Urban JI, Thornby JI, Merrill H, Sauer LA, Dauchy RT, Connolly JM, Rose DP, Gensler HL, Gerrish K, Peng YM, Xu MJ, Jenski LJ, Zerouga M, Zhang L, Stillwell W, Homayoun P, Gupta MK, Lente F, Tuason U, Budd T, Yazlovitskaya M, Melnykovych G, Matthew JA, Middleton S, Prior A, Kennedy HJ, Fellows IW, Johnson IT, Lee PP, Ip MM, Gercel-Taylor C, Taylor DD, Pretlow TP, Hudson L, O’Riordan MA, Pretlow TG, Cohen LA, Zang E, Rivenson A, Sherman AR, Hrabinski D, Berger V, Dees C, Henley D, Ardies M, Travis C, Benbrook DM, Brewer K, Heldermon C, Nunez E, Walisewaki P, Reynolds CP, Einhorn P, Schindler P, Zuo JJ, Khan AA, Avramis VI, Villablanca JG, Gaposchkin DP, Broitman SA, Kosacoisky SC, Broitman SA, Shlyankevich M, Lee R, Garden K, Lee YC, Surh YJ, Katdare MS, Osborne MP, Telang NT, Shivapurkar N, Tang Z, Alabaster O, Jaskeiwicz JA, Zhao Y, Shimomura Y, Crabb DW, Harris RA, Zaleski J, Richter PA, Kwei GY, Kauffman FC, Hilakivi-Clarke L, Onojafe I, Cho E, Clarke R, Lippman ME. Abstracts. Advances in Experimental Medicine and Biology 1995. [DOI: 10.1007/978-1-4899-0949-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Phorbol 12-myristate, 13-acetate (PMA) is a known protein kinase C activator (PKC); benzene, chloroform, and toluene have also been reported to be PKC activators. We examined the effects of these three solvents on the phosphorylation of p53 in treated cells. Hyperphosphorylated p53 was found when p53 was immunoprecipitated from rat liver epithelial cell extracts treated with any of the solvents or PMA. The solvents also resulted in hyper-phosphorylation of human p53 produced by transfection of Saos-2 cells with a eucaryotic expression vector. Increased phosphorylation of p53 induced by the solvents was also observed through in vitro assays. Hyperphosphorylation of p53 may be involved in tumor promotion by benzene, toluene and chloroform.
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Affiliation(s)
- C Dees
- Molecular Toxicology Group, Oak Ridge National Laboratory, TN 37831-6109
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Abstract
Male and female B6C3F1 mice were given trichloroacetate (TCA) by gavage for 11 days. Livers from untreated male and female mice were unremarkable by histopathologic examination. In livers from mice receiving 1000 mg/kg body weight, the centrolobular hepatic cords showed slight changes, which included increased eosinophilic staining and rare apoptosis. Areas in the intermediate zone were noted where the architecture of the liver hepatic cords was subtly changed. The changes in cord architecture seemed to define nodular areas where cellular proliferation in animals treated with TCA had occurred. No histopathologic differences were noted between the livers of treated or control, male and female animals. Mitosis and DNA synthesis were examined using incorporation of [3H]thymidine into liver cells. [3H]Thymidine incorporation into extracted liver DNA of animals receiving TCA was significantly increased over controls in all treatment groups. Autoradiographic examination of liver sections showed that the incorporation of label in control animals was predominantly in peri-sinusoidal cells, whereas the majority of radiolabel incorporation in TCA-treated animals was found in intermediate zone cells that appeared to be mature hepatocytes. No outstanding differences in the distribution of radiolabel in the liver sections from male or female mice were noted. When incorporation of [3H]thymidine was quantified by enumeration of labeled liver cells following autoradiography, incorporation of the radiolabel into hepatocytes increased with the dose of TCA given but there was no increase in radiolabel in peri-sinusoidal cells. Increased mitotic figures in intermediate zone cells resembling mature hepatocytes were noted in all mice treated with TCA. These results suggest that increased DNA synthesis and mitosis may contribute tumorigenesis by TCA.
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Affiliation(s)
- C Dees
- Risk Analysis Section, Health and Safety Research Division, Oak Ridge National Laboratory, TN 37831-6109
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Abstract
Male and female B6C3F1 mice were given TCE by gavage for 10 days. No histopathologic changes in the livers from control male and female mice were found. Moderate changes around central veins were noted in male or female mice that received 1000 mg/kg/body weight TCE. Histopathological changes included an increase in cytoplasmic eosinophilic staining and apoptosis around the central veins. Mitosis and DNA synthesis were examined using incorporation of [3H]thymidine into liver cells. Incorporation of [3H]thymidine was significantly increased in the DNA of animals receiving TCE. Total liver DNA extracted from TCA-treated mice was not significantly different than those of control groups. Autoradiographic examination of liver sections showed that the incorporation of label in control animals was primarily in perisinusoidal cells. The majority of radiolabel incorporation in TCE-treated mice was found in intermediate zone cells that appeared to be mature hepatocytes. No outstanding differences in the distribution of radiolabel in the liver from male or female mice were noted. When incorporation of [3H]thymidine was quantified by enumeration of labeled hepatocytes following autoradiography, incorporation of the radiolabel into hepatocytes increased proportionally to the applied dose of TCE, but did not increase in peri-sinusoidal cells. Increased mitotic figures in intermediate zone cells resembling mature hepatocytes were found in all mice treated with TCE. These results suggest that liver cell DNA synthesis and mitosis are stimulated by TCE and that these effects may be in part responsible for transformation of liver cells in these mice.
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Affiliation(s)
- C Dees
- Risk Analysis Section, Oak Ridge National Laboratory, TN
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Hattemer-Frey HA, Travis C. 23 March 1992. Toxicol Ind Health 1992. [DOI: 10.1177/074823379200800308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | - Curtis Travis
- Director, Center for Risk Management Oak Ridge National Laboratory P.O. Box 2008, MS-6109 Oak Ridge, TN 37831-6109
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Rodrigo JJ, Thompson E, Travis C. Deep-freezing versus 4 degrees preservation of avascular osteocartilaginous shell allografts in rats. Clin Orthop Relat Res 1987:268-75. [PMID: 3552356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Osteocartilaginous allografts (distal femurs of rats) were stored at 4 degrees for six, 12, 24, and 48 hours and at -80 degrees for five days and then evaluated for viability of the bone and cartilage. Storage at 4 degrees for 12 or 24 hours had little effect on cartilage viability but decreased bone viability to 40% and 10% of controls, respectively. Storage at -80 degrees for five days resulted in nonviable bone in all cases but showed an either/or response of cartilage, with high viability in two cases and nonviability in the other eight cases. In a second set of experiments, femurs from rats were stored in situ at 4 degrees for 12 or 24 hours or were harvested and stored at -80 degrees for five days, after which they were transplanted into rats of a different strain. The antibody response to each set of femurs was measured at two, six, and 12 weeks after operation. The 4 degrees storage resulted in a moderately decreased immunogenicity, whereas the storage at -80 degrees resulted in significantly reduced immunogenicity.
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Abstract
Efficacy and safety of azathioprine in 'high' and 'low' dose regimens in rheumatoid arthritis (RA), both in short-term studies and in follow-up over 40 months, have previously been shown. In the present report, 36 patients with RA treated with azathioprine (group I) and 49 age-matched patients with RA (group II), were studied to detect potential early markers of malignancy. Chest x-rays were similar to both groups. One patient in group I had a positive PAP smear and was subsequently found to have uterine carcinoma. Alpha-fetoprotein was positive in one patient in group I and none in group II. CEA was negative in all patients in group I, but positive in seven in group II. On chromosomal analysis group I showed a greater frequency of breakage. Group I showed lower serum folates and a highly significant number of megaloblastic features in marrow aspirates. In group I seven tumours, three being malignant, occurred while taking azathioprine, and in group II six tumours, one malignant, were identified (p = 0.17). The apparent increased risk of malignancy previously suggested by others warrants further studies with larger populations and over a continuous longer period.
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Rodrigo JJ, Sakovich L, Travis C, Smith G. Osteocartilaginous allografts as compared with autografts in the treatment of knee joint osteocartilaginous defects in dogs. Clin Orthop Relat Res 1978:342-9. [PMID: 365418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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